Transesophageal Echocardiography for Pediatric and Congenital Heart Disease [2 ed.] 3030571920, 9783030571924

Citation preview

Pierre C. Wong Wanda C. Miller-Hance  Editors

Transesophageal Echocardiography for Pediatric and Congenital Heart Disease Second Edition

123

Transesophageal Echocardiography for Pediatric and Congenital Heart Disease

Pierre C. Wong  •  Wanda C. Miller-Hance Editors

Transesophageal Echocardiography for Pediatric and Congenital Heart Disease Second Edition

Editors Pierre C. Wong Division of Pediatric Cardiology Department of Pediatrics Children's Hospital Los Angeles Keck School of Medicine University of Southern California Los Angeles, CA USA

Wanda C. Miller-Hance Department of Anesthesiology, Perioperative and Pain Medicine, Arthur S. Keats Division of Pediatric Cardiovascular Anesthesiology and Department of Pediatrics, Section of Cardiology Baylor College of Medicine, Texas Children’s Hospital; Texas Heart Institute Houston, TX USA

ISBN 978-3-030-57192-4    ISBN 978-3-030-57193-1 (eBook) https://doi.org/10.1007/978-3-030-57193-1 © Springer Nature Switzerland AG 2014, 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Preface

It is difficult to believe that nearly 8 years have passed since the first edition of this textbook. While we have been humbled and gratified by all of the enthusiastic and positive comments that we have received from many readers, truthfully, we had not expected to undertake a second edition. When our senior editor from Springer, Grant Weston, approached us to undertake an updated version of our book, we were skeptical. What more needed to be written? What had changed? What further could we offer to readers? As it turns out—quite a bit. We are all aware that medicine is constantly changing, and the discipline of transesophageal echocardiography (TEE)—particularly pediatric TEE—is no exception. Since the publication of our previous edition, there have been numerous changes and improvements in echocardiographic instrumentation, surgical and interventional techniques, and approaches to different cardiac diseases. There has also been significant growth in the number of pediatric patients with congenital heart disease (CHD) surviving to adulthood, leading to an ever-increasing adult CHD population that requires not only more practitioners with experience in adult CHD, but also alternative imaging techniques (including TEE) for this group of patients with often-challenging transthoracic echocardiographic imaging windows. All of these changes have increased the application of TEE for pediatric patients, and especially for the evaluation of CHD in both children and adults. In addition, new guidelines were recently published (by the Journal of the American Society of Echocardiography in 2019) that extensively discuss the comprehensive TEE evaluation of children and of all patients with CHD. So, the more we thought about it, the more we realized that the need for an updated and expanded version of this book was clear and compelling. This new edition of Transesophageal Echocardiography for Pediatric and Congenital Heart Disease has been thoroughly expanded and updated. It is now presented in a textbook format, with chapter goals clearly articulated, and with annotated, illustrative case studies at the end of most chapters. In addition, each chapter contains a Question and Answer section to help reinforce key concepts for the reader. The recommended TEE views, windows, and probe manipulations detailed in the abovementioned guidelines are reviewed extensively, and these serve as the foundation for this book. Nevertheless, despite all of these enhancements from the prior edition, our fundamental objective remains unchanged: that Transesophageal Echocardiography for Pediatric and Congenital Heart Disease will continue to serve as an invaluable resource for those who utilize this imaging approach in the care of pediatric patients and all patients with CHD, both children and adults. It is directed toward individuals with many types of expertise—cardiologists, surgeons, anesthesiologists, intensive care specialists, and sonographers—as well as trainees wishing to acquire basic knowledge or advance their understanding of the field. We again thank all readers of the previous edition for their support, encouragement, and helpful suggestions. We sincerely hope that all readers of this new edition will find this textbook informative, practical, and something they refer to often. Los Angeles, CA Houston, TX 

Pierre C. Wong Wanda C. Miller-Hance

v

Acknowledgments

The second edition of this textbook is once again the product of the collective experience and expertise of its many outstanding contributors and has been crafted through numerous hours of writing, researching, revising, and discussion. For the authors who are new to the second edition, the editors are grateful for your enthusiasm, dedication, and invaluable contributions. For the returning authors, the editors would again like to thank you for your recommitment and continued hard work. For all authors, we can honestly say that without your contributions, this unique textbook would not have been possible. The editors would also like to thank our publisher, Springer Nature, and particularly Grant Weston, Executive Editor of Medicine and Life Sciences Books at Springer Nature, who first approached us with the idea for a second edition, and convinced us of the importance of publishing an updated and more comprehensive textbook. We are thankful that he did. We are also indebted to our project coordinator at Springer Nature, Anand Shanmugam, whose guidance, support, and responsiveness propelled us forward and kept us focused despite our myriad other endeavors and responsibilities. From Pierre Wong: Thanks once more to my loving wife Yolanda, and my wonderful son Michael, for their continued encouragement and support. I really do not know how I could go forward without you. As always, thanks to all my colleagues at CHLA for their tireless efforts and never-ending spirit of collaboration. And finally, many thanks once again to my coeditor, Wanda. Working with you has always been a joy—a great experience that never gets old. From Wanda C. Miller-Hance: First and foremost, I praise God for granting me the blessing of being involved in this textbook project. Without Him, my contribution to this work would not have been possible. My heartfelt gratitude to the extraordinary people in my life for their encouragement, unwavering support, and endless patience. I am indebted to my mentors and colleagues, whom I have learned from over the years and continue to learn from every day. They have my deep admiration for their dedication and commitment to excellence. I celebrate the life of all the patients for whom I have had the privilege to care and who served as inspiration for this work. I am sincerely appreciative of the editorial assistance provided for this textbook by Stephen N. Palmer, PhD, ELS, and his excellent team of medical writers at the Texas Heart Institute. Special thanks go to my coeditor, Pierre, for conceiving the original idea for this project years ago and for his enthusiasm in updating the original work in this new edition. I will always be grateful to him for the opportunity to participate. It has been a pleasure and privilege to again work with him in this edition.

vii

Introduction

The past four decades have witnessed a dramatic evolution in the technology and clinical use of transesophageal echocardiography (TEE). Initially embraced by anesthesiologists in the early 1980s, TEE was used primarily as an intraoperative monitoring tool in adult patients. Major applications included the evaluation of cardiac function and ventricular filling, detection of myocardial ischemia, and investigation of the etiology of perioperative hemodynamic instability. During the next decade, rapid and significant advancements in transducer and ultrasound imaging technology catalyzed the development of TEE into an important imaging modality for evaluating both acquired and congenital heart disease (CHD). With the advent of single-plane imaging, followed by subsequent developments in biplane and omniplane/multiplane technology, both two- and three-dimensional TEE rapidly became recognized for their excellent imaging capabilities in adult patients. At the same time, TEE probe miniaturization, along with improvements in the spatial and temporal resolution of ultrasonic imaging, have led to the introduction and development of TEE for the pediatric population. Since then, the use of TEE in both pediatric and adult patients with CHD has increased, and the safety and efficacy of this imaging approach—even in neonates—has been widely validated. Thus, TEE has become established as an essential tool for the evaluation and management of pediatric patients with cardiac disease and for all patients (both pediatric and adult) with CHD. TEE continues to play a prominent role in the intraoperative setting and is widely recognized as a mainstay for the preoperative and postoperative assessment for CHD. Over time, however, the use of TEE has grown well beyond the operating room environment. It is now used in both inpatient and outpatient settings as a diagnostic and evaluative modality for children and adults with CHD. Even with alternative noninvasive imaging techniques such as cardiac magnetic resonance imaging and multislice, high-speed computerized tomography of the heart readily available, TEE remains an important and highly useful imaging approach for evaluating CHD in numerous settings and disease conditions. This includes the interventional cardiology setting, in which the profusion of new technologies and applications demands a reliable, real-time method of monitoring these procedures—and in this aspect, TEE remains at the forefront. In this textbook, we have endeavored to provide a comprehensive and unique reference on TEE, one dedicated exclusively to the many applications of this modality for a wide spectrum of congenital and acquired pathologies in children and CHD in the adult. Every chapter provides highly instructive textual material, including unique insights on TEE gleaned from the knowledge and experience of each author, supplemented by numerous pictorial and video examples. This textbook is not intended to be an encyclopedic compendium covering every aspect of TEE, nor is it meant to supplant the excellent references available for the echocardiographic evaluation of pediatric and CHD patients. Rather, we seek to provide a work that focuses and expands upon the applications of TEE in pediatric and adult patients, particularly in the setting of CHD, and one that complements other important resources. To this end, we have assembled the contributions of many highly regarded specialists in the field, who have generously shared their considerable expertise.

ix

Contents

1 Science of Ultrasound and Echocardiography���������������������������������������������������������   1 Pierre C. Wong 2 Instrumentation�����������������������������������������������������������������������������������������������������������  51 Ravi Managuli and Michael Brook 3 Indications and Guidelines in Pediatric and Congenital Heart Disease ���������������  71 Wanda C. Miller-Hance, Michael D. Puchalski, and Nancy A. Ayers 4 Structural Evaluation of the Cardiovascular System���������������������������������������������  91 Pierre C. Wong 5 Functional Evaluation of the Heart��������������������������������������������������������������������������� 137 Benjamin W. Eidem 6 Systemic and Pulmonary Venous Anomalies ����������������������������������������������������������� 167 Theresa Ann Tacy and Shiraz Arif Maskatia 7 Atrial Septal Defects and Atrial Anomalies ������������������������������������������������������������� 203 Louis I. Bezold III and John P. Kovalchin 8 Atrioventricular Septal Defects��������������������������������������������������������������������������������� 233 Wanda C. Miller-Hance 9 Mitral and Tricuspid Valve Anomalies��������������������������������������������������������������������� 275 John M. Simpson and Paraskevi Theocharis 10 Ventricular Septal Defects����������������������������������������������������������������������������������������� 331 Grace C. Kung and Pierre C. Wong 11 Single Ventricle����������������������������������������������������������������������������������������������������������� 357 Pierre C. Wong 12 Cardiac Malposition and Heterotaxy����������������������������������������������������������������������� 397 Pierre C. Wong and Wanda C. Miller-Hance 13 Outflow Tract Anomalies������������������������������������������������������������������������������������������� 425 Nadine Choueiter, Roque Ventura, and Leo Lopez 14 Conotruncal Anomalies ��������������������������������������������������������������������������������������������� 453 Laura M. Mercer-Rosa and Meryl S. Cohen 15 Transposition Complexes������������������������������������������������������������������������������������������� 481 Aarti H. Bhat and Brian D. Soriano 16 Great Artery and Vascular Anomalies ��������������������������������������������������������������������� 525 Wanda C. Miller-Hance

xi

xii

17 Congenital Coronary Artery Anomalies������������������������������������������������������������������� 571 Peter Frommelt 18 Intraoperative and Postoperative Applications������������������������������������������������������� 585 Wanda C. Miller-Hance and Annette Vegas 19 Other Applications, Including the Critical Care Setting����������������������������������������� 609 Pei-Ni Jone and Adel Younoszai 20 Applications for Non-Congenital Heart Disease in Pediatric Patients������������������� 635 Richard M. Friesen and Luciana T. Young 21 Applications in the Cardiac Catheterization and Electrophysiology Laboratories ��������������������������������������������������������������������������������������������������������������� 673 Peter R. Koenig and Paul Tannous 22 Congenital Heart Disease in the Adult ��������������������������������������������������������������������� 695 Jeannette Lin, George Lui, and Jamil Aboulhosn 23 Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease��������������������������������������������������������������������������������������������������������������� 717 Pierre C. Wong and Gerald R. Marx 24 Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease ����������������������������������������������������� 757 Vivian W. Cui and David A. Roberson Index������������������������������������������������������������������������������������������������������������������������������������� 799

Contents

Contributors

Jamil  Aboulhosn Ahmanson/UCLA Adult Congenital Heart Center, Streisand/American Heart Association Endowed Chair, Divisions of Cardiology and Pediatric Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA Nancy A. Ayers  Department of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Texas Children’s Hospital, Houston, TX, USA Louis I. Bezold III  University of Kentucky College of Medicine, Lexington, KY, USA Joint Pediatric Heart Care Program, Kentucky Children’s Hospital, Lexington, KY, USA Aarti H. Bhat  Division of Pediatric Cardiology, Seattle Children’s Hospital and University of Washington, Seattle, WA, USA Michael Brook  Pediatric Heart Center, University of California-San Francisco, San Francisco, USA Nadine Choueiter  The Pediatric Heart Center, Children’s Hospital at Montefiore, New York, NY, USA Meryl S. Cohen  Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA Department of Pediatrics, Division of Cardiology, Children’s Hospital of Philadelphia, Philadelphia, PA, USA Vivian W. Cui  Advocate Children’s Heart Institute, Chicago, Illinois, USA Benjamin W. Eidem  Divisions of Pediatric Cardiology and Cardiovascular Diseases, College of Medicine, Mayo Clinic, Rochester, MN, USA Richard M. Friesen  Pediatric Cardiology, Children’s Hospital Colorado, Aurora, CO, USA Peter Frommelt  Division of Pediatric Cardiology, Medical College of Wisconsin, Children’s Hospital of Wisconsin, Milwaukee, WI, USA Pei-Ni  Jone Pediatric Cardiology, Children’s Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, USA Peter R. Koenig  Northwestern University Feinberg School of Medicine, Chicago, IL, USA John P. Kovalchin  The Heart Center, Nationwide Children’s Hospital, Columbus, OH, USA The Ohio State University, Columbus, OH, USA Grace C. Kung  Division of Cardiology, Heart Institute, Children’s Hospital Los Angeles, Los Angeles, CA, USA Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA Jeannette  Lin Ahmanson/UCLA Adult Congenital Heart Center, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA xiii

xiv

Leo Lopez  Betty Irene Moore Children’s Heart Center, Lucile Packard Children’s Hospital, Stanford University School of Medicine, Palo Alto, CA, USA George  Lui The Adult Congenital Heart Program at Stanford, Lucile Packard Children’s Hospital and Stanford Health Care Collaboration, Division of Cardiovascular Medicine and Pediatric Cardiology, Stanford University School of Medicine, Palo Alto, CA, USA Ravi Managuli  Affiliate Faculty, Department of Bioengineering, University of Washington, Seattle, USA Hitachi Healthcare Americas, Twinsburg, OH, USA Gerald R.  Marx  Department of Cardiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA Shiraz Arif Maskatia  Betty Irene Moore Children’s Heart Center, Lucile Packard Children’s Hospital, and Stanford University School of Medicine, Palo Alto, CA, USA Laura  M.  Mercer-Rosa Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA Department of Pediatrics, Division of Cardiology, Children’s Hospital of Philadelphia, Philadelphia, PA, USA Wanda C. Miller-Hance  Department of Anesthesiology, Perioperative and Pain Medicine, Arthur S. Keats Division of Pediatric Cardiovascular Anesthesiology, Houston, TX, USA Department of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Texas Children’s Hospital, Houston, TX, USA Texas Heart Institute, Houston, TX, USA Michael  D.  Puchalski Pediatric Cardiology, John Hopkins All Children’s Hospital, John Hopkins University, St. Petersburg, FL, USA David A. Roberson  Advocate Children’s Heart Institute, Chicago, Illinois, USA John  M.  Simpson Department of Congenital Heart Disease, Evelina London Children’s Hospital, London, UK Brian D. Soriano  Division of Pediatric Cardiology, Seattle Children’s Hospital and University of Washington, Seattle, WA, USA Theresa  Ann  Tacy  Betty Irene Moore Children’s Heart Center, Lucile Packard Children’s Hospital, and Stanford University School of Medicine, Palo Alto, CA, USA Paul Tannous  Northwestern University Feinberg School of Medicine, Chicago, IL, USA Paraskevi Theocharis  Department of Congenital Heart Disease, Evelina London Children’s Hospital, London, UK Annette  Vegas Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto General Hospital, Toronto, ON, Canada Roque Ventura  Miami Children’s Hospital, Miami, FL, USA Pierre  C.  Wong  Division of Cardiology, Heart Institute, Children’s Hospital Los Angeles, Los Angeles, CA, USA Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA Luciana T. Young  Pediatric Cardiology, Seattle Children’s Hospital, Seattle, WA, USA Adel Younoszai  Pediatric Cardiology, Children’s Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, USA

Contributors

1

Science of Ultrasound and Echocardiography Pierre C. Wong

Abbreviations 2D Two-dimensional 3D Three-dimensional CHD Congenital heart disease CW Continuous wave dB Decibel DICOM Digital Imaging and COmmunications Medicine Hz Hertz MHz Megahertz PRF Pulse repetition frequency PW Pulsed wave PZE Piezoelectric TEE Transesophageal echocardiography

in

Key Learning Objectives • Understand the physics of sound and ultrasound, including the principles of transmission of sound through various media, and the underlying concepts of reflection, refraction, scattering, absorption • Understand the basic principles of ultrasound transducer design and function • Understand how echocardiographic images are formed • Understand the important factors that affect spatial and temporal resolution • Understand the fundamental principles of Doppler echocardiography, the different modes of Doppler evaluation (including spectral and color flow Doppler), and the role P. C. Wong (*) Division of Cardiology, Heart Institute, Children’s Hospital Los Angeles, Los Angeles, CA, USA Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA e-mail: [email protected]

use of Doppler for hemodynamic and myocardial function assessment • Recognize the key components of the echocardiography machine • Know and recognize the type of echocardiographic artifacts that might be encountered • Understand the principles of the DICOM (Digital Imaging and COmmunications in Medicine) standard

Introduction This is a textbook on transesophageal echocardiography (TEE), specifically TEE for the evaluation of pediatric and congenital heart disease (CHD). But what is TEE? It is a specialized form of echocardiography, which is itself a specialized form of ultrasonography focusing upon the heart and related vascular structures. Thus, anyone seeking to achieve proficiency in echocardiography and TEE needs to have a solid understanding of the underlying science of ultrasound, particularly its strengths and weaknesses as applied to the evaluation of the cardiovascular system. This chapter reviews the physics and instrumentation of ultrasound and echocardiography. It is not intended to be an exhaustive review of the subject—that would require a separate textbook, and a number of excellent and comprehensive references have already been written on the subject [1–5]. Rather, its purpose is to provide an overview of the science of ultrasound, focusing on aspects that apply especially to modern day echocardiography and TEE technology, and touching upon details pertinent to the echocardiographic evaluation of CHD. This chapter is divided into six major sections: (1) Physics of Sound and Ultrasound; (2) Important Principles of Echocardiographic Image Formation; (3) Doppler Echocardiography; (4) Overview of the Echocardiography Machine; (5) Artifacts; (6) Digital Imaging and DICOM.  While knowledge of the material in earlier sections aids in the comprehension of later sections, readers should feel free to peruse the chapter in whatever order they find most useful.

© Springer Nature Switzerland AG 2021 P. C. Wong, W. C. Miller-Hance (eds.), Transesophageal Echocardiography for Pediatric and Congenital Heart Disease, https://doi.org/10.1007/978-3-030-57193-1_1

1

2

P. C. Wong

Background The concept of utilizing sound for the purposes of location and imaging has its origins in nature. It is well known that bats use ultrasound (high frequency sound above the range of human hearing) in order to fly and locate their prey, even in complete darkness. This capability, which evolved over millions of years, is known as “echolocation”. Dolphins, porpoises and toothed whales are also known to utilize ultrasound underwater for echolocation. In World War I, SONAR (SOund NAvigation and Ranging) was developed, in which piezoelectric materials were formulated as senders and receivers of high frequency sound waves, and these were employed to detect enemy submarines underwater. This technology was further developed and put to good use in World War II, and is still widely utilized today in both the commercial and military nautical industry. Medical diagnostic ultrasound was first developed in the 1940s–1950s. Over the past 60–70 years, rapid advancements in computing and probe miniaturization technology have made possible the development of high resolution, real-time twodimensional (2D) ultrasonography, leading to the ability to define precisely the anatomy and physiology of the heart by echocardiography [6]. Regardless of whether it is used in bats, SONAR, or medical imaging, the basic principle (known as the pulse-echo principle) remains the same. Sound waves of known frequency are generated and sent (pulsed) in a specific direction, with the intention that a target object (or objects) will reflect some or all of the sound waves back to the source (Fig. 1.1). The sender then “listens” for the returning signals

Transmitter/ Receiver

Reflected wave

Transmitted wave Dis

Object/

tan

ce

Reflector

Fig. 1.1  Pulse-echo principle. A pulse of sound of known frequency is generated and emitted in a known direction. The echoes returning from an object can be used to derive information regarding the object, including distance, size, etc.

(echoes) from the target object; these returning echoes carry important information that can be used to abstract details about the object, including distance, image, size, movement, etc. The following sections discuss the physical process in which ultrasound, specifically through the use of the pulse-­echo principle, is utilized to obtain detailed information for medical diagnostic imaging—particularly in regard to noninvasive cardiac evaluation by echocardiography and TEE.

Physics of Sound and Ultrasound Sound: Definition and Properties Sound is a form of mechanical energy that requires a physical medium for transmission; this medium must contain molecules (such as air, water, etc.) that are used to propagate the sound. Unlike electromagnetic waves, which do not require a medium for propagation, sound cannot be transmitted in a vacuum. A sound wave is created when a discrete source—a vibrating or oscillating object—pushes and pulls adjacent molecules, causing them in turn to vibrate; this vibration spreads to adjacent molecules, and thus a disturbance is propagated away from the source in the form of a longitudinal wave characterized by a series of back and forth vibrations of molecules (Fig.  1.2). The direction of this back and forth vibration is parallel to the direction of wave propagation. The wave that is created represents a series of compressions, when the molecules are pushed together, and rarefactions, when the molecules are pulled apart (Fig. 1.2). If one could measure the instantaneous pressure at different points, the regions of compression, in which there is a greater density of molecules, would have a higher pressure than normal, and the regions of rarefaction (with a lesser density) would have a lower pressure than normal. Plotting a graph of pressure vs. distance from the source (along the line of propagation) would produce a curve in the shape of a sine wave (Fig.  1.2). The importance of this sine wave is that, like any wave, it has certain properties that can be used to describe it. The peak of one wave to the next peak (or valley to valley) represents one full wave or one complete cycle or period; the number of times per second that the cycle is repeated is termed the frequency, and the unit to measure this is cycles per second, or Hertz (Hz). This frequency is determined by the number of oscillations per second made by the sound source. The physical distance between two peaks (or valleys) is termed the wavelength and often designated by the symbol λ. This is the distance the sound wave travels

1  Science of Ultrasound and Echocardiography Fig. 1.2  Generation of a sound wave. A vibrating source (in this case, a tuning fork) causes adjacent air molecules to vibrate in a back-and-forth direction. This oscillating motion propagates away from the source in a series of compressions and rarefactions; when the air pressure at any one point is plotted as a function of time, a sine wave is obtained with a wavelength (λ) and pressure amplitude (P). Shorter wavelengths are associated with higher wave frequencies; longer wavelengths with lower frequencies. This example shows sound propagation in air, but the same principles apply in water or in the soft tissue of the human body

3 Direction of propagation

Compression

Rarefaction

Compression

Rarefaction Maximum pressure

Amplitude (P)

Wavelength (λ) 1 cycle or period

Higher frequency

Lower frequency

Shorter wavelength

Longer wavelength

in one complete cycle. The importance here is that frequency and wavelength are inversely related, and their magnitude depends upon the speed of sound in the medium (Table  1.1a). The equation relating these three variables is given as follows:



c f

Minimum pressure

(1.1)

λ = wavelength c = speed of sound in the medium f = frequency in cycles/sec The speed of sound varies depending upon the medium: the denser the medium, the faster the speed of propagation. In biological systems, the speed of sound exhibits wide variation: it is lowest in the lungs, which are air-filled structures (about 600  m/s), and highest in bone (about 4080  m/s) (Table 1.1A). In the soft tissues, the average speed of sound is about 1540  m/s, and this is the number generally used

when calibrating the range-measuring circuits of most diagnostic ultrasound instrumentation [1]. As will be shown throughout this chapter, the speed of sound in the human body plays an important role in a number of considerations related to echocardiography. The importance of Eq. 1.1 is that, by knowing the speed of sound in the medium, the wavelength can be calculated for a given sound frequency, and vice-versa. The range of sound frequencies audible by the human ear is between 20 and 20,000  Hz. However, if sound waves of these frequencies were transmitted in the body, the corresponding wavelengths would be far too large for use in the medical field. For diagnostic medical imaging, adequate resolution is possible only when the wavelength of the sound wave is comparable to the size of the smallest objects being imaged [7, 8]. For echocardiography, this translates to millimeters or less, which means that sound frequencies in the millions of Hertz (megahertz, or MHz) must be used. Note that these frequencies are extremely high, several orders of magnitude beyond the range of human hearing—hence the term ultrasound.

4

P. C. Wong

Table 1.1  Physical properties of sound for various tissues in the Human body (For each table, measurements are listed from lowest to highest value) A. Speed of sound Material Lung Fat Liver Blood Kidney Muscle Lens of eye Skull bone B. Acoustic impedance Tissue Air Lung Water Brain Blood Liver Kidney Human soft tissue, mean Muscle Skull bone

Speed of sound (meters/second) 600 1460 1555 1560 1565 1600 1620 4080 Acoustic impedance (Rayls × 10−4) 0.0004 0.18 1.5 1.55 1.61 1.65 1.62 1.63 1.71 7.8

C. Attenuation coefficient Tissue Attenuation coefficient (dB/cm) Water 0.0022 Blood 0.18 Fat 0.6 Brain 0.85 Liver 0.9 Kidney 1.0 Muscle 1.2 Skull bone 20 Lung 40



I

P2 2c

(1.2)

I = intensity P = acoustic pressure in Pascals 𝜌 = density of the medium c = speed of sound in the medium Intensity is the parameter used to characterize the spatial distribution of ultrasound energy. As noted, it describes the amount of ultrasonic power per unit area (given in watts/ square meter, or more commonly milliwatts per square centimeter), and can vary depending upon location. The difference between acoustical power and intensity can be illustrated in the following example: two beams (one focused, one unfocused) are emitted with the same acoustic power. While the unfocused beam has a more uniform distribution of energy; the focused beam will produce more concentrated energy in the area focused. Hence, the intensity is greater in that area. Intensity is also one of the parameters used to evaluate the biological effects of ultrasound. At sufficiently high intensities and long enough exposure times, ultrasound can produce a measurable effect on tissues, notably in the form of heating and cavitation (tiny bubbles from dissolved gases in the medium) [1]. The subject of the biological effects of ultrasound on human tissue is beyond the scope of this chapter. Suffice it to say that while no known ill effects have been noted from the intensity levels and scan times commonly used in diagnostic medical ultrasound, it is still important to be mindful of the remote possibility—particularly if equipment manufacturers were to increase output intensities to improve imaging [3, 9]. For medical imaging, a standard method for quantifying intensities or power levels is by using the decibel (dB) system. Instead of providing an absolute number, this method produces a value that represents a relative change (or ratio) between two amplitudes or two intensities. Using two echo signal intensities I1 and I2 or two echo signal amplitudes A1 and A2 (I1 and A1 representing the reference signal), the signal level in dB is calculated as follows:

Echocardiography generally utilizes frequencies between 1 and 15 MHz, which by Eq. 1.1 yields a wavelength between 0.1 mm (15 MHz) and 1.54 mm (1 MHz). The higher the frequency, the smaller the wavelength, and the better the spatial resolution. The other important property of a sound wave is its amplitude, which describes the strength of the wave, or maximum pressure elevation from baseline (Fig. 1.2). This I A Signal level 10 log 2 or Signal level 20 log 2 (1.3) = = corresponds to the “loudness” of the sound. This property, I1 A1 also known as acoustic pressure, is measured in Pascals (P). The amplitude of the sound represents the energy associated with the sound wave: the more the energy, the “louder” the sound and the greater the amplitude. Another parameter used to express the “loudness” of the sound is known as intensity. This term is used to describe the energy flowing a cross-sectional area per second and is proportional to the square of acoustic pressure, as noted by the equation:

It is meaningless to use a dB level as an absolute value. Rather, the dB notation provides a value obtained when comparing a particular intensity or amplitude to a reference value. In diagnostic medical ultrasound, the transmitted signal generally serves as the reference value. Note that the dB represents a logarithmic scale, therefore an intensity change of +3  dB represents a doubling of intensity, and −3  dB a halving of intensity. The dB system is used to express output

1  Science of Ultrasound and Echocardiography

power, dynamic range, or ultrasonic attenuation in tissue (see below). It represents a simpler, more compact method to express large differences in power levels or intensity, and will be used throughout the remainder of this chapter.

Reflection: The Key to Ultrasonic Imaging

5

Tissue 1 Impedance Z 1

Incident wave Amplitude P i

Reflected wave Amplitude Pr

Interface

As an ultrasound wave propagates through the body, several different interactions are possible as it encounters the various tissues interfaces. These interactions, analogous to those occurring with light waves, include: (a) continued transmission, (b) reflection, (c) refraction, (d) absorption. Of these, reflection is the key interaction that makes possible the generation of ultrasonographic/echocardiographic information. As mentioned above, diagnostic medical ultrasound consists of emitting sound pulses in a known direction, and then collecting and processing the returning echo signals—that is, the signals that have been reflected from the various internal structures in the body (in the case of echocardiography, the heart, blood and vascular structures). The differences in the strength of the returning signals enable the ultrasound machine to build an image of the various tissues, as well as the tissue-tissue and tissue-blood interfaces, and this forms the basis of echocardiographic imaging. What determines how echo signals are reflected, and the strength of these signals? A fundamental factor is acoustic impedance, an intrinsic property of tissue that characterizes its capacity for sound transmission. The acoustic impedance of a tissue is directly proportional to its underlying density—the denser the tissue, the higher the acoustic impedance. Each type of tissue has a different acoustic impedance: air has an extremely low impedance, bone has a very high impedance, and the various soft tissues have impedances that differ from each other but vary within a much narrower range (Table 1.1B). At a tissue interface, the degree of reflection vs. transmission of an incident sound wave depends upon the relative difference in acoustic impedance between the two tissues—that is, the degree of impedance matching. When there is a small impedance mismatch, most of the sound energy is transmitted, and only a small amount is reflected and returns to the source (transducer) to be used as imaging information (Fig. 1.3). As the transmitted energy continues further, some is reflected in a similar manner at more distant interfaces, yielding imaging information from deeper structures. This process continues along the length of the ultrasound beam. In this manner, ultrasonic information is progressively obtained, and imaging is possible to significant depths because the acoustic impedance differences are small for most soft tissue-soft tissue interfaces. However, if a significant impedance mismatch exists between two tissues, then virtually all sound is reflected, and very little transmitted. Almost no usable information is available beyond the interface (a phenomenon

Tissue 2 Impedance Z 2

Transmitted wave

Fig. 1.3  Specular reflection. When an incident sound wave of amplitude Pi encounters a smooth interface perpendicular to the direction of propagation, some is reflected (amplitude Pr) and the remainder transmitted. The degree of transmission vs. reflection depends upon the relative differences in acoustic impedance between the two tissues (Z1 and Z2)—the greater the impedance mismatch, the greater the amount of sound reflected

known as “acoustic shadowing”). This is the reason that lung interferes with ultrasonic imaging: it is not that ultrasound cannot propagate through lung, it is that the impedance mismatch is so great between lung and soft tissue that virtually all ultrasound energy is reflected. It is also the reason that ultrasonic gel is used with transthoracic imaging: to improve the acoustic coupling (impedance matching) between the transducer and the chest wall. Acoustic impedance matching is important whenever a sound wave encounters an interface between two tissues, and it is particularly important for those interfaces that are much larger than the size of the ultrasound wavelength. When such interfaces are large and smooth, they are termed specular reflectors and they behave like a large acoustic mirror (speculum = mirror in Latin). If there is a sizable impedance mismatch, incident ultrasound beams will undergo a great deal of reflection. If the incident beam is directed perpendicular to the surface, the reflected sound waves return to the transducer as a well-defined, redirected beam (echo), leading to a very bright appearance on the display screen (Fig. 1.4). If the incident ultrasound beam strikes the specular reflector at an angle, the reflected portion will be directed at an angle θr which is equal to the incident angle θi but in the opposite direction. The remainder of the incident beam that is transmitted can be “bent” or refracted, with the amount of refraction depending upon the difference between the speed of sound between the two tissues, as given by Snell’s Law (Fig. 1.5). The greater the difference in the speed of sound between the two tissues, the greater the degree of refraction. Again, this is analogous to the behavior of light waves. In general, refraction is not a major problem with diagnostic ultrasound because there is little variation in the speed of

6

P. C. Wong

b

a

Fig. 1.4  Example of a large specular reflector (diaphragm) and acoustic scattering produced by myocardium (a) and liver parenchyma (b). Note that the echoes from the specular reflector have the largest amplitude (brightness) when the surface is perpendicular to the angle of

θi

θr

Interface

θt Expected

Snell’s Law sin sin

t i

=

c2 c1

= incident beam angle = transmitted beam angle c 1 = speed of sound (incident beam side) c 2 = speed of sound (transmitted beam side) i

t

Fig. 1.5  Refraction and Snell’s law. When the incident sound wave encounters a large specular reflector at a nonperpendicular angle 𝜃i (𝜃i refers to the angle as measured from the perpendicular axis), the reflected beam travels off at an equivalent angle 𝜃r. The transmitted wave undergoes refraction or “bending”. The amount of refraction can be predicted by Snell’s law, which is itself based upon the difference in the speed of sound between the two tissues. The greater the difference, the greater the degree of refraction

insonation. In (a) the myocardium has the characteristic heterogeneous 2D appearance produced by natural acoustic reflections and interference patterns (scattering) from its various components, also known as “speckle”

sound among the soft tissues in the human body. However in certain situations, refraction can lead to image errors; this can be seen in the setting of interfaces between fat and soft tissue. What if the large surface is not smooth, but rough? In this case the uneven surface causes incident energy to be reflected in a number of different directions. This is called diffuse reflection (Fig.  1.6). Such reflections can cause a loss of beam coherence and a weaker echo returning to the transducer. Some organ boundaries, as well as the walls of the heart chambers (irregular endocardial surfaces), fall within this category. At first glance, it would appear that that these signals, along with the nonperpendicular signals to a specular reflector (whether reflected at an angle or refracted) would not be as useful for imaging because they are not directed back to the transducer. However, in practice, even these off-angle specular and diffuse reflectors are useful for ultrasonic imaging due to the range to different transducer positions that can be utilized. In addition, divergences of the ultrasound beam can result in sound waves that will be reflected back to the transducer [10]. In fact, echoes from diffuse reflectors, while weaker, can be useful because of the fact that they are not as sensitive to the orientation of the transducer. The information from diffuse and specular reflectors is most useful at the boundaries of objects and organs, for example along the diaphragm or pericardium. However, an even more important type of reflection accounts for much of the useful diagnostic information in ultrasonic imaging, including echocardiography. This type of reflection is called acoustic scattering, also known as nonspecular reflection. It refers to reflections from objects the size of the ultrasound

1  Science of Ultrasound and Echocardiography

7

positions (Fig.  1.4b). Changes in scattering amplitude will result in brightness changes on the ultrasound image on the display, giving rise to the terms hyperechoic (increased scattering, brighter) and hypoechoic (decreased scattering, darker), and anechoic (no scattering, black appearance). At the opposite extreme from the large specular reflectors are the very small reflectors whose dimensions are much less than the ultrasonic wavelength. Such reflectors also produce scattering, and are termed Rayleigh scatterers. This category most notably includes red blood cells, and the scattering that results from these gives rise to the echo signals from blood for Doppler and color flow imaging. Scattering from Rayleigh scatterers increases exponentially (to the fourth power) as frequency is increased.

Attenuation and Ultrasonic Imaging

Fig. 1.6  Diffuse reflector. An incident beam striking a rough, uneven surface results in lower amplitude reflected waves that travel away from the reflector in multiple directions. This type of echo is not as dependent upon interface orientation as a specular reflector

wavelength or smaller. The parenchyma of most organs, including the heart, contains a number of objects (reflectors) of this size. The signals from these reflectors return to the transducer through multiple pathways. The sound from such reflectors is no longer a coherent beam; it is instead the sum of a number of component waves that produces a complex pattern of constructive and destructive interference. This interference pattern is known as “speckle” and provides the characteristic ultrasonic appearance of complex tissue such as myocardium (Fig.  1.4a) [8]. These signals tend to be weaker, and echo signal strength varies depending upon the degree of scattering. The degree of scattering is primarily based upon: (a) number of scatterers per unit volume; (b) acoustic impedance changes at the scatterer interfaces; (c) size of the scatterer—increased size produces increased scattering; (d) ultrasonic frequency—scattering increases with increasing frequency/decreasing wavelength [1]. The last point is important, because it contrasts to specular reflection, which is frequency independent. Therefore, it is possible to enhance scattering selectively over specular reflection by using higher ultrasound frequencies. Also, because of the fact that scattering occurs in multiple directions, the incident beam angle/direction is not as important as with specular reflectors. This is why organ parenchyma (such as liver) can be readily viewed from a number of different transducer

As ultrasound travels through tissue, the amplitude and intensity of the signal decreases as a function of distance. This is known as attenuation, and is due to several mechanisms. The first mechanism is one in which acoustic energy is converted into another form of energy, principally heat; this is known as absorption. The second mechanism involves redirection of beam energy, by a number of different processes including scattering, reflection, refraction, diffraction and divergence (the latter two processes result in a spreading of the sound beam). Scattering and reflection (and also refraction) were discussed above; while both play an essential role in diagnostic medical imaging, each process also reduces the intensity of ultrasound energy transmitted distally, thereby attenuating the transmitted signal. The third mechanism involves interaction between sound waves, known as interference. Wave interference occurs when two waves meet. It can be constructive or destructive, depending upon whether the two waves are in phase or out of phase. When in phase (constructive), an additive effect is produced, increasing amplitude; when out of phase (destructive), the waves can effectively cancel each other out. The degree of attenuation can be given as an attenuation coefficient (α) in decibels per centimeter (dB/cm), representing the reduction in signal amplitude or intensity as a function of distance. The amount of attenuation, as measured in decibels, can be calculated by the equation: Attenuation (dB) = α × distance (cm). The attenuation coefficient varies with the type of medium through which the ultrasound is transmitted (Table 1.1C). As can be seen, there is little attenuation in blood, but significant attenuation in bone. Attenuation in muscle is twice that of other tissues such as fat. Another important determinant of attenuation is the frequency of the ultrasound beam. In most cases, attenuation increases approximately linearly with frequency: the higher the frequency, the greater the attenuation (Fig. 1.7).

8

P. C. Wong

Lower frequency

Higher frequency Distance from transducer

Fig. 1.7  Attenuation of ultrasound in parenchyma. As an ultrasound pulse travels through tissue, its amplitude and intensity decrease as a function of distance from the transducer. This is known as attenuation. Higher frequency sound waves are attenuated much more rapidly than lower frequencies

However, as will be seen with much of ultrasound, there are tradeoffs. In this particular case, the tradeoff is depth. While higher frequencies provide enhanced spatial resolution, in soft tissue they are attenuated much more rapidly than lower frequencies, hence the depth of penetration is much less, and so the higher frequencies are not as useful for visualizing deeper structures. This is why higher frequency, higher resolution transthoracic imaging is much more feasible in pediatric compared to adult patients. It is also one of the reasons that TEE provides superior imaging compared to transthoracic imaging in larger patients: the proximity of the esophagus to the heart significantly reduces attenuation and enables the use of higher frequency ultrasonic imaging.

I mportant Principles of Echocardiographic Image Formation At first glance, the basic premise behind 2D imaging in echocardiography seems relatively straightforward. Using the pulse-echo principle discussed above, an ultrasound pulse is emitted as a well-directed beam, and reflected echo signals are collected from the beam line. If this is continued while the ultrasound beam is swept in an arc (sector), a 2D image can be constructed, using echo arrival times and beam axis location to determine the precise location of reflectors within the sector (Fig. 1.8). However, the actual process by which reflected ultrasound signals are converted into real-time, 2D echocardiographic images is deceptively complex, requiring sophisticated and technologically intricate hardware, along with highly advanced and powerful computing and digital signal pro-

cessing capabilities. A number of different steps are involved: generation of high-quality and well-directed ultrasound pulses, reception and digitization of the returning signals, multilayered digital signal processing, and conversion of these signals to a real-time 2D image of sufficient medical diagnostic quality (while at the same allowing operator manipulation and pre/post processing of the images). Moreover, for echocardiography and TEE the same process must be repeated rapidly and continuously in order to display the real-time motion of the heart. The sections that follow discuss the process by which ultrasound pulse generation leads to image formation, specifically as pertains to echocardiography. For simplicity’s sake, the discussion will first cover basic ultrasound beam forming principles utilizing single element transducers. These principles will then be applied to array transducers, which form the basis for modern day echocardiography, including TEE.

Transducers The first step in ultrasound imaging requires the creation and transmission of an appropriate sound wave; this is accomplished by the use of a transducer. Technically, the term transducer refers to any device that is used to convert one form of energy into another. The ultrasonic transducer converts electrical energy to mechanical (acoustic) energy in the form of sound waves that are then transmitted into the medium. When reflected sound waves return, the reverse process occurs: the transducer receives the acoustic energy and converts it into electrical signals for processing. Transducers in medical ultrasound achieve this conversion by the piezoelectric (PZE) effect. The PZE effect is a special property seen with certain types of crystals (quartz, ceramics, etc.). When an electrical signal is applied to such a crystal, it vibrates at a natural resonant frequency, sending a sound wave into the medium. Conversely, acoustic energy received by the crystal produces mechanical pressure or stress, which then causes the crystal to generate an electrical charge that can be amplified, yielding a useful electrical signal. Thus, PZE transducers can serve as both detectors and transmitters of ultrasound. As noted previously, the signals must be appropriate for imaging of tissues in the human body—wavelengths must be no more than 1–2 mm, which means sound frequencies must be in the millions of Hertz. While several PZE crystals found in nature (e.g. quartz) have been used for ultrasonography, most present-day ultrasound transducers utilize man-made PZE ceramic (such as lead zirconate titanate, also known as PZT) and composite ceramic elements. When excited, the PZE elements can produce the very high frequencies required for diagnostic medical imaging. A PZE transducer operates best at its natural resonance frequency, which corresponds to the crystal (element) thick-

1  Science of Ultrasound and Echocardiography

Fig. 1.8  Production of an ultrasound (echocardiographic) image. A pulse of ultrasound is transmitted in a well-defined beam, and the transducer “listens” while echoes are received from the same beam path. These echoes appear as dots (brightness) corresponding to signal ampli-

ness; however, newer composite elements have wide frequency bandwidths and can operate at different frequencies, enabling generation of multiple frequencies from one transducer. In these instances, the native frequency, which usually represents the midpoint of the frequency distribution, is termed the “center” or “central carrier” frequency. More recently, single crystal materials with homogeneous solid-­ state technology have been developed; the advantage of these newer transducers is that have a wider bandwidth and lower power consumption, resulting in increased ultrasound penetration and resolution. Doppler sensitivity is also increased [11]. However, a transducer is not simply a housing surrounding a PZE element or collection of elements (see arrays below). While the PZE element serves as the most important component of an ultrasound transducer, a number of other essential components also reside in the transducer. These include backing (damping) material, electrodes, an insulating cover, housing, matching layer, and acoustic lens (in some transducers) (Fig. 1.9). The matching layer, which covers and attaches to the PZE element, is very important because of the significant impedance mismatch that exists between the PZE element and skin or esophagus. The matching layer contains an acoustic impedance intermediate between the two surfaces; this helps to match impedances from one surface to the other, allowing for efficient sound transmission between transducer element and soft tissue. In some transducers, multiple matching layers are used to facilitate transmission of a range of ultrasound frequencies. Also,

9

tude. During 2D imaging, the beam is swept across a sector, and displaying all the beams along this sector results in a 2D (B-mode) image. In this example, a transesophageal transducer is shown, but the same process occurs with transthoracic echocardiography

Housing and insulator

Backing material

Piezoelectric element

Lens/face plate

Connector Electrical leads

Matching layer(s) Front and rear electrodes

Fig. 1.9  Diagram of a single element transducer. The various components of the transducer are seen. In this example, there is a large, single piezoelectric crystal. For a phased array transducer, instead of a large single element, multiple elements would be laid in a single row, each with its own electrical connector. However, the other parts of the transducer would be analogous to the single element transducer

newer composite PZE elements have acoustic impedances much closer to that of soft tissue. The backing (damping) material also serves an important role. Pulse-echo ultrasound involves the transmission of a short pulse of sound, following by a period in which the transducer “listens” for the returning echoes. As it turns out, for ultrasound imaging the transducer spends only a tiny fraction of time actually transmitting sound—this is known as the duty factor, and typically comprises less than 1% of

10

P. C. Wong

Amount of signal

Frequency

Amount of signal

Frequency

Fig. 1.10  Spatial pulse length. The top pulse has undergone less damping; therefore, it has a longer duration, or spatial pulse length, and a purer “tone” with most of the sound at or near a certain frequency.

Contrast this with the bottom pulse, which has undergone excellent damping that reduces the spatial pulse length. This type of pulse is characterized by a large frequency bandwidth

the total time. The rest of the time is spent listening for returning echoes. For this to occur, the transducer can emit only a very short pulse of acoustic energy, usually only a small number of cycles in length. To produce these, short bursts of electrical energy cause the PZE element to vibrate or “ring”, which generates the acoustic pulse. The length of the pulse train, also known as pulse duration or spatial pulse length, is truncated by damping the duration of the vibration as quickly as possible, and the backing material plays an important role here. An important point regarding pulse duration is that short pulses are desirable to optimize axial resolution, as will be discussed below. The typical pulse length is 1–3 cycles in length. Of note, a shorter pulse is a less “pure” tone, and contains a wider range of frequencies, also known as having a broader bandwidth (Fig. 1.10). This range of frequencies encompasses the labeled operating (center) frequency, which represents the midpoint of the frequency distribution. Wide bandwidth associated with short pulse duration is more desirable for imaging applications; narrower frequency bandwidth associated with longer pulse duration is more useful for pulsed Doppler applications.

ultrasound beam becomes considerably more important. Diagnostic medical ultrasound transducers are designed to direct ultrasound pulses in a specific direction. A single element ultrasound source of large dimensions (for example, a transducer face much larger than the wavelength of sound emanating from it) can produce equally spaced, linear wavefronts (Fig.  1.11b) also known as planar wavefronts [12]. Conceptually, these planar wavefronts can be described as a collection of multiple individual point sources, also known as Huygen sources, and the wavelets arising from these sources are known as Huygen wavelets [1]. Interference among wavelets results in the large planar waveform (Fig. 1.11c). One of the important aspects of ultrasound beam formation concerns the geometry of the beam and its impact upon imaging. With a single element, unfocused ultrasound transducer, the individual wavelets from a transducer form a near parallel beam wave front, as noted in Fig. 1.11c. Two important zones develop in this beam. The first distance is the near field, or Fresnel zone. This area is characterized by many regions of constructive and destructive interference, leading to fluctuations in intensity. In this zone, the beam remains well collimated for a certain distance, and even narrows slightly (Fig.  1.12). Beyond the near field, the beam diverges, and some energy escapes along the periphery of the beam; this is known as the far field or Fraunhofer zone (Fig. 1.12). Fresnel (near-field) length is directly proportional to aperture of the transducer element and inversely proportional to transducer frequency, as given by the equation:

Transducer Beam Formation and Geometry When sound waves originate from a single, small point source whose size is similar to the wavelengths it produces (such as a bell), the waves radiate outward in all directions (Fig.  1.11a). However, this results in an unfocused signal, unsuitable for medical imaging in which a directed, focused

1  Science of Ultrasound and Echocardiography

a

11

b Single Small Element

c Single Large Element

Fig. 1.11  Sound wave geometry. (a) A single small element has a size similar to the wavelength it produces. Sound from this element radiates in all directions. (b) The single element is much larger than the sound wavelengths it produces, resulting in equally spaced, planar wavefronts.

These planar wavefronts can be thought of as a collection of individual point sources, each with its own wavelet. (c) These are known as Huygen wavelets

Fig. 1.12  Sound beam pattern from a single element, unfocused transducer. The near field is known as the Fresnel zone, the far field is known as the Fraunhofer zone. Note that the sound beam is well collimated in the near field and diverges in the far field



DFresnel 

Single Large Element

Near Field Fresnel zone Far Field Fraunhofer zone

d2 4

(1.4)

DFresnel = Fresnel (near field) length d = diameter, or aperture, of the transducer λ = ultrasound wavelength The importance of these two zones lies in the fact that lateral resolution is best before divergence of the beam, hence the best imaging and spatial detail are obtained within the Fresnel zone, or near-field. From Eq.  1.4, it becomes apparent that a larger transducer diameter as well as higher frequencies (leading to shorter wavelengths) will increase the near-field length and maximize image quality (Fig. 1.13). These have an immediate impact on lateral resolution. The above considerations of frequency and transducer diameter were discussed in the context of a single element, unfocused transducer. It is clear that—even without beam focusing—it is desirable to perform imaging in the near field. However, there is another very important aspect of beam geometry: that of focusing the beam, which has the effect of narrowing the beam profile. The narrowest portion of this beam is the focal distance, and the focal zone corresponds to the region over which the width of the beam is less than two

times the beam width at the focal distance (Fig. 1.14). This is the area in which ultrasound intensity is highest, and also where the lateral resolution is best; whenever possible, imaging of key structures should be performed within this zone. As will be discussed below, a focused, narrow beam is desirable for 2D imaging. With single element transducers, this is performed by utilizing a curved PZE element or acoustic lens to focus and narrow the beam width; however, in such cases the focal distance is generally fixed. Nonetheless, in the past these focused, single element transducers formed the basis of the early mechanical sector echocardiography platforms. Obviously, the ability to change a transmit focus dynamically would enhance the imaging capabilities of an ultrasound platform. The advent of array technology marked a significant advance in the field of echocardiography: variable beam focusing and beam shaping became a reality, adding a great deal of flexibility and power to echocardiographic imaging. Array technology is discussed in the next section.

Arrays The foundation of current ultrasound transducer technology, particularly that used in echocardiography, is based upon the concept of transducer arrays. Rather than a single element,

12 Fig. 1.13  Effect of transducer frequency and diameter on near field length. (a) Both transducers have the same frequency, but the larger diameter transducer has a longer near-field length, and less beam divergence. (b) Both transducers have the same diameter, but the transducer with the higher frequency has the longer near-field length and less beam divergence

P. C. Wong

a

Near Field

Near Field

b High frequency

Near Field

Low frequency

Near Field

Focal distance

Focal zone

Fig. 1.14  Beam pattern for a focused transducer. The beam is narrowest at the focal distance; hence the best lateral resolution is within the focal zone. Focusing can either be done externally (e.g. acoustic lens)

for a single element transducer or, in the case of an array transducer, focusing can be performed electronically and dynamically

an array consists of a group of closely spaced PZE elements, each with its own electrical connection to the ultrasound machine. This enables the array elements to be excited individually or in groups. The resultant sound beam emitted by the transducer results from a summation of the sound beams produced by the individual elements. The wave from an individual element (which is quite small, often less than half a wavelength) is by itself broad and unfocused. However, when a group of elements transmits simultaneously, there is reinforcement (constructive interference) of the waves along the beam direction, and cancellation (destructive interference) of the waves in other directions, yielding a more well-­

defined, planar ultrasound beam (Fig.  1.15a). The whole concept of arrays is based upon Huygens’ principle, in which a large ultrasound beam wavefront can be divided into a large number of point sources (Huygen sources) from which small diverging waves (Huygen wavelets) merge to form a planar wavefront [1]. The resultant beam can also be focused electronically by introducing time delays to the separate elements, in a manner essentially the same as using a focusing lens or curved PZE element (Fig.  1.15b). Electronic beam steering can occur, in which beams can be swept across an imaged field without any mechanical motion in the transducer (unlike the older mechanical sector transducers).

1  Science of Ultrasound and Echocardiography

Moreover, the focal distance is not fixed but dynamic, and can be adjusted by the operator. Furthermore, multiple transmit focal zones can be utilized to increase the focal zone of an instrument, thereby improving image quality throughout the sector (however this requires extra “pulses” and can result in a lower image frame rate). Thus, the array transducer provides a tremendous amount of flexibility for imaging. There are a number of different types of arrays available Fig. 1.15  Phased array transducer. When all elements are stimulated simultaneously, the waves from the individual elements act as Huygen point sources, merging to produce a large planar wavefront (a). With an array transducer, the beam can be focused by introducing time delays to the separate elements (b), producing beam geometry analogous to that obtained by an acoustic lens

a

13

steer and focus the ultrasound beam. In this manner, timing sequence alterations allow successive beam lines to be generated (Fig.  1.16). Therefore, in phased array transducers, the beam can be electronically swept in an arc, providing a wide field of view despite the relatively small footprint. In addition, the direction of echo reception (“listening”) can be varied electronically. Returning echo signals from reflectors along each scan line are received by all the elements in the phased array; because of slightly different distances from a b

Multiple Small Elements (Phased Array)

for ultrasonic imaging (linear, curvilinear, annular), but the phased array transducer is generally the one used for 2D echocardiography. This type of array is smaller than linear and curvilinear arrays, thereby providing a smaller ­transducer “footprint” that allows the transducers to be used with the smaller windows available for transthoracic (particularly pediatric) and transesophageal imaging. The number of PZE elements in a transthoracic phased array probe generally ranges between 64 and 256 (or more) elements. One of the important distinguishing characteristics of phased array transducers is that—unlike linear and curvilinear arrays—all elements of the phased array are excited during the production of one transmitted beam line (Fig. 1.16). The direction of the beam is steered electronically by varying the timing sequence of excitation pulses; the term phasing describes the control of the timing of PZE element excitation in order to

Electronically Focused Phased Array

reflector to the individual elements, the returning signals will not be in phase and therefore electronic receive focusing must be performed to bring them back into phase to prevent destructive interference of returning signals. This is done by applying time delays to the individual element returning signals, analogous to the time delays used for transmission. In this way, the signals from the individual elements will be in phase when summed together to produce a single signal for each reflector. Receive focusing is adjusted dynamically and automatically by the ultrasound machine in order to compensate for different reflector depths. An essential component of modern ultrasound systems that use array transducers is the beam former. This component of the system provides pulse-delay sequences to individual elements to achieve transmit focusing. In addition, it controls beam direction and dynamic focusing of received

14

P. C. Wong

Linear Array

123

Phased Array

234

Fig. 1.16  Linear vs. phased array transducer. In the linear array, small groups of elements are stimulated to produce one beam line. Once the returning signals are received, a second adjacent group of elements is stimulated to produce the second beam line. This process continues sequentially down the length of the transducer. Not all elements are

stimulated at one time. In contrast, the phased array transducer has a smaller footprint, and all elements are utilized to produce and steer every beam electronically. By varying the timing of pulses to the elements, sequential beam lines can be generated and swept in an arc

echoes, as well as other signal processing. It is located on the ultrasound system and electronically connected to the individual transducer PZE elements. Traditionally, beam formers have been analog, but ultrasound manufacturers now utilize digital beam formers. A newer type of array, the matrix array, has been developed for real-time three-dimensional (3D) transthoracic and TEE. This consists of more than 2500–3000 elements laid out in a 2D square array slightly larger than 50 × 50 elements [13] (Fig. 1.17). Analogous to 2D phased array, all elements in the matrix array are active during beam forming. Because of the large number of elements the process of beam forming is divided into two areas: (1) pre-beam forming by custom made integrated circuits within the transducer handle, and (2) traditional digital beam forming within the ultrasound system [11, 14, 15]. The most important aspect of 3D beam forming is the ability to steer in both ­lateral and elevational directions, thereby providing a pyramidal 3D dataset. However, the collection of such large volumes of data using standard beamforming techniques can result in unacceptably low temporal resolutions. To accommodate the tremendous amount of information that is received from a matrix transducer while performing 3D imaging, while maintain-

ing clinically acceptable spatial and temporal resolution, manufacturers have incorporated parallel processing/parallel beamforming techniques to achieve multiline acquisition [11], and also multibeam transmission. This technology can also be used to enhance 2D imaging as well. 3D technology and imaging (specifically in the context of 3D TEE) is discussed in Chap. 2 as well as Chaps. 23 and 24.

TEE Transducers All current 2D TEE probes utilize phased array technology, usually in a row of 64 elements for adult multiplane 2D TEE probes (pediatric probes have fewer elements—see Chap. 2). TEE probes are constructed similar to standard transthoracic transducers: they have a collection of piezoelectric elements, backing material, electrical connector, housing, and matching layer. In addition, an acoustic lens is added below the matching layer to improve focusing (Fig. 1.18). The important difference is that all the components, as well as the housing, are much smaller, and special cabling is required for anterior/posterior flexion (anteflexion/retroflexion) and (in some probes) right/left rotation. In addition, with multiplane

1  Science of Ultrasound and Echocardiography Fig. 1.17  Matrix array three-dimensional (3D) transesophageal echocardiography probe. The transducer is a square matrix of at least 50 × 50 elements (2500–3000 total elements). A pyramidal 3D dataset is produced from this. Each individual element is just larger than the diameter of a human hair (photograph on the right, courtesy of Philips Medical Systems, Andover, MA)

15

Matrix of at least 50 x 50 elements

Internal rotation

Impedance matching layer

Acoustic lens Piezoelectric elements

Electrodes + Electrical connector Backing material

Fig. 1.18  Internal layout of a multiplane transesophageal echocardiographic probe. The probe utilizes phased array technology; the array of elements can be rotated between 0° and 180° by either an electronic or mechanical control in the transducer handle. The other elements inside

the probe tip are similar to those found in a transthoracic probe. The probe is similar to a gastroscope, with controls for tip movement anteriorly/posteriorly and right/left

TEE probes the piezoelectric elements can be electronically or mechanically rotated by a cable attached to the elements, allowing the tomographic plane to be varied between 0° and 180°. The newer TEE probe technology incorporates the capability for 3D/4D imaging, utilizing the 3D matrix array described above. More detailed discussion of TEE technology is given in Chap. 2.

Pulse Repetition Frequency Ultimately, one of the major factors determining the quality of information obtained by ultrasonic imaging, particularly that of echocardiography, is the speed of sound in tissue. This generally fixed value imposes certain restrictions on pulse-echo imaging as well as pulsed wave and color flow

16

Doppler evaluation—specifically, it places limits on the at maximum rate at which ultrasound pulses can be emitted. A transducer cannot send and receive ultrasound pulses at the same time; once a pulse has been sent, the transducer must wait a certain period of time for returning echoes, with the round-trip time depending upon the depth of the reflector. The equation relating distance to time is:

P. C. Wong



D=

cT 2

(1.6)

Thus, for ultrasonography and echocardiography, it is axiomatic that time equals distance: the transmit/receive time (divided by 2) serves as the measurement for distance. Returning echoes along a scan line will have their various depths registered as a function of their time of return, as cal2D T= (1.5) culated by Eq. 1.6. In addition, these returning echoes will c have different amplitudes that correspond to the different reflectors encountered. In the past, the amplitude of returnT = Time it takes a pulse of sound to travel to a reflector, and ing signals was displayed directly by an oscilloscope (known for an echo to return to the transducer (round-trip time) as “A-mode”). However, all modern-day echocardiography D = Distance from the transducer platforms convert the amplitude of returning echoes to a corc = Speed of sound in the medium responding gray scale value for display on a computer monitor—this is known as brightness mode, or “B-mode”. By Given a speed of sound in tissue of 1540 m/s, the round-­ plotting these varying brightness points as a function of distrip time is equivalent to 13 𝝁sec per cm of depth, hence the tance from the transducer, one scan line can be displayed. If time needed to collect all returning echoes from a scan line successive scan lines are rapidly swept across the object of of depth D is equal to 13 𝜇sec × D. This time is also known interest, a 2D image can then be assembled, with the echo as the pulse repetition period, and the reciprocal of this is signal location on the display corresponding to the reflector known as the pulse repetition frequency, or PRF. This is a positions in relation to the transducer (Fig.  1.19). As disvery important concept in echocardiography, because the cussed previously, this scan line sweep is performed elecmaximum PRF represents the maximum number of times a tronically with a phased array transducer, using electronic pulse can be emitted per second. Pulse repetition frequency time delay sequences to vary the activation of the individual will vary with the speed of sound in different media. elements and sequentially “steer” the scan lines. Typically, However, assuming a constant speed of sound (as is seen 100–200 separate scan lines are used for a single 2D image with soft tissues in the human body), PRF is totally depen- [3]. For echocardiography, this process must be repeated rapdent upon depth: the greater the depth, the less the maximum idly in order to depict accurate, real-time cardiac motion. PRF. In the soft tissues of the human body, maximum PRF The process whereby the reflected echoes are converted to calculates to 77,000/sec per cm of depth (roughly equiva- real-time, 2D echocardiographic images requires highly spelent to 1 divided by 13 𝜇sec). Typically, PRF is expressed in cialized and advanced technology, as well as sophisticated units of Hz or kiloHz (KHz). For example, for a depth of digital signal processing capabilities. Returning echo signals 10 cm, the maximum PRF for one scan line will be 77,000 ÷ from reflectors along each scan line are received by all the 10 cm, or 7700/sec (also given as 7700 Hz or 7.7 KHz). In phased array elements in the transducer; as noted previously, other words, for this particular depth, the maximum number electronic receive focusing is performed to bring returning of times a sound pulse can be transmitted and received is signals into phase. Analog to digital conversion also occurs 7700 times per second. As will be seen, the PRF plays an during this process. To compensate for different reflector important role in determining the limits of temporal resolu- depths, this receive focusing is adjusted dynamically and tion for both 2D imaging as well as the maximum velocities automatically by the digital beam former. These digital sigmeasurable by pulsed wave and color flow Doppler. nals are then sent to a receiver in the ultrasound machine, where they undergo a number of preprocessing steps to “condition” the signal; these include signal preamplification and Generation of an Echocardiographic Image demodulation, as well as operator-adjustable time gain compensation (TGC), noise reduction (known as reject), and The pulse-echo principle serves as the fundamental concept dynamic range/compression (that varies contrast). The TGC underlying ultrasonic and echocardiographic imaging. This is a selective form of amplification used to compensate for principle is based upon a predictable and reliable constant: the weaker, attenuated signals from increased depths. Some the speed of sound in the soft tissues of the human body, of this can be performed by the operator, but modern echowhich, as noted above, is 1540 m/s. When an acoustic pulse cardiography machines now incorporate an adaptive TGC is emitted by a transducer, the time delay between transmis- that automatically adjusts the TGC in real-time [3]. The sion and signal detection can be used to calculate distance operator-adjusted TGC controls will be discussed in a sepafrom the transducer, by rearranging Eq. 1.5 above: rate section below.

1  Science of Ultrasound and Echocardiography

17

Final B-mode 2D image

Fig. 1.19 Generation of a two-dimensional (2D) echocardiographic image. The returning echo amplitudes from one scan line are converted to pixel gray scale brightness on a computer monitor. This is also known as “B-mode” (for brightness mode). If successive scan lines are obtained

and rapidly swept across the sector, a 2D image can be generated. This process must be repeated rapidly in order to depict accurate real-time cardiac motion

Once the signals have been amplified and processed, they are sent to a scan converter, which is a digital imaging matrix used to store and buffer returning signal information. In the process, the returning echo signal locations are converted from polar to Cartesian coordinates—in other words, angle and depth information are converted to a matrix format (rectangular coordinates, usually a 512 × 512 pixels) for display on a computer monitor. A common setup is a matrix of 512 × 512 pixels, with each pixel having 8 bits of storage allowing 256 levels of gray scale (though other types of setup are possible) (Fig. 1.20). Location information is obtained from: (a) angle of the scan line in relation to a reference axis, which is parallel to the surface of the array elements; (b) distance from the scan line to the reflector, as calculated from Eq. 1.6 above. These two coordinates are then converted into Cartesian x and y coordinates, which can then be placed into a large rectangular matrix suitable for pixel mapping on a 2D computer display. What becomes apparent during this conversion process is that, when the scan lines are superimposed upon the matrix, adjacent scan lines will not sample all of the pixels in the matrix. To fill in these areas, a process of interpolation is performed in which an averaged signal from nearby pixels is used to fill in the value of the blank (unsampled) pixel (Fig. 1.20). In the scan converter, image data can be held in memory and continuously updated with new echo data. At the same time, information is continuously read out to a video buffer

to provide real-time visualization of the scanned images on a video monitor. Most echocardiography systems now use a large digital computer monitor, generally one based upon liquid crystal display (LCD) or even more advanced technology (such as organic light-emitting diode, also known as OLED). Various postprocessing techniques can also be performed on the digital image data stored in the computer memory; these techniques include contrast and edge enhancement, as well as smoothing and B-mode color. For echocardiography, image acquisition, updating and display must be performed in a rapid fashion to portray real-time cardiac motion. Almost all ultrasound systems also have a freeze option that stops image acquisition (still frame) and allows visualization of a single image (for measurements or text labeling), and also a review of short cine loops. This feature is very useful for echocardiography, because it gives the ability to slow down and review rapidly moving images associated with cardiac motion. It also facilitates interpretation of the acquired data relative to the phases of the cardiac cycle as displayed by concurrent electrocardiographic monitoring. Instead of sweeping a B-mode scan line in an arc to obtain a 2D image, a simpler (and less processor-intensive) method can be used to display the B-mode data. If the scan line remains fixed, and instead a continuous recording of the line is made over time, then an M-mode tracing is obtained—the

18

P. C. Wong

Fig. 1.20  Scan converter. The scan lines are converted from polar to Cartesian coordinates, and the information placed in a scan converter matrix, and used to construct a 2D image that can be visualized on a computer monitor. A common setup is a 512 × 512 pixel matrix, with each pixel having 8 bits of storage allowing 256 levels of gray scale. However, other matrix sizes and bits/pixels are possible. Interpolation is performed for those pixels in which no scan line information is available

Interpolation

Scan Converter M stands for motion (Fig. 1.21). This type of display was the principal form of echocardiography used in the 1970s and early 1980s. Because only one scan line is involved, a high PRF can be used and therefore this mode has excellent temporal resolution. Frame rates of 1000–2000 scan lines are possible, significantly increased compared to standard frame rates of 30–120 frames/second for 2D imaging. Axial resolution is also excellent, making M-mode ideal for linear and time measurements. For example, M-mode measurements are very useful for assessment of left ventricular dimensions and function, such as calculation of left ventricular end diastolic dimension and shortening fraction. Since there are published normal ranges and values for M-mode measurements, these measurements serve as an important method of distinguishing normal vs. abnormal cardiac size and function (discussed in Chap. 5). However, M-mode does not provide a real-time 2D display of cardiac anatomy, making interpretation more difficult, and limiting its effectiveness with CHD. Thus M-mode imaging has largely been supplanted by

2D and 3D echocardiography. While still available on modern echocardiography machines, it generally comprises a very small fraction of a total examination.

Image Resolution Resolution is a term commonly used to describe the quality of an ultrasonic image. With ultrasonic imaging, and specifically with echocardiography, there are three major forms of resolution: spatial, contrast, and temporal. These will be discussed below.

Spatial Resolution Spatial resolution refers to the ability to discriminate objects in space, and applies specifically to 2D imaging. It is defined as the ability to distinguish two discrete objects located in close proximity to each other—in other words, the ability to resolve them as separate as opposed to overlapping struc-

1  Science of Ultrasound and Echocardiography

19

a

Fig. 1.21  Generation of an M-mode image. In this instance, the 2D image (a) is used to guide the placement of the scan line (yellow dotted line) for M-mode assessment (b). Real-time information is then

b

obtained along the single scan line, plotted as time (x axis) vs. depth from the transducer (y axis). M-mode imaging is characterized by excellent axial and temporal resolution

Fig. 1.22  The three spatial resolution planes: axial, lateral, and elevational (slice thickness)

Axial Elevational (Slice thickness) Lateral

tures. There are three types of spatial resolution: axial, lateral and elevational, representing the x, y, and z planes of a 2D ultrasonic/echocardiographic image (Fig.  1.22). Axial and lateral resolutions affect the two planes readily seen on a 2D image; elevational resolution refers to the “hidden” plane perpendicular to the other two planes, and not as apparent on 2D imaging. Factors affecting the resolution in each plane are discussed below.

Axial Resolution Axial resolution describes the ability to discriminate two objects located along the axis of the sound beam (i.e. the scan line). It is determined principally by the transmitted ultrasonic pulse duration. The pulse duration is itself deter-

mined by two major factors: the number of cycles in the pulse, and the wave period (which is the inverse of frequency). In order to distinguish two separate objects along the axis of the sound beam, it is necessary that there be a short pulse duration (Fig.  1.10)—specifically, the time gap between the arrival of two pulses from two separate reflectors should be greater than the length (duration) of each pulse. Otherwise, there will be overlap of the two pulses and the two reflectors will not be resolved (Fig. 1.23). To improve axial resolution, the pulse duration should be decreased. This can be achieved by two methods. One is to use a higher frequency transducer, which decreases wavelength and wave period. The other is to improve damping of the “ringing” of the transducer so that each pulse will have fewer cycles.

20

P. C. Wong

Fig. 1.23  Axial resolution. This diagram illustrates the effect of pulse duration on axial resolution. Each panel shows two pulses from two separate reflectors. In the top panel, the pulse duration is longer (which can be due to lower frequency, more cycles/pulse, or both). However, because the two reflectors are spaced further apart, the longer pulses are still able to distinguish them as separate objects. In the middle panel, the reflectors are closely space and the long pulses are no longer able to

distinguish the objects as separate; the two pulses overlap and appear to be one on the monitor. In the bottom panel, the two reflectors are still closely spaced (as in the middle panel) but pulse duration has been shortened by the use of a higher frequency and/or decreased number of cycles/pulse. The shorter pulse duration enables the two objects to be shown as separate objects on the screen, hence axial resolution has been enhanced

Broad bandwidth, high frequency transducers will provide the best axial resolution. The typical axial resolution for most modern ultrasound systems is between 0.3 and 2.0 mm; a rule of thumb is that the axial resolution of a system is 1.5 times the wavelength of the system. Therefore for a 7.5  MHz transducer, axial resolution is 0.3 mm [16]. In general, axial resolution tends to be the best of all the three dimensions. It is fairly constant with depth, though signal attenuation plays a role with the higher frequency transducers.

of the ultrasound scan line. This is determined by two factors. The first is beam width: if the width of the beam is less than the distance between the two reflectors, then they can be resolved. Otherwise, if the beam is too wide, the images merge together and the two reflectors cannot be resolved (Fig.  1.24). Beam width changes with distance from the transducer; optimal beam width occurs within the near field (Fresnel) zone, prior to beam divergence. A long near field zone is therefore preferable for ultrasonography and echocardiography, and as noted previously in Eq. 1.4, the depth of the Fresnel zone is equal to d2/4λ. Two important observations can be gleaned from this equation. First, lateral resolution can be improved by using a larger transducer aperture (diameter), which extends the depth of focus and lengthens

Lateral Resolution Lateral resolution refers to the ability to distinguish two closely spaced reflectors positioned perpendicular to the axis

1  Science of Ultrasound and Echocardiography

the near field. Second, using a higher transmitted frequency will also extend the length of the near field, thereby improving lateral resolution further along the scan line (Fig. 1.25). However, this latter point must be balanced by the greater attenuation of higher frequency sound waves, which can limit the depth of penetration. Focusing a beam (mechanically or electronically) will also enhance lateral resolution by narrowing the beam width; the best resolution occurs within the focal zone, where the beam is narrowest (Fig. 1.14). With phased array transducers, dynamic adjusting of the focal zone to the desired depth can be performed to optimize the lateral resolution for that level. The other important factor affecting lateral resolution is especially pertinent to echocardiography. This involves line spacing or line density. As will be discussed in the section on temporal resolution, the frame rates for real-time 2D imaging depend upon the depth of scanning as well as the number of scan lines per imaging sector. To improve frame rates, the number of scan lines can be reduced, with the result being less scanning time required per sector, but increased spacing between scan lines. This can reduce lateral resolution

Screen Display

Fig. 1.24  Lateral resolution. This diagram illustrates the effect of beam width on lateral resolution. Two reflectors can be distinguished separately when the beam width is less than the lateral distance between two reflectors. When the beam is wider than this distance, the two objects cannot be resolved as separate reflectors

21

because even with a narrow beam width, if the line spacing is greater than the distance between two closely spaced objects, the objects still might be not be resolved as separate reflectors. Typically, at a depth of 10 cm, a beam width of approximately 2 mm is achieved (obviously this will be affected by signal frequency and transducer size). Thus, lateral resolution tends to be less than axial resolution, and unlike axial resolution, it exhibits depth-dependence. Nonetheless lateral resolution is a major factor determining the quality of ultrasound images. For this reason, modern echocardiography manufacturers attempt to enhance lateral resolution by utilizing combinations of time-delayed firing and changing beam aperture—available with phased array technology—to optimize focusing at different depths (also known as multiple focal zones). This effectively lengthens the focal zone. However, as noted above, it requires multiple pulse sequences, which can reduce temporal resolution.

Elevational Resolution Contrary to appearances, a 2D tomographic image is not flat. It is in fact a slice, and this slice has a thickness aspect, which is known as the elevational plane with an axis perpendicular to the imaging plane (Fig. 1.22). Similar to lateral resolution, slice thickness depends upon beam size—that is, the size of the beam in the elevational plane. However, unlike lateral resolution, in most standard 2D transducers there is no electronic focusing available in this plane; a fixed focal length acoustic lens generally determines beam width in this dimension. Slice thickness is minimal closest to the focal zone, and widens beyond that point. As with lateral resolution, a higher frequency transducer improves the elevational resolution by lengthening the near field. Slice thickness is also determined by the width of the beam in the elevational plane. What is the importance of elevational resolution? While the elevational plane is not displayed in a conventional 2D image, objects that exist within the slice can overlap with the 2D image being displayed, potentially causing slice thickness artifacts. Of the three types of resolution, the elevational resolution is usually the worst. In most phased array transducers, eleva-

Low frequency High frequency

Fig. 1.25  Effect of frequency on near field length and beam width. In this diagram both beams have been focused. However, even with a focused beam, using a higher frequency transducer lengthens the focal zone and near field, and there is less divergence in the far field

22

tional slice thickness ranges between 3 mm (near the focal zone) to 10 mm as the beam diverges [17]. While little information is available regarding elevational resolution in TEE transducers, slice thickness artifacts are likely to minimized due to a several factors: (a) higher frequencies of the transducer; (b) some focusing from the transducer’s acoustic lens; (c) reduced transducer depth, usually about 5–10 cm in the vast majority of patients for most TEE views except for the deep transgastric views.

Optimizing Spatial Resolution From the above discussion it becomes apparent that the best spatial resolution occurs in the near field and focal zone of the transducer. Beyond this area, lateral and elevational resolution decrease as the beam diverges. Use of higher frequency transducers improves axial resolution and lengthens the near field, thereby improving lateral and elevational resolution. Focusing of the beam further decreases beam width at the focal zone, thereby improving lateral and elevational resolution. However, focusing can increase beam divergence, and lateral/elevational resolution are reduced in the far field. While axial resolution does not change with depth, with greater depths there is reduced penetration of higher frequency ultrasound, thus lower frequencies must sometimes be used for imaging of more distant structures, leading to reduced resolution. Therefore, for echocardiographic 2D imaging, as a rule it is desirable to position the transducer as close as possible to the object of interest, and to use the highest frequency transducer possible. Fortunately, these conditions can be achieved with most TEE imaging, as the close proximity between esophagus and heart (from most TEE windows) enables the optimization of spatial resolution in all three planes.

P. C. Wong

process, the compression can be adjusted by the operator to vary the dynamic range of the signal amplitude. Increasing the dynamic range increases the range of gray scale and decreases contrast; decreasing the dynamic range does the opposite. It should be noted that improving the contrast often improves the ability to distinguish structures, thereby enhancing spatial resolution.

Temporal Resolution Temporal resolution refers to the ability to visualize smooth real-time motion, and is related to image refresh speed, also known as frame rate. Frame rate is dictated by four factors: the speed of sound, sampling depth, the number of separate transducer beam lines used to form an image, and the ­number of focal zones. The equation relating these variables is given as follows:

F=

c 2 DNn

(1.7)

F = frame rate c = speed of sound D = sampling depth N = number of sampling lines per frame n = number of focal zones used to produce one image

Pulse repletion period and PRF play an integral role here. As noted previously, a small time period is required for a pulse to be transmitted and for collection of all echoes emerging from that scan line. The round-trip time per scan line in soft tissue (pulse repetition period) is 13 μs per cm of depth. Therefore, for an image sector 10 cm deep (from the transducer), the pulse repetition period is 130 μs. If the image sector is composed of 100 scan lines, the time for one image equals 13 milliseconds, thus the maximum frame rate is approximately 77 frames/second. This is with a single focal Contrast Resolution zone; if multiple transmit focal zones are used (advantageous Contrast resolution refers to the ability to differentiate for improving lateral resolution), then frame rate decreases between body tissues that have slightly different properties, because multiple pulse sequences must be generated per scan and therefore different acoustic impedances, using different line. What becomes apparent is that frame rate is principally shades of gray on the display. There are two components to affected by sampling depth and number of scan (beam) lines. contrast resolution. The first is the intrinsic contrast, and how Deeper scanning depths as well as wider imaging sectors this is encoded in the stored pixel values in the image mem- (requiring more scan lines) will appreciably lower frame ory. Intrinsic contrast depends upon the different tissue inter- rates. To improve frame rates, a smaller depth should be faces/acoustic impedances, as well as acquisition parameters used. The number of scan lines can be decreased in one of (beam width, pulse shape) and processing (compression, two ways: (a) decreasing the number of scan lines while edge enhancement). It also depends in part on how gray scale maintaining the same size imaging sector (however this is encoded in the process of analog to digital conversion of increases lateral line spacing, thereby reducing lateral resothe amplified voltage signal: the larger the number of bits per lution); (b) narrowing the imaging sector while maintaining pixel, the larger the number of gray scale shades available. the same line spacing (which maintains lateral resolution but Extrinsic contrast translates these pixel values into bright- decreases the field of view) (Fig. 1.26). Of course, any comness levels on the monitor, and is dependent upon operator-­ bination of these maneuvers can further improve temporal adjustable contrast and brightness controls. During this resolution. In addition, newer technologies are now being

1  Science of Ultrasound and Echocardiography

23

D = Distance N = Number of scan lines

Sector width

Temporal resolution can be improved by:

Reduced Depth of Scanning D: Decreased N: Unchanged Sector width: Unchanged

Fewer Scan Lines D: Unchanged N: Decreased Sector width: Unchanged

Smaller Imaging Sector D: Unchanged N: Decreased Sector width: Decreased

Fig. 1.26 Enhancement of temporal resolution. Temporal resolution is dependent upon sector depth and number of beam lines. It can be improved by several methods, including: (a) reducing sector depth (left panel); (b) reducing the number of scan lines without changing sector width, effectively

reducing line density (middle panel); (c) narrowing the sector width, which also has the effect of decreasing the number of scan lines while maintain line density (right panel). Any combination of these maneuvers can be performed to enhance temporal resolution further

employed including parallel processing, which allows more scan lines to be acquired at one time, thereby reducing the total time require to acquire the image. In the realm of diagnostic medical ultrasound, temporal resolution considerations are especially applicable for echocardiography because of one simple fact: the heart is in con-

stant motion. For visualizing a rapidly moving structure such as the heart, the image must be refreshed a minimum number of times per second to produce the appearance of smooth, real-time cardiac motion; otherwise a “strobe” effect is created, and motion no longer appears smooth and can be difficult to interpret. The minimum frame rates needed to present

24

smooth real-time motion will vary depending upon heart rate—the faster the heart rate, the greater the necessary frame rate. While no published standard exists, for visualizing cardiac motion it is generally desirable to have a frame rate that allows for at least 10 samplings (frames) per cardiac cycle; 20–30 frames per cycle will usually provide good temporal resolution. Conversely, when the rate decreases to less than 5 frames per cardiac cycle, cardiac motion ceases to be smooth and important information can be lost because of the inadequate sampling rate. Thus, for a heart rate of 100/min, a frame rate of 50 frames per second will yield 30 frames per cardiac cycle, thereby providing acceptable temporal resolution. However, a frame rate of 10 frames per second yields only 6 frames per cardiac cycle, which is barely adequate for most cardiac imaging. In such instances the operator should attempt to boost frame rates by using the maneuvers outlined above. Obviously, one should strive for the highest frame rates possible, which will permit more detailed analysis of cardiac motion and function; this is especially pertinent given the higher heart rates found in young children. Very high frame rates are also desirable for precise evaluation of myocardial mechanics using methods such as tissue Doppler evaluation and strain/strain rate imaging. Fortunately, with TEE the close proximity of the transducer to the heart means that smaller distances are needed to visualize the cardiac structures. Hence excellent temporal resolution is generally possible, even while at the same time being able to use higher ultrasound frequencies to optimize axial and lateral resolutions.

 issue Harmonic Imaging T Tissue harmonic imaging is a relatively new technique used to enhance 2D imaging, particularly in patients with poor echocardiographic windows. It is based upon the detection of harmonic frequencies generated by beam propagation through tissue. It relies upon the fact that a relatively high-­ pressure amplitude sound wave changes shape during propagation; this is known as nonlinear wave propagation. The sinusoidal shape becomes distorted, and this change in shape corresponds to a change in frequency components of the sound wave—harmonic frequencies are generated from the original sound wave, and these intensify with distance from the transducer as the waveform becomes more distorted. The harmonic components occur as multiples of the fundamental frequency: if the fundamental frequency is 2.5 MHz, the second harmonic is 5.0 MHz, the third harmonic 7.5 MHz, etc. However, the third and higher harmonics have weak amplitudes and therefore harmonic imaging is confined principally to the second harmonic frequency. Tissue harmonic imaging relies upon the detection of this second harmonic frequency. The ultrasound machine can be configured to isolate this component for image formation. The advantage of this type of imaging is that artifacts are reduced or eliminated because they all arise from the funda-

P. C. Wong

mental frequency, which is suppressed with tissue harmonic imaging. Thus, signal to noise ratio is increased, and contrast resolution and border delineation are enhanced. Moreover, the width of the main beam is effectively narrower than the main beam at the fundamental frequency, thus lateral resolution can be enhanced. The drawbacks of harmonic imaging depend upon the methods used for second harmonic isolation. One method, known as harmonic band filtering, utilizes longer spatial pulse length to narrow transmission bandwidth and enhance separation of fundamental and harmonic frequencies. However, the longer spatial pulse length can lead to poorer axial resolution. The other method, known as pulse phase inversion, utilizes a two-pulse sequence in which the second pulse is shifted 180° in phase. With standard sinusoidal waveforms, summation of these two returning pulses would cancel each other out. However. with nonlinear propagation, the returning harmonic components that are generated are not identical in amplitude, thus summation of the returning signals will isolate the harmonic frequency that has been produced. Broadband transmitted pulses with short spatial pulse length can be used, so this method preserves axial resolution; however, using the multiple pulse technique can reduce temporal resolution and produce motion artifacts [18]. Harmonic imaging has found great utility in transthoracic echocardiographic imaging of adult patients with poor windows, and occasionally it proves beneficial in selected pediatric patients because of its improvements in contrast resolution. It has less applicability with TEE because of the close proximity and generally excellent imaging afforded by the proximity of the esophagus to the heart [19].

Doppler Echocardiography In addition to providing information about anatomy and function, ultrasound can also provide important information about motion and velocity. This is particularly relevant in echocardiography, where knowledge of cardiac and blood flow velocities—made possible through the use of Doppler echocardiography—can be used to derive a wealth of noninvasive information on cardiac physiology. This section discusses the science of Doppler echocardiography.

The Doppler Principle The Doppler effect was discovered and first described by the Austrian physicist Christian Johann Doppler in 1842. While studying the light from the stars, he discovered that the colored appearance of moving stars was caused by their motion relative to the earth. The motion resulted in either a red or blue shift of the light’s frequency, depending upon the direction of motion. Doppler mathematically described

1  Science of Ultrasound and Echocardiography

25

Stationary Reflector

Returning frequency same as transmitted frequency

Reflector moving towards transducer

Returning frequency increased

Reflector moving away from transducer

Returning frequency decreased

Fig. 1.27  The Doppler principle. When an ultrasound pulse of known frequency is transmitted, the returning pulse from a stationary reflector will have an identical frequency. However, the pulse returning from a reflector moving towards the transducer will have an increased fre-

quency, and if the reflector is moving away from the transducer, the pulse will have a decreased frequency. The change between incident and reflected frequencies is known as the Doppler frequency shift, and from this shift, the reflector velocity can be calculated

the shift that occurred, and also correctly surmised that the same type of perceived frequency shifts would occur for a stationary observer listening to sound waves produced from a moving source. The perceived frequency of sound would be higher (compared to the emitted frequency) for an approaching object, and lower for a retreating object (Fig. 1.27). The Doppler principle can also be applied to ultrasonography, and specifically to echocardiography. The ultrasound transducer serves as the stationary observer, and emits a sound of known frequency toward a moving target. The signal reflected from the moving target will return with a different frequency (the Doppler shift), and this change in frequency is proportional to the velocity of the reflector. The velocity of the moving reflector can be calculated using the Doppler equation:

𝜃 = the intercept angle between the ultrasound beam and the direction of blood flow c = the velocity of sound



fD 

2 f0V cos  c

fD = the Doppler frequency shift = fr—f0 f0 = the transmitted frequency of sound fr = the received frequency of sound V = reflector velocity

(1.8)

If this equation is rearranged to derive the reflector velocity from the frequency shift between transmitted and received ultrasonic signals, the following equation is obtained: V

fr  f 0 c x cos  2 f0

(1.9)

From these equations, three important points become apparent. First, the angle (𝜃) of the ultrasound beam relative to the direction of reflector motion (also known as the angle of insonation) is important—as 𝜃 becomes less parallel and changes from 0° to 90°, the Doppler frequency shift (fd) is reduced by the factor cosine 𝜃. When the direction of the beam is perpendicular to reflector motion, cosine 90° = 0 and no frequency shift is detected. Table 1.2 shows the reduction in calculated velocity (as compared to actual velocity) as 𝜃 increases from 0° to 90°. Angles greater 30° result in significant decreases in calculated velocity. The message here is simple and straightforward: when evaluating for a Doppler velocity, the angle of insonation must be as parallel as possible to the direction of motion.

26

P. C. Wong

Table 1.2  Doppler angle and velocities for a 5 MHz transducer Doppler angle (degrees) 0 30 45 60 75 90

Doppler shift (KHz) 6494 5624 4592 3248 1681 0

Actual velocity (cm/s) 100 100 100 100 100 100

Calculated velocity (cm/s) 100 87 71 50 26 0

The second important point is that the Doppler frequency shift depends upon the frequency of the incident beam—for a given reflector velocity, the higher the incident frequency, the higher the Doppler shift. As will be seen, the magnitude of this frequency shift is important in determining the ability to perform pulsed and color flow Doppler evaluation. The third important point is that reflector direction of motion can be determined. As is evident from Fig. 1.27, the Doppler frequency shift incorporates directionality: approaching objects increase the returning frequency of the signal, and retreating objects decrease the frequency. While the process in which the echocardiography machine determines reflector direction is not as straightforward as might appear from Eq. 1.9, the fact remains that reflector direction of motion is another important piece of information that can be extracted from the returning echo signal. Doppler echocardiography plays a major role in the noninvasive hemodynamic evaluation of the cardiovascular system, primarily for the assessment of blood flow in the arterial and venous systems. Because red blood cells (Rayleigh scatterers) reflect ultrasound, blood flow evaluation by Doppler can readily be performed, and from this a great amount of hemodynamic information can be derived. In addition, myocardial motion can also be assessed by Doppler, yielding important information about myocardial systolic and diastolic function and mechanics. There are several methods in which Doppler information can be displayed by echocardiography: spectral, color flow Doppler, and audible Doppler. These will be presented below.

Spectral Doppler In the example given above, a single velocity was used to characterize a moving object. However, it is a simplistic notion to view flow in the human blood vessel as a constant river or stream of one single velocity; in fact, quite the opposite is true. In the human body, blood flow in the heart, arteries and veins is not steady, and exhibits considerable variation during the cardiac cycle, especially given the pulsatile nature of cardiac output. Blood flow also varies with external factors such as inspiration/expiration. Moreover, even in the

normal flow through a vessel, at any one point there is a distribution of velocities, with a much higher velocity in the center of the vessel compared to flow near the periphery (adjacent to the vessel wall). This is known as laminar flow, and is due to the friction between layers, resulting in the lowest velocities along the wall, and the highest velocities centrally. Thus, the velocity profile assumes a rounded or parabolic configuration, as noted in Fig. 1.28. A laminar flow pattern is characterized by a smooth, organized and orderly appearance. With higher blood flow velocities, such as those encountered with vessel or valve stenosis, there is a loss of orderliness in blood flow. This is known as turbulence. The blood flow pattern presents a chaotic picture, with flow orientation in a number of different directions, and considerable dispersion in detectable blood flow velocities. (Fig. 1.28). Whether laminar or turbulent, the returning Doppler signal from blood is seen as a complex wave representing a combination of frequency shifts produced by different velocities. Doppler spectral analysis is the process whereby this

Parabolic

Blunt

Turbulent

Fig. 1.28  Laminar vs. turbulent flow in a blood vessel. In normal vessels, the blood cells move fastest along the central axis of the vessel, and the velocity decreases virtually to zero next to the vessel wall. While blood flow direction is still orderly and well-organized, there is a parabolic appearance to the flow in the vessel (top panel). In larger vessels, this flow takes on a more blunted profile, with less variation in velocities in the center of the vessel (middle panel). When turbulence occurs, such as when blood passes through an area of obstruction, a disordered and chaotic flow pattern is produced (lower panel)

1  Science of Ultrasound and Echocardiography

27

a

c Frequency 1

Frequency 2

Fast Fourier Transform

Frequency 3

b 130

High

110 Number of scatterers

90 Velocity (cm/sec)

70 Low

50 30

Time (msec)

Fig. 1.29  Spectral Doppler display. The returning Doppler velocity profile is complex, and contains a range of different Doppler frequencies that can be analyzed into simpler frequency components by the use of a fast Fourier transform (FFT) analyzer (a). A spectral analyzer then produces a record showing the relative amount of signal within each of

several discrete bins corresponding to the relative amount of each signal. The Doppler spectral display (b) provides a readout of velocity vs. time, with the pixel brightness reflecting the relative amount of scatterers with that velocity at that point in time. In this way, a spectral Doppler tracing is obtained (c)

complex signal is broken down and analyzed into simpler frequency components. In echocardiography, the process most commonly used is known as Fourier analysis, and the device used to perform the analysis is called a fast Fourier transform analyzer. A spectral analyzer then records the relative amount of signal for several discrete frequency “bins”. This analysis allows the amount of Doppler signal present at different frequencies to be displayed as a function of time. When evaluating blood flow, the low velocity signals originating from myocardial motion are filtered. At any given time point, the distribution of velocities is shown on the y axis; for each velocity, pixel brightness corresponds to the quantity of red blood cells with that velocity. By obtaining successive signals, a continuous spectral display of velocity vs. time is obtained. In essence, a visual display is created showing the breakdown of velocities (frequencies) plotted as a function of time (Fig. 1.29). By convention, flow direction is depicted as above the baseline when flow is toward the transducer, and below the baseline when flow is away from the transducer (Fig. 1.30). When there is a narrow range of velocities present, such as that seen with smooth laminar flow, the spectral envelope displays a small band along the top edge of the spectral envelope corresponding to the range of velocities. The brightness of the pixels of a given velocity in the display corresponds to the number and frequency of reflectors with that velocity. A darker spectral “window” is

seen underneath this band because no other velocities are present. With a wider range of velocities sampled, such as turbulent blood flow or with continuous wave Doppler, the spectral window becomes “filled in”. This is also known as spectral broadening (Fig. 1.31). Spectral Doppler evaluation represents the fundamental basis for quantitative noninvasive hemodynamic assessment. From the spectral curves, a number of important parameters can be used for analysis including peak velocity, mean velocity as calculated using the time-velocity integral (represented by the area under the curve for a single cardiac cycle), and acceleration. Applications for these will be discussed in subsequent portions of this chapter, and also in other chapters of this textbook. There are two principal methods of spectral Doppler analysis: continuous wave and pulsed wave Doppler. These two methods will be discussed below. What will become apparent is that these two methods are complementary—each has its own strengths and weaknesses, but the strengths of one complement the weaknesses of the other, and ideally both should be used together for a full Doppler evaluation. For transthoracic, fetal and TEE, modern phased array transducers have the capability of performing B-mode imaging and spectral Doppler evaluation (such systems are sometimes called “duplex scanners”). These transducers can rapidly alternate between imaging and spectral Doppler eval-

28

P. C. Wong

Fig. 1.30  Spectral Doppler displaying flow directionality in this patient with to and fro flow across a patent ductus arteriosus. Flow below the baseline represents flow away from the transducer; flow above the baseline represents flow towards the transducer

uation. The transducer “time-shares” between both, displaying the spectral Doppler tracing while at the same time periodically updating the 2D image to verify location of the Doppler cursor. Broadband phased array transducers can also be optimized for both modes—they can operate at lower frequencies in Doppler mode to optimize detectability of velocities at increased depths, and high frequency in imaging mode to optimize spatial resolution. In addition, these highly sophisticated transducers also have the capability of ­performing M-mode imaging, tissue Doppler imaging, and (in some instances) more advanced technologies such as 3D and strain imaging/speckle tracking.

Continuous Wave Doppler Continuous wave (CW) Doppler is the simpler of the two spectral Doppler methods. The transducer is essentially divided into two separate elements: a transmitter and a separate receiver. Two elements are needed because both operate continuously: the transmitter continuously excites the transducer to produce a reference signal of known frequency f0 (Fig. 1.31a). The signals returning from reflection and scattering are amplified and combined with the reference (transmitted) signal to create a complex Doppler signal which is then demodulated to obtain the “difference” or “beat” frequency, which is equal to the Doppler frequency shift corresponding to the velocities of the reflectors. The beat signal is amplified, low pass filters remove high frequency signals, and high pass filters remove low frequency (wall) signals. This demodulation yields the Doppler shift, but gives no information regarding directionality. To obtain information about flow direction, a commonly used signal processing technique known as quadrature detection is used. This

method sends the echo signal to two demodulators, and the phase relationship of the two resultant signals can be used to determine whether the Doppler shift is positive or negative. A spectral tracing of velocities vs. time is then created in the manner described above. In practice, many moving interfaces reflect signals to the receiver, thus many beat frequencies are produced. Because of this wide mixture of velocities being sampled, there is significant spectral broadening of the CW Doppler signal (Fig. 1.31b). The advantage of CW Doppler is its ability to measure very high blood flow velocities, in excess of 6–7  m/s (or higher). Because the signal is continuously emitted and sampled, the spectral tracing will not be subject to aliasing (discussed below). This gives it great utility when evaluating areas of stenosis. However, the disadvantage of this technique is a complete lack of depth specificity, also known as range ambiguity. A high velocity might be detected, but based upon the CW tracing alone, it is impossible to determine at what depth this velocity is located. Along the CW beam line, all velocities will be sampled and displayed in one spectral tracing. Therefore, if there are several levels of obstruction, for example if high velocities are present along the line from two (or more) separate locations, it might be very difficult to separate the different velocities.

Pulsed Wave Doppler Pulsed wave (PW) Doppler is used for the evaluation of Doppler signals at a specific range or depth. Using the principle of pulse-echo 2D imaging, PW Doppler involves emitting a signal of known frequency, and by utilizing transmission/reception time in conjunction with the speed of sound in soft tissue, returning signals originating from a spe-

1  Science of Ultrasound and Echocardiography

a

29

b

Continuous Wave (CW) Doppler

Fig. 1.31  Continuous wave Doppler. There are two basic components: a transmitter that continuously sends sound waves of known frequency, and a separate receiver that continuously receives all returning signals (a). The “difference frequency” is plotted as a function of time, yielding a spectral display with a wide dispersion of frequencies and significant spectral broadening (b). In this exam-

ple, a high velocity tricuspid regurgitation signal of approximately 4.2 m/s is obtained. This study was performed with a transesophageal echocardiographic probe with broadband capabilities: B-mode imaging was performed at a frequency of 7  MHz; color flow Doppler at 4.4 MHz, and a frequency of 2.5 MHz was used for the continuous wave Doppler evaluation

cific depth can be isolated and evaluated. However, unlike 2D imaging, the important information evaluated by PW Doppler is not signal amplitude, but rather the Doppler frequency shift of the returning signal, which can then be used to calculate reflector velocity and direction. To perform PW Doppler evaluation, it is necessary to have updated 2D image information so that the desired region of interrogation can be selected; this region is designated on the image by the use of a sample volume, which is usually a pair of small parallel lines orthogonal to a visible scan line on the display. This sample volume can be adjusted for depth and position anywhere within the image (Fig.  1.32a). The sample volume or gate size can also be adjusted for size; increasing the gate size accepts Doppler signals from a longer axial region. Like pulse-echo imaging, the same PZE element serves as both transmitter and receiver of ultrasound pulses. These pulses tend to be longer in duration (spatial pulse length 5–25 cycles) to produce a narrow frequency bandwidth pulse and improved sensitivity, though this comes at the expense of poorer axial resolution and greater acoustic exposure. Using the pulse-echo principle,

only the echoes returning during a specified time window (corresponding to the desired depth, as given in Eqs. 1.5 and 1.6) are selected for analysis. These echoes undergo the same processes of amplification, demodulation and filtering that are utilized with CW Doppler, yielding a velocity and directionality of the moving reflector. The signals are stored in a sample and hold unit, and held there awaiting the results of another transmit pulse. Subsequent ultrasound pulses are repeatedly transmitted as soon as the previous pulses are received; the maximum frequency is the maximum PRF, which, as discussed earlier, is completely dependent upon the depth of the sample volume. In general, a PRF of 4000– 12,000 Hz is utilized with PW Doppler [1] With each pulse transmission-reception, the incoming signals are processed, resulting in the construction of the Doppler signal. The spectral tracing displays the range of velocities over time, with pixel brightness corresponding to the number of reflectors with a specific velocity. With laminar flow, there is a much narrower range of velocities displayed as a small band along the edge of the spectral envelope, and a spectral “window” underneath (Fig.  1.32b). This band broadens slightly with

30

P. C. Wong

a

b

Pulsed Wave (PW) Doppler

Distance

Sample volume

Fig. 1.32  Pulsed wave Doppler. This is used to evaluate Doppler signals at a specific range or depth, and relies upon the pulse-echo principle to determine which signals to sample. A sample volume is placed in the area where Doppler evaluation is desired. (a) Pulses are transmitted over a beam line along which the sample volume is located; however only echoes returning in a time window equivalent to sample volume depth

(depth ∝ [round-trip echo time/2]) are collected. The resultant signals are processed, and a spectral display generated. (b) In this example a spectral Doppler recording has been obtained by transthoracic echocardiography from the ascending aorta. Note that normal blood flow has a narrow range of blood flow velocities displayed as a band of gray scale brightness. This creates an open area underneath known as a “spectral window”

peak flow rates as a more parabolic shape of velocities occurs. Turbulence results in a wider range of velocities and “fill-in” of the spectral window, also known as spectral broadening. As noted previously, with current phased array transducer technology, 2D imaging and Doppler capabilities are all present on one transducer. For PW Doppler, the 2D image information is utilized for precise placement of the sample volume in the desired location. During the periods when the transducer is “listening” for the returning Doppler information, image pulses can be sent. Therefore, an intermittent image update can occur even during the PW spectral Doppler display. The advantage of PW Doppler is that, unlike CW Doppler, the sample volume can be precisely located anywhere within the field of view, enabling collection of velocity information from a specific location. However, this comes with a tradeoff—for PW Doppler there is an upper limit to the maximum velocity that can be measured unambiguously, and this limit varies with depth. This is discussed in the section below.

Aliasing and the Nyquist Limit Unlike CW Doppler, sampling with PW Doppler cannot be performed continuously. The echo pulse transmit/reflect time must be used to determine sample volume distance, which means that one complete pulse must be sent and received before the next is sent. Therefore, a Doppler signal must be sampled at discrete intervals. The greater the sampling frequency, the better the construction of the signal (Fig. 1.33a). For PW Doppler, the sampling frequency is equal to the pulse repetition frequency (PRF). The upper limit of the sampling frequency is given by the maximum PRF, which in turn is dictated by the distance from the transducer: the farther the distance between sample volume and transducer, the less the maximum PRF. To provide an accurate measurement of a reflector’s velocity by PW Doppler, at minimum the PRF needs to be high enough to sample the Doppler frequency shift unambiguously at least twice per wave cycle. If not, a phenomenon known as aliasing occurs in which the reported frequency

1  Science of Ultrasound and Echocardiography

a

b

31

ume is located 5 cm from the transducer, the maximum PRF at that point is 77,000 ÷ 5 or 15,400 Hz. This is more than twice the Doppler frequency shift of 6490 Hz, hence at this distance the velocity can be determined accurately, without aliasing. However, if the sample volume were located at 10 cm, the maximum PRF of 7700 Hz (77,000 ÷ 10) is less than twice the Doppler frequency shift, and aliasing would occur at this level. The Nyquist limit will vary both with sample volume depth as well as the frequency of the signal. The equation for calculation of maximum reflector velocity without aliasing is given as follows:

Vmax 

c2 8 f0 D cos 

(1.10)

Vmax = the maximum measurable velocity of blood c = the velocity of sound in tissue f0 = the transmitted frequency of sound D = depth of interest θ = the intercept angle between the ultrasound beam and the direction of blood flow Fig. 1.33 Examples of adequate and inadequate signal sampling. To describe a wave accurately, there must be adequate sampling of the signal. The greater the sampling frequency, the better the signal is rendered. At the very minimum, sampling needs to occur at twice the frequency of the wave being sampled. Otherwise, aliasing will occur. (a) A sine wave is sampled frequently (arrows), allowing for an accurate rendering of the signal. (b) The sampling frequency of the same wave is inadequate, leading to aliasing and the erroneous rendition of a lower frequency wave

shift will appear to be erroneously low (Fig. 1.33b) [20]. This is akin to the well-known example in movies of a rapidly spinning wheel—if the movie frame rate is not twice the frequency of the spinning wheel, aliasing occurs in which the wheel appears to be spinning slowly in the other direction. For PW Doppler, the minimum PRF needed to avoid aliasing is twice the Doppler shift frequency (fd), as given by the equation: Minimum PRF  =  2fd. When viewed in another manner, the maximum frequency shift (fd)—which equates to the maximum nonaliased velocity measurable by a PW Doppler—is equal to PRF/2. This is known as the Nyquist limit. Doppler frequency shifts below the Nyquist limit can be determined accurately; those above the Nyquist limit result in aliasing and the erroneous production of a waveform of lower frequency. Aliasing of PW Doppler is manifest as a “wrapping around” of the signal from the top to the bottom on the spectral display (Fig. 1.34). As an example, consider blood directed toward directly the transducer at 1 m/s. Using PW Doppler with a 5 MHz transmission frequency will result in a Doppler frequency shift of +6490 Hz for the returning signal. If the sample vol-

As previously mentioned, greater depth reduces PRF, thereby reducing the Nyquist limit for a given transducer. However, from Eq. 1.10 it is evident that, in addition to distance, there is an inverse relationship between transmitted ultrasound frequency and maximum detectable velocity using PW Doppler. Lower ultrasound frequencies enable detection of higher velocities than do higher frequencies, because the Doppler shifts are lower for the same reflector velocity. This is well shown on Fig. 1.35, which displays a graph of depth vs. calculated maximum detectable velocity for different transmitted ultrasound frequencies (assumed angle of insonation of 0°). In summary, to maximize PW Doppler evaluation and minimize aliasing, several techniques can be performed: • Increase the velocity scale, which increases PRF. • Adjust the spectral baseline to the top or bottom. This allocates the entire frequency range to the maximum PRF available on the machine, though directional discrimination is lost. • Use a lower frequency transducer. • If possible, decrease the depth to the sample volume. Some echocardiography machines provide a “high PRF” option for PW Doppler. This feature enables the use of a PRF higher than that allowed for the prescribed depth. This means that echoes are obtained from more than one sample volume, which in turn can lead to range ambiguity. Obviously if range ambiguity is not a concern, then CW Doppler should be used for the most accurate quantification of high velocities.

32

P. C. Wong

a

b

c

Fig. 1.34  Spectral display of aliasing by pulsed wave Doppler echocardiography in a patient with pulmonary conduit stenosis. (a) The display “wraps around” so that the Doppler tracing is cut off at the top and appears to arise from the bottom of the screen, protruding through the baseline and up into the same wave. (b) Even moving the baseline down to allocate the

5 4 Maximum 3 velocity (m/s) 2 5 MHz 1

3 MHz

7 MHz

2

4

6 Depth (cm)

8

10

Fig. 1.35  Maximum detectable velocity without aliasing using pulsed wave Doppler, as plotted vs. depth of the sample volume. Three different transducer frequencies are plotted using the Doppler equation, and assuming a 0° angle of insonation and a maximum Doppler frequency given as the pulse repetition frequency divided by 2. Note that, for any given depth, lower transducer frequencies yield higher maximum detectable velocities

entire frequency range to the signal still results in an aliased signal. This indicates that the Doppler frequency of the signal is higher than the Nyquist limit for this particular transducer (operating at 2.9 MHz). (c) When continuous wave Doppler evaluation is performed, a high velocity of over 4 m/s is measured, adequately resolved by this modality

 ombining the Spectral Doppler Modalities C With PW Doppler, precise depth information is available for localization, but there is a limit to the maximum measurable velocity due to the possibility of aliasing, particularly with deeper sample volumes. Conversely, CW Doppler has no such velocity limit, but it can become difficult to determine the precise location of a high velocity signal. In practice, the two should be used in combination: PW Doppler for localization and quantification of blood flow through most structures, CW Doppler for quantification of high velocity jets such as stenotic valves and tricuspid regurgitant jets (as demonstrated in Fig. 1.34).  voidance of Artifacts with Spectral Doppler A Proper technique is important when performing spectral Doppler evaluation. As noted previously, the angle of insonation should be as parallel as possible to the direction of blood flow. With TEE, this can become even more challenging because of the confinement of the probe to the esophagus. In such cases, the different TEE positions and views (discussed in Chap. 4, as well as multiple chapters in this textbook) should

1  Science of Ultrasound and Echocardiography

be explored to determine an optimal Doppler angle of insonation—for example, the transgastric and deep transgastric views for evaluation of the left ventricular outflow tract. Visual assessment by color flow Doppler can be very useful to optimize this evaluation. Also, it is important to obtain a highquality Doppler signal with a well-demarcated, bright, and easily visualized spectral envelope. In some instances, the signal is incomplete or weak, and increasing the gain settings results in significant artifact. “Feathering” (artifactual echo signals beyond the main spectral envelope) can also result in overestimation of the velocities [21]. During evaluation of flow across atrioventricular valves, some short, prominent valve closure signals can be mistaken for valvar regurgitation, resulting in erroneous estimation of regurgitant velocities. The operator should be well aware of all of these potential pitfalls.

 pectral Doppler for Hemodynamic S and Myocardial Assessment Spectral Doppler serves as the basis for quantitative assessment of hemodynamics by echocardiography, and it is also

33

useful for the evaluation of myocardial function. Using real-­time spectral Doppler tracings that display velocity over time, important physiologic data can be derived in regard to pressure, flow and function. These are summarized below.

 ressure Gradients and Intracardiac P Pressures This represents one of the most common and important applications of spectral Doppler. The calculation of pressure gradients is based upon Newton’s law of conservation of energy, which states that the total amount of energy within a system must remain constant. Thus, as blood flows through a stenotic orifice, kinetic energy (proportional to square of velocity) increases while potential energy decreases, and past the area of stenosis, some potential energy “recovers” while kinetic energy decreases. Using blood velocity as obtained by spectral Doppler (either PW or CW Doppler), the pressure gradient can be derived by using the Bernoulli equation:

  2 1 dv 2 2 P   V2  V1    ds 2 dt 1 Convective acceleration (kinetic) Flow acceleration (inertial)





∆P = the pressure difference across an obstructive orifice (in mm Hg) V1 = the flow velocity proximal to the obstruction V2 = the flow velocity distal to the obstruction ρ = the mass density of blood dv/dt = change in velocity over change in time ds = distance over which change in pressure occurs R = viscous resistance in blood vessel η = viscosity The first term corresponds to kinetic energy resulting from acceleration through the stenosis; the second term represents energy loss from blood flow acceleration/deceleration; the third term represents energy loss due to viscous friction. Obviously, the complete Bernoulli equation is quite complicated and requires the input of a number of different variables. However, in clinical practice, the Bernoulli equation can be simplified because generally the effects of flow acceleration and viscous friction can be ignored when evaluating flow across a discrete area of stenosis. The value of 1 ρ 2 in blood is ~4, thus yielding the modified Bernoulli equation: ΔP  =  4(V22  −  V12). In most clinical situations, V2 is much greater than V1 and therefore V1 can be discounted and V2 used by itself, yielding a simpler version of the modified Bernoulli equation often called the simplified Bernoulli equation: ΔP  =  4  V2 (V is equal to the measured spectral



 R  

(1.11)

Viscous friction (shear stress)

Doppler velocity). For example, when the maximal instantaneous velocity across a stenotic valve is 3.5 m/s, the calculated pressure gradient = 4 × (3.5)2 or 49 mm Hg. Either PW or CW Doppler can be used, though in many situations, particularly with the evaluation of stenosis, CW Doppler is needed due to the high velocities that cause aliasing with PW Doppler. A few caveats are important regarding the simplified Bernoulli equation. First, as with all Doppler evaluation, the angle of insonation should be as parallel as possible in order to obtain an accurate Doppler gradient. Second, the simplified equation becomes less accurate when there is a long, tubular stenosis (such as a Blalock-Taussig shunt). In such cases, the effect of viscous friction becomes significant, and the simplified Bernoulli equation can underestimate the pressure gradient. Third, by changing the mass density (ρ) of blood, anemia and polycythemia can have an effect upon the gradient. Finally, in some clinical situations such as hypoplastic aortic arch/coarctation of the aorta, V1 could become significant and therefore should be accounted for, i.e. the modified Bernoulli equation should be used. The modified/simplified Bernoulli equations have many uses: evaluation of pressure gradients across stenotic valves or outflow tracts, derivation of ventricular chamber pressures using the velocity across ventricular septal defects, calculation of gradients in the great arteries (e.g. coarctation, ductus

34

arteriosus), etc. In the absence of pulmonary outflow or ­pulmonary artery obstruction, a tricuspid regurgitant velocity can be used to calculate pulmonary artery pressure using the simplified Bernoulli equation. Other chamber and blood vessel pressures can be also be derived noninvasively, sometimes with the use of additional information such as arterial blood pressure or central venous pressure. Some of these hemodynamic calculations are listed in Table 1.3. Most, if not all, of these measurements can be obtained from TEE. The modified and simplified Bernoulli equations have a wide variety of applications in CHD evaluation, and their various applications will be discussed in multiple sections of this book.

Cardiac Flow Stroke volume and cardiac output can be calculated using spectral Doppler. Stroke volume is calculated from echocardiography by the equation: Q  TVI  CSA (1.12) Q = volumetric flow (stroke volume) TVI = the time velocity integral CSA  =  the cross-sectional area of the area that velocity is measured Assuming a circular cross-sectional area, the cardiac stroke volume can then be calculated from the diameter measured at the selected area. For left sided cardiac output, the aortic valve diameter is best obtained from the midesophageal aortic valve long axis view. Cross sectional area (in cm2) is then calculated by the formula π × (diameter/2)2. The time velocity integral (in cm) is calculated by manual tracing of the spectral Doppler tracing, which for the aortic valve is best obtained from a deep transgastric five-chamber or deep transgastric right ventricular outflow tract view, or a transgastric long axis view (see Chap. 4 for description of individual views). Once the stroke volume (Q) is obtained, the cardiac output can be calculated by multiplying heart rate x stroke volume, and the cardiac index derived by dividing cardiac output by body surface area. Cardiac index is given in liters/min/m2. It should be noted that this calculation should be performed when there is laminar, not turbulent, blood flow measured across the area in question. Also, the aortic valve is best used for this measurement because of its circular cross section, which does not vary significantly throughout the cardiac cycle. A similar principle of volume assessment can be applied to the calculation of aortic valve area (in the case of aortic valve stenosis), using the continuity equation. This equation is based upon the principle of conservation of mass, which stipulates that volumetric flow remains equal as it passes

P. C. Wong

from one site through another. Hence the continuity equation is given as follows: CSA1  TVI1  CSA 2  TVI 2 (1.13) In this case, the CSA1 and TVI1 are obtained from the left ventricular outflow tract below the aortic valve, using the method noted above. The spectral velocity tracing across the outflow tract is obtained by PW Doppler. The TVI2 can then be calculated from the CW Doppler spectral tracing, and from these variables, the equation can be solved for CSA2, which is the aortic valve area. It should be noted that this equation is predicated upon the assumption of a circular cross-sectional area of the left ventricular outflow tract. However, previous 3D literature has suggested that the cross-­ sectional geometry of the outflow tract is more likely elliptical than circular [22, 23]. The continuity equation serves as the basis for the calculation of valve regurgitant orifice area as measured by the proximal isovelocity surface area (PISA) method. PISA is not widely used with congenital valve disease; it is utilized to a greater extent in adult cardiology, particularly with mitral valve disease, and also with prosthetic heart valves for the calculation of valve effective orifice area [24, 25].

