Operative Techniques in Vascular Surgery [1 ed.]

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Editor Ronald L. Dalman MD Chidester Professor of Surgery Division Chief of Vascular Surgery Stanford University School of Medicine Stanford, California

Editor-in-Chief Michael W. Mulholland, MD, PhD Professor of Surgery and Chair Department of Surgery University of Michigan Medical School Ann Arbor, Michigan

Contributing Authors Georges E. Al Khoury, MD Assistant Professor of Surgery Department of Surgery Division of Vascular Surgery University of Pittsburg School of Medicine Pittsburgh, Pennsylvania George J. Arnaoutakis, MD Fellow in Cardiothoracic Surgery Hospital of the University of Pennsylvania Philadelphia, Pennsylvania Ramin E. Beygui, MD, FACS Associate Professor Department of Cardiothoracic Surgery Stanford University Stanford, California Elizabeth Blazick, MD Fellow Division of Vascular and Endovascular Surgery Massachusetts General Hospital Boston, Massachusetts Danielle E. Cafasso, DO Department of Surgery Tripler Army Medical Center Honolulu, Hawaii

Rabih A. Chaer, MD Associate Professor of Surgery Department of Surgery Division of Vascular Surgery University of Pittsburgh School of Medicine Pittsburgh, Pennsylvania Venita Chandra, MD Clinical Assistant Professor Department of Surgery Division of Vascular and Endovascular Surgery Stanford University School of Medicine Stanford, California James Chang, MD Chief Division of Plastic and Reconstructive Surgery Professor of Surgery and Orthopedic Surgery Stanford University Medical Center Stanford, California Roberto Chiesa, MD Division of Vascular Surgery Scientific Institute Ospedale San Raffaele Chair of Vascular Surgery School of Medicine Vita-Salute San Raffaele University Milan, Italy Efrem Civilini, MD Division of Vascular Surgery Scientific Institute Ospedale San Raffaele Chair of Vascular Surgery School of Medicine Vita-Salute San Raffaele University Milan, Italy Mark F. Conrad, MD Assistant Professor of Surgery Division of Vascular and Endovascular Surgery Massachusetts General Hospital Boston, Massachusetts Ronald L. Dalman, MD

Chidester Professor of Surgery Division Chief of Vascular Surgery Stanford University School of Medicine Stanford, California Scott M. Damrauer, MD Instructor in Surgery Fellow Department of Surgery Division of Vascular Surgery and Endovascular Therapy Hospital of the University of Pennsylvania Philadelphia, Pennsylvania Narasimham L. Dasika, MD Associate Professor of Radiology Department of Radiology Division of Vascular and Interventional Radiology University of Michigan Health System Ann Arbor, Michigan Brian G. DeRubertis, MD Associate Professor of Surgery Department of Surgery Division of Vascular Surgery David Geffen School of Medicine at University of California, Los Angeles Los Angeles, California Michael J. Englesbe, MD Associate Professor of Surgery Department of Surgery University of Michigan Medical School Ann Arbor, Michigan Julie Ann Freischlag, MD William Steward Halsted Professor Chair Department of Surgery The Johns Hopkins Hospital Johns Hopkins Medical Institutions Baltimore, Maryland Michael G. Galvez, MD Resident

Department of Surgery Division of Plastic and Reconstructive Surgery Stanford University School of Medicine Stanford, California Sung Wan Ham, MD Vascular Surgery Fellow Vascular Surgery Division University of Southern California Los Angeles County Medical Center Los Angeles, California E. John Harris, Jr. MD Professor of Surgery Stanford University School of Medicine Stanford, California Grace Huang, MD Resident Surgery University of Southern California Los Angeles County Medical Center Los Angeles, California Zhen S. Huang, MD Fellow in Vascular and Endovascular Surgery Department of Vascular and Endovascular Surgery New York-Presbyterian Hospital Weill Cornell Medical Center New York, New York Nathan Itoga, MD Vascular Surgery Resident Department of Surgery Stanford University School of Medicine Stanford, California Geetha Jeyabalan, MD Assistant Professor of Surgery Department of Surgery Division of Vascular Surgery University of Pittsburgh Medical Center Pittsburgh, Pennsylvania Karina S. Kanamori, MD

Clinical Research Fellow Division of Vascular and Endovascular Surgery Mayo Clinic Rochester, Minnesota Sharon C. Kiang, MD Vascular Surgery Fellow Department of General Surgery Division of Vascular Surgery Ronald Reagan UCLA Medical Center Los Angeles, California Alexander Kulik, MD, MPH, FRCSC Cardiovascular Surgeon Lynn Heart & Vascular Institute Boca Raton Regional Hospital Affiliate Associate Professor Charles E. Schmidt College of Medicine Florida Atlantic University Boca Raton, Florida Gregory J. Landry, MD Associate Professor of Surgery Knight Cardiovascular Institute Oregon Health & Science University Portland, Oregon Cheong J. Lee, MD Assistant Professor of Surgery Division of Vascular Surgery Medical College of Wisconsin Milwaukee, Wisconsin Jason T. Lee, MD Associate Professor of Vascular Surgery Department of Surgery Stanford University School of Medicine Stanford, California Peter H. U. Lee, MD, MPH Clinical Instructor Department of Cardiothoracic Surgery Stanford University Stanford, California

W. Anthony Lee, MD, FACS Director Endovascular Program Lynn Heart & Vascular Institute Boca Raton Regional Hospital Boca Raton, Florida Amit K. Mathur, MD Clinical Lecturer Transplant Fellow Section of Transplantation Surgery Department of Surgery University of Michigan Health System Ann Arbor, Michigan Germano Melissano, MD Division of Vascular Surgery Scientific Institute Ospedale San Raffaele Chair of Vascular Surgery School of Medicine Vita-Salute San Raffaele University Milan, Italy Matthew Mell, MD Associate Professor of Surgery Division of Vascular Surgery Stanford University School of Medicine Stanford, California Joseph L. Mills, Sr., MD Chief Department of Surgery Division of Vascular and Endovascular Surgery Co-Director Southern Arizona Limb Salvage Alliance University of Arizona Health Sciences Center Tucson, Arizona Mark D. Morasch, MD, FACS Vascular Surgeon Heart and Vascular Center St. Vincent Healthcare Billings, Montana Gustavo S. Oderich, MD

Professor of Surgery Director Endovascular Therapy Director Edward Rogers Clinical Research Fellowship Division of Vascular and Endovascular Surgery Mayo Clinic Rochester, Minnesota F. Gallardo Pedrajas, MD Consultant Angiology and Vascular Surgery Hospital University of Santiago Santiago de Compostela Compostela, Spain Thomas Reifsnyder, MD Assistant Professor Chief Vascular Laboratory Department of Surgery Johns Hopkins Bayview Medical Center Johns Hopkins Medical Institutions Baltimore, Maryland Enrico Rinaldi, MD Scientific Institute Ospedale San Raffaele Division of Vascular Surgery Chair of Vascular Surgery School of Medicine Vita-Salute San Raffaele University Milan, Italy Darren B. Schneider, MD Associate Professor of Surgery Chief of Vascular and Endovascular Surgery Weill Cornell Medical College New York-Presbyterian Hospital Weill Cornell Medical Center New York, New York Peter A. Schneider MD Department of Surgery Division of Vascular Therapy Hawaii Permanente Medical Group Kaiser Foundation Hospital

Honolulu, Hawaii Benjamin W. Starnes, MD, FACS Professor and Chief of Vascular Surgery Department of Surgery University of Washington Seattle, Washington Robert W. Thompson, MD Professor of Surgery Radiology Cell Biology Physiology Vice Chair for Research Department of Surgery Director Washington University Thoracic Outlet Syndrome Center Barnes-Jewish Hospital Washington University School of Medicine St. Louis, Missouri Brant W. Ullery, MD Vascular Surgery Fellow Department of Surgery Stanford University School of Medicine Stanford, Carolina Vinit N. Varu, MD Vascular Surgery Fellow Department of Surgery Stanford University School of Medicine Stanford, California Ranjith Vellody, MD Assistant Professor of Radiology Division of Vascular and Interventional Radiology Department of Radiology University of Michigan Health System Ann Arbor, Michigan Chandu Vemuri, MD Fellow in Vascular Surgery Department of Surgery Barnes-Jewish Hospital

Washington University School of Medicine St. Louis, Missouri Fred Weaver, MD, MMM Professor of Surgery Chief Division of Vascular Surgery and Endovascular Therapy Keck Hospital University of Southern California Los Angeles, California Edward Y. Woo, MD Director Regional Vascular Program MedStar Washington Hospital Center Chief Vascular Surgery MedStar Georgetown University Hospital Washington, DC Mohamed A. Zayed, MD, PhD, RPVI Assistant Professor of Surgery Section of Vascular Surgery Washington University School of Medicine St. Louis, Missouri Luke X. Zhan, MD, PhD Resident Department of Surgery Division of Vascular and Endovascular Surgery Southern Arizona Limb Salvage Alliance Tucson, Arizona Wei Zhou, MD Professor of Surgery Stanford University Stanford, California Chief Vascular Surgery VA Palo Alto Health Care System Palo Alto, California

2015 Lippincott Williams & Wilkins Philadelphia Two Commerce Square, 2001 Market Street, Philadelphia, PA 19103 USA 978-1-4511-9020-5

Acquisitions Editor: Keith Donnellan Product Development Editor: Brendan Huffman Production Project Manager: David Saltzberg Design Coordinator: Doug Smock Senior Manufacturing Manager: Beth Welsh Marketing Manager: Daniel Dressler Prepress Vendor: Absolute Service, Inc. Copyright © 2015 Wolters Kluwer Health All rights reserved. This book is protected by copyright. No part of this book may be reproduced or transmitted in any form or by any means, including as photocopies or scanned-in or other electronic copies, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews. Materials appearing in this book prepared by individuals as part of their official duties as U.S. government employees are not covered by the above-mentioned copyright. To request permission, please contact Wolters Kluwer Health at Two Commerce Square, 2001 Market Street, Philadelphia, PA 19103, via email at [email protected], or via our website at lww.com (products and services). 987654321 Printed in China Library of Congress Cataloging-in-Publication Data Operative techniques in vascular surgery/editor, Ronald L. Dalman; editor-in-chief, Michael W. Mulholland. p.; cm. Includes bibliographical references and index. ISBN 978-1-4511-9020-5 (alk. paper) I. Dalman, Ronald L., editor. II. Mulholland, Michael W., editor. III. Operative techniques in surgery. Contained in (work): IV. Operative techniques in transplantation surgery. Contained in (work): [DNLM: 1. Vascular Surgical Procedures—methods. 2. Carotid Arteries—surgery. 3. Vascular Diseases— surgery. WG 170] RD120.7 617.9′54—dc23 2015004608 This work is provided “as is,” and the publisher disclaims any and all warranties, express or implied, including any warranties as to accuracy, comprehensiveness, or currency of the content of this work.

This work is no substitute for individual patient assessment based upon healthcare professionals’ examination of each patient and consideration of, among other things, age, weight, gender, current or prior medical conditions, medication history, laboratory data, and other factors unique to the patient. The publisher does not provide medical advice or guidance, and this work is merely a reference tool. Healthcare professionals, and not the publisher, are solely responsible for the use of this work including all medical judgments and for any resulting diagnosis and treatments. Given continuous, rapid advances in medical science and health information, independent professional verification of medical diagnoses, indications, appropriate pharmaceutical selections and dosages, and treatment options should be made and healthcare professionals should consult a variety of sources. When prescribing medication, healthcare professionals are advised to consult the product information sheet (the manufacturer’s package insert) accompanying each drug to verify, among other things, conditions of use, warnings, and side effects and identify any changes in dosage schedule or contradictions, particularly if the medication to be administered is new, infrequently used or has a narrow therapeutic range. To the maximum extent permitted under applicable law, no responsibility is assumed by the publisher for any injury and/or damage to persons or property, as a matter of products liability, negligence law or otherwise, or from any reference to or use by any person of this work. LWW.com

Dedication The love and support of my wife, Jocelyn J. Dunn MD, continues to enable all my professional accomplishments. Ronald L. Dalman

Series Preface Operative therapy is complex, technically demanding, and rapidly evolving. Although there are a number of standard textbooks that cover aspects of general, thoracic, vascular, or transplant surgery, Operative Techniques in Surgery is unique in offering a comprehensive treatment of contemporary procedures. Open operations, laparoscopic procedures, and newly described robotic approaches are all included. Where alternative or complementary approaches exist, all are provided. The scope and ambition of the project is one of a kind. The series is organized anatomically in sections covering thoracic surgery, upper gastrointestinal surgery, hepatopancreatico-biliary surgery, and colorectal surgery. Breast surgery, endocrine surgery, and topics related to surgical oncology are included in a separate volume. Modern approaches to vascular surgery and transplantation surgery are also covered in separate volumes. The series editors are renowned surgeons with expertise in their respective fields. Each is a leader in the discipline of surgery, each recognized for superb surgical judgment and outstanding operative skill. Breast surgery, endocrine procedures, and surgical oncology topics were edited by Dr. Michael Sabel of the University of Michigan. Thoracic and upper gastrointestinal surgery topics were edited by Dr. Mary Hawn of the University of Alabama at Birmingham, with Dr. Steven Hughes of the University of Florida directing the volume on hepatopancreatico-biliary surgery. Dr. Daniel Albo of Baylor College of Medicine directed the volume dedicated to colorectal surgery. Dr. Ronald Dalman of Stanford University edited topics related to vascular surgery, including both open and endovascular approaches. The discipline of transplantation surgery is represented by Dr. Michael Englesbe of the University of Michigan. In turn, the editors have recruited contributors that are world-renowned; the resulting volumes have a distinctly international flavor. Surgery is a visual discipline. Operative Techniques in Surgery is lavishly illustrated with a compelling combination of line art and intraoperative photography. The illustrated material was all executed by a single source, Body Scientific International, to provide a uniform style emphasizing clarity and strong, clean lines. Intraoperative photographs are taken from the perspective of the operating surgeon so that operations might be visualized as they would be performed. The result is visually striking, often beautiful. The accompanying text is intentionally spare, with a focus on crucial operative details and important aspects of postoperative management. The series is designed for surgeons at all levels of practice, from surgical residents to advanced practice fellows to surgeons of wide experience. The incredible pace at which surgical technique evolves means that the volumes will offer new insights and novel approaches to all surgeons.

Operative Techniques in Surgery would be possible only at Wolters Kluwer Health, an organization of unique vision, organization, and talent. Brian Brown, executive editor, Keith Donnellan, acquisitions editor, and Brendan Huffman, product development editor, deserve special recognition for vision and perseverance. Michael W. Mulholland, MD, PhD

Preface The pace of innovation in vascular surgery continues to accelerate. Driven by surgeons and industry alike, catheter-based, image-guided intervention, coupled with minimally invasive or “hybrid” exposures, are both revolutionizing care of the vascular patient. The surgeon-authors featured herein represent the vanguard of this movement—leveraging all the advantages inherent in new technology while maintaining fidelity with the fundamental principles of open surgery. As part of the series Operative Techniques in Surgery, this atlas was created to provide a comprehensive reference for practicing surgeons looking to incorporate new skills in vascular disease management as well as trainees at all levels looking for expert guidance. Familiarity of the reader with endovascular skills as well as a representative range of device options for arterial and venous intervention are assumed—those interested in more background should consult a fundamental reference first. Successful completion of this project was enabled by the steady and encouraging guidance of the series editor, Dr. Michael W. Mulholland, and the professional editorial and project management staff at Wolters Kluwer Health, especially Brendan Huffman and Keith Donnellan. Dr. Jason Lee provided invaluable structural guidance and contributor recommendations. On behalf of everyone involved on this project, it is our shared hope that the thousands of hours of operative insights condensed in this edition will inspire the next generation of vascular specialists. Ronald L. Dalman, MD

Chapter 1 Arch and Great Vessel Reconstruction with Debranching Techniques W. Anthony Lee Alexander Kulik

DEFINITION An aortic arch aneurysm is defined as dilation of the aortic arch to greater than 5 cm in diameter. Rarely occurring in isolation, aneurysms of the aortic arch are often extensions of aneurysms present in the ascending or descending aorta. Causes of aortic arch aneurysms included atherosclerotic degeneration, cystic medial degeneration, aortic dissection, congenital aortopathy (i.e., bicuspid aortic valve), penetrating aortic ulcer, previous traumatic transection (chronic pseudoaneurysm), and previously repaired aortic coarctation (postsurgical pseudoaneurysm). Aortic arch aneurysms have traditionally been repaired with graft replacement of the aorta, with or without an elephant trunk, using cardiopulmonary bypass and deep hypothermic circulatory arrest. With the advent of thoracic endovascular aortic repair (TEVAR), debranching of the brachiocephalic vessels is a recently developed technique that takes advantage of the reduced surgical trauma associated with stent grafting.1 Debranching functionally extends the proximal landing zone by repositioning the inflow of the brachiocephalic arteries toward the proximal ascending aorta. This facilitates endovascular stent graft repair of the aortic aneurysm by allowing stent coverage across the ostia of the arch vessels, producing a stable and fixed proximal landing zone in the ascending aorta.

PATIENT HISTORY AND PHYSICAL FINDINGS Aortic arch aneurysms are usually diagnosed as incidental findings noted on imaging studies, such as a chest x-ray or computed tomography (CT) scan, to evaluate other concurrent medical conditions. Most patients have no symptoms from their aneurysms. Symptoms, if they exist, may include chest or back pain from aneurysmal growth or those associated with compression of adjacent structures (i.e., trachea, esophagus). Hoarseness may develop from stretching of the left recurrent laryngeal nerve (Ortner’s syndrome). Acute chest or back pain, with or without signs of shock, should raise the suspicion of impending aortic rupture and/or acute aortic dissection. Additional details regarding a patient’s past medical history should be gathered, including a history of previous coronary intervention, previous cardiac surgery, known valvular heart disease, previous aneurysm surgery, or a family history of aortopathy. The physical examination is often unremarkable. However, attention should be directed to the presence of aortic valve insufficiency (diastolic murmur, widened pulse pressure), previous surgical incisions, and the presence of concomitant peripheral vascular disease.

IMAGING AND OTHER DIAGNOSTIC STUDIES Although a routine chest x-ray may be the first imaging test to note an aortic arch abnormality, further imaging is necessary, including a CT scan of the aorta (FIG 1) and an echocardiogram. An arterial phase CT angiogram should evaluate the entire length of the aorta, from the level of the skull base proximally to the femoral heads distally, to ensure visualization of the vertebral and iliofemoral arteries,

respectively. The CT images are then processed using 3D imaging software for case planning and device selection. A magnetic resonance imaging (MRI) or a noncontrast CT scan will not suffice. A transthoracic (2D) echocardiogram should be performed to assess left and right ventricular function and to exclude the presence of significant valvular heart disease. Strong consideration should be given to evaluating the anatomy of the coronary arteries in the preoperative period. A CT coronary angiogram may be an option for younger patients or those with complex proximal aortic dissection. However, if there is a strong suspicion of coronary disease, then a preoperative conventional coronary angiogram should be performed, including those patients older than 40 years of age and those with a history of smoking.

SURGICAL MANAGEMENT Preoperative Planning Indications for repair of an aortic arch aneurysm include large aneurysmal size (>5.5 cm), rapid growth (>0.5 cm per year), the presence of chest pain or back pain unexplained by other causes, and compression of adjacent organs (esophagus, trachea, or left main bronchus).2 More aggressive size criteria may be applied for patients with Marfan’s syndrome (repair at 4.5 to 5 cm). However, stent graft outcomes appear less favorable in patients with P.2 connective tissue disease, and therefore, alternative surgical techniques (such as conventional aortic replacement surgery) should be considered.2 The presence of significant concurrent cardiac disease may alter the surgical approach. Should significant coronary artery or valvular heart disease be identified in the preoperative period, consideration may be given to performing concomitant coronary artery bypass grafting (CABG) or valve replacement at the time of the aortic debranching procedure. During the second stage of the arch repair, stent graft deployment in the distal ascending aorta may require the placement of a guidewire across the aortic valve into the left ventricular cavity. The presence of a mechanical aortic prosthetic valve, through which a guidewire and the delivery system cannot safely be placed, may require a single-stage approach with deployment of the stent graft at the time of debranching (see endovascular second stage). A bioprosthetic valve in the aortic position may allow for careful transvalvular introduction of devices, with preference to bovine pericardial valves over porcine valves. Selection of the ideal treatment strategy for repair of an aortic arch aneurysm remains controversial and is dictated by surgical experience and local area expertise. Aortic arch debranching and stent graft completion is an appealing repair option that avoids a thoracotomy incision and may avert the use of cardiopulmonary bypass and circulatory arrest. These types of hybrid procedures may be performed either as single- or twostage repairs. However, conventional open replacement of the entire aortic arch,3,4 or replacement of the ascending aorta and proximal arch with the creation of an elephant trunk followed by stent graft completion,1,5 should be considered as clinically indicated. Debranching of the aortic arch off the ascending aorta may not be applicable for a patient with an aortic arch aneurysm who has previously undergone cardiac surgery and who is too high-risk for consideration of redo sternotomy. In this case, an alternative option would include extra-anatomic debranching of the aortic arch (carotid-carotid, carotidsubclavian) followed by stent graft repair of the arch, with or without innominate artery chimney (snorkel) stenting.6

The preoperative CT scan requires careful review before undertaking an aortic arch debranching operation. Arch branch anatomy and appropriate landing zones need to be identified proximal and distal to the arch aneurysm, with criteria similar to those that apply for stent graft repair of a descending thoracic aortic aneurysm. Anatomic variations of the aortic arch anatomy may require modification of the debranching procedure. These include a bovine aortic arch (common trunk of the innominate and left common carotid), arch origin of left vertebral artery, and an aberrant right subclavian artery. The ascending aorta is typically 6 to 7 cm in length from the sinotubular junction to the innominate artery. Placement of the proximal inflow anastomosis as low as possible on the ascending aorta (just distal to the sinotubular junction) will result in an optimal 3- to 4-cm proximal landing zone for the stent graft repair. The largest currently available thoracic stent grafts are 42 to 46 mm in diameter. To provide a safe and durable proximal landing zone and avoid a proximal type I endoleak, we recommend replacement of an ascending aorta that is extremely short or if its diameter is 36 mm or larger. Open replacement of the ascending aorta would be performed at the time of the arch debranching procedure, with implantation of an aortic graft 34 mm or smaller. The size of the iliofemoral arteries is worth noting on the preoperative CT study. The external iliac arteries need to be larger than 7 mm in diameter to provide adequate vascular access to deliver the stent graft devices during the second stage. An iliac artery conduit may be needed if the iliofemoral arteries are extremely small or in the presence of severe calcification and occlusive disease. Alternatively, a single-stage antegrade introduction of the stent graft from the ascending aorta may be performed (see endovascular second stage) to avoid access problems from a retrograde iliofemoral approach. The diameters of the brachiocephalic arteries are measured on the preoperative CT scan to determine the interposition graft sizes for the debranching procedure. Most frequently, the size of the graft chosen for the innominate artery branch is 10 to 14 mm, with 6- to 8-mm grafts usually used for the left carotid and left subclavian arteries. Cerebral oximetry monitoring may be helpful for the aortic debranching procedure to monitor brain perfusion before and after clamping of the brachiocephalic arteries. For the second-stage endovascular procedure, cerebrospinal fluid (CSF) drains are placed preoperatively to reduce the risk of spinal cord ischemia if a significant length of the descending thoracic aorta is to be covered.

FIG 1 • Preoperative computed tomography (CT) angiogram of an aortic arch aneurysm.

Positioning For the arch debranching procedure, patients are positioned supine just as they are during standard cardiac surgical operations. Prepping is performed from the neck to the knees, with draping higher than usual to strategically provide access to the lower neck. The head may be turned slightly to the right to facilitate extension of the sternotomy incision proximally along the left sternocleidomastoid muscle.

AORTIC ARCH DEBRANCHING Although some advocate the use of a right thoracotomy incision or upper hemisternotomy, we prefer to expose the ascending aorta through a conventional sternotomy incision. This provides optimal visualization and control. The pericardium is incised and retracted. The ascending aorta is carefully mobilized to facilitate later placement of a proximally positioned sidebiting clamp. The space between the left side of the aorta and the pulmonary artery is dissected, with small vessels cauterized or clipped and divided. The ascending aorta is mobilized proximally down to the level of the aortic root (sinotubular junction) to enable identification (and avoid injury) to the right coronary artery. The brachiocephalic arteries are circumferentially exposed. The innominate vein is mobilized and retracted P.3 with an umbilical tape to facilitate exposure of the arch vessels (FIG 2). Uncommonly, the innominate vein requires ligation and division to aid in arch exposure. The left subclavian artery is often more posterior than expected, and exposure of this artery may be difficult. In these circumstances, the sternotomy incision may be extended superiorly and leftward along the sternocleidomastoid muscle. Alternatively, innominate and left carotid debranching may be combined with a left carotid-subclavian

bypass/transposition procedure, through a standard supraclavicular approach, obviating the need to expose the left subclavian artery through the sternotomy. Although a preformed bifurcated or multilimb graft may be used, these occupy a large footprint and reduce the length available for the ascending aortic landing zone. Instead, we prefer to construct a Ygraft by sewing a beveled smaller Dacron graft end-to-side to larger Dacron graft (FIG 3). The graft sizes are selected based on the measured diameters from the preoperative CT scan. Typically, a 10- or 12-mm graft is used for the innominate artery, and a 6- or 8-mm graft is used for the left carotid artery. Heparin is administered to achieve an activated clotting time (ACT) of 200 seconds. The blood pressure is lowered to 90 mmHg systolic, and an aortic sidebiting clamp is placed on the right anterolateral side (convexity) of the ascending aorta, as low as possible, with care not to compromise the right coronary artery. A retraction suture in the right atrial appendage may be needed to facilitate proximal aortic exposure. Consideration may be given to performing this and subsequent steps in the operation with cardiopulmonary bypass to provide optimal hemodynamic control during clamp application and removal and to improve brain protection with systemic cooling in the range of 32°C to 34°C. The proximal end of the larger (10 or 12 mm) graft is cut to the appropriate length so the Y-graft easily reaches the arch vessels. The graft is beveled and sewn end-to-side to the ascending aorta with a running 3-0 or 4-0 polypropylene suture (FIG 4). BioGlue may be applied to further support the anastomosis. The aortic clamp is gently released. A large clip may be placed across the heel of the anastomosis. This will help visualize the origin of the debranching graft from the ascending aorta and precisely define the proximal landing zone without the need for contrast during the second-stage endovascular procedure. The innominate artery is transected, and the proximal end is oversewn with two layers of 4-0 polypropylene. The distal large end of the Y-graft is then tunneled underneath the innominate vein and sewn end-to-end to the innominate artery with running 5-0 polypropylene (FIG 5). Next, the left common carotid artery is transected, and the proximal end of the carotid artery is oversewn with 4-0 polypropylene. The distal smaller end of the Y-graft is tunneled underneath the innominate vein and sewn P.4 end-to-end to the carotid artery with running 5-0 poly-propylene (FIG 6). At this point, a decision needs to be made regarding the debranching strategy for the left subclavian artery. Indications for left subclavian revascularization are controversial. Routine versus selective strategies may be adopted.7 If the left subclavian artery needs to be revascularized but cannot safely be exposed, a carotidsubclavian bypass can be performed as previously mentioned. If the subclavian artery can be exposed, the distal anastomosis is created first using a 6- or 8-mm Dacron graft anastomosed either end-to-end to the transected artery or end-to-side (functional end-to-end) followed by ligation of the proximal artery in continuity. A side-biting clamp is then placed along the carotid graft, and the subclavian graft is sutured end-to-side to the carotid graft with 5-0 polypropylene suture (FIG 7). Protamine is administered to reverse the heparin, and hemostasis is ensured. The grafts should lie tension free within the mediastinum. The pericardium may be partially closed over the grafts, with care to avoid compression of the graft branches. Chest tubes are positioned, and the sternum is closed routinely. After the sternum is closed, the blood pressure should be assessed in each arm and cerebral oximetry monitored to confirm adequate perfusion through the graft branches and the absence of graft compression. P.5

FIG 2 • After sternotomy, the pericardium is incised and retracted. The ascending aorta is mobilized, and the brachiocephalic arteries are circumferentially exposed. The innominate vein is mobilized and retracted with an umbilical tape to facilitate exposure of the arch vessels.

FIG 3 • A Y-graft is constructed by sewing a beveled smaller Dacron graft (6 to 8 mm) end-to-side to larger Dacron graft (10 to 12 mm).

FIG 4 • An aortic side-biting clamp is placed on the right anterolateral side (convexity) of the ascending aorta, as low as possible. The proximal end of the larger (10 or 12 mm) graft is beveled and sewn end-toside to the ascending aorta with a running 3-0 or 4-0 polypropylene suture.

FIG 5 • The innominate artery is transected, and the proximal end is oversewn 4-0 polypropylene. The distal large end of the Y-graft is then tunneled underneath the innominate vein and sewn end-to-end to the innominate artery with running 5-0 polypropylene.

FIG 6 • The left common carotid artery is transected, and the proximal end of the carotid artery is oversewn with 4-0 polypropylene. The distal smaller end of the Y-graft is tunneled underneath the innominate vein and sewn end-to-end to the carotid artery with running 5-0 polypropylene.

FIG 7 • If the subclavian artery can be exposed, the distal anastomosis is created first using a 6- or 8-mm Dacron graft anastomosed end-to-end to the transected artery. The subclavian graft is then sutured end-toside to the carotid graft with 5-0 polypropylene suture.

ENDOVASCULAR SECOND STAGE The endovascular second stage of the arch repair is conducted in a fairly similar manner to that of stent graft repair of a descending thoracic aortic aneurysm, as described in Chapter 13 (Thoracic Endografting). The timing of the endovascular repair as a single versus staged approach remains controversial. We prefer to delay the second stage depending on the clinical scenario. It can range from a few days (same hospitalization) to several weeks (separate admission) to allow the patient to recover from the first procedure. This reduces the overall physiologic stress on the patient. Although we favor delivery of the stent graft in a retrograde manner from the iliofemoral arteries, in cases

of a mechanical aortic valve or severe iliofemoral occlusive disease, single-stage antegrade deployment should be considered. The technical variations for these less common situations are beyond the scope of the present chapter. The site of insertion of the endovascular graft delivery system is decided based on the size and quality of the access vessels. In general, the grafts are delivered through the common femoral artery, whereas an iliac conduit may be required for very small or diseased iliofemoral arteries. The delivery guidewire is placed in the left ventricle during the endovascular procedure to provide sufficient proximal rail support for the endovascular graft. The proximal stent graft is deployed in the ascending aorta just distal to the origin of the debranching graft. During deployment, it is useful to lower the blood pressure using one of a variety of pharmacologic, ventricular pacing or atrial inflow occlusion techniques.8

PEARLS AND PITFALLS Indications

▪ The preoperative CT angiogram should be reviewed in detail to ensure the patient is a suitable candidate for aortic arch repair with debranching and stent grafting, including appropriate landing zones proximally and distally and adequate vascular access.

Proximal type I endoleak

▪ To optimize the length of the proximal landing zone and prevent a type I endoleak, the debranching graft should be placed as low as possible on the ascending aorta. Preemptive replacement of the ascending aorta should be performed if it is extremely short or its diameter is >34 mm.

Mechanical aortic prosthesis

▪ After aortic debranching, the endovascular graft delivery system may have to cross the aortic valve. Although transvalvular placement of a large sheath is relatively safe for native and bioprosthetic valves, it is contraindicated for a mechanical aortic valve. Antegrade stent graft deployment at the time of debranching should be considered in the presence of a mechanical prosthesis.

Injury to right coronary artery

▪ Care should be taken when applying the side-biting clamp low on the ascending aorta to avoid occlusion or injury to the right coronary artery.

Ascending aortic dissection

▪ The systolic blood pressure should be lowered to 98%), with excellent primary rates and low associated procedure morbidity.29 Percutaneous treatment of upper extremity traumatic arterial injuries of subclavian artery are associated with decreased operative time and intraoperative blood loss while maintaining equivalent patency rates to standard open repairs.30,31 Axillary artery branch vessel repair outcomes are met with high success rates of symptom resolution and lack of recurrence if distal emboli are lysed and proximal branch vessel embolic source is completely isolated from the circulation.14

COMPLICATIONS Intraoperative arterial vasospasm or occlusion Missed concomitant venous or nerve injuries during traumatic arterial injuries Iatrogenic brachial plexus, median, or ulnar nerve injuries from intraoperative electrocautery, traction, or accidental transection Iatrogenic injury to the brachial artery when attempting retrograde catheter embolization, especially when failing to take into account the significant taper present in the proximal brachial artery Arterial bypass graft stenosis or thrombosis Repair site bleeding Wound or graft site infection Digital or vertebral artery embolization, complicating thromboembolectomy Postrevascularization compartment syndrome in the arm or hand Stent failure when deployed in proximity to the clavicle/1st rib

REFERENCES 1. Valentine RJ, Wind GG. Axillary artery. In: Valentine RJ, Wind GG, eds. Anatomic Exposures in Vascular Surgery. Philadelphia, PA: Lippincott Williams & Wilkins; 2003:155-175. 2. Valentine RJ, Wind GG. Brachial artery. In: Valentine RJ, Wind GG, eds. Anatomic Exposures in Vascular Surgery. Philadelphia, PA: Lippincott Williams & Wilkins; 2003:177-188. 3. Stonebridge PA, Clason AE, Duncan AJ, et al. Acute ischaemia of the upper limb compared with acute lower limb ischaemia; a 5-year review. Br J Surg. 1989;76:515-516. 4. Ahn SS, Kudo T. Thoracic outlet syndrome and vascular disease of the upper extremity. In: Moore WS, ed. Vascular and Endovascular Surgery: A Comprehensive Review. Philadelphia, PA: Saunders Elsevier; 2006:675-693. 5. Yeager RA, Moneta GL, Edwards JM, et al. Relationship of hemodialysis access to finger gangrene in

patients with end-stage renal disease. J Vasc Surg. 2002;36:245-249. 6. Engelberger RP, Kucher N. Management of deep vein thrombosis of the upper extremity. Circulation. 2012;126:768-773. 7. Kucher N. Clinical practice. Deep-vein thrombosis of the upper extremities. N Engl J Med. 2011;364:861869. 8. Rutherford RB, Baker JD, Ernst C, et al. Recommended standards for reports dealing with lower extremity ischemia: revised version. J Vasc Surg. 1997;26:517-538. 9. Slauterbeck JR, Bitton C, Moneim MS, et al. Mangled extremity severity score: an accurate guide to treatment of the severely injured upper extremity. J Orthop Trauma. 1994;8:282-285. 10. Maksimowicz-McKinnon K, Hoffman GS. Large vessel vasculitis. Clin Exp Rheumatol . 2007;25:S58-S59. 11. Lazarides MK, Georgiadis GS, Papas TT, et al. Diagnostic criteria and treatment of Buerger’s disease: a review. Int J Low Extrem Wounds. 2006;5:89-95. 12. Schmidt WA, Wernicke D, Kiefer E, et al. Colour duplex sonography of finger arteries in vasculitis and in systemic sclerosis. Ann Rheum Dis. 2006;65:265-267. 13. Macik BG, Ortel TL. Clinical and laboratory evaluation of the hyper-coagulable states. Clin Chest Med. 1995;16:375-387. 14. Dalman RL, Olcott C. Upper extremity revascularization proximal to the wrist. Ann Vasc Surg. 1997;11:643-650. 15. Degiannis E, Levy RD, Sliwa K, et al. Penetrating injuries of the brachial artery. Injury. 1995;26:249-252. 16. Slowik GM, Fitzimmons M, Rayhack JM. Closed elbow dislocation and brachial artery damage. J Orthop Trauma. 1993;7: 558-561. 17. Tonnessen BH. Iatrogenic injury from vascular access and endovascular procedures. Perspect Vasc Surg Endovasc Ther. 2011;23: 128-135. 18. Machleder HI, Sweeney JP, Barker WF. Pulseless arm after brachialartery catheterisation. Lancet. 1972;1:407-409. 19. Rodriguez-Niedenfuhr M, Vazquez T, Nearn L, et al. Variations of the arterial pattern in the upper limb revisited: a morphological and statistical study, with a review of the literature. J Anat. 2001; 199:547-566. 20. Shaw AD, Milne AA, Christie J, et al. Vascular trauma of the upper limb and associated nerve injuries. Injury. 1995;26:515-518.

21. Fitridge RA, Raptis S, Miller JH, et al. Upper extremity arterial injuries: experience at the Royal Adelaide Hospital, 1969 to 1991. J Vasc Surg. 1994;20:941-946. 22. Zaraca F, Ponzoni A, Sbraga P, et al. Does routine completion angiogram during embolectomy for acute upper-limb ischemia improve outcomes? Ann Vasc Surg. 2012;26:1064-1070. 23. Gelberman RH, Garfin SR, Hergenroeder PT, et al. Compartment syndromes of the forearm: diagnosis and treatment. Clin Orthop Relat Res. 1981;(161):252-261. 24. Ko JH, Hanel DP. Technique of fasciotomy: hand. Tech in Orthop. 2012;27:38-42. 25. Guyatt GH, Akl EA, Crowther M, et al. Executive summary: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2012;141:7S-47S. P.90 26. Hughes K, Cubangbang M, Blackman K, et al. Upper extremity bypass for chronic ischemia—a national surgical quality improvement program study database study. Vasc Endovascular Surg. 2013;47:192-194. 27. Hughes K, Hamdan A, Schermerhorn M, et al. Bypass for chronic ischemia of the upper extremity: results in 20 patients. J Vasc Surg. 2007;46:303-307. 28. Licht PB, Balezantis T, Wolff B, et al. Long-term outcome following thromboembolectomy in the upper extremity. Eur J Vasc Endovasc Surg. 2004;28:508-512. 29. Patel SN, White CJ, Collins TJ, et al. Catheter-based treatment of the subclavian and innominate arteries. Catheter Cardiovasc Interv. 2008;71:963-968. 30. Carrafiello G, Lagana D, Mangini M, et al. Percutaneous treatment of traumatic upper-extremity arterial injuries: a single-center experience. J Vasc Interv Radiol . 2011;22:34-39. 31. Xenos ES, Freeman M, Stevens S, et al. Covered stents for injuries of subclavian and axillary arteries. J Vasc Surg. 2003;38: 451-454.

Chapter 11 Distal to the Wrist: Upper Extremity Revascularization and Reconstruction Michael G. Galvez James Chang

DEFINITION Arterial reconstruction and revascularization distal to the wrist requires reconstituting the complex vascular supply to the hand. This includes the ulnar and radial arteries, superficial and deep palmar arches, and common and proper digital arteries. This reconstitution is performed with either endtoend primary vascular repair, interposition vascular graft bypass with proximal and distal anastomoses, or addressing the digital arteries individually. Additionally, fasciotomy for compartment syndrome following trauma or reperfusion injury may be a necessary adjunct.

DIFFERENTIAL DIAGNOSIS/PRECIPITATING CAUSES OF HAND ISCHEMIA Arterial injury Traumatic (laceration, high energy or crush injury, etc.) or iatrogenic injury (including inadvertent or intentional cannulation for vascular access). Proximal embolization Intraluminal thrombosis Hypothenar hammer syndrome occurs when the base of the hypothenar eminence sustains repeated blunt trauma resulting in chronic injury to the distal ulnar artery and the superficial palmar arch. In this scenario, compression occurs between the roof of Guyon’s canal and the hook of the hamate bone, resulting in aneurysmal degeneration of the ulnar artery, luminal thrombus accumulation, and digital embolization (typically the ring and small finger). This typically occurs on the dominant hand of individuals participating in vocational or avocational activities involving repeated palmar impact (e.g., pipe fitters and mountain bike riders). Spontaneous radial artery thrombosis may be associated with Buerger’s disease and is not as common as ulnar artery thrombosis. Chronic digital ischemia secondary to vasospastic and rheumatologic disease: Primary Raynaud’s syndrome refers to cold-induced vasospasm present in the absence of concomitant disease. The etiology of this condition remains uncertain but is likely due to an exaggerated adrenergic receptor-mediated response to cold exposure. Secondary Raynaud’s syndrome refers to digital vasospasm which occurs in the setting of known autoimmune collagen vascular diseases and related rheumatologic disorders (such as rheumatoid arthritis). In this circumstance, a normal vasospastic response to cold or environmental stimuli is superimposed on chronic digital artery occlusive disease. Differentiation from primary Raynaud’s syndrome is most commonly made based on digital ulceration and tissue loss, conditions which uniformly develop in secondary

Raynaud’s syndrome. CREST syndrome encompasses the most common phenotypic presentation of systemic scleroderma/sclerosis: calcinosis, Raynaud’s phenomenon, esophageal stenosis, sclerodactyly, and associated telangiectasias. Buerger’s disease, or thromboangiitis obliterans, represents a progressive, recurring necrotizing arteritis of small and medium vessels closely linked to tobacco exposure. Compartment syndrome occurs in response to increased pressure within a fixed osteofascial anatomic space, leading to decreased arterial perfusion, irreversible myonecrosis, neuropathy, and potential limb loss. In the hand, compartment syndrome most commonly develops following crush injuries; however, intravenous infiltration, external compression, and other mechanisms may also induce increased compartment pressure.

PATIENT HISTORY AND PHYSICAL FINDINGS Determine the hand dominance of the patient and relevant history of trauma, tobacco use, medical history (coagulopathic disorders), and occupational exposures. Additionally, the presence of palpable masses, pain, sensory changes, or color changes should be evaluated. An Allen’s test may provide additional information regarding the relative contribution of the ulnar and radial arteries to hand perfusion. This test is performed by manual compression of both the radial and ulnar arteries, with elevation and successive opening and closing performed to drain venous blood from the hand. The time differential to reperfusion, following respective arterial release, provides qualitative insight into relative radial or ulnar dominance. In most cases, however, the ulnar artery is dominant, and modern quantitative arterial perfusion assessment by duplex imaging and digital plethysmography has largely supplanted subjective physical exam findings in the assessment of adequacy of arterial inflow. Patients with hypothenar hammer syndrome can have complaints of pain and tenderness of the hypothenar mass, with cold sensitivity and numbness of the ring and small finger secondary to digital embolization and direct ulnar nerve compression. A pulsatile mass may, on occasion, be appreciable in the palm. Discoloration of the lateral three fingers of the hand may also be present as a result of chronic digital embolization. Patients with spontaneous radial artery thrombosis present with pain, numbness, and discoloration of the tips of the P.92 radial-sided digits. The area of occlusion is commonly beneath the first and third extensor compartments and can be related to compression of the radial artery by the extensor pollicis longus.1 Patients with Raynaud’s syndrome report ischemic symptoms and digital discoloration on exposure to cold. Coldinduced vasospasm may be elicited by cold emersion testing in an ice bath. A positive test is elicited by the elimination of plethysmographic pulsatile phasicity on exposure to cold, in addition to the onset of symptoms. Most patients, however, cannot tolerate this provocative test, and the clinical use of eliciting vasospastic symptoms, particularly in the presence of existing digital ulceration, is uncertain. Compartment syndrome is a clinical diagnosis. Cardinal signs include persistent and progressive pain unrelieved with immobilization/elevation, tightness of skin, pain with passive extension, and decreased sensation. Reduced skin temperature, pallor, and pulselessness are often late findings. The intrinsic compartments are tested for pain with passive adduction and abduction of the fingers. The thenar compartment is tested by adduction of the thumb. The adductor of the thumb is tested by passive palmar abduction. The hypothenar compartment is tested by adduction of the small finger.

Normal intracompartment pressures are less than 10 mmHg; between 10 and 20 mmHg is considered high but not enough to cause muscle necrosis. An acute compartment syndrome is assumed if the measured interstitial tissue pressures are within 30 mmHg of the mean arterial pressure or 20 mmHg of the diastolic blood pressure.2 Hand pressures are typically difficult to assess on the basis of direct measurement, given the extensive septation of the fascial compartments, underscoring the importance of clinical diagnosis. When in doubt, it is prudent to proceed with operative fasciotomy.