Myocardial Function Doppler echocardiography plays an integral role in the assessment of myocardial mechanics, particularly as regards diastolic function. Spectral Doppler assessment of ventricular filling, as well as pulmonary and systemic venous Doppler waveforms, are methods used to evaluate left ventricular and left atrial diastolic properties. In addition, other methods such as tissue Doppler imaging (also known as Doppler tissue imaging), utilize direct spectral Doppler evaluation of myocardial motion for assessment of ventricular diastolic function. This modality evaluates the low velocity, high amplitude signals of the myocardium that are filtered out by conventional spectral and color flow Doppler evaluation of blood flow (Fig. 1.36). A discussion of these methods is provided in Chap. 5. Tissue Doppler imaging can also be used for strain analysis, one of the newer methods of myocardial functional assessment. Strain measures the extent of myocardial deformation, and strain rate measures the rate of change of this deformation. Tissue Doppler imaging was the initial technique used to evaluate these parameters—strain rate was derived from the gradient of the velocity over a sampling distance, and strain obtained as the integral of this. However, the major limitation is that, like all Doppler techniques, strain could only be evaluated in one dimension—the direction along the scan line (i.e. longitudinal strain). Since myocardial strain occurs in several other directions (radial and circumferential), an alternative methodology of strain analysis has emerged to evaluate these other types of strain—that of

Systolic BP – 4 [V(PDA)]2 4 [V(early PR)]2 + CVP/RAp 4 [V(late PR)]2 + CVP/RAp Systolic BP − 4 [V(MR)]2 CVP/RAp + mean gradient across ASDa Diastolic BP − 4 [V(AR)]2

PA systolic pressure (PDA and left to right shunt present) PA mean pressure PA diastolic pressure LA pressure LA pressure (ASD and left to right shunt present) LV end diastolic pressure

Useful TEE view(s) for velocity measurement ME 4-Chamber, ME RV In-Out, ME Mod Bicaval TV ME 4-Chamber, ME RV In-Out ME AoV SAX, ME LAX UE PA, UE Ao Arch SAX ME RV In-Out, DTG RVOT ME RV In-Out, DTG RVOT ME 4-Chamber, ME 2-Chamber, ME LAX ME 4 Chamber, ME Bicaval, DTG Atr Sept ME AoV LAX; DTG 5-Chamber, DTG RVOT; TG LAX

Note: For each derived pressure, the velocity measured by spectral Doppler in shown in bold. All pressures are given in mm Hg Abbreviations: Ao aortic, ASD atrial septal defect, Atr Sept atrial septal, AR aortic regurgitation jet, AoV aortic valve, BP blood pressure, CVP central venous pressure, DTG deep transgastric, In-Out Inflow-Outflow, LA left atrium, LV left ventricle, LAX long axis, ME mid esophageal, Mod modified, MR mitral regurgitation jet, PA pulmonary artery, PDA patent ductus arteriosus, PR pulmonary regurgitation jet, RAp right atrial pressure, RV right ventricle, RVOT right ventricular outflow tract, SAX short axis, TG transgastric, TR tricuspid regurgitation jet, TV tricuspid valve, UE upper esophageal, V velocity, VSD ventricular septal defect. See Chap. 4 for a description of the individual transesophageal echocardiogram (TEE) views a Mean pressure gradient is the Bernoulli-derived pressure gradient averaged over a selected period of time (e.g. one cardiac cycle), obtained by tracing the spectral Doppler envelope

Equation 4 [V(TR)]2 + CVP/RAp Systolic BP – 4 [V(VSD)]2

Pressure RV/PA systolic pressure RV/PA systolic pressure (VSD and left to right shunt present)

Table 1.3  Noninvasive hemodynamic assessment by spectral Doppler

1  Science of Ultrasound and Echocardiography 35

36

P. C. Wong

Fig. 1.36  Tissue Doppler imaging. This tracing is taken from a transthoracic echocardiogram apical four-chamber view. The sample volume is placed at the level of the medial mitral valve annulus, and a pulsed wave spectral Doppler tracing is recorded. The E′ and A′ waves correspond to early and late diastolic filling (the E and A waves of mitral valve inflow), and the S′ wave corresponds to ventricular systole. Note the low tissue velocities (less than 10 cm/ second), much lower than those found in normal blood flow

speckle tracking. This is a 2D method that tracks a matrix of myocardial speckles that moves together with the tissue for a limited time and distance [26]. Using speckle tracking, strain can be tracked in any direction. This method has become the preferred method of strain evaluation, with tissue Doppler for strain evaluation now rarely utilized. The discussion of strain evaluation is beyond the scope of this chapter; the reader is referred to Chap. 5 and other sources that provide more in-depth discussion of deformation analysis [27–29].

B-mode beam lines

Color Flow Doppler Color flow Doppler is one of the most important echocardiographic tools available, particularly for the assessment of CHD. This modality provides a visual depiction of Doppler information for multiple reflectors and scatterers in motion— in general, these represent blood flow within the heart and arteries/veins. Doppler information is encoded as a color map and overlaid upon the corresponding B-mode images— whether 2D, 3D, or M-mode displays. Thus, real-time blood flow visualization and flow characteristics can be seen with a wide range of different physiologic situations and conditions. The acquisition of color flow data is an extension of pulseecho gray scale imaging, but instead of echo ­amplitudes, reflector velocities are determined. For each image, multiple scan lines are utilized, and multiple receiver “gates” are present for each scan line (Fig. 1.37). Ultrasound pulses are transmitted along the scan lines; these pulses are slightly longer in length to improve processing. Image (B-mode) data are

Color flow and B-mode beam lines

Fig. 1.37  Diagram of color flow Doppler. Both B-mode imaging and color flow Doppler are combined; the scan lines represent B-mode beam lines, and the small circles represent the multiple receiver “gates” located along the beam lines for color flow Doppler (these are combined color flow and B-mode beam lines). In general, only part of the imaging sector is used for color flow Doppler

acquired as outlined previously for 2D imaging. However, in contrast to B-mode imaging in which only one pulse-echo sequence is necessary per scan line, multiple pulse-echo sequences (known as a pulse packet) are sent along each beam line. Often 8–10 pulses are sent in one packet. The first

1  Science of Ultrasound and Echocardiography

returning signals, both from moving and stationary reflectors, are stored in a Doppler processing unit, in a series of registers corresponding to depth. The second set of returning signals are compared to the first set. Stationary reflectors will have identical signals and are therefore eliminated from further processing using a “stationary echo canceler”. Moving reflectors will have different signals, and the differences are used to determine reflector velocities and direction. Several techniques can be used to estimate reflector velocity, but the best known is a mathematical technique termed phase shift autocorrelation, in which the change in phase from one transmit pulse to the next is compared, and a velocity calculated. Over the course of multiple pulses, an average or mean velocity is calculated. This process is repeated for all the pulses in a packet. There is a tradeoff here: the more pulses in a packet, the better the estimates of reflector velocities but the longer the acquisition time, which slows frame rates. Once the data from all pulse packets in one scan line have been obtained, the next scan line is evaluated. This process continues in sequence for each scan line, acquiring both color flow as well as B-mode image data, until the entire color Doppler sector has been acquired (a color flow sector tends to be smaller than the underlying B-mode imaging area). Like B-mode imaging, a sweep of the sector is continually repeated and rapidly processed to achieve real-time scan rates. Nonetheless, there are tradeoffs with color flow Doppler in both temporal and spatial resolution. Frame rates for color flow Doppler are inherently lower than B-mode imaging due to the multiple pulse sequences per packet. Increased frame rates can be achieved by reducing color sector depth, and/or reducing the total number of scan lines by either narrowing the color sector or reducing scan line density. This is analogous to the options available to improve B-mode temporal resolution, as discussed previously. Spatial resolution of color flow Doppler is also less than B-mode imaging. Because of the longer spatial pulse lengths used for Doppler evaluation, axial resolution is reduced. Also, a reduced number of scan lines (to improve temporal resolution) will reduce lateral resolution. There are several ways in which information is displayed visually by color flow Doppler. Direction of flow is indicated by hue: by convention, red typically indicates flow towards the transducer, blue indicates flow away from the transducer (also known as “BART”—blue away, red towards). The brightness or saturation of the color can be used to indicate flow velocity, with brighter or whiter color indicating higher flow rates (Fig.  1.38). Some color flow mapping schemes include a variance mode in which wider variability among velocities in a single packet is indicated by a green or yellow color (Fig.  1.39a). Being a form of pulse-echo, color flow Doppler is subject to aliasing, which is displayed as color reversal or as a mosaic of multiple colors such as yellow, orange, green, etc. (Fig. 1.39a, b). With color flow Doppler,

37

the velocity scale shown is for mean velocities; nonetheless the Nyquist limit is lower, and aliasing will occur at lower velocities than PW Doppler due to the significant computational demands associated with color flow processing. It should be noted that the method of signal processing used by color flow Doppler is fundamentally different from that used for CW and PW Doppler. This is because the fast Fourier transform methods utilized for spectral evaluation are more time-consuming and, if performed for multiple scan lines and reflectors in a designated sector, the rapid processing needed for display of real-time images could not be achieved.

I mportance of Color Flow Doppler Color Doppler echocardiography plays a vital role in the noninvasive evaluation of cardiac disease. No other imaging modality provides, in real-time, the rich variety of physiologic and functional information offered by this technique. This is particularly true with CHD, in which color flow Doppler evaluation has become indispensable for echocardiographic evaluation. Its importance cannot be overstated; in a number of instances it is equally as important, if not more so, than standard 2D imaging. This is due to its exquisite sensitivity for abnormal flow velocities in many different forms of congenital cardiac pathology. There are a number of congenital cardiac defects that cannot be fully assessed until color flow Doppler evaluation is performed—in some cases the pathology is incompletely seen or not even visible by 2D imaging alone (despite the superior spatial resolution of 2D imaging). Color Doppler is an essential part of the evaluation of shunts, vascular anomalies and any pathology involving the atrioventricular and/or semilunar valves. It provides an important visual assessment of the location(s), extent, and severity of valvular stenosis or regurgitation and is very useful in directing the spectral Doppler evaluation of a stenotic/ regurgitant jet by providing the optimal location and optimal angle for spectral Doppler interrogation. Color flow Doppler also has utility for a number of congenital heart defects typified by low velocity blood flow states. Examples of this include Glenn and Fontan evaluation, and assessment of anomalous systemic and pulmonary venous pathways/connections. In these instances, the PRF is reduced (and wall filter settings can also be reduced) to decrease the velocity scale and improve color flow brightness/detectability for lower velocity reflectors. However, the lower PRF results in a decreased frame rate. In fact, color flow Doppler has become such an integral part of the echocardiographic examination that sometimes its potential shortcomings and limitations are not fully considered. As a form of Doppler evaluation, color flow Doppler is subject to the same limitations as PW Doppler. Like PW Doppler, aliasing will occur when the Nyquist limit is exceeded by the Doppler frequency shift of moving reflec-

38

P. C. Wong

Fig. 1.38 Transesophageal echocardiogram, midesophageal long axis view during systole showing color flow Doppler. The red flow represents normal flow velocity in the left ventricular outflow tract

a

b

Fig. 1.39 Transesophageal echocardiogram, midesophageal four-­ the regurgitant jet using variance mode, (b) Shows the same jet using chamber view in a patient with significant mitral insufficiency, obtained brightness mode during systole, showing different color flow Doppler maps. (a) Shows

tors, and this will be reflected in the color flow reversal or mosaic patterns described above. Lower frequency transducers enable higher PRFs and Nyquist limits. Furthermore, the color (Doppler) signals will vary depending the angle of insonation; the more perpendicular the angle, the lower the Nyquist limit. As with any Doppler modality, whenever feasible, one should strive to utilize a color Doppler angle of interrogation as parallel to the intended flow as possible. Another important reminder: it is easy to perform and record too much color flow Doppler. Because the color map is superimposed upon the real-time image, the examiner can also see the underlying anatomy while the color flow is being displayed. What can result is a study dominated by color

flow Doppler evaluation and color flow Doppler recorded clips. However, for a number of reasons, it is important to ensure that adequate B-mode imaging is performed. With color flow Doppler, the spatial and temporal resolution of the underlying B-mode images will be inferior to that of imaging alone; at times the disparity is striking, particularly the reduction in temporal resolution when color flow Doppler is activated. Also, the overlying color flow Doppler map has the potential to obscure important anatomic details, especially smaller structures. For this reason, the observer must be conscious of the need to strike a balance between adequate 2D imaging, and judicious and proper use of color flow evaluation.

1  Science of Ultrasound and Echocardiography

The other important fact to remember about color flow Doppler is that it is a map of mean velocities, and thus it is representative of blood in motion. It is not a map of blood or blood volume itself. This consideration applies particularly to valvular regurgitation, in which the color flow Doppler depiction of a regurgitant jet is often used as a visual estimate of the actual volume of the jet. However, this jet can be made to appear larger or smaller due to a number of factors. Instrument settings can change the appearance of the jet size: the jet size can appear larger when the color gain setting is increased, and also when the PRF is decreased (i.e. the Nyquist limit is lowered). If the pressure in the receiving chamber is high (e.g. the left atrium with mitral regurgitation), the pressure gradient decreases more rapidly. This can lead to lower jet velocities and a smaller color flow jet area. Furthermore, the extent and geometry of the regurgitant jet will vary depending upon whether it is central or adjacent to a cardiac boundary or wall (a “wall-hugging” jet). Even with the same regurgitant orifice, a jet next to a wall cannot entrain adjacent fluid, and therefore will appear smaller than the same jet seen in the center of the valve. Finally, color flow jets do not have the same degree of spatial resolution as the B-mode image, and often color flow jet or shunt margins are imprecise and tend to “bleed” over the 2D boundaries, thus the measurement of color flow jet diameter across, for example, a ventricular septal defect can overestimate the true defect diameter.

Audible Doppler While ultrasound frequencies are measured in millions of Hz (or MHz), the Doppler shift produced by moving structures in the body generally falls within audible frequency range. For example, if a 5  MHz signal is sent towards a reflector moving straight towards the transducer at 1.0 m/s (a typical velocity for normal blood flowing through the great arteries), the Doppler shift would be 6490 Hz (6.49 KHz), well within the human audible range of 20–20,000  Hz. Most echocardiography machines provide a sound system that can amplify and play these signals as audio. Using this signal is a useful method to guide spectral Doppler assessment—by listening for the pitch (frequency) and loudness of the signal, one can determine the optimal position for spectral Doppler evaluation, and also detect areas of turbulence/stenosis. Prior to the widespread availability of color flow Doppler, listening to the audio component served as an important part of Doppler evaluation. It was particularly helpful in screening for occult high velocity flow signals such as small ventricular septal defects that were not obvious by 2D imaging. The echocardiographer would pass a pulsed wave Doppler sample volume across the entire ventricular septum, listening for high frequency signals that might indicate a possible defect. This

39

is a technique still used by some experienced sonographers. However, for many echocardiographers, color flow Doppler has largely replaced audio because of its sensitivity and efficient evaluation of large volumes using real-time Doppler information.

Overview of the Echocardiography Machine Competent performance of an echocardiogram requires an understanding and familiarity with all of the equipment. In the case of TEE, this includes not just the transducer and associated controls on the handle, but the cardiac ultrasound machine as well. Given the time constraints of many TEE studies, particularly those performed intraoperatively, it is essential that one proceed in a rapid and efficient manner. This requires the operator to have a thorough working knowledge of all aspects of the imaging system. The layout of the echocardiography machine and its multiple controls/functions will vary with each manufacturer. Fortunately, certain features are common to every current system, and lend a certain degree of familiarity no matter what platform is used. All machines have a large high-­ resolution screen with which to view the live images. Most current machines now have “hard” keys assigned to certain unchanging functions and “soft” keys that can vary depending upon the mode of scanning performed (B-mode, color Doppler, etc.) (Fig. 1.40a). Most new machines incorporate these “soft” keys into touch screens with menus that will change and update depending upon the mode of scanning; each set of menus contains multiple options to optimize imaging and Doppler settings. There will also be a keyboard used for inputting of patient information as well as annotation/labeling of specific images; a trackball is also present and used for many functions including selection of specific images, movement of the cursor on the screen, etc. Other important features common to all echocardiography machines include a digital loop acquisition button, freeze frame/cine looping function that allows the user to scroll through a loop frame by frame (very useful for fast heart rates), as well as calipers available for making measurements directly upon the screen (Fig. 1.40b). In addition, there are specific ultrasonic features common to all echocardiographic machines, some of which are listed below. • Transmit power. Most machines allow the operator to adjust the output power, thereby increasing higher intensity pulses with greater amplitude of the transmitted echo signals. This will improve visualization of the echo signal from weaker reflectors, but will also increase the exposure of the patient to greater acoustic energy (which can produce more heat). This control is variously labeled output, power, dB, or transmit. To help gauge the potential level

40

P. C. Wong

a

b

Fig. 1.40  Photograph of a standard echocardiography machine (Philips EPIQ). The major components of an echocardiography machine are

shown in (a). (b) The control panel and touch screen are shown in more detail, along with a number of important controls detailed in the text

1  Science of Ultrasound and Echocardiography

of acoustic exposure, two standardized indices can be found on the display of the contemporary echocardiography machines from most manufacturers. It should be noted that these are calculated indices, based upon conservative assumptions, and represent “worse case” situations. The first, Thermal Index (TI), relates to the possibility of tissue heating due to absorption of ultrasound energy, and represents the ratio of acoustic power produced by the transducer to the power required to raise the temperature of tissue by one degree Celsius. There are several calculations used, depending upon whether bone is encountered along the ultrasound path; the measurement is called TIS when only soft tissue is encountered, TIB if bone is at or near the focal zone of the transducer, (e.g. fetal scans), and TIC if bone is close to the transducer. The other index, known as Mechanical Index (MI), is related to the likelihood of cavitation produced by acoustic energy. As transmit power output increases, both the TI and MI will be noted to increase. These indices have been established to help guide echocardiographers in minimizing acoustic exposure, and standardization allows them to be used and compared across a number of different echocardiography platforms, regardless of manufacturer. • Temperature sensor. Many TEE transducers have a built-in temperature sensor to monitor the patient temperature, and automatically shutoff if the temperature exceeds a predefined threshold. Nonetheless, if the probe temperature and/or local patient temperature (adjacent to the probe) is noted to increase significantly, transmit power should be reduced to decrease acoustic energy output. • Transmit frequency adjustment. As has been previously noted, broadband frequency transducers (which include TEE transducers) provide the ability for the operator to alter transmit frequency to accommodate the particular clinical imaging needs. The transducer’s default frequency is generally its center frequency, but the frequency can be increased for greater resolution (less penetration), or decreased for improved penetration (with less resolution). For TEE, given the generally excellent imaging afforded by most TEE views and windows, it is rare that significant frequency adjustment is necessary. The exception might be the deep transgastric views (see Chap. 4), in which the great distance from the transducer to certain cardiac structures could necessitate the use lower frequencies, particularly in larger patients. • Gain control. This adjusts the amplification of the received signal in order to increase or decrease the sensitivity of the instrument. It should be noted that this control, unlike transmit power, does not increase the acoustic exposure to the patient. It only increases the amplification of the received signal. There are several types of gain control. The first control is the Overall Gain Control and

41

•

•

•

•

increases amplification at all depths. The second is are the TGCs, or Time Gain Compensation controls. These are the individual slider bars that provide adjustment of receiver gain at specific depth ranges. They are used to compensate for the attenuation of signals that occur at greater depths—in other words, a “slope” of TGCs occurs, with progression from less to more gain as the depth increases. It should be noted that most machines now provide an internal TGC feature that automatically corrects for depth, obviating the need for some manual adjustment of TGCs. Also, because a brief pulse of ultrasound contains a range of frequencies, manufacturers now provide a dynamic frequency tracking feature in which the transducer responds most effectively to higher frequencies arising from shallower depths, and to lower frequencies for greater depths. This feature capitalizes on the greater penetration of lower frequency signals, and the better resolution (but lesser penetration) of the higher frequency signals. Finally, some machines also offer lateral gain control settings as well. These adjust amplification along individual beam lines (laterally), but do not adjust for depth. Dynamic range and compression. Most machines have a control that varies the range of gray scale that can be displayed. In essence, it affects the contrast and contrast resolution on the monitor—low dynamic range produces higher contrast, and vice-versa. On some scanners, reducing dynamic range also eliminates low-level echo signals, thereby producing the effect of reducing overall gain. This control is also called compression, log compression, or dynamic range. Transmit focus (focal zone). This is a feature of phased array systems and enables operator adjustment of the focal zone to various depths, based upon the timing of pulses from the individual elements. This feature helps to optimize lateral resolution. Image invert. Images can be presented with the apex of the sector at the top (the default setting for most systems) or inverted “up-down” so that the image is rotated 180° along its horizontal axis, and the apex of the sector is located at the bottom of the screen. As discussed in Chap. 4, almost all TEE views in this book are presented with the apex of the sector at the top of the screen, with the exception of the deep transgastric views, which are inverted. Of note, images can also be rotated “left-right” 180° along their vertical axis, though this is rarely (if ever) necessary, and can be very confusing. Doppler invert. Both color flow and spectral Doppler scales can be inverted so that the direction of flow can be reversed 180°. For color flow Doppler, this means that blue is flow towards the transducer, and red away from the transducer. For spectral Doppler, this means flow above the line is away from the transducer, and below the line is flow towards the transducer. It is rarely necessary to per-

42

•

•

•

•

•

•

P. C. Wong

form Doppler invert, and in fact it can be potentially confusing. Image and Doppler invert are performed independent of each other. Image freeze/cine loop. As noted, the image freeze/cine loop allows the user to “freeze” a short cine loop, which can then be scrolled backwards and forwards, frame by frame, enabling acquisition and storage of selected single images. Cine loop also enables measurements to be performed on appropriate images (these can also be stored). It should be noted that, while in freeze, the TEE transducer does not emit any ultrasound, therefore this mode should be selected to avoid heating the adjacent tissues (for example, if the TEE probe is kept in a patient’s esophagus between pre and postoperative studies). Digital loop preferences. Preferences for digital loop acquisition are generally available as a secondary menu, sometimes selected with one of the soft keys. Clip duration can be selected as a prescribed number of beats (if an ECG is present), or alternatively as a certain number of seconds. In addition, some systems provide the choice of capturing clips prospectively or retrospectively. Sector depth. The depth of scanning can be reduced, which has the effect of improving frame rates, and also increasing the size of the structures visualized. Sector size, depth, and line density. These are controls available for imaging and color flow Doppler. Decreasing sector size, depth and line density can increase frame rates. However, decreased sector size will reduce the field of view; decreased line density will reduce lateral resolution. Zoom. This is a function that allows a selected area of imaging sector to be magnified and expanded. There are two types of zoom: read and write. Read zoom takes the image data already existing in the scan converter and magnifies the existing pixels so that the selected zoom area fills the whole screen. This can be done on a frozen image. However, the existing data can appear coarse and pixelated. In contrast, write zoom allows the operator to select the zoom area first, then transducer rescans only that area and writes only the data from the zoom area to the scan converter. Theoretically, this method can result in better image detail than the read zoom function because all scan converter pixels are assigned to the zoom area. However, in practice, imaging improvements will ultimately still be limited by beam width and spatial pulse length (i.e. lateral and axial resolution). Sweep speed. The speed of certain displays such as M-mode and spectral Doppler can be varied; the usual settings are between 25 and 100 mm/sec. Slower speeds allow display of more information and variation of information over time (for example, to visualize Doppler velocity variation with respiration). Faster speeds allow more precise quantitative measurements, such as measurement of a Doppler waveform TVI.

• Reject. This is a form of electronic noise reduction in which low-level echoes and “noise” are eliminated from the display. It applies both to image as well as Doppler displays. There are of course many other controls available, some of which focus primarily upon one mode of imaging. Again, the soft keys seen will change depending upon mode selected, and there will be variation in both terminology and layout depending upon the manufacturer. It is important that the operator become very familiar with the operational aspects of whichever machine is being used.

Artifacts The nature of ultrasonic imaging is such that artifacts will inevitably be encountered. Artifacts are structures and features on an image that are either spurious, or whose displayed position does not correspond to the actual position of the object being scanned [30]. Ultrasound artifacts are can be produced by the changes in sound wave direction that occur while traveling through the body (i.e. reflection, refraction) as well as the use of reflector transmit/receive time as the proxy for reflector distance. A number of different artifacts are possible, many more than can be discussed in this section. For a complete discussion the reader is referred to several references (1–3). Nonetheless it is important for the echocardiographer to be aware of some of the more common artifacts that might be seen. A few will be discussed below.

Mirror Image Artifacts Mirror image artifacts arise from regions where an object is located next to very a strong reflector such as diaphragm. When a transmit pulse encounters the object, it is reflected back to the transducer, producing the first image. However, some sound is transmitted through the object and then continues to the interface beyond the object. The sound that returns from that interface undergoes partial reflection at the object, and this secondary echo returns back to the interface, where it is reflected again, giving rise to a secondary object that appears to be beyond the interface and appears as a mirror image. This is shown in Fig. 1.41. Mirror image artifacts can also occur with color flow Doppler. One such example is with the descending aortic long-axis view, in which a color flow signal can be seen posterior to the aorta. Mirroring can also be seen with the Doppler spectral display. This is different from the mirror image artifacts described above. A complete mirroring of the spectral tracing is seen on the opposite side of the baseline. This can be produced by a 90° angle between Doppler beam and direc-

1  Science of Ultrasound and Echocardiography

43

Fig. 1.41  Example of a mirror image artifact (white arrow) from a transesophageal echocardiogram midesophageal four-chamber view. The mirror image is seen on the opposite side of a large specular reflector, in this case, pericardium. Comet tail artifacts (yellow arrows) are also seen

Fig. 1.42  Example of a spectral Doppler mirror image artifact in a patient with a patent ductus arteriosus. In this case the transducer was nearly perpendicular to the direction of blood flow, producing the artifact. Spectral broadening is also seen

tion of blood flow, or sometimes with too high a Doppler gain setting (Fig. 1.42).

Reverberation Artifacts Reverberation artifacts occur when there is a fairly large impedance mismatch between interfaces (soft tissue-gas, fat-­muscle, etc.). If the interface is oriented perpendicular to the direction of propagation, the reflected sound creates a strong echo. Some

of this reflected sound is received by the transducer (creating an initial image), but some is also reflected from the transducer face back toward the interface, which then reflects back toward the transducer. This process can continue several times—in essence, sound “bounces” between the two surfaces. Each time, some of the returning sound is received and registered at an increased depth due to the perceived additional transmitreceive time (Fig.  1.43). Reverberation signals can be detrimental in that they can ­partially obscure actual echo signals on the display, and also produce additional “acoustic noise”.

44

P. C. Wong

Fig. 1.43  Example of a reverberation artifact in a patient undergoing transcatheter closure of an atrial septal defect. The catheter sheath in the left atrium presents a large impedance mismatch; at the points perpendicular to the ultrasound path, reverberations are seen (arrow)

Another type of reverberation artifact is when multiple internal reflections occur within a small but highly reflective object, often a metallic object such as a needle, clip, or staple. This creates a series of echoes “ringing” within the object; some of the sound returns to the transducer, resulting in a number of small bands, known as comet tails. These produce a distinctive image on the display. Comet tails can also be seen distal to a strong reflector (Fig. 1.41). Side lobes

Side Lobes and Grating Lobes There are two important artifacts associated with transducer beams. The first is side lobe artifacts, which are secondary low intensity projections of ultrasound energy adjacent to the mean beam. They result from radial vibrations of the PZE elements, as opposed to the longitudinal vibrations used to generate the main beam. Side lobes can create imaging artifacts and noise in the image that can degrade lateral ­resolution. These artifacts tend to be of low intensity, but if a side lobe encounters a highly reflective surface outside the main beam, the object will appear to be incorrectly positioned as an image along the path of the main beam (Fig. 1.44). These artifacts can be recognized by their appearance of crossing anatomic borders such as cardiac walls (Fig. 1.45). They have an inconstant appearance; with adjustment of sector depth or transducer angle, they can disappear. The other type of artifact is grating lobes, which are a byproduct of array transducers. These are multiple low inten-

Real image Artifactual image produced by side lobe

Fig. 1.44  Diagram of side lobes and the artifact that is can be produced. In this case an object encountered by one of the side lobes appears to be incorrectly positioned in the path of the main beam

1  Science of Ultrasound and Echocardiography

Fig. 1.45  Example of side lobe artifact, as shown with a transthoracic echocardiogram obtained from a standard parasternal short axis window, which was used to image the left ventricle (LV) and right ventricle (RV). This patient was known to have a central venous line in the right atrium. However on this image, the artifactual catheter tip (arrow) appeared to be located between ventricular septum and left ventricular cavity. This is due to side lobe energy giving the appearance of the catheter tip within the main beam

sity accessory beams that appear near the transducer face, but at large angles from the main beam. Ghost images can occur. These grating lobes can also degrade lateral resolution. Grating lobes can be eliminated by using very thin, closely spaced elements.

Acoustic Shadowing When an interface is encountered with significant acoustic impedance mismatching, virtually all incident sound is reflected, and none is transmitted. Thus, no imaging information is available past the interface. This leads to shadowing beyond the interface, characterized by a dark, anechoic area (Fig. 1.46). Acoustic shadowing is typically seen at the interface between blood/soft tissue and very dense objects such as metal or calcium; however, it can also be seen at soft tissue/lung interface. Whenever shadowing is encountered, other transducer positions should be attempted (if available) to circumvent the interface and visualize the area beyond it.

Digital Image Storage and DICOM For a number of reasons, proper, secure recording and storage of echocardiographic information is imperative. First, all of the images, Doppler tracings, measurements and calculations obtained by echocardiography represent patient-related information, and need to be stored permanently as part of the medical record. Second, it is vital for the different medical/

45

Fig. 1.46  Acoustic shadowing in a patient with a mechanical prosthetic aortic valve (AoV), as viewed from the transesophageal midesophageal long axis view. The metal prosthetic ring causes significant acoustic impedance mismatching, such that no sound is transmitted beyond that point and a dark, anechoic wedge of shadowing is produced (yellow arrows). Reverberation is also present. LA left atrium, LV left ventricle

surgical subspecialists to have access to the actual echocardiographic images and data, not just the reports, when making decisions about medical/surgical therapy. Third, access to the actual data from past echocardiographic studies is useful in many ways: for comparing new information to older studies, for quality control, for research and education, and for medical-legal reasons. Virtually all current echocardiographic machines and systems now store their information digitally in accordance with DICOM, the universal open standard created to ensure imaging intercompatibility among all medical imaging vendors and imaging modalities, including ultrasound, computerized tomography, magnetic resonance imaging, angiography, and radiography. It was expressly created to avoid proprietary, closed technology developed by different vendors. DICOM, which stands for Digital Imaging and COmmunications in Medicine, is not merely a file format, but rather an extensive set of rules and protocols written in a number of separate sections, and crafted to specify the terminology, rules, equipment, file formats, image compression standards, hardware, and structured reporting that facilitates exchange of medical images [31–33]. The individual sections in the DICOM standard include networking standards based on Transmission Control Protocol/Internet Protocol (TCP/IP) to allow communication and transfer of information within an imaging network, also known as a PACS (Picture Archiving and Communication Systems) network. Other sections define a syntax and commands that can be used for the exchange of information. The use of these standards allows the integration of number of different devices (printers, scanners, workstations, servers and storage devices) and imaging modalities on

46

the same PACS network. Moreover, the stored images can be read on any computer or other device equipped with DICOM reading software. A DICOM file not only contains images, but a wealth of other information including patient information, study information, calibration information for the images (allowing offline measurements and adjustments to be made), etc. To assure intercompatibility, each vendor must publish a DICOM conformance statement. The DICOM standard is regularly reviewed and updated by the National Electrical Manufacturers Association (NEMA); new supplements and sections (parts) are routinely being added to keep the standard current with technology advances in the industry. As of this writing, the DICOM standard consists of 20 parts (Table 1.4), with more parts undoubtedly to follow in the future. Further information regarding DICOM can be obtained from the DICOM website, https://www.dicomstandard.org. When recording an echocardiographic study, it is important for the operator to be aware of the need to record images carefully and adequately. In the videotape (analog) era, this was a simpler process—the recording could be started with the press of a button, and large portions of the study could be taped continuously without heed to storage space requirements. The paradigm changed with digital recording. Digital studies are superior in so many ways—improved image quality, nonlinear viewing capabilities, instantaneous accessibility from multiple networked sites, as well as the tremendous amount of additional information (aside from the images) contained in a recorded study. However, the modern digital DICOM study is not recorded continuously with the simple press of a button, but rather as a series of individual clips/loops that can be as short as one beat in length. A typical transthoracic study for CHD can vary widely between 30 and 150 separate clips/ loops, depending upon study complexity. It is an active process: the operator must regularly press the “capture” button (or its equivalent) in order to record a clip, and at times the clip length must be adjusted several times during a study. However, recording must be performed assiduously, otherwise it is easy to produce a digital recording that contains only a small number of images and therefore an inadequate record of the entire study. This can be true especially with TEE, in which a rapid study is sometimes necessary due to the limited time available, particularly in the intraoperative setting. When ongoing monitoring is performed, the operator must be selective about the information acquired so as not to accumulate repetitive images. With CHD, sweeps are often necessary to develop a threedimensional appreciation of the anatomy, and a longer capture (3–5 seconds or more) might be necessary to record the desired information [32]. With modern echocardiography machines, the captured loop/sweep can be reviewed immediately to determine whether the information is adequate recorded, or whether more clips/loops are necessary. With TEE, it is even more important to record enough sweeps and clips, as there might not be another opportunity to repeat the study.

P. C. Wong Table 1.4  DICOM standard (2020) DICOM Part 1 DICOM part 2 DICOM part 3 DICOM part 4 DICOM part 5 DICOM part 6 DICOM part 7 DICOM part 8 DICOM part 10 DICOM part 11 DICOM part 12 DICOM part 14 DICOM part 15 DICOM part 16 DICOM part 17 DICOM part 18 DICOM part 19 DICOM part 20 DICOM part 21 DICOM part 22

Introduction and Overview Conformance Information object definitions Service class specifications Data structures and encoding Data dictionary Message exchange Network communication support for message exchange Media storage and file format for data interchange Media storage application profiles Media formats and physical Media for Data Interchange Grayscale standard display function Security profiles Content mapping resource Explanatory information Web access to DICOM persistent objects (WADO) Application hosting Imaging reports using HL7 clinical document architecture Transformations between DICOM and other representations Real-time Communications

Source: DICOM/NEMA website—https://www.dicomstandard.org/ current

When a report is generated for the TEE study, it should be constructed with an eye toward readability and completeness. The report should provide an accurate, complete description and interpretation of the information contained within the images. Ideally, the report should contain essential elements including important patient demographic information, indications for the study, a description of study findings, any quantitative measurements, and a summary of pertinent positive and negative findings [34, 35].

Summary This chapter provides a summary of the many important aspects regarding the science of ultrasound and echocardiography, as well as the use and control of the echocardiographic machine. Knowledge of the different technical aspects is important for all who perform echocardiography and TEE. By understanding the important concepts presented in this chapter, the echocardiographer will have a solid foundation of knowledge, which will provide him/her with the necessary tools to optimize echocardiographic imaging and Doppler evaluation of acquired and congenital heart disease. The reader will also have an appreciation of the many strengths, as well as the limitations and potential pitfalls, associated with echocardiography.

1  Science of Ultrasound and Echocardiography

Questions and Answers 1. When ultrasound traveling through soft tissue encounters a lung filled with air, which of the following occurs? a. Reflection of the incident sound wave b. Refraction of the incident sound wave c. Interference of the incident sound wave d. Most of the incident sound wave is transmitted Answer: a Explanation: There is significant acoustic impedance mismatch between soft tissue and air. When a sound wave encounters an interface with a large impedance mismatch, most (if not all) of the energy is reflected, resulting in little ultrasonic information available distal to the interface. Refraction refers to the “bending” of an incident beam of light due to the difference between the speed of sound between the two tissues, as given by Snell’s Law (Fig. 1.5). Wave interference occurs when two waves meet. It can be constructive or destructive, depending upon whether the two waves are in phase or out of phase. 2. Which of the following affects the lateral resolution of an echocardiographic image? a. Pulse repetition frequency b. Ultrasound pulse duration c. Dynamic range d. Beam width Answer: d Explanation: Beam width is important in determining the lateral resolution of an echocardiographic image. Ultrasonic pulse duration affects axial resolution. Pulse repetition frequency affects temporal resolution as well as maximum measurable velocities by pulsed wave Doppler and color flow Doppler. Dynamic range affects contrast resolution. 3. When performing spectral Doppler evaluation of blood flow, which of the following can significantly impact the calculated velocity of blood? a. Angle of incident sound relative to direction of blood flow b. Transmitted frequency of sound c. Narrowing of imaging sector width d. Transmit power Answer: a Explanation: Note the Doppler equation below.

fD 

2 f0V cos  c

47

fD = the Doppler frequency shift = fr—f0 f0 = the transmitted frequency of sound fr = the received frequency of sound V = reflector velocity (m/s) 𝜃 = the intercept angle between the ultrasound beam and the direction of blood flow c = the velocity of sound Calculation of blood flow velocity depends upon the transmitted frequency of sound from the transducer (f0), the speed of sound in the media (c), and the angle of incident sound (θ) relative to the direction of blood flow. When the incident sound wave is completely parallel to direction of blood flow, θ = 0° and the cosine of 0° is 1. However, as θ increases from 0° (i.e. there is an increasingly greater angle of insonation), cosine θ decreases, and the calculated velocity of blood decreases compared to its true velocity. The transmitted frequency of sound from the transducer (e.g. 3 MHz, 5 MHz) does not change the calculated velocity; it is the difference between the transmitted and received frequency shift (the frequency shift) that will determine the calculated velocity. Neither the narrowing of sector width nor changing the transmit power should alter the calculated velocity of blood. 4. Which of the following is not affected by pulse repetition frequency? a. Temporal resolution for 2D imaging b. Pulsed wave Doppler c. Continuous wave Doppler d. Color flow Doppler Answer: c Explanation: Pulse repetition frequency (PRF) is dependent upon the speed of sound in a given medium; in the case of echocardiography the assumed speed of sound through soft tissue, blood and myocardium is 1540  m/s. Using the pulse echo principle of time = distance, the round-trip travel time for an ultrasound pulse is 13 μsec/cm, and it will take longer to obtain ultrasonic information from deeper objects, thereby limiting the maximum PRF. This will in turn affect the maximum frame rate for generation of a 2D image. With pulsed wave and color flow Doppler, because moving signals from a specific distance from the transducer must be sampled in order to determine an accurate velocity at that precise location, the maximum PRF for that depth plays an important role in the determining the maximum Doppler phase shift than can be accurately measured. The same holds true for color flow Doppler, which generally uses lower PRF than spectral Doppler. With continuous wave Doppler, there is constant sampling of continuously transmitted and received

48

P. C. Wong

ultrasound information, therefore there is no need for sending and receiving of specific pulses, and PRF does not apply.

d. DICOM studies can be read on any PC with standard video display software

5. All of the following maneuvers will help to minimize aliasing for pulsed wave and color flow Doppler except: a. Increase the velocity scale, which increases pulse repetition frequency (PRF) b. Adjust the spectral baseline to the top or bottom c. Decrease the depth to the sample volume d. Use a higher frequency transducer

Answer: c Explanation: The DICOM standard was developed to enable intercompatibility among different imaging vendors, and was expressly created to avoid proprietary, closed technology. It was designed for a variety of different imaging modalities including ultrasound, computerized tomography, magnetic resonance imaging, angiography, and radiography. Images from a DICOM study contain a wealth of information including patient and study information, as well as calibration information for the images (allowing offline measurements and adjustments to be made). DICOM images cannot be read by standard video programs on a PC; specialized DICOM reading software is necessary.

Answer: d Explanation: According to the Doppler equation (see Question #3 above), for any given reflector velocity lower transmitted sound will result in a lower Doppler frequency shift. For example, if an object moving towards the transducer has a velocity of 1  m/s, assuming an angle of insonance of 0°, the Doppler shift of a 2  MHz transducer is 2597 Hz, whereas the Doppler shift of a 5 MHz transducer is 6494 Hz [18]. Lower Doppler frequency shifts for any given velocity enable more adequate sampling, thereby preventing aliasing. Therefore, for any given depth, using a lower frequency transducer allows for the ability to measure higher velocities by Doppler without aliasing (see Fig. 1.35). The other maneuvers described in this question are all true, and help to increase the Nyquist limit and reduce aliasing. 6. The simplified Bernoulli equation is useful for: a. Calculation of the depth of an object from the transducer b. Calculation of the pressure gradient across a stenotic orifice c. Evaluating the degree of valvar regurgitation d. Calculation of ventricular volume Answer: b Explanation: The simplified Bernoulli equation uses the measured spectral Doppler velocity across a stenotic gradient to calculate the maximal instantaneous pressure gradient, utilizing the following formula: ΔP = 4 V2 (V is equal to the measured spectral Doppler velocity). None of the other choices uses the Doppler velocity to calculate a Doppler gradient. 7. Which of the following is true of the DICOM standard? a. It allows a medical imaging vendor to utilize its own proprietary protocols and imaging file formats, thereby ensuring a uniform standard among all of its own products. b. The DICOM standard was designed specifically for ultrasound c. Images from a DICOM study contain calibration information, enabling image adjustments

References 1. Zagzebski JA. Essentials of ultrasound physics. St. Louis: Mosby; 1996. 2. Hendee WR, Ritenour ER.  Medical imaging physics. 4th ed. New York: John Wiley & Sons; 2002. p. 512. 3. Hedrick WR, Hykes DL, Starchman DE.  Ultrasound physics and instrumentation. 4th ed. St. Louis: Mosby; 2004. 4. Gibbs V, Cole D, Sassano A. Ultrasound physics and technology: how, why and when. Edinburgh; New York: Churchill Livingstone/ Elsevier; 2009. 5. Kremkau FW. Sonography: principles and instruments. 10th ed. St Louis: Elsevier; 2021. 6. Feigenbaum H.  History of echocardiography. Feigenbaum’s echocardiography. 7th ed. Philadelphia: Wolters Kluwer Health/ Lippincott Williams & Wilkins; 2010. p. 1–8. 7. Denny MW. Air and water: the biology and physics of Life’s media. Princeton, N.J: Princeton University Press; 1993. 341 p. 8. Hendee WR, Ritenour ER.  Ultrasound waves. Medical imaging physics. 4th ed. New York: John Wiley & Sons; 2002. p. 303–16. 9. Shankar H, Pagel PS.  Potential adverse ultrasound-related biological effects: a critical review. Anesthesiology. 2011;115(5): 1109–24. 10. Gauvin A, Cloutier G, Germain M.  Principles of ultrasound. In: Denault AY, Couture P, Vegas A, Buithieu J, Tardif J-C, editors. Transesophageal echocardiography multimedia manual: a perioperative transdisciplinary approach. 2nd ed. New  York; London: Informa Healthcare; 2011. p. 1–18. 11. Badano LP, Muraru D.  Three-dimensional echocardiography. In: Lang RM, Goldsteni SA, Kronzon I, Khandheria BK, Mor-­ Avi V, editors. ASE’s comprehensive echocardiography. 2nd ed. Philadelphia: Elsevier Saunders; 2016. p. 3–10. 12. Hendee WR.  In: Ritenour ER, editor. Ultrasound transducers. Medical imaging physics. 4th ed. New York: John Wiley & Sons; 2002. p. 317–29. 13. Prager RW, Ijaz UZ, Gee AH, Treece GM, Wells PNT.  Three-­ dimensional ultrasound imaging. Proc Inst Mech Eng H J Eng Med. 2010;224(2):193–223. 14. Rabben SI. Technical principles of transthoracic three-dinensional echocardiography. In: Badano LP, Lang RM, Zamorano JL, editors. Textbook of real-time three dimensional echocardiography. London: Springer; 2011. p. 9–24.

1  Science of Ultrasound and Echocardiography 15. Salgo IS. 3D transesophageal echocardiographic technologies. In: Badano LP, Lang RM, Zamorano JL, editors. Textbook of real-­ time three dimensional echocardiography. London: Springer; 2011. p. 25–32. 16. Maslow A, Perrino AC.  Principles and technology of two-­ dimensional echocardiography. In: Perrino AC, Reeves ST, editors. A practical approach to transesophageal echocardiography. 2nd ed. Philadelphia, PA.; London: Lippincott Williams & Wilkins; 2008. p. 3–23. 17. Erb J. Basic principles of physics in echocardiographic imaging and Doppler techniques. In: Feneck RO, Kneeshaw J, Ranucci M, editors. Core topics in transesophageal echocardiography. Cambridge, UK; New York: Cambridge University Press; 2010. p. 13–33. 18. Hedrick WR, Hykes DL, Starchman DE.  Real-time ultrasound instrumentation. Ultrasound physics and instrumentation. 4th ed. Philadelphia, PA: Elsevier Mosby; 2005. p. 129–54. 19. Bulwer BE, Shernan SK, Thomas JD.  Physics of echocar diography. In: Savage RM, Aronson S, Shernan SK, editors. Comprehensive textbook of perioperative transesophageal echocardiography. 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2010. p. 3–41. 20. Evans DH, McDicken WN.  Doppler ultrasound: physics, instrumentation, and signal processing. 2nd ed. Chichester; New  York: Wiley; 2000. 21. Lopez L, Colan SD, Frommelt PC, Ensing GJ, Kendall K, Younoszai AK, et  al. Recommendations for quantification methods during the performance of a pediatric echocardiogram: a report from the pediatric measurements writing Group of the American Society of echocardiography pediatric and congenital heart disease council. J Am Soc Echocardiogr. 2010;23(5):465–95. 22. Gaspar T, Adawi S, Sachner R, Asmer I, Ganaeem M, Rubinshtein R, et al. Three-dimensional imaging of the left ventricular outflow tract: impact on aortic valve area estimation by the continuity equation. J Am Soc Echocardiogr. 2012;25:749–57. 23. Saitoh T, Shiota M, Izumo M, Gurudevan SV, Tolstrup K, Siegel RJ, et  al. Comparison of left ventricular outflow geometry and aortic valve area in patients with aortic stenosis by 2-­dimensional versus 3-dimensional echocardiography. Am J Cardiol. 2012;109(11):1626–31.

49 24. Otto CM, Bonow RO, editors. Valvular heart disease: a companion to braunwald’s heart disease. 3rd ed. Philadelphia: Saunders Elsevier; 2009. 25. Armstrong WF, Ryan T.  Hemodynamics. Feigenbaum’s echocardiography. 7th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2010. p. 217–40. 26. Voigt JU, Cvijic M. 2- and 3-dimensional myocardial strain in cardiac health and disease. JACC Cardiovasc Imaging. 2019;12(9):1849–63. 27. Armstrong WF, Ryan T. Evaluation of systolic function of the left ventricle. Feigenbaum’s Echocardiography. 7th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2010. p. 123–57. 28. Chassot P-G, Toussignant C.  Basic principles of Doppler ultrasound. In: Denault AY, Couture P, Vegas A, Buithieu J, Tardif J-C, editors. Transesophageal echocardiography multimedia manual: a perioperative transdisciplinary approach. 2nd ed. New  York; London: Informa Healthcare; 2011. p. 19–49. 29. Gorcsan J, Tanaka H. Echocardiographic assessment of myocardial strain. J Am Coll Cardiol. 2011;58(14):1401–13. 30. Zagzebski JA.  Image characteristics and artifacts. Essentials of ultrasound physics. St. Louis: Mosby; 1996. p. 123–47. 31. Thomas JD. The DICOM image formatting standard: what it means for echocardiographers. J Am Soc Echocardiogr. 1995;8(3):319–27. 32. Thomas JD, Adams DB, Devries S, Ehler D, Greenberg N, Garcia M, et al. Guidelines and recommendations for digital echocardiography. J Am Soc Echocardiogr. 2005;18(3):287–97. 33. Pianykh OS.  Digital imaging and Communications in Medicine (DICOM): a practical introduction and survival guide. Berlin: Springer; 2008. 34. Evangelista A, Flachskampf F, Lancellotti P, Badano L, Aguilar R, Monaghan M, et  al. European Association of Echocardiography recommendations for standardization of performance, digital storage and reporting of echocardiographic studies. Eur J Echocardiogr. 2008;9(4):438–48. 35. Picard MH, Adams D, Bierig SM, Dent JM, Douglas PS, Gillam LD, et  al. American Society of Echocardiography recommendations for quality echocardiography laboratory operations. J Am Soc Echocardiogr. 2011;24(1):1–10.

2

Instrumentation Ravi Managuli and Michael Brook

Abbreviations

Key Learning Objectives

2D Two-dimensional 3D Three-dimensional AI Artificial intelligence ALARA As low as reasonably achievable ASD Atrial septal defect CHD Congenital heart disease ECG Electrocardiogram ICE Intracardiac echocardiography ML Machine learning MLA Multiline acquisition MPR Multiplanar reconstruction PRF Pulse repetition frequency ROI Region of interest TEE Transesophageal echocardiography TGC Time gain compensation TTE Transthoracic echocardiography VSD Ventricular septal defect

• Describe the history of transesophageal echocardiography (TEE) instrumentation development • Recognize the different types of TEE probes available along with their dimensions and imaging characteristics • Identify different types of ultrasound modes supported and how to improve frame rate and image quality • Define pediatric cardiac applications using TEE • Define three-dimensional (3D) technology, advanced beam former technology, high frame rate imaging, machine learning that are all specifically targeted for TEE imaging

Electronic supplementary material The online version of this chapter (https://doi.org/10.1007/978-3-030-57193-1_2) contains supplementary material, which is available to authorized users. R. Managuli Affiliate Faculty, Department of Bioengineering, University of Washington, Seattle, USA Hitachi Healthcare Americas, Twinsburg, OH, USA e-mail: [email protected] M. Brook (*) Pediatric Heart Center, University of California-San Francisco, San Francisco, USA e-mail: [email protected]

Introduction While transthoracic echocardiography (TTE) is used routinely for cardiac imaging, it can suffer from limited imaging quality due to body habitus, lung disease, cardiac position/distance from the transducer, lack of available windows, and other conditions that interfere with optimal imaging. These limitations stimulated the development of transesophageal echocardiography (TEE) as an alternative method for evaluating the heart; in this modality the cardiac structures are evaluated from the esophageal and gastric positions, thereby circumventing the limitations of transthoracic imaging. In clinical cardiology practice TEE, despite its semi-invasive nature, has had a major impact on the decision-making process for patient management. In this chapter, we will review the progress of instrumentation and control technology in TEE, including its background and technological development. We will discuss current probe technology, clinical applications, and recent advances in probe development and echocardiography systems. We will also review proper care and maintenance of TEE probes, as well as adjunct TEE technology such as epicardial and intracardiac echocardiography.

© Springer Nature Switzerland AG 2021 P. C. Wong, W. C. Miller-Hance (eds.), Transesophageal Echocardiography for Pediatric and Congenital Heart Disease, https://doi.org/10.1007/978-3-030-57193-1_2

51

52

R. Managuli and M. Brook

Evolution of TEE Transthoracic imaging has always suffered from the challenges of proper imaging windows, whether it be related to body habitus, lung disease, poor windows, etc. Therefore, beginning in the 1970s, cardiologists and engineers began working to find better echocardiographic methods for defining the two-dimensional (2D) anatomy of the heart. This led to the development of transesophageal echocardiography (TEE) as an alternative method for evaluating the heart. In 1971, Side and Gosling [1] were the first to report a cardiac ultrasound from the esophagus, and they investigated the continuous-wave Doppler recordings of cardiac flow. Frazin et al. [2] in 1976 were the first Americans to describe their initial experience with a single-crystal ultrasound transducer attached to a coaxial cable that was passed into the esophagus. They demonstrated how they could obtain an M-mode recording of the heart from that position. The Japanese investigators Hisanaga et al. [3] and Matsuzaki et al. [4] were the first to report a 2D real-time scanning system, consisting of a rotating single probe element in a liquid-­ filled balloon mounted at the tip of a gastrocamera. With this system, they were able to evaluate left ventricular wall motion. The next important stage in the development of TEE transducers was the introduction of electronic sector scanners. In 1982, Schluter and Hanrath [5] from Europe invented TEE using a steerable single crystal probe, and they showed how clinically useful the technique was in adult patients. Engineers such as Souquet et al. [6] in 1982 made major contributions to the use of phased array transesophageal electronic sector scan probes. They introduced the first transesophageal 3.5  MHz electronic sector scanner phased array transducer. From this moment on, phased array scanning from the esophagus experienced a rapid evolution for the adult population. Not long afterwards, pediatric cardiologists recognized the utility of this technique. Subsequent developments in TEE included the development of multiplane (bi and varioplanes) probes by Roelandt et al. in 1992 [7] to overcome the lack of versatility associated with imaging of structures in only one transverse scan plane. The biplane probes developed had two separate ultrasound transducers with a perpendicular orientation of the two image planes: transverse and longitudinal plane [8]. Compared to single plane, which only allowed transverse scanning, the second (longitudinal) imaging plane markedly improved visualization of the more vertically oriented structures that are important in congenital heart disease (CHD), such as the superior vena cava, interatrial septum, ascending aorta, atrial appendages, right ventricular outflow tract, and left ventricular long axis [8–10]. In the 1990s, TEE transducers with color flow and Doppler capabilities were also introduced and refined. Figure 2.1 features a collection of adult multiplane and pediatric biplane TEE transducers commercially avail-

Fig. 2.1  Adult multiplane transesophageal echocardiography transducers (on the left) and pediatric biplane transducers (on the right) available 10–15 years ago

able during the 1990s. During this time, multiplane imaging devices for intraoperative use in children under 15 kg were not yet available. Even though TEE initially started with a mechanically driven single crystal transducer, the technology has evolved significantly, and TEE probes now have higher resolution, more options for image plane acquisition, and enhanced modes to better assess the cardiovascular system even in very small infants. Various technological advances have been incorporated into TEE probes, including high-frequency transducers (7–10  MHz), a full complement of Doppler modes—pulsed wave, continuous wave, and color Doppler), three-dimensional (3D) and small probes (4–7-mm diameter).

History of TEE Probes for Children Many efforts were directed toward the miniaturization of phased array transducers and the provision of higher frequencies for improved resolution so that probes could be used in very small children and even newborns or perhaps for monitoring of patients in the intensive care unit. In Japan, Aloka (now Hitachi Healthcare Business Unit) developed two pediatric single plane TEE probes (one longitudinally and the other transversely scanning). Djoa et  al. from the University Rotterdam [11] designed a 48-element pediatric single-plane TEE probe in 1989, which was commercialized by Oldelft BV (Delft, The Netherlands). In 1993 a very small 7.5-MHz neonatal TEE probe was developed by the same institution in close cooperation with Oldelft.

2 Instrumentation

The early TEE probes were limited for CHD evaluation in children due to several factors. First, the large sizes of the early TEE probes prevented their use in smaller patients (  1200  mmHg/s). (a) by permission of Mayo Foundation for Medical Education and Research. All rights reserved

b

c

Fig. 5.6  Myocardial performance index (MPI) for assessment of left ventricular global function. (a) MPI represents the ratio of isovolumic contraction time (ICT) and isovolumic relaxation time (IRT) to ventricular ejection time (ET): MPI = (ICT + IRT)/ET. (b) Midesophageal four-chamber view. The duration of ICT + IRT is measured from the cessation of mitral valve inflow to the onset of atrioventricular valve

inflow of the next cardiac cycle (interval a). (c) Deep transgastric view with pulsed wave Doppler within the left ventricular outflow tract. Ventricular ejection time is measured from the onset to cessation of LV ejection (interval b): LV MPI  =  (492  −  384)/384  =  0.28. (a) From Eidem BW et al. [101], with permission

and RV function as well as complex ventricular geometries in patients with CHD [102, 103, 105, 106]. The MPI, however, does have significant limitations. It is significantly affected by changes in loading conditions, particularly preload, and has a

paradoxical change with high filling pressures or severe semilunar valve regurgitation (“pseudo-normalization”). In addition, the combined nature of this index fails to readily discriminate between abnormalities of systolic or diastolic performance.

144

B. W. Eidem

 chocardiographic Assessment of Regional E Systolic Ventricular Function Two-Dimensional Imaging Regional ventricular function can be assessed by examining wall motion and systolic wall thickening. Transesophageal echocardiography, particularly in the intraoperative setting, is ideally suited for this purpose. Changes in ventricular wall motion typically occur during periods of decreased coronary perfusion, as can be the case during surgical interventions. These wall motion alterations are characterized by reduced systolic thickening and decreased inward endocardial excursion. In order to facilitate regional wall functional assessment, several schemes have been proposed that include specific nomenclature, a variable number of LV segmental divisions, and different methods of wall motion analysis. Two models of LV segmental division have been favored: [1] the 16-­segment LV model and [2] the 17-segment LV model. ME 4-Ch View (0˚)

ME 2-Ch View (90˚)

TEE LV 16 Segments

LA

LA

RA

The former, established in 1989 [61], represents an effort by the American Society of Echocardiography Committee on Standards and forms the basis for the guideline recommendations for performing a comprehensive intraoperative multiplane TEE examination established by the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists [108, 109]. The latter model, proposed by the American Heart Association in 2002, aimed to standardize myocardial segmentation and nomenclature for all types of cardiac imaging modalities [110]. These two models, as applied to TEE imaging, are illustrated in Figs. 5.7 and 5.8 [111]. The 16-segment model divides the LV into three levels from base to apex: basal, mid, and apical. The basal and mid levels are each divided circumferentially into six segments, and the apical level into four. The 17-segment model added the apical cap or myocardial apex at the extreme tip of the LV beyond the chamber cavity. It was also suggested that the term ‘inferior’ might be more suitable than ‘posterior’ in reference to the ventricular walls. In the most recent recommen-

0˚ Basal

6 RV Septal

5

3

2

LV 12 16

9

Lateral

LV

11 15

TG Basal SAX View (0°) Inferior 5

Posterior

Anteroseptal

Ao

1 10

7

Anteroseptal

1

LV

3 Lat eral

2 Anterior

TG Mid Pap SAX View (0°) Inferior Posterior Septal 11 10 12 RV Anteroseptal

Apical

Po ster ior 4

6 RV

LV

Mid

13

Septal

4

12 0˚ Anterior

14

ME LAX View (120˚)

LA

8

Inferior

LV 7 8 Anterior

Antero-septal

Posterior

Septal

Lateral

Inferior

Anterior

9 Lateral

Fig. 5.7  SCA/ASE 16-segment model of the left ventricle. Basal Segments: 1. Basal antero-septal, 2. Basal anterior, 3. Basal lateral, 4. Basal posterior, 5. Basal inferior, 6. Basal septal; Mid Segments: 7. Mid antero-septal, 8. Mid anterior, 9. Mid lateral, 10. Mid posterior, 11. Mid

inferior, 12. Mid septal; Apical Segments: 13. Apical anterior; 14. Apical lateral; 15. Apical inferior; 16. Apical septal. Modified from Vegas A [111], with permission from Springer

5  Functional Evaluation of the Heart

145

ME 4-Ch

ME 2-Ch View (90˚) LA

LA

RA

Inferoroseptal

12 Antero-

14

16

lateral

17

LV

10

7

Inferior

Anterior 15

120˚

13

Mid

17

ME LAX View (120˚)

LA

Basal

1

LV LV 9

0˚

4

6

3

RV V

TEE LV 17 Segments

Ao

TG Basal SAX View (0˚) Inferior InferoInfero4 lateral septal 5 3 RV LV 6 2 AnteroAntero1 lateral septal Anterior

Apical

2

5

TG Mid Pap SAX View (0°) Inferior InferoInfero8 11 10 IInferonferoAntero- septal Antero11 lateral 9 septal lateral lateral septal 14 16 16 RV LV 17 12 8 AnteroAntero7 lateral septal Anterior L LV V

Antero-septal Infero-septal Inferior Septal

Infero-lateral Antero-lateral Anterior Lateral

Apical

Fig. 5.8  AHA 17-segment model of the left ventricle. Basal Segments: 1. Basal anterior, 2. Basal antero-septal, 3. Basal infero-septal, 4. Basal inferior, 5. Basal infero-lateral, 6. Basal antero-lateral; Mid Segments: 7. Mid anterior, 8. Mid antero-septal, 9.Mid infero-septal, 10. Mid infe-

rior, 11. Mid infero-lateral, 12. Mid antero-lateral; Apical Segments: 13. Apical anterior, 14. Apical septal, 15. Apical inferior, 16. Apical lateral, 17. Apex. Modified from Vegas A [111], with permission from Springer

dations for chamber quantification it is pointed out that the 16-segment model is more suitable for assessing wall motion abnormalities (as the apical segment does not move), while the 17-segment model is more appropriate for myocardial perfusion evaluation and comparison among various imaging modalities [112]. The TG Mid Pap SAX view at the level of the papillary muscles is the suggested starting point to facilitate the qualitative evaluation of regional ventricular systolic function. Although there is significant variability in the myocardial blood supply by the coronary arteries, this cross-section allows for a prompt assessment of segmental wall function since all coronary artery territories are represented in this view (Fig. 5.9). Additional TEE cross-sections are needed to evaluate all myocardial segments as allowed by multiplanar imaging, including the ME 4-Ch, ME 2-Ch, and midesophageal long-axis (ME LAX) views (Table  5.2, Fig.  5.9) [111]. The visual assessment of wall motion should be graded as normal/ hyperkinetic, hypokinetic (reduced systolic thickening), akinetic (absent systolic thickening), dyskinetic (paradoxical systolic motion), or aneurysmal (diastolic deformation).

Table 5.2  Coronary Artery Circulation Left coronary circulation Left anterior descending (LAD) artery: (anterior, antero/infero septal walls) • Septal perforators • Diagonal branches • Posterior interventricular

Circumflex (Cx) artery: (posterior, lateral walls) • Obtuse marginal branches • Posterior interventricular

Right coronary circulation Right coronary artery (RCA): (inferior wall, RV, SA and AV nodes) • Posterior interventricular • Posterior lateral • Acute marginal Papillary muscles blood supply: • AL by two arteries (obtuse + diagonal) • PM by one artery (RCA or obtuse)

AL anterolateral, AV atrioventricular, PM posteromedial, RV right ventricle, SA sinotrial.

The feasibility of this segmental functional analysis and its utility has been reported in infants with CHD. In a prospective study of neonates undergoing an arterial switch operation for transposition of the great arteries segmental

146

B. W. Eidem Myocardial Regions Perfused by the Major Coronary Arteries

ME 4-Ch View (0˚)

ME 2-Ch View (90˚)

Obviously, the two segmental models discussed apply principally to the LV in an anatomically “normal” heart— one with situs solitus, normal segments, and atrioventricular and ventriculoarterial connections (Chap. 4). As such, there will be limited direct application of these models for a number of congenital heart defects. Nonetheless, the principles embodied in this segmental wall motion analysis—in particular, the evaluation of segmental wall kinetic motion—can be more generally applied to all forms of CHD. This facilitates a semi-quantitative, analytic assessment of wall motion and function even in hearts with very abnormal ventricular shape and morphology.

Tissue Doppler Imaging and Strain Imaging

ME LAX View (120˚)

LAD

TG Mid Pap SAX View (0˚)

Circumflex

RCA

Fig. 5.9  Myocardial regions perfused by the major coronary arteries. The figure displays the typical myocardial territories perfused by the major coronary arteries, using the midesophageal four-chamber (ME 4-Ch), midesophageal two-chamber (ME 2-Ch), midesophageal long axis (ME LAX), and transgastric mid papillary short-axis (TG Mid Pap SAX) views. Dominance depends upon which vessel (Right coronary artery or Circumflex) supplies the posterior interventricular branch. The majority of hearts (85%) are right dominant. LAD, left anterior descending, RCA, right coronary artery. Modified from Vegas A [111], with permission from Springer

wall motion was examined in the TG Mid Pap SAX and ME 4-Ch views [113]. The presence of severe wall motion abnormalities that persisted at the completion of surgery and were present in multiple segments was found to correlate with myocardial ischemia in this cohort. This highlights the importance of regional functional analysis in patients undergoing interventions that involve the coronary arteries, aortic root or any other procedures that can potentially impact coronary perfusion. Recent adult studies with 3D TEE have demonstrated the ability of this modality to quantitatively assess LV wall motion abnormalities and to improve surgical outcomes after coronary revascularization [73, 74].

The assessment of regional systolic LV function, as detailed above, has centered upon the evaluation of segmental endocardial excursion and LV wall thickening. These semi-­ quantitative methods often fail to discriminate between active and passive myocardial motion. Newer echocardiographic modalities, including tissue Doppler imaging and strain imaging, offer a potentially more quantitative and accurate approach to the assessment of regional myocardial contraction and relaxation. Tissue Doppler imaging (TDI, also known as Doppler Tissue Imaging, or DTI) has been a valuable addition to the armamentarium of the echocardiographer. By incorporating a high pass filter, tissue Doppler allows the display and quantitation of the low velocity high amplitude Doppler shifts present within the myocardium as opposed to the higher velocity lower amplitude Doppler signals more commonly measured within the blood pool (Fig. 5.10). Tissue Doppler echocardiography is less load-dependent than corresponding Doppler velocities from the blood pool and has systolic and diastolic components. These systolic velocities are heterogenous depending on ventricular wall and position. Measurement of myocardial wall velocities by TDI has been shown to be a promising modality for assessment of longitudinal systolic performance [49, 51, 114]. Studies have demonstrated significant changes in mitral annular systolic TDI velocities in adult patients with LV dysfunction and elevated filling pressures [115, 116]. These indices have also been used to identify subclinical systolic ventricular dysfunction in pediatric patients [117]. Data in children following cardiac transplantation have also been found to correlate with hemodynamic parameters [118]. Three-dimensional TEE has also been shown to accurately predict LV filling pressures as well as the need for postoperative inotropic support [119, 120]. Tissue Doppler velocities, however, cannot differentiate between active contraction and passive motion representing a major limitation when assessing regional myocardial function. Therefore, more sophisticated methods of evalu-

5  Functional Evaluation of the Heart

147

Fig. 5.10  Tissue Doppler imaging. Normal mitral annular (A), septal (B), and tricuspid annular (C) pulsed wave longitudinal Doppler tissue velocities. Note the characteristic normal pattern of a larger early diastolic velocity (E-wave) compared to late diastolic velocity (A-wave).

The S-wave is the systolic wave. ICT isovolumic contraction time, IRT isovolumic relaxation time. From Eidem BW et  al. [168], with permission

ating myocardial contraction have emerged, using the technique of deformation (strain) imaging. Regional strain represents the amount of deformation (expressed as a percentage change in length), or the fractional change in length caused by an applied force; regional strain rate corresponds to the rate of regional myocardial deformation. Both strain and strain rate can be obtained in the longitudinal, radial or circumferential directions (Fig.  5.11). The two measurements reflect different aspects of myocardial function and therefore provide complementary information. Regional strain rate can be can be calculated from the spatial gradient in myocardial velocity between two neighbouring points (measured by TDI at each point, usually 10  mm apart) within the myocardium; regional strain is then calcu-

lated by integrating the strain rate curve over time during the cardiac cycle [121]. Alternatively, regional strain can be measured directly by isolating a unique pattern of inhomogeneous acoustic reflections or “speckles” in a certain region of the myocardium, and then tracking their movement (also known as “feature tracking”) throughout the cardiac cycle (Fig.  5.12) [121, 122]. Using this method, regional strain represents the amount of deformation (expressed as a percentage change in length), or the ­fractional change in length caused by an applied force. Strain rate is then calculated as the velocity of shortening (change in distance over time). While deformation analysis can be performed by either TDI or speckle tracking, the latter technique has become much more widely adopted

148

B. W. Eidem

a

b AVC

early diastolic SR

MVO

SYS

peak sys SR

AVC DIAST

late diastolic SR

MVO

Strain Rate (sec-1)

peak sys SR

Strain Rate (sec-1)

SYS end sys strain

Shortening Lengthening

Strain (%)

Thinning

end sys strain

Fig. 5.11  Strain and strain rate imaging. Schematic representation of longitudinal (a) and radial (b) strain and strain rate imaging. In the longitudinal direction, strain represents myocardial shortening (systole) and lengthening (diastole) while strain rate represents the rate at which shortening or lengthening occurs. Similarly, radial strain represents

Strain = ∆ Length Length0

% Thickening

% Thinning Frame 1

Thickening

Frame 1 + n

Fig 5.12  Evaluation of myocardial strain by speckle tracking echocardiography. Vendor software image processing analyses patterns of ‘speckles’ and monitors them frame by frame. Myocardial contraction causes displacement of speckles, and strain is calculated by the change in length (ΔL) divided by the original length (L0), expressed as a percentage. From Gorcsan and Tanaka [121], with permission

because of its ease of use, lack of angle-dependence, independence from passive motion (described above), and application to both 2D and 3D strain evaluation [122–124]. In contrast to standard tissue Doppler velocities, these indices of myocardial deformation are not influenced by global heart motion or tethering of adjacent segments and therefore represent better indices of true regional myocardial function. Local strain values can be plotted and reported for various segments of the myocardium, or an average strain value of all the different segments (global strain) can be calculated (Fig. 5.13). Currently, global longitudinal strain is one of the most commonly used strain measurements for evaluation of both RV and LV systolic performance. Myocardial deformation imaging can also be applied by TEE in the intraoperative setting [124, 125].

DIAST

late diastolic SR

early diastolic SR Strain (%)

myocardial thickening (systole) and thinning (diastole) while strain rate represents the rate at which thickening or thinning occurs. AVC aortic valve closure, diast diastole, MVO mitral valve opening, SR strain rate, sys systole/systolic. Figures courtesy of Luc Mertens, MD

The rationale for strain evaluation is that it might be a more sensitive measure of regional and global cardiac function, and able to detect ventricular dysfunction earlier than other noninvasive measures of cardiac function, particularly in patients with abnormal ventricular geometry [126]. Studies have demonstrated regional differences in strain in adult patients after myocardial infarction [50, 127]. Measurements of radial and longitudinal strain have also been reported in normal children [128]. In addition, quantification of regional RV and LV function by strain imaging after surgical repair of tetralogy of Fallot in children demonstrated that RV deformation abnormalities are associated with electrical depolarization abnormalities or chronic pulmonary regurgitation [126, 129–132]. Further studies are needed to identify potential applications of strain imaging in the evaluation of ventricular mechanics and regional assessment of myocardial function of both the RV and LV in children [133, 134]. It is hoped that future investigations can more comprehensively address the suitability of these approaches in the perioperative setting.

 ssessment of Diastolic Ventricular Function A by Transesophageal Echocardiography Two-dimensional and particularly Doppler echocardiography have historically been essential noninvasive tools in the quantitative assessment of LV diastolic function. Abnormalities of ventricular compliance and relaxation can be demonstrated by characteristic changes in mitral inflow and pulmonary venous Doppler patterns [135, 136]. Newer methodologies, including tissue Doppler echocardiography and flow propagation velocities, enhance the ability of echocardiography to define and quantitate these adverse changes

5  Functional Evaluation of the Heart

149

a

b

c

d

Fig. 5.13  Longitudinal strain analyzed by speckle tracking echocardiography, using a standard software package. This was performed from a transesophageal echocardiogram, in which the midesophageal (ME) views of the left ventricle were utilized instead of transthoracic apical (AP) views, as follows: (a) ME long axis (AP3), (b) ME two-­ chamber (AP2), (c) ME four-chamber (AP4). The myocardial walls are divided into segments indicated by colored dots and labels. For each segment, longitudinal strain is plotted as percent longitudinal shortening (y axis) over time in one cardiac cycle (x axis), from beginning of systole to end-diastole. Longitudinal strain increases (becomes more negative) as muscle contraction occurs and eventually returns to the resting state. The nadir of each curve during systole is indicated by a

yellow dot and represents the peak systolic strain of that segment. End systolic strain is the segmental strain at aortic valve closure (AVC) time. Global longitudinal strain is the average of all curves, depicted by the white dotted line. A ‘bull’s eye’ view (d) depicts the longitudinal strain of all 17 segments of the three ME views. The color coding represents the magnitude of systolic strain, with red signaling greater (more negative) strain. ApA apical anterior, ApI apical inferior, ApL apical lateral, ApS apical septal, BA basal anterior, BAL basal anterolateral, BAS basal anteroseptal, BI basal inferior, BIL basal inferolateral, BIS basal inferoseptal, MA mid-anterior, MAL mid-anterolateral, MAS mid-­anteroseptal, MI mid-inferior, MIL mid-inferolateral, MIS mid inferoseptal. From Abuelkasem E et al. [124], with permission

150

in diastolic performance. Because diastolic dysfunction often precedes systolic dysfunction, careful assessment of diastolic function is mandatory in the noninvasive characterization and serial evaluation of patients with CHD. Noninvasive evaluation of diastolic function in normal infants and children is influenced by a variety of factors including age, heart rate, and the respiratory cycle. Reference values detailing both mitral and pulmonary venous Doppler velocities in a large cohort of normal children have been established using transthoracic imaging [137, 138]. Similar to many echocardiographic parameters, these Doppler velocities are also significantly impacted by loading conditions, making determination of diastolic dysfunction by using these parameters alone very challenging in patients with CHD. Although the evaluation of diastolic function using TEE has been reported in adult patients in the perioperative setting [139], there are no formal studies addressing this application in the pediatric age group. In addition, normal echocardiographic measures of diastolic function in adults often differ from those found in children, further inhibiting their introduction into the intraoperative setting [138]. The discussion that follows reviews general concepts of diastolic evaluation in children with the use of echocardiography and potential applications using the transesophageal modality.

Mitral Inflow Doppler Mitral inflow Doppler is readily obtained from the ME 4-Ch view and represents the diastolic pressure gradient between the left atrium (LA) and LV (Fig. 5.14). The early diastolic filling wave, or E-wave, is the dominant diastolic wave in children and young adults and represents the peak LA to LV pressure gradient at the onset of diastole. The deceleration time of the mitral E-wave reflects the time period needed for equalization of LA and LV pressures. The late diastolic filling wave, or A-wave, represents the peak pressure gradient between the LA and LV in late diastole at the onset of atrial contraction. Normal mitral inflow Doppler is characterized by a dominant E-wave, a smaller A-wave, and a ratio of Eand A-waves (E:A ratio) between 1.0 and 3.0. Normal duration of mitral deceleration time as well as isovolumic relaxation time vary with age and have been reported in both pediatric and adult populations [137, 140–143]. Mitral inflow Doppler velocities are not only impacted by changes in LV diastolic function but also by a variety of additional hemodynamic factors including age, altered loading conditions, heart rate, and changes in atrial and ventricular compliance. Interpretation of characteristic patterns of mitral inflow must be carefully evaluated with particular attention paid to the potential impact of each of these hemodynamic factors on the Doppler velocities. The earliest stage of LV diastolic dysfunction demonstrated by mitral inflow Doppler is abnormal relaxation

B. W. Eidem

(Fig. 5.14). This Doppler pattern is characteristic of normal aging in adults and represents a mild decrease in the rate of LV relaxation with continued normal LA pressure. It is characterized by a reduced E-wave velocity, increased A-wave velocity, decreased E:A ratio  3.0, and significant shortening of both mitral deceleration time and IRT (Fig. 5.14) [140]. This pattern is typically seen in patients with restrictive cardiomyopathy and may also be seen in other conditions associated with restrictive physiology (i.e., acute post-transplant setting).

Pulmonary Venous Doppler Pulmonary venous Doppler, combined with mitral inflow Doppler, provides a more comprehensive assessment of LA and LV filling pressures (Fig. 5.14) [144–146]. Transesophageal echocardiography is ideally suited to the acquisition and quantitation of pulmonary venous flows, particularly in patients with poor transthoracic windows [19, 20, 27, 147]. Pulmonary venous inflow consists of three distinct Doppler waves: a systolic wave (S-wave), a diastolic wave (D-wave), and a reversal wave that occurs with atrial contraction (Ar-wave). In normal adolescents and adults, the characteristic pattern of pulmonary venous inflow consists of a dominant S-wave, a smaller D-wave, and a small Ar-wave of low velocity and brief duration. In neonates and younger children, a dominant D-wave is often present with a similar brief low velocity, or even absent, Ar-wave. With worsening LV diastolic dysfunction, LA pressure increases leading to diminished systolic forward flow into the LA from the pulmonary veins with relatively increased dia-

5  Functional Evaluation of the Heart Fig. 5.14  Doppler patterns in diastolic dysfunction. Graphic representation of spectrum of changes in mitral and pulmonary venous inflow patterns associated with diastolic dysfunction in children. A atrial filling wave, AV atrioventricular, D pulmonary vein diastolic flow wave, E early filling wave, S pulmonary vein systolic flow wave, VAR vein atrial reversal wave. Modified from Olivier M et al. [224], with permission

151 Impaired relaxation Normal Children Velocity

E

AV valve

Venous flow

Abnormal relaxation

Adults

Decrease in compliance Mild to moderate

Severe

A

S

D

VAR

stolic forward flow resulting in a diastolic dominance of pulmonary venous inflow (Fig. 5.14). More importantly, both the velocity and duration of the pulmonary venous atrial reversal wave are increased. Pediatric and adult studies have demonstrated that an Ar-wave duration >30 milliseconds longer than the corresponding mitral A-wave duration or a ratio of pulmonary venous Ar-wave to mitral A-wave duration >1.2 is predictive of elevated LV filling pressure (Fig. 5.15) [137, 145]. Pulmonary venous flow variables as measured by TEE have been correlated with estimations of mean LA pressure in adults undergoing cardiovascular surgery [19].

Tissue Doppler Imaging Tissue Doppler imaging is particularly well suited to the quantitative evaluation of LV diastolic function and can be easily obtained by either a transthoracic or transesophageal approach. Both early (E’) and late (A’) annular diastolic velocities can be readily obtained by tissue Doppler echocardiography (Fig.  5.10). Similar to systolic tissue Doppler velocities, differences in diastolic velocities exist between [1] the subendocardium and subepicardium, [2] from cardiac base to apex, and [3] between various myocardial wall segments. Previous studies have reported an excellent correlation between the early annular diastolic mitral velocity and simultaneous invasive measures of diastolic function at cardiac catheterization [148]. Early annular diastolic velocities also appear to be less sensitive to changes in ventricular preload compared to the corresponding early transmitral ­ Doppler inflow velocity [115, 148, 149]. These diastolic tissue Doppler velocities, however, are impacted by significant alterations in preload. The influence of afterload on tissue Doppler velocities is less controversial with many studies

I

II

III and IV

documenting significant changes in systolic and diastolic annular velocities with changes in ventricular afterload [150–152]. Therefore, the clinical use of tissue Doppler velocities in patients with valvar stenoses or other etiologies of altered ventricular afterload need to be interpreted carefully in light of this limitation. Tissue Doppler velocities have been shown to be clinically helpful in the discrimination between normal and pseudonormal transmitral Doppler filling patterns [115, 153–155]. In addition to changes incurred by loading conditions, alterations in LA pressure as well as LV end-diastolic pressure also affect the early transmitral diastolic velocity. However, the corresponding tissue Doppler velocity is characteristically decreased in patients with pseudonormal filling allowing differentiation of this abnormal filling pattern from one of normal transmitral Doppler inflow. Clinical reports have demonstrated the ratio of the early transmitral inflow Doppler signal to the lateral mitral annular early diastolic velocity (mitral E/E’) to serve as a noninvasive measure of LV filling pressure. Nagueh and colleagues reported a significant correlation of mitral E/E’ with invasively measured mean pulmonary capillary wedge pressure [115], and subsequent studies have further validated this ratio and reported its applicability in a variety of hemodynamic settings mostly in adult populations. Additional novel indices of LV diastolic function utilizing tissue Doppler echocardiography have been reported that may further expand the role of this modality in the clinical evaluation of LV filling pressures [155, 156]. Tissue Doppler has also been shown to be of considerable clinical value in the differentiation of constrictive from restrictive LV filling [157–161]. Evaluation of patients with constrictive pericarditis and restrictive cardiomyopathy with 2D echocardiography and even invasive cardiac catheterization may fail to confidently distinguish these two disease states. Because the myocardium in patients with constrictive

152

B. W. Eidem

ECG

E

Velocity

A

MV

DT

S

A-d

D

PV sTVI

dTVI

PVAR-d Time

PVAR

Fig. 5.15 Mitral valve and pulmonary venous Doppler tracings. Diagram depicting mitral valve (MV) and pulmonary vein (PV) Doppler flow tracings. A atrial filling wave, A-d duration of atrial filling wave, D pulmonary vein diastolic flow wave, DT mitral deceleration time, dTVI time velocity integral of pulmonary vein diastolic flow wave, E early filling wave, ECG electrocardiogram, PVAR pulmonary vein atrial reversal wave, PVAR-d duration of pulmonary vein atrial reversal flow, S pulmonary vein systolic flow wave, sTVI time velocity integral of pulmonary vein systolic flow wave. From O’Leary PW et al. [137], with permission

pericarditis is most commonly normal, the corresponding tissue Doppler velocities are also normal. However, patients with restrictive cardiomyopathy have been shown to have significantly decreased early diastolic as well as systolic tissue Doppler velocities. Therefore, evaluation of tissue Doppler velocities allows separation of these two distinct clinical entities.

Tissue Doppler Studies in Normal Children A number of TTE studies have been performed in children to establish normal reference values of tissue Doppler velocities in this cohort [162–168]. Similar to previously published adult reports, pediatric tissue Doppler velocities vary with age, heart rate, wall location, and myocardial layer. In addi-

tion, pulsed-wave tissue Doppler velocities are also highly correlated with parameters of cardiac growth, most notably LVEDD and LV mass with the most significant changes in these velocities occurring during the first year of life (Fig. 5.16) [168]. In a published large series of infants and children, tissue Doppler velocities did not correlate significantly with other more commonly utilized measures of systolic and diastolic ventricular performance including LV fractional shortening, LV and RV MPI, and transmitral inflow Doppler [168]. This lack of correlation in part is likely due to pulsed wave tissue Doppler assessing longitudinal ventricular function while other more traditional 2D and Doppler methods assess radial and global measures of ventricular performance. Similar to previously published adult normative data, normal values for the E/E’ ratio in children have also been reported [168]. These values are also impacted by age, heart rate, ventricular wall location, LV dimension, and LV mass. Values for E/E’ are highest in neonates and decrease with advancing age primarily due to an increased E’ velocity over this time period. Data regarding simultaneous catheterization—echocardiographic measurements correlating the E/E’ ratio in children with invasive measures of LV filling pressure are limited. Two studies in children following cardiac transplantation demonstrate a poor correlation between these parameters. One study found E/E’ to be a poor predictor of simultaneously obtained, catheter-derived hemodynamic parameters in post-transplant children [169]. Another study reported that E/E’ does not correlate well with filling pressures observed after pediatric heart transplantation [118]. However, a septal E/E’ > 12 was associated with elevated pulmonary capillary wedge pressure and high-grade cellular rejection. In addition, a lateral tricuspid E/E’  >  10 was associated with elevated mean right atrial pressure. Additional studies utilizing tissue Doppler to establish normal atrioventricular electromechanical coupling intervals have also been reported [167]. The applications and clinical value of tissue Doppler echocardiography obtained by transesophageal imaging deserves ongoing evaluation [119, 120].

Color M-Mode Flow Propagation Velocity Flow propagation of early diastolic filling from the mitral annulus to the cardiac apex can be quantitated by color M-mode (Fig. 5.17). As opposed to mitral inflow Doppler, this propagation velocity has been shown to be significantly

5  Functional Evaluation of the Heart

less affected by changes in heart rate, LA pressure, and loading conditions and may therefore more accurately reflect changes in myocardial relaxation. Numerous studies have demonstrated a significant decrease in flow propagation velocity in patients with diastolic dysfunction of varying etiology [116, 170–172]. In addition, the ratio of the mitral annular Doppler tissue E-wave velocity to flow propagation velocity has also been shown to be a significant predictor of congestive heart failure and outcome in patients after myocardial infarction. This ratio of flow propagation and TDI may also be helpful in distinguishing a normal mitral inflow pattern from one of pseudonormalized mitral inflow. In a small cohort of children undergoing simultane-

153

ous cardiac catheterization and TTE, Border and colleagues demonstrated a significant positive correlation between invasively measured LV end-diastolic pressure (LVEDP) and the ratio of peak early transmitral Doppler flow velocity to flow propagation velocity (E/Vp) [173]. In another study with a small cohort of children, invasive cardiac catheterization measures of LV function were compared to simultaneously obtained color M-mode and Doppler parameters of LV performance [165]. The ratio of early diastolic mitral annular tissue Doppler velocity to flow propagation velocity (E’/Vp) correlated closely with invasively measured LVEDP while the septal E’ velocity correlated with the time constant of relaxation (Tau).

a

Fig. 5.16  Tissue Doppler velocities in children. Influence of age (a) and left ventricular end-diastolic dimension (b) on longitudinal systolic (S) and diastolic (E and A) pulsed wave tissue Doppler velocities in children. From Eidem BW et al. [168], with permission

154

B. W. Eidem

b

Fig. 5.16 (continued)

Atrial Assessment of Diastolic Function

Fig. 5.17 Color M-mode Doppler flow propagation velocity. Measurement of flow propagation velocity (Vp) from color M-mode Doppler in the assessment of left ventricular diastolic function. Vp is determined by the slope of the first clearly demarcated aliasing velocity (white line) during early left ventricular filling. In this 28  year old patient with aortic regurgitation, color M-mode during the intraoperative TEE examination demonstrated a normal Vp of 65 cm/s

One of the important newer concepts in diastology is the recognition of the integral role the atrium (and particularly the LA) plays in diastolic function. The LA acts as a volume sensor and communicates with the neurohormonal systems via secretion of natriuretic peptides and interactions with the sympathetic nervous system as well as the renin-­angiotensin-­aldosterone systems [174]. The LA manifests three principal periods of volumetric change (phasic function) that vary with the cardiac cycle. These periods include the reservoir phase (period of maximum volume expansion during ventricular systole), the conduit phase (period corresponding to early diastole when rapid decrease in atrial volume occurs), and contractile phase (period corresponding to atrial contraction, in which the minimum atrial volume is reached) (Fig.  5.18). There is significant interaction between LA and LV, and in adults,

5  Functional Evaluation of the Heart Fig. 5.18  Left atrial (LA) phasic functions and their relationship with the cardiac cycle. Mitral inflow, pulmonary venous inflow, and tissue Doppler imaging at the mitral valve annulus are shown. LA volume increases during the reservoir phase to a maximum LA volume (LAmax), followed by 2 phases of emptying—the conduit, and contractile phases—with the LA volume decreasing to the pre-atrial contraction LA volume (LApreA) and then the minimum LA volume (LAmin). Total LA stroke volume (LASV) can be divided into passive and active components. ECG electrocardiogram. From To et al. [174], reprinted by permission from Elsevier

155 LAmax

80

Passive LASV LApreA

LA Volume (mL)

LAmin Conduit

Reservoir

Active LASV

Total LASV

Time

0 Contractile

ECG

E

E A

A

Mitral Inflow Mitral Valve Closure

Mitral Valve Opening S Pulmonary Venous Inflow

Tissue Doppler Imaging

S

D

D

s’

s’

a’ e’

an increased total LA size >34  ml/m2 is now used an important criterion (along with septal e’   2.8  m/s) for determination of left sided diastolic dysfunction [136]. However, while maximum LA volume (measured by 2D and 3D echocardiography) has emerged as an important surrogate measure for LV diastolic dysfunction, LA functional changes can become evident at the earlier stages of LV diastolic dysfunction. These functional changes can be quantified by volumetric analysis such as “emptying fraction” (similar to ventricular ejection fraction) and also by longitudinal atrial strain and strain rate [174–176]. The evaluation of atrial volumes and function is just beginning to emerge for pediatric and CHD patients [177–181]; the use of TEE for evaluation of atrial assessment has yet to be established [182].

a’ e’

 chocardiographic Assessment of Right E Ventricular Function Echocardiographic assessment of RV function, either by transthoracic or transesophageal methods, has been limited due to the geometric shape of the RV. Doppler echocardiography has historically been useful in the noninvasive prediction of RV systolic and pulmonary artery pressures [183, 184]. However, quantification of RV systolic function by M-mode or 2D echocardiography has relied on the visual assessment of relative RV wall motion or semiquantitative measurements of FAC in RV dimension or volume. Newer echocardiographic modalities that have shown promise in quantifying RV function include Doppler measures of RV performance (myocardial performance index, RV dP/dt, and TDI), as well as acoustic quantification and 3D echocardiography.

156

 ight Ventricular Myocardial Performance R Index As described previously, the MPI is a Doppler-derived measure of global ventricular function that can be applied to any ventricular geometry. Studies have validated the ability of the MPI to quantitatively assess global RV function in adults and in patients with CHD [102, 105]. In addition, the MPI has demonstrated prognostic power in discriminating outcome in patients with either RV or LV failure [102–104]. However, care must be exercised in using this index in those with CHD and altered RV preload or afterload [55, 56, 185, 186]. The RV MPI has been shown to be relatively independent of changes in chronic loading conditions but the impact of acute changes in physiologic loading are significant.

Right Ventricular dP/dt Similar to the LV, the rate of pressure change over time can also be used as a measure of RV systolic function in patients with tricuspid regurgitation. Right ventricular dP/dt has been shown to correlate with invasive measures of RV performance [187–190]. RV dP/dt has also been demonstrated to be helpful in the serial assessment of RV function in children with hypoplastic left heart syndrome [189]. Similar to LV limitations with this parameter, RV dP/dt is impacted by changes in loading conditions.

Right Ventricular Tissue Doppler Imaging Tissue Doppler imaging represents one of the most quantitative modalities applied to the evaluation of RV function. Tricuspid annular motion has been shown to correlate with RV function in previous studies [163, 164, 166, 168]. Right ventricular TDI has been reported to be a reproducible noninvasive method of assessing systolic and diastolic annular motion and RV function. While impacted by both afterload and preload, data in adults and children with TDI have demonstrated these velocities to be less influenced by altered preload than corresponding mitral or tricuspid inflow Doppler. Limited data is available regarding the applications of RV TDI in CHD [191].

 coustic Quantification and Right Ventricular A Function Acoustic quantification utilizes automated border detection techniques to measure the absolute change and rate of change in RV volume. This modality has been shown to correlate

B. W. Eidem

with other invasive methods of RV functional assessment in adults with abnormalities of global RV function. Automated border methods have also shown good correlation with magnetic resonance imaging in assessing changes in RV volume and systolic function. Feasibility of acoustic quantification in the noninvasive transthoracic evaluation of RV function in normal children has also been reported [192, 193]. Ongoing investigation is needed to establish the potential of this technique for the identification and serial evaluation of RV dysfunction in children with the use of TEE.

Three-Dimensional Echocardiography and Right Ventricular Function Three-dimensional echocardiography has enabled the noninvasive evaluation of RV volume and function and has been shown to correlate very well with these parameters as obtained by cardiac magnetic resonance imaging [194–205]. It also plays a critical role in the quantitative serial assessment of RV volume and function in patients with congenital or acquired heart disease [70, 199, 206–211]. Three-­ dimensional TEE has also allowed the real time acquisition of RV volume and function during cardiac surgery and has been shown to impact surgical outcomes in these patients [75, 212–215]. Applications of real time 3D TEE to the assessment of RV volume and systolic function in adults and children continue to evolve [70, 79, 198, 216–218].

 chocardiographic Assessment of Single E Ventricular Function in Patients with Complex Congenital Heart Disease Quantitative measurement of ventricular performance in patients with functional single ventricles can be challenging. In most cases, a visual estimate of systolic function from 2D images is used. Quantitative echocardiographic assessment is limited by complex ventricular geometry often with associated abnormalities of wall motion [219–221]. Similar to novel techniques used to assess RV function, Doppler echocardiography holds promise in the evaluation of global single ventricle function [222–225]. However, only limited studies to date have addressed either dP/dt or the MPI in patients with functional single ventricles [106, 189, 226]. Data are lacking on the ability of these new Doppler indices to predict outcome in patients with complex single ventricle anatomy. Finally, 3D echocardiography also holds promise in the nongeometric assessment of ventricular volume and function but has yet to be comprehensively evaluated in patients with CHD with transesophageal imaging.

5  Functional Evaluation of the Heart

Summary The assessment of ventricular performance in CHD has been hindered by the fact that most cardiovascular anomalies are associated with abnormal ventricular geometry and altered loading conditions. Thus, the application of classic parameters developed and widely utilized in the functional assessment of the structurally normal heart are not suitable in the setting of CHD. The more recently developed echocardiographic techniques discussed throughout this chapter have provided ongoing insights into the functional abnormalities that may be present in this patient group. These modalities, initially investigated and applied with transthoracic imaging, are now allowing similar functional assessment during TEE, helping it to evolve further from a qualitative to a more quantitative approach. The techniques described in this chapter, as well as evolving techniques and technologies such as 3D imaging, give hope towards being able to provide more detailed insights into the systolic and diastolic function in CHD patients with even the most complex cardiac anatomy and geometry.

157

to display TEE images in an orientation that mimics the equivalent transthoracic cross-sections.

Case #1 Subject:  Qualitative assessment of left ventricular systolic function. Clinical History:  11  year old child referred for surgical closure of moderate sized secundum atrial septal defect.

TEE Findings: Preoperative (Videos 5.1 and 5.2) and postoperative TEE images (Videos 5.3, 5.4, 5.5) from multiple views allow for qualitative assessment of ventricular size and function in this patient. The transgastric mid papillary short axis view (inverted) as shown is Fig.  5.19a (Video 5.5) provides for M-mode interrogation and determination of LV shortening fraction (Fig. 5.19b).

Case-Based Examples

Case #2

Editor’s Note: Several of the TEE images in this section (Videos 5.2, 5.4, 5.5, 5.7, 5.11; Figs.5.19a, b, 5.20a, b, and 5.21) are displayed in a vertical orientation that completely inverted from the equivalent views presented in Chap. 4 (Structural Evaluation) and used throughout the rest of this textbook. This represents a preference by some institutions

Subject:  Assessment of right and left ventricular systolic function.

a

Fig. 5.19  Case #1. (a) Still frame demonstrating the elliptical shape of the left ventricle in a transgastric mid papillary short axis view as shown in Video 5.1. (b) Representative M-mode obtained during the TEE examination. The LV shortening fraction was 36%. Note that the orien-

Clinical History:  22 year old patient with long QT syndrome referred for surgical excision of intracardiac right ventricular lead.

b

tation of the M-mode beam with respect to the left ventricle during transesophageal/transgastric imaging may not correlate with that obtained during a transthoracic study

158

B. W. Eidem

a

b

c

d

Fig. 5.20  Case #2. (a, b) Representative M-mode images obtained during the TEE examination. The LV shortening fraction  =  [(LVEDD)  −  (LVESD)]/(LVEDD)  =  [(47  mm)  −  (24  mm)]/ (47 mm) = 49%. Figure 5.20c, d: Measurement of the left ventricular myocardial performance index. (c) A pulsed wave Doppler signal is

placed within the mitral valve inflow to obtain the mitral closure to opening interval (MV C-O, 442 ms). (d) A pulsed wave Doppler signal is placed within the left ventricular outflow tract to derive the ejection time (LVET, 342 ms). LV MPI = [(MV C-O) − (LVET)]/LVET = [(44 2 ms) − (342 ms)]/342 ms = 0.29

TEE Findings: Qualitative assessment of right and left ventricular systolic function by TEE in this case is displayed in Videos 5.6 and 5.7. Representative M-mode images for determination of LV shortening fraction are shown in Fig. 5.20a, b; Doppler tracings obtained for calculation of LV MPI are illustrated in Fig. 5.20c, d.

Case #3 Clinical History:  20 year old patient with history of tetralogy of Fallot and long-standing severe pulmonary regurgitation undergoing pulmonary valve replacement. Fig. 5.21  Case #3. M-mode echocardiogram obtained by transgastric mid papillary short axis imaging as shown in Video 5.11. The paradoxical septal wall motion secondary to the right ventricular volume overload limits this method of quantitative assessment of ventricular function in this setting

TEE Findings: Preoperative and postoperative TEE images are depicted in Videos 5.8, 5.9, 5.10, 5.11, and 5.12. These views represent suitable imaging planes for qualitative interrogation of the

5  Functional Evaluation of the Heart

159

ventricular functional abnormalities in this patient. The inverted transgastric mid papillary short-axis view (Video 5.11) is well suited for M-mode interrogation although, as shown in this case (Fig.  5.21), paradoxical septal motion may limit quantitative determination of LV systolic function.

Explanation: Measurement of LV & RV volumes is one of the hallmarks of 3D echocardiography. It has been shown to correlate closely with cardiac magnetic resonance imaging derived volumes in numerous studies. Stress-velocity index, myocardial performance index, and tissue Doppler velocities all incorporate Doppler measurements that are more readily obtained with 2D echocardiography.

Questions and Answers

4. Which of the following formulas is CORRECT for the myocardial performance index? a. [ICT + IRT]/ET b. E/E’ c. [LV EDD − LV ESD]/LVET d. [LV EDV − LV ESV]/LV EDV e. [LV EDD − LV ESD]/LV EDD

1. Which of the following echocardiographic LV measurements is MOST independent of loading conditions? a. Ejection fraction b. Stress-velocity index c. Myocardial performance index d. Fractional area change e. Tissue Doppler velocities Answer: b Explanation: The relationship between velocity of circumferential fiber shortening and end-systolic wall stress is independent of heart rate and incorporates afterload making it the most load independent measure of ventricular contractility. Ejection fraction, myocardial performance index, fractional area change, and tissue Doppler velocities are all significantly impacted by both preload and afterload. 2. Which of the following measurements is the BEST estimate of LV filling pressure? a. E/E’ ratio b. E/A ratio c. Pulmonary venous S/D ratio d. Lateral wall E’ velocity e. dP/dt Answer: a Explanation: The ratio of the early wave of mitral inflow Doppler to the early annular tissue Doppler velocity (E/E’) has been shown in many studies to correlate with invasive measures of LV filling pressure. Mitral E/A ratio, lateral E’ tissue Doppler velocity, and pulmonary venous systolic to diastolic wave velocity ratio (S/D ratio) are markers for diastolic function but do not correlate with filling pressure. LV dP/dt is a measure of systolic function. 3. Which of the following would be BEST obtained by 3D echocardiography? a. LV stress-velocity index b. LV myocardial performance index c. LV end-systolic and end-diastolic volume d. LV lateral wall tissue Doppler velocities e. RV lateral wall tissue Doppler velocities Answer: c

Answer: a Explanation: The myocardial performance index is a ratio of total time spent in isovolumic activity (isovolumic contraction and relaxation times) divided by the time spent in ventricular ejection. It is a measure of global ventricular function incorporating both systolic (ICT and ET) and diastolic (IRT) components. E/E’ is a measure of ventricular filling pressure. [LV EDD − LV ESD]/LVET is the measurement of circumferential fiber shortening while [LV EDD − LV ESD]/LV EDD and [LV EDV − LV ESV]/LV EDV are measures of ejection fraction. 5. Which of the following is a measurement of global left ventricular function that incorporates both systolic and diastolic components? a. Ejection fraction b. Velocity of circumferential fiber shortening c. Myocardial performance index d. dP/dt e. Longitudinal strain Answer: c Explanation: The myocardial performance index is a measure of global ventricular function with both systolic and diastolic components. Ejection fraction, velocity of circumferential fiber shortening, dP/dt, and longitudinal strain are measures of systolic ventricular function.

References 1. Cyran SE, Kimball TR, Meyer RA, Bailey WW, Lowe E, Balisteri WF, et al. Efficacy of intraoperative transesophageal echocardiography in children with congenital heart disease. Am J Cardiol. 1989;63(9):594–8. 2. Ritter SB.  Transesophageal echocardiography in children: new peephole to the heart. J Am Coll Cardiol. 1990;16(2):447–50. 3. Stümper OF, Elzenga NJ, Hess J, Sutherland GR. Transesophageal echocardiography in children with congenital heart disease: an initial experience. J Am Coll Cardiol. 1990;16(2):433–41.

160 4. Ungerleider RM, Greeley WJ, Sheikh KH, Philips J, Pearce FB, Kern FH, et al. Routine use of intraoperative epicardial echocardiography and Doppler color flow imaging to guide and evaluate repair of congenital heart lesions. A prospective study. J Thorac Cardiovasc Surg. 1990;100(2):297–309. 5. Fyfe DA, Kline CH, Sade RM, Greene CA, Gillette PC.  The utility of transesophageal echocardiography during and after Fontan operations in small children. Am Heart J. 1991;122(5): 1403–15. 6. Stevenson JG, Sorensen GK, Gartman DM, Hall DG, Rittenhouse EA. Transesophageal echocardiography during repair of congenital cardiac defects: identification of residual problems necessitating reoperation. J Am Soc Echocardiogr. 1993;6(4):356–65. 7. Stevenson JG.  Role of intraoperative transesophageal echocardiography during repair of congenital cardiac defects. Acta Paediatr Suppl. 1995;410:23–33. 8. Ninomiya J, Yamauchi H, Hosaka H, Ishii Y, Terada K, Sugimoto T, et al. Continuous transoesophageal echocardiography monitoring during weaning from cardiopulmonary bypass in children. Cardiovasc Surg. 1997;5(1):129–33. 9. Rice MJ, McDonald RW, Li X, Shen I, Ungerleider RM, Sahn DJ. New technology and methodologies for intraoperative, perioperative, and intraprocedural monitoring of surgical and catheter interventions for congenital heart disease. Echocardiography. 2002;19(8):725–34. 10. Stumper O, Witsenburg M, Sutherland GR, Cromme-Dijkhuis A, Godman MJ, Hess J.  Transesophageal echocardiographic monitoring of interventional cardiac catheterization in children. J Am Coll Cardiol. 1991;18(6):1506–14. 11. Tumbarello R, Sanna A, Cardu G, Bande A, Napoleone A, Bini RM.  Usefulness of transesophageal echocardiography in the pediatric catheterization laboratory. Am J Cardiol. 1993;71(15):1321–5. 12. Ludomirsky A.  The use of echocardiography in pediatric interventional cardiac catheterization procedures. J Interv Cardiol. 1995;8(5):569–78. 13. Rigby ML. Transoesophageal echocardiography during interventional cardiac catheterisation in congenital heart disease. Heart. 2001;86(Suppl 2):II23–9. 14. Simon P, Mohl W.  Intraoperative echocardiographic assessment of global and regional myocardial function. Echocardiography. 1990;7(3):333–41. 15. Skiles JA, Griffin BP.  Transesophageal echocardiographic (TEE) evaluation of ventricular function. Cardiol Clin. 2000;18(4):681–97. 16. Puchalski MD, Lui GK, Miller-Hance WC, Brook MM, Young LT, Bhat A, et al. Guidelines for performing a comprehensive transesophageal echocardiographic examination in children and all patients with congenital heart disease: recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019;32(2):173–215. 17. Abel MD, Nishimura RA, Callahan MJ, Rehder K, Ilstrup DM, Tajik AJ.  Evaluation of intraoperative transesophageal two-­ dimensional echocardiography. Anesthesiology. 1987;66(1): 64–8. 18. Nishimura RA, Abel MD, Housmans PR, Warnes CA, Tajik AJ. Mitral flow velocity curves as a function of different loading conditions: evaluation by intraoperative transesophageal Doppler echocardiography. J Am Soc Echocardiogr. 1989;2(2):79–87. 19. Kuecherer HF, Muhiudeen IA, Kusumoto FM, Lee E, Moulinier LE, Cahalan MK, et  al. Estimation of mean left atrial pressure from transesophageal pulsed Doppler echocardiography of pulmonary venous flow. Circulation. 1990;82(4):1127–39. 20. Kuecherer HF, Kusumoto F, Muhiudeen IA, Cahalan MK, Schiller NB.  Pulmonary venous flow patterns by transesophageal pulsed Doppler echocardiography: relation to parameters

B. W. Eidem of left ventricular systolic and diastolic function. Am Heart J. 1991;122(6):1683–93. 21. Muhiudeen IA, Kuecherer HF, Lee E, Cahalan MK, Schiller NB.  Intraoperative estimation of cardiac output by transesophageal pulsed Doppler echocardiography. Anesthesiology. 1991;74(1):9–14. 22. Savino JS, Troianos CA, Aukburg S, Weiss R, Reichek N.  Measurement of pulmonary blood flow with transesophageal two-dimensional and Doppler echocardiography. Anesthesiology. 1991;75(3):445–51. 23. Gorcsan J 3rd, Diana P, Ball BA, Hattler BG. Intraoperative determination of cardiac output by transesophageal continuous wave Doppler. Am Heart J. 1992;123(1):171–6. 24. Smith MD, MacPhail B, Harrison MR, Lenhoff SJ, DeMaria AN.  Value and limitations of transesophageal echocardiography in determination of left ventricular volumes and ejection fraction. J Am Coll Cardiol. 1992;19(6):1213–22. 25. Stoddard MF, Dillon S, Peters G, Kupersmith J. Left ventricular ejection fraction is increased during transesophageal echocardiography in patients with impaired ventricular function. Am Heart J. 1992;123(4 Pt 1):1005–10. 26. Doerr HK, Quinones MA, Zoghbi WA.  Accurate determination of left ventricular ejection fraction by transesophageal echocardiography with a nonvolumetric method. J Am Soc Echocardiogr. 1993;6(5):476–81. 27. Kuecherer HF, Foster E. Hemodynamics by transesophageal echocardiography. Cardiol Clin. 1993;11(3):475–87. 28. Rafferty T, Durkin M, Harris S, Elefteriades J, Hines R, Prokop E, et  al. Transesophageal two-dimensional echocardiographic analysis of right ventricular systolic performance indices during coronary artery bypass grafting. J Cardiothorac Vasc Anesth. 1993;7(2):160–6. 29. Sutton DC, Cahalan MK.  Intraoperative assessment of left ventricular function with transesophageal echocardiography. Cardiol Clin. 1993;11(3):389–98. 30. Darmon PL, Hillel Z, Mogtader A, Mindich B, Thys D. Cardiac output by transesophageal echocardiography using continuous-­ wave Doppler across the aortic valve. Anesthesiology. 1994;80(4):796–805. 31. Pu M, Griffin BP, Vandervoort PM, Leung DY, Cosgrove DM 3rd, Thomas JD. Intraoperative validation of mitral inflow determination by transesophageal echocardiography: comparison of single-­ plane, biplane and thermodilution techniques. J Am Coll Cardiol. 1995;26(4):1047–53. 32. Hozumi T, Yoshikawa J.  Three-dimensional echocardiography using a muliplane transesophageal probe: the clinical applications. Echocardiography. 2000;17(8):757–64. 33. Troianos CA, Porembka DT. Assessment of left ventricular function and hemodynamics with transesophageal echocardiography. Crit Care Clin. 1996;12(2):253–72. 34. Kuhl HP, Franke A, Frielingsdorf J, Flaskamp C, Krebs W, Flachskampf FA, et  al. Determination of left ventricular mass and circumferential wall thickness by three-dimensional reconstruction: in  vitro validation of a new method that uses a multiplane transesophageal transducer. J Am Soc Echocardiogr. 1997;10(2):107–19. 35. Kuhl HP, Franke A, Janssens U, Merx M, Graf J, Krebs W, et al. Three-dimensional echocardiographic determination of left ventricular volumes and function by multiplane transesophageal transducer: dynamic in  vitro validation and in  vivo comparison with angiography and thermodilution. J Am Soc Echocardiogr. 1998;11(12):1113–24. 36. Ochiai Y, Morita S, Tanoue Y, Kawachi Y, Tominaga R, Yasui H.  Use of transesophageal echocardiography for postoperative evaluation of right ventricular function. Ann Thorac Surg. 1999;67(1):146–52.

5  Functional Evaluation of the Heart 37. Poelaert J, Schmidt C, Van Aken H, Hinder F, Mollhoff T, Loick HM.  A comparison of transoesophageal echocardiographic Doppler across the aortic valve and the thermodilution technique for estimating cardiac output. Anaesthesia. 1999;54(2):128–36. 38. Kubota H, Furuse A, Kotsuka Y, Ninomiya M, Miyaji K, Endo M, et al. Cardiac function evaluated by transesophageal echocardiography during cardiopulmonary bypass. Jpn J Thorac Cardiovasc Surg. 2000;48(5):261–6. 39. Schiller NB. Hemodynamics derived from transesophageal echocardiography (TEE). Cardiol Clin. 2000;18(4):699–709. 40. Simmons LA, Weidemann F, Sutherland GR, D’Hooge J, Bijnens B, Sergeant P, et  al. Doppler tissue velocity, strain, and strain rate imaging with transesophageal echocardiography in the operating room: a feasibility study. J Am Soc Echocardiogr. 2002;15(8):768–76. 41. Swaminathan M, Phillips-Bute BG, Mathew JP.  An assessment of two different methods of left ventricular ejection time measurement by transesophageal echocardiography. Anesth Analg. 2003;97(3):642–7. 42. Poelaert JI, Schupfer G. Hemodynamic monitoring utilizing transesophageal echocardiography: the relationships among pressure, flow, and function. Chest. 2005;127(1):379–90. 43. Chen C, Rodriguez L, Guerrero JL, Marshall S, Levine RA, Weyman AE, et  al. Noninvasive estimation of the instantaneous first derivative of left ventricular pressure using continuous-wave Doppler echocardiography. Circulation. 1991;83(6):2101–10. 44. Greim CA, Roewer N, Laux G, Schulte am Esch J. On-line estimation of left ventricular stroke volume using transoesophageal echocardiography and acoustic quantification. Br J Anaesth. 1996;77(3):365–9. 45. Rhodes J, Marx GR, Tardif JC, Romero BA, Robinson A, Acar P, et  al. Evaluation of ventricular dP/dt before and after open heart surgery using transesophageal echocardiography. Echocardiography. 1997;14(1):15–22. 46. Declerck C, Hillel Z, Shih H, Kuroda M, Connery CP, Thys DM. A comparison of left ventricular performance indices measured by transesophageal echocardiography with automated border detection. Anesthesiology. 1998;89(2):341–9. 47. Kotoh K, Watanabe G, Ueyama K, Uozaki M, Suzuki M, Misaki T, et  al. On-line assessment of regional ventricular wall motion by transesophageal echocardiography with color kinesis during minimally invasive coronary artery bypass grafting. J Thorac Cardiovasc Surg. 1999;117(5):912–7. 48. Vermes E, Houel R, Simon M, Le Besnerais P, Loisance D. Doppler tissue imaging to predict myocardial recovery during mechanical circulatory support. Ann Thorac Surg. 2000;70(6): 2149–51. 49. Skarvan K, Filipovic M, Wang J, Brett W, Seeberger M. Use of myocardial tissue Doppler imaging for intraoperative monitoring of left ventricular function. Br J Anaesth. 2003;91(4): 473–80. 50. Skulstad H, Andersen K, Edvardsen T, Rein KA, Tonnessen TI, Hol PK, et al. Detection of ischemia and new insight into left ventricular physiology by strain Doppler and tissue velocity imaging: assessment during coronary bypass operation of the beating heart. J Am Soc Echocardiogr. 2004;17(12):1225–33. 51. David JS, Tousignant CP, Bowry R.  Tricuspid annular velocity in patients undergoing cardiac operation using transesophageal echocardiography. J Am Soc Echocardiogr. 2006;19(3): 329–34. 52. Borow KM, Neumann A, Marcus RH, Sareli P, Lang RM. Effects of simultaneous alterations in preload and afterload on measurements of left ventricular contractility in patients with dilated cardiomyopathy: comparisons of ejection phase, isovolumetric and end-systolic force-velocity indexes. J Am Coll Cardiol. 1992;20(4):787–95.

161 53. Kimball TR, Daniels SR, Loggie JM, Khoury P, Meyer RA. Relation of left ventricular mass, preload, afterload and contractility in pediatric patients with essential hypertension. J Am Coll Cardiol. 1993;21(4):997–1001. 54. Rowland DG, Gutgesell HP.  Noninvasive assessment of myocardial contractility, preload, and afterload in healthy newborn infants. Am J Cardiol. 1995;75(12):818–21. 55. Kjaergaard J, Snyder EM, Hassager C, Oh JK, Johnson BD. Impact of preload and afterload on global and regional right ventricular function and pressure: a quantitative echocardiography study. J Am Soc Echocardiogr. 2006;19(5):515–21. 56. Ozdemir K, Balci S, Duzenli MA, Can I, Yazici M, Aygul N, et  al. Effect of preload and heart rate on the doppler and tissue doppler-derived myocardial performance index. Clin Cardiol. 2007;30(7):342–8. 57. Bailey JM, Shanewise JS, Kikura M, Sharma S. A comparison of transesophageal and transthoracic echocardiographic assessment of left ventricular function in pediatric patients with congenital heart disease. J Cardiothorac Vasc Anesth. 1995;9(6):665–9. 58. Silverman NH, Ports TA, Snider AR, Schiller NB, Carlsson E, Heilbron DC. Determination of left ventricular volume in children: echocardiographic and angiographic comparisons. Circulation. 1980;62(3):548–57. 59. Quinones MA, Waggoner AD, Reduto LA, Nelson JG, Young JB, Winters WL Jr, et al. A new, simplified and accurate method for determining ejection fraction with two-dimensional echocardiography. Circulation. 1981;64(4):744–53. 60. Mercier JC, DiSessa TG, Jarmakani JM, Nakanishi T, Hiraishi S, Isabel-Jones J, et al. Two-dimensional echocardiographic assessment of left ventricular volumes and ejection fraction in children. Circulation. 1982;65(5):962–9. 61. Schiller NB, Shah PM, Crawford M, DeMaria A, Devereux R, Feigenbaum H, et al. Recommendations for quantitation of the left ventricle by two-dimensional echocardiography. American Society of Echocardiography Committee on Standards, Subcommittee on Quantitation of Two-Dimensional Echocardiograms. J Am Soc Echocardiogr. 1989;2(5):358–67. 62. Harrison MR, Clifton GD, Berk MR, DeMaria AN.  Effect of blood pressure and afterload on Doppler echocardiographic measurements of left ventricular systolic function in normal subjects. Am J Cardiol. 1989;64(14):905–8. 63. Bashein G, Sheehan FH, Nessly ML, Detmer PR, Martin RW.  Three-dimensional transesophageal echocardiography for depiction of regional left-ventricular performance: initial results and future directions. Int J Card Imaging. 1993;9(2): 121–31. 64. Keller AM.  Positional localization: three-dimensional transthoracic echocardiographic techniques for the measurement of cardiac mass, volume, and function. Echocardiography. 2000;17(8):745–8. 65. Mizelle KM, Rice MJ, Sahn DJ.  Clinical use of real-time three-dimensional echocardiography in pediatric cardiology. Echocardiography. 2000;17(8):787–90. 66. Azran MS, Kwong R, Chen FY, Shernan SK.  A potential use for intraoperative three-dimensional transesophageal echocardiography in predicting left ventricular chamber dimensions and ejection fraction after aneurysm resection. Anesth Analg. 2010;111(6):1362–5. 67. Cowie B, Kluger R, Kalpokas M.  Left ventricular volume and ejection fraction assessment with transoesophageal echocardiography: 2D vs 3D imaging. Br J Anaesth. 2013;110(2): 201–6. 68. Grossgasteiger M, Hien MD, Graser B, Rauch H, Gondan M, Motsch J, et al. Assessment of left ventricular size and function during cardiac surgery. An intraoperative evaluation of six two-­ dimensional echocardiographic methods with real time three-­

162 dimensional echocardiography as a reference. Echocardiography. 2013;30(6):672–81. 69. Meris A, Santambrogio L, Casso G, Mauri R, Engeler A, Cassina T.  Intraoperative three-dimensional versus two-dimensional echocardiography for left ventricular assessment. Anesth Analg. 2014;118(4):711–20. 70. Simpson J, Lopez L, Acar P, Friedberg MK, Khoo NS, Ko HH, et  al. Three-dimensional echocardiography in congenital heart disease: an expert consensus document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30(1):1–27. 71. Jungwirth B, Mackensen GB.  Real-time 3-dimensional echocardiography in the operating room. Semin Cardiothorac Vasc Anesth. 2008;12(4):248–64. 72. Fischer GW, Anyanwu AC, Adams DH. Change in surgical management as a consequence of real-time 3D TEE: assessment of left ventricular function. Semin Cardiothorac Vasc Anesth. 2009;13(4):238–40. 73. Aggarwal N, Unnikrishnan KP, Biswas I, Karunakaran J, Suneel PR. Intraoperative assessment of transient and persistent regional left ventricular wall motion abnormalities in patients undergoing coronary revascularization surgery using real time three-­ dimensional transesophageal echocardiography: a prospective observational study. Echocardiography. 2017;34(11):1649–59. 74. Karnwal A, Kakazu CZ, Shah S, Omari B, Arora CD. Utilization of intraoperative real-time three-dimensional transoesophageal echocardiography to objectively assess improvement in synchronization and regional wall motion after coronary reperfusion. J Clin Diagn Res. 2017;11(3):TD01–TD2. 75. Turton EW, Ender J.  Role of 3D echocardiography in cardiac surgery: strengths and limitations. Curr Anesthesiol Rep. 2017;7(3):291–8. 76. Simpson JM, Miller O.  Three-dimensional echocardiography in congenital heart disease. Arch Cardiovasc Dis. 2011;104(1):45–56. 77. Shirali GS.  Three-dimensional echocardiography in congenital heart disease. Echocardiography. 2012;29(2):242–8. 78. Zhang L, Xie M, Balluz R, Ge S.  Real time three-dimensional echocardiography for evaluation of congenital heart defects: state of the art. Echocardiography. 2012;29(2):232–41. 79. Simpson JM.  Three-dimensional echocardiography in congenital heart disease: the next steps. Arch Cardiovasc Dis. 2016;109(2):81–3. 80. Perez JE, Waggoner AD, Barzilai B, Melton HE Jr, Miller JG, Sobel BE.  On-line assessment of ventricular function by automatic boundary detection and ultrasonic backscatter imaging. J Am Coll Cardiol. 1992;19(2):313–20. 81. Gorcsan J 3rd, Romand JA, Mandarino WA, Deneault LG, Pinsky MR.  Assessment of left ventricular performance by on-line pressure-­area relations using echocardiographic automated border detection. J Am Coll Cardiol. 1994;23(1):242–52. 82. Gorcsan J 3rd, Denault A, Mandarino WA, Pinsky MR.  Left ventricular pressure-volume relations with transesophageal echocardiographic automated border detection: comparison with conductance-catheter technique. Am Heart J. 1996;131(3): 544–52. 83. Liu N, Darmon PL, Saada M, Catoire P, Rosso J, Berger G, et  al. Comparison between radionuclide ejection fraction and fractional area changes derived from transesophageal echocardiography using automated border detection. Anesthesiology. 1996;85(3):468–74. 84. Chandra S, Bahl VK, Reddy SC, Bhargava B, Malhotra A, Wasir HS.  Comparison of echocardiographic acoustic quantification system and radionuclide ventriculography for estimating left ventricular ejection fraction: validation in patients without regional wall motion abnormalities. Am Heart J. 1997;133(3):359–63.

B. W. Eidem 85. Denault AY, Gorcsan J 3rd, Mandarino WA, Kancel MJ, Pinsky MR. Left ventricular performance assessed by echocardiographic automated border detection and arterial pressure. Am J Phys. 1997;272(1 Pt 2):H138–47. 86. Schmidlin D, Aschkenasy S, Vogt PR, Schmidli J, Jenni R, Schmid ER.  Left ventricular pressure-area relations as assessed by transoesophageal echocardiographic automated border detection: comparison with conductance catheter technique in cardiac surgical patients. Br J Anaesth. 2000;85(3):379–88. 87. Fisher EA, DuBrow IW, Hastreiter AR.  Comparison of ejection phase indices of left ventricular performance in infants and children. Circulation. 1975;52(5):916–25. 88. Igarashi H, Shiraishi H, Endoh H, Yanagisawa M. Left ventricular contractile state in preterm infants: relation between wall stress and velocity of circumferential fiber shortening. Am Heart J. 1994;127(5):1336–40. 89. Tynan M, Reid DS, Hunter S, Kaye HH, Osme S, Urquhart W, et  al. Ejection phase indices of left ventricular performance in infants, children, and adults. Br Heart J. 1975;37(2):196–202. 90. Gutgesell HP, Paquet M, Duff DF, McNamara DG. Evaluation of left ventricular size and function by echocardiography. Results in normal children. Circulation. 1977;56(3):457–62. 91. Henry WL, Ware J, Gardin JM, Hepner SI, McKay J, Weiner M. Echocardiographic measurements in normal subjects. Growth-­ related changes that occur between infancy and early adulthood. Circulation. 1978;57(2):278–85. 92. Ruschhaupt DG, Sodt PC, Hutcheon NA, Arcilla RA. Estimation of circumferential fiber shortening velocity by echocardiography. J Am Coll Cardiol. 1983;2(1):77–84. 93. Greim CA, Roewer N, Schulte am Esch J. Assessment of changes in left ventricular wall stress from the end-systolic pressure-area product. Br J Anaesth. 1995;75(5):583–7. 94. Colan SD, Borow KM, Neumann A.  Left ventricular end-systolic wall stress-velocity of fiber shortening relation: a load-­ independent index of myocardial contractility. J Am Coll Cardiol. 1984;4(4):715–24. 95. Royse CF, Connelly KA, MacLaren G, Royse AG.  Evaluation of echocardiography indices of systolic function: a comparative study using pressure-volume loops in patients undergoing coronary artery bypass surgery. Anaesthesia. 2007;62(2):109–16. 96. Tei C. New non-invasive index for combined systolic and diastolic ventricular function. J Cardiol. 1995;26(2):135–6. 97. Tei C, Ling LH, Hodge DO, Bailey KR, Oh JK, Rodeheffer RJ, et  al. New index of combined systolic and diastolic myocardial performance: a simple and reproducible measure of cardiac function—a study in normals and dilated cardiomyopathy. J Cardiol. 1995;26(6):357–66. 98. Tei C, Dujardin KS, Hodge DO, Kyle RA, Tajik AJ, Seward JB.  Doppler index combining systolic and diastolic myocardial performance: clinical value in cardiac amyloidosis. J Am Coll Cardiol. 1996;28(3):658–64. 99. Tei C, Nishimura RA, Seward JB, Tajik AJ. Noninvasive Doppler-­ derived myocardial performance index: correlation with simultaneous measurements of cardiac catheterization measurements. J Am Soc Echocardiogr. 1997;10(2):169–78. 100. Broberg CS, Pantely GA, Barber BJ, Mack GK, Lee K, Thigpen T, et al. Validation of the myocardial performance index by echocardiography in mice: a noninvasive measure of left ventricular function. J Am Soc Echocardiogr. 2003;16(8):814–23. 101. Eidem BW, Tei C, O'Leary PW, Cetta F, Seward JB. Nongeometric quantitative assessment of right and left ventricular function: myocardial performance index in normal children and patients with Ebstein anomaly. J Am Soc Echocardiogr. 1998;11(9):849–56. 102. Tei C, Dujardin KS, Hodge DO, Bailey KR, McGoon MD, Tajik AJ, et al. Doppler echocardiographic index for assessment

5  Functional Evaluation of the Heart of global right ventricular function. J Am Soc Echocardiogr. 1996;9(6):838–47. 103. Dujardin KS, Tei C, Yeo TC, Hodge DO, Rossi A, Seward JB. Prognostic value of a Doppler index combining systolic and diastolic performance in idiopathic-dilated cardiomyopathy. Am J Cardiol. 1998;82(9):1071–6. 104. Yeo TC, Dujardin KS, Tei C, Mahoney DW, McGoon MD, Seward JB. Value of a Doppler-derived index combining systolic and diastolic time intervals in predicting outcome in primary pulmonary hypertension. Am J Cardiol. 1998;81(9):1157–61. 105. Eidem BW, O’Leary PW, Tei C, Seward JB.  Usefulness of the myocardial performance index for assessing right ventricular function in congenital heart disease. Am J Cardiol. 2000;86(6): 654–8. 106. Williams RV, Ritter S, Tani LY, Pagoto LT, Minich LL. Quantitative assessment of ventricular function in children with single ventricles using the Doppler myocardial performance index. Am J Cardiol. 2000;86(10):1106–10. 107. Yasuoka K, Harada K, Toyono M, Tamura M, Yamamoto F. Tei index determined by tissue Doppler imaging in patients with pulmonary regurgitation after repair of tetralogy of Fallot. Pediatr Cardiol. 2004;25(2):131–6. 108. Shanewise JS, Cheung AT, Aronson S, Stewart WJ, Weiss RL, Mark JB, et  al. ASE/SCA guidelines for performing a comprehensive intraoperative multiplane transesophageal echocardiography examination: recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for Certification in Perioperative Transesophageal Echocardiography. J Am Soc Echocardiogr. 1999;12(10):884–900. 109. Hahn RT, Abraham T, Adams MS, Bruce CJ, Glas KE, Lang RM, et  al. Guidelines for performing a comprehensive transesophageal echocardiographic examination: recommendations from the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. J Am Soc Echocardiogr. 2013;26(9):921–64. 110. Cerqueira MD, Weissman NJ, Dilsizian V, Jacobs AK, Kaul S, Laskey WK, et  al. Standardized myocardial segmentation and nomenclature for tomographic imaging of the heart. A statement for healthcare professionals from the Cardiac Imaging Committee of the Council on Clinical Cardiology of the American Heart Association. Int J Cardiovasc Imaging. 2002;18(1):539–42. 111. Vegas A. Perioperative two-dimensional transesophageal echocardiography: a practical handbook. New York: Springer; 2012. 112. Lang RM, Badano LP, Mor-Avi V, Afilalo J, Armstrong A, Ernande L, et  al. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015;28(1):1–39. 113. Rouine-Rapp K, Rouillard KP, Miller-Hance W, Silverman NH, Collins KK, Cahalan MK, et al. Segmental wall-motion abnormalities after an arterial switch operation indicate ischemia. Anesth Analg. 2006;103(5):1139–46. 114. McMahon CJ, Nagueh SF, Pignatelli RH, Denfield SW, Dreyer WJ, Price JF, et  al. Characterization of left ventricular diastolic function by tissue Doppler imaging and clinical status in children with hypertrophic cardiomyopathy. Circulation. 2004;109(14):1756–62. 115. Nagueh SF, Middleton KJ, Kopelen HA, Zoghbi WA, Quiñones MA. Doppler tissue imaging: a noninvasive technique for evaluation of left ventricular relaxation and estimation of filling pressures. J Am Coll Cardiol. 1997;30(6):1527–33. 116. Nagueh SF, Mikati I, Kopelen HA, Middleton KJ, Quinones MA, Zoghbi WA. Doppler estimation of left ventricular filling pressure

163 in sinus tachycardia. A new application of tissue doppler imaging. Circulation. 1998;98(16):1644–50. 117. Sasaki N, Garcia M, Lytrivi I, Ko H, Nielsen J, Parness I, et al. Utility of Doppler tissue imaging-derived indices in identifying subclinical systolic ventricular dysfunction in children with restrictive cardiomyopathy. Pediatr Cardiol. 2011;32(5):646–51. 118. Goldberg DJ, Quartermain MD, Glatz AC, Hall EK, Davis E, Kren SA, et  al. Doppler tissue imaging in children following cardiac transplantation: a comparison to catheter derived hemodynamics. Pediatr Transplant. 2011;15(5):488–94. 119. Imai H, Kurokawa S, Taneoka M, Baba H. Tissue Doppler imaging is useful for predicting the need for inotropic support after cardiac surgery. J Anesth. 2011;25(6):805–11. 120. Kumar K, Nepomuceno RG, Chelvanathan A, Golian M, Bohonis S, Cleverley K, et  al. The role of tissue Doppler imaging in predicting left ventricular filling pressures in patients undergoing cardiac surgery: an intraoperative study. Echocardiography. 2013;30(3):271–8. 121. Gorcsan J 3rd, Tanaka H. Echocardiographic assessment of myocardial strain. J Am Coll Cardiol. 2011;58(14):1401–13. 122. Voigt JU, Cvijic M. 2- and 3-dimensional myocardial strain in cardiac health and disease. JACC Cardiovasc Imaging. 2019;12(9):1849–63. 123. Collier P, Phelan D, Klein A. A test in context: myocardial strain measured by speckle-tracking echocardiography. J Am Coll Cardiol. 2017;69(8):1043–56. 124. Abuelkasem E, Wang DW, Omer MA, Abdelmoneim SS, Howard-­ Quijano K, Rakesh H, et al. Perioperative clinical utility of myocardial deformation imaging: a narrative review. Br J Anaesth. 2019;123(4):408–20. 125. Benson MJ, Silverton N, Morrissey C, Zimmerman J.  Strain imaging: An everyday tool for the perioperative echocardiographer. J Cardiothorac Vasc Anesth. 2019; https://doi.org/10.1053/j. jvca.2019.11.035. 126. Friedberg MK, Mertens L.  Deformation imaging in selected congenital heart disease: is it evolving to clinical use? J Am Soc Echocardiogr. 2012;25(9):919–31. 127. Derumeaux G, Ovize M, Loufoua J, Pontier G, Andre-Fouet X, Cribier A. Assessment of nonuniformity of transmural myocardial velocities by color-coded tissue Doppler imaging: characterization of normal, ischemic, and stunned myocardium. Circulation. 2000;101(12):1390–5. 128. Weidemann F, Eyskens B, Jamal F, Mertens L, Kowalski M, D'Hooge J, et  al. Quantification of regional left and right ventricular radial and longitudinal function in healthy children using ultrasound-based strain rate and strain imaging. J Am Soc Echocardiogr. 2002;15(1):20–8. 129. Weidemann F, Eyskens B, Mertens L, Dommke C, Kowalski M, Simmons L, et al. Quantification of regional right and left ventricular function by ultrasonic strain rate and strain indexes after surgical repair of tetralogy of Fallot. Am J Cardiol. 2002;90(2):133–8. 130. Harada K, Toyono M, Yamamoto F. Assessment of right ventricular function during exercise with quantitative Doppler tissue imaging in children late after repair of tetralogy of Fallot. J Am Soc Echocardiogr. 2004;17(8):863–9. 131. Toyono M, Harada K, Tamura M, Yamamoto F, Takada G.  Myocardial acceleration during isovolumic contraction as a new index of right ventricular contractile function and its relation to pulmonary regurgitation in patients after repair of tetralogy of Fallot. J Am Soc Echocardiogr. 2004;17(4):332–7. 132. Scherptong RWC, Mollema SA, Blom NA, Kroft LJM, de Roos A, Vliegen HW, et al. Right ventricular peak systolic longitudinal strain is a sensitive marker for right ventricular deterioration in adult patients with tetralogy of Fallot. Int J Cardiovasc Imaging. 2009;25(7):669–76.

164 133. Friedberg MK, Mertens L.  Tissue velocities, strain, and strain rate for echocardiographic assessment of ventricular function in congenital heart disease. Eur J Echocardiogr. 2009;10(5): 585–93. 134. Forsey J, Friedberg MK, Mertens L. Speckle tracking echocardiography in pediatric and congenital heart disease. Echocardiography. 2013;30(4):447–59. 135. Nagueh SF, Appleton CP, Gillebert TC, Marino PN, Oh JK, Smiseth OA, et  al. Recommendations for the evaluation of left ventricular diastolic function by echocardiography. J Am Soc Echocardiogr. 2009;22(2):107–33. 136. Nagueh SF, Smiseth OA, Appleton CP, Byrd BF 3rd, Dokainish H, Edvardsen T, et  al. Recommendations for the evaluation of left ventricular diastolic function by echocardiography: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2016;29(4):277–314. 137. O’Leary PW, Durongpisitkul K, Cordes TM, Bailey KR, Hagler DJ, Tajik J, et  al. Diastolic ventricular function in children: a Doppler echocardiographic study establishing normal values and predictors of increased ventricular end-diastolic pressure. Mayo Clin Proc. 1998;73(7):616–28. 138. Dallaire F, Slorach C, Hui W, Sarkola T, Friedberg MK, Bradley TJ, et  al. Reference values for pulse wave Doppler and tissue Doppler imaging in pediatric echocardiography. Circ Cardiovasc Imaging. 2015;8(2):e002167. 139. Nicoara A, Whitener G, Swaminathan M. Perioperative diastolic dysfunction: a comprehensive approach to assessment by transesophageal echocardiography. Semin Cardiothorac Vasc Anesth. 2014;18(2):218–36. 140. Appleton CP, Hatle LK, Popp RL.  Relation of transmitral flow velocity patterns to left ventricular diastolic function: new insights from a combined hemodynamic and Doppler echocardiographic study. J Am Coll Cardiol. 1988;12(2):426–40. 141. Nishimura RA, Abel MD, Hatle LK, Tajik AJ. Assessment of diastolic function of the heart: background and current applications of Doppler echocardiography. Part II. Clinical studies. Mayo Clin Proc. 1989;64(2):181–204. 142. Bessen M, Gardin JM.  Evaluation of left ventricular diastolic function. Cardiol Clin. 1990;8(2):315–32. 143. Myreng Y, Smiseth OA.  Assessment of left ventricular relaxation by Doppler echocardiography. Comparison of isovolumic relaxation time and transmitral flow velocities with time constant of isovolumic relaxation. Circulation. 1990;81(1): 260–6. 144. Klein AL, Tajik AJ.  Doppler assessment of pulmonary venous flow in healthy subjects and in patients with heart disease. J Am Soc Echocardiogr. 1991;4(4):379–92. 145. Appleton CP, Galloway JM, Gonzalez MS, Gaballa M, Basnight MA.  Estimation of left ventricular filling pressures using two-­ dimensional and Doppler echocardiography in adult patients with cardiac disease. Additional value of analyzing left atrial size, left atrial ejection fraction and the difference in duration of pulmonary venous and mitral flow velocity at atrial contraction. J Am Coll Cardiol. 1993;22(7):1972–82. 146. Cohen GI, Pietrolungo JF, Thomas JD, Klein AL.  A practical guide to assessment of ventricular diastolic function using Doppler echocardiography. J Am Coll Cardiol. 1996;27(7):1753–60. 147. Hoit BD, Shao Y, Gabel M, Walsh RA. Influence of loading conditions and contractile state on pulmonary venous flow. Validation of Doppler velocimetry. Circulation. 1992;86(2):651–9. 148. Sohn DW, Chai IH, Lee DJ, Kim HC, Kim HS, Oh BH, et  al. Assessment of mitral annulus velocity by Doppler tissue imaging in the evaluation of left ventricular diastolic function. J Am Coll Cardiol. 1997;30(2):474–80. 149. Aranda JM Jr, Weston MW, Puleo JA, Fontanet HL.  Effect of loading conditions on myocardial relaxation velocities determined

B. W. Eidem by Doppler tissue imaging in heart transplant recipients. J Heart Lung Transplant. 1998;17(7):693–7. 150. Oki T, Fukuda K, Tabata T, Mishiro Y, Yamada H, Abe M, et al. Effect of an acute increase in afterload on left ventricular regional wall motion velocity in healthy subjects. J Am Soc Echocardiogr. 1999;12(6):476–83. 151. Muller S, Bartel T, Koopman J, Pandian NG, Erbel R, Pachinger O. Tissue Doppler analysis is hindered in abnormal wall motion and changes in afterload. Int J Cardiol. 2003;90(1):81–90. 152. Jacques DC, Pinsky MR, Severyn D, Gorcsan J 3rd. Influence of alterations in loading on mitral annular velocity by tissue Doppler echocardiography and its associated ability to predict filling pressures. Chest. 2004;126(6):1910–8. 153. Farias CA, Rodriguez L, Garcia MJ, Sun JP, Klein AL, Thomas JD. Assessment of diastolic function by tissue Doppler echocardiography: comparison with standard transmitral and pulmonary venous flow. J Am Soc Echocardiogr. 1999;12(8):609–17. 154. Garcia MJ, Thomas JD.  Tissue Doppler to assess diastolic left ventricular function. Echocardiography. 1999;16(5):501–8. 155. Rivas-Gotz C, Khoury DS, Manolios M, Rao L, Kopelen HA, Nagueh SF.  Time interval between onset of mitral inflow and onset of early diastolic velocity by tissue Doppler: a novel index of left ventricular relaxation: experimental studies and clinical application. J Am Coll Cardiol. 2003;42(8):1463–70. 156. Ruan Q, Rao L, Middleton KJ, Khoury DS, Nagueh SF. Assessment of left ventricular diastolic function by early diastolic mitral annulus peak acceleration rate: experimental studies and clinical application. J Appl Physiol. 1985;100(2):679–84. 157. Garcia MJ, Rodriguez L, Ares M, Griffin BP, Thomas JD, Klein AL.  Differentiation of constrictive pericarditis from restrictive cardiomyopathy: assessment of left ventricular diastolic velocities in longitudinal axis by Doppler tissue imaging. J Am Coll Cardiol. 1996;27(1):108–14. 158. Oki T, Tabata T, Yamada H, Abe M, Onose Y, Wakatsuki T, et  al. Right and left ventricular wall motion velocities as diagnostic indicators of constrictive pericarditis. Am J Cardiol. 1998;81(4):465–70. 159. Ha JW, Oh JK, Ommen SR, Ling LH, Tajik AJ. Diagnostic value of mitral annular velocity for constrictive pericarditis in the absence of respiratory variation in mitral inflow velocity. J Am Soc Echocardiogr. 2002;15(12):1468–71. 160. Ha JW, Ommen SR, Tajik AJ, Barnes ME, Ammash NM, Gertz MA, et al. Differentiation of constrictive pericarditis from restrictive cardiomyopathy using mitral annular velocity by tissue Doppler echocardiography. Am J Cardiol. 2004;94(3):316–9. 161. Garcia MJ. Constrictive pericarditis versus restrictive cardiomyopathy? J Am Coll Cardiol. 2016;67(17):2061–76. 162. Rychik J, Tian ZY. Quantitative assessment of myocardial tissue velocities in normal children with Doppler tissue imaging. Am J Cardiol. 1996;77(14):1254–7. 163. Harada K, Orino T, Yasuoka K, Tamura M, Takada G.  Tissue Doppler imaging of left and right ventricles in normal children. Tohoku J Exp Med. 2000;191:21–9. 164. Kapusta L, Thijssen JM, Cuypers MH, Peer PG, Daniels O. Assessment of myocardial velocities in healthy children using tissue Doppler imaging. Ultrasound Med Biol. 2000;26(2):229–37. 165. Mori K, Hayabuchi Y, Kuroda Y, Nii M, Manabe T.  Left ventricular wall motion velocities in healthy children measured by pulsed wave Doppler tissue echocardiography: normal values and relation to age and heart rate. J Am Soc Echocardiogr. 2000;13(11):1002–11. 166. Frommelt PC, Ballweg JA, Whitstone BN, Frommelt MA. Usefulness of Doppler tissue imaging analysis of tricuspid annular motion for determination of right ventricular function in normal infants and children. Am J Cardiol. 2002;89(5):610–3. 167. Swaminathan S, Ferrer PL, Wolff GS, Gomez-Marin O, Rusconi PG. Usefulness of tissue Doppler echocardiography for evaluat-

5  Functional Evaluation of the Heart ing ventricular function in children without heart disease. Am J Cardiol. 2003;91(5):570–4. 168. Eidem BW, McMahon CJ, Cohen RR, Wu J, Finkelshteyn I, Kovalchin JP, et  al. Impact of cardiac growth on Doppler tissue imaging velocities: a study in healthy children. J Am Soc Echocardiogr. 2004;17(3):212–21. 169. Savage A, Hlavacek A, Ringewald J, Shirali G.  Evaluation of the myocardial performance index and tissue Doppler imaging by comparison to near-simultaneous catheter measurements in pediatric cardiac transplant patients. J Heart Lung Transplant. 2010;29(8):853–8. 170. Nagueh SF, Kopelen HA, Quinones MA. Assessment of left ventricular filling pressures by Doppler in the presence of atrial fibrillation. Circulation. 1996;94(9):2138–45. 171. Sundereswaran L, Nagueh SF, Vardan S, Middleton KJ, Zoghbi WA, Quinones MA, et  al. Estimation of left and right ventricular filling pressures after heart transplantation by tissue Doppler imaging. Am J Cardiol. 1998;82(3):352–7. 172. Nagueh SF, Lakkis NM, Middleton KJ, Spencer WH 3rd, Zoghbi WA, Quinones MA.  Doppler estimation of left ventricular filling pressures in patients with hypertrophic cardiomyopathy. Circulation. 1999;99(2):254–61. 173. Border WL, Michelfelder EC, Glascock BJ, Witt SA, Spicer RL, Beekman RH 3rd, et al. Color M-mode and Doppler tissue evaluation of diastolic function in children: simultaneous correlation with invasive indices. J Am Soc Echocardiogr. 2003;16(9):988–94. 174. To AC, Flamm SD, Marwick TH, Klein AL.  Clinical utility of multimodality LA imaging: assessment of size, function, and structure. JACC Cardiovasc Imaging. 2011;4(7):788–98. 175. Sabatino J, Di Salvo G, Prota C, Bucciarelli V, Josen M, Paredes J, et al. Left atrial strain to identify diastolic dysfunction in children with cardiomyopathies. J Clin Med. 2019;8(8):1243. 176. Thomas L, Marwick TH, Popescu BA, Donal E, Badano LP. Left atrial structure and function, and left ventricular diastolic dysfunction: JACC state-of-the-art review. J Am Coll Cardiol. 2019;73(15):1961–77. 177. Di Salvo G, Pacileo G, Del Giudice EM, Natale F, Limongelli G, Verrengia M, et  al. Atrial myocardial deformation properties in obese nonhypertensive children. J Am Soc Echocardiogr. 2008;21(2):151–6. 178. Ghelani SJ, Brown DW, Kuebler JD, Perrin D, Shakti D, Williams DN, et  al. Left atrial volumes and strain in healthy children measured by three-dimensional echocardiography: normal values and maturational changes. J Am Soc Echocardiogr. 2018;31(2):187–93. 179. Kang SJ, Kwon YW, Hwang SJ, Kim HJ, Jin BK, Yon DK. Clinical utility of left atrial strain in children in the acute phase of Kawasaki disease. J Am Soc Echocardiogr. 2018;31(3):323–32. 180. Shakti D, Friedman KG, Harrild DM, Gauvreau K, Geva T, Colan SD, et  al. Left atrial size and function in patients with congenital aortic valve stenosis. Am J Cardiol. 2018; https://doi. org/10.1016/j.amjcard.2018.07.027. 181. Linden K, Goldschmidt F, Laser KT, Winkler C, Körperich H, Dalla-Pozza R, et  al. Left atrial volumes and phasic function in healthy children: reference values using real-time three-­ dimensional echocardiography. J Am Soc Echocardiogr. 2019; https://doi.org/10.1016/j.echo.2019.03.018. 182. Kwak J, Polito A, Majewski M, Adams W, Burcar K, Oftadeh M, et  al. Comparison of left atrial measurements using 2- and 3-dimensional transesophageal echocardiography. J Cardiothorac Vasc Anesth. 2019;33(6):1518–26. 183. Yock PG, Popp RL.  Noninvasive estimation of right ventricular systolic pressure by Doppler ultrasound in patients with tricuspid regurgitation. Circulation. 1984;70(4):657–62. 184. Zoghbi WA, Habib GB, Quinones MA.  Doppler assessment of right ventricular filling in a normal population. Comparison with left ventricular filling dynamics. Circulation. 1990;82(4):1316–24.

165 185. Moller JE, Poulsen SH, Egstrup K.  Effect of preload alternations on a new Doppler echocardiographic index of combined systolic and diastolic performance. J Am Soc Echocardiogr. 1999;12(12):1065–72. 186. Poelaert J, Ruggero A.  Myocardial performance index and tissue Doppler systolic wave velocity are preload dependent. Anesthesiology. 2005;103(1):210. 187. Anconina J, Danchin N, Selton-Suty C, Isaaz K, Juilliere Y, Buffet P, et  al. Noninvasive estimation of right ventricular dP/ dt in patients with tricuspid valve regurgitation. Am J Cardiol. 1993;71(16):1495–7. 188. Pai RG, Bansal RC, Shah PM. Determinants of the rate of right ventricular pressure rise by Doppler echocardiography: potential value in the assessment of right ventricular function. J Heart Valve Dis. 1994;3(2):179–84. 189. Michelfelder EC, Vermilion RP, Ludomirsky A, Beekman RH, Lloyd TR.  Comparison of simultaneous Doppler- and catheter-­ derived right ventricular dP/dt in hypoplastic left heart syndrome. Am J Cardiol. 1996;77(2):212–4. 190. Kanzaki H, Nakatani S, Kawada T, Yamagishi M, Sunagawa K, Miyatake K. Right ventricular dp/dt/pmax, not dp/dtmax, noninvasively derived from tricuspid regurgitation velocity is a useful index of right ventricular contractility. J Am Soc Echocardiogr. 2002;15(2):136–42. 191. Noori NM, Mehralizadeh S, Khaje A. Assessment of right ventricular function in children with congenital heart disease. Doppler tissue imaging. Saudi Med J. 2008;29(8):1168–72. 192. Helbing WA, Bosch HG, Maliepaard C, Zwinderman KH, Rebergen SA, Ottenkamp J, et al. On-line automated border detection for echocardiographic quantification of right ventricular size and function in children. Pediatr Cardiol. 1997;18(4):261–9. 193. Geva T, Powell AJ, Crawford EC, Chung T, Colan SD. Evaluation of regional differences in right ventricular systolic function by acoustic quantification echocardiography and cine magnetic resonance imaging. Circulation. 1998;98(4):339–45. 194. Jiang L, Siu SC, Handschumacher MD, Luis Guererro J, Vazquez de Prada JA, King ME, et al. Three-dimensional echocardiography. In vivo validation for right ventricular volume and function. Circulation. 1994;89(5):2342–50. 195. Fujimoto S, Mizuno R, Nakagawa Y, Dohi K, Nakano H. Estimation of the right ventricular volume and ejection fraction by transthoracic three-dimensional echocardiography. A validation study using magnetic resonance imaging. Int J Card Imaging. 1998;14(6):385–90. 196. Ota T, Fleishman CE, Strub M, Stetten G, Ohazama CJ, von Ramm OT, et al. Real-time, three-dimensional echocardiography: feasibility of dynamic right ventricular volume measurement with saline contrast. Am Heart J. 1999;137(5):958–66. 197. Nesser HJ, Tkalec W, Patel AR, Masani ND, Niel J, Markt B, et al. Quantitation of right ventricular volumes and ejection fraction by three-dimensional echocardiography in patients: comparison with magnetic resonance imaging and radionuclide ventriculography. Echocardiography. 2006;23(8):666–80. 198. Grison A, Maschietto N, Reffo E, Stellin G, Padalino M, Vida V, et  al. Three-dimensional echocardiographic evaluation of right ventricular volume and function in pediatric patients: validation of the technique. J Am Soc Echocardiogr. 2007;20(8): 921–9. 199. Khoo NS, Young A, Occleshaw C, Cowan B, Zeng IS, Gentles TL. Assessments of right ventricular volume and function using three-dimensional echocardiography in older children and adults with congenital heart disease: comparison with cardiac magnetic resonance imaging. J Am Soc Echocardiogr. 2009;22(11): 1279–88. 200. Grewal J, Majdalany D, Syed I, Pellikka P, Warnes CA.  Three-­ dimensional echocardiographic assessment of right ventricular volume and function in adult patients with congenital heart dis-

166 ease: comparison with magnetic resonance imaging. J Am Soc Echocardiogr. 2010;23(2):127–33. 201. Fusini L, Tamborini G, Gripari P, Maffessanti F, Mazzanti V, Muratori M, et al. Feasibility of intraoperative three-dimensional transesophageal echocardiography in the evaluation of right ventricular volumes and function in patients undergoing cardiac surgery. J Am Soc Echocardiogr. 2011;24(8):868–77. 202. van der Zwaan HB, Geleijnse ML, McGhie JS, Boersma E, Helbing WA, Meijboom FJ, et al. Right ventricular quantification in clinical practice: two-dimensional vs. three-dimensional echocardiography compared with cardiac magnetic resonance imaging. Eur J Echocardiogr. 2011;12(9):656–64. 203. Renella P, Marx GR, Zhou J, Gauvreau K, Geva T. Feasibility and reproducibility of three-dimensional echocardiographic assessment of right ventricular size and function in pediatric patients. J Am Soc Echocardiogr. 2014;27(8):903–10. 204. Nillesen MM, van Dijk AP, Duijnhouwer AL, Thijssen JM, de Korte CL. Automated assessment of right ventricular volumes and function using three-dimensional transesophageal echocardiography. Ultrasound Med Biol. 2016;42(2):596–606. 205. Laser KT, Karabiyik A, Korperich H, Horst JP, Barth P, Kececioglu D, et  al. Validation and reference values for three-dimensional echocardiographic right ventricular volumetry in children: a multicenter study. J Am Soc Echocardiogr. 2018;31(9):1050–63. 206. Heusch A, Rubo J, Krogmann ON, Bourgeois M.  Volumetric analysis of the right ventricle in children with congenital heart defects: comparison of biplane angiography and transthoracic 3-­ dimensional echocardiography. Cardiol Young. 1999;9(6):577–84. 207. van den Bosch AE, Robbers-Visser D, Krenning BJ, Voormolen MM, McGhie JS, Helbing WA, et  al. Real-time transthoracic three-dimensional echocardiographic assessment of left ventricular volume and ejection fraction in congenital heart disease. J Am Soc Echocardiogr. 2006;19(1):1–6. 208. van der Zwaan HB, Helbing WA, Boersma E, Geleijnse ML, McGhie JS, Soliman OII, et  al. Usefulness of real-time three-­ dimensional echocardiography to identify right ventricular dysfunction in patients with congenital heart disease. Am J Cardiol. 2010;106(6):843–50. 209. Okumura K, Slorach C, Mroczek D, Dragulescu A, Mertens L, Redington AN, et  al. Right ventricular diastolic performance in children with pulmonary arterial hypertension associated with congenital heart disease: correlation of echocardiographic parameters with invasive reference standards by high-fidelity micromanometer catheter. Circ Cardiovasc Imaging. 2014;7(3):491–501. 210. Selly JB, Iriart X, Roubertie F, Mauriat P, Marek J, Guilhon E, et al. Multivariable assessment of the right ventricle by echocardiography in patients with repaired tetralogy of Fallot undergoing pulmonary valve replacement: a comparative study with magnetic resonance imaging. Arch Cardiovasc Dis. 2015;108(1):5–15. 211. Jone PN, Patel SS, Cassidy C, Ivy DD. Three-dimensional echocardiography of right ventricular function correlates with severity of pediatric pulmonary hypertension. Congenit Heart Dis. 2016;11(6):562–9. 212. De Simone R, Wolf I, Mottl-Link S, Bottiger BW, Rauch H, Meinzer HP, et al. Intraoperative assessment of right ventricular volume and function. Eur J Cardiothorac Surg. 2005;27(6):988–93.

B. W. Eidem 213. Karhausen J, Dudaryk R, Phillips-Bute B, Rivera JD, de Lange F, Milano CA, et  al. Three-dimensional transesophageal echocardiography for perioperative right ventricular assessment. Ann Thorac Surg. 2012;94(2):468–74. 214. Bartels K, Karhausen J, Sullivan BL, Mackensen GB.  Update on perioperative right heart assessment using transesophageal echocardiography. Semin Cardiothorac Vasc Anesth. 2014;18(4):341–51. 215. Cronin B, O’Brien EO, Gu W, Banks D, Maus T. Intraoperative 3-dimensional echocardiography-derived right ventricular volumetric analysis in chronic thromboembolic pulmonary hypertension patients before and after pulmonary thromboendarterectomy. J Cardiothorac Vasc Anesth. 2019;33(6):1498–503. 216. Tamborini G, Brusoni D, Torres Molina JE, Galli CA, Maltagliati A, Muratori M, et  al. Feasibility of a new generation three-­ dimensional echocardiography for right ventricular volumetric and functional measurements. Am J Cardiol. 2008;102(4):499–505. 217. Tamborini G, Muratori M, Brusoni D, Celeste F, Maffessanti F, Caiani EG, et al. Is right ventricular systolic function reduced after cardiac surgery? A two- and three-dimensional echocardiographic study. Eur J Echocardiogr. 2009;10(5):630–4. 218. Vegas A, Meineri M. Core review: three-dimensional transesophageal echocardiography is a major advance for intraoperative clinical management of patients undergoing cardiac surgery: a core review. Anesth Analg. 2010;110(6):1548–73. 219. Cheung YF, Penny DJ, Redington AN.  Serial assessment of left ventricular diastolic function after Fontan procedure. Heart. 2000;83(4):420–4. 220. Mahle WT, Coon PD, Wernovsky G, Rychik J. Quantitative echocardiographic assessment of the performance of the functionally single right ventricle after the Fontan operation. Cardiol Young. 2001;11(4):399–406. 221. Earing MG, Cetta F, Driscoll DJ, Mair DD, Hodge DO, Dearani JA, et  al. Long-term results of the Fontan operation for double-­ inlet left ventricle. Am J Cardiol. 2005;96(2):291–8. 222. Frommelt PC, Snider AR, Meliones JN, Vermilion RP.  Doppler assessment of pulmonary artery flow patterns and ventricular function after the Fontan operation. Am J Cardiol. 1991;68(11):1211–5. 223. Penny DJ, Rigby ML, Redington AN. Abnormal patterns of intraventricular flow and diastolic filling after the Fontan operation: evidence for incoordinate ventricular wall motion. Br Heart J. 1991;66(5):375–8. 224. Olivier M, O'Leary PW, Pankratz VS, Lohse CM, Walsh BE, Tajik AJ, et  al. Serial Doppler assessment of diastolic function before and after the Fontan operation. J Am Soc Echocardiogr. 2003;16(11):1136–43. 225. Bassareo PP, Tumbarello R, Piras A, Mercuro G.  Evaluation of regional myocardial function by Doppler tissue imaging in univentricular heart after successful Fontan repair. Echocardiography. 2010;27(6):702–8. 226. Ikemba CM, Su JT, Stayer SA, Miller-Hance WC, Eidem BW, Bezold LI, et al. Myocardial performance index with sevoflurane-­ pancuronium versus fentanyl-midazolam-pancuronium in infants with a functional single ventricle. Anesthesiology. 2004;101(6):1298–305.

6

Systemic and Pulmonary Venous Anomalies Theresa Ann Tacy and Shiraz Arif Maskatia

Abbreviations 2D Two-dimensional Ao Aortic Asc Ascending ASD Atrial septal defect Atr Atrial BCPA Bidirectional cavopulmonary anastomosis CS Coronary sinus Desc Descending DTG Deep transgastric Hep Veins Hepatic veins IVC Inferior vena cava LA Left atrium LAA Left atrial appendage LAX Long axis Lf Left LIV Left innominate vein LLPV Left lower pulmonary vein LPA Left pulmonary artery LSVC Left superior vena cava LUPV Left upper pulmonary vein LV Left ventricle ME Midesophageal MRI Magnetic resonance imaging PA Pulmonary artery PAPVC Partial anomalous pulmonary venous connection Pulm Pulmonary RA Right atrium Electronic Supplementary Material The online version of this chapter (https://doi.org/10.1007/978-­3-­030-­57193-­1_6) contains supplementary material, which is available to authorized users. T. A. Tacy · S. A. Maskatia (*) Betty Irene Moore Children’s Heart Center, Lucile Packard Children’s Hospital, and Stanford University School of Medicine, Palo Alto, CA, USA e-mail: [email protected]; [email protected]

RAA Right atrial appendage RLPV Right lower pulmonary vein RPA Right pulmonary artery RSVC Right superior vena cava Rt Right RUPV Right upper pulmonary vein RV Right ventricular SAX Short axis Sept Septal SVC Superior vena cava TAPVC Total anomalous pulmonary venous connection TEE Transesophageal echocardiography TG Transgastric TTE Transthoracic echocardiography UE Upper esophageal Key Learning Objectives • Define standard transesophageal echocardiography (TEE) imaging planes used to visualize the anatomy of the large central systemic veins and the pulmonary veins • Examine Doppler flow patterns across the systemic and pulmonary veins and distinguish between normal and abnormal findings • Characterize the most common systemic and pulmonary venous anomalies by TEE • Understand key components of the preoperative and postoperative TEE assessment of systemic/pulmonary venous anomalies • Recognize the role of TEE in defining complications associated with these repairs

Introduction Anomalies of the systemic and pulmonary venous connections vary widely, both in their morphology and their clinical presentation [1, 2]. In the general population, the incidence

© Springer Nature Switzerland AG 2021 P. C. Wong, W. C. Miller-Hance (eds.), Transesophageal Echocardiography for Pediatric and Congenital Heart Disease, https://doi.org/10.1007/978-3-030-57193-1_6

167

168

of systemic venous anomalies is only 0.3–0.4%, yet among patients requiring surgery for congenital heart defects, these anomalies are more prevalent, occurring in 2.8–4.8% of operative cases [3]. In view of the important implications of these anomalies for surgical management, their definition is important before and immediately after surgical intervention. Transesophageal echocardiography (TEE) is well suited for evaluating both systemic and pulmonary venous structures because of the proximity of the transducer to the sites of venous return and the atria [4]. Although tomographic imaging modalities such as magnetic resonance imaging (MRI) and computed tomography angiography can provide superior definition of extracardiac vascular structures, echocardiography remains an important tool in the diagnosis and management of these anomalies [5]. Additionally, TEE is the imaging modality of choice in the operating room, and plays a valuable role in the evaluation of systemic and pulmonary venous anomalies. It can be especially useful in identifying previously undiagnosed vascular anomalies that may have clinical implications, and in detecting residual venous obstruction or related problems intraoperatively in order for the surgical intervention to be revised immediately, if necessary. Imaging normal systemic venous structures by TEE is relatively straightforward. However, systemic venous anatomy is highly variable and systemic venous anomalies can be missed if a complete evaluation of these structures is not performed routinely. Identifying an anomalous venous connection requires a heightened index of suspicion of its presence, instilled by either (1) knowledge of known or potential associations between a particular lesion and anomalous venous connections, or (2) associating the patient’s clinical scenario with possible anomalous venous connections. Transesophageal imaging of systemic and pulmonary venous anomalies presents a unique diagnostic challenge. This assessment requires departing from the familiarity of imaging from anterior windows via transthoracic echocardiography (TTE). Instead, when performing a TEE, one usually views cardiac structures through posterior esophageal and gastric  windows by looking anteriorly. To define the structures draining into the heart, one must image laterally and posteriorly from the esophagus to view the pulmonary veins, superiorly to image the superior vena cava (SVC) and innominate veins, and inferiorly to visualize the inferior vena cava (IVC) and hepatic veins (Hep veins). The ‘loss’ of cardiac structures within the image can be disorienting. This issue can be ameliorated by using easily found normal structures (e.g., the SVC) as “anchors” to understand the anatomic relationship of the structure one desires to interrogate—e.g., the right upper pulmonary vein (RUPV)—to the known structure (the SVC located rightward and superior), and then maneuvering the probe to image the structure of interest (by rotating rightward from the SVC in the sagittal plane). Making one’s way through the complexities of car-

T. A. Tacy and S. A. Maskatia

diac anatomy in space requires context. By thinking of the anatomy in relational terms, one can explore the extracardiac anatomy and ultimately perform a more comprehensive examination.

Systemic Veins General Considerations  ormal Systemic Venous Anatomy N The left innominate vein (LIV) is located anterior and superior to the ascending aorta (Asc Ao) and travels in a transverse (horizonal) plane. Its position is often helpful in locating the innominate artery because the vein courses immediately anterior to the origin of the innominate artery from the aorta. The SVC is a right-sided structure (referred to as right SVC or RSVC in some cases, particularly in the context of bilateral SVCs) and courses anterior to the right pulmonary artery (RPA) in a relatively straight, cephalad-to-caudal orientation. The SVC courses parallel to and rightward of the Asc Ao. The SVC enters the right atrium (RA) adjacent to the interatrial septum. The IVC also courses relatively straight, through the liver, in a caudal-to-cephalad path. The Hep veins course toward the IVC from different angles, which reflect their role in draining the respective lobes of the liver. Usually there are three major Hep veins—left, middle, and right—that drain respective portions of the liver.

 ransesophageal Examination of Normal T Systemic Veins Two-Dimensional Imaging Identifying the atrial appendages can assist in differentiating the atria. The RA is characterized by its broad-based, blunt-­ appearing right atrial appendage (RAA). This feature is best appreciated in the sagittal plane (~90°) in the midesophageal (ME) bicaval view (ME Bicaval), where the base of the RAA is seen anterior to the entrance of the SVC (Fig. 6.1 and Video 6.1). Within the RA, the Eustachian valve can be seen as a linear structure extending from the anterior border of the entrance of the IVC into the RA, and coursing parallel to the atrial septum. This structure at times can be mistaken for the atrial septum. The potential error is easily avoided simply by recalling that the IVC normally drains into the RA, because if the Eustachian valve were the atrial septum, then the IVC would drain into the left atrium (LA) instead. The narrow, finger-like left atrial appendage (LAA) that characterizes the LA can be seen at 0° with anteflexion or withdrawal of the probe from the ME four-chamber view (ME 4-Ch) and slight counterclockwise rotation of the probe shaft; alternatively, it can be displayed by forward-rotating the imaging plane to ~80°–100° to obtain the ME two-chamber view (ME 2-Ch; Fig. 6.2 and

6  Systemic and Pulmonary Venous Anomalies

169

Fig. 6.1  Image of the right atrial appendage (RAA) in a ME Bicaval view. The superior vena cava (SVC) is seen to the right of the image display as it enters into the right atrium (RA). The right pulmonary artery (RPA) is displayed in cross-section (short axis) as it courses posterior to the SVC. The broad-based RAA is seen anteriorly

Fig. 6.2  Image of the left atrial appendage (LAA) in a ME 2-Ch view. The left upper pulmonary vein (LPV) is visible, and directly anterior to its entrance into the left atrium (LA), the narrow-based LAA is seen. A mildly dilated coronary sinus (CS) is seen posteriorly along the atrioventricular groove. LV left ventricle

Video 6.2) [6]. The LAA can be further characterized from the ME LAA view by centering the LA in the image sector at the ME level, adjusting the depth to focus on the LA, and rotating the transducer angle forward to ~90°–110°. The variable anatomy of the LAA may require clockwise-counterclockwise rotation of the TEE probe shaft, adjustments in the transducer angle, and, frequently, multiple views. A normal RSVC can be imaged by starting in a transverse plane (~0°) at the ME 4-Ch view, then withdrawing the probe to the SVC-RA junction. The SVC will be bisected by the imaging plane in the ME Asc Ao short-axis view  (ME

Asc Ao SAX; transducer angle ~0°–30°). Once seen, if the transducer angle is then rotated forward to ~90°–110° and the probe withdrawn, the SVC can be imaged in its long axis in the ME Bicaval view. The SVC course anterior to the RPA will be obvious in this plane (Fig. 6.1 and Video 6.1). If the Asc Ao is seen, then clockwise rotation of the TEE probe will result in imaging of the SVC in the normal heart. The course of the IVC and Hep veins can be imaged starting from the ME Bicaval view with probe advancement past the level of the diaphragm into the transgastric (TG) level (Fig. 6.3 and Video 6.3). As the probe is advanced, the entrance of the IVC into the RA can be delineated, as can the drainage of the Hep veins into the IVC. One must remember to observe all the poles of the Hep veins, because a separate entrance from a posterior lobe can be easily missed. Normally, the IVC enters the RA very close to the midline, just adjacent to the atrial septum. The long axis of the IVC and its entrance to the RA can also be seen in the TG IVC/Hep veins view, with a transducer angle of ~80°–100°; however, the left-right orientation of the image can be lost in this view (Fig. 6.4 and Video 6.4). Keeping the same image position while adjusting the transducer angle to 0° produces a short-axis view of the IVC below the level of the heart. The TEE probe can be rotated in a clockwise-counterclockwise direction to determine the relation of the infradiaphragmatic vessels to one another. The probe can then be gradually withdrawn in a sweep-like fashion to visualize the venous (Eustachian) valve within the RA, the roof of the RA, and the connection of the RA to the SVC. An alternate view of the systemic veins as these enter the heart can be obtained as the probe is advanced from a TG

170

T. A. Tacy and S. A. Maskatia

location at 0° to a deep transgastric (DTG) level. Once an outflow tract is displayed, the transducer angle is rotated forward to ~80°–90° and the probe shaft is rotated clockwise to obtain the DTG atrial septal view (DTG Atr Sept). The assessment of the caval veins as each one joins the atria may require adjustment of the plane by rotating the transducer angle and/ or probe shaft. At times, it may be challenging to display both veins entering the heart in the same view. Starting with the DTG Atr Sept view but with further forward transducer angle

rotation to ~120°–140° can better show the entrance of the IVC into the RA. The LIV can be imaged throughout its length by starting from a ME 4-Ch view, then rotating the transducer shaft leftward beyond the cardiac mass, toward the patient’s spine, until the descending aorta (Desc Ao) is seen in its short axis (Desc Ao SAX view; transducer angle ~0°–10°). Keeping the descending aorta in the center of the image sector, the transducer angle is then  rotated forward to ~90°–100° to image the proximal Desc Ao in its long axis (Desc Ao LAX view) and the probe is maneuvered superiorly. With further probe withdrawal and slight anteflexion, once the transducer plane is rotated back to 0°–10°, the transverse arch can be imaged in the upper esophageal (UE) aortic arch long-axis view (UE Ao Arch LAX). If the probe shaft is then rotated from the  left to  the right, the innominate vein will appear anterior to the upper thoracic aorta and transverse arch as it courses in a horizontal plane [7]. Although obtaining these views may be feasible, the tracheal air column may preclude a complete examination of vascular structures at this level. The coronary sinus (CS) can be visualized from the ME 4-Ch view by retroflexing the probe, where it can be seen traversing the atrioventricular groove behind the LA before entering the RA (Fig. 6.5 and Video 6.5). To depict the relation between the CS and the LA), a sagittal ME view can be used.

Fig. 6.3  Transgastric view showing the hepatic veins (Hep Veins) entering the inferior vena cava (IVC) in a nearly coronal plane. Please note that in this example the image has been up/down inverted relative to the standard orientation for transgastric imaging. This cross-section allows for optimal spectral Doppler interrogation of hepatic venous flows. RA right atrium

 ystemic Venous Flow Doppler: Normal S and Abnormal Patterns The normal flow pattern in the SVC is characterized by a biphasic forward flow in systole (S wave) and early diastole (D wave), with forward flow being halted and briefly

Fig. 6.4  TG IVC/Hep veins view, obtained by advancing the imaging probe from the ME Bicaval view further into the lower esophagus/gastric region just beyond the level of the diaphragm. A hepatic vein (HV) is seen joining the inferior vena cava (IVC) anteriorly and superiorly

6  Systemic and Pulmonary Venous Anomalies

171

Fig. 6.5  Image obtained after advancing and retroflexing the imaging probe from the ME 4-Ch view showing the coronary sinus (CS) and its relation to the left atrium (LA). Note the normal opening of the CS into the right atrium (RA)

reversed by atrial contraction (A wave) [8, 9]. In children, the systolic flow is greater than the diastolic flow as assessed by either flow velocity or velocity time integral. In evaluating systemic venous obstruction, assessing the flow pattern is often more important than obtaining the gradient by spectral Doppler. Stenosis in a venous structure manifests primarily as loss of the phasic flow pattern. The absolute gradient may vary with the preload status at the time of the examination, as well as the capacitance of the venous bed proximal to the obstruction. Systemic venous ­obstruction is most often caused by extrinsic compression from a mass, but can also represent a postsurgical surgical complication, especially after baffling of an anomalous RUPV to the SVC-RA junction (Fig.  6.6 and Video 6.6). Other causes of SVC obstruction include narrowing from multiple pacing leads in the patient with a transvenous pacing system, as well as obstruction from an indwelling catheter or thrombus, which is always a consideration in the patient with a chronic illness requiring long-standing venous access. Imaging in the sagittal (longitudinal) plane (~90°) by interrogating the SVC in the ME Bicaval view is most helpful for viewing the vessel and assessing for potential narrowing, whereas supplemental imaging in the transverse plane (~0°) at multiple levels may be critical to determining the cause of the obstruction, if unknown. TEE may not allow imaging of the entire SVC, particularly the upper portions of the vessel. Nonetheless, DTG views, particularly the DTG Atr Sept view when available, can provide excellent angles for color flow assess-

ment and spectral Doppler evaluation of SVC inflow. Due to limitations of spectral Doppler in estimating gradients of continuous flow structures, simultaneous invasive pressure measurements should be obtained whenever possible to confirm a suspicion of venous obstruction. The normal flow pattern in the Hep veins is toward the RA in systole and diastole, with a mildly dominant systolic flow signal, yet the forward flow waves are interrupted by a reverse flow signal [10]. Flow also reverses during atrial systole. Thus, the normal hepatic venous signal has a to-and-­fro appearance. Doppler evaluation of the Hep veins can be performed from the TG IVC/Hep veins view and equivalent views. A study assessing  systemic venous flow patterns in children by Doppler echocardiography noted a significant decrease in peak velocities in all veins during expiration [11]. This decrease was found to be more prominent in the Hep veins than in the SVC.

Systemic Venous Anomalies  ersistent Left Superior Vena Cava Draining P into the Coronary Sinus General Considerations More than 90% of cases of persistent left superior vena cava (LSVC) drain into the RA via a CS [12]. This condition is common, occurring in approximately 0.5% of the

172

a

T. A. Tacy and S. A. Maskatia

b

PA

SVC

RA

c

Fig. 6.6  Panel a, ME Bicaval view after repair of sinus venosus atrial septal defect, showing color flow disturbance near the entrance of the superior vena cava (SVC) into the right atrium (RA). Panel b, diagrammatic representation of findings. Panel c, significant obstruction across

the SVC noted by spectral Doppler, with a mean pressure gradient of ~9 mmHg. The repair was revised, which resolved the venous obstruction. PA, right pulmonary artery

general population [13–15] and in 3–10% of patients with congenital heart defects [16]. Although generally associated with bilateral SVCs, several reports cite total absence of the RSVC in 17% of patients with a persistent LSVC [16, 17]. This appears to be substantially less common in our clinical experience. Identifying an LSVC is important in the patient undergoing surgery because it may affect the choice of venous cannulation strategy, given that in the absence of a LIV or bridging vein, both venous structures (right and left SVCs) may need to be drained into the bypass circuit. In addition, an LSVC draining into the CS can complicate atrial baffle procedures because the CS is usually incorporated into the pulmonary venous atrium, which would not be wise given the increased volume of desaturated blood the CS would carry in this setting [18].

The presence of bilateral SVCs has more significance in the execution of a bidirectional cavopulmonary anastomosis (BCPA) or Glenn connection. It has been reported that bilateral BCPA poses greater risk to the patient than a single BCPA [19]. Central pulmonary artery (PA) hypoplasia may develop in this population after a bilateral BCPA, which may be ameliorated by preserving low-grade antegrade pulmonary blood flow [20]. Bilateral SVCs can also affect heart transplantation, in that more LIV tissue  might need to be harvested with the donor heart, especially if the intended recipient has undergone a bilateral BCPA. In these patients, both the right and left SVC can then be anastomosed to the donor LIV without need for additional reconstruction [18]. Other clinically important implications of the presence of an LSVC may relate to the administration of retrograde

6  Systemic and Pulmonary Venous Anomalies

cardioplegia in adult patients, and to the placement of catheters such as central venous lines and PA catheters, as these may take unusual courses [21].

Transesophageal Echocardiography A dilated CS can be identified as an echo-free structure between the posterior mitral leaflet and the LA. To image the CS in its long axis, the examination is initiated in the usual ME 4-Ch view and the probe is slightly advanced within the esophagus (see Fig. 6.5). A short-axis image of the CS can be obtained in the ME 2-Ch view at a transducer angle of ~80°–100° (Fig. 6.7 and Video 6.7) and at times may be also seen in the ME long-axis view (ME LAX; transducer angle ~120°–140°). A dilated CS should prompt a search for a persistent LSVC. If none is found, other potential causes of a dilated CS should be investigated, such as anomalous pulmonary or hepatic venous drainage to the CS, partial unroofing of the CS septum, CS orifice atresia or stenosis, elevated RA pressure, tricuspid regurgitation directed into the CS, or coronary artery fistula to the CS. The LSVC courses anterior to the left pulmonary artery (LPA), between the left pulmonary veins and the LAA. This vessel can be visualized longitudinally from the ME to UE windows at a transducer angle of ~60°–80°, descending to the left of the aortic arch and anterior to the LPA towards the atrioventricular groove, where it continues into the CS (Fig. 6.8 and Video 6.8). Pulsed and color Doppler confirm the direction of LSVC flow as being toward the heart. Certain vessels resemble an LSVC and have the same embryologic origin from the left cardinal venous system but have venous flow away from the heart; these include Fig. 6.7  ME 2-Ch view displaying a dilated coronary sinus (CS) in a patient undergoing mitral valve surgery. LA left atrium; LV left ventricle

173

a left vertical vein in patients with anomalous pulmonary venous drainage into the LIV, and a levoatrial cardinal vein in those with mitral atresia and an intact atrial septum [22, 23]. If the LSVC cannot be adequately imaged, injecting agitated saline into a left arm vein or left jugular vein, which results in opacification of the CS, will confirm the diagnosis (refer to Chap. 7 for Fig.  7.20 and Video 7.20) [24, 25]. The ME Bicaval view is useful for determining whether an RSVC is present. When bilateral superior cavae are present, the LIV is usually either hypoplastic or absent [26, 27]. Patients lacking an RSVC usually have an LSVC draining into a dilated CS or directly into the LA [28–30]. In these cases, the LIV is well developed (refer to Chap. 4, Figs. 4.12 and 4.51, Videos 4.3 and 4.41). A dilated CS associated with a persistent LSVC has led to diagnostic errors; in some cases, the opening of the CS in the RA has been misidentified as an atrial septal defect (ASD). This error can be avoided by comprehensive anterior and posterior scanning from the ME 4-Ch view as the probe is anteflexed and retroflexed to display the anatomical details, color Doppler interrogation is applied, and structures of interest are examined in multiple planes.

 nomalous Subaortic Position A of the Innominate Vein (Retroaortic Innominate Vein) General Considerations In approximately 1% of patients with congenital heart disease (CHD), the LIV is retroaortic, taking an anomalous

174

T. A. Tacy and S. A. Maskatia

Fig. 6.8  Image of a dilated coronary sinus (CS) in its longitudinal plane as it receives a left superior vena cava (LSVC) as shown by color flow mapping. This view can obtained after initially displaying the CS in short axis in the ME 4-Ch view and rotating the transducer plane forward to ~60°–80°. LA left atrium; LV left ventricle

course underneath the aortic arch [31–33]. A retroaortic LIV is most often seen in patients with tetralogy of Fallot or ventricular septal defect with pulmonary atresia, in particular, in those with an associated right aortic arch [32, 34].

Transesophageal Echocardiography Although a retroaortic LIV by itself may not have clinical significance, the presence of this anomaly can have implications regarding echocardiographic imaging, as follows: (1) the retroaortic segment has the potential to be misinterpreted as the PA in patients with hypoplastic or atretic central PAs [32], (2) the descending portion of the vessel can be mistaken for an LSVC, or (3) the vessel can be erroneously identified as the ascending vertical vein of an anomalous pulmonary venous connection [34]. The anomalous subaortic position of the LIV can also influence venous cannulation during cardiac surgery and exposure during certain surgical procedures. Because the transesophageal windows may not allow a comprehensive examination of the aortic arch and neighboring structures, this anatomic variant cannot always be easily assessed by TEE.

rarely occurs in isolation [36]. More commonly, this defect is associated with significant intracardiac anomalies such as an ASD, common atrium, atrioventricular septal defect [16, 37–39], anomalous pulmonary venous return, coarctation of the aorta, tetralogy of Fallot, patent ductus arteriosus, transposition of the great arteries, and tricuspid atresia [38, 40].

Transesophageal Echocardiography The normal-sized CS is not easily seen on two-dimensional (2D) imaging. As a result, a persistent LSVC can be missed unless the LSVC is visualized directly or other subtle clues are detected, such as a small or absent LIV and/or RSVC, that prompt the search for an LSVC.  Alternatively, if an LSVC has been identified (either by TEE or by the surgeon) but the CS is not dilated, one must have a strong suspicion that the LSVC drains directly into the LA (refer to Chap. 12, Fig. 12.12 and Video 12.9). Injecting agitated saline or albumin contrast agent into a peripheral vein in a left arm or left head/neck vein will result in the appearance of “bubbles” in the LA, which is diagnostic in most cases.

 ersistent Left Superior Vena Cava Draining P into the Left Atrium

 ersistent Left Superior Vena Cava Draining P into a Coronary Sinus with a Coronary Sinus–Left Atrial Fenestration

General Considerations In approximately 8% of cases of persistent LSVC, there is direct drainage of the LSVC into the roof of the LA. Although this pattern can occur in right isomerism—a condition in which no CS is present [35]—it is not diagnostic of this entity. Direct communication of the LSVC to the LA

General Considerations A persistent LSVC draining into a fenestrated CS is similar to drainage of an LSVC into the LA, except that in this anomaly, a defect (i.e., a fenestration) is present between the CS and the LA. This defect is also referred to as an unroofed CS. The CS orifice opens into the RA in its usual position.

6  Systemic and Pulmonary Venous Anomalies

This condition can occur in isolation or with associated cardiac malformations [41]. A defect in the CS septum should be identified preoperatively as failure to address this ­anomaly during congenital heart surgery in cases where shunting is in the physiologic right-to-left direction can result in postoperative cyanosis. However if this defect is not too large, it can actually act as primarily a left-to-right shunt with LA blood draining into the CS. When there is atresia of one atrioventricular valve, the communication may represent the only egress of blood from the RA or LA in the absence of other communications at the atrial level [42, 43].

Transesophageal Echocardiography In the ME 4-Ch view, a dilated CS may be the first clue that an abnormality is present. The CS ostium can be dilated and may be confused with a primum ASD; the mouth of the CS can be distinguished from a primum ASD on the basis of a normal-appearing mitral valve and the CS orifice’s location posterior to the mitral valve annulus. The dilated mouth of the CS becomes more visible when the probe is advanced from the usual mitral valve–atrial septal junction to a more posterior view that displays the entire CS. In the ME 2-Ch view, the dilated CS is seen, as is the septum separating the CS from the LA. A defect in this septum can be clearly visualized by using this imaging plane (Fig. 6.9 and Video 6.9).

175

Contrast echocardiography is helpful, because contrast agent injected into a left arm/left neck vein will sequentially opacify the LSVC, CS, LA (Fig. 6.10), and finally the RA via the CS orifice [41]. This sequence can vary because it depends on regional pressure gradients. For example, if the shunt direction is predominantly left-to-right (that is, from the LA to the CS via the defect, to the RA), contrast agent injected into the left arm will stream predominantly into the RA, with negative contrast seen from the LA into the CS.

 ight Superior Vena Cava Connection R to the Left Atrium General Considerations Drainage of an RSVC predominately or entirely into the LA is a rare cardiac anomaly, particularly in the absence of associated cardiac malformations [44–48]. Most literature on the subject consists of case reports [49–53]. In two thirds of these cases, patients presented with cyanosis or evidence of chronic hypoxemia and no patient who presented with cyanosis had a LSVC. The second most common finding leading to the diagnosis of a RSVC to the LA is a brain abscess. Anomalous connection of the RUPV to the RSVC is often associated with RSVC-to-LA drainage.

Fig. 6.9  Panel a,  ME 2-Ch view of a dilated coronary sinus (CS; asterisk) separated from the left atrium (LA) by the normal CS septum. Panel b, equivalent view showing absence of septum in a CS septal defect. LV left ventricle

176

T. A. Tacy and S. A. Maskatia

Fig. 6.10  Image obtained in the same TEE plane shown in Fig. 6.9 (ME 2-Ch view) while agitated saline contrast was injected into a vein in the left arm. Dense opacification of contrast is seen in the coronary sinus (CS) spilling into left atrium (LA) consistent with a CS septal defect. The contrast was then washed back into the CS and the right atrium, so that overall scant contrast was visible in the left ventricle (LV) as shown

Transesophageal Echocardiography In this anomaly, the course and location of the RSVC is relatively normal until its entrance into the heart. Thus, imaging along the long axis of the SVC in the ME Bicaval view will often show the course of the RSVC, including its entrance into the LA. The prominent right sinoatrial fold can often be seen in this view (Fig. 6.11 and Video 6.10).

I nterrupted Inferior Vena Cava with Azygos Continuation General Considerations Interrupted IVC due to absence of its hepatic segment is a rare finding, occurring in only 0.6% of patients with congenital heart defects [54]. In this entity, the portion of the IVC above the renal veins and below the Hep veins is absent. The Hep veins drain directly into the RA, whereas the infrahepatic portion of the IVC as well as other systemic venous drainage below the diaphragm connects to the azygos vein (or hemiazygos vein in some cases), which drains the venous blood into the right SVC for azygos vein or LSVC for hemiazygos vein, depending upon which is present. Whereas distal absence of the IVC is only rarely found as an isolated lesion, it is common in patients with heterotaxy syndrome and is nearly a pathognomonic finding in left isomerism [55]. Awareness of the caval-azygos abnormality is important: Accidental ligation of the azygos vein has been reported to be fatal, and venous cardiac catheterization can be challeng-

ing in a patient with this condition [56]. Interruption of the IVC has technical implications for venous cannulation at the time of cardiac surgery: the snare around the SVC cannula should be distal to the azygos or hemiazygos flow; if not, the operative field will be flooded with blood from the IVC [57]. In addition, cannulating the Hep veins as they enter the heart may be necessary. Identifying this abnormality of venous anatomy is important in patients with single  ventricle physiology who are undergoing staged surgical palliation. The Kawashima operation, in which the flow from the SVC, also receiving the azygos/hemiazygos continuation, is routed to the pulmonary arteries via a BCPA, results in diversion of 75% of total systemic venous return to the pulmonary arterial tree. The pulmonary vascular resistance must be able to accept this volume load at the time of surgery, and for this reason the cavopulmonary connection may be delayed in the patient with an interrupted IVC [18]. Excluding hepatic venous return from the pulmonary blood flow can lead to development of diffuse pulmonary arteriovenous malformations. Subsequently incorporating Hep veins into the pulmonary blood flow via an extracardiac conduit or lateral tunnel (Fontan completion) has resulted in resolution of such malformations [58].

Transesophageal Echocardiography Transesophageal imaging of this entity must be directed. When an attempt to view the IVC in its long axis as it enters the RA (Fig. 6.4, Video 6.4) is not successful using the ­TG/ IVC Hep veins view, a search for the azygos vein should ensue

6  Systemic and Pulmonary Venous Anomalies

a

177

c

LA

PA

RA

SVC

b

Fig. 6.11  ME Bicaval view showing commitment of a right superior vena cava (SVC) to the left atrium (LA): Panel a, 2D image; Panel b, color Doppler showing flow from the SVC entering both the LA (larger

red signal) and the right atrium (RA) (smaller aliased  blue signal); Panel c, diagrammatic representation of the anatomy. The right pulmonary artery (PA) is depicted posterior to the SVC

(Fig. 6.12 and Video 6.11). The azygos continuation can be visualized in the retrocardiac position thusly: One begins by searching in the transverse plane (~0°) for a venous structure traveling in a paravertebral gutter. Alternately, a search using the sagittal plane (~90°) in the posterior thorax (i.e., looking behind the heart, close to the spine) may identify a vascular structure coursing with cranially directed venous flow suggestive of the presence of an azygos vein (Fig. 6.13 and Video 6.12). Ideally, the entrance of the azygos vein to the SVC should be visible, and one might expect that the plane of imaging would be at ~90° (ME Bicaval view). However, because of the orientation of the esophagus (parallel and to the left of the azygos course) and the close proximity of the right mainstem bronchus, imaging this structure can be challenging. Figure  6.14 and Video 6.13 show the azygos vein as it travels toward the SVC. At a transducer angle of ~90°, the distal azygos vein can be imaged in its short axis coursing over the RPA.  This relationship between azygos vein

and RPA also can also be appreciated at the level of the ME Asc Ao SAX view, with the transducer angle at ~0°. As the imaging  probe is  withdrawn from the ME 4-Ch view and turned clockwise the RPA is first visualized, then the probe is slightly anteflexed to display venous flow directed away from the transducer (i.e., anteriorly toward its entrance into the SVC).

Left-Sided Inferior Vena Cava General Considerations A left-sided IVC is an exceedingly rare anatomic variant with a prevalence of approximately 0.2–0.5% by best available estimates [59]. The recognition of cases in which the IVC drains into the systemic circulation (typically directly into the LA) is important, as it leads to a low arterial ­systemic oxygen saturation and affected patients are at high risk for

178

T. A. Tacy and S. A. Maskatia

Fig. 6.12  Panel a, TG IVC/Hep veins view of the normal anatomy showing a hepatic vein (HV) at it joins the inferior vena cava (IVC) superiorly. Panel b, in contrast, in the patient with an interrupted IVC, only hepatic veins (HVs) are seen in the equivalent view

Fig. 6.13  Panel a, two vascular structures are seen in this image coursing adjacent to each other with the probe in a low esophageal position and rotated posteriorly; the transducer is oriented in a sagittal plane. Panel b, the pulsed Doppler sample volume has been moved from the descending aorta, which has pulsatile arterial flow directed caudally, to the azygos vein, which has venous flow coursing cranially

6  Systemic and Pulmonary Venous Anomalies

a

179

b

rpa az

Fig. 6.14  Panel a, view of the azygos (az) vein (blue color flow) as it travels toward the superior vena cava. At a transducer angle of 90°, the distal azygos vein can be seen coursing over the right pulmonary artery (rpa), which is shown in its short axis. Note that entry of the az vein into

systemic embolic events. At the level of approximately T12, a left-sided IVC not draining into the LA may do one of the following: cross the aorta anteriorly to assume its normal, right-sided course above the renal vessels (most common course) [60], drain into a hemiazygos vessel [61], or split into two vessels: one that communicates with the distal right IVC, and one that is a hemiazygos continuation to a leftsided SVC [61, 62].

Transesophageal Echocardiography Initial concern for this anomaly arises usually by TTE.  Confirmation may be by any number of additional imaging modalities, including CT angiogram, invasive angiography, MRI, or TEE. The role of TEE is of utmost importance after surgical correction to ensure that no residual right-to-left shunt is present. This is where it is important to perform a careful sweep/withdrawal from the TG to the ME window with a transducer angle of ~0°, so one can observe the drainage of the IVC. This may also be optimally accomplished with an agitated saline contrast injection into the lower extremity.

Pulmonary Veins General Considerations  ormal Pulmonary Venous Anatomy N About 75–80% of individuals have four pulmonary veins with separate ostia into the LA; however, accessory veins can be present [63]. When there are four veins, the left pulmonary veins are located more superiorly than the right pulmonary veins. On each side, the upper (superior) veins

the superior vena cava is not shown. This is a modified view obtained at the level of the upper esophagus. Panel b, diagrammatic representation of the same view

LEFT

RIGHT

0°

180°

40-60°

110-130°

Fig. 6.15  Diagram displaying the orientation of the pulmonary veins and respective imaging planes. The center image shows a person, facing the reader. A line representing the long axis of the left ventricle through the base-apex axis is drawn (plane ~120°). When the person is viewed from the left (left image), the anterior position of the left upper pulmonary vein compared to the left lower vein is observed, as is the alignment of the ~120° plane of imaging with both orifices. When the person is viewed from the right (right image), the anterior position of the right upper pulmonary vein compared to the right lower vein is observed, as is the alignment of the ~60° plane of imaging with both orifices

join the LA in a more anterior position than the lower (inferior) pulmonary veins do (Fig. 6.15). The right middle and upper lobe veins join to form the RUPV. The RUPV passes

180

immediately behind the RSVC and inferior to the RPA. The left upper pulmonary vein (LUPV) receives blood draining from the left upper lobe. The LUPV connects to the LA just superior to the mouth of the LAA. The right and left lower pulmonary veins receive blood from the right and left lower lobes, respectively. A common vein—which occurs when upper and lower veins join proximal to the LA, resulting in a single orifice to the LA—is more frequently found on the left side [64].

T. A. Tacy and S. A. Maskatia

sided veins is to again start at the ME 4-Ch view and rotate the transducer plane forward to ~90°–110° to obtain the ME LAA view. Further counterclockwise probe rotation allows the ME left pulmonary veins view  (ME Lt Pulm veins) to be displayed, where both the LUPV and LLPV can be seen. In the transverse plane (~0°), the right pulmonary veins can be viewed, although these take slightly different angles as they join the LA. Imaging these structures to obtain the ME right pulmonary veins (ME Rt Pulm veins) view requires first centering the RA in the image sector at a transducer angle of 0° and then rotating the probe shaft rightward. As Transesophageal Imaging of Normal the probe is slightly advanced, the RUPV can be seen enterPulmonary Veins ing the LA from the right, coursing in an orientation that is relatively parallel to the angle of insonation (vertical path on Two-Dimensional Imaging the display) (Fig. 6.17 and Video 6.15). The transducer can Several TEE views can be used to evaluate the pulmonary be advanced slightly farther to image the right lower pulmoveins  (also refer to Chap. 4). Imaging usually begins with nary vein (RLPV), which courses in a more perpendicular the transducer positioned behind the LA, at ~0°. From the orientation relative to the imaging beam, meaning a more ME 4-Ch view, one approach is to rotate the probe shaft horizontal trajectory in the image display. From this view, leftward (counterclockwise) to identify the left pulmonary the angle of Doppler interrogation of the right pulmonary veins, which usually pass between the LAA and Desc Ao veins may be suboptimal at times, although it may be more (Fig.  6.16 and Video 6.14). The LUPV enters the LA just favorable for the RUPV than for the RLPV. lateral to the LAA coursing in a vertical trajectory. The left Another, potentially easier approach is to image the pullower pulmonary vein (LLPV) is then identified by turning monary veins on each side, in their long axis, as they reach slightly farther to the left and advancing the probe 1 to 2 cm toward the LA [7]. In doing so, it is helpful to recall that into the esophagus. The LLPV enters the LA just below on each side, the upper veins attach to the LA more anterithe LUPV. Because the LLPV courses in a more lateral-to-­ orly than the lower veins. To view the left pulmonary veins medial direction  or horizontal trajectory, it is less suitable using a multiplane transducer, the angle should be adjusted than the LUPV for Doppler quantification of pulmonary to ~90°–110° to obtain the ME Lt Pulm veins view. One can venous blood flow [65]. Another option to image the left-­ start from the ME LAX view and, while rotating leftward,

Fig. 6.16  Image obtained at a transducer angle of 0°. The probe has been withdrawn from the ME 4-Ch view and rotated leftward (counterclockwise) to visualize—from posterior to anterior—the descending aorta (DAO), left upper pulmonary vein (LPV), and left atrial appendage (LAA)

6  Systemic and Pulmonary Venous Anomalies

181

Fig. 6.17  ME Rt Pulm veins view obtained after the TEE probe was rotated rightward from the ME 4-Ch view to visualize the entrance of the right upper pulmonary vein (RUPV) into the left atrium (LA). RA right atrium

Fig. 6.18  ME Lt Pulm veins view obtained as the probe shaft is turned leftward from the ME LAX view (transducer angle of 125°) to visualize the left-sided pulmonary veins. LLPV left lower pulmonary vein; LUPV left upper pulmonary vein

withdraw the probe slightly and use color Doppler to assist in locating the pulmonary veins by detecting the flow where they enter the LA. If the Desc Ao is encountered, then the transducer has been rotated too far leftward (imaging more posteriorly than necessary) and it must be returned slightly anterior by rotating the shaft clockwise. Often, one or the other left pulmonary veins can be visualized first, and the transducer angle can be adjusted ±20° to 30° until both veins can be seen lengthwise as they approach the LA in an inverted ‘V’-like orientation (Fig. 6.18 and Video 6.16). In this view, the LUPV is displayed to the right of the screen

and the LLPV to the left. On occasion, secondary tributaries are also seen, as this approach seems to image the pulmonary veins along a greater length than other views allow. For the right pulmonary veins, a similar imaging approach can be used, although at an different angle to that previously described to obtain a view of the left pulmonary veins (almost perpendicular to it). One can start at either, the ME aortic valve short-axis view (ME AoV SAX; transducer angle ~25°–45°) or the ME right ventricular (RV) inflow-outflow view (ME RV in-out; transducer angle ~50°–70°, and rotate the probe shaft rightward (clockwise) to just past the level of the SVC. Color Doppler may aid in initially identifying and subsequently refining the imaging angle that will provide optimal views of both right pulmonary veins simultaneously (Fig. 6.19 and Video 6.17). In this view, the RUPV is seen to the right and the RLPV to the left of the image display. A helpful method of remembering which TEE transducer angle to use when imaging the right versus the left pulmonary veins is to recall that a ME view at a transducer angle of ~120° provides imaging of the inflow and outflow of the left ventricle (LV), so it also displays the left pulmonary veins when the plane is directed leftward and posteriorly by rotating the probe shaft to the left. Similarly, a ME view anywhere between a transducer angle of ~30° and 50° provides imaging of the inflow and outflow of the RV and also displays the right pulmonary veins when the plane is directed rightward and posteriorly by rotating the probe shaft to the right. These maneuvers allow for both pulmonary veins, either on the left or on the right to be seen in a single view

182

T. A. Tacy and S. A. Maskatia

Fig. 6.19  View of the right pulmonary veins from a midesophageal position with color flow mapping as they enter the left atrium. This view is obtained with rightward rotation of the probe after the ME RV In-Out view has been obtained and the transducer angle adjusted to ~30°–50°. RLPV right lower pulmonary vein; RMPV right middle pulmonary vein; RUPV right upper pulmonary vein

respectively. The TEE views described above have been integrated into the recently published TEE Guidelines in Children and All Patients with Congenital Heart Disease [66]. The reader is referred to this document and to Chap. 4 for additional details on the TEE assessment of the pulmonary veins.

 ulmonary Venous Flow Doppler: Normal P and Abnormal Patterns The normal pulmonary venous Doppler signal in adults has been well described. The standard of imaging is to use pulsed-wave Doppler and to place the sample volume within the pulmonary vein (~1 to 2 cm from its orifice). The normal pulmonary venous pattern in animal models and humans without cardiovascular disease is characterized by a triphasic forward flow pattern, with one brief period of flow reversal. Brief and low-velocity reverse pulmonary vein flow can occur during LA contraction (A wave). Afterward, there is atrial relaxation in early systole, so the LA pressure is lower than the pulmonary venous pressure; thus, pulmonary vein forward flow occurs in early systole (S1), followed by late systolic forward flow, which is thought to reflect the forward flow through the pulmonary bed as a result of RV contraction (S2). During ventricular relaxation and filling of the LV from the LA, pulmonary vein diastolic forward flow occurs (D wave) when the LV pressure falls during ventricular relaxation and the mitral valve opens [67]. In children, a biphasic forward flow pattern is more common, with S1 and

S2 being indistinguishable in most patients (Fig. 6.20). The usual pulmonary venous Doppler pattern in infants is S-wave dominant [11]. Pulmonary vein stenosis can occur as an isolated lesion or secondary to surgery or other interventions. The techniques described in this chapter for imaging the pulmonary veins in their respective sagittal planes as they approach the LA are ideal for aligning the flow signal to be parallel with the Doppler beam. As in the case of systemic venous obstruction, when assessing for flow abnormalities in the pulmonary veins, evaluating the pattern is often more important than measuring the Doppler gradient (Fig. 6.21). Stenosis primarily manifests as loss of the normal phasic flow pattern [68]. The velocity does not necessarily reflect the severity of the obstruction, as flow may be redistributed away from the lung segment drained by the stenotic vein. In any case, in venous signals, assessing the mean Doppler pressure gradient over several cardiac cycles provides more useful hemodynamic information than measuring the gradient at a single point in the cycle. Magnetic resonance imaging studies have associated unilateral pulmonary vein stenosis with reduced systolic forward flow and diastolic flow reversal in the ipsilateral branch PA, whereas the contralateral PA showed increased systolic flow and continuous forward flow in diastole [69]. If a prominent A wave is observed in the pulmonary venous Doppler, that could indicate either left atrial hypertension from diastolic dysfunction or a dysrhythmia such as a junctional rhythm (Fig. 6.22).

6  Systemic and Pulmonary Venous Anomalies

183

Fig. 6.20  A normal pulmonary venous spectral Doppler tracing is shown. The ‘s’ wave represents systolic forward flow during left ventricular systole (at this time the left atrium is relaxing and hence the pulmonary veins empty into the LA). The ‘d’ wave represents diastolic forward flow

Fig. 6.21  Spectral Doppler tracing showing a loss of the normal phasic venous flow pattern and a mean pressure gradient of nearly 8 mmHg measured over several cardiac cycles, which is consistent with pulmonary venous obstruction

Pulmonary Venous Anomalies  artial Anomalous Pulmonary Venous P Connection General Considerations Partial anomalous pulmonary venous connection (PAPVC), also referred to as partial anomalous pulmonary venous return or PAPVR, occurs infrequently, with an incidence of less than 0.4% in autopsy series [70]. Most commonly, PAPVC is associated with an ASD, which is either secundum

or sinus venosus type in >75% of cases [71–73]. Up to 85% of patients with a sinus venosus defect have PAPVC, compared with 10–15% of patients with a secundum ASD [71]. Often, it is the presence of the associated lesion which leads to detection of the anomalous pulmonary venous drainage. The physiologic disturbance caused by PAPVC depends on several factors, including the number of anomalous pulmonary venous connections involved, site of the connection, status of the pulmonary venous bed, and the presence of an ASD or other defect(s). When a pulmonary vein connects anomalously to the RA or SVC, blood is preferentially

184

T. A. Tacy and S. A. Maskatia

Fig. 6.22  Pulmonary venous spectral Doppler tracing displaying large A-wave reversal (a) in the postoperative period in a patient with a junctional rhythm (s, systolic flow; d, diastolic flow)

shunted to this anomalous vein because of the lower RA pressure, compared with LA pressure, and can produce significant right-sided volume overload. In up to 89% of cases, PAPVC is right-sided [7, 73]. The most common sites for drainage of anomalous right pulmonary veins are the RSVC (36–52%) and the RA (12–52%) [74, 75]. Anomalous right pulmonary veins more commonly involve two or more lobes (75%) than one lobe (25%) [76]. When one or both left pulmonary veins drain anomalously, they most commonly drain into a left vertical vein before entering the left aspect of the LIV, but they may alternatively drain into the CS, or an azygos vein. One anatomic factor that affects detection of this defect is the site of the anomalous pulmonary venous drainage. Pulmonary veins entering the SVC higher than 2 cm above its junction to the RA can be difficult to detect by TEE [76].

Transesophageal Echocardiography Detection rates for partial anomalous pulmonary venous drainage by TEE vary from 60% to 93% [73]. The presence of four pulmonary veins draining normally into the LA does not exclude anomalous additional or accessory pulmonary veins [7]. With anomalous pulmonary venous drainage (either partial or total), color flow Doppler evaluation is an essential part of the examination, although Nyquist limits might need to be adjusted to highlight the anomalous venous drainage. Anomalous right pulmonary veins draining into the SVC are often best visualized by imaging the SVC-RA junction at a transducer angle of ~0° (which transects the SVC in the ME Rt Pulm veins view) and withdrawing the imaging probe while observing the transition from high the RA to the round shape of the SVC. This is performed by initially obtaining

Fig. 6.23  Image depicts a teardrop shape caused by an anomalous right upper pulmonary vein (RUPV) as it enters the superior vena cava (SVC). A change in shape of the SVC from a round to a teardrop shape during real-time imaging is highly suggestive of an anomalous connection of the RUPV to the SVC. This view was obtained as the probe was rotated to the right from the ME Asc Ao SAX view

an ME 4-Ch view and then withdrawing the probe to the ME Asc Ao SAX view. A change from this round shape of the SVC to a teardrop appearance suggests the point of entry of an anomalous right pulmonary vein into the SVC (Fig. 6.23 and Video 6.18) [7]. Similarly, anomalous venous connections to the free wall of the RA can be assessed in this 0° plane by rotating rightward and advancing the probe inferiorly toward the IVC. In this sweep an associated sinus venosus ASD, if present, is usually also seen. The most common form of left-sided PAPVC is one or more left pulmonary veins entering a left vertical vein that drains superiorly into the LIV. The LIV empties into the SVC, which

6  Systemic and Pulmonary Venous Anomalies

may be dilated if the shunt volume is significant. To assess the anomalous drainage, the left pulmonary veins are imaged in a sagittal plane at a transducer angle of ~90°–110° (ME Lt Pulm veins view) as they course toward the LA from the lungs [7]. In the case of this anomaly, instead of draining into the LA, the anomalous pulmonary veins will enter a vessel lateral to the LA, which courses anteriorly to the LPA, and is directed cephalad. Alternatively, one can screen for entry of the left vertical vein into the LIV [7]. As previously described, in the UE Ao Arch LAX view at a transducer angle of ~0°–10°  the LIV will appear anterior to the upper thoracic aorta and transverse arch in its long axis. At this level, rotating the transducer angle to ~70°–90° to obtain the UE Aortic Arch short-axis view (UE Ao Arch SAX) will depict the LIV in short axis and leftward rotation of the transducer shaft should demonstrate any anomalous pulmonary veins, the vertical vein, or both. This view is key for documenting the flow of anomalous left pulmonary veins into a LIV. Rightward rotation of the transducer will result in a long-axis view of the SVC; with probe advancement, it becomes the ME Bicaval view. Although anomalous right pulmonary veins entering the SVC can be seen in this view, the particular site of drainage can make this assessment challenging in some cases. It is important to use a combination of both imaging and color flow Doppler interrogation to evaluate anomalous pulmonary venous drainage.

 ostoperative Considerations in PAPVC P The primary goal of the immediate postoperative TEE is to detect pulmonary venous obstruction and to exclude residual interatrial shunting if a communication was present preoperatively. The potential site(s) of obstruction relates to the surgical technique, in particular how pulmonary venous blood is diverted to the LA. For right sided PAPVR associated with a sinus venosus ASD, if the site of drainage of the

Fig. 6.24  Panel a, ME 4-Ch view with clockwise probe rotation after a Warden procedure, depicting the laminar flow across the rerouted anomalous right pulmonary vein by color Doppler (red flow, long arrow) and the atrial septal patch (arrowhead). Panel b,  ME Bicaval

185

anomalous pulmonary vein(s) into the SVC is well above the RA, the SVC may be transected above the level of the entrance of the anomalous vein(s). The proximal portion of the SVC is anastomosed to the RAA (the cardiac end of the SVC is suture closed), and the sinus venosus ASD is then closed in such a way that the pulmonary venous blood flow which returned above the level of the SVC-RA junction (cardiac end of SVC) is routed or baffled through the defect into the LA (Fig. 6.24a and Video 6.19). This procedure is termed the “Warden procedure” [77]. When a two-patch repair is employed, one patch is used to tunnel the pulmonary venous return through the ASD into the LA, and a second patch is placed to augment flow through the SVC.  In some cases, the two techniques are combined in a Warden procedure, and the SVC  to  RAA anastomosis is patched to minimize potential for future obstruction. After any type of repair, it is vital to ensure the absence of obstruction throughout the systemic and pulmonary venous pathways as described above. Depending on their geometry after baffle repair, the systemic and pulmonary venous connections are best assessed by using a combination of views that may include the ME 4-Ch, ME Asc Ao SAX, ME Bicaval, ME Rt Pulm veins, and DTG Atr Sept views, and their respective modifications (refer to section on normal systemic and pulmonary vein imaging) (Fig. 6.25 and Videos 6.20, 6.21, 6.22). Of note, the systemic venous connection via the RAA is typically anterior to the normal site of SVC drainage to the RA, and it may be challenging to achieve enough signal to adequately assess this anastomosis for obstruction (Fig.  6.24b and Video 6.23). Deep transgastric imaging can be helpful in this regard. For left-sided PAPVR, the postoperative TEE evaluation should be guided by the procedure undertaken. If the anomalous veins were anastomosed directly to the LA, this region would represent the main focus of the examination.

view showing flow across the anterior superior vena cava (SVC) to right atrial appendage connection  (blue signal noted by arrow). LA left atrium, RA right atrium

186

T. A. Tacy and S. A. Maskatia

Fig. 6.25  Panel a,  midesophageal view displaying color Doppler interrogation across the pulmonary venous baffle after two-patch repair of a sinus venosus atrial septal defect and partial anomalous pulmonary venous connection. Panel b,  color flow imaging across the superior vena cava in the same patient. Panel c, ME Bicaval view in a different

patient displaying the patch that incorporates the anomalous pulmonary venous return into the left atrium (red color flow signal) while separating the atria. Panel d, corresponding spectral Doppler of rerouted anomalous pulmonary flow into the left atrium. Note the normal, low velocity phasic flow

Scimitar Syndrome

and severity of associated defects, heart failure, and pulmonary hypertension—and, therefore, significant mortality [81]. Surgery usually consists of baffling or anastomosing the anomalous right-sided pulmonary veins to the LA.  In some cases, feeding arterial vessels to the right lung are also ligated. Interventions in affected patients can also be catheter-­based  (e.g., coil embolization of aortopulmonary collateral vessel). A related entity, often termed “meandering right pulmonary vein”, refers to right pulmonary venous drainage via a Scimitar vein into the LA. Affected patients often have other features of Scimitar syndrome, such as right pulmonary hypoplasia, but to a milder degree [82].

General Considerations Scimitar syndrome is a rare condition consisting of either partial or total anomalous pulmonary venous drainage from the right lung into the IVC [78]. This syndrome is often associated with several other abnormalities, including a hypoplastic right lung and RPA, anomalous systemic arterial blood supply to the right lung from the abdominal aorta with or without pulmonary sequestration, abnormalities of the tracheobronchial architecture and of lung lobation, pulmonary hypoplasia, rightward displacement of the heart (mesocardia or dextrocardia), and pulmonary hypertension [79]. The anomalous pulmonary vein creates a curvilinear shadow on the chest radiograph that resembles a Turkish sword, hence the term “Scimitar syndrome”. Affected patients present most frequently either in infancy or adulthood, depending on the clinical sequelae. It has been suggested that the adult form of the syndrome has no serious clinical manifestations, and usually, no therapy is indicated [80]. The infantile variant is marked by a higher incidence

Transesophageal Echocardiography Especially in the adult, the use of TEE or other diagnostic modalities is mandatory for confirming suspected Scimitar syndrome, particularly to determine the exact site of the anomalous pulmonary venous connection to the IVC [83]. Imaging of the anomalous right pulmonary venous connection can begin at a transducer angle of ~0° by

6  Systemic and Pulmonary Venous Anomalies

187

ventricular hypoplasia, leftward deviation of the septum primum was observed by echocardiography in 37% of patients with hypoplastic left heart syndrome [87]. When the septum deviates superiorly and posteriorly, normally connected right pulmonary veins can drain into the RA, yet the effects of this alteration on left atrioventricular valve size may be minimal [86].

Fig. 6.26  DTG Atr Sept view (transducer angle of 110°) depicting turbulent color flow from an anomalous right lower pulmonary vein (RLPV) or Scimitar vein, draining into the posterior aspect of the inferior vena cava (IVC) just above the diaphragm. RA right atrium

placing the probe in a TG position. The probe is further advanced into the stomach to obtain the DTG five-chamber view  (DTG 5-Ch; transducer angle ~0°–20°). From this plane, the transducer angle is rotated forward to display the DTG RV outflow view (DTG RVOT), obtained at ~50°–90°. Rightward probe-shaft rotation allows the entire length of the IVC to be seen in the DTG Atr Sept view or by rotating the transducer angle forward from this view to ~120°–140°. One can then follow the IVC, looking for turbulent flow in the anomalous Scimitar pulmonary vein, either below or above the level of the diaphragm (Fig. 6.26 and Video 6.24) [83]. The transducer angle can then be rotated back to 0° for further delineation of the Scimitar vein in an orthogonal plane. Alternatively, in the esophagus (while at a transducer angle of ~90°) in the ME Bicaval view, further probe advancement may allow for the anomalous vein to be visualized in the TG IVC/Hep veins view as it drains into the IVC.

 artial Anomalous Pulmonary Venous P Drainage Due to Malposition of Septum Primum General Considerations A variant in atrial septal morphology, leftward deviation of the  septum primum, can result in anomalous drainage of some of the pulmonary veins despite their normal attachment to the atrium [84, 85]. Anomalous attachment of the superior portion of the septum primum has physiologic consequences [86]. When the septum deviates superiorly and anteriorly, flow through the foramen may be restricted, which can lead to hypoplasia of the left atrioventricular valve. In one series of patients with left

Transesophageal Echocardiography In these cases, the pulmonary veins connect normally, but because of the atrial septal deviation, the flow from several or all of the pulmonary veins may be directed to the RA (in the case of superior and posterior deviation of the interatrial septum) or may not be affected at all. Thus, the TEE examination should focus on imaging the septal configuration once normal pulmonary venous attachment has been recognized. Beginning in the transverse plane (~0°) at the ME level, one can start from a more inferior position within the esophagus, such as the level used to view the CS as it courses through the posterior left atrial wall (ME 4-Ch view with probe retroflexion). In cases of leftward and posterior deviation of the septum, as the probe is withdrawn, one can observe almost immediately the abrupt turn of the septum primum toward the left lateral atrial wall. The appearance of the deviated atrial septum will resemble a cor triatriatum membrane except that the septal wall of the superior chamber is absent. All pulmonary veins can be appreciated entering the LA normally, but color flow Doppler shows that their flow is directed to the RA. In the case of leftward and anterior deviation of septum primum, one must withdraw the TEE probe almost to the level of the roof of the LA to observe the leftward “curling” of the septum primum (Fig. 6.27 and Video 6.25). The distance between this septum and the right pulmonary veins can be appreciated, as the entrance of the right pulmonary veins occurs more posteriorly than the affected septum. Often, the septal deviation results in restricted flow across the foramen ovale. The color Doppler signal of the restricted atrial-level shunt originates much farther leftward than and superiorly to the shunt itself, so the shunt can be mistaken for left pulmonary venous flow if the echocardiographer is not aware of the position of the septum primum.

 otal Anomalous Pulmonary Venous T Connection General Considerations Total anomalous pulmonary venous connection (TAPVC), also referred to as total anomalous pulmonary venous return or TAPVR, is defined as abnormal drainage of the pulmonary venous blood into the systemic venous system. This malformation represents about 2.2% of all CHD [88].

188

T. A. Tacy and S. A. Maskatia

Fig. 6.27  ME 4-Ch views in an infant with hypoplastic left heart syndrome, showing the configuration of the septum primum (indicated by arrows). Panel a, the normal-appearing orientation of the septum

primum is shown. Panel b, the septum is shifted leftward after the probe is withdrawn within the esophagus

The classification of TAPVC is based on the site of the abnormal pulmonary venous drainage. The different types of TAPVC are supracardiac (45–55%), cardiac (15–20%), infracardiac (15–20%), and mixed (5–10%) [89]. Individual pulmonary vein size at diagnosis is a strong, independent predictor of survival in patients with TAPVC.  An indexed pulmonary vein diameter sum of about ≤50 mm/m2 ( 0.14 and peak systolic aorta after the Lecompte maneuver. The left pulmonary artery (LPA) appears smaller than the RPA in this infant. This view is optimal for velocity  >  0.6  cm/s have been associated with the need for color flow and spectral Doppler assessment of the pulmonary arteries. surgical revision [62]. Imaging the reimplanted CAs has been Neo PA, neo-pulmonary artery shown to be predictive of the need for re-operation or of an adverse myocardial event if abnormal [63]. A Doppler velocand a plan for return to bypass for specific revision is impor- ity  >  1  m/s measured at a CA origin can indicate proximal tant to ensure the best surgical outcome. vessel issues such as mechanical problems with the relocation In the postoperative evaluation of the patient with transpo- or kinking. Retrograde flow in the LMCA can be associated sition and a doubly-committed VSD, particular attention needs with adverse myocardial events [63]. On occasion, the reimto be paid to interrogation of semilunar valve function. This is planted CA arising from the anterior neo-aortic sinus is combecause patch closure of this type of VSD is challenged by pressed by the straddling branch PAs, frequently the left PA, lack of conal tissue between the semilunar valves and place- and this possibility needs to be considered if the CA is reloment of the patch can distort either of the valves. A small VSD cated into an anterior location and cardiac function deteriopatch leak should be evaluated for size and peak pressure gra- rates while coming off CPB or during sternal closure. dient between the ventricles. Larger defects with a small venThe evaluation of global and regional systolic ventricular tricular pressure drop are more likely to be hemodynamically function is critical in the ASO and their analysis can add to significant and usually require revision. In ­general, a residual concerns for adequacy of the CA reimplantation (Video defect measuring ≥4 mm by TEE is likely to require immedi- 15.28). Some amount of global LV dysfunction can be ate reoperation, while a 3 mm defect may be significant and expected early after surgery, especially in the older infant with should trigger additional intraoperative hemodynamic evalua- an intact ventricular septum and a deconditioned LV. This settion [57]. A more complex type of VSD is the intramural ting needs to be differentiated from a complication associated defect which occurs between the VSD patch and right ven- with coronary transfer. In the operating room this may require tricular trabeculations when the patch is sewn onto these tra- frequent evaluation of global and segmental LV function and beculations rather than the RV free wall (also refer to Chaps. CA flows at multiple stages during separation from CPB, in 10 and 14) [58–61]. These types of defects can be difficult to response to inotrope administration, initiation of nitric oxide identify as they typically occur in an anterior plane and/or the therapy (if indicated), and finally chest closure. While post peripheral location is such that turbulent color flow is often the bypass myocardial dysfunction resulting from the ischemic earliest clue that a residual VSD might be present. This defect insult (i.e., aortic clamping) and other factors related to the may enlarge over time and should be addressed prior to leav- intervention (e.g., myocardial edema) gradually improves during the operating room, although precise surgical identifica- ing the postoperative period, this is not the case for ventricular tion and localization can be challenging. Supplemental data dysfunction accompanying CA stenosis or occlusion [64]. should be considered, including direct RV pressure measure- Thus, compromised myocardial blood flow as a result of the ments by the surgeon and/or intraoperative assessment of the surgical intervention should be considered in any infant with pulmonary to systemic blood flow ratio (Qp:Qs) in cases ongoing low cardiac output syndrome, electrocardiographic where the information is equivocal, or it is unclear whether the abnormalities (i.e., ST-segment depression), ventricular risk-benefit ratio of additional CPB time is warranted. rhythm disturbances, and/or echocardiographic evidence of Coronary artery imaging post reimplantation should significant regional wall motion abnormality. In this setting, include 2D imaging as well as color and spectral Doppler. alternative confirmatory imaging modalities should be per-

15  Transposition Complexes

Fig. 15.29  ME AoV SAX views post ASO displaying the origins and proximal course of the right (RCA) and left (LCA) coronary arteries from the aortic (Ao) root by 2D imaging and color flow Doppler. Note the low Nyquist limit setting to enhance detection of coronary flow. In

497

this image, the RCA appears patent with laminar antegrade flow. The origin of the LCA, however, is not well seen and color Doppler depicts turbulent flow suggestive of proximal obstruction

Fig. 15.30  Same image as shown in Fig. 15.29 with pulsed-wave Doppler across origin of the right coronary artery shows predominantly diastolic antegrade flow with a low peak velocity and return to baseline

formed without delay. This aspect is a relative limitation of all echo-based imaging modalities and prompt confirmation of CA patency in the cardiac catheterization laboratory or by chest computed tomography should be considered. Global assessment of ventricular performance should be undertaken in multiple views as described in Chap. 5. Segmental wall motion evaluation, as also addressed in the same chapter, is assessed primarily by navigating between

the midesophageal (ME 4-Ch, ME 2-Ch, and ME LAX; Video 15.28) and the transgastric (TG Basal SAX, TG Mid Pap SAX, TG Apical SAX) views. The importance of segmental wall motion evaluation in this setting was highlighted in a prospective study in neonates undergoing the ASO.  It was concluded that segmental wall motion abnormalities that persisted at the completion of the procedure and were present in multiple myocardial segments, correlated with isch-

498

A. H. Bhat and B. D. Soriano

Fig. 15.31  Same image as shown in Fig. 15.29 with pulsed-wave Doppler interrogation across the left main coronary artery shows an obstructive flow pattern characterized by a high peak velocity and of lack of return to baseline suggesting need for revision of the translocated vessel

emia [65]. Significant mitral regurgitation can accompany myocardial ischemia due to papillary muscle ischemia and represents another clue to inadequate myocardial perfusion potentially related to the CA translocation. Evaluation for pulmonary hypertension is particularly important in patients with a large or multiple VSDs, aortopulmonary collateral vessels, or a prior failing LV. Quantitative assessment of RV systolic pressure requires interrogation of the tricuspid regurgitation jet or residual VSD jet peak velocities. Septal configuration may indicate relative pressures in the pulmonary and systemic vascular beds [66]. Of course, pulmonary outflow tract obstruction must be considered/ ruled out in order to make any determination of pulmonary hypertension using these parameters. Postoperative TEE Assessment after Senning or Mustard Procedure A comprehensive evaluation of atrial pathways after an atrial switch procedure usually begins in the ME 4-Ch view. The examination is best achieved by tracking blood flow from the systemic and pulmonary veins separately from their proximal course in the mediastinum, their entrance into the heart, and as these flows course through the regions of the baffle, across AV valves, and into the respective systemic or pulmonary ventricles. From the ME 4-Ch view, some degree of leftward or counterclockwise rotation would display the left pulmonary veins as they enter the pulmonary venous portion of the baffle. In the same plane, rightward or clockwise rotation would show the entrance of the right pulmonary veins into the pulmonary venous atrium. These views are in essence the modified ME left pulmonary veins (mod ME Lt Pulm veins; transducer angle ~0°) and the ME right pulmonary veins (ME Rt Pulm veins; transducer angle ~0°) views respectively. This is not significantly different than as described in Chaps. 4 and 6 for the TEE evaluation

Fig. 15.32  ME 4-Ch view of a patient after an atrial switch operation for transposition demonstrating the pulmonary venous channel (PVC) as it makes its way towards the tricuspid valve (TV). In this patient, the pathway is unobstructed. Note a pacing catheter in the superior limb of the baffle

of the pulmonary veins in the normal heart. The value of TEE in the assessment of individual pulmonary venous flow after atrial baffle procedures has been shown [67]. Flow across the pulmonary venous limb of the baffle as it wraps around the systemic limbs  should then be evaluated by adjusting the imaging plane by means of rotating the transducer shaft (Fig. 15.32, Video 15.29). The ME Bicaval and ME Mod Bicaval TV views are helpful in demonstrating both limbs (superior and inferior) of the systemic venous baffle. This view can be followed to outline the systemic venous portion of the baffle as it courses relative to the pulmonary venous portion (Figs.  15.33, 15.34, and 15.35, Videos 15.30 and 15.31). From this view, rotating the probe to the left or counterclockwise, shows the course of the systemic venous baffle as its flow enters the mitral valve. The DTG views can track the inferior vena cava (IVC) as fol-

15  Transposition Complexes

499

lows. Once a DTG Atr Sept view has been obtained rightward probe rotation and forward rotation of transducer angle to ~120°–130° allows the IVC to come into view. Using a modified TG IVC/Hep veins view (transducer angle ~80°–100°) would also be useful to visualize the IVC connection to systemic baffle. As the probe is gradually withdrawn into the mid esophagus, and the transducer plane adjusted as needed, the inferior limb of the baffle can be followed as blood flow makes its way to the systemic venous atrium and across the mitral valve. Once the tip of the probe is in the ME region, the ME 4-Ch, ME-2Ch, and ME LAX

Fig. 15.35  ME view (transducer angle 13°) in the same patient after atrial switch operation shown in Figs.  15.32, 15.33, and 15.34. This image demonstrates significant narrowing of the superior limb of the systemic venous channel (Sup L) as it crosses posterior to the pulmonary artery (PA). Transvenous pacing wires are seen (echo-bright structures) within the Sup L, likely contributing to the obstruction. PVC pulmonary venous channel

Fig. 15.33  ME Bicaval view with rightward turning of the TEE probe in a patient post atrial switch operation with superior systemic venous limb obstruction. In this view, both superior (SVC) and inferior (IVC) limbs of the systemic venous channel are seen with the pulmonary venous channel (PVC) coursing in between. Pacing wires are seen in the superior limb

Fig. 15.34  Modified ME RV In-Out color Doppler image in the same patient shown in Figs. 15.32 and 15.33 after an atrial switch operation with superior limb obstruction. Aliasing of the color flow is seen in the superior limb of the channel

views can be used to also assess ventricular function and the outflow tracts. Use of color and spectral Doppler at each of the proximal locations of these veins/pathways and across any regions of turbulence can determine if there is important obstruction and also assist in the determination of baffle leaks (Fig. 15.36, Video 15.32). TEE guidance of residual baffle leaks is particularly useful during transcatheter device occlusion of these atrial level communications as noted in Chap. 21 (Fig. 15.37 and Video 15.33). Multiple TEE probe and transducer angle manipulations are likely required to demonstrate the course of the systemic and pulmonary venous pathways. The use of long video loops and sweeps along with color compare features available on most echocardiographic systems, as well as options available in 3D TEE imaging, can maximize spatial understanding of these complex pathways. Once their course has been understood, a detailed evaluation for stenosis and shunts should be undertaken as these may impact the eventual functioning of this type of circulation. The tricuspid valve and the RV need to be evaluated, given that they are now the systemic AV valve and ventricle. Outcome and eventual failure after the atrial switch procedures are closely related to the severity of tricuspid regurgitation immediately after the surgical procedure. Severe tricuspid regurgitation has been shown to be a precursor and surrogate of impending RV failure in the immediate or long term [68, 69].  The ventricular septum tends to bow toward the LV in these cases and can cause LVOT obstruction which needs to be assessed as well. Finally, the semilunar valves need to be examined for competency.

500

a

A. H. Bhat and B. D. Soriano

b

Fig. 15.36  ME modified view (transducer angle 91°) in an adult with history of  atrial switch operation for transposition  in infancy.  Panel a, displays a communication or baffle leak (arrow) between the inferior

vena cava (IVC) portion of the systemic venous channel and the pulmonary venous channel (PVC) by 2D imaging. Panel b, demonstates the left-to right shunt by color flow Doppler around this region

Fig. 15.37  ME modified view in the same patient shown in Fig. 15.36 with a baffle leak  post atrial switch operation. The image depicts an Amplatzer occluder device (arrow) just prior to deployment

Fig. 15.38  ME 4-Ch view with superimposed color flow imaging shows residual ventricular septal defect (VSD, arrow) post Nikaidoh operation for complex transposition, prompting return to bypass. LV left ventricle, RA right atrium, RV right ventricle

Postoperative TEE Assessment after Complex Repairs (Rastelli and Nikaidoh Procedure) The TEE imaging protocol in repairs of complex transposition with associated VSD and pulmonary stenosis/LVOT obstruction requires multiple views and sweeps. Assessment for residual VSD is required in all procedures (Fig.  15.38, Videos 15.34 and 15.35). The goal of the exam is to assess for patch leaks or other residual defects located in the posterior interventricular septum that may be related to the posterior circumference of the VSD patch or to identify previously unrecognized separate defects. Evaluation for LVOT obstruc-

tion along the long intraventricular baffle is needed after a Rastelli-type repair due to the distance between the LV and the rightward aorta. The ME 5-Ch and ME LAX, as well as the DTG outflow tract (DTG 5-Ch and DTG RVOT) views are useful for this interrogation. Transducer angulation may need refinement in order to obtain modified views that display the entire outflow tracts by 2D and color imaging and for optimal alignment of spectral Doppler. Residual LVOT obstruction is less likely in the Nikaidoh procedure since the conal septum is divided and the operation allows for a better alignment of the LVOT when compared to other surgical

15  Transposition Complexes

options (Fig. 15.39 and Video 15.36). Reconstruction of the RVOT in these complex procedures (e.g., conduit from the RV to the MPA in the Rastelli operation), as well as branch PA anatomy, can be interrogated in the UE PA, UE Ao Arch SAX,  ME RV In-Out, ME LAX, and DTG RVOT views. Right ventricle to PA continuity is established directly in the REV procedure (Fig. 15.40, Video 15.37). In some cases, the

501

CAs may be reimplanted and the exam should also include their assessment. Even if the CAs are not translocated, flow in these vessels should be confirmed because  aortic root translocation can cause torsion and obstruction (Fig. 15.41).