IMAGING AND OTHER DIAGNOSTIC STUDIES As previously mentioned, noninvasive vascular imaging and physiologic assessment are essential to establishing the diagnosis of hand and digital ischemia as well as providing a physiologic corollary to subsequent arterial imaging studies obtained to outline the relevant anatomy. Noninvasive testing informs and should always precede anatomic imaging studies regardless of modality. Imaging provides essential identification of normal and variant arterial anatomy, recognition of the location and extent of obstructive and aneurysmal disease, and operative planning. The vascular anatomy of the hand includes the ulnar artery, radial artery, and sometimes a persistent median artery (5% of the population). The ulnar and radial arteries anastomose to form the superficial and deep palmar arches, with the ulnar artery being the main contributor to the superficial arch and the radial artery the main contributor to the deep palmar arch (FIG 1). There is significant variation in the vascular patterns of the superficial and deep palmar arches. The superficial palmar arch is completed by either the branches of the deep palmar arch, radial artery, or median artery in about 80% of patients. The deep palmar arch is completed by the superior branch of the ulnar artery, the inferior branch of the ulnar artery, or both in about 97% of patients. The main branches from the superficial palmar arch are the three common digital arteries, which go to the index-middle, middle-ring, and ring-small finger webspaces, as well as the proper digital artery to the ulnar aspect of the small finger. Each digit has a dual blood supply from the radial and ulnar proper digital vessels. The thumb has blood supply from the princeps pollicis artery, which variably arises from the radial artery, the deep palmar, or superficial palmar arch. Catheter-directed, contrast-enhanced, digital subtraction hand arteriography provides highly detailed anatomic information and represents the gold standard in vascular imaging (FIG 2). However, there are risks from this invasive procedure, which include contrast allergic reaction, vasospasm, contrast-induced nephropathy, thromboembolic events including digital embolization and stroke, and drug reactions precipitated by intraarterial injection of vasoactive agents including Priscoline and nitroglycerin. Hence, catheter-based arteriography is best suited to operative planning in patients already determined to need reconstructive surgery. P.93 Magnetic resonance arteriography (MRA) is another option for imaging that is noninvasive, eliminating risks of radiation, contrast reaction, and vasospasm. However, the resolution of MRA is not sufficient for detailed surgical planning. Computed tomographic arteriography (CTA) is also noninvasive, although contrast and (significant) radiation exposure are required for image acquisition. Similar to MRA imaging, the resolution of CTA is typically not sufficient to support detailed surgical planning. Measuring compartment pressures of the hand can be performed with the Stryker Intra-Compartmental Pressure Monitor (Kalamazoo, Michigan), which involves placing the device needle perpendicular to the skin

and evaluating individual compartments including sites of maximum swelling of the thenar, hypothenar, and interosseous compartments. The compartment being measured should be at the level of the heart. In an intensive care unit setting, using an arterial pressure line connected to a strain gauge, zeroed at the level of needle entry into the hand, can also provide rapid and accurate compartmental measurements. A 20-gauge needle is inserted into the compartment and flushed, with measurement acquired after the flush bolus has disseminated in the compartment and the pressure spike from the flush returns to baseline.

FIG 1 • Anatomy of the hand illustration: schematic drawing of the vascular supply of the hand, demonstrating the ulnar artery as it passes Guyon’s canal and becomes the superficial palmar arch, radial artery as it becomes the deep palmar arch, the common digital arteries, and the proper digital arteries.

FIG 2 • Hand angiogram: normal hand angiogram demonstrating complete superficial and deep palmar arches.

SURGICAL MANAGEMENT Preoperative Planning The overall goal is to restore distal blood flow to baseline/maximal levels, given anatomic constraints, available arterial conduit, central arterial perfusion pressure and cardiac output, and end-organ (hand) viability. Treatment of thromboembolic disease can include medical management and catheter-based chemical and mechanical thrombolysis, angioplasty, and stenting to maximize arteriolar outflow and arterial inflow, respectively. Upper extremity revascularization techniques are discussed in Chapter 10. End-to-end primary vascular repair can be performed if arteries are tension free after mobilization, and the zone of injury is accurately identified to be uninvolved in the site of anastomosis. If there is any difficulty in approximating the vessels ends, then vascular grafts are preferred. In ulnar or radial artery thrombosis, reconstruction is preferred over ligation. Proximal reconstructions are attempted even in the setting of more distal occlusions, based on the rationale of augmenting collateral flow via direct or indirect means.3 Determining venous or arterial graft harvest site is important for preoperative planning. Dorsal hand or foot veins provide the most appropriate size match for intrinsic arteries of the hand (and feet). Donor sites for arterial graft conduits include the deep inferior epigastric artery, subscapular artery, thoracodorsal artery, or descending branch of the lateral femoral circumflex artery. Typically, arterial grafts patency rates are superior to those obtained with venous grafts.4 For chronic ischemia, medical management including pharmacologic treatment with vasodilators, topical nitroglycerin, calcium channel blockers, or botulinum toxin should be attempted first, prior to surgical management.5 Evidence of gangrene, osteomyelitis, and so forth of the involved digit may require debridement or digital amputation.

Periarterial sympathectomy in the hand, which involves stripping the adventitial layers from affected arteries, removes sympathetic nerve input to the media and has proven effective in promoting distal finger lesion healing in scleroderma patients. In scleroderma specifically, the thickened adventitia apparently contributes to decreased digital arterial flow.6,7

Positioning Hand surgery is usually performed with the patient in the supine position. The operated hand is placed on a hand surgery table, which is stabilized by two legs. Reconstructive surgery may be performed under tourniquet, depending on systemic comorbidities and the adequacy of arterial inflow. For tourniquet control, the upper arm is well padded with Webril (cotton) wrapped circumferentially, and then an 18-in (or appropriately sized) pneumatic tourniquet is secured around the upper arm (FIG 3). Alternatively, depending on inflow status, the tourniquet may be placed at the forearm or wrist. Finally, an impervious barrier (3M SteriDrape 1000) is placed circumferentially just distal to the tourniquet to prevent see page of the sterile prep solution. The arm/hand are then sterilely prepped and draped. Intraoperatively, the arm is exsanguinated with an elastic bandage (Esmarch bandage) wrap and elevation immediately prior to tourniquet inflation. In adults, the tourniquet is typically inflated to 250 mmHg; in children, it is set 100 mmHg above the systolic pressure. The tourniquet inflation should last no more P.94 than 2 hours and must be deflated for a 20-minute interval to allow reperfusion prior to reinflation, if needed. Consideration should be made to establishing systemic anticoagulation prior to tourniquet inflation when indicated. Appropriate concurrent sterile prep should be performed on graft harvest sites as necessary. Microsurgery prep includes ensuring that the operating scope is working properly and sterilely draped. Positioning is extremely important to reduce surgeon fatigue, which includes ensuring good table height, working height (with appropriate padding support of the wrists with stacks of surgical towels), and sitting position. Microsurgery instruments should be available as necessary, depending on the level of revascularization considered. 9-0 and 10-0 sutures are employed for more distal reconstructive procedures and digital reimplantation. For proximal radial and ulnar reconstruction procedures, at or immediately adjacent to the wrist, 2.5 × to 3.5 × surgical loupe magnification will provide adequate anatomic resolution and suture placement for operators with normal visual acuity.

FIG 3 • Positioning illustration: supine positioning of patient with arm being operated on placed out on hand table. Webril gauze is wrapped circumferentially around the arm and followed by tourniquet placement. Appropriate tourniquet pressure is set. Finally (not pictured) a 3M Steri-Drape 1000 is wrapped circumferentially.

ULNAR ARTERY RECONSTRUCTION Placement of Incision Identify the ulnar artery aneurysm (FIG 4A), and incise the skin longitudinally over the ulnar artery as it crosses Guyon’s canal. Extension across the midpalmar crease may be necessary to expose the distal ulnar artery as it curves radially to become the superficial palmar arch. The volar carpal ligament, the roof of Guyon’s canal, is a continuation of the deep palmar fascia and fibers of the flexor carpi ulnaris and must be carefully incised for access to the ulnar artery and nerve. The ulnar nerve, particularly the motor branch, must be carefully protected.

Resection of Ulnar Aneurysm

Once the deep palmar fascia is incised, the aneurysm is generally recognizable (FIG 4B AND FIG 5A). The aneurysm itself may be thrombosed or tortuous or elongated as a result of chronic posttraumatic remodeling. Microvascular clamps are placed on the ulnar artery proximal and distal to the aneurysm. Preserve the common digital arteries and other large branches distal to the thrombosed segment. Place microvascular clamps and vessel loops as needed on vessels that will require revascularization. Resect the affected artery and trim the ends sharply. The adventitia is excised as needed, and the intima inspected at the proximal and distal end of the anastomoses to ensure P.95 that the entire disease segment is removed. Failure to remove the entirety of diseased artery may precipitate early graft thrombosis and recurrent digital embolization.

FIG 4 • Ulnar artery reconstruction: A. Hand angiogram demonstrating a large ulnar artery aneurysm in Guyon’s canal. B. Ulnar aneurysm segment is isolated proximally and distally. C. A direct end-to-end anastomoses was performed. D. In another patient, a long vein graft is used to extend from a more proximal ulnar artery.

Vein Graft Interposition Occasionally, sufficient redundancy is present in the ulnar artery to allow direct primary repair (FIG 4C); in most cases, interposition vein grafting (FIG 4D) is required to complete the reconstruction without tension. When the superficial palmar arch and adjacent common digital arteries are involved, then a more complex “palmar arch” reconstruction may be necessary to restore perfusion to the dependant digits (FIG 5B), with end-toside anastomoses of the common digital arteries into the distal extent of the vein graft. Vein harvest is typically chosen from the hand and foot veins. Length of vein harvest should be several

centimeters longer to allow for trimming. Marking the superficial surface of the vein helps avoid twisting or kinking of the vein graft. Marking one end (typically distal) provides a reminder to reverse the graft prior to implantation. If needed, ends with valves are excised. Arterial graft may also be used when available and of suitable diameter and length. Longer grafts may also be used (FIG 4D) when more proximal arterial inflow is required. Microvascular anastomosis of vessel graft. Anastomosis completion may require microsurgical technique, given that common digital arteries may be 1 to 2 mm in diameter. Both ends of the vessels are held in place by an appropriately tensioned microvascular double-armed clamp. After irrigation with heparinized saline, interrupted sutures are placed circumferentially using a triangulation technique. The proximal anastomosis is performed first, then flushed with heparin and clamped to allow the vein graft to extend to length before preparing and completing the distal anastomos(e)s.

FIG 5 • Ulnar artery reconstruction illustration. Exploration of the ulnar artery confirms findings of angiogram demonstrating (A) ulnar artery thrombosis to the origin of the common digital arteries. Reconstruction requires harvesting a Y branch of a saphenous vein graft, which is then reversed prior to interposition. B. End-to-side distal anastomosis, endtoend anastomosis of the vein branch to the common digital artery, and end-to-side anastomosis to common digital artery are performed.

SNUFFBOX RADIAL ARTERY RECONSTRUCTION Placement of Incision

At the level of wrist, the radial artery turns dorsally underneath the first extensor compartment (containing the abductor pollicis longus and extensor pollicis brevis), then runs between the first and third extensor compartments (extensor pollicis longus) in the area known as the “anatomic snuffbox.” The diseased segment and distal targets should be confirmed by reference to the specific preoperative imaging studies (FIG 6A,B). A skin incision is made on the dorsum of the hand directly over the anatomic snuffbox parallel to the second metacarpal (FIG 7A). The superficial radial nerve is identified and preserved.

FIG 6 • Snuffbox radial artery reconstruction angiograms: A,B. Angiograms demonstrating cutoff of radial artery (arrow demonstrates filling defect corresponding to occluded segment) at the level of the anatomic snuffbox. P.96

FIG 7 • Snuffbox radial artery reconstruction: A. Incision over the radial artery over the anatomic snuffbox with micro background placed under artery. B. Radial artery is clamped distally. C. Vessel is clamped proximally and isolated with vessel loops prior to vein grafting.

Resection/Bypass of Diseased Segment This dissection is continued distally between the heads of the first dorsal interosseous muscle, allowing further mobilization of the distal radial artery and visualization of the origin of the deep palmar arch. Microvascular clamps are placed proximal and distal to the thrombosed segment of the radial artery. All branches from the thrombosed segment should be ligated and removed en bloc (FIG 7B).

Vein Graft Interposition The vein graft should be reversed and placed superficial to the extensor pollicis longus and extensor pollicis brevis (making the graft immediately beneath the skin) and then sutured end-to-end to the radial artery proximally and end-to-end to the deep arch distally (FIG 7C). See the “Ulnar Artery Reconstruction” section for further description on vein harvest and microvascular anastomosis technique.

HAND FASCIOTOMY Placement of Incisions The 10 compartments of the hand include the thenar, hypothenar, adductor, and 4 dorsal and 3 volar interossei compartments. Four incisions are required to release all 10 compartments. The dorsal and volar interosseous compartments are decompressed with two dorsal incisions over the index finger and ring finger metacarpal (FIG 8A). These incisions are carried down to either side of the metacarpal to release the dorsal interossei. Dissection along the ulnar and radial aspects of the index metacarpal must be sufficiently deep (FIG 8C) to release the first dorsal palmar interosseous and the adductor compartments. Similarly, to release the remaining palmar interossei, deep dissection is required along the ulnar and radial aspects of the ring metacarpal. Meticulous release along the length of the metacarpal is essential to ensure adequate decompression. The thenar compartment is bound by thenar fascia and contains the abductor pollicis brevis, flexor pollicis brevis, and the opponens pollicis. This compartment is decompressed with a longitudinal incision along the radial/volar (FIG 8A) aspect of the thumb metacarpal. P.97 The hypothenar compartment is bound by the hypothenar fascia and contains the abductor digiti minimi, flexor digiti minimi, and opponens digiti minimi. This compartment is decompressed with a longitudinal incision along the ulnar/volar (FIG 8B) aspect of the small metacarpal. The finger can also have compartment syndrome if there is excessive swelling and depending on clinical assessment. Here, the fascial compartments are bound by Cleland’s and Grayson’s ligaments. The finger fasciotomy is performed by making midaxial incisions along the ulnar aspect of the index, ring, and long fingers and on the radial aspects of the thumb and small finger. Once incisions are made, blunt dissection is continued through Cleland’s ligament (firm fascia bands that run from side of the phalanges to the skin and are dorsal to the neurovascular bundle), retracting the neurovascular bundles in a volar direction and remaining volar to the flexor tendon sheath.

FIG 8 • Hand fasciotomy illustration: fasciotomy incisions of the hand. A. Dorsal incisions over the index (c) and ring (b) finger metacarpal. B. Volar incisions over the hypothenar (d) and thenar (a) muscles. C. Cross section at the level of the metacarpals of the hand demonstrating that both dorsal and interosseous compartments and the adductor compartment to the thumb can be released through these four incisions with appropriate direction and depth as outlined (a-d).

Carpal Tunnel Release If any compartment pressure is elevated in the hand, then all compartments should be released including the carpal tunnel. A longitudinal palmar incision is made just distal to the volar wrist crease and extending distally for 3 to 4 cm in the proximal palm along the course of the radial aspect of the ring finger. The palmaris fascia is divided longitudinally to expose the underlying transverse carpal ligament, which is then incised under direct visualization. The incision is extended at least 2 cm into the forearm to ensure release of the deep antebrachial fascia. The carpal tunnel release incision is closed primarily with interrupted nylon sutures.

Wound Care Fasciotomy wounds are left open for a minimum of 48 hours or until swelling has resolved. Secondary closure with wet-to-dry dressings may occur over open incisions. Eventually, these wounds may need split-thickness skin grafting. The hand should be splinted in a safe position (70 to 90 degrees of metacarpophalangeal [MCP] flexion and proximal interphalangeal [PIP] joints straight).

PEARLS AND PITFALLS ▪ Although a thrombosed ulnar artery can be ligated, reconstruction of the ulnar artery can reconstitute normal flow and should be attempted. ▪ Hand vascular repair and grafting requires meticulous microvascular technique. ▪ The dorsal sides of the hand and foot have veins of similar size that are ideal for vein graft reconstruction. ▪ Periarterial sympathectomy is particularly effective in scleroderma because the vessels are encased in adventitial scarring. ▪ Early diagnosis and treatment for hand compartment syndrome is critical: When in doubt, release all compartments.

POSTOPERATIVE CARE Postoperative monitoring of the hand after vascular reconstruction is similar to finger replantations and can be performed with pencil Doppler monitoring or with pulse oximetry (FIG 9). Aspirin 81 mg is given for 6 weeks postoperatively after vessel reconstruction. For periarterial sympathectomy, immediate digital range of motion is encouraged, and cold temperature and vasoconstrictive drugs or substances (smoking, caffeine, etc.) are avoided for at least 6 weeks. For compartment syndrome, aggressive strengthening and range of motion should be started once wounds have stabilized.

OUTCOMES Radial artery reconstruction patency in a study of 13 patients found that all vein grafts were patent after mean follow-up of 22 months, with a significant decrease in pain; however, no difference in numbness was seen.3 In another study of 145 patients, an overall patency of vein grafts of 85% over P.98 an average follow-up period of 34 months was found as well as 100% with arterial grafts.4 Long-term recovery after compartment syndrome release depends on the extent of injury and requires long-term hand therapy for recovery of hand function. Compartment release of the hand can result in normal function; however, contractures can develop, which may need eventual reoperation for contracture release.

FIG 9 • Hand postoperative monitoring: Revascularization of digits can be monitored with basic pulse oximetry at the tip of the digits.

COMPLICATIONS Infection Dehiscence of incisions and other wound healing complications Failure of revascularization Distal emboli Thrombosis at anastomosis Long-term patency Stiffness of the fingers Continued ischemia, pain, and ulcerations

REFERENCES 1. Pomahac B, Hagan R, Blazar P, et al. Spontaneous thrombosis of the radial artery at the wrist level. Plast Reconstr Surg. 2004;114(4):943-946. 2. Leversedge FJ, Moore TJ, Peterson BC, et al. Compartment syndrome of the upper extremity. J Hand Surg Am. 2011;36(3):544-559. 3. Ruch DS, Aldridge M, Holden M, et al. Arterial reconstruction for radial artery occlusion. J Hand Surg Am. 2000;25(2):282-290. 4. Masden DL, Seruya M, Higgins JP. A systematic review of the outcomes of distal upper extremity bypass surgery with arterial and venous conduits. J Hand Surg Am. 2012;37(11):2362-2367. 5. Porter SB, Murray PM. Raynaud phenomenon. J Hand Surg Am. 2013;38(2):375-377. doi:10.1016/j.jhsa.2012.08.035. 6. Hartzell TL, Makhni EC, Sampson C. Long-term results of periarterial sympathectomy. J Hand Surg Am. 2009;34(8):1454-1460. 7. Bogoch ER, Gross DK. Surgery of the hand in patients with systemic sclerosis: outcomes and considerations. J Rheumatol . 2005;32(4):642-648.

Chapter 12 Exposure and Open Surgical Reconstruction in the Chest: The Thoracoabdominal Aorta Germano Melissano Efrem Civilini Enrico Rinaldi Roberto Chiesa

DEFINITION A thoracoabdominal aortic aneurysm (TAAA) involves the aorta at the diaphragmatic crura and extends variable distances proximally and/or distally from this point (FIG 1).1 TAAAs can be classified in terms of their causes, the two most common being medial degeneration and dissection. Open treatment of TAAAs consists of graft replacement with reattachment of the main aortic branches: The inclusion technique was introduced by S. E. Crawford in the 70s and refined by subsequent surgeons in the following decades. TAAA repair, especially in extensive aortic disease, is associated with greater operative risk than repair of other aortic segments. The main sources of morbidity are spinal cord (SC) ischemia and renal as well as respiratory and cardiac complications. Experienced surgical centers now report lower mortality and morbidity rates for TAAA repair,2 largely due to multimodal approaches to reduce surgical trauma and maximize organ protection.3

IMAGING AND OTHER DIAGNOSTIC STUDIES To plan the best possible treatment strategy for each patient, our preferred modality is computed tomographic arteriography (CTA). The acquisition of computed tomography (CT) data in particular has benefited from spectacular progress, including multirow detectors, higher rotation and translation speeds with reduced scan times (single breath-hold), cardiac cycle synchronization, and better postprocessing capabilities. Digital Imaging and Communications in Medicine (DICOM) slices of adequate thickness (≤1 mm) should be postprocessed on a digital workstation using a multiplanar reformatting (MPR) tool to visualize a scan which angulation matches that of the aorta or the vessel under investigation. Postprocessing may be performed on a dedicated workstation (AquariusNet®, TeraRecon, Inc) or desktop computer with open source software (OsiriX and others) in a user-friendly and time/resources-efficient way (FIG 2). Beyond analysis of aortic diameter and the extent of pathologic involvement, reformatted images are particularly useful for evaluating the presence, extension, and characteristics of dissection and thrombus, particularly at proposed sites of clamp placement and the infradiaphragmatic aorta when direct aneurysm cannulation is considered for distal aortic perfusion. The exact location and geometry of aortic branches is obtained to reveal possible anatomic variations or anomalies, which are particularly common at the level of the renal arteries and arch vessels. Vessel patency is also routinely evaluated; in particular, obstruction of the superior and inferior mesenteric artery and the hypogastric arteries and dominance of one vertebral artery are assessed. Three-dimensional rendering tools such as maximum intensity projection (MIP), volume rendering, surface rendering, and so forth produce realistic imaging of the anatomic structures that may expand anatomic

understanding, including, for instance, the most appropriate intercostal space to perform thoracotomy (FIG 3). Perioperative SC ischemia may precipitate paraparesis or paraplegia. Prior knowledge of the SC arterial supply informs both procedural planning and risk stratification. P.100 Recent advances in imaging techniques, especially noninvasive techniques, increased the likelihood that patientspecific risk criteria may soon be recognized and be widely available4 ( FIG 4).

FIG 1 • An aneurysm is defined as thoracoabdominal when the highlighted region is involved. Crawford’s classification was developed to improve stratification of perioperative paraplegia risk. Subclassifications include the following: Extent I includes the thoracic and abdominal aorta, from the left subclavian artery to the level of the renal arteries; extent II includes the entire descending aorta from the level of the left subclavian artery to the aortic bifurcation; extent III includes aorta beginning at the T6 level extending to the bifurcation or lower; extent IV includes the entire abdominal aorta starting at the level of the diaphragm (T12) to the aortic bifurcation or lower.

FIG 2 • MPR tools allow the sagittal reconstruction to properly follow the major axis of the thoracic aorta. In this reformatted image, the entire thoracic aorta is included despite significant tortuosity.

FIG 3 • Beyond aortic imaging, the CT provides extensive anatomic information to guide exposure and surgical decision making.

SURGICAL MANAGEMENT Preoperative Workup and Patient Optimization Preoperative transthoracic echocardiography is a satisfactory noninvasive screening method to evaluate both

valvular and biventricular function. Stress testing identifies patients who require coronary catheterization and possible intervention. 5 Electrocardiographically (EKG) gated CT has recently emerged as a less invasive method of visualizing coronary anatomy. For severe, symptomatic coronary disease requiring percutaneous transluminal angioplasty prior to aneurysm repair, use of drug-eluting stents requiring prolonged double antiplatelet therapy should be avoided to reduce subsequent perioperative bleeding. The use of estimated glomerular filtration rate (eGFR), rather than serum creatinine levels alone, is recommended to assess renal function.6 Based on the eGFR metric, chronic kidney disease has been shown to be a strong predictor of death following open or endovascular thoracic aneurysm repair, even in patients without other clinical evidence of preoperative renal disease.7 Pulmonary function evaluation with arterial blood gases and spirometry is used to evaluate the respiratory reserve of all patients undergoing open surgery of the descending aorta. In patients with a forced expiratory volume in 1 second (FEV1) of less than 1 L and a partial pressure of carbon dioxide (PCO2) greater than 45 mmHg, operative risk may be improved by cessation of cigarette smoking, treatment of chronic bronchitis (if present), weight loss, and participation in a supervised exercise program for a period of up to 6 months prior to surgery. However, in patients with aneurysm-related symptoms, this type of respiratory rehabilitation may not be practical or possible.

FIG 4 • Using a customized curve plan, the whole path of the arterial feeder to the spinal cord (arteria radicularis magna) can be visualized from the aorta to the anterior spinal artery.

FIG 5 • Once the dura has been punctured with the introducer needle, a drainage catheter is inserted 8 to 10 cm along the intradural space. The catheter is then connected to a pressure transducer, and the fluid is drained to keep the pressure below 10 cm H2O. Automated systems are available for this purpose.

Positioning After inserting a cerebrospinal fluid drainage (CSFD)8 catheter into the subarachnoid space between L2 and L3 or L3 and L4 (FIG 5), the patient is turned to a right lateral decubitus position, with the shoulders at 60 degrees and the hips flexed back to 30 degrees. Preparation should allow for access to the entire left thorax, abdomen, and both inguinal regions. Patient position is maintained with a moldable beanbag attached to a suction line for vacuum creation. A circulating water mattress is placed between the beanbag and the patient in order to modify body temperature as necessary (FIG 6).

FIG 6 • Prepping and draping for TAAA. Posterolateral aspect of the left thorax, the abdomen, and left groin are included in the sterile operatory field. Please note the gentle curvature of the line indicating the skin incision to avoid flap necrosis.

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THORACO-PHRENO-LAPAROTOMY The thoracic incision varies in length and level, depending on exposure requirements. Usually, the 5th, 6th, or 7th intercostal space is employed according to the aneurysm anatomy. The posterior section of the ribs is gently spread to reduce thoracic wall trauma and fractures; anterolaterally, the incision curves gently as it crosses the costal margin to minimize subsequent tissue necrosis. The pleural space is entered after single right lung ventilation is initiated. Monopulmonary ventilation is maintained throughout thoracic aorta replacement (FIG 7). Paralysis of the left hemidiaphragm contributes significantly to postoperative respiratory failure; therefore, a limited circumferential rather than radial section of the diaphragm is routinely performed, sparing the phrenic center. Under favorable anatomic conditions, this approach reduces respiratory weaning time9 (FIG 8). Special care must be taken when isolating the proximal aneurysm neck. The insertion of a large caliber esophageal probe makes it easier to distinguish the esophagus at this level. The vagus nerve and the origin of the recurrent laryngeal nerve must also be identified because they can also be damaged during isolation and clamping maneuvers (FIG 9). Identification and clipping of some “high” intercostal arteries can sometimes facilitate the preparation for the proximal anastomosis, thus reducing aortic bleeding. The upper abdominal aortic segment is exposed via a transperitoneal approach; after entering the peritoneum, medial visceral rotation is performed to retract the left colon, spleen, and left kidney anteriorly and to the right (FIG 10). Use of a transperitoneal approach allows direct assessment of the abdominal organs at the end of procedure. Extra care must be taken to avoid damage to the spleen, which is particularly prone to bleeding after capsular injuries regardless of size.

FIG 7 • Thoraco-phreno-laparotomy in the 6th intercostal space. A circumferential incision of the diaphragm is carried out (dotted line).

FIG 8 • The diaphragm is circumferentially divided (arrows) for several centimeters near its peripheral attachment to the anterior chest wall sparing the phrenic center (asterisk).

FIG 9 • The vagus nerve (black arrow) and the origin of the recurrent laryngeal nerve are mobilized and

identified with vessel loops to prevent injury during aortic clamping maneuvers or suture placement. When an aortic crossclamping between left carotid and subclavian artery is required, these vessels are also identified and controlled with vessel loops (white arrows).

FIG 10 • Medial visceral rotation: The left colon, the spleen, and the left kidney are retracted anteriorly and to the right to visualize the visceral and infrarenal aorta. Transperitoneal approach allows direct evaluation of the abdominal organs throughout the procedure.

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DISTAL AORTIC PERFUSION Cross-clamping of the descending thoracic aorta produces immediate and significant increases in left ventricular afterload, myocardial oxygen consumption, and visceral and renal ischemia. Techniques incorporating distal aortic perfusion with left heart bypass (LHBP) have significantly improved outcomes in thoracic aortic surgery.10 In preparation for LHBP and aortic cross-clamping, lowdose intravenous heparin is administered. If cessation of pump support is anticipated during the case, additional heparin should be administered at that time to provide full anticoagulation. The upper left pulmonary vein is usually cannulated for inflow of oxygenated blood, which is routed through a centrifugal pump (Bio-Medicus®) into the left femoral artery (FIG 11). A “Y” connector included in the circuit provides two occlusion/perfusion catheters (9 Fr) for selective visceral perfusion when necessary.

FIG 11 • Schematic view of distal aortic perfusion. A 20-Fr cannula is inserted in left superior pulmonary vein for the arterial blood drainage (up). Nonocclusive femoral cannula (14 to 18 Fr) allows synchronous proximal and distal perfusion from the femoral axis (down).

AORTIC REPAIR Once the neck of the TAAA is isolated and controlled between clamps, the descending thoracic aorta is transected and separated from the esophagus (FIG 12). The graft is sutured proximally to the descending thoracic aorta using 2-0 polypropylene suture in a running fashion. The anastomosis is reinforced with Teflon felt (individual pledgets or single strip) (FIG 13). An additional aortic clamp is applied onto the abdominal aorta above the celiac axis before the proximal aortic clamp is removed (sequential crossclamping). Intercostal artery reimplantation into the aortic graft plays a critical role in SC protection. Patent intercostal arteries from T7 to L2 are temporarily occluded to prevent backbleeding/maximize cord perfusion pressure11 then selectively reattached to the graft by means of aortic patch or graft interposition ( FIG 14). When ready, the distal clamp P.103

is moved below the renal arteries, and the aneurysm is opened across the diaphragm. The centrifugal pump maintains visceral perfusion (400 mL per minute) following insertion of the 9-Fr irrigation-perfusion catheters (LeMaitre Vascular) into the celiac trunk and the superior mesenteric artery. Cold perfusion of Custodiol12 (histidinetryptophaneketoglutarate) is directed into the renal arteries ( FIG 15). For visceral artery reimplantation, a fenestration is created in the graft and the visceral vessels are reattached as a single patch. Usually, the left renal artery is reconnected with an 8-mm polyester interposition graft. If visceral artery orificial stenosis is encountered, before placing the irrigation perfusion catheter, the stenosis may be resolved by direct placement of an appropriate-sized balloon-expandable stent within the artery13 ( FIGS 16 and 17). If creation of the visceral patch requires retaining a large segment of native aorta, we prefer to place a multibranched graft instead. This prosthesis, although somewhat more time consuming, significantly reduces the risk of recurrent aortic patch aneurysm ( FIG 18). Finally, the distal end-to-end anastomosis with the distal aorta is performed, the graft flushed, and clamps removed ( FIG 19).

FIG 12 • The proximal descending thoracic aorta is controlled and completely transected to avoid accidental injury to the adjacent esophagus.

FIG 13 • The proximal anastomosis routinely reinforced with a Teflon strip.

FIG 14 • Critical intercostal arteries reattachment. Here visualized are two different techniques: On the left, an aortic island including the origin of several intercostal arteries is reattached to a fenestration created on the aortic graft; on the right, intercostal arteries are reattached selectively to the graft via 6/8-mm interposition grafts.

FIG 15 • Visceral arteries perfusion with blood, renal perfusion with cold Custodiol® solution during branch artery reimplantation.

FIG 16 • From left to right. In case of orificial stenosis, intraluminal stents are placed under direct visualization before insertion of the perfusion catheter and ultimate reimplantation.

FIG 17 • A modified technique to separately reattach the left renal artery is detailed here: The use of a hybrid tube graft that includes a self-expandable covered stent allows for a sutureless anastomosis. The advantages are the reduced ischemia time of the kidney and kink prevention of the graft after visceral derotation at the end of the aortic repair.

FIG 18 • Visceral vessels and renal arteries are reattached separately in this patient with Marfan syndrome to reduce as much as possible the aortic native tissue and prevent recurrent aortic aneurysm formation.

FIG 19 • End-to-end distal anastomosis at the aortic bifurcation.

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CLOSURE The entire aortic repair (FIG 20) is inspected. All exposed aortic branch pulses are palpated after derotation and replacement of the abdominal viscera. Any bleeding or kinking of the aortic branches is addressed at this juncture. The atrial and femoral cannulae are removed; the purse-string sutures are tied and reinforced. Anticoagulation is reversed with protamine. The crus of the diaphragm is reapproximated to restore the aortic hiatus (FIG 21) and the left hemidiaphragm loosely sutured with a running polypropylene suture. The left lung is temporarily inflated to check for air leakage. A closed-suction abdominal drain is placed next to the aortic graft in the left retroperitoneal space, and two chest tubes are placed in the posteroapical and basal pleural space. Absorbable pericostal sutures are placed to approximate the ribs (FIG 22), and two steel wires are used to stabilize the costal margin. The lung is inflated, and the correct expansion of all the segments is carefully checked; the pericostal and diaphragmatic sutures are tightened and ligated. The steel wires are twisted and buried in the cartilaginous costal margin. The abdominal fascia is closed with a running suture. The abdominal and thoracic drains are connected to suction. The serratus and latissimus dorsi muscles are approximated with separate absorbable sutures. Subdermal layer is sutured, and the skin is closed with staples (FIG 23).

FIG 20 • Final repair of a type II TAAA. A. Standard inclusion technique. B. Selective reimplantation with multibranched graft.

FIG 21 • The pillars of the diaphragm (arrows) are approximated with absorbable sutures to reshape the aortic hiatus.

FIG 22 • The thoracic wall is repaired with pericostal sutures. The left lung is inflated and checked for air leakage; two chest tubes are positioned to drain the upper and lower thoracic space.

FIG 23 • The abdominal and thoracic walls are sutured; skin is closed with staples.

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PEARLS AND PITFALLS Indications

▪ Aortic diameter and aneurysm morphology ▪ Signs and symptoms of acute aortic syndrome

Preoperative planning

▪ Level of intercostal incision ▪ Graft selection ▪ Identification of accessory renal arteries and other visceral anomalies (e.g., horseshoe kidney) ▪ Potential need for multibranch graft vs. Carrel patch

Surgical access

▪ Avoid skin flap necrosis. ▪ Rib section ▪ Limited phrenotomy (circumferential diaphragmatic incision) ▪ Transperitoneal approach ▪ Careful and limited lung manipulation ▪ Nonocclusive femoral cannulation

Technical adjuncts for organ protection

▪ Spinal cord drainage ▪ Left heart bypass ▪ Sequential aortic clamping ▪ Critical intercostal artery reattachment ▪ Visceral perfusion from left heart bypass cannulas ▪ Renal perfusion with cold Custodiol® or similar solution ▪ Direct stenting of renal and visceral orificial lesions as needed

POSTOPERATIVE CARE The main focus of immediate postoperative management is the early detection of neurologic or cardiovascular complication as prompt intervention may prevent substantial longterm morbidity. As soon as baseline blood pressure and body temperature are restored, sedation is lightened regardless of ventilatory status. When SC or cerebral neurologic injury is suspected, CT imaging is performed immediately to address the possibility of intracranial or intradural SC hematoma. In case of paraparesis or paraplegia, mean arterial pressure is chemically maintained above 80 mmHg, CSFD is drained in order to lower the cerebrospinal fluid pressure below 10 mmHg, and methylprednisolone (1 g bolus followed by 4 g per 24 hours continuous infusion) and 18% mannitol (5 mg/kg, four times a day) are administrated. If malperfusion develops in the lower limbs, renal or visceral circulation, efforts should be made to restore normal circulation immediately. For a precise visualization of visceral organ perfusion, emergency arteriography (catheter-based or CT) is required. Blood pressure fluctuations, including recalcitrant hypertension, is common in the early postoperative period, especially in the chronically hypertensive patient; prompt attention should be paid to regulating the mean arterial pressure in a physiologic range. Immediate intervention may be required to reduce the risk of anastomotic bleeding, especially in the setting of dissection. In uncomplicated cases, drainage tubes are removed at 36 to 48 hours postoperatively, whereas the intrathecal CSFD catheter is removed usually after 72 hours. A prolonged requirement for ventilatory support is not unusual, especially after emergency operations, in patients with significant blood loss and after longer periods of circulatory arrest (if necessary for concurrent arch or ascending aortic reconstruction). In case of severe chronic kidney disease, transient temporary renal replacement therapy may also be necessary in the early postoperative period.

COMPLICATIONS Bleeding Multiorgan failure Dialysis Paraplegia Stroke Death Aneurysm recurrence

REFERENCES 1. Johnston KW, Rutherford RB, Tilson MD, et al. Suggested standards for reporting on arterial aneurysms. Subcommittee on Reporting Standards for Arterial Aneurysms, Ad Hoc Committee on Reporting Standards, Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery. J Vasc Surg. 1991;13:452-458. 2. Coselli JS, Bozinovski J, LeMaire SA. Open surgical repair of 2286 thoracoabdominal aortic aneurysms. Ann Thorac Surg. 2007;83:S862-S864.

3. MacArthur RG, Carter SA, Coselli JS, et al. Organ protection during thoracoabdominal aortic surgery: rationale for a multimodality approach. Semin Cardiothorac Vasc Anesth. 2005;9:143-149. 4. Melissano G, Civilini E, Bertoglio L, et al. Angio-CT imaging of the spinal cord vascularisation: a pictorial essay. Eur J Vasc Endovasc Surg. 2010;39:436-440. 5. Kieffer E, Chiche L, Baron JF, et al. Coronary and carotid artery disease in patients with degenerative aneurysm of the descending thoracic or thoracoabdominal aorta: prevalence and impact on operative mortality. Ann Vasc Surg. 2002;16:679-684. 6. Stevens LA, Coresh J, Greene T, et al. Assessing kidney function— measured and estimated glomerular filtration rate. N Engl J Med. 2006;354:2473-2483. 7. Mills JL Sr, Duong ST, Leon LR Jr, et al. Comparison of the effects of open and endovascular aortic aneurysm repair on long-term renal function using chronic kidney disease staging based on glomerular filtration rate. J Vasc Surg. 2008;47:1141-1149. P.106 8. Cina CS, Abouzahr L, Arena GO, et al. Cerebrospinal fluid drainage to prevent paraplegia during thoracic and thoracoabdominal aortic aneurysm surgery: a systematic review and meta-analysis. J Vasc Surg. 2004;40:36-44. 9. Engle J, Safi HJ, Miller CC III, et al. The impact of diaphragm management on prolonged ventilator support after thoracoabdominal aortic repair. J Vasc Surg. 1999;29(1):150-156. 10. Coselli JS. The use of left heart bypass in the repair of thoracoabdominal aortic aneurysms: current techniques and results. Semin Thorac Cardiovasc Surg. 2003;15:326-332. 11. Etz CD, Homann TM, Plestis KA, et al. Spinal cord perfusion after extensive segmental artery sacrifice: can paraplegia be prevented? Eur J Cardiothorac Surg. 2007;31(4):643-648. 12. Schmitto JD, Fatehpur S, Tezval H, et al. Hypothermic renal protection using cold histidine-tryptophanketoglutarate solution perfusion in suprarenal aortic surgery. Ann Vasc Surg. 2008;22(4):520-524. 13. LeMaire SA, Jamison AL, Carter SA, et al. Deployment of balloon expandable stents during open repair of thoracoabdominal aortic aneurysms: a new strategy for managing renal and mesenteric artery lesions. Eur J Cardiothorac Surg. 2004;26:599-607.

Chapter 13 Thoracic Aortic Stent Graft Repair for Aneurysm, Dissection, and Traumatic Transection Brant W. Ullery Jason T. Lee

DEFINITION In 1994, Dake and colleagues,1 at Stanford University, were the first to report the use of customdesigned thoracic aortic stent grafts for the treatment of descending thoracic aortic aneurysms in patients deemed high risk for conventional open surgery. Each of these devices was deployed through peripheral arterial access, successfully excluding the aneurysm from systemic pressurization. This groundbreaking minimally invasive technique thereby avoided many of the physiologic insults associated with open surgery, including the need for thoracotomy, aortic cross-clamping, reperfusion injury, and acute hemodynamic changes. Results from the first multicenter U.S. Food and Drug Administration-sponsored trial for thoracic aortic stent grafts demonstrated significantly less perioperative mortality, respiratory failure, renal insufficiency, and spinal cord ischemia in patients after thoracic endovascular aortic repair (TEVAR) compared to a matched cohort of patients undergoing open descending thoracic aortic aneurysm repair.2 After two decades of surgeon experience and endovascular technologic advancement, TEVAR has evolved to serve as a primary treatment strategy for an increasingly diverse group of acute and chronic aortic pathologies including thoracic aortic aneurysms, dissections, and traumatic transections.

DIFFERENTIAL DIAGNOSIS Depending on the type and extent of pathology, TEVAR may include the use of fenestrated or branched stent grafts, advanced snorkel/chimney/periscope techniques, or the need for hybrid debranching procedures. The decision to treat thoracic aortic pathology with stent grafts is based on individual patient comorbidity burden, detailed analysis of thoracic aortic anatomy, and physician experience. Acute thoracic aortic pathologies often present with chest pain and therefore must be considered in the workup for acute coronary syndrome. The ubiquitous use of computed tomography (CT) scanning for pain, shortness of breath, trauma, and to “rule out” many pathologies has led to an increase in the recognition of thoracic aortic pathology potentially benefitting from TEVAR technology.

PATIENT HISTORY AND PHYSICAL FINDINGS Thoracic aortic aneurysms (TAAs) are defined as localized or diffuse dilation of 50% or more relative to the diameter of the adjacent normal-sized aorta. Common risk factors for aneurysmal degeneration include smoking, hypertension, chronic obstructive pulmonary disease, atherosclerosis, and connective tissue diseases. Indications for repair of descending TAAs are similar to those for conventional open repair: maximum aortic diameter greater than 6 cm, rapid aneurysmal growth (>5 mm of growth over 6 months), or symptoms such as persistent chest or back pain, rupture, or dissection. In most patients with TAA, the aneurysms were diagnosed following routine imaging ordered for other reasons and are therefore most commonly asymptomatic.

Aortic dissection occurs when an intimal tear in the aorta causes blood to flow between the layers of the wall of the aorta and most often presents as tearing chest pain that radiates to the back. Potential etiologic factors leading to aortic dissection include poorly controlled hypertension, connective tissue disorders, trauma, or vasculitis. Medical management of uncomplicated type B thoracic aortic dissection serves as the current standard of care. These practice guidelines stem from the results of the INvestigation of STEnt grafts in patients with type B Aortic Dissection (INSTEAD) trial, the first prospective, multicenter randomized trial comparing optimal medical therapy (e.g., blood pressure control) to TEVAR for uncomplicated type B dissection.3 This trial demonstrated no significant improvement in 2-year survival or adverse event rates with TEVAR despite favorable aortic remodeling, although recently reported 5-year data suggest improved longterm survival in patients undergoing TEVAR. In contrast, for patients with complicated type B dissections involving rupture, malperfusion (e.g., visceral or limb ischemia), or refractory back pain despite optimal medical management, TEVAR is indicated. The goal of TEVAR in this setting is to cover, or exclude, the primary entry tear and reexpand the true lumen while promoting thrombosis of the false lumen. Traumatic aortic transection results from a high-velocity or deceleration injury to the aorta. The tethering of the aorta by the ligamentum arteriosum makes this site most susceptible to shearing forces during sudden deceleration. A high index of suspicion is necessary to help make the diagnosis. Trauma workups most often involve whole-body CT scanning, which allows rapid triage for possible treatment. CT-A commonly demonstrates an irregular outpouching beyond the takeoff of the left subclavian artery at the aortic isthmus, which corresponds to the presence of an aortic pseudoaneurysm caused by the traumatic event. Extent of blunt traumatic aortic injury and the corresponding physiologic insult may range from clinically occult intimal injury to life-threatening complete transection and rupture (FIG 1).4 Early diagnosis and endovascular treatment is generally recommended for those presenting with a traumatic aortic transection, particularly when there is a contour abnormality visualized on cross-sectional imaging. P.108

FIG 1 • Society for Vascular Surgery classification of blunt traumatic aortic injury. (Adapted from Lee WA, Matsumura JS, Mitchell RS, et al. Endovascular repair of traumatic thoracic aortic injury: clinical practice guidelines of the Society for Vascular Surgery. J Vasc Surg. 2011;53:187-192.)