Fig. 15.39  ME LAX view of the newly reconstructed, unobstructed LVOT after a Nikaidoh procedure in the patient shown in Fig. 15.38. The aortic root has been positioned in a more anatomically appropriate location. Ao aorta, LA left atrium, LV left ventricle, PA pulmonary artery, RV right ventricle

Role of TEE in Late Reintervention/Reoperation after Arterial Switch Operation Residual and recurrent obstruction at any of multiple levels through the RVOT are the most frequent indications for reoperation and reintervention in about 10% of cases after the ASO [70, 71]. The Lecompte maneuver brings the PA branches in front of the Asc Ao and a combination of dilatation of the neo-aortic root, stenosis along the neo-PA anastomosis, stretching of the branches, and compression between the sternum and aorta can lead to main and branch PA stenosis. Both transthoracic and transesophageal modalities may be inadequate for good spatial detail in the suprapulmonary and branch PA regions, and alternative imaging approaches are recommended to obtain an accurate road map of their anatomy as described in the Multimodality Imaging Guidelines of Patients with TGA [55]. The American Heart Association and American College of Cardiology (AHA/ ACC) Guideline for the Management of Adults with Congenital Heart Disease recommends surgical repair of RVOT obstruction in symptomatic patients with an RV systolic pressure (RVSP) > 60 mm Hg or asymptomatic patients

Fig. 15.40  Color compare ME LAX images in the same patient shown in Figs. 15.38 and 15.39 following Nikaidoh procedure and anastomosis of the native main pulmonary artery (MPA) to the right ventricle (RV)

without intervening conduit (REV procedure). While the ME views are excellent for evaluating this aspect of the anatomy, DTG views are ideal for optimal spectral Doppler interrogation. Ao aorta, LA left atrium

502

A. H. Bhat and B. D. Soriano

Fig. 15.41  ME AoV SAX view showing color flow Doppler across the right coronary artery post Nikaidoh operation. In this case, the proximal coronary arteries were mobilized to facilitate the posterior translocation of the aortic root but did not have to be reimplanted

with RVSP > 80 mm Hg [72]. Similarly, European Society of Cardiology guidelines support surgical repair in symptomatic patients with RVOT obstruction and RVSP > 60 mm Hg or in asymptomatic patients with RV dysfunction [73]. TEE is an important imaging modality to support interventions such as balloon angioplasty or stenting in the cardiac catheterization laboratory and certainly for surgical revisions if the lesion is not amenable to a catheter-based intervention. After arterial switch surgery, the native pulmonary root functions as the neo-aortic root and is prone to dilatation. Prior banding of the MPA, increased transpulmonary flow, as well as anterior conal deviation in a subpulmonary VSD may predispose to a dilated native pulmonary annulus and root before surgical intervention [74]. There is a greater incidence of progressive neo-aortic root dilation in this group as well as those who have late surgical repairs. Incompetence of the neoaortic valve may be secondary to its dilated annulus and resultant noncoaptation of the leaflets or from the inherent relative weakness of this native pulmonary valve to withstand systemic arterial pressure. However, severe regurgitation appears to be rare [75]. Neo-aortic root dilatation or dysfunction are also long-term complications of the ASO but less common indications for reintervention [76–78]. Neo-­aortic root dilatation is unlikely to lead to dissection. Nevertheless, Z scores of the neoaortic root obtained by TTE allow for patient surveillance to determine whether aortic root size is within or out of proportion to somatic growth. Aortic valve pathologies are also readily evaluated by TEE for severity of disease, preoperative planning, and finally intraoperative guidance. Neo-aortic valve repair and replacement are primarily based on disease severity,  degree of LV dilation/dysfunction and symptomatology, and represent late  interventions after the ASO.  In the adult patient these clinical problems are managed according to the AHA/ACC Guidelines for the Management of Valvular Heart Disease [79, 80]. TEE is also an important imaging modality to

determine aortic root enlargement as well as to assist intraoperatively in the surgical replacement of a neo-aortic root if it exceeds the threshold of 55 mm in an average adult [81]. Coronary artery complications are an important cause of both early and late mortality. This can be a problem immediately after surgery in the first few minutes after separation from CPB. A second wave of CA events arise in the first few years following intervention with some ongoing risk into the later years [82–84]. Late coronary events may be attributed to intimal thickening and stretching as the patient ages. Twisting may occur at the coronary ostia, especially during periods of rapid somatic growth. While segmental dyskinesia on TTE is an early clue identified upon surveillance, definitive tests such as coronary angiography, stress-perfusion imaging, and nuclear medicine studies may be indicated [55]. TEE is of limited use in this situation but can be helpful in the intraoperative setting during coronary interventions. Role of TEE in Late Reintervention/Reoperation after Atrial Switch Operation TEE plays a major role in the care of post-atrial switch patients, given the fact that it provides outstanding real-time imaging of the intra-atrial baffle (superior to other diagnostic modalities), as well as the fact that these patients tend to be older and TTE might have limited utility. A high prevalence of baffle leaks has been reported in adults who have previously undergone atrial switch procedures [85]. TEE has better ability to seek and resolve the  location of baffle leaks in complex atrial switch pathways as compated to TTE, particularly with the use of agitated saline contrast, since it is more suited to assess posterior connections and surgical pathways. In fact, it has been reported to be superior to cardiac magnetic resonance imaging for this indication [86]. When baffle leaks are present the direction of shunting is dependent on the relative atrial pressures but is unlikely to be an independent cause for reoperation.

15  Transposition Complexes

Obstruction to the superior portion of the systemic venous baffle (superior vena cava or SVC limb), though more common than IVC limb obstruction, is still overall quite rare and typically develops within weeks to several months postoperatively in those intervened during the neonatal period. Systemic baffle obstruction is more commonly seen after the Mustard operation (10-40%) as compared to the Senning atrial switch procedure (40  mmHg, RV-to-LV pressure ratio > 85%) occurred in 35% of patients after the intervention. Only 12% of these patients had fixed RVOT obstruction, which required immediate surgical revision; the remaining 88% of patients had dynamic RVOT obstruction, which was not judged to require surgical reintervention. Interestingly, irrespective of the severity of the obstruction detected intraoperatively, outflow gradients declined sharply on follow-up (mean 18.5 months after surgery). No reoperations or late deaths were reported. The authors indicated that intraoperative echocardiography was helpful in distinguishing fixed from dynamic obstruction, thereby obviating needless revisions. They also concluded that in this patient group, dynamic RVOT gradients declined significantly irrespective of their initial severity. The implication of this study is that gradients by themselves, regardless of their severity, cannot be used in isolation to judge the need for surgical revision. One of the major applications of intraoperative TEE is in the evaluation of residual intracardiac shunting after repair of ventricular septal defects (VSD) and assessment of the potential need to return to bypass. The finding of residual ventricular-level shunting can present a clinical dilemma in some cases regarding its hemodynamic significance and need for reoperation. A few studies have addressed this issue by examining frequency, significance, and implications of residual VSDs detected intraoperatively. Yang et al. noted a prevalence of residual shunting in a third of patients undergoing VSD closure (96 out of 294) [219]. However, most defects were insignificant, in fact, two-thirds closed by hospital discharge. The study suggested that a residual VSD that measures ≥4 mm or a shunt greater than 1.5:1 should be considered for immediate reoperation while a 3  mm defect requires additional information to determine hemodynamic significance. A retrospective review by Hanna et al. investigated the predictive value of the diagnosis of a residual VSD identified by intraoperative TEE in 690 patients who were followed longitudinally [215]. In their study, the detection of a residual shunt in the operating room was also a fairly common finding, occurring in 37% of the cohort. In the majority of cases, however, the defect was trivial and resolved spontaneously. The study found that the detection of a residual shunt at the site of the repair carried an overall positive predictive value of only 15% in the long term and noted that

W. C. Miller-Hance and A. Vegas

most residual defects need surgical intervention only rarely. These two studies provide data regarding the eventual course of residual shunts detected intraoperatively after VSD closure and support the clinical impression of the infrequent need to return to bypass in most cases.

Correlation of Intraoperative and Postoperative Echocardiographic Findings Few data show a correlation between intraoperative and postoperative echocardiographic information, and some literature in fact points to disagreement in some cases [220, 221]. It is not altogether surprising that a discrepancy might exist between intraoperative and postoperative echocardiographic findings. As noted above, changing hemodynamic conditions in the operating room likely affect clinical findings, particularly assessments of valvar stenosis and regurgitation. Moreover, the quality of echocardiographic imaging can differ substantially between the intraoperative TEE and postoperative TTE studies. Finally, changes can occasionally occur in a surgical repair, even within a few days postoperatively, and these might also affect its echocardiographic appearance. Lee et al. examined the validity of intraoperative TEE in predicting the severity of mitral regurgitation (MR) at follow-­up in patients after complete repair of atrioventricular septal defects [220]. The MR severity was quantified as the ratio of the maximum MR jet area by color flow Doppler imaging to the left atrial area on 2D imaging, using biplane TEE after weaning from CPB but before chest closure. A discrepancy in the MR grade occurred in 47% of patients, with the majority having a higher MR grade on follow-up. This suggested that the MR grade as assessed by TEE ­immediately after surgery may not predict the degree of regurgitation at follow-up. Honjo et al. evaluated 42 consecutive children who underwent valve repairs and identified significant discrepancies (disagreement in 64%) between the intraoperative TEE and postoperative TTE findings before hospital discharge [221]. In most cases, residual atrioventricular valve regurgitation was underestimated in the operating room, whereas there was reasonable agreement between intraoperative and postoperative estimates of aortic valve regurgitation. A retrospective study aimed to examine the routine practice of predischage TTE after congenital heart surgery found that abnormal findings on this examination were very common (51%; 265 out of the 462 patients) [222]. The findings included valve regurgitation, hemodynamic obstruction, ventricular dysfunction, unintended shunt, or pericardial effusion. In some patients, the abnormalities were of greater than mild severity and were associated with adverse clinical

18  Intraoperative and Postoperative Applications

599

Table 18.4  Postoperative indications for transesophageal echocardiography •  Assessing cardiovascular anatomy and function when TTE is not diagnostic •  Evaluating potential shunts when TTE images are inadequate, particularly in patients with unexplained cyanosis •  Assessing mechanism of right or left ventricular outflow tract obstruction •  Assessing valvar stenosis and/or regurgitation, severity and mechanisms •  Evaluating complex intracardiac or extracardiac baffles (e.g., atrial baffles procedures such as post Senning or Mustard operation, Fontan) •  Evaluating for a cardiovascular source of embolic event •  Evaluating for intracardiac thrombus before cardioversion for atrial flutter/fibrillation, radiofrequency ablation, or both •  Evaluating suspected endocarditis (vegetation or abscess) • Re-evaluating infective endocarditis in patients with virulent organism, severe hemodynamic lesion, aortic involvement, persistent bacteremia, a change in clinical status, or symptomatic deterioration •  Evaluating prosthetic valve with suspected dysfunction or thrombosis or a change in clinical status • Re-evaluating prior TEE finding for interval change (e.g., resolution of vegetation after antimicrobial therapy, thrombus status after anticoagulation) • Evaluating pericardial conditions (e.g., pericardial mass, effusion, constrictive pericarditis, effusive-constrictive conditions, patients post-cardiac surgery, or suspected pericardial tamponade) •  Evaluating suspected aortic disease (e.g., dissection) •  Evaluating hypotension or hemodynamic instability of uncertain or suspected cardiac origin •  Guiding transcatheter interventions after surgery •  Guiding placement of mechanical circulatory assist devices

events. When the results of intraoperative TEE at the conclusion of surgery were compared with TTE findings prior to hospital discharge, only fair to moderate concordance was identified. These results underscore the fact that postoperative TTE is often necessary, and rarely should intraoperative TEE be the only echocardiographic study obtained after surgery.

 EE for Evaluation in the Postoperative T Setting The role of TEE in the cardiac critical care unit and other postoperative settings has been extensively documented at many centers (refer to Chap. 19 for in depth discussion) [223–231]. The use of TEE in critically ill patients is more common in adults. Since children generally have more favorable transthoracic windows, adequate information can often be obtained by standard TTE.  However, in postoperative pediatric patients, the superior resolution of TEE can facilitate morphologic and functional assessment when TTE is suboptimal because of lung interference, an open sternum, or the presence of bandages [232, 233]. Mechanical circulatory support in the pediatric age group has received increasing attention in recent years as size-­appropriate hardware has become available. Applying existing technologies and novel devices can help address circulatory failure in patients with CHD and other disorders. The use of TEE in the operating room, critical care unit, or both facilitates care of these patients by aiding cannula and device positioning, assessing cardiac chamber decompression, evaluating ventricular loading conditions, and quantifying recovery of myocardial function (refer to Chap. 20) [234–236]. In addition, TEE can help optimize pharmacologic and other medical therapies and provide information regarding a patient’s readiness for weaning from support.

Although several investigations have documented the value of TEE in assessing cardiac output and systemic vascular resistance in critically ill adult patients, these types of assessments have not yet been validated in children [237, 238]. After congenital cardiac surgery, TEE can assist in the further characterization of unexpected or unusual findings or abnormalities that were suspected but not adequately defined by TTE. A subset of patients with an unanticipated or complicated immediate postoperative course may require further diagnostic evaluation; in some cases, the diagnostic capabilities of TEE can obviate the need for alternative, and sometimes more invasive, imaging studies [239]. The American College of Cardiology Foundation and the American Society of Echocardiography, in combination with key specialty and subspecialty societies, published an appropriateness review for the use of echocardiography in 2007 [240]. The report was subsequently updated in 2011 [241]. The writing groups rated clinical indications in adults (age 18  years or older) in both inpatient and outpatient clinical settings. These publications were based on the general assumption that TEE is used primarily as an adjunct or subsequent test to TTE, but indications for TEE as an initial or supplemental study were also considered. Intraoperative applications were not addressed by the writing group. With respect to postoperative indications for TEE, those generally considered appropriate by both, the working group and in recently published pediatric and congenital TEE guidelines, are listed in Table 18.4 [3, 242]. Data regarding the applications of TEE in children in the immediate postoperative period are quite limited, and indications comparable to those in the adult patient have not yet been clearly defined. Nonetheless, many situations are analogous to those encountered in adults, and the clinical experience suggests that TEE, when used in a judicious and appropriate manner, can provide real and important benefits in the postoperative and critical care settings (refer to Chap. 19).

600

Summary The overwhelming contributions of TEE have led to this imaging tool becoming the standard of care for intraoperative assessment of most congenital heart repairs and surgical interventions for pediatric acquired heart disease at many centers. Extensive experience has documented a substantial overall impact on surgical decision-making and significant applications that include surgical planning, evaluating the intervention, and guiding surgical revision as necessary. Contributions to anesthetic care include real-time ­monitoring of ventricular filling and myocardial performance, ensuring adequate cardiac deairing, and optimizing hemodynamic management strategies. Intraoperative TEE assists in the formulation and optimization of plans for postoperative care and provides important postoperative information. Although it has not been formally assessed in a rigorous scientific manner, the experience regarding the intraoperative and postoperative contributions of TEE is compelling enough to conclude that this technology has a substantial positive impact on clinical outcome in pediatric patients and adults with CHD.

Questions and Answers 1. All of the following devices allow imaging of the heart in transverse or horizontal planes EXCEPT a. Biplane TEE probe b. 3D TEE Probe c. Micro-multiplane TEE probe d. Intracardiac catheter (ICE) when used via the transesophageal approach e. Monoplane TEE probe Answer: d Explanation: All standard TEE imaging probes allow imaging in the transverse (horizontal or 0°) plane except for the ICE catheter, which incorporates a single longitudinal (vertical or 90°) imaging plane. 2. Among adults with CHD, which of the following is considered one of the most frequent  indications for TEE imaging a. Evaluating suspected intracardiac  thrombus when TTE is nondiagnostic b. Routine evaluation of an  asymptomatic patient with corrected ventricular septal defect who is lost to follow-up c. Evaluating native or prosthetic valve in a patient with transient fever

W. C. Miller-Hance and A. Vegas

d. Evaluating a patient with atrial flutter when anticoagulation is planned and cardioversion is being deferred e. Yearly evaluation of pulmonary regurgitation in an obese patient after tetralogy of Fallot repair Answer: a Explanation: Among non perioperative indications, evaluating suspected intracardiac thrombus when TTE is nondiagnostic in the adult patient  represents one of the most frequent indications for the use of the technology. Although TEE might be appropriate in certain adult patients with the other conditions listed, these in general represent less likely indications.  3. All of the following statements with respect to three-­ dimensional TEE imaging are true EXCEPT a. Using the technology requires additional expertise over 2D imaging b. Probes capable of 3D imaging incorporate all features available in 2D imaging devices c. 3D should replace 2D imaging in evaluating complex congenital heart disease d. 3D TEE can be used to assess LV volume e. Measurements of LV volume are load dependent Answer: c Explanation: 3D imaging should complement, rather than replace, 2D imaging in the assessment of CHD. 4. Which of the following statements best describes the intraoperative TEE assessment of LV function a. Current technology allows expeditious quantitative evaluation b. Fractional area change can be equated to EF c. 2D measurements of EF have the same accuracy and reproducibility as 3D methods d. Ejection fraction implies a volume measurement e. M-mode assessment of LV indices is as accurate as 2D and 3D echocardiography Answer: d Explanation: Ejection fraction determinations rely on volumetric assessments. Although FAC serves as a method to estimate LV function, the parameter is derived from measurements of area, not volume, unlike EF. Current technology for the quantitative evaluation of LV systolic function is time-­consuming; thus, in the intraoperative setting, functional assessment tends to be qualitative. In patients with CHD, 3D echocardiography provides better accuracy and reproducibility than 2D methods in measuring LV volume and function. M-mode is currently rarely use in the intraop-

18  Intraoperative and Postoperative Applications

601

10. Ungerleider RM, Greeley WJ, Sheikh KH, et al. Routine use of intraoperative epicardial echocardiography and Doppler color flow imaging to guide and evaluate repair of congenital heart lesions. A prospective study. J Thorac Cardiovasc Surg. 1990;100:297–309. 5. Useful applications of TEE in perioperative management 11. Ungerleider R. Decision making in pediatric cardiac surgery using intraoperative echo. Int J Card Imaging. 1989;4:33–5. include 12. Hsu YH, Santulli T, Wong AL, Drinkwater D, Laks H, Williams a. Ensuring cardiac deairing before the aortic cross-­ RG.  Impact of intraoperative echocardiography on surgiclamp is removed cal management of congenital heart disease. Am J Cardiol. 1991;67:1279–83. b. Confirming the preoperative diagnosis 13. Ungerleider RM.  The use of intraoperative epicardial echocar c. Selecting appropriate inotropes and vasoactive drugs diography with color flow imaging during the repair of complete d. Excluding residual hemodynamically significant intraatrioventricular septal defects. Cardiol Young. 1992;2:56–64. cardiac shunts 14. Papagiannis J, Kanter RJ, Armstrong BE, Greeley WJ, Ungerleider RM. Intraoperative epicardial echocardiography during repair of e. All of the above tetralogy of Fallot. J Am Soc Echocardiogr. 1993;6:366–73. 15. Frazin L, Talano JV, Stephanides L, Loeb HS, Kopel L, Gunnar Answer: e RM. Esophageal echocardiography. Circulation. 1976;54:102–8. Explanation: TEE has been shown to be beneficial in all 16. Matsumoto M, Oka Y, Strom J, et al. Application of transesophageal echocardiography to continuous intraoperative monitoring of listed applications. left ventricular performance. Am J Cardiol. 1980;46:95–105. 17. Hisanaga K, Hisanaga A, Nagata K, Ichie Y.  Transesophageal Acknowledgments  The authors would like to gratefully acknowledge cross-sectional echocardiography. Am Heart J. 1980;100:605–9. Isobel A. Russell, MD for her expertise and contribution to this chapter 18. Hanrath P, Kremer P, Langenstein BA, Matsumoto M, Bleifeld and co-authorship in the prior edition. W. [Transesophageal echocardiography. A new method for dynamic ventricle function analysis]. Dtsch Med Wochenschr 1981;106:523–525. 19. Kyo S, Takamoto S, Matsumura M, et  al. Immediate and early References postoperative evaluation of results of cardiac surgery by transesophageal two-dimensional Doppler echocardiography. Circulation. 1987;76:V113–21. 1. Gussenhoven EJ, van Herwerden LA, Roelandt J, Ligtvoet KM, Bos E, Witsenburg M.  Intraoperative two-dimensional echo- 20. Cyran SE, Kimball TR, Meyer RA, et al. Efficacy of intraoperative transesophageal echocardiography in children with congenital cardiography in congenital heart disease. J Am Coll Cardiol. heart disease. Am J Cardiol. 1989;63:594–8. 1987;9:565–72. 2. Hahn RT, Abraham T, Adams MS, et al. Guidelines for performing 21. Kyo S, Koike K, Takanawa E, et  al. Impact of transesophageal Doppler echocardiography on pediatric cardiac surgery. Int J Card a comprehensive transesophageal echocardiographic examination: Imaging. 1989;4:41–2. recommendations from the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. J Am Soc 22. Ritter SB, Thys D.  Pediatric transesophageal color flow imaging: smaller probes for smaller hearts. Echocardiography. Echocardiogr. 2013;26:921–64. 1989;6:431–40. 3. Puchalski MD, Lui GK, Miller-Hance WC, et  al. Guidelines for performing a comprehensive transesophageal echocardio- 23. Ritter SB, Hillel Z, Narang J, Lewis D, Thys D. Transesophageal real-time Doppler flow imaging in congenital heart disease: expegraphic examination in children and all patients with congenital rience with a new pediatric transducer probe. Dyn Cardiovasc heart disease: recommendations from the American Society of Imaging. 1989;2:92–6. Echocardiography. J Am Soc Echocardiogr. 2019;32:173–215. 4. Simpson J, Lopez L, Acar P, et al. Three-dimensional echocardiog- 24. Ritter SB.  Transesophageal echocardiography in children: new peephole to the heart. J Am Coll Cardiol. 1990;16:447–50. raphy in congenital heart disease: an expert consensus document from the European Association of Cardiovascular Imaging and the 25. Ritter SB. Pediatric transesophageal color flow imaging 1990: the long and short of it. Echocardiography. 1990;7:713–25. American Society of Echocardiography. J Am Soc Echocardiogr. 26. Stümper OF, Elzenga NJ, Hess J, Sutherland GR. Transesophageal 2017;30:1–27. echocardiography in children with congenital heart disease: an 5. Mitchell C, Rahko PS, Blauwet LA, et al. Guidelines for performinitial experience. J Am Coll Cardiol. 1990;16:433–41. ing a comprehensive transthoracic echocardiographic examination in adults: recommendations from the American Society of 27. Ritter SB. Transesophageal real-time echocardiography in infants and children with congenital heart disease. J Am Coll Cardiol. Echocardiography. J Am Soc Echocardiogr. 2019;32:1–64. 1991;18:569–80. 6. Ozturk E, Cansaran Tanidir I, Ayyildiz P, et al. The role of intraoperative epicardial echocardiography in pediatric cardiac surgery. 28. Roberson DA, Muhiudeen IA, Silverman NH.  Transesophageal echocardiography in pediatrics: technique and limitations. Echocardiography. 2018;35:999–1004. Echocardiography. 1990;7:699–712. 7. Johnson ML, Holmes JH, Spangler RD, Paton BC. Usefulness of echocardiography in patients undergoing mitral valve surgery. J 29. Muhiudeen IA, Roberson DA, Silverman NH, Haas G, Turley K, Cahalan MK.  Intraoperative echocardiography in infants and Thorac Cardiovasc Surg. 1972;64:922–34. children with congenital cardiac shunt lesions: ­transesophageal 8. Spotnitz HM.  Two-dimensional ultrasound and cardiac operaversus epicardial echocardiography. J Am Coll Cardiol. tions. J Thorac Cardiovasc Surg. 1982;83:43–51. 1990;16:1687–95. 9. Ungerleider RM, Kisslo JA, Greeley WJ, Van Trigt P, Sabiston DC. Intraoperative prebypass and postbypass epicardial color flow 30. Stümper O, Kaulitz R, Sreeram N, et al. Intraoperative transesophageal versus epicardial ultrasound in surgery for congenital heart imaging in the repair of atrioventricular septal defects. J Thorac disease. J Am Soc Echocardiogr. 1990;3:392–401. Cardiovasc Surg. 1989;98:90–9.

erative setting and is the least accurate and reproducible technique compared with 2D and 3D imaging.

602 31. Sreeram N, Stümper OF, Kaulitz R, Hess J, Roelandt JR, Sutherland GR.  Comparative value of transthoracic and transesophageal echocardiography in the assessment of congenital abnormalities of the atrioventricular junction. J Am Coll Cardiol. 1990;16:1205–14. 32. Roberson DA, Muhiudeen IA, Cahalan MK, Silverman NH, Haas G, Turley K. Intraoperative transesophageal echocardiography of ventricular septal defect. Echocardiography. 1991;8:687–97. 33. Roberson DA, Muhiudeen IA, Silverman NH, Turley K, Haas GS, Cahalan MK. Intraoperative transesophageal echocardiography of atrioventricular septal defect. J Am Coll Cardiol. 1991;18:537–45. 34. Wienecke M, Fyfe DA, Kline CH, et al. Comparison of intraoperative transesophageal echocardiography to epicardial imaging in children undergoing ventricular septal defect repair. J Am Soc Echocardiogr. 1991;4:607–14. 35. Muhiudeen IA, Roberson DA, Silverman NH, Haas GS, Turley K, Cahalan MK.  Intraoperative echocardiography for evaluation of congenital heart defects in infants and children. Anesthesiology. 1992;76:165–72. 36. Muhiudeen I, Silverman N.  Intraoperative transesophageal echocardiography using high resolution imaging in infants and children with congenital heart disease. Echocardiography. 1993;10:599–608. 37. Omoto R, Kyo S, Matsumura M, et al. Bi-plane color transesophageal Doppler echocardiography (color TEE): its advantages and limitations. Int J Card Imaging. 1989;4:57–8. 38. Seward JB, Khandheria BK, Edwards WD, Oh JK, Freeman WK, Tajik AJ.  Biplanar transesophageal echocardiography: anatomic correlations, image orientation, and clinical applications. Mayo Clin Proc. 1990;65:1193–213. 39. Gentles TL, Rosenfeld HM, Sanders SP, Laussen PC, Burke RP, van der Velde ME. Pediatric biplane transesophageal echocardiography: preliminary experience. Am Heart J. 1994;128:1225–33. 40. Lam J, Neirotti RA, Lubbers WJ, et al. Usefulness of biplane transesophageal echocardiography in neonates, infants and children with congenital heart disease. Am J Cardiol. 1993;72:699–706. 41. O’Leary PW, Hagler DJ, Seward JB, et al. Biplane intraoperative transesophageal echocardiography in congenital heart disease. Mayo Clin Proc. 1995;70:317–26. 42. Xu J, Shiota T, Ge S, et al. Intraoperative transesophageal echocardiography using high-resolution biplane 7.5 MHz probes with continuous-wave Doppler capability in infants and children with tetralogy of Fallot. Am J Cardiol. 1996;77:539–42. 43. Hoffman P, Stümper O, Rydelwska-Sadowska W, Sutherland GR. Transgastric imaging: a valuable addition to the assessment of congenital heart disease by transverse plane transesophageal echocardiography. J Am Soc Echocardiogr. 1993;6:35–44. 44. Muhiudeen IA, Silverman NH, Anderson RH.  Transesophageal transgastric echocardiography in infants and children: the subcostal view equivalent. J Am Soc Echocardiogr. 1995;8:231–44. 45. Flachskampf FA, Hoffmann R, Verlande M, Schneider W, Ameling W, Hanrath P. Initial experience with a multiplane transoesophageal echo-transducer: assessment of diagnostic potential. Eur Heart J. 1992;13:1201–6. 46. Roelandt JR, Thomson IR, Vletter WB, Brommersma P, Bom N, Linker DT.  Multiplane transesophageal echocardiography: latest evolution in an imaging revolution. J Am Soc Echocardiogr. 1992;5:361–7. 47. Seward JB, Khandheria BK, Freeman WK, et al. Multiplane transesophageal echocardiography: image orientation, examination technique, anatomic correlations, and clinical applications. Mayo Clin Proc. 1993;68:523–51. 48. Tardif JC, Schwartz SL, Vannan MA, Cao QL, Pandian NG.  Clinical usefulness of multiplane transesophageal echocardiography: comparison to biplanar imaging. Am Heart J. 1994;128:156–66.

W. C. Miller-Hance and A. Vegas 49. Yvorchuk KY, Sochowski RA, Chan KL. A prospective comparison of the multiplane probe with the biplane probe in structure visualization and Doppler examination during transesophageal echocardiography. J Am Soc Echocardiogr. 1995;8:111–20. 50. Cromme-Dijkhuis AH, Djoa KK, Bom N, Hess J. Pediatric transesophageal echocardiography by means of a miniature 5-MHz multiplane transducer. Echocardiography. 1996;13:685–9. 51. Djoa KK, De Jong N, Cromme-Dijkhuis AH, Lancée CT, Bom N.  Two decades of transesophageal phased array probes. Ultrasound Med Biol. 1996;22:1–9. 52. Sloth E, Hasenkam JM, Sørensen KE, et  al. Pediatric multiplane transesophageal echocardiography in congenital heart disease: new possibilities with a miniaturized probe. J Am Soc Echocardiogr. 1996;9:622–8. 53. Lam J, Neirotti RA, Hardjowijono R, Blom-Muilwijk CM, Schuller JL, Visser CA.  Transesophageal echocardiography with the use of a four-millimeter probe. J Am Soc Echocardiogr. 1997;10:499–504. 54. Shiota T, Lewandowski R, Piel JE, et al. Micromultiplane transesophageal echocardiographic probe for intraoperative study of congenital heart disease repair in neonates, infants, children, and adults. Am J Cardiol. 1999;83:292–5. 55. Rice MJ, Sahn DJ.  Transesophageal echocardiography for congenital heart disease--who, what, and when. Mayo Clin Proc. 1995;70:401–2. 56. Scohy TV, Gommers D, Jan ten Harkel AD, Deryck Y, McGhie J, Bogers AJ. Intraoperative evaluation of micromultiplane transesophageal echocardiographic probe in surgery for congenital heart disease. Eur J Echocardiogr. 2007;8:241–6. 57. Zyblewski SC, Shirali GS, Forbus GA, et  al. Initial experience with a miniaturized multiplane transesophageal probe in small infants undergoing cardiac operations. Ann Thorac Surg. 2010;89:1990–4. 58. Pushparajah K, Miller OI, Rawlins D, Barlow A, Nugent K, Simpson JM.  Clinical application of a micro multiplane transoesophageal probe in congenital cardiac disease. Cardiol Young. 2012;22:170–7. 59. Bruce CJ, O’Leary P, Hagler DJ, Seward JB, Cabalka AK. Miniaturized transesophageal echocardiography in newborn infants. J Am Soc Echocardiogr. 2002;15:791–7. 60. Ferns S, Komarlu R, Van Bergen A, Multani K, Cui VW, Roberson DA.  Transesophageal echocardiography in critically ill acute postoperative infants: comparison of AcuNav intracardiac echocardiographic and microTEE miniaturized transducers. J Am Soc Echocardiogr. 2012;25:874–81. 61. Sugeng L, Shernan SK, Salgo IS, et al. Live 3-dimensional transesophageal echocardiography initial experience using the fully-­ sampled matrix array probe. J Am Coll Cardiol. 2008;52:446–9. 62. Vegas A, Meineri M. Core review: three-dimensional transesophageal echocardiography is a major advance for intraoperative clinical management of patients undergoing cardiac surgery: a core review. Anesth Analg. 2010;110:1548–73. 63. Lang RM, Badano LP, Tsang W, et  al. EAE/ASE recommendations for image acquisition and display using three-dimensional echocardiography. J Am Soc Echocardiogr. 2012;25:3–46. 64. Simpson J, Miller O, Bell A, Bellsham-Revell H, McGhie J, Meijboom F.  Image orientation for three-dimensional echocardiography of congenital heart disease. Int J Cardiovasc Imaging. 2012;28:743–53. 65. Faletra FF, Nucifora G, Ho SY.  Real-time 3-dimensional transesophageal echocardiography of the atrioventricular septal defect. Circ Cardiovasc Imaging. 2011;4:e7–9. 66. Cossor W, Cui VW, Roberson DA.  Three-dimensional echocardiographic en face views of ventricular septal defects: feasibility, accuracy, imaging protocols and reference image collection. J Am Soc Echocardiogr. 2015;28:1020–9.

18  Intraoperative and Postoperative Applications 67. Silvestry FE, Cohen MS, Armsby LB, et  al. Guidelines for the echocardiographic assessment of atrial septal defect and patent foramen ovale: from the American Society of Echocardiography and Society for Cardiac Angiography and Interventions. J Am Soc Echocardiogr. 2015;28:910–58. 68. Lang RM, Badano LP, Mor-Avi V, et  al. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015;28:1–39.e14. 69. Zoghbi WA, Adams D, Bonow RO, et al. Recommendations for noninvasive evaluation of native valvular regurgitation: a report from the American Society of Echocardiography developed in collaboration with the Society for Cardiovascular Magnetic Resonance. J Am Soc Echocardiogr. 2017;30:303–71. 70. Toole BJ, Slesnick TC, Kreeger J, et  al. The miniaturized multiplane micro-transesophageal echocardiographic probe: a comparative evaluation of its accuracy and image quality. J Am Soc Echocardiogr. 2015;28:802–7. 71. Miller-Hance WC, Silverman NH. Transesophageal echocardiography (TEE) in congenital heart disease with focus on the adult. Cardiol Clin. 2000;18:861–92. 72. Russell IA, Rouine-Rapp K, Stratmann G, Miller-Hance WC. Congenital heart disease in the adult: a review with internet-­ accessible transesophageal echocardiographic images. Anesth Analg. 2006;102:694–723. 73. Kamra K, Russell I, Miller-Hance WC. Role of transesophageal echocardiography in the management of pediatric patients with congenital heart disease. Paediatr Anaesth. 2011;21:479–93. 74. Stümper O, Fraser AG, Elzenga N, et al. Assessment of ventricular septal defect closure by intraoperative epicardial ultrasound. J Am Coll Cardiol. 1990;16:1672–9. 75. Fyfe DA, Kline CH, Sade RM, Greene CA, Gillette PC. The utility of transesophageal echocardiography during and after Fontan operations in small children. Am Heart J. 1991;122:1403–15. 76. Fyfe DA, Kline CH. Transesophageal echocardiography for congenital heart disease. Echocardiography. 1991;8:573–86. 77. Lam J, Neirotti RA, Nijveld A, Schuller JL, Blom-Muilwijk CM, Visser CA.  Transesophageal echocardiography in pediatric patients: preliminary results. J Am Soc Echocardiogr. 1991;4:43–50. 78. Stumper O. Transesophageal echocardiography: a new diagnostic method in paediatric cardiology. Arch Dis Child. 1991;66:1175–7. 79. Stümper O, Kaulitz R, Elzenga NJ, et al. The value of transesophageal echocardiography in children with congenital heart disease. J Am Soc Echocardiogr. 1991;4:164–76. 80. Tee SD, Shiota T, Weintraub R, et  al. Evaluation of ventricular septal defect by transesophageal echocardiography: intraoperative assessment. Am Heart J. 1994;127:585–92. 81. Shuler CO, Fyfe DA, Sade R, Crawford FA.  Transesophageal echocardiographic evaluation of cor triatriatum in children. Am Heart J. 1995;129:507–10. 82. Stevenson JG.  Role of intraoperative transesophageal echocardiography during repair of congenital cardiac defects. Acta Paediatr Suppl. 1995;410:23–33. 83. Bezold LI, Pignatelli R, Altman CA, et  al. Intraoperative transesophageal echocardiography in congenital heart surgery. The Texas Children’s Hospital experience. Tex Heart Inst J. 1996;23:108–15. 84. Bengur AR, Li JS, Herlong JR, Jaggers J, Sanders SP, Ungerleider RM.  Intraoperative transesophageal echocardiography in congenital heart disease. Semin Thorac Cardiovasc Surg. 1998;10: 255–64. 85. Kavanaugh-McHugh A, Tobias JD, Doyle T, Heitmiller ES, Meagher C. Transesophageal echocardiography in pediatric congenital heart disease. Cardiol Rev. 2000;8:288–306.

603 86. Lim DS, Dent JM, Gutgesell HP, Matherne GP, Kron IL.  Transesophageal echocardiographic guidance for surgical repair of aortic insufficiency in congenital heart disease. J Am Soc Echocardiogr. 2007;20:1080–5. 87. Ungerleider RM, Kisslo JA, Greeley WJ, et  al. Intraoperative echocardiography during congenital heart operations: experience from 1,000 cases. Ann Thorac Surg. 1995;60:S539–42. 88. Sloth E, Pedersen J, Olsen KH, Wanscher M, Hansen OK, Sørensen KE.  Transoesophageal echocardiographic monitoring during paediatric cardiac surgery: obtainable information and feasibility in 532 children. Paediatr Anaesth. 2001;11:657–62. 89. Randolph GR, Hagler DJ, Connolly HM, et  al. Intraoperative transesophageal echocardiography during surgery for congenital heart defects. J Thorac Cardiovasc Surg. 2002;124:1176–82. 90. Yumoto M, Katsuya H.  Transesophageal echocardiography for cardiac surgery in children. J Cardiothorac Vasc Anesth. 2002;16:587–91. 91. Bettex DA, Schmidlin D, Bernath MA, et  al. Intraoperative transesophageal echocardiography in pediatric congenital cardiac surgery: a two-center observational study. Anesth Analg. 2003;97:1275–82. 92. Ma XJ, Huang GY, Liang XC, et al. Transoesophageal echocardiography in monitoring, guiding, and evaluating surgical repair of congenital cardiac malformations in children. Cardiol Young. 2007;17:301–6. 93. Guzeltas A, Ozyilmaz I, Tanidir C, et al. The significance of transesophageal echocardiography in assessing congenital heart disease: our experience. Congenit Heart Dis. 2014;9:300–6. 94. Jijeh AM, Omran AS, Najm HK, Abu-Sulaiman RM.  Role of intraoperative transesophageal echocardiography in pediatric cardiac surgery. J Saudi Heart Assoc. 2016;28:89–94. 95. Stevenson JG, Sorensen GK, Gartman DM, Hall DG, Rittenhouse EA. Transesophageal echocardiography during repair of congenital cardiac defects: identification of residual problems necessitating reoperation. J Am Soc Echocardiogr. 1993;6:356–65. 96. Komai H, Naito Y, Fujiwara K, Uemura S. The benefits of surgical atrial septostomy guided by transesophageal echocardiography in pediatric patients. J Thorac Cardiovasc Surg. 1999;118:758–9. 97. Kawahito S, Kitahata H, Tanaka K, et al. Intraoperative management of a pediatric patient undergoing cardiac tumor resection with the aid of transesophageal and epicardial echocardiography. Anesth Analg. 1999;88:1048–50. 98. Kawahito S, Kitahata H, Tanaka K, Nozaki J, Oshita S. Intraoperative evaluation of pulmonary artery flow during the Fontan procedure by transesophageal Doppler echocardiography. Anesth Analg. 2000;91:1375–80. 99. Chen TH, Chan KC, Cheng YJ, Wang MJ, Tsai SK.  Bedside pericardiocentesis under the guidance of transesophageal echocardiography in a 13-month-old boy. J Formos Med Assoc. 2001;100:620–2. 100. Boddu K, Vavilala MS, Stevenson JG, Lam AM. The use of transesophageal echocardiography to facilitate removal of a thoracic nail. Anesth Analg. 2002;95:624–6. 101. Nitta K, Kawahito S, Kitahata H, Nozaki J, Katayama T, Oshita S.  Two unusual complications associated with cardiopulmonary bypass for pediatric cardiac surgery detected by transesophageal echocardiography after decannulation. Paediatr Anaesth. 2008;18:325–9. 102. Lavoie J, Burrows FA, Gentles TL, Sanders SP, Burke RP, Javorski JJ.  Transoesophageal echocardiography detects residual ductal flow during video-assisted thoracoscopic patent ductus arteriosus interruption. Can J Anaesth. 1994;41:310–3. 103. Lavoie J, Javorski JJ, Donahue K, Sanders SP, Burke RP, Burrows FA. Detection of residual flow by transesophageal echocardiography during video-assisted thoracoscopic patent ductus arteriosus interruption. Anesth Analg. 1995;80:1071–5.

604 104. Ho AC, Tan PP, Yang MW, et al. The use of multiplane transesophageal echocardiography to evaluate residual patent ductus arteriosus during video-assisted thoracoscopy in adults. Surg Endosc. 1999;13:975–9. 105. Ho AC, Chen CK, Yang MW, Chu JJ, Lin PJ. Usefulness of intraoperative transesophageal echocardiography in the assessment of surgical repair of pediatric ventricular septal defects with video-­ assisted endoscopic techniques in children. Chang Gung Med J. 2004;27:646–53. 106. Bacha EA, Cao QL, Galantowicz ME, et al. Multicenter experience with perventricular device closure of muscular ventricular septal defects. Pediatr Cardiol. 2005;26:169–75. 107. Gan C, An Q, Lin K, et al. Perventricular device closure of ventricular septal defects: six months results in 30 young children. Ann Thorac Surg. 2008;86:142–6. 108. Fyfe DA, Ritter SB, Snider AR, et al. Guidelines for transesophageal echocardiography in children. J Am Soc Echocardiogr. 1992;5:640–4. 109. Practice guidelines for perioperative transesophageal echocardiography. A report by the American Society of Anesthesiologists and the Society of Cardiovascular Anesthesiologists Task Force on Transesophageal Echocardiography. Anesthesiology. 1996;84:986–1006. 110. Cheitlin MD, Alpert JS, Armstrong WF, et al. ACC/AHA guidelines for the clinical application of echocardiography. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Clinical Application of Echocardiography). Developed in collaboration with the American Society of Echocardiography. Circulation. 1997;95:1686–744. 111. Cheitlin MD, Armstrong WF, Aurigemma GP, et al. ACC/AHA/ ASE 2003 Guideline update for the clinical application of echocardiography: summary article: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASE Committee to Update the 1997 Guidelines for the Clinical Application of Echocardiography). Circulation. 2003;108:1146–62. 112. Stevenson JG. Utilization of intraoperative transesophageal echocardiography during repair of congenital cardiac defects: a survey of North American centers. Clin Cardiol. 2003;26:132–4. 113. Ayres NA, Miller-Hance W, Fyfe DA, et al. Indications and guidelines for performance of transesophageal echocardiography in the patient with pediatric acquired or congenital heart disease: report from the task force of the Pediatric Council of the American Society of Echocardiography. J Am Soc Echocardiogr. 2005;18:91–8. 114. American Society of Anesthesiologists and Society of Cardiovascular Anesthesiologists Task Force on Transesophageal Echocardiography. Practice guidelines for perioperative transesophageal echocardiography. An updated report by the American Society of Anesthesiologists and the Society of Cardiovascular Anesthesiologists Task Force on Transesophageal Echocardiography. Anesthesiology. 2010;112:1084–96. 115. Sawchuk C, Fayad A.  Confirmation of internal jugular guide wire position utilizing transesophageal echocardiography. Can J Anaesth. 2001;48:688–90. 116. Mahmood F, Sundar S, Khabbaz K. Misplacement of a guidewire diagnosed by transesophageal echocardiography. J Cardiothorac Vasc Anesth. 2007;21:420–1. 117. Andropoulos DB. Transesophageal echocardiography as a guide to central venous catheter placement in pediatric patients undergoing cardiac surgery. J Cardiothorac Vasc Anesth. 1999;13:320–1. 118. Chaney MA, Minhaj MM, Patel K, Muzic D. Transoesophageal echocardiography and central line insertion. Ann Card Anaesth. 2007;10:127–31. 119. Hsu JH, Wang CK, Hung CW, Wang SS, Cheng KI, Wu JR.  Transesophageal echocardiography and laryngeal mask air-

W. C. Miller-Hance and A. Vegas way for placement of permanent central venous catheter in cancer patients with radiographically unidentifiable SVC-RA junction: effectiveness and safety. Kaohsiung J Med Sci. 2007;23:435–41. 120. Andropoulos DB, Stayer SA, Bent ST, et al. A controlled study of transesophageal echocardiography to guide central venous catheter placement in congenital heart surgery patients. Anesth Analg. 1999;89:65–70. 121. Gold JP, Jonas RA, Lang P, Elixson EM, Mayer JE, Castaneda AR.  Transthoracic intracardiac monitoring lines in pediatric surgical patients: a ten-year experience. Ann Thorac Surg. 1986;42:185–91. 122. Flori HR, Johnson LD, Hanley FL, Fineman JR.  Transthoracic intracardiac catheters in pediatric patients recovering from congenital heart defect surgery: associated complications and outcomes. Crit Care Med. 2000;28:2997–3001. 123. Rimensberger PC, Beghetti M. Pulmonary artery catheter placement under transoesophageal echocardiography guidance. Paediatr Anaesth. 1999;9:167–70. 124. Eguchi S, Bosher LH.  Myocardial dysfunction resulting from coronary air embolism. Surgery. 1962;51:103–11. 125. Goldfarb D, Bahnson H. Early and late effects on the heart of small amounts of air in the coronary circulation. J Thorac Cardiovasc Surg. 1963;46:368–78. 126. Borger MA, Peniston CM, Weisel RD, Vasiliou M, Green RE, Feindel CM. Neuropsychologic impairment after coronary bypass surgery: effect of gaseous microemboli during perfusionist interventions. J Thorac Cardiovasc Surg. 2001;121:743–9. 127. Fearn SJ, Pole R, Burgess M, Ray SG, Hooper TL, McCollum CN.  Cerebral embolisation during modern cardiopulmonary bypass. Eur J Cardiothorac Surg. 2001;20:1163–7. 128. Duff HJ, Buda AJ, Kramer R, Strauss HD, David TE, Berman ND.  Detection of entrapped intracardiac air with intraoperative echocardiography. Am J Cardiol. 1980;46:255–60. 129. Oka Y, Moriwaki KM, Hong Y, et al. Detection of air emboli in the left heart by M-mode transesophageal echocardiography following cardiopulmonary bypass. Anesthesiology. 1985;63:109–13. 130. Topol EJ, Humphrey LS, Borkon AM, et al. Value of intraoperative left ventricular microbubbles detected by transesophageal two-dimensional echocardiography in predicting neurologic outcome after cardiac operations. Am J Cardiol. 1985;56:773–5. 131. Diehl JT, Ramos D, Dougherty F, Pandian NG, Payne DD, Cleveland RJ. Intraoperative, two-dimensional echocardiography-­ guided removal of retained intracardiac air. Ann Thorac Surg. 1987;43:674–5. 132. Meloni L, Abbruzzese PA, Cardu G, et al. Detection of microbubbles released by oxygenators during cardiopulmonary bypass by intraoperative transesophageal echocardiography. Am J Cardiol. 1990;66:511–4. 133. Orihashi K, Matsuura Y, Hamanaka Y, et al. Retained intracardiac air in open heart operations examined by transesophageal echocardiography. Ann Thorac Surg. 1993;55:1467–71. 134. Dalmas JP, Eker A, Girard C, et  al. Intracardiac air clearing in valvular surgery guided by transesophageal echocardiography. J Heart Valve Dis. 1996;5:553–7. 135. Orihashi K, Matsuura Y, Sueda T, Shikata H, Mitsui N, Sueshiro M. Pooled air in open heart operations examined by transesophageal echocardiography. Ann Thorac Surg. 1996;61:1377–80. 136. Hoka S, Okamoto H, Yamaura K, Takahashi S, Tominaga R, Yasui H.  Removal of retained air during cardiac surgery with transesophageal echocardiography and capnography. J Clin Anesth. 1997;9:457–61. 137. Greeley WJ, Kern FH, Ungerleider RM, Kisslo JA. Intramyocardial air causes right ventricular dysfunction after repair of a congenital heart defect. Anesthesiology. 1990;73:1042–6. 138. Cassorla L, Miller-Hance WC, Rouine-Rapp K, Reddy VM, Hanley FL, Silverman NH. Reliability of intraoperative contrast

18  Intraoperative and Postoperative Applications transesophageal echocardiography for detecting interatrial communications in patients with other congenital cardiovascular malformations. Am J Cardiol. 2003;91:1027–31. 139. Tousignant CP, Walsh F, Mazer CD. The use of transesophageal echocardiography for preload assessment in critically ill patients. Anesth Analg. 2000;90:351–5. 140. Buhre W, Buhre K, Kazmaier S, Sonntag H, Weyland A. Assessment of cardiac preload by indicator dilution and transoesophageal echocardiography. Eur J Anaesthesiol. 2001;18:662–7. 141. Stoddard MF, Longaker RA, Calzada N. Left atrial inflow propagation rate: a new transesophageal echocardiographic index of preload. J Am Soc Echocardiogr. 2002;15:1057–64. 142. Cheung AT, Savino JS, Weiss SJ, Aukburg SJ, Berlin JA.  Echocardiographic and hemodynamic indexes of left ventricular preload in patients with normal and abnormal ventricular function. Anesthesiology. 1994;81:376–87. 143. Swenson JD, Harkin C, Pace NL, Astle K, Bailey P. Transesophageal echocardiography: an objective tool in defining maximum ventricular response to intravenous fluid therapy. Anesth Analg. 1996;83:1149–53. 144. Hofer CK, Ganter MT, Rist A, Klaghofer R, Matter-Ensner S, Zollinger A. The accuracy of preload assessment by different transesophageal echocardiographic techniques in patients undergoing cardiac surgery. J Cardiothorac Vasc Anesth. 2008;22:236–42. 145. Bu L, Munns S, Zhang H, et al. Rapid full volume data acquisition by real-time 3-dimensional echocardiography for assessment of left ventricular indexes in children: a validation study compared with magnetic resonance imaging. J Am Soc Echocardiogr. 2005;18:299–305. 146. Lu X, Xie M, Tomberlin D, et al. How accurately, reproducibly, and efficiently can we measure left ventricular indices using M-mode, 2-dimensional, and 3-dimensional echocardiography in children. Am Heart J. 2008;155:946–53. 147. Balluz R, Liu L, Zhou X, Ge S. Real-time three-dimensional echocardiography for quantification of ventricular volumes, mass, and function in children with congenital and acquired heart diseases. Echocardiography. 2013;30:472–82. 148. Altmann K, Shen Z, Boxt LM, et  al. Comparison of three-­ dimensional echocardiographic assessment of volume, mass, and function in children with functionally single left ventricles with two-dimensional echocardiography and magnetic resonance imaging. Am J Cardiol. 1997;80:1060–5. 149. van den Bosch AE, Robbers-Visser D, Krenning BJ, et al. Real-­ time transthoracic three-dimensional echocardiographic assessment of left ventricular volume and ejection fraction in congenital heart disease. J Am Soc Echocardiogr. 2006;19:1–6. 150. Riehle TJ, Mahle WT, Parks WJ, Sallee D, Fyfe DA.  Real-time three-dimensional echocardiographic acquisition and quantification of left ventricular indices in children and young adults with congenital heart disease: comparison with magnetic resonance imaging. J Am Soc Echocardiogr. 2008;21:78–83. 151. Grossgasteiger M, Hien MD, Graser B, et al. Assessment of left ventricular size and function during cardiac surgery. An intraoperative evaluation of six two-dimensional echocardiographic methods with real-time three-dimensional echocardiography as a reference. Echocardiography. 2013;30:672–81. 152. Meris A, Santambrogio L, Casso G, Mauri R, Engeler A, Cassina T.  Intraoperative three-dimensional versus two-dimensional echocardiography for left ventricular assessment. Anesth Analg. 2014;118:711–20. 153. Smith MD, MacPhail B, Harrison MR, Lenhoff SJ, DeMaria AN.  Value and limitations of transesophageal echocardiography in determination of left ventricular volumes and ejection fraction. J Am Coll Cardiol. 1992;19:1213–22. 154. Laser KT, Bunge M, Hauffe P, et  al. Left ventricular volumetry in healthy children and adolescents: comparison of two different

605 real-time three-dimensional matrix transducers with cardiovascular magnetic resonance. Eur J Echocardiogr. 2010;11:138–48. 155. Shimada YJ, Shiota T. A meta-analysis and investigation for the source of bias of left ventricular volumes and function by three-­ dimensional echocardiography in comparison with magnetic resonance imaging. Am J Cardiol. 2011;107:126–38. 156. Swenson JD, Bull D, Stringham J. Subjective assessment of left ventricular preload using transesophageal echocardiography: corresponding pulmonary artery occlusion pressures. J Cardiothorac Vasc Anesth. 2001;15:580–3. 157. Reich DL, Konstadt SN, Nejat M, Abrams HP, Bucek J. Intraoperative transesophageal echocardiography for the detection of cardiac preload changes induced by transfusion and phlebotomy in pediatric patients. Anesthesiology. 1993;79:10–5. 158. Poortmans G, Schüpfer G, Roosens C, Poelaert J. Transesophageal echocardiographic evaluation of left ventricular function. J Cardiothorac Vasc Anesth. 2000;14:588–98. 159. Lopez L, Colan SD, Frommelt PC, et  al. Recommendations for quantification methods during the performance of a pediatric echocardiogram: a report from the Pediatric Measurements Writing Group of the American Society of Echocardiography Pediatric and Congenital Heart Disease Council. J Am Soc Echocardiogr. 2010;23:465–95. 160. Tei C. New non-invasive index for combined systolic and diastolic ventricular function. J Cardiol. 1995;26:135–6. 161. Eidem BW, Tei C, O’Leary PW, Cetta F, Seward JB. Nongeometric quantitative assessment of right and left ventricular function: myocardial performance index in normal children and patients with Ebstein anomaly. J Am Soc Echocardiogr. 1998;11:849–56. 162. Eidem BW, O’Leary PW, Tei C, Seward JB.  Usefulness of the myocardial performance index for assessing right ventricular function in congenital heart disease. Am J Cardiol. 2000;86:654–8. 163. Roberson DA, Cui W.  Right ventricular Tei index in children: effect of method, age, body surface area, and heart rate. J Am Soc Echocardiogr. 2007;20:764–70. 164. Ikemba CM, Su JT, Stayer SA, et  al. Myocardial performance index with sevoflurane-pancuronium versus fentanyl-midazolam-­ pancuronium in infants with a functional single ventricle. Anesthesiology. 2004;101:1298–305. 165. Fernandes JMG, de Oliveira RB, Rivera IR, et al. Clinical value of myocardial performance index in patients with isolated diastolic dysfunction. Cardiovasc Ultrasound. 2019;17:17. 166. Moller JE, Poulsen SH, Egstrup K.  Effect of preload alternations on a new Doppler echocardiographic index of combined systolic and diastolic performance. J Am Soc Echocardiogr. 1999;12:1065–72. 167. Davlouros PA, Niwa K, Webb G, Gatzoulis MA. The right ventricle in congenital heart disease. Heart. 2006;92(Suppl 1):i27–38. 168. Roche SL, Redington AN. The failing right ventricle in congenital heart disease. Can J Cardiol. 2013;29:768–78. 169. Friedberg MK, Reddy S.  Right ventricular failure in congenital heart disease. Curr Opin Pediatr. 2019;5:604–10. 170. Brida M, Diller GP, Gatzoulis MA.  Systemic right ventricle in adults with congenital heart disease: anatomic and phenotypic spectrum and current approach to management. Circulation. 2018;137:508–18. 171. Kasper J, Bolliger D, Skarvan K, Buser P, Filipovic M, Seeberger MD.  Additional cross-sectional transesophageal echocardiography views improve perioperative right heart assessment. Anesthesiology. 2012;117:726–34. 172. Rudski LG, Lai WW, Afilalo J, et al. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr. 2010;23:685–713.

606 173. Lu X, Nadvoretskiy V, Bu L, et al. Accuracy and reproducibility of real-time three-dimensional echocardiography for assessment of right ventricular volumes and ejection fraction in children. J Am Soc Echocardiogr. 2008;21:84–9. 174. Grewal J, Majdalany D, Syed I, Pellikka P, Warnes CA.  Three-­ dimensional echocardiographic assessment of right ventricular volume and function in adult patients with congenital heart disease: comparison with magnetic resonance imaging. J Am Soc Echocardiogr. 2010;23:127–33. 175. Leibundgut G, Rohner A, Grize L, et  al. Dynamic assessment of right ventricular volumes and function by real-time three-­ dimensional echocardiography: a comparison study with magnetic resonance imaging in 100 adult patients. J Am Soc Echocardiogr. 2010;23:116–26. 176. Tamborini G, Marsan NA, Gripari P, et al. Reference values for right ventricular volumes and ejection fraction with real-time three-dimensional echocardiography: evaluation in a large series of normal subjects. J Am Soc Echocardiogr. 2010;23:109–15. 177. Dragulescu A, Grosse-Wortmann L, Fackoury C, Mertens L.  Echocardiographic assessment of right ventricular volumes: a comparison of different techniques in children after surgical repair of tetralogy of Fallot. Eur Heart J Cardiovasc Imaging. 2012;13:596–604. 178. Maffessanti F, Muraru D, Esposito R, et al. Age-, body size-, and sex-specific reference values for right ventricular volumes and ejection fraction by three-dimensional echocardiography: a multicenter echocardiographic study in 507 healthy volunteers. Circ Cardiovasc Imaging. 2013;6:700–10. 179. Renella P, Marx GR, Zhou J, Gauvreau K, Geva T. Feasibility and reproducibility of three-dimensional echocardiographic assessment of right ventricular size and function in pediatric patients. J Am Soc Echocardiogr. 2014;27:903–10. 180. Fusini L, Tamborini G, Gripari P, et al. Feasibility of intraoperative three-dimensional transesophageal echocardiography in the evaluation of right ventricular volumes and function in patients undergoing cardiac surgery. J Am Soc Echocardiogr. 2011;24:868–77. 181. Nishimura RA, Tajik AJ. Evaluation of diastolic filling of left ventricle in health and disease: Doppler echocardiography is the clinician’s Rosetta Stone. J Am Coll Cardiol. 1997;30:8–18. 182. Schmitz L, Koch H, Bein G, Brockmeier K. Left ventricular diastolic function in infants, children, and adolescents. Reference values and analysis of morphologic and physiologic determinants of echocardiographic Doppler flow signals during growth and maturation. J Am Coll Cardiol. 1998;32:1441–8. 183. Bernard F, Denault A, Babin D, et al. Diastolic dysfunction is predictive of difficult weaning from cardiopulmonary bypass. Anesth Analg. 2001;92:291–8. 184. Swaminathan M, Nicoara A, Phillips-Bute BG, et al. Utility of a simple algorithm to grade diastolic dysfunction and predict outcome after coronary artery bypass graft surgery. Ann Thorac Surg. 2011;91:1844–50. 185. Border WL, Michelfelder EC, Glascock BJ, et al. Color M-mode and Doppler tissue evaluation of diastolic function in children: simultaneous correlation with invasive indices. J Am Soc Echocardiogr. 2003;16:988–94. 186. Nagueh SF, Smiseth OA, Appleton CP, et al. Recommendations for the evaluation of left ventricular diastolic function by echocardiography: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2016;29:277–314. 187. Gidding SS, Snider AR, Rocchini AP, Peters J, Farnsworth R. Left ventricular diastolic filling in children with hypertrophic cardiomyopathy: assessment with pulsed Doppler echocardiography. J Am Coll Cardiol. 1986;8:310–6. 188. Olivier M, O’Leary PW, Pankratz VS, et al. Serial Doppler assessment of diastolic function before and after the Fontan operation. J Am Soc Echocardiogr. 2003;16:1136–43.

W. C. Miller-Hance and A. Vegas 189. McMahon CJ, Nagueh SF, Pignatelli RH, et al. Characterization of left ventricular diastolic function by tissue Doppler imaging and clinical status in children with hypertrophic cardiomyopathy. Circulation. 2004;109:1756–62. 190. Fazio G, Pipitone S, Iacona MA, et al. Evaluation of diastolic function by the tissue Doppler in children affected by non-­compaction (letter). Int J Cardiol. 2007;116:e60–2. 191. Harahsheh A, Aggarwal S, Pettersen MD, L’Ecuyer T. Diastolic function in anthracycline-treated children. Cardiol Young. 2015;25:1130–5. 192. Yim DL, Jones BO, Alexander PM, d’Udekem Y, Cheung MM.  Effect of anti-heart failure therapy on diastolic function in children with single-ventricle circulations. Cardiol Young. 2015;25:1293–9. 193. Castello R, Pearson AC, Lenzen P, Labovitz AJ.  Evaluation of pulmonary venous flow by transesophageal echocardiography in subjects with a normal heart: comparison with transthoracic echocardiography. J Am Coll Cardiol. 1991;18:65–71. 194. Margossian R, Sleeper LA, Pearson GD, et al. Assessment of diastolic function in single-ventricle patients after the Fontan procedure. J Am Soc Echocardiogr. 2016;29:1066–73. 195. Nadorlik H, Stiver C, Khan S, et al. Correlations between echocardiographic systolic and diastolic function with cardiac catheterization in biventricular congenital heart patients. Pediatr Cardiol. 2016;37:765–71. 196. Mawad W, Friedberg MK. The continuing challenge of evaluating diastolic function by echocardiography in children: developing concepts and newer modalities. Curr Opin Cardiol. 2017;32:93–100. 197. DiLorenzo M, Hwang WT, Goldmuntz E, Ky B, Mercer-Rosa L.  Diastolic dysfunction in tetralogy of Fallot: comparison of echocardiography with catheterization. Echocardiography. 2018;35:1641–8. 198. Smith JS, Cahalan MK, Benefiel DJ, et al. Intraoperative detection of myocardial ischemia in high-risk patients: electrocardiography versus two-dimensional transesophageal echocardiography. Circulation. 1985;72:1015–21. 199. van Daele ME, Sutherland GR, Mitchell MM, et al. Do changes in pulmonary capillary wedge pressure adequately reflect myocardial ischemia during anesthesia? A correlative preoperative hemodynamic, electrocardiographic, and transesophageal echocardiographic study. Circulation. 1990;81:865–71. 200. Moisés VA, Mesquita CB, Campos O, et al. Importance of intraoperative transesophageal echocardiography during coronary artery surgery without cardiopulmonary bypass. J Am Soc Echocardiogr. 1998;11:1139–44. 201. Balaguru D, Auslender M, Colvin SB, Rutkowski M, Artman M, Phoon CK.  Intraoperative myocardial ischemia recognized by transesophageal echocardiography monitoring in the pediatric population: a report of 3 cases. J Am Soc Echocardiogr. 2000;13:615–8. 202. Rouine-Rapp K, Rouillard KP, Miller-Hance W, et al. Segmental wall-motion abnormalities after an arterial switch operation indicate ischemia. Anesth Analg. 2006;103:1139–46. 203. Wong D, Golding F, Hess L, et al. Intraoperative coronary artery pulse Doppler patterns in patients with complete transposition of the great arteries undergoing the arterial switch operation. Am Heart J. 2008;156:466–72. 204. Nield LE, Dragulescu A, MacColl C, et  al. Coronary artery Doppler patterns are associated with clinical outcomes post-­ arterial switch operation for transposition of the great arteries. Eur Heart J Cardiovasc Imaging. 2018;19:461–8. 205. Benson MJ, Cahalan MK.  Cost-benefit analysis of transesophageal echocardiography in cardiac surgery. Echocardiography. 1995;12:171–83. 206. Siwik ES, Spector ML, Patel CR, Zahka KG.  Costs and cost-­ effectiveness of routine transesophageal echocardiography in congenital heart surgery. Am Heart J. 1999;138:771–6.

18  Intraoperative and Postoperative Applications 207. Bettex DA, Prêtre R, Jenni R, Schmid ER.  Cost-effectiveness of routine intraoperative transesophageal echocardiography in pediatric cardiac surgery: a 10-year experience. Anesth Analg. 2005;100:1271–5. 208. Levin DN, Taras J, Taylor K. The cost effectiveness of transesophageal echocardiography for pediatric cardiac surgery: a systematic review. Paediatr Anaesth. 2016;26:682–93. 209. Seward JB, Khandheria BK, Oh JK, Freeman WK, Tajik AJ.  Critical appraisal of transesophageal echocardiography: limitations, pitfalls, and complications. J Am Soc Echocardiogr. 1992;5:288–305. 210. Konstadt SN, Reich DL, Quintana C, Levy M.  The ascending aorta: how much does transesophageal echocardiography see? Anesth Analg. 1994;78:240–4. 211. Khandheria BK, Seward JB, Tajik AJ. Critical appraisal of transesophageal echocardiography: limitations and pitfalls. Crit Care Clin. 1996;12:235–51. 212. Dragulescu A, Golding F, Van Arsdell G, et al. The impact of additional epicardial imaging to transesophageal echocardiography on intraoperative detection of residual lesions in congenital heart surgery. J Thorac Cardiovasc Surg. 2012;143:361–7. 213. Kim HK, Kim WH, Hwang SW, et al. Predictive value of intraoperative transesophageal echocardiography in complete atrioventricular septal defect. Ann Thorac Surg. 2005;80:56–9. 214. le Polain de Waroux JB, Pouleur AC, Robert A, et al. Mechanisms of recurrent aortic regurgitation after aortic valve repair: predictive value of intraoperative transesophageal echocardiography. JACC Cardiovasc Imaging. 2009;2:931–9. 215. Hanna BM, El-Hewala AA, Gruber PJ, Gaynor JW, Spray TL, Seliem MA. Predictive value of intraoperative diagnosis of residual ventricular septal defects by transesophageal echocardiography. Ann Thorac Surg. 2010;89:1233–7. 216. Stern KW, White MT, Verghese GR, Del Nido PJ, Geva T.  Intraoperative echocardiography for congenital aortic valve repair: predictors of early reoperation. Ann Thorac Surg. 2015;100:678–85. 217. Redlin M, Miera O, Habazettl H, et  al. Incidence and echocardiographic predictors of early postoperative right ventricular dysfunction following left ventricular assist implantation in paediatric patients. Interact Cardiovasc Thorac Surg. 2017;25:887–91. 218. Kaushal SK, Radhakrishanan S, Dagar KS, et  al. Significant intraoperative right ventricular outflow gradients after repair for tetralogy of Fallot: to revise or not to revise. Ann Thorac Surg. 1999;68:1705–12. 219. Yang SG, Novello R, Nicolson S, et al. Evaluation of ventricular septal defect repair using intraoperative transesophageal echocardiography: frequency and significance of residual defects in infants and children. Echocardiography. 2000;17:681–4. 220. Lee HR, Montenegro LM, Nicolson SC, Gaynor JW, Spray TL, Rychik J.  Usefulness of intraoperative transesophageal echocardiography in predicting the degree of mitral regurgitation secondary to atrioventricular defect in children. Am J Cardiol. 1999;83:750–3. 221. Honjo O, Kotani Y, Osaki S, et al. Discrepancy between intraoperative transesophageal echocardiography and postoperative transthoracic echocardiography in assessing congenital valve surgery. Ann Thorac Surg. 2006;82:2240–6. 222. Shoiab I, Danford DA, Li L, Abdullah I, Hammel JM, Kutty S.  Predischarge transthoracic echocardiography after surgery for congenital heart disease: a routine with a reason. J Am Soc Echocardiogr. 2015;28:1030–5. 223. Oh JK, Seward JB, Khandheria BK, et  al. Transesophageal echocardiography in critically ill patients. Am J Cardiol. 1990;66:1492–5. 224. Font VE, Obarski TP, Klein AL, et  al. Transesophageal echocardiography in the critical care unit. Cleve Clin J Med. 1991;58:315–22.

607 225. Foster E, Schiller NB. The role of transesophageal echocardiography in critical care: UCSF experience. J Am Soc Echocardiogr. 1992;5:368–74. 226. Khoury AF, Afridi I, Quinones MA, Zoghbi WA. Transesophageal echocardiography in critically ill patients: feasibility, safety, and impact on management. Am Heart J. 1994;127:1363–71. 227. Poelaert J, Schmidt C, Van Aken H, Colardyn F. Transoesophageal echocardiography in critically ill patients. A comprehensive approach. Eur J Anaesthesiol. 1997;14:350–8. 228. Hüttemann E, Schelenz C, Kara F, Chatzinikolaou K, Reinhart K.  The use and safety of transoesophageal echocardiography in the general ICU—a minireview. Acta Anaesthesiol Scand. 2004;48:827–36. 229. Hüttemann E.  Transoesophageal echocardiography in critical care. Minerva Anestesiol. 2006;72:891–913. 230. Ananthasubramaniam K, Jaffery Z. Postoperative right atrial compression by extracardiac hematoma: transesophageal echocardiographic diagnosis in the critically ill patient. Echocardiography. 2007;24:661–3. 231. Arntfield R, Lau V, Landry Y, Priestap F, Ball I. Impact of critical care transesophageal echocardiography in medical-surgical ICU patients: characteristics and results from 274 consecutive examinations. J Intensive Care Med. 2018;35(9):896–902. 232. Wolfe LT, Rossi A, Ritter SB. Transesophageal echocardiography in infants and children: use and importance in the cardiac intensive care unit. J Am Soc Echocardiogr. 1993;6:286–9. 233. Marcus B, Wong PC, Wells WJ, Lindesmith GG, Starnes VA. Transesophageal echocardiography in the postoperative child with an open sternum. Ann Thorac Surg. 1994;58:235–6. 234. Scheinin SA, Radovancevic B, Ott DA, Nihill MR, Cabalka A, Frazier OH. Postcardiotomy LVAD support and transesophageal echocardiography in a child. Ann Thorac Surg. 1993;55:529–31. 235. Kocabas S, Askar FZ, Yagdi T, Engin C, Ozbaran M. Anesthesia for ventricular assist device placement in pediatric patients: experience from a single center. Transplant Proc. 2013;45:1009–12. 236. Crowley J, Cronin B, Essandoh M, D’Alessandro D, Shelton K, Dalia AA.  Transesophageal echocardiography for Impella placement and management. J Cardiothorac Vasc Anesth. 2019;33:2663–8. 237. Baillard C, Cohen Y, Fosse JP, Karoubi P, Hoang P, Cupa M.  Haemodynamic measurements (continuous cardiac output and systemic vascular resistance) in critically ill patients: transoesophageal Doppler versus continuous thermodilution. Anaesth Intensive Care. 1999;27:33–7. 238. Feinberg MS, Hopkins WE, Davila-Roman VG, Barzilai B. Multiplane transesophageal echocardiographic Doppler imaging accurately determines cardiac output measurements in critically ill patients. Chest. 1995;107:769–73. 239. Patel JK, Glatz AC, Ghosh RM, et al. Accuracy of transesophageal echocardiography in the identification of postoperative intramural ventricular septal defects. J Thorac Cardiovasc Surg. 2016;152:688–95. 240. Douglas PS, Khandheria B, Stainback RF, et  al. ACCF/ASE/ ACEP/ASNC/SCAI/SCCT/SCMR 2007 Appropriateness criteria for transthoracic and transesophageal echocardiography: a report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group, American Society of Echocardiography, American College of Emergency Physicians, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and the Society for Cardiovascular Magnetic Resonance endorsed by the American College of Chest Physicians and the Society of Critical Care Medicine. J Am Coll Cardiol. 2007;50:187–204. 241. Douglas PS, Garcia MJ, Haines DE, et  al. ACCF/ASE/AHA/ ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 Appropriate Use Criteria for Echocardiography. A Report of the American

608

W. C. Miller-Hance and A. Vegas College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical

Care Medicine, Society of Cardiovascular Computed Tomography, and Society for Cardiovascular Magnetic Resonance. J Am Coll Cardiol. 2011;57:1126–66. 242. McGuinness GA, Schieken RM, Maguire GF. Endocarditis in the newborn. Am J Dis Child. 1980;134:577–80.

Other Applications, Including the Critical Care Setting

19

Pei-Ni Jone and Adel Younoszai

Abbreviations

Introduction

2D Two-dimensional 3D Three-dimensional CHD Congenital heart disease CHF Congestive heart failure DVI Doppler velocity index EOA Effective orifice area IE Infective endocarditis PPM Patient-prosthesis mismatch SVC Superior vena cava TAVR Transcatheter aortic valve replacement TEE Transesophageal echocardiography THV Transcatheter heart valve TTE Transthoracic echocardiography VTI Velocity time integral

The vast majority of transesophageal echocardiography (TEE) studies performed in pediatric patients with acquired or congenital heart disease (CHD) is generally performed during operative or interventional procedures. The same holds true for a large proportion of adult patients with CHD.  Nonetheless, there are other settings in which TEE can prove beneficial in such patients. This chapter focuses on other applications of TEE in pediatric and adult patients with and without CHD, including the critical care setting. Frequently, TEE is used in critically ill patients who have poor acoustic windows. We will discuss the most common indications for TEE in this setting, including evaluation for infective endocarditis, cardiac thrombi after CHD surgery, and prosthetic valves.

Key Learning Objectives

Infective Endocarditis

• Describe the echocardiographic manifestations of infective endocarditis (IE) • Define the role of transesophageal echocardiography (TEE) for the evaluation of IE, and its use compared to transthoracic echocardiography • Outline the key echocardiographic characteristics of intracardiac thrombus, and how they are evaluated by TEE • Distinguish the key differences between mechanical and bioprosthetic valves • Review the methodology for echocardiographic evaluation of mechanical valves

Infective endocarditis (IE) is a bacterial or fungal infection of the endocardium of the heart  and great vessels, and usually occurs in the setting of a preexisting abnormality of the heart or great arteries [1]. It may occur in a normal heart during septicemia or as a consequence of infected indwelling central catheters [1]. Common organisms causing IE are Streptococcus viridans (30–40% of cases), Staphylococcus aureus (25–30%), and fungal agents (about 5%). The infectious process is highly invasive and can cause destruction of heart valves and surrounding tissue. It can lead to intramyocardial abscess, congestive heart failure (CHF) from valve regurgitation, systemic and pulmonary emboli, sepsis, arrhythmias, myocardial failure, and even death [2]. In the pediatric population, the frequency of infective endocarditis (IE) appears to be increasing [1] for several reasons: (1) increased survival in children with CHD, (2) greater use of central venous catheters, and (3) increased use of prosthetic material and valves. Pediatric patients without preexisting heart disease are also at increased risk for IE because of (1) increased survival rates for children with immune deficiencies, (2) long-term use of

Electronic Supplementary Material The online version of this chapter (https://doi.org/10.1007/978-­3-­030-­57193-­1_19) contains supplementary material, which is available to authorized users. P.-N. Jone (*) · A. Younoszai Pediatric Cardiology, Children’s Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, USA e-mail: [email protected]; [email protected]

© Springer Nature Switzerland AG 2021 P. C. Wong, W. C. Miller-Hance (eds.), Transesophageal Echocardiography for Pediatric and Congenital Heart Disease, https://doi.org/10.1007/978-3-030-57193-1_19

609

610

P.-N. Jone and A. Younoszai

Table 19.1  Modified Duke Criteria: Definition of terms used for the diagnosis of infective endocarditis (IE) (Modifications to original Duke criteria shown in boldface) Major criteria Blood culture positive for IE     Typical microorganisms consistent with IE from 2 separate blood cultures:         Viridans streptococci, Streptococcus bovis, HACEK group, Staphylococcus aureus; or         Community-acquired enterococci, in the absence of a primary focus; or     Microorganisms consistent with IE from persistently positive blood cultures, defined as follows:         At least 2 positive cultures of blood samples drawn >12 h apart; or         All of 3 or a majority of ≥4 separate cultures of blood (with first and last sample drawn at least 1 h apart)     Single positive blood culture for Coxiella burnetii or antiphase I IgG antibody titer > 1:800 Evidence of endocardial involvement Echocardiogram positive for IE (TEE recommended in patients with prosthetic valves, rated at least “possible IE” by clinical criteria, or complicated IE [paravalvular abscess]; TTE as first test in other patients), defined as follows:         Oscillating intracardiac mass on valve or supporting structures, in the path of regurgitant jets, or on implanted material in the absence of an alternative explanation; or         Abscess; or         New partial dehiscence of prosthetic valve New valvular regurgitation (worsening or changing of pre-existing murmur not sufficient) Minor criteria Predisposition, predisposing heart condition or injection drug use Fever, temperature > 38 °C. Vascular phenomena, major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, and Janeway’s lesions Immunologic phenomena: glomerulonephritis, Osler’s nodes, Roth’s spots, and rheumatoid factor Microbiological evidence: positive blood culture but does not meet a major criterion as noted abovea or serological evidence of active infection with organism consistent with IE Echocardiographic minor criteria eliminated Note: TEE, transesophageal echocardiography; TTE, transthoracic echocardiography a Excludes single positive cultures for coagulase-negative staphylococci and organisms that do not cause endocarditis From: Li JS, et al. [10]. Reproduced with permission, Oxford University Press Table 19.2  Definition of Endocarditis from modified Duke criteria (Modifications to original Duke criteria shown in boldface) Definite infective endocarditis Pathologic criteria (1)  Microorganisms demonstrated by culture or histologic examination of a vegetation, a vegetation that has embolized, or an intracardiac abscess specimen; or (2)  Pathologic lesions; vegetation or intracardiac abscess confirmed by histologic examination showing active endocarditis Clinical criteriaa (1)  2 major criteria; or (2)  1 major criterion and 3 minor criteria; or (3)  5 minor criteria Possible infective endocarditis (1)  1 major criterion and 1 minor criterion; or (2)  3 minor criteria Rejected (1)  Firm alternate diagnosis explaining evidence of infective endocarditis; or (2)  Resolution of infective endocarditis syndrome with antibiotic therapy for ≤4 days; or (3)  No pathologic evidence of infective endocarditis at surgery or autopsy, with antibiotic therapy for ≤4 days; or (4)  Does not meet criteria for possible infective endocarditis, as above See Table 19.1 for definitions of major and minor criteria From: Li JS, et al. [10]. Reproduced with permission, Oxford University Press

a

indwelling lines in ill newborns and patients with chronic diseases, and (3) increased intravenous drug abuse. Over the past 2 decades, CHD has become the predominant condition for IE in children greater 2  years of age in developed countries [3]. Before 1970, it was estimated that 30–50% of pediatric IE cases in the United States had underlying rheumatic heart disease [4]. However, it is unusual

now to have IE from rheumatic heart disease in developed countries. Patients at greatest risk of IE are children with unrepaired or palliated CHD (ventricular septal defect, aortic valve abnormalities, patent ductus arteriosus, tetralogy of Fallot), those with implanted prosthetic material, and patients who have had a prior episode of IE [3, 5–7]. An increasing number of children with IE have had previous sur-

19  Other Applications, Including the Critical Care Setting

gery for CHD, and postoperative IE is a long-term risk after corrective surgery for complex cyanotic CHD when there is a residual defect or when surgical shunts or prosthetic materials have been left in place [1]. It can also occur in the absence of structural heart disease in neonates and pediatric patients with complex medical problems requiring indwelling central catheters, accounting for 8–10% of pediatric cases [8, 9]. In older patients, IE without CHD accounts for 25–45% of cases [8]. The diagnosis of IE is not always straightforward. To assist in the diagnosis, the modified Duke criteria are utilized; these criteria incorporate clinical, laboratory, pathologic, and echocardiographic evaluation (Table  19.1) [10]. The Duke criteria stratify patients into three main categories of definite IE, possible IE, and rejected IE based upon the presence of major and minor criteria (Table 19.2). Echocardiography— both transthoracic echocardiography (TTE) or TEE—is an important major criterion in the diagnosis of IE with special emphasis in the use of TEE in prosthetic valves or when the diagnosis is rated as possible IE by clinical criteria (Tables 19.1 and 19.2). Studies have demonstrated that when clinical evidence of IE is present, TEE improves the sensitivity of the Duke criteria to diagnose definite IE. The positive predictive value of the Duke criteria with TEE data for diagnosis of IE was 85% in patients with native valves and 89% in patients with prosthetic valves [11]. In adults, studies have demonstrated that the diagnostic sensitivity of TEE in IE is superior than TTE [12–19]. This is particularly true when IE is due to endocarditis of a prosthetic valve, an intracardiac abscess, and poor acoustic windows [17, 20]. In pediatric patients, the advantage of TEE over TTE is less apparent when TTE provides excellent imaging acoustic windows in infants and younger children. In general, TTE is considered adequate for the diagnosis of IE in young children, and TEE is reserved for those children with suboptimal imaging windows or inadequate TTE studies [21, 22].

a

611

Echocardiographic Manifestations of IE The echocardiographic manifestations of IE include vegetations, valvular dysfunction, intracardiac abscesses, aneurysm formation, fistulous tracts, CHF, and/or pericardial effusions. Vegetations are the most characteristic findings of endocarditis. They are a mass of pathologic organisms nestled in platelets, red blood cells, and fibrin. Vegetations frequently are found in areas where the endothelium has been injured or disrupted by a  high velocity jet or intravenous catheter. These can occur on valve surfaces but can also occur on cardiac chambers when the endothelial surface has been damaged (Figs.  19.1, 19.2, 19.3, 19.4, 19.5, Videos 19.1, 19.2, 19.3, 19.4, 19.5, 19.6). Vegetations can also occur on foreign materials such as prosthetic valve, conduit, shunts, or patches. The surface of the injured endothelium or prosthetic material serves as a nidus for platelet or fibrin deposition producing a thrombus at the site, initially sterile. With bacteremia, the circulating microorganisms can become adherent to meshwork resulting in an  infected vegetation. More fibrin and platelet deposits occur, thus shielding the microorganism from host defense and allowing them to proliferate rapidly and produce further growth of the vegetation [1, 23, 24]. Vegetations can have a number of detrimental effects: (a) they can grow and destroy adjacent tissue; (b) organisms can be released continuously into the bloodstream, leading to persistent bacteremia and hematogenous seeding of remote sites; (c) pieces of the vegetation can break off and embolize to other organs (brain, lung, kidney), sometimes producing serious and even devastating complications; (d) antibody response to the infecting organisms leads to subsequent tissue injury by immune complex deposition [25]. By echocardiography, vegetations present as echogenic masses that are irregular in shape and variable in size, frequently located on the affected valve or nonvalvular structure or downstream to a high velocity jet (e.g. near a ventricular septal defect or valvar regurgitant jet). They are usually freely mobile, b

Fig. 19.1  Large vegetation (arrow) on the anterior leaflet of mitral valve (a), which resulted in chordal destruction and severe mitral regurgitation (b). Midesophageal four-chamber view (transducer angle 0°). LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

612

a

Fig. 19.2  Aortic valve endocarditis, seen from a midesophageal aortic valve long axis view (transducer angle 85°–106°). (a) Shows a prominent vegetation (arrow) on the left coronary cusp, which has caused

Fig. 19.3  A patient with Staphylococcus aureus bacteremia who had a transthoracic echocardiogram showing a large mass on the aortic valve with fibrinous strands. A vegetation is seen on the aortic valve from endocarditis in the midesophageal five-chamber view. There is a ventricular septal defect that occurred as a complication of the endocarditis, and color Doppler shows flow across the defect

oscillating with the cardiac cycle, and can move back and forth within the plane of the valve (Fig. 19.1, Video 19.1). Intracardiac vegetations are typically well seen by TEE. Valvular dysfunction from IE may result from ruptured chordae with prolapsing or flail leaflets, fenestrations in the valve cusps, or torn leaflets. All of these lead to disruption of valvar function and resultant valvar regurgitation, often to a significant degree. It is not uncommon to see vegetations in association with valvar disruption, as evidence of the destructive process from IE. Significant valvular regurgitation can progress to CHF with a  toxic appearance of the patient The amount of regurgitation can be evaluated by vena contracta width, and the regurgitant jet area or effective orifice obtained from color flow Doppler [26]. Examples of

P.-N. Jone and A. Younoszai

b

significant cusp destruction and resulted in severe aortic valve regurgitation (b). Ao ascending aorta, LA left atrium, LV left ventricle, RV right ventricle

valve disruption and accompanying vegetation are shown in Figs. 19.1 and 19.2, Videos 19.1 and 19.2. Intracardiac abscess forms when the infectious process extends to adjacent structures. Most commonly, this occurs with the aortic valve, when the infectious process extends into the weakest area of the annulus such as the membranous septum, potentially producing a ventricular septal defect (Fig.  19.3, Video 19.3). In some cases, the infectious process can involve the atrioventricular node, resulting in heart block. Perivalvar abscess formation can occur in 10–40% of all native IE, most commonly in the native aortic valve, and less commonly in the native tricuspid or mitral valve [27]. Perivalvar abscesses are seen in 56–100% of patients with prosthetic valve IE [27]. The echocardiographic appearance of abscess formation is an echo-free space with purulent fluid within the wall surrounding the affected valve or extending into the adjacent tissue. In patients with an abscess surrounding the prosthetic valve, there may be dehiscence of the valve. The preferred mode of evaluation of intracardiac abscess is TEE, which has been shown to yield a higher sensitivity than TTE for the diagnosis of abscesses associated with endocarditis [17]. An example of an abscess that formed around a prosthetic aortic valve is shown in Fig. 19.4, Video 19.4. Aneurysm formation occurs when the infectious process extends to an adjacent vessel wall, causing thinning and destruction of the wall (Fig. 19.5, Video 19.5). This is seen in native aortic valve IE, when the sinus of Valsalva and adjacent cardiac structure form a fistulous tract creating a sinus of Valsalva aneurysm or a fistulous tract forms into the pericardial space [28, 29]. In this setting, TEE will demonstrate the aneurysmal dilation of the vessel wall, and color flow Doppler will demonstrate systolic/diastolic (or continuous) flow between the aorta and the receiving chamber (Fig. 19.5, Video 19.5). Pseudoaneurysm formation can also occur in

19  Other Applications, Including the Critical Care Setting

613

a

b

c

d

Fig. 19.4  Endocarditis in a patient with a prosthetic aortic valve (St. Jude). (a, b) The midesophageal four-chamber view demonstrates a perivalvar abscess that extends into the noncoronary cusp, causing a fistulous tract communicating with the right atrium. A large vegetation (arrow) has developed in this area and shunting is seen into the right

a

Fig. 19.5  Infected sinus of Valsalva aneurysm from aortic valve endocarditis, obtained from the midesophageal long axis view. (a) Shows a large vegetation of the aortic valve (arrow) and erosion of the right sinus

atrium. (c, d) Modified midesophageal aortic valve long axis  view, angle about 90°. There is marked aortic regurgitation seen through an area of valve dehiscence (*). Ao aorta, LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

b

of Valsalva, producing a large aneurysm (An). (b) Shows blood filling the aneurysm during diastole. Ao ascending aorta, LA left ventricle, LV left ventricle

614

Fig. 19.6  Infected pseudoaneurysm off ascending aorta. This TEE was performed to evaluate the aortic valve in a patient with a previous aortic valve surgery and persistent fungemia. A large pseudoaneurysm (arrow) was discovered using the upper esophageal view, transducer angle 60°. In surgery, the pseudoaneurysm was found to be infected and filled with fungus. Note that the superior portion of aorta and innominate vein can be seen well in this patient by TEE.  Asc Ao, ascending aorta; In V, innominate vein

foreign material such as suture material and biologic grafts [30, 31] (Fig. 19.6, Video 19.6). Congestive heart failure is a complication of IE and is associated with poor prognosis [32, 33]. It can be  a result of valvular and myocardial dysfunction, septic emboli to the coronaries resulting in myocardial ischemia, sudden intracardiac shunts from fistula formation, or abscess formation resulting in heart block. Acute CHF is more frequently seen in left sided infections in the aortic valve (29%) and the mitral valve (20%) than in the tricuspid valve (8%) [27]. A pericardial effusion can also be seen in patients with IE; it can be infectious, resulting from hematogenous seeding of the pericardium, or as a direct extension from intracardiac IE (e.g. perforation of a perivalvar abscess). Rarely, it can be occur as a reactive/serous effusion [34].

Goals of TEE Imaging in IE The evaluation of IE by TEE can occur in several settings. It can be performed in the ICU or ambulatory setting, serving as either diagnostic evaluation for suspected IE or as a monitoring procedure for a patient receiving treatment for known IE. It also plays a vital role in the intraoperative setting. Preoperatively, TEE is used to assess not only the vegetation or abscess, but also valvar function and the surrounding cardiac structures. When applicable, prosthetic valve dehiscence and pseudoaneurysm formation can also be evaluated. Postoperatively, TEE is used to assess the results of operative repair or valve replacement, and guide perioperative hemodynamic management [34, 35]. The goals of TEE imaging in IE are to evaluate for vegetations, valvular dysfunction, intracardiac abscesses, aneu-

P.-N. Jone and A. Younoszai

rysm formation, fistulous tracts, abnormalities supporting congestive physiology, and/or pericardial effusions. A complete study with upper esophageal, midesophageal, transgastric, and deep transgastric views (Chap. 4) should be used to evaluate for manifestations of IE. If vegetations are found, the appearance and motion should be evaluated in multiple planes, and measurements made. The risk of emboli appears to be greatest when the vegetation is >10 mm on the anterior leaflet of the mitral valve [27]. Attention must be paid to valve leaflet anatomy and motion both by two-dimensional (2D) imaging and color flow Doppler. Valve perforation and chordal disruption must be inspected, and three-dimensional (3D) TEE imaging can be helpful in delineating the perforated site and chordal disruption with flail leaflets. In cases of aortic valve endocarditis, abscess and aneurysmal formation must be inspected. If IE occurs in prosthetic valves, then a thorough examination of the valve leaflet motion is mandatory, as well as inspection for any possible paravalvular leak around the sewing ring that might suggest perivalvar abscesses and dehiscence. Myocardial function and the presence of pericardial effusion should also be evaluated. Three caveats are important to consider. First, even with TEE, not all vegetations will be visible, particularly if the vegetations are smaller than the resolution limits of the TEE probe and/or TEE imaging is suboptimal. This is an important consideration in patients with operated and unoperated CHD, who can have vegetations located in areas not readily visible by TEE (e.g. a Blalock-Taussig shunt). Studies have shown that—irrespective of whether TTE or TEE is used—patients with CHD and IE are less likely to have visible vegetations [36]. Thus, the echocardiographic data should be considered in the context of the entire clinical picture, as noted with the Duke criteria listed above. In some cases, if IE is still suspected, a TTE or TEE can be performed 7–10 days later to determine if a vegetation or abscess has appeared [27, 36, 37]. The second important caveat is that not all echogenic masses represent vegetations. Sterile thrombi, tumors, irregular valve excrescences, and foreign material (such as suture material) can sometimes resemble vegetations. Again, the echocardiogram should be reviewed in conjunction with the entire clinical picture. Also, if previous echocardiograms are available (either transthoracic or transesophageal), these can be very useful to make direct comparisons to determine whether the abnormal finding is new or longstanding. New findings are much more suspicious for IE.  The last important caveat is that not all vegetations are infectious. A number of medical conditions can produce sterile vegetations adherent to valvar surfaces. Examples of such conditions include systemic lupus erythematosus (Libman-Sacks endocarditis), and nonbacterial thrombotic endocarditis (NBTE, also known as marantic endocarditis). The latter can occur as complication of malignancy, uremia, burns, hypercoagulable states, or autoimmune diseases, and it has been found in approximately 1.2% of all autopsy patients, although the reported incidence is between

19  Other Applications, Including the Critical Care Setting

615

0.3–9.3% [25, 38]. In fact, Libman-Sacks endocarditis is felt to be a form of NBTE [39]. These vegetations are usually seen on the valve closure contact line of the atrial surface of the atrioventricular (AV) valves, and the  ventricular surface of the semilunar valves. In many cases, the vegetations are benign and clinically unapparent. However, systemic embolization has been described in up to 30–50% of patients [38–40], with a tendency towards embolization to the brain, kidney, spleen, mesenteric bed, or extremities [39, 41].

Cardiac Thrombi Cardiac thrombi can occur in the setting of poor cardiac function and stasis of blood, especially in cases of dilated cardiomyopathy. The use of TEE is complementary to TTE assessment for thrombi in the pediatric population. Generally, cardiac thrombi can be seen by TTE except for those instances of poor acoustic windows (such as in intensive care patients). Thrombi can vary in echogenic appearance and location. They are echogenic, homogeneous in density, irregular in shape (they can be broad or pedunculated), and in some instances can have calcifications within the thrombus. They may attach to the endocardial surface or atrioventricular valve, or to foreign material. In patients with atrial arrhythmias such as atrial fibrillation, they can be located within the atrial appendages. In the critical care setting, they are commonly found at the end of an indwelling catheter near the innominate vein, superior vena cava (SVC), or right atrium. TEE can be used to evaluate the size, attachment point, and the extent of an SVC or right atrial thrombus. In the mid to upper esophageal views, the probe can be rotated rightward with angle to 90°, allowing for visualization of the sagittal plane of the SVC return to the right atrium. A catheter can be seen in this view, and if there is a thrombus, it can be visualized and the size should be measured (Fig. 19.7, Video 19.7). If there is obstruction to the SVC, then a deep transgastric view can be used with rightward turning and anteflexion of the probe, to achieve posterior angulation and visualize the SVC flow as it enters the right atrium. The mean gradient can be measured using spectral Doppler interrogation. Though less common in children, patients with atrial fibrillation or severe mitral stenosis can have thrombi in the left and right  atrial appendages [42–44]. In adult studies, the incidence of left atrial thrombus in patients with atrial fibrillation is between 10–15% and that of a right atrial thrombus of 0.4–7.5% [45]. These thrombi are often difficult to identify by TTE and can be difficult to distinguish from pectinate muscles [46]. The use of TEE provides excellent visualization of the left and right atrial appendages [47, 48]. The right atrial appendage can be examined in the midesophageal bicaval view, transducer angle 90°–

Fig. 19.7  Thrombus (arrow) in the superior vena cava, probably associated with a catheter. Seen from a modified  midesophageal bicaval view, (transducer angle 118°). LA left atrium, RA right atrium

Fig. 19.8  Modified midesophageal left atrial appendage view (transducer angle 55°) showing a thrombus (arrow) in the left atrial appendage (LAA) in a patient with atrial fibrillation. LA left atrium, LUPV left upper pulmonary vein

110°, and it is seen anterior to the SVC/right atrial junction. The transducer angle can then be rotated to 0° to visualize the right atrial appendage from a different plane. The left atrial appendage can be viewed in the midesophageal left atrial appendage (ME LAA) view with leftward probe rotation and a transducer angle of 90° (although the transducer angle can be varied from 0° to 90° for optimal visualization of the thrombus) (Fig. 19.8, Video 19.8). Live 3D imaging can also be used, rotating the image so that the left atrial appendage can be seen in different views. It is important to inspect both the right and left atrial appendages to distinguish thrombi from pectinate muscles, crista terminalis, Chiari network, and Eustachian valves—all of which are normal anatomic components found in the atria and atrial appendages [47, 49–51].

616

P.-N. Jone and A. Younoszai

Fig. 19.9  Examples of bileaflet (St Jude, a), single-leaflet (Medtronic-­ Hall, b), and caged-ball (Starr-Edwards, c) mechanical valves and their transesophageal echocardiographic characteristics taken in the mitral position in diastole (middle) and in systole (right). The arrows in dias-

tole point to the occluder mechanism of the valve and in systole to the characteristic physiologic regurgitation observed with each valve. Reprinted from Zoghbi et al. [52]; with permission from Elsevier

Prosthetic Valves

alive, and continue to be followed regularly. The second type of mechanical valve is the monoleaflet valve, in which a single disk is secured by lateral or central metal struts, and surrounded by a sewing ring. The disk, generally made of extremely hard carbon (pyrolytic carbon), opens by tilting at an angle (about 60°–80°), resulting in 2 orifices of different sizes. Typical examples of this include the Bjork-Shiley (discontinued), and the Medtronic-Hall valve (Fig. 19.9b). The third major type of mechanical valve is the bileaflet tilting disk valve, made of two semicircular pyrolytic carbon disks attached by hinges to a rigid valve sewing ring. In the open position the valve leaflets tilt to an opening angle of 75°–90°, resulting in three orifices: a small slit-like orifice centrally between the two leaflets, and two semicircular orifices laterally. Of the three types of mechanical valves, this type provides the most natural blood flow, greater effective orifice area for a given valve size,

There are two types of prosthetic valves, mechanical and biologic, that are used for surgery (both mechanical and biologic); biologic valves are used for  transcatheter valve replacement. Mechanical heart valves contain nonbiologic materials (polymers, metal, carbon) in all parts of the ­prosthesis: the valve ring, sewing cuff, and orifice occluder. A number of mechanical valves have been developed over the past 50 years, essentially of three major types. The first type to be developed was the caged ball valve, consisting of a silastic ball with a circular sewing ring and a cage formed by 3 metal arches. The most notable of these was the Starr-­Edwards valve (Fig. 19.9c), though similar valves have been produced including the Smeloff-Cutter valve. While these valves are no longer implanted, many patients who received these valves are still

19  Other Applications, Including the Critical Care Setting

and is also the least thrombogenic. Currently, the most commonly implanted mechanical valves are the bileaflet valves, notably the St. Jude Medical (Fig.  19.9a) and Carbomedics bileaflet tilting disk valves. They are available in a variety of sizes (from 15–33 mm) suitable for both pediatric and adult patients. The mechanical valves have a proven record of durability, though they require ongoing anticoagulation therapy, and there are ever-present risks of thrombosis and endocarditis of the valve. In many types of mechanical valves, separate aortic and mitral versions are available. However, for a number of the mechanical valves, implantation has been performed in any of the four valve positions. Biologic heart valves are derived from human or animal tissue, and certain valves contain nonbiologic material as well, such as metal and fabric. Human tissue valves fall into two categories: homografts (allografts) and autografts. Homograft valves are cryopreserved cadaveric aortic and pulmonary valves, generally used as pulmonary or aortic valve replacements (Fig. 19.10). They come in a variety of sizes, depending upon donor availability. In contrast, an autograft represents the patient’s own valve translocated from one site to another. Usually, the autograft is the pulmonary valve translocated to the aortic position (Ross procedure) or rarely the mitral position (Ross II), with a homograft valve being placed in the original pulmonary position [53–55]. Biologic valves derived from animal tissue are known as xenograft (or heterograft) valves; the most commonly used animal tissues are porcine aortic valve and bovine pericardium, and the tissues are fixed with glutaraldehyde. These valves come in two major forms. Stented biologic valves contain a sewing ring and struts composed of nonbiologic material (metal, cloth), and valve tissue is sewn onto the fabric covering the struts.

Fig. 19.10  Aortic homograft, following thawing and prior to implantation as a right ventricle to pulmonary artery conduit

617

Both porcine valve (Fig. 19.11a) and bovine pericardium are used with these types of valves. Stentless biologic valves contain no struts or sewing ring, which leaves more room for blood flow. Stentless xenograft valves derive primarily from harvested porcine aortic valves (Fig. 19.11b). Of note, human homograft and autograft valves fall into the category of unstented biologic valves, since they contain no sewing ring or struts. This is because the entire homograft/allograft root (containing the valves) is harvested, thus the intrinsic structural support for the valve leaflets remains intact. Another category of bioprosthesis that has gained popularity is the Contegra pulmonary valve conduit. The Contegra conduit is a bovine jugular vein preserved in glutaraldehyde, and it contains a valve with three leaflets; the leaflets are similar to a human semilunar valve (Fig. 19.12). Since it is derived from a venous vascular structure, it is felt to be best suited for conditions of lower pressure such as the pulmonary circuit, and therefore it is used primarily for congenital heart surgeries in which a right ventricle to pulmonary artery conduit is needed such as the Ross procedure, tetralogy of Fallot, truncus arteriosus, etc. [56]. Thus it serves as an alternative to the homograft, and has achieved comparable short to intermediate term results [57–59]. Strictly speaking, it is a valved conduit (not solely a biologic valve), but it is used in a number of operations in which a valve is necessary. As will be discussed below, the bovine jugular valve is also used for transcatheter valve technology. Over the years, a large number of different valve prostheses (both mechanical and biologic) have been developed, in a variety of valve sizes and profiles. Development continues at a rapid pace, with novel alternatives currently in development or advanced clinical trials. A list of some of the better-known biologic and mechanical valves is given in Table 19.3; this list is by no means exhaustive, and new models and types are periodically being introduced. A full discussion and elaboration of the many individual valves would require a separate chapter. For further discussion, the reader is referred to a number of references providing more detailed coverage of the topic [60–64]. Both mechanical and biologic valves can be used to replace a stenotic or regurgitant valve in any of the four valve positions. The preference for valve replacement type varies depending upon the desired site of implantation, and includes considerations such as age of the patient, evidence-based effectiveness of valve prosthesis alternatives for the intended valvar position, valve durability, valve size availability, and the need for ongoing medical therapy. Mechanical prostheses boast greater durability, but this must be balanced with the need for constant anticoagulation and the ever-present risks of bleeding, thrombosis and endocarditis. Conversely, biologic valves do not generally require significant anticoagulation, but their durability can be much more variable. While there are multiple options for each valve site, some generalizations can be made [65]. For pulmonary valve

618

P.-N. Jone and A. Younoszai

a

b

c

Fig. 19.11  Examples of stented (a), stentless (b), and percutaneous biologic valves (Edwards SAPIEN, c) and their echocardiographic features in diastole (middle) and in systole (right) as seen by TEE.  The

stentless valve is inserted by the root inclusion technique. Mild paravalvular aortic regurgitation in the percutaneous valve is shown by arrow. Reprinted from Zoghbi et al. [52]; with permission from Elsevier

replacement, biologic valves—notably homograft (allograft) and heterograft (porcine, bovine pericardial)—are g­ enerally preferred, though some investigators have advocated for mechanical valves [66]. For tricuspid, either a mechanical valve or stented porcine valve is generally used. For the aortic valve, both biologic (homograft, heterograft, pulmonary autograft) and mechanical prosthetic valves are utilized. A number of stented and unstented bioprosthetic xenograft valves have been developed for the aortic valve position. For the mitral valve, mechanical prostheses predominate in children and adults, although stented biologic valves (porcine and bovine pericardial) are selectively used in the adult group due to other important considerations (such as pregnancy and the risk of warfarin embryopathy) [65].

One of the most important and exciting new areas in prosthetic valve technology has been the development of catheter-based, implantable prosthetic valves, also known as transcatheter heart valves or THVs. Valve leaflets composed of biologic tissue are mounted in an expandable metal frame, which can then be delivered using various transcatheter techniques and precisely placed in the location of the diseased or absent valve. Several of these THVs are well-known, having already gained a large clinical experience. The Melody valve is a bovine jugular valve mounted on a platinum iridium stent, and delivered by a 22 F balloon in balloon catheter delivery system [67]. It is primarily designed for pulmonary valve replacement, and in the United States it is currently used only in an existing right ventricular outflow conduit,

19  Other Applications, Including the Critical Care Setting Fig. 19.12  Contegra bovine jugular vein, containing a trileaflet valve that is similar to a human semilunar valve

a

b

Table 19.3  Typical biologic and mechanical valves Valve name/type Manufacturer Biologic—Human Autograft Allograft (Homograft) Cryolife Monocusp, bicuspid Biologic—Heterograft Stented Hancock II Medtronic Mosaic Medtronic Carpentier-Edwards Edwards-Lifesciences Epic St Jude Biocor St Jude Trifecta St Jude Carpentier-Edwards Perimount Magna Edwards Lifesciences Mitroflow Sorin Biomedica Soprano Sorin Biomedica Inspiris Edwards Lifesciences Stentless Freestyle Medtronic Toronto SPV St Jude Prima Plus Edwards Lifesciences Pericarbon Freedom Sorin Biomedica 3F Therapeutics Stentless Equine 3F Therapeutics Mechanical Starr-Edwards Edwards Lifesciences Bjork-Shiley Pfizer Medtronic-Hall Medtronic St Jude Medical St Jude CarboMedics Sorin-CarboMedics ATS Medical ATS Medical On-X On-X Life Technologies Percutaneous—Biologic Melody Medtronic SAPIEN Edwards Lifesciences Evolut R (CoreValve) Lotus Other SynerGraft Contegra

619

Valve type/origin Pulmonary autograft Harvested cadaveric aortic, pulmonary homograft Surgically handsewn valve using autologous pericardium

Porcine Porcine Porcine Porcine Porcine Bovine pericardial Bovine pericardial Bovine pericardial Bovine pericardial Bovine pericardial Porcine Porcine Porcine Bovine pericardial Equine pericardial Ball-in-cage Single leaflet tilting disk Single leaflet tilting disk Bileaflet tilting disk Bileaflet tilting disk Bileaflet tilting disk Bileaflet tilting disk

Medtronic Boston Scientific

Bovine jugular valve mounted on platinum-iridium stent Bovine pericardium leaflets mounted on stainless steel or cobalt chromium alloy (SAPIEN XT) Porcine pericardium leaflets mounted on self-expanding nitinol frame Bovine pericardial, self-expanding nitinol stent

Cryolife Medtronic

Tissue engineered decellularized allograft heart valve Valved conduit of bovine jugular vein

Used for transcatheter valve-in-valve implantation for failed surgical bioprosthetic valves

620

though in Europe it has also been used in patients with tetralogy of Fallot and a right ventricular outflow tract patch (using pre-stenting techniques) [68]. It has also been used in other positions such as failed AV valve bioprostheses (also known as “valve-in-valve” replacement) [67, 69, 70], native aortic valve replacement [69], and in the branch pulmonary arteries [71]. For transcatheter aortic valve replacement/ implantation (also known as TAVR, or TAVI), there are two major devices currently available. The Edwards SAPIEN valve contains bovine pericardial leaflets sewn inside a stainless steel or cobalt chromium alloy frame. The inflow of the frame is covered with fabric to provide an annulus seal (Fig. 19.11c). The valve is positioned through a sheath (22– 24F for the SAPIEN, 16–19F for the SAPIEN XT) either from the femoral artery, ascending aorta, or through the left ventricular apex (the latter two methods utilizing a hybrid surgical approach). Once positioned, the frame and valve are balloon expanded within the diseased native aortic valve, displacing the native leaflets. Rapid ventricular pacing is performed during implantation to reduce cardiac contraction during valve implantation [72]. This valve is also used for valve-in-valve replacement (mitral, tricuspid), and is undergoing trials for use in transcatheter pulmonary valve replacement (similar to the Melody valve) [67, 73]. See Chap. 13 for an example of TAVR using a SAPIEN valve. The other major valve for TAVR/TAVI is the Medtronic Evolut R and Evolut Pro systems. These valves are composed of porcine pericardial leaflets mounted in a self-expanding nitinol frame. They are  delivered within a 14 or 16  F sheath, introduced percutaneously via femoral or subclavian artery access. Rarely, direct aortic access is utilized for delivery of the device. Once the sheathed device is located in the desired position, the device expands (and becomes deployed) by retraction of the sheath. Deployment does not require rapid ventricular pacing. To date, it has limited utility for valvein-­valve therapy. It should be noted that research and development in THVs continues at a very rapid pace, and for all the dif-

a

Fig. 19.13  Prosthetic mitral valve (bileaflet tilting disk), midesophageal  mitral commissural view, transducer angle 69°. The transducer angle is rotated until both leaflets are profiled and open symmetrically

P.-N. Jone and A. Younoszai

ferent cardiac valves; in the near future one can expect to see a number of new valves in various stages of clinical trials [74, 75].

 chocardiographic Evaluation of Prosthetic E Valves Echocardiography is important in the evaluation of these valves before and after surgery, or during transcatheter interventions [52, 76]. Postoperative evaluation of the prosthetic valve includes assessment of function of the valve and anatomic appearance of the newly implanted valve. A comprehensive TEE assessment of prosthetic valve includes careful 2D imaging with color and spectral Doppler evaluation of flow across the valve. The prosthetic valve should be examined from multiple views, with emphasis on leaflet motion, appearance of the sewing ring, and presence of any abnormal echo density that might be attached to the prothesis. The valve must be well-seated, without excessive movement, otherwise dehiscence must be suspected [52]. Then the valve should be interrogated with color and spectral Doppler for possible paravalvular leaks, stenosis, or abnormal flow. However, it is important to remember that the intraoperative setting provides unique challenges for valvar assessment due to physiologic alterations from changing preload/afterload, inotropic support, open sternum, positive pressure ventilation, and general anesthesia (also discussed in Chap. 18— Intraoperative and Postoperative Evaluation). The examination of the mechanical valve is different from a native valve, as increased spectral Doppler velocities are expected, and these will vary depending on the type of mechanical valve one is interrogating [52, 77, 78]. The mechanical bileaflet tilting disk valve (St. Jude valve) has one central orifice with two side orifices to allow for forward flow when it is open [52, 77] (Fig. 19.13a; Video 19.9). When it is closed, there are two small regurgitant (“washing”) jets at the pivot points of the valve, angled centrally

b

in diastole (a) and systole (b). There is the usual color flow Doppler profile across the valve. LA left ventricle, LV left ventricle

19  Other Applications, Including the Critical Care Setting

621

Fig. 19.14  Prosthetic mitral valve with a frozen leaflet (arrow), causing stenosis. Midesophageal four-chamber view, transducer angle 0°. LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

a

b

Fig. 19.15  Concentric pannus formation (arrows) above the mitral valve prosthesis (a), causing significant supravalvar narrowing, seen during diastole (b). Midesophageal view, transducer angle 58°. LA left ventricle, LV left ventricle

(Figs.  19.9, 19.13b) [79]. These small regurgitant jets are intended to prevent thrombus formation [79]. Abnormalities of the valve leaflet motion, vegetations, pannus formation, thrombus, paravalvular leaks, and paravalvular dehiscence can be seen well by TEE (Figs. 19.14, 19.15, 19.16, Videos 19.10, 19.11, 19.12) [79, 80]. Evaluating a mechanical aortic valve starts from the midesophageal plane, using a transducer angle between 0–120°. At 30°–40°, the long axis view of the valve can be evaluated with examination of the asymmetry of the valve leaflet position/motion and search for any ­paravalvular leaks. There can be acoustic shadowing from the midesophageal views, and this could necessitate evaluation from other windows. From the transgastric and deep transgastric views, the subaortic region can be evaluated and the valve motion can be visualized to assess for valvar regurgitation from color flow  and spectral Doppler (Fig.  19.17, Video 19.13) [79]. These views avoid the shadowing artifacts

that occurs in the midesophageal views. When evaluating atrioventricular mechanical valves, the midesophageal views from 0°–90° provide excellent visualization of the prothesis leaflets and leaflet motion from an edge-on view. Restricted leaflet motion and pannus formation can be well seen from these views. Chordal tissue and papillary muscles that are left in place after mechanical valve placement should not be confused with thrombus formation. Evaluation of biologic prosthetic valves (stented or stentless) have less acoustic shadowing compared to the mechanical valves (Fig.  19.11). The stented valves have struts that are easily seen by echocardiography and the valve leaflets are thin. Stentless valves such as homografts, xenografts, and autografts are similar to native valves when imaged by TEE. Biologic prosthetic valves can be evaluated by 2D/3D imaging, color and spectral Doppler similar to native valves [81]. In the operating room, TEE is frequently used during

622

Fig. 19.16  Paravalvar regurgitation in a child who underwent mitral valve replacement with a mechanical bileaflet prosthesis (previous history of atrioventricular septal defect repair). Image obtained from a ­midesophageal four-chamber view (transducer angle 0°). The prosthesis

a

P.-N. Jone and A. Younoszai

was too large for the annulus and required insertion at an angle, which resulted both in a large area of paravalvular regurgitation (arrow) as well as a very small effective orifice (asterisk). LA left atrium, LV left ventricle, PrMV prosthetic mitral valve, RA right atrium, RV right ventricle

b

Fig. 19.17  Prosthetic aortic valve (bileaflet tilting disk) viewed from deep transgastric position, transducer angle 96°. The transducer angle has been rotated until both leaflets are profiled and symmetric leaflet motion is noted in diastole (a) and systole (b). The prosthetic valve

position is marked by the arrow. This transducer position affords a good view of leaflet motion and flow across the valve, and also provides an excellent angle for spectral Doppler evaluation. Ao ascending aorta, LV left ventricle, PA pulmonary artery, RV right ventricle

surgery for valve replacement. In the critical care setting, if the patient is hemodynamically unstable with poor acoustic windows, then TEE is used to evaluate stenosis or regurgitation. The flow velocities through these valves immediately after the operation are used for comparison with later studies. Biologic prosthetic valves can become stenotic from calcification, thrombus formation or vegetation from infective endocarditis (Fig. 19.18, Videos 19.14, 19.15, 19.16).

stenosis or regurgitation (see Chap. 9—Mitral and tricuspid valve evaluation and Chap. 13—Outflow tract anomalies) [82, 83]. However, a few general comments are worth noting. Prosthetic valve regurgitation is primarily assessed with Doppler evaluation, mainly using color flow techniques, though spectral Doppler evaluation is helpful as well. It is important to differentiate between “normal” and pathologic prosthetic valve regurgitation. A mild degree of regurgitation is normally seen in virtually all mechanical valves (Fig. 19.9); as noted above, this can be seen in the form of the “washing” jets seen with bileaflet valves (Fig.  19.13b, Video 19.9). Minor regurgitant jets are also seen with biologic valves, including THVs. Pathologic regurgitation— characterized by one or more prominent areas of color flow Doppler regurgitation—can be either central or paravalvu-

Doppler Evaluation of Prosthetic Valves For Doppler evaluation of prosthetic valves, the principles and techniques of valve interrogation and recording of flow velocity are similar to those used for evaluating native valve

19  Other Applications, Including the Critical Care Setting

623

Fig. 19.18  Vegetation and thrombus formation in a bioprosthetic aortic valve using 2D/3D imaging. The patient presented with severe aortic valve stenosis related to infective endocarditis, with associated thrombus formation

lar (outside the valve sewing ring). Most pathologic central regurgitation is seen in biologic valves, but paravalvular regurgitation can be seen with both biologic and mechanical valves. The latter is seen as jets outside of the sewing ring of the prosthesis (Fig. 19.16, Video 19.12). It is not uncommon to see a small amount of paravalvular regurgitation immediately valve implantation (especially in THVs, see Fig.  19.11c). The degree of regurgitation can be estimated using the methods for quantification of native valvular regurgitation [82], although these can be more challenging with the shadowing and reverberations caused by the prosthetic valves (particularly mechanical valves). Commonly used parameters for semilunar valves include color flow Doppler jet width, vena contracta, pressure half-time, and diastolic flow reversal in the distal great artery; for AV valves, parameters include vena contracta, color flow Doppler jet area, as well as reversal of flow in the pulmonary or systemic veins for AV valves. A discussion of this evaluation is given in Chaps. 9 and 13. Regardless of valve type and position, when pathologic regurgitation is suspected, a careful evaluation must be made as to possible etiology. This includes location of the regurgitation (central vs. paravalvular), and possible mechanism or regurgitation (leaflet dysfunction, improper valve size/geometric mismatch, valve dehiscence, etc.). When evaluating antegrade flow across prosthetic valves, it is important to remember that the flow characteristics and velocities across prosthetic valves (particularly mechanical valves) will often differ from comparably sized native valves. In general, the spectral Doppler velocities across these valves tend to be higher. As mentioned above, several studies have presented expected Doppler velocities, gradients and effective orifice area for a wide range of biologic

and mechanical aortic and mitral valves [62, 84, 85]. Tables 19.4a and 19.4b show representative data abstracted from one of these studies [84] for several common prosthetic aortic and mitral valves. It should be noted that the labeled valve “size” (e.g. 21, 23 mm) represents the outer valve diameter in millimeters as given by the manufacturer. However, this diameter by itself is not useful, because the flow characteristics and cross-­sectional area between two identically sized valves might be completely different. Hence the effective orifice area (EOA) presented in these tables represents a better parameter for valve comparisons and overall prosthetic valve evaluation; it is an important parameter utilized in adult patients for clinical prosthetic valve assessment. The EOA is analogous to valve orifice area for a native valve, and is calculated in the same manner by the continuity equation (Chap. 1): • EOA = Stroke volume/VTIPrV • VTIPrV = Velocity time integral (VTI) through the prosthesis, measured by continuous wave Doppler • Stroke volume = VTI of the left ventricular outflow tract (by pulsed wave Doppler) multiplied by the left ventricular outflow tract cross sectional area (with prosthetic mitral valves, the calculated stroke volume is valid assuming no significant aortic regurgitation exists). The EOA is generally a better index of valve function than gradient alone, because it is will not vary with different flow states. An important concept for prosthetic valves is that the EOA must be appropriate for the flow requirements of the individual, otherwise patient-prosthetic mismatch (PPM) occurs. PPM is a term used to describe the clinical situation

624

P.-N. Jone and A. Younoszai

Table 19.4a  Doppler parameters across prosthetic aortic valves

Valve Stented bioprosthesis Hancock II (porcine)

Mosaic (porcine)

Carpentier-­Edwards (pericardial)

Mitroflow (pericardial)

Stentless bioprosthesis Medtronic Freestyle

St Jude Toronto SPV

Mechanical Medtronic-­Hall

Carbomedics (bileaflet)

St Jude (bileaflet)

Size (mm) 21 23 25 27 29 21 23 25 27 29 19 21 23 25 27 29 19 21 23 25 27 19 21 23 25 27 21 23 25 27 29 20 21 23 25 27 29 17 19 21 23 25 27 29 19 21 23 25 27 29 31

Effective orifice Peak gradient (mm Hg) Mean gradient (mm Hg) Peak velocity (m/s) area (cm2) 20 ± 0.4 24.7 ± 5.7 20 ± 2 14 ± 3 15 ± 3

14.8 ± 4.1 16.6 ± 6.9 10.7 ± 3

32.1 ± 3.4 25.7 ± 9.9 21.7 ± 8.6 16.5 ± 5.4 19.2 ± 0 17.6 ± 0 18.7 ± 5.1 20.2 14.0 ± 4.9 17 ± 11.3 13 ± 3

12.4 ± 7.3 12.5 ± 7.4 10.1 ± 5.1 9.0 9.0 24.2 ± 8.6 20.3 ± 9.1 13.0 ± 5.3 9.0 ± 2.3 5.6 11.6 10.3 ± 3 15.4 7.6 ± 3.4 10.8 ± 6.5 6.6 ± 1.7

18.6 ± 11.8 13.6 ± 7.3 12.2 ± 5.8 10 ± 4.6 7.9 ± 4.2

13.0 8 ± 2.6 7.2 ± 2.5 5.4 ± 1.5 4.7 ± 1.6 7.6 ± 4.4 7.1 ± 4.3 6.2 ± 3.1 4.8 ± 2.3 3.9 ± 2.2

34.4 ± 13.1 26.9 ± 10.5 26.9 ± 8.9 17.1 ± 7.0 18.7 ± 9.7

17.1 ± 5.3 14.1 ± 5.9 13.5 ± 4.8 9.5 ± 4.3 8.7 ± 5.6

33.4 ± 13.2 33.3 ± 11.2 26.3 ± 10.3 24.6 ± 6.9 20.3 ± 8.7 19.1 ± 7.0 12.5 ± 4.7 35.2 ± 11.2 28.3 ± 9.9 25.3 ± 7.9 22.6 ± 7.7 19.9 ± 7.6 17.7 ± 6.4 16.0

20.1 ± 7.1 11.6 ± 5.1 12.7 ± 4.3 11.3 ± 3.8 9.3 ± 4.7 8.4 ± 2.8 5.8 ± 3.2 19 ± 6.2 15.8 ± 5.7 13.8 ± 5.3 12.7 ± 5.1 11.2 ± 4.8 9.9 ± 2.9 10 ± 6

1.23 ± 0.3 1.39 ± 0.2 1.47 ± 0.2 1.55 ± 0.2 1.6 ± 0.2 1.6 ± 0.7 2.1 ± 0.8 2.1 ± 1.6 1.8 ± 0.4 2.0 ± 0.4 2.8 ± 0.1 2.6 ± 0.4 2.3 ± 0.5 2.0 ± 0.3 1.6 2.1 2.3 1.9 ± 0.3 2 ± 0.7 1.8 ± 0.2

1.2 ± 0.3 1.5 ± 0.4 1.8 ± 0.3 2.1 ± 0.4 2.2 ± 0.4 1.1 ± 0.1 1.3 ± 0.1 1.5 ± 0.2 1.8 ± 0.2

1.6 ± 0.3 1.9 ± 0.5 2.0 ± 0.4 2.5 ± 0.5 1.2 ± 0.7 1.6 ± 0.8 1.6 ± 0.4 2 ± 0.4 2.4 ± 0.7 2.9 ± 0.4 2.4 ± 0.4 2.4 ± 0.6 2.3 ± 0.5 2.1 ± 0.5 1.6 — 3.1 ± 0.4 2.6 ± 0.5 2.4 ± 0.4 2.3 ± 0.3 2.2 ± 0.4 1.9 ± 0.3 2.9 ± 0.5 2.6 ± 0.5 2.6 ± 0.4 2.4 ± 0.5 2.2 ± 0.4 2 ± 0.1 2.1 ± 0.6

1.21 ± 0.45 1.08 ± 0.17 1.36 ± 0.39 1.9 ± 0.47 1.9 ± 0.16 1.02 ± 0.2 1.25 ± 0.4 1.42 ± 0.4 1.69 ± 0.3 2.04 ± 0.4 2.55 ± 0.3 2.63 ± 0.4 1.01 ± 0.2 1.33 ± 0.3 1.6 ± 0.4 1.93 ± 0.45 2.35 ± 0.6 2.81 ± 0.6 3.08 ± 1.1

(Continued)

19  Other Applications, Including the Critical Care Setting

625

On-X (bileaflet)

19 21 23 25 27-­29

21.3 ± 10.8 16.4 ± 5.9 15.9 ± 6.4 16.5 ± 10.2 11.4 ± 4.6

11.8 ± 3.4 9.9 ± 3.6 8.5 ± 3.3 9 ± 5.3 5.6 ± 2.7

— — — — —

1.5 ± 0.2 1.7 ± 0.4 2.0 ± 0.6 2.4 ± 0.8 3.2 ± 0.6

Starr-­Edwards (Ball and Cage)

21 23 24 26 27 29

29 32.6 ± 12.8 34.1 ± 10.3 31.8 ± 9.0 30.8 ± 6.3 29 ± 9.3

22 ± 8.8 22 ± 7.5 19.7 ± 6.1 18.5 ± 3.7 16.3 ± 5.5

4 ± 0 3.5 ± 0.5 3.4 ± 0.5 3.2 ± 0.4

1.0 1.1 1.8

Table abstracted from Rosenhek R, et al. Normal values for Doppler echocardiographic assessment of heart valve prostheses. J Am Soc Echocardiogr 2003;16:1116-27. With permission from Elsevier Table 19.4b  Doppler parameters across prosthetic mitral valves Peak gradient Valve Size (mm) (mm Hg) Stented biologic Hancock II (porcine) 27 29 31 33 Carpentier-Edwards (pericardial) 27 29 31 33 Mitroflow (pericardial) 25 27 29 31 Mechanical Carbomedics (bileaflet) 23 25 10.3 ± 2.3 27 8.8 ± 3.5 29 8.8 ± 2.9 31 8.9 ± 2.3 33 8.8 ± 2.2 St Jude (bileaflet) 23 25 27 11 ± 4 29 10 ± 3 31 12 ± 6 On-X (bileaflet) 25 11.5 ± 3.2 27-29 10.3 ± 4.5 31-33 9.8 ± 3.8 Starr-Edwards (Ball and Cage) 26 28 30 12.2 ± 4.6 32 11.5 ± 4.2 34

Mean gradient (mm Hg)

Peak velocity (m/s)

Pressure half-time (ms)

Effective orifice area (cm2) 2.2 ± 0.14 2.8 ± 0.11 2.8 ± 0.1 3.2 ± 0.2

3.6 5.3 ± 3.4 4 ± 0.8 1.0 6.9 3.1 ± 0.9 3.5 ± 1.7 3.9 ± 0.8

3.6 ± 0.6 3.5 ± 1.0 3.4 ± 1.0 3.3 ± 0.9 4.8 ± 2.5 4 2.5 ± 1 5 ± 1.8 4.2 ± 1.8 4.5 ± 2.2 5.3 ± 2.1 4.5 ± 1.6 4.8 ± 2.4 10 7 ± 2.8 7 ± 2.5 5.1 ± 2.5 5

1.6 1.7 ± 0.3 1.5 ± 0.1 0.8 2.0 2.5 1.4 ± 0.3 1.3 ± 0.3

90 90 ± 20 102 ± 21 91 ± 22

1.9 ± 0.1 1.3 ± 0.1 1.6 ± 0.3 1.5 ± 0.3 1.6 ± 0.3 1.5 ± 0.2 1.5 1.3 ± 1.2 1.6 ± 0.3 1.6 ± 0.3 1.6 ± 0.3

126 ± 7 93 ± 8 89 ± 20 88 ± 17 92 ± 24 93 ± 12 160 75 ± 4 75 ± 10 85 ± 10 74 ± 13

1.7 ± 0.3 1.7 ± 0.3

125 ± 25 110 ± 25

2.9 ± 0.8 2.9 ± 0.8 2.3 ± 0.4 2.8 ± 1.1 1.0 1.4 ± 0.2 1.7 ± 0.2 1.8 ± 0.2 2.0 ± 0.3 1.9 ± 1.1 2.2 ± 0.5 2.5 ± 1.1

1.7 ± 0.4 2 ± 0.4

Table abstracted from Rosenhek R, et al. Normal values for Doppler echocardiographic assessment of heart valve prostheses. J Am Soc Echocardiogr 2003;16:1116-27. With permission from Elsevier

when the EOA of a prosthetic valve is too small in relation to a patient’s body size, resulting in abnormally high postoperative gradients [62, 86]. Studies in adults have shown that aortic PPM is associated with worsening symptoms and

impaired exercise capacity, as well as adverse cardiac events and long-term mortality [87–90]; mitral PPM is associated with persisting pulmonary hypertension and increased CHF as well as reduced survival [91]. When indexed to body sur-

626 Table 19.5  Threshold values of indexed prosthetic valve effective orifice area (EOA) for the identification and quantification of prosthesis-­ patient mismatch Mild or not clinically significant Moderate Severe cm2/m2 cm2/m2 cm2/m2 Aortic position >0.85 (0.8–0.9) ≤0.85 ≤0.65 (0.8–0.9) (0.6–0.7) Mitral position >1.2 (1.2–1.3) ≤1.2 (1.2–1.3) ≤0.9 (0.9) Numbers in parentheses represent the range of threshold values that have been used in the literature From Pibarot and Dumesnil, Prosthetic Heart Valves: Selection of the Optimal Prosthesis and Long-Term Management. Circulation 2009; 119(7):1034-1048. Used with permission of Walters-Kluwer

face area, the EOA is the only parameter found to be consistently related to postoperative gradients and/or adverse clinical outcomes [92–94]. Table 19.5 shows threshold values for indexed EOA generally used to identify and quantify the severity of PPM in adults [62]. As noted above, the information from Tables 19.4a and 19.4b are derived from studies in which data were compiled from  a number of adult studies. The tables are voluminous and comprehensive, and the reader is referred to these for further reference regarding other prosthetic valves. Nonetheless, from these data, some simplified general guidelines can be formulated to assist in the assessment of possible prosthetic aortic and mitral valve stenosis, and these are summarized by Zoghbi et al. [85] and presented in Table 19.5. These guidelines also utilize parameters such as Doppler velocity index (DVI) for prosthetic aortic valves, which is the ratio of velocities across the left ventricular outflow tract compared to the velocity across the prosthetic aortic valve, and the inverse relationship for mitral valves, the ratio of the prosthetic mitral valve VTI compared to the VTI across the left ventricular outflow tract. These dimensionless ratios—derived from the continuity equation—are much less dependent upon varying flow states. It should be noted that comparable data for prosthetic pulmonary and tricuspid valves is lacking, particularly regarding normal and abnormal EOAs and DVI/VTI.  Therefore more general guidelines, also presented by Zoghbi et al., have been presented for these valves as follows [85]: • Findings suspicious for prosthetic pulmonary stenosis –– Cusp or leaflet thickening or immobility. –– Narrowing of forward color map. –– Peak velocity through the prosthesis >3 m/s or > 2 m/s through a homograft (suspicious but not diagnostic of stenosis). –– Increase in peak velocity on serial studies (more reliable parameter).

P.-N. Jone and A. Younoszai

–– Impaired right ventricular function or elevated right ventricular systolic pressure. • Findings suspicious for tricuspid valve stenosis –– Peak velocity > 1.7 m/s (because of respiratory variation, average ≥ 5 cycles). –– Mean gradient ≥6 mm Hg (may be increased if there is valvular regurgitation). –– Pressure half-time ≥ 230 ms. –– Narrow inflow color map. –– Nonspecific signs such as enlarged right atrium and engorged inferior vena cava. In general, an integrated approach, using a combination of the criteria discussed above, works best when evaluating forward flow across any prosthetic valve. For pediatric patients, there is a notable paucity of available published information regarding normal velocities and EOAs across prosthetic valves, particularly the smaller mitral and aortic valves. Much of the information used in this age group originates from adult data. Fortunately many of the same principles can still be applied, though comparable values to those obtained in adults are still lacking, and it is unclear whether certain parameters are equivalent in this population. For example, one study evaluating St. Jude and Carbomedics mitral prostheses in children found that peak early Doppler velocity—not EOA—correlated best with the manufacturer’s geometric valve orifice area, and also pulmonary artery wedge pressure [95]. The use of the DVI and VTI ratios has not been established in the pediatric population. Also, PPM has not been evaluated closely in children, though it  would seem evident that this particular concept has direct relevance in the pediatric population because of growth considerations. While the goal for valve replacement in children is to implant the largest possible prosthesis, patient growth will inevitably lead to some degree of PPM, even with a n­ ormally functioning prosthesis [85]. As noted above, the most widely accepted and validated parameter for identifying PPM in adult patients is the indexed EOA, and Table  19.6 shows threshold values for indexed EOA generally used to identify and quantify the severity of PPM in adults [62]. This table might also serve as useful guide in children, although the applicability of these values in pediatrics has yet to be fully determined. For catheter-based implantable heart valves, the role of TEE will vary based upon the type of THV and its position. For TAVR (both SAPIEN and Evolut valves), TEE plays an integral role in all three phases of the procedure: pre-­ procedural assessment of morphology and annular measurements, intraprocedural monitoring of all phases of the valve implantation (including guide wire and device positioning and valve deployment), and post-deployment assessment of possible paravalvar device leaks as well as ventricular function,

19  Other Applications, Including the Critical Care Setting

627

Table 19.6  Doppler parameters across prosthetic aortic and mitral valves Parameter Aortic mechanical, stented valves  Peak velocity (m/s)  Mean gradient (mm Hg)  DVI  Effective Orifice Area (cm2)  Contour of jet velocity through prosthetic aortic valve  Acceleration time (ms) Other pertinent findings: left ventricular size, function, hypertrophy Mitral valve prostheses  Peak velocity (m/s)  Mean gradient (mm Hg)  VTI (PrMV)/VTI (LVOT)  Effective Orifice Area (cm2)  Pressure half-time (ms) Other pertinent findings: left ventricular size and function, left atrial size, right ventricular size and function, estimation of pulmonary artery pressure

Normal

Possible stenosis Suggests significant stenosis

35 38  °C, and high risk-cardiac conditions are all minor Duke criteria.

630

P.-N. Jone and A. Younoszai

2. Of the following, which is the most common causative organism for infective endocarditis in children? a. Staphylococcus aureus b. Neisseria meningitidis c. Streptococcus pneumoniae d. Hemophilus influenzae



Answer: a Explanation: Staphylococcus aureus and Viridans streptococci are by far the dominant organisms causing endocarditis in children. The other organisms mentioned, while responsible for other childhood illnesses, do not have a high association with infective endocarditis.

Answer: b Explanation: When a mechanical valve is closed, there are normally characteristic regurgitant (“washing”) jets that can be seen at the pivot points of the valve, angled centrally. These are a normal part of the valve design. On the other hand, it is abnormal to see a paravalvar regurgitant jet outside the sewing ring of the valve. The other two choices are accurate: acoustic shadowing can interfere with visualization of the valve, and spectral Doppler velocities across the mechanical valve tend to be higher than those of a native valve.

3. All of the following are known echocardiographic manifestations of IE except: a. Abscesses b. Flail valve leaflets c. Dehiscence of a prosthetic valve d. Appearance of left ventricular noncompaction Answer: d Explanation. From an echocardiographic standpoint, IE can present in a number of different ways, including oscillating masses adherent to the valves (vegetations), abscesses, fistulous tracks, valve disruption (flail leaflets), and dehiscence of a prosthetic valve. Left ventricular compaction is an echocardiographic appearance of abnormal left ventricular myocardial anatomy (and sometimes function), and it is not a known manifestation of IE. 4. Which of the following predisposes to thrombus formation in the left atrial appendage: a. Aortic regurgitation b. Mitral regurgitation c. Atrial fibrillation d. Ebstein’s anomaly of the tricuspid valve Answer: c Explanation: Those patients with discoordinated atrial contraction, resulting in stasis of atrial blood flow, can be predisposed to development of thrombus in the left atrial appendage. This is seen in patients who have atrial fibrillation/flutter. The other three choices still have coordinated atrial contraction, although if atrial dilation form mitral stenosis/mitral regurgitation is severe enough, atrial fibrillation could occur. 5. All of the following regarding the echocardiographic evaluation of a mechanical bileaflet tilting disc valves are true except: a. Acoustic shadowing can interfere with visualization of the valve

b. It is abnormal to see any systolic regurgitant jets with a mechanical valve c. Spectral Doppler velocities will be different than a native valve d. It is abnormal to see a paravalvar regurgitant jet outside the sewing ring of the valve

References 1. Baltimore RS, Gewitz M, Baddour LM, Beerman LB, Jackson MA, Lockhart PB, et  al. Infective endocarditis in childhood: 2015 update: a scientific statement from the American Heart Association. Circulation. 2015;132(15):1487–515. 2. Bayer AS, Bolger AF, Taubert KA, Wilson W, Steckelberg J, Karchmer AW, et  al. Diagnosis and management of infective endocarditis and its complications. Circulation. 1998;98(25):2936–48. 3. Ferrieri P, Gewitz MH, Gerber MA, Newburger JW, Dajani AS, Shulman ST, et  al. Unique features of infective endocarditis in childhood. Circulation. 2002;105(17):2115–26. 4. Elder RW, Baltimore RS. The changing epidemiology of pediatric endocarditis. Infect Dis Clin N Am. 2015;29(3):513–24. 5. Saiman L, Prince A, Gersony WM. Pediatric infective endocarditis in the modern era. J Pediatr. 1993;122(6):847–53. 6. Morris CD, Reller MD, Menashe VD.  Thirty-year incidence of infective endocarditis after surgery for congenital heart defect. JAMA. 1998;279(8):599–603. 7. Martin JM, Neches WH, Wald ER.  Infective endocarditis: 35 years of experience at a children’s hospital. Clin Infect Dis. 1997;24(4):669–75. 8. Lin YT, Hsieh KS, Chen YS, Huang IF, Cheng MF.  Infective endocarditis in children without underlying heart disease. J Microbiol Immunol Infect. 2013;46(2):121–8. 9. Stockheim JA, Chadwick EG, Kessler S, Amer M, Abdel-Haq N, Dajani AS, et al. Are the Duke criteria superior to the Beth Israel criteria for the diagnosis of infective endocarditis in children? Clin Infect Dis. 1998;27(6):1451–6. 10. Li JS, Sexton DJ, Mick N, Nettles R, Fowler VG Jr, Ryan T, et al. Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis. Clin Infect Dis. 2000;30(4):633–8. 11. Roe MT, Abramson MA, Li J, Heinle SK, Kisslo J, Corey GR, et al. Clinical information determines the impact of transesophageal echocardiography on the diagnosis of infective endocarditis by the duke criteria. Am Heart J. 2000;139(6):945–51. 12. Rohmann S, Erbel R, Mohr-Kahaly S, Meyer J.  Use of transoesophageal echocardiography in the diagnosis of abscess in infective endocarditis. Eur Heart J. 1995;16(Suppl B):54–62. 13. Rohmann S, Erbel R, Gorge G, Makowski T, Mohr-Kahaly S, Nixdorff U, et al. Clinical relevance of vegetation localization by

19  Other Applications, Including the Critical Care Setting transoesophageal echocardiography in infective endocarditis. Eur Heart J. 1992;13(4):446–52. 14. Rohmann S, Seifert T, Erbel R, Jakob H, Mohr-Kahaly S, Makowski T, et al. Identification of abscess formation in native-­ valve infective endocarditis using transesophageal echocardiography: implications for surgical treatment. Thorac Cardiovasc Surg. 1991;39(5):273–80. 15. Erbel R, Rohmann S, Drexler M, Mohr-Kahaly S, Gerharz CD, Iversen S, et al. Improved diagnostic value of echocardiography in patients with infective endocarditis by transoesophageal approach. A prospective study. Eur Heart J. 1988;9(1):43–53. 16. Klodas E, Edwards WD, Khandheria BK. Use of transesophageal echocardiography for improving detection of valvular vegetations in subacute bacterial endocarditis. J Am Soc Echocardiogr. 1989;2(6):386–9. 17. Daniel WG, Mugge A, Martin RP, Lindert O, Hausmann D, Nonnast-Daniel B, et  al. Improvement in the diagnosis of abscesses associated with endocarditis by transesophageal echocardiography. N Engl J Med. 1991;324(12):795–800. 18. Mugge A, Daniel WG, Frank G, Lichtlen PR. Echocardiography in infective endocarditis: reassessment of prognostic implications of vegetation size determined by the transthoracic and the transesophageal approach. J Am Coll Cardiol. 1989;14(3):631–8. 19. Reynolds HR, Jagen MA, Tunick PA, Kronzon I.  Sensitivity of transthoracic versus transesophageal echocardiography for the detection of native valve vegetations in the modern era. J Am Soc Echocardiogr. 2003;16(1):67–70. 20. Daniel WG, Mugge A, Grote J, Hausmann D, Nikutta P, Laas J, et al. Comparison of transthoracic and transesophageal echocardiography for detection of abnormalities of prosthetic and bioprosthetic valves in the mitral and aortic positions. Am J Cardiol. 1993;71(2):210–5. 21. Humpl T, McCrindle BW, Smallhorn JF.  The relative roles of transthoracic compared with transesophageal echocardiography in children with suspected infective endocarditis. J Am Coll Cardiol. 2003;41(11):2068–71. 22. Penk JS, Webb CL, Shulman ST, Anderson EJ. Echocardiography in pediatric infective endocarditis. Pediatr Infect Dis J. 2011;30(12):1109–11. 23. Durack DT, Beeson PB.  Experimental bacterial endocarditis. I.  Colonization of a sterile vegetation. Br J Exp Pathol. 1972;53(1):44–9. 24. Durack DT, Beeson PB.  Experimental bacterial endocarditis. II.  Survival of a bacteria in endocardial vegetations. Br J Exp Pathol. 1972;53(1):50–3. 25. Karchmer AW. Infective endocarditis. In: Bonow RO, Mann DL, Zipes DP, Libby P, editors. Braunwald’s heart disease: a textbook of cardiovascular medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2012. p. 1540–60. 26. Zoghbi WA, Adams D, Bonow RO, Enriquez-Sarano M, Foster E, Grayburn PA, et al. Recommendations for noninvasive evaluation of native valvular regurgitation: a report from the American Society of Echocardiography Developed in Collaboration with the Society for Cardiovascular Magnetic Resonance. J Am Soc Echocardiogr. 2017;30(4):303–71. 27. Baddour LM, Wilson WR, Bayer AS, Fowler VG Jr, Tleyjeh IM, Rybak MJ, et al. Infective endocarditis in adults: diagnosis, antimicrobial therapy, and management of complications: a scientific statement for healthcare professionals from the American Heart Association. Circulation. 2015;132(15):1435–86. 28. Shaffer EM, Snider AR, Beekman RH, Behrendt DM, Peschiera AW. Sinus of Valsalva aneurysm complicating bacterial endocarditis in an infant: diagnosis with two-dimensional and Doppler echocardiography. J Am Coll Cardiol. 1987;9(3):588–91. 29. Anguera I, Miro JM, Vilacosta I, Almirante B, Anguita M, Munoz P, et  al. Aorto-cavitary fistulous tract formation in infective endocarditis: clinical and echocardiographic fea-

631 tures of 76 cases and risk factors for mortality. Eur Heart J. 2005;26(3):288–97. 30. Anguera I, Miro JM, San Roman JA, de Alarcon A, Anguita M, Almirante B, et  al. Periannular complications in infective endocarditis involving prosthetic aortic valves. Am J Cardiol. 2006;98(9):1261–8. 31. Sievers HH, Stierle U, Charitos EI, Hanke T, Misfeld M, Matthias Bechtel JF, et  al. Major adverse cardiac and cerebrovascular events after the Ross procedure: a report from the German-Dutch Ross Registry. Circulation. 2010;122(11 Suppl):S216–23. 32. Hasbun R, Vikram HR, Barakat LA, Buenconsejo J, Quagliarello VJ. Complicated left-sided native valve endocarditis in adults: risk classification for mortality. JAMA. 2003;289(15):1933–40. 33. Mills J, Utley J, Abbott J. Heart failure in infective endocarditis: predisposing factors, course, and treatment. Chest. 1974;66(2):151–7. 34. Ryan EW, Bolger AF. Transesophageal echocardiography (TEE) in the evaluation of infective endocarditis. In: Foster E, editor. Cardiology clinics: Transesophageal Echocardiography. Division of Cardiology, Department of Medicine, University of California, San Francisco, USA; 2000. p. 773–87. 35. Prendergast BD, Tornos P. Surgery for infective endocarditis: who and when? Circulation. 2010;121(9):1141–52. 36. Saiman L, Prince A, Gersony WM. Pediatric infective endocarditis in the modern era. J Pediatr. 1993;122(6):847–53. 37. Baddour LM, Wilson WR, Bayer AS, Fowler VGJ, Bolger AF, Levison ME, et  al. Infective endocarditis: diagnosis, antimicrobial therapy, and management of complications: a statement for healthcare professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, and the Councils on Clinical Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia, American Heart Association: endorsed by the Infectious Diseases Society of America. Circulation. 2005;111(23):e394–434. 38. Lopez JA, Ross RS, Fishbein MC, Siegel RJ. Nonbacterial thrombotic endocarditis: a review. Am Heart J. 1987;113(3):773–84. 39. Asopa S, Patel A, Khan OA, Sharma R, Ohri SK.  Non-­ bacterial thrombotic endocarditis. Eur J Cardiothorac Surg. 2007;32(5):696–701. 40. González Quintela A, Candela MJ, Vidal C, Román J, Aramburo P. Non-bacterial thrombotic endocarditis in cancer patients. Acta Cardiol. 1991;46(1):1–9. 41. Beynon RP, Bahl VK, Prendergast BD.  Infective endocarditis. BMJ. 2006;333(7563):334–9. 42. Agmon Y, Khandheria BK, Gentile F, Seward JB. Echocardiographic assessment of the left atrial appendage. J Am Coll Cardiol. 1999;34(7):1867–77. 43. Stabile G, Russo V, Rapacciuolo A, De Divitiis M, De Simone A, Solimene F, et al. Transesophageal echocardiograpy in patients with persistent atrial fibrillation undergoing electrical cardioversion on new oral anticoagulants: a multi center registry. Int J Cardiol. 2015;184:283–4. 44. de Divitiis M, Omran H, Rabahieh R, Rang B, Illien S, Schimpf R, et  al. Right atrial appendage thrombosis in atrial fibrillation: its frequency and its clinical predictors. Am J Cardiol. 1999;84(9):1023–8. 45. Ozer O, Sari I, Davutoglu V.  Right atrial appendage: forgotten part of the heart in atrial fibrillation. Clin Appl Thromb Hemost. 2010;16(2):218–20. 46. Schweizer P, Bardos P, Erbel R, Meyer J, Merx W, Messmer BJ, et  al. Detection of left atrial thrombi by echocardiography. Br Heart J. 1981;45(2):148–56. 47. Aschenberg W, Schluter M, Kremer P, Schroder E, Siglow V, Bleifeld W. Transesophageal two-dimensional echocardiography for the detection of left atrial appendage thrombus. J Am Coll Cardiol. 1986;7(1):163–6. 48. Manning WJ, Weintraub RM, Waksmonski CA, Haering JM, Rooney PS, Maslow AD, et al. Accuracy of transesophageal echo-

632 cardiography for identifying left atrial thrombi. A prospective, intraoperative study. Ann Intern Med. 1995;123(11):817–22. 49. Veinot JP, Harrity PJ, Gentile F, Khandheria BK, Bailey KR, Eickholt JT, et al. Anatomy of the normal left atrial appendage: a quantitative study of age-related changes in 500 autopsy hearts: implications for echocardiographic examination. Circulation. 1997;96(9):3112–5. 50. Karakus G, Kodali V, Inamdar V, Nanda NC, Suwanjutah T, Pothineni KR.  Comparative assessment of left atrial appendage by transesophageal and combined two- and three-­ dimensional transthoracic echocardiography. Echocardiography. 2008;25(8):918–24. 51. Werner JA, Cheitlin MD, Gross BW, Speck SM, Ivey TD. Echocardiographic appearance of the Chiari network: differentiation from right-heart pathology. Circulation. 1981;63(5):1104–9. 52. Zoghbi WA, Chambers JB, Dumesnil JG, Foster E, Gottdiener JS, Grayburn PA, et al. Recommendations for evaluation of prosthetic valves with echocardiography and doppler ultrasound: a report from the American Society of Echocardiography’s Guidelines and Standards Committee and the Task Force on Prosthetic Valves, developed in conjunction with the American College of Cardiology Cardiovascular Imaging Committee, Cardiac Imaging Committee of the American Heart Association, the European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography and the Canadian Society of Echocardiography, endorsed by the American College of Cardiology Foundation, American Heart Association, European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography, and Canadian Society of Echocardiography. J Am Soc Echocardiogr. 2009;22(9):975–1014; quiz 82–4. 53. Ross DN. Replacement of aortic and mitral valves with a pulmonary autograft. Lancet. 1967;2(7523):956–8. 54. Chambers JC, Somerville J, Stone S, Ross DN. Pulmonary autograft procedure for aortic valve disease: long-term results of the pioneer series. Circulation. 1997;96(7):2206–14. 55. Athanasiou T, Cherian A, Ross D.  The Ross II procedure: pulmonary autograft in the mitral position. Ann Thorac Surg. 2004;78(4):1489–95. 56. Protopapas AD, Athanasiou T.  Contegra conduit for reconstruction of the right ventricular outflow tract: a review of published early and mid-time results. J Cardiothorac Surg. 2008;3:62. 57. Hickey EJ, McCrindle BW, Blackstone EH, Yeh T, Pigula F, Clarke D, et al. Jugular venous valved conduit (Contegra) matches allograft performance in infant truncus arteriosus repair. Eur J Cardiothorac Surg. 2008;33(5):890–8. 58. Christenson JT, Sierra J, Colina Manzano NE, Jolou J, Beghetti M, Kalangos A. Homografts and xenografts for right ventricular outflow tract reconstruction: long-term results. Ann Thorac Surg. 2010;90(4):1287–93. 59. Dave H, Mueggler O, Comber M, Enodien B, Nikolaou G, Bauersfeld U, et al. Risk factor analysis of 170 single-institutional contegra implantations in pulmonary position. Ann Thorac Surg. 2011;91(1):195–302; discussion 202–3. 60. Prog Pediatr Cardiol. In: Hopkins RA, editor. Tissue and bio-­ engineering for congenital cardiac disease 2006. p. 137–244. 61. Aslam AK, Aslam AF, Vasavada BC, Khan IA.  Prosthetic heart valves: types and echocardiographic evaluation. Int J Cardiol. 2007;122(2):99–110. 62. Pibarot P, Dumesnil JG.  Prosthetic heart valves: selection of the optimal prosthesis and long-term management. Circulation. 2009;119(7):1034–48. 63. Oosterhof T, Hazekamp MG, Mulder BJM.  Opportunities in pulmonary valve replacement. Expert Rev Cardiovasc Ther. 2009;7(9):1117–22.

P.-N. Jone and A. Younoszai 64. Kidane AG, Burriesci G, Cornejo P, Dooley A, Sarkar S, Bonhoeffer P, et  al. Current developments and future prospects for heart valve replacement therapy. J Biomed Mater Res B Appl Biomater. 2009;88(1):290–303. 65. Bonow RO, Carabello BA, Chatterjee K, de Leon AC, Faxon DP, Freed MD, et al. 2008 Focused update incorporated into the ACC/ AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/ American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation. 2008;118(15):e523–661. 66. Waterbolk TW, Hoendermis ES, den Hamer IJ, Ebels T. Pulmonary valve replacement with a mechanical prosthesis. Promising results of 28 procedures in patients with congenital heart disease. Eur J Cardiothorac Surg. 2006;30(1):28–32. 67. Fleming GA, Hill KD, Green AS, Rhodes JF.  Percutaneous pulmonary valve replacement. Prog Pediatr Cardiol. 2012;33(2):143–50. 68. Momenah TS, El Oakley R, Al Najashi K, Khoshhal S, Al Qethamy H, Bonhoeffer P. Extended application of percutaneous pulmonary valve implantation. J Am Coll Cardiol. 2009;53(20):1859–63. 69. Hasan BS, McElhinney DB, Brown DW, Cheatham JP, Vincent JA, Hellenbrand WE, et al. Short-term performance of the transcatheter Melody valve in high-pressure hemodynamic environments in the pulmonary and systemic circulations. Circ Cardiovasc Interv. 2011;4(6):615–20. 70. Gurvitch R, Cheung A, Ye J, Wood DA, Willson AB, Toggweiler S, et al. Transcatheter valve-in-valve implantation for failed surgical bioprosthetic valves. J Am Coll Cardiol. 2011;58(21):2196–209. 71. Gillespie MJ, Dori Y, Harris MA, Sathanandam S, Glatz AC, Rome JJ.  Bilateral branch pulmonary artery melody valve implantation for treatment of complex right ventricular outflow tract dysfunction in a high-risk patient. Circ Cardiovasc Interv. 2011;4(4):e21–3. 72. Billings FT, Kodali SK, Shanewise JS.  Transcatheter aortic valve implantation: anesthetic considerations. Anesth Analg. 2009;108(5):1453–62. 73. Kenny D, Hijazi ZM, Kar S, Rhodes J, Mullen M, Makkar R, et al. Percutaneous implantation of the Edwards SAPIEN transcatheter heart valve for conduit failure in the pulmonary position: early phase 1 results from an international multicenter clinical trial. J Am Coll Cardiol. 2011;58(21):2248–56. 74. Rotman OM, Bianchi M, Ghosh RP, Kovarovic B, Bluestein D.  Principles of TAVR valve design, modelling, and testing. Expert Rev Med Devices. 2018;15(11):771–91. 75. Siddique S, Gada H, Mumtaz MA, Vora AN. Should all low-risk patients now be considered for TAVR? Operative risk, clinical, and anatomic considerations. Curr Cardiol Rep. 2019;21(12):161. 76. Mankad SV, Aldea GS, Ho NM, Mankad R, Pislaru S, Rodriguez LL, et al. Transcatheter mitral valve implantation in degenerated bioprosthetic valves. J Am Soc Echocardiogr. 2018;31(8):845–59. 77. Pibarot P, Dumesnil JG.  Prosthetic heart valves: selection of the optimal prosthesis and long-term management. Circulation. 2009;119(7):1034–48. 78. Rosenhek R, Binder T, Maurer G, Baumgartner H. Normal values for Doppler echocardiographic assessment of heart valve prostheses. J Am Soc Echocardiogr. 2003;16(11):1116–27. 79. Bach DS.  Transesophageal echocardiographic (TEE) evaluation of prosthetic valves. Cardiol Clin. 2000;18(4):751–71. 80. Aslam AK, Aslam AF, Vasavada BC, Khan IA.  Prosthetic heart valves: types and echocardiographic evaluation. Int J Cardiol. 2007;122(2):99–110.

19  Other Applications, Including the Critical Care Setting 81. Baumgartner H, Hung J, Bermejo J, Chambers JB, Evangelista A, Griffin BP, et  al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr 2009;22(1):1–23; quiz 101–2. 82. Zoghbi WA, Enriquez-Sarano M, Foster E, Grayburn PA, Kraft CD, Levine RA, et  al. Recommendations for evaluation of the severity of native valvular regurgitation with two-­dimensional and Doppler echocardiography. J Am Soc Echocardiogr. 2003;16(7):777–802. 83. Quiñones M.  Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr. 2009;22(1):1–23. 84. Rosenhek R, Binder T, Maurer G, Baumgartner H. Normal values for Doppler echocardiographic assessment of heart valve prostheses. J Am Soc Echocardiogr. 2003;16(11):1116–27. 85. Zoghbi WA, Chambers JB, Dumesnil JG, Foster E, Gottdiener JS, Grayburn PA, et al. Recommendations for evaluation of prosthetic valves with echocardiography and doppler ultrasound: a report From the American Society of Echocardiography’s Guidelines and Standards Committee and the Task Force on Prosthetic Valves, developed in conjunction with the American College of Cardiology Cardiovascular Imaging Committee, Cardiac Imaging Committee of the American Heart Association, the European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography and the Canadian Society of Echocardiography, endorsed by the American College of Cardiology Foundation, American Heart Association, European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography, and Canadian Society of Echocardiography. J Am Soc Echocardiogr. 2009;22(9):975–1014; quiz 82–4. 86. Rahimtoola SH.  The problem of valve prosthesis-patient mismatch. Circulation. 1978;58(1):20–4. 87. Pibarot P, Dumesnil JG.  Hemodynamic and clinical impact of prosthesis-patient mismatch in the aortic valve position and its prevention. J Am Coll Cardiol. 2000;36(4):1131–41. 88. Mohty D, Mohty-Echahidi D, Malouf JF, Girard SE, Schaff HV, Grill DE, et  al. Impact of prosthesis-patient mismatch on long-­term survival in patients with small St Jude Medical mechanical prostheses in the aortic position. Circulation. 2006;113(3):420–6. 89. Walther T, Rastan A, Falk V, Lehmann S, Garbade J, Funkat AK, et al. Patient prosthesis mismatch affects short- and long-term outcomes after aortic valve replacement. Eur J Cardiothorac Surg. 2006;30(1):15–9.

633 90. Rahimtoola SH.  Choice of prosthetic heart valve in adults an update. J Am Coll Cardiol. 2010;55(22):2413–26. 91. Lam B-K, Chan V, Hendry P, Ruel M, Masters R, Bedard P, et al. The impact of patient-prosthesis mismatch on late outcomes after mitral valve replacement. J Thorac Cardiovasc Surg. 2007;133(6):1464–73. 92. Blackstone EH, Cosgrove DM, Jamieson WRE, Birkmeyer NJ, Lemmer JH, Miller DC, et al. Prosthesis size and long-term survival after aortic valve replacement. J Thorac Cardiovasc Surg. 2003;126(3):783–96. 93. Koch CG, Khandwala F, Estafanous FG, Loop FD, Blackstone EH. Impact of prosthesis-patient size on functional recovery after aortic valve replacement. Circulation. 2005;111(24):3221–9. 94. Pibarot P, Dumesnil JG. Prosthesis-patient mismatch: definition, clinical impact, and prevention. Heart. 2006;92(8):1022–9. 95. Masuda M, Kado H, Tatewaki H, Shiokawa Y, Yasui H.  Late results after mitral valve replacement with bileaflet mechanical prosthesis in children: evaluation of prosthesis-patient mismatch. Ann Thorac Surg. 2004;77(3):913–7. 96. Zamorano JL, Badano LP, Bruce C, Chan K-L, Gonçalves A, Hahn RT, et al. EAE/ASE recommendations for the use of echocardiography in new transcatheter interventions for valvular heart disease. J Am Soc Echocardiogr. 2011;24(9):937–65. 97. Holmes DR, Mack MJ, Kaul S, Agnihotri A, Alexander KP, Bailey SR, et al. 2012 ACCF/AATS/SCAI/STS expert consensus document on transcatheter aortic valve replacement. J Am Coll Cardiol. 2012;59(13):1200–54. 98. Shuto T, Kondo N, Dori Y, Koomalsingh KJ, Glatz AC, Rome JJ, et  al. Percutaneous transvenous melody valve-in-ring procedure for mitral valve replacement. J Am Coll Cardiol. 2011;58(24):2475–80. 99. Kondo N, Shuto T, McGarvey JR, Koomalsingh KJ, Takebe M, Gorman RC, et  al. Melody valve-in-ring procedure for mitral valve replacement: feasibility in four annuloplasty types. Ann Thorac Surg. 2012;93(3):783–8. 100. El-Eshmawi A, Love B, Bhatt HV, Pawale A, Boateng P, Adams DH. Direct access implantation of a Melody valve in native mitral valve: a hybrid approach in the presence of extensive mitral annular calcification. Ann Thorac Surg. 2015;99(3):1085. 101. Trezzi M, Cetrano E, Iacobelli R, Carotti A.  Edwards Sapien 3 valve for mitral replacement in a child after melody valve endocarditis. Ann Thorac Surg. 2017;104(6):e429–e30. 102. Pluchinotta FR, Piekarski BL, Milani V, Kretschmar O, Burch PT, Hakami L, et al. Surgical atrioventricular valve replacement with melody valve in infants and children. Circ Cardiovasc Interv. 2018;11(11):e007145.

Applications for Non-Congenital Heart Disease in Pediatric Patients

20

Richard M. Friesen and Luciana T. Young

Abbreviations

Key Learning Objectives

2D Two-dimensional 3D Three-dimensional CHD Congenital heart disease DTG Deep transgastric ECMO Extracorporeal membrane oxygenation FAC Fractional area change IVC Inferior vena cava LV Left ventricle/left ventricular LVAD Left ventricular assist device ME Midesophageal PFO Patent foramen ovale RV Right ventricle/right ventricular SVC Superior vena cava TAPSE Tricuspid annular plane systolic excursion TEE Transesophageal echocardiography TG Transgastric TTE Transthoracic echocardiography UE Upper esophageal VA Veno-arterial VAD Ventricular assist device VV Veno-venous

• Define the applications of transesophageal echocardiography (TEE) in pediatric cardiac, lung, and liver transplantation • Recognize the various options for mechanical circulatory support available for children and young adults and discuss how TEE is utilized in their assessment • Describe the applications of TEE in the assessment of the patient with pulmonary hypertension, pulmonary embolism, or pericardial disease • Understand the utility of TEE in the evaluation of aortic dissection • Discuss the different types of pediatric cardiac tumors, review their echocardiographic appearance, and describe how TEE is utilized in their evaluation

Electronic Supplementary Material The online version of this chapter (https://doi.org/10.1007/978-­3-­030-­57193-­1_20) contains supplementary material, which is available to authorized users. R. M. Friesen Pediatric Cardiology, Children’s Hospital Colorado, Aurora, CO, USA e-mail: [email protected] L. T. Young (*) Pediatric Cardiology, Seattle Children’s Hospital, Seattle, WA, USA e-mail: [email protected]

Introduction The utility of transesophageal echocardiography (TEE) in pediatric cardiology is primarily directed at the evaluation of congenital heart disease (CHD). However, there are a number of conditions where TEE can be extremely beneficial in children and young adults with cardiovascular pathologies other than congenital malformations  of the cardiovascular system. This chapter discusses several of these conditions in which TEE can be valuable, including evaluation surrounding transplantation of solid organs such as the heart, lung, and liver, ventricular assist devices (VADs), pulmonary hypertension and embolism, pericardial diseases, aortic dissection, and cardiac tumors. Topics such as TEE assessment of cardiac thrombus, artificial valves, and guidance during catheter-based interventions are discussed in detail elsewhere in this textbook. The reader is also referred to the recent publication entitled Guidelines for the Use of Transesophageal Echocardiography to Assist with Surgical Decision-Making

© Springer Nature Switzerland AG 2021 P. C. Wong, W. C. Miller-Hance (eds.), Transesophageal Echocardiography for Pediatric and Congenital Heart Disease, https://doi.org/10.1007/978-3-030-57193-1_20

635

636

in the Operating Room: A Surgery-Based Approach: From the American Society of Echocardiography in Collaboration with the Society of Cardiovascular Anesthesiologists and the Society of Thoracic Surgeons. This comprehensive document, based on available evidence and expert opinion, offers a systematic approach to intraoperative TEE imaging in patients with most conditions discussed in this chapter. Although written primarily by adult specialists, the concepts and approaches can also be applied to the non-congenital pediatric population [1].

Solid Organ Transplantation Heart Transplantation Despite significant advances in pediatric medical, interventional, and surgical therapies over the last several decades, heart transplantation remains the standard treatment for end-­ stage heart disease in children. Major diagnostic categories in the pediatric age group meeting indications for cardiac transplantation include CHD, cardiomyopathies, and retransplantation. Echocardiography is known to play an important role throughout the care of these patients and in particular, the TEE modality as outlined below.

 valuation of Cardiac Transplant Recipients E Echocardiography is essential for diagnosis and management of children with heart failure. Accurate assessment of systolic and diastolic function, as well as ventricular chamber size and wall thickness, are important components of Class I recommendations for cardiac transplantation from the International Society for Heart and Lung Transplantation [2]. While the majority of noninvasive evaluation in potential heart transplant recipients is achieved primarily through transthoracic echocardiography (TTE), TEE can be beneficial under certain circumstances. These include during detailed evaluation of valvular function, assessment for intracardiac thrombus, or when transthoracic imaging windows are suboptimal.  creening of Cardiac Transplant Donors S Detailed echocardiographic assessment of prospective cardiac transplant donors is essential to evaluate ventricular function, both global and segmental, and exclude structural abnormalities that might preclude the procedure [3]. Since many cardiac transplant donor candidates are mechanically ventilated, poor transthoracic imaging is often a concern. An adult study reported that up to 29% of mechanically ventilated potential donors had technically inadequate TTE imaging [4]. Although this issue might be less problematic in children as compared to the adult patient, in these situations TEE may achieve improved visualization of the intracardiac anatomy and determine suitability of the organ for transplantation [5].

R. M. Friesen and L. T. Young

Intraoperative TEE Evaluation Intraoperative Monitoring and Assessment Preoperative TEE is generally not indicated during cardiac transplantation as the native heart will be explanted unless there are specific questions or issues that may impact clinical care. However, TEE can be helpful in diagnosing and managing hemodynamic instability prior to the initiation of cardiopulmonary bypass. In addition, abnormalities of cardiac position, systemic and pulmonary venous return, and arterial connections can be further delineated by TEE to aid in procurement and complex implantation. Estimation of pulmonary arterial pressure by tricuspid and/or pulmonary valve regurgitant jet velocities can be helpful in identifying patients who may have issues related to pulmonary hypertension after implantation and to plan perioperative management accordingly. Intraoperative Post-Transplant Evaluation The benefits of TEE imaging following cardiac transplantation are well recognized [6–8]. The initial intraoperative post surgical assessment should focus on the evaluation of venous and arterial anastomoses, which requires an understanding of the technique used for implantation. Most commonly a bicaval or biatrial technique is used [9]. A bicaval anastomosis consists of the donor superior vena cava (SVC) and inferior vena cava (IVC) sewn to the respective recipient caval veins. The left atrial cuff is fashioned by connecting the donor left atrium to the remnant recipient native left atrium, resulting in a dilated “hourglass” appearance as depicted by TEE usually in a midesophageal four-chamber view (ME 4-Ch; transducer angle ~0°–10°; Fig. 20.1, Video 20.1) [7]. A biatrial anastomosis technique will result in a similar cuff within the right atrium leaving the recipient’s native caval veins in place. The aortic and pulmonary arterial anastomotic sites should be interrogated for narrowing [10, 11]. This is especially vital in the recipient with a history of previous CHD (which constitutes approximately 40% of pediatric heart transplant recipients), situs abnormalities, or in those that required significant vascular reconstruction at the time of transplantation [12–14]. All anastomoses should be visualized by TEE with two-dimensional (2D) imaging, and assessed with color and spectral Doppler for potential narrowing [6, 11]. The views and sweeps to be obtained will vary depending on the structure being examined. Helpful TEE views for this evaluation are as noted below and as discussed in detail in Chapter 4, but  may include others: • For the superior vena cava: midesophageal bicaval (ME Bicaval; transducer angle ~90°–110°) and deep ­transgastric atrial septal (DTG Atr Sept; transducer angle ~80°–90°) views

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

Fig. 20.1  Imaging in the ME 4-Ch view post heart transplantation. The anastomosis of the donor left atrium (LA) to the cuff of the recipient left atrium creates an area of echogenicity (arrow) that can be mistaken for a thrombus. LV left ventricle, RA right atrium, RV right ventricle

• For the inferior vena cava: transgastric inferior vena cava/ hepatic veins (TG IVC/Hep veins; transducer angle ~80°– 100°) and DTG Atr Sept views  with adjustments in the imaging plane to ~120°–140° • For the pulmonary artery: midesophageal right ventricular inflow-outflow (ME RV In-Out; transducer angle ~50°–70°), upper esophageal pulmonary artery (UE PA; transducer angle ~0°–20°), and deep transgastric right ventricular outflow tract  (DTG RVOT; transducer angle ~50°–90°) views • For the aorta: midesophageal long-axis (ME LAX; transducer angle ~120°–140°), midesophageal ascending aorta long-axis (ME Asc Ao LAX; transducer angle ~90°–110°), midesophageal five-chamber (ME 5-Ch; transducer angle ~0°–10°), transgastric long-axis (TG LAX; transducer angle ~120°–140°), and deep transgastric five-­chamber (DTG 5-Ch; transducer angle ~0°–20°) views • For the left atrial anastomosis: ME 4-Ch and ME 5-Ch views. The pulmonary veins can be examined individually in the midesophageal right (ME Rt Pulm Veins; transducer angle of ~ 0°) and the left pulmonary veins (ME Lt Pulm Veins; transducer angle ~90°–110°) views. Further postoperative assessment should include evaluation for residual defects such as a patent foramen ovale (PFO), presence of retained intracardiac air, intracardiac thrombus, assessment of atrioventricular and semilunar valve function, and estimation of pulmonary arterial pressure [6, 11]. Pulmonary hypertension after transplantation can result in acute heart failure, which can contribute to early graft loss secondary to elevated pulmonary vascular resistance, prolonged ischemic time, or poor myocardial protection [15– 17]. Suggestive findings may include right ventricular (RV) dysfunction, low tricuspid annular plane systolic excursion (TAPSE), elevated tricuspid regurgitation velocity, and inter-

637

ventricular septal flattening during systole (visualized in TG short-axis cross sections). Immediate postoperative assessment of RV and left ventricular (LV) function typically falls under the guidance of TEE.  Serial echocardiographic assessments of graft function are vital in post-transplant care [17]. The majority of these evaluations are performed by TTE. However, TEE may need to be considered rarely, in particular when transthoracic image acquisition is suboptimal due to poor acoustic windows or an open sternum, and when there are specific clinical concerns that cannot be appropriately addressed by alternate imaging modalities. Table 20.1 outlines key points for pre- and postprocedural  imaging in patients undergoing heart transplantation as presented in the Guidelines for the Use of TEE to Assist Surgical-Decision Making in the Operating Room [1], complementing the preceeding discussion.

Lung Transplantation Lung transplantation involves the transplant of cadaveric or living donor lung tissue into a recipient with end-stage intrinsic pulmonary pathology or pulmonary vascular disease. There are several types of operative techniques for lung transplantation that include: single lung, bilateral sequential, en bloc double-lung, and heart-lung procedures. In single lung (right or left) transplantation, anastomoses are created between the donor and recipient bronchus, branch pulmonary artery, and pulmonary venous cuff [18]. En bloc double-­lung transplantation consists of two lungs, distal trachea, main pulmonary artery, and a cuff of the left atrium.

Intraoperative TEE Evaluation The use of TEE during lung transplantation is variable among institutions, although it has been strongly advocated for this application [7, 19, 20]. When used, preoperative TEE assessment allows for a comprehensive evaluation of cardiac anatomy, identification of any intracardiac pathology such as communications at the atrial level (e.g., PFO)  that may  need to be addressed concomittantly, characterization of valvar disease (when present), and assessment of biventricular function [21]. In the post-lung transplant evaluation, TEE is useful in the assessment of pulmonary arterial and pulmonary venous anastomotic connections, valve function, and myocardial contractility [22]. Pulmonary venous return should be examined in detail to exclude any stenosis or thrombosis (Fig. 20.2, Video 20.2). Given the proximity of the pulmonary veins to the TEE probe, this imaging ­modality is superior to TTE and therefore the mainstay for evaluating pulmonary venous abnormalities after lung transplant surgery[23, 24].

638

R. M. Friesen and L. T. Young

Table 20.1  Key points for imaging pre- and postprocedure in patients undergoing heart transplantation

Abbreviations: 2Ch, Two-chamber; 4Ch, four-chamber; 5Ch, five-chamber; 2D, two-dimensional; 3D, three-dimensional; CFD, color flow Doppler; EF, ejection fraction; FAC, fractional area change: IVC, inferior vena cava; IVS, inteventricular septum; LA, left atrium; LAA, left atrial appendage: LAX, long axis; MC, mitral commissural; ME, mid-esophageal; PA, pulmonary artery, RA, right atrium; RV, right ventricle; RVOT, right ventricular outflow tract; SAX, short axis; SV, stroke volume; SVC, superior vena cava: TAPSE, tricuspid annular plane systolic excursion; TG, transgastric; UE, upper esophageal. Reprinted from Nicoara el al. [1]; with permission from Elsevier 

a

b

Fig. 20.2  Midesophageal imaging of the pulmonary veins post lung transplantation. Panel a, extensive thrombus is present in the right pulmonary veins; Panel b, normal flow by color Doppler is documented in the contralateral left pulmonary veins

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

Heart and Lung Transplantation Among pediatric patients considered for heart-lung transplantation, the most common indications include CHD, idiopathic pulmonary arterial hypertension, and cystic fibrosis. The worldwide number of these procedures in children have declined progressively over time, attributed to a great extent to challenges related to organ allocation policies, to concerns regarding post-transplant outcomes, and to advances in the care of these patients, which have avoided the need for such interventions. When performed, heart-lung transplantation is considered by many a form of palliation, in contrast to transplantation of other solid organs which are associated with better median survival.

Intraoperative TEE Evaluation Given the fact that the organs are transplanted en bloc, the anastomotic connections are usually limited to the trachea, the caval veins, and the aorta. The same TEE views discussed in prior sections can be applied in the post-transplant assessment of these patients.

Liver Transplantation Pediatric liver transplantation is usually indicated in those with end-stage liver disease allowing for significantly improved clinical outcomes in this patient population. Indications range from cholestatic liver diseases (extra and intrahepatic cholestasis), metabolic disorders, and other conditions (e.g., cystic fibrosis, liver tumors). The various operative techniques include whole-liver, reduced-size liver, living-related liver, and split-liver transplantation [25]. In essence, the surgical intervention involves the creation of venous and arterial anastomoses, followed by biliary reconstruction. In children there is generally no need for veno-­ venous bypass during the procedure. The utility of TEE for perioperative monitoring during liver transplantation has been recognized [26], however, consensus is lacking, particularly regarding its use in pediatric patients. Significant hemodynamic instability is known to occur during liver transplantation, with adult studies reporting cardiac arrest occurring in up to 5% of patients [27]. Specific issues related to TEE and liver transplantation are as follows:

 afety of TEE in Liver Transplantation S The use of TEE has been well reported during liver transplantation [28–30]. While generally considered safe, patients with cirrhotic livers may also have esophageal varices, which develop to decompress the hypertensive portal vein circulation, and these can potentially increase the risk for bleeding during blind esophageal instrumentation from a TEE probe [31]. Several studies have found the risk of complications in patients with Grade 1 or 2 esophageal varices to be low [32]; however, significant caution has been suggested in the pres-

639

ence of Grade 3 varices, and it has been proposed that transgastric views should be avoided [28, 33]. The presence of esophageal varices is considered a relative contraindication to TEE imaging in various TEE guideline recommendations both in children and adults [34, 35]. However, given the low incidence of TEE-related variceal bleeding and the increasing TEE imaging experience in this patient population, this recommendation has recently been challenged [36].

 reoperative Liver Transplant Evaluation P While TTE is likely to be the more frequently used modality in the preoperative evaluation of pediatric liver transplant patients, TEE can be useful when acoustic imaging is suboptimal and important clinical questions remain. Preoperative evaluation in liver transplant recipients should include a comprehensive assessment for congenital heart defects. Children with Alagille’s syndrome (a form of cholestatic liver disease due to a paucity of bile ducts), for example, represent of a group of patients with frequently associated significant structural cardiovascular abnormalities (e.g., pulmonary artery hypoplasia or stenosis). Even the identification of a PFO can be of relevance in any child undergoing liver transplantation, as paradoxical embolization of air or thrombus represent potential complications during the reperfusion phase of the procedure. I ntraoperative Management During Liver Transplantation Patients with end-stage liver disease are typically considered to be in a high-output state with low systemic vascular resistance [31, 37]. TEE imaging can be utilized after induction of anesthesia and throughout the three phases of the surgical procedure, namely phase I (pre-anhepatic phase), phase II (anhepatic phase), and phase III (reperfusion phase) to assess intravascular volume, cardiac filling, and ventricular function [31]. While the anhepatic phase can be more hemodynamically stable as compared to other phases of the operation, hypovolemia and biventricular dysfunction can be present [38]. Graft reperfusion has been associated with hemodynamic instability [27, 31]. This phase can be characterized by significant fluid and electrolyte shifts, bradycardia, increased pulmonary arterial pressures and vascular tone, and biventricular dysfunction [39]. As the etiology of hemodynamic instability may initially be unclear, TEE monitoring can help identify potential causes such as ventricular dysfunction, diminished preload, and/ or thrombus within the IVC, heart or proximal pulmonary arteries.

Mechanical Circulatory Support in Children Extracorporeal Membrane Oxygenation General Considerations Extracorporeal life support, which is also known as extracorporeal membrane oxygenation (ECMO), is a form of mechanical assistance used for both respiratory and cardiac support that

640

can be used in all ages [40, 41]. Over time this type of support has been increasingly used worldwide. Indications for pediatric ECMO differ from those in adults and include primary respiratory failure, cardiac failure, or a combination of both [42, 43]. The primary indication for ECMO support for cardiac failure in children is CHD. Echocardiographic evaluation is important in determination of ECMO candidacy; it also plays a vital role during support, weaning, and post support surveillance. TEE in these types of settings can represent the preferred modality to assess cardiac structure and function, indications for ECMO, cannula position, and provide assistance in the evaluation of mechanical support complications [44].

Most Common Types of ECMO Veno-arterial (VA) ECMO Veno-arterial ECMO is indicated for primary cardiac failure with or without respiratory failure [44]. This type of support is comprised of two cannulas, one providing inflow from and the other providing outflow to the patient, connected to an external heart-lung bypass circuit that allows for complete cardiac and respiratory support. The specific sites of cannulation depend on patient age, size, and indication for support [45]. For peripheral cannulation, the venous cannula is inserted either in the internal jugular vein extending to the SVC (Fig. 20.3) or in the femoral vein extending into the IVC for larger patients. In the case of central/transthoracic cannulation, the right atrium serves as the typical location for the venous cannula. The venous cannula drains deoxygenated blood from the patient toward the mem-

Fig. 20.3  Chest radiograph of child supported by Veno-Arterial ECMO. Note the peripheral placement of the cannulas through the neck. The venous cannula (v) is in the superior vena cava via the internal jugular vein and the arterial cannula is positioned in the carotid artery (A)

R. M. Friesen and L. T. Young

brane oxygenator. The oxygenated and heated blood is then directed back into the arterial system of the patient via the arterial cannula. For peripheral cannulation, the arterial cannula can be inserted in the right common carotid artery extending into the innominate artery for neck cannulation or in a femoral artery in larger patients. In the setting of central cannulation, the arterial cannula is inserted directly into the ascending aorta. Veno-venous (VV) ECMO Veno-venous ECMO is indicated for primary respiratory failure without the need for cardiac support. A venous cannula drains deoxygenated blood, and after the circuit oxygenates the blood, this is infused back into the venous system. This can be achieved with two cannulas in a larger patient with one in the SVC and the other inserted via the femoral vein extending to the IVC. A more practical alternative (if feasible) is a double lumen, bicaval cannula placed in the right internal jugular vein. The double lumen cannula drains deoxygenated blood from ports in the SVC and IVC. The oxygenated blood is then returned to the patient via a separate infusion port within the right atrium directed at the tricuspid valve [40]. Veno-venous-arterial (VVA) ECMO Veno-venous-arterial ECMO can be used when there is primary respiratory failure requiring VV ECMO, but the patient develops cardiovascular compromise requiring placement of an arterial cannula for hemodynamic support, or there is insufficient unloading requiring increased venous drainage in VA ECMO. In this setting, an additional venous cannula is added and connected to the other venous drainage prior to returning to the oxygenator [46]. The additional venous cannula, for example, can be used for left atrial decompression.

TEE Evaluation While TTE often has enough spatial resolution for full evaluation of ECMO in neonates and small children, TEE can be used if TTE is inadequate. A number of echocardiographic parameters have been outlined that facilitate clinical care in patients on ECMO support as listed in Table 20.2 [44, 47]. Although the table pertains to adult patients on ECMO, the echocardiographic parameters noted, as discussed throughout this textbook, are also applicable to pediatric patients on ECMO, although the cardiac pathologies and indications for support might differ. The main focus of echocardiographic assessment consists of evaluation of cannula position, ventricular function, and surveillance of complications. The discussion that follows addresses the role of TEE in monitoring correct cannula positioning and ECMO-related complications. TEE in many cases is the preferred modality for cannula positioning during percutaneous cannula placement. Functional evaluation of both ventricles, an important component of this assessment, is not discussed in detail as it is comprehensively addressed in Chapter 5 of this textbook.

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

641

Table 20.2  Echocardiographic parameters on ECMO Monitoring on ECMO

Weaning from ECMO: measurements at baseline and with stepwise decrement on flows

Venovenous ECMO

Venoarterial ECMO

Biventricular size and function Biatrial size and volume Follow up of any pre-existing pathology Cannula position

Biventricular size and function Biatrial size and volume Follow up of any pre-existing pathology Mitral/aortic regurgitation

Pericardial effusion IVC size and collapsibility

Opening of aortic valve Intracavitary spontaneous echo contrast/intracavitary thrombus Aortic thrombus Cannula position Pericardial effusion

LVEF RV size and function (TAPSE, FAC, S at tricuspid annulus) Paradoxical septum TR and RVSP

IVC size and collapsibility LVEF LVOT VTI S wave at lateral annulus RV size and function TR and RVSP

ECMO extracorporeal membrane oxygenation, FAC fractional area change, IVC inferior vena cava, LVEF left ventricular ejection fraction, LVOT VTI left ventricular outflow tract velocity time integral, RV right ventricle, RVSP right ventricular systolic pressure, TAPSE tricuspid annular plane systolic excursion, TR tricuspid regurgitation. From Douflé G, Roscoe A, Billia F, Fan E. Echocardiography for adult patients supported with extracorporeal membrane oxygenation. Crit Care. 2015;19:326. (Open Access, available via license CC BY 4.0)

Cannula Position Veno-arterial ECMO • For the venous cannula: In both femoral and neck cannulation the venous cannula tip should be located near the right atrium, extending either from the IVC or the SVC, respectively. Venous cannula position can be evaluated by ME Bicaval view, midesophageal modified tricuspid valve view (ME Mod Bicaval TV; transducer angle ~50°– 70°), TG IVC/Hep veins, and DTG Atr Sept views (Figs. 20.4 and 20.5, Videos 20.3 and 20.4). If the cannula is inserted through a sternotomy, the ME 4-Ch view is usually suitable for this evaluation. • For the arterial cannula: In peripheral VA ECMO via the neck, the arterial cannula tip should terminate in the innominate artery at the junction to the aortic arch [48]. This is often challenging to see by TEE, however potential visualization can be achieved with the upper esophageal aortic arch longand short-axis views (UE Ao Arch LAX; transducer angle ~0°–10°; UE Ao Arch SAX: transducer angle ~70°–90°). In central cannulation, the arterial cannula can be visualized in the ascending aorta in a ME Asc Ao LAX view. A femoral arterial cannula cannot be visualized via TEE. In this case, point-of-care ultrasound may be of assistance. Veno-venous ECMO • For the venous cannula: In larger patients, two venous cannulas can be utilized, with the venous drainage cannula inserted via the femoral vein advanced into the IVC and the return cannula placed in the internal jugular vein into the mid-right atrium [44]. Alternatively, a dual-lumen bicaval cannula such as the Avalon catheter (Maquet) can

Fig. 20.4  ME Bicaval view displaying the inferior vena cava cannula (asterisk), advanced through a femoral approach into the right atrium (RA) for peripheral extracorporeal membrane oxygenation support. SVC superior vena cava

be placed by neck cannulation with two venous drainage ports located in the cavae with a return port in the mid right atrium, aimed at the tricuspid valve. Cannula position can best be visualized with the ME Bicaval view (Fig. 20.6, Video 20.5), ME Mod Bicaval TV, and DTG Atr Sept views. The TG IVC/Hep veins view is particularly helpful to ensure the cannula is within the IVC and not extending into the hepatic veins.

642

R. M. Friesen and L. T. Young

Inadequate Decompression Adequate decompression and emptying of cardiac chambers is essential while on ECMO support. Left heart dilation can potentially lead to pulmonary edema, intracardiac thrombus, and subendocardial ischemia [44]. Should the left heart have inadequate decompression, TEE can be used to evaluate the presence of an atrial level shunt, and in the case of an intact atrial septum, can guide an atrial septostomy, stenting or any other procedure aimed at atrial decompression. TEE guidance during atrial septostomy is addressed elsewhere in this textbook (Chapter 21).

Fig. 20.5  ME Bicaval 2D and color Doppler views displaying the superior vena cave (SVC) cannula (asterisk) advanced through an internal jugular vein approach into the right atrium (RA) for peripheral extracorporeal membrane oxygenation support. LA left atrium, SVC superior vena

Weaning While there are many clinical determinants that factor into weaning and decannulation from ECMO, echocardiographic evaluation of ventricular and valvular function during weaning can be a vital tool in clinical decision making. In weaning VV ECMO, assessment of right ventricular function and presence of pulmonary hypertension is essential and can be best evaluated in the ME 4-Ch, ME RV In-Out, ME Mod Bicaval TV, and TG Mid Pap SAX views. The examination may include an assessment of RV function (qualitative, quantification of TAPSE, measurement of fractional area change [FAC]) from multiple views, and estimation of RV systolic pressure using spectral Doppler evaluation of tricuspid or pulmonary regurgitant jets (refer to section on Pulmonary Hypertension).

Ventricular Assist Devices

Fig. 20.6  ME Bicaval 2D and color Doppler views  obtained during positioning of an Avalon bicaval dual-lumen catheter (asterisk) for initiation of extracorporeal membrane oxygenation support. LA left atrium, RA right atrium, SVC superior vena

Mechanical Support Complications Pericardial Effusion Systemic anticoagulation required for ECMO increases the risk of  bleeding, which could potentiate a pericardial effusion and tamponade. If transthoracic views are inadequate, TEE might be considered. The ME 4-Ch, ME RV In-Out, transgastric mid papillary short-axis (TG Mid Pap SAX; transducer angle ~0°–20°), and  DTG RVOT views can be helpful in this evaluation. Cannula Malposition/Thrombi Inadequate flow of the circuit or abnormal inlet or outlet pressures can be indicative of cannula malposition or thrombus. The TEE views described in the section above can be used to ensure optimal positioning of the cannulas and to confirm that they are not obstructed by thrombus [44, 49].

General Considerations The miniaturization and development of mechanical circulatory support devices suitable for use in infants and small children has significantly lagged behind that for adults but has expanded in recent years. The available VADs for application in the pediatric population now include a number of pulsatile and continuous-devices [50, 51]. While the specific choice of device depends on the underlying anatomy, patient age and size, at the current time almost one-third of pediatric patients undergoing heart transplantation are bridged from a VAD [52]. As their use increases and types of devices continue to diversify for infants and small children [53], accurate assessment by echocardiography becomes imperative. While TTE is the mainstay of long-term evaluation and surveillance in these patients, TEE allows for high-quality imaging immediately following device placement and provides benefits in the evaluation of potential complications which may not otherwise be adequately assessed by TTE. Types of Devices Pulsatile and Continuous-Devices Ventricular assist devices in children can be divided into pulsatile and continuous-flow devices as listed in Table 20.3. A

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

well-known pulsatile VAD in children for long-term support is that of the Berlin Heart EXCOR, a paracorporeal, durable device driven by a pneumatic external pump which provides pulsatile flow to the aorta (Fig.  20.7). A unique advantage is its variety of cannula sizes and pumps that can facilitate the appropriate selection for smaller patients, especially neonates as small as 3 kg in weight (Fig. 20.8). Additionally, the device can be upsized to accommodate growth [54]. Durable implanted continuous devices, such as the HeartMate 2/3 LVAD and HeartWare HVAD, are more common for larger-­ size patients and are run by centrifugal pumps (Fig.  20.9). These have been used in patients post interventions for CHD with heart failure as either bridge to transplant or destination therapy (Fig.  20.10). Ongoing research on investigational devices and clinical trials may allow additional devices to be incorporated into clinical practice in the near future. A promising implantable device specifically designed for small children is the Infant Jarvik VAD (Fig.  20.11) currently undergoing clinical evaluation. Another potentially useful device in small children is the MVAD pump currently under investigation (Fig.  20.12). Survival outcomes for patients

643

with continuous devices appear to be more favorable than those supported with pulsatile VADs [52]. Temporary Devices In recent years, temporary VADs have become increasingly utilized in pediatric mechanical circulatory support, providing an alternative to ECMO [50]. For smaller patients, centrifugal pumps such as the Rotaflow and PediMag, implanted by direct canalization, are available. Larger-sized patients have the option of percutaneously placed VADs. Initially, the TandemHeart was used for short-term support (Fig.  20.13) and in recent years the Impella  catheter has become the favored device (Fig. 20.14) [55–58]. Adult devices have also been modified for use in the pediatric age group [59, 60].

TEE Evaluation Although specific implantation techniques vary among devices, echocardiography plays an important role prior to, during, and after implantation. The imaging modality of choice before and after VAD placement is TTE, but TEE can be helpful if TTE imaging windows are inadequate, and is

Table 20.3  Selected ventricular assist devices in infants, children, and adolescents (currently in used or undergoing clinical trials) Device Type Intracorporeal Continuous-Flow

Device Name HeartMate 3 LVAD HeartWare HVAD HeartWare MVAD Infant Jarvik PediMag/CentriMag RotaFlow EXCOR Pediatric TandemHeart Impella

Paracorporeal Continuous-Flow Paracorporeal Pulsatile-Flow Percutaneous Continuous-Flow

a

Manufacturer Abbott Medtronic Medtronic Jarvik Heart Abbott Getinge Berlin Heart LivaNova AbioMed

b

Fig. 20.7  Images of a Berlin Heart EXCOR LVAD. Panel a, inflow cannula being implanted in the LV apex. Panel b, pediatric pump after implantation. The intake (inflow) and output (outflow) cannulas enter

the patient’s thorax, as shown. The other tube is connected to an external pneumatic driver

644

R. M. Friesen and L. T. Young

a

b

c

d

Fig. 20.8  Varieties of pumps and cannulas for the Berlin Heart EXCOR paracorporeal pump. Panel a, pump range. Panel b, atrial cannulas. Panel c, apex cannulas. Panel d, arterial cannulas. Reproduced with permission from Berlin Heart, Inc.

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

645

Fig. 20.11  Image of Infant Jarvik ventricular assist device. Reproduced with permission from Dr. Robert Jarvik, MD (Jarvik Heart, Inc.) Fig. 20.9 Image of HeartWare HVAD ventricular assist device. Reproduced with permission from Texas Children’s Hospital

Fig. 20.12  Image of HeartWare MVAD system. Reproduced with permission from Medtronic

vital at the time of implantation and of significant utility in the assessment of specific clinical questions, for example, in the exclusion of thrombus. Table 20.4 depicts the key points for the pre- and postprocedure assessment for LVAD placement as summarized in the Guidelines for the Use of TEE to Assist Surgical-Decision Making in the Operating Room [1]. Fig. 20.10  Image of HeartWare HVAD ventricular assist device as would be applied in a patient with hypoplastic left heart syndrome after Fontan palliation with end-stage heart failure. Reproduced with permission from Texas Children’s Hospital

Chamber Size and Ventricular Function Baseline anatomy, including ventricular size and function, are likely assessed by TTE or other imaging modal-

646 Fig. 20.13  Image of TandemHeart system. Reproduced with permission from Naidu SS. Novel percutaneous cardiac assist devices: the science of and indications for hemodynamic support. Circulation. 2011;123:533–43

Fig. 20.14  Image of the family of Impella circulatory support devices. Reproduced with permission from Abiomed

R. M. Friesen and L. T. Young

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

647

Table 20.4   Key points for the pre- and postprocedure assessment for intracorporeal LVAD placement

Abbreviations: AR, Aortic regurgitation; CFD, color flow Doppler; CPB, cardiopulmonary bypass; IAS, interatrial septum; IVS, interventricular septum; LVAD, left ventricular assist device; RA, right atrium; RV, right ventricle; TR, tricuspid regurgitation. Reprinted from Nicoara el al. [1]; with permission from Elsevier

windows are inadequate and can also in some cases guide changes in device settings.

Fig. 20.15  TG Mid Pap SAX view in a child undergoing preoperative TEE during LVAD implantation. The LV is severely dilated with a thinned-out wall consistent with dilated cardiomyopathy and end-stage cardiac disease

ity during patient selection for VAD placement. TEE provides confirmatory information regarding the the need for mechanical circulatory support before the procedure is undertaken (Fig. 20.15, Video 20.6). At the time of implantation, TEE can be used to evaluate LV decompression and for immediate evaluation of RV systolic function (Video 20.7) as this can acutely worsen after LVAD placement [61]. The decision to place a biventricular VAD (BiVAD) is often made in the operating room after placement of the LVAD, so real time assessment of RV function by TEE is necessary. Post implantation, chamber size and function, along with other important surveillance parameters are typically assessed by TTE, however TEE can be used when imaging

Intracardiac Structure and Valvular Function Prior to implantation, evaluation of valve structure and most importantly, competency, is important to establish a baseline as some patients may benefit from valve repair at the time of device implantation [29]. It is also of importance to evaluate all valves after device placement (Videos 20.8 and 20.9). This TEE examination should follow the format outlined in Chapters 4 and 9 for atrioventricular and semilunar valve evaluation. Worsening of tricuspid regurgitation after LVAD placement—as depicted in the ME 4-Ch, ME RV In-Out, and ME Mod Bicaval TVviews—may be another marker for RV failure, which may prompt consideration for RV mechanical support. Valve injury during implantation of durable VADs is rare, but TEE can be helpful in defining the proximity of percutaneously placed temporary VADs to valves during insertion [58, 62]. Assessment of aortic valve regurgitation after VAD placement should be performed—assisted by the ME LAX and DTG 5-Ch views—as an increase in regurgitation can increase preload on the LVAD, causing changes in VAD flows parameters [63]. An important parameter that is helpful in the adjustment of device parameters in an LVAD is the determination of aortic valve opening. This evaluation can be perfomed in the views that display the aortic valve in short or long axis (Video 20.10). The presence of intracardiac shunts, such as a PFO or a residual atrial shunt after septostomy, if previously performed for left atrial decompression in patients undergoing other forms of circulatory support, should be assessed by TEE for potential closure at the time of VAD placement.

648

R. M. Friesen and L. T. Young

Persistent intracardiac shunts after implantation can result in right-to-left shunting due to diastolic suction from the VAD leading to systemic arterial desaturation or potential paradoxical embolus [63].

wall which may cause obstruction [63, 64]. At times this is challenging to evaluate due to the artifact created by the device. Assessment of velocity across the inflow cannula may help identify obstruction. Data in pediatric devices is lacking regarding specific cutoffs for normal and abnormal inflow cannula blood flow velocities, however adult data suggest that a peak velocity > 2.3 m/sec may be indicative of obstruction [62, 63]. The outflow of an implanted long-­ term VAD such as a HeartWare HVAD pump consists of a dacron graft sewn into the ascending aorta in an end-to-side fashion. The assessment of flow from the graft as it enters the aorta is facilitated by color Doppler interrogation in a combination of views that may include the midesophageal aortic valve long-axis (ME AoV LAX, transducer angle ~120°–140°, Fig. 20.18, Video 20.13) and ME Asc Ao LAX views. Although unlikely to be the case, increased velocity at the ouflow anastomotic site into the aorta, along with clinical suspicion, may indicate obstruction at that limb. During placement of the Impella device and when potential adjustments of catheter position are required, echocardiographic guidance by TTE and/or TEE plays a critical role in order to avoid damage to the mitral valve apparatus and optimize positioning of device inlet and outflow areas (refer to case example #1) [56].

Inflow and Outflow Cannula Position The specific type of device will determine relevant information in terms of cannula position. After placement of an implanted LVAD, the inlet cannula position can be assessed by TEE in several views starting from a ME 4-Ch view (Fig. 20.16, Video 20.11), then navigating throught the ME 5-Ch, midesophageal 2-chamber (ME 2-Ch, transducer angle ~80°–100°), and ME LAX views (Fig.  20.17, Video 20.12). The inlet orifice should be free from a ventricular

Thrombi and Cardiac De-Airing The presence of intracardiac thrombi should be assessed prior to VAD implantation, as these pose a risk for embolic stroke or cannula obstruction [29]. In patients with systolic functional impairment, the evaluation for thrombi in areas of low-flow or ‘swirling’, such as the apex of the LV and left atrial appendage is particularly important. As the left atrium is usually dilated in most cases of end-stage cardiac disease, imaging of the left atrial appendage can be performed relatively easily in the midesophageal left atrial appendage view

Fig. 20.16  ME 4-Ch view post LVAD implantation  depicting the inflow cannula (arrows)  positioned within the left ventricle (LV). LA left atrium, RA right atrium, RV right ventricle

a

b

Fig. 20.17  Images post implantation of an LVAD. Panel a, modified ME LAX view (transducer angle 88°) shows inflow cannula (asterisk) well-­ positioned within the ventricle (LV). Panel b, color Doppler of the inflow cannula in the same view. AoV aortic valve

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

a

649

b

Fig. 20.18  Images post implantation of an LVAD. Panel a, ME AoV LAX view focusing on the outflow cannula (asterisk) in the ascending aorta (Ao). Panel b, color flow Doppler over the outflow cannula in the same view

and in these cases, TEE can help evaluate the effusion or the presence of chamber collapse, which could impact VAD performance.

Pulmonary Hypertension

Fig. 20.19  ME LAA 2D view displaying a dilated left atrial appendage (arrow) in the same child with dilated cardiomyopathy depicted in Fig. 20.15. LA left atrium, LAA left atrial appendage, LV left ventricle

(ME LAA; transducer angle ~90°–110°; Fig.  20.19, Video 20.14) Prior to separation from cardiopulmonary bypass during long-term VAD implantation, TEE facilates the assessment of intracardiac air. The examination should focus on views that display the LV apex (ME 4-Ch, ME 5-Ch, and ME LAX), aortic sinuses (ME LAX and ME AoV LAX), pulmonary veins (ME Rt Pulm veins and ME Lt Pulm veins), and left atrial appendage (ME LAA) [62]. Effusions Pericardial effusions and at times pleural effusions can occur after VAD placement and can usually be visualized by TTE.  Occasionally, artifact from the cannula or poor acoustic windows may preclude adequate TTE imaging,

The etiologies of pulmonary hypertension in children are primarily due to underlying CHD or idiopathic pulmonary arterial hypertension [65]. While cardiac catheterization remains the gold standard for diagnosis  of pulmonary hypertension, non-invasive evaluation by echocardiography is essential for monitoring and management of affected  children [65, 66]. The majority of echocardiographic monitoring is performed by TTE, however TEE can be utilized if acoustic windows are inadequate, for detailed anatomic assessment if questions remain, or for intraoperative monitoring during cardiac procedures and in some cases, during high-risk non cardiac surgery. TEE can also be useful during the creation of a Potts shunt or equivalent, atrial septal defect enlargement or creation and stenting (refer to case example #2), and during ventricular septal defect creation and stenting as a potential ‘pop-off’ allowing for a site of right-to-left shunting and maintenance of cardiac output.

TEE Evaluation Right Ventricular Function Right ventricular dysfunction in patients with pulmonary hypertension increases the risk for morbidity and mortality [65, 67]. Echocardiographic evaluation of RV function

650

R. M. Friesen and L. T. Young

a

b

Fig. 20.20  Fractional area change. Panel a, ME 4-Ch view tracing the right ventricular endocardial border at end-systole. Panel b, same view outlining the right ventricular endocardial border at end-diastole.

Fractional area change = (end-diastolic area – end-systolic area)/end-­ diastolic area

Fig. 20.21  Tissue Doppler myocardial performance index (MPI) of the RV. Sampling is taken from the lateral annulus of the tricuspid valve in an apical four-chamber view by TTE. This index is calculated using the formula: (b – a)/a; b = onset of isovolumic contraction time to the end of isovolumic relaxation time and a = right ventricular ejection time. An equivalent functional assessment of the RV can be performed by TEE

is challenging due to right ventricular morphology (refer to Chapter 5). Fractional area change can be used to estimate RV systolic function and is calculated from a ME 4-Ch view by measuring RV area at end-diastole and end-systole (Fig. 20.20). FAC is calculated as [68]:

 end-diastolic area – end-systolicarea 

end-diastolic area

100



Adult data suggests that RV FAC >32% is reflective of normal RV function. [66] Myocardial performance index (MPI) of the RV can estimate global RV function incorporating systolic and diastolic function. MPI is calculated as [68]:

 isovolumic contraction time  isovolumic relaxation time  ejection time



This measure can be calculated by spectral Doppler evaluation of the tricuspid valve inflow and the pulmonary outflow. The tricuspid valve inflow Doppler can be obtained using the ME 4-Ch, ME Mod Bicaval TV, or the ME RV In-Out views. The pulmonary outflow signal can be measured using the ME RV In-Out, UE PA, UE Ao Arch SAX, or DTG RVOT views. Obtaining an MPI by spectral Doppler is potentially confounded by heart rate variability between acquisitions of the tricuspid valve inflow and pulmonary outflow. MPI can also be calculated by tissue Doppler, which is acquired in a single heart beat (Fig. 20.21) [68].

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

651

An important aspect of ventricular functional assessment is that of ventricular interdependence—also referred to as ventricular coupling—where dysfunction of one ventricle may impact the function of the other ventricle due to the fact that they are enclosed within the pericardial space. In the case of RV dysfunction it is imperative to also evaluate LV function.

Estimation of Hemodynamics Spectral Doppler imaging of tricuspid and pulmonary valve regurgitant jets can provide non-invasive estimations of pulmonary arterial pressure. Systolic pulmonary arterial pressure (sPAP) can be derived by applying the simplified Bernoulli equation to the peak tricuspid regurgitant velocity (refer to Chapter 1) [69, 70]. Mean and diastolic pulmonary artery pressures can be estimated by a similar method using the pulmonary valve regurgitation jet, with mean pulmonary artery pressure estimated by the peak pulmonary valve regurgitant velocity and diastolic pulmonary artery pressure by the end diastolic regurgitant velocity [68].

Fig. 20.22  Right atrial thrombus. ME Bicaval view in a patient with a pulmonary embolism undergoing TEE imaging demonstrating an associated right atrial thrombus (arrows) attached to the atrial septum. IVC inferior vena cava, LA left atrium, RA right atrium, SVC superior vena cava

Pulmonary Embolism

TEE Evaluation

Pulmonary embolism occurs rarely in the pediatric population and in contrast to the adult patient, the majority of children with pulmonary embolism have an identifiable cause. Etiologies include the presence of indwelling catheters [71], inherited disorders of coagulation [71], long-term total parenteral nutrition [72], and dehydration.

Evaluation of the RV can best be achieved in the ME 4-Ch, ME Mod Bicaval TV, ME RV In-Out, and DTG RVOT views with both subjective evaluation and quantitative assessment of FAC and TAPSE, as discussed previously for other conditions that can affect the RV.  Ventricular septal flattening, indicative of elevated right ventricular pressures, can be assessed by TEE in a TG Mid Pap SAX view. As in the case of pulmonary hypertension of any etiology as previously noted, estimation of RV systolic pressures can be achieved by spectral Doppler evaluation of the tricuspid regurgitation jet from a ME 4-Ch, ME Mod Bicaval TV, or ME RV In-Out views. Atrial septal bowing can be visualized from the ME 4-Ch, ME Bicaval, and DTG Atr Sept views. While the ability to image the distal pulmonary vascular bed is not feasible by TEE, more proximal thrombi, particularly if large and affecting the main or proximal branch pulmonary arteries can be seen. TEE evaluation of the main pulmonary artery, bifurcation, and proximal branch pulmonary arteries can best be seen starting with a midesophageal ascending aorta short-axis view (ME Asc Ao SAX; transducer angle ~0°–30°) with manipulation of the probe cranially into a UE PA view. Direct imaging of the left pulmonary artery can be limited by its proximity to the left main bronchus, however leftward rotation and slight cranial withdrawal of the probe in a ME Asc Ao SAX view can improve visualization of the distal LPA [76, 77]. The UE Ao Arch SAX view is also helpful visualizing the main and branch pulmonary arteries.

Role of Echocardiography While computed tomography (CT) is an essential diagnostic tool in pulmonary embolism, echocardiography is useful in evaluating the effects of the disease severity, RV function, and response to treatment [73]. Impaired RV function is an important component of risk stratification for individuals with a pulmonary embolism. The primary utility of echocardiography in this case is to evaluate for RV dysfunction [73]. Echocardiography can also be used to visualize intracardiac thrombi or thrombi in the main or proximal branch pulmonary arteries (Fig. 20.22, Video 20.15) [74]. Direct visualization of pulmonary emboli by echocardiography can be challenging, if not impossible  in most cases, however,  assessment of secondary signs can aid in clinical decision making. These echocardiographic secondary signs of a pulmonary embolism include RV dysfunction, tricuspid regurgitation, and interatrial septal bowing towards the left atrium consistent with elevated right atrial pressure [75].

652

Pericardial Diseases General Considerations Diseases of the pericardium can be found in a multitude of clinical scenarios, including infectious, rheumatologic, oncologic, and post-surgical processes [78]. These include pericardial effusion and tamponade, acute, recurrent and constrictive pericarditis, pericardial masses and congenital anomalies of the pericardium. While diagnosis of pericardial diseases often requires clinical suspicion and multimodality imaging such as cardiac magnetic resonance imaging (CMR)  or CT, echocardiography is a vital component of diagnosis, monitoring and management of pericardial diseases and usually one of the first imaging modalities applied.

Specific Conditions Acute Pericarditis Acute pericarditis commonly presents with a constellation of symptoms consisting of chest pain, pericardial rub, diffuse ST elevation on ECG, often with laboratory markers of inflammation [79]. Echocardiographic evaluation can be helpful to evaluate the presence of a pericardial effusion in acute pericarditis. Pericardial Effusion Pericardial effusions can be transudative, exudative, bloody (hemopericardium), or purulent (pyopericardium) [80]. Tamponade physiology remains primarily a clinical diagnosis, but echocardiographic evaluation is vital for evaluation of the size and location of an effusion as well as assessment for evidence of tamponade physiology. Due to increased central venous pressure, the IVC and hepatic veins are often dilated with minimal inspiratory collapse of the IVC. Right heart chamber collapse occurs when pericardial pressure exceeds RV pressure. Increased duration of right heart collapse corresponds with worsening tamponade and right atrial collapse greater than one third of the cardiac cycle is highly sensitive for clinical tamponade [78]. M-mode imaging of the affected wall provides improved temporal resolution to evaluate duration of chamber collapse. Tricuspid and mitral valve inflow variation is best evaluated with spectral Doppler interrogotation over a respiratory cycle. At baseline there is typically less than 5% inflow variation of the mitral valve with inspiration, yet inflow variation greater than 30% is generally considered consistent with tamponade physiology, as is >50% variation in the tricuspid valve [78]. Constrictive Pericarditis Constrictive pericarditis is an rare condition in the pediatric population but an important pathology of the pericardium as the condition can lead to impaired ventricular filling and dia-

R. M. Friesen and L. T. Young

stolic impairment. Etiologies include infectious, idiopathic, post-surgical, and commonly post-radiation [81]. The pericardium may be thickened, scarred or calcified leading to decreased compliance for ventricular filling with the majority of filling occurring in early diastole with minimal filling from mid to end diastole, which diminishes overall cardiac output. By echocardiography this diagnosis is suggested by a thickened pericardium, respiratory variation in ventricular filling characterized by ventricular interdependence with an inspiratory shift of the interventricular septum to the left due to equalization of RV and LV diastolic pressures, dilated IVC/ hepatic veins, and a restrictive filling pattern of the RV and LV [78]. This pattern shows a greater than 25% decrease in mitral valve inflow velocity during inspiration and a greater than 40% increase in tricuspid valve inflow velocity [78]. Augmented longitudinal motion of the heart has also been described [82]. The distinction between constrictive pericarditis and restrictive cardiomyopathy is an important one, which benefits not only with the use of e­ chocardiography [83] but other use of diagnostic imaging modalities such as CMR, CT, and in some cases invasive hemodynamic assessment [84–86].

Pericardial Tumors Pericardial tumors can be both primary or metastatic. Benign tumors include teratomas, lipomas, fibromas and hemangiomas, with malignant tumors including mesothelium and angiosarcoma [78]. Some of these tumor types are discussed subsequently in this chapter. Echocardiographic evaluation of these masses should focus on location of the tumor as well as a thorough assessment of the physiologic effects of the mass, which can include pericardial effusion with tamponade or constrictive pericarditis.

TEE Evaluation  ericardial Effusion and Tamponade Physiology P Typical features of tamponade physiology and TEE views that are most helpful in their respective evaluation are as follows [87]: • Presence of pericardial effusion –– TEE views: ME-4Ch (Fig.  20.23, Video 20.16), ME 5-Ch, TG Basal SAX, TG Mid Pap SAX (Fig. 20.24, Video 20.17), TG Apical SAX, DTG 5-Ch, and DTG RVOT. It is important to perform sweeps across multiple cross sections (Videos 20.18 and 20.19) as in some cases the fluid can be seen best in a particular plane or the fluid may be loculated. • Dilated IVC and hepatic veins consistent with elevated central venous pressure –– TEE views: ME Bicaval, TG IVC/Hep veins, DTG Atr Sept

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

653

Evaluation of Constrictive Pericarditis Physiology typical of constrictive pericarditis and TEE views that are most helpful in the respective evaluation are as follows:

Fig. 20.23  ME4-Ch view displaying a small pericardial effusion at the cardiac apex (arrows). LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

• Thickened pericardium –– TEE views: ME-4Ch, ME RV In-Out, TG Basal SAX, TG Mid Pap SAX, TG Apical SAX, DTG 5-Ch, and DTG RVOT • Abnormal ventricular septal motion –– TEE views: ME 4-Ch, TG Mid Pap SAX • Dilated IVC and hepatic veins suggesting elevated central venous pressure (may also be seen in restrictive cardiomyopathy) –– TEE views: ME Bicaval and TG IVC/Hep veins. • Respiratory variation of inflow velocity –– TEE views: As for pericardial effusion and tamponade physiology When intraoperative TEE is used in constrictive pericarditis, the indication is related to planned pericardial stripping. The physiology can change significantly as the constriction related to the pericardium is relieved. An important aspect of the evaluation therefore is to document improvement in the physiology with enhanced ventricular filling. Table 20.5 depicts the key points for intraoperative imaging in patients with pericardial diseases as summarized in the Guidelines for the Use of TEE to Assist Surgical-Decision Making in the Operating Room [1].

Fig. 20.24  TG Mid Pap SAX view in the same patient depicted in Fig. 20.23 displaying the pericardial effusion towards the LV anterior wall in this cross section (arrows). LV left ventricle, RV right ventricle

• Right heart diastolic chamber collapse –– TEE views: ME 4-Ch, ME Bicaval and ME RV In-Out for delineation of right atrial and RV collapse • Respiratory variation of tricuspid valve and mitral valve inflow velocities –– TEE views:  ME 4-Ch (Fig.  20.25) and ME Mod Bicaval TV for spectral Doppler evaluation When intraoperative TEE is used in most cases of pericardial effusion with or without tamponade physiology, the indication is related to an intervention for drainage. An important aspect of the evaluation therefore is to ensure the procedure has been adequate to remove the pericardial fluid (Video 20.20).

Aortic Dissection General Considerations Aortic dissection represents the most common form of the acute aortic syndromes. It is characterized by a separation in the aortic wall between intimal and medial layers, resulting in a large intimal flap that creates a second blood-filled channel, namely, a false and a true lumen in the ascending or descending aorta (or both). The etiology of aortic dissection is thought to be due to rupture of vasa vasorum but increased shear forces, and abnormalities of aortic media, can also result in intimal tears that ultimately lead to dissection. Left unrecognized, aortic dissection can be a dangerous and potentially a catastrophic condition, with complications that can include wall rupture, pericardial tamponade, aortic regurgitation, coronary artery ischemia, and even result in death [88, 89]. The pathology is seen much more commonly in the adult age group (higher incidence of males than females, with a

654 Fig. 20.25  ME view displaying Doppler interrogation across the tricuspid (panel a) and mitral valves (panel b) to determine changes in respiratory variation that may suggest tamponade physiology

R. M. Friesen and L. T. Young

a

b

ratio between 2:1 to 5:1), with the most frequently associated condition being hypertension in approximately 80–90% of patients [89, 90]. However, congenital abnormalities of the aortic wall—notably Marfan syndrome, Loeys-Dietz syndrome, vascular Ehlers-Danlos, and other connective tissue disorders—are also associated with aortic dissection [91]. Patients with Turner syndrome have also been reported to have an increased risk of aortic dilatation and aortic dissection [92]. Other congenital abnormalities that might pre-

dispose to an “aortopathy” and aortic dissection include a bicuspid aortic valve and aortic coarctation. Iatrogenic causes that may result in aortic dissection include aortic cannula insertion for cardiopulmonary bypass and balloon dilation of aortic coarctation [93]. It should also be noted that trauma, such as deceleration injuries resulting from motor vehicle accidents, can lead to aortic pathologic conditions that range from intimal disruption to transection (rupture). These are quite rare and will not be addressed further.

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

655

Table 20.5   Key points for intraoperative imaging in patients with pericardial diseases

Abbreviations: 2Ch, Two-chamber; 4Ch, four-chamber; 5Ch, five-­chamber; 2D, two-dimensional; 3D, three-dimensional; AV, aortic valve; CFD, color flow Doppler; e’ early diatolic mitral annular velocity; IVS, interventricular septum; LA, left atrium; LAA, left atrial appendage; LAX, long axis; LV, left ventricle; MC, mitral commissural; ME, mid-esophageal; MV, mitral valve; PV, pulmonic valve; PW, pulsed-wave; RV, right ventricle; SAX, short axis; TG, transgastric; TV, tricuspid valve. Reprinted from Nicoara el al. [1]; with permission from Elsevier

Classification of Aortic Dissection

TEE Imaging of Thoracic Aorta

The Stanford or DeBakey classifications are the two commonly used for aortic dissection. These are based upon the location of the dissection. In the Stanford classification of aortic dissection, type A affects the ascending aorta and arch and type B the descending aorta, beginning beyond the brachiocephalic vessels [94]. In the the DeBakey classification type I involves the ascending and descending aorta, as well as the aortic arch; DeBakey type II involves only the ascending aorta; DeBakey type III involves only the descending aorta [95]. Typically, ascending aortic dissections (Stanford A, DeBakey II) carry much higher risk for complications compared to descending aortic dissections [89].

Standard Views Imaging modalities such as CT and CMR have assumed a primary role in the diagnosis of aortic dissection; however, TEE provides an excellent imaging alternative, offering great sensitivity and specificity because of its superior spatial and temporal resolution [91, 96, 97]. Moreover, because of its portability and availability, TEE (when performed jointly with TTE imaging) is expeditious and can serve as a rapid means to secure a diagnosis, particularly in the unstable patient. In addition to the evaluation of aortic dissection, TEE imaging of the thoracic aorta is ­useful for determining the presence of other wall abnormalities, such as hematoma,

656

or obstruction. The versatility, reliability and safety of this technique make it the preferred imaging modality in the perioperative setting [98]. Furthermore, in the intraoperative setting, TEE and/or epiaortic echocardiography are the only two modalities available to detect an iatrogenic aortic dissection related to cannulation [99]. An additional benefit of TEE in the evaluation of aortic dissection is that it readily detects and evaluates aortic regurgitation and pericardial effusion, and also assists in intraoperative assessment, although it cannot interrogate the abdominal aorta [100]. The aortic arch to some extent can be evaluated by TEE, but the position of the esophagus in relation to the aortic arch presents some challenges. Unlike TTE, the entire aortic arch and descending aorta cannot be visualized in one plane, and instead must be evaluated in sections with a combination of multiplane transducer angles and rotation of the TEE probe shaft. At the same time, the probe must be alternately advanced and withdrawn to visualize the more superior and inferior portions of the entire aorta. Because of the possibility of artifacts mimicking an aortic dissection, an important practice in 2D echocardiography is to visualize the abnormality in more than one plane. Therefore, several transducer angles (preferably orthogonal ones) should be utilized to confirm the intraluminal presence of the flap, and color-­ flow Doppler can be applied to characterize the flow patterns in and out of the false lumen. For evaluation of the ascending aorta and arch, the most relevant views are the mid to upper esophageal cross-­ sections—ME Asc Ao SAX and ME Asc Ao LAX, as well as the UE Ao Arch LAX and UE Ao Arch SAX views. A short-axis image of the proximal and mid-ascending aorta (ME Asc Ao SAX view) can be obtained in the midesophageal window at the level of the right pulmonary artery with the transducer angle between 0o and 30o. The right pulmonary artery lies posterior to the ascending aorta in this view. Continued rotation of the transducer angle to approximately 90°–110o will bring the ME Asc Ao LAX into view. Imaging along this sagittal plane and the addition of color Doppler are useful in assessing for dissection [34, 35, 101, 102]. Careful withdrawal of the probe from the mid to the upper esophagus allow for the upper esophageal views. Slow probe rotation from right to left will display the ascending aorta, then aortic arch, and finally descending aorta. The probe can be alternately advanced and withdrawn to visualize various portions of these structures. While keeping the descending thoracic aorta in view in its short axis at a transducer angle of ~0°–10o, rightward probe shaft rotation will demonstrate the upper portion of the aortic arch in a long-axis view (UE Ao Arch LAX). Additional withdrawal of the transducer cephalad can occasionally demonstrate the left subclavian artery. Turning the probe rightward will bring the mid portion of the arch into view. Forward rotation of the transducer angle to

R. M. Friesen and L. T. Young

90o will display a short-axis view of the aortic arch with the pulmonary artery in its long axis. Rotation of the probe rightward in this plane will bring the proximal arch into view, while rotation leftward will bring the distal arch into view (assumes a left aortic arch) [34, 101, 102]. The descending aorta is best visualized by rotation of the probe so that it faces posteriorly and away from the heart, using the descending aorta short- (Desc Ao SAX) and long-axis views (Desc Ao LAX) to achieve orthogonal tomographic images [34, 35]. The suggested approach is as follows: with the transducer angle at 0°–10o, the probe is rotated to the left from the ME 4-Ch to bring the descending aorta into view as a circular, short-axis image near the center of the field. Aortic imaging can be optimized by decreasing depth, reducing gain and placing the focus in the appropriate near field location. From here, the transducer angle is rotated to 90°–100o to demonstrate the descending aorta in long axis. By careful advancement and withdrawal of the probe, the entire descending thoracic and upper abdominal aorta can be visualized. Doppler interrogation of flow in the descending aorta can  assist in the assessment of proximal arch obstruction—although spectral Doppler is frequently challenged by a suboptimal angle of interrogation in this view—and may provide insight into the severity of aortic regurgitation when other views are limited [34, 35, 101, 102]. Imaging of Aortic Dissection Transesophageal imaging is often the first step for identifying and confirming the presence of an aortic dissection, and has been shown to be equally reliable for confirming or excluding dissection as helical CT or CMR [103]. Ascending aortic dissections typically occur just above the sinotubular junction on the greater curve of the aorta and just distal to the left subclavian artery [104]. An intimal tear is characterized as an undulating linear echodensity or flap within the aortic lumen separating a true from false lumen. In many instances, the false lumen is larger than the true lumen. There can be one or more re-entry sites between true and false lumens. Color-flow Doppler often demonstrates a difference in flow patterns between the true and false lumens; there can be a much lower Doppler flow velocity in the false lumen, and spontaneous echo contrast or thrombus formation will sometimes be present [89]. In some cases, flow in the two lumens occurs in opposite directions, such as when aortic regurgitation is present (Fig. 20.26, Video 20.21). In order to differentiate aortic wall disruption from artifact as previously noted, the abnormalities must be shown in several views. The false lumen is usually larger, but due to variations in the size of the communication and flow characteristics, it may be difficult to differentiate from the true lumen. The true lumen typically expands during systole with

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

657

a

b

c

d

Fig. 20.26  Dissection of the ascending and descending aorta (DeBakey Type I) in a patient with Marfan syndrome, a dilated aortic root, and significant aortic valve regurgitation. Panel a, UE AoArch LAX view, transducer angle of 0°, shows true and false lumens of the aorta. The false lumen is much larger than the true lumen in the ascending aorta and aortic arch. Panel b, retrograde diastolic flow reversal is seen only

in the true lumen by color-flow mapping. Panel c, ME AoV LAX view, transducer angle of 120°, shows the intimal flap (arrow) and true and false aortic lumens. Panel d, Desc Ao LAX view at the level of the mid esophagus, with a transducer angle of  90° (probe rotated leftward), shows the dissection extending into the  descending thoracic aorta (AoDT)

systolic movement of the intimal flap toward the false lumen. Timing of this movement can be determined by correlation with a simultaneous electrocardiocardiographic tracing. The proximal extension of the flap is important for decision-­ making regarding aortic reconstruction [102]. Linear artifacts in the ascending aorta are frequently encountered and need to be distinguished from dissection. Common artifacts include reverberations from the anterior wall of the left atrium and right pulmonary artery. Typically, linear artifacts move parallel to the aortic wall, have similar blood flow velocities on either side and extend past normal anatomic boundaries. Artifacts are also not reproducible in multiple planes [105]. Acute aortic regurgitation is often seen in association with aortic dissection, and may occur due to several mechanisms. A central jet of regurgitation may result from dilation of the sinotubular junction causing distortion of the aortic valve leaflets and poor coaptation.The dissection flap may extend into the root disrupting the leaflets and causing an

eccentric jet of regurgitation. An additional cause of regurgitation may be the concomitant presence of a bicuspid aortic valve [106, 107]. Transesophageal imaging is important for identifying additional complications seen with aortic dissection. For example, absence of coronary flow or the presence of new regional wall motion abnormalities may signal extension of the dissection to involve the coronary arteries. Rupture of a dissection into the pericardial space can result in a pericardial effusion, in which case echocardiographic signs of tamponade need to be assessed and emergent action taken to  relieve tamponade and repair the dissection. It is also critical to determine whether the dissection extends into the major arterial branches [102]. Although the preceeding discussion focuses on aortic dissection and the role of TEE in this setting, it should be recognized that patients with aortic pathologies such as aneuryms, pseudoaneurysms, and others, can also benefit from this imaging modality as discussed in case example #5.

658

R. M. Friesen and L. T. Young

Cardiac Tumors

imaging modality for their evaluation and follow-up surveillance. Cardiac magnetic resonance imaging has become There are two main categories of cardiac tumors, primary increasingly utilized for the diagnostic workup and follow and secondary/metastatic. The majority of primary cardiac up of cardiac tumors [113–116]. The role of TEE is primartumors, which originate in the heart, are benign [108–112]. ily in two settings: (a) for those patients in whom TTE is While histopathologically they may be benign, primary poor or incomplete and (b) for intraoperative assessment. cardiac tumors can cause significant morbidity due to Specifics of optimal TEE probe location and transducer arrhythmias, mass effect or embolization. The rare malig- angles, along with methods of evaluation, will depend upon nant primary cardiac tumors are typically sarcomas, which the type and location of the tumor as will be outlined in the portend a poor outcome [110]. Secondary cardiac tumors following sections. In adults, TEE has been reported to proare metastatic and malignant. They are comprised of both vide more precise depiction of tumor attachments sites and distant metastases and direct invasion [108]. Secondary extent of myocardial/pericardial involvement [117, 118]. cardiac tumors are three to four times as common in pedi- Intraoperative assessment by TEE is used to confirm locaatric patients as compared to primary tumors [109, 110]. tion and extent of tumor involvement preoperatively, as well Metastases to the heart in adults are most commonly to the as to document the adequacy of surgical resection, assess for pericardium and originate from malignancies affecting lung, residual obstruction, determine if native cardiac structures breast, esophagus, and uterus as well as other malignancies are affected, and evaluate the ventricular function in the postsuch as lymphoma/leukemia, and melanoma [111]. Non-­ operative period [119–122]. The following sections highlight Hodgkin’s lymphoma, neuroblastoma, Wilms tumor and soft relevant aspects of primary cardiac tumors and important tissue/bone sarcomas are the most common malignancies to aspects of their TEE evaluation. metastasize to the heart in chidren [109]. Direct extension to the heart can occur via the inferior vena cava in Wilms tumor (Fig. 20.27, Video 20.22), renal myosarcoma or adrenal and Rhabdomyoma hepatocellular carcinoma [108, 110]. The presentation of cardiac tumors is highly variable Rhabdomyomas are the most commonly encountered primary depending on the type of tumor and extent of involvement, cardiac tumors in the pediatric age group, comprising nearly which can include endocardium, myocardium, pericardium 60–80% of all cases [123, 124]. These are typically multiple in or a combination of these [50]. A full discussion of the clini- nature, and present along the free wall of the RV and LV, as cal presentation is beyond the scope of this chapter and the well as the ventricular septum. They can also be found within reader is refered to several resources available on the subject the atrium. There is a strong association with tuberous sclerosis; [108, 110, 111]. with estimates of 40–60% of individuals with tuberous sclerosis also having cardiac rhabdomyomas [125]. Rhabdomyomas are histopathologically benign, however clinical symptoms can be General Aspects of the TEE Evaluation present. Rhabdomyomas can lead to atrial or ventricular arrhythmias, and can also result in obstruction of blood flow if located Most cardiac tumors are well seen by TTE, particularly in near an area of inflow or outflow. Spontaneous regression over younger patients, and therefore this represents the main time is the typical natural history of these tumors, therefore surgical intervention is rarely the case and only necessary to relieve hemodynamic obstruction, or rarely if there are intractable and malignant arrhythmias caused by the tumor [125].

Fig. 20.27  Wilms tumor (arrow) invading the right atrium (RA) by direct extension from the inferior vena cava, as seen from the ME Bicaval view. LA left atrium, SVC superior vena cava

TEE Evaluation The ability to identify rhabdomyomas often begins during fetal life, as they can usually be visualized by fetal echocardiography as well as postnatally via TTE. TEE is usually unnecessary for their evaluation. However, TEE does play a significant role in the pre and postoperative assessment for patients who require surgical relief of obstruction. Rhabdomyomas are characteristically homogenous, echogenic and well circumscribed, making them easily distinguishable from the surrounding myocardium. The ME 4-Ch view serves to begin evaluation of the tumors, both ventricular and (if present) atrial (Fig. 20.28, Video 20.23). Once identified, they can be visualized in further detail with variations in transducer angle, along with anteflexion and ret-

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

a

659

b

Fig. 20.28  Large right atrial rhabdomyoma (asterisk) as depicted in a in ME Bicaval (panel a) and ME 4-Ch (panel b) views. Note the tumor location at the junction of the superior vena cava (SVC) and right atrium (RA). RV right ventricle

roflexion. Obstruction to ventricular inflow, if present, should be examined by color flow and spectral Doppler to assess for disturbed flow patterns around the tumor, and to determine a mean gradient across the area. If outflow tract obstruction is a concern, the midesophageal views such as the ME 5-Ch, ME LAX, and ME RV In-Out are well-suited to evaluate the anatomic extent of the tumor(s) and any turbulence as seen by color flow Doppler. The deep transgastric views (DTG RVOT and DTG 5-Ch) allow for optimal spectral Doppler interrogation of the ventricular outflow tracts. The transgastric views also provide other perspectives from which to visualize both right and left sided tumors. These views include the TG Basal SAX, TG Mid Pap SAX, TG Apical SAX, TG LAX, and other non-standard views of the RV.

Fibroma Fibromas are the second most common cardiac tumor encountered in the pediatric age group (10–30%) [126]. They are generally solitary and intramural, located within the ventricular septum or LV free wall [110]. When large, they can impinge significantly upon the adjacent cardiac chamber, typically the LV, causing symptoms such as congestive heart failure and cyanosis. They are usually single tumors. While uncommon, they can also involve the conduction system as well as the RV. Fibromas are known to frequently cause ventricular arrhythmias [127, 128]. As fibromas typically do not regress spontaneously, surgical resection is usually recommended.

TEE Evaluation The TEE evaluation of a fibroma generally occurs in the intraoperative setting, and is similar to that involved with the evaluation of other cardiac tumors. The tumor is best seen from the midesophageal views utilizing various planes of  interrogation. Color imaging  and spectral Doppler can

Fig. 20.29  Fibroma attached to the left ventricular (LV)  free wall, visualized from a modified ME LAX view. The fibroma (arrow) is very large, circumscribed, and has a heterogeneous appearance, studded with echolucent areas most likely representing cystic degeneration or necrosis. LA left atrium

better characterize inflow or outflow obstruction around the tumor. The echocardiographic appearance of a fibroma is typically a single, bright echo dense intramural mass with calcifications and cystic areas within the tumor (Fig. 20.29, Video 20.24).

Myxoma Myxomas are the most common primary cardiac tumors in adults, but are less likely to be seen in children [110, 129]. The typical location is that of the left atrial cavity (75–90%), but they can also be found in the right atrium or involve the ventricles [129, 130]. The clinical manifestations are variable, but include embolic phenomena and/or obstruction to blood flow, leading to syncope or congestive heart failure. Constitutional symptoms such as fever, malaise, weight loss or myalgias/arthralgias can also be present. Familial occur-

R. M. Friesen and L. T. Young

660

dilection for the right atrium and ventricular septum [132]. Teratomas are usually detected by fetal echocardiography or during the neonatal period. They most commonly are seen in the pericardial space, but can also invade the atrial or ventricular walls. Teratomas can often attach to the aortic root or pulmonary trunk they can cause pericardial effusions and become quite large. The size of the tumor and/or pericardial effusion can lead to tamponade physiology, requiring intervention.

Fig. 20.30  A moderate size lobulated left atrial myxoma is displayed from a ME 4-Ch view. The tumor is attached to the left atrial aspect of the interatrial septum, just posterior to the aortic root. LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

rence is reported in approximately 7–10% of all myxomas, generally in younger patients. These familial occurrences are associated with multiple endocrine syndromes including LAMB (lentigines, atrial myxoma, mucocutaneous myxoma, and blue nevi) and NAME (nevi, atrial myxoma, neurofibromata, and ephelides).