IMAGING AND OTHER DIAGNOSTIC STUDIES Transesophageal echocardiography (TEE) may serve as a useful imaging tool, particularly in the setting of acute thoracic aortic pathology. TEE can confirm the presence of aortic dissection, distinguish between types A and B dissections, identify involvement of supra-aortic vessels, and assess for contained rupture. High-resolution computed tomography angiography (CT-A) with three-dimensional reconstructive software allows for the most complete anatomic analysis, including details regarding aneurysm morphology, diameter, dissection flap characterization, thrombus burden, calcification, angulation, and branch vessel orientation. Familiarity and routine usage of three-dimensional workstations and the ability to customize measurements provide an accurate road map to guide endovascular strategy, device selection, and stent graft sizing.

SURGICAL MANAGEMENT Preoperative Planning Patients scheduled for elective TEVAR undergo routine preoperative cardiac evaluation. Based on cardiovascular risk profile, symptomatology, and presence of electrocardiogram abnormalities, selected patients undergo further evaluation in the form of an exercise stress test, dobutamine stress echocardiography, or Persantine thallium stress testing. Coronary angiography is pursued in cases involving extensive or symptomatic coronary artery disease. Aortic transections or symptomatic dissections and aneurysms should have early and aggressive blood pressure control using intravenous beta-blocker or calcium channel blocker medications. After obtaining a reliable clinical examination, refractory chest, back, or abdominal pain should be treated with narcotic analgesics. Renal protective strategies should be employed preoperatively to minimize the risk of contrast-induced nephropathy. Intravenous hydration is initiated preoperatively and, in the setting of baseline renal insufficiency, may warrant early hospital preadmission and concomitant administration of Mucomyst and bicarbonate infusion. Suspected blunt aortic injury should prompt a referral to a level I trauma center in order to facilitate early evaluation by a vascular specialist and other pertinent members of a multidisciplinary trauma team. General anesthesia is routinely performed in TEVAR cases. Prophylactic lumbar cerebrospinal fluid (CSF) drainage is P.109 considered in every case based on the relative risk of spinal cord ischemia, hemodynamic status, and acuity of clinical presentation. Arterial monitoring is performed via a right radial artery approach. Peripheral intravenous lines are typically adequate; however, more intensive central venous monitoring may be required in cases involving unstable traumatic transections, patients with significant baseline cardiovascular comorbidities, or any case involving hemodynamic instability. Preoperative imaging should be heavily scrutinized for the adequacy of iliofemoral access anatomy. An iliac conduit may be required in cases involving small-caliber, tortuous, or heavily calcified access vessels. Anticipated use of a conduit should prompt consideration of an autotransfusion or cell saver machine to be available during the procedure. Numerous variables have been identified as risk factors for the development of spinal cord ischemia after TEVAR. Given that hypoperfusion represents the primary etiology of spinal cord injury following TEVAR, commonly cited risk factors involve those relating to the extent of impairment or exclusion of the collateral perfusion to the spinal cord. The European Collaborators on Stent/Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) investigators reported results from the largest multicenter registry to date (N = 606).5 In the EUROSTAR registry, the incidence of spinal cord ischemia was 2.5% and independent risk factors included left subclavian artery coverage without revascularization (odds ratio [OR], 3.9; p = .037), concomitant open abdominal aortic surgery (OR, 5.5; p = .037), and the use of three or more stent grafts (OR, 3.5; p = .043). Based on the principle that spinal cord perfusion pressure is approximated by the difference between the mean arterial pressure (MAP) and CSF pressure, placement of a prophylactic lumbar drain has the potential to increase spinal cord perfusion pressure by decreasing CSF pressure and may be beneficial in select patients at high risk for spinal cord ischemia. Percutaneous drainage of CSF is performed by inserting a silastic catheter 10 to 15 cm into the subarachnoid space through a 14-gauge Tuohy needle at the L3-L4 vertebral

interspace. The open end of the catheter is attached to a sterile closed circuit reservoir and the lumbar CSF pressure is measured with a pressure transducer zero-referenced to the midline of the brain. Lumbar CSF can be drained continuously or intermittently in the operating room to achieve target CSF pressures of 10 to 12 mmHg. Postoperatively, intermittent or continuous CSF drainage can be continued in the intensive care unit for CSF pressures exceeding 10 mmHg or at the first sign of lower extremity weakness. In the absence of neurologic deficits, the lumbar CSF drainage catheter can be clamped 24 hours postprocedure followed by continued monitoring of CSF pressure together with serial neurologic assessments. The CSF drain can then be removed at 48 hours after operation. Although prophylactic or therapeutic lumbar CSF drainage has an established record of safety, complications have been reported to occur in approximately 1% of patients, which may include neuraxial hematoma, subdural hematoma, catheter fracture, meningitis, intracranial hypotension, chronic CSF leak, and spinal headache.

Selection and Sizing of Thoracic Stent Graft Landing zones Proximal and distal landing zones must be of sufficient length (usually at least 2 cm) to enable safe and accurate deployment bracketing the area of thoracic aortic pathology, which often includes the subclavian artery proximally or the celiac artery distally. Intentional coverage of the left subclavian artery is sometimes required due to a very proximal extent of aortic pathology, especially transections. Left subclavian artery revascularization may be required in select cases. The celiac artery rarely requires intentional coverage. Significant tortuosity, circumferential mural thrombus, and extensive calcification can compromise the proximal or distal landing zone, thereby predisposing to inadequate fixation and subsequent development of endoleak or migration. Site of proximal and distal landing zones should be selected in order to minimize the impact of these anatomic features, even if it requires extending the length of aortic coverage. A variety of anatomic measurements are taken from preoperative CT-A imaging to assist in the sizing and selection of the thoracic stent graft (FIG 2). Interventionalists should be proficient in accurate sizing and measuring of key thoracic aortic locations that influence device selection and ultimately determine patient outcomes. Sizing of stent grafts The degree of stent graft oversizing can vary based on the indication for intervention. Stent grafts are generally oversized by 10% to 20% based on the aortic diameter at the proximal and distal fixation sites for aneurysmal disease. Insufficient oversizing for the treatment of TAAs may predispose to inadequate exclusion and the potential for endoleak or migration. Aggressive oversizing, on the other hand, increases the risk for stent graft collapse, graft thrombosis, access arterial injury, and potential for peri- or postprocedural iatrogenic retrograde type A dissection. Chronic type B dissections are frequently characterized by a thick, nonmobile dissection flap, or septum, that separates true and false lumens into concave or convex discs of flow lumen. Such dissection flaps have limited compliance; therefore, minimal or no oversizing may be required in order to achieve a suitable proximal or distal seal. Aortic transections frequently occur in young trauma patients with normal or minimally diseased aortas. As such, minimal oversizing is needed to achieve an adequate seal and only recently did device manufacturers create devices meant for smaller diameter aortas. Note also that underrescucitated patients on admission will have smaller aortic diameters on their CT-A.

Currently available stent grafts range in diameter from 22 to 46 mm. Given the traditional 10% to 20% rule of device oversizing, these devices are designed to safely treat aortas with landing zones ranging from 19 to 43 mm in diameter. Access vessel anatomy Current thoracic aortic stent grafts require large-caliber delivery systems, ranging from 18 to 26 Fr in outer diameter. Small, P.110 P.111 tortuous, and heavily calcified iliofemoral arteries may prohibit sheath advancement and predispose to access site-related complications, including groin hematoma, dissection, or rupture. Careful evaluation of access vessel anatomy on preoperative imaging should be performed in order to assess the caliber, tortuosity, thrombus burden, and extent of calcification of the iliofemoral arteries. Such anatomic information will serve as the basis for deciding laterality of femoral access as well as to determine the need for an iliac conduit. Serial dilation may be attempted for patients with small iliofemoral vessels. Iliac atherosclerotic lesions may be pretreated with balloon angioplasty and/or stent grafting in order to facilitate sheath advancement and introduction of the thoracic stent graft components. Iliac conduits serve as a safe and reliable technique to circumvent issues related to suboptimal access vessel anatomy. From either flank incision, a retroperitoneal exposure provides visualization of the common iliac artery or distal abdominal aorta. A 10- or 12-mm Dacron graft is commonly used as the conduit of choice. The conduit can be modified by creating a patch at the distal end in order to further facilitate the delivery of largecaliber sheath and enable additional degrees of torqueability (FIG 3). This modification involves creating a patch by cutting the Dacron graft along its long access, thereby enlarging the transition zone from the graft to artery.

FIG 2 • Anatomic measurements to assist in thoracic stent graft device sizing and selection for the treatment of aneurysms (A) and dissections (B). DTA, descending thoracic aorta.

FIG 3 • A. 10-mm Dacron conduit bisected longitudinally to create a sewing patch. B. Dacron iliac conduit sewn to native iliac artery allows easy mobility of the conduit at multiple angles of entry for large-caliber device or sheath. (From Lee JT, Lee GK, Chandra V, et al. Comparison of fenestrated endografts and the snorkel/chimney technique [published online ahead of print April 27, 2014]. J Vasc Surg. doi:10.1016/j.jvs.2014.03.255.) EARLY PROCEDURAL CONSIDERATIONS Positioning The C-arm is typically configured in the “head” position. The left arm may be abducted to 75 to 90 degrees and circumferentially prepped into the field if an embolization or snorkel/chimney procedure involving the left subclavian artery is anticipated. The chest, abdomen, and bilateral groins should be prepped. As frequently only one groin access is required for the performance of a routine TEVAR, laterality of the operator position may vary based on surgeon preference or anticipated access site location. Establishing Vascular Access The ipsilateral femoral artery is accessed either percutaneously or from an open exposure. Secondary access may be obtained from the contralateral femoral artery or brachial artery as needed for a 5-Fr sheath and flush catheter. Surgical exposure is obtained from a small oblique incision at the level of the inguinal ligament. The common femoral artery is exposed, with proximal control obtained at the level of the external iliac artery and distal control at the level of the femoral bifurcation or proximal superficial femoral and profunda femoral arteries. Heavy calcification may require preemptive endarterectomy and patch angioplasty in order to facilitate safe sheath placement. The femoral artery is punctured using a standard micropuncture set, and if arterial access is obtained

percutaneously, a sheathogram is performed to confirm adequate puncture site location (mid-common femoral artery). A standard length Bentson wire is inserted into the aorta through micropuncture sheath and exchange for a 7-Fr sheath is then performed using Seldinger technique. Wire exchange is then done for a 260-cm stiff Lunderquist wire. The Lunderquist wire should have a flexible, curved proximal end that should be advanced under fluoroscopy across the aortic arch to abut the aortic value. The location of the distal end of the Lunderquist wire should be marked on the operating table and this wire position should be maintained throughout the procedure. Over the stiff Lunderquist wire platform, the 7-Fr sheath is removed and serial dilators are advanced to gradually enlarge the subcutaneous tract and arteriotomy site in order to accommodate either the stent graft device itself or a larger 18- to 26-Fr introducer sheath required for device delivery. After placement of the larger sheath, systemic heparin is administered at a dose of 100 units/kg (goal activated clotting time of >250 seconds). Concomitant traumatic injuries, particularly intracranial hemorrhage, may alter the dose or decision to administer heparin.

INITIAL AORTOGRAM A 5-Fr 100-cm Omniflush or pigtail catheter is inserted into aorta and advanced to the level of the aortic arch. This catheter may be advanced via a contralateral 5-Fr sheath or it may be inserted into an additional ipsilateral 5-Fr sheath placed distal to the arteriotomy for the main body delivery sheath. P.112 If satisfied with stent graft sizing based on available preoperative imaging, the thoracic aortic stent graft may be advanced over the Lunderquist wire and be positioned in the proximal to midportion of the thoracic aorta prior to initial aortogram. Optimal angiographic imaging of the aortic arch is obtained by placing the fluoroscopic C-arm in a left anterior oblique orientation, often 35 to 65 degrees, and can be optimized by referencing the preoperative CT-A. The location of the supra-aortic vessels, particularly the left subclavian artery, should be noted and marked on viewing monitors (FIG 4A). Intravascular ultrasound (IVUS) may be used an adjunct in cases involving dissection to assist in the identification of true and false lumens, as well as to gain additional information on aortic diameter, branch vessel location, and morphology of proximal and distal landing zones. IVUS also aids in limiting intravenous contrast exposure in those patients with baseline impaired renal function. If necessary to guide distal extent of stent graft placement, the celiac artery is best imaged from a full lateral projection. Additional structures to note are large, patent intercostal arteries at the level of the aortic hiatus. Efforts should be made to avoid covering these if at all possible during the course of the repair. Device Deployment Precise proximal positioning of the stent graft is facilitated by either marking the location of the left subclavian artery on the viewing screen and/or using the road-mapping feature. The distal radiopaque line of the endotracheal tube seen on fluoroscopy at about 45 degrees left anterior oblique can sometimes correlate to the position of the left common carotid artery, thereby serving as a convenient landmark in cases requiring left subclavian artery coverage. Immediately prior to stent graft deployment, systemic arterial blood pressure is reduced below 100 mmHg to reduce risk of caudal migration. The stent grafts are generally deployed in a proximal-todistal sequence. However, a distal-to-proximal

sequence may be preferred in cases involving precise deployment near the celiac artery or in aortas with significant diameter taper and a larger proximal landing zone compared to the distal landing zone (where devices of different diameter may need to be stacked up on each other). Deployed endografts will naturally extend toward the outer curvature of the aorta and precision deployment is facilitated by gently providing forward traction on the wire toward the outer curve during deployment. This P.113 maneuver also facilitates straightening out of the transverse arch, which can be helpful in minimizing the “birdbeaking” effect at the proximal graft margin, where the device may not fully oppose to the “inner” aortic wall. Bird beaking, when present, can predispose to proximal type I endoleaks, endograft collapse, and potential aortic occlusion. Additional graft components are added, when necessary, by exchanging the first device over the Lunderquist wire. A minimum overlap of 5 cm between pieces is recommended to ensure adequate apposition and minimize risk of junctional (type III) endoleak.

FIG 4 • A. Initial thoracic aortogram performed with C-arm in a 45-degree left anterior oblique orientation in a case involving a type B aortic dissection. Note how clearly the origin of the subclavian (arrow) is seen to accurately decide if there is adequate proximal neck length. B. Aortogram following deployment of thoracic stent graft with coverage of the ostium of the left subclavian artery. C. Postoperative three-dimensional imaging demonstrating successful exclusion of the proximal entry dissection tear.

Balloon Molding Balloon molding is often required in cases involving TAAs. Under fluoroscopic guidance, a noncompliant molding balloon (Coda [Cook Medical, Bloomington, IN, USA] or Tri-Lobe [W. L. Gore, Flagstaff, AZ, USA]) is advanced up to the proximal edge of the stent graft and balloon molding is performed in a proximal-to-distal sequence. Balloon molding should be performed at the proximal and distal fixation sites, as well as at areas of stent graft overlap in those cases requiring multiple stent grafts. Aggressive ballooning can cause component fracture and aortic injury, and care must be taken during inflation with constant visualization and knowledge of the tension applied to the balloon. Balloon molding is not typically required in cases involving aortic dissection or transection, particularly in cases where no obvious endoleak is visualized. Balloon molding may increase risk for iatrogenic retrograde type A conversion if performed in a region of friable or fragile aorta and is generally not recommended during dissection cases.

COMPLETION AORTOGRAM After stent graft deployment, the pigtail catheter is withdrawn along the outside of the deployed device(s) over a wire to below the level of the stent graft. The catheter is then readvanced over a wire within the stent graft lumen and positioned at the level of the aortic arch. Additional aortograms may be performed at this time as necessary in order to ensure adequate stent graft position and patency of the supra-aortic and celiac arteries and to assess for the presence of endoleaks.

REMOVAL OF SHEATH AND ARTERIOTOMY CLOSURE In cases involving percutaneous access, the two previously placed Perclose ProGlide devices are used to close the arteriotomy site(s) (see Chapter 23 for details). If open surgical exposure was obtained, proximal and distal vascular control is obtained in the respective groin. All wires and sheaths are removed. The arteriotomy is closed transversely using a polypropylene suture in either a running continuous or interrupted fashion. Antegrade and retrograde flushing maneuvers should be performed prior to completion of the arteriotomy closure.

LEFT SUBCLAVIAN ARTERY REVASCULARIZATION Endovascular procedures that require coverage of the left subclavian artery have the potential to increase the risk of spinal cord injury by compromising blood flow to the ipsilateral vertebral artery, an important collateral pathway for arterial flow to the anterior spinal artery. Subclavian artery revascularization therefore serves as an additional strategy to decrease the risk of spinal cord ischemia in select patients deemed high risk. Techniques to revascularize the left subclavian artery include transposition of the subclavian onto the left carotid artery or left carotid-subclavian bypass grafting with subsequent embolization of the left subclavian artery proximal to the bypass graft (FIG 5). These revascularization procedures may be performed as part of a staged repair or at the time of TEVAR. The existing clinical evidence to support the efficacy of routine left subclavian artery revascularization remains controversial; there are advocates for routine revascularization, selective revascularization, or no

revascularization. A meta-analysis of published studies showed a trend toward increased risk of spinal cord ischemia when the left subclavian artery was covered, suggesting a potential benefit for left subclavian artery revascularization, but the finding was not statistically significant.4,5,6

FIG 5 • Left subclavian artery transposition is performed by ligating the left subclavian artery proximal to the vertebral artery and moving it cephalad in order to perform an endtoside anastomosis between the left subclavian and left common carotid arteries. Alternatively, a Dacron graft can be used as a left carotidsubclavian bypass.

P.114 SPECIAL CONSIDERATIONS BASED ON AORTIC PATHOLOGY Aortic Dissection The primary goal of TEVAR for the treatment of dissection is coverage of the proximal entry tear (FIG 6A,B). Stent graft sizing is based on the diameter of the adjacent nondissected thoracic aorta. Minimal or no oversizing of the stent graft is recommended. In acute type B dissections, the septum is relatively mobile and compliant. Therefore, the diameter of the small true lumen in the dissected portion often returns to normal diameter following successful exclusion of the proximal entry tear. Chronic dissections have thicker, less compliant septa, which may limit expansion of the true lumen despite adequate entry tear coverage. Often, these patients have chronic false lumen aneurysmal dilation, and entry tear and fenestration covering serve simply to decrease false lumen pressurization and promote thrombosis. IVUS serves as a useful adjunct in dissection cases, both in terms of initial identification of true and false

lumen, as well as assisting in precise positioning of the device. Aortic Transection Traumatic aortic injuries are typically located along the inner curve of the proximal descending thoracic aorta (FIG 7). Given the proximal location, left subclavian artery coverage is sometimes needed.4 In the absence of concomitant hemorrhage or brain injury, routine heparin is recommended. Trauma patients are frequently hypovolemic and, as a result, may have an underdistended aorta on preoperative cross-sectional imaging. Initial cross-sectional imaging can underestimate true aortic morphology at the region of the subclavian by as much as 10% to 20%. In such settings, IVUS may assist in more accurate stent graft sizing performed in vivo.7

FIG 6 • A. CTA reconstruction demonstrating complex thoracoabdominal aortic dissection with proximal entry tear located in the proximal descending thoracic aorta. B. Initial aortogram documenting position of the supra-aortic arteries. Note the stent graft has been advanced into approximate position but is not yet deployed. P.115

FIG 7 • A. Three-dimensional reconstructed images showing the presence of traumatic aortic transection at the level of the ligamentum arteriosum (arrow). B. Aortogram showing focal outpouching (arrow) along the inner curve of the proximal descending thoracic aorta, correlating to the traumatic transection observed on preoperative imaging. Note that the stent graft has been advanced into the proximal descending thoracic aorta but is not yet deployed. C. Aortogram following thoracic stent graft deployment with successful exclusion of the transection site.

P.116 PEARLS AND PITFALLS

Indications

▪ TEVAR follows general recommendations for elective repair of descending thoracic and thoracoabdominal aortic aneurysms and should be offered to good anatomic risk patients with aneurysms >6 cm.

▪ Patient selection should take into account the need for regular interval clinical and radiologic follow-up in order to monitor for stent graft-related complications and endoleaks. Preoperative workup

▪ High-quality imaging and ability to configure three-dimensional reconstructive software are essential for successful preoperative planning and device selection. ▪ Pre- and perioperative hydration is a central part in the protection from contrastinduced nephropathy. ▪ Patients should be stratified according to baseline risk of spinal cord ischemia. A prophylactic lumbar drain should be considered in those at high risk.

Patient setup

▪ A hybrid endovascular suite provides optimal opportunity for accurate imaging and capability to perform necessary open surgical exposure or repair of accessrelated complications. ▪ Anticipated adjunct procedures, including left subclavian artery embolization or revascularization, may require prepping the left neck and/or arm into the surgical field.

Thoracic aneurysms

▪ Oversizing of stent grafts by 10% to 20% and balloon molding is generally recommended in order to maximize proximal and distal fixation. ▪ Proximal and distal landing zones should be relatively free of stenosis, calcification, and thrombus to maximize durability of this minimally invasive technology.

Type B dissection

▪ Accurate identification of true and false lumen is essential prior to deployment of the stent graft. IVUS may be a useful adjunct in this setting to confirm true or false lumen position. ▪ Aggressive oversizing of stent grafts is not recommended in patients with aortic dissection. Balloon molding is generally reserved only for those with type I or III endoleak on completion angiography and not against the region where there is a mobile septum.

Traumatic transection

▪ Routine heparin is recommended unless contraindicated by concomitant intracranial or solid organ injury. ▪ Similar to dissections, aggressive oversizing and balloon molding is not routinely performed during the treatment of transections.

POSTOPERATIVE CARE Patients are typically extubated immediately following the procedure unless prohibited by concomitant physiologic insults (e.g., hemodynamic instability, trauma patient). Intensive care unit monitoring is required for patients who require a lumbar drain for 24 to 48 hours. Immediate and frequent neurologic assessments are critical in the early perioperative period to assess for spinal cord ischemia. Raising MAP goals are an additional way to minimize risk of cord ischemia. Durability of TEVAR is reliant on routine imaging to evaluate for stent graft-specific complications postoperation. Follow-up chest CT-A and plain x-rays are typically obtained at 1, 6, and 12 months and at

intervals thereafter. Consideration should be made between balancing risks for cumulative lifetime iodinated contrast and radiation exposure versus the necessity for serial graft monitoring. In stable patients, chest x-rays may suffice to confirm device position, with CT scanning reserved for those with migration suggested by CT or evidence of progressive aortic enlargement or onset of recurrent symptoms such as chest pain.

OUTCOMES The largest published series, which has reported 1-year follow-up, included 443 patients treated with TEVAR for a variety of indications, both emergent and elective, as follows: TAA (n = 249), thoracic aortic dissection (n = 131), traumatic aortic injury (n = 50), and false anastomotic aneurysm (n = 13).8 Technical success was achieved in nearly 90% of patients, with an all-cause mortality among patients treated for aortic aneurysm and aortic dissection of 20% and 10%, respectively. No randomized trials comparing TEVAR to open surgery have been published to date. However, multiple nonrandomized comparisons suggest equivalent or better outcomes with TEVAR. In a single-center, retrospective study of over 700 patients who underwent either TEVAR or open surgery, mortality was not significantly different at 30-day (5.7% vs. 8.3%, respectively) or 1-year (15.6% vs. 15.9%, respectively) follow-up.9 Two smaller studies demonstrated a reduction in 30-day perioperative mortality with TEVAR compared with open surgery (1.9% vs. 5.7%).10,11

COMPLICATIONS Stroke continues to be a common complication following TEVAR and is associated with significant inhospital mortality. Recent clinical series have reported an incidence of stroke after TEVAR to range from 2% to 8%.12,13 The underlying mechanisms contributing to acute ischemic stroke after TEVAR and the temporal relationship of stroke to the procedure are not completely understood. However, the constellation of preoperative risk factors, neurologic examinations, and patterns of brain infarction observed in these patients has led most investigators to conclude that cerebral embolization and ischemic events are the primary mechanisms for perioperative stroke in TEVAR.5,13,14 Embolic events are related to instrumentation of the aortic arch in P.117 patients with severe atheromatous disease, whereas ischemia is a result of the planned or inadvertent endovascular coverage of supra-aortic vessels. Spinal cord ischemia and subsequent acute or delayed paraplegia represents the most devastating complication of TEVAR. The pathogenesis of spinal cord injury after TEVAR is likely multifactorial but still poorly understood. The deployment of thoracic stent grafts results in rapid complete exclusion of varying lengths of segmental collateral vessels without the ability to surgically reimplant or revascularize the intercostal arteries. Stent deployment and catheter manipulation can predispose patients to dislodgement of thrombotic or atheromatous debris from the aortic wall into segmental vessels, with subsequent distal embolization and occlusion of arteries supplying the spinal cord. Moreover, endovascular coverage of the left subclavian artery may compromise spinal cord perfusion in patients with a dominant left vertebral artery, solitary vertebral artery, carotid artery disease, or an incomplete circle of Willis. Access site injuries to the iliofemoral vessels may further increase the risk of spinal cord ischemia by compromising collateral flow to the anterior spinal artery through the hypogastric and pelvic vascular plexus. Lastly, pharmacologic measures aimed at decreasing arterial blood pressure to enhance accuracy of device

deployment in cases involving difficult aortic anatomy may lead to hypotension similar to that observed in open surgery. Due to the large sheath sizes required for the delivery of thoracic stent grafts, small-diameter, tortuous, or heavily calcified access vessels can predispose to iliofemoral arterial injury. Postoperative CT-A often documents arterial dissections and injury that can be followed with noninvasive duplex and managed expectantly until patients have claudicationlike symptoms. Endoleaks are a relatively common finding after TEVAR, affecting nearly 15% of patients in the early or late postoperative periods. Type I or III endoleaks typically require additional stent placement or balloon molding in order to improve proximal, distal, or junctional fixation. Most type II endoleaks observed on completion angiogram or early followup cross-sectional imaging will resolve spontaneously. Persistent type II endoleaks, especially those with aneurysm sac expansion or failure to adequately seal a proximal entry tear or transection, warrant additional intervention. Retrograde flow from intercostal or left subclavian arteries can be treated using coil embolization or vascular plug placement.

REFERENCES 1. Dake MD, Miller DC, Semba CP, et al. Transluminal placement of endovascular stent-grafts for the treatment of descending thoracic aortic aneurysms. N Engl J Med. 1994;331:1729-1734. 2. Bavaria JE, Appoo JJ, Makaroun MS, et al. Endovascular stent grafting versus open surgical repair of descending thoracic aortic aneurysms in low-risk patients: a multicenter comparative trial. J Thorac Cardiovasc Surg. 2007;133:369-377. 3. Nienaber CA, Rousseau H, Eggebrecht H, et al. Randomized comparison of strategies for type B aortic dissection: the INvestigation of STEnt Grafts in Aortic Dissection (INSTEAD) trial. Circulation. 2009;120:2519-2528. 4. Lee WA, Matsumura JS, Mitchell RS, et al. Endovascular repair of traumatic aortic injury: clinical practice guidelines of the Society for Vascular Surgery. J Vasc Surg. 2011;53:187-192. 5. Buth J, Harris PL, Hobo R, et al. Neurologic complications associated with endovascular repair of thoracic aortic pathology: incidence and risk factors. A study from the European Collaborators on Stent/Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) registry. J Vasc Surg. 2007;46:1103-1110. 6. Rizvi AZ, Murad MH, Fairman RM, et al. The effect of left subclavian artery coverage on morbidity and mortality in patients undergoing endovascular thoracic aortic interventions: a systematic review and metaanalysis. J Vasc Surg. 2009;50:1159-1169. 7. Pearce BJ, Jordan W. Using IVUS during EVAR and TEVAR: improving patient outcomes. Semin Vasc Surg. 2009;22:172-180. 8. Leurs LJ, Bell R, Degrieck Y, et al. Endovascular treatment of thoracic aortic diseases: combined experience from the EUROSTAR and United Kingdom Thoracic Endograft registries. J Vasc Surg. 2004;40: 670-679.

9. Greenberg RK, Lu Q, Roselli EE, et al. Contemporary analysis of descending thoracic and thoracoabdominal aneurysm repair: a comparison of endovascular and open techniques. Circulation. 2008;118:808-817. 10. Matsumura JS, Cambria RP, Dake MD, et al. International controlled clinical trial of thoracic endovascular aneurysm repair with the Zenith TX2 endovascular graft: 1-year results. J Vasc Surg. 2008;47(2): 247-257. 11. Bavaria JE, Appoo JJ, Makaroun MS, et al. Endovascular stent grafting versus open surgical repair of descending thoracic aortic aneurysms in low-risk patients: a multicenter comparative trial. J Thorac Cardiovasc Surg. 2007;133:369-377. 12. Feezor RJ, Martin TD, Hess PJ, et al. Risk factors for perioperative stroke during thoracic endovascular aortic repairs (TEVAR). J Endovasc Ther. 2007;14:568-573. 13. Gutsche JT, Cheung AT, McGarvey ML, et al. Risk factors for perioperative stroke after thoracic endovascular aortic repair. Ann Thorac Surg. 2007;84:1195-1200. 14. Fattori R, Nienaber CA, Rousseau H, et al. Results of endovascular repair of the thoracic aorta with the Talent Thoracic stent graft: the Talent Thoracic Retrospective Registry. J Thorac Cardiovasc Surg. 2006;132:332-339.

Chapter 14 Exposure and Open Surgical Management at the Diaphragm Peter H. U. Lee Ramin E. Beygui

DEFINITION Thoracoabdominal aneurysms and complicated descending aortic dissections are the two most likely reasons for requiring surgical exposure of the diaphragm in vascular surgery. The need to expose the aorta both above and below the diaphragm requires an extended incision spanning the left thorax to the abdomen, the length and exact location of which depends on the location of the targeted aortic pathology. Often, the diaphragm must be divided, necessitating an awareness of the regional anatomy as well as various surgical management considerations.

DIFFERENTIAL DIAGNOSIS Thoracoabdominal aneurysm: The Crawford classification categorizes thoracoabdominal aneurysms according to the extent of the aneurysm and is the most widely used1 ( FIG 1). The classification is as follows: type I, from the left subclavian artery to just above the renal arteries; type II, from the left subclavian artery to the infrarenal aorta; type III, from the mid-descending thoracic aorta to below the renal arteries; type IV, from the diaphragmatic aorta to the iliac bifurcation; and type V (modified classification by Safiet al.2): from the middescending thoracic aorta. Descending (type B) aortic dissection: Two classifications systems are commonly used to describe the extent of aortic dissections (FIG 2). Stanford type A dissections involve the ascending aorta with or without involving the descending aorta, whereas type B dissections only involve the descending aorta beyond the left subclavian artery. The DeBakey classification includes type I, which involves both the ascending and descending aortas; type II, which involves only the ascending aorta; and type III, which involves only the descending aorta.

PATIENT HISTORY AND PHYSICAL FINDINGS Most patients who are referred for surgery for a thoracoabdominal aneurysm present with no symptoms. However, when they do have signs and/or symptoms, they may present with pain in the chest, abdomen, or lower back; a mass in the abdomen, which may be pulsatile, or rigid abdomen; and evidence of atheroembolism distally. The aforementioned symptoms, with signs of hypovolemic shock, may indicate a ruptured aneurysm. Uncomplicated descending aortic dissections are generally managed medically. However, if the dissection is complicated, such as when it is associated with significant symptoms or leads to visceral or distal malperfusion, rapid surgical intervention is warranted. A more complete discussion regarding indications for intervention in aortic dissections and thoracoabdominal aortic aneurysm can be found in a number of relevant reference textbooks.

IMAGING AND OTHER DIAGNOSTIC STUDIES

Imaging is used to determine the proximal and distal extent of repair required. It impacts the type of exposure required (i.e., thoracotomy vs. laparotomy vs. thoracoabdominal incision) as well as the level of incision. If the exposure is for the repair of thoracoabdominal aortic pathology, all patients require adequate preoperative imaging, ideally consisting of a computed tomography aortography (CTA) with or without 3-D reconstruction. Magnetic resonance aortography (MRA) may also provide the necessary information, but this generally requires more time, is more expensive, and requires more extensive postprocessing. However, MRA is the study of choice when CTA is contraindicated or unsafe, such as in patients with a contrast allergy or renal insufficiency. Catheter-based invasive aortography has generally been supplanted by CTA and MRA as the primary preoperative imaging P.119 modality of choice, as it is more cumbersome and does not provide a complete assessment of the aneurysm, including thrombus volume and adjacent anatomic structures. If the surgery is elective, as in the case of an incidentally found aneurysm, extensive preoperative evaluations are necessary to minimize postoperative morbidity and mortality. Thorough evaluations of the cardiac, pulmonary, and renal systems are necessary, especially because these systems are most commonly affected when there are complications. Depending on the risk factors and prior history, further testing may be required and patients should be referred to appropriate specialists for proper evaluation. A good neurologic evaluation is also warranted, particularly if the patient has a prior history or symptoms suggestive of a lower extremity weakness or spinal injury.

FIG 1 • Modified Crawford classification.

FIG 2 • Stanford/DeBakey classification.

SURGICAL MANAGEMENT Preoperative Planning Determine the possible need for adjuncts such as cardiopulmonary bypass and neurophysiologic monitoring. In some instances, pulmonary artery catheters may be warranted for monitoring cardiovascular hemodynamics. Assess the need for spinal cord protection, including the use of lumbar drainage of cerebrospinal fluid (CSF), distal aortic perfusion, epidural cooling, and distal aortic perfusion. Given the expected amount of blood loss, a Cell Saver and rapid infuser should be available. Double lumen endotracheal tube should be used for singlelung ventilation of the right lung. Bronchial blockers are not reliable adjuncts for this purpose.

Positioning Initially, place the patient supine on a deflated beanbag (FIG 3). Roll the left chest upward and toward the right and place a shoulder roll under the right axilla and a bump under the left scapula while also gently pulling and securing the right arm over to the right side. Ideally, the upper back should be rotated about 60 degrees to the table with the pelvis remaining flat, such that the trunk is twisted to the right. Position the patient with the break located halfway between the left costal margin and the left iliac crest. Jackknife the table and then inflate the beanbag. Be sure to support and secure the arms (“airplane” splint for the left arm) and pad all pressure points on the body and extremities. Prep the left chest with the following boundaries: the axilla superiorly, the spine posteriorly, and the sternum and abdomen beyond the right of midline anteriorly. Keep the groins in the field for surgical access to the femoral vessels for possible cannulation if necessary.

FIG 3 • Positioning.

PLANNING THE INCISION This chapter deals with distal thoracic aortic pathology requiring exposure of the diaphragm where a simple thoracotomy incision would not be adequate. Such more limited pathologies are described elsewhere. The proximal extent of the pathology and the anticipated location of the proximal clamp determine the level of the thoracic portion of the incision. If the proximal clamp is to be placed between the aortic arch and just beyond the left subclavian artery, the chest is entered through the 4th or 5th intercostal spaces (e.g., Crawford types III and V aneurysms). P.120 If the proximal clamp is to be placed just above or at the diaphragm, the 8th or 9th interspace should be entered (e.g., Crawford type IV aneurysms). Consider the possible use of parallel or “double” thoracotomy incisions if exposure of both the proximal and distal extent of the thoracic aorta is needed. In this case, the skin incision is placed between the levels of the two interspaces anticipated to be entered. The length and location of abdominal incision is determined by distal extent of the aortic pathology. A modified thoracoabdominal incision that does not extend to midline is adequate if limited exposure of the abdominal aorta to the level of the celiac artery is required. Extend the incision to the midline for exposure of the visceral aorta. The incision should be extended down the abdominal midline for more extensive exposure of the infrarenal abdominal aorta (types II, III, and IV) to the aortic bifurcation or common iliac arteries (FIG 4).

FIG 4 • Thoracoabdominal incision.

THE INITIAL INCISION AND EXPOSURE Mark where the incision is to be made including finding the appropriate interspace and the extent of the abdominal incision as described earlier. Start with the thoracic incision over the appropriate interspace and then extend it across the costal margin. Depending on the degree of the abdominal exposure required, extend this incision obliquely to the midline of the abdomen. The midline incision can then be extended to the level of the symphysis pubis, if necessary. The abdominal incision is carried through the subcutaneous tissues, the external abdominal oblique aponeurosis, and the anterior rectus sheath. Split the external abdominal oblique muscle in the direction of its fibers. Divide the underlying internal oblique and transversus abdominus muscles between the costal margin

and lateral edge of the rectus sheath. Divide left rectus muscle. The thoracic incision should provide adequate exposure posteriorly and should be extended to the erector spinae fascia. Expose the intercostal muscles by incising through the subcutaneous tissues and the external oblique fascia.

ABDOMINAL EXPOSURE Develop the abdominal portion of the incision before entry into the left pleural cavity The aorta may be exposed by an extraperitoneal or transperitoneal approach. Extraperitoneal: This approach is ideal for repairing thoracoabdominal aneurysms, especially those involving the upper abdominal aorta (FIG 5). Develop the plane between the transversalis fascia and the parietal peritoneum. Separate the peritoneum from the lateral and posterior abdominal walls as well as from the diaphragm superiorly. Transperitoneal: This approach provides better exposure for visceral artery revascularization when required, especially when bypass is required to the right renal artery. Additional details of these approaches can be found elsewhere and are beyond the scope of this chapter. P.121

FIG 5 • Abdominal aortic exposure via extraperitoneal approach.

THORACIC EXPOSURE Develop a plane superficial to the ribs and intercostal muscles. Hold ventilation to the left lung and allow it to collapse. Enter the left chest by opening the intercostal space along the superior edge of the lower rib, making sure not to injure the lungs. To maximize the exposure, it may be necessary to perform a subperiosteal resection of the rib above or below the interspace entered, depending on the target location. Additional exposure can be obtained from “notching” an adjacent rib. This is accomplished by excising a 2-cm segment of the rib posteriorly If two interspaces are being entered, develop an adequate plane anterior to the ribs. The skin and overlying muscles can be retracted to accommodate both thoracic interspace exposures. Use a self-retaining retractor to maintain exposure. Be aware that there can be extensive adhesions within the pleura that may predispose to lung injury.

Usually, these adhesions can be mobilized bluntly if thin but may need bovie cautery or scissors if more substantial.

EXPOSURE AND DIVISION OF THE DIAPHRAGM Release any adhesions that may be present, mobilize the lung by dividing the inferior pulmonary ligament, and retract the lung cephalad to expose the diaphragm. Next, join the left thoracic cavity and the retroperitoneum or abdomen by dividing the diaphragm. The diaphragm can be incised partially or completely (FIG 6). Partial incision: Incise the muscular portion of the diaphragm and preserve the central tendinous portion. This approach minimizes respiratory complications. Complete division: This approach provides the best exposure of the aorta. This extends the incision from the divided costal margin to the aortic hiatus. Division can be accomplished either radially or circumferentially. Be sure to leave approximately 2 to 3 cm of diaphragm from the internal costal margin to aid in the later closure of diaphragm. The circumferential approach also theoretically minimizes disruption of the phrenic nerve and is generally preferred.

FIG 6 • Division of the diaphragm.

P.122

CLOSURE After completion of the core surgical procedure, close the diaphragm. Take patient out of flexed position and close the diaphragm with heavy running suture. Place chest tubes. Reapproximate the interspace with multiple simple or figure-of-eight heavy (no. 1) nonabsorbable suture. Close the incision in layers, including the muscle with running Vicryl as well as the deep dermal layer. Close the skin with subcuticular sutures or staples.

PEARLS AND PITFALLS Indications

▪ Preoperative CTA or MRA is mandatory to determine the suitability of the aortic pathology for surgical repair.

Placement of incision

▪ The placement of the incision should be carefully considered preoperatively based on imaging and the extent of the pathology. A single thoractomy incision can be placed even if two intercostal spaces need to be entered. To minimize morbidity, begin with a smaller incision because it can always be extended when necessary.

Injury to phrenic

▪ A circumferential division of the diaphragm can provide the best exposure while also minimizing the risk of injury to the phrenic nerve.

Closure

▪ When carrying out a circumfrential division of the diaphragm, leave 2 to 3 cm of diaphragm from the internal costal margin for the repair of the diaphragm when closing.

POSTOPERATIVE CARE Monitor in the surgical intensive care unit as necessary for the extent of the aortic reconstruction required. Remove chest tubes when drainage is adequately low. Continuous spinal cord protection and neurologic monitoring immediately postoperatively; continue CSF drainage for ˜3 days. Follow-up imaging with CTA to establish a baseline Standard postoperative incision and wound care

OUTCOMES It is proposed that pulmonary dysfunction associated with thoracoabdominal aortic surgery is to a large part associated with diaphragmatic dysfunction. Stickley and Giglia3 recommend a new technique using a gastrointestinal stapler to divide the diaphragm. This technique is proposed to be “rapid, hemostatic, and aids with reapproximation at the completion of the case” and that “this method of diaphragm division

is quicker and less traumatic and has the potential to decrease the incidence of postoperative pulmonary dysfunction.” Huynh et al.4 conclude that renal failure, spinal cord deficit, and pulmonary complication were the major determinants of length of stay (LOS) in patients for thoracoabdominal aortic aneurysm (TAAA) repair. Their study has shown that the preservation of diaphragmatic function and the use of the adjunct distal aortic perfusion and CSF drainage may reduce hospital LOS.

COMPLICATIONS Bleeding; take back Phrenic nerve palsy or paralysis Diaphragmatic hernia Pulmonary complications, respiratory failure Wound complications Paralysis; spinal cord ischemic injury, associated with thoracoabdominal aortic surgery Stroke/transient ischemic attack (TIA), associated with thoracoabdominal aortic surgery Multiorgan failure, associated with thoracoabdominal aortic surgery Death, associated with thoracoabdominal aortic surgery

REFERENCES 1. Crawford ES, Crawford JL, Safi HJ, et al. Thoracoabdominal aortic aneurysms: preoperative and intraoperative factors determining immediate and long-term results of operations in 605 patients. J Vasc Surg. 1986;3(3):389-404. 2. Safi HJ, Winnerkvist A, Miller CC III, et al. Effect of extended crossclamp time during thoracoabdominal aortic aneurysm repair. Ann Thorac Surg. 1998;66(4):1204-1209. 3. Stickley SM, Giglia JS. Novel use of a gastrointestinal stapler for diaphragm division during thoracoabdominal aortic exposure. Ann Vasc Surg. 2013;27(5):689-691. doi:10.1016/j.avsg.2012.11.005. 4. Huynh TT, Miller CC III, Estrera AL, et al. Determinants of hospital length of stay after thoracoabdominal aortic aneurysm repair. J Vasc Surg. 2002;35(4):648-653.

Chapter 15 Retroperitoneal Aortic Exposure Matthew Mell

IMAGING AND OTHER DIAGNOSTIC STUDIES General Considerations Retroperitoneal aortic exposure may be desirable for a variety of vascular conditions, including abdominal aortic aneurysms, aortoiliac occlusive disease, and mesenteric or left renal artery occlusive disease. Retroperitoneal exposure may be preferred for patients with a hostile abdomen from previous intraabdominal infection, surgery, or radiation. Compared with transabdominal aortic exposure, retroperitoneal exposure may be associated with shorter postoperative ileus, decreased pulmonary complications, decreased pain, and lower incidence of late complications including small bowel obstruction or aortoenteric fistulae.1 Retroperitoneal aortic exposure can be converted, when necessary, to thoracoabdominal exposure with excellent visualization of the superior mesenteric artery (SMA), left renal artery, celiac axis, and descending thoracic aorta.2 Examination of intraabdominal contents is possible through a retroperitoneal approach by simply opening a peritoneal window as necessary.