TEE Evaluation Myxomas are gelatinous in consistency and can be pedunculated. By echocardiography they have a globular, lobulated or fimbriated appearance, often with a pedicle. There can be small lucencies and calcifications within the tumor, which leads to a heterogeneous appearance. Left atrial myxomas characteristically have attachments to the atrial septum, but can also form attachments to other parts of the left atrium or mitral valve (Fig. 20.30, Video 20.25). Depending on the size, a myxoma can lead to  mitral inflow obstruction. Surgical resection is the treatment of choice given potential complications, thus, TEE is crucial in the pre and postoperative evaluation [131]. Adequate assessment of all attachments of the myxoma will help in presurgical planning. Postoperative assessment focuses on completeness of the resection and should include evaluation of the mitral valve, left atrium, atrial septum, and ventricular function. Myxomas are best characterized in the midesophageal views with variable probe transducer angles. Color and spectral Doppler allow for assessment of the atrial septum and the mitral valve, and are particularly helpful for evaluation of the degree of involvement,obstruction and integrity of the mitral valve during the intervention.

Other Cardiac Tumors Hemangiomas and teratomas are two other primary cardiac tumors that can be encountered in children. Hemangiomas can be located anywhere within the heart, but have a pre-

TEE Evaluation The characteristic echocardiographic feature of a hemangioma is that of a tumor with multiple echolucent spaces and color Doppler demonstration of vascularity within the mass (Fig.  20.31, Video 20.26). Teratomas appear encapsulated and heterogeneous by echocardiography [123].

Summary This chapter describes various settings, other than CHD, where TEE can provide valuable adjunctive imaging, including organ transplantation, mechanical circulatory support, pulmonary embolism, pulmonary hypertension, pericardial disease, aortic dissection, and cardiac tumors. Specific imaging approaches for optimization of the TEE information obtained in each setting are provided. An in-depth understanding of non-congenital TEE applications is essential in the comprehensive echocardiographic evaluation of pediatric cardiovascular disease. This knowledge base is also fundamental in the long-term surveillance of both children and adults who may develop other clinical problems related or unrelated to their primary congenital pathology.

Case-Based Examples Case #1 Subject:  Impella ventricular assist device Clinical History:  12-year-old female who presented with several week history of cough, congestion, dyspnea, and weight loss and was found to have dilated cardiomyopathy. While undergoing evaluation for VAD implantation as a bridge to cardiac transplantation she  developed frequent runs of ventricular tachycardia, requiring more urgent intervention for stabilization. She was taken to the cardiac catheterization laboratory for transcatheter placement of an  Impella temporary VAD.  Under TEE guidance, the position of the Impella catheter was optimized. The patient’s hemodynamic status stabilized on full hemodynamic  support. She was referred for a durable VAD four

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

a

661

b

c

Fig. 20.31  Right atrial hemangioma as seen from a modified ME RV In-Out view. Panel a, note the markedly heterogenous nature of the large mass (arrow) in the right atrium (RA). The neonate underwent

surgery and the tumor was removed (panels b and c). Ao ascending aorta, MPA main pulmonary artery

days later and ultimately received an orthotopic heart transplant.

• Additional imaging (not shown) demonstrated the tip of the catheter to be free within the LV cavity, away from the mitral valve.

TEE Findings: • ME LAX 2D and color Doppler images  (Fig. 20.32, Video 20.27) show the Impella device across the LV outflow tract with its “bend” at the level of the aortic valve/annulus. This places the device at optimal position within the LV cavity. Mild aortic valve regurgitation is present due to the Impella catheter crossing in retrograde fashion through the aortic valve (Video 20.27). • ME AoV LAX 2D and color Doppler targeting the ascending aorta (Fig. 20.33, Video 20.28) demonstrate appropriate positioning of the Impella device outflow in the ascending aorta above the level of the aortic valve. There is flow aliasing at the outlet which is completely within the ascending aorta.

Discussion:  The Impella device provides temporary support to the LV to decrease myocardial oxygen demand and augment cardiac output. Several of these pumps  are available  including one designed for right heart support. The Impella 2.5 and CP heart pumps are positioned with the inlet ~3.5 cm below the level of the aortic annulus and the outlet within the ascending aorta. Positioning of the device is assisted by TEE and also by following the waveforms displayed on a monitor placement signal and motor current.

Suggested Reading/References 1. Bradley B.  Anderson, Charles D.  Collard; Images in Anesthesiology: Proper Positioning of an Impella 2.5 and CP Heart Pump. Anesthesiology 2017;127(6):1014

662

R. M. Friesen and L. T. Young

Fig. 20.32  Case #1. ME LAX 2D and color Doppler imaging shows an Impella device across the LV outflow tract with its “bend” at the level of the aortic valve/annulus. This places the device at optimal posi-

tion within the left ventricular cavity. Mild aortic valve regurgitation is present due to the Impella catheter crossing in retrograde fashion through the aortic valve (AoV)

Fig. 20.33  Case #1. ME AoV LAX 2D and color Doppler imaging targeted in the ascending aorta demonstrates appropriate positioning of the Impella device outlet opening in the ascending aorta (asterisk)

above the level of the aortic valve (AoV). There is flow aliasing at the outlet which is completely within the ascending aorta

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

a

663

b

Fig. 20.34  Case #2. Potts shunt. Panel a,  Desc Ao LAX view shows a Potts shunt (asterisk) placed between the left pulmonary artery and descending aorta (DAo). Panel b, color flow Doppler demonstrates right-to-left shunting across the aortopulmonary communication

Case #2 Subject:  Pulmonary hypertension Clinical History:  7-year-old female with history of idiopathic pulmonary arterial hypertension on multiple medications including intravenous prostacyclin. She previously underwent an atrial septostomy for recurrent episodes of syncope, however, continued to have progressive symptoms of dyspnea, chest pain, and exercise intolerance. The child was referred for surgical placement of a Potts aortopulmonary shunt for potential improvement in her symptoms by decompressing her RV allowing for maintenance of cardiac output. She successfully underwent placement of the shunt that created an anastomosis between her left pulmonary artery and descending thoracic aorta. The procedure was considered successful in preventing  further syncopal episodes.

TEE Findings: • Postoperative TEE demonstrated mild tricuspid regurgitation with reduced RV systolic function (not shown). This was examined in the ME 4-Ch, ME RV In-Out, and TG short-axis views. • Evaluation of the Potts shunt in the Desc Ao LAX view displayed unobstructed antegrade flow from the side-to-­ side anastomosis between the left pulmonary artery and the descending aorta, resulting in a right-to-left shunt secondary to suprasystemic pulmonary arterial pressures (Fig. 20.34, Video 20.29) Discussion:  Transesophageal imaging in pulmonary hypertension is often utilized for procedural guidance during palliative interventions. During an atrial septostomy, for example, in adddition to procedural guidance, TEE allows for a detailed anatomic evaluation of the atrial communica-

tion as well as assessment of the directionality of intracardiac shunting post procedure. Evaluation of RV function is essential in these cases and in addition to a qualitative determination, the study should consider the use of the methods as previously  discussed in this chapter, but not limited to the measurement of fractional area change and tricuspid annular plane systolic excursion.  In the case presented, TEE was instrumental as an intraoperative monitor of a high-risk patient undergoing a high-risk procedure, and to document patency and direction of flow across the aortopulmonary connection.

Suggested Reading/References 1. Gorbachevsky SV, Shmalts AA, Barishnikova IY, Zaets SB. Potts shunt in children with pulmonary arterial hypertension: institutional experience. Interact Cardiovasc Thorac Surg. 2017;25:595–9.

Case #3 Subject:  Atrial myxoma Clinical History:  7-year-old male presented to the emergency room with a history of left sided paresthesias, which progressed to numbness and acute gait changes. Brain imaging  revealed evidence of multiple ischemic lesions. Comprehensive evaluation demonstrated a left atrial mass occupying much of the left atrium and prolapsing through the mitral valve into the LV during diastole. Given the location of the mass, the evidence of embolic stroke and ongoing risk of further embolic stroke, the patient was taken to the operating room for removal  of the tumor. The mass was excised and the pathology was found to be consistent with a left atrial myxoma. He recovered well and the left-sided weakness improved over time with rehabilitation.

664

R. M. Friesen and L. T. Young

a

b

Fig. 20.35  Case #3. Left atrial myxoma as depicted in a ME 4-Ch view during systole (panel a) and as it prolapses into the left ventricle (LV) during diastole (panel b)

TEE Findings: • Preoperative ME 4-Ch view a displayed a large, heterogeneous mass with mobile ‘frond-like’ borders within the LA (Fig. 20.35, Video 20.30) • The mass appeared to be attached to the atrial septum and protruded across the mitral valve into the LV during diastole (Fig. 20.35, Video 20.30). • The tumor was resected and postoperative imaging demonstrated no residual mass. There was no significant mitral valve regurgitation and no evidence of atrial level shunting. Good biventricular systolic function was documented (not shown). Discussion:  Although myxomas are the most common primary cardiac tumor in adults, they may also be seen in children. A frequent presentation of atrial myxomas, as was shown by this case, is ischemic embolization. Transesophageal echocardiography is helpful in the characterization of cardiac tumors and defining their location, size and general features of the mass, as well as any secondary effects such as obstruction to inflow or outflow. While in most cases preoperative TTE imaging is diagnosic and is able to direct therapy, when surgical management is indicated, preoperative TEE can define specific attachments of the tumor and full extent of the mass, and further assess hemodynamic impact. Intraoperative imaging can therefore be quite helpful in guiding the surgical intervention and documenting successful removal of the cardiac tumor while minimizing risk to surrounding structures.

Suggested Reading/References 1. Bielefeld KJ, Moller JH.  Cardiac tumors in infants and children: study of 120 operated patients. Pediatr Cardiol. 2013;34:125–8.

Case #4 Subject:  Thrombotic complication related to implanted ventricular assist device Clinical History:  12-year-old child with a complex medical history consisting of corrected transposition and pulmonary atresia. Past history significant for initial shunt palliation, followed by Mustard-­Rastelli operation and subsequent pacemaker placement. He developed severe systemic ventricular dysfunction and underwent HeartWare VAD implantation. Device artifact and poor windows had not allowed for adequate transthoracic studies to be obtained.  During a cardiac catheterization procedure for hemodynamic assessment and device setting adjustments, TEE assessment was undertaken.

TEE Findings: • ME 4-Ch view depicts findings consistent with the anatomy of ventricular inversion with the systemic LV to the right of the patient and the RV to the left (Fig.  20.36, Video 20.31). Note the presence of a catheter across the left-sided tricuspid valve into the RV. There is a striking large echogenic mass along the apex of the LV that appears to be associated with the VAD consistent with a thrombus. The mitral valve appears thickened and echogenic near the coaptation point. • Three-dimensional TEE (3D-TEE) imaging was performed to facilitate the further characterization of the LV thrombus, which appears to occupy a large portion of the ventricular cavity (Fig. 20.37, Video 20.32). • X-Plane imaging displaying an upper mild-low moderate amount of tricuspid regurgitation (left-sided atrioventricular valve) (Fig. 20.38, Video 20.33).

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

Fig. 20.36  Case #4. ME 4-Ch view depicts findings consistent with the anatomy of ventricular inversion, with the systemic left ventricle (LV) to the right and the anatomic right ventricle (RV) to the left of the patient respectively. There is a striking large echogenic mass along the apex of the LV (arrows) that appears to be associated with the implanted  VAD, consistent with a thrombus. Note the presence of a catheter across the patient's left-sided tricuspid valve into the RV. PVA pulmonary venous atrium, SVA systemic venous atrium

Fig. 20.37  Case #4. Three-dimensional TEE imaging to further characterize the LV thrombus, confirms that it appears to occupy a large portion of the ventricular cavity. Note the lower insertion point of the left-sided tricuspid valve onto the ventricular septum

• There was patency of the pulmonary venous baffle as assessed by ME 4-Ch 2D and color Doppler imaging (Fig. 20.39, Video 20.34). • The systemic venous baffle appear unobstructed and no other thrombi was identified. There was upper mild mitral regurgitation (systemic atrioventricular valve). Discussion:  Bleeding and thrombotic complications are among the most serious problems encountered in the care of patients with long-term VADs. Echocardiography plays

665

Fig. 20.38  Case #4. X-Plane imaging displaying tricuspid regurgitation (left-­sided atrioventricular valve). RV right ventricle, SVA systemic venous atrium

an important role in the detection of pump thrombosis as this represents a risk for stroke in this patient group. Both, TTE and TEE modalities have been used in this evaluation, however, the assessment can be challenging due to poor imaging windows resulting from prior surgical interventions, or artifacts related to the device. The use of multiplane imaging is essential to reliably exclude the presence of a thrombus or provide detailed characterization if these are identified. The 3D-TEE modality, when feasible in older children and adolescents, can provide additional diagnostic information that might impact clinical management in these cases.

Suggested Readings/References 1. Raffini L. Anticoagulation with VADs and ECMO: walking the tightrope. Hematology Am Soc Hematol Educ Program. 2017;2017:674–80. 2. Huang JY, Ignjatovic V, Sheridan BJ, et al. Bleeding and thrombotic events occur early in children on durable ventricular assist devices. Thromb Res. 2019;173:65–70.

Case #5 Subject:  Aortic pseudoaneurysm Clinical History:  16-year-old male with a history of congenital aortic valve stenosis who underwent a balloon aortic valvuloplasty as an infant. He developed progressive aortic insufficiency necessitating aortic valve replacement at 13  years of age with a bioprosthetic valve. Over time, the bioprosthetic valve developed progressive stenosis with ascending aortic dilation. To better assess his aortic dimensions he underwent a CT angiogram which revealed an irreg-

666

a

Fig. 20.39  Case #4. ME 4-Ch 2D (panel a) and color Doppler imaging (panel b) displaying patency of the pulmonary venous baffle and at least moderate mitral regurgitation. LV left ventricle, PVA 1 pulmonary

a

R. M. Friesen and L. T. Young

b

venous atrium receiving pulmonary veins, PVA 2 pulmonary venous atrium above the right-sided LV, SVA systemic venous atrium

b

Fig. 20.40  Case #5. Panel a, ME Asc Ao SAX view depicts a dilated ascending aorta (Ao) with a prominent echolucent space anteriorly representing a pseudoaneurysm (Pseudo). Panel b, the aortic root is

depicted connecting to the pseudoaneurysmal cavity through a large anterior channel by color-flow Doppler imaging

ular pseudoaneurysm (also referred to as a ‘false aneurysm’) of his ascending aorta involving his aortic root. He was scheduled to undergo  aortic root and aortic valve replacement.

• In modified ME Asc Ao LAX views (transducer angles of 145° and 125°), a thickened, bioprosthetic aortic valve is seen with an aliased systolic jet into the dilated ascending aorta (Fig. 20.41, Video 20.36). The noticeable pseudoaneurysmal cavity is again seen. • Further color Doppler interrogation in the ME Asc Ao LAX view details the defect in the aortic wall that allows for egress of blood into the pseudoaneurysmal space (Video 20.37). • 2D and 3D imaging in short- and long-axis cross-sections identifies the presence of thrombus formation in the pseudoaneurysmal cavity, outside the normal border of the ascending  aorta (Fig.  20.42, Videos 20.38, 20.39, and 20.40).

TEE Findings: • Preoperative TEE provided excellent visualization of the aortic root as well as the pseudoaneurysm. In the ME Asc Ao SAX view the dilated ascending aorta is seen with a prominent echolucent space anteriorly representing a pseudoaneurysm (Fig.  20.40, Video 20.35). The aortic root connects to the pseudoaneurysmal cavity through a large anterior channel as seen by color-flow Doppler imaging.

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

667

findings. The postbypass study allowed for assessment of the intervention (aortic root and valve replacement and provided information related to global, and in particular, regional wall motion after the coronary manipulations associated with the procedure.

Suggested Readings/References 1. Malvindi PG, van Putte BP, Heijmen RH, Schepens MA, Morshuis WJ.  Reoperations for aortic false aneurysms after cardiac surgery. Ann Thorac Surg. 2010;90:1437–43. 2. Atik FA, Navia JL, Svensson LG et al. Surgical treatment of pseudoaneurysm of the thoracic aorta. J Thorac Cardiovasc Surg. 2006;132:379–85. Fig. 20.41  Case #5. Modified ME Asc Ao LAX view shows a thickened bioprosthetic aortic valve with an aliased systolic jet into the dilated ascending aorta. The noticeable pseudoaneurysmal cavity is again seen  anteriorly (arrows). Ao ascending aorta, LA left atrium, LVOT left ventricular outflow tract

Fig. 20.42  Case #5. Imaging of the ascending aorta in a short-axis plane displays the thrombus within the pseudoaneurymal space (arrows). Ao ascending aorta

Discussion:  This case presents a patient with a history of bicuspid aortic valve with progressive dilation of the aortic root. Despite previous aortic valve replacement, the bioprosthetic valve developed significant stenosis, augmenting the aortic dilation. When it occurs, this clinical problem is more likely to be seen in older children and young adults. In this setting, TTE imaging might be suboptimal and additional imaging modalities can be considered for adequate assessment of the ascending aorta, which in some cases may include TEE, particularly if there is a question of hemodynamic significance of the associated aortic valve pathology. In this case, the preoperative TEE was able to clearly visualize the pseudoaneurysm as well as the presence of a thrombus, thereby confirming the preoperative

Questions and Answers 1. A 12-year-old female with dilated cardiomyopathy and heart failure undergoes placement of a continuous LVAD as a bridge to cardiac transplantation. Upon separation from cardiopulmonary bypass the patient is noted to have a systemic arterial oxygen saturation of 85%. Which of the following as revealed by TEE may explain the arterial desaturation a. Aortic regurgitation b. A PFO c. Tricuspid regurgitation d. Obstruction of outflow cannula Answer: b Explanation: A comprehensive pre-VAD placement TEE should include an evaluation for the presence of intracardiac shunts. Following placement, diastolic suction from the device, if a PFO is present,  can create a right-to-left shunt leading to arterial hypoxemia. Although the presence of significant tricuspid regurgitation can suggest RV dysfunction, it would not directly result in a decrease in arterial oxygen saturation. Neither aortic regurgitation nor obstruction to the device would account for arterial desaturation. 2. A 4-year-old boy with end-stage liver disease undergoes a  liver transplant with TEE monitoring. He acutely becomes bradycardic and hypotensive. TEE shows an underfilled right ventricle and further evaluation reveals a thrombus in the inferior vena cava. In which phase of the liver transplantation is this complication most likely to occur a. Induction of anesthesia b. Pre-operative phase c. Anhepatic phase d. Reperfusion phase Answer: d

668

Explanation: While fluid shifts and hemodynamic instability can occur during any of the phases of liver transplantation, the combination of electrolyte shifts, bradycardia and a thrombus in the inferior vena cava resulting in a hypovolemic right ventricle are more likely to occur during the reperfusion phase. 3. A 17-year-old with newly diagnosed Marfan syndrome with severe aortic root dilation presents to the emergency department with recent onset of chest pain. A CT scan demonstrates findings consistent with aortic dissection and surgery is undertaken. The preoperative TEE reveals a linear echodensity within the aortic lumen confirming the diagnosis. Which of the features listed is consistent with the identification of the true lumen versus that of the false lumen a. The true lumen is generally larger b. The intimal flap moves into the true lumen during systole c. The true lumen typically enlarges during systole d. Expansion of a lumen during the ‘P-wave’ on the electrocardiogram is consistent with the true lumen Answer: c Explanation. The true lumen in aortic dissection is characterized by systolic expansion, moving the intimal flap towards the false lumen. The false lumen is generally larger than the true lumen. The electrocardiographic tracing can be helpful in distinguishing systolic from diastolic flap movement. Expansion of a lumen during the ‘P-wave’ would be consistent with diastolic movement and generally less helpful in distinguishing the true from the false lumen. 4. A 3-month-old infant presents to the emergency department with new onset seizures. During the evaluation a harsh systolic murmur is noted. An echocardiogram reveals multiple, homogenous echogenic masses along the interventricular septum as well as the LV free wall with mild LV outflow tract obstruction. What would be the most likely cardiac tumor in this infant a. Myxoma b. Teratoma c. Wilms tumor d. Rhabdomyoma Answer: d Explanation: The constellation of seizures and intracardiac tumors are most likely consistent with a diagnosis of rhabdomyomas found in tuberous sclerosis. Rhabdomyomas are the most common types of primary pediatric cardiac tumors. Their typical findings on echocardiogram are

R. M. Friesen and L. T. Young

homogenous, echogenic well-circumscribed lesions in the myocardium. Wilms tumors are typically found in the heart via direct extension through the inferior vena cava. Myxomas are more frequently found in adults, typically in the left atrium, and the clinical presentation is less likely to be associated with seizures, unless there are other findings of an embolic phenomenon. Teratomas are typically more heterogenous in appearance on echocardiography and are more commonly found in the pericardial space or around the pulmonary and aortic trunks. 5. A 3-year-old girl with hypoplastic left heart syndrome, with previous stage II palliation (Glenn shunt) and heart failure has just undergone orthotopic heart transplantation. On postoperative day 1, her head and neck appear swollen. You review the postoperative TEE for any relevant clues. Which of the following is most likely to explain the current clinical findings a. LV dysfunction b. Flow acceleration at the superior vena cava anastomosis c. Flow acceleration at the aortic anastomosis d. An “hourglass” appearance within the left atrium Answer: b Explanation. The patient has clinical signs suggestive of superior vena cava obstruction. For patients undergoing heart transplantation with a bicaval anastomosis, the intraoperative TEE evaluation should include assessment of these anastomotic sites (superior and inferior vena cava) in addition to other connections. Reconstruction of the superior vena cava may be necessary in the setting of a previous Glenn shunt. Evidence of narrowing, aliased color flow, or decrease/loss of the normal phasic pattern across the vessel on postoperative TEE may point to the likely etiology. Left ventricular dysfunction may be found on postoperative TEE after heart transplantation, but would not present with isolated upper body edema. Flow acceleration at the aortic anastomosis is important to evaluate postoperatively, however is not consistent with this clinical picture. An “hourglass” appearance in the left atrium is a normal finding post transplantation as it represents the left atrial cuff used to implant the donor heart to the recipient left atrium. Note from the Editors  “As this book was going into press, it was reported by Medtronic that they had stopped the distribution and sale of the HeartWare Ventricular Assist Device (HVAD)™ System, and notified physicians to cease new implants and transition to alternative devices for all future implants. Prophylactic explantation of the pump was not recommended.”

20  Applications for Non-Congenital Heart Disease in Pediatric Patients

References

669

20. Transesophageal echocardiography for lung transplantation: a new standard of care [editorial]. J Cardiothorac Vasc Anesth. 2020;34(3):741. 1. Nicoara A, Skubas N, Ad N, et al. Guidelines for the use of trans 21. Hausmann D, Daniel WG, Mügge A, et al. Imaging of pulmonary esophageal echocardiography to assist with surgical decision-­ artery and vein anastomoses by transesophageal echocardiogramaking in the operating room: a surgery-based approach: from phy after lung transplantation. Circulation. 1992;86:II251–8. the American Society of Echocardiography in collaboration with 22. Serra E, Feltracco P, Barbieri S, Forti A, Ori C. Transesophageal the Society of Cardiovascular Anesthesiologists and the Society of echocardiography during lung transplantation. Transplant Proc. Thoracic Surgeons. J Am Soc Echocardiogr. 2020;33:692–734. 2007;39:1981–2. 2. Kirk R, Dipchand AI, Rosenthal DN, et  al. The International 23. González-Fernández C, González-Castro A, Rodríguez-Borregán Society for Heart and Lung Transplantation Guidelines for the JC, et al. Pulmonary venous obstruction after lung transplantation. management of pediatric heart failure: executive summary. Diagnostic advantages of transesophageal echocardiography. Clin [Corrected]. J Heart Lung Transplant. 2014;33:888–909. Transpl. 2009;23:975–80. 3. Zaroff J.  Echocardiographic evaluation of the potential cardiac 24. McIlroy DR, Sesto AC, Buckland MR. Pulmonary vein thrombodonor. J Heart Lung Transplant. 2004;23:S250–2. sis, lung transplantation, and intraoperative transesophageal echo 4. Stoddard MF, Longaker RA.  The role of transesophageal cardiography. J Cardiothorac Vasc Anesth. 2006;20:712–5. echocardiography in cardiac donor screening. Am Heart J. 25. Spada M, Riva S, Maggiore G, Cintorino D, Gridelli B. Pediatric 1993;125:1676–81. liver transplantation. World J Gastroenterol. 2009;15:648–74. 5. Salgado Filho MF, Siciliano A, Siciliano A, Oliveira AJ, Salgado J, 26. Vetrugno L, Barnariol F, Bignami E, et al. Transesophageal ultraPalitot I. The importance of transesophageal echocardiography in sonography during orthotopic liver transplantation: show me heart harvesting for cardiac transplantation. Rev Bras Anestesiol. more. Echocardiography. 2018;35:1204–15. 2012;62:262–8. 27. Gold AK, Patel PA, Lane-Fall M, et  al. Cardiovascular collapse 6. Angermann CE, Spes CH, Tammen AR, et  al. Transesophageal during liver transplantation-echocardiographic-guided hemodyechocardiography after orthotopic heart transplantation. Int J Card namic rescue and perioperative management. J Cardiothorac Vasc Imaging. 1990;5:271–4. Anesth. 2018;32:2409–16. 7. Romano P, Mangion JR. The role of intraoperative transesopha 28. Markin NW, Sharma A, Grant W, Shillcutt SK.  The safety geal echocardiography in heart transplantation. Echocardiogr J of transesophageal echocardiography in patients undergoing Cardiovasc Ult. 2002;19:599–604. orthotopic liver transplantation. J Cardiothorac Vasc Anesth. 8. Tan Z, Roscoe A, Rubino A. Transesophageal echocardiography 2015;29:588–93. in heart and lung transplantation. J Cardiothorac Vasc Anesth. 29. Hudhud D, Allaham H, Eniezat M, Enezate T. Safety of perform2019;33:1548–58. ing transoesophageal echocardiography in patients with oesopha 9. Morgan JA, Edwards NM.  Orthotopic cardiac transplantation: geal varices. Heart Asia. 2019;11:e011223. comparison of outcome using biatrial, bicaval, and total tech 30. Liu E, Guha A, Dunleavy M, Obarski T. Safety of transesophageal niques. J Card Surg. 2005;20:102–6. echocardiography in patients with esophageal varices [letter]. J 10. Davies RR, Russo MJ, Morgan JA, Sorabella RA, Naka Y, Chen Am Soc Echocardiogr. 2019;32(5):676–7. JM. Standard versus bicaval techniques for orthotopic heart trans 31. Dalia AA, Flores A, Chitilian H, Fitzsimons MG.  A compreplantation: an analysis of the United Network for Organ Sharing hensive review of transesophageal echocardiography during database. J Thorac Cardiovasc Surg. 2010;140:700–8, 708.e1. orthotopic liver transplantation. J Cardiothorac Vasc Anesth. 11. Ishizuka N, Nakamura K, Fujita Y, et al. Transesophageal echo2018;32:1815–24. cardiographic findings in patients after heart transplantation. J 32. Pantham G, Waghray N, Einstadter D, Finkelhor RS, Mullen Cardiol. 1997;29:163–70. KD.  Bleeding risk in patients with esophageal varices under 12. Vouhe PR, Tamisier D, Le Bidois J, et al. Pediatric cardiac transgoing transesophageal echocardiography. Echocardiography. plantation for congenital heart defects: surgical considerations and 2013;30:1152–5. results. Ann Thorac Surg. 1993;56:1239–47. 33. Spier BJ, Larue SJ, Teelin TC, et al. Review of complications in a 13. Dipchand AI, Rossano JW, Edwards LB, et  al. The registry of series of patients with known gastro-esophageal varices undergothe International Society for Heart and Lung Transplantation: ing transesophageal echocardiography. J Am Soc Echocardiogr. eighteenth official pediatric heart transplantation report--2015; 2009;22:396–400. focus theme: early graft failure. J Heart Lung Transplant. 34. Hahn RT, Abraham T, Adams MS, et al. Guidelines for performing 2015;34:1233–43. a comprehensive transesophageal echocardiographic examination: 14. del Rio MJ. Transplantation in complex congenital heart disease. recommendations from the American Society of Echocardiography Prog Pediatr Cardiol. 2000;11:107–13. and the Society of Cardiovascular Anesthesiologists. J Am Soc 15. Kirklin JK, Naftel DC, Kirklin JW, Blackstone EH, White-­ Echocardiogr. 2013;26:921–64. Williams C, Bourge RC.  Pulmonary vascular resistance and the 35. Puchalski MD, Lui GK, Miller-Hance WC, et  al. Guidelines risk of heart transplantation. J Heart Transplant. 1988;7:331–6. for performing a comprehensive transesophageal echocardio 16. Webber SA, McCurry K, Zeevi A. Heart and lung transplantation graphic examination in children and all patients with congenital in children. Lancet. 2006;368:53–69. heart disease: recommendations from the American Society of 17. Kindel SJ, Hsu HH, Hussain T, Johnson JN, McMahon CJ, Echocardiography. J Am Soc Echocardiogr. 2019;32:173–215. Kutty S.  Multimodality noninvasive imaging in the monitor 36. Nigatu A, Yap JE, Lee Chuy K, Go B, Doukky R. Bleeding risk ing of pediatric heart transplantation. J Am Soc Echocardiogr. of transesophageal echocardiography in patients with esophageal 2017;30:859–70. varices.[letter]. J Am Soc Echocardiogr. 2019;32(5):674–6. 18. Meyers BF, Lynch J, Trulock EP, Guthrie TJ, Cooper JD, Patterson 37. Isaak RS, Kumar PA, Arora H. Pro: Transesophageal echocardiogGA.  Lung transplantation: a decade of experience. Ann Surg. raphy should be routinely used for all liver transplant surgeries. J 1999;230:362–70; discussion 370. Cardiothorac Vasc Anesth. 2017;31:2282–6. 19. Essandoh M, Bhatt A, Flores A, Whitson B.  Transesophageal 38. Shillcutt SK, Ringenberg KJ, Chacon MM, et al. Liver transplanechocardiography monitoring during lung transplantation.[letter]. tation: intraoperative transesophageal echocardiography findings J Cardiothorac Vasc Anesth. 2017;31:e98–9.

670 and relationship to major postoperative adverse cardiac events. J Cardiothorac Vasc Anesth. 2016;30:107–14. 39. Siniscalchi A, Gamberini L, Bardi T, et al. Post-reperfusion syndrome during orthotopic liver transplantation, which definition best predicts postoperative graft failure and recipient mortality. J Crit Care. 2017;41:156–60. 40. Jenks CL, Raman L, Dalton HJ.  Pediatric extracorporeal membrane oxygenation. Crit Care Clin. 2017;33:825–41. 41. Thiagarajan RR, Barbaro RP, Rycus PT, et al. Extracorporeal life support organization registry international report 2016. ASAIO J. 2017;63:60–7. 42. Erdil T, Lemme F, Konetzka A, et al. Extracorporeal membrane oxygenation support in pediatrics. Ann Cardiothorac Surg. 2019;8:109–15. 43. Valencia E, Nasr VG. Updates in pediatric extracorporeal membrane oxygenation. J Cardiothorac Vasc Anesth. 2020;34:1309–23. 44. Bautista-Rodriguez C, Sanchez-de-Toledo J, Da Cruz EM. The role of echocardiography in neonates and pediatric patients on extracorporeal membrane oxygenation. Front Pediatr. 2018;6:297. 45. Garcia AV, Jeyaraju M, Ladd MR, et al. Survey of the American Pediatric Surgical Association on cannulation practices in pediatric ECMO. J Pediatr Surg. 2018;53:1843–8. 46. Napp LC, Kühn C, Hoeper MM, et al. Cannulation strategies for percutaneous extracorporeal membrane oxygenation in adults. Clin Res Cardiol. 2016;105:283–96. 47. Douflé G, Roscoe A, Billia F, Fan E. Echocardiography for adult patients supported with extracorporeal membrane oxygenation. Crit Care. 2015;19:326. 48. Irish MS, O’Toole SJ, Kapur P, et  al. Cervical ECMO cannula placement in infants and children: recommendations for assessment of adequate positioning and function. J Pediatr Surg. 1998;33:929–31. 49. Ranasinghe AM, Peek GJ, Roberts N, et al. The use of transesophageal echocardiography to demonstrate obstruction of venous drainage cannula during ECMO. ASAIO J. 2004;50:619–20. 50. Adachi I, Burki S, Fraser CD. Current status of pediatric ventricular assist device support. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2017;20:2–8. 51. Burki S, Adachi I.  Pediatric ventricular assist devices: current challenges and future prospects. Vasc Health Risk Manag. 2017;13:177–85. 52. Dipchand AI, Kirk R, Naftel DC, et al. Ventricular assist device support as a bridge to transplantation in pediatric patients. J Am Coll Cardiol. 2018;72:402–15. 53. Schweiger M, Lorts A, Conway J. Mechanical circulatory support challenges in pediatric and (adult) congenital heart disease. Curr Opin Organ Transplant. 2018;23:301–7. 54. Maeda K, Rosenthal DN, Reinhartz O. Ventricular assist devices for neonates and infants. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2018;21:9–14. 55. Schwartz BG, Ludeman DJ, Mayeda GS, Kloner RA, Economides C, Burstein S.  Treating refractory cardiogenic shock with the Tandemheart and Impella devices: a single center experience. Cardiol Res. 2012;3:54–66. 56. Parekh D, Jeewa A, Tume SC, et  al. Percutaneous mechanical circulatory support using Impella devices for decompensated cardiogenic shock: a pediatric heart center experience. ASAIO J. 2018;64:98–104. 57. Smith L, Peters A, Mazimba S, Ragosta M, Taylor AM. Outcomes of patients with cardiogenic shock treated with TandemHeart® percutaneous ventricular assist device: importance of support indication and definitive therapies as determinants of prognosis. Catheter Cardiovasc Interv. 2018;92:1173–81.

R. M. Friesen and L. T. Young 58. Dimas VV, Morray BH, Kim DW, et al. A multicenter study of the Impella device for mechanical support of the systemic circulation in pediatric and adolescent patients. Catheter Cardiovasc Interv. 2017;90:124–9. 59. Kulat BT, Russell HM, Sarwark AE, et al. Modified TandemHeart ventricular assist device for infant and pediatric circulatory support. Ann Thorac Surg. 2014;98:1437–41. 60. Chowdhury S, Chadha T, Fafard M, Shillingford M. Mechanical circulatory support using modified TandemHeart ventricular assist device in neonates with CHD. Cardiol Young. 2018;28:1361–2. 61. Ochiai Y, McCarthy PM, Smedira NG, et  al. Predictors of severe right ventricular failure after implantable left ­ventricular assist device insertion: analysis of 245 patients. Circulation. 2002;106:I198–202. 62. Sachdeva R, Frazier EA, Jaquiss RD, Imamura M, Swearingen CJ, Vyas HV. Echocardiographic evaluation of ventricular assist devices in pediatric patients. J Am Soc Echocardiogr. 2013;26:41–9. 63. Scalia GM, McCarthy PM, Savage RM, Smedira NG, Thomas JD.  Clinical utility of echocardiography in the management of implantable ventricular assist devices. J Am Soc Echocardiogr. 2000;13:754–63. 64. Horton SC, Khodaverdian R, Powers A, et  al. Left ventricular assist device malfunction: a systematic approach to diagnosis. J Am Coll Cardiol. 2004;43:1574–83. 65. Ivy DD, Abman SH, Barst RJ, et al. Pediatric pulmonary hypertension. J Am Coll Cardiol. 2013;62:D117–26. 66. Kirkpatrick EC. Echocardiography in pediatric pulmonary hypertension. Paediatr Respir Rev. 2013;14:157–64. 67. Barst RJ, Ertel SI, Beghetti M, Ivy DD. Pulmonary arterial hypertension: a comparison between children and adults. Eur Respir J. 2011;37:665–77. 68. Jone PN, Ivy DD.  Echocardiography in pediatric pulmonary hypertension. Front Pediatr. 2014;2:124. 69. Hatle L, Angelsen BA, Tromsdal A.  Non-invasive estimation of pulmonary artery systolic pressure with Doppler ultrasound. Br Heart J. 1981;45:157–65. 70. Berger M, Haimowitz A, Van Tosh A, Berdoff RL, Goldberg E. Quantitative assessment of pulmonary hypertension in patients with tricuspid regurgitation using continuous wave Doppler ultrasound. J Am Coll Cardiol. 1985;6:359–65. 71. David M, Andrew M. Venous thromboembolic complications in children. J Pediatr. 1993;123:337–46. 72. Dollery CM.  Pulmonary embolism in parenteral nutrition. Arch Dis Child. 1996;74:95–8. 73. Dutta T, Frishman WH, Aronow WS.  Echocardiography in the evaluation of pulmonary embolism. Cardiol Rev. 2017;25:309–14. 74. Bedet A, Razazi K, May F, Mekontso DA. Transesophageal echocardiography for pulmonary embolism diagnosis in the intensive care unit: artifact in three dimensions. Intensive Care Med. 2017;43:261–2. 75. Rosenberger P, Shernan SK, Body SC, Eltzschig HK.  Utility of intraoperative transesophageal echocardiography for diagnosis of pulmonary embolism. Anesth Analg. 2004;99:12–6. 76. Phoon CK, Rutkowski M. Transesophageal imaging of the mid to distal left pulmonary artery in congenital heart disease. J Am Soc Echocardiogr. 1999;12:663–8. 77. Nowak M, Shernan SK, Eltzschig HK, Rosenberger P.  A novel view for visualizing a left pulmonary artery thromboembolus with intraoperative transesophageal echocardiography. J Clin Anesth. 2008;20:136–8. 78. Klein AL, Abbara S, Agler DA, et  al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease: endorsed by the Society for Cardiovascular Magnetic Resonance

20  Applications for Non-Congenital Heart Disease in Pediatric Patients and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013;26:965–1012.e15. 79. Imazio M, Spodick DH, Brucato A, Trinchero R, Adler Y. Controversial issues in the management of pericardial diseases. Circulation. 2010;121:916–28. 80. Maisch B, Seferović PM, Ristić AD, et al. Guidelines on the diagnosis and management of pericardial diseases executive summary; The task force on the diagnosis and management of pericardial diseases of the European Society of Cardiology. Eur Heart J. 2004;25:587–610. 81. Welch TD, Oh JK.  Constrictive pericarditis. Cardiol Clin. 2017;35:539–49. 82. Dal-Bianco JP, Sengupta PP, Mookadam F, Chandrasekaran K, Tajik AJ, Khandheria BK.  Role of echocardiography in the diagnosis of constrictive pericarditis. J Am Soc Echocardiogr. 2009;22:24–33. quiz 103 83. Hatle LK, Appleton CP, Popp RL. Differentiation of constrictive pericarditis and restrictive cardiomyopathy by Doppler echocardiography. Circulation. 1989;79:357–70. 84. Oh JK, Hatle LK, Seward JB, et  al. Diagnostic role of Doppler echocardiography in constrictive pericarditis. J Am Coll Cardiol. 1994;23:154–62. 85. Garcia MJ. Constrictive pericarditis versus restrictive cardiomyopathy. J Am Coll Cardiol. 2016;67:2061–76. 86. Mahmoud A, Bansal M, Sengupta PP. New cardiac imaging algorithms to diagnose constrictive pericarditis versus restrictive cardiomyopathy. Curr Cardiol Rep. 2017;19:43. 87. Hoit BD. Pericardial disease and pericardial tamponade. Crit Care Med. 2007;35:S355–64. 88. Flachskampf FA. Assessment of aortic dissection and hematoma. Semin Cardiothorac Vasc Anesth. 2006;10:83–8. 89. Flachskampf FA, Daniel WG.  Aortic dissection. Cardiol Clin. 2000;18:807–17, ix. 90. Asfoura JY, Vidt DG.  Acute aortic dissection. Chest. 1991;99:724–9. 91. Nienaber CA, Spielmann RP, von Kodolitsch Y, et al. Diagnosis of thoracic aortic dissection. Magnetic resonance imaging versus transesophageal echocardiography. Circulation. 1992;85:434–47. 92. Matura LA, Ho VB, Rosing DR, Bondy CA. Aortic dilatation and dissection in Turner syndrome. Circulation. 2007;116:1663–70. 93. Erbel R, Bednarczyk I, Pop T, et  al. Detection of dissection of the aortic intima and media after angioplasty of coarctation of the aorta. An angiographic, computer tomographic, and echocardiographic comparative study. Circulation. 1990;81:805–14. 94. Miller DC, Mitchell RS, Oyer PE, Stinson EB, Jamieson SW, Shumway NE.  Independent determinants of operative mortality for patients with aortic dissections. Circulation. 1984;70:I153–64. 95. DeBakey ME, McCollum CH, Crawford ES, et  al. Dissection and dissecting aneurysms of the aorta: twenty-year follow-up of five hundred twenty-seven patients treated surgically. Surgery. 1982;92:1118–34. 96. Keren A, Kim CB, Hu BS, et  al. Accuracy of biplane and multiplane transesophageal echocardiography in diagnosis of typical acute aortic dissection and intramural hematoma. J Am Coll Cardiol. 1996;28:627–36. 97. Penco M, Paparoni S, Dagianti A, et al. Usefulness of transesophageal echocardiography in the assessment of aortic dissection. Am J Cardiol. 2000;86:53G–6G. 98. Nishimura RA, Otto CM, Bonow RO, et  al. 2014 AHA/ACC Guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129:e521–643. 99. Glas KE, Swaminathan M, Reeves ST, et  al. Guidelines for the performance of a comprehensive intraoperative epiaortic ultra-

671

sonographic examination: recommendations of the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists; endorsed by the Society of Thoracic Surgeons. Anesth Analg. 2008;106:1376–84. 100. Thrumurthy SG, Karthikesalingam A, Patterson BO, Holt PJ, Thompson MM. The diagnosis and management of aortic dissection. BMJ. 2011;344:d8290. 101. Goldstein SA, Evangelista A, Abbara S, et al. Multimodality imaging of diseases of the thoracic aorta in adults: from the American Society of Echocardiography and the European Association of Cardiovascular Imaging: endorsed by the Society of Cardiovascular Computed Tomography and Society for Cardiovascular Magnetic Resonance. J Am Soc Echocardiogr. 2015;28:119–82. 102. MacKnight BM, Maldonado Y, Augoustides JG, et al. Advances in imaging for the management of acute aortic syndromes: focus on transesophageal echocardiography and type-A aortic dissection for the perioperative echocardiographer. J Cardiothorac Vasc Anesth. 2016;30:1129–41. 103. Shiga T, Wajima Z, Apfel CC, Inoue T, Ohe Y. Diagnostic accuracy of transesophageal echocardiography, helical computed tomography, and magnetic resonance imaging for suspected thoracic aortic dissection: systematic review and meta-analysis. Arch Intern Med. 2006;166:1350–6. 104. Meredith EL, Masani ND.  Echocardiography in the emergency assessment of acute aortic syndromes. Eur J Echocardiogr. 2009;10:i31–9. 105. Vignon P, Spencer KT, Rambaud G, et  al. Differential transesophageal echocardiographic diagnosis between linear artifacts and intraluminal flap of aortic dissection or disruption. Chest. 2001;119:1778–90. 106. Keane MG, Wiegers SE, Yang E, Ferrari VA, St John Sutton MG, Bavaria JE.  Structural determinants of aortic regurgitation in type A dissection and the role of valvular resuspension as determined by intraoperative transesophageal echocardiography. Am J Cardiol. 2000;85:604–10. 107. Movsowitz HD, Levine RA, Hilgenberg AD, Isselbacher EM.  Transesophageal echocardiographic description of the mechanisms of aortic regurgitation in acute type A aortic dissection: implications for aortic valve repair. J Am Coll Cardiol. 2000;36:884–90. 108. Luck SR, DeLeon S, Shkolnik A, Morgan E, Labotka R.  Intracardiac Wilms’ tumor: diagnosis and management. J Pediatr Surg. 1982;17:551–4. 109. Chan HS, Sonley MJ, Moës CA, Daneman A, Smith CR, Martin DJ.  Primary and secondary tumors of childhood involving the heart, pericardium, and great vessels. A report of 75 cases and review of the literature. Cancer. 1985;56:825–36. 110. Roberts WC. Primary and secondary neoplasms of the heart [editorial]. Am J Cardiol. 1997;80(5):671. 111. Shapiro LM. Cardiac tumours: diagnosis and management. Heart. 2001;85:218–22. 112. Miyake CY, Del Nido PJ, Alexander ME, et  al. Cardiac tumors and associated arrhythmias in pediatric patients, with observations on surgical therapy for ventricular tachycardia. J Am Coll Cardiol. 2011;58:1903–9. 113. Niwa K, Tashima K, Terai M, Okajima Y, Nakajima H. Contrast-­ enhanced magnetic resonance imaging of cardiac tumors in children. Am Heart J. 1989;118:424–5. 114. Link KM, Lesko NM.  MR evaluation of cardiac/juxtacardiac masses. Top Magn Reson Imaging. 1995;7:232–45. 115. Bardo DM.  Cardiac magnetic resonance imaging signal characteristics of cardiac tumors in children. J Am Coll Cardiol. 2011;58:1055–6. 116. Beroukhim RS, Prakash A, Buechel ER, et  al. Characterization of cardiac tumors in children by cardiovascular magnetic reso-

672 nance imaging: a multicenter experience. J Am Coll Cardiol. 2011;58:1044–54. 117. Obeid AI, Marvasti M, Parker F, Rosenberg J.  Comparison of transthoracic and transesophageal echocardiography in diagnosis of left atrial myxoma. Am J Cardiol. 1989;63:1006–8. 118. Geibel A, Kasper W, Keck A, Hofmann T, Konstantinides S, Just H. Diagnosis, localization and evaluation of malignancy of heart and mediastinal tumors by conventional and transesophageal echocardiography. Acta Cardiol. 1996;51:395–408. 119. Engberding R, Daniel WG, Erbel R, et  al. Diagnosis of heart tumours by transoesophageal echocardiography: a multicentre study in 154 patients. European Cooperative Study Group. Eur Heart J. 1993;14:1223–8. 120. Brown AS, Why H, Monaghan MJ.  Value of multiplane transoesophageal echocardiography in recurrent atrial myxoma. Br Heart J. 1994;71:540. 121. Borges AC, Witt C, Bartel T, Müller S, Konertz W, Baumann G.  Preoperative two- and three-dimensional transesophageal echocardiographic assessment of heart tumors. Ann Thorac Surg. 1996;61:1163–7. 122. Goldman JH, Foster E. Transesophageal echocardiographic (TEE) evaluation of intracardiac and pericardial masses. Cardiol Clin. 2000;18:849–60. 123. Uzun O, Wilson DG, Vujanic GM, Parsons JM, De Giovanni JV. Cardiac tumours in children. Orphanet J Rare Dis. 2007;2:11.

R. M. Friesen and L. T. Young 124. Günther T, Schreiber C, Noebauer C, Eicken A, Lange R. Treatment strategies for pediatric patients with primary cardiac and pericardial tumors: a 30-year review. Pediatr Cardiol. 2008;29:1071–6. 125. Madueme P, Hinton R. Tuberous sclerosis and cardiac rhabdomyomas: a case report and review of the literature. Congenit Heart Dis. 2011;6:183–7. 126. Becker AE.  Primary heart tumors in the pediatric age group: a review of salient pathologic features relevant for clinicians. Pediatr Cardiol. 2000;21:317–23. 127. Burke AP, Rosado-de-Christenson M, Templeton PA, Virmani R.  Cardiac fibroma: clinicopathologic correlates and surgical treatment. J Thorac Cardiovasc Surg. 1994;108:862–70. 128. Jones JP, Ramcharan T, Chaudhari M, et al. Ventricular fibromas in children, arrhythmia risk, and outcomes: a multicenter study. Heart Rhythm. 2018;15:1507–12. 129. Reynen K. Cardiac myxomas. N Engl J Med. 1995;333:1610–7. 130. Bulkley BH, Hutchins GM. Atrial myxomas: a fifty year review. Am Heart J. 1979;97:639–43. 131. Pérez de Isla L, de Castro R, Zamorano JL, et al. Diagnosis and treatment of cardiac myxomas by transesophageal echocardiography. Am J Cardiol. 2002;90:1419–21. 132. Burke A, Johns JP, Virmani R.  Hemangiomas of the heart. A clinicopathologic study of ten cases. Am J Cardiovasc Pathol. 1990;3:283–90.

Applications in the Cardiac Catheterization and Electrophysiology Laboratories

21

Peter R. Koenig and Paul Tannous

Abbreviations 3D Three-dimensional ACHD Adult congenital heart disease ASD Atrial septal defect ASO Amplatzer septal occluder AV Atrioventricular CHD Congenital heart disease CT Computed tomography IVC Inferior vena cava LV Left ventricle MRI Magnetic resonance imaging PDA Patent ductus arteriosus PFO Patent foramen ovale RV Right ventricle SVC Superior vena cava TEE Transesophageal echocardiography TTE Transthoracic echocardiography VSD Ventricular septal defect Key Learning Objectives • Understand the importance of communication in the interventional cardiology suite • Understand the role of TEE in interventions to close septal defects • Understand the role of TEE in valve interventions • Understand the role of TEE in septal defect creation

Electronic supplementary material The online version of this chapter (https://doi.org/10.1007/978-­3-­030-­57193-­1_21) contains supplementary material, which is available to authorized users. P. R. Koenig (*) · P. Tannous Northwestern University Feinberg School of Medicine, Chicago, IL, USA e-mail: [email protected]; [email protected]

 pplications in the Cardiac Catheterization A and Electrophysiology Laboratories

Introduction Since the first percutaneous pulmonary valve intervention performed by Rubio-Alvarez in 1953 [1], the breadth of diagnostic and interventional procedures performed via cardiac catheterization continues to expand. On one end of the spectrum, children are brought to the laboratory within minutes after birth for urgent, life-saving interventions. On the other end is a rapidly growing population of adult congenital heart disease (ACHD) patients who typically have unique anatomic and physiologic considerations. Across this spectrum the primary imaging modality for invasive studies has long been fluoroscopy, but there is an ever-increasing appreciation for the deterministic and stochastic injuries related to radiation exposure, for both the patient and procedural staff. This is particularly concerning in the management of patients with congenital heart disease (CHD), as the youngest children may be more sensitive to ionizing radiation and are likely to undergo multiple lifetime procedures. Similarly, concerns are high in ACHD patients who, given the typical body habitus and case complexity, may experience significant radiation exposure. Commensurate with the As Low As Reasonably Achievable (ALARA) principle, the interventional field is rapidly expanding the use of ancillary imaging modalities to complement and even replace fluoroscopic-­ based guidance. The techniques and advantages of transesophageal echocardiography (TEE), as outlined in this textbook, have proven to be an asset in providing such complimentary imaging and reduction of total radiation dose [2, 3]. TEE provides detailed, real-time imaging in children as small as 3 kg. It has complementary and at times superior anatomic delineation than transthoracic echocardiography (TTE), mainly for pos-

© Springer Nature Switzerland AG 2021 P. C. Wong, W. C. Miller-Hance (eds.), Transesophageal Echocardiography for Pediatric and Congenital Heart Disease, https://doi.org/10.1007/978-3-030-57193-1_21

673

674

Fig. 21.1  3D image of a cardioform ASD occluder as viewed from the left atrium as it sits on the atrial septum. Note that with this highly cropped still frame, orientation to other structures may be lost

Fig. 21.2  Fusion imaging example, using a VesselNavigator™ system for overlay Glenn anastomosis post left pulmonary artery (LPA) stent placement. Two light blue rings were digitally placed at the proximal and distal ends of a LPA stenosis to aid in precise stent placement. In addition, a small veno-venous collateral is filled with contrast from the left innominate vein to the left sided pulmonary veins. Although this is not an echocardiographic image overlaying the fluoroscopic views of the thorax, this illustrates how multimodality imaging can be linked, potentially with echocardiographic imaging. RPA  right pulmonary artery, SVC superior vena cava

terior structures and heart valves. It also does not require endovascular access and thus avoids the relatively large venous sheath necessary for intracardiac echocardiography. Furthermore, TEE maintains the sterile field and minimally interferes with fluoroscopy or the interventional procedure itself [2, 4].

P. R. Koenig and P. Tannous

Improvements in TEE imaging have progressed from single plane, to biplane, and now multiplane imaging with workable real-time three-dimensional (3D) capture. Probe miniaturization has enabled TEE imaging in increasingly smaller pediatric patients. With these advances, the use of TEE in children in the diagnosis and management of CHD has greatly increased. The applications and benefits of TEE during congenital heart surgery have been well described [5– 8], particularly in the intraoperative setting. Similarly, this imaging modality can be incorporated into the interventional cardiac catheterization laboratory without significant additional risk to the patient or need for capital investment. The information gained can be used to further define the cardiac anatomy; in turn, this information may change the conduct of the cardiac catheterization (e.g., may demonstrate that the intended intervention is not necessary or needs modification). TEE has the additional unique role of being able to guide cardiac interventions in a continuous fashion [9]. Guidance may involve placement of catheters, wires or pacing catheters [4, 10]. It may also guide the creation or enlargement of an interatrial communication [11–14], balloon angioplasty [10, 12], dilation or stent insertion of a narrowed area [3, 4, 10–12, 15], or for closure of defects in the interatrial or interventricular septum [2, 15–20]. Other defects that can be occluded include patent ductus arteriosus (PDA), aortopulmonary collaterals, coronary artery fistulae, aortopulomonary shunts (eg. Blalock Taussig shunts), Fontan fenestrations or other baffle or patch leaks, as well as defects not necessarily congenital in nature such as perivalvar leaks, the left atrial appendage, or dissections using covered stents. However, many of these interventions do not typically use TEE for guidance. In addition to the above, there are emerging technologies incorporating TEE which have the potential of significant improvements in guiding procedures. Two promising technologies include 3D TEE as well as fusion imaging (Figs. 21.1 and 21.2). Three-dimensional echocardiography is increasingly used in pediatrics and congenital heart imaging [21, 22]. This technology has been transferred to a TEE platform as well as intracardiac echocardiography [21, 22]. Indeed, this technology has been used to aid in imaging CHD and guiding interventions, especially atrial septal defect (ASD) and patent foramen ovale (PFO) closure [23, 24]. However, 3D TEE is not yet widely used in pediatrics (and CHD) interventions due to the size of the probe. This is actively changing with probe miniaturization, image refinement, and physician familiarity. Fusion imaging, whereby noninvasive images such as an MRI, CT or echocardiograms are superimposed on an angiographic image, also has great potential to aid interventions and reduce the ionizing radiation burden [23, 25, 26]. Although there are other imaging modalities (TTE and intracardiac echocardiography) that can be used during cardiac catheterization or electrophysiologic studies (as dis-

21  Applications in the Cardiac Catheterization and Electrophysiology Laboratories

cussed below), this chapter is specifically dedicated to the applications of TEE, with a review of the most common ­procedures performed in patients with CHD.  Although the descriptions of the particular techniques used may vary, an effort is made to describe those that have been broadly applied at most institutions.

Communication Between Teams General Concepts Interventional procedures represent a situation where human error and breakdown in communication can result in devastating effects, and the principles of Crew Resource Management as used for airline safety are easily transferrable to the laboratory. Throughout the entire procedure, clarity in communication is paramount, and all members of the team should feel empowered to immediately express any safety concerns. Use of common language, a shared understanding of the case plan and anticipated course, and familiarity between the operating and imaging teams should help mitigate risk in even the most complex of cases. Echocardiography for interventional cases can be divided into pre-procedural, intra-procedural and post-procedural imaging. The imaging team (typically an echocardiographer and assisting sonographer) should have a thorough understanding of the initial cardiac anatomy, prior interventions, and what the latest noninvasive imaging has shown (with a personal review of those images) prior to entering the catheterization suite. The TEE study is thus directed to review any relevant anatomy as well as obtain baseline findings, usually using a protocol, which may be based on recent guidelines for TEE imaging [27]. Once this is completed, TEE is used to guide the specific procedure with frequent checks and rechecks as well as monitoring for any significant changes (pericardial effusion, device embolization, etc.). After completion of the procedure, TEE is used to focus on the relative success of the procedure (e.g. ASD occlusion, nonrestrictive ASD after defect creation, etc.), and any adverse sequelae (e.g. encroachment of a device on a valve) or emergent findings (new pericardial effusion, embolization, etc.). Many times, the TEE repeats the initial survey to reestablish the new baseline. The latter survey can be abbreviated.

Pre-Procedural Communication (“Time-Out”) Prior to starting the procedure, there should be a huddle between the imaging and interventional teams in which members are introduced and roles assigned. There should then be a review of the indication for procedure, anticipated sequence of events, the intended intervention, and possible complications, with as much detail as is needed for clear

675

communication later in the case. Both the echocardiographer and interventionalist should have reviewed the prior imaging data (ideally together), and discuss when and how the echocardiographer will be collaborating with the interventionalist during the procedure. The imaging team should have a general understanding of the planned approach (e.g., if there will be catheters introduced from the internal jugular vein into the superior vena cava so there is no time wasted to find a catheter being advanced from the inferior vena cava), the  essential information the operator requires to make a decision before committing to an intervention, and what complications can be anticipated and thus monitored during the case.

Intra-Procedural Communication During the procedure there should be on-going communication between the imaging and interventional teams. Communication is improved if the teams are able to effectively use the same language in anatomic terms, a process that can sometime be clouded given the interventionalist’s biplane fluoroscopic view versus the echocardiographer’s two-dimensional slice of cardiac anatomy. Echocardiographic imaging planes are different than those used for axial imaging planes–as may be seen with computed tomography (CT) or magnetic resonance imaging (MRI)–and this can result in different terms being  used by the interventionalist as compared to  the echocardiographer. An example of this is that even with the standard position of the heart in the chest, the anterolateral papillary muscle is not truly anterior. It could be posterior to the posteromedial papillary muscle (Fig. 21.3). In addition, the heart may be in a different location on its axis—mesocardia, dextrocardia, etc. Thus, terms should be used that are universal or at least clearly understood to mean the same thing by the echocardiographer and interventionalist. This becomes especially important when closing defects [24, 28]. Specific views and terms used in TEE imaging are discussed in section “Specific Applications of TEE During Interventions for Congenital Heart Disease”, based upon the  American Society of Echocardiography Guidelines for Performing a Comprehensive Transesophageal Echocardiographic Examination in Children and All Patients with Congenital Heart Disease [27]. The other central tenet of communication during procedures is to ensure each provider has situational awareness of the other’s actions so as to understand the current state and anticipate the next move. Sometimes this is announcing “I am deploying the left atrial disc…” or simply to agree on who is moving at any given moment. What cannot occur is simultaneous movement/sweeps by both the interventionalist and echocardiographer, as this renders communication largely ineffective and the teams end up working in a parallel rather than collaborative manner.

676

a

Fig. 21.3  This illustrates the concept of understanding tomographic planes in 3D space and subjective impression as the latter may influence communication if those communicating are not using the same terms to describe anatomy in 3D space. This example uses transthoracic echocardiography (TTE) and MRI to demonstrate the concept as the imager has a better understanding or 3D space with a TTE by looking at the probe position on the chest. (With TEE, it is even more difficult for the imager to understand actual 3D relationships of images in the chest). (a) Shows a transthoracic parasternal short axis image with the red line demonstrating a possible subjective impression of anterior and posterior as the image is actually obtained with the probe anteriorly on the chest. However, the true anterior and posterior plane is closer to the blue

P. R. Koenig and P. Tannous

b

c

line. This is more clearly seen in (b) with a corresponding MRI which shows the true anterior and posterior axis in the sagittal plane (blue line). (c) Shows the likely tomographic plane of the TTE image (white line) in a coronal MRI tomographic plane. Note that the usual terms “posteromedial papillary muscle” and “anterolateral papillary muscle” might  not be accurate as the papillary muscles may be on the same anterior/posterior level in 3D space. Perhaps the terms superior and inferior papillary muscles may be more accurate in this case. A anterior, P posterior, RV right ventricle, LV left ventricle, MPM medial papillary muscle, LPM lateral papillary muscle, S superior, I inferior, M medial or midline, L lateral and leftward

Post-Procedural Communication Following any intervention there should be an immediate focused TEE reassessment. Based on the pre-case huddle the imaging team should have a checklist of items to re-evaluate. There will be imaging of items specific to the device or procedure performed (such as re-measuring gradients or assessing device position and surrounding anatomy), as well as an evaluation of complications such as excluding interval development of a pericardial effusion. In many cases the post-­ procedural assessment is protocol-driven, but the imaging and interventional teams should discuss if there are any specific concerns unique to the case that need to be addressed. Fig. 21.4 Radiofrequency ablation procedure facilitated by

 pecific Applications of TEE During S Interventions for Congenital Heart Disease

TEE. Midesophageal bicaval view with color Doppler imaging demonstrating puncture (arrow) of a Fontan baffle (F) in a patient with complex heart disease consisting of dextrocardia, double inlet left ventricle and pulmonary atresia, to facilitate an electrophysiologic procedure. A Atrium

Electrophysiologic Studies Given its superb imaging of posterior atrial anatomy, TEE may be called upon to guide procedures during electrophysiologic studies. Applications include guidance during pacing catheter placement, selective access of the coronary sinus [29, 30], as well as real-time imaging during transseptal puncture [30, 31]. These TEE applications are similar in the

pediatric and adult population undergoing invasive electrophysiologic evaluation. However, in patients with congenital heart lesions and altered anatomy, catheter placement may require unusual locations which can be well-imaged via the transesophageal approach as shown in Fig. 21.4 [32, 33]. The most common use of TEE in the practice of electrophysiology is in the management of atrial fibrillation (AF). The

21  Applications in the Cardiac Catheterization and Electrophysiology Laboratories

2014 guidelines for management of atrial fibrillation mandate that in the absence of three weeks of therapeutic systemic anticoagulation, TEE should be performed to screen for thrombus prior to all procedures if the patient has been in AF for more than 48 h or for an unknown duration [34].

Valve Procedures TEE has been utilized during valvuloplasty of stenotic valves. Although it has been applied to procedures involving all cardiac valves, most of the experience in children relates to mitral [35–37], aortic [38], and pulmonary valves [12, 15]. Triscupid valve dilations are rarely performed. The use of pre-procedural TEE in these settings might be more important in delineating the anatomy of valvar structures, measuring the valve annulus, and evaluating associated subvalvar or supravalvar obstruction [12, 15]. In addition, TEE facilitates the evaluation of associated lesions and global cardiac function. During a valve intervention, TEE may allow for guidance of proper wire, catheter, and balloon position to prevent entanglement with valvar apparatus or important surrounding structures [3, 10]. In cases of radiofrequency perforation of the pulmonary valve, TEE, in conjunction with fluoroscopy, facilitates the procedure by confirming wire/catheter position, documenting when valve perforation occurs, and monitoring the catheter as it is successfully advanced across the newly perforated atretic pulmonary valve. TEE is extremely valuable in the assessment of the results of the intervention and exclusion of potential complications such as pericardial effusion or injury to other valves [3, 10]. The main issues to be addressed following an intervention are residual valvar obstruction and the presence and severity of regurgitation. TEE is particularly helpful in this assessment and provides detailed information without the need for any additional contrast or radiation exposure. The imaging views used before, during, and after valve procedures are similar to those described for a diagnostic TEE study (Chaps. 4, 9, and 13) and as noted throughout this textbook. The focus of the examination should be on the relevant pathology. Hemodynamics should be evaluated in imaging planes able to achieve Doppler alignment parallel to blood flow. TEE does not have a documented role in standard transcatheter pulmonary valve replacement procedures (Melody or Sapien valve), and there are currently no pediatric indications for transcatheter aortic valve replacement. TEE has been reportedly useful in non-conventional valve delivery. In a small case series of 5 patients weighing 99% of all cases. Although intracardiac echocardiography may be utilized during ASD occlusion [44], TEE remains the main imaging approach for guiding these procedures at many institutions and is often preferred in smaller children to minimize the risk of vascular injury. The above protocol and images for ASD occlusion are  mainly for 2D TEE. However, 3D imaging of the atrial septum may allow a better understanding of the size, shape and location of the ASD [24, 45]. It may be possible to perform much of the procedure with 3D TEE and thus reduce the need for

21  Applications in the Cardiac Catheterization and Electrophysiology Laboratories

a

b

c

d

681

e

Fig. 21.9  9 year old male with a moderate size secundum atrial septal defect (ASD) diagnosed via transthoracic echocardiography, who was brought to the cardiac catheterization suite. After obtaining an initial TEE to confirm the anatomy and show that ASD closure was indicated and feasible, the closure procedure commenced with the following sequence of transcatheter occlusion of the secundum ASD. The ASD occluder for this patient was an Amplatzer® septal occluder device. (a) TEE image in a hybrid midesophageal aortic valve short axis/fivechamber view demonstrating a guide wire (arrow) crossing the interatrial septum through an ASD during transcatheter device occlusion.

(b) Following guidewire placement across the ASD, well into the left atrium/pulmonary vein, a sheath (arrow) is advanced across the ASD as shown in this midesophageal four-­chamber view. (c) After deployment of the left atrial disc of occluder device (arrow), (d) the right disk (arrow) is opened. Note the appearance of the waist between the two discs. (e) After the occluder has been released, the position of the device relative to surrounding structures should be evaluated. As demonstrated in this midesophageal four-­chamber view, there should be no impingement of the device on the atrioventricular valves. AV aortic valve, LA Left atrium, LV left ventricle, RA right atrium, RV right ventricle

682

P. R. Koenig and P. Tannous

a

Fig. 21.10  The push pull maneuver to evaluate  Atrial Septal Defect Occluder device  stability, using a midesophageal bicaval view. The device sheath is pulled back (withdrawn) as seen in (a), followed by

a

b

pushing back (advanced) in the other direction as in (b). LA Left atrium, RA right atrium, D device

b

Fig. 21.11  Deployment of the Gore Cardioform Septal Occluder®. The initial steps for defect sizing and wire position are identical for the Amplatzer Septal Occluder and Cardioform devices. (a) Shows a modified midesophageal aortic valve short axis view with the device appearance as it is initially deployed in the left atrium. As the left atrial disc

forms the device is then opposed to the atrial septum, followed then by right atrial disc deployment. (b) Demonstrates final position and lay of the device with capture of retro-aortic and posterior rims shown. Trace residual flow through device leaflets is expected and normal. Red lines depict degree of shift during “locking” step device deployment

fluoroscopy [46]. Figure 21.12 shows the 3D TEE appearance of an occluded secundum ASD as viewed from the right atrium, as well as a 3-D video clip of a secundum ASF pre and post occlusion (Videos 21.1 and 21.2).

or outflow obstruction not amenable to relief), severe left ventricular dysfunction, necessity for left atrial decompression in patients who are receiving circulatory support, or in patients with severe pulmonary vascular disease and pulmonary hypertension who require a “pop off” atrial right to left shunt [15, 47–50]. Balloon atrial septostomy has been traditionally performed under fluoroscopic guidance [51]. However, echocardiographic monitoring has offered the ability to display pertinent anatomic structures, and this in principle should decrease the risk of the procedure. Bedside balloon atrial septostomy using TTE has been well described [47, 48]. Most centers use fluoroscopy, TTE, or both for pro-

 reation or Enlargement of an Atrial C Communication Creation or enlargement of an interatrial communication may be required in patients with the following: transposition physiology (to enhance mixing of systemic and pulmonary venous return), severe inflow restriction to one of the ventricles (either due to inflow obstruction, ventricular hypoplasia,

21  Applications in the Cardiac Catheterization and Electrophysiology Laboratories

a

b

c

d

683

Fig. 21.12  Shows 3D appearance of an ASD occluder (d) with the corresponding 2D images (a–c). A motion clip of a secundum ASD is shown in Videos 21.1, with the corresponding appearance of the

occluder after deployment in Video 21.2. RA right atrium, LA left atrium, D occluder device

cedural guidance. TEE has also been applied in this setting and offers the benefit of continuous monitoring while ­maintaining a sterile field and avoiding interference with the intervention [2, 4, 10]. TEE can be particularly useful when attempting to create or enlarge an interatrial communication in individuals with unusual anatomy or small atria [15]. Similar to closure of ASDs, TEE is initially utilized to confirm the anatomy and disclose any new anatomic, hemodynamic or other important findings (e.g., thrombus in a patient with severe myocardial dysfunction). After this assessment, it is used to guide/confirm wire and catheter placement, demonstrate balloon position and the appearance of the latter prior to the septostomy. It can then be used to monitor the actual procedure and adequacy of the result. Based on the information acquired, it can be determined whether or not the procedure needs to be repeated, modified, or abandoned.

The typical views used include the ME 4-Ch view (to image the atrial septum, atria and AV valves), as well as the ME Bicaval view to demonstrate the interatrial septum, caval veins, and atrial appendages in a sagittal (or modified) plane. Rapid, frequent alternations between these two planes, as well as modified planes, are usually required to maintain visualization of the catheter and septostomy balloon. The intraprocedural communication between the echocardiographer and interventionalist mentioned above is especially important during this procedure to help avoid inadvertent injury to nearby structures or hemodynamic compromise. Figure 21.13 demonstrates a sequence of events during TEE guided atrial septostomy. In infants with hypoplastic left heart syndrome and an intact atrial septum, an emergent procedure to decompress the left atrium can be undertaken in the cardiac catheterization laboratory under combined TEE and fluoroscopic

684

P. R. Koenig and P. Tannous

a

b

c

d

Fig. 21.13  Balloon atrial septostomy with TEE guidance in a newborn infant with double outlet right ventricle and mitral atresia. There were signs of pulmonary venous congestion and a TEE was performed to guide atrial septostomy. In figure (a), a patent foramen is shown with flow from the left to right atrium (arrow, blue jet). (b) Shows a septos-

tomy sheath (arrow) in a left pulmonary vein (PV). (c) Shows the septostomy balloon (B) after inflation in the left atrium and withdrawal across the atrial septum. (d) Shows the appearance of the much larger atrial septal defect (arrow) after balloon atrial septostomy. LA left atrium, RA right atrium

guidance. Given the small left atrium and distorted, often thickened atrial septum in this lesion, echocardiographic imaging is particularly helpful to guide a wire, transseptal needle or radiofrequency catheter placement in creating a perforation across the interatrial septum. The remainder of the intervention is aimed at creating an adequate outlet for the left atrium by balloon dilation of the de novo defect.

In cases in which a septostomy procedure is (a) unsuccessful, (b) determined likely to be so, or (c) not considered the most favorable approach, a stent may be placed across the interatrial septum and balloon dilated to achieve a similar result. This might be necessary, for example, in young infants with a thick interatrial septum or small atria, conditions less amenable to standard balloon atrial septostomy. The procedure is similar to that described above for creation of an ASD, with similar imaging planes. This sequence of events

21  Applications in the Cardiac Catheterization and Electrophysiology Laboratories

a

b

c

d

e

f

Fig. 21.14  Shows TEE imaging during of the atrial septum followed by stent placement. This is a 2 month old infant with previously undiagnosed {S,L,L} segmental anatomy, double inlet left ventricle and left atrioventricular valve atresia. The atrial level communication was restrictive and the TEE was used to guide enlargement of the interatrial communication and placement of an interatrial stent. Figure (a) is a midesophageal four-chamber view showing a small interatrial communication (arrow) by  2D imaging. The same view is used in (b) with color Doppler. The same view is again seen in (c), now with a guidewire

685

(arrow) across the atrial septum. The guidewire is used to place a sheath (arrow) as seen in (d). A stent is deployed through the sheath and is dilated in the atrial communication as seen in figures (e, f), showing the stent (arrow) in a midesophageal aortic valve short axis view and then the stent is seen in a midesophageal right ventricular inflow-outflow view in (g) though the view is applied to a different anatomy as this is a single ventricle. (h) Shows the same image as e and  f, with color Doppler demonstrating no evidence of obstruction across the newly dilated defect (arrow). LA left atrium, RA right atrium

686

g

P. R. Koenig and P. Tannous

h

Fig. 21.14 (continued)

a

b

c

Fig. 21.15  Placement of left ventricular venting catheter in a teenager with a dilated cardiomyopathy (severe left ventricular dysfunction) on extracorporeal membrane oxygenation (ECMO) who was noted to have pulmonary edema with severe left atrial and ventricular dilation. The TEE was used to guide placement of a ventricular vent. Figure (a) is a midesophageal four-chamber view with attention to the interatrial septum to demonstrate indentation of the interatrial septum (arrow) towards the left atrium by a needle prior to transseptal puncture. Figure (b) is a

modified midesophageal bicaval view (transducer angle 129°), with injection of agitated saline “bubble” contrast to confirm position of a catheter tip within the left atrium prior to further interventions. Figure (c) is a midesophageal four-chamber view demonstrating placement of a left ventricular venting catheter through the interatrial septum and across the mitral valve into the left ventricle. LA left atrium, LV left ventricle, RA right atrium, RAA right atrial appendage, RV right ventricle, SVC superior vena cava

21  Applications in the Cardiac Catheterization and Electrophysiology Laboratories

demonstrating atrial septal defect stenting is shown in Figs. 21.14 and 21.15.

 ranscather Occlusion of Ventricular Septal T Defects Transesophageal imaging of a ventricular septal defect (VSD) is described in Chap. 10. Transcatheter closure of VSDs has been well described [15, 18, 19]. Currently, only muscular and perimembranous VSDs are potentially amenable to transcatheter device closure (as opposed to the other types of VSDs, see Chap. 10) [28]. At the time of this writing, the only device approved in the United States for closure of muscular VSDs is the Amplatzer® muscular VSD occluder (St. Jude Medical, St. Paul, MN). Similar to the transcatheter closure of ASDs, in order to understand the manner in which TEE may guide VSD closure procedures, it is appropriate to review the steps involved. The description that follows applies to the use of the Amplatzer® device. The Amplatzer® muscular VSD occluder is designed specifically for the muscular septum. The waist of the device, which centers and fills the defect, measures 7 mm in length. The left and right ventricular disks are 8 mm larger than the connecting waist in all but the smallest size device. Various occluder sizes are available, ranging from device size/waist diameter of 4 mm (corresponding disk diameter of 9 mm) to device size/waist diameter of 18  mm (corresponding disk diameter of 26 mm). These muscular defects can be closed using percutaneous or perventricular techniques. Although percutaneous closure of a single muscular VSD is feasible without TEE guidance, many centers consider that TEE provides information not readily available by fluoroscopy, such as the relationship between the device, the AV valve leaflets and subvalvar apparatus, and the aortic valve. These structures can be seen using TEE imaged views as noted below. Prior to occluder release, a comprehensive survey should be performed to ensure the device is not distorting or compromising the function of any essential structures. For multiple defects (“Swiss cheese septum”), TEE is considered mandatory to identify the location of the defects, the relationship of these to surrounding structures, and to enhance the overall safety and success of the intervention. Routine right and left heart catheterization is performed to assess the degree of shunting, evaluate the pulmonary vascular resistance, and perform angiography to define the location, size, and number of ventricular communications. A complete TEE study is undertaken from the standard ­imaging locations (Chaps. 4 and 10). The AV valves are interrogated at baseline for evidence of regurgitation, as these can potentially be altered during device placement. Any associated cardiovascular abnormalities should be characterized and gross assessment of chamber size and ventricular function should be made. Specific attention is then paid to the VSD(s) and nearby structures, including the aortic and AV valves, papillary muscles, moderator band, and chordae tendineae.

687

The views that allow for assessment of the ventricular septum (as well as surrounding anatomy) are similar as those given in Chap. 10, with a focus on the views that optimally demonstrate the defect to be closed. Specific views for imaging the location, size, and number of VSDs include the ME 4-Ch, ME 5-Ch, midesophageal long axis (ME LAX), midesophageal aortic valve long axis (ME AoV LAX), ME AoV SAX, ME RV In-Out, deep transgastric 5 chamber (DTG 5-Ch), deep transthoracic right ventricular outflow tract (DTG RVOT), the transgastric basal short axis (TG Basal SAX), transgastric mid papillary short axis (TG Mid Pap SAX), and transgastric apical short axis (TG Apical SAX) views. In general, many views may be applicable for a given defect, and with trial and error, the best ones for a given patient are chosen to help guide the procedure. The outflow views are better suited for defects near the membranous septum, while the inflow views are better suited for demonstrating muscular VSDs. The appropriate device size is chosen to be 1–2 mm larger than the VSD size as assessed by TEE or angiography at end-­ diastole (the larger of the two diameter estimates). The next step in the closure sequence is to place a sheath across the defect. This is accomplished in a variety of ways. The most common approach used for mid-muscular VSD device closure is to advance a catheter via retrograde catheterization from the left ventricle (LV) across the VSD into the right ventricle (RV). An exchange wire is advanced through the VSD and the RV into either branch pulmonary artery or retrograde through the tricuspid valve into the superior vena cava. In the latter case the wire is then snared and exteriorized through the right internal jugular vein. This provides a stable arteriovenous loop and allows a sheath to be advanced over the wire, from the right jugular vein to the RV and positioned into the LV across the VSD. Larger mid-muscular or apical VSDs can be easily crossed from the RV. However, there is an increased risk of entrapment in the trabeculae of the RV. Once the catheter crosses into the LV, an exchange guide wire is positioned into the LV apex and a delivery sheath is advanced over this wire and positioned into the body of the chamber. TEE and angiography are helpful in guiding device position. The LV disk is deployed in the middle of the LV cavity. Then, the entire assembly (cable/sheath) is pulled towards the interventricular septum with further retraction of the sheath to expand the waist within the VSD. Repeat TEE and angiography confirm device position. Assessment of mitral valve function is essential prior to deployment of the RV disk. It is important to assess the device position in multiple planes. Once proper position is confirmed, further retraction of the sheath to expand the RV disk is performed. Again, prior to device release, repeat TEE and angiography are performed. After deployment, TEE imaging allows for confirmation of device placement, assessment of residual shunting and/or any obstruction or regurgitation induced by the device. With release of the device and elimination of all tension, the device orientation frequently changes, which allows it to align with the ven-

688

P. R. Koenig and P. Tannous

a

b

c

d

Fig. 21.16  Shows the sequence of transcatheter occlusion of a muscular ventricular septal defect (VSD). Figure (a) is a TEE 2D and color Doppler midesophageal four-chamber view demonstrating a muscular VSD (arrow) near the apex of the heart. The sequential steps in the procedure include: after a guidewire placement across the defect, a catheter/sheath (arrow) is placed over the guidewire and positioned with the tip in an appropriate location in the left ventricle as in (b). After

placement, the guidewire is withdrawn and the occluder is advanced in the sheath and the left disc (arrow) is opened in the left ventricle as in (c). This is followed by opening of the right disc (arrow) in the right ventricle and then release of the device as shown in (d). The position of the device after deployment is then assessed as it sits on the ventricular septum (S).Video 21.3 is a movie clip of the occluder deployment. LV left ventricle, RV right ventricle

tricular septum. If there are any additional defects, they are occluded in similar fashion. Illustrative TEE images are shown in Fig. 21.16 and Video 21.3. In some cases, due to patient size and associated safety concerns related to percutaneous closure or if the muscular VSD is within the context of additional malformations requiring surgical repair, device closure of the ventricular communication can be achieved in the operating room [52] or hybrid cath lab (perventricular closure). Similar to the cardiac catheterization lab, an initial complete TEE assessment of the ventricular septum is performed. If the muscular VSD is the only defect, the procedure can be performed without placement of the cardiopulmonary bypass cannulae; if there are associated malformations requiring cardiopulmonary bypass, cannulation may be performed. However bypass is not initiated until after occlusion of the VSD. TEE images for a typical procedure are shown in Fig. 21.17. An 18-gauge needle is used to puncture the right ventricular free wall aiming towards the VSD, as assessed by TEE, which may also be used to demonstrate the indentation over the right ventricular free wall by the needle prior to puncture. This will help determine the path of the guidewire (and later sheath) and provide information on entrapment

of the AV valve apparatus or a pathway obstructed by the moderate (or other) muscle bands. A short guide wire is passed through the needle to the VSD into the LV. Over this wire, a proper size sheath and dilator are advanced into the LV. After dilator removal, a proper size device is advanced inside the delivery sheath under TEE guidance until the left disk is deployed in the LV. The entire assembly (cable and sheath) is then pulled towards the septum, followed by retraction of the sheath over the cable in order to deploy the connecting waist and right disk. If satisfactory position is achieved as documented by TEE, the device is released. The same procedure can be repeated for multiple VSDs. As in the case of closure in the cardiac catheterization laboratory, TEE imaging is performed post device placement to ensure closure of the intracardiac communication. Color Doppler is essential in this assessment for evaluation of residual shunting around the device and for any potential procedural complications. During these interventions, TEE allows for continuous monitoring of cardiac volume and function, and optimization of hemodynamics. It is important to consider that moderate to large defects and co-­existent pathology can result in elevated pulmonary artery and right ventricular pressures.

21  Applications in the Cardiac Catheterization and Electrophysiology Laboratories

a

689

b

c

Fig. 21.17  Perventricular, hybrid closure of ventricular septal defect (VSD). Figure shows midesophageal four-chamber views demonstrating the sequence of events associated with perventricular closure of a muscular VSD in the operating room as a hybrid approach by the interventionalist and surgeon. Following sternotomy, the right ventricular free wall is exposed. (a) Shows an indentation of the RV free wall and needle puncture (arrow) near a muscular VSD (asterisk). Following

wire and sheath placement into the left ventricle the occluder device is advanced and the left disc of the occluder (arrow) is delivered as shown in (b). After opening of the right ventricular disk the position of the device is documented and the device is released as seen in (c). Note the appearance of the occluder waist (arrow) at the defect and the minimal space for the right ventricular disc. LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

Therefore, the post device placement exam should explore not only the potential for residual left-to-right shunting but also right-to-left ventricular level shunting either around the device or through additional VSDs. In some cases, closure of a larger

interventricular communication might  unmask additional smaller defects. A device developed specifically for transcatheter membranous VSD closure (Amplatzer membranous VSD

690

occluder; AGA Medical Corporation, Golden Valley, MN) has undergone a number of investigations and although the initial clinical experience was encouraging [53], this device has been associated with an increased risk of complications, including complete AV block. A redesigned device has been developed to prevent conduction abnormalities (Amplatzer® membranous VSD occluder 2; St. Jude Medical, St. Paul, MN) and is currently undergoing investigation. As of this writing, this device is not yet approved for clinical use in the United States or European Union.

Baffle Interventions, Closure and Creation  losure of Fontan Fenestrations or Baffle Leaks C The use of transcatheter occlusion techniques to close fenestrations or baffle leaks in a Fontan connection has been well described [20]. Representative TEE images of this sequence are demonstrated in Fig.  21.18. Although TEE has been shown to be of benefit during these interventions, in many cases the procedures have been performed only with fluoroscopy and angiography. However patients with unusual or complicated cardiac anatomy can present unique challenges, making TEE a requirement for procedural guidance. This may also be the case in settings in which precise intracardiac anatomic information is necessary (for example, if the leak is near a margin of the patch closure of an AV valve) [20]. TEE has also been useful in guiding pre and post-­operative hemodynamics with purse string closure of a Fontan fenestration [4]. For both leaks and fenestrations, the use of a biplane or multiplane TEE probe has allowed visualization of the anatomy in two or more planes to provide the interventionist a better understanding of the 3D anatomic relation and how to conduct the procedure. The primary imaging planes used are the ME 4-Ch and ME Bicaval views. Frequent alternation between these two views allows the echocardiographer to visualize the structures of interest and help guide the procedure. Modifications of these planes are frequently required with varying locations of the defect. The goal of TEE imaging is to display the defect perpendicular to the imaging plane in two different viewing angles, to ensure appropriate deployment of an occluder device. Other intra-­ atrial baffle leaks, namely those involving Senning and Mustard connections, can be approached in a similar fashion using views such as those shown in Fig. 21.19.

 EE for Guidance of Dilation of Other T Congenital Heart Lesions Pathology associated with intracardiac baffles (Fontan, Senning, Mustard, Rastelli) is adequately visualized by angiography (similar to valve dilation procedures). However,

P. R. Koenig and P. Tannous

TEE allows for continuous monitoring of interventions associated with baffle obstruction to help guide wire, balloon, and/or stent to the appropriate area. This has been described in cases of Mustard baffle obstruction [4, 10, 11] as well as obstruction of the left ventricular to aortic pathway in an individual with a history of a prior Rastelli procedure [15]. In addition, because of its excellent imaging of the pulmonary veins, TEE can guide pulmonary vein dilation as has been described previously [51]. Suitable TEE views for enlargement of baffle narrowing are similar to those used for closure of fenestrations and/or leaks, namely the ME 4-Ch and ME Bicaval views, with appropriate use and modification of additional planes as required. These modifications are made to obtain the optimal imaging plane(s), which ideally should be orthogonal to the area of narrowing. Complementary deep transgastric views may be helpful.

Summary This chapter has provided an overview of the use of TEE during catheter-based interventions in the cardiac catheterization laboratory, operating room setting, and electrophysiologic studies. The benefits of TEE in providing procedural guidance, assessing the success of interventions, identifying complications, and overall enhancing the safety of the procedures, have been highlighted to document the applications of this imaging approach during interventions for CHD. Acknowledgements  1. Alan Nugent MD (Ann and Robert H. Lurie Children’s Hospital of Chicago) for images for catheterization, fusion imaging and muscular VSD closure images. 2. Lindsay Griffin MD (Ann and Robert H. Lurie Children’s Hospital of Chicago) for MRI images. 3. Sanket Shah MD  (Children’s Mercy Hospital, Kansas City, MO) for 3-D imaging. 4. Sandhya Ramlogan  MD (Ann and Robert H.  Lurie Children’s Hospital of Chicago)—3-D movie images.

Questions and Answers 1. Which 2D TEE views are most useful for imaging an ASD during an ASD closure intervention? a. Midesophageal bicaval b. Deep transgastric five-chamber c. Deep transgastric atrial septal d. a and c e. All of the above Answer: d

21  Applications in the Cardiac Catheterization and Electrophysiology Laboratories

a

b

c

d

e

f

Fig. 21.18  Occlusion of a Fontan fenestration. Figure (a) is a midesophageal four-chamber 2D image demonstrating a Fontan fenestration (arrow) in a patient with an unbalanced atrioventricular septal defect, status post lateral tunnel Fontan (F) procedure. In figure (b), a corresponding color Doppler interrogation demonstrates right-to-left shunting across the fenestration (blue jet noted by arrow) allowing for egress of blood from the systemic venous side of the Fontan baffle to the pulmonary venous circulation as blood enters the common atrium. The steps during Amplatzer® device occlusion of the Fontan fenestra-

691

tion as monitored by TEE imaging are illustrated as follows: (c) shows a guide wire across the fenestration in the lateral tunnel (arrow); a sheath across the defect is shown in (d). Figure (e) shows the occluder device after deployment of the left and right discs. (f) Shows the fenestration after device release; and (g) shows color Doppler interrogation post Amplatzer® occluder device placement demonstrating no residual shunting across the fenestration. A or LA functional pulmonary venous atrium, LV left ventricle, RV right ventricle

692

P. R. Koenig and P. Tannous

Explanation: The  deep transgastric atrial septal views, along with mid esophageal four chamber (ME 4-Ch), mid esophageal aortic valve short axis (ME AoV SAX), and mid esophageal bicaval (ME Bicaval) views, are useful for ASD closure. The deep transgastric five-chamber view is better for VSDs. 2. True or False. Communication between the interventionalist is to occur only during the time of the intervention. Answer: False Explanation: Communication should occur at all points of the procedure.

g

3. Which 2D TEE views are most useful for demonstrating a muscular VSD during a planned closure intervention? a. Midesophageal four chamber view b. Midesophageal five chamber view c. Transgastric basal short axis view, d. Transgastric mid papillary short axis view

Fig. 21.18 (continued)

a

b

c

Fig. 21.19  Occlusion of baffle leak following Mustard atrial baffle procedure. Figure (a) is a TEE modified midesophageal view demonstrating a defect in the atrial baffle (arrow) that divides the systemic venous atrium (SVA) from the pulmonary venous atrium (PVA) in a patient with d-transposition of the great arteries following a prior Mustard operation. The defect measures approximately 7.2 mm. Prior

to occlusion of the defect a sheath is placed across this region (arrow), to allow for the delivery shaft that carries the occluder to be advanced into the pulmonary venous atrium as shown in (b). (c) Demonstrates the position of the device to occlude the leak using an Amplatzer® atrial septal defect occluder (arrow)

21  Applications in the Cardiac Catheterization and Electrophysiology Laboratories



e. Transgastric apical short axis view f. a and c g. All of the above

Answer: g Explanation: The above views are typically the ones used for muscular VSDs. While there are other views which may demonstrate a muscular VSD, some of these views are better for showing other types of VSDs. 4 . 2D TEE has a role in the following interventions. a. ASD stenting b. Stenting of a coarctation of the aorta c. ASD occlusion d. a and c e. All of the above Answer: d Explanation: While TEE can sometimes visualize a coarctation of the aorta, it is not a typical application as a reliable method to guide this intervention. 5. Which of the following are correct concerning pulmonary valvuloplasty and the role of TEE during the intervention? a. It provides information on other structures and relative hemodynamics b. It reliably provides clear detail of a patent ductus arteriosus c. It may provide information on complications such as perforation and tamponade. d. a and c e. All of the above Answer: d Explanation: While TEE can show a patent ductus arteriosus, the anatomy of this structure is not always reliably seen. However, TEE can show shunting across a patent foramen ovale, or cardiac dysfunction as well as a pericardial effusion if perforation occurs. 6. Which answer best describes the role of 3D TEE during ASD closure? a. It is widely available for use in children as small as 3 kg b. Its use may decrease fluoroscopy time c. The imaging provided has a resolution equivalent to 2D TEE d. Its use has universally eliminated the need for fluoroscopy e. None of the above Answer: b

693

Explanation: The use of 3D is increasing but not universally available, and only for larger patients > 20 kg  until smaller probes are developed. The resolution continues to improve but is not equivalent to 2D. Its utility is in the ability to better delineate structures in 3D space.

References 1. Rubio-Alvarez V, Limon R, Soni J.  Valvulotomias intracardiacas por medio de un cateter. Arch Inst Cardiol Mex. 1953;23:183–92. 2. van der Velde ME, Perry SB, Sanders SP. Transesophageal echocardiography with color Doppler during interventional catheterization. Echocardiography. 1991;8:721–30. 3. Tumbarello R, et  al. Usefulness of transesophageal echocardiography in the pediatric catheterization laboratory. Am J Cardiol. 1993;71:1321–5. 4. Douglas DE, Fyfe DA.  Use of miniature biplane transesophageal echocardiography during pediatric atrial catheter interventional procedures. Am Heart J. 1996; https://doi.org/10.1016/ S0002-­8703(96)90407-­X. 5. Ayres NA, et  al. Indications and guidelines for performance of transesophageal echocardiography in the patient with pediatric acquired or congenital heart disease: a report from the Task Force of the Pediatric Council of the American Society of Echocardiography. J Am Soc Echocardiogr. 2005; https://doi. org/10.1016/j.echo.2004.11.004. 6. Bengur AR, et  al. Intraoperative transesophageal echocardiography in congenital heart disease. Semin Thorac Cardiovasc Surg. 1998;10:255–64. 7. Stevenson JG. Role of intraoperative transesophageal echocardiography during repair of congenital cardiac defects. Acta Paediatr Suppl. 1995;410:23–33. 8. Randolph GR, et  al. Intraoperative transesophageal echocardiography during surgery for congenital heart defects. J Thorac Cardiovasc Surg. 2002; https://doi.org/10.1067/mtc.2002.125816. 9. Khalid O, Koenig P.  The use of echocardiography in congenital heart surgery and intervention. Expert Rev Cardiovasc Ther. 2006;4:263–71. 10. Stümper O, et  al. Transesophageal echocardiographic monitoring of interventional cardiac catheterization in children. J Am Coll Cardiol. 1991;18:1506–14. 11. Tong AD, et  al. Interventional cardiac catheterization under transesophageal echocardiographic guidance. Am Heart J. 1995;129:827–31. 12. Cheung YF, Leung MP, Lee J, Yung TC. An evolving role of transesophageal echocardiography for the monitoring of interventional catheterization in children. Clin Cardiol. 1999;21:804–10. 13. Walayat M, Cooper SG, Sholler GF. Transesophageal echocardiographic guidance of blade atrial septostomy in children. Catheter Cardiovasc Interv. 2001;52:200–2. 14. Mahajan A, Shabanie A, Laks H.  Interatrial septostomy under transesophageal echocardiography guidance: a novel approach. J Thorac Cardiovasc Surg. 2002;123:824–6. 15. Van Der Velde ME, Perry SB. Transesophageal echocardiography during interventional catheterization in congenital heart disease. Echocardiography. 1997;14:513–28. 16. Rigby ML.  Transoesophageal echocardiography during interventional cardiac catheterisation in congenital heart disease. Heart. 2001;86(Suppl 2):II23–9. 17. Mazic U, Gavora P, Masura J. The role of transesophageal echocardiography in transcatheter closure of secundum atrial septal defects by the Amplatzer septal occluder. Am Heart J. 2001;142:482–8. 18. van der Velde ME, Sanders SP, Keane JF, Perry SB, Lock JE.  Transesophageal echocardiographic guidance of trans-

694 catheter ventricular septal defect closure. J Am Coll Cardiol. 1994;23:1660–5. 19. Carminati M, et  al. Transcatheter closure of congenital ventricular septal defect with amplatzer septal occluders. Am J Cardiol. 2005;96:52–8. 20. Moore JW, Murdison KA, Baffa GM, Kashow K, Murphy JD.  Transcatheter closure of fenestrations and excluded hepatic veins after fontan: versatility of the Amplatzer device. Am Heart J. 2000;140:534–40. 21. Handke M, et  al. Transesophageal real-time three-dimensional echocardiography methods and initial in vitro and human in vivo studies. J Am Coll Cardiol. 2006;48:2070–6. 22. Silvestry FE, Kadakia MB, Willhide J, Herrmann HC.  Initial experience with a novel real-time three-dimensional intracardiac ultrasound system to guide percutaneous cardiac structural interventions: a phase 1 feasibility study of volume intracardiac echocardiography in the assessment of patients with structural heart disease undergoing percutaneous transcatheter therapy. J Am Soc Echocardiogr. 2014;27:978–83. 23. Simpson J, et al. Three-dimensional echocardiography in congenital heart disease: an expert consensus document from the european association of cardiovascular imaging and the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30:1–27. 24. Silvestry FE, et al. Guidelines for the echocardiographic assessment of atrial septal defect and patent foramen ovale: from the american society of echocardiography and society for cardiac angiography and interventions. J Am Soc Echocardiogr. 2015;28:910–58. 25. Jone P-N, et  al. Echocardiography-fluoroscopy fusion imaging for guidance of congenital and structural heart disease interventions. JACC Cardiovasc Imaging. 2019; https://doi.org/10.1016/j. jcmg.2018.11.010. 26. Jone P-N, et al. Feasibility and safety of using a fused echocardiography/fluoroscopy imaging system in patients with congenital heart disease. J Am Soc Echocardiogr. 2016;29:513–21. 27. Puchalski MD, et  al. Guidelines for performing a comprehensive transesophageal echocardiographic: examination in children and all patients with congenital heart disease: recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019;32:173–215. 28. Lopez L, et  al. Classification of ventricular septal defects for the eleventh iteration of the international classification of diseases— striving for consensus: a report from the international society for nomenclature of paediatric and congenital heart disease. Ann Thorac Surg. 2018;106:1578–89. 29. Goldman AP, Irwin JM, Glover MU, Mick W.  Transesophageal echocardiography to improve positioning of radiofrequency ablation catheters in left-sided Wolff-Parkinson-White syndrome. Pacing Clin Electrophysiol. 1991;14:1245–50. 30. Kantoch MJ, Frost GF, Robertson MA.  Use of transesophageal echocardiography in radiofrequency catheter ablation in children and adolescents. Can J Cardiol. 1998;14:519–23. 31. Tucker KJ, et al. Transesophageal echocardiographic guidance of transseptal left heart catheterization during radiofrequency ablation of left-sided accessory pathways in humans. Pacing Clin Electrophysiol. 1996;19:272–81. 32. Drant SE, Klitzner TS, Shannon KM, Wetzel GT, Williams RG. Guidance of radiofrequency catheter ablation by transesophageal echocardiography in children with palliated single ventricle. Am J Cardiol. 1995;76:1311–2. 33. Hatala R, et al. Radiofrequency catheter ablation of left atrial tachycardia originating within the pulmonary vein in a patient with dextrocardia. Pacing Clin Electrophysiol. 1996;19:999–1002. 34. January CT, et  al. 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation. J Am Coll Cardiol. 2014;64:e1–e76.

P. R. Koenig and P. Tannous 35. Spevak PJ, et al. Balloon angioplasty for congenital mitral stenosis. Am J Cardiol. 1990;66:472–6. 36. Park SH, Kim MA, Hyon MS.  The advantages of on-line transesophageal echocardiography guide during percutaneous balloon mitral valvuloplasty. J Am Soc Echocardiogr. 2000;13:26–34. 37. Goldstein SA, Campbell AN.  Mitral stenosis. Evaluation and guidance of valvuloplasty by transesophageal echocardiography. Cardiol Clin. 1993;11:409–25. 38. Bourgault C, et al. Usefulness of Doppler echocardiography guidance during balloon aortic valvuloplasty for the treatment of congenital aortic stenosis. Int J Cardiol. 2008;128:30–7. 39. Gupta A, Kenny D, Caputo M, Amin Z.  Initial experience with elective perventricular melody valve placement in small patients. Pediatr Cardiol. 2017;38:575–81. 40. Essandoh M, et al. Prosthetic mitral perivalvular defect occlusion with multiple amplatzer devices using 3D transesophageal echocardiography and fluoroscopic guidance. J Cardiothorac Vasc Anesth. 2015; https://doi.org/10.1053/j.jvca.2014.10.001. 41. Quader N, Davidson CJ, Rigolin VH. Percutaneous closure of perivalvular mitral regurgitation: how should the interventionalists and the echocardiographers communicate? J Am Soc Echocardiogr. 2015; https://doi.org/10.1016/j.echo.2015.02.004. 42. Silvestry FE, et al. Guidelines for the echocardiographic assessment of atrial septal defect and patent foramen ovale: from the American Society of Echocardiography and Society for Cardiac Angiography and Interventions. J Am Soc Echocardiogr. 2015;28:910–58. 43. Ludomirsky A.  The use of echocardiography in pediatric interventional cardiac catheterization procedures. J Interv Cardiol. 1995;8:569–78. 44. Koenig PR, Abdulla R, Cao Q-L, Hijazi ZM. Use of intracardiac echocardiography to guide catheter closure of atrial communications. Echocardiography. 2003;20:781–7. 45. Faletra FF, et al. Revisiting anatomy of the interatrial septum and its adjoining atrioventricular junction using noninvasive imaging techniques. J Am Soc Echocardiogr. 2019;32:580–92. 46. Jone P-N, et  al. Three-dimensional echocardiographic guidance of right heart catheterization decreases radiation exposure in atrial septal defect closures. J Am Soc Echocardiogr. 2018;31:1044–9. 47. Perry LW, et al. Echocardiographically assisted balloon atrial septostomy. Pediatrics. 1982;70:403–8. 48. Koenig PR, et  al. Balloon atrial septostomy for left ventricular decompression in patients receiving extracorporeal membrane oxygenation for myocardial failure. J Pediatr. 1993;122:S95–9. 49. Seib PM, et al. Blade and balloon atrial septostomy for left heart decompression in patients with severe ventricular dysfunction on extracorporeal membrane oxygenation. Catheter Cardiovasc Interv. 1999;46:179–86. 50. Johnston TA, Jaggers J, McGovern JJ, O’Laughlin MP.  Bedside transseptal balloon dilation atrial septostomy for decompression of the left heart during extracorporeal membrane oxygenation. Catheter Cardiovasc Interv. 1999;46:197–9. 51. Yoshii S, et  al. Transesophageal echo-guided balloon dilatation for postoperative pulmonary venous obstruction. Surg Today. 1994;24:666–8. 52. Diab KA, Hijazi ZM, Cao Q-L, Bacha EA. A truly hybrid approach to perventricular closure of multiple muscular ventricular septal defects. J Thorac Cardiovasc Surg. 2005;130:892.e1–892.e3. 53. Holzer R, et al. Transcatheter closure of perimembranous ventricular septal defects using the amplatzer membranous VSD occluder: immediate and midterm results of an international registry. Catheter Cardiovasc Interv. 2006;68:620–8. 54. Faletra FF, et al. Echocardiographic-fluoroscopic fusion imaging in transseptal puncture: a new technology for an old procedure. J Am Soc Echocardiogr. 2017;30:886–95.

Congenital Heart Disease in the Adult

22

Jeannette Lin, George Lui, and Jamil Aboulhosn

Abbreviations 2D Two-dimensional 3D Three-dimensional AVV Atrioventricular valve CHD Congenital heart disease CT Computed tomography CW Continuous wave DTG Deep transgastric D-TGA  Dextro (D)-transposition of the great arteries FDA United States Food and Drug Administration HFpEF Heart failure with preserved ejection fraction HFrEF Heart failure with reduced ejection fraction ICD Implanted cardiac defibrillator IE Infective endocarditis IV Intravenous LA Left atrium LAA Left atrial appendage LV Left ventricle

ME Midesophageal MRI Magnetic resonance imaging PET Positron emission tomography PISA Proximal isovelocity surface area PPM Permanent pacemaker PW Pulsed wave RA Right atrium RSVA Ruptured sinus of Valsalva aneurysm RV Right ventricle RVOT Right ventricular outflow tract SVC Superior vena cava TEE Transesophageal echocardiography TG Transgastric TR Tricuspid regurgitation TTE Transthoracic echocardiography UE Upper esophageal VSD Ventricular septal defect

Key Learning Objectives Electronic Supplementary Material The online version of this chapter (https://doi.org/10.1007/978-­3-­030-­57193-­1_22) contains supplementary material, which is available to authorized users. J. Lin (*) Ahmanson/UCLA Adult Congenital Heart Center, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA e-mail: [email protected] G. Lui The Adult Congenital Heart Program at Stanford, Lucile Packard Children’s Hospital and Stanford Health Care Collaboration, Division of Cardiovascular Medicine and Pediatric Cardiology, Stanford University School of Medicine, Palo Alto, CA, USA e-mail: [email protected] J. Aboulhosn Ahmanson/UCLA Adult Congenital Heart Center, Streisand/ American Heart Association Endowed Chair, Divisions of Cardiology and Pediatric Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA e-mail: [email protected]

• Recognize indications and contraindications of TEE in the adult patient • Learn how to evaluate a patient for sedation prior to TEE • Recognize common clinical scenarios requiring TEE in the adult patient

Indications for TEE in the Adult with CHD Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) are both essential diagnostic modalities in the evaluation and management of adults with congenital heart disease (CHD). Compared with infants and children, adolescent and adult patients have increased acoustic interference from lung, skin and adipose tissue, and are more likely to have a history of chest

© Springer Nature Switzerland AG 2021 P. C. Wong, W. C. Miller-Hance (eds.), Transesophageal Echocardiography for Pediatric and Congenital Heart Disease, https://doi.org/10.1007/978-3-030-57193-1_22

695

696

J. Lin et al.

Table 22.1  General indications for TEE in the adult with congenital heart disease General indication Evaluation of cardiac and aortic structure and function in situations where the findings will alter management and TTE is non-diagnostic

Intraoperative TEE

Guidance of transcatheter procedures

Specific examples (a)  Detailed evaluation of abnormalities in structures that are typically in the far field or require superior spatial resolution, such as the left atrial appendage, Fontan pathway, interatrial septum, or intracardiac baffles (b)  Evaluation of prosthetic heart valves (c)  Evaluation of paravalvular abscesses (both native and prosthetic valves) (d)  Patients on ventilators or with chest wall injuries obscuring TTE acoustic windows (e)  Patients with body habitus preventing adequate TTE imaging (a)  All intracardiac and thoracic aortic surgical procedures (b)  Used in some coronary artery bypass graft surgeries (c)  Noncardiac surgery when patients have known or suspected cardiovascular pathology which may impact outcomes or management Guiding management of catheter-­based intracardiac procedures (including septal or baffle puncture, or septal or baffle defect closure, atrial appendage obliteration, and transcatheter valve procedures)

From Hahn et al. [1], with permission from Elsevier Table 22.2  Absolute and relative contraindications to transesophageal echocardiography Absolute contraindications Unrepaired tracheoesophageal fistula Esophageal obstruction, stricture, perforation, or laceration Perforated viscus Active gastric or esophageal bleeding Esophageal tumor Poor airway control Severe respiratory depression Uncooperative, unsedated patient

Relative contraindications History of esophageal or gastric surgery History of esophageal cancer Esophageal varices or diverticulum Recent gastrointestinal bleed Active esophagitis or peptic ulcer disease Vascular ring, aortic arch anomaly with or without airway compromise Oropharyngeal pathology Severe coagulopathy Significant thrombocytopenia Cervical spine injury or anomaly Post-gastrostomy or fundoplication (limit imaging to esophageal windows) History of radiation to neck and mediastinum Barrett’s esophagus History of dysphagia Symptomatic hiatal hernia

Abstracted from Hahn et al. [1] and Puchalski et al. [3]

wall surgeries such as mastectomy, breast reconstruction, or augmentation. TEE offers superior acoustic windows given the proximity of the esophagus to the heart, and provides superior spatial resolution compared with TTE. Common indications for TEE in adults with CHD are listed in Table 22.1. The widespread availability and advancement of three-­ dimensional (3D) TEE probes and imaging software has improved the efficiency and ease of TEE in patients with CHD in general, but particularly those with complex malformations [2]. Imaging the adult with repaired or unrepaired complex CHD is often challenging, given the variability of the location and orientation of the heart and extracardiac vessels. The examiner must have in-depth knowledge of the panoply of operated and unoperated congenital ­malformations prior to performing the study, in order to locate pertinent anatomical structures and align the imaging plane to obtain optimal visualization of anatomy and flow. Review of prior imaging data, including TTE, chest radiography, cardiac computed tomography (CT), cardiac angiography, and magnetic resonance imaging (MRI), is imperative to understanding the underlying anatomy prior to undertaking TEE.  The

full use of two-dimensional (2D) and 3D echocardiography, color and spectral Doppler, and tissue Doppler facilitates the gathering of important data.

Evaluation of the Patient Prior to TEE Compared with pediatric patients, adult patients are more likely to have clinically important  contraindications to TEE. Table 22.2, which is abstracted from the most recent adult [1] and pediatric [3] TEE guidelines, lists pertinent relative and absolute contraindications to TEE. It is imperative that these risk factors for esophageal injury are recognized, and TEE is avoided in patients with absolute contraindications. In patients with relative contraindications, the operator should carefully consider the risks and benefits of the procedure in the individual patient prior to undertaking the TEE. Patients with CHD may have syndromes that predispose to obstructive sleep apnea (e.g., trisomy 21, Pierre Robin syndrome), or disease that increases the risk of esophageal injury during TEE (e.g., vascular ring). Many adults with CHD have concurrent liver disease from chronic hepatic

22  Congenital Heart Disease in the Adult

congestion. In patients with advanced cirrhosis or history of dysphagia, evaluation with upper endoscopy should be considered before a transesophageal echocardiogram is performed. Case series suggest a low rate of esophageal hemorrhage in patients with esophageal varices, but appropriate risk stratification and monitoring is nonetheless essential in such cases [4]. Bleeding complications in patients with severe coagulopathies may be potentially minimized with transfusion of blood products where appropriate. For TEEs performed outside of the operating room or catheterization laboratory, most patients receive a topical anesthetic and intravenous (IV) administration of moderate sedation as directed by the proceduralist. Management of sedation in the adult patient during TEE can be reviewed in the American Society of Echocardiography/Society of Cardiovascular Anesthesiologists guidelines for performing TEE [1]. Topical anesthesia is achieved with a local anesthetic agent (such as a spray of lidocaine with an atomization device, or by having the patient gargle and swallow or gargle and expectorate viscous lidocaine, not to exceed a maximum dose of lidocaine of 4  mg/kg). Benzocaine spray is still in use as a topical anesthetic, but carries the risk of methemoglobinemia, a rare but potentially fatal side effect. Methylene blue, the treatment for methemoglobinemia, should be immediately available in echocardiography laboratories that use benzocaine. Moderate sedation for outpatient TEE typically consists of a combination of titrated doses of a benzodiazepine and a narcotic agent. In addition to sedation, the benzodiazepine provides for an amnestic effect and the narcotic blunts the hemodynamic stimulation related to probe insertion. In this setting, the gag reflex is generally suppressed by topical anesthesia (described above). Initial selection and dosage of medications should take into account the patient’s medical history. This should include: history of liver or renal disease which could decrease clearance of the medications; chronic narcotic or benzodiazepine use which can indicate higher tolerance of these medications; illicit drug use including methadone, heroin, or stimulants; risk factors for or history of obstructive sleep apnea. An anesthesiologist should be involved in TEE procedures in patients who might be difficult to sedate due to any of the above factors. Reversal agents such as flumazenil and naloxone should be immediately available. Patients receiving any level of sedation or anesthesia should have continuous monitoring of their heart rate and rhythm, oxygen saturation, and monitoring of their blood pressure every 3–5 min by noninvasive means. Suction should be readily available to manage the patient’s secretions. Additional considerations may apply in the setting of CHD lesions associated  with significant hemodynamic disturbance, severe pulmonary hypertension, residual cyanosis, or Fontan physiology. The physiology of single ventricle patients with Fontan palliation relies on passive flow through the lungs and therefore elevated central venous pressure. A

697

low pulmonary vascular resistance is necessary for a well-­ functioning Fontan circuit. The passive pulmonary circuit results in poor filling of the single ventricle and a reduction in cardiac output relative to the normal two-ventricle state. During conscious sedation, it is important to minimize changes in systemic venous volume, as venodilation or dehydration can reduce the central venous pressure necessary to preserve flow through the pulmonary circuit. An IV line with normal saline infusing during the TEE can be helpful to maintain central venous pressure in Fontan patients who have been fasting for the TEE procedure. Similarly, hypoventilation and hypoxia can increase pulmonary vascular resistance, which overall reduces cardiac output in these individuals. Supplemental oxygen and capnography are strongly recommended. Any patient with a Fontan fenestration or residual shunt is at high risk for paradoxical embolism and therefore all lines should be flushed to avoid air bubbles. Intravenous filters may also be considered. Changes in afterload can exacerbate right to left shunts and further desaturate a patient. Short-acting medications may take longer to metabolize in some CHD patients, and patients should be adequately monitored prior to discharge. It might be prudent to ask for support from the  anesthesia  service when  performing TEE in the adult  patient with  a  Fontan  circulation. Other patients that may benefit from anesthesia support include those with unrepaired or palliated cyanotic congenital heart lesions and pulmonary hypertension associated with CHD.

Diastolic Dysfunction Heart failure with reduced ejection fraction (HFrEF) has long been recognized as a major cause of morbidity and mortality in adults with CHD [5–8]. In the past decade, there has been increased recognition of the importance of heart failure with preserved ejection fraction (HFpEF) in adults with acquired heart disease as well as CHD. The same risk factors for HFrEF can also cause HFpEF (Table  22.3). In patients with heart failure symptoms and normal or near-normal ejection fraction, careful evaluation for diastolic dysfunction should be undertaken by echocardiography. In cases where noninvasive assessment of diastolic dysfunction is equivocal, invasive hemodynamic assessment of filling pressures both at rest and with exercise may provide additional insight into the patients’ symptomatology. Echocardiographic assessment for diastolic dysfunction has been well studied in adults with acquired heart disease. Comprehensive echocardiographic evaluation of diastolic filling should include pulsed wave (PW) Doppler of mitral valve inflow, mitral valve annular tissue Doppler, evaluation of atrial sizes, pulmonary vein inflow pattern, continuous wave (CW) Doppler of the subpulmonary atrioventricular valve regurgitation jet for estimation of the pulmonary pressures (where applicable) [9]. Limited data are available to

698

J. Lin et al.

Table 22.3  Etiology of ventricular dysfunction in the adult with congenital heart disease Anatomy Systemic morphologic left ventricle

Triggers for systolic and diastolic dysfunction •  Pressure overload (sub-, supravalvular or valvular aortic stenosis, coarctation of the aorta) •  Volume overload (aortic valve regurgitation, ventricular septal defect, patent ductus arteriosus, mitral regurgitation) •  Myocardial injury (limited myocardial protection during bypass, ventriculotomy, ischemia) •  Altered myocardial architecture (noncompaction, hypertrophic cardiomyopathy) •  Altered geometry of the subpulmonary ventricle interfering with diastolic filling of the systemic ventricle (severe pulmonary regurgitation in tetralogy of Fallot) Dysfunction of the subpulmonary •  Volume overload (severe pulmonary regurgitation, atrial septal defect with large left to right shunt) morphological right ventricle •  Pressure overload (severe right ventricular outflow tract obstruction, branch pulmonary artery stenoses) •  Pressure overload (congenitally corrected transposition of the great arteries, dextro-transposition of the Dysfunction of the great arteries after atrial switch repair) morphological systemic right •  Myocardial injury by functional ischemia (single right coronary artery, supply/demand mismatch in ventricle hypertrophied systemic right ventricle) •  Pressure overload (obstruction of the bulboventricular foramen, aortic arch obstruction) Dysfunction of the systemic single ventricle •  Impaired ventricular filling after initial volume overload (Fontan) •  Myocardial injury (limited myocardial protection during bypass, ventriculotomy) •  Myocardial architecture •  Myocardial injury from chronic hypoxia (ventricular septal defect with pulmonary stenosis) Dysfunction of the cyanotic •  Pressure overload (Eisenmenger syndrome) systemic and/or subpulmonary ventricle with or without pulmonary hypertension Acquired ischemic heart disease •  Atherosclerotic cardiovascular risk factors (hypertension, hyperlipidemia, diabetes mellitus, smoking) and ventricular dysfunction •  Congenital coronary artery anomalies (anomalous origin and/or course, extrinsic compression by a dilated pulmonary artery, coronary kinking after reimplantation of coronary arteries) •  Infiltrative cardiomyopathy (sarcoid, amyloid) Dysfunction due to •  Atrial fibrillation or flutter with rapid ventricular response, intraatrial reentrant tachycardia tachyarrhythmias

guide assessment of diastolic function and filling pressures in patients with single ventricle physiology, and tissue Doppler indices and pulmonary vein Doppler parameters correlate only modestly with catheter-derived filling pressures [10]. In a small study of 15 patients, atrioventricular valve (AVV)  systolic to diastolic duration ratio (AVV S/D ratio) correlated with elevated ventricular end diastolic pressure [11]. Further studies are needed to validate echocardiographic assessment of diastolic function in patients with single ventricle physiology and a systemic right ventricle (RV).  See Chap. 5 for discussion of the echocardiography (and specfically TEE) evaluation of diastolic dysfunction.

 natomic Assessment in the Adult A Patient with Complex CHD Over the past two decades, significant improvements in CT and MRI technology have increased their utility as noninvasive imaging modalities, and decreased the use of TEE solely for the elucidation of cardiac anatomy, given the risk of sedation and the discomfort of these types of TEE exams in adults with CHD. Conventional MRI utilizes a gadolinium based contrast agent. Ferumoxytol is an iron-containing IV medication that is United States Food and Drug Administration (FDA) approved for treatment of iron-deficiency anemia, and is currently under investigation as a contrast agent for MRI. Early

experience with ferumoxytol have yielded positive results, with superior imaging of cardiac and vascular structures compared with traditional gadolinium-based contrast agents [12, 13]. The use of four-dimensional flow MRI has also improved quantification of flow and improved detection of smaller shunts not visualized by traditional MRI sequences. The presence of implantable pacemaker and defibrillators remains a relative contraindication to MRI, but has been performed safely with careful monitoring [14]. MRI-compatible pacemakers and defibrillators are also available, and should be considered in patients who require regular MRI imaging. CT imaging provides superior spatial resolution compared with MRI, and is superior for visualization of the coronary arteries in adults. As ferromagnetic metal objects such as sternal wires, coils, and valves can cause a local signal void on MRI imaging, CT may be superior for patients with extensive hardware in the chest. The ability to perform electrocardiogram (ECG)-gated imaging across the cardiac cycle, together with protocols to decrease radiation exposure, have increased the utility and minimized the risks associated with CT scanning. As TEE provides superior spatial resolution compared with TTE, TEE is particularly helpful for identification of small thrombi and baffle leaks in patients with a Fontan circulation and patients with intracardiac baffles (e.g., atrial switch procedure) as described in the next section, or where elucidation of small shunts is not well-appreciated by CT or MRI.

22  Congenital Heart Disease in the Adult

699

Thromboembolic Complications Thromboembolic complications in adults with CHD are common. The incidence of stroke is higher in adults with CHD compared to the general population [15, 16]. Risk factors include arrhythmias, residual shunts, collaterals and residual hemodynamic abnormalities. For instance, thrombosis occurs in 8–33% of Fontan patients and contribute to morbidity and mortality [17–21]. Fontan patients who present with a thromboembolic event such as a stroke or pulmonary embolus should undergo both TTE and TEE imaging. TEE is an important tool in the evaluation of the venous pathway, pulmonary arteries, pulmonary venous atrium and/ or ligated pulmonary artery stump in a Fontan patient. Thrombus is a common complication in patients with atriopulmonary Fontan (Fig. 22.1 and Video 22.1). The atriopulmonary Fontan is best viewed in the midesophageal four-chamber (ME 4-Ch) and midesophageal aortic valve short axis (ME AoV SAX) views and should be followed from the right atrium (RA) into the pulmonary artery by bringing the probe into the upper esophagus. The lateral tunnel or extracardiac Fontan is seen in short axis in the ME 4-Ch but should also be viewed in long axis in the midesophageal two-chamber (ME 2-Ch) and midesophageal bicaval (ME Bicaval) views. It is important to rule out a residual Fontan fenestration, as this can be a source of paradoxical embolus. See Chap. 11 for further discussion regarding imaging the patient with a Fontan. Residual shunts are an important risk factor for paradoxical embolus in the adult with CHD and occur in a variety of conditions including prior repair of an atrial septal defect or ventricular septal defect (VSD). Patients with dextro-­ transposition of the great arteries (D-TGA) after atrial switch operation often have baffle leaks [22]. Small baffle leaks are common, ranging from 25% to 90%, and may lead to stroke in the setting of tachyarrhythmias or pacemaker/implanted cardiac defibrillator (ICD) leads [23]. See Chap. 15 for a complete discussion of atrial switch assessment by TEE. These baffle leaks are often assessed with transthoracic imaging with a saline contrast study. However, TEE is often essential in identifying the location and size of baffle leaks (Fig. 22.2) as well as guiding percutaneous baffle leak repair. A complete scan of the atrial switch baffle begins with a transgastric IVC/Hepatic veins (TG IVC/Hep veins) view (transducer angle 90°), demonstrating the inferior limb of the systemic venous baffle to the subpulmonic left ventricle (LV) [24]. The transducer angle can then be rotated backward to 0°, and as the probe is gradually withdrawn to the ME 4-Ch view, the pulmonary venous pathway is now demonstrated as it connects to the systemic RV. Further probe withdrawal to the upper esophagus (30°–45° plane) exposes the superior limb of the systemic venous atrium. The ME Bicaval view (90° plane) provides visualization of both the inferior and superior limbs of the systemic venous baffle. With counter-

Fig. 22.1  Midesophageal four-chamber view in an adult with tricuspid atresia, status post  atriopulmonary Fontan. There is a large thrombus noted in the right atrium as well as spontaneous contrast.  AoV aortic valve, LA left atrium, RA right atrium

Fig. 22.2  Midesophageal view at 0 degrees in an adult with transposition of the great arteries, status post atrial switch operation. There is a large baffle leak with left to right flow from the pulmonary venous atrium (PVA) into the superior vena cava (SVC) limb of the atrial switch operation

clockwise probe rotation, the pulmonary venous pathway can also be seen in the ME Bicaval view. From this view, advancing toward the stomach (transducer angle of 90° to 110°), followed by gradual withdrawal of the probe to the esophagus, will also allow imaging of both the inferior and superior limbs of the systemic venous atrium using a variety of transducer angles from 0° to 90°). Baffle leaks are commonly visualized in the superior limb of the systemic venous atrium (Fig. 22.2 and Video 22.2). Finally, assessment of intracardiac thrombus is often indicated after stroke or in the setting of atrial tachyarrhythmia before cardioversion. In the normal heart, thrombus is typically assessed in the left atrial appendage (LAA). Chapter 19

700

describes the evaluation of thrombus in the LAA. However, the LAA is part of the systemic venous pathway in the patient with D-TGA and an atrial switch operation. Therefore, thrombus should also be excluded in the systemic venous atrium. Additional techniques for ruling out thrombus include using a low aliasing velocity (20–25 cm/s) to demonstrate flow within multiple trabeculations and outpouchings. Finally, measurement of the peak emptying velocity (normal >50  cm/s) is an important assessment of global contractile function of the LAA. Patients with LAA velocities less than 20 cm/s are more likely to develop thrombus and/or thromboembolic event [25]. Thrombus should also be excluded in the pulmonary venous pathway and right atrial appendage, which can be visualized in the ME Bicaval view. The transducer angle can be rotated between 0° to 90° to visualize the right atrial appendage from different planes. Knowledge of complex congenital heart anatomy is essential when undergoing comprehensive TEE in the adult with CHD.

J. Lin et al.

Fig. 22.3  Deep transgastric five-chamber view in an adult with a prior  ventricular septal defect (VSD) patch. The VSD patch has dehisced with evidence of a mobile echo density in the VSD and right ventricular (RV) outflow tract consistent with infective endocarditis. LV left ventricle

Endocarditis Transesophageal echocardiography is an essential component in the diagnosis of infective endocarditis (IE) in high-­ risk patients such as adults with CHD. However, in pediatric patients, TEE is often reserved for those patients with suspected IE in whom imaging is suboptimal (Chap. 19). Both TTE and TEE are necessary to evaluate the adult with high risk features [26]. High-risk adult patients include those with CHD, a prosthetic valve, previous endocarditis, heart failure, Staphylococcus bacteremia, and new heart block. The incidence of IE in the adult with CHD is around 1 per 1000 patient-years as compared to a yearly incidence of 3–7 per 100,000 patient-years in the general population [27–29]. Left sided heart disease, VSDs, and residual cyanotic CHD remain the most common risk factors for IE [29, 30]. Predictors for adult-onset IE include male gender, multiple congenital heart defects, prior IE, recent cardiac or medical intervention and diabetes [29, 30]. Even the small unoperated VSDs have a risk of IE that is 20 to 30 times greater than the general population [15]. An example of a large mobile mass on the RV outflow tract (RVOT) associated with a ruptured VSD patch is demonstrated in Fig. 22.3 and Video 22.3. IE associated with a VSD can be seen in midesophageal RV Inflow-Outflow (ME RV In-Out) and deep transgastric fivechamber (DTG 5-Ch) and deep transgastric RV outflow tract (DTG RVOT) views. The endothelial surface downstream from a small membranous VSD jet or residual shunt in a prior VSD patch is a vulnerable site for the development of IE. Adults with CHD often have pacemaker (PPM) and/or ICD lead implantations and TEE is far more sensitive than TTE in the diagnosis of device-related endocarditis [31]. Small fibrinous strands are common on leads. However, in

Fig. 22.4  Midesophageal four-chamber view in an adult with Ebstein’s anomaly of the tricuspid valve and a dual chamber pacemaker lead. There is a mobile echo density seen on the pacemaker lead (PPM) in the atrium consistent with infective endocarditis. RA right atrium, RV right ventricle

the setting of positive blood cultures, any new mobile echodensity on a device lead is presumed to be a vegetation. PPM and/or ICD leads should be interrogated from the superior vena cava (SVC) and RA into the RV using the ME Bicaval, ME RV In-Out, midesophageal modified bicaval tricuspid valve (ME Mod Bicaval TV), and ME 4-Ch views. Figure 22.4 and Video 22.4 demonstrate a PPM lead with a mobile mass in a patient with Ebstein’s anomaly. Even after removal of the PPM lead, it is important to re-evaluate patients with bacteremia as IE can then spread to the tricuspid valve (Fig.  22.5 and Video 22.5). The ME 4-Ch view allows for evaluation of the tricuspid valve, but it is also important to evaluate the posterior leaflet in the deep transgastric views in coronal and sagittal planes (Chaps. 4 and 9).

22  Congenital Heart Disease in the Adult

Mortality associated with IE in adults with CHD remains high with a broad range of 2–24% [27]. Risk factors for in hospital mortality are highest with emboli, presence of prosthetic material and/or intracardiac abscess [28]. The use of TEE is associated with a higher sensitivity and specificity for the diagnosis of paravalvular abscess in the adult [26]. Color flow Doppler also allows for flow to be demonstrated in and out of these abnormal echolucent areas. The ME AoV SAX and midesophageal aortic valve long axis (ME AoV LAX) views shown in Fig. 22.6 and Video 22.6 demonstrate an example of an annular abscess associated with a biopros-

Fig. 22.5  Midesophageal four-chamber imaging angled towards the right atrium (RA) and right ventricle (RV) in an adult with Ebstein’s anomaly. There is a mobile echo density seen on the tricuspid valve consistent with infective endocarditis

Fig. 22.6 Midesophageal aortic valve short axis view (left) and midesophageal aortic valve long axis view (right) demonstrate a posterior aortic root abscess associated with an aortic valve (AoV) prosthesis. Ao ascending aorta, LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

701

thetic valve in an adult. Fistulous tracts can also extend from the abscess to adjacent structures (see Chap. 19). IE associated morbidity and mortality remains high in adults with CHD. Despite early repair, vigilance with combined TTE and TEE imaging provides rapid and comprehensive diagnostic tools for the management of IE.

Prosthetic Valve TEE is an important modality for the evaluation of mechanical and biologic valves. While TEE in children is reserved primarily in the intraoperative setting, TEE in adults has wide utility in the evaluation of prosthetic valve dysfunction in the outpatient and inpatient settings as well as intraoperatively. Indications for TEE include prosthetic valve failure, paravalvular regurgitation, thromboembolic complications, and endocarditis. This section will review these indications and  corresponding TEE imaging in the adult with CHD. Chapter 19 also discusses the TEE evaluation of prosthetic valves. Bioprosthetic valve failure is typically the result of slowly progressive tissue degeneration with pannus formation, leaflet calcification, valve thickening and immobility over time. This process results in stenosis or coaptation failure with additional regurgitation. Figure 22.7 and Video 22.7 demonstrate a dysfunctional bioprosthetic tricuspid valve in a modified ME RV In-Out view (transducer angle 130°) in a patient with dextrocardia, with the TEE probe

702

J. Lin et al.

turned to the right. A bioprosthetic tricuspid valve can also be visualized in the ME 4-Ch or ME Mod Bicaval TV views. Acute bioprosthetic valve failure is rare but can be life threatening in the setting of a bioprosthetic valve in the systemic AVV position (Fig. 22.8 and Video 22.8). The systemic AVV prosthesis is best visualized in the ME 4-Ch, midesophageal mitral commissural (ME Mitral), and midesophageal long axis (ME LAX) views. Doppler interrogation of the systemic AVV prosthetic gradient is shown in Fig. 22.9 consistent with severe stenosis. Mechanical valves

are generally very durable, and dysfunction is the result of thrombus formation in the setting of poor anticoagulation compliance or other risk factors such as atrial fibrillation. Additionally, pannus or tissue ingrowth around the valve may prevent normal disk function. Figure 22.10 and Video 22.9 demonstrate valve thrombosis in a patient with congenitally corrected transposition of the great arteries in the setting of a mechanical systemic AVV.  The thrombus has  immobilized one of the disks, resulting in significant stenosis and regurgitation. Doppler interrogation of the

Fig. 22.7  Midesophageal right ventricular inflow-outflow view (transducer angle 130° due to dextrocardia) demonstrates a bioprosthetic tricuspid valve with thickened and calcified leaflets. LA left atrium, RA right atrium, RV right ventricle

Fig. 22.8  Midesophageal four-chamber view in an adult with congenitally corrected transposition of the great arteries. There is a bioprosthetic systemic atrioventricular valve that is severely thickened with significant stenosis. LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

Fig. 22.9  Spectral Doppler interrogation of the bioprosthetic systemic atrioventricular valve in the patient from Fig. 22.8 and Video 22.8

22  Congenital Heart Disease in the Adult

mechanical systemic AVV is consistent with severe stenosis (Fig. 22.11). Paravalvular regurgitation can occur with both mechanical and biologic valves and is located outside the sewing ring. It is also common after transcatheter valve interventions, particularly with transcatheter aortic valve replacement, with rates as high as 85% [32]. The incidence of paravalvular regurgitation in the mitral position has been reported as high as 32% [16, 33]. Etiologies for paravalvular regurgitation in the early postFig. 22.10  Two dimensional image and color flow Doppler as seen from a modified midesophageal long axis view in an adult with congenitally corrected transposition of the great arteries. There is a mechanical systemic atrioventricular valve with significant turbulence across the prosthesis. One of the mechanical leaflets is immobile with thrombus

Fig. 22.11 Doppler interrogation of the mechanical systemic AV valve in the patient from Fig. 22.10 and Video 22.9

703

operative period are likely related to loss of suture material [26]. However, infection should always be considered especially late after surgery. Chapter 19 discusses methods for assessing the degree of paravalvular regurgitation. Real-time 3D TEE can provide superb visualization of the location and degree of paravalvular regurgitation (Fig.  22.12 and Video 22.10). It is important to assess the circumferential extent of paravalvular regurgitation from multiple views and differentiate it from prosthetic valve regurgitation.

704

The risk of thromboembolic complications with prosthetic valves is approximately 0.5–1.7% per patients-year [34]. The rate of thromboembolism is about 1.5 to 2 times higher for mechanical valves in the mitral versus aortic position. Large thrombus is typically easily visualized with TEE. However, because of shadowing and reverberations, it may be difficult to rule out associated small clots by TEE, especially in the aortic and pulmonary positions. Prosthetic valves are one of the most important independent risk factors for the development of IE in the adult

J. Lin et al.

with CHD with an incidence rate of 4.85 per 1000 patient years [35]. There is a rising incidence of IE in transcatheter pulmonary valve replacement of approximately 3% per patient year [15, 36, 37]. As discussed above, the use of TTE with TEE is essential in the diagnosis of endocarditis in adults with CHD. However, TEE may be limited in the assessment of vegetations in the RV outflow tract due to the anterior position (Fig. 22.13 and Video 22.11) [15, 38–42]. Serial studies in patients with suspected IE in the setting of transcatheter pulmonary valve replacement is essential, as a progressively increasing pressure gradient has been seen in these patients [15]. RVOT obstruction is the most common reason for reintervention. The use of intracardiac echocardiography, CT, and/or positron emission tomography (PET) scan may be successful in detecting missed vegetation [15]. Finally, patients with extracardiac vascular grafts are at increased risk for endovascular infections [15]. The diagnosis of extracardiac graft infection is often difficult and generally requires multiple imaging modalities (TTE/TEE, MR, CT, PET).

 valuation and Guidance for Transcatheter E Interventions Transcatheter Mitral Valve Repair Fig. 22.12  Three-dimensional TEE  image in an adult with congenitally corrected transposition of the great arteries. The image displays en face view of a mechanical systemic AV valve. There is evidence of a dehiscence of the systemic AV valve noted at 2 o’clock. See also Video 22.10 Fig. 22.13 Midesophageal aortic valve short axis view (left) and midesophageal aortic valve long axis view (right) in an adult with tetralogy of Fallot and right ventricular to pulmonary artery conduit. This X-plane long and short axis image demonstrates thickening and mobile echodensities within the proximal conduit consistent with infective endocarditis. Ao ascending aorta, PA pulmonary artery, RV right ventricle

Mitral regurgitation is encountered frequently in adults with CHD, who may have connective tissue disease resulting in mitral valve prolapse or flail, ischemic cardiomyopathy from atherosclerotic coronary artery disease or coronary artery

22  Congenital Heart Disease in the Adult

705

anomalies with associated tethering of valve leaflets, or dilated cardiomyopathy due to valvular disease, resulting in mitral annular dilation (Fig. 22.14). TEE is essential in the evaluation of mitral regurgitation and determining whether the valve is suitable for repair. In symptomatic patients with primary mitral regurgitation, the American College of Cardiology/American Heart Association algorithm for management and surgical intervention depends on whether the valve is felt to be repairable, and recommends consideration for earlier surgical referral in patients likely to have a successful repair [43, 44]. Mechanisms of mitral regurgitation are classified broadly into primary and secondary regurgitation. In primary mitral regurgitation, the regurgitation is a result of a primary abnormality of the leaflets, such as prolapse or flail. In secondary mitral regurgitation, the regurgitation is due to distortion of the valvar apparatus or annulus. A commonly used alternative classification, the Carpentier classification, differentiates mitral regurgitation into three categories based on mitral valve leaflet mobility (see Table 22.4). At the time of publication, MitraClipTM (Abbot, Illinois, USA) is the only transcatheter mitral valve repair device approved by the FDA.  Among patients with heart failure and moderate to severe or severe primary or secondary mitral regurgitation, transcatheter mitral valve repair with

MitraClipTM has been demonstrated to reduce heart failure hospitalizations and decrease all-cause mortality compared with medical therapy alone in patients deemed high or prohibitively high risk for surgery [45–47]. Several annular reduction devices and transcatheter mitral valves are currently under investigation. The MitraClipTM procedure relies heavily on TEE imaging at multiple critical steps in the procedure (Fig. 22.15 and Videos 22.12, 22.13, 22.14, 22.15, 22.16, 22.17, 22.18, 22.19). A comprehensive baseline TEE is performed at the beginning of the case with the patient under general anesthesia, with a detailed assessment of mitral valve including mitral valve area, mechanism and severity of mitral regurgitation, present of systolic pulmonary vein flow reversal. Next, the delivery system is advanced from the femoral vein into the RA, and a transseptal puncture is performed under TEE guidance in the ME AoV SAX view at 40 degrees to provide anterior-posterior orientation, with X-plane to the ME Bicaval view at 90–110° to provide superior-inferior orientation. The configuration of the current delivery system requires that the transseptal puncture is 4.0–4.5 cm above the mitral valve annulus to allow proper positioning of the MitraClipTM. Once the delivery sheath is positioned across the septum, the MitraClipTM is then advanced into the left atrium (LA) under TEE guidance to avoid injury to the left

Fig. 22.14 Carpentier classification of mitral regurgitation. From Zoghbi et al. [60], reprinted with permission from Elsevier

Table 22.4  Carpentier classification of mitral regurgitation Functional type Leaflet motion Examples

Type I Normal •  Annular dilation • Leaflet perforation •  Cleft valve

Type II Increased • Prolapse • Flail

Type III (IIIa) Restricted during systole and diastole •  Leaflet thickening and/or retraction •  Chordal thickening/shortening •  Commissural fusion

(IIIb) Restricted only during systole •  Papillary muscle displacement and/or leaflet tethering

706

J. Lin et al.

a

b

c

d

e

f

g

h

Fig. 22.15 MitraClipTM procedural guidance. (a) Midesophageal mitral commissural (ME Mitral) view demonstrating a torn chord with associated regurgitation at P2. (b) 3D surgeon’s view of the mitral valve from the left atrium. The three anterior (A1, A2, A3) and posterior (P1, P2, P3) scallops are well visualized, with the aortic valve (AOV) at 12 o’clock. Prolapse of the P2 scallop is visualized. (c) 3D surgeon’s view of the mitral valve from the left atrium with color Doppler demonstrating the origin of the regurgitant jet at the P2 prolapse. (d) The MitraClipTM delivery system is visualized in the ME Mitral view (left)

with X-plane to the midesophageal long axis (ME LAX) view (right). (e) 3D surgeon’s view of the mitral valve is used to align the clip arms perpendicular to the line of coaptation. (f) MitraClipTM has been retracted to capture the mitral valve leaflets. The ME Mitral view (left) and with X-plane to the ME LAX view (right) are used to verify capture of both leaflets. (g) 3D surgeon’s view of the mitral valve showing the double-orifice mitral valve. (h) 3D surgeon’s view with color Doppler showing trace residual mitral regurgitation

22  Congenital Heart Disease in the Adult

atrial wall, and the device is positioned in the LA above the mitral regurgitation jet, perpendicular to the line of coaptation. MitraClipTM alignment is verified using both two dimensional (2D) and 3D imaging. In 2D imaging, the clip should be visualized in short axis in the ME Mitral view at 50–70°, and in the long axis with the open clip arms at the ME LAX views (120–140°). In 3D imaging, the clip arms show be perpendicular to the line of coaptation. Failure to align the clip may result in distortion of the valve leaflets and worsening of the mitral regurgitation. Once proper alignment is confirmed, the MitraClipTM is advanced below the valve leaflets, positioning is confirmed again, and then the MitraClipTM is retracted or repositioned until both leaflets are visualized resting on the clip arms in diastole. The leaflet grippers are then deployed to secure the leaflet, and the clip is closed. Prior to release of the MitraClipTM, the mitral valve regurgitation and mitral valve area are reassessed. Patients may require deployment of multiple [2–4] clips to adequately improve the mitral regurgitation, though the risk of mitral stenosis increases with additional clips.

Tricuspid Valve Tricuspid valve regurgitation (TR) is prevalent in many forms of CHD, as a primary congenital abnormality as seen in Ebstein’s anomaly or as a consequence of functional factors that result in progressive RV dilation. Additionally, TR can result from surgical, infectious, inflammatory, iatrogenic or traumatic insults [48]. Severe TR is often the result of a coaptation defect and hence a wide vena contracta (>7 mm), proximal isovelocity surface area (PISA) radius (>9  mm) and large effective regurgitant orifice area (>40 mm2) with resultant systolic flow reversal in the inferior vena cava and the hepatic veins [49]. Severe TR results in rapid pressure equalization between the RV and RA, giving the CW Doppler signal a dagger-shaped appearance. Typically the peak velocity is low in the absence of pulmonary hypertension. The clinical impact of severe TR is often slow and insidious but highly predictive of survival [50]. Tricuspid valve stenosis is less common as a primary congenital abnormality but various degrees of tricuspid annular hypoplasia are present in a small subset of patients with hypoplastic right heart syndrome or pulmonary atresia with intact ventricular septum. Carcinoid heart disease most often affects the tricuspid valve and can result in severe tricuspid leaflet thickening and restriction with resultant stenosis. Surgical interventions for treatment of tricuspid valve dysfunction vary depending on numerous factors including the underlying etiology, leaflet adequacy and annular dimensions. The most commonly performed tricuspid valve surgeries are: Kay bicuspidisation, DeVega suture annuloplasty, prosthetic annuloplasty band,

707

and tricuspid valve replacement (most often with a bioprosthesis). Unfortunately the long-term durability of tricuspid valve repair or replacement is wanting, with 30% of patients having undergone tricuspid valve repair developing recurrent severe TR and 40% of those with bioprosthetic valve replacement developing significant valve dysfunction within 5 years [51, 52]. The risk of tricuspid valve re-operation is high with mortality rates of ~10% over the past decade [51]. Transcatheter valve in valve and valve in ring replacement is increasingly being performed, using commercially available systems that are used off-label for tricuspid valve applications [53, 54]. The treatment of native tricuspid valve regurgitation is far more challenging. The use of the MitraClipTM leaflet coaptation system has demonstrated promising early outcomes with reduction in degree of TR in the majority of patients, especially those without pacemaker leads [55]. This edge-to-edge repair technique essentially results in bicuspidisation of the tricuspid valve by clipping the anterior and septal leaflets. Procedural TEE guidance for native tricuspid valve interventions begins with the pre-interventional assessment of the tricuspid valve, which should be comprehensive and include multi-planar imaging with and without color Doppler in the midesophageal and transgastric views as well as assessment of RV systolic function and hepatic venous flow pattern. Clear identification of all three native valve leaflets (anterior, septal, posterior) is of paramount importance (Fig. 22.16, see also Chap. 4). The presence of aortic or mitral prostheses, atrial or ventricular septal patches and pacemaker leads may hinder tricuspid valve visualization in the midesophageal views but the transgastric views are unhindered and can provide the clearest view of all three leaflets. During tricuspid clip placement, it is imperative that the echocardiographer identify the three tricuspid valve leaflets in order to appropriately guide alignment and then grasping, typically of the anterior and septal leaflets. The echocardiographer should be prepared to alter from midesophageal to transgastric views; typically using the midesophageal views to guide open clip advancement through the tricuspid valve orifice, the transgastric view to rotate and line up the clip, and then back to an midesophageal view for the grasping of the anterior and septal leaflets. The adequacy of leaflet capture, degree of TR reduction and potential development of tricuspid stenosis should all be assessed by TEE prior to and following clip release. It is often necessary to place multiple clips to appreciably improve TR and the risk of tricuspid stenosis does increase and should be assessed accordingly. A successful tricuspid clip intervention is one that results in at least one grade reduction in TR severity, cessation of hepatic vein systolic flow reversal, absence of tricuspid valve stenosis, and stable clip deployment (i.e. clip/s grasping two leaflets, no evidence of clip embolization).

708 Fig. 22.16  TEE views for assessment of tricuspid valve morphology for guidance of native tricuspid valve clip placement. (a and b) Midesophageal location at 0° demonstrating the anterior (AL) and septal (SL) leaflets. The posterior leaflet (PL) and coronary sinus (CS) are not readily visible. (c and d) Midesophageal location at 0° with probe retroflexion demonstrating the PL and SL, the CS is well visualized. (e and f) Midesophageal right ventricular inflow-outflow view at 60° demonstrating the AL and PL. There is significant tricuspid regurgitation noted by color flow Doppler. (g and h) Transgastric view at 50 degrees demonstrating the three tricuspid valve leaflets en face

J. Lin et al.

a

b

c

d

e

f

g

h

22  Congenital Heart Disease in the Adult

TEE guidance of transcatheter tricuspid valve in valve or valve in ring replacement is approached in a similar manner to the assessment of native tricuspid valve dysfunction, starting with clear imaging of the prosthetic or previously repaired tricuspid valve in both esophageal and transgastric multiplanar views. Bioprosthetic valve dysfunction is often associated with both regurgitation and stenosis and thrombus may be present on the valve leaflets, atrial wall or pacemaker leads. Following transcatheter valve deployment, the TEE should comprehensively assess the valve for evidence of intra or paravalvular regurgitation and for leaflet mobility. In patients with prior tricuspid valve repair using surgical annuloplasty bands or rings, transcatheter balloon sizing is often performed prior to valve placement. Echocardiographic guidance should include assessment of balloon size and the presence of systolic (and occasionally diastolic) flow around the balloon, typically this occurs at the medial aspect of an open ring, and signifies that paravalvular regurgitation will likely be present post valve deployment. TEE guidance of paravalvular leak occlusion with transcatheter plugs is often required to reduce the degree of paravalvular regurgitation [54].

709

fenestration is essential for device selection. Distances from the RSVA to the aortic valve leaflet and the nearest coronary ostium are also important in selecting device size and type. Assessment of the RV outflow tract to rule out sub-pulmonary stenosis should be performed pre and post device deployment. Following device deployment, TEE should be utilized to ensure absence of coronary ostial obstruction, presence of new or worsening aortic valve regurgitation, presence of residual flow, or presence of subpulmonary stenosis in the case of RSVA into the RVOT (Fig. 22.18).

a

b

Ruptured Sinus of Valsalva Aneurysm Ruptured sinus of Valsalva aneurysm (RSVA) is a rare complication of aneurysmal dilation of one or more aortic root sinuses of Valsalva. There are a number of potential causes of sinus of Valsalva aneurysm formation which include inherent connective tissue abnormalities, trauma, infection, and an unrepaired supracristal or perimembranous VSD with progressive herniation of an aortic sinus into a cardiac chamber (typically the right sinus of Valsalva into the RVOT, or RA, rarely the LA). Rupture of a dilated and herniated sinus of Valsalva into a cardiac chamber results in immediate continuous flow from the aortic root into a lower pressure cardiac chamber which inevitably results in volume overload; depending on the size of the shunt the patient may develop immediate or slowly progressive heart failure signs and symptoms. Repair of such defects is indicated and in the majority of cases RSVA can be treated using a variety of transcatheter devices, but surgery might be necessary if the patient has associated aortic regurgitation or VSD. TEE guidance of RSVA occlusion procedures begins with comprehensive assessment of the aortic root, aortic valve, and all cardiac chambers. It is imperative to identify which sinus is ruptured and which chamber it has ruptured into (Fig. 22.17). Multiplanar cross sectional measurement of RSVA size and specifically the largest diameter of the

c

Fig. 22.17  Ruptured right sinus of Valsalva aneurysm in a 26 year old with unrepaired supracristal ventricular septal defect who presents of 2 weeks of increasing weight gain, dyspnea and orthopnea. (a and b) 2D and color flow Doppler in the midesophageal long axis view at 125 degrees clearly demonstrating a high velocity shunt above the aortic valve. (c) Continuous wave spectral Doppler of the high-velocity shunt

710

a

J. Lin et al.

a

b

b

Fig. 22.19 (a) Midesophageal aortic valve long axis view with 2D and color Doppler demonstrating a perimembranous ventricular septal defect located 3  mm below right aortic valve leaflet. (b) Continuous wave Doppler demonstrates high velocity systolic flow and low velocity diastolic flow from left to right, consistent with a moderately restrictive perimembranous ventricular septal defect

Fig. 22.18  Transcatheter closure of the ruptured sinus of Valsalva aneurysm. (a) 3D live TEE, midesophageal long axis view demonstrating a wire crossing the defect from the aortic root and aortic valve (AoV) to the right ventricular outflow tract (RVOT). (b) Post-device closure with a muscular VSD occluder which is not impinging on the AoV, right coronary artery (RCA) ostium, or pulmonary valve (PV)

Ventricular Septal Defect Numerous VSD types may be encountered in adult patients. The majority are unrepaired or repaired congenital defects with residual flow or patch dehiscence. Rarely, patients will

present with post-traumatic or post-myocardial infarction VSD; these patients are often in florid heart failure or cardiogenic shock. Indications for VSD closure include presence of a significant shunt with left sided chamber dilation [56]. Transcatheter VSD closure is increasingly favored over surgical intervention in adult patients with congenital muscular VSDs, post-myocardial infarction or traumatic VSDs, post-­ surgical VSDs and a growing number of perimembranous defects. TEE assessment of the patient being considered for transcatheter VSD repair begins with comprehensive assessment of the type, location, size and flow characteristics of the VSD (Fig. 22.19). For perimembranous defects it is essential to assess the distance from the defect to the aortic valve in multiple views (Fig. 22.20). The presence or absence of tricuspid septal leaflet adhesions to the crest of the septum on the right ventricular side is important in identifying the presence or absence of a tricuspid septal leaflet aneurysm which could narrow the effective diameter of the VSD orifice and

22  Congenital Heart Disease in the Adult

711

a

b

Fig. 22.20 (a) Midesophageal five-chamber view at 0° demonstrating a perimembranous ventricular septal defect (VSD) that is ~6  mm in maximum diameter and located ~9 mm below the aortic valve (AoV). The 1.58  cm measurement is an attempt at predicting how an 8  mm muscular VSD occluder (which has a waist diameter of 8 mm and right and left sided disc diameters of 16 mm) would sit within this defect. (b) Followng deployment of an 8  mm muscular VSD occluder, there is complete cessation of VSD flow and minimal aortic regurgitation. Prior to device release, TEE was utilized to ensure the aortic valve was not grasped by the left sided disc

provide a stable “landing zone” for a closure device (Fig. 22.21). It is also imperative to assess for the presence of more than one “hole” and to appropriately inform the interventionalist of the wire or catheter course in this situation. 3D and multiplanar assessment of defect size and shape and defect distance from the aortic valve are  useful  to inform device selection. Procedural guidance is necessary following baseline defect assessment. The procedure typically consists of LV catheterization with a directional catheter following by wiring of the defect, which is facilitated by TEE guidance. The wire crosses the VSD into the right ventricle and the tip is snared from the femoral vein either within the pulmonary artery or the RA/SVC.  This “wire-rail” from the femoral artery to the femoral vein crosses through the aortic valve, the VSD and the tricuspid valve. Rarely this can result in injury to the aortic and tricuspid valves and therefore TEE

Fig. 22.21 (A) Inverted deep transgastric right ventricular outflow tract (RVOT) view at 90° demonstrating a perimembranous ventricular septal defect (VSD, small arrow) with left to right shunting into the RVOT. (B) Post device closure with a muscular VSD device demonstrating no residual shunting across the VSD but the device protrudes into the RVOT with resultant subpulmonary flow acceleration. PV pulmonary valve, RV right ventricle

assessment of valve competence is recommended during this stage of the procedure. Thereafter, a guide catheter or sheath is advanced over the wire-rail, typically via the femoral vein but occasionally via the femoral artery. If advancing via the femoral vein, the sheath is advanced into the aortic root and then the occlusion device is advanced to the sheath tip. Under TEE and fluoroscopic guidance, the sheath is withdrawn across the aortic valve and the LV disc is deployed, it is imperative for the sonographer to ensure that the disc is not fully deployed above the aortic valve since this can result in aortic valve injury as the device is pulled into the LV outflow tract. The unfurled left sided disc is then pulled taught against the VSD and then the waist and right sided discs are released under TEE guidance. Push and pull maneuvers are then performed to assess device stability. Prior to and following device release, the TEE should assess for presence of new or worsening aortic regurgitation, residual VSD flow, and new or worsening tricuspid valve regurgitation. Occasionally the

712

J. Lin et al.

closure device may result in subpulmonary stenosis which is best seen in the deep transgastric views (Fig.  22.21). Interventional closure of VSDs is also discussed in Chap. 21.

Left Atrial Appendage Occlusion Atrial fibrillation surpasses re-entrant atrial arrhythmia as the most common form of atrial arrhythmia in adult CHD patients older than 50 years of age [57]. Moreover, the prevalence of atrial fibrillation is expected to increase as the adult CHD population ages and the associated stroke risk is a major cause of morbidity and mortality. Stroke prevention with the use of a variety of anticoagulants is indicated in certain patients, but anticoagulation carries risks of bleeding complications. The vast majority of cardiac thrombi in those with atrial fibrillation occur with the LAA; therefore, multiple techniques have been developed to exclude the LAA in the hope that anticoagulation will not be necessary. Surgical LAA ligation or exclusion has been effectively performed for many decades and has proven efficacy. More recently, a variety of non-surgical technologies have been developed for appendage exclusion. TEE plays a central role in guiding and assessing the immediate procedural outcomes of such interventions. Several devices have been developed for transcatheter appendage occlusion: in the United States, the WatchmanTM device (Boston Scientific, Maple Grove, MN) and the Amplatzer Amulet (St Jude Medical, St Paul, MN) Fig. 22.22  Left atrial appendage (LAA) occlusion devices currently available in the United States, and their available sizes. Top figure: WatchmanTM device (Boston Scientific, Maple Grove, MN). Bottom figure: Amplatzer Amulet device (St Jude Medical, St Paul, MN). From Vainrib et al. [58], reprinted with permission from Elsevier

are FDA approved for prevention of stroke in non-valvular atrial fibrillation (Fig. 22.22) [58, 59]. Both require femoral venous access and a transseptal puncture, which requires echocardiographic guidance with either TEE or intracardiac echocardiography. The LAA is a complex structure with immense variability in shape, size, degree of trabeculation and number of lobes. It is often best visualized from a midesophageal left atrial appendage (ME LAA) view, transducer angle can be varied between 60–100°, and with some degree of TEE probe tip anteflexion given the cephalad location of the orifice. TEE should assess and address the following issues: [58, 59] 1. Rule out the presence of thrombus within the LAA and assess peak pulse wave Doppler velocity within the appendage; patients with velocities >55  cm/sec are unlikely to develop appendage thrombi. Biplane (X-plane) mode is especially useful in assessment for thrombus. Care should be taken to assess distal lobes and differentiate pectinate muscles from thrombi. 2. Assessment of the interatrial septum for transseptal puncture. If a patent foramen ovale is present it should be avoided as the site of catheter crossing because of the antero-superior orientation which does not allow for proper alignment of the delivery system within the LAA. 3. Assessment for the presence or absence of a pericardial effusion. Cardiac perforation is a known complication of LAA closure and transseptal puncture; therefore, baseline

WATCHMAN DEVICE SIZES Device Diameter (mm)

21

24

27

30

33

Max LAA Orifice Range (mm)

17-19

20-22

23-25

26-28

29-31

Compressed Diameter (mm)

16.8-19.3

19.2-22.1

21.6-24.8

24-27.6

26.4-30.4

AMULET DEVICE SIZES Diameter (mm)

16

Maximum Landing 11-13 Zone Width (mm)

18

20

22

25

28

31

34

13-15

15-17

17-19

19-22

22-25

25-28

28-31

Maximum LAA Depth (mm)

≥10

≥10

≥10

≥10

≥12

≥12

≥12

≥12

Lobe Length (mm)

7.5

7.5

7.5

7.5

10

10

10

10

Disc Diameter (mm)

22

24

26

28

32

35

38

41

22  Congenital Heart Disease in the Adult

713

Fig. 22.23  Biplane 2D TEE, midesophageal left atrial appendage view demonstrating a bilobed left atrial appendage. Measurements of orifice (landing zone) width and appendage length/depth are important for guiding occlusion device size

1 Distance = 1.82 cm 2 Distance = 2.96 cm 3 Distance = 2.00 cm 4 Distance = 2.57 cm

and ongoing assessment for a pericardial effusion throughout and immediately following the procedure is imperative. 4. Assessment of LV wall motion given the proximity of the LAA to the left circumflex artery and the possibility of coronary  artery compression by a device within the appendage. 5. Assessment of the LAA anatomy to determine suitability for the intended device. 2D measurements of the landing zone width, total appendage length and appendage depth perpendicular to the landing zone are necessary in multiple midesophageal planes (0°, 45°, 90°, and 135°) (Fig.  22.23). The appendage length determines how far the delivery catheter can be inserted into the appendage and whether the device can be placed at the appropriate landing zone within the mouth of the appendage. The appendage depth determines whether there is sufficient room for the length of the device. 3D assessment of the landing zone may be useful but 2D measurements are more reliable. Following device deployment, TEE is utilized to assess device position and residual flow. Push and pull maneuvers are often performed by the interventionalist prior to device release, the device and appendage should move in unison which suggests device stability. Minimal color flow around the device is often present. After device release, TEE should assess for any device displacement, color flow around the device, patency of the left upper pulmo-

nary vein ostium, new LV wall motion abnormality and presence of a pericardial effusion.

Summary TEE is a central imaging modality in the care of adults with CHD. Providers should be aware of the unique challenges of TEE in the adult patient, including indications and contraindications. TEE is most frequently used to diagnose or exclude small shunts, thrombi, or endocarditis, in evaluation of prosthetic valve dysfunction, and to guide surgical or transcatheter interventions.

Questions and Answers 1. Which of the following is an absolute contraindication for performing a TEE? (a) Grade I esophageal varices (b) Barrett’s esophagus (c) Prior Roux-en-Y gastric bypass (d) Active upper gastrointestinal bleeding (e) History of gastric ulcer Answer: d

714

Explanation: Active upper gastrointestinal bleeding is an absolute contraindication to performance of a TEE.  The other choices are relative contraindications. 2. Among the following patients, which one is most likely to prompt consideration for anesthesia support for a transesophageal echocardiogram? (a) Overweight 57 year old man without known obstructive sleep apnea (b) 64 year old woman with a history of social alcohol use (c) 23  year old woman with mild depression and anxiety (d) 45 year old woman with heroin dependence (e) 70 year old man with atrial fibrillation, hemodynamically stable. Answer: d Explanation: Given the history of heroin dependence, this patient might be more difficult to sedate due to tolerance to narcotics. Anesthetic care would be recommended for the TEE because of further available options that include higher doses of the commonly used drugs, alternate drugs, additional monitoring of cardiorespiratory status, and increased overall safety of the procedure. 3. Both TTE and TEE are recommended to evaluate for endocarditis in the adult patient with high risk features. Which of the following is not a high-risk feature? (a) Congenital heart disease (b) Prosthetic heart valve (c) Staphylococcus bacteremia (d) Streptococcus bacteremia Answer: d Explanation: Streptococcus  bacteremia per se is not a high-risk that automatically triggers a suspicion of endocarditis. There can be non-cardiac causes of this as well, and these should be ruled out before endocarditis is suspected. The other three choices are associated with a high risk of endocarditis, particularly congenital heart disease and prosthetic heart valves. 4. Which of the following imaging modalities is not recommended for the evaluation of complications related to transcatheter pulmonary valve replacement? (a) Transthoracic echocardiogram (b) Transesophageal echocardiogram (c) Intracardiac echocardiogram (d) Cardiac CT (e) Cardiac MRI Answer: e

J. Lin et al.

Explanation. The transcatheter pulmonary valve is housed in a stent that can cause a local signal void on MRI imaging. This will not be a problem with any of the echocardiographic modalities or CT imaging. 5. The configuration of the MitraClipTM delivery system requires that the transseptal puncture be done how many cm above the mitral valve annulus? (a) 4–4.5 cm (b) 4.5–5 cm (c) 3.5–4 cm (d) 3–3.5 cm (e) 5–5.5 cm Answer: a The transseptal puncture is best performed 4–4.5  cm above the mitral valve annulus to allow for proper positioning of the MitraClipTM device (see text for details). 6. Which of the following is not a recognized cause of a ruptured sinus of Valsalva aneurysm? (a) Connective tissue disease (b) Trauma (c) Aortic valve stenosis (d) Infection (e) Supracristal VSD Answer: c Explanation: Unlike all of the other choices, aortic valve stenosis is not generally associated with rupture of the sinus of Valsalva.

References 1. Hahn RT, Abraham T, Adams MS, Bruce CJ, Glas KE, Lang RM, et  al. Guidelines for performing a comprehensive transesophageal echocardiographic examination: recommendations from the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. J Am Soc Echocardiogr. 2013;26(9):921–64. 2. Marelli AJ, Child JS, Perloff JK.  Transesophageal echocardiography in congenital heart disease in the adult. Cardiol Clin. 1993;11(3):505–20. 3. Puchalski MD, Lui GK, Miller-Hance WC, Brook MM, Young LT, Bhat A, et  al. Guidelines for performing a comprehensive transesophageal echocardiographic: examination in children and all patients with congenital heart disease: recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019;32(2):173–215. 4. Pai SL, Aniskevich S 3rd, Feinglass NG, Ladlie BL, Crawford CC, Peiris P, et  al. Complications related to intraoperative transesophageal echocardiography in liver transplantation. Springerplus. 2015;4:480. 5. Oechslin EN, Harrison DA, Connelly MS, Webb GD, Siu SC. Mode of death in adults with congenital heart disease. Am J Cardiol. 2000;86(10):1111–6.

22  Congenital Heart Disease in the Adult 6. Verheugt CL, Uiterwaal CS, van der Velde ET, Meijboom FJ, Pieper PG, van Dijk AP, et al. Mortality in adult congenital heart disease. Eur Heart J. 2010;31(10):1220–9. 7. Zomer AC, Vaartjes I, Uiterwaal CS, van der Velde ET, van den Merkhof LF, Baur LH, et al. Circumstances of death in adult congenital heart disease. Int J Cardiol. 2012;154(2):168–72. 8. Zomer AC, Vaartjes I, van der Velde ET, de Jong HM, Konings TC, Wagenaar LJ, et  al. Heart failure admissions in adults with congenital heart disease; risk factors and prognosis. Int J Cardiol. 2013;168(3):2487–93. 9. Nagueh SF, Smiseth OA, Appleton CP, Byrd BF 3rd, Dokainish H, Edvardsen T, et  al. Recommendations for the evaluation of left ventricular diastolic function by echocardiography: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2016;17(12):1321–60. 10. Menon SC, Gray R, Tani LY.  Evaluation of ventricular filling pressures and ventricular function by Doppler echocardiography in patients with functional single ventricle: correlation with simultaneous cardiac catheterization. J Am Soc Echocardiogr. 2011;24(11):1220–5. 11. Cordina R, Ministeri M, Babu-Narayan SV, Ladouceur M, Celermajer DS, Gatzoulis MA, et al. Evaluation of the relationship between ventricular end-diastolic pressure and echocardiographic measures of diastolic function in adults with a Fontan circulation. Int J Cardiol. 2018;259:71–5. 12. Finn JP, Nguyen KL, Han F, Zhou Z, Salusky I, Ayad I, et  al. Cardiovascular MRI with ferumoxytol. Clin Radiol. 2016;71(8):796–806. 13. Lai LM, Cheng JY, Alley MT, Zhang T, Lustig M, Vasanawala SS. Feasibility of ferumoxytol-enhanced neonatal and young infant cardiac MRI without general anesthesia. J Magn Reson Imaging. 2017;45(5):1407–18. 14. Muthalaly RG, Nerlekar N, Ge Y, Kwong RY, Nasis A.  MRI in patients with cardiac implantable electronic devices. Radiology. 2018;289(2):281–92. 15. Abdelghani M, Nassif M, Blom NA, Van Mourik MS, Straver B, Koolbergen DR, et  al. Infective endocarditis after melody valve implantation in the pulmonary position: a systematic review. J Am Heart Assoc. 2018;7(13). 16. Aad G, Abbott B, Abdallah J, Abdinov O, Aben R, Abolins M, et  al. ATLAS Run 1 searches for direct pair production of third-­ generation squarks at the Large Hadron Collider. Eur Phys J C Particles Fields. 2015;75(10):510. 17. Idorn L, Jensen AS, Juul K, Reimers JI, Johansson PI, Sorensen KE, et  al. Thromboembolic complications in Fontan patients: population-­ based prevalence and exploration of the etiology. Pediatr Cardiol. 2013;34(2):262–72. 18. Marrone C, Galasso G, Piccolo R, de Leva F, Paladini R, Piscione F, et al. Antiplatelet versus anticoagulation therapy after extracardiac conduit Fontan: a systematic review and meta-analysis. Pediatr Cardiol. 2011;32(1):32–9. 19. Tomkiewicz-Pajak L, Hoffman P, Trojnarska O, Lipczynska M, Podolec P, Undas A. Abnormalities in blood coagulation, fibrinolysis, and platelet activation in adult patients after the Fontan procedure. J Thorac Cardiovasc Surg. 2014;147(4):1284–90. 20. Broberg CS, Aboulhosn J, Mongeon FP, Kay J, Valente AM, Khairy P, et  al. Prevalence of left ventricular systolic dysfunction in adults with repaired tetralogy of fallot. Am J Cardiol. 2011;107(8):1215–20. 21. Varma C, Warr MR, Hendler AL, Paul NS, Webb GD, Therrien J.  Prevalence of “silent” pulmonary emboli in adults after the Fontan operation. J Am Coll Cardiol. 2003;41(12):2252–8. 22. Haeffele C, Lui GK.  Dextro-transposition of the great arter ies: long-term sequelae of atrial and arterial switch. Cardiol Clin 2015;33(4):543–58, viii.

715 23. Williams RG, Pearson GD, Barst RJ, Child JS, del Nido P, Gersony WM, et al. Report of the National Heart, Lung, and Blood Institute Working Group on research in adult congenital heart disease. J Am Coll Cardiol. 2006;47(4):701–7. 24. Kaulitz R, Stumper OF, Geuskens R, Sreeram N, Elzenga NJ, Chan CK, et  al. Comparative values of the precordial and transesophageal approaches in the echocardiographic evaluation of atrial baffle function after an atrial correction procedure. J Am Coll Cardiol. 1990;16(3):686–94. 25. Antonielli E, Pizzuti A, Palinkas A, Tanga M, Gruber N, Michelassi C, et al. Clinical value of left atrial appendage flow for prediction of long-term sinus rhythm maintenance in patients with nonvalvular atrial fibrillation. J Am Coll Cardiol. 2002;39(9):1443–9. 26. Otto CM.  Textbook of clinical echocardiography, 6th ed. Philadelphia, PA: Elsevier/Saunders; 2019. xiv, 564 pages p. 27. Moore B, Cao J, Kotchetkova I, Celermajer DS. Incidence, predictors and outcomes of infective endocarditis in a contemporary adult congenital heart disease population. Int J Cardiol. 2017;249:161–5. 28. Tutarel O, Alonso-Gonzalez R, Montanaro C, Schiff R, Uribarri A, Kempny A, et  al. Infective endocarditis in adults with congenital heart disease remains a lethal disease. Heart. 2018;104(2):161–5. 29. Granger CB, Alexander JH, McMurray JJ, Lopes RD, Hylek EM, Hanna M, et  al. Apixaban versus warfarin in patients with atrial fibrillation. N Engl J Med. 2011;365(11):981–92. 30. Mylotte D, Rushani D, Therrien J, Guo L, Liu A, Guo K, et  al. Incidence, predictors, and mortality of infective endocarditis in adults with congenital heart disease without prosthetic valves. Am J Cardiol. 2017;120(12):2278–83. 31. Baddour LM, Epstein AE, Erickson CC, Knight BP, Levison ME, Lockhart PB, et al. Update on cardiovascular implantable electronic device infections and their management: a scientific statement from the American Heart Association. Circulation. 2010;121(3): 458–77. 32. Lerakis S, Hayek SS, Douglas PS.  Paravalvular aortic leak after transcatheter aortic valve replacement: current knowledge. Circulation. 2013;127(3):397–407. 33. Ionescu A, Fraser AG, Butchart EG.  Prevalence and clinical significance of incidental paraprosthetic valvar regurgitation: a prospective study using transoesophageal echocardiography. Heart. 2003;89(11):1316–21. 34. Cho YH, Jun TG, Yang JH, Park PW, Huh J, Kang IS, et al. Surgical strategy in patients with atrial septal defect and severe pulmonary hypertension. Heart Surg Forum. 2012;15(2):E111–5. 35. Kuijpers JM, Koolbergen DR, Groenink M, Peels KCH, Reichert CLA, Post MC, et  al. Incidence, risk factors, and predictors of infective endocarditis in adult congenital heart disease: focus on the use of prosthetic material. Eur Heart J. 2017;38(26):2048–56. 36. Uebing A, Rigby ML.  The problem of infective endocardi tis after transcatheter pulmonary valve implantation. Heart. 2015;101(10):749–51. 37. Van Dijck I, Budts W, Cools B, Eyskens B, Boshoff DE, Heying R, et  al. Infective endocarditis of a transcatheter pulmonary valve in comparison with surgical implants. Heart. 2015;101(10):788–93. 38. Chaudhry-Waterman N, Bergersen L, Buber J.  Bacterial endo carditis manifesting as outflow tract obstruction in two patients implanted with percutaneous prosthetic pulmonary valves. Can J Cardiol. 2015;31(9):1204 e1–3. 39. Cheung G, Vejlstrup N, Ihlemann N, Arnous S, Franzen O, Bundgaard H, et  al. Infective endocarditis following percutaneous pulmonary valve replacement: diagnostic challenges and application of intra-cardiac echocardiography. Int J Cardiol. 2013;169(6):425–9. 40. Georgievskaya Z, Nowalk AJ, Randhawa P, Picarsic J. Bartonella henselae endocarditis and glomerulonephritis with dominant C3 deposition in a 21-year-old male with a Melody transcatheter pul-

716 monary valve: case report and review of the literature. Pediatr Dev Pathol. 2014;17(4):312–20. 41. Miranda WR, Connolly HM, Bonnichsen CR, DeSimone DC, Dearani JA, Maleszewski JJ, et  al. Prosthetic pulmonary valve and pulmonary conduit endocarditis: clinical, microbiological and echocardiographic features in adults. Eur Heart J Cardiovasc Imaging. 2016;17(8):936–43. 42. Yedidya I, Stein GY, Vaturi M, Blieden L, Bernstine H, Pitlik SD, et al. Positron emission tomography/computed tomography for the diagnosis of endocarditis in patients with pulmonic stented valve/ pulmonic stent. Ann Thorac Surg. 2011;91(1):287–9. 43. Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP 3rd, Fleisher LA, et  al. 2017 AHA/ACC focused update of the 2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/ American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2017;70(2):252–89. 44. Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP 3rd, Guyton RA, et al. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;63(22):2438–88. 45. Stone GW, Lindenfeld J, Abraham WT, Kar S, Lim DS, Mishell JM, et  al. Transcatheter mitral-valve repair in patients with heart failure. N Engl J Med. 2018;379(24):2307–18. 46. Lim DS, Reynolds MR, Feldman T, Kar S, Herrmann HC, Wang A, et  al. Improved functional status and quality of life in prohibitive surgical risk patients with degenerative mitral regurgitation after transcatheter mitral valve repair. J Am Coll Cardiol. 2014;64(2):182–92. 47. Glower DD, Kar S, Trento A, Lim DS, Bajwa T, Quesada R, et al. Percutaneous mitral valve repair for mitral regurgitation in high-­ risk patients: results of the EVEREST II study. J Am Coll Cardiol. 2014;64(2):172–81. 48. Fender EA, Zack CJ, Nishimura RA.  Isolated tricuspid regur gitation: outcomes and therapeutic interventions. Heart. 2018;104(10):798–806. 49. Lancellotti P, Price S, Edvardsen T, Cosyns B, Neskovic AN, Dulgheru R, et  al. The use of echocardiography in acute cardiovascular care: recommendations of the European Association of Cardiovascular Imaging and the Acute Cardiovascular Care Association. Eur Heart J Cardiovasc Imaging. 2015;16(2):119–46. 50. Nath J, Foster E, Heidenreich PA. Impact of tricuspid regurgitation on long-term survival. J Am Coll Cardiol. 2004;43(3):405–9.

J. Lin et al. 51. Kilic A, Saha-Chaudhuri P, Rankin JS, Conte JV. Trends and outcomes of tricuspid valve surgery in North America: an analysis of more than 50,000 patients from the Society of Thoracic Surgeons database. Ann Thorac Surg 2013;96(5):1546–52; discussion 52. 52. Jang JY, Heo R, Lee S, Kim JB, Kim DH, Yun SC, et  al. Comparison of results of tricuspid valve repair versus replacement for severe functional tricuspid regurgitation. Am J Cardiol. 2017;119(6):905–10. 53. McElhinney DB, Cabalka AK, Aboulhosn JA, Eicken A, Boudjemline Y, Schubert S, et  al. Transcatheter tricuspid valve-­ in-­valve implantation for the treatment of dysfunctional surgical bioprosthetic valves: an international multicenter registry study. Circulation. 2016; 54. Aboulhosn J, Cabalka AK, Levi DS, Himbert D, Testa L, Latib A, et al. Transcatheter valve-in-ring implantation for the treatment of residual or recurrent tricuspid valve dysfunction after prior surgical repair. JACC Cardiovasc Interv. 2017;10(1):53–63. 55. Braun D, Nabauer M, Orban M, Orban M, Gross L, Englmaier A, et  al. Transcatheter treatment of severe tricuspid regurgitation using the edge-to-edge repair technique. EuroIntervention. 2017;12(15):e1837–e44. 56. Stout KK, Daniels CJ, Aboulhosn JA, Bozkurt B, Broberg CS, Colman JM, et  al. 2018 AHA/ACC guideline for the management of adults with congenital heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2018. 57. Labombarda F, Hamilton R, Shohoudi A, Aboulhosn J, Broberg CS, Chaix MA, et al. Increasing prevalence of atrial fibrillation and permanent atrial arrhythmias in congenital heart disease. J Am Coll Cardiol. 2017;70(7):857–65. 58. Vainrib AF, Harb SC, Jaber W, Benenstein RJ, Aizer A, Chinitz LA, et  al. Left atrial appendage occlusion/exclusion: procedural image guidance with transesophageal echocardiography. J Am Soc Echocardiogr. 2018;31(4):454–74. 59. Deegan R, Ellis CR, Bennett JM.  Left atrial appendage occlusion devices. Semin Cardiothorac Vasc Anesth. 2018:1089253218789159. 60. Zoghbi WA, Adams D, Bonow RO, Enriquez-Sarano M, Foster E, Grayburn PA, et al. Recommendations for noninvasive evaluation of native valvular regurgitation a report from the American Society of Echocardiography Developed in Collaboration with the Society for Cardiovascular Magnetic Resonance. J Am Soc Echocardiogr. 2017;30(4):303–71.

Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

23

Pierre C. Wong and Gerald R. Marx

Abbreviations 2D Two-dimensional 3D CFD 3D Color flow Doppler 3D TEE Three-dimensional transesophageal echocardiography 3D Three-dimensional AV Atrioventricular CHD Congenital heart disease CMR Cardiac magnetic resonance imaging ECG Electrocardiogram LV Left ventricle MPR Multiplanar reformatted RV Right ventricle TEE Transesophageal echocardiography

Key Learning Objectives • Understand the technology of three-dimensional transesophageal echocardiography (3D TEE), including the history of its development • Be acquainted with the different methods of 3D TEE acquisition and display

Electronic Supplementary Material The online version of this chapter (https://doi.org/10.1007/978-­3-­030-­57193-­1_23) contains supplementary material, which is available to authorized users. P. C. Wong (*) Division of Cardiology, Heart Institute, Children’s Hospital Los Angeles, Los Angeles, CA, USA Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA e-mail: [email protected] G. R. Marx Department of Cardiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA

• Understand the unique aspects of 3D TEE dataset evaluation • Recognize the advantages of real-time 3D TEE • Be familiar with the important applications of 3D TEE for congenital heart disease • Know some of the potential limitations and pitfalls of TEE

Introduction With the advent of matrix array transducers and sophisticated computer analysis, three-dimensional (3D) echocardiography is now widely applied in the diagnostic imaging domain for congenital heart disease (CHD). Over the past two decades, there has been a significant increase in the number and variety of 3D transesophageal echocardiography (3D TEE) applications: for diagnostic evaluation, for monitoring and guiding interventional cardiology procedures, and for the preoperative and postoperative assessment of cardiac surgery. In regard to operative management of complex CHD, congenital heart surgeons will sometimes request 3D imaging to provide additional information about cardiac anatomy and spatial relationships. This especially applies for repair of valve dysfunction, in which the anatomic substrate can be difficult to discern with standard two-dimensional (2D) imaging. This chapter serves as an introduction to 3D TEE—the technology, basic principles of image acquisition, reconstruction, and display, and clinical applications, particularly for CHD evaluation. Emphasis will be focused on specific clinical examples in which intraoperative 3D TEE imaging can provide additional important information to guide either catheter-based or surgical planning. The reader is encouraged to read both this chapter and Chap. 24 (Clinical Applications of 3D TEE in CHD) together, as each chapter complements the other. As will become apparent from these two chapters, 3D TEE clearly provides significant additional value for a number of different cardiac defects, and the applications continue to increase. Expertise in the performance of 3D TEE  has now become a well-accepted and often

© Springer Nature Switzerland AG 2021 P. C. Wong, W. C. Miller-Hance (eds.), Transesophageal Echocardiography for Pediatric and Congenital Heart Disease, https://doi.org/10.1007/978-3-030-57193-1_23

717

718

required diagnostic capability for many pediatric and adult centers that provide care to patients with both acquired and congenital heart disease. A note regarding terminology. In the medical literature, both “3D” and “4D” (four-dimensional) are used when referring to 3D echocardiography. The use of the term 4D is meant to describe the 3D depiction of a moving object (such as the heart), in which a 3D rendering is displayed using real-­ time motion—thus time represents the fourth dimension. In current ultrasound parlance, the two terms are used synonymously and interchangeably. For simplicity, in this chapter “3D” will used to represent both terms.

History and Development In the initial development of 3D echocardiography, the acquisition phase was performed by the sequential acquisition of transesophageal 2D echocardiographic images [1– 6]. The probe was moved in a linear or rotational format, and was advanced to subsequent imaging planes, based on electrocardiographic (ECG) and respiratory gating. Excellent 3D gray scale and color flow studies were obtained. However, this technology was time consuming and cumbersome. Depending on the heart rate, the acquisition would last from at least 3–5 min. Significant arrhythmias would interfere with the acquisition. Moreover, to maintain spatial integrity, the heart had to be stationary from a positional standpoint. Furthermore, the formatting of the 2D images into a 3D construct consumed additional valuable time. Although certain dedicated and cooperative surgeons would participate, this form of 3D imaging was not widely applied in the operative suite. With advancements in probe design, and sophisticated, efficient and fast computers, nearly simultaneous imaging of volumetric echocardiographic 3D data sets became available. These advanced matrix array transducers were relatively smaller. Hence, epicardial 3D echocardiography evolved as these matrix array probes could be held and manipulated comfortably on the heart by the surgeon [7]. The surgeon could investigate the anatomy in the “live” 3D display. Similar to 2D imaging, immediate anatomic “feedback” was available, but in a 3D spatial orientation. Even full volume acquisitions could be obtained, and the specific anatomy segmented and displayed to the surgeon in minutes. Although excellent 3D images could be shown in the operating room, available for surgical planning, certain disadvantages with epicardial 3D echocardiography were apparent. First, imaging in the near field was suboptimal due to the very short focal distance. Secondly, in the very vigorously beating heart, stable contact of the transducer with the cardiac structures was difficult to maintain. Third, this type of image acquisition occupied and usurped the time and con-

P. C. Wong and G. R. Marx

centration of the operating surgeon [8]. These important limitations, coupled with the development of a real-time 3D TEE probe in 2007 (X7-2t, Philips Medical Systems, Andover, Massachusetts) [9], have led to the use of 3D TEE as the preferred technique in the operative setting (for patients of adequate size). Despite this important achievement, epicardial 3D echocardiography can still be used: (1) for the young and small pediatric patients in whom the 3D TEE probe is too large; (2) for those pediatric or adult patients with specific contraindications to TEE. 3D TEE has readily become accepted for adult patients undergoing cardiothoracic surgery or catheter-based interventions [9–15]. This technological advancement has also been applied to adult patients with CHD (Chap. 22). However, with careful patient selection, and collaboration between the cardiologist and anesthesiologist, 3D TEE can be used safely in selected children and adolescents [16–23]. As opposed to epicardial imaging, 3D TEE can be undertaken without interfering with the surgical field. Additionally, this imaging can provide a more comprehensive and larger field of view. This latter advantage probably arises from the offset of the transducer from the heart. Still, 3D TEE imaging can be challenging in the near field, especially for visualization of the atria and pulmonary veins.

General Concepts 3D TEE Probe Technology The technology of the current real-time 3D TEE probes was discussed in Chaps. 1 and 2, but will be detailed again in this chapter. The following discussion applies specifically to the Philips X7-2t and X8-2t 3D TEE probes; however, many of the same principles apply to other 3D systems utilizing matrix array technology. Physically, the 3D TEE probe looks very similar to a standard 2D transesophageal echocardiography (TEE) probe. The same standard TEE handle controls are available— antero-posterior and left/right flexion, as well as a transducer angle control which can rotate the 2D tomographic plane from 0° to 180° (Fig. 23.1a). This control is provided because the 3D TEE probe also provides the capability for excellent 2D multiplane imaging. The 3D TEE probe tip is shaped similar to its 2D counterpart, although it is slightly larger in size (Fig. 23.1b). This larger tip is designed to accommodate the highly advanced, miniaturized technology that makes possible real-time 3D TEE imaging. The typical 2D multiplane TEE probe consists of a phased array transducer containing 64–128 piezoelectric crystals (elements) placed side by side in a rectangular row (Fig. 23.2a). As described in Chap. 1, sequential activation of these crystals produces a beam that is steered back and forth to obtain a flat, pie-shaped scanning plane. This creates the

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

Fig. 23.1  The Philips X7-2t 3D TEE probe. (a) Shows the handle of the probe; it has identical controls as a standard 2D TEE probe. When used for 2D TEE imaging, the transducer angle control (shown) rotates

a

b

Fig. 23.2  Diagram of adult transesophageal (TEE) 2D and 3D probes. (a) Illustrates a standard multiplane 2D TEE probe, which uses a linear phased array containing 64–128 piezoelectric elements. Using a control on the TEE probe handle, the array is physically rotated either electronically or mechanically to obtain a transducer angle between 0° and 180°. (b) Illustrates a 3D TEE matrix array probe with over 2500 elements arranged in a square grid. Scan lines are generated both azimuthally (laterally) and elevationally, thus a pyramidal volume can be obtained, enabling the acquisition of a 3D volume dataset

standard tomographic 2D images customarily seen with the TEE systems currently in use. In a 2D multiplane TEE probe, the rectangular array of elements is physically rotated (electronically or mechanically) in a semicircular manner between 0–180° (Fig. 23.2a), thereby obtaining the various 2D TEE

719

b

the imaging plane between 0° and 180°. Panel (b) is a photo of the Philips adult transesophageal (TEE) 2D and 3D probes side by side. Note that the 3D TEE probe is slightly larger than its 2D counterpart

tomographic images commonly seen in this and other sources. In contrast, the 3D TEE probe contains a matrix array of 2500+ piezoelectric crystals arranged in a square 10 × 10 mm grid (Figs. 23.1b, 23.2b). The individual elements are electrically independent, allowing for generation of scan lines than can vary both azimuthally (laterally) and elevationally (Fig. 23.2b). Thus, a pyramidal 3D “wedge” of acoustic raw data information can be obtained and subsequently processed into Cartesian coordinates using a 3D scan converter; each discrete point in the scan converter is known as a voxel (“volumetric pixel”), which is cubic in shape and carries a discrete coordinate in 3D space as well as a value for echo intensity [24–26]. This is analogous to the pixels (picture elements) used to form a 2D image. Voxels therefore constitute the basic components used to construct a 3D dataset [5]. Since voxels represent discrete data points, interpolation is used to fill in the gaps between the voxels, using adjacent data of similar characteristics [25]. The resultant 3D image depends upon the size of the voxels and voxel density. Analogous to 2D imaging, smaller voxels and increased number of scan lines lead to a higher voxel count and less data interpolation, which in turn enhances the spatial resolution of the 3D image. However, the tradeoff is temporal resolution. There is a large volume of data (several thousand scan lines) that needs to be collected and processed for a single 3D volume dataset, and if the processing of this dataset were performed in a manner akin to standard 2D echocardiography, the time required would result in unacceptably low volume rates. To address this, parallel beamforming (parallel processing) is utilized. In this technique, the system transmits one wide beam and receives multiple narrow beams in parallel [27], which enables much faster 3D image processing, thereby permitting the motion of the 3D images to be displayed at clinically acceptable volume rates. Nonetheless, as a result of the greater data processing requirements, the current volume rates for live 3D imaging

720

P. C. Wong and G. R. Marx

are still much less than those achievable by conventional 2D imaging. Also, parallel beamforming comes at a cost: there is an accompanying increase in the amount of beamforming electronics, as well as size, cost, and power consumption of the system [27]. The process of displaying a 3D data set on a 2D computer screen is known as rendering, and can be performed by one of several different methods. The first method, known as wireframe rendering, shows the surface of a structure as a series of lines connected together to form a mesh of interconnected polygons that altogether form a cage-like, wireframe 3D model of the surface of the heart (Fig. 23.3a). This method was originally designed for computer-assisted design and manufacturing (CAD/CAM), and is well suited for ventricular wall motion although it cannot display more complex internal structures such as valvular structures [5]. The second method is known as surface rendering. Similar to wireframe rendering, surface rendering displays the details of a structure’s surface but defines more points to present a solid appearance (Fig. 23.3b). Both wireframe and surface rendering utilize manual tracing or semiautomatic border detection algorithms (identification of blood-tissue boundary) to trace the endocardium in cross-sectional images derived from segmentation of the 3D dataset; these are then used to generate a 3D model of the surface and shape of the structure in question (usually a ventricle). This 3D/4D volume “cast” can then be used for quantification of ventricular volume, synchrony and Fig. 23.3  Examples of different modes in which 3D echocardiographic data sets can be visualized and rendered. The techniques used to display the images can be divided into four broad categories: wireframe (a), surface rendering (b), volume rendering (c), and 2D tomographic slicing (d). These displays were obtained from transthoracic 3D imaging, but the principles of image rendering and display apply equally with 3D transesophageal imaging. Reprinted from Lang et al. [28], with permission from Elsevier

a

d

function [24]. The third method of rendering, known as volume rendering, is the method used most frequently in realtime 3D imaging, particularly for the evaluation of structural abnormalities such as those seen in CHD. This method preserves all 3D information within the dataset, and rendering is performed to provide a realistic 3D depiction of all the anatomic details within the heart. This is achieved by using different algorithms to cast a light beam through the voxels, and weighting the voxels to obtain a voxel gradient intensity. A variety of digital shading and lighting techniques (perspective, light casting, and depth color-coding) are used to achieve the perception of 3D depth and texture on a 2D computer screen (Fig.  23.3c) [29]. Using tools available both on the echocardiography machine as well as offline, these volume datasets can be sectioned (cropped) from any number of different viewpoints, and rotated to reveal the spatial relationships of atrioventricular/semilunar valves and complex intracardiac anatomy. Also, the source of the light beam (and therefore shading/lighting) is projected to maintain a sense of depth and three dimensionality, even while the 3D volume dataset is rotated and sectioned. Volume rendered datasets can be displayed in several principal modes: 1. Real-time (Live) 3D. This mode, activated by a single button, provides true live, real-time 3D imaging of the beating heart. However only a portion of the heart is contained in the 3D dataset. It is obtained in such a manner

b

c

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

that the “front” portion of the dataset (nearest the observer) automatically displays a tomographic slice identical to the 2D image that was shown prior to 3D activation, but with rendered volumetric imaging behind the slice to provide additional information and a 3D perspective (Figs.  23.4a and 23.5, Video 23.1). This 3D mode yields a narrow pyramidal volume with dimensions 30°  ×  60°. Since the “live” format is truly realtime, no gating to respiration or ECG is necessary. However, because the structure(s) in question has been “sectioned” to mimic the 2D tomographic image for visualization and orientation, the resultant 3D dataset will not include the entire structure. This mode has a temporal resolution (volume rate) that is generally sufficient for monitoring real-time motion and guiding interventional procedures (often 20–30 Hz). In some systems, the volume rate can be increased by reducing line density which results in better temporal resolution at the expense of spatial resolution. 2. 3D Zoom. This mode is also a “live” mode. A specific region of interest (e.g. the mitral valve or atrial septum) is identified, and a smaller volume dataset positioned to provide a focused, magnified, complete 3D visualization of the region as a smaller and narrower pyramid (Figs. 23.4b and 23.6, Video 23.2). The pyramid angles can vary from 20° × 20° to 90° × 90°, with a dimension of 30° × 30° commonly used. By reducing the volume size and focusing solely upon the structure of interest, the entire structure can be contained in the dataset, and the lateral resolution can be improved by increasing the number of scan lines, while still maintaining acceptable volume rates. The live images can still be cropped and rotated in multiple orientations. Linear and area measurea

Live 3D

b

3D Zoom

Fig. 23.4  The different modes of volume rendering. Panel (a) is an illustration showing a Live 3D volume, acquired in one beat and without the need for gating. (b) Shows 3D Zoom mode: only data within a small region of interest are acquired, the data are collected in one beat,

721

ments can also be performed on the images. However, progressive increasing of the magnification can produce deterioration in temporal resolution (sometimes down to 5–10  Hz) [29]. Some manufacturers have developed methods for increasing volume rates (such as high volume rate or HVR mode by Philips). 3. ECG-gated multibeat acquisition. This is an acquisition mode in which a large 3D volume dataset (also known as “full volume”) is assembled from several adjacent wedge-­ shaped 3D subvolumes that are collected rapidly and sequentially using ECG-gating. A total of 2–6 subvolumes are obtained and then digitally reassembled or “stitched” into a large pyramidal digital dataset, which is then available for viewing and manipulation (Figs. 23.4c and 23.7, Video 23.3). Strictly speaking, a full volume dataset is not real-time since it represents an ECG-gated assemblage of subvolumes collected sequentially over a matter of seconds, but for all practical purposes it is nearly so because of the very short acquisition and display time. This mode provides excellent spatial and temporal resolution (20–50 Hz, depending upon number of beats captured), and because of the wide dimensions of the volume dataset (90° × 90°), entire structures can be completely captured within the dataset. However due to the gating, full volume datasets can be subject to “stitch” artifact (imperfect alignment of subvolumes) if there is significant respiratory motion or any ECG abnormality. Of note, to circumvent the “stitch” artifact, single beat large volume acquisition is available. However, depending upon the size of the volume, this method can significantly reduce volume rates (temporal resolution), thereby limiting its effectiveness in infants and small children with higher heart rates. c

Full Volume

and no gating is required. (c) Shows a Full Volume dataset in which four subvolumes that have been sequentially acquired and “stitched” together to form one large volume. Creation of a Full Volume requires gating to the electrocardiogram

722

P. C. Wong and G. R. Marx

a

b

c

Fig. 23.5  Example of three-dimensional “Live 3D” format in a patient with repaired tetralogy of Fallot and an abnormal aortic valve. A standard midesophageal aortic valve long axis view (a) was used to position and orient the probe. (b) Shows the “Live 3D” mode volume dataset. Note that the front portion of the dataset displays the tomographic

image similar to the standard 2D image, which helps to orient the echocardiographer. (c) Shows the dataset rotated to show the thickness of the volume. Note that volumetric data is obtained behind the image, but the entire aortic valve is not contained in the dataset. Ao aorta, LA left atrium, LVOT left ventricular outflow tract, RV right ventricle

Fig. 23.6  3D Zoom the allows a closeup, real-time view of an atrial septal defect using on-cart cropping tools. In this case, the diameters of the defect can also be measured on the echocardiography machine

4. 2D Simultaneous Multiplane Mode. One of the unique features of the matrix array is that several different 2D tomographic planes can be displayed simultaneously from the same volume dataset, a feature variously known as biplane, triplane, or multiplane imaging (Fig. 23.3d). These can be displayed as equidistant parallel slices (as shown in Fig. 23.3d), three orthogonal planes together, or slices rotated around a common axis. For example, with the Philips 3D TEE system, two different live 2D images can be displayed next to each other using the xPlane mode, as shown in Fig. 23.8, Video 23.4. For this modality, the extra plane can be electronically varied. In this example, midesophageal four-chamber and long axis views are shown simultaneously. Multiplane imaging from a 3D volume dataset has been shown to be useful when evaluating CHD [30]. This feature is useful for any

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

structure in which real-time, simultaneous visualization of multiple planes can provide important information such as atrial septal defect (ASD) or ventricular septal defect (VSD) closures, cannula placement, visualization of outflow tract lesions, etc.

Fig. 23.7 Example of the three-dimensional full volume dataset acquired in the patient from Fig. 23.5. Four subvolumes were collected and rapidly stitched together to form a pyramidal dataset. Now a significant portion of the heart, including the whole aortic valve, is contained in this dataset. The volume has been rotated from its initial acquisition display, and lines have been drawn to illustrate the manner in which the subvolumes are collected and stitched together Fig. 23.8  xPlane mode from the Philips X7-2t 3D TEE probe. Two different 2D planes are shown simultaneously in this patient with mild subaortic stenosis. On the left is a midesophageal four chamber view, on the right a midesophageal long axis view. The circle on the display indicates the relationship of the two planes

723

5. 3D Color Doppler. 3D color flow Doppler can be added to any of the above modes, with the 3D color Doppler information superimposed upon the 3D image ­information. However, depending upon the size of the dataset, the addition of the color flow information can significantly reduce temporal resolution, sometimes 20–25 kg, although successful probe insertion down to 15.5  kg has been reported [17]. Nonetheless, even in older patients with CHD, 3D TEE has found utility in a number of different clinical settings. For example, 3D TEE imaging, which already has found widespread applicability for adult cardiac interventional procedures in the catheterization laboratory, has increasing utility for older children and young adults in the same setting. This applies not only for

3D TEE for CHD Evaluation  onsiderations for 3D TEE in the Evaluation C of CHD One of the most frequently asked questions is: which patients should get a 3D echocardiographic study, in addition to standard 2D imaging? This is especially germane to 3D TEE imaging, which requires some additional effort compared to 2D TEE imaging. At our centers, the surgeon most often

728

visualization of the aforementioned atrial and ventricular septal defects for device closure, but also for other types of cardiac interventions and also detection of thrombus formation for patients considered for electrical cardioversion. In the ambulatory setting, 3D TEE can be used for the adolescent or adult patient in whom surgery is contemplated, when transthoracic imaging is suboptimal and cardiac MRI imaging either not feasible, suboptimal, or contraindicated. Thus, a patient may undergo a 3D TEE study to determine the feasibility of either catheterization or surgical based intervention. 3D TEE can also be used in the operative setting. Often it has better imaging resolution than transthoracic 3D echocardiography, hence the preoperative study serves a vital role by providing important imaging planes for the surgeon to aid in the planning of the operation. Postoperatively, this imaging can be applied during separation from bypass to evaluate the success of the surgery.  The intraoperative environment presents challenges for 3D TEE imaging: the changes in cardiac position (due to surgical manipulations) and variations in cardiac rhythm, as well as the need for imaging information as quickly as possible, often preclude the ability to perform extensive and time-consuming image acquisition, cropping, and image manipulation, particularly with full volume datasets. In this setting, live 3D TEE imaging and 3D zoom are generally preferable; time permitting, rapid cropping of full volume datasets (imaging and color flow Doppler) can also be performed if the dataset quality is acceptable. 

 linical Application for 3D TEE C in the Evaluation of CHD Much of the published literature on the subject of 3D echocardiography for CHD evaluation is based upon extensive experience with real time transthoracic (and even fetal) 3D echocardiography [19, 46–51]. However, the matrix array technologies for real-time transthoracic and transesophageal 3D echocardiography are very similar, and therefore one can expect considerable overlap between the two modalities in terms of clinical applications. The major advantage of 3D TEE is the enhanced resolution of the 3D images (compared to transthoracic 3D echocardiography), particularly in larger patients with poor transthoracic windows. Furthermore, TEE is typically performed in more controlled clinical settings (often intubated patients undergoing general anesthesia), thus permitting better acquisition of large ECG-gated multibeat (full volume) datasets. There is a growing body of literature documenting the expanding clinical applications of 3D TEE for CHD evaluation [17, 19, 22, 23, 52–54]. Table 23.1 lists some of the more commonly accepted indications for 3D TEE in patients with CHD [23].

P. C. Wong and G. R. Marx Table 23.1  Clinical applications for which 3D TEE has been used successfully 3D TEE in patients with CHD is recommended for the following:  •  ASD device closure guidance  •  VSD device closure guidance  •  Visualization of catheters, delivery systems and devices  •  Measurements of defects visualized in en face views  •  Analysis of the anatomy and function of atrioventricular valves  •  Visualization of the aortic valve and left ventricular outflow tract 3D TEE in patients with CHD has been used successfully for the following:  •  Fontan fenestration device closure  •  Ruptured sinus of Valsalva aneurysm device closure  •  Coronary artery fistula device closure  •  Prosthetic valve paravalvar leak device closure  •  Atrial switch baffle leak device closure  •  Atrial septum transseptal catheterization during various procedures  •  Biventricular pacemaker synchrony assessment and lead placement guidance Abbreviations: ASD atrial septal defect, VSD ventricular septal defect From: Puchalski et al. [23], with permission from Elsevier

Up to the present time, most of the applications focus upon structural/morphologic evaluation of CHD, primarily in the intraoperative and interventional catheterization settings (as befits the most common venues for TEE in this setting). In this section, some of the more common clinical applications will be discussed. Not all applications of 3D TEE can be presented; however, examples of specific CHD abnormalities most commonly evaluated will be discussed below.

Evaluation of Atrioventricular Valves Evaluation of the AV valves represents one of the most well-­ established indications for 3D echocardiography in adults and children. A number of studies have documented the utility of both transthoracic and transesophageal 3D echocardiography, especially for mitral valve disease in adults [29, 36, 55, 56]. In particular, 3D echocardiography enhances the anatomic visualization of all levels of the AV valve—leaflets, chordae, and papillary muscles (see Chap. 9). Moreover 3D echocardiography is able to display the valve in a manner unavailable by 2D echocardiography, including the en face “surgeon’s view” as described above. In adults, 3D TEE provides a realistic and detailed en face visualization of the individual mitral valve anterior leaflet segments and posterior leaflet scallops [55]. The same holds true for congenital AV valve abnormalities, in which 3D echocardiography (primarily transthoracic, but also TEE) has proven very useful, particularly for endocardial cushion defects (AV canal or AV septal defects) and Ebstein’s anomaly of the tricuspid valve

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

[6, 41, 57, 58]. A number of studies have also discussed the use of 3DE for evaluation of mitral valve disease due to parachute mitral valve [59], double orifice mitral valve [60, 61], mitral valve arcade [62], and congenital mitral regurgitation as well as other mitral valve anomalies. There have also been some recently published studies evaluating the utility 3D echocardiography (both transthoracic and transesophageal) for more precise evaluation of the pathology of congenital AV valve abnormalities, specifically in regard to mechanisms and sites of valve regurgitation [48, 62]. Some examples of 3D TEE for congenital AV valve abnormalities will be discussed below. Despite excellent surgical results for endocardial cushion defects, a disquieting number of patients require re-operation for left AV valve stenosis or regurgitation. In patients that require re-operation for valve regurgitation, 3D imaging provides an excellent perspective of residual regurgitation via clefts in the anterior leaflet, (Fig.  23.13, Video 23.9). The length and position of the residual cleft can be depicted, as well as the precise zones of leaflet prolapse. Intraoperative 3D TEE imaging is used pre and post bypass to evaluate the anatomic extent of residual cleft and associated potential stenosis or regurgitation. Figure  23.13 shows the 3D display, similar to the surgeon’s viewing, i.e. imaging the superior surfaces of the left AV valve from the left atrium. Ebstein’s malformation of the tricuspid valve is a complex anatomic abnormality of the tricuspid valve characterized by nondelamination of the tricuspid valve leaflets (particularly the septal and posterior leaflets) from the under-

a

b

Fig. 23.15  Ebstein’s malformation of the tricuspid valve. Panel (a) is a midesophageal four-chamber view of the heart oriented anteriorly and shows a very large anterior leaflet and severely tethered septal leaflet. Panel (b) is a transgastric short axis plane oriented from the RV apex to base of the heart demonstrating a very large zone of non-coaptation

729

lying myocardium [63–65]. Previous types of valve repair for this anomaly have been associated with variable success [66, 67]. More recently, the “Cone” procedure has gained popularity as a surgical repair of Ebstein’s malformation [68, 69]. In part, the difficulty stems from the fact that surgical management has been predicated on preoperative imaging that does not always clearly depict the anatomic abnormalities. The very complex and variable anatomy of Ebstein’s malformation does not allow for optimal imaging in a standard 2D display. For example, in the most severe form of Ebstein’s malformation the leaflet structures are displaced anterior and superiorly towards the right ventricular outflow tract. The long and ample anterior leaflet billows into  the right ventricle (RV) as it attaches to the RV infundibulum. This is often underappreciated by 2D imaging, but can readily be apparent from full volume 3D echocardiographic data sets obtained from 3D TEE studies (Fig. 23.15, Videos 23.12, 23.13) [41]. Moreover, unusual clefts and attachments from the RV free wall to the anterior leaflet are well-seen with 3D echocardiography (Fig. 23.15a, Video 23.12). Often, a large zone of the regurgitant orifice area can readily be depicted from transgastric  short axis planes oriented from apex to base (Fig. 23.15b, Video 23.12). Similar to aortic and mitral valve repairs, a more dynamic and complete depiction of tricuspid valve leaflet structure and coaptation can readily be seen from 3D TEE when off bypass in the operating room (Fig. 23.15c, Video 23.13). In addition to native AV valve pathology, 3D TEE has been found to be useful for the evaluation of prosthetic AV

c

(Reg Orifice). Panel (c) is post-bypass in the same patient in Fig. 23.15a after the Cone operation. The entire leaflet structure now folds together during systole without a region of non-coaptation. LA left atrium, LV left ventricle, RA right atrium, Reg Orifice regurgitant orifice, RV right ventricle

730

valves (primarily prosthetic mitral valves, see Chaps. 19 and 22) [70]. It allows detailed assessment of valve dehiscence and clot formation. 3D color is especially helpful when evaluating for perivalvar leaks [25, 71].

Evaluation of Semilunar Valves Aortic valve repair,  rather than replacement,  is often preferred in the pediatric patient. Transesophageal and epicardial 3D echocardiography have become useful for the pre-operative assessment of the pediatric or adolescent patient with aortic valve disease, being considered for valve repair [7, 17]. 3D TEE provides important information to determine the precise etiology of valve regurgitation (Fig. 23.14a, Video 23.10). The specific anatomic defect can be seen, and 3D color flow can be applied to further confirm the abnormality (Fig. 23.14b, Video 23.10). 3D imaging provides not only more precise depiction of commissural fusion, but also the more exact site and extent of lack of leaflet coaptation. More importantly, 3D imaging can provide a perspective as to the depth of the valve leaflet, and hence effective areas of leaflet coaptation. 3D TEE can be immediately applied during separation from cardiopulmonary bypass to analyze the integrity of the aortic valve repair (Fig. 23.14c, Video 23.11). This modality demonstrates the effectiveness of leaflet coaptation and opening, visualizing the depth of leaflet integrity. As seen in Fig. 23.14a–c and Videos 23.10, 23.11, the 3D echocardiographic images were oriented to simulate the surgeons view, depicting the superior surfaces of the aortic valve leaflets as if viewed from the aorta (from the surgeon’s perspective). In adult patients with aortic valve stenosis and/or regurgitation, 3D TEE has been shown to provide anatomic detail regarding valve leaflet morphology and function [56, 72, 73]. Furthermore, the ability to obtain en face views of the valve (both above and below the valve) enables the direct planimetry of the aortic valve orifice area [74] in aortic valve stenosis, or vena contracta/regurgitant orifice area in aortic valve regurgitation [75]. The information from 3D TEE can be used to complement that from 2D TEE imaging and 2D color flow and spectral Doppler assessment of the aortic valve (Chap. 13). Combining Doppler velocities of the left ventricular outflow tract (obtained from transgastric or deep transgastric views) with the cross-sectional area of the outflow tract obtained by direct planimetry of the 3D TEE image enables a more accurate calculation of aortic valve area when using the continuity equation. A number of investigators have found the left ventricular outflow tract to be ellipsoid rather than circular in shape, when directly measured by 3D echocardiography (transthoracic or TEE) [29, 76–78]. Thus

P. C. Wong and G. R. Marx

the use of 3D echocardiography likely results in a more accurate calculation of aortic valve area than the method commonly used with 2D echocardiography [79]. There is little information currently available in either the pediatric or adult literature on the use of 3D echocardiography (transthoracic or transesophageal) for the evaluation of congenital pulmonary valve pathology. One report using transthoracic 3D echocardiography in adult patients with congenital RV outflow tract abnormalities demonstrated that the pulmonary valve could be visualized in 70% of patients, but the RV outflow tract in only 40%. However, the anatomic findings, when visible, were useful [80].

 valuation of Atrial and Ventricular Septal E Defects Evaluation of ASDs and VSDs represents a very important clinical application for 3D echocardiography. This is especially true because of the unique en face views of the atrial and ventricular septa that are provided by cropping of the 3D datasets; these views can greatly enhance the understanding of the morphology and extent of the cardiac defects [16, 45, 81–85]. This information is invaluable when planning and performing (monitoring) interventional catheterization procedures [11, 32, 44, 86, 87]. Because of the proximity of the TEE probe to the atrial and ventricular septum, 3D TEE often provides a significantly greater amount of detail compared to transthoracic 3D imaging. Thus, 3D TEE is a natural “fit” for interventional catheterization procedures involving the atrial and ventricular septa. As mentioned, transesophageal 3D imaging can be applied to ASD closure in the catheterization laboratory [32]. The full circumference of the defect can be imaged from the left and right atrium. These en face views allow for depiction of the defect, the rims around the defect, as well as the spatial orientation to other anatomic structures (Fig. 23.16a/b, Videos 23.14 and 23.15). In conjunction with live transesophageal imaging, the procedure of closing the defect can be seen from a 3D perspective. This includes the placement of the sheath in the left atrium as well as unfolding of the device in the left atrium. Under simultaneous visualization, the orientation of the disc to the left atrial surface can be seen in a 3D perspective as the device is maneuvered to the left atrial surface (Fig.  23.16c, Video 23.16). The surface of the disc to the left atrial surface can be depicted prior to deployment. After the left and right atrial discs are deployed, a direct en face view of the disc can be seen to verify the appropriate position (Fig.  23.16d, Video 23.17). The advantages that 3D TEE confers to ASD closure also apply to device closure of VSDs (both percutaneous and per-

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

b

c

d

731

Fig. 23.16  Catheterization device closure of a secundum atrial septal defect (ASD). Panel (a) is a Full Volume acquisition demonstrating an en face view of a secundum ASD from the left atrium. Panel (b) is a Full Volume acquisition of the ASD from the right atrial side demonstrating the relationship to the aorta and superior vena cava  (SVC).

Panel (c) is a live acquisition from the left atrial view demonstrating the sheath placed through the defect and the left atrial disc deployed within the left atrium. Panel (d) is an en face view of the right atrial disc after being deployed. Ao aorta, LA left atrium, RAA right atrial appendage, TV tricuspid valve

ventricular). 3D TEE assists in all phases of the intervention: from pre-procedure evaluation of defect morphology, to catheter positioning and monitoring of device delivery, to relationship of the deployed device to ventricular septum prior to release, and finally device evaluation following com-

plete release. A small but growing body of literature has been published on the use of 3D echocardiography (transthoracic and TEE) for ventricular septal defect device closure [49, 88–90]. Given that standard 2D TEE is already an integral part of these procedures [91–97], it seems likely that 3D TEE

732

Fig. 23.17  En face view of large perimembranous ventricular septal defect from the left ventricle. Ao aorta, LV left ventricle, VSD ventricular septal defect

can only serve to provide additive value in those patients of sufficient size to accommodate the larger probe. In the intraoperative setting, 3D TEE can provide incremental value in the preoperative assessment of VSDs prior to surgery. As noted above, 3D TEE enables visualization of ventricular septal defects in unique en face imaging planes not available by standard 2D imaging (Fig.  23.17, Video 23.18). Although 3D TEE might not seem to add significant additional clinical information for surgical closure, certain unusual defects may need a better definition of the spatial relations of the defect to other anatomic structures. Figure 23.18 is taken from a young adolescent followed for many years with a restrictive VSD. Although suspected by 2D imaging, 3D TEE provided additional imaging projections to improve understanding of the hemodynamic abnormalities. Figure  23.18 and Video 23.19 show the 3D TEE aspects of profound prolapse of the right coronary cusp of the aortic valve through a doubly committed subarterial VSD. The prolapse was so severe that it created moderate RV outflow tract obstruction.

 valuation of Other Congenital Cardiac E Defects Another conundrum in CHD is complex sub-aortic stenosis. The anatomic substrate is often difficult to define and delineate from associated aortic valve disease. Moreover, an important incidence of re-operation for sub-aortic stenosis persists [98, 99]. Much of this difficulty certainly seems to

P. C. Wong and G. R. Marx

Fig. 23.18  Cross sectional view of doubly committed subarterial VSD with prolapse of the right coronary cusp through the defect causing right ventricular outflow tract obstruction. RCC right coronary cusp, RVOT right ventricular outflow tract

be related to less than optimal understanding of this complex anatomy from standard 2D imaging planes. Again, 3D TEE can image the sub-aortic obstruction, in a plane from the left ventricular apex towards the aortic valve (Fig. 23.19, Video 23.20). This view is unavailable to the surgeons unless a left ventriculotomy is performed. The concentric nature of the obstruction, as well as the juxtaposition to the mitral and aortic valve and ventricular septum can be better appreciated in a 3D domain. In older adolescents and young adults who have undergone a myriad of prior surgeries, standard transthoracic imaging may not provide information of sufficient quality to help guide surgical management (due to larger patient size, poorer transthoracic imaging windows, etc.). In such situations, 3D TEE can be employed either as an outpatient procedure, or in the intraoperative setting (before and after cardiopulmonary bypass) to assist in surgical planning and enhance the success of the surgical intervention [100, 101]. The application of 3D TEE to other congenital cardiac defects is still being developed. A number of case reports have described the use of this use of this modality for evaluation of cor triatriatum [102], aortico-left ventricular tunnel [53], corrected and uncorrected transposition of the great arteries [103], and postoperative Fontan [54]. Most of these studies were performed in adult patients with CHD. Interestingly, however, all patients in the Fontan study were 7 years of age or less, underlining the growing use of 3D TEE in the pediatric population.

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

733

b

Fig. 23.19  7 year old male with severe sub-aortic stenosis. Panel (a) is a slightly oblique midesophageal five-chamber view showing the thickened sub-aortic membrane immediately below the aortic valve. Panel (b) is a short axis view oriented from the left ventricular apex to the

aorta, and viewed from the left ventricle perspective, demonstrating the concentric nature of the sub-aortic membrane and corresponding small outflow area. Ao Valve aortic valve

 urther Applications and Development F of 3D TEE

monitor these procedures. The term interventional echocardiography has emerged to describe echocardiography used to support all aspects of cardiac interventions—pre-­ procedure assessment, intraprocedural guidance, and post-­ procedure follow-up. In addition to 2D/3D TEE, interventional echocardiography also includes 2D/3D transthoracic echocardiography, as well as intracardiac echocardiography in some centers [114]. There is considerable potential for the use of 3D TEE in the quantitative analysis of cardiac anatomy, mechanics and function. Similar to CMR, the use of a 3D dataset enables volumetric analysis that avoids the geometric assumptions used with 2D methods such as Simpson’s method of left ventricular volume calculation. To date, most studies evaluating the assessment of left and RV volumes have been performed using transthoracic 3D echocardiography, and have shown promising results. For the LV, a surface-rendered cast of the LV is obtained generally by semi-automated border detection of the LV endocardial-blood interface, although manual tracing is sometimes used. The volume is then calculated by direct voxel count and followed throughout the cardiac cycle (Fig. 23.20, Video 23.21). Calculation of 3D LV volumes and function can also be fully automated. The volumes obtained by 3D echocardiography have been shown to correlate well with CMR, although 3D echocardiography tends to underestimate LV volumes, probably due to its inability to distinguish the trabeculations from LV myocardium [115–117]. Nonetheless, 3D echocardiographic-measured volumes have better reproducibility than 2D echocardiography [115], and therefore would appear to be a better alternative for the volu-

The introduction in 2007 of the first commercially available 3D TEE probe (Philips X7-2t 3D TEE probe), along with the large probe size, have limited its widespread applicability in the pediatric population. Nonetheless as discussed above, the published applications of 3D TEE for CHD have steadily grown, both for use in the operating room and interventional catheterization laboratory, as well as a separate diagnostic modality by itself [4, 42–46, 52, 54, 84, 104–106]. In adults, impressive work has already been performed that explores and extends the use of 3D TEE in a number of settings, including those pertinent to adult CHD patients. This includes its use during cardiac surgery [105, 106] and adult transcatheter procedures, along with diagnostic evaluation of AV and semilunar valve anatomic pathology [25, 36, 105, 107]. Similar to the pediatric population, 3D TEE is used in adults to guide closure of atrial and ventricular septal defects [11, 44, 87, 88, 104, 108]. In addition, 3D TEE has proven integral to a number of transcatheter interventional procedures specific to adult cardiology patients including the following: percutaneous mitral valve edge to edge clip technique [11, 109], mitral balloon valvuloplasty [104], left atrial appendage obliteration [110, 111], transcatheter aortic valve replacement (TAVR) [11, 104, 112], and occlusion of mitral valve perivalvar leaks [11, 37, 113]. The list of these applications is likely to grow significantly in the near future. Echocardiography—in particular 2D/3D TEE—has emerged as the essential imaging technology required to assess and

734

P. C. Wong and G. R. Marx

a

b

Fig. 23.20  Quantitative assessment of left ventricle (LV) volume and systolic function using three-dimensional (3D) echocardiography. (a) From a transthoracic 3D echocardiographic data set of the LV (left panel), the LV endocardium can be traced (middle panel, top) to obtain the LV volume throughout the cardiac cycle (right panel, top). Using the maximum and minimum volumes obtained from this curve, an ejection fraction can be calculated. As well, the LV endocardium can be divided according to the 17-segment mode (middle panel, bottom), and the time each segment requires to attain minimal volume in the cardiac cycle can

be identified (right panel, bottom). Reprinted from Lang et al. [28], with permission from Elsevier. (b) Evaluation of LV systolic function and dyssynchrony. The upper left and right panels show the 3D surface-­ rendered LV volume from two views. The bottom left panel shows an example of the 16 segment model. Calculation of systolic dyssynchrony index (SDI) can automatically be performed using the 16 segment (SDI 16) and 17 segment (SDI 17) models (bottom right panel). See text for details

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

735

metric assessment of the LV. Fully automated quantification of 3D LV volumes (as well as left atrial volumes) is now available on several echocardiography platforms [118] (Fig. 23.21, Video 23.22). Assessment of RV volumes/function can also be performed by generation of a surface-rendered cast of the RV, usually by semiautomated border quantification using specialized offline software (TomTec 4D echo analysis software, Tom Tec Imaging Systems GmbH, Munich, Germany) (Fig. 23.22, Video 23.23). This analysis can be more involved because of the unusual geometry and shape of the RV. Using this method, published studies have shown a good correlation between 3D transthoracic echocardiography and CMR with respect to RV volumes and function [119–121]. However like the 3D evaluation of LV, there appears to be an underestimation of RV volume by 3D echocardiography compared to CMR [122]. Studies evaluating 3D TEE assessment of left and RV volumes have yet to be performed extensively with 3D TEE [25], but it seems likely that similar results can be obtained with this modality as well. In fact, the superior imaging quality of TEE might actually enhance volume and function assessment in larger patients. Several recent studies have demonstrated the ability of intraoperative 3D TEE to obtain adequate images for subsequent offline measurement of LV/RV volume and function, using images obtained from the midesophageal window and the same methods of semiautomated border detection [123, 124].

Even more sophisticated evaluations of cardiac mechanics and function have been reported in adults with the use of 3D echocardiography. These evaluations are valuable because they can be difficult to obtain by 2D methods. 3D Echo has been shown to be useful for evaluation of LV segmental wall motion analysis and dyssynchrony (Fig. 23.23). Using either a 16 segment model (American Society of Echocardiography) or 17 segment model (American Heart Association) [125], a systolic dyssynchrony index (SDI) can be calculated as the standard deviation of the time required to reach minimum systolic volume for each segment as a percentage of the cardiac cycle (Fig. 23.20b). For normal subjects, the mean SDI (16 segment model) is 3.5 ± 1.8% [126]. This 3D model of dyssynchrony can be used as one of the measures to evaluate the results of cardiac resynchronization therapy [127–132]. Using readily available offline 3D software (QLABS from Philips Medical Systems; TomTec 4D echo analysis software, Tom Tec Imaging Systems GmbH, Munich, Germany), quantitative assessment of linear and area measurements can be performed on 3D transthoracic and TEE datasets, along with detailed mitral and aortic valve analysis. The latter includes evaluation of noncircular vena contracta (Fig. 23.24) in mitral regurgitation [133], and planimetry of anatomic regurgitant orifice area in mitral ­regurgitation and stenotic orifice area in mitral stenosis [134, 135]. Recently, 3D TEE has enabled sophisticated evaluation

Fig. 23.21  Automated quantification of left ventricular and left atrial volumes and function (HeartModel, Philips Medical Systems). For the left ventricle, in addition to ejection fraction, cardiac index is also cal-

culated based upon calculated indexed stroke volume and heart rate. For the left atrium, index left atrial volume as well as emptying fraction are calculated

736

P. C. Wong and G. R. Marx

Fig. 23.22 Quantitative assessment of right ventricular (RV) volume and systolic function using three-dimensional (3D) echocardiography, using software from TomTec (4D RV-function©). From a full volume transthoracic 3D echocardiographic data set of the RV, the endocardium is manually traced in three orthogonal planes to obtain the RV. The software utilizes a semi-automated border detection method to generate a dynamic model of the RV, which is displayed in the top panel. RV volume is displayed on a curve of volume over time throughout the cardiac cycle in the lower left panel. The RV stroke volume (SV) and ejection fraction (EF) are automatically calculated and displayed in the lower right panel

of mitral valve parametric mapping [136] and volumetric quantification [29], aortic root reconstruction, as well as mitral, aortic, and tricuspid annulus evaluation (Fig. 23.25), aortic valve dynamic motion [29, 38], and mitral-aortic valve coupling [137]. An important disadvantage of most of the aforementioned analyses (including volume/function quantification) is that they must be performed offline and the analysis can be rather time-consuming, thus limiting their immediate utility in the intraoperative and interventional cardiology settings where rapid access to information is essential [138]. However, 3D echocardiography systems are rapidly advancing, and future advances in semi-automated quantification, as well as on-cart availability of analysis tools, could make many of the quantitative 3D TEE analyses readily accessible at the time of the study. One report of 3D TEE during a Ross procedure demonstrated the use of 3D volumetric and function quantification before and after cardiopulmonary bypass (using techniques described above); the authors were able to quantify LV function and identify wall motion abnormalities following bypass [72]. A 3–5 min time period was needed for quantification, and this short

period of time allowed it to be performed contemporaneously with the operation. The other important consideration pertains to the use of 3D TEE for quantitative analysis of cardiac mechanics and function in patients with CHD. The evaluations of right and single ventricle volumes and function are currently some of the most important and active areas of investigation among CHD specialists. These types of evaluation are pertinent for a number of important and topical issues in CHD: RV ­function in postoperative tetralogy of Fallot patients with chronic pulmonary regurgitation, ventricular function in various forms of single ventricle/Fontan patients, function of the systemic RV in congenitally corrected transposition of the great arteries, etc. Currently CMR is the gold standard for quantification of ventricular volumes and function in these settings, but a number of pediatric studies have shown a reasonably good correlation between 3D echocardiography and CMR in volumes and function for the LV [139–144], RV [121, 123, 145–147], and even single ventricles [148, 149]. These studies were performed primarily with transthoracic 3D echocardiography, and it remains to be seen how useful

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

737

a

Fig. 23.23  Evaluation of left ventricle (LV) segmental wall motion. (a) Shows a three-dimensional transthoracic echocardiogram data set of the left ventricle as viewed from the apex (left, top) or anteriorly (right, top), with dynamic tracking of the LV endocardium. The end-diastolic LV endocardium is visualized as a mesh shell and the end-systolic endocardium as a solid shell. Lower left: a seventeen-segment, bull’s-­ eye map of contraction front mapping demonstrating the time required for each segment to reach minimal LV volume (left, bottom). Lower

right: Graph, with time along the x axis and volume along the y axis, demonstrating the time for each segment to reach minimal volume (right, bottom). Ant, Anterior; Inf, inferior; Lat, lateral; Sept, septum. Reprinted from Lang [28], with permission from Elsevier. Panel (b) is taken from a patient with dilated cardiomyopathy and dyssynchronous LV contraction; note the marked lack of synchrony of the individual cardiac segments as compared to Fig. 23.23a

and effective 3D TEE will be in this setting. This represents one of the many areas of research in 3D echocardiography. Another interesting area for future development is the use of 3D color flow Doppler (3D CFD) for evaluation of CHD. As noted earlier in this chapter, 3D CFD is used quali-

tatively for assessment of AV and semilunar valve pathology, to localize and display sites of stenosis or regurgitation. In addition, 3D CFD has been utilized in CHD as an “echocardiographic angiogram” to assess vascular structures such as coarctation, vascular ring, and systemic to pulmonary artery

738

P. C. Wong and G. R. Marx

b

Fig. 23.23 (continued)

shunts [150]. Quantitative use of 3D CFD also holds some promise as a method of volumetric flow assessment [151]. A study by Poh et  al. evaluated cardiac output in sheep with experimentally distorted ventricular septal geometry, and found that, using flow-probe data as a reference standard, a much better correlation was obtained when calculated by 3D CFD as compared to 2D-derived methods [152]. Lu et  al. have compared the use of 3D CFD to 3D ventricular volumetric calculations as a method for measurement of valvar

volumetric flow in children. These investigators found the best correlation with the mitral valve, good correlations for aortic and pulmonary valves, and a poor correlation with the tricuspid valve [153]. Nonetheless, despite the encouraging data from these studies, more investigation will need to be performed to verify the utility of 3D CFD, especially given the potentially limiting factors of 3D CFD including smaller volume datasets, stitch artifact, and marginal spatial/temporal resolution. Improvements in 3D CFD technology, along

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

b

c

d

Fig. 23.24  Example of measurement of vena contracta (VC) dimensions in a cross-sectional plane through the VC in a patient with functional mitral regurgitation caused by leaflet tethering. Panel (a) shows a four-chamber view with measurement of a narrow VC width in the four chamber view. Panel (b) shows a two-chamber view with measurement of a broad VC width. Panel (c) shows a cross-sectional plane through the VC with direct planimetry of vena contracta area. The green and the

739

red lines indicate the orientation of the four chamber plane (panel a, green frame) and the two chamber plane (panel b, red frame). Panel d shows a 3D en face view of VC area. Note that the significant asymmetry of the VC area makes difficult the accurate assessment of regurgitation from a single plane. Reprinted from Kahlert et al. [133], with permission from Elsevier)

740

P. C. Wong and G. R. Marx

Fig. 23.25  Three-dimensional imaging allows reconstruction of native valve annuli by using specialized software from which area, perimeter, dimensions, and eccentricity can be measured. The left column shows

analysis of the aortic valve, the middle column mitral valve, and the right column tricuspid valve. Reprinted from Lang et  al. [118], with permission from Elsevier

with more robust semi-automated flow quantification tools, will likely enhance the utility of these techniques [58]. Another important recent area of development for interventional echocardiography is the merging of 3D TEE and fluoroscopy, also known as fusion imaging. This technique performs a synchronization and co-registration of TEE position and orientation with fluoroscopy, and the real-time TEE image is superimposed on the fluoroscopic image. This technique has been used for adult interventional procedures (such as the MitraClipTM, Abbott Laboratories) as well as interventions for CHD [32, 154] (Fig. 23.26).

The growth in the popularity and applicability of 3D TEE for a number of different applications (particularly to support the profusion of new devices and applications for interventional cardiology) has resulted in widespread availability of adult 3D TEE probe technology. All major echocardiography companies now offer an adult 3D TEE probe as a standard option. However, to date there has not yet been the commercial release of pediatric 3D TEE probe, although this will be one of the next major goals in the evolution of TEE technology [155] (see Chap. 2).

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

Fig. 23.26  Example of fusion imaging of the mitral valve using 3D transesophageal echocardiography and fluoroscopy, as shown from the right anterior oblique (a) and left anterior oblique (b) projections. The mitral valve anterior leaflet segments and posterior leaflet scallops can

741

b

be seen. CS coronary sinus, LC lateral commissure, MC medial commissure. From Faletra et  al. [154], with permission from Oxford University Press

 D Imaging: Limitations, Artifacts, 3 and Pitfalls Despite its growing popularity, 3D imaging still has important potential limitations with which the examiner should be aware. First, despite the dramatic advances in 3D technology, both spatial and temporal resolutions are still inferior to that of comparable 2D imaging. The 3D TEE probe images at the same high frequency (7 MHz) as many adult TEE probes as well as some pediatric transthoracic probes, but some degree of fine gray scale and tissue detail are lost when imaging in 3D. Temporal resolution is also reduced (sometimes significantly) when compared to 2D imaging, and this can impair the ability to visualize precise motion of structures such as AV and semilunar valves. It can also be a potential issue in younger patients with faster heart rates; the lower volume rates can result in cardiac motion that appears less smooth. Since 3D echocardiography is still a form of ultrasound, it will be subject to the same artifacts as those encountered with 2D echocardiography, such as reverberations and shadowing. In addition, there are some artifacts particular to 3D imaging. Such artifacts include false dropout of certain areas due to lack of 3D data collected by the matrix transducer. This can also occur because of reduced gain settings that lead to data loss. The result is transparency or apparent absence of tissue in certain structures such as the AV and semilunar valves. In some cases, the dropout can mimic an anatomic defect. It can also become apparent when nonstandard cropping planes are used, due to the data loss that can occur from objects oriented

Fig. 23.27  Example of stitch artifact with a full volume dataset. This can occur as a result of irregularities in cardiac rhythm, or respiratory/ patient movement

more parallel to the ultrasound beam(s) [156]. To compensate, gain settings can be increased, but too much gain will lead to speckling artifacts and worsened 3D rendering that can obscure cardiac structures. Another important artifact is the “stitch artifact” (described above) that can occur with full volume imaging, due to irregularities in ECG gating and/or movement of the cardiac position from respiration or other external factors (Fig. 23.27, Video 23.24). This can introduce errors in the depiction of real-time motion [29].

742

The other important point is that the 3D images actually represent 2D renderings of 3D structures, with color shading used to give the perception of depth. While 3D TEE images provide excellent detail, it can be difficult to determine the precise front to back spatial orientation of cardiac structures in a given 3D image. These 3D relationships can be particularly important with CHD. Thus it is important to perform both cropping and rotation of a 3D rendering, and to visualize a cardiac structure in several different views [29]. The use of promising new technologies such as 3D printing, virtual reality, and holography present exciting new methods that have the potential to enable a more realistic appraisal of the anatomy obtained by 3D echocardiography (both transthoracic and transesophageal) [157–163].

Summary 3D TEE has become an integral part in the evaluation and management  of patients with complex CHD at many centers  that care for these patients. Such imaging provides unique planes and projections that are unavailable with standard 2D display. Moreover, in pre and post bypass patients the heart and corresponding anatomy is depicted in dynamic motion, rather than the surgeon’s perspective of the non-­ beating heart. Certain aspects will need to continue to evolve, for example improved imaging in the near field is necessary. Transesophageal probes need to be made smaller, with higher transmit frequencies for the smaller pediatric patients. Live full volume imaging will be more advantageous with improved temporal resolution (for the faster heart rates in children) and overall improved spatial resolution. Also, the ability to perform online linear, area and volume measurements directly on the echocardiography machine will facilitate the ability to provide timely important information to surgeons and interventional cardiologists. This will be further enhanced by automated quantification tools that are now appearing on the advanced 3D echocardiography platforms. Equally important for successful development of 3D TEE imaging are the interactions between the cardiologist and surgeon in trying to comprehend and display this complex anatomy. Intraoperative 3D TEE imaging can be challenging due to the constraints of time in the operating room, as well the importance of surgeon comprehension of the rendered 3D images. Optimal communication and cooperation among the cardiologist, surgeon, and anesthesiologist are paramount.