Preoperative Imaging Prior to aortic reconstruction, detailed anatomic imaging derived from modern, multirow detector computed tomographic arteriography (CTA) will greatly facilitate surgical planning. Image acquisition should extend from the normal proximal aorta to the common femoral artery bifurcations bilaterally. Runoff imaging may also aid decision making depending on clinical circumstances. Data derived from submillimeter imaging slices may be readily reformatted into multiplanar and 3-D reconstructions, with excellent resolution of the peripheral mesenteric and renal vasculature. Noncontrast images should also be obtained to help assess the degree of mural calcification present in diseased proximal aorta. Recognition of extensive mural calcification may modify the location chosen for clamp placement, or prohibit safe clamping entirely in diseased segments. CTA may require larger contrast dose than that required for catheter-based contrast aortography. Contrast volumes required for CTA may be reduced significantly by modifying the field of view or imaging parameters required for the procedure. Consultation with the responsible radiologist will ensure optimal imaging of the necessary arterial anatomy with minimal contrast and radiation exposure. Contrast-based aortography, either CT or catheter-based, may be contraindicated for patients with reduced creatinine clearance or an anaphylactic reaction to contrast. Milder allergic responses (hives, rash) may be successfully tempered by premedication with steroids and antihistamines, depending on the relative indication for contrast administration and the patient’s overall medical condition. Adverse effects of intravenous or intraarterial contrast administration on creatinine clearance may be partially ameliorated by preprocedural oral or intravenous hydration and administration of N-acetylcysteine (Mucomyst). Although sometimes considered a reasonable alternative under these circumstances, gadolinium-based contrast administration for magnetic

resonance arteriographic indications is also contraindicated in patients with a creatinine clearance less than 60 mL per minute. When contrast administration is absolutely out of the question, CT images acquired without contrast may provide adequate anatomic imaging to proceed with surgery, with the caveat that anomalies such as a retroaortic left renal vein may be present and unrecognized until exposed at surgery.

SURGICAL MANAGEMENT Instrumentation In addition to standard vascular instrumentation, additional equipment may aid in exposure of the aorta and its visceral branches from the retroperitoneal approach: Beanbag and airplane for positioning A fully articulated operative table, capable of flex and reflex at the level of the umbilicus Self-retaining, table-mounted retractor (e.g., Bookwalter, Omni, or other) Finochietto chest retractor Nos. 3, 4, and 5 Fogarty occlusion balloons Cold renal perfusion Arterial cannulas for renal perfusion

Positioning The patient is placed supine on a beanbag and all lines and tubes are placed. For exposure of the infrarenal aorta and iliac arteries, the left shoulder is lifted and protected with the beanbag and padding. The left arm can be abducted or rotated to the patient’s right with a padded airplane retractor for support. The table break and the kidney bar are used to open up the retroperitoneal space between the 12th rib and the iliac crest as the incision is developed. For this reason, it is essential that the patient be positioned with the umbilicus on the table break. An oblique incision is made from below the umbilicus to the tip of the 11th rib. With this location, the incision can be extended into the 10th intercostal space and the chest entered if additional proximal exposure is required (FIG 1). When additional iliac artery or pelvic exposure is anticipated, the incision should be initiated distal to the umbilicus. Either way, in patients with considerable P.124 abdominal girth and redundant pannus, landmarks should be confirmed to ensure that the incision is not placed too far distally on the abdomen, as juxtarenal aortic control can be extremely difficult when the incision is placed too far distally on the abdomen. For thoracoabdominal exposure, the patient is placed in the right lateral decubitus position using a beanbag and axillary role for support. The left arm is protected with adequate padding and an airplane-type retractor. It is important to secure the left arm such that the scapula rolls anteriorly, providing exposure of the posterior lateral chest. The incision will be made overlying the 8th intercostal space and extended toward the umbilicus.

FIG 1 • Patient position for thoracoabdominal exposure with incision in the 8th intercostal space (dotted line). Positioning is supported with a beanbag and right axillary roll.

The incision is carried through the external oblique, internal oblique, and transversus abdominis muscles. The retroperitoneal space is then entered laterally near the tip of the 11th rib by identifying the characteristic yellow preperitoneal fat. The retroperitoneal space is then developed from lateral to medial using a sponge stick or hands for blunt dissection. Anteriorly, the peritoneum tends to be more adherent at the level of the rectus sheath; care should be taken to avoid entering the peritoneal cavity in this area. The psoas fascia is encountered as the dissection is developed posteriorly in the course of this dissection, which leads directly to the left iliac vessels and ureter. Dissection is continued proximally anterior to the ureter; the ureter is either left in situ to limit injury or gently retracted medially with silastic slings as the retroperitoneal space is developed. Superiorly, the kidney is identified as the dissection is continued anterior to Gerota’s fascia—a potential space exists between descending colon and Gerota’s fascia in the retroperitoneum, which is

progressively developed in a cephalad direction from the psoas muscle, adjacent to the aorta. Once the renal vein is visualized in this space, the superior margin of the dissection is complete. If suprarenal aortic control and exposure is required, this same dissection plane should be developed posterior to the kidney, elevating the kidney and ureters along with the peritoneal contents and retracting all to the right to expose the subdiaphragmatic visceral aorta. Self-retaining retractor systems are best deployed either after the psoas muscle is identified or following exposure of the renal vein or elevation of the left kidney. Deploying the retractor system earlier will interfere with the dissection necessary to access the appropriate retrocolic space. Following placement of the initial padded retractor blade along the medial margin of the wound, circumferential retraction is secured by placement of additional blades, typically opposite each other to prevent undue tension on the retraction system, with sequential replacement with deeper blades and additional retraction until the entire periaortic retroperitoneum is exposed. The aorta and iliac arteries are then dissected free of surrounding tissue. Circumferential aortic control is an essential safety element of all aortic procedures, and care should be taken to gently and patiently create a space between the inferior vena cava (IVC), aorta, and vertebral bodies posteriorly to pass an umbilical tape around the aorta with a right-angle clamp. Circumferential control of the common iliac arteries, on the other hand, is not necessary in all circumstances. Sufficient medial and lateral dissection to allow for placement of a Wylie hypogastric clamp around the common iliac artery will usually suffice. Avoidance of attempts at circumferential iliac control will reduce the risk of right iliac vein injury. When circumferential control is required, patience is necessary to gradually separate the right common iliac artery from the distal IVC and left common iliac vein. When a venous injury is encountered during this maneuver, division of the common iliac artery may be necessary to gain adequate exposure for control. Alternatively, an occlusion balloon may be introduced from the right common femoral or external iliac veins will tamponade the venous P.125 bleeding until sufficient exposure is gained to repair the wound. Finally, a covered self-expanding endograft may also be deployed over a wire to gain control. Again, readjustment of the retractor system with each consecutive stage of exposure will optimize operative efficiency. Frequently, to optimize distal exposure, the proximal retractor blades need to be temporarily relaxed and vice versa. This exposure provides adequate exposure to the infrarenal aorta (and inferior mesenteric artery if reimplantation is anticipated), right and left common and left external iliac arteries. The right external iliac artery is not well visualized from this approach, although tunneling to the right femoral artery is readily achieved for aortofemoral bypass grafting when necessary. Care should be taken to develop the tunnel immediately anterior to the iliac arteries to avoid injury to the right ureter or trapping the ureter between the graft limb and adjacent artery. When right external iliac artery exposure is required during a left retroperitoneal exposure, a counterincision may also be placed in the right lower quadrant, although patient positioning and retractor system placement may limit the potential use of this maneuver. For procedures requiring more proximal, visceral aortic exposure, the latissimus dorsi is identified and dissected from surrounding superficial and deep tissues and retracted laterally. The 8th intercostal space is opened posteriorly to the paraspinal muscles and anteriorly to the costal margin, which is divided. As the retroperitoneal space is developed, the peritoneum is bluntly separated from the inferior surface of the diaphragm. The diaphragm is divided in a circumferential manner 1 to 2 cm from its attachments to the chest wall to avoid injury to the phrenic nerve (FIG 2). The median arcuate ligament is identified and divided. Proximal aortic control can now be obtained under direct vision, again following strategic placement of self-retaining retractor blades, taking care to identify and avoid injury to the esophagus. Dissection of the plane posterior the Gerota’s fascia allows for exposure of the left renal artery, which is

an important landmark in further dissection of the visceral aorta. Once the origin of the left renal artery is identified and the median arcuate ligament has been divided, the visceral aorta and origins of the celiac axis and SMA can be isolated with sharp dissection. With the left kidney rotated anteriorly, the SMA can be exposed over a distance of approximately 5 cm (FIG 3). P.126 Additional exposure can be obtained by rotating the kidney posterior to expose the SMA as it courses behind the pancreas (FIG 4). Following vascular repair, the retroperitoneal space should be inspected for hemostasis. The ureter should be inspected, and any suspected injury or leak can be investigated with intravenous methylene blue. If needed, the peritoneum can be opened for inspection of abdominal contents. Removing the table break or lowering the kidney bar if used will aid in approximating tissue layers without tension. If divided, the diaphragm can be reapproximated with a continuous running absorbable suture. The suture can be secured at the anterior costal margin and will help approximate these structures as well. If the thorax was entered, a large-bore chest tube is placed dependently and secured with U stitches. A large Blake or Jackson-Pratt drain can be placed in the retroperitoneal space to avoid early postoperative fluid collections. The muscular layers are closed with continuous absorbable sutures and the subcutaneous tissue and skin closed with standard techniques.

FIG 2 • The diaphragm is incised circumferentially (dotted line) to protect the phrenic nerve and thereby preserve diaphragmatic function. A one-to two centimeter cuff of diaphragm is left attached to the chest was to aide in closure.

FIG 3 • Exposure of the visceral aorta with the left kidney lifted to expose the left renal artery and the entire posteriorlateral aorta. Note that the left renal vein rolls off the aorta.

FIG 4 • Exposure of the visceral aorta with the left kidney left in situ. This approach allows for additional exposure of the proximal superior mesenteric artery.

PEARLS AND PITFALLS ▪ Choosing the most appropriate procedure for any given patient with mesenteric or renal artery occlusive disease is dependent on a multitude of factors, especially with the widespread availability of percutaneous interventions. Open surgical procedures continue to remain an excellent alternative for patients with multivessel disease, with coexisting aortoiliac occlusive or aneurysmal disease, and with disease too extensive to be adequately treated with wire-based techniques. When selecting from the variety of open procedures, patient comorbidity, body habitus and its impact on adequate exposure, quality of the inflow and outflow vessels, and ability to safely clamp vessels should all be taken into consideration. Having a working knowledge of all alternatives is important, as occasionally, intraoperative findings dictate a deviation from the preoperative plan.

▪ Intraoperative management is similar to that for other abdominal vascular procedures. When the dissection is complete, patients are given heparin at a dose of 100 units/kg prior to clamping vessels, achieving a target activated clotting time (ACT) of 200 to 250 seconds. For cases where renal perfusion is interrupted, 0.25 to 0.5 g/kg of mannitol is given prior to cross-clamping. As soon as possible, the kidney is perfused with 300 to 400 mL of saline cooled to 4°C. This may be done at the renal artery ostium immediately after a renal endarterectomy, or directly into the renal artery at the level of the distal anastomosis. Renal artery cannulas, which come in a variety of sizes, are used for perfusion. Using a size that most closely matches the diameter of the renal vessel assures that the perfusate will go into the kidney and not spill onto the operative field. ▪ When revascularization is complete, heparin is reversed with protamine while checking for hemostasis. The patency of revascularization may be checked with intraoperative duplex imaging. Confirmation of an adequate endpoint is especially important when endarterectomy has been performed, as intimal flaps may present as a delayed vessel occlusion and end-organ loss.

POSTOPERATIVE CARE In addition to the standard postoperative strategies for patients undergoing aortic surgery, including serial hematocrit and hemoglobin, electrolytes, creatinine, and lactic acid, it is important to monitor renal and intestinal function. Patients undergoing renal revascularization commonly have an obligatory diuresis for the first 12 hours after surgery. This phenomenon may be due to residual effects of operative mannitol as well as a response to transient renal ischemia. During this time, urine output is not reflective of the patient’s overall volume status, and crystalloid should be given at rates sufficient to maintain central filling pressures. Also, serum creatinine should be serially measured. It is common for the serum creatinine to increase slightly in the first 1 or 2 postoperative days, but increases of more than 20% or 30% warrant further investigation, especially if associated with oliguria. Sudden changes in renal function that are unexplained or unresponsive to corrective measures warrant duplex imaging to determine renal perfusion. P.127 Patients after mesenteric revascularization often develop hyperactive peristalsis, sometimes while the incision is still open. Under these circumstances, serial examination for bowel sounds in the first 24 hours can provide clues to the continued patency of the revascularization. Serial lactate levels are also checked. Although immediate postoperative lactate levels are elevated, they should return to normal as the patient is warmed and resuscitated. Coagulation parameters may also be elevated initially in response to blood loss and transient hepatic ischemia. These parameters should be monitored and corrected for active bleeding; normal values are usually present by the first postoperative day.

COMPLICATIONS General Considerations As with all aortic surgery, potential complications after visceral artery revascularization include myocardial infarction, respiratory failure, and postoperative bleeding. Additionally, renal failure is always a potential complication during visceral revascularization, although its incidence is low.3-5 Potential causes of renal failure include generalized hypoperfusion from cardiac dysfunction or hypovolemia, prolonged intraoperative ischemia, or thrombosis of the repair. Progressive or unexpected renal failure should initiate a prompt workup including duplex imaging of the kidneys to identify potentially treatable causes.

Thrombosis with absence of flow to the kidney is generally irreversible unless identified immediately. Intestinal ischemia is the major concern after mesenteric revascularization. Signs and symptoms may include severe abdominal pain, continued acidosis, and hematochezia. Ischemia may be secondary to vessel or graft thrombosis or may result from distal embolization during or following the repair. Patients with evidence of peritonitis should be promptly reexplored, and those treated initially for acute mesenteric ischemia should have a planned second look at 12 to 24 hours if there was any question of intestinal viability at the time of the original operation. Arterial duplex may confirm the viability of the repair but cannot rule out embolization as a cause for postoperative intestinal ischemia. At exploration, nonviable intestine can be resected, and issues with the revascularization can be addressed.

Graft or Vessel Twisting or Kinking When performing a bypass to the SMA, it is important to retract the mesentery in a caudal direction to adequately assess graft length. Inadequate positioning will result in excessive graft length and potential kinking and thrombosis once the peritoneal contents are reduced to the abdomen and the incision is closed. Additionally, for retrograde bypass, the graft should be placed with enough slack to allow the distal endpoint to be in-line with the SMA with caudal retraction of the intestines. This positioning will prevent both kinking of the graft and tenting and narrowing of the anastomosis. Bypass to the renal arteries should similarly be constructed with appropriate graft length as it will lay in the retroperitoneum after retraction is released. For cases of arterial reimplantation, it is important to maintain orientation of the target vessel to prevent twisting during construction of the anastomosis. Additionally, the anastomotic site should be chosen in a similar coronal plane to prevent kinking once the end organs assume their natural position.

Injury during Endarterectomy Identifying the appropriate endarterectomy plane is usually straightforward in the aorta, renal arteries, and SMA. The celiac artery can be challenging, as it may be thin-walled, and plaque removal may injure the arterial wall. Limited injuries can be repaired with interrupted 4-0 or 5-0 Prolene sutures supported with Teflon pledgets, but larger injuries or those with severely attenuated vessel walls may not be successfully repaired with this technique. If the integrity of the artery is in doubt, it may be safer to transect it and perform a bypass from the aorta to the transected celiac artery using an 8-mm or 10-mm graft. The celiac artery stump can be oversewn with pledgeted 3-0 Prolene suture placed into healthy aorta. Unacceptable endpoints after renal endarterectomy are best treated with conversion to a bypass.

Inadequate Distal Endarterectomy Endpoint Plaque extending to the infrapancreatic SMA may be difficult to entirely remove with standard thoracoabdominal exposure. Intraoperative duplex can confirm an adequate endpoint, and if there is any uncertainty, the abdominal cavity can be entered and the SMA exposed by dividing the ligament of Treitz. This maneuver will provide exposure of the SMA as it emerges from behind the pancreas, usually at a place distal to the diseased segment. Inspection by palpation or with duplex ultrasound can evaluate the repair. Incomplete endarterectomy or intimal flaps can be managed through an arteriotomy at this location. A reasonably sized SMA can be transected and the retained plaque removed; reapproximation with interrupted sutures will secure the intima distal to the endarterectomy. Exposing the endpoint in a smaller vessel is most safely performed with a lateral arteriotomy and subsequent patch angioplasty closure to prevent narrowing. Problematic endarterectomy endpoints in the celiac artery or renal arteries may be best managed with placement of a bypass graft. Conversion to bypass will require enough exposure of the target vessel to allow for revascularization distal to the diseased segment. Either end-to-end or end-to-side reconstruction

is acceptable and should be performed, making certain that the intima is secured with the suture line.

REFERENCES 1. Leather RP, Shah DM, Kaufman JL, et al. Comparative analysis of retroperitoneal and transperitoneal aortic replacement for aneurysm. Surg Gynecol Obstet. 989;168(5):387-393. 2. Mell MW, Acher CW, Hoch JR, et al. Outcomes after endarterectomy for chronic mesenteric ischemia. J Vasc Surg. 2008;48(5):1132-1138. 3. Kasirajan K, O’Hara PJ, Gray BH, et al. Chronic mesenteric ischemia: open surgery versus percutaneous angioplasty and stenting. J Vasc Surg. 2001;33(1):63-71. 4. Rapp JH, Reilly LM, Qvarfordt PG, et al. Durability of endarterectomy and antegrade grafts in the treatment of chronic visceral ischemia. J Vasc Surg. 1986;3(5):799-806. 5. Weibull H, Bergqvist D, Bergentz SE, et al. Percutaneous transluminal renal angioplasty versus surgical reconstruction of atherosclerotic renal artery stenosis: a prospective randomized study. J Vasc Surg. 1993; 18(5):841-850; discussion 850-842.

Chapter 16 Hybrid Revascularization Strategies for Visceral/Renal Arteries Benjamin W. Starnes

DEFINITION The term “hybrid” in vascular surgery traditionally refers to the use of both traditional open surgical and endovascular techniques for remedy of the vascular condition (FIG 1). Two hybrid approaches are described in this chapter. Complete visceral debranching and endovascular tube graft repair Partial visceral debranching and physician-modified fenestrated endovascular repair

DIFFERENTIAL DIAGNOSIS Paravisceral aortic aneurysms may develop due to the following conditions: Degenerative aneurysm Aortic dissection Mycotic aneurysm Paraanastomotic juxtarenal aneurysm Connective tissue disorders (Marfan’s syndrome) Behçet syndrome

PATIENT HISTORY AND PHYSICAL FINDINGS The majority of patients are asymptomatic and the diagnosis is made with imaging done for other reasons. Some patients will complain of mild to moderate abdominal and low back pain. Severe and unrelenting pain should raise the index of suspicion for a mycotic process which, if confirmed, would make hybrid approaches prohibitive.

IMAGING AND OTHER DIAGNOSTIC STUDIES Contrast-enhanced, axial thin-slice computed tomography arteriography (CTA) is the current standard for imaging paravisceral aneurysms. Detailed information can be gathered regarding the precise origin of the celiac, superior mesenteric artery (SMA), and renal arteries (FIG 2). Other important findings on CTA should be as follows: Size and quality of access vessels for delivery of endovascular devices (>7 mm) Location of left renal vein Aberrant anatomy (e.g., replaced right hepatic artery) Quality of gastroduodenal artery for possible celiac artery ligation or sacrifice Renal cortical thickness

SURGICAL MANAGEMENT Indications for repair include aortic aneurysms of more than 5.5 cm, symptoms, or evidence of rapid expansion (>0.5 cm per 6 months).

Preoperative Planning As formal open repair would often include a bicavitary incision (chest and abdomen, as in a formal thoracoabdominal repair), the standard preoperative assessment should focus on the patient’s fitness to undergo major vascular surgery. This includes assessment of heart, lung, and kidney function and reserve.

FIG 1 • “Hybrid repair” refers to the use of both traditional open surgical and endovascular techniques to manage the same problem. SMA, superior mesenteric artery. A. Intraoperative photo. B. Post operative CTA after completed repair. P.129

FIG 2 • CTA axial images depicting (A) a 7.4-cm paraanastomotic juxtarenal aortic aneurysm and (B) a healthy aortic segment in the region of the SMA.

Positioning Proper and precise positioning should be as follows (FIG 3): Patient supine on standard operating room table or imaging table Hair properly clipped over entire abdomen and both groins Both arms tucked (option to have right arm at 90 degrees if planning brachial access) Foley under one leg and padded

FIG 3 • Depiction of positioning and intended incision in the midline.

COMPLETE VISCERAL DEBRANCHING AND ENDOVASCULAR TUBE GRAFT REPAIR— STAGE 1 First Step—Exposure Standard midline laparotomy and positioning of retractor system Upon entry into the abdomen, the falciform ligament is divided between clamps and ligated. The triangular ligaments above the liver are divided to facilitate adequate exposure/retraction while minimizing risk of hepatic capsular injury, anticipating systemic anticoagulation later in the procedure. A nasogastric tube is positioned in the stomach to provide temporary decompression. The common hepatic artery is identified following division of the gastrohepatic ligament and traced back to origin of celiac artery. Once identified, the target artery is encircled with a silastic vessel loop. Space is created along the left side of the aorta with blunt/finger dissection, beginning at the level of the celiac artery, to create the retrograde bypass tunnel posterior to the pancreas (FIG 4).

The colon and omentum are lifted in a cephalad direction, the small bowel swept to the patient’s right and packed in moist towels. Self-retaining retractors (Omni or Bookwalter) should be positioned at this juncture to maintain exposure, with care taken to appropriately pad the retractor blades as necessary. The third and fourth portions of the duodenum are mobilized to the right following division of the ligament of Treitz, exposing the anterior surface of the aorta. The inferior mesenteric vein is ligated and divided as well and the dissection continued along the proximal aorta until the left renal vein is clearly identified (FIG 5). Widely mobilize the left renal vein sharply and encircle with a moist umbilical tape. The self-retaining renal vein retractor blade is used to retract the left renal vein cephalad as necessary to facilitate further exposure. The origin of the renal arteries is identified by careful posterolateral dissection around the aorta, just cephalad of the overlying renal vein. Exposure on the right is complicated somewhat by the overlying inferior vena cava/left renal vein confluence. At least 2 cm of renal artery should be exposed bilaterally. Encircle the renal arteries with silastic vessel loops. On the left, finger dissect bluntly along the aorta in a cephalad fashion to complete the retropancreatic tunnel for the celiac limb of the bypass graft. The SMA is identified next by palpation within the base of the small bowel mesentery, directly anterior to the pancreas. Doppler ultrasonography may assist identification when the pulse is faint. Once identified, a 3-cm segment of SMA is isolated as proximal as possible to the root of the mesentery. Beginning with the middle colic artery, multiple mesenteric arteries quickly branch from the SMA as it emerges from the pancreas, underscoring the need for proximal identification and isolation. The SMA is controlled with vessel loops. P.130 The next step is to prepare the donor artery for hybrid bypass. The specific artery—most commonly the common or external iliac arteries—should be selected from the preoperative imaging study. The retroperitoneum is opened directly over the selected donor artery, which is exposed while protecting the adjacent ureter. Alternatively, donor artery exposure may be achieved via medial-visceral rotation, developing the entire retroperitoneal plane on the left. The latter approach provides the added benefit of exclusion of the graft from the viscera and abdominal contents once the viscera are returned to their original position. This maneuver adds significantly more time to P.131 the case, however, and contributes to increased blood loss. Graft coverage can also be obtained without developing the entire retroperitoneal plane, either via direct tunneling along the preferred course of the graft or creation of an omental tongue affixed directly to the graft.

FIG 4 • Drawing of exposure of the celiac artery through the lesser sac. Note the blunt finger dissection along the left side of the aorta and behind the pancreas.

FIG 5 • Drawing of exposure of the left renal vein and anterior surface of the aortic aneurysm. Dashed line depicts intended incision line to avoid nervi erigentes.

Second Step—Anticoagulation Systemic anticoagulation is achieved with a bolus injection of unfractionated heparin, 50 units/kg. Monitoring activated clotting time is a useful method of maintaining adequate anticoagulation during the procedure.

Third Step—Multivisceral Bypass Trifurcated grafts exist for the purpose of facilitating multivessel hybrid revascularization, but the use of these are limited by the tendency of the middle limb to occlude when “squeezed” between the outside limbs during graft routing and abdominal closure. In most circumstances, a standard 12 × 7 bifurcated, collagen-impregnated knitted polyester graft provides excellent conduits for bilateral renal revascularization, with a separate 8-mm limb connected to the celiac and SMA. Examples of bypass graft configurations are shown in FIGS 6 and 7. The proximal (iliac/inflow) anastomosis is completed first with running 4-0 or 5-0 polypropylene suture. The next anastomosis to be completed should be one anticipated to be the technically most difficult, given exposure and graft routing issues. Most commonly, this is the right renal artery. This is divided following placement of a large clip at the origin. The appropriate graft limb is pulled to length and anastomosed end-to-end with 5-0 polypropylene suture. The limb and artery are flushed just prior to completion of the graft, after which the clamps are released to reperfuse the kidney. Following this

sequence, warm renal ischemia time is generally less than 12 minutes. The stump of the right renal artery is then suture ligated; avoid clip dislodgement. Note: Excessive traction on the confluence of the left renal vein and vena cava may cause caval injury and massive hemorrhage during preparation and completion of the right renal artery anastomosis. Retractor positioning needs to account for potential venous injury during exposure and significantly relaxed following completion of the anastomosis. The left renal anastomosis is completed in nearly identical fashion, minus many of the exposure limitations present on the right. The SMA graft is carefully sized to length so that it follows a “C”-shaped configuration without kinking. Inflow can be obtained either from the many bodies of the graft or either of the completed renal limbs. The SMA-graft anastomosis is completed end-to-side with interrupted or running 5-0 polypropylene suture. The end-to-side arteriotomy length is 1.5 to 2 times the width of the bypass graft (12 to 16 mm). Alternatively, end-to-end anastomotic configuration may reduce the likelihood of graft kinking depending on final configuration. Following completion of the anastomosis, the proximal SMA is ligated with a large clip or circumference suture. Again, ischemia time should be under 10 to 12 minutes. Typically, following SMA and renal graft completion, repositioning of the retraction system is necessary to reobtain and optimize celiac artery exposure. Prior to reexposing P.132 the celiac, a vascular clamp is repassed through the retropancreatic tunnel left of the aorta. This position is then maintained until the transverse colon and mesocolon are reduced to their usual location. This reexposes the “looped” celiac and common hepatic arteries previously isolated in the lesser sac. The clamp tip exiting the retrohepatic tunnel is identified, and a moist umbilical tape is pulled through the tunnel. Following this, the celiac limb is tied to the umbilical tape, which is then pulled cephalad behind the pancreas and into position for either endtoend or end-to-side anastomosis. Care again needs to be taken to optimize limb routing and length to minimize risk for kinking. After coverage of remaining exposed graft limbs with omentum or parietal peritoneum as appropriate, standard abdominal closure is performed.

FIG 6 • Drawing of a four-vessel debranching based off of the left common iliac artery. Note that the left renal vein was divided in this case, and subsequently repaired, for better exposure of the renal arteries.

FIG 7 • Aortobiiliac and subsequent debranching for a patient with a solitary left kidney and infrarenal aneurysm.

COMPLETE VISCERAL DEBRANCHING AND ENDOVASCULAR TUBE GRAFT REPAIR— STAGE 2 First Step—Percutaneous Access Following the “debranching” procedure described in stage 1, endovascular aneurysm repair (EVAR) may be performed either at the same setting or within several weeks of the initial procedure. The risk of potential aneurysm rupture associated with a staged approach needs to be balanced with the additional operative risk inherent in the longer anesthetic time required to complete both stages in one sitting. For the EVAR procedure itself, standard percutaneous access to an appropriately sized access vessel is obtained using Seldinger technique and a wire advanced into the aorta under fluoroscopic guidance. In our practice, this is most commonly obtained percutaneously, using ultrasound guidance and

preplacement of polypropylene suture prior to dilation of the access sites (also known as the “preclose” Perclose® technique (Abbott Vascular Inc, Redwood City, CA).1 An 11-Fr standard sheath is placed into the common femoral artery and flushed with heparinized saline. Wire advancement from the femoral artery to the aortic arch must be visualized radiographically throughout its course, as the wire may preferentially enter the debranching graft and cause end-organ injury or hemorrhage without real-time position monitoring and guidance.

Second Step—Stiff Wire Exchange After wire advancement to the transverse aortic arch, standard wire exchange technique is used to position a 0.035-in stiff (e.g., Lunderquist®, Cook Medical, Bloomington, IN) wire through the abdominal and thoracic aorta. Optimal final wire positioning is at/just distal to the left subclavian artery orifice.

Third Step—Intravascular Ultrasound An 8.2-Fr Visions® catheter (Volcano Therapeutics, Irvine, CA) is used to confirm appropriate proximal and distal landing zones for endovascular graft placement. The optimal graft size and configuration is determined by analysis of CTA images reformatted and visualized on a dedicated 3-D image workstation (AquariusNet®, TeraRecon, Inc, San Mateo, CA). Graft diameter should be oversized by 10% to 15% for this application. During advancement of the device, the origin of the debranching graft can also be visualized either through fluoroscopic confirmation of a metallic clip placed during the debranching procedure or under intravascular ultrasound (IVUS) real-time guidance. Using IVUS, the position of the IVUS catheter is marked on the fluoroscopic monitor when the catheter itself recognizes the orifice of the debranched graft. Alternatively, a contrast power injection can be performed through an appropriately positioned arteriographic catheter with 30 mL of contrast injected at 15 mL per second to confirm the proximal and distal landing zones.

Fourth Step—Endograft Deployment The endovascular graft is deployed following devicespecific instructions for use (IFU), covering the native origins of the visceral vessels and excluding the aortic aneurysm. The femoral arteriotomy is then closed.

PARTIAL VISCERAL DEBRANCHING AND PHYSICIAN-MODIFIED ENDOVASCULAR REPAIR —STAGE 1 First Step—Exposure Standard midline laparotomy and positioning of retractor system. Upon entry into the abdomen, the falciform ligament is divided between clamps and ligated. The triangular ligaments above the liver are divided to facilitate adequate exposure/retraction while minimizing risk of hepatic capsular injury, anticipating systemic anticoagulation later in the procedure. A nasogastric tube is positioned in the stomach to provide temporary decompression. The common hepatic artery is identified following division of the gastrohepatic ligament and traced back to origin of celiac artery. Once identified, the target artery is encircled with a silastic vessel loop. Space is created along the left side of the aorta with blunt/finger dissection, beginning at the level of the celiac artery, to create the retrograde bypass tunnel posterior to the pancreas. The colon and omentum are lifted in a cephalad direction, the small bowel swept to the patient’s right and P.133 packed in moist towels. Self-retaining retractors (Omni or Bookwalter) should be positioned at this

juncture to maintain exposure, with care taken to appropriately pad the retractor blades as necessary. The third and fourth portions of the duodenum are mobilized to the right following division of the ligament of Treitz, exposing the anterior surface of the aorta. The inferior mesenteric vein is ligated and divided as well and the dissection continued along the proximal aorta until the left renal vein is clearly identified. Widely mobilize the left renal vein sharply and encircle with a moist umbilical tape. The self-retaining renal vein retractor blade is used to retract the left renal vein cephalad as necessary to facilitate further exposure. The origin of the renal arteries is identified by careful posterolateral dissection around the aorta, just cephalad of the overlying renal vein. Exposure on the right is complicated somewhat by the overlying inferior vena cava/left renal vein confluence. At least 2 cm of renal artery should be exposed bilaterally. Encircle the renal arteries with silastic vessel loops. On the left, finger dissect bluntly along the aorta in a cephalad fashion to complete the retropancreatic tunnel for the celiac limb of the bypass graft. The SMA is identified next by palpation within the base of the small bowel mesentery, directly anterior to the pancreas. Doppler ultrasonography may assist identification when the pulse is faint. Once identified, a 3-cm segment of SMA is isolated as proximal as possible to the root of the mesentery. Beginning with the middle colic artery, multiple mesenteric arteries quickly branch from the SMA as it emerges from the pancreas, underscoring the need for proximal identification and isolation. The SMA is controlled with vessel loops. The next step is to prepare the donor artery for hybrid bypass. The specific artery—most commonly the common or external iliac arteries—should be selected from the preoperative imaging study. The retroperitoneum is opened directly over the selected donor artery, which is exposed while protecting the adjacent ureter. Alternatively, donor artery exposure may be achieved via medial-visceral rotation, developing the entire retroperitoneal plane on the left. The latter approach provides the added benefit of exclusion of the graft from the viscera and abdominal contents once the viscera are returned to their original position. This maneuver adds significantly more time to the case, however, and contributes to increased blood loss. Graft coverage can also be obtained without developing the entire retroperitoneal plane, either via direct tunneling along the preferred course of the graft or creation of an omental tongue affixed directly to the graft.

Second Step—Anticoagulation Systemic anticoagulation is achieved with a bolus injection of unfractionated heparin, 50 units/kg. Monitoring activated clotting time is a useful method of maintaining adequate anticoagulation during the procedure.

Third Step—Multivisceral Bypass Trifurcated grafts exist for the purpose of facilitating multivessel hybrid revascularization, but the use of these are limited by the tendency of the middle limb to occlude when squeezed between the outside limbs during graft routing and abdominal closure. In most circumstances, a standard 12 × 7 bifurcated, collagen-impregnated knitted polyester graft provides excellent conduits for bilateral renal revascularization, with a separate 8-mm limb connected to the celiac and SMA. Examples of bypass graft configurations are shown in FIGS 6 and 7. The proximal (iliac/inflow) anastomosis is completed first with running 4-0 or 5-0 polypropylene suture. The next anastomosis to be completed should be one anticipated to be the technically most difficult, given exposure and graft routing issues. Most commonly, this is the right renal artery. This is divided following placement of a large clip at the origin. The appropriate graft limb is pulled to length and anastomosed end-to-end with 5-0 polypropylene suture. The limb and artery are flushed just prior to

completion of the graft, after which the clamps are released to reperfuse the kidney. Following this sequence, warm renal ischemia time is generally less than 12 minutes. The stump of the right renal artery is then suture ligated; avoid clip dislodgement. Note: Excessive traction on the confluence of the left renal vein and vena cava may cause caval injury and massive hemorrhage during preparation and completion of the right renal artery anastomosis. Retractor positioning needs to account for potential venous injury during exposure and significantly relaxed following completion of the anastomosis. The renal anastomosis is completed in nearly identical fashion, minus many of the exposure limitations present on the right.

PARTIAL VISCERAL DEBRANCHING AND PHYSICIAN-MODIFIED ENDOVASCULAR REPAIR —STAGE 22 First Step—Creation of a Fenestrated Graft for the Celiac and Superior Mesenteric Artery The appropriate endovascular device is chosen according to standard IFU sizing guidelines, typically incorporating 10% to 15% oversizing. The sterile graft is unsheathed on a dedicated sterile table in the operating room and marked with the relative locations (length from proximal end and clockface measurements) of the celiac and SMA fenestrations as previously determined via TeraRecon ® workstation analysis. Minor adjustments are allowed to minimize strut overlap of planned fenestration locations. Fenestrations in the polyester endograft fabric are created with a disposable ophthalmic cautery to minimize fraying. The fenestrations are outlined and reinforced with 15-mm gold Amplatz Gooseneck® P.134 snares (ev3 Endovascular, Inc, Plymouth, MN). These are hand sewn into place using 4-0 Prolene suture in a double row circumferentially (FIG 8). Diameter-reducing ties were then used to constrain the device along its posterior border (opposite the SMA and or celiac fenestration at 6 o’clock) by rerouting the existing proximal trigger wire through and through the graft material at the midportion of each of the top two Z stents. The constraining ties are then tied down into place over the trigger wire. The entire graft is then wetted with heparinized saline and then reloaded into the existing sheath.

FIG 8 • Photograph of a thoracic endograft with two fenestrations created for the celiac (struts present) and SMA (strut free), prior to resheathing and deployment.

Second Step—Percutaneous Access Standard percutaneous access to an appropriately sized access vessel is obtained using Seldinger technique. The initial guidewire is advanced into the aorta under fluoroscopic guidance. In our practice, this is most commonly obtained percutaneously, using ultrasound guidance and preplacement of

polypropylene suture prior to dilation of the access sites (also known as the “preclose” Perclose® technique (Abbott Vascular Inc, Redwood City, CA).1 An 11-Fr standard sheath is placed into the common femoral artery and flushed with heparinized saline. Wire advancement from the femoral artery to the aortic arch must be visualized radiographically throughout its course, as the wire may preferentially enter the debranching graft and cause end-organ renal injury, rupture of Gerota’s fascia, and retroperitoneal hemorrhage without real-time position monitoring and guidance.

Third Step—Stiff Wire Exchange A standard 4- or 5-Fr catheter is used to perform a wire exchange to a stiff 0.035-in Lunderquist® wire (Cook Medical, Bloomington, IN). The wire is positioned so that its tip is just distal to the left subclavian artery.

Fourth Step—Marking of the Target Vessels and Graft Deployment A contrast power injection can be performed with 10 mL of contrast injected at 25 mL per second to mark the precise origins of the celiac and SMA (FIG 9). The modified graft is positioned over the target vessels, oriented, and deployed.

Fifth Step—Cannulation of the Target Vessels An 18-Fr sheath is advanced from the contralateral groin and into the distal graft over a stiff wire. Two 7Fr Raabe® sheaths (Cook Medical, Bloomington, IN) are advanced together through the 18-Fr sheath. Working through these sheaths, the SMA and celiac vessels are selected through the fenestrations using standard catheter and guidewire techniques, with the sheaths ultimately advanced into the target vessels over stiff wires. After sheath advancement and confirmation of target vessel acquisition, the main body is distended flush with the surrounding aorta with a moulding balloon (e.g., Coda®, Cook Medical, Bloomington, IN). This inflation represents the final opportunity to distend the endograft in the region of the visceral stents. Lateral positioning of the image intensifier guides stent placement into the SMA and celiac arteries (typically 8- to 9-mm stents; FIG 10). FIG 11 shows follow-up computed tomography (CT) imaging of a patient 1 year after successful treatment with this technique.

FIG 9 • Note the double densities depicting the origins of the celiac and SMA on this flush aortogram.

Sixth Step—Access Site Closure The access sites are closed with the previously placed sutures.

FIG 10 • Lateral image depicting placement of a covered balloon-expandable stent into the SMA prior to deployment. P.135

FIG 11 • A,B. Follow-up CT images of a patient successfully treated with partial visceral debranching and physician-modified endovascular fenestrated repair.

PEARLS AND PITFALLS Choice of operating room (OR) table

▪Use standard OR tables for open surgical procedures and imaging tables for image-guided or hybrid procedures. Advanced planning is essential to optimize outcome. Never sacrifice exposure!

Exposure of common iliac artery

▪Identify and protect the ureter.

Placement of wires after debranching procedure

▪ Pass guidewires under continuous fluoroscopic guidance following debranching. An advancing aortic wire may preferentially enter and traverse the debranching graft, causing end-organ injury, disorientation, and possible endograft maldeployment if not recognized.

Timing of stent graft balloon

▪ Always seat the endograft with balloon inflation prior to placement of visceral bridging stents. Instrumentation or distention of the fenestrated endograft

moulding during fenestrated EVAR

following branch vessel stenting may compromise stent positioning, integrity, and patency.

POSTOPERATIVE CARE Open aortic debranching procedures are not benign; almost all patients will require intensive care postprocedure. Spinal drainage is used selectively for aortic coverage extending more than 10 cm cephalad to the celiac artery. Postoperative anuria or persistent acidosis/rising lactate require immediate investigation to prove branch vessel patency.

OUTCOMES Contemporary hybrid debranching procedures for complex abdominal aortic aneurysmal disease are associated with a 13% operative mortality rate, 2% permanent paraplegia rate, and 1% stroke rate.3 Hybrid approaches offer the advantage of versatility, avoidance of extensive operative exposures, and potentially offer a broader range of therapies to a patient population that would not otherwise be considered for aortic surgical repair.

COMPLICATIONS Access-related complications Hemorrhage requiring transfusion Paraplegia Stroke Renal failure Death

REFERENCES 1. Starnes BW, Andersen CA, Ronsivalle JA, et al. Totally percutaneous aortic aneurysm repair: experience and prudence. J Vasc Surg. 2006;43(2):270-276. 2. Starnes BW, Quiroga E. Hybrid-fenestrated aortic aneurysm repair: a novel technique for treating patients with para-anastomotic juxtarenal aneurysms. Ann Vasc Surg. 2010;24(8):1150-1153. 3. Starnes BW, Tran NT, McDonald JM. Hybrid approaches to repair of complex aortic aneurysmal disease. Surg Clin North Am. 2007;87(5):1087-1098, ix.

Chapter 17 Snorkel/Chimney and Periscope Visceral Revascularization during Complex Endovascular Aneurysm Repair Jason T. Lee Ronald L. Dalman

DEFINITION Although routine endovascular aneurysm repair (EVAR) has gained widespread acceptance as the procedure of choice for patients with suitable aortic neck anatomy, the optimal approach to the juxtarenal aortic aneurysm (JAA), often with challenging anatomy at the visceral neck, remains controversial. 1 Although open repair is an effective and durable option for patients with JAA, particularly in centers of excellence for low physiologic risk patients,2 endovascular techniques including fenestrated and branched EVAR (FBE) have emerged as effective, potentially less invasive alternatives.3 In the United States, however, lack of widespread availability of FBE has allowed other techniques to emerge, and in this chapter, we describe the increasingly popular “snorkel” or “chimney” technique, defined as a parallel stent graft adjacent to the endograft main body to maintain perfusion to renal and visceral branches during EVAR and placed from a cranial direction, and the “periscope” technique, where the parallel stent graft is placed from the caudal direction. First described by Greenberg and associates,4 the snorkel strategy can be employed either as a bailout from accidental coverage of vital side branches during deployments requiring close approximation of the main body to the branch artery in question, or the intentional cranial relocation of the EVAR seal zone for JAAs.5,6,7,8

DIFFERENTIAL DIAGNOSIS The challenge for the vascular specialist in treating JAAs revolves around an increasing number of choices for intervention, including traditional suprarenal repair, hybrid type debranching procedures, fenestrated and branched devices in clinical trials or certain centers, and snorkel/chimney/periscope techniques. The choice is most often based on patient physiologic parameters, physician experience with the multitude of techniques, and a very individualized approach to complex aortic anatomy.

PATIENT HISTORY AND PHYSICAL FINDINGS Most patients present electively and essentially without symptoms for consideration of repair of their JAA, as it is most often discovered during radiographic workup for vague abdominal discomfort, back pain, or as part of a screening program. A pulsatile, nontender abdominal mass can be elicited on careful abdominal exam. Any signs of persistent abdominal or back pain or hemodynamic instability or compromise should suggest the possibility of an acute aortic pathology and prompt more urgent workup and treatment. Careful attention during the history and physical examination to cardiac and renal comorbidities aids in risk-stratifying the patient for potential repair of their JAA. Because most patients are asymptomatic and aneurysms are repaired to prevent future rupture, some reasonable quality of life must be present for the patient to enjoy the survival advantage.

IMAGING AND OTHER DIAGNOSTIC STUDIES

High-quality computed tomography angiography (CT-A) on a modern 64-slice scanner able to produce at least 2-mm-thin cuts is a requirement for treatment with snorkel techniques. These imaging algorithms allow the creation of virtual models of the aneurysm for the surgeon to better appreciate the relationship of branches and potential areas of technical challenge (FIG 1). Patients with compromised kidney function who cannot undertake iodinated contrast are poor candidates for snorkel procedures, as noncontrast scans fail to elucidate thrombus volume, branch artery patency, and luminal diameter in the preoperative planning that is paramount to success. Access to a three-dimensional (3-D) workstation/program and familiarity with reconstruction software by the implanting surgeon for manipulation of the images and creating centerline pathways should be mandatory to most accurately plan device orientation, selection, and sizing (FIG 2). Because the snorkel technique usually involves access of the brachial artery for delivery of the parallel visceral stent grafts, visualization of the arch and proximal subclavian is P.137 most conveniently obtained by including the chest in the standard CT-A of the abdomen and pelvis. The presence of a challenging type III arch, where the subclavian inserts below the inner curve of the aortic arch, makes the procedure more challenging and many times prohibitive due to concerns about arch manipulation, cerebral emboli, and deliverability of stent grafts (FIG 3). If the patient has already undergone an adequate CT-A abdomen and pelvis and one wishes to avoid the additional contrast load of repeating the study, a noncontrast chest computed tomography (CT) can be performed to visualize the arch but then should be combined with arterial duplex and waveforms of the upper extremities to ensure patency of the axillosubclavian arterial system. For patients with chronic kidney disease, high-grade renal stenosis, atretic kidneys, or multiple visceral and renal vessels involved in the endovascular plan for snorkeling, nuclear medicine split renal function tests can help determine if it is reasonable to sacrifice one of the renal arteries. This can be done in order to simplify the snorkel strategy and keep the number of cranially oriented stent grafts to two, which may have an influence on overall morbidity and mortality from the procedure.1,7,8

FIG 1 • 3-D reconstruction of juxtarenal aneurysm with infrarenal neck length of 5 mm.

FIG 2 • TeraRecon workstation view highlighting ability to manipulate images in multiple user-defined planes.

FIG 3 • Type III aortic arch with origin of subclavian artery being lower than inner curve of aortic arch. The ability to advance a snorkel sheath from the left arm is severely compromised in this configuration and generally not recommended if alternative repair methods are available.

SURGICAL MANAGEMENT Preoperative Planning All patients considered for snorkel/chimney or periscope techniques should have undergone an extensive informed consent discussion related to off-label use of endograft components for treatment of their complex aneurysm. Alternatives often discussed include open surgery with suprarenal clamping, hybrid debranching, referral to a center with access to fenestrated or branched devices, or no surgery at all. Once the decision is made to proceed with the snorkel strategy, we prefer a twosurgeon approach with one performing the femoral access portion and one the brachial access portion. Both surgeons should have reviewed on the 3-D workstation the anatomy, the endovascular plan, and the sequence for deployment. Access to a hybrid endovascular suite is highly recommended, although not mandatory, for successful completion of these procedures. Fixed imaging provides improved accuracy, reliability, and reproducibility of the anatomy throughout the sequence of the snorkel procedure. Knowledgeable operating room and cathangio staff should be assigned to these cases and available endografts and wires/catheters as well as backups should all be arranged ahead of time to provide the safest working environment for the patient as well

as the operative team. Choosing the main body endograft, its configuration, and size has been described by numerous authors who all report excellent results overall with a wide variety of devices and formulas.9 In general, we often “oversized” to about 25% to 30% instead of the typical 15% to 20% for standard EVAR to account for the additional fabric infolding to accommodate the snorkel stent(s). Given the amount of dye often used as well as renal artery manipulation during the most complex of snorkel cases, we prefer to admit the patient the evening before or several hours prior to surgery for additional intravenous hydration when possible. General anesthesia is preferred, with consideration for preoperative lumbar drainage based on risk of spinal cord ischemia. Arterial monitoring, when necessary, is achieved via the right arm. Adequate venous access can consist of either largebore peripheral intravenous lines (IVs) or a central line. There is usually not a need for autotransfusion or cell saver setups unless an iliac or axillary conduit is planned where there is more potential for early blood loss during the procedure.

Positioning The hybrid room can be set up as either “head” position (FIG 4) or “right side, table rotated” depending on the type of imaging equipment. With the right arm tucked, the left arm is prepped circumferentially and placed on an armboard at about 75 to 90 degrees while the chest and abdomen down to the groins are prepped. Surgeon A, who will stand at the patient’s right hip, has control of the C-arm and imaging functions and is in charge of obtaining femoral access and delivery of devices from the groins. Surgeon B stands above the outstretched left arm, with an additional sterile table extending off the left hand to allow for wires and catheters to remain sterile and available for arm access during the procedure. The monitor is placed at a slight angle toward the foot of the bed to allow both surgeons to visualize, or a slave monitor can be employed. P.138

FIG 4 • Endovascular suite setup for snorkel/chimney EVAR with left arm prepped and outstretched, C-arm at

right-sided/table rotated position to allow for lateral imaging, and monitors at foot of bed. Surgeon A stands at patient’s right hip and controls C-arm. Surgeon B stands above patient’s left arm to deliver wires and catheters from side table.

SNORKEL/CHIMNEY ENDOVASCULAR ANEURYSM REPAIR Arm Access A 5-cm transverse incision slightly below the left axilla over the palpable brachial pulse affords several centimeters of longitudinal exposure of the high brachial artery (FIG 5A). Staying proximal to the deep brachial artery takeoff allows a large enough caliber of brachial artery for typical delivery of two 7-Fr sheaths for a double renal snorkel procedure. At least 7 to 8 cm of healthy brachial artery should be dissected free and slung with vessel loops to allow accurate puncture of the vessel. The two punctures should be placed at least 2 cm apart, and not next to each other, to facilitate later simpler, individual primary closure. For cases when larger delivery sheaths may need to be inserted or in cases where potentially up to three or four snorkel stents need delivery, then an infraclavicular incision and exposure of the axillary artery for possible 10-mm Dacron conduit placement is recommended (FIG 5B). When this is planned, a 20-Fr or 22-Fr sheath can be inserted to get around the arch and then three 6-Fr or 7-Fr sheaths can be used to cannulate the visceral vessels. For the simplest of all snorkel cases, when just one renal artery needs stenting, a lower brachial incision can be made to allow insertion of a single 7-Fr sheath (FIG 5C).

Renal/Visceral Cannulation and Sheath Advancement A 5-Fr micropuncture access is obtained under direct visualization into the brachial artery. A Bentson wire is advanced, under fluoroscopic guidance, most often into the ascending aorta. The use of an Omniflush catheter and glidewire (either a 260-cm Rosen or Amplatz [Cook Medical, Bloomington, IN]) combination, to direct the wire toward the visceral aorta, allows a wire exchange for a stiffer platform. Over this stiffer platform, two 7-Fr 90-cm Pinnacle Destination sheaths (Terumo Medical, Somerset, NJ) are positioned near the visceral target branches to facilitate cannulation attempts (FIG 6A). Through the 7-Fr sheaths, the targeted renal and visceral branches are cannulated using 260-cm-length hydrophilic guidewires and a 125-cm JB1 catheter (Cook Medical, Bloomington, IN). An angiographic run can be performed from a flush catheter advanced from femoral access to aid in renal cannulation (FIG 6B). Thorough knowledge of the preoperative anatomy, derived from reformatting from the 3-D workstation facilitates P.139 this portion of the procedure, guiding optimal angulation of the C-arm. Once cannulated, the sheaths are advanced coaxially into the target artery orifice. When necessary, or in cases where there is a slight turn to the horizontal rather than downward angled, the soft hydrophilic guidewire needs to be exchanged for a 260-cm J-tip Rosen wire (Cook Medical, Bloomington, IN) or Amplatz Superstiff (1-cm tip) to facilitate sheath advancement into the target renal artery. Confirmation angiography, through the sheath, is performed to ensure patency of the renal arteries, cannulation of the main renal artery, and avoidance of accidental side branch cannulation.

Positioning of Main Body Endograft and Snorkel Stent Grafts Standard femoral access for EVAR is employed for snorkel technique. This is well described in other chapters. Briefly, a small transverse incision, below the inguinal ligament, can be used to expose the common femoral artery to the bifurcation for delivery of endograft components. The percutaneous

approach involves the “preclose” technique and employs two Perclose ProGlide devices (Abbott Vascular, Santa Clara, CA) oriented at 10 o’clock and 2 o’clock positions.10 The main body endograft can then be delivered up the chosen femoral side to the paravisceral aorta at the same time as the iCAST (Atrium Medical, Hudson, NJ) or Viabahn (Gore Medical, Flagstaff, AZ) stents are advanced through the snorkel sheaths out to the target renal arteries (FIG 7A). The typical length of the iCAST is 59 mm, with the diameter sized appropriately to seal in the target renal artery, most often 5, 6, or 7 mm. For Viabahn stents, similar diameters are used in 50- or 100-mm lengths as appropriate. To prevent theoretical compression of the Viabahn stent by the main body of the endograft, the Viabahn can be reinforced from the inside with a baremetal, balloon-expandable stent along the areas of overlap with the main body. The positioning of the snorkel stent requires that at least 10 mm of fixation into the renal artery be present and that the proximal extent of the graft is above the fabric of the main body endograft. In a lateral projection angiography, the superior mesenteric artery (SMA) is visualized (when performing the typical double renal snorkel) and the main body fabric edge placed immediately below the origin of the SMA (FIG 7B). P.140 At this point, final small adjustments can be made as well as further angiography to ensure that the snorkel stents are in good position. To avoid the issue of the iCAST stent being unstable off its balloon, we often leave the 7-Fr sheaths in place to protect them until final deployment.

FIG 5 • A. Skin incision via a high brachial incision near the axilla exposes the proximal brachial artery, often giving adequate size for double puncture. B. Infraclavicular incision to expose the axillary artery necessary when three or four snorkel/chimney sheaths needed. A 10-mm or 12-mm Dacron conduit can be sewn into the axillary artery in this position. C. Small incision over palpable brachial artery near antecubital crease can

be used when only single snorkel/chimney sheath necessary.

FIG 6 • A. Two 7-Fr Terumo sheaths placed from arm access down descending thoracic aorta ready to be positioned near visceral aortic region. B. Right renal artery cannulated with glidewire and JB1 catheter. Omniflush catheter from below reveals in an angiogram the position of the left renal artery to be cannulated next.

FIG 7 • A. In the anterior-posterior view, both snorkel iCAST stents in position from arm approach along with

main body endograft being put into position. B. Lateral view angiogram shows takeoff of SMA (red arrow) and positioning of the main body endograft fabric edge (white arrow) immediately below SMA.

FIG 8 • A. Main body endograft deployed in anteroposterior (AP) view with snorkel stents in position. B. After cannulation of contralateral gate and advancement of proximal molding balloon into aortic stent, the two snorkel stents are fully inflated. C. The molding balloon is then maximally inflated to profile and to minimize gutters. D. The molding balloon is completely deflated prior to snorkel stent balloon deflation.

Sequence of Stent Graft Deployment and Balloon Molding The main body endograft is deployed at the target location with its fabric edge being immediately below the SMA edge (FIG 8A). Depending on the endograft system used, deployment proceeds down to the contralateral gate opening. From the contralateral femoral access, cannulation of the gate is confirmed and a noncompliant molding balloon (32- or 40-mm Coda balloon; Cook Medical, Bloomington, IN) is placed up to the level of the renal vessels. The 7-Fr sheaths are slowly withdrawn from the brachial approach so the tip is just proximal to the edge of the renal snorkel stents and deployment of the iCAST occurs, most often simultaneously and to a nominal pressure of eight atmospheres (FIG 8B). At the same time that the iCAST stents are being deployed by balloon inflation, slower inflation of the Coda occurs to slowly mold the main body fabric around the snorkel stents to minimize gutter formation. Only when the renal snorkel stents are maximally inflated can the Coda balloon go up to full main body endograft diameter (FIG 8C). This step cannot be overemphasized, as deflation of the snorkel stents while the Coda is inflated is likely to crush the balloon-expandable covered stents. With the renal snorkel stents still maximally inflated, the Coda balloon can finally be let down after a few seconds of balloon molding to complete the sequence (FIG 8D). After the proximal molding balloon is completely deflated, the renal snorkel balloons are deflated to allow perfusion of the kidneys.

Completion of Distal Components Prior to losing wire access to the renal vessels, a proximal aortogram is performed to look for a large type I endoleak or poor perfusion of either targeted kidney. If this is satisfactory, the distal components of the endograft can be advanced and deployed in the usual fashion. Repair of the access sites, particularly the brachial site, requires careful interrupted 6-0 or 7-0 Prolene sutures, and adequate hand and foot perfusion is verified prior to completion of the case. Postoperative CTA demonstrates the typical appearance of the snorkel stents adjacent to the main body endograft with minimal gutters (FIG 9A), and the 3-D reconstruction shows excellent alignment and

configuration of the snorkel EVAR components (FIG 9B).

FIG 9 • A. Postoperative CTA axial view showing molding of main body endograft around two widely patent snorkel stents. B. 3-D reconstruction demonstrating excellent perfusion of both kidneys and no evidence of endoleak.

P.141

PERISCOPE ENDOVASCULAR ANEURYSM REPAIR/THORACIC ENDOVASCULAR AORTIC REPAIR Femoral Access for Introduction of Main Body Endograft Periscope EVAR/thoracic endovascular aortic repair (TEVAR) builds on the concept above of parallel endografts but places the visceral stents from a femoral approach, requiring blood flow to go through the main body stent graft, then turn around and return cranially to the visceral or renal vessel.11 The femoral access for periscope, in contradistinction to snorkel/chimney strategies, often involves the use of larger caliber thoracic or fenestrated main body components (often 22 Fr to 26 Fr), leading to a slightly higher usage of open or endovascular iliac conduits. One useful modification to an iliac conduit that can be helpful in delivering and torquing large-caliber main body components or sheaths during periscope EVAR/TEVAR involves creating a patch at the distal end (FIG 10). This patch region is created by cutting a 10- or 12-mm Dacron graft along its long access, creating a sewing patch that enlarges the transition from graft to vessel, and not limiting the flexibility of the branch to the initial angle it is sewn into.

Contralateral Access and Cannulation of Target Visceral Branch(es) After the femoral access side has been chosen and prepared for main body endograft delivery, the contralateral femoral site is used to cannulate the planned visceral or renal branches from the bottom. In

the periscope configuration, the parallel stent graft is often required to make a U-turn, so the more flexible covered stent, the self-expanding Viabahn (Gore Medical, Flagstaff, AZ), is preferred. This requires larger sheath access (up to 12 Fr) than the iCAST described earlier; however, for a double periscope configuration, a larger 20-Fr or 22-Fr sheath is usually necessary to perform multiple punctures into (FIG 11). The typical periscope EVAR/TEVAR involves the need for a distal landing zone (FIG 12). In this particular case, the celiac and one renal artery were already occluded, so the periscope technique was used to revascularize the SMA and remaining renal artery, with an 11-mm Viabahn in the SMA requiring a 12-Fr sheath (blue arrow) and an 8-mm Viabahn as the renal periscope requiring an 8-Fr sheath (orange arrow) (FIG 13).

FIG 10 • A. 10-mm Dacron conduit bisected longitudinally to create a sewing patch. B. Dacron iliac conduit sewn to native iliac artery allows easy mobility of the conduit at multiple angles of entry for large-caliber device or sheath. (From Lee JT, Lee GK, Chandra V, et al. Comparison of fenestrated endografts and the snorkel/chimney technique [published online ahead of print April 27, 2014]. J Vasc Surg. doi:10.1016/j.jvs.2014.03.255.)

FIG 11 • 22-Fr sheath with multiple punctures allows three separate 6-Fr sheaths to be inserted without leakage.

Sheath Advancement and Periscope Stent Graft Positioning Similar to the snorkel/chimney EVAR procedure earlier, the general principles of advancing the sheath into the target visceral vessel are repeated, but in periscope EVAR/TEVAR, all is performed from the femoral approach. The SMA and renal periscopes are positioned several centimeters into the target vessel origin, with the distal end (blue arrow) below the bottom end of the main body stent graft (white arrow) (FIG 14).

Sequence of Deployment and Balloon Molding The main body endograft is deployed with the periscope sheaths still in position (FIG 15A). The sheaths are then slowly withdrawn to allow the periscope stent grafts (Viabahns) to deploy against the main body endograft (FIG 15B). Because there is often some compression of the self-expanding periscope stents, an additional balloonexpandable bare stent is placed along where there is contact with the main body endograft and a similar sequence as earlier of balloon molding is performed to minimize gutter formation (FIG 16). The remainder of the proximal aspect of the aneurysm is visualized and appropriately stent grafted with proximal extensions and ballooned (FIG 17), and postoperative CT-A confirms aneurysm exclusion with wide patency of the periscope stent grafts and normal target vessel perfusion (FIG 18).

P.142

FIG 12 • Thoracoabdominal aneurysm formed above prior open repair with occluded right renal and celiac arteries. Periscope configuration to keep SMA and right renal artery perfused.

FIG 13 • 22-Fr sheath (white arrow) houses 12-Fr periscope sheath (blue arrow) into SMA as well as 8-Fr sheath (orange arrow) positioned to try to cannulate renal artery.

FIG 14 • Bottom of both periscope stents (SMA and right renal) are at blue arrow position and therefore lower than bottom of planned distal component of main body endograft (white arrow).

FIG 15 • A. Main body endograft deployed while periscope sheaths still in place. B. After withdrawal of sheaths, periscope stents (Viabahns) are deployed.

FIG 16 • Balloon molding of main body endograft with compliant aortic balloon against balloon-expandable bare stents placed within periscope stents at level of contact and distal seal. P.143

FIG 17 • A. Proximal angiography shows region of proximal aneurysm to treat. B. Proximal main body endograft is delivered and overlap is molded with compliant aortic balloon.

FIG 18 • Completion CTA showing exclusion of aneurysm and periscope stents in excellent position, perfusing SMA and right renal artery.

PEARLS AND PITFALLS Indications

▪ Follow general recommendations for elective repair of abdominal aortic aneurysms (AAAs) and consider raising criteria when applying complex snorkel/chimney/periscope procedures to these often compromised patients. ▪ Most of these procedures use approved devices in an off-label manner so informed consent to discuss all available options is important.

Preoperative workup

▪ High-quality imaging and the ability to manipulate images on a 3-D workstation are mandatory for successful preoperative planning and device choices. ▪ Adequate preoperative and perioperative hydration is important, given the amount of renal artery manipulation that occurs during these cases.

Patient setup

▪ The advanced imaging afforded by a dedicated hybrid endovascular suite allows improved visualization during these very technically demanding procedures.

▪ A well-trained staff and two-surgeon approach are important to ensure safe delivery of endograft components from both the femoral and brachial positions. Arm access

▪ Two 7-Fr sheaths can be placed in the high brachial position from a transverse incision, and the puncture sites need to be at least 2 to 3 cm away from each other to allow safe and independent arteriotomy closure.

Renal cannulations

▪ A coaxial system with sheath and covered stent into the target renal or visceral vessel from the brachial approach optimizes safe and accurate deployment of snorkel stents. ▪ Careful wire manipulation in distal renal and using less stiff wires with J-tips, if possible, minimizes likelihood of renal parenchymal injury and theoretical possibility of renal microemboli.

Balloon molding sequence

▪ Careful attention to sequence of snorkel/chimney/periscope balloon sequence minimizes gutter formation, promotes good neck apposition, and prevents compression of vital visceral and renal branches.

POSTOPERATIVE CARE At the conclusion of the procedure, patients are usually extubated, observed for 2 to 3 days in a monitored setting (in the intensive care unit overnight if lumbar drain present), and discharged home when ambulating, tolerating a normal diet, and with stable renal function. Clopidogrel and aspirin are given if the patients are not already taking these medications for at least 6 weeks postoperatively.

OUTCOMES Multiple reviews of the worldwide experience with snorkel/chimney and periscope techniques continue to find it to be technically successful with target revascularization rates in the 95% to 100%, mortality in the 2% to 5% range, morbidity up to 10%, and midterm renal and branch patency rates of 92% to 96%.12,13 Rupture-free survival after snorkel/chimney or periscope EVAR is excellent in the small amount of literature published P.144 on this new approach but will be important to observe in the mid- and long-term to ensure that this technique is durable as a strategy for endovascular repair of complex aneurysms.

COMPLICATIONS Perioperative complications related to complex EVAR in general include cardiac ischemia, arrhythmias or exacerbation of heart failure, groin wound seroma and infection, early thrombosis of endograft components, and bleeding issues related to access site. Reported rates of these issues are not particularly different than the wealth of literature for routine EVAR. Particular to snorkel/chimney techniques involve the use of the arm access, which has the potential of leading to arm ischemia, nerve injury/irritation of the brachial plexus, and axillary seromas.

Wire and catheter manipulation and poor wire hygiene can lead to inadvertent renal parenchymal injury that can lead to hematomas and excessive bleeding requiring transfusion. The rate of renal function decline is certainly more than in standard EVAR, although we do not believe it to be worse than open suprarenal surgery, fenestrated, or branched devices. Right arm access for multiple snorkel/chimney stents has been reported to lead to higher rates of cerebrovascular complications.1,8 This is likely due to moderate amounts of time that sheaths are across the aortic arch and the possibility of thrombus formation that can lead to cerebral emboli. Gutter leaks are a unique consequence of the parallel stent graft strategy and are poorly understood. Some general guidelines involve placing as long of stents as possible in parallel configuration to force gutter leaks to thrombose, and careful long-term imaging follow-up to ensure that the aneurysm is excluded.

REFERENCES 1. Lee JT, Greenberg JI, Dalman RL. Early experience with the snorkel technique for juxtarenal aneurysms. J Vasc Surg. 2012;55:935-946. 2. Knott AW, Klara M, Duncan AA, et al. Open repair of juxtarenal aortic aneurysms (JAA) remains a safe option in the era of fenestrated endografts. J Vasc Surg. 2008;47:695-701. 3. Greenberg RK, Sternbergh WC III, Makaroun M, et al. Intermediate results of a United States multicenter trial of fenestrated endograft repair for juxtarenal abdominal aortic aneurysms. J Vasc Surg. 2009;50:730737. 4. Greenberg RK, Clair D, Srivastava S, et al. Should patients with challenging anatomy be offered endovascular aneurysm repair? J Vasc Surg. 2003;38:990-996. 5. Ohrlander T, Sonesson B, Ivancev K, et al. The chimney graft: a technique for preserving or rescuing aortic branch vessels in stent-graft sealing zones. J Endovasc Ther. 2008;15:427-432. 6. Donas KP, Torsello G, Austermann M, et al. Use of abdominal chimney grafts is feasible and safe: shortterm results. J Endovasc Ther. 2010;17:589-593. 7. Bruen KJ, Feezor RJ, Daniels MJ, et al. Endovascular chimney technique versus open repair of juxtarenal and suprarenal aneurysms. J Vasc Surg. 2011;53:895-905. 8. Coscas R, Kobeiter H, Desgranges P, et al. Technical aspects, current indications, and results of chimney graft for juxtarenal aortic aneurysms. J Vasc Surg. 2011;53:1520-1527. 9. Moulakakis KG, Mylonas SN, Avgerinos E, et al. The chimney graft technique for preserving visceral vessels during endovascular treatment of aortic pathologies. J Vasc Surg. 2012;55:1497-1503. 10. Al-Khatib WK, Dua MM, Zayed MA, et al. Percutaneous EVAR in females leads to fewer wound complications. Ann Vasc Surg. 2012;26:476-482.

11. Rancic Z, Pfammatter T, Lachat M, et al. Periscope graft to extend distal landing zone in ruptured thoracoabdominal aneurysms with short distal necks. J Vasc Surg. 2010;51:1293-1296. 12. Katsargyris A, Oikonomou K, Klonaris C, et al. Comparison of outcomes with open, fenestrated, and chimney graft repair of juxtarenal aneurysms: are we ready for a paradigm shift? J Endovasc Ther. 2013;20:159-169. 13. Donas KP, Pecoraro F, Bisdas T, et al. CT angiography at 24 months demonstrates durability of EVAR with the use of chimney grafts for pararenal aortic pathologies. J Endovasc Ther. 2013;20:1-6.

Chapter 18 Branched and Fenestrated Endovascular Stent Graft Techniques Gustavo S. Oderich Karina S. Kanamori Anatomic constraints for endovascular management of abdominal aortic aneurysms include the presence of short or angulated surgical necks and aneurysmal degeneration of the origins of the visceral arteries. Fenestrated and branched endografts were introduced to enable minimally invasive repair of complex juxtaand suprarenal aortic aneurysms.1 These devices incorporate reinforced fenestrations or directional branches, permitting incorporation of visceral artery origins into the proximal endograft seal zone without compromising end-organ perfusion or aneurysm exclusion.2 This chapter summarizes the technical features of endovascular aneurysm repair using fenestrated and branched stent grafts for pararenal and thoracoabdominal aortic aneurysms.

DEFINITION The term fenestrated repair refers to deployment of an endograft featuring custom orifices created and reinforced at precise locations around the aortic perimeter to enable branch artery access, cannulation, and placement of a bridging stent graft in the course of aneurysm exclusion. Fenestration sites are created from patient-specific cross-sectional image data to enable exclusion of aneurysms with short or angled infrarenal necks. In most circumstances, the target arteries (e.g., renal or mesenteric) must arise from normal aorta to enable fenestrated repair. As a rule, fenestrations must be able to deploy flush with the aortic wall to ensure adequate aneurysm exclusion. “Alignment” stents (covered or uncovered, depending on individual patient circumstance) are deployed as needed to prevent target artery malperfusion as a consequence of misalignment between the fenestration and target artery orifice.

Branched repair refers to endovascular aneurysm exclusion employing covered stents to directly connect the main lumen of the endograft to the target visceral artery. These devices enable repair of aneurysms involving or extending proximal to the origins of the renal or visceral vessels (e.g., type IV thoracoabdominal aortic aneurysms [TAAAs]). Of necessity, some distance must be present between the main body of the endograft at full deployment and the aortic wall at the target visceral artery orifice. Branched stent grafts are currently available in two distinct configurations: Fenestrated branches arise from reinforced fenestrations bridged by balloon-expandable covered stents. Directional or cuffed branch devices feature appended fabric cuffs, precisely located to enable straight, helical, down- or up-going guidewire egress, target vessel cannulation, and deployment of bridging covered stents. Self-expanding flexible nitinol stents are usually employed for this purpose.

DIFFERENTIAL DIAGNOSIS Most aneurysms are degenerative (previously characterized as “atherosclerotic,” based on a similar, although not identical, causal risk factor profile). Other relevant etiologies include infection (e.g., mycotic aneurysms), inflammation (e.g., inflammatory

aneurysm or aortitis), development of penetrating ulcers or asymmetric saccular enlargement, and related aortic pathologies (dissection or intramural hematoma).

PATIENT HISTORY AND PHYSICAL FINDINGS Most patients’ aneurysms do not prompt symptoms prior to catastrophic rupture and are diagnosed incidentally or during screening. Indications for repair are size greater than 5.5 cm for males and greater than 5 cm for females or enlargement greater than 5 mm in 6 months.3 In approximately 5% to 10% of patients, aneurysms induce periaortic inflammation and resultant retroperitoneal fibrosis involving adjacent structures, including the duodenal and ureters.4 These patients may present with abdominal or back pain, fatigue, malaise, or low-grade fever even at relatively small diameters. Commonly, these aneurysms also enlarge at accelerated and unpredictable rates. Other uncommon presentations of abdominal aortic aneurysm disease include the presence of distal embolization with “blue toe syndrome,” congestive heart failure from aortocaval fistulae, or gastrointestinal bleeding from primary aortoenteric fistulae. A comprehensive history should be obtained to fully appreciate the potential natural history of each patient’s disease, including a comprehensive assessment of cardiovascular risk factors, current smoking habits, and a family history of aneurysmal disease or connective tissue disorders. Evaluation of perioperative clinical risk emphasizes cardiac, pulmonary, and renal functional status and reserve, including baseline laboratory testing, noninvasive cardiac stress testing, pulmonary function assessment, and carotid duplex ultrasonography when indicated.

DIAGNOSTIC IMAGING Preprocedural aortic imaging studies provide fundamental and necessary guidance for endovascular repair strategies of all types. Aneurysm morphology is best analyzed through acquisition of high-resolution computed tomography angiography (CTA) datasets.5 CTA with submillimeter slice acquisition is recommended for optimal acquisition, allowing three-dimensional reformatting techniques, maximum intensity projections, and volume rendering. P.146 Stent grafts are currently custom-made to conform to patient anatomy, based on estimates of longitudinal distance, axial clock position, arc lengths, and angles derived from centerline of flow measurements. Anatomic limitations to be considered include difficult iliac access, excessive aortic tortuosity, visceral artery occlusive disease, and anatomic variants including multiple accessory renal arteries or early renal branch bifurcation.

STENT GRAFT DESIGN Device planning starts with selection of the proximal landing zone based on “healthy” aorta. The proximal landing zone should include at least a 2-cm length of “normal,” noncalcified, parallel aortic wall. The outer-toouter aortic diameter should be more than 18 mm and less than 32 mm for pararenal aneurysms and more than 18 mm and less than 38 mm for TAAAs.6 Landing zone diameter should be no larger than the diameter of the next most proximal aortic segment. Fenestrated stent grafts are currently manufactured with three fenestration options: small and large circles and more proximal scallops (FIG 1A). Small fenestrations are 6 × 6 mm or 6 × 8 mm, created without crossing struts and reinforced by circumferential nitinol rings. Large fenestrations’ diameters are 8, 10, or 12 mm and may incorporate stent struts crossing the edge or middle of the circular defect, limiting space available for

alignment stents. Scallops are contoured indentations along the upper edge of the main body endograft fabric, 10 mm wide and ranging in height from 6 to 12 mm, depending on individual patient anatomy.5 Device designs vary with aneurysm extent. For pararenal aneurysms, 70% of patients are adequately treated with two small fenestrations for the renal arteries and a scallop for the superior mesenteric artery (SMA).5 Suprarenal and type IV TAAAs typically require four fenestrations (no scallops). Extensive TAAAs (types I to III) need directional branches, particularly if the aortic diameter is relatively large or aneurysmal at the level of the visceral arteries. The combination of directional branches for celiac and SMA management with fenestrations for the renal arteries is increasingly popular.

SURGICAL MANAGEMENT Ancillary Tools These procedures require advanced endovascular skills and a comprehensive inventory of applicable catheters, balloons, and stents (Table 1). Dedicated training in fenestrated and branched techniques is highly recommended for physicians already experienced in endovascular disease management and ancillary procedures including renal and visceral artery disease management.

Perioperative Measures Patients with difficult aneurysm anatomy, chronic kidney disease, or advanced age are preadmitted for bowel preparation and intravenous hydration with bicarbonate infusion. Oral acetylcysteine is administered to minimize risk of periprocedural renal dysfunction following administration of iodinated contrast. Hybrid, fixed imaging platforms are essential for optimal results of these complex procedures. Most are performed using general endotracheal anesthesia; local or regional anesthesia may be sufficient in select cases. Intraoperative blood salvage systems (“cell saver”) are recommended for difficult cases and all TAAAs. The creation of large, impermeable pockets within dependent portions of the surgical drapes will facilitate pooling and collection via the cell saver. P.147 The use of iodinated contrast is minimized by avoidance of power injector digital substraction angiography (DSA) runs during device implantation and side stent placement. Whenever possible, hand injections of dilute contrast (70% saline) are used to locate the side branches. Completion aortography is obtained only after all stents are positioned and postdilated, again using diluted contrast (50%). To minimize contrast, precatheterization of targeted visceral arteries or use of onlay computed tomography (CT) images, when available, is recommended. In experienced hands, precatheterization adds little to the overall procedure time.

FIG 1 • A. There are three types of fenestrations that can be manufactured: small, large, and scallop fenestrations. The fenestrated stent graft consists of a proximal fenestrated tubular component, a distal bifurcated universal component, and a contralateral iliac limb extension. B. The Cook Zenith® stent graft lineage. C. Newer design with two straight down-going branches and two fenestrations.

Positioning Patients are positioned supine with the imaging unit oriented from the head of the table. Both arms are tucked for repair of pararenal aneurysms requiring up to three fenestrations. Brachial artery access is used in patients treated by directional branches or those who need four fenestrations. The left arm is abducted and prepped in the surgical field up to the axilla. A working sterile side table is oriented in the same axis of the abducted arm for optimal support of necessary wires and catheters. Electrocardiogram (EKG) leads, urinary catheter, and other monitoring cables and lines should be taped or secured so that they are not in the path of the x-ray beam of the fluoroscopic unit and do not impede movement of the C-arm gantry.

Arterial Access Access is established in the femoral arteries. Patients with small, calcified, or stenotic iliac arteries may require creation of an iliac conduit for safe device delivery. Total percutaneous femoral access is the preferred approach in patients with noncalcified arteries or mild posterior plaque. The standard “preclose” technique enables complete hemostasis in more than 95% of patients irrespective of sheath diameter.7 When femoral arteries are small, calcified, P.148 or bifurcate close to the inguinal ligament, standard surgical exposure and access is obtained. Proximal and

distal control is obtained using vessel loops. The left brachial artery is surgically exposed via small longitudinal incision in the upper arm, just proximal to the origin of the deep brachial artery. Intravenous heparin (80 to 100 units/kg) is administered immediately after femoral and brachial access is established. An activated clotting time longer than 250 seconds is maintained throughout the procedure with frequent rechecks every 30 minutes. Prior to deployment of the stent graft, diuresis is induced with intravenous mannitol and/or furosemide.

Table 1: List of Ancillary Tools Recommended for Physicians Performing Fenestrated Stent Graft Procedures Category

Manufacturer

Application

20- to 24-Fr Check-Flo sheath (30 cm)

Cook Medical, Bloomington, IN

Femoral access for multivessel catheterization

7-Fr Ansel sheath (55 cm, flexible dilator)

Cook Medical, Bloomington, IN

Femoral access for branch artery stenting

7- or 8-Fr Raabe sheath (90 cm long)

Cook Medical, Bloomington, IN

Brachial access for branch artery stenting

12-Fr Ansel sheath (55 cm, flexible dilator)

Cook Medical, Bloomington, IN

Brachial access for tortuous aortic arch to facilitate branch artery stenting

5-Fr Shuttle sheath (90 cm)

Cook Medical, Bloomington, IN

Branch artery access during difficult arch

Kumpe catheter 5 Fr (65 cm)

Multiple

Selective vessel catheterization

Kumpe catheter 5 Fr (100 cm)

Multiple

Selective vessel catheterization

Cl catheter 5 Fr (100 cm)

Multiple

Selective vessel catheterization

MPA catheter 5 Fr (125 cm)

Multiple

Selective vessel catheterization

MPB catheter 5 Fr (100 cm)

Multiple

Selective vessel catheterization

Van Schie 3 catheter 5 Fr

Cook Medical,

Selective vessel catheterization

Sheaths

Catheters

(65 cm)

Bloomington, IN

Vertebral catheter 4 Fr (125 cm)

Multiple

Selective vessel catheterization

VS1 catheter 5 Fr (80 cm)

Multiple

Selective vessel catheterization

Simmons I catheter 5 Fr (100 cm)

Multiple

Selective vessel catheterization

Diagnostic flush catheter 5 Fr (100 cm)

Multiple

Diagnostic angiography

Diagnostic pigtail catheter 5 Fr (100 cm)

Multiple

Diagnostic angiography, selective vessel catheterization

Quick-cross catheter 0.014 in to 0.035 in (150 cm)

Spectra-Medics

Selective vessel catheterization

Renegade catheter (150 cm)

Boston Scientific, Minneapolis, MN

Selective vessel catheterization

LIMA guide 7 Fr (55 cm)

Cordis Corporation, Bridgewater, NJ

Precatheterization

Internal mammary (IM) guide 7 Fr (100 cm)

Multiple

Selective vessel catheterization

MPA guide 7 Fr (100 cm)

Multiple

Selective vessel catheterization

10-mm × 2-cm angioplasty balloon

Multiple

Proximal stent flare

12-mm × 2-cm angioplasty balloon

Multiple

Proximal stent flare

5-mm × 2-cm angioplasty balloon

Multiple

Advance sheath over balloon

Multiple

Initial access

Guide catheters

Balloons

Wires Bentson wire 0.035 in (150

cm) Soft glidewire 0.035 in (260 cm)

Multiple

Target vessel catheterization

Stiff glidewire 0.035 in (260 cm)

Multiple

Target vessel catheterization

Rosen wire 0.035 in (260 cm)

Multiple

Branch artery stenting

1-cm tip Amplatzer wire 0.035 in (260 cm)

Multiple

Branch artery stenting

Lunderquist wire 0.035 in (260 cm)

Multiple

Aortic stent graft

Glidegold wire 0.018 in (180 cm)

Multiple

Target vessel catherization

iCAST stent grafts 5 to 10 mm

Atrium, Hudson, NH

Branch artery stenting

Balloon-expandable stents 0.035 in

Multiple

Branch artery stenting or reinforcement

Self-expandable stents 0.035 in

Multiple

Distal branch artery stenting

Self-expandable stents 0.014 in

Multiple

Distal branch artery stenting

Stents

MPA, main pulmonary catheter; VS1, Van Schie 1; LIMA, left internal mammary artery.

ENDOVASCULAR REPAIR USING FENESTRATED STENT GRAFTS Fenestrated-branched repair is currently performed using the Cook Zenith® stent graft lineage. Newer designs by Endologix (Ventana), Terumo (Anaconda), and Cook Medical (p-Branch) are under clinical investigation. The Cook Zenith® fenestrated stent graft consists of a proximal fenestrated tubular component, a distal bifurcated universal component, and a contralateral iliac limb extension (FIG 1A). The fenestrated tubular component is custommade to fit the patient’s anatomy. Four to 6 weeks are required for manufacturing and delivery in the United States. Bilateral percutaneous femoral access is established under ultrasound guidance; each femoral puncture

is preclosed using two Perclose devices. Bilateral 8-Fr sheaths are introduced to the external iliac arteries over Benson guidewires (Cook Medical, Bloomington, IN). The guidewires are exchanged to 0.035-in soft glidewires and Kumpe catheters, which are advanced to the ascending aorta and exchanged for stiff 0.035-in Lunderquist guidewires (Cook Medical, Bloomington, IN). Choice of access site is dependent on tortuosity and vessel diameter. Provided there are no issues with both iliac arteries, the branches are performed via the right femoral approach, whereas the fenestrated and bifurcated devices are introduced via the left femoral approach. A 20-Fr (two fenestrations) or 22-Fr (three fenestrations) Check-Flo sheath (Cook Medical, Bloomington, IN) is introduced via the right femoral approach (FIG 2A). The valve of the P.149 Check-Flo sheath has four leaflets, which are accessed by two short 7-Fr sheaths at 2 o’clock and 7 o’clock positions. Precatheterization of the renal arteries is performed using 0.035-in soft glidewires and 5-Fr Kumpe or C1 catheters (Cook Medical, Bloomington, IN), which are supported by 7-Fr left internal mammary artery (LIMA) guide catheters (FIG 2B). Alternatively, onlay fusion CTA is recommended to minimize contrast use. Once the target vessels are catheterized, the fenestrated stent graft is oriented extracorporeally, introduced via the left femoral approach, and deployed with optimal apposition between the fenestrations and the target catheters. Proper device orientation, using the anterior and posterior markers, is essential. It is useful to deploy the first two or three stents and then rotate the imaging unit laterally, confirming alignment between the catheter and its respective fenestration. The device should be deployed slightly higher than what is anticipated, with the catheter matching the lowest of the four radiopaque markers in the fenestration. The diameter-reducing wire on the fenestrated component allows for some rotational and cranial-caudal movement to optimize alignment following initial deployment. After deployment of the fenestrated component, each catheter is removed from its target artery and used to sequentially regain target vessel access through the respective fenestration. (FIG 2C). In most cases, when alignment is carefully confirmed prior to attempted cannulation, the target vessel is accessed without difficulty. After the target vessel is catheterized, soft glidewire is removed and hand injection is used to confirm location. The glidewire is exchanged for a 0.035-in Rosen guidewire (Cook Medical, Bloomington, IN). The Rosen guidewire has a floppy J tip, reducing the risk of branch renal artery perforations. When additional support is required, the Amplatz guidewire (Cook Medical, Bloomington, IN) with 1-cm soft tip can be used. After the Rosen or stiff guidewire of choice is positioned, a 7-Fr Ansel sheath with flexible dilator is advanced. If there is difficulty to advance the sheath, an undersized balloon may be used as a dilator to facilitate advancement. Once the sheath is in position, an alignment stent is positioned under protection of the sheath with the tip of the stent just beyond the tip of the sheath (FIG 2D). For repairs requiring two or three vessel fenestrations, the target vessels are accessed sequentially using femoral approach. For those requiring four fenestrations, the celiac axis is accessed via brachial approach using a preloaded catheter, which is placed through the celiac fenestration and exits the stent graft via an access scallop at the top of the device. The diameter-reducing tie on the fenestrated segment is removed after all the target arteries are accessed and secured by 7-Fr hydrophilic sheaths.

The top cap of the device is advanced forward to deploy the uncovered fixation stent (FIG 3A). The top cap is retrieved prior to deployment of the alignment stents. After the top cap and dilator are removed, the proximal landing zone is gently dilated using a compliable balloon such as the Coda balloon (Cook Medical, Bloomington IN, FIG 3B). It is critical that the balloon dilatation is performed prior to placement of alignment stents, or alternatively, each stent has to be protected by separate balloons. The alignment stents are sequentially deployed following removal of the diameter-reducing tie, retrieval of the top cap, and balloon dilatation of the neck. The sequence of stent deployment is renal arteries followed by SMA and celiac axis. Prior to each stent deployment, the position of the stent is confirmed by hand injection. The stent is deployed 3 to 5 mm into the aorta (FIG 3C) and flared P.150 using a 10-mm × 2-cm balloon (FIG 3D). A completion angiography of each branch is performed using hand injection after direct injection of 100 to 200 μg of nitroglycerin to minimize spasm. Following placement of the alignment stents, a distal bifurcated stent graft is oriented, advanced, and deployed with preservation of the ipsilateral internal iliac artery. The dilator of the bifurcated device may encroach the contralateral renal stent or the SMA stent. In these cases, it is useful to leave a 10-mm balloon ready to be inflated in the renal stent to prevent damage (FIG 4A, inset). The minimum overlap between the bifurcated and the fenestrated component is two full-length stents (17 mm each), but ideally, more than three full stents is recommended to minimize risk of component separation (FIG 4B).8 After deployment of the bifurcated device, the dilator is removed with care to avoid damage or dislodgement of the renal stents. The contralateral gate is catheterized using a soft glidewire and 5-Fr catheter (FIG 4B). Access is confirmed by 360-degree catheter rotation. The glidewire is exchanged for a 0.035-in Lunderquist guidewire. Limited iliac angiography using contralateral oblique views with hand injection. The contralateral limb extension is deployed with preservation of the internal iliac artery (FIG 4C). A completion angiography of the aorta and iliac arteries is obtained using power injection to demonstrate patency of the visceral arteries, main body, iliac limbs, and iliac arteries.

FIG 2 • A. A 20-Fr (two fenestrations) or 22-Fr (three fenestrations) Check-Flo sheath (Cook Medical, Bloomington, IN) is introduced via the right femoral approach. B. Precatheterization of the renal arteries. C. Sequentially regain access into the fenestrated component, fenestration, and target vessel. D. An alignment stent is advanced under protection of the sheath.

FIG 3 • A. The top cap of the device is advancing forward allowing deployment of the uncovered fixation stent. B. The proximal landing zone is gently dilated using a compliable balloon. Stent deployed 3 to 5 mm into the aorta (C) and flared using a 10-mm × 2-cm balloon (D).