P. C. Wong and G. R. Marx

Case-Based Examples Case #1 Subject:  Intramyocardial left anterior descending coronary artery arising from the right sinus of Valsalva Clinical History:  15-year-old female with history of no symptoms, but found on routine surveillance echocardiogram to have origin of the left main coronary artery from the right sinus of Valsalva. Nuclear stress test showed moderate fixed perfusion abnormality in the mid-distal anteroseptal wall. CT angiogram and cardiac MRI confirmed the anomalous origin. In surgery, the pulmonary valve was explanted, the left anterior descending coronary artery was unroofed, and the entire main pulmonary artery/pulmonary valve were translocated to the right ventricular outflow tract below the level of the anterior descending coronary artery.

TEE Findings: Preoperative TEE. The 2D TEE from a midesophageal aortic valve short axis view shows the right coronary artery and left anterior descending (LAD) coronary arising from a common origin off the aortic right sinus of Valsalva. However, instead of traversing between the aorta and main pulmonary artery, as is more commonly seen with anomalous origin of the left coronary artery from the right sinus of Valsalva (see Chap. 17), the LAD courses inferiorly (Fig.  23.28, Video 23.25), and enters the myocardium through the infundibular septum. It travels to the left and just inferior to the pulmonary valve, as shown by 3D TEE (Fig. 23.29, Video 23.26) and follows the curve of the infundibulum/ventricular septum before turning superiorly and anterior to emerge on the epicardial surface of the heart, to the left of the main pulmonary artery. After reaching the surface, it then travels inferiorly to follow the plane of the ventricular septum. Postoperative TEE. The 3D TEE shows that the main pulmonary artery and pulmonary valve have been anastomosed to the right ventricular outflow tract below (inferior) to the level of the left anterior descending (arrow) (Fig. 23.30 and Video 23.27). Discussion:  This is an unusual variation of anomalous origin of a coronary artery. Instead of coursing between the two great arteries, in which the coronary artery takes an interarterial and often intramural course, in this case the LAD takes an intramyocardial course through the ventricular septum. This entity is rare but has been described. In this patient, 3D TEE demonstrates the more inferior course of the LAD

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

743

b

Fig. 23.28  Case #1. (a) This midesophageal aortic valve short axis view shows the right coronary artery (RCA) and left anterior descending (LAD) coronary arising from a common origin off the aortic right sinus of Valsalva. (b) Instead of traversing between the aorta (Ao) and

main pulmonary artery (PA), as is more commonly seen with anomalous origin of the left coronary artery from the right sinus of Valsalva (see Chap. 17), the LAD courses inferiorly and enters the myocardium through the infundibular septum (arrow). RV right ventricle

Fig. 23.29  Case #1. This 3D TEE shows the left anterior descending (LAD) coursing inferiorly and entering the myocardium through the infundibular septum. It travels to the left and just inferior to the pulmonary valve (PV) and follows the curve of the infundibulum/ventricular septum before turning superiorly and anteriorly to emerge on the epicardial surface of the heart, to the left of the main pulmonary artery. Ao aorta/aortic valve

Fig. 23.30  Case #1. The 3D TEE shows that the main pulmonary artery (PA) and pulmonary valve have been anastomosed to the right ventricular (RV) outflow tract below (inferior) to the level of the left anterior descending coronary artery (arrows). This contrasts with the preoperative study, in which the artery was the pulmonary valve was located superior to the left anterior descending coronary artery

through the ventricular septum, thereby providing a more complete 3D display of the spatial orientation of the LAD than would be available by 2D TEE alone.

of Valsalva with a septal course: an explanation to disabling angina? Int J Cardiol. 2011;151(2):e74–6.

Suggested Readings/References Johnson JN, Bonnichsen CR, Julsrud PR, Burkhart HM, Hagler DJ. Single coronary artery giving rise to an intraseptal left coronary artery in a patient presenting with neurocardiogenic syncope. Cardiol Young. 2011;21(5):572–6. Mogensen UM, Grande P, Kober L, Kofoed KF. Anomalous origin of the left main coronary artery from the right sinus

Case #2 Subject:  Subaortic stenosis in a patient with unbalanced AV canal, post-Fontan procedure Clinical History:  The patient is a 7-year-old male with unbalanced AV canal, hypoplastic LV, status post bidirectional Glenn and nonfenestrated extracardiac Fontan proce-

744

dure, who was noted to have increasing subaortic obstruction. An outpatient TEE was performed to evaluate the nature of the subaortic obstruction, in consideration of cardiac surgery. Both 2D and 3D TEE were performed (see below).

TEE Findings: The 2D TEE images using a midesophageal four-chamber view (Fig. 23.31, Video 23.28) demonstrate the unbalanced,

Fig. 23.31  Case #2. Midesophageal four-chamber 2D TEE view demonstrating an unbalanced, right dominant AV canal as well as a very hypoplastic left ventricle (LV). LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

Fig. 23.32  Case #2. Midesophageal long axis 2D TEE view color compare mode, demonstrating subaortic stenosis. The color flow Doppler shows aliasing (turbulence) beginning below the aortic valve (AoV). The AoV leaflets are not well-seen on this study. LA left ventricle, LV left ventricle

P. C. Wong and G. R. Marx

right dominant AV canal as well as the very hypoplastic LV, and Video 23.38 shows that aorta arising from the LV with significant turbulence below the aortic valve noted by color flow Doppler. The midesophageal long axis view (Fig. 23.32, Video 23.29), using color flow Doppler, notes turbulence and narrowing below the aortic valve. The deep transgastric view using a transducer angle 39° (Fig. 23.33, Video 23.30) clearly shows an en face view of the unbalanced, right dominant AV valve, with right to left shunting across the ventricular septal defect (VSD) and subaortic narrowing with turbulent flow noted by color flow Doppler (as well as a trivial amount of aortic regurgitation); continuous wave spectral Doppler across this area measures a peak velocity of approximately 2.5 m/sec (25 mm Hg). The 3D TEE images are obtained from several different perspectives. The first perspective is a frontal view simulating a modified midesophageal four-chamber view (Fig. 23.34, Video 23.31). This shows the right dominant AV canal with the AV valve emptying primarily into the RV.  Video 23.31 also displays a posterior to anterior crop that demonstrates the aortic valve arising from the LV. The second perspective (Fig.  23.35, Video 23.32) is obtained from the RV chamber perspective with an en face view of ventricular septum and VSD.  AV valve chordae are seen attaching to the crest of the VSD and partially covering the defect (Fig.  23.36, Video 23.33). The third perspective is from the LV chamber (Figs.  23.37, Video 23.34). and another en face view of the VSD is visible, as well as the aortic valve arising from the LV.  In this view, significant

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

745

Fig. 23.33  Case #2. Deep transgastric 2D TEE view color compare mode (transducer angle 39°) shows an en face view of the unbalanced, right dominant AV valve, with right to left shunting across the ventricular septal defect and subaortic narrowing with turbulent flow noted by color flow Doppler. The aortic valve (AoV) arises from the hypoplastic left ventricle (LV). RV right ventricle

Fig. 23.34  Case #2. 3D TEE using a frontal view that simulates a modified midesophageal four-chamber view. The hypoplastic left ventricle (LV) is shown. LA left atrium, RA right atrium, RV right ventricle

subaortic narrowing is produced by the infundibular septum, and color flow Doppler clearly shows turbulence (aliasing) beginning at this level. Based upon the TEE findings, the patient underwent cardiac surgery in which crossing chordae were noted across the AV canal-type ventricular septal defect (VSD), as well as

Fig. 23.35  Case #2. This 3D TEE is obtained from the perspective of the right ventricular (RV) chamber with an en face view of ventricular septum and ventricular septal defect (VSD). AV valve chordae are seen attaching to the crest of the VSD, partially covering the defect. LA left atrium, RA right atrium

muscular narrowing produced by the infundibular (conal) septum. The infundibular septum was partially resected, and the VSD enlarged, and this led to relief of the subaortic stenosis.

746

a

Fig. 23.36  Case #2. 3D TEE obtained from a left ventricle (LV) perspective. (a) An en face view of the VSD is visible , as well as the narrowed LV outflow tract. . (b) Significant subaortic narrowing is

P. C. Wong and G. R. Marx

b

produced by the malaligned infundibular septum below the aortic valve (AoV). Note: In this figure, a positional compass has been added to help orient the reader

ing of the large common AV valve, its attachments to the crest of ventricular septum, and the complex nature of the subaortic obstruction. This in turn was very helpful to the surgeon, facilitating the development of a detailed and specific surgical plan to alleviate the obstruction.

Fig. 23.37  Case #2. 3D TEE color flow Doppler shown from a similar perspective as Figure 23.26b. The subaortic narrowing results in aliasing (turbulence) at the level of the malaligned infundibular septum. AoV aortic valve, LV left ventricle. Note: In this figure, a positional compass has been added to help orient the reader

Discussion:  This study shows how both 2D and 3D TEE help to elucidate the mechanism of subaortic obstruction in this patient with a functional single ventricle and subaortic stenosis. The 3D TEE provides a more complete understand-

Suggested Readings/References Gripari P, Tamborini G, Barbier P, Maltagliati AC, Galli CA, Muratori M, et  al. Real-time three-dimensional transesophageal echocardiography: a new intraoperative feasible and useful technology in cardiac surgery. Int J Cardiovasc Imaging. 2010;26:651–60. Sung TY, Kwon WK, Park DH, Park CH, Kim TY.  Intraoperative three-dimensional transesophageal echocardiography for evaluating an unusual structure in the left ventricular outflow tract: a case report. Korean J Anesthesiol. 2015 Oct;68(5):505–8. Simpson J, Lopez L, Acar P, Friedberg MK, Khoo NS, Ko HH, et  al. Three-dimensional Echocardiography in Congenital Heart Disease: An Expert Consensus Document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30(1): 1–27.

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

Fig. 23.38  Case #3. (a) This is a 3D Zoom image cropped to display an en face view of the atrial septal defect as seen from the right atrium. A positional compass has been included for orientation. (b) From the

747

b

same dataset, the diameters of the atrial defect can be measured. SVC superior vena cava, IVC inferior vena cava

Case #3 Subject:  Transcatheter atrial septal defect closure Clinical History:  A 16 year old female with a secundum atrial septal defect (ASD) was brought to the cardiac catheterization laboratory, with the intent to perform transcatheter ASD closure primarily using 2D and 3D TEE guidance.

TEE Findings: Both 2D and 3D TEE were performed to evaluate the ASD, which was oval in shape, measuring 10 × 11 mm in diameter There were excellent rims for closure (Figs. 23.38 and 23.39, Videos 23.35 and 23.36). Using 3D TEE, a catheter was advanced into the superior vena cava and then into the main pulmonary artery (Fig. 23.40, Video 23.37), to evaluate right sided pressures and calculate the left to right shunt fraction. Using primarily 3D TEE, the catheter was then advanced across the atrial septum, and a 30 mm GORE® Cardioform septal occluder device was implanted (Fig.  23.41, Video 23.38). Following device implantation, no residual atrial shunting was noted by 2D TEE (Fig.  23.42, Video 23.39), and there was no evidence of systemic or pulmonary venous obstruction. Finally, by 3D TEE, the device was noted to be in excellent position (Fig. 23.43, Video 23.40).

Fig. 23.39  Case #3. 3D Zoom dual volume image of the atrial septal defect. The dataset is sectioned through a central plane display and then opened into two “halves” to display an en face view of the defect as seen from the right and left atrial perspectives

Discussion:  This case demonstrates that 2D and 3D TEE can be used as the primary imaging modality to guide ASD device closure in the catheterization laboratory. During implantation, real-time 3D TEE was utilized to direct catheter placement and then device implantation. Both Live 3D and 3D Zoom mode (including dual volume 3D) were best utilized because of the need for rapid, real-time image information regarding catheter and device positioning. This type of approach is representative of the field of Interventional

748

a

P. C. Wong and G. R. Marx

b

Fig. 23.40  Case #3. Intracardiac catheter placement as visualized by 3D TEE. (a) The catheter has been advanced from the inferior vena cava to superior vena cava (SVC), using the 3D equivalent of the midesophageal bicaval view. The atrial septal defect is partially visible. (b)

The catheter has been advanced through the right ventricle (RV) into the main pulmonary artery (MPA) using the 3D equivalent of the midesophageal RV inflow-outflow view. Ao aorta, LA left atrium, RA right atrium

Fig. 23.41  Case #3. 3D Zoom dual volume showing the delivery of the occluder. The left atrial portion of the device (arrow) has been opened

Fig. 23.43  Case #3. 3D Zoom dual volume following complete release of the atrial device. The device is well-seated on both sides of the atrial septum

Echocardiography, in which the echocardiographer plays an integral role during transcatheter interventions.

Fig. 23.42  Case #3. 2D TEE using a midesophageal bicaval view that shows the atrial device to be very well-seated, flush against both sides of the septum, with no residual left to right shunting across the device. There is no obstruction to flow return from the superior and inferior vena cavae

Suggested Reading/References Baker GH, Shirali G, Ringewald JM, Hsia TY, Bandisode V.  Usefulness of live three-dimensional transesophageal echocardiography in a congenital heart disease center. Am J Cardiol. 2009;103(7):1025–8. Simpson J, Lopez L, Acar P, Friedberg MK, Khoo NS, Ko HH, et  al. Three-dimensional Echocardiography in Congenital Heart Disease: An Expert Consensus Document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30(1):1–27.

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

749

b

Fig. 23.44  Case #4. 3D images of aortic root replacement using aortic valve-sparing technique. (a) The left coronary artery (LCA) button, the ribbed Hemashield graft, and the tailoring of the inferior portion of the graft to the aortic valve annulus (AoV). (b) The right coronary artery

(RCA) button, the Hemashield graft, and the tailoring of the inferior portion of the graft to the AoV. These images demonstrate the level of anatomic 3D detail that is not readily apparent with standard 2D imaging

Jone PN, Zablah JE, Burkett DA, Schafer M, Wilson N, Morgan GJ, et al. Three-Dimensional Echocardiographic Guidance of Right Heart Catheterization Decreases Radiation Exposure in Atrial Septal Defect Closures. J Am Soc Echocardiogr. 2018;31(9):1044–9. Rat N, Muntean I, Opincariu D, Gozar L, Togănel R, Chițu M.  Cardiovascular Imaging for Guiding Interventional Therapy in Structural Heart Diseases. Curr Med Imaging Rev. 2020;16(2):111–22.

study). The 3D TEE showed excellent images of the Hemashield graft, the anastomosis between Hemashield graft and aortic valve, as well as the reimplanted right and left coronary artery buttons (Fig.  23.44, Videos 23.41 and 23.42). Certain 3D anatomic features of the repair are shown with a level of detail that is not readily apparent with standard 2D echocardiographic imaging—the ribbed and curved texture of the Hemashield graft, the tailoring of the graft to the aortic valve annulus, and the circular configuration of the coronary artery buttons.

Case #4 Subject:  Valve-sparing aortic root replacement Clinical History:  A 15 year old male with Loeys-Dietz syndrome underwent cardiac surgery to address the development of significant aortic root dilation. In surgery, a valve sparing procedure was performed using a 26  mm Hemashield vascular graft to replace the aortic root. The patient’s own aortic valve was implanted inside the graft, and the explanted coronary artery buttons were reimplanted onto the graft. Intraoperative 2D and 3D TEE are performed to assess aortic valve function, coronary artery patency, competency and patency of the graft, as well as cardiac filling and function.

TEE Findings: The aortic valve demonstrated normal aortic valve function and normal biventricular systolic function (not shown on this

Suggested Reading/References Otani K, Takeuchi M, Kaku K, Sugeng L, Yoshitani H, Haruki N, et al. Assessment of the aortic root using realtime 3D transesophageal echocardiography. Circ J. 2010;74(12):2649–57. Williams JB, McCann RL, Hughes GC. Total aortic replacement in Loeys-Dietz syndrome. J Card Surg. 2011 May;26(3):304–8. David TE.  Aortic Valve Sparing in Different Aortic Valve and Aortic Root Conditions. J Am Coll Cardiol. 2016;68(6):654–64. Nowak-Machen M.  The role of transesophageal echocardiography in aortic surgery. Best Pract Res Clin Anaesthesiol. 2016 Sep;30(3):317–29. MacCarrick G, Black JH 3rd, Bowdin S, El-Hamamsy I, Frischmeyer-Guerrerio PA, Guerrerio AL, Sponseller PD, Loeys B, Dietz HC 3rd. Loeys-Dietz syndrome: a primer for diagnosis and management. Genet Med. 2014 Aug;16(8):576–87.

750

Questions and Answers 1. Of the following, which represents the scenario most likely to benefit from 3D TEE? a. 3 day old neonate with transposition of the great arteries, undergoing arterial switch operation b. 1 year old infant undergoing tetralogy of Fallot repair c. 15 year old undergoing secundum atrial septal defect (ASD) closure in the cardiac catheterization laboratory d. 18 year old undergoing coarctation stent placement in cardiac catheterization laboratory e. 10  year patient with superior vena cava stenosis, undergoing dilation in the cardiac catheterization laboratory. Answer: c Explanation: 3D TEE is useful for interventional closure of secundum ASDs, and can play an important role. It is not indicated for coarctation stent placement or superior vena cava dilation. The currently available adult 3D TEE probes would not be feasible in a neonate or young infant. 2. “Stitch” artifact is most apparent in which of the following data acquisition modes for 3D TEE? a. Real-time (Live) 3D b. 3D Zoom c. 2D simultaneous multiplane mode d. ECG-gated multi-beat acquisition e. Single beat full volume Answer: d Explanation: Stitch artifact occurs when several subvolumes are collected sequentially and then “stitched” together to create a larger volume dataset. If the ECG gating is not exact (for example, due to variation in R-R interval), or there is patient motion, the subvolumes will not be perfectly synchronized, and stitch artifact can occur. The other modes do not involve stitching together subvolumes, and therefore they are not subject to stitch artifact. 3. Which of the following is the proper display of the “surgeon’s view” of the mitral valve from a 3D dataset? a. Mitral valve viewed from left atrium, aortic valve at 2 o’clock b. Mitral valve viewed from left atrium, aortic valve at 7 o’clock c. Mitral valve viewed from left ventricle, aortic valve at 11 o’clock d. Left ventricle cropped from the lateral wall to visualize the mitral valve

P. C. Wong and G. R. Marx



e. Left ventricle cropped from the ventricular septum to visualize the mitral valve from the left ventricular outflow tract.

Answer: a Explanation: The “surgeon’s view” is by definition an en face view of the mitral valve as viewed from the left atrium. By convention, when the mitral valve is viewed as a clock face, the aortic valve is located at about the 2 o’clock position. 4. Which of the following echocardiographic modalities is available on a 2D multiplane TEE probe but not a 3D TEE probe? a. 2D imaging b. M-mode imaging c. 2D color flow Doppler d. Continuous wave Doppler e. All of the above are available on a 3D TEE probe Answer: e Explanation The 3D TEE probe provides all the capabilities of a standard 2D multiplane TEE probe. 5. The standard 3D TEE Matrix probe has approximately how many elements? a. 64 b. 128 c. 256 d. 1500 e. 2500 Answer: e Explanation: The 3D TEE Matrix probe has a square grid of 50 x 50 elements, or 2500 total.

References 1. Belohlavek M, Foley DA, Gerber TC, Greenleaf JF, Seward JB.  Three-dimensional ultrasound imaging of the atrial septum: normal and pathologic anatomy. J Am Coll Cardiol. 1993;22(6):1673–8. 2. Marx GR, Fulton DR, Pandian NG, Vogel M, Cao QL, Ludomirsky A, et al. Delineation of site, relative size and dynamic geometry of atrial septal defects by real-time three-dimensional echocardiography. J Am Coll Cardiol. 1995;25(2):482–90. 3. Franke A, Kühl HP, Rulands D, Jansen C, Erena C, Grabitz RG, et al. Quantitative analysis of the morphology of secundum-type atrial septal defects and their dynamic change using transesophageal three-dimensional echocardiography. Circulation. 1997;96(9 Suppl):II-323–7. 4. Cao Q, Radtke W, Berger F, Zhu W, Hijazi ZM. Transcatheter closure of multiple atrial septal defects. Initial results and value of

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease two- and three-dimensional transoesophageal echocardiography. Eur Heart J. 2000;21(11):941–7. 5. Mumm B, Nanda NC, Sorrell VL. Technical background and current and future aspects of three-dimensional echocardiography. In: Nanda NC, Sorrell VL, editors. Atlas of three-dimensional echocardiography. Armonk, NY: Futura Publishing; 2002. p. 1–20. 6. Miller AP, Nanda NC, Aaluri S, Mukhtar O, Nekkanti R, Thimmarayappa MV, et  al. Three-dimensional transesophageal echocardiographic demonstration of anatomical defects in AV septal defect patients presenting for reoperation. Echocardiography. 2003;20(1):105–9. 7. Vida VL, Hoehn R, Larrazabal LA, Gauvreau K, Marx GR, del Nido PJ.  Usefulness of intra-operative epicardial three-­ dimensional echocardiography to guide aortic valve repair in children. Am J Cardiol. 2009;103(6):852–6. 8. Salandin V, De Castro S, Cavarretta E, Salvador L, Papetti F, Valfrè C, et  al. Epicardial real-time 3-dimensional echocardiography with the use of a pediatric transthoracic probe: a technical approach. J Cardiothorac Vasc Anesth. 2010;24(1):43–50. 9. Sugeng L, Shernan SK, Salgo IS, Weinert L, Shook D, Raman J, et al. Live 3-dimensional transesophageal echocardiography initial experience using the fully-sampled matrix array probe. J Am Coll Cardiol. 2008;52(6):446–9. 10. Sugeng L, Weinert L, Lang RM.  Left ventricular assessment using real time three dimensional echocardiography. Heart. 2003;89(Suppl 3):iii29–36. 11. Perk G, Lang RM, Garcia-Fernandez MA, Lodato J, Sugeng L, Lopez J, et al. Use of real time three-dimensional transesophageal echocardiography in intracardiac catheter based interventions. J Am Soc Echocardiogr. 2009;22(8):865–82. 12. Mackensen GB, Swaminathan M, Mathew JP.  PRO editorial: PRO: three-dimensional transesophageal echocardiography is a major advance for intraoperative clinical management of patients undergoing cardiac surgery. Anesth Analg. 2010;110(6):1574–8. 13. Hahn RT, Abraham T, Adams MS, Bruce CJ, Glas KE, Lang RM, et  al. Guidelines for performing a comprehensive transesophageal echocardiographic examination: recommendations from the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. J Am Soc Echocardiogr. 2013;26(9):921–64. 14. Lang RM, Shernan SK, Shirali GS, Mor-Avi V, editors. Comprehensive Atlas of 3D echocardiography. Philadelphia, PA: Lippincott Williams & Wilkins; 2013. 15. Nicoara A, Skubas N, Ad N, Finley A, Hahn RT, Mahmood F, et  al. Guidelines for the use of transesophageal echocardiography to assist with surgical decision-making in the operating room: a surgery-based approach. J Am Soc Echocardiogr. 2020;33(6):692–734. 16. Mercer-Rosa L, Seliem MA, Fedec A, Rome J, Rychik J, Gaynor JW. Illustration of the additional value of real-time 3-dimensional echocardiography to conventional transthoracic and transesophageal 2-dimensional echocardiography in imaging muscular ventricular septal defects: does this have any impact on individual patient treatment? J Am Soc Echocardiogr. 2006;19(12):1511–9. 17. Baker GH, Shirali G, Ringewald JM, Hsia TY, Bandisode V.  Usefulness of live three-dimensional transesophageal echocardiography in a congenital heart disease center. Am J Cardiol. 2009;103(7):1025–8. 18. Simpson JM, Miller O.  Three-dimensional echocardiography in congenital heart disease. Arch Cardiovasc Dis. 2011;104(1):45–56. 19. Vettukattil JJ. Three dimensional echocardiography in congenital heart disease. Heart. 2012;98(1):79–88. 20. Roberson DA, Cui VW. 3D echocardiography of atrial and ventricular septal defects. In: Lang RM, Shernan SK, Shirali GS, Mor-Avi V, editors. Comprehensive Atlas of 3D echocardiog-

751

raphy. Philadelphia, PA: Lippincott Williams & Wilkins; 2013. p. 287–310. 21. Shirali GS, Simpson JM.  Pediatric aspects of three-dimensional echocardiography. In: Lang RM, Shernan SK, Shirali GS, Mor-­ Avi V, editors. Comprehensive Atlas of 3D echocardiography. Philadelphia, PA: Lippincott Williams & Wilkins; 2013. p. 311–63. 22. Simpson J, Lopez L, Acar P, Friedberg MK, Khoo NS, Ko HH, et  al. Three-dimensional echocardiography in congenital heart disease: an expert consensus document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30(1):1–27. 23. Puchalski MD, Lui GK, Miller-Hance WC, Brook MM, Young LT, Bhat A, et al. Guidelines for performing a comprehensive transesophageal echocardiographic examination in children and all patients with congenital heart disease: recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019;32(2):173–215. 24. Salgo IS.  Three-dimensional echocardiographic technology. Cardiol Clin. 2007;25(2):231–9. 25. Vegas A, Meineri M. Core review: three-dimensional transesophageal echocardiography is a major advance for intraoperative clinical management of patients undergoing cardiac surgery: a core review. Anesth Analg. 2010;110(6):1548–73. 26. Salgo IS. 3D transesophageal echocardiographic technologies. In: Badano LP, Lang RM, Zamorano JL, editors. Textbook of real-­ time three dimensional echocardiography. London: Springer; 2011. p. 25–32. 27. Rabben SI. Technical principles of transthoracic three-dinensional echocardiography. In: Badano LP, Lang RM, Zamorano JL, editors. Textbook of real-time three dimensional echocardiography. London: Springer; 2011. p. 9–24. 28. Lang RM, Badano LP, Tsang W, Adams DH, Agricola E, Buck T, et  al. EAE/ASE recommendations for image acquisition and display using three-dimensional echocardiography. J Am Soc Echocardiogr. 2012;25(1):3–46. 29. Lang RM, Badano LP, Tsang W, Adams DH, Agricola E, Buck T, et  al. EAE/ASE recommendations for image acquisition and display using three-dimensional echocardiography. J Am Soc Echocardiogr. 2012;25(1):3–46. 30. Bharucha T, Roman KS, Anderson RH, Vettukattil JJ. Impact of multiplanar review of three-dimensional echocardiographic data on management of congenital heart disease. Ann Thorac Surg. 2008;86(3):875–81. 31. Bharucha T, Ho SY, Vettukattil JJ. Multiplanar review analysis of three-dimensional echocardiographic datasets gives new insights into the morphology of subaortic stenosis. Eur J Echocardiogr. 2008;9(5):614–20. 32. Jone PN, Zablah JE, Burkett DA, Schafer M, Wilson N, Morgan GJ, et al. Three-dimensional echocardiographic guidance of right heart catheterization decreases radiation exposure in atrial septal defect closures. J Am Soc Echocardiogr. 2018;31(9):1044–9. 33. Kutty S, Delaney JW, Latson LA, Danford DA.  Can we talk? Reflections on effective communication between imager and interventionalist in congenital heart disease. J Am Soc Echocardiogr. 2013;26(8):813–27. 34. Anderson RH, Loukas M.  The importance of attitudinally appropriate description of cardiac anatomy. Clin Anat. 2009;22(1):47–51. 35. Mori S, Tretter JT, Spicer DE, Bolender DL, Anderson RH. What is the real cardiac anatomy? Clin Anat. 2019;32(3):288–309. 36. Grewal J, Mankad S, Freeman WK, Click RL, Suri RM, Abel MD, et  al. Real-time three-dimensional transesophageal echocardiography in the intraoperative assessment of mitral valve disease. J Am Soc Echocardiogr. 2009;22(1):34–41.

752 37. Kronzon I, Sugeng L, Perk G, Hirsh D, Weinert L, Garcia Fernandez MA, et  al. Real-time 3-dimensional transesophageal echocardiography in the evaluation of post-operative mitral annuloplasty ring and prosthetic valve dehiscence. J Am Coll Cardiol. 2009;53(17):1543–7. 38. Mahmood F, Subramaniam B, Gorman JH, Levine RM, Gorman RC, Maslow A, et  al. Three-dimensional echocardiographic assessment of changes in mitral valve geometry after valve repair. Ann Thorac Surg. 2009;88(6):1838–44. 39. Scohy TV, Soliman OII, Lecomte PVEL, McGhie J, Kappetein AP, Hofland J, et  al. Intraoperative real time three-dimensional transesophageal echocardiographic measurement of hemodynamic, anatomic and functional changes after aortic valve replacement. Echocardiography. 2009;26(1):96–9. 40. Kelpis TG, Ninios VN, Dardas PS, Pitsis AA. Subaortic stenosis in an adult caused by two discrete membranes: a three-dimensional transesophageal echocardiographic visualization. Ann Thorac Surg. 2009;88(5):1703. 41. van Noord PT, Scohy TV, McGhie J, Bogers AJJC.  Three-­ dimensional transesophageal echocardiography in Ebstein's anomaly. Interact Cardiovasc Thorac Surg. 2010;10(5):836–7. 42. Acar P, Dulac Y, Roux D, Rougé P, Duterque D, Aggoun Y.  Comparison of transthoracic and transesophageal three-­ dimensional echocardiography for assessment of atrial septal defect diameter in children. Am J Cardiol. 2003;91(4):500–2. 43. Georgakis A, Radtke WAK, Lopez C, Fiss D, Moser C, VanDecker W, et al. Complex atrial septal defect: percutaneous repair guided by three-dimensional echocardiography. Echocardiography. 2010;27(5):590–3. 44. Price MJ, Smith MR, Rubenson DS.  Utility of on-line three-­ dimensional transesophageal echocardiography during percutaneous atrial septal defect closure. Catheter Cardiovasc Interv. 2010;75(4):570–7. 45. Saric M, Perk G, Purgess JR, Kronzon I.  Imaging atrial septal defects by real-time three-dimensional transesophageal echocardiography: step-by-step approach. J Am Soc Echocardiogr. 2010;23(11):1128–35. 46. Dall'Agata A, Cromme-Dijkhuis AH, Meijboom FJ, Spitaels SE, McGhie JS, Roelandt JR, et al. Use of three-dimensional echocardiography for analysis of outflow obstruction in congenital heart disease. Am J Cardiol. 1999;83(6):921–5. 47. Chan K-L, Liu X, Ascah KJ, Beauchesne LM, Burwash IG.  Comparison of real-time 3-dimensional echocardiography with conventional 2-dimensional echocardiography in the assessment of structural heart disease. J Am Soc Echocardiogr. 2004;17(9):976–80. 48. Takahashi K, Mackie AS, Rebeyka IM, Ross DB, Robertson M, Dyck JD, et  al. Two-dimensional versus transthoracic real-time three-dimensional echocardiography in the evaluation of the mechanisms and sites of atrioventricular valve regurgitation in a congenital heart disease population. J Am Soc Echocardiogr. 2010;23(7):726–34. 49. Simpson JM, Miller O.  Three-dimensional echocardiography in congenital heart disease. Arch Cardiovasc Dis. 2011;104(1):45–56. 50. Yagel S, Cohen SM, Rosenak D, Messing B, Lipschuetz M, Shen O, et al. Added value of three-/four-dimensional ultrasound in offline analysis and diagnosis of congenital heart disease. Ultrasound Obstet Gynecol. 2011;37(4):432–7. 51. Shirali GS.  Three-dimensional echocardiography in congenital heart disease. Echocardiography. 2012;29(2):242–8. 52. Magni G, Hijazi ZM, Pandian NG, Delabays A, Sugeng L, Laskari C, et  al. Two- and three-dimensional transesophageal echocardiography in patient selection and assessment of atrial septal defect closure by the new DAS-Angel Wings device: initial clinical experience. Circulation. 1997;96(6):1722–8.

P. C. Wong and G. R. Marx 53. Chang C-Y, Hsiung MC, Tsai SK, Wei J, Ou C-H, Chang YC, et  al. Live three-dimensional transesophageal echocardiography in an unusual case of aorto-left ventricular tunnel with a large interventricular septal aneurysm. Echocardiography. 2011;28(1):E12–5. 54. Mart CR.  Three-dimensional echocardiographic evaluation of the Fontan conduit for thrombus. Echocardiography. 2012;29(3):363–8. 55. Salcedo EE, Quaife RA, Seres T, Carroll JD.  A framework for systematic characterization of the mitral valve by real-time three-dimensional transesophageal echocardiography. J Am Soc Echocardiogr. 2009;22(10):1087–99. 56. Lang RM, Tsang W, Weinert L, Mor-Avi V, Chandra S. Valvular heart disease the value of 3-dimensional echocardiography. J Am Coll Cardiol. 2011;58(19):1933–44. 57. Vettukattil JJ, Bharucha T, Anderson RH. Defining Ebstein’s malformation using three-dimensional echocardiography. Interact Cardiovasc Thorac Surg. 2007;6(6):685–90. 58. Zhang L, Xie M, Balluz R, Ge S.  Real time three-dimensional echocardiography for evaluation of congenital heart defects: state of the art. Echocardiography. 2012;29(2):232–41. 59. Valverde I, Rawlins D, Austin C, Simpson JM. Three-dimensional echocardiography in the management of parachute mitral valve. Eur Heart J Cardiovasc Imaging. 2012;13(5):446. 60. Anwar AM, McGhie JS, Meijboom FJ, Ten Cate FJ. Double orifice mitral valve by real-time three-dimensional echocardiography. Eur J Echocardiogr. 2008;9(5):731–2. 61. Han J, He Y, Li Z, Zhang Y, Chen J, Wang L, et al. Isolated double-­ orifice mitral valve anomaly on 3-dimensional transesophageal echocardiography. J Ultrasound Med. 2009;28(11):1589–92. 62. Seliem MA, Fedec A, Szwast A, Farrell PE, Ewing S, Gruber PJ, et  al. Atrioventricular valve morphology and dynamics in congenital heart disease as imaged with real-time 3-dimensional matrix-­ array echocardiography: comparison with 2-dimensional imaging and surgical findings. J Am Soc Echocardiogr. 2007;20(7):869–76. 63. Paranon S, Acar P. Ebstein’s anomaly of the tricuspid valve: from fetus to adult: congenital heart disease. Heart. 2008;94(2):237–43. 64. Oxenius A, Attenhofer Jost CH, Prêtre R, Dave H, Bauersfeld U, Kretschmar O, et  al. Management and outcome of Ebstein’s anomaly in children. Cardiol Young 2012:1–8. 65. Negoi RI, Ispas AT, Ghiorghiu I, Filipoiu F, Negoi I, Hostiuc M, et al. Complex Ebstein's malformation: defining preoperative cardiac anatomy and function. J Card Surg. 2013;28(1):70–81. 66. Kiziltan HT, Theodoro DA, Warnes CA, O’Leary PW, Anderson BJ, Danielson GK.  Late results of bioprosthetic tricuspid valve replacement in Ebstein's anomaly. Ann Thorac Surg. 1998;66(5):1539–45. 67. Dearani JA, Danielson GK.  Surgical management of Ebstein’s anomaly in the adult. Semin Thorac Cardiovasc Surg. 2005;17(2):148–54. 68. da Silva JP, da Silva Lda F.  Ebstein's anomaly of the tricuspid valve: the cone repair. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2012;15(1):38–45. 69. Dearani JA, Said SM, O’Leary PW, Burkhart HM, Barnes RD, Cetta F. Anatomic repair of Ebstein's malformation: lessons learned with cone reconstruction. Ann Thorac Surg. 2013;95(1):220–6; discussion 6–8. 70. Sugeng L, Shernan SK, Weinert L, Shook D, Raman J, Jeevanandam V, et  al. Real-time three-dimensional transesophageal echocardiography in valve disease: comparison with surgical findings and evaluation of prosthetic valves. J Am Soc Echocardiogr. 2008;21(12):1347–54. 71. Kwak J, Andrawes M, Garvin S, D’Ambra MN. 3D transesophageal echocardiography: a review of recent literature 2007-2009. Curr Opin Anaesthesiol. 2010;23(1):80–8.

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease 72. Weitzel N, Salcedo E, Puskas F, Nasrallah F, Fullerton D, Seres T.  Using real time three-dimensional transesophageal echocardiography during Ross procedure in the operating room. Echocardiography. 2009;26(10):1278–83. 73. Brantley HP, Nekkanti R, Anderson CA, Kypson AP.  Three-­ dimensional echocardiographic features of unicuspid aortic valve stenosis correlate with surgical findings. Echocardiography. 2012;29(8):E204–7. 74. Bharucha T, Fernandes F, Slorach C, Mertens L, Friedberg MK.  Measurement of effective aortic valve area using three-­ dimensional echocardiography in children undergoing aortic balloon valvuloplasty for aortic stenosis. Echocardiography. 2012;29(4):484–91. 75. Chin C-H, Chen C-H, Lo H-S.  The correlation between three-­ dimensional vena contracta area and aortic regurgitation index in patients with aortic regurgitation. Echocardiography. 2010;27(2):161–6. 76. Khaw AV, von Bardeleben RS, Strasser C, Mohr-Kahaly S, Blankenberg S, Espinola-Klein C, et  al. Direct measurement of left ventricular outflow tract by transthoracic real-time 3D-echocardiography increases accuracy in assessment of aortic valve stenosis. Int J Cardiol. 2009;136(1):64–71. 77. Gaspar T, Adawi S, Sachner R, Asmer I, Ganaeem M, Rubinshtein R, et  al. Three-dimensional imaging of the left ventricular outflow tract: impact on aortic valve area estimation by the continuity equation. J Am Soc Echocardiogr. 2012; 78. Saitoh T, Shiota M, Izumo M, Gurudevan SV, Tolstrup K, Siegel RJ, et  al. Comparison of left ventricular outflow geometry and aortic valve area in patients with aortic stenosis by 2-­dimensional versus 3-dimensional echocardiography. Am J Cardiol. 2012;109(11):1626–31. 79. Baumgartner H, Hung J, Bermejo J, Chambers JB, Evangelista A, Griffin BP, et  al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr 2009;22(1):1–23; quiz 101–2. 80. Anwar AM, Soliman O, van den Bosch AE, McGhie JS, Geleijnse ML, ten Cate FJ, et al. Assessment of pulmonary valve and right ventricular outflow tract with real-time three-dimensional echocardiography. Int J Cardiovasc Imaging. 2007;23(2):167–75. 81. Cheng TO, Xie M-X, Wang X-F, Wang Y, Lu Q.  Real-time 3-dimensional echocardiography in assessing atrial and ventricular septal defects: an echocardiographic-surgical correlative study. Am Heart J. 2004;148(6):1091–5. 82. Chen FL, Hsiung MC, Nanda N, Hsieh KS, Chou MC. Real time three-dimensional echocardiography in assessing ventricular septal defects: an echocardiographic-surgical correlative study. Echocardiography. 2006;23(7):562–8. 83. van den Bosch AE, Ten Harkel D-J, McGhie JS, Roos-Hesselink JW, Simoons ML, Bogers AJJC, et  al. Feasibility and accuracy of real-time 3-dimensional echocardiographic assessment of ventricular septal defects. J Am Soc Echocardiogr. 2006;19(1):7–13. 84. Acar P, Abadir S, Aggoun Y. Transcatheter closure of perimembranous ventricular septal defects with Amplatzer occluder assessed by real-time three-dimensional echocardiography. Eur J Echocardiogr. 2007;8(2):110–5. 85. Huang X, Shen J, Huang Y, Zheng Z, Fei H, Hou Y, et al. En face view of atrial septal defect by two-dimensional transthoracic echocardiography: comparison to real-time three-dimensional transesophageal echocardiography. J Am Soc Echocardiogr. 2010;23(7):714–21. 86. Morgan GJ, Casey F, Craig B, Sands A. Assessing ASDs prior to device closure using 3D echocardiography. Just pretty pictures or a useful clinical tool? Eur J Echocardiogr. 2008;9(4):478–82. 87. Taniguchi M, Akagi T, Watanabe N, Okamoto Y, Nakagawa K, Kijima Y, et al. Application of real-time three-dimensional transesophageal echocardiography using a matrix array probe for trans-

753

catheter closure of atrial septal defect. J Am Soc Echocardiogr. 2009;22(10):1114–20. 88. Halpern DG, Perk G, Ruiz C, Marino N, Kronzon I. Percutaneous closure of a post-myocardial infarction ventricular septal defect guided by real-time three-dimensional echocardiography. Eur J Echocardiogr. 2009;10(4):569–71. 89. Zhu D, Tao K-Y, Liu B. Successful repair of a traumatic ventricular septal defect using an amplatzer occluder guided by three-­ dimensional transesophageal echocardiography. J Card Surg. 2010;25(6):685–9. 90. Cossor W, Cui VW, Roberson DA.  Three-dimensional echocardiographic en face views of ventricular septal defects: feasibility, accuracy, imaging protocols and reference image collection. J Am Soc Echocardiogr. 2015;28(9):1020–9. 91. Van der Velde ME, Sanders SP, Keane JF, Perry SB, Lock JE.  Transesophageal echocardiographic guidance of transcatheter ventricular septal defect closure. J Am Coll Cardiol. 1994;23(7):1660–5. 92. Holzer R, Balzer D, Cao Q-L, Lock K, Hijazi ZM, Amplatzer Muscular Ventricular Septal Defect Investigators. Device closure of muscular ventricular septal defects using the Amplatzer muscular ventricular septal defect occluder: immediate and mid-term results of a U.S. registry. J Am Coll Cardiol. 2004;43(7):1257–63. 93. Bacha EA, Cao QL, Galantowicz ME, Cheatham JP, Fleishman CE, Weinstein SW, et al. Multicenter experience with perventricular device closure of muscular ventricular septal defects. Pediatr Cardiol. 2005;26(2):169–75. 94. Butera G, Chessa M, Carminati M. Percutaneous closure of ventricular septal defects. Cardiol Young. 2007;17(3):243–53. 95. Gan C, An Q, Lin K, Tang H, Lui RC, Tao K, et al. Perventricular device closure of ventricular septal defects: six months results in 30 young children. Ann Thorac Surg. 2008;86(1):142–6. 96. Pedra CAC, Pedra SRF, Chaccur P, Jatene M, Costa RN, Hijazi ZM, et  al. Perventricular device closure of congenital muscular ventricular septal defects. Expert Rev Cardiovasc Ther. 2010;8(5):663–74. 97. Bendaly EA, Hoyer MH, Breinholt JP. Mid-term follow up of perventricular device closure of muscular ventricular septal defects. Catheter Cardiovasc Interv. 2011;78(4):577–82. 98. Geva A, McMahon CJ, Gauvreau K, Mohammed L, del Nido PJ, Geva T. Risk factors for reoperation after repair of discrete subaortic stenosis in children. J Am Coll Cardiol. 2007;50(15):1498–504. 99. Valeske K, Huber C, Mueller M, Böning A, Hijjeh N, Schranz D, et al. The dilemma of subaortic stenosis – a single center experience of 15 years with a review of the literature. Thorac Cardiovasc Surg. 2011;59(5):293–7. 100. Miyamoto K, Nakatani S, Kanzaki H, Tagusari O, Kobayashi J.  Detection of discrete subaortic stenosis by 3-­ dimensional transesophageal echocardiography. Echocardiography. 2005;22(9):783–4. 101. Maréchaux S, Juthier F, Banfi C, Vincentelli A, Prat A, Ennezat P-V. Illustration of the echocardiographic diagnosis of subaortic membrane stenosis in adults: surgical and live three-dimensional transoesophageal findings. Eur J Echocardiogr. 2011;12(1):E2. 102. Hanna R, Chen MA, Gill EA.  Cor triatriatum evaluated by real time 3D TEE. Echocardiography. 2011;28(6):E125–8. 103. Enar S, Singh P, Douglas C, Panwar SR, Manda J, Kesanolla SK, et al. Live/real time three-dimensional transthoracic echocardiographic assessment of transposition of the great arteries in the adult. Echocardiography. 2009;26(9):1095–104. 104. Balzer J, Kühl H, Rassaf T, Hoffmann R, Schauerte P, Kelm M, et  al. Real-time transesophageal three-dimensional echocardiography for guidance of percutaneous cardiac interventions: first experience. Clin Res Cardiol. 2008;97(9):565–74. 105. Gripari P, Tamborini G, Barbier P, Maltagliati AC, Galli CA, Muratori M, et  al. Real-time three-dimensional transoesopha-

754 geal echocardiography: a new intraoperative feasible and useful technology in cardiac surgery. Int J Cardiovasc Imaging. 2010;26(6):651–60. 106. Scohy TV, Ten Cate FJ, Lecomte PVEL, McGhie J, de Jong PL, Hofland J, et al. Usefulness of intraoperative real-time 3D transesophageal echocardiography in cardiac surgery. J Card Surg. 2008;23(6):784–6. 107. La Canna G, Arendar I, Maisano F, Monaco F, Collu E, Benussi S, et  al. Real-time three-dimensional transesophageal echocardiography for assessment of mitral valve functional anatomy in patients with prolapse-related regurgitation. Am J Cardiol. 2011;107(9):1365–74. 108. Charakida M, Qureshi S, Simpson JM. 3D echocardiography for planning and guidance of interventional closure of VSD.  JACC Cardiovasc Imaging. 2013;6(1):120–3. 109. Swaans MJ, Van den Branden BJL, Van der Heyden JAS, Post MC, Rensing BJWM, Eefting FD, et al. Three-dimensional transoesophageal echocardiography in a patient undergoing percutaneous mitral valve repair using the edge-to-edge clip technique. Eur J Echocardiogr. 2009;10(8):982–3. 110. Brinkman V, Kalbfleisch S, Auseon A, Pu M.  Real time three-­ dimensional transesophageal echocardiography-guided placement of left atrial appendage occlusion device. Echocardiography. 2009;26(7):855–8. 111. Perk G, Biner S, Kronzon I, Saric M, Chinitz L, Thompson K, et  al. Catheter-based left atrial appendage occlusion procedure: role of echocardiography. Eur Heart J Cardiovasc Imaging. 2012;13(2):132–8. 112. Jánosi RA, Kahlert P, Plicht B, Böse D, Wendt D, Thielmann M, et al. Guidance of percutaneous transcatheter aortic valve implantation by real-time three-dimensional transesophageal echocardiography  – a single-center experience. Minim Invasive Ther Allied Technol. 2009;18(3):142–8. 113. Horton KD, Whisenant B, Horton S.  Percutaneous closure of a mitral perivalvular leak using three dimensional real time and color flow imaging. J Am Soc Echocardiogr. 2010;23(8):903.e5–7. 114. Perk G, Kronzon I. Interventional echocardiography in structural heart disease. Curr Cardiol Rep. 2013;15(3):338. 115. Jenkins C, Bricknell K, Chan J, Hanekom L, Marwick TH.  Comparison of two- and three-dimensional echocardiography with sequential magnetic resonance imaging for evaluating left ventricular volume and ejection fraction over time in patients with healed myocardial infarction. Am J Cardiol. 2007;99(3):300–6. 116. Mor-Avi V, Jenkins C, Kühl HP, Nesser H-J, Marwick T, Franke A, et  al. Real-time 3-dimensional echocardiographic quantification of left ventricular volumes: multicenter study for validation with magnetic resonance imaging and investigation of sources of error. JACC Cardiovasc Imaging. 2008;1(4):413–23. 117. Sugeng L, Mor-Avi V, Weinert L, Niel J, Ebner C, Steringer-­ Mascherbauer R, et al. Quantitative assessment of left ventricular size and function: side-by-side comparison of real-time three-­ dimensional echocardiography and computed tomography with magnetic resonance reference. Circulation. 2006;114(7):654–61. 118. Lang RM, Addetia K, Narang A, Mor-Avi V. 3-Dimensional echocardiography: latest developments and future directions. JACC Cardiovasc Imaging. 2018;11(12):1854–78. 119. Leibundgut G, Rohner A, Grize L, Bernheim A, Kessel-Schaefer A, Bremerich J, et  al. Dynamic assessment of right ventricular volumes and function by real-time three-dimensional echocardiography: a comparison study with magnetic resonance imaging in 100 adult patients. J Am Soc Echocardiogr. 2010;23(2):116–26. 120. Sugeng L, Mor-Avi V, Weinert L, Niel J, Ebner C, Steringer-­ Mascherbauer R, et  al. Multimodality comparison of quantita-

P. C. Wong and G. R. Marx tive volumetric analysis of the right ventricle. JACC Cardiovasc Imaging. 2010;3(1):10–8. 121. Tamborini G, Marsan NA, Gripari P, Maffessanti F, Brusoni D, Muratori M, et al. Reference values for right ventricular volumes and ejection fraction with real-time three-dimensional echocardiography: evaluation in a large series of normal subjects. J Am Soc Echocardiogr. 2010;23(2):109–15. 122. Shimada YJ, Shiota M, Siegel RJ, Shiota T. Accuracy of right ventricular volumes and function determined by three-­dimensional echocardiography in comparison with magnetic resonance imaging: a meta-analysis study. J Am Soc Echocardiogr. 2010;23(9):943–53. 123. Fusini L, Tamborini G, Gripari P, Maffessanti F, Mazzanti V, Muratori M, et al. Feasibility of intraoperative three-dimensional transesophageal echocardiography in the evaluation of right ventricular volumes and function in patients undergoing cardiac surgery. J Am Soc Echocardiogr. 2011;24(8):868–77. 124. Karhausen J, Dudaryk R, Phillips-Bute B, Rivera JD, de Lange F, Milano CA, et  al. Three-dimensional transesophageal echocardiography for perioperative right ventricular assessment. Ann Thorac Surg. 2012;94(2):468–74. 125. Lang RM, Bierig M, Devereux RB, Flachskampf FA, Foster E, Pellikka PA, et al. Recommendations for chamber quantification. Eur J Echocardiogr. 2006;7(2):79–108. 126. Kapetanakis S, Kearney MT, Siva A, Gall N, Cooklin M, Monaghan MJ.  Real-time three-dimensional echocardiography: a novel technique to quantify global left ventricular mechanical dyssynchrony. Circulation. 2005;112(7):992–1000. 127. Gorcsan J III, Abraham T, Agler DA, Bax JJ, Derumeaux G, Grimm RA, et al. Echocardiography for cardiac resynchronization therapy: recommendations for performance and reporting–a report from the American Society of Echocardiography Dyssynchrony Writing Group Endorsed by the Heart Rhythm Society. J Am Soc Echocardiogr. 2008;21(3):191–213. 128. Tanaka H, Hara H, Adelstein EC, Schwartzman D, Saba S, Gorcsan J.  Comparative mechanical activation mapping of RV pacing to LBBB by 2D and 3D speckle tracking and association with response to resynchronization therapy. JACC Cardiovasc Imaging. 2010;3(5):461–71. 129. Soliman OII, Geleijnse ML, Theuns DAMJ, van Dalen BM, Vletter WB, Jordaens LJ, et al. Usefulness of left ventricular systolic dyssynchrony by real-time three-dimensional echocardiography to predict long-term response to cardiac resynchronization therapy. Am J Cardiol. 2009;103(11):1586–91. 130. Kapetanakis S, Bhan A, Murgatroyd F, Kearney MT, Gall N, Zhang Q, et  al. Real-time 3D echo in patient selection for cardiac resynchronization therapy. JACC Cardiovasc Imaging. 2011;4(1):16–26. 131. Kleijn SA, Aly MF, Knol DL, Terwee CB, Jansma EP, Abd El-Hady YA, et  al. A meta-analysis of left ventricular dyssynchrony assessment and prediction of response to cardiac resynchronization therapy by three-dimensional echocardiography. Eur Heart J Cardiovasc Imaging. 2012;13(9):763–75. 132. Wang H, Shuraih M, Ahmad M.  Real time three-dimensional echocardiography in assessment of left ventricular dyssynchrony and cardiac resynchronization therapy. Echocardiography. 2012;29(2):192–9. 133. Kahlert P, Plicht B, Schenk IM, Janosi R-A, Erbel R, Buck T. Direct assessment of size and shape of noncircular vena contracta area in functional versus organic mitral regurgitation using real-time three-dimensional echocardiography. J Am Soc Echocardiogr. 2008;21(8):912–21. 134. Pérez de Isla L, Casanova C, Almería C, Rodrigo JL, Cordeiro P, Mataix L, et  al. Which method should be the reference method to evaluate the severity of rheumatic mitral steno-

23  Three-Dimensional Transesophageal Echocardiography in Congenital Heart Disease sis? Gorlin's method versus 3D-echo. Eur J Echocardiogr. 2007;8(6):470–3. 135. Altiok E, Hamada S, van Hall S, Hanenberg M, Dohmen G, Almalla M, et al. Comparison of direct planimetry of mitral valve regurgitation orifice area by three-dimensional transesophageal echocardiography to effective regurgitant orifice area obtained by proximal flow convergence method and vena contracta area determined by color Doppler echocardiography. Am J Cardiol. 2011;107(3):452–8. 136. Tsang W, Weinert L, Sugeng L, Chandra S, Ahmad H, Spencer K, et  al. The value of three-dimensional echocardiography derived mitral valve parametric maps and the role of experience in the diagnosis of pathology. J Am Soc Echocardiogr. 2011;24(8):860–7. 137. Veronesi F, Caiani EG, Sugeng L, Fusini L, Tamborini G, Alamanni F, et  al. Effect of mitral valve repair on mitral-aortic coupling: a real-time three-dimensional transesophageal echocardiography study. J Am Soc Echocardiogr. 2012;25(5):524–31. 138. Badano LP, Muraru D. Towards an integrated echocardiographic assessment of valvular mechanics by three-dimensional volumetric imaging. J Am Soc Echocardiogr. 2012;25(5):532–4. 139. Lu X, Xie M, Tomberlin D, Klas B, Nadvoretskiy V, Ayres N, et  al. How accurately, reproducibly, and efficiently can we measure left ventricular indices using M-mode, 2-dimensional, and 3-dimensional echocardiography in children? Am Heart J. 2008;155(5):946–53. 140. Riehle TJ, Mahle WT, Parks WJ, Sallee D, Fyfe DA.  Real-time three-dimensional echocardiographic acquisition and quantification of left ventricular indices in children and young adults with congenital heart disease: comparison with magnetic resonance imaging. J Am Soc Echocardiogr. 2008;21(1):78–83. 141. Raedle-Hurst TM, Mueller M, Rentzsch A, Schaefers H-J, Herrmann E, Abdul-Khaliq H.  Assessment of left ventricular dyssynchrony and function using real-time 3-dimensional echocardiography in patients with congenital right heart disease. Am Heart J. 2009;157(4):791–8. 142. Friedberg MK, Su X, Tworetzky W, Soriano BD, Powell AJ, Marx GR. Validation of 3D echocardiographic assessment of left ventricular volumes, mass, and ejection fraction in neonates and infants with congenital heart disease: a comparison study with cardiac MRI. Circ Cardiovasc Imaging. 2010;3(6):735–42. 143. Hascoët S, Brierre G, Caudron G, Cardin C, Bongard V, Acar P.  Assessment of left ventricular volumes and function by real time three-dimensional echocardiography in a pediatric population: a TomTec versus QLAB comparison. Echocardiography. 2010;27(10):1263–73. 144. Laser KT, Bunge M, Hauffe P, Argueta JRP, Kelter-Klöpping A, Barth P, et  al. Left ventricular volumetry in healthy children and adolescents: comparison of two different real-time three-­ dimensional matrix transducers with cardiovascular magnetic resonance. Eur J Echocardiogr. 2010;11(2):138–48. 145. Iriart X, Montaudon M, Lafitte S, Chabaneix J, Réant P, Balbach T, et al. Right ventricle three-dimensional echography in corrected tetralogy of fallot: accuracy and variability. Eur J Echocardiogr. 2009;10(6):784–92. 146. Khoo NS, Young A, Occleshaw C, Cowan B, Zeng ISL, Gentles TL. Assessments of right ventricular volume and function using three-dimensional echocardiography in older children and adults with congenital heart disease: comparison with cardiac magnetic resonance imaging. J Am Soc Echocardiogr. 2009;22(11):1279–88. 147. van der Zwaan HB, Helbing WA, McGhie JS, Geleijnse ML, Luijnenburg SE, Roos-Hesselink JW, et  al. Clinical value of real-time three-dimensional echocardiography for right ventricular quantification in congenital heart disease: validation with cardiac magnetic resonance imaging. J Am Soc Echocardiogr. 2010;23(2):134–40.

755

148. Soriano BD, Hoch M, Ithuralde A, Geva T, Powell AJ, Kussman BD, et al. Matrix-array 3-dimensional echocardiographic assessment of volumes, mass, and ejection fraction in young pediatric patients with a functional single ventricle: a comparison study with cardiac magnetic resonance. Circulation. 2008;117(14):1842–8. 149. Kutty S, Graney BA, Khoo NS, Li L, Polak A, Gribben P, et al. Serial assessment of right ventricular volume and function in surgically palliated hypoplastic left heart syndrome using real-time transthoracic three-dimensional echocardiography. J Am Soc Echocardiogr. 2012;25(6):682–9. 150. Hlavacek A, Lucas J, Baker H, Chessa K, Shirali G.  Feasibility and utility of three-dimensional color flow echocardiography of the aortic arch: The “echocardiographic angiogram”. Echocardiography. 2006;23(10):860–4. 151. Pemberton J, Ge S, Thiele K, Jerosch-Herold M, Sahn DJ. Real-­ time three-dimensional color Doppler echocardiography overcomes the inaccuracies of spectral Doppler for stroke volume calculation. J Am Soc Echocardiogr. 2006;19(11):1403–10. 152. Poh KK, Levine RA, Solis J, Shen L, Flaherty M, Kang Y-J, et al. Assessing aortic valve area in aortic stenosis by continuity equation: a novel approach using real-time three-dimensional echocardiography. Eur Heart J. 2008;29(20):2526–35. 153. Lu X, Nadvoretskiy V, Klas B, Bu L, Stolpen A, Ayres NA, et al. Measurement of volumetric flow by real-time 3-dimensional doppler echocardiography in children. J Am Soc Echocardiogr. 2007;20(8):915–20. 154. Faletra FF, Pozzoli A, Agricola E, Guidotti A, Biasco L, Leo LA, et  al. Echocardiographic-fluoroscopic fusion imaging for transcatheter mitral valve repair guidance. Eur Heart J Cardiovasc Imaging. 2018;19:715–26. 155. Daeichin V, Bera D, Raghunathan S, Shabani Motlagh M, Chen Z, Chen C, et al. Acoustic characterization of a miniature matrix transducer for pediatric 3D transesophageal echocardiography. Ultrasound Med Biol. 2018;44:2143–54. 156. Rajpoot K, Grau V, Noble JA, Szmigielski C, Becher H. Multiview fusion 3-D echocardiography: improving the information and quality of real-time 3-D echocardiography. Ultrasound Med Biol. 2011;37(7):1056–72. 157. Olivieri LJ, Krieger A, Loke Y-H, Nath DS, Kim PCW, Sable CA.  Three-dimensional printing of intracardiac defects from three-dimensional echocardiographic images: feasibility and relative accuracy. J Am Soc Echocardiogr. 2015;28(4):392–7. 158. Bruckheimer E, Rotschild C, Dagan T, Amir G, Kaufman A, Gelman S, et al. Computer-generated real-time digital holography: first time use in clinical medical imaging. Eur Heart J Cardiovasc Imaging. 2016;17(8):845–9. 159. Vukicevic M, Mosadegh B, Min JK, Little SH.  Cardiac 3D printing and its future directions. JACC Cardiovasc Imaging. 2017;10(2):171–84. 160. Lasso A, Nam HH, Dinh PV, Pinter C, Fillion-Robin JC, Pieper S, et  al. Interaction with volume-rendered three-dimensional echocardiographic images in virtual reality. J Am Soc Echocardiogr. 2018;31(10):1158–60. 161. Ballocca F, Meier LM, Ladha K, Qua Hiansen J, Horlick EM, Meineri M. Validation of quantitative 3-dimensional transesophageal echocardiography mitral valve analysis using stereoscopic display. J Cardiothorac Vasc Anesth. 2019;33(3):732–41. 162. Dumont KA, Kvitting JPE, Karlsen JS, Remme EW, Hausken J, Lundblad R, et al. Validation of a holographic display for quantification of mitral annular dynamics by three-dimensional echocardiography. J Am Soc Echocardiogr 2019;32(2):303–16 e4. 163. Lu JC, Ensing GJ, Ohye RG, Romano JC, Sassalos P, Owens ST, et  al. Stereoscopic three-dimensional visualization for congenital heart surgery planning: surgeons’ perspectives. J Am Soc Echocardiogr. 2020;33(6):775–7.

Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

24

Vivian W. Cui and David A. Roberson

Abbreviations 2D Two-dimensional 2DE Two-dimensional echocardiography 3D color mode Color Doppler flow mapping using 3D echocardiography 3D full volume ECG gaited multi-beat large volume 3DE 3D TEE Three-dimensional transesophageal echocardiography 3D Zoom Live wide sector 3D echocardiography 3D Three-dimensional 3DE Three-dimensional echocardiography A Anterior AoV Aortic valve ASD Atrial septal defect CHD Congenital heart disease ECG Electrocardiogram Echo Echocardiographic EP Electrophysiology I Inferior L Left Live 3D Live narrow sector 3D echocardiography LV Left ventricle LVOT Left ventricle outflow tract MPR Multi-planar reconstruction P Posterior R Right RV Right ventricle RVOT Right ventricle outflow tract S Superior

Electronic Supplementary Material The online version of this chapter (https://doi.org/10.1007/978-­3-­030-­57193-­1_24) contains supplementary material, which is available to authorized users. V. W. Cui · D. A. Roberson (*) Advocate Children’s Heart Institute, Chicago, Illinois, USA e-mail: [email protected]

TEE VSD X-Plane

Transesophageal echocardiography Ventricular septal defect Live biplane 2D echocardiography

Key Learning Objectives • Become familiar with the four 3D TEE acquisition modalities • Learn basic principles of 3D TEE acquisition • Learn the 3D TEE display modalities • Know the guidelines-based recommended clinical applications of 3D TEE  in pediatric patients and all patients (adult and pediatric) with congenital heart disease

Introduction Since the time that three-dimensional transesophageal echocardiography (3D TEE) became widely available in 2008, its adoption and application as an essential imaging modality in adult cardiology has been substantial, particularly for aortic and mitral valve interventions [1–12]. Notwithstanding this progress, the use of 3D TEE in patients with congenital heart disease (CHD) has developed at a considerably slower rate. This may be due in part to the limitation of the use of 3D TEE for those patients with a body weight greater than 20 kg due to the lack of suitable size probes for smaller children. However, there are other factors, including (a) limited information on protocols for usage, (b) lack of widespread communication about the best practices for image acquisition and optimization, and (c) limited demonstration in the literature of the clinical utility of 3D TEE for CHD evaluation. All of these have contributed to the relatively slow proliferation of 3D TEE as a commonly applied, useful and valuable clinical imaging tool for those with CHD. In this chapter,

© Springer Nature Switzerland AG 2021 P. C. Wong, W. C. Miller-Hance (eds.), Transesophageal Echocardiography for Pediatric and Congenital Heart Disease, https://doi.org/10.1007/978-3-030-57193-1_24

757

758

V. W. Cui and D. A. Roberson

cardiac pathology specimen [13–24]. Valve leaflets, septal structures and the real-time depiction of spatial relationships provide clearer anatomic definition and better understanding of the actual cardiac anatomy as compared to two-­ dimensional echocardiography (2DE) [25–27]. 3DE has become important in the management of CHD for pre-­ surgical planning, guidance of catheter intervention and functional assessment of the heart.

Note the 3D orientation icon in the figures: Y

• • • • • •

A = anterior I = inferior L = left P = posterior R = right S = superior

Z

3D TEE Imaging Techniques X

Fig. 24.1  Three dimensional orientation icon displayed in the figures. Abbreviations: A anterior, I inferior, L left, P posterior, R right, S Superior

we present images from various clinical cases that in our opinion clearly demonstrate the benefits of 3D TEE in CHD.  Images from both simple and complex congenital cardiac anomalies are presented. Representative examples of applications in the interventional catheterization laboratory are provided. Selected examples of surgical repairs and palliations are displayed. In addition, images useful during the treatment of patients undergoing electrophysiologic procedures are illustrated. We also offer suggestions of which methods to use in order to optimize 3D TEE capabilities. These include the acquisition modality that might best be applied for a particular structure of interest and other methods to optimize image display. Our entire case collection for 3D TEE and the examples presented in this chapter are based upon our experience using the Philips iE33 and EPIQ echocardiographic systems and X7–2t 3D TEE transducer (Philips Medical Systems, Andover, Massachusetts). Nonetheless we believe the principles embodied in this chapter will have widespread applicability to all forms of 3D TEE evaluation of CHD, irrespective of ultrasound platform or manufacturer. The reader is also referred to Chap. 23 for an overview of general concepts regarding three-dimensional (3D) imaging. A brief illustration of the 3D orientation nomenclature is given in Fig. 24.1.

Defining Three-Dimensional Cardiac Anatomy The ability of three-dimensional echocardiography (3DE) to demonstrate surfaces, volumes and spatial relationships allows the echocardiographer to acquire and display views of the heart and great vessels that are analogous to viewing a

3DE is complementary to 2DE for assessment of CHD. Clear visualization by 2DE is required in order to obtain a high quality 3DE image. 3D TEE is incorporated selectively within the two dimensional (2D) examination work flow using the appropriate acquisition modes which include live biplane 2DE (X-plane), live real time narrow sector 3DE (Live 3D), live real time wide sector 3DE (3D Zoom), and ECG-gated multi-beat large volume 3DE (3D full volume). Color Doppler flow mapping is available in all 3D modalities (3D color mode). At our institution, we have adopted a 20  kg bodyweight as the lower limit of patient size suitable to safely perform 3D TEE using currently available transducers. Key principles include using the best 3DE modalities for the cardiac structure of interest, and being mindful of spatial and temporal resolution limitations. The angle of insonation should be orthogonal to the relevant structure in order to develop en face views. The 3DE region of interest sample volume size should be adjusted to be small enough to optimize temporal and spatial resolution, and large enough to include clinically relevant structures and anatomic landmarks. The  view aspect and gain settings should be optimized  to enhance 3D depth perception. Electrocardiogram (ECG) gated multi-beat acquisition of large data sets improves temporal resolution, but is prone to stitch artifact – a situation where the stitched together 3D reconstruction segments are not temporally aligned. This artifact can be mitigated by suspending respiration and electrocautery, avoiding transducer movement, using a high rate averaging image algorithm, and decreasing acquisition sample volume size. The addition of 3D color mode may cause substantially reduced volume rates in some cases.

Image Display Presentation format of images include volume rendered 3D images for morphologic assessment, multiplanar reconstruction (MPR) format consisting of multiple simultaneous 2D plane images plus a 3D rendered view, and surface- rendered cast models of the left ventricle (LV) and right ventricle (RV) used to measure ventricular volume and function. En face

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

views of septa and atrioventricular (AV) valves should retain important landmarks. An anatomic approach to image display consistent with cardiac magnetic resonance and computed tomography imaging is most often used. Alternatively, a surgical view may be used to show the anatomy as the surgeon would visualize it.

Guidelines-Based Recommendations An important guidelines article related to 3DE in CHD was published in 2017 [28]. In addition, a recently published guidelines article related to transesophageal echocardiography (TEE) in CHD includes a number of recommendations regarding the application of 3DE for specific cardiac abnormalities in pediatric patients and all patients with CHD [29]. According to these two guidelines, 3DE is recommended for the assessment of valvar lesions, septal defects and complex abnormalities of cardiac connections. It is also highly recommended for the evaluation of the  atrial septum, ventricular septum, tricuspid valve, mitral valve, left ventricular outflow tract (LVOT), aortic valve (AoV), atrioventricular septal defect, congenitally corrected transposition and complex transposition. In terms of cardiac valve imaging, 3D TEE is recommended for visualization of atrioventricular valve leaf-

759

lets, papillary muscles and chordae and valve orifice area; it is specifically recommended for the visualization of semilunar valve leaflet morphology, annulus size, root size and effective orifice area. This modality is also used to assess location, size, shape, and number of regurgitant jets. Tables 24.1, 24.2, and 24.3 provide a summary of specific recommendations for 3D TEE, especially for CHD evaluation. Three-dimensional TEE is also recommended to assist interventional closure of selected atrial septal defects (ASDs) and ventricular septal defects (VSDs), particularly multiple, irregularly shaped, or residual defects. During electrophysiology (EP) procedures, 3D TEE is recommended for visualization of catheter delivery systems and devices. A two person team consisting of a skilled sonographer and imaging physician is advisable to perform 3D TEE in the time-­ constrained settings of the interventional catheterization and EP laboratories, and also in the operating room.

I maging During Interventional Cath Procedures The use of 3D TEE as a complementary imaging modality to 2D TEE during interventional catheterization allows one to obtain useful and unique views which define the important

Table 24.1  Use of 3D TEE in congenital lesions with normal cardiac connections Region of interest Atrial septum

Tricuspid valve

Information acquired (I) Comment (C) I: Size/number/shape/location of defects C: High value for multiple defects, multiple device deployment, residual leaks, spiral defects

I: Leaflet morphology, chordal support, regurgitant jets C: Mechanism/severity of regurgitation refined Mitral valve I: Leaflet morphology, chordal support, regurgitant jets C: Mechanism/severity of regurgitation refined Ventricular septum I: Size/number/shape/location of defects C: High value for multiple defects, unusually located defects or consideration of interventional closure Left ventricular outflow I: Morphology of subaortic obstruction and aortic valve tract C: Clarify mechanism of obstruction and/or regurgitation Aortic valve I: Measurement of aortic valve, morphology of leaflets, mechanism of aortic regurgitation C: Imaging of aortic valve leaflets Aortic arch I: Morphology and sizing of aortic arch C: Imaging may be difficult due to probe size, acoustic access Right ventricular outflow I: RVOT morphology, visualization of site of RVOT obstruction tract C: Questionable benefit over 2DE Pulmonary valve I: PV morphology and function C: May be able to visualize PV morphology better than 2DE Branch pulmonary arteries

Strength of recommendation HIGH for complex or residual defects MODERATE for single central defects LOW for PFO HIGH HIGH HIGH for more complex defects LOW for other defects HIGH HIGH

LOW/MOD LOW/MODERATE LOW Not routinely used

Abbreviations: 2DE two-dimensional echocardiography, PV pulmonary valve, RVOT right ventricular outflow tract From Simpson et al. [28]; used with permission by Elsevier

760

V. W. Cui and D. A. Roberson

Table 24.2  Use of 3D TEE for the heart with abnormal cardiac connections Information acquired (I) Comment (C) I: Size of atrial and ventricular components of the defect, leaflet morphology and chordal support, delineation of regurgitant jets, valvar and ventricular size in unbalanced defects C: Enhances measurement of valve size, chordal support and relative size of AV valves and ventricles Discordant atrioventricular I: TV and MV morphology and function, location and size of associated VSDs, left and connections right ventricular outflow tract C: Improves assessment of feasibility of Senning/Rastelli approach. Improves localization of VSDs Complex transposition of I: MV and TV morphology and size, location of associated VSDs, anatomy of left or the great arteries right ventricular outflow tract obstruction C: Assess suitability for procedures such as Rastelli, Nikaidoh and arterial switch operations Tetralogy of Fallot I: VSD size/location and RVOT anatomy C: Indicated where specific concerns, e.g. VSD position or RVOT anatomy Common arterial trunk I: Truncal valve morphology/regurgitation C: may assist delineation of truncal valve morphology/regurgitation Double outlet right ventricle I: Relationship of AV valves VSD size and location, relative position of great arteries C: High value for guiding appropriate type of repair Systemic venous abnormalities Abnormal pulmonary venous drainage D-transposition of the great arteries Region of interest Atrioventricular septal defect

Strength of recommendation HIGH

HIGH

HIGH

LOW HIGH for truncal valve HIGH Not routinely used Not routinely used Not routinely used

Abbreviations: AV atrioventricular, MV mitral valve, RVOT right ventricular outflow tract TV, tricuspid valve, VSD ventricular septal defect From Simpson et al. [28]; used with permission by Elsevier Table 24.3  Clinical applications for which 3D TEE has been used successfully 3D TEE in patients with CHD is recommended for the following: •  ASD device closure guidance •  VSD device closure guidance •  Visualization of catheters, delivery systems and devices •  Measurements of defects visualized in en face views •  Analysis of the anatomy and function of atrioventricular valves •  Visualization of the aortic valve and left ventricular outflow tract 3D TEE in patients with CHD has been used successfully for the following: •  Fontan fenestration device closure •  Ruptured sinus of Valsalva aneurysm device closure •  Coronary artery fistula device closure •  Prosthetic valve paravalvar leak device closure •  Atrial switch baffle leak device closure •  Atrial septum transseptal catheterization during various procedures • Biventricular pacemaker synchrony assessment and lead placement guidance

tor), 3D Zoom, and X-plane, are most often used as they are only rarely need cropping.

Assessment of Surgical Interventions The outstanding advances in congenital cardiac surgery (particularly for neonates and infants) that have been achieved over the years have resulted in survival into adulthood for most patients with CHD. The plethora of surgical procedures and their myriad variations available today can sometimes be challenging to the echocardiographer. For both pre-bypass and post-bypass intraoperative assessment, 3D TEE can provide unique detailed views as well as information complementary to 2DE findings, and these are clinically useful as well as educational.

Abbreviations: ASD atrial septal defect, VSD ventricular septal defect From Simpson et al. [28]; used with permission by Elsevier

defects, surrounding structures and interventional hardware (Table 24.3). Live methods are now available, and they are rapid and easy to use. It is important to become familiar with all of the important controls on the specific echocardiography platform that is being used; this enables the practitioner to apply these techniques promptly, so as not to prolong the procedure. The live methods, including Live 3D (narrow sec-

I maging Related to Electrophysiology Procedures Successful treatment of the majority of patients with CHD, and their resultant prolonged survival, has resulted in a sizeable population of individuals who develop arrhythmias that might require cardioversion, a cardiac defibrillator, and/or pacemaker implantation.

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

Case Examples Congenitally Corrected Transposition (L-Transposition) of the Great Arteries Figure 24.2 was obtained from a patient with congenitally corrected transposition, illustrating the four cardiac chambers and valves, imaged from the midesophageal four chamber (ME 4-Ch) view. These images were obtained using a 3D full volume acquisition mode. This 3DE modality is most useful for obtaining the entire cardiac echocardiographic (echo) volume in one cine loop. Once acquired, this echo volume can be cropped and rotated from any direction in order to display the relevant anatomy. As this 3DE modality can be prone to stitch artifact (refer to Chap. 23), important techniques to optimize the image include breath holding, maximizing 3DE volume rate, using MPR mode and editing out cine loops in which artifact is present.

a

Fig. 24.2  3D full volume acquisitions of congenitally corrected transposition (L-TGA). (a) Midesophageal four-chamber view. (b) Four valve en face view. AoV aortic valve, LA left atrium, LV left ventricle,

761

Figure  24.2a is cropped with one touch by using the auto crop button, which removes the anterior 50% of the echocardiographic volume. Figure 24.2b is not cropped at all, but is merely a full volume acquisition with the superior plane tilted towards the viewer. Relatively low gain and compression settings, as well as slight angulation or tilting of the 3D cardiac image, should be used in order to enhance the depth shading. Figure 24.3 is a deep transgastric RV outflow tract (DTG RVOT) view obtained from the same patient with inverted ventricles shown in Fig.  24.2 depicting the three leaflets of the tricuspid valve in the morphologic right ventricle. This image was obtained using the Live 3D mode, which maximizes volume rate at the expense of requiring a smaller 3DE sample volume. This modality has an additional advantage of minimizing stitch artifact and is therefore quite useful for patients with faster heart rates or for viewing rapidly moving structures such as semilunar valves. Especially when learning 3DE, as well as in cases in which

b

MV mitral valve, PV pulmonary valve, RA right atrium, RV right ventricle, TV tricuspid valve

762

V. W. Cui and D. A. Roberson

imaging time is limited, such as during surgery and interventional catheterization procedures, we have found it most effective to have two echocardiographers involved: one manipulates the transducer while the other operates the controls on the echocardiography machine. Both roles must be learned and coordinated by both operators in order to achieve the full potential of 3D TEE.

Cor Triatriatum

Fig. 24.3  Live 3D deep transgastric right ventricular outflow tract view obtained in the same patient presented in Fig. 24.2 with congenitally corrected transposition (L-TGA). Note the en face view of the tricuspid valve in the left-sided, posteriorly positioned right ventricle (RV). A anterior leaflet of tricuspid valve, LV left ventricle, P posterior leaflet of tricuspid valve, SL septal leaflet of the tricuspid valve, VS ventricular septum

a

Fig. 24.4  A case of cor triatriatum, dextrocardia and multiple ventricular septal defects (see as yellow arrows) as displayed from the midesophageal four-chamber view, using 3D full volume acquisition. (a) The cor triatriatum membrane (cor t; green arrow) divides the left

Images from a patient with dextrocardia, multiple ventricular septal defects (VSDs) and cor triatriatum undergoing surgical resection of the obstructive membrane are shown in Fig. 24.4. Note the clearly defined anatomic details including the depth, orifices and surfaces of the cardiac structures in this complex lesion. Also note that, as in the prior case example, we applied 3D full volume to obtain the entire cardiac 3D volume as a first step as illustrated in Fig.  24.4a and Video 24.1. Subsequently we used Live 3D to focus on specific details in real time as seen in Fig. 24.4b. The actual obstructive orifice of the cor triatriatum membrane is seen in this figure as if one were viewing a pathology specimen from above. In Fig. 24.5a we applied X-plane color Doppler flow mapping consisting of live X-plane biplane echocardiography, analogous to biplane angiography, which provides simultaneous live imag-

b

atrium into proximal (LAp) and distal (LAd) chambers. (b) The image has been cropped from above and tilted forward to demonstrate the cor triatriatum orifice. LV left ventricle, RA right atrium, RV right ventricle

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

763

b

Fig. 24.5  Color Doppler flow analysis is presented from the same case shown in Fig. 24.4. (a) X-plane color Doppler display of the turbulent flow through the cor triatriatum orifice as seen from orthogonal views

(frontal and lateral). The cor triatriatum membrane is indicated by the arrow. (b) 3D color Doppler flow map as seen from a posterior view is shown. LAp proximal chamber, LAd distal chamber, LV left ventricle

ing of the frontal and lateral planes. Using any of the 3DE modalities, one can rotate the cardiac images 180° in order to provide unique views of the heart from its posterior (contralateral) aspect. This is depicted in the 3D color Doppler flow map in Fig. 24.5b and Video 24.2, demonstrating flow through the obstructive membrane orifice in this case.

tissue display), along with lower gain settings, are essential to provide the optimal 3D effect. Also, the anatomic details of leaflet thickening, raphe thickness and orientation, and the valve orifice shape, size and location are viewed in greater detail. We consider Live 3D acquired from the midesophageal aortic valve short axis (ME AoV SAX) view to be the best currently available modality to obtain these anatomic details of the aortic valve.

Bicuspid Aortic Valve Live 3D images of the two most common types of bicuspid aortic valve, namely left–right commissural fusion and right-­ non coronary commissure fusion, are presented in Fig. 24.6. The valve leaflet surface and depth can be clearly displayed by 3D imaging (Fig. 24.6, Videos 24.3 and 24.4). The blue depth shading provided by using the H tissue algorithm (3D

Parachute Mitral Valve Parachute mitral valve deformities from two patients are presented on Figs. 24.7 and 24.8 respectively. Figure. 24.7a is a 3D Zoom acquisition of the mitral valve in which the hypoplastic mitral valve orifice is viewed from the left

764

V. W. Cui and D. A. Roberson

a

b

c

d

Fig. 24.6  Live 3D midesophageal aortic valve short axis acquisitions of the two most common variants of the bicuspid aortic valve (AoV). Images in the top row are from a patient with left and right leaflet fusion (Fused L-R). The view during systole is labeled (a) and the view during

diastole is labeled (b). Images in the bottom row are from a patient with right and non-coronary leaflet fusion (Fused R-N). The view during systole is labeled (c) and the view during diastole is labeled (d)

atrium. 3D Zoom mode is our preferred method to visualize the mitral valve because it is live, rapid, and very easy to perform. It has the drawback of having a slow volume rate, although this problem can be mitigated by using the high volume rate (HVR) imaging modality. It provides for increased volume rate at the expense of slightly decreased resolution. Figure 24.7b and Video 24.5 are from a frontal cropped 3D full volume of the hypoplastic stenotic para-

chute mitral valve, obtained from the ME 4-Ch view. Live 3D was used to acquire Fig.  24.8, which demonstrates a parachute mitral valve in a patient with double inlet left ventricle. Note from these three examples that after the image has been acquired and appropriately cropped and displayed, it is not always easy to determine which acquisition modality—3D Zoom vs. 3D full volume vs. Live 3D—was employed.

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

Fig. 24.7  Views of a parachute mitral valve. (a) 3D zoom mode acquisition viewed from the left atrium shows the hypoplastic mitral valve (MV) orifice (yellow arrow). (b) 3D full volume midesophageal four-­

765

b

chamber view displays the hypoplastic and doming mitral valve (yellow arrow). LA left atrium, LAA left atrial appendage, LV left ventricle, RA right atrium, RV right ventricle

Ventricular Septal Defects

Fig. 24.8  Live 3D acquisition in a patient with double inlet left ventricle and parachute left sided atrioventricular valve obtained from the midesophageal four-chamber view. The very small mitral orifice (*), single small papillary muscle (PM) and parachute or funnel shape deformity of the mitral valve are apparent. LA left atrium, LV left ventricle

The advantages of 3D TEE to demonstrate the anatomy of VSDs are apparent in Figs. 24.9 and 24.10. En face views of the ventricular septum from either the right or left ventricular aspect demonstrate the size, shape, location and orientation of the defect as well as its relationship to surrounding structures. An interesting aspect of VSD imaging we have noted is that the majority of defects we have imaged have the longest dimension in the Z plane (anterior-posterior), a plane unique to 3DE. Therefore, the actual largest dimension and overall size of the VSD may be better depicted using 3D versus 2D echocardiography in many cases. Figure 24.9 and Video 24.6 represent Live 3D color. Doppler flow maps of a muscular VSD are shown from a slightly oblique ME 4-Ch view (Fig. 24.9a) and a midesophageal long axis (ME LAX) view (Fig. 24.9b). The images in Fig.  24.10 are cropped 3D full volume acquisitions of a perimembranous VSD.  The right ventricular  (Fig. 24.10a) and left ventricular  (Figure 24.10c)  en face views are obtained by cropping from the respective right or left sides and rotating the images to face the viewer. Obtaining en face views of septal structures is one of the basic 3DE skills

766

a

V. W. Cui and D. A. Roberson

b

Fig. 24.9  Live 3D color Doppler flow mapping images of a muscular ventricular septal defect (VSD). (a) Midesophageal four-chamber view with left oblique rotation showing the VSD. (b) Demonstration of the

defect using a midesophageal long axis view with color Doppler flow mapping. LA left atrium, LV left ventricle, RA right atrium, RV right ventricle, RVOT right ventricular outflow tract

that must be mastered in the assessment of congenital heart defects. The center image of Fig. 24.10b and Video 24.7. are the frontal cropped full volume images obtained from the ME 4-Ch view, as previously discussed.

are presented in Fig. 24.11. By cropping the image from the superior direction and tilting the cardiac base toward the viewer, the atrioventricular (AV) valves are seen from the atrial view (Fig.  24.11a). By cropping from the inferior direction and tilting the apex toward the viewer, the AV valves are seen from the ventricular view (Fig.  24.11b). Finally, another example of a frontal cropped ME 4-Ch view is demonstrated (Fig. 24.11c). This view functions as a good home base view from which to proceed with more involved 3D cropping and views.

Double Inlet Left Ventricle Images from a patient with double inlet left ventricle, acquired from the ME 4-Ch view using 3D full volume TEE

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

b

Fig. 24.10  A perimembranous ventricular septal defect (VSD; asterisk) as seen from a midesophageal four-chamber view using 3D full volume acquisition. See Video 24.7. (a) Right-sided en face view. (b)

767

c

Four-chamber view with slight rightward rotation. (c) Left-sided en face view. AoV aortic valve, LA left atrium, LV left ventricle, RA right atrium, RV right ventricle, VS ventricular septum

a

b Fig. 24.11  3D full volume acquisition from a midesophageal four-­ chamber view in a patient with double inlet left ventricle. (a) View of both atrioventricular valves from the atrium. The right sided atrioventricular valve is labeled (1) and the left sided valve is labeled (2). (b)

c

View of both atrioventricular valves from the ventricular aspect. (c) The midesophageal four-chamber view is depicted (although in this case, there are only three chambers). LA left atrium, LV left ventricle, RA right atrium

768

Atrial Septal Defects Analogous to 3D imaging of VSDs, imaging of ASDs using 3D TEE employs en face and long axis views. In Fig. 24.12a, a 3D Zoom en face view of a large inferior sinus venosus ASD is shown from the right atrial aspect. A superior type sinus venosus ASD with partial anomalous pulmonary veins is presented in Fig. 24.12b. This image was obtained from a modified midesophageal bicaval (ME Bicaval) view (probe has been withdrawn), using a cropped 3D full volume image.

 pplications During Interventional Cardiac A Catheterization The closure of secundum ASDs and muscular VSDs using interventional catheterization techniques has become com-

a

Fig. 24.12  Sinus venosus atrial septal defects. (a) A 3D zoom acquisition view of inferior sinus venosus atrial septal defect (ASD) is shown. (b) 3D full volume acquisition from a modified midesophageal bicaval view of a superior sinus venosus ASD with anomalous drainage of the

V. W. Cui and D. A. Roberson

monplace at CHD treatment centers. The en face views of the septal anatomy and surrounding structures, as well as the ability of 3D TEE to visualize interventional procedure hardware rapidly and in 3D detail, are quite helpful to guide the performance of these procedures. Currently, our interventional cardiology colleagues expect that we perform this analysis on a routine basis during these procedures. The 3D TEE acquisition modalities most useful during these tasks include the 3D Zoom and Live 3D, both of which are Live 3D modalities.

 ranscatheter Closure of Secundum Atrial T Septal Defect The en face views of the atrial septum acquired at the midesophageal level using 3D Zoom mode are most useful during transcatheter ASD device closure. In a single view, the

b

right pulmonary veins (RPV) into the superior vena cava (SVC). CS coronary sinus, LA left atrium, IVC inferior vena cava, RA right atrium, RPA right pulmonary artery

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

dimensions, location, shape, rims, number of orifices and important surrounding structures are demonstrated. This is illustrated in Fig.  24.13. This view is also very useful to monitor wire, catheter and device manipulations. The common ASD rim deficiencies that can make device deployment challenging or impossible are presented in Fig.  24.14.

a

Fig. 24.13  Anatomic landmarks obtained from views in the midesophagus using 3D zoom mode during secundum atrial septal defect (ASD) device closure. (a) Right atrial (RA) en face view. (b) Left atrial (LA) en

769

Figure  24.14a and b display the usual 3D Zoom en face views from a right atrial perspective. Figure  24.14c shows another very useful 3D TEE view used during transcatheter ASD device closure. This is a Live 3D deep transgastric atrial septal (DTG Atr Sept) view that provides the best views possible of the inferior rim of the ASD. Multiple ori-

b

face view. A catheter (c) passes through the ASD. Ao aorta, IVC inferior vena cava, SVC superior vena cava

770

V. W. Cui and D. A. Roberson

a

b

c

Fig. 24.14  Common secundum atrial septal defect (ASD) rim deficiencies are presented. In each figure the deficient rim is indicated by the arrow and the ASD is marked by an asterisk (*). (a) Aortic rim deficiency as seen from a midesophageal right atrial (RA) en face 3D zoom view. (b) Inferior rim deficiency as seen from a midesophageal RA en

face 3D zoom view. (c) Superior rim deficiency as seen from a deep transgastric atrial septal live 3D view. The blue arrow indicates the inferior rim of the defect, typically optimally seen in this view. Ao aorta, IVC inferior vena cava, LA left atrium, RPA right pulmonary artery, SVC superior vena cava

fice secundum ASDs are not rare, therefore a collection of these is presented in Fig.  24.15 and also in  Video 24.8. Lastly, views of the three commonly used contemporary ASD closure devices, namely the Amplatzer™, Helex® and GSO GORE® Cardioform Septal Occluder (GSO)  devices are presented in Fig. 24.16.

 ranscatheter Closure of Muscular Ventricular T Septal Defect The use of 3D TEE during device closure of muscular VSDs is illustrated in Figs. 24.17 and 24.18, Video 24.9. All images in the two figures are obtained from ME 4-Ch full volume acqui-

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

b

c

d

771

Fig. 24.15  Examples of four patients with multiple orifice secundum atrial septal defect (ASD). All images were obtained from the midesophageal level using 3D zoom mode. (a) A thin vertical band (B) of septum primum divides the ASD (arrows) into two orifices (large anterior and small posterior orifices). (b) Similar findings from a different

patient. (c) Two small defects are demonstrated (identified as 1 and 2). (d) Two small defects (arrows) and a larger defect are present. Ao aorta, C catheter, IVC inferior vena cava,  RA, right atrium, S1 septum primum, SVC superior vena cava

sitions with side cropping to show en face views or frontal cropping to demonstrate the VSD and the device. Figure 24.17 is from a patient with a congenital VSD and Fig. 24.18 is from a case with post-myocardial infarction VSD.

Surgery for Left Sided Obstructive Lesions Representative 3D images of several different surgical procedures applied in the management of left sided obstructive

772

V. W. Cui and D. A. Roberson

™

®

lesions are presented in Figs.  24.19, 24.20, and 24.21. In Fig. 24.19 and Video 24.10, dehiscence of aortic valve leaflet augmentation material is demonstrated in a midesophageal aortic valve long axis (ME AoV LAX) 3D full volume view with frontal cropping. A Konno procedure with bioprosthetic valve is shown using Live 3D mode acquisitions from the ME AoV LAX (Fig. 24.20a, Video 24.11) and ME AoV SAX (Fig. 24.20b, Video 24.12) views. Figure 24.21 is a DTG RVOT Live 3D view of a Damus-Kaye-Stansel procedure.

Surgery for Atrioventricular Valves

®

Fig. 24.16  Views of the commonly used transcatheter atrial septal defect closure devices. (top) Amplatzer septal occluder, (middle) Helex septal occluder, (bottom) Gore septal occluder

En face views of the AV valves are most often obtained using 3D Zoom mode. The valves may be viewed from either the atrial or ventricular aspect. Despite the slow volume rate of this modality, fine anatomic details can usually be demonstrated. The newly developed high volume rate (HVR) software adjustment mitigates the slow volume rate

a

b

c

d

Fig. 24.17  3D full volume acquisitions showing a muscular ventricular septal defect (VSD) before and after transcatheter device closure. The images were obtained from the midesophageal four-chamber view. (a) Right en face view of the VSD (shown by arrow). (b) Left en face

view of the VSD (arrow). (c) The delivery catheter is through the VSD. (d) The closure device is in place. LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

773

a

b

c

Fig. 24.18  Live 3D views of a ventricular septal defect (VSD) caused by a myocardial infarction, located in the apical muscular ventricular septum. Images were obtained from the midesophageal four-chamber view during device closure. (a) Left sided en face view of the VSD

a

Fig. 24.19  Live 3D acquisition in midesophageal aortic valve long axis view displaying dehiscence of a bicuspid aortic valve leaflet augmentation repair in a patient with endocarditis. (a) The leaflet augmentation flap of Gore-Tex (yellow arrow) is within the aorta during systole.

(arrow). (b) Left side of the device deployed in the left ventricle, shown from a frontal view. The delivery catheter is labeled (C). (c) The device is in good position. LA left atrium, LV left ventricle, RV right ventricle, VS ventricular septum

b

The aortic valve is noted by a blue arrow. (b) The flap is within the left ventricle during diastole. Ao aorta, AoV aortic valve, LA left atrium, LVOT left ventricular outflow tract

774

V. W. Cui and D. A. Roberson

a

Fig. 24.20  Midesophageal aortic valve long axis (a) and short axis (b) views. 3D full volume acquisitions of a Konno procedure are displayed. The ventricular septal defect  (VSD) patch and bioprosthetic aortic Fig. 24.21  Demonstration of the Damus-Kaye-Stansel (DKS) procedure (asterisk) performed in a patient with univentricular heart, subaortic stenosis and D-malposed aorta. This is a deep transgastric right ventricular outflow tract live 3D acquisition. Ao aorta, PA pulmonary artery, RV right ventricle

b

valve are demonstrated. Ao aorta, AoV aortic valve, LVOT left ventricular outflow tract, RV right ventricle, RVOT right ventricular outflow tract

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

to a significant degree. Figure 24.22 displays dehiscence of a tricuspid valve ring repair in a patient with Ebstein’s anomaly.

Right Ventricular to Pulmonary Artery Conduit A right ventricular to pulmonary artery conduit is sometimes difficult to image clearly by TEE due to its anterior and superior position relative to the esophagus. In Fig. 24.23, Live 3D anatomic and Live 3D color flow Doppler mapping views of

a

775

an RV to PA conduit are demonstrated from upper esophageal pulmonary artery (UE PA) view.

Atrial Switch Procedures The atrial switch procedures (Mustard and Senning), formerly first line surgical therapies for D-transposition of the great arteries, are compatible with long term survival, although a number of complications can occur over time including baffle obstruction, baffle leak and arrhythmias.

b

Fig. 24.22  3D zoom mode views of a tricuspid valve ring dehiscence (arrow) after repair of Ebstein’s anomaly as viewed from the right atrium (RA, a) and the right ventricle (RV, b). The tricuspid valve orifice is marked with an asterisk (*)

776 Fig. 24.23  Live 3D anatomic (a) and color Doppler flow mapping (b) views of a Rastelli conduit imaged from the upper esophageal pulmonary artery view. C conduit LPA left pulmonary artery, RPA right pulmonary artery

a

V. W. Cui and D. A. Roberson

a

b

b

Fig. 24.24  A midesophageal four-chamber view acquired using 3D full volume in patients with D-transposition of the great arteries, after a Mustard procedure. (a) There is narrowing within the systemic venous

baffle in this case (SVB). (b) In an image from a different patient the systemic venous baffle and the pulmonary venous baffle (PVB) appear unobstructed. LV left ventricle, RV right ventricle

Because of these issues, follow up interventions are often required. The use of 3D TEE guidance is frequently very useful to visualize the complex systemic and pulmonary venous baffles. A collection of the most useful midesopha-

geal 3D full volume ME 4-Ch, long axis and short axis views, X-plane long and short axis views, and Live 3D DTG RVOT views are presented in Figs. 24.24, 24.25, 24.26, and 24.27, and Videos 24.13 and 24.14.

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

Fig. 24.25  Images from a patient with D–transposition of the great arteries after Mustard procedure. (a) Midesophageal aortic valve short axis equivalent view with 3D full volume acquisition, showing narrowing of the superior vena cava (SVC) limb of the systemic venous baffle. The aorta (Ao) is positioned anterior and rightward with respect to the pulmonary

b

artery (PA). The pulmonary venous baffle (PVB) is located posteriorly and is unobstructed. (b) Deep transgastric right ventricular outflow tract live 3D acquisition view demonstrating stenosis in the left ventricular outflow tract beneath the pulmonary valve (SubPS). LV left ventricle, MV mitral valve, RV right ventricle, SVB systemic venous baffle

a

b

c

d

Fig. 24.26  Midesophageal long and short axis views of the systemic venous baffle (SVB) and pulmonary venous baffle (PVB) in D-transposition of the great arteries after a Mustard procedure. (a)

777

Long axis X-plane view of the Mustard baffles. (b) Short axis X-plane view of the Mustard baffles. (c) Live 3D long axis view of the Mustard baffles. (d) Live 3D short axis view of the Mustard baffles

778

a

V. W. Cui and D. A. Roberson

b

Fig. 24.27  Live 3D acquisition deep transgastric right ventricular outflow tract views of D-transposition of the great arteries after the Mustard procedure. (a) The pulmonary venous baffle (PVB) connects to the right ventricle (RV) in unobstructed fashion. The RV is enlarged and connects to the anteriorly positioned aorta (Ao). (b) The systemic venous

baffle (SVB) connects to the left ventricle (LV) through the mitral valve (MV). The left ventricle connects to the pulmonary artery (PA), positioned posterior to the aorta. The most posterior structure seen in this figure corresponds to a portion of the PVB

Atrial Flutter

is important to exclude the presence of an intracardiac thrombus, particularly, within the left atrial appendage. This is best imaged with the midesophageal left atrial appendage (ME LAA) view, using X-plane and Live 3D modes  (Fig. 24.28). Similarly, patients who have under-

The ever expanding and aging population of patients surviving with CHD has resulted in the increasing incidence of atrial flutter. Prior to cardioversion in these patients, it

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

779

a

b

c

Fig. 24.28  Views of the left atrial appendage obtained in a patient with atrial flutter prior to cardioversion. (a) Case example of simultaneous biplane 2D imaging referred to as X-plane echocardiography, showing a midesophageal left atrial appendage view in orthogonal planes of a

normal left atrial appendage (LAA) that is free of thrombus. (b) Live 3D frontal view of the same normal LAA. (c) The orifice of the LAA is demonstrated using live 3D

gone the Fontan procedure are prone to thrombus formation within the Fontan pathway, particularly those with a classic atriopulmonary connection. Most often, X-plane (Fig.  24.29) and Live 3D (Fig.  24.30, Videos 24.15 and 24.16) are the best modalities to search for thrombi within the Fontan pathway.

Implantable Cardioverter-Defibrillator Implantable defibrillator devices have proven to be successful treatment for the prevention of sudden death in patients with hypertrophic cardiomyopathy. However, the device leads are somewhat stiff, the hearts hyperdynamic, and the

780

V. W. Cui and D. A. Roberson

a

b

c

d

Fig. 24.29  Simultaneous biplane echocardiograms (X-plane imaging) of a classic Fontan connection with very slow flow velocity apparent as spontaneous contrast. In the top row is the simultaneous biplane 2D echo depiction with a midesophageal bicaval view (a) and midesopha-

geal aortic valve short axis view (b) focusing on this region. In the bottom row the corresponding color Doppler flow mapping bicaval (c) and short axis views (d) are demonstrated

children with these implanted devices are often physically active. Therefore lead problems such as fracture and rarely perforation can occur (Fig.  24.31, Video 24.17). Live 3D mode is often very useful to analyze the position of intracardiac hardware and assess the size of a pericardial effusion.

Resynchronization Therapy In patients with ventricular systolic dysfunction and dyssynchrony, the use of multi-lead ventricular pacing may result in improved function and synchrony [30–32]. Using 3D TEE

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

a

b

c

d

Fig. 24.30  Figure depict images from four different patients with classic Fontan connections and various degrees of spontaneous contrast, sludge and a thrombus as seen is various views. (a) An organized thrombus is present. See Video 24.15 (b) There is very dense spontane-

a

Fig. 24.31  Hypertrophic cardiomyopathy with defibrillator lead perforation of the right ventricle (RV) and pericardial effusion. (a) Transgastric apical short axis 3D view of the hypertrophied left ventricle (LV) and pericardial effusion (E). (b) A midesophageal right ven-

781

ous contrast (sludge). See Video 24.16 (c) A moderate amount of spontaneous contrast is noted. (d) A smaller amount of spontaneous contrast (smoke) is seen. AoV aortic valve, LA left atrium, PA pulmonary artery

b

tricular inflow-outflow view with live 3D acquisition demonstrating the defibrillator lead (arrow) perforating the RV anterior wall near the apex. AoV aortic valve, RVOT right ventricular outflow tract

782

V. W. Cui and D. A. Roberson

and quantitative function and synchrony software, the measurement of ejection fraction, synchrony index and determination of the site of most delayed contraction can be performed during the procedure in order to appropriately place the ventricular leads. This information can be used to optimize lead placement and the adjustment of V-V intervals in order to enhance ventricular performance as illustrated in Fig. 24.32.

Tetralogy of Fallot with Melody Valve Severe pulmonary valve insufficiency after tetralogy of Fallot will often require pulmonary valve replacement which can be achieved with a transcatheter method (Melody

a

b

c

d

Fig. 24.32  Patient with double inlet left ventricle after septation procedure and bidirectional Glenn undergoing resynchronization therapy with multi-lead pacing to improve ventricular systolic function. Quantitative data was obtained using commercially available software able to measure 3D derived ejection fraction (EF) and dyssynchrony index (Tmsv 16 SD) before and after pacing with two ventricular leads

valve) [33, 34]. Live 3D, X-plane and X-plane plus color Doppler often provide useful information during this procedure. See Figs. 24.33, 24.34 and 24.35 and Videos 24.18, 24.19, 24.20.

Double Outlet Right Ventricle Repair Double outlet right ventricle repair may involve a long baffle connecting the LV through a VSD to the aorta. Imaging this complex connection may be achieved with X-plane, X-plane + color Doppler and 3D full volume acquisition with subsequent cropping. See Figs.  24.36, 24.37, 24.38, and respective Videos 24.21, 24.22 and 24.23.

(biV-pace). (a) The midesophageal four-chamber full volume view is seen. (b) The quantitative 3D data for left ventricular systolic function and synchrony are presented. (c) Dyssynchronous regional time volume curves are seen. (d) Improved but still mildly abnormal regional time volume curves are depicted. LA left atrium, LV left ventricle, ml milliliters, RA right atrium, RV right ventricle

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

783

Fig. 24.33  Live 3D dual volume layout views of a transcatheter Melody valve in a patient with Tetralogy of Fallot (TOF) and pulmonary valve insufficiency. On the left is the pulmonary artery view aspect and on the right is the right ventricular outflow tract (RVOT) aspect. Using the dual volume layout display both sides of the valve can be viewed simultaneously

Fig. 24.34  Simultaneous short axis (left panel) and long axis (right panel) views of the Melody valve (red arrow) using the X-plane biplane echo method, obtained from a midesophageal ascending aorta short axis view. The M—line or line of dissection (not visible on this fig-

ure) is placed through the valve on the left reference image in order to develop the orthogonal image seen on the right image. Ao aorta, MPA main pulmonary artery, RPA right pulmonary artery

784

V. W. Cui and D. A. Roberson

Fig. 24.35  Color Doppler flow mapping has now been added to the images displayed in Fig. 24.34. Ao aorta, MPA main pulmonary artery

Fig. 24.36  Double outlet right ventricle (DORV) after left ventricle (LV) to aortic baffle repair, with subaortic stenosis (sub-AS). The X-plane orthogonal 2D echo views of the small ventricular septal defect (VSD). The reference image seen on the left shows the baffle from the

native VSD to the aorta (Ao). In the right panel is seen the en face view of the left ventricular outflow tract (LVOT)/native VSD. LA left atrium, LVOT left ventricular outflow track, PA pulmonary artery, RA right atrium, RV right ventricle

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

785

Fig. 24.37  Color Doppler flow mapping has been added to the above X-plane echocardiographic images from Fig. 24.36, showing aliasing across the area of the native ventricular septal defect. Ao aorta, LA left atrium, LV left ventricle

Fig. 24.38  Full volume acquisition from the patient in Fig. 24.36. The 3 panel multi-planar review format shows the 3D data set on top, the reference 2D image on the bottom left and the orthogonal 2D image

bottom right. The baffle connecting the left ventricle (LV) to the aorta (Ao) is long and narrow. LA left atrium, IVS interventricular septum

786

 ongenitally Corrected Transposition Palliated C with ASD stent and PA band

V. W. Cui and D. A. Roberson

This complex anomaly often requires multiple interventions either to promote better systemic RV function, correct associated anomalies or attempt to optimize for double switch

procedure. We have found 3D TEE methods useful to demonstrate the anatomy and color Doppler blood flow in these lesions. See Figs. 24.39, 24.40, 24.41 and 24.42, and Videos 24.24, 24.25, 24.26, and 24.27. In this particular case we found 3D full volume with cropping, X-plane and X-plane + color Doppler useful.

Fig. 24.39  A case of congenitally corrected transposition of the great arteries (L-TGA), atrial septal defect (ASD) stent and pulmonary artery band. The ASD stent is seen in the reference (left) and orthogonal

(right) views simultaneously by using X- plane echocardiography. The stent is in good position and fully expanded. LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

787

Fig. 24.40  Color Doppler flow mapping in the X-plane modality has been added to the image from Fig. 24.39. LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

Fig. 24.41  Full volume acquisition in the patient from Fig. 24.39 with the elevation plane cropped approximately 50% shows the stent in the atrial septal defect with good position and configuration. LA left atrium, LV left ventricle, RA right atrium, RV right ventricle

788

Fig. 24.42 Deep transgastric simultaneous orthogonal X—plane views with Color Doppler flow mapping of the pulmonary artery (PA) band, in the patient from Fig. 24.39. These particular TEE views pro-

Fig. 24.43  Live 3D view (midesophageal aortic valve short axis) of a truncal valve leaflet perforation

V. W. Cui and D. A. Roberson

vide an excellent angle for spectral Doppler evaluation of the PA band velocity. LV left ventricle, RA right atrium

Fig. 24.44  Hypoplastic left heart syndrome, post Norwood procedure. Live 3D en face view of the neo-aortic valve (NeoAoV). The hypoplastic native aortic root from which the coronary arteries arise is seen. Ao aorta, LCA left coronary artery, RCA right coronary artery

Truncus arteriosus

Hypoplastic Left Heart S/P Fontan Procedure

In truncus arteriosus,  the solitary  truncal valve is often abnormal. The truncal valve anatomy can be well-seen using the ME AoV SAX view and Live 3D imaging See Fig. 24.43 and Video 24.28.

Following a Norwood procedure, the neo-aortic and native aortic valves can be seen by a live 3D en face image (Fig. 24.44, Video 24.29). A Fontan fenestration closure can also be evaluated by 3D TEE. In this case we used live nar-

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

row sector 3D with the appropriate adjustments in sample size, orientation and view aspect as well as X-plane and X-plane + color to guide and analyze Fontan fenestration closure (see Fig. 24.45 and Videos 24.30 and 24.31).

789

Bioprosthetic Mitral Valve The 4 panel MPR format is used to display three 2D views plus the 3D image simultaneously. This format is used for clearly demonstrating multiple views of a structure and is the

a

b

c

Fig. 24.45  Live 3D view of a Fontan fenestration closure. (a) The fenestration closure device is seen from the Fontan side. (b) A small residual shunt is seen in the reference image. (c) The residual shunt is also seen in the orthogonal image. F Fontan, LA left atrium

790

V. W. Cui and D. A. Roberson

Fig. 24.46  4 panel MPR (multiplane reconstruction format) views of the bioprosthetic mitral valve. The green panel shows the reference 2D image, red panel shows the orthogonal 2D image, blue panel shows the cross sectional 2D image and the white panel shows the 3D image. The

top 4 panels are during systole (mitral valve closed) and the bottom 4 are during diastole (mitral valve open). This view is used to demonstrate multiple simultaneous 2D views plus a 3D view of the mitral valve. LA left atrium, LV left ventricle, MV mitral valve

default mode for quantitation software and some cropping tools (See Fig. 24.46 and Video 24.32). Live 3D with dual volume layout, as seen in Fig. 24.47 and Video 24.33, allows simultaneous visualization of opposite sides of the bioprosthetic mitral valve. This approach is useful for AV valves, ASDs, VSDs, the LVOT, and the AoV.

Congenital Mitral Valve Stenosis The following is a case presentation of a patient with congenital mitral valve stenosis. The Live 3DE modalities most often used for AV valves are X-plane and Live 3D Zoom with dual volume layout as demonstrated in Figs. 24.48 and 24.49 and Videos 24.34 and 24.35.

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

791

Fig. 24.47  Bioprosthetic mitral valve from Fig. 24.46. Live 3D echo views acquired with the 3D zoom mode and displayed with dual volume layout which demonstrates the atrial and ventricular views of the valve simultaneously

Fig. 24.48  Orthogonal X-plane biplane echo views obtained with the X-plane modality showing congenital mitral valve stenosis (arrow). The reference image is on the left and the orthogonal image on the right. LA left atrium, LV left ventricle, RV right ventricle

792

V. W. Cui and D. A. Roberson

Fig. 24.49  Live 3D echo views acquired with the 3D zoom mode and displayed with dual volume layout demonstrating the stenotic mitral valve (from Fig. 24.48) from atrial and ventricular aspects. AoV aortic

valve, LA left atrium, LAA left atrium appendage, LVOT left ventricular outflow tract, MV mitral valve, RA right atrium

Subaortic Stenosis

MPR provides a display format with the 3D view on top, the reference 2D view on the bottom left and the orthogonal (to the reference image) on the bottom right (see Fig. 24.52 and Video 24.39). This displayed MPR format is the one  most commonly used on-cart intraoperatively and in the catheterization laboratory. This format is also important to use when acquiring full volume data sets, because one must inspect the bottom right panel to evaluate for stitch artifact and adequacy of 3D volume size. The 3D Zoom mode with dual volume layout (Fig. 24.53 and Video 24.40) was used to demonstrate a muscular VSD from both sides of the ventricular septum simultaneously. 

In this case with subaortic membrane, the 4 panel MPR display demonstrates the pathology clearly with simultaneous three 2D views plus a 3D views in Fig. 24.50 and associated Video 24.36. The aortic valve view and the LVOT view are simultaneously displayed using the 3D Zoom acquisition mode plus dual volume layout display as seen in Fig. 24.51 plus Videos 24.37 and 24.38.

Tricuspid Atresia and Extracardiac Fontan The example below presents a  3 panel MPR display of an extracardiac Fontan in a patient with tricuspid atresia. The

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

Fig. 24.50  Four panel MPR (multiplane reconstruction format) views of a stenotic subaortic membrane (arrow). The green panel shows the reference 2D image, red panel shows the orthogonal 2D image, blue

793

panel shows the cross sectional 2D image and the lower right panel shows the 3D image. The small LVOT orifice is marked with (asterisk). Ao aorta, LV left ventricle

Fig. 24.51  The subaortic stenotic membrane (arrow) and narrow left ventricular outflow tract (LVOT, asterisk) views were acquired using 3D zoom mode and displayed with dual volume layout which shows the aortic side and the LVOT side of the obstruction, in the patient from Fig. 24.50

794

V. W. Cui and D. A. Roberson

a

b

c

Fig. 24.52  Three panel MPR display of a live 3D acquisition of an extra-cardiac Fontan in a patient with tricuspid atresia. (a) Live 3D long axis view, (b) 2D reference image long axis view, (c) Orthogonal 2D short axis view. LA left atrium

Fig. 24.53  Demonstration of a muscular ventricular septal defect (VSD, asterisk) in a patient with tricuspid atresia using 3D echo views acquired with the 3D zoom mode, and displayed with dual volume layout. AoV aortic valve, LV left ventricle, RV, right ventricle

24  Clinical Applications of Three Dimensional Transesophageal Echocardiography in Congenital Heart Disease

Summary It is clear from these illustrative cases that 3D TEE in its current form has important and very useful clinical applications. Unique en face views, as well as complementary views, can be obtained that enhance the assessment of anatomy, assist interventional device placement, and facilitate surgical interventions and electrophysiologic procedures. With practice, these images can be obtained rapidly, consistently and ­reproducibly. Further revisions of 3D TEE hardware and software will likely continue to improve the ease of application and image quality of 3D TEE for the evaluation of CHD and related issues.

Questions and Answers 1. Current guidelines recommend that 3D TEE be performed during which catheter-based intervention? (a) Secundum atrial septal defect (b) Coarctation stenting (c) Pulmonary valve implantation (d) Aortic valve balloon dilation (e) Pulmonary artery stenting Answer: a Explanation: Both 2D and 3D TEE are very much indicated for catheter-based closure of secundum atrial septal defects and and muscular ventricular septal defects because of their ability to visualize the atrial/ ventricular septa and the relation of the devices to the septa and surrounding structures. For the other procedures, 2D and 3D TEE can be performed but they do not add as much important information, and are not considered essential. 2. Current guidelines recommend that 3D TEE be performed during which of the following surgical treatments? (a) Extracardiac Fontan procedure (b) Tricuspid valvuloplasty (c) Epicardial pacemaker (d) Bidirectional Glenn procedure (e) Pulmonary artery unifocalization Answer: b Explanation: Of all the choices, 3D TEE is considered the most important for assessment of valvular repair. It does not add as much information for pulmonary artery unifocalization, bidirectional Glenn or extracardiac

795

Fontan procedures, and is not routinely indicated for epicardial pacemaker placement. 3. 3D TEE acquisition modalities include all of the following except (a) Live small sector 3D imaging (b) Live wide sector 3D imaging (c) ECG gated multi-beat large sector imaging (d) Biplane echocardiography (e) Live 3D spectral Doppler Answer: e Explanation: All of the above modalities are available for 3D TEE, except for 3D spectral Doppler, which is not. 4. Currently available 3D TEE equipment has which of the following limitations? Choose all that apply. (a) Relatively large transducer size for many children. (b) Inability to perform 2D imaging with the 3D TEE transducer (c) Inability to obtain more than one 2D imaging plane from a 3D dataset. (d) Limited acquisition modalities. (e) Limited cropping modalities. Answer: a Explanation: The current 3D TEE probes are not generally indicated for patients