FIG 4 • To avoid the dilator of the bifurcated device encroaching the contralateral renal stent or the SMA stent, leave a 10-mm balloon ready to be inflated in the renal stent (A, inset). B. The minimum overlap between the bifurcated and the fenestrated component is more than two full-length stents. C. The contralateral limb extension is deployed with preservation of the internal iliac artery.

ENDOVASCULAR REPAIR USING MULTIPLE DIRECTIONAL BRANCHES (MULTIBRANCH TBRANCH STENT GRAFT) Directional branches created with presewn cuffs are currently available from Cook Zenith® stent graft lineage on an investigational-use basis (FIG 1B). A four-vessel multibranch stent graft design (T branch) is also being investigated for treatment of TAAAs.9 The extent of repair varies depending on the proximal extension of aneurysm within the thoracic aorta. The procedure is performed using bilateral femoral and left brachial approach. In general, the repair starts with deployment of a proximal thoracic TX2 stent graft (Cook Medical, Bloomington, IN) followed by deployment of the T-branch stent graft (Cook Medical, Brisbane, Australia) and distal bifurcated component and contralateral limb extension. The self-expandable stents are placed into the four branches following deployment of all aortic components. The critical steps are reviewed as follows: Bilateral femoral and left brachial arterial access is obtained (FIG 5A). A proximal thoracic stent graft is deployed if needed depending on aneurysm extent. P.151 Precatheterization of the renal arteries is not required, but it is critical that the distal edge of the directional branch is deployed above its intended target vessel. To guide deployment of the T-branch component, the SMA is precatheterized via the brachial approach (FIG 5B). The T-branch stent graft is oriented extracorporeally, introduced via the femoral approach, and deployed with the directional branches located proximal to its intended target vessel (FIG 5C). Deployment of the distal universal bifurcated stent graft and contralateral iliac extension are identical P.152 to what was described in the fenestrated technique (FIG 5D). The femoral arteries are closed at this point, restoring flow into the lower extremities. It is useful to maintain access into one of the femoral arteries with a 5-Fr sheath (FIG 5E, inset). This maneuver allows passage of a 0.014-in guidewire from the left brachial artery to femoral artery. The guidewire is clamped in both ends, which locks the 12-Fr sheath in place and provides support for deployment of the side branches. The 12-Fr Ansel I sheath (Cook Medical, Bloomington, IN) is advanced via the left brachial approach and positioned inside the T-branch component in the descending thoracic aorta (FIG 5E). At this point, a 0.014-in guidewire is advanced through and through from the left brachial to femoral artery, preventing movement of the 12-Fr sheath in the aortic arch. Each side branch is individually catheterized in a sequential fashion, starting with the renal arteries (FIG 5F) followed by the SMA and celiac axis. A 5-Fr main pulmonary artery (MPA) or Kumpe catheter (Cook Medical, Bloomington, IN) is used to access the directional branch and target vessel. Once the vessel is catheterized, the soft glidewire is exchanged for a stiff guidewire (Rosen or short-tip Amplatzer, Cook Medical, Bloomington, IN), which is positioned in the target vessel. A 9-Fr 80-cm flexor sheath (Cook Medical, Bloomington, IN) is advanced coaxially within the 12-Fr sheath into the target vessel. Each target vessel is stented with a self-expandable stent graft (FIG 5F). The stent graft should be oversized by 1 to 2 mm and should provide at least 2 cm of distal landing zone in the target vessel, extending 3 to 5 mm into the aortic lumen of the T-branch device. To prevent kinks in the transition of the stent graft to the target artery, each self-expandable stent graft

is reinforced by a second self-expandable uncovered stent, which is deployed 1 cm beyond the distal edge of the stent graft (FIG 5G). Selective completion angiography is obtained for each sequential branch. A completion angiography of the arch and thoracoabdominal aorta is obtained after all matting stent grafts are deployed (FIG 5H).

FIG 5 • A. Endovascular repair using multiple directional branches is performed using bilateral femoral and left brachial approach. Deployment of proximal thoracic TX2 stent graft (Cook Medical, Bloomington, IN) (B), followed by deployment of the T-branch stent graft (Cook Medical, Brisbane, Australia) (C), and distal bifurcated component and contralateral limb extension (D). The femoral arteries may be closed, restoring flow into the lower extremities; maintain access into one of the femoral arteries using a 5-Fr sheath (E, inset). F,G. 9-Fr 80-cm flexor sheath (Cook Medical, Bloomington, IN) is advanced into the target vessel, followed by placement of a self-expandable stent graft. H. Complete procedure.

ENDOVASCULAR REPAIR USING TWO DIRECTIONAL BRANCHES AND TWO FENESTRATIONS (TWO BRANCH-TWO FENESTRATED STENT GRAFT) A design with directional branches for the celiac and SMA and fenestrations for the renal arteries has been widely used at the Cleveland Clinic.10 More recently, a newer design with two straight down-going branches and two fenestrations has been used ( FIG 1C). The advantage of the latter is the ability to provide short, transversely oriented branches for the renal arteries. The same principles already described for fenestrated stent grafts are applied with respect to device design, planning, and arterial access. Bilateral femoral access and left brachial artery access is needed (FIG 6A). The right femoral access is used for precatheterization of the renal arteries. The left brachial access is used for the celiac axis and SMA (FIG 6B). A proximal thoracic TX2 stent graft (Cook Medical, Bloomington, IN) is deployed first, depending on proximal extension of the aneurysm (FIG 6A). After the renal arteries and SMA are precatheterized, the fenestrated-branched stent graft is oriented extracorporeally, introduced via the femoral approach and deployed with perfect apposition between the renal fenestrations and the target renal arteries (FIG 6B). The celiac and SMA branch are accessed using preloaded catheters and glidewires, which are snared via the left brachial approach (FIG 6B). Each catheter is sequentially removed from the renal arteries and used to regain access into the fenestrated component, renal fenestration, and target renal artery (FIG 6C). Hydrophilic sheaths and alignment renal stents are advanced as previously described. The preloaded catheters in the SMA and celiac branch allow advancement of a 0.035-in soft glidewire, which is snared via the left brachial approach (FIG 6B). A sheath and catheter are advanced into the celiac branch. Following access into the celiac axis, a 0.035-in Amplatz guidewire is placed. The SMA is accessed using similar steps, and after access is established with Amplatz guidewire, a 9-Fr sheath is advanced to allow positioning of a self-expandable stent graft. Once all four vessels are catheterized and sheaths are positioned into the renal arteries and SMA, the diameterreducing tie is removed, allowing complete expansion of the fenestrated-branched component (FIG 6D). Sequential target artery stenting is performed using balloonexpandable covered stents for the renal fenestrated branches (FIG 6E, inset) and self-expandable stent grafts for the SMA and celiac axis (FIG 6E, inset). Selective branch angiography is performed after each branch stent is placed. Deployment of distal bifurcated component and contralateral iliac limb extension is identical to what has been described for fenestrated stent grafts (FIG 6F). P.153

FIG 6 • A. Bilateral femoral access and left brachial artery access is needed. B. After the renal arteries and SMA are precatheterized, the fenestrated-branched stent graft is oriented extracorporeally, introduced via the femoral approach. The celiac and SMA branch are accessed using preloaded catheters and glidewires, which are snared via the left brachial approach. C. Regain access into the fenestrated component, renal fenestration, and target renal artery. D. Complete expansion of the fenestrated-branched component. Sequential target artery stenting is performed using balloon-expandable covered stents for the renal fenestrated branches and self-expandable stent grafts for the SMA and celiac axis (E, inset). F. Deployment of distal bifurcated component and contralateral iliac limb extension.

P.154

PEARLS AND PITFALLS Preoperative

▪ Complete history and physical examination with emphasis on cardiovascular risk

evaluation

factors, family history of aneurysm disease, and connective tissue disorders ▪ Preoperative medical evaluation focused on cardiac, pulmonary, and renal performance ▪ Aortic imaging with computed tomography angiography allows detailed analysis of aneurysm morphology for stent graft design and procedure planning.

Arterial access

▪ Iliac conduits are recommended in patients with small, diseased, or excessively tortuous iliac arteries. ▪ Pelvic perfusion with maintenance of internal iliac artery flow decreases risk of spinal cord injury.

Stent graft implantation

▪ Precise stent graft design and implantation are critical aspects of the procedure. ▪ Minimize use of iodinated contrast by avoiding contrast aortography during device implantation. ▪ Precatheterization and/or onlay CT allows precise device implantation with minimal need of angiography. ▪ Fenestrations are typically accessed via the femoral approach and stented using balloon-expandable covered stents. ▪ Directional branches are accessed via the brachial approach and stented using self-expandable stent grafts.

Misaligned fenestrations

▪ Excessive tortuosity in the iliac or visceral segment may cause misalignment of fenestrations and difficult target vessel catheterization. ▪ Rotation of the device, which is constrained by a diameter-reducing tie, and use of balloon displacement or curved catheters allow successful catheterization in most cases.

Branch perforation or dissection

▪ Small, diseased, and tortuous visceral arteries are prone to perforation or dissection, particularly if an Amplatz guidewire is needed to provide more support. ▪ Careful attention to detail and minimizing guidewire manipulation with close attention to the tip of the guidewire help prevent this complication.

Stent kinks

▪ Branch tortuosity may lead to kinks within the side stents. ▪ This should be immediately recognized and treated by placement of a second self-expandable stent to prevent branch occlusion.

POSTOPERATIVE CARE Length of stay averages 2 to 3 days for endovascular repair of pararenal aneurysms and 4 to 5 days for TAAAs. Cerebrospinal fluid drainage is discontinued on postoperative day 2, after a 6-hour clamp trial and documentation of normal coagulation profile. Oral diet is resumed the day after the operation for uncomplicated cases requiring two to three fenestrations, but it is typically withheld for 1 or 2 days for difficult cases or those requiring four fenestrations or branches. A CTA and baseline duplex ultrasound of the visceral branches is obtained prior to dismissal. Follow-up

includes clinical examination and imaging (CTA and ultrasound) in 6 to 8 weeks, every 6 months during the first year, and yearly 1 year, and early thereafter. Patients are started on aspirin indefinitely. Clopidogrel is not recommended unless there is a specific concern with one of the side branches because of small size (3%) are infrequent with proper selection of a healthy landing zone and adequate planning.23 In the U.S. fenestrated trial, there were no type I or III endoleaks.5 In the event of a type Ia endoleak, the proximal neck may be redilated, but all the alignment stents need to be protected by separate balloons. Type III endoleaks may result from inadequate flare, lack of apposition, use of bare metal stent, or inadequate length into the aorta. Stent kinks or narrowing Kinks are highly preventable and can be anticipated from careful review of vessel anatomy by CTA. These remain a cause of reintervention or branch vessel loss if not recognized. Short stents (60%) are determined by duplex-derived assessment of peak systolic velocity measurements across lesions. Baseline characteristics (i.e., kidney size, velocity, spectral waveforms, resistive indices) serve as reference points for future surveillance imaging following revascularization. Selective visceral and renal arteriograms are obtained to define normal and variant vascular anatomy, including lateral imaging of both the celiac and superior mesenteric arteries (FIGS 1 and 2). Computed tomography (CT) arteriography of the abdomen and pelvis, with arterial and venous pelvis, may provide additional useful information regarding the extent of aortic disease and other associated abdominal pathology (FIGS 3 and 4). Catheter-based arteriography alone may not identify significant arterial wall disease or the presence of aneurysmal lesions. However, the expense, contrast load, and radiation associated with complementary arteriographic imaging modalities may not be justified or appropriate in every patient, so anatomic information obtained from these examinations should be integrated into the operative plan on an iterative basis. Preoperative, imaging-based planning is combined with direct intraoperative assessment to create the most effective and durable revascularization possible for each patient. Documentation of celiac, hepatic, splenic, and superior mesenteric artery patency is a mandatory prerequisite for these procedures. Significant stenosis of the celiac origin or hepatic or splenic artery occlusive disease will prevent successful renal revascularization from these arteries. Associated superior mesenteric artery disease also needs to be considered, particularly when the gastroduodenal artery provides significant collateral flow from the celiac plexus to the mesenteric bed. Renal artery anatomy, including branch vessel involvement and the presence of multiple renal arteries also needs to be documented. Bilateral lower extremity vein mapping is also necessary to identify potential graft conduit. Standard vein mapping techniques, including imaging in a warm room with the patient in reverse Trendelenburg position, should be employed to ensure accuracy and reproducibility. For selected patients, a more extensive preoperative evaluation for coronary artery or valvular disease should be considered. This may include both a transthoracic echocardiogram and cardiac stress evaluation. Selective pulmonary evaluation may be required in patients with chronic obstructive pulmonary disease (COPD)associated respiratory P.185 compromise. Additional vascular assessments should be performed as indicated, including carotid duplex ultrasonography to assess the significance of carotid bruits identified on physical examination.

FIG 1 • Abdominal angiogram with lateral view shows a normal celiac artery.

FIG 2 • Abdominal angiogram with lateral view shows a stenotic celiac artery.

FIG 3 • Axial CT scan image shows a normal celiac artery origin.

FIG 4 • Axial CT scan image shows a diseased celiac artery origin.

SURGICAL MANAGEMENT Preoperative Planning The indications for hepatic and splenic artery-based renal revascularization are similar to those for aorta-renal revascularization and are discussed elsewhere.1,4 Although aorta-renal bypass is most direct and generally most expeditious, extraanatomic renal revascularization may be preferable in selected circumstances as previously noted. Review of preoperative imaging is performed to determine variant vascular anatomy, if present. Anatomy of the existing renal artery disease is assessed. The hepatic-right renal bypass requires a conduit, preferably autogenous vein. The spleno-left renal bypass may be performed with or without graft conduit. The native splenic artery is sufficient length, usually to extend directly to the left renal artery, when fully mobilized. When necessary due to variant anatomy, or prior inflammation or scarring around the pancreas, venous conduit can also be employed. Planning for availability of duplex ultrasonography in the operating room (OR) will facilitate intraoperative confirmation of adequate target revascularization and renal perfusion.

Positioning Patient is placed in supine position with both arms tucked.

A small bump is placed under the respective flank. The operative field is prepped from the nipples to the knees.

HEPATORENAL BYPASS Placement of Incision Optimal access is gained through a right subcostal incision extending from the midline to the tip of the 12th rib. In large or obese patients, the medial extent of the incision can be extended across the midline as a chevron (FIG 5). When necessary, an upper midline incision may also provide sufficient exposure.

Hepatic Artery Exposure The hepatoduodenal ligament is exposed by retracting the right lobe of the liver cephalad. The right colon and duodenum are reflected anteriorly and to the left (Kocher maneuver). The small intestine is packed toward the pelvis with moist laparotomy pads. The hepatoduodenal ligament is incised longitudinally. The hepatic artery is located in the porta hepatis medial to the common bile duct (FIG 6). The gastroduodenal artery is identified as the first large branch coursing caudad and encircled with a silastic loop. The gastroduodenal artery should be preserved in the presence of superior mesenteric artery occlusive disease as it provides important collateral circulation to the small intestines. The hepatic artery is controlled proximally and distally with silastic loops (FIG 7).

FIG 5 • Right subcostal incision extended to the tip of 12th rib.

Right Renal Artery Exposure The right colon and duodenum are reflected as detailed earlier to expose the inferior vena cava and right renal vein. The right renal artery is located posterior and superior to the main renal vein. Depending on its position, the renal vein is retracted either cephalad or caudad. To ensure the main renal artery is exposed, the dissection should be carried to its aortic origin. This requires medial retraction of the inferior vena cava and division of lumbar veins when necessary. The right renal artery is controlled using a silastic loop. The main renal artery is exposed circumferentially and then distally to the three segmental renal artery branches. Each branch is identified and controlled with a silastic loop. This is a critical operative maneuver that excludes the presence of branch disease and ensures a successful renal artery revascularization (FIG 7).

Distal Anastomosis The distal anastomosis is performed first to take advantage of the additional degrees of freedom provided by the mobile graft. An appropriate length of greater saphenous vein is harvested from the thigh. The patient is heparinized 100 units/kg. The vein itself is reversed before placement. P.186 The proximal renal artery is mobilized following its division from the aorta, at its origin. The proximal stump is oversewn with 5-0 polypropylene suture. Redundant renal artery is trimmed distally from its origin until the disease-free segment is reached. The mobile renal artery is then transposed anterior to the inferior vena cava. The vein graft and renal artery are spatulated and the end-to-end anastomosis created with continuous 6-0 polypropylene suture, knotted at opposite ends of P.187 the anastomosis to prevent purse-stringing. Alternatively, depending on renal artery diameter, eight interrupted sutures may be distributed circumferentially around the lumen. The smaller the renal artery diameter, the more advantageous the interrupted technique. Loupe magnification is necessary to ensure optimal results regardless of which suture technique is chosen (FIG 7). Once the distal anastomosis is completed, the vein graft is oriented longitudinally to prevent twisting or kinking prior to completion of the proximal anastomosis.

FIG 6 • A,B. Kocher maneuver with porta hepatis dissected. IVC, inferior vena cava.

FIG 7 • A,B. Right renal artery and distal branches encircled with silastic loops. Distal anastomosis is performed first. IVC, inferior vena cava. (continued)

FIG 7 • (continued)

FIG 8 • A. The proximal anastomosis between the hepatic artery and vein graft. B. Anterior-posterior angiographic image demonstrates a hepato-renal artery bypass.

Proximal Anastomosis Hepatic artery Small vascular clamps or removable clips are used to control the proximal and distal hepatic artery. An arteriotomy is made on the hepatic artery and extended using Potts scissors. The vein is spatulated and an end-to-side anastomosis is again performed with running polypropylene suture (FIG 8A). Gastroduodenal artery The gastroduodenal artery may be used as an alternative inflow vessel if sufficiently large (4 to 6 mm in diameter). This anastomosis may be performed either end-to-end or end-to-side, but prior to division of the gastroduodenal artery, consideration should be given toward its contribution to the mesenteric circulation (FIG 8B).

Intraoperative Duplex Ultrasonography We recommend insonation of the graft and both anastomoses using appropriately sized 7-MHz scan heads to ensure technical proficiency following completion of the bypass. In recent years, our practice has come to rely on P.188 duplex ultrasonography for intraoperative assessment of all small and medium size autogenous reconstructions, especially in light of the reduced frequency of such procedures in the era of endovascular and hybrid reconstructions. Renal artery reconstruction is unforgiving in that failure in the perioperative period cannot be expeditiously addressed after the abdomen is closed, almost always precipitating kidney infarction and permanent reductions in creatinine clearance.

Spectral waveforms, velocities, and B-mode are all employed to detect technical errors requiring immediate repair.

SPLENIC-RENAL BYPASS Placement of Incision Exposure is obtained through a left subcostal incision extending from the midline to the tip of the 12th rib. In large or obese patients, the medial extent of the incision can be extended across the midline as a chevron (FIG 9). As was the case on the right side, the upper midline incision may also provide sufficient access depending on body habitus, prior surgeries, and operator experience.

Splenic Artery Exposure The greater omentum is elevated exposing the transverse mesocolon. The ligament of Treitz is taken down and the inferior mesenteric vein is ligated and divided. The plane between the pancreas and kidney is entered and the pancreas elevated. The splenic vein is embedded in the body of the pancreas—avoid injury during mobilization of the distal pancreas. The splenic artery should be palpable along the cephalad border of the pancreas. It is mobilized free of surrounding parenchyma moving medially and laterally until sufficient length is obtained to fashion either a primary bypass or support an autogenous vein conduit (FIG 10).

FIG 9 • Left subcostal incision extended to the tip of 12th rib.

FIG 10 • Left renal artery and vein exposure. Division of the inferior mesenteric vein allows cephalad retraction of the retropancreatic plane, which allows visualization of the splenic artery. P.189

FIG 11 • A,B. The splenic artery and left renal artery are divided. The gonadal, adrenal, and lumbar veins are ligated and divided, allowing complete mobilization of the left renal vein.

Left Renal Artery Exposure After mobilizing the distal pancreas, the left renal vein is located just inferior and slightly caudad. The left renal vein is circumferentially mobilized. This requires division of its nonrenal tributaries: the gonadal, adrenal, and lumbar veins. Dividing these veins greatly enhances renal vein mobility, facilitating renal artery exposure from its position just cephalad and posterior to the vein. As previously described on the right, the left renal artery is dissected to its aortic origin and controlled with a silastic loop. The distal artery and its three segmental branches are identified and encircled with silastic loops. The importance of mobilization is again emphasized (FIG 11).

Splenic-Renal Anastomosis The patient is heparinized with 100 units/kg of unfractionated heparin. The left renal artery is clamped at the origin and divided. The renal stump is oversewn with a 5-0 polypropylene suture. The distal main renal artery is spatulated distal to the existing renal artery disease. The mobilized splenic artery is divided with sufficient length to extend behind the pancreas to the left renal artery without undue tension. The distal splenic artery is oversewn. The mobilized splenic artery is spatulated and anastomosed end-to-end to the left renal artery, again with either running or interrupted polypropylene suture depending on the respective arterial diameters (FIG 12). Alternatively, when splenic artery length is insufficient, reversed saphenous vein may be employed as a bridge graft. Again, to optimize the degrees of freedom, the distal anastomosis is performed first, followed by end-toend or end-to-side anastomosis to the splenic artery. The vein graft is positioned posterior and inferior to the body of the pancreas.

Intraoperative Duplex Ultrasonography As described earlier

FIG 12 • Completed anastomosis between the splenic artery and left renal artery.

P.190

FINAL INSPECTION With completion of the revascularization procedures, all anastomoses and oversewn renal artery origins are inspected for hemostasis. Heparin anticoagulation is reversed with protamine, in a quantity sufficient to normalize the activated clotting time (ACT). Palpation of the SMA at the base of the mesentery is performed to confirm a pulse. Operative traction and/or preexisting disease may compromise SMA flow or precipitate an occult dissection. If the SMA pulse is absent, or the intestinal viability uncertain, mesenteric artery revascularization may be necessary.

PEARLS AND PITFALLS Preoperative

▪ Surgical planning may require CT and catheter-based arteriography as

imaging

complementary references for surgical planning. ▪ Celiac artery stenosis is an absolute contraindication for hepatic- and splenicbased renal revascularization.

Preoperative vein mapping

▪ Autogenous vein is the preferred conduit for renal revascularization. ▪ Lower extremity vein mapping allows assessment for suitable conduit.

Exposure of the renal artery

▪ Circumferential exposure of the entire main renal artery and the three segmental branches is imperative for placement of the renal anastomosis distal to existing disease

Graft orientation

▪ Longitudinal orientation needs to be confirmed repeatedly during graft tunneling and orientation. Excessive reliance on graft marking or “striping” as the sole method of orientation may lead to inadvertent kinking or twisting.

Intraoperative duplex

▪ Completion duplex scanning is easy, quick, and invaluable in identifying technical errors, which may compromise graft patency and renal viability. ▪ Unlike lower extremity bypass procedures, perioperative graft occlusion cannot typically be identified expeditiously to prevent end-organ compromise.

POSTOPERATIVE CARE Postoperative care typically involves central venous and arterial pressure monitoring in an intensive care unit (ICU) environment, at least for the first 24 to 48 hours. Serial monitoring of serum creatinine, urine output, and acid-base status is essential in the early postoperative period. Unexplained changes in acid-base or elevation of serum creatinine could indicate occlusion of the revascularization itself or progressive mesenteric ischemic. Blood pressure is maintained in a physiologic range with vasoactive medications as necessary. Oral antihypertensives are resumed on postoperative day 1 and adjusted depending on the response to renal revascularization. Diet is resumed as bowel function returns; nasogastric suction is usually not required. Blood pressure and antihypertensive medication requirements may decrease after renal revascularization and should be adjusted prior to discharge. Follow-up surveillance duplex ultrasonography is performed at 6 and 12 months then annually thereafter. Detected abnormalities suggesting stenosis of the renal reconstruction may be addressed with remedial endovascular intervention or surgical revision when indicated.

OUTCOMES Large case series documenting the outcomes following isolated hepatorenal and splenorenal artery bypass are sparse. Published results are derived from two relatively large series, generally demonstrating acceptable perioperative morbidity and mortality with improved renal function and blood pressure and durable patency.

Moncure et al. reported 77 patients who underwent 79 procedures (29 hepatorenal, 50 splenorenal bypass) for the treatment of renovascular hypertension and renal preservation. The perioperative mortality was 6%. Deterioration in renal function occurred on three occasions but only in patients with bilateral simultaneous repair. Cure or improvement in hypertension was observed in 52 of 63 patients. Renal function was preserved or improved in 67 of 77 patients.2 Another series by Geroulakos et al. document similar outcomes with extraanatomic renal artery revascularization for atherosclerotic renal artery disease. Forty-five hepatorenal and/or splenorenal bypasses were performed in 38 patients for the treatment of renovascular hypertension, renal preservation, or both. There was one postoperative death from myocardial infarction and two cases of early graft P.191 thrombosis. There was a significant decrease in postoperative mean serum creatinine as well as the average number of antihypertensives. Over a median follow-up of 33 months, there were 10 deaths all from cardiac issues.3

COMPLICATIONS Bypass graft thrombosis Intestinal ischemia due to preexisting disease or traction injury to SMA during operative procedure Bleeding from renal, hepatic, splenic anastomosis, ligated renal artery stump, portal vein if injured Acute renal failure requiring temporary or permanent dialysis Pancreatitis, splenic infarction, common duct injury Incisional hernia

REFERENCES 1. Benjamin ME, Dean RH. Techniques in renal artery reconstruction: part II. Ann Vasc Surg. 1996;10(4):409-414. 2. Moncure AC, Brewster DC, Darling RC, et al. Use of the splenic and hepatic arteries for renal revascularization. J Vasc Surg. 1986;3(2): 196-203. 3. Geroulakos G, Wright JG, Tober JC, et al. Use of the splenic and hepatic artery for renal revascularization in patients with atherosclerotic renal artery disease. Ann Vasc Surg. 1997;11(1):85-89. 4. Weaver FA, Kumar SR, Yellin AE, et al. Renal revascularization in Takayasu arteritis-induced renal artery stenosis. J Vasc Surg. 2004;39:749-757.

Chapter 22 Advanced Aneurysm Management Techniques: Open Surgical Anatomy and Repair Elizabeth Blazick Mark F. Conrad

DEFINITION An aneurysm is defined as a permanent, focal dilation of an artery to a size that is greater than 50% of the normal or expected transverse diameter of the vessel. Although dimensions differ slightly for men and women, practically speaking the normal diameter for the abdominal aorta is 2 cm; therefore, the abdominal aorta is considered aneurysmal when it reaches 3 cm in transverse dimensions.

Fusiform aneurysms are the most common configuration and are a symmetric enlargement of the entire vessel, whereas a saccular aneurysm is a focal outpouching that results in an asymmetric bulge of the vessel wall. Aneurysms may occur in virtually any vessel in the body but are most commonly seen in the infrarenal abdominal aortic aneurysm (AAA). The neck is the length of normal aorta between the osteum of the lowest renal artery and the beginning of the aneurysmal aorta. The term juxtarenal is used to describe AAAs that do not involve the renal arteries but because of proximity (0.5 cm over a 6-month period Symptomatic (pain, compression on adjacent structures) Dissection within aneurysm

Table 2: Operative Planning Is a retroperitoneal or transperitoneal approach better? Where is the best location for proximal control? Are there any alternatives should intraoperative findings preclude using this site? • Will clamping involve renal or visceral ischemia? • Will the renal or visceral arteries need to be reconstructed as part of the repair? If so, what size grafts should be used for the bypass?

• Where is the renal vein? Does it pass anteriorly or posterior to the aorta? Will the kidney be taken up or left down? • How will distal control be obtained? Will reconstruction involve the iliac arteries or can the distal anastomosis be to the bifurcation? • What size/type graft should be used?

There are two approaches for the open repair of the infrarenal or juxtarenal aortic aneurysm: transperitoneal or retroperitoneal (FIG 3). Which approach is used for an infrarenal AAA is based on several factors: body habitus (obese patients are often best approached via retroperitoneal), prior surgery (concern for intraperitoneal adhesions), and location of clamp (above the renal arteries may favor a retroperitoneal approach), whereas planned intervention on the right renal or iliac artery would be better approached from the front (transperitoneal).

FIG 3 • Incision for the two approaches to aneurysm repair. A. Transperitoneal and (B) retroperitoneal. The retroperitoneal approach can be modified for higher exposure on the visceral aorta.

TRANSPERITONEAL APPROACH Positioning: The patient is positioned supine on a standard operating room (OR) table with both arms

extended. The area from the nipple line to midthighs should be included in the prep field to allow exposure for a high incision as well as the groins should access to the femoral vessels be needed. The hair is clipped and a towel is placed over the perineum. Any previous incisions within the prep field are marked. A Steri-Drape or Ioban is used to secure the drapes in position. Once in position, check pulse volume recording (PVRs) and/or distal pulses. Incision: A generous midline incision from the xiphoid to the pubis is made and dissected until the peritoneal cavity is entered (FIG 3). It may be necessary to extend the incision cephalad lateral alongside the xiphoid if higher exposure is needed or in emergent situations such as a rupture where immediate supraceliac control is needed. A self-retaining retractor system should then be positioned. We prefer the Omni retractor as the open configuration of the system does not limit the width of exposure. Dissection: Reflect the greater omentum and transverse colon cephalad and pack these structures away in a moistened towel or lap pad on top of the patient’s chest. The small bowel should be retracted to the right and packed within a separate moistened towel. P.195 The small bowel is gently placed behind a self-retaining retractor, taking care not to compromise the superior mesenteric artery (SMA). This exposes the ligament of Treitz, which can be divided along the jejunum to the level of the aorta (FIG 4). Reposition the retractor to allow as much small bowel to be out of the field as possible, and take down the ligament of Treitz with electrocautery, taking care not to injure the bowel. The inferior mesenteric vein is usually ligated during this dissection. This allows access to the infrarenal aorta where the overlying retroperitoneal tissue can be dissected free. Depending on how much aorta is needed for an adequate cuff of the proximal anastomosis, an anterior renal vein may need to be mobilized cephalad, with ligation of the gonadal and/or adrenal vein for better exposure (FIG 5). Exposure of the supraceliac aorta (FIG 6): The maneuver is only needed in cases where high abdominal aortic exposure is needed, such as in a rupture. The left lobe of the liver must be retracted laterally by taking down the triangular ligament. Next, identify and dissect free the gastroesophageal junction after dividing the gastrohepatic ligament, which is most expeditiously done by palpating for the nasogastric tube and applying caudal traction. Division of the gastrohepatic ligament must be done with the thought that a replaced left hepatic artery would be coursing beneath this structure. The esophagus can be retracted to the patient’s left, and this maneuver will expose the aorta. An aortic compressor can be used in extreme circumstances; however, dissection of the aorta circumferentially and surrounding the aorta with a shoestring if the patient’s condition allows is preferable. This exposure, although useful when urgent supraceliac control is needed, will not allow access to the visceral segment of the aorta. In order to gain this exposure, a right or left medial visceral rotation should be incorporated into the dissection. The use of a right medial visceral rotation will allow access to the right renal artery, as well as placing the SMA on 90-degree tension and is useful for clearing a clamp site in those patients with a juxtarenal aneurysm who have very little room between the renals and SMA (FIG 7). The use of a left medial visceral rotation also allows for exposure to the entire visceral segment of the aorta as well as the left renal artery. Care in this approach must be made to avoid injury to the spleen and tail of the pancreas.

FIG 4 • Division of the ligament of Treitz (LOT). After reflecting the colon cephalad and the small bowel to the patient’s right, the LOT can be divided to expose the infrarenal aorta.

FIG 5 • (illustration and photo): Mobilization of the left renal vein. Cephalad or caudal mobilization of the left renal vein to expose the origin of the renal arteries. Ligation of several venous sidebranches may be needed for safe mobilization. (continued) P.196

FIG 5 • (continued)

FIG 6 • Gaining control of the supraceliac aorta. A. Dotted line shows the location for division of the gastrohepatic ligament. B. Once the ligament is divided, the crus is encountered. C. Bluntly divide the fibers of the crus. D. Using fingers for retraction, control of the aorta can be gained with a clamp, although circumferential control is optimal. P.197

FIG 7 • Exposure of the aorta and right renal artery via right medial visceral rotation.

RETROPERITONEAL APPROACH Positioning: Once asleep, position the patient in the lateral position with the left side up at an approximately 60-degree angle (FIG 8). Extend the right arm on an armboard, being sure to leave room for an Omni or other self-retaining retractor post. The upper left arm should be placed on another armboard and padded to prevent neural injury. The bed should be flexed at the patient’s flank to open up the area between the ribs and the anterior superior iliac spine. Position the legs so that the lower leg is straight and the upper leg is bent. Use two pillows as padding between legs. A beanbag can be inflated to keep the patient in place, and use thick cloth tape over the hip to secure the patient on his or her side. Ideally, the patient should be placed on a beanbag; however, blanket rolls can be used anteriorly and posteriorly to further secure the patient. Be sure to allow access to prep from the spine posteriorly to the umbilicus anteriorly and from the nipple line to the groins. All bony prominences and pressure points should be well padded to avoid injury. Use clippers to remove hair within the prep area. Prep from the axilla and nipple line to the upper thigh. Mark all previous incisions and use a Steri-Drape or Ioban over the entire prepped area to secure the drapes. Once in position, check PVRs and/or distal pulses.

Incision: Unless clamping is planned at or above the level of the SMA, a standard retroperitoneal incision over the 11th rib will provide adequate exposure (FIG 3). Carry the incision from the posterior axillary line to the anterior border of the rectus. Avoid entry into the pleural cavity if possible, being cognizant that the further posterior the incision is carried, the higher likelihood this will occur. Divide the transversalis fascia and enter the retroperitoneal space down to but not violating Gerota’s fascia. This space can be more easily identified by resecting a distal segment of the 11th rib, as the tranversalis fascia and transversus abdominal musculature inserts along the inferior border of this rib. It is possible to stay entirely within a retroperitoneal plane; however, if the peritoneum is violated, the abdominal contents can be packed away with retractors or the peritoneum can be repaired with a running 3-0 chromic P.198 suture. The aorta may be approached via an anterorenal (colloquially referred to as “leaving the kidney down”) or retrorenal plane (“taking the kidney up”) (FIG 9). Generally, the aorta is approached via a retrorenal approach unless there is a renal vein running posterior to the aorta. As the retroperitoneal dissection continues, the left ureter should be identified and swept toward the midline and placed behind a retractor to avoid injury during dissection of the aorta. The renal artery is identified and dissected back to its origin to identify the aorta Dissection: The renal artery should be cephalad to the vein, and once this is identified, it can be used as a landmark and dissected back to the aorta.The renal lumbar vein should be identified and ligated to avoid injury and excessive bleeding. Once the origin of the renal artery is identified, a right angle can be placed along the surface of the aorta and the overlying retroperitoneal tissue divided with electrocautery. It is imperative here to get on the aorta and stay on the aorta to avoid excessive bleeding from the retroperitoneal tissue. The aorta is exposed to the bifurcation and can be dissected circumferentially here if a clamp site is planned; however, the left iliac vein can course posterior to the bifurcation and should be avoided. It is often easier to expose an area of the left common iliac artery for clamping and control the right common iliac artery with an occlusion balloon from within. It is unwise to gain circumferential control of the iliacs in this situation as the iliac veins are often adherent to the posterior aspect of the artery and are easily injured, leading to rapid exsanguinating blood loss. Identify and isolate the inferior mesenteric artery (IMA) with a vessel loop. Pay particular attention to identifying and not injuring the ureters, which will eventually cross anterior to the iliac vessels. If necessary and if the incision is placed along a higher rib space, the dissection can be carried caudal to expose the entire visceral segment if need be (FIG 10).

FIG 8 • Positioning for retroperitoneal incision.

FIG 9 • The aorta can be approached in an anterorenal plane (A) or a retrorenal plane (B).

FIG 10 • Exposure of the entire abdominal aorta from a retroperitoneal approach. Here, the kidney is “left down” in an anterorenal plane. All vessels are surrounded with vessels loops.

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AORTIC CLAMPING AND REPAIR Regardless of approach, it is important during circumferential dissection of the aorta to avoid injury to the posterior lumbar arteries, which are usually paired. If they are encountered and require ligation, carefully circumferentially dissect out the artery, tying the proximal side of the vessel, and using another tie, double clip on the distal side prior to dividing. When dissecting on the aorta, care must be taken to minimize aggressive manipulation and subsequent atheroembolization, particularly if preoperative imaging shows extensive mural debris. Choice of graft: There are several choices for conduit during repair. Generally, a polytetrafluoroethylene (PTFE) or Dacron tube graft is sewn from the proximal aorta to the bifurcation. In those patients with extensive bifurcation or iliac disease, a bifurcated graft may be used. If this is the case, the proximal single lumen portion of the graft should be as short as possible to prevent kinking, ideally less than 4 cm. Tunneling the limb to the femoral level should be done only if necessary, and if so, care must be taken to run the graft posterior to the ureter. The aorta can be measured for the appropriate graft with aortic sizers, but often, an estimation of size can be made from the preoperative CTA. Regardless, the majority

of patients can be repaired with an 18- to 22-mm graft (FIG 11). Choosing the site of the proximal anastomosis: This will depend on the quality of the proximal neck of the aneurysm and the vicinity of the visceral vessels. In the most straightforward scenario, an adequate cuff of normal aorta is present below the renals to allow for infrarenal clamping and an end-to-end anastomosis. A suprarenal clamp can be used to provide space to sew to a short infrarenal cuff. If aneurysmal tissue extends to the visceral branches, or if there is significant antherosclerotic disease of the branches, a beveled anastomosis may be required, possibly including an endarterectomy of the origin of a branch vessel or a bypass to the left renal artery (FIG 12). This should be apparent based on careful review of preoperative imaging and planned for well before clamping of the aorta. From the retroperitoneal approach, every effort should be made to incorporate the right renal artery into the anastomosis. In preparation for clamping, the patient should be systemically heparinized at a dose of 70 units of heparin per kilogram and allowed to circulate for 3 to 5 minutes. It is important to communicate with anesthesia prior to clamping and unclamping so they may anticipate and address subsequent hemodynamic shifts. Generally, the systemic pressure should be dropped in preparation for the proximal clamping. If the visceral segment is involved, bulldog clamps should be applied to the visceral vessels prior to aortic clamping to avoid embolization. The proximal clamp is carefully applied and secured with a shoestring around the clamp. The aortic sac is then opened with electrocautery and heavy scissors proximally and distally. Mural debris should be carefully removed to identify all patent lumbar arteries. Distal control can then be obtained with balloon occlusion into each iliac with Foley catheters if external control was not previously done due to calcific disease. All lumbar vessels with back-bleeding into the aorta should be suture ligated with 2-0 silk in a figure-of-eight fashion. In heavily calcified aortas, focal endarterectomies may be necessary for effective ligation of each vessel. Sewing of the proximal anastomoses: There are several ways to complete the anastomosis, and choice is based on a combination of surgeon preference and tissue quality. Regardless of technique, the posterior row of sutures should be done first. Ensure that there is adequate exposure of the proximal aorta; this may require the use of a self-retaining retractor within the opened sac or stay sutures on the edges of the sac. Place the graft on the patient’s chest upside down, so the posterior aspect of the graft lies anteriorly. If the posterior row is to be done in an interrupted fashion, the first mattress suture is placed in the middle of the graft from outside to in, placing a snap on the needled ends of the sutures. Place four more mattresses, two on each side, working your way to the 3 o’clock and 9 o’clock positions on the graft. Care must be taken to ensure there are no gaps between sutures; all travel must be within a mattressed stitch and not between stitches. Once all sutures are placed in the graft, begin placing the aortic sutures from inside to outside on the aorta. The proximal aorta is usually not completely transected and the posterior wall can be used to create P.200 a Creech bite that uses the aortic wall as a pledget. Once all sutures are placed, each individual stitch is pledgeted and tied down snugly. The anterior row is then completed, starting from each side and working your way to the center, such that the anterior-most stitch is the final stitch placed. These are also pledgeted and tied into place. Once the proximal anastomosis is completed, an atraumatic clamp should be applied to the body of the graft, and the proximal aortic clamp slowly released to test for integrity of the repair. Any leaks in the suture line should be addressed at this time, particularly along the posterior row, as this will be inaccessible once the distal anastomosis is in place. It is unwise to attempt to place stitches on a fully perfused aorta, and the proximal clamp should be reapplied if repair stitches are necessary. In addition, pledgets should be used with these stitches. A running anastomosis can also be performed with a 3-0 Prolene and an atraumatic needle. The back row is again began in the middle of the

graft with deep Creech bites on the aorta. The graft can be parachuted in to make the suture line taut. The back row should be inspected to ensure that it is snug and additional sutures are used at the 3 o’clock and 9 o’clock positions to secure the back row and run to the top of the aorta (FIGS 13 and 14). P.201 IMA implantation: Although the IMA can generally be ligated without clinical consequence, there are certain situations where it may be beneficial to reimplant the vessel to avoid bowel ischemic complications. Patients with altered pelvic blood flow, such as those with prior gastrointestinal surgery or occluded hypogastric arteries, should especially be considered for IMA reimplantation. Furthermore, visual inspection of the sigmoid colon prior to closure should be done, and IMA reimplantation done if there appears to be questionable viability of the bowel. Additionally, prior to IMA ligation, an assessment of back-bleeding (and thus the collateral circulation to the IMA territory) should be performed and reimplantation considered in cases where the backbleeding is poor. Creating the distal anastomosis: After the proximal anastomosis is completed and hemostasis is ensured, the graft should be pulled taut to the location of the distal anastomosis (or anastomoses if a bifurcated graft is to be used). The graft should be measured to ensure no redundancy or kinking occurs but not so tight as to put undue strain on the proximal anstomosis. The distal can be done in a running or interrupted fashion, as described previously. When sewing, the assistant should use a forceps to pull the graft distally and remove tension on the anastomosis, decreasing the chance the sutures will be too loose. Flushing and unclamping: Just prior to the completion of the distal anastomosis, the graft will need to be flushed proximally and distally to remove clot, air, and debris. After flushing, irrigate the graft with heparinized saline and complete the anastomosis. Once both anastomoses are completed, communicate with the anesthesiologist that the clamps are ready to be removed. There is often a substantial drop in systemic blood pressure as the lower extremities are reperfused, and they will need to prepare to react accordingly. It is more appropriate to tolerate a slightly longer clamp time and allow the anesthesiologist to regulate the blood pressure accordingly then unclamp a hypotensive patient. As the surgeon slowly unclamps, the assistant can hold manual pressure at the level of the femoral arteries to allow any debris to flush into the pelvis, which may tolerate embolization better due to the extensive collateral network. Pressure is then released on the femoral vessels and systemic pressure is monitored. If there is a substantial hypotensive response, partial or complete reclamping may need to be performed to allow the anesthesia team time to treat the hemodynamics. Once unclamped, inspect the anastomosis and sac for bleeding. There may be new lumbar bleeding as a result of pelvic reperfusion that was not apparent during the graft placement. Diffuse oozing can be treated with Surgicel and Gelfoam. Once unclamped, check pulses and Doppler signals in iliacs and any clamped branch vessels, as well as distal pulses and/or PVRs. If lower extremity PVRs are significantly worse than preoperatively, this should raise concern for embolization and may warrant a groin exploration and thrombectomy. Sac closure: This is especially important during the transperitoneal approach, as an uncommon but disastrous late complication from open aortic surgery is the aortoenteric fistula, which occurs when graft and/or anastomosis erodes into the bowel. To help prevent this, the walls of the now decompressed aortic sac should be closed over the graft, and sewed in a running fashion with a long 3-0 silk or chromic suture. If there is insufficient sac to close, a flap of omentum can be mobilized and placed over the graft prior to returning the visceral to its anatomic location. The sac of the aorta can be a not insignificant source of bleeding, so electrocautery should be used along the cut edge of the sac to ensure hemostasis prior to sac closure, and persistent bleeding should be suture ligated. Drainage and closure: If the pleural cavity was entered, drainage will be required either by use of a red rubber suction catheter placement during diaphragmatic repair or postoperative chest tube placement.

Additional placement of a closed suction Jackson-Pratt (JP) or Blake drain in the peritoneal or retroperitoneal (RP) cavity can be done on a selective basis; we generally place a drain if there is some concern over excessive mobilization near the tail of the pancreas and thought a pancreatic leak may occur, or in coagulopathic patients where ongoing bleeding may be of concern. Special attention should be paid to inspecting the spleen, and we have a low threshold for splenectomy if there is any injury to the organ. The abdominal wall should then be closed in layers.

FIG 11 • A. Tube graft from infrarenal aorta to bifurcation and (B) bifurcated graft from infrarenal aorta to iliac or femoral vessels.

FIG 12 • Beveled anastomosis with bypass to the left renal artery. The suture line runs just inferior to the right renal artery.

FIG 13 • Construction of the posterior row of the proximal anastomosis. Note that the anterior and lateral aspects of the aorta is divided but the posterior wall is left intact in this figure, using “Creech” suturing technique.

FIG 14 • Aortic cuff. The aorta can be totally transected and stay sutures applied in preparation for the anastomosis.

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PEARLS AND PITFALLS ▪ Ideally, proximal clamp time should be less than 30 minutes. It is therefore imperative to have all tools and grafts ready and all team members briefed on the operative plan prior to clamping. However, for an infrarenal clamp, the operator will have several hours if necessary to complete the anastomosis. If the clamp is suprarenal, complications begin with more than 40 minutes of ischemia. ▪ Injury to the common iliac vein or distal IVC during dissection is a potentially lethal complication. It

is important to completely mobilize the vein and perform a primary repair under direct vision. Blind suturing in a bleeding field will only lead to disaster. If exposure cannot be obtained, it is acceptable to transect the overlying artery (aorta or iliac) to allow access to the vein. This is a complication that is much better to avoid than treat. ▪ The ureters can be injured during the transperitoneal or retroperitoneal approach, and every time the retractors are repositioned or as you begin to dissect a new plane, the ureters should be identified.

POSTOPERATIVE CARE Patients should be monitored in an intensive care unit (ICU) postoperatively, with blood pressure goals generally of a systolic blood pressure from 100 to 140 mmHg for a straightforward infrarenal or juxtarenal repair. Blood pressure goals should be higher for thoracoabdominal repairs to promote spinal cord perfusion. Patient may be weaned to extubated as soon as possible after the operation, even in the OR if appropriate. An NGT is kept in place given the bowel manipulation, and this is left in place for the first postoperative day. Although it is not imperative to keep in place until there is full return of bowel function, we will keep in place an additional day if outputs are unusually high. We generally start standing rectal suppositories on the first postoperative day. If there is a chest tube in place, we leave this to suction until removal, which is done when output is less than 150 mL per 24 hours and the chest x-ray (CXR) shows no large effusion. Mobilization should be done as soon postoperatively as possible. These patients will require physical therapy and many will ultimately require inpatient rehab.

OUTCOMES Mortality for an elective, open infrarenal AAA repair is less than 5%, and although the risk increases for those with a juxtarenal or suprarenal repair, our recent experience shows that 30-day mortality in patients with juxtarenal repair is 2.5%. Mortality increases in the instance of an urgent or rupture to as high as 70%.1,5 Patient-specific predictors of postoperative complications include older age, COPD, chronic renal disease (creatinine >1.8) or history of myocardial infarction (MI)/congestive heart failure (CHF).1 Operative-specific predictors of postoperative complications include long OR or clamp times, hypothermia, high blood turnover, and a high perioperative fluid requirement.

COMPLICATIONS Bleeding Infection Splenic injury (consider adding splenectomy to operative consent) Renal failure

MI CVA Spinal cord ischemia (increased risk with suprarenal and thoracoabdominal repairs) Anastomotic breakdown Aortoenteric fistula Pancreatitis

REFERENCES 1. Brewster DC, Cronenwett JL, Hallett JW Jr, et al. Guidelines for the treatment of abdominal aortic aneurysms. Report of a subcommittee of the Joint Council of the American Association for Vascular Surgery and Society for Vascular Surgery. J Vasc Surg. 2003;37:1106-1117. 2. Cronenwett JL, Sargent SK, Wall MH, et al. Variables that affect the expansion rate and outcome of small abdominal aortic aneurysms. J Vasc Surg. 1990;11(2):260-269. 3. Darling RC III, Brewster DC, Darling RC, et al. Are familial abdominal aortic aneurysms different? J Vasc Surg. 1989;10(1):39-43. 4. Strachan DP. Predictors of death from aortic aneurysm among middleaged men: the Whitehall study. Br J Surg. 1991;78(4):401-404. 5. Tsai S, Conrad MF, Patel VI, et al. Durability of open repair of juxtarenal abdominal aortic aneurysms. J Vasc Surg. 2012;56(1):2-7. 6. McFalls EO, Ward HB, Moritz TE, et al. Clinical factors associated with long-term mortality following vascular surgery: outcomes from the Coronary Artery Revascularization Prophylaxis (CARP) Trial. J Vasc Surg. 2007;46(4):694-700. 7. Chaikof EL, Brewster DC, Dalman RL, et al. SVS practice guidelines for the care of patients with an abdominal aortic aneurysm: executive summary. J Vasc Surg. 2009;50(4):880-896. 8. Dawson I, Sie RB, van Bockel JH. Atherosclerotic popliteal aneurysm. Br J Surg. 1997;84(3):293. 9. Johnston KW, Rutherford RB, Tilson MD, et al. Suggested standards for reporting on arterial aneurysms. Subcommittee on Reporting Standards for Arterial Aneurysms, Ad Hoc Committee on Reporting Standards, Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery. J Vasc Surg. 1991;13(3):452-458. 10. Lederle FA, Johnson GR, Wilson SE, et al. The aneurysm detection and management study screening program: validation cohort and final results. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators. Arch Intern Med. 2000;160:1425-1430. 11. Lederle FA, Wilson SE, Johnson GR, et al. Immediate repair compared with surveillance of small

abdominal aortic aneurysms. N Engl J Med. 2002;346(19):1437-1444.

Chapter 23 Advanced Aortic Aneurysm Management: Endovascular Aneurysm Repair—Standard and Emergency Management Vinit N. Varu Ronald L. Dalman

DEFINITION An abdominal aortic aneurysm (AAA) is defined as a localized enlargement of more than 1.5 times the diameter of the most adjacent, proximal uninvolved aorta; by consensus, this represents more than 3.0 cm in most persons. Definitions vary somewhat between men and women, most likely normalized by body surface area or body mass index (BMI). The most common etiology of AAAs is progressive, transmural degeneration of the aortic wall. The full scope of pathogenetic considerations and relevant mechanisms is beyond the scope of this chapter but, in summary, although aneurysm disease shares many important risk factors for aortic and peripheral vascular occlusive disease, important differences exist, and current thinking regarding pathogenesis recognizes that aneurysmal and occlusive disease of the aorta are distinct pathologic processes. Hence, the colloquial term “atherosclerotic aneurysm,” although in common use, is an inaccurate and potentially misleading characterization of the most common clinical presentation for AAA. Risk factors for development, expansion, and rupture are multifactorial1 (Table 1). Smoking is the only modifiable risk factor that has been associated with all three. The risk of AAA rupture increases with progressive diameter enlargement.2 Rupture and subsequent aneurysm-related mortality may be prevented by elective surgical repair, either by open interposition grafting or endovascular aneurysm repair (EVAR). EVAR provides similar long-term survival versus traditional open repair, as well as enhanced perioperative survival. The perioperative survival benefit is sustained for several years following surgery.3 EVAR is now the de facto standard of care for both elective and ruptured AAA repair in patients who are anatomically suited to receive currently available devices.

Table 1: Risk Factors for Aneurysm Development, Expansion, and Rupture Symptom

Risk Factors

AAA development

Tobacco use Hypercholesterolemia Hypertension Male gender Family history (male predominance)

AAA expansion

Advanced age Severe cardiac disease Previous stroke

Tobacco use Cardiac or renal transplant AAA rupture

Female gender ↓FEV1 Larger initial AAA diameter Higher mean blood pressure Current tobacco use (length of time smoking >> amount) Cardiac or renal transplant Critical wall stress—wall strength relationship

AAA, abdominal aortic aneurysm; FEV1, forced expiratory volume in 1 second. From Chaikof EL, Brewster DC, Dalman RL, et al. The care of patients with an abdominal aortic aneurysm: The Society for Vascular Surgery practice guidelines: executive summary. J Vasc Surg. 2009;50(4):880-896.

PATIENT HISTORY AND PHYSICAL FINDINGS Patients may be entirely asymptomatic despite suffering from large, advanced AAAs. Most commonly, AAAs are found incidentally on imaging studies obtained for other reasons. Occasionally, they may be identified by the presence of prominent aortic pulse, proximal to the umbilicus, on physical exam. Less frequently, AAAs may cause distal limb ischemia secondary to embolization, or fulminate congestive heart failure if they rupture into the adjacent inferior vena cava, creating an acute aortocaval fistula. Only 30% to 40% are noted on physical examination, with detection of pulsatile abdominal mass dependent on aneurysm size. As noted by Sir William Osler, prior to the era of ubiquitous availability and use of cross-sectional abdominal imaging in the evaluation of abdominal pain: “There is no disease more conducive to clinical humility than aneurysm of the abdominal aorta.” Patients with a ruptured AAA may present with moderate or extreme back and abdominal pain, syncope, hypotension, and mottling of the lower extremities, in conjunction with progressive abdominal distension. When sufficiently stable to remain conscious and conversant, pain is reproducibly elicited by direct palpation of the abdominal aorta. Many patients with ruptured AAA present in extremis, others with progressively hemodynamic deterioration and pain of several hours duration. Patients may actually linger for several days with “contained” retroperitoneal hemorrhage following AAA rupture. A thorough vascular history should be noted and modifiable risk factors, including smoking, hyperlipidemia, and hypertension, addressed in patients with AAAs. Smoking cessation is recommended to reduce the risk of aneurysm growth and rupture, and statins may also be beneficial in this regard. AAAs occur almost exclusively in the elderly (mean age of repair 72 years of age) and male patients outnumber female by 4 to 6 is to 1.1 When AAA is recognized in younger patients, it is usually in association with hereditary risk, syndromic aortic conditions such as Marfan syndrome, or in the setting of focal aortitis or mycotic aneurysms. The latter tend to occur most frequently in the suprarenal abdominal aorta, at or directly proximal to the origin of the celiac artery, underneath the crus of the diaphragm. Aneurysmal degeneration of the abdominal aorta may also occur late following thoracic and abdominal aortic dissection.

P.204 Factors associated with increased risk of rupture include female gender, large initial diameter, low forced expiratory volume in 1 second (FEV1), current smoking history, and elevated mean blood pressure.

IMAGING AND OTHER DIAGNOSTIC STUDIES Screening decreases aneurysm-related mortality in AAA disease.4 Current guidelines recommend a screening ultrasound for 65- to 75-year-old at-risk individuals, defined as men who have smoked more than 100 cigarettes in their lifetime or men or women with a family history of AAAs.5 Thin-slice computed tomography (CT) imaging, with intravenous contrast injection timed to opacify the abdominal aorta and runoff vessels, remains the standard modality for operative planning. The extent, morphology, and accessibility of the aneurysm via retrograde iliofemoral access determine the suitability for an endovascular repair. Other relevant anatomic considerations include the location and volume of laminar intraluminal thrombus in the region of the “surgical” neck (defined as the length between the lowest renal artery and the start of the aneurysm); angulation of the surgical neck, size and tortuosity of access vessels; presence and significance of anomalous and accessory renal arteries; diameter at the aortic bifurcation; and diameter of the more proximal abdominal aorta (provides useful guidance as to the likely long-term diameter of the surgical neck). For cases of suspected AAA rupture, bedside transcutaneous ultrasonography may be used to detect the presence of intraor retroperitoneal fluid (or blood) or assess for confounding conditions eliciting abdominal pain. When sufficiently hemodynamically stable, however, CT aortography should be obtained to assess for suitability for endovascular repair.6

SURGICAL MANAGEMENT Indications Patients with “symptomatic” AAAs (e.g., pain likely originating from the aneurysm despite absence of retroperitoneal hemorrhage on CT aortography) are at increased risk of rupture and urgent intervention is recommended. Of those AAAs that rupture, more than half will die prior to hospitalization. Of those that undergo attempted operative repair, approximately 50% mortality is to be expected. The latter estimate is highly dependent on hemodynamic conditions, duration of symptoms, and comorbid conditions present at the time of surgery and is not useful in predicting survival of individual patients.1 For asymptomatic AAAs, management is determined by the maximal orthogonal transverse diameter at the time of evaluation or rate of aneurysm enlargement over time. AAAs less than 4.0 cm are at low risk of rupture and should be monitored with serial imaging; those larger than 5.4 cm are at high risk of rupture and should be repaired. Surveillance is recommended for most patients in the range of 4.0 to 5.4 cm, although young healthy patients and especially women may benefit from repair in AAAs between 5.0 and 5.4 cm.1

Preoperative Planning Anatomic measurement obtained from high-quality CT aortography, preferably reconstructed with millimeter or submillimeter slices, is paramount to successful endovascular repair. Ideally, precise diameter and path length measurements are derived from three-dimensional (3-D) reconstruction of the two-dimensional (2-D) source images (via TeraReconTM, OsiriXTM, or similar software). Precision is most essential in determining diameter throughout the surgical neck and common iliac landing zones proximal to the bilateral iliac bifurcations. Graft oversizing of 10% to 20% is typically used

in the region of the surgical neck. Length measurements are obtained from the lowest renal artery to the iliac bifurcation, using path lengths, when available, from image reconstruction software noted earlier. Multiple aortic endografts are approved for use in the United States at the current time, and device selection should be tailored to individualized anatomic requirements. Contraindications to endovascular repair may include inadequate neck length, diameter, and angulation; thrombus volume and distribution in the neck; insufficient iliac artery diameter, and excessive iliac or aortic tortuosity. It is the responsibility of the operating surgeon to ensure that for each selected device, the instructions for use (IFU) are understood and appropriate for the planned repair. Experienced operators, with careful planning, may knowingly place devices in off-label circumstances, depending on the patient-specific anatomic and physiologic risk assessment, with the expectation of reasonably long-term results. In off-label applications, however, the onus is on the surgeon to confirm that sufficient proximal and distal fixation and sealing zones exist to ensure a reasonable result.7 Femoral access must also be evaluated with ultrasound or CT imaging to determine if the patient is a candidate for percutaneous repair. The “preclose” technique (see the following text) can be used for arteriotomy closure for devices up to 21 French (Fr) in diameter. Contraindications to percutaneous repair include calcification of the anterior femoral artery wall, diameter less than 7 mm, the presence of an aneurysmal femoral artery, and excessive scaring at the access site. The superior mesenteric artery (SMA) and celiac arteries should be examined for patency and the presence of flow-limiting stenosis or occlusion; if found, revascularization of the SMA and celiac artery should be considered prior to attempted EVAR, or open repair is considered as an alternative approach. In planning for EVAR, attention must be paid to the status of the inferior mesenteric artery and the total visceral vascularity assessed in terms of consequences of obligate inferior mesenteric artery (IMA) coverage during EVAR. Occasionally, depending on anatomic circumstances, custom fenestration or parallel grafting options may be considered as alternatives, allowing for EVAR management despite the presence of significant celiac or SMA disease. The latter options again, however, should only be considered by operators experienced in these techniques or facile with rapid open conversion when indicated to preserve intestinal perfusion. Facilities are an essential consideration. Fixed imaging is the preferred option for procedural guidance and aortography, preferably when available in a “hybrid” operating room configuration. This is especially true when tolerances are low regarding IFU status and related anatomic considerations. Anesthesia can be either general or local with conscious sedation, depending on the habitus of the patient, their suitability for conscious sedation, and the potential likelihood of open conversion. In our practice, all patients are consented for open conversion, even though in practice this happens in less than 1% of cases.

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ENDOVASCULAR ANEURYSM REPAIR STANDARD Percutaneous Access Using ultrasound guidance to determine the location of the femoral bifurcation and potential presence of anterior calcified atherosclerotic plaque, bilateral common femoral arteries (CFAs) are accessed with 0.018-in micropuncture kits. Femoral arteriography is performed to confirm suitability of the selected access site within the CFA prior to serial dilation. A 0.035-in general purpose wire (e.g., Bentson, Cook Medical, Bloomington, IN) is advanced into the aorta through the micropuncture sheath and 11-cm, 7-Fr sheaths are exchanged over the Bentson into

the external iliac arteries (EIA) under continuous fluoroscopic guidance. Full intravenous anticoagulation is established with unfractionated heparin (at least 100 units/kg) and confirmed by subsequent determination of activated clotting time (ACT) greater than 250 seconds.

Preclose Technique In all circumstances, the surgeon should consult the respective IFUs for all devices employed during these procedures. While the assistant maintains direct compression proximal to the inguinal ligament to maintain hemostasis, the 7-Fr sheaths are individually removed over each respective wire and replaced with a Perclose ProGlideTM (Abbott, Abbott Park, IL) device. This is back-loaded on the wire and advanced until the guidewire exit line on the device. The wire is then temporarily removed and the device advanced until pulsatile blood is visualized through the pilot tube lumen. The first device is turned to the 10 o’clock position and foot plate activated. Holding back tension on the device, the suture is deployed, and the ends are removed from the device and controlled with a padded suture clamp. After the wire is repositioned through the wire port into the aorta under fluoroscopic guidance, the foot plate is released and the device is backed out of the femoral artery. Pressure is reapplied over the puncture site during this maneuver (FIG 1). A second Perclose ProGlideTM (Abbott) device is backloaded on the wire and the aforementioned steps are repeated with the device turned to the 2 o’clock position. After both ProGlidesTM (Abbott) are deployed, the 7-Fr sheath is reformed and replaced over the wire to maintain hemostasis. The suture clamps are positioned consistent with the clockface orientation of each suture placement. The procedure is then repeated for the contralateral femoral access site.

FIG 1 • Preclose technique. Two ProGlidesTM are deployed, one at the 10 o’clock position and the other at the 2 o’clock position before beginning serial dilation maneuvers and deployment of delivery catheters. Once the procedure is complete, and large diameter devices are removed, both knots are seated to close the arteriotomy (see inset). Until closure, the free sutures are controlled on suture boots. Once the procedure is complete, both knots are pushed down to close the arteriotomy.

Delivery and Deployment of Endograft Wire exchange is performed through a guiding catheter (e.g., 100-cm GlidecathTM, Terumo Medical, Somerset, NJ) for a stiffer access wire (e.g., LunderquistTM, Cook Medical). Serial dilation is preformed over the stiff wire, under fluoroscopic guidance, to gently distend and enlarge the respective arteriotomy sites. Following dilation to at least 14 Fr, the primary and secondary access sheaths are advanced under fluoroscopic guidance into the aorta. P.206 The main body endograft is placed up the ipsilateral iliac artery to the level of the renal arteries. Laterality of main body deployment is determined based on the tortuosity and diameter of the access arteries, as

well as the desired angle at which the main body will interface with the renal arteries. The main body should be oriented so that the gate deploys in anterolateral fashion for easy contralateral limb access. The image intensifier should be adjusted to limit parallax by accounting for some degree of anterior angulation (usually in the range of 10%, occasionally more) and lateral angulation in the surgical neck, based on preprocedural assessment from the reformatted CT aortogram (FIG 2A). An Omni Flush catheter (AngioDynamics, Latham, NY) is placed up the contralateral iliac artery to the level of the renal arteries. The gantry position is then confirmed to be appropriate for the patient’s anatomy, ensuring that the image plane is orthogonal to the takeoff of the lowest renal artery. Usually, a “20 for 10” contrast run is performed during breath-hold under magnification views, delivering 10 mL of contrast at a rate of 20 mL per second, to confirm the device position vis-a-vis the renal artery origins. The main body endograft is then deployed according to the IFU, with the proximal fabric margin positioned just below the lowest renal artery. Deployment continues until the contralateral gate is fully open (although techniques may vary between devices). Depending on the device-specific IFU, the main body may be resheathed and repositioned, if necessary, to obtain optimal positioning (FIG 2B). Repeat aortography is performed to ensure adequate placement. The side-hole, aortic flush catheter is withdrawn into the aneurysm through the proximal landing zone, over a wire. If the device uses suprarenal stent fixation, the suprarenal stents are deployed when main body placement is deemed sufficient. Care should be taken to prevent pulling the main body of the endograft down into the aneurysm.

FIG 2 • Delivery and deployment of endograft. A. The main body is brought up the ipsilateral iliac artery to the level of the renal arteries. An Omni Flush catheter is brought up the contralateral iliac artery and an angiogram is performed. B. The main body endograft is deployed under fluoroscopic guidance until the contralateral gate is opened. C. The contralateral gate is cannulated. D. An extension limb is placed proximal to the iliac bifurcation on the contralateral side and the ipsilateral endograft is finished being deployed (one docking limb systems) or an extension limb is placed (two docking limb systems) to the level of the ipsilateral iliac bifurcation.

Gate Cannulation The contralateral sheath is placed 1 to 2 cm distal to the contralateral gate. Using an OmniflushTM (Angiodynamics) or GlideTM catheter (Terumo), the gate is cannulated with an angled GlidewireTM (Terumo). When successful, the Omniflush catheter should be exchanged over a wire and reintroduced into the endograft. The tip is allowed to reform by withdrawing the wire and the curled flush catheter is spun 360 degrees several times to confirm gate cannulation. Failure to confirm this step may result in

deployment of the contralateral limb outside of the gate, likely generating “endotrash” (e.g., graft limb free in the aneurysm, outside the main body, which will not remain in circulation) (FIG 2C). If the contralateral gate cannot be successfully cannulated using standard guidewire and catheter techniques (different-shaped catheters should be employed, as well as repositioning the sheath in relation to the contralateral gate), cannulation may be accomplished by advancing a snare up the contralateral sheath into the aneurysm and engaging the main body endograft bifurcation with a Sos Omni or similar curved catheter. The ipsilateral wire is then advanced through the gate, to be snared from the contralateral side. Once the wire is withdrawn through the contralateral sheath, a catheter may be back-loaded and advanced into the main body, which in turn allows an exchange to a stiffer wire through the gate. When necessary, a wire can also be advanced from brachial artery access for the same purpose.

Limb Extension Retrograde iliac angiography is performed through the sheath, with the gantry position in the contralateral oblique position. This will identify the origin of the internal iliac artery. Once this is confirmed, distance from the gate to the internal iliac is measured using a marker catheter and an appropriately sized limb is chosen. P.207 For three-piece bifurcated devices (e.g., TriVascular OvationTM, Cook ZenithTM), this procedure has to be performed on both sides. Optimal limb deployment maintains sufficient contact with the gate to maintain seal (see respective IFU) and sufficient distal coverage to completely exclude the common iliac artery without impinging on the origin of the internal iliac artery (FIG 2D). Occasionally, when the distance required for proper limb placement does not precisely correlate with the sizes available, the next size-longer limb may be deployed into the gate and slowly along its length. During deployment (once out of the gate), continued upward pressure on the deployment handle is maintained to encourage the graft to take a somewhat more serpiginous route, taking up some of the additional leak. Partial coverage of the ipsilateral internal iliac artery orifice is also appropriate when deployment can be precisely monitored in the contralateral oblique gantry position.

Balloon Molding An appropriately sized semicompliant balloon (e.g., CodaTM, Cook Medical) is expanded with dilute contrast solution at all three landing zones and overlap areas within the gate(s) as appropriate for the specific device (FIG 3). When existing common iliac artery stenosis is present, kissing balloons should be deployed to obtain optimal internal diameter and prevent limb kinking or occlusion. Similarly, the aortic bifurcation should also be dilated when necessary. Occasionally, self-expanding bare metal nitinol stents may be deployed at areas of stenosis or from the distal limb into external iliac artery, to prevent kinking of the endograft or native external iliac artery distal to the device.

Completion Arteriography Completion arteriography is performed with higher volume and longer injection time to completely fill the endograft, ensure limb patency, and identify endoleaks (FIG 4). All type I or III endoleaks, when present at the end of the case, should be addressed with additional maneuvers to ensure seal. This may include deployment of proximal endograft cuffs, prolonged molding balloon inflation time, or, on occasion, placement of embolism coils in recalcitrant leaks. When small leaks persist, even when anatomic coverage seems adequate, anticoagulation should be reversed and sheaths removed with the plan for follow-up CT aortography within a few days. Care should be taken to carefully evaluate the nature of all leaks (type, volume, location in regard to lumbar branches, status of graft limb deployment, adequacy of

molding, etc.) before secondary interventions are considered for persistent leaks. The majority of type II endoleaks resolve in the first year. In our practice, we never resort to deployment of a large diameter, balloonexpandable stent in the proximal neck—accurate sizing and deployment of this stent may be difficult and “stretching” the proximal orifice of the main body in this way may damage the graft, without sufficient assurance that the proximal type I leak will be adequately addressed.

FIG 3 • Balloon molding. A semicompliant balloon is inflated at proximal and distal landing zones as well as at all overlapping endografts.

Closure The contralateral sheath is removed over the wire and manual pressure is held. The previously placed preclose polypropylene sutures are deployed sequentially in each access site and cinched down with a knot pusher over a wire. When initial hemostasis appears adequate, the wire is removed and slightly more pressure is applied to the knot pusher. After both sutures are deployed in one groin, determination is made as to which of the two appears to provide more effective hemostasis and manual pressure is held to this suture for 5 additional minutes. This is repeated for the ipsilateral side. Procedural anticoagulation is reversed once all sheaths and clamps are removed. It is essential to wait for final introducer device removal before reversing the anticoagulation, because the large diameter sheaths used to deliver EVAR devices may almost entirely occlude the ipsilateral external iliac artery, causing potentially catastrophic graft limb and iliac artery thrombosis in the absence of full anticoagulation. P.208

FIG 4 • Completion arteriography. Special attention is paid to ensure the renal and iliac arteries are patent, as well as to identify if an endoleak is present. The endograft itself should be scrutinized for any evidence of limb kinking. A. Renal artery patency confirmed. B. No Type 1A endoleak confirmed. C. External and internal iliac artery patency confirmed and endograft itself should be scrutinized for any evidence of limb kinking. D. No type 1B, 2, 3, or 4 endoleak identified with delayed imaging.

ENDOVASCULAR ANEURYSM REPAIR FOR RUPTURED ANEURYSMS, OR REVAR Percutaneous Access Bilateral CFA access is obtained under local anesthesia. The preclose technique (described in the previous section) can be employed when time and conditions permit, but if not possible, the case can proceed percutaneously initially, with conversion to open femoral closure when the endograft is fully deployed and internal bleeding has stopped. Rapid catheter and guidewire exchanges are performed, with sheath upsizing as noted in the previous section. The use of intravenous anticoagulation is controversial in this setting—again it is highly

dependent on the hemodynamic status of the patient, presence of active bleeding, and existing consumptive coagulopathy. Often when treating ruptured aneurysms, the case begins without anticoagulation, which is subsequently instituted once the main body and extension limbs are deployed. In the case of rupture procedures, preoperative CT aortography may not exist or may not provide sufficient P.209 anatomic detail to guide deployment. In this circumstance, catheter arteriography with a marker flush catheter should be employed to determine path lengths, landing zones, and optimal graft sizing.

Aortic Balloon Control Following access and wire exchange, a LunderquistTM (Cook Medical) or similar stiff wire is advanced into the aorta, over which a 14-Fr × 55-cm braided sheath is advanced to the level of the renal arteries. Once localization is confirmed, the sheath is sutured to the skin at the access site. A semicompliant balloon (CodaTM, Cook Medical) or similar aortic occlusion balloon is directed to a position immediately proximal to the visceral arteries under fluoroscopic guidance (FIG 5). Once positioned, it can be maintained in the deflated site until or unless the patient’s hemodynamic status requires inflation and aortic occlusion. Once bilateral therapeutic sheath access is obtained and the deflated occlusion balloon is positioned properly, general anesthesia may be induced.

Endograft Delivery and Deployment Aortography is performed through the contralateral sheath below the balloon to localize the origins of the renal arteries. The main body endograft is placed up the ipsilateral sheath to the level of the renal arteries. It should be oriented so that the gate deploys in anterolateral fashion. The main body endograft is then deployed according to the IFU, just distal to the lowest renal artery. Deployment continues until the contralateral gate is fully deployed (FIG 6). The ipsilateral limb of the endograft is cannulated and the sheath advanced into the main body of the endograft. A second Coda balloon is placed in the ipsilateral sheath and inflated in the main body (FIG 7). The first balloon is deflated and removed through the contralateral sheath. Balloon placement should be performed in such a way that time without balloon coverage is kept to an absolute minimum. Retroperitoneal hemorrhage can continue at a rapid rate throughout this procedure, and in the absence of external bleeding, neither the surgeons nor the anesthesiologists may appreciate true magnitude of blood loss and circulatory reserve. Under these circumstances, hemodynamic collapse can be precipitous and, unfortunately, calamitous, unless an occlusion balloon is properly positioned and immediately inflated at the first indication of rapid hemodynamic deterioration.

FIG 5 • Aortic balloon control for REVAR. A semicompliant balloon is placed up the contralateral iliac artery proximal to the celiac trunk. It can be inflated depending on hemodynamic instability.

FIG 6 • Main body deployment for REVAR. After an angiogram is performed to identify the renal arteries and aortic neck, the main body is deployed up the ipsilateral iliac artery. This can be done with the semicompliant balloon inflated.

Figure 7 • Balloon exchange and gate cannulation for REVAR. The entire ipsilateral gate is deployed prior to contralateral gate cannulation. A second semi-compliant balloon is placed up the ipsilateral endograft limb (top of image) and placed into the main body of the endograft. It can be inflated depending on hemodynamic instability. The first semi-compliant balloon is removed and the sheath is brought to distal to the contralateral gate to prepare for gate cannulation. Retrograde angiography with a marking catheter is performed through the contralateral sheath to identify the iliac bifurcation and desired limb extension length. P.210

Gate Cannulation Gate cannulation proceeds in a standard fashion during REVAR.

Limb Extension Limb extension proceeds in a standard fashion during REVAR. Time awareness is critical during standard EVAR steps to ensure that aneurysm sealing is accomplished in the most expeditious manner possible.

Balloon Molding CodaTM balloon (Cook Medical) molding is performed at all seal zones to optimize hemostasis. Only after molding is complete is hemostasis assured.

Completion Aortography Completion aortography is performed as previously described. Attention should be paid to all the usual considerations, including presence and nature of endoleaks, iliac limb or arterial kinking, sufficient overlap in the landing zones to meet IFU, and so forth (FIG 8).

FIG 8 • Completion aortography for REVAR.

Closure Closure proceeds as indicated for standard EVAR, with caveat that if ProGlides were not deployed prior to percutaneous access, then surgical incisions will need to be made to expose the femoral artery sites for control and closure under direct vision as the therapeutic sheaths are withdrawn.

PEARLS AND PITFALLS Access

▪ Ultrasound guidance is essential to limiting access complications. Visualize the needle tip entering the anterior artery wall, in an area deemed appropriate for access.

Gate cannulation

▪ In general, main body should be advanced through the more tortuous of the two iliac arteries to allow a more “straight shot” for the contralateral gate cannulation. This preference is not always practical, however, and laterality may need to be decided based on more practical considerations (e.g., Is the tortuosity sufficient to prevent main body positioning and deployment altogether?).

Tortuous iliacs

▪ Perform the completion aortogram with soft catheters instead of stiff wires in place. Stiff wires may straighten out a tortuous vessel, which may end up kinked when the wires are removed and lead to limb occlusion. Also, retention of stiff wires at the time of completion aortography may mask the development of type I proximal

endoleaks, which may develop situationally when stiff wires are removed. Closure

▪ Tie down the sutures of the closure device with the wire in place. If there is still significant bleeding, either deploy another closure device or place an occlusive sheath and proceed with open conversion of the femoral artery closure under more controlled circumstances.

Ruptures

▪ Outcomes are vastly improved when REVAR protocols are established and practiced. Abdominal compartment syndrome is a real and frequent complication following REVAR—if there is any indication that ventilation pressures are rising or abdominal pressures are significantly elevated at the end of the procedure by measuring bladder pressure, strong consideration should be given to decompressive laparotomy at the initial setting.

POSTOPERATIVE CARE Patients should remain supine for a minimum of 3 hours and are free to ambulate thereafter. Most elective EVARs can be discharged on postoperative day 1 or 2. For cases well within the IFU, same-day surgery is now a reality and can safely be offered to patients who can remain in reasonably close proximity to the hospital the evening after surgery. Following REVAR, consideration should be given to decompressive laparotomy whenever abdominal pressures are elevated at the end of the initial procedure. When decompressive laparotomy is performed, free peritoneal blood should be evacuated but retroperitoneal hematomas should not be explored or evacuated. Abdominal wound suction systems should be deployed to control drainage and provide a moist environment for intestinal viability. Dressing changes should be performed daily or every other day until the wound can be safely closed. Initial postprocedural CT aortography is performed at 1 month to document presence or absence of endoleaks P.211 and graft position and confirm visceral perfusion (FIG 9). Follow-up imaging is performed with either ultrasound +/− noncontrast CT scanning or by CT aortography, based on the last known status of endoleaks (presence or absence), symptomatic status, and comorbid conditions such as chronic renal insufficiency. In general, we prefer serial ultrasound evaluations, with CT scanning reserved for aneurysms which are enlarging following endografting or evidence of significant changes in endoleak volume or location.

FIG 9 • Postoperative imaging. 3-D reconstruction of a CT aortogram in a patient who have undergone successful EVAR at 1 month follow-up.

OUTCOMES All-cause mortality is similar in patients undergoing open or EVAR for AAA at 2 years.3,8,9 There is higher perioperative survival in patients undergoing EVAR, which is sustained for several years.3 The loss of this is due to late ruptures in the EVAR group. Secondary interventions are similar in open and EVAR.3

COMPLICATIONS Endoleak

Delayed rupture Renal dysfunction Thromboembolism Limb occlusion Colon ischemia Abdominal compartment syndrome (ruptured EVAR)

REFERENCES 1. Chaikof EL, Brewster DC, Dalman RL, et al. The care of patients with an abdominal aortic aneurysm: the Society for Vascular Surgery practice guidelines: executive summary. J Vasc Surg. 2009;50(4): 880-896. 2. Lederle FA, Johnson GR, Wilson SE, et al. Rupture rate of large abdominal aortic aneurysms in patients refusing or unfit for elective repair. JAMA. 2002;287(22):2968-2272. 3. Lederle FA, Freischlag JA, Kyriakides TC, et al. Long-term comparison of endovascular and open repair of abdominal aortic aneurysm. N Engl J Med. 2012;367(21):188-197. 4. Lindholt JS, Norman PE. Meta-analysis of postoperative mortality after elective repair of abdominal aortic aneurysms detected by screening. Br J Surg. 2011;98(5):619-622. 5. Guirguis-Blake JM, Beil TL. Ultrasonography screening for abdominal aortic aneurysms: a systematic evidence review for the U.S. Preventive Services Task Force. Ann Intern Med. 2014;160(5):321-329. 6. Mehta M. Endovascular aneurysm repair for the ruptured abdominal aortic aneurysm: the Albany Vascular Group approach. J Vasc Surg. 2010;52(6):1706-1712. 7. Lee JT, Ullery BW, Zarins CK, et al. EVAR deployment in anatomically challenging necks outside the IFU. Eur J Vasc Endovasc Surg. 2013;46(1):65-73. 8. De Bruin JL, Baas AF, Buth J, et al. Long-term outcome of open or endovascular repair of abdominal aortic aneurysm. N Engl J Med. 2010; 362:1881-1889. 9. Greenhalgh M, Allison DJ, Bell PRF, et al. Endovascular versus open repair of abdominal aortic aneurysm. The United Kingdom EVAR Trial Investigators. N Engl J Med. 2010;362:1863-1871.

Chapter 24 Advanced Aneurysm Management Techniques: Management of Internal Iliac Aneurysm Disease W. Anthony Lee

DEFINITION Iliac aneurysm is defined as an iliac artery whose diameter is 20 mm or more. Iliac aneurysms are present in up to 20% of abdominal aortic aneurysms,1 and common iliac aneurysms occur far more frequently than internal iliac aneurysms. Isolated iliac aneurysms represent less than 5% of all aortoiliac aneurysms. External iliac aneurysms are extremely rare and mostly either associated with underlying connective tissue disorders or represent traumatic pseudoaneurysms.

DIFFERENTIAL DIAGNOSIS Differential diagnoses of iliac aneurysm are limited to true degenerative aneurysms, which are most common; mycotic, traumatic, or surgical pseudoaneurysms; or aneurysmal enlargement of the false lumen from a primary dissection.

PATIENT HISTORY AND PHYSICAL FINDINGS Most iliac aneurysms are clinically silent (asymptomatic). Rarely, in very thin individuals with large aneurysms, a pulsatile aneurysm may be palpable on physical examination. Even more rarely, a patient being evaluated for hydroureter may be determined to have an iliac aneurysm. Ureteral obstruction in this circumstance derives from perianeurysmal inflammation (similar to retroperitoneal fibrosis) rather than mechanical compression by the aneurysm.

IMAGING AND OTHER DIAGNOSTIC STUDIES Although a plain abdominal x-ray can detect an aortoiliac aneurysm if there is heavy mural calcification, the most common imaging modalities include ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). Thin-cut (1 mm), intravenous contrast-enhanced, spiral CT (CT arteriogram) represents the “gold standard” for diagnosis and anatomic evaluation of abdominal aneurysms. Even in patients with stage III/IV chronic kidney disease, high-quality imaging may be obtained relatively safely using reduced volumes of isoosmolar, nonionic contrast with multidetector (32, 64, 128, or 220) scanners, particularly following preprocedural intravenous hydration. The CT dataset is rendered into three-dimensional (3-D) images for dimensional postprocessing, a critical requirement for complex endovascular case planning. Conventional arteriography adds little to the identification and analysis of iliac aneurysms; penetrating ulcers may appear like saccular aneurysms, and large aneurysms with circumferential mural thrombus may appear to have a normal contour.

SURGICAL MANAGEMENT

In general, iliac aneurysms are repaired when they reach 30 mm in diameter, become symptomatic, or rupture. Due to the relatively inaccessible location of iliac aneurysms, situated deep in the pelvis, as well as densely adherent pelvic veins posterior to the arteries and frequent co-occurrence of calcific occlusive disease, conventional surgical repair is challenging and fraught with risk of significant hemorrhage. Thus, evolving endovascular methods of repair have largely supplanted open surgical reconstruction. A variety of off-label devices and hybrid techniques have been applied to iliac aneurysm management. The variability derives, in large part, from uncertainty regarding the need to preserve antegrade internal iliac artery flow in most patients. Indications for internal iliac preservation remain controversial due to the added complexity, cost, and uncertain benefit derived from such procedures; analysis of the relative merits of intentional unilateral occlusion versus preservation in the management of iliac aneurysm disease is beyond the scope of this chapter.

Preoperative Planning As in all things endovascular, high-quality imaging is critical for precase planning and, as previously mentioned, CT arteriography is optimal for this purpose. Using a combination of axial imaging and 3-D postprocessing, complete evaluation should, note the following: Locations, diameter, and length of proximal and distal landing zones Iliac artery tortuosity and angulation Presence and severity of associated occlusive disease Ipsilateral and contralateral internal iliac artery patency Status of the ipsilateral deep femoral artery Concomitant abdominal or thoracic aortic pathology In general, landing zones are sited in nonaneurysmal arterial segments, manifesting minimal occlusive disease, with relative absence of angulation or tortuosity. The allowable diameter range for treatment may vary, depending on the particular device to be deployed. In all circumstances, reference should be made to the “Instructions for Use” included in the package insert. Device selection is based on the need for durable aneurysm exclusion and endograft fixation, accomplished with the fewest component pieces possible. This chapter focuses on endovascular and hybrid management strategies for the iliac bifurcation in the context of large common or internal iliac aneurysms. Standard techniques suffice for management of smaller (2 mm) between the two arteries. Also, the durability of this technique is not well established and may be limited by the propensity of the covered stent to back out of either the origin or destination artery or kink. This technique also requires advanced catheter and guidewire skills and a large device inventory to reliably complete the procedure. [Alternate technique] More recently, a variation of the chimney (parallel) stenting technique has been described for complete endovascular repair of common iliac aneurysms.4 In this technique, the proximal brachial artery is exposed through an axillary incision to allow safe introduction of a long (90 cm) braided 9-Fr sheath. Briefly, after the bifurcated main body endograft is deployed, the long 9-Fr sheath is advanced from the left brachial artery, through the main body, and positioned into the ipsilateral common iliac artery. The internal iliac artery is catheterized, followed by wire exchange for a stiff wire. A covered self-expanding stent graft (e.g., Viabahn®), sized for the target internal iliac artery diameter, is deployed

from the ipsilateral iliac gate to the internal iliac artery landing zone. A second covered selfexpanding stent graft is advanced from the ipsilateral femoral artery access retrograde into the aneurysm and proximal external iliac artery and deployed at the same level as prior internal iliac artery stent graft. Both stent grafts are expanded within the ipsilateral iliac limb of the aortic endograft using a kissing-balloon technique. This procedure can be repeated for the contralateral side in cases of bilateral common iliac aneurysms ( FIG 12). Care should be taken during this maneuver to deploy each stent graft sequentially, rather than simultaneously, in order to position the covered stents accurately relative to each other. [Alternate technique] Although only available under an investigational device exemption (IDE), U.S. Food and Drug Administration (FDA)-approved clinical trial at the current time, an iliac branch device (IBD) is under P.219 development for total endovascular repair of common iliac aneurysms (FIG 13). Briefly, this bifurcated device is inserted ipsilateral to the common iliac aneurysm prior to main body deployment. It is designed to be used in conjunction with a standard bifurcated aortic endograft. The partially constrained branch in the investigational device and adjacent internal iliac artery are catheterized from the contralateral side employing a preloaded catheter in the delivery system and cross-femoral guidewire access. A bridging covered stent is advanced from the branch to the internal iliac artery. Following this, a standard bifurcated endovascular aneurysm repair is completed in the usual manner.5

FIG 7 • In this instance, the patient had bilateral common iliac aneurysms. The right side was large and left was smaller. The right internal iliac artery was occluded and the iliac limb extended to the external iliac artery. The bell-bottom technique was able to be used for the smaller left common iliac aneurysm because it was only 24 mm.

FIG 8 • In some patients, the distance between the umbilicus and the symphysis pubis may be quite short. If so, the longitudinal segment of the incision is extended more inferiorly than depicted in this diagram. The most important technical point of this exposure is to place the incision sufficiently medially as the lateral border of the rectus sheath is not palpable and there are no obvious surface landmarks.

FIG 9 • When the incision is properly positioned, the iliac bifurcation should be located directly in the center of the wound. The common iliac aneurysm is minimally exposed to allow the stump of the divided internal iliac artery to be safely oversewn.

FIG 10 • An 8-mm graft is anastomosed to the distal end of the internal iliac artery first. Due to the deep nature of this artery, this anastomosis can be difficult. An open (“parachute”) anastomotic technique can be helpful in visualizing the suture line throughout placement. The distal anastomosis is tested for hemostasis and any leaks completely repaired before the proximal anastomosis is performed, as the former may be difficult to see once the latter is completed. The external iliac anastomosis is performed at least 5 cm distal to its origin along its posteromedial aspect.

FIG 11 • Note that an endovascular external-to-internal iliac bypass has been created on the right side which also excludes the common iliac aneurysm. The durability of this bypass is compromised given its reliance on retrograde perfusion through the femoral-femoral bypass graft, the angulated nature of the graft position, and the propensity for one or both ends to “back out” of the origin and target arteries, given sufficient time, pressure, and movement.

FIG 12 • Like all “chimney” techniques, the proximal seal is dependent on the length of the parallel segment. In this instance, it should be more than 5 cm to promote thrombosis of the “gutters” between the parallel stents. It is not uncommon for a small type III endoleak to be seen on the completion angiogram with the patient anticoagulated.

FIG 13 • This figure depicts the IBD used in the repair of a left common iliac aneurysm. A covered stent is required to bridge the iliac branch to the native internal iliac artery. Although this bridging stent is typically delivered from the contralateral side, it may also be introduced through the left brachial artery.

PEARLS AND PITFALLS Choose the right procedure for the right patient.

▪ Although perfusion is optimally maintained to at least one internal iliac artery, preservation should be attempted selectively, weighing the risks and benefits of potential ischemic complications associated with intentional occlusion vs. the additional complexity and long-term durability issues associated with preservation techniques.

External-to-

▪ Make sure the longitudinal segment of the skin incision is sufficiently medial to

internal iliac bypass exposure

the lateral edge of the rectus to accommodate a single layer fascial closure. The preserved rectus muscle provides a natural barrier against postoperative abdominal wall hernia formation.

Use a crossover introducer sheath for internal iliac embolization.

▪ The cross-over sheath allows for intermittent contrast injection and stabilization of the embolization catheter. Internal iliac sheath access also minimizes the probability that deployed coils may reflux retrograde into the axial iliac circulation, requiring often prolonged and frustrating attempts at retrieval.

Pelvic bleeding

▪ The internal iliac vein is posterior and adherent to the artery and may be the source significant, unanticipated hemorrhage if injured during circumferential arterial dissection.

Inflow to the internal iliac bypass

▪ Choose a site on the external iliac artery sufficiently distal to its origin so that the stent graft can land in a segment free from kinking and prevent subsequent development of an ipsilateral type Ib endoleak.

POSTOPERATIVE CARE Postoperative care is similar to a standard endovascular aneurysm repair. A complete blood count and a basic metabolic panel are checked the following morning. If the procedure was performed entirely using endovascular techniques, oral intake is started immediately, Foley catheter is removed, and patient is encouraged to ambulate and discharged on following postoperative day. If the procedure involved a surgical internal iliac revascularization, the patient is started on clear liquids and advanced as tolerated. The retroperitoneal approach is not typically associated with a clinically significant ileus, and the muscle-sparing exposure is well tolerated. Patients may be discharged typically on the second postoperative day.

OUTCOMES Ipsilateral hip and buttock claudication develops in as many as 40% of patients following acute internal iliac artery occlusion. Fortunately, more severe forms of postprocedural pelvic ischemia, although potentially lethal, occur extremely rarely. Although claudication symptoms, when present, are reported to improve within 6 months following P.220 the procedure, this improvement may be attributable to lifestyle alteration (e.g., walking less) rather than collateral vessel formation. It is generally agreed, however, that complete symptom resolution rarely occurs. Internal iliac bypass grafting (surgical or endovascular) effectively maintains pelvic perfusion, with excellent longterm patency. Most patients enjoy a symptom-free postoperative course in perpetuity. Thus, in active individuals, as a general recommendation, internal iliac circulation should be preserved whenever possible.

COMPLICATIONS Complications for management of common iliac aneurysms can be a result of internal iliac revascularization or occlusion techniques. The main complication associated with revascularization is bleeding. This can occur intraoperatively from venous injury and/or postoperative anastomotic or other arterial sources. Other less common complications include ureteral injury, bowel injury, ipsilateral leg ischemia, and early graft thrombosis. Complications associated with acute occlusion of internal iliac artery include the spectrum of ischemic symptoms ranging from hip and buttock claudication to more severe forms such as perineal necrosis, ischemic sacral plexopathy, and vasculogenic impotence. The internal iliac artery serves as an important outflow branch in maintaining patency of the iliac limb after endovascular aneurysm repair. Iliac limbs whose distal landing zone is placed in the external iliac artery may have an increased risk of thrombosis. However, this is not an indication for any additional antiplatelet or anticoagulation treatments beyond what is customary.

REFERENCES 1. Armon MP, Wenham PW, Whitaker SC, et al. Common iliac artery aneurysms in patients with abdominal aortic aneurysms. Eur J Vasc Endovasc Surg. 1998;15(3):255-257. 2. Boules TN, Selzer F, Stanziale SF, et al. Endovascular management of isolated iliac artery aneurysms. J Vasc Surg. 2006;44(1):29-37. 3. Lee WA, Nelson PR, Berceli SA, et al. Outcome after hypogastric artery bypass and embolization during endovascular aneurysm repair. J Vasc Surg. 2006;44(6):1162-1168. 4. Lobato AC. Sandwich technique for aortoiliac aneurysms extending to the internal iliac artery or isolated common/internal iliac artery aneurysms: a new endovascular approach to preserve pelvic circulation. J Endovasc Ther. 2011;18(1):106-111. 5. Parlani G, Verzini F, De Rango P, et al. Long-term results of iliac aneurysm repair with iliac branched endograft: a 5-year experience on 100 consecutive cases. Eur J Vasc Endovasc Surg. 2012;43(3):287-292.

Chapter 25 Occlusive Disease Management: Isolated Femoral Reconstruction, Aortofemoral Open Reconstruction, and Aortoiliac Reconstruction with Femoral Crossover for Limb Salvage Nathan Itoga E. John Harris Jr.

DEFINITION Aortoiliac occlusive disease falls under the umbrella of peripheral artery disease where atherosclerosis and chronic plaque accumulation leads to diminished blood supply to distal arterial beds. The aortic bifurcation near the level of the L4 disc space is one of many areas of decreased shear stress and is an area of early atherosclerosis. Peripheral arterial disease (PAD) is usually classified into inflow and outflow disease. The infrarenal aorta and iliac vessels are of larger caliber and are classified as inflow vessels. The infrainguinal outflow from the common femoral artery is via the profunda femoral and superficial femoral arteries. The patterns of arterial stenosis and occlusion can be broken up into five types (Table 1). When a combination of both inflow and outflow disease exists, treatment is focused on the aortoiliac system first or femoral artery occlusive disease. Outflow occlusive disease is addressed in Chapters 26, 27 and 28, 31, 32 and 33.

Table 1: Type of Lower Extremity Disease Patterns Distribution

Notes

Type 1

Confined to the distal infrarenal aorta and common iliac arteries

10% of disease patterns— found in younger female patients. Long-term patency after bypass is lower when done in patients 10 mmHg) after angioplasty, recurrent stenosis, occlusion, or to prevent or limit postangioplasty embolization of plaque. Localization: A stent is typically deployed to span the distance between relatively healthy artery proximal and distal to the target lesion. “Healthy” is a relative term in this sense, and care should be taken to limit stent coverage to the minimal distance required to achieve an optimal result. Long lesions in the SFA are the most commonly stented segment, but be aware that stents in the distal superficial femoral and popliteal arteries may be damaged by stress from knee flexion (FIG 11). Excessive P.276 stent coverage may accelerate long-term restenosis and luminal compromise, regardless of the degree of initial success or the type or size of deployed stent. Sheath size: Most stents for infrainguinal deployment require a 6- or 7-Fr sheath. Refer to the individual instructions for use for each individual device. Deployment: Most infrainguinal nitinol stents are deployed using a pin and pull maneuver that retracts the cover from the constrained stent and the underlying mandrel. A ratcheting mechanism may also be integrated into the deployment process. Typically, these may be removed for basic pin/pull deployment if the ratchet becomes jammed or disabled. After deployment, completion angioplasty is performed to bring the stent to profile. Complications of stent deployment: Acute: arterial dissection, occlusion, rupture, stent migration or embolization, embolization of atherosclerotic material, thrombosis Chronic: intimal hyperplasia, recurrent stenosis, infection, stent damage, thrombosis

FIG 11 • Stent placement. A. The patient represented by these arteriograms presented with a right foot Rutherford 5 gangrene. Arteriography demonstrated several mid-SFA stenoses. B. The distal SFA and proximal to mid-popliteal arteries were occluded. C. The SFA stenoses were treated with balloon angioplasty and the sheath was advanced distally so that its tip was close to the occlusion. D. A chronic total occlusion (CTO) catheter is used to support the guidewire in crossing the lesion and the location in the true lumen is confirmed. E. After balloon angioplasty, there was a significant dissection and residual stenosis. F. A self-expanding nitinol stent was placed for mechanical support of the arterial wall and to enhance immediate patency of the reconstruction.

STENT GRAFTS Nitinol-based, flexible stent grafts may be deployed over long and calcified SFA lesions as an alternative to bare metal or drug-eluting stents. As a general rule of thumb, the longer and more complex the target lesion(s) and length of required coverage, the more suitable the indication for covered stent placement. Stent grafting may require exchange of a 0.035-in wire system for smaller guidewires (e.g., 0.025 in or 0.018 in); the operator is again cautioned to refer to the instructions for use for each device considered for placement. Stent grafts must be deployed over the specific guidewire adequate for the stent graft. Sheath upsizing may also be required, depending on the diameter selected. Choosing a larger sheath at the outset will minimize the need for awkward or inefficient sheath exchange after the procedure is well underway. Aggressive predilatation is also often necessary in order to create sufficient space for bulkier covered stent to pass the lesion prior to deployment. Similar to bare metal stents, covered stent

deployment is usually followed by completion angioplasty to bring the covered lumen to profile (FIG 12). Relative advantages of stent grafting, compared to bare metal stents, include the ability to create an entirely new lining for a disease arterial segment. This coverage obviates the possibility of in-stent stenosis within the graft. However, experience has shown that unlike surgically placed prosthetic bypass grafts, covered stents in the superficial femoral and popliteal arteries tend to incite restenosis at the proximal end. Thus, placement usually requires coverage up to the origin of the SFA. Any uncovered artery in this region is likely to develop critical restenosis. Disadvantages include the necessary coverage P.277 of all collateral vessels encompassed in the covered segment, as well as the increased risk for graft infection inherent in fabric-covered metal stents. Also, although some stent grafts are heparin-bonded, the thrombogenicity of covered stents varies directly with the length of segment covered, such that complete SFA coverage from the origin to the adductor canal necessitates long-term oral anticoagulation therapy in patients treated in our practice. Anticoagulation in this circumstance is designed to limit thrombus extension following future graft occlusion rather than increasing long-term graft patency. Anticoagulation does not typically extend prosthetic graft patency in the lower extremity, regardless of open or endovascular placement.

FIG 12 • Stent graft. A. This patient has a long SFA occlusion that was relined with Viabahn® stent graft. An aortoiliac arteriogram was performed using contralateral access. B. The left SFA is occluded. There is a patent proximal stump of SFA. C. The point of reconstitution is the above-the-knee popliteal artery. D. The proximal popliteal artery, extending to the knee, is diffusely diseased. E,F. After recanalization and aggressive balloon angioplasty, the artery is reconstructed with Viabahn® stent graft placement. G,H. The

distal end of the graft is fully dilated and without flow limitation in the straight leg and bent knee positions.

PEARLS AND PITFALLS Indications

A complete vascular history is essential to accurately confirm the diagnosis. Objective evidence of ischemia is required to justify intervention and to provide a baseline for future comparison.

Artery puncture

The puncture is planned prior to the procedure. Access site issues are the most common type of complication. A well-performed access will set the procedure up for success.

Specific material

In planning the procedure, check to make sure that all the necessary inventory is available prior to the procedure.

Crossing the lesion

Do not force the wire across the lesion.

Closure

Closure devices can simplify the procedure and allow for more patient comfort and earlier discharge, but accurate CFA access should be confirmed, typically at the outset of the procedure, before therapeutic sheaths are placed.

Follow-up

The patient is evaluated after the procedure at 1 week and 1 month and then 6month intervals after that. We typically obtain some assessment of perfusion (ABI). Duplex mapping may also be performed for surveillance.

POSTOPERATIVE CARE The patient should remain at bedrest for at least 6 hours after the procedure. After use of a closure device, usually 2 hours of bedrest is required. Puncture site management: Obtaining hemostasis is made safer and simpler when the arteriotomy site is carefully managed during the procedure. Ensure the patient is comfortable prior to removing the sheath. Holding pressure: After ipsilateral antegrade puncture, use two hands to hold pressure, one is placed proximal to the inguinal ligament to apply pressure over distal external iliac artery to decrease the pressure flowing through the puncture. The other hand applies pressure over the area of arterial puncture just distal to the inguinal ligament. There are no approved closure devices for antegrade puncture. Following a retrograde puncture, digital pressure is held at the location of arteriotomy, proximal to the skin puncture site. Closure devices: Closure devices are used whenever possible to reduce risk of access site complications and limit patient immobility following the procedure. Newer generations of closure devices are easier to use and are considered a good option for closing the arteriotomy in puncture procedures for 6 Fr and larger. The patient should be encouraged to

Avoid smoking Walk daily Follow best medical treatment Follow-up with the vascular clinic

OUTCOMES Patients with peripheral artery disease (PAD) and critical limb ischemia (CLI) have a shorter life expectancy than the general population. The most effective method of revascularization that returns patients to their premorbid functional state in the shortest period of time, with the least amount of surgical risk, is considered ideal. In this regard, most centers have adopted a percutaneous-first approach to lower extremity revascularization, when intervention is indicated.5 This rubric reserves open surgical reconstruction for patients who fail percutaneous intervention. More recently, controversy has arisen as to how many unsuccessful secondary interventions constitute “failure.” Successful percutaneous revascularization is considered equivalent to traditional standard management strategy —that is, bypass surgery—in providing freedom from major and minor amputation, in patients with severe limb ischemia, up to 2 years following revascularization. To date, the Bypass versus Angioplasty in Severe Ischemia of the Leg (BASIL) trial remains the only randomized prospective trial comparing the success of open surgical bypass versus endovascular therapy for CLI. When life expectancy extends beyond 2 years, bypass patency is superior.6 Although percutaneous transluminal angioplasty (PTA) provides superior limb salvage rate and assisted patency rates than prosthetic bypass, care should be taken to avoid outcomes that limit future bypass options (e.g., injury or occlusion of significant infrageniculate arteries that could serve as future bypass targets). Modern surgical practice should incorporate a full range of postprocedural outcomes, beyond arterial patency alone, in the assessment of procedural success. As such, consideration to postoperative ambulatory status, potential for independent living, wound care requirements, and pain management is essential and comparable to the impact on graft patency on long-term patient satisfaction and quality of life.7 A comparison of self-expandable stents versus femoral-popliteal above-the-knee bypass had been published by Kedora et al., reporting similar limb salvage, with comparable primary (73.5% vs. 74.2%) and secondary patency rates (83.9% vs. 83.7%) at 1 year with both techniques.8 Others studies reported that despite the reduced primary patency, limb salvage rates remain comparable to surgical bypass and range from 74% at 5 years to 84.7% at 8 years.9 Lower limb revascularization of diabetic patients affected by intermittent claudication, in addition to improved walking performance, is associated with a reduction in the incidence of future major cardiovascular events when accompanied by increased physical exercise and improved glucose management and weight control.10

FIG 13 • Complications. Hematoma is the more common access site complication and most common complication of endovascular procedures.

COMPLICATIONS Artery puncture: hematoma, occlusion, dissection, pseudoaneurysm, arteriovenous fistula (FIG 13) Failure of recanalization: intimal dissection, branch occlusion, thrombosis, embolization, vessel rupture, remote hemorrhage Stent/stent graft complications: stent embolization, stent will not expand lesion, stent kink, stent thrombosis Infection

REFERENCES P.278 1. Hirsch AT, Haskal ZJ, Hertzer NR, et al. ACC/AHA 2005 guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic): executive summary a collaborative report from the American Association for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (writing committee to develop guidelines for the management of patients with peripheral arterial disease) endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation; National Heart, Lung, and Blood

Institute; Society for Vascular Nursing; TransAtlantic Inter-Society Consensus; and Vascular Disease Foundation. J Am Coll Cardiol. 2006;47:1239-1312. 2. Faglia E, Dalla Paola L, Clerici G, et al. Peripheral angio-plasty as the first-choice revascularization procedure in diabetic patients with critical limb ischemia: prospective study of 993 consecutive patients hospitalized and followed between 1999 and 2003. Eur J Vasc Endovasc Surg. 2005;29:620-627. 3. Norgren L, Hiatt WR, Dormandy JA, et al. Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II). J Vasc Surg. 2007;45(suppl S):S5-S67. 4. Issack PS, Cunningham ME, Pumberger M, et al. Degenerative lumbar spinal stenosis: evaluation and management. J Am Acad Orthop Surg. 2012;20(8):527-535. 5. Giugliano G, Perrino C, Schiano V, et al. Endovascular treatment of lower extremity arteries is associated with an improved outcome in diabetic patients affected by intermittent claudication. BMC Surg. 2012;12(suppl 1):S19. 6. Nice C, Timmons G, Bartholemew P, et al. Retrograde vs. antegrade puncture for infra-inguinal angioplasty. Cardiovasc Intervent Radiol . 2003;26:370-374. 7. Adam DJ, Beard JD, Cleveland T. Bypass versus angioplasty in severe ischaemia of the leg (BASIL): multicentre, randomised controlled trial. Lancet. 2005;366:1925-1934. 8. Kedora J, Hohmann S, Garrett W, et al. Randomized comparison of percutaneous Viabahn stent grafts vs. prosthetic femoral-popliteal bypass in the treatment of superficial femoral arterial occlusive disease. J Vasc Surg. 2007;45:10-16. 9. Houbballah R, Raux M, LaMuraglia G. Trans-Atlantic debate: lower extremity bypass versus endovascular therapy for young patients with symptomatic peripheral arterial disease. Part two: against the motion. Endovascular therapy is the preferred treatment for patients 20 mmHg) Severe pulmonary hypertension (mean >45 mmHg) Uncontrolled systemic infection or sepsis Unrelieved biliary obstruction Severe tricuspid regurgitation

Relative contraindications

Uncorrectable hepatic encephalopathy Hypervascular liver tumors Portal vein thrombosis Thrombocytopenia of >20,000/cm3 Uncorrectable severe coagulopathy Moderate pulmonary hypertension Complete hepatic vein obstruction

RA, right atrial.

SURGICAL MANAGEMENT Preoperative Planning Risks and benefits of TIPS placement are thoroughly discussed with the patient and family, and informed consent is obtained in the clinic setting. For emergent procedures, the family should be made aware of the morbidity, mortality, and risk of encephalopathy associated with the procedure. Laboratory data and all previous imaging studies should be reviewed to access the extent of liver, renal, and cardiac disease present; to document patency of the portal venous system; and to identify altered anatomy from prior surgeries. Preexisting thrombocytopenia and coagulopathy should be corrected. Blood products should be made available at the blood bank. Patients with active upper GI variceal bleeding should have Blakemore tubes placed for balloon tamponade of varices before transfer to interventional radiology. TIPS can be performed while the esophageal and gastric

balloons are inflated. However, the authors recommend deflation of balloons during post-TIPS placement splenoportogram to assess variceal filling and the need for embolization of varices. Thoracentesis and paracentesis followed by recommended albumin infusion is performed the evening prior to the procedure in elective cases. Preprocedural prophylactic broad-spectrum antibiotics are recommended.

Positioning Patient is placed supine on the angiographic table. Preliminary ultrasound examination of the internal and external jugular veins should be performed bilaterally. Following the initiation of conscious sedation or induction of general anesthesia, the planned jugular venous access site is prepped and draped in sterile fashion. Prepping the right upper quadrant (RUQ) and lower abdomen is recommended if paracentesis or transhepatic portal vein access for guidance is anticipated. Paracentesis or thoracentesis should be performed first if there is significant ascites or hydrothorax. Significant ascites reduces fluoroscopic visibility during the procedure and at the same time increases the radiation dose to the patient. Displacement of the liver due to hydrothorax or massive ascites may also result in unfavorable anatomy for portal vein access. An arterial line for continuous pressure monitoring during the procedure is indicated following large volume paracentesis in patients with active GI bleeding or hemodynamic instability.

VENOUS ACCESS TIPS is most commonly performed through right internal jugular vein access. Using standard Seldinger technique, access to the right internal jugular vein is obtained with ultrasound guidance. Over a guidewire, the access is dilated and a 10-Fr dedicated vascular sheath is placed into the inferior vena cava (IVC). Some practitioners prefer the use of the left internal jugular vein, as it may provide more stable access to the right hepatic vein. Alternatively, the right and left external jugular veins can be used. In cases of superior vena cava (SVC) obstruction, right and left common femoral venous access can be used for recanalization of the SVC to facilitate more standard venous access from above. Common femoral access can also be used directly for TIPS creation in extreme situations. Care is taken with guidewires, dilators, and sheaths to prevent cardiac dysrhythmias and right atrial perforation while crossing the right atrium. Right atrial and IVC pressures are not routinely obtained unless there is a clinical reason such as history of cardiac or pulmonary disease.

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HEPATIC VEIN SELECTION Selection of an appropriate vein of suitable diameter is important. TIPS creation through the right hepatic vein is most common. A standard nonglide, 5-Fr appropriately shaped catheter (based on prior imaging) is then advanced through the sheath into the mid-IVC. As the catheter is withdrawn, the hepatic vein is cannulated. When the right hepatic vein is considered not suitable due to smaller caliber or other anatomic reason,

TIPS can be performed through the middle or even left hepatic veins. It can be difficult to distinguish between the right and middle hepatic veins (MHVs), but it is important to do so. When a wedged hepatic venogram is performed in a steep right anterior oblique (RAO) projection (see Visualization of the Portal Venous System), the right hepatic vein will be posterior and the MHV will be anterior to the right branch of portal vein (FIG 1).

FIG 1 • Relationship of hepatic and portal veins. A. In the AP projection, the right hepatic vein (white arrow) with catheter in it and the MHV (black arrow) are superimposed and are difficult to distinguish. Note the right portal vein (asterisk). B. Steep RAO view shows the right hepatic vein (white arrow) posterior to the right portal vein (asterisk) and the MHV (black arrow) anterior to the right portal vein.

VISUALIZATION OF THE PORTAL VENOUS SYSTEM Indirect visualization of the intrahepatic and extrahepatic portal veins during the TIPS procedure can dramatically decrease procedure time. This can be done in multiple ways. Most commonly, wedged portography using contrast or carbon dioxide (CO2) gas is performed (FIG 2A). CO2 gas is an excellent agent for imaging of the hepatic veins, portal veins, and varices because CO2 can easily flow through the venules and sinusoids due to its low viscosity. CO2 is the contrast agent of choice for wedged hepatic venography and in patients with associated renal impairment. However, use of CO2 is contraindicated in patients with right-to-left intracardiac shunting and should be used with caution in patients with hepatopulmonary syndrome. The right hepatic vein catheter is wedged into a central hepatic venule. Wedge hepatic venogram and indirect portogram is then performed with injection of CO2 gas or contrast. CO2 or contrast will flow through the sinusoids to the portal side resulting in filling of the main portal vein and its branches. Peripheral wedging should be avoided to prevent extravasation and even capsular perforation. Imaging

should be performed in both anteroposterior (AP) and steep RAO projections to properly assess the anatomic relation of the hepatic vein and the right branch of the portal vein (FIG 1). Similarly, the intrahepatic portal branches can also be visualized using an occlusion balloon catheter. In this method, the 5-Fr catheter is exchanged over a guidewire for an occlusion balloon catheter. The balloon catheter is inflated in a branch of the hepatic vein and not wedged. The balloon is inflated to obstruct venous outflow from the segment. The injection pressure of CO2 is dissipated in a larger segment of liver minimizing complications and with better filling of the portal branches and the main portal vein. P.324 Occasionally, wedge portography may fail to visualize portal vein especially in patients with venoocclusive disease and intrahepatic portal vein branch thrombosis. When indirect visualization of the portal vein is unsuccessful, direct visualization can be attempted (see “The Difficult Transjugular Intrahepatic Portosystemic Shunt ”). Under ultrasound guidance, a 22-gauge needle can be inserted percutaneously into the intrahepatic portal venous system for injection of contrast or CO2. This method will require embolization of the parenchyma traversed during portal vein access at the end of the procedure with Gelfoam or coils to ensure hemostasis. Other methods include percutaneous cannulation of a paraumbilical vein or trans-splenic access to the portal vein, both of which also require embolization of the access tract at the conclusion of the procedure.

FIG 2 • Standard TIPS procedure performed for ascites and hepatic hydrothorax in a 65-yearold female with cirrhosis and portal hypertension. A. Digital subtraction angiography with injection of CO2 through a catheter wedged in the liver parenchyma (white arrow) through the right hepatic vein shows excellent visualization of the portal bifurcation (asterisk) and the right and left portal vein branches. B. Rösch-Uchida modification of the original Colapinto needle (Courtesy of Cook Medical, Bloomington, IN). Flexible small trocar needle-catheter combination (yellow arrow) is passed through a directable cannula (black arrow), which has been inserted through a sheath (white arrow). C. The trocar needle-catheter combination (yellow arrow) is advanced into the right portal vein (asterisk) following anteromedial rotation of the directable cannula (black arrow), which has been advanced through a sheath (white arrow). D. Direct splenoportogram with multi-side-hole marking catheter (white arrows) advanced into the portal vein through newly created TIPS tract. (continued)

FIG 2 • (continued) E. Predilation of the TIPS tract with 6- to 8-mm balloon. F. Diagram depicting Gore Viatorr TIPS stent graft demonstrating uncovered portion in the portal vein, gold band at the portal vein entry point, and covered portion within the parenchymal tract and hepatic vein (courtesy of W.L. Gore and Associates, Newark, DE). G. Final portogram showing flow through the TIPS. Note the gold band (white arrow) marking the portal vein access point. H. Embolization of esophageal varix through left gastric vein with coils and alcohol.

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PORTAL VEIN ACCESS A number of commercially available device sets are available for TIPS placement. The most important component of the set is a directional needle with a 30-degree angulated tip and an external marker to show the direction of the tip of the needle developed by Colapinto. Several modifications have been made to this original set, and the commonly used modified set is the Rösch-Uchida set (Cook Medical, Bloomington, IN) and is shown in FIG 2B. This set is designed to be more flexible with a needle tip of

smaller caliber to minimize trauma to liver. The original Colapinto needle (Cook Medical, Bloomington, IN) is modified to an angulated blunt end cannula covered with a sheath and is used to direct a smaller Rösch-Uchida trocar needle-catheter combination for portal vein access. The Colapinto cannula is advanced through the sheath and into the right hepatic vein over a guidewire. The outer sheath and directable cannula are slowly retracted to within 2 cm from the IVC while rotating the tip in the direction of portal vein. The cannula is rotated anteromedially from the right hepatic vein, aiming for the right portal vein as seen on portography (typically seen at the level of the 11th rib approximately 0.5 to 1.5 vertebral body widths from the P.326 spine). The trocar needle-catheter combination is then advanced through the cannula and into the expected location of the right portal vein. The depth of the pass is most commonly 5 cm or less. After removal of the trocar, aspiration of the catheter is performed as it is gradually withdrawn back toward the right hepatic vein. When blood is aspirated, contrast is injected to confirm portal vein access and to assess the suitability of the accessed portal branch for TIPS creation (FIG 2C). Access into the right branch of the portal vein within 2 to 3 cm from the portal vein bifurcation is desired. The portal vein bifurcation is extrahepatic in up to 50% of patients and puncture in this area may lead to exsanguination. Punctures that are too peripheral in the right portal vein are also not optimal because they result in turbulent flow in the TIPS from undesirable angulation. The right branch of the portal vein is posterior in relation to the MHV, necessitating posterior rotation of the cannula for portal vein access. MHV to left portal vein access may need anteromedial rotation of the cannula. It is extremely important to assess the spatial relationship of the chosen hepatic vein and the portal anatomy visualized on portogram to guide the needle pass. Following confirmation of proper access into the portal venous system, a hydrophilic guidewire is advanced into the superior mesenteric or splenic vein. The catheter is exchanged for a multi-side-hole marking catheter over the guidewire (FIG 2D). The 10-Fr sheath is then withdrawn to the right atrium. Dual pressure measurements are obtained in the portal venous system and the right atrium. The difference between the measurements is the portosystemic pressure gradient. A portosystemic gradient (PSG) of 5 to 7 mm is normal and a PSG of greater than 12 mmHg is abnormal. Note that the measured PSG could be lower in the setting of partial portal decompression from extensive portosystemic collaterals such as spontaneous splenorenal shunt. PSGs are also low when the right atrial pressure is transiently elevated from resuscitative measures with intravenous (IV) fluids and blood products, but the absolute portal pressure may remain high from portal hypertension. Direct splenoportography is then performed in AP and oblique projections with iodinated contrast to delineate the portal anatomy, evaluate the presence of competitive shunts and varices as well as to determine the hepatic parenchymal tract length (FIG 2D). In cases of hepatofugal flow, additional venography is performed through the sheath placed within the parenchymal tract to get an accurate measurement of tract length. If the IVC/hepatic vein confluence cannot be clearly visualized during portography, direct contrast injection in that region should be performed to localize the hepatocaval junction for accurate measurement of tract length.

DILATION OF THE TRACT A 180-cm long Amplatz Super Stiff guidewire (Boston Scientific, Natick, MA) is then advanced into the splenic vein and the marker pigtail catheter is removed. The 10-Fr sheath dilator is replaced into the sheath and both the sheath and dilator are advanced over the stiff wire and into the portal vein. When the liver is sclerotic and hard, some operators prefer to predilate the hepatic parenchymal tract with a 6- to 8mm balloon to facilitate advancement of the sheath through the parenchymal tract (FIG 2E).

STENT SELECTION Historically, TIPS was performed with no stent placement within the hepatic parenchymal tract. Tracts were created using only balloon dilation, but patency rates were poor.4 With the development of bare metal stents, long-term patency rates improved to the point that TIPS could be considered a viable alternative to surgical portal decompression. Patency rates improved further with the introduction of polytetrafluoroethylene (PTFE)-covered stent grafts. The most commonly used stent for TIPS placement is the Gore Viatorr PTFE-covered stent graft. The stent is covered with PTFE graft material except for the caudal most 2 cm. The junction between the PTFE covered portion and the bare metal portion is marked with a gold band. The bare stent portion should be placed within the portal vein to allow uninterrupted flow through the interstices and the covered portion is meant to extend through the parenchymal tract and back to the hepatic vein/IVC confluence (FIG 2F). The graft material limits the permeability of bile and mucin into the tract and also eliminates intrastent tissue growth, leading to improved patency rates.5 There is still a role for placement of self-expanding bare metal stents, particularly in patients in whom early transplant is expected, when there is single hepatic venous outflow, or when there is concomitant spontaneous bacterial peritonitis. Even though TIPS were created with balloon expandable bare metal stents in the past, their role is currently limited to pediatric TIPS creation to preserve the ability to increase shunt diameter with the growth of the child.6 They can also be used to eliminate kinks during TIPS revision. P.327 Typically, a stent diameter of 10 mm is used for all TIPS indications. The stent length is equal to the distance of the hepatic parenchymal tract plus the distance of the hepatic outflow vein to the IVC confluence. One centimeter is often added to this number to account for the loss of length that occurs when a stent is deployed in a curved tract and to compensate for minimal foreshortening during deployment.

STENT PLACEMENT The Gore Viatorr stent graft is advanced through the sheath and into the portal vein. The sheath is then withdrawn to expose the uncovered distal 2 cm. The sheath and stent graft are then retracted as a unit until the gold band marking the covered portion of the stent graft is at the edge of parenchymal tract. The gold band should be held exactly at the junction of the portal vein with the parenchymal tract with gentle traction until deployment. With the stent graft held in this position, the sheath is retracted to the right atrium and the release cord is pulled. The stent graft is now deployed. Following deployment, the stent graft shows an hourglass constriction within the parenchymal tract. The stent graft is then expanded completely by dilating with a balloon of the same diameter as the deployed stent graft.

In some patients, such as those with preexisting portal vein stenosis or occlusion, it may be necessary to extend the TIPS into the portosplenic confluence, superior mesenteric vein, or splenic vein to allow effective outflow through the TIPS. This should be performed with self-expanding bare metal stents to preserve inflow into the stent from branches. This may complicate liver transplantation and should be discussed with the transplant team. A correctly placed Gore Viatorr stent graft is easily grasped and removed by a transplant surgeon at the time of liver transplant. The multi-side-hole catheter is readvanced into the portal vein in order to calculate the post-TIPS PSG. When bleeding is the indication, the target PSG is less than 12 mmHg. In the setting of ascites or hydrothorax, gradients under 8 mm are recommended by the Society of Interventional Radiology (SIR) and American Association for the Study of Liver Disease guidelines.2 The risk of hepatic encephalopathy increases significantly when the final gradient is below 5 mmHg. It may be difficult to obtain a truly accurate gradient immediately following emergency TIPS procedure due to the hemodynamic shifts and fluid overload from resuscitative efforts. A final portal venogram is then obtained to ensure proper flow into and out of the TIPS (FIG 2G).

ADJUNCT PROCEDURES When TIPS is performed emergently for refractory variceal bleeding, embolization and sclerosis of gastric and esophageal varices with coils, vascular plugs, or liquid embolic agents such as alcohol should be considered (FIG 2H).

THE DIFFICULT TRANSJUGULAR INTRA-HEPATIC PORTOSYSTEMIC SHUNT The left hepatic vein is used for creation of TIPS (FIG 3) in only exceptional circumstances such as when right liver lobe resection is planned in the presence of mild portal hypertension. If no hepatic veins can be accessed (such as in Budd-Chiari syndrome), a direct IVC to portal vein communication can be created through the caudate lobe (direct intrahepatic portocaval shunt [DIPS]). Transplant surgeons should be made aware of the DIPS anatomy as it may alter surgical approaches for future transplantation. If targeting the portal system is proving to be difficult with fluoroscopy alone, access under real-time P.328 transabdominal or intravascular ultrasound guidance can be used. Other methods of portal vein localization for targeting the access point include percutaneous placement of a metallic marker under ultrasound guidance just anterior to the right portal vein or placement of a balloon (FIG 4A) or catheter within the portal vein from direct transhepatic or paraumbilical vein access (FIG 4B-D). Similarly, a snare can be placed via direct transhepatic access and can be targeted in the same manner as a balloon. In special situations, a technique frequently described as “gunsight” can be used to create the TIPS tract. In this method, a second snare inserted from the hepatic venous circulation can provide gunsight targeting whereby a needle can be percutaneously advanced through both snares to create the TIPS (FIG 4E,F). Gunsight is particularly useful when the hepatic and portal veins are at the same level due to asymmetric shrinkage of the liver or in pediatric patients.

FIG 3 • Patient with prophylactic selective TIPS from the left hepatic vein ostium (white arrow) to the left branch of the portal vein (black arrow) prior to resection of the right liver lobe for colorectal metastatic disease.

FIG 4 • Alternative methods of portal vein targeting. A. Targeting a balloon (white arrow) inserted into right portal vein by percutaneous transhepatic approach with TIPS needle (black needle). B. Catheter placed via paraumbilical vein (white arrow) into the splenic vein. C. Splenoportogram demonstrates catheter entering left branch of the portal vein (white arrow). D. Paraumbilical vein catheter repositioned into the right portal vein (white arrow) and used as a target for advancement of TIPS needle (black arrow). E and F. AP and oblique view of a 22-gauge percutaneously placed needle passing through snares in the portal (white arrow) and hepatic veins (black arrow).

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PEARLS AND PITFALLS Patient history and physical exam

▪ There is level 1 evidence for TIPS placement for variceal bleeding and for ascites refractory to medical management. ▪ Altered anatomy from prior surgeries may increase the complexity of TIPS placement.

Imaging and other diagnostic

▪ Preprocedure imaging of the liver to evaluate hepatic and portal venous anatomy, portosystemic collateral pathways, ascites, and intrahepatic tumors

studies

is essential. ▪ MELD score should be calculated for risk stratification.

Preoperative planning

▪ Paracentesis improves ventilation, fluoroscopic visibility, and reduces radiation to the patient and operator. ▪ Gastroesophageal balloon tamponade tubes should be placed in unstable patients with active upper GI variceal hemorrhage.

Positioning

▪ Surgical preparation of RUQ and anterior abdominal wall should be considered for transhepatic access to the portal vein and for draining ascites if needed.

Venous access

▪ Although the right internal jugular vein is most commonly used, TIPS creation is feasible through alternative venous access.

Hepatic vein selection

▪ The right hepatic vein is most commonly used for TIPS creation. ▪ AP and steep RAO projections can help identify the right hepatic vein by noting its spatial relationship with the right portal vein.

Visualization of the portal venous system

▪ CO2 is the contrast agent of choice for wedge hepatic venography. ▪ Anatomic localization of the intrahepatic portal vein for access significantly reduces procedure time.

Portal vein access

▪ Direction of rotation of the Colapinto cannula varies based on hepatic vein selected. ▪ Access within 2 to 3 cm of the portal vein bifurcation is most desirable. ▪ Measurement of PSG is essential prior to TIPS placement.

Dilation of the tract

▪ Balloon dilation of the tract facilitates advancement of the sheath into the portal vein.

Stent selection

▪ The Gore Viatorr endoprosthesis is the desired stent for TIPS creation whenever feasible.

Stent placement

▪ The gold band of the Gore Viatorr must be placed at the junction of the portal vein entry site and the hepatic parenchymal tract. ▪ A post-TIPS PSG of less than 12 should be achieved in all bleeding patients.

Adjunct procedures

▪ In patients with refractory variceal bleeding, embolization of varices should be considered.

The difficult TIPS

▪ When preprocedural imaging and wedged portography depicts unfavorable anatomy, alternative TIPS creation strategies should be considered.

POSTOPERATIVE CARE Following emergency TIPS for active variceal bleeding, patients are admitted to the intensive care unit (ICU) until they are hemodynamically stable. Following elective TIPS, patients are admitted overnight for inpatient observation. Immediate postoperative care for emergent TIPS placement consists of continued resuscitation and hemodynamic monitoring. Shunt placement immediately elevates right atrial (central venous) pressure, increasing cardiac preload, which can lead to heart failure. Variceal bleeding may continue with incomplete reduction of absolute portal pressure secondary to elevated central venous pressures. Steps should be undertaken to reduce right atrial pressure. Patients with continued bleeding should have repeat upper GI endoscopy to rule out nonvariceal source of bleeding. Reevaluation of the TIPS shunt and embolization of residual bleeding varices should be performed for continued variceal bleed. Repeat CBC and coagulation panel should be performed every 4 hours. Urine output is monitored. Serum creatinine level and liver function tests are checked at 12 and 24 hours. Patients are periodically checked for altered mentation. Transient alterations in liver function tests are usually noted immediately following TIPS. Progressive worsening of liver function with encephalopathy is a cause for concern. A liver ultrasound with complete Doppler evaluation of the TIPS shunt is obtained 2 to 3 days following TIPS placement. Lactulose administration can be considered in encephalopathic patients.

OUTCOMES Technical success is greater than 95% in most centers. SIR TIPS quality improvement guidelines recommend thresholds of 95% for technical success and 90% for clinical success.2 Following emergent TIPS for variceal hemorrhage, bleeding control is achieved greater than 90% of patients. Mortality rates range from 27% to 50% following TIPS placement and is related to risk classification scores, hemodynamic instability at the time of placement, and the presence of other comorbidities.7 Mortality rates are significantly higher than P.330 in patients undergoing elective TIPS placement. Rebleeding rates are lower after TIPS shunt placement with adjunctive variceal embolization and sclerosis.8 Following elective TIPS, there is significantly higher survival rate in patients treated for variceal bleeding compared to those treated for ascites (>60 months vs. 29 months).9 TIPS creation is superior to large volume paracentesis with albumin infusion to treat refractory ascites. However, TIPS patients have higher rates of encephalopathy and no definite survival benefit has been shown.10 Early, 3 months and 6 months, mortality rates are significantly higher in patients with MELD scores of 18 or greater who are undergoing elective TIPS placement. (In addition, 6-month survival for patients with MELD scores less than 10 is 100% compared to 25% for patients with scores over 24.10) TIPS created using PTFE-covered stents compared to bare metal stents demonstrate a lower rate of TIPS dysfunction (15% vs. 44%), higher primary patency rate (76% vs. 36%), decreased likelihood of developing encephalopathy (33% vs. 49%), and a lower rate of clinical relapse (10% vs. 29%).7

De novo or worsening encephalopathy may be seen in 20% to 31%. However, most can be managed medically and shunt occlusion is only required in less than 5%.2

COMPLICATIONS Although TIPS is a relatively safe procedure, complications can arise during every step of TIPS placement due to the complexity of the procedure. In addition, early and delayed nonprocedure-related complications are also associated with significant morbidity. Procedure-related complications Procedure-related mortality in published series is 0.6% to 4.3%, but the procedure-related mortality in most major centers is about 1.4%.2 Major procedural complication rate should be no more than 3%. Most procedurerelated complications can be minimized by careful preprocedural evaluation of crosssectional images, proper portal vein localization, having a clear understanding of the procedure, and by the use of meticulous technique. Intraperitoneal hemorrhage, a serious complication associated with procedure-related mortality, can occur due to liver capsule perforation during needle passes or from puncture of the portal vein in an extrahepatic location. Rarely, bleeding occurs from hepatic artery pseudoaneurysm or arteriovenous fistula formation, hepatic artery laceration, IVC perforation, or gallbladder perforation. Additional intervention such as arteriography and embolization may be required to treat extrahepatic source of bleeding and hepatic artery lacerations.11 Other procedure-related complications include jugular access-related hematoma, cardiac arrhythmias during advancement of devices through the right atrium, nontarget organ puncture, and injury to the bile ducts. Periprocedural complications Liver enzyme elevation is noted frequently after shunt placement but is usually transient. Persistent elevation may indicate liver failure from the reduction of blood flow into the liver caused by the TIPS. Persistent hyperbilirubinemia has been noted from chronic hemolysis. Infectious complications, such as liver abscess formation and graft infection (endotipsitis), are uncommon (FIG 5). At present, there is no evidence that the use P.331 of prophylactic antibiotics is beneficial before TIPS placement.11 Treatment usually consists of longterm antibiotic therapy coupled with percutaneous abscess drainage as needed. Attempts to reopen the TIPS should not be performed until all signs of infection have resolved. Rapid deterioration of liver function following TIPS, worsening encephalopathy, and elevated blood ammonia is rare. Reduction of shunt caliber and, in extreme cases, closure of TIPS should be considered. Right liver lobe infarction due to obstruction of the right branch of portal vein preventing inflow to or outflow from the right liver lobe is a very rare complication. Reduction in hepatic sinusoidal perfusion due to reduced compensatory hepatic artery inflow from any cause can potentially increase the risk of ischemic complications. Delayed complications Hepatic encephalopathy can be caused or worsened by TIPS placement in up to a third of patients undergoing TIPS. Most patients respond to medical management with elimination of precipitating factors, dietary modification, administration of nonabsorbable disaccharides such as lactulose, and

antibiotics. Reduction in shunt diameter or even occlusion of TIPS is needed in very few patients. Recurrent variceal bleeding or recurrence of ascites may suggest TIPS dysfunction (see TIPS Dysfunction). Rarely, when a TIPS shunt is ineffective in adequately reducing the PSG, a second TIPS (parallel TIPS) (FIG 6) placement should be considered to reduce the PSG further. Radiation injury to the skin can occur with prolonged procedural times. The risk of radiation injury can be significantly reduced with periodic changes in angulation of the image intensifier.

FIG 5 • TIPS complications. A. Technically difficult TIPS performed for variceal bleed. Hepatic arteriogram performed for hemobilia shows laceration (white arrow) and pseudoaneurysm (black arrow) of the left branch of the hepatic artery. B. Liver abscesses (asterisks) secondary to infected TIPS (white arrow) stent (endotipsitis).

FIG 6 • Parallel TIPS from the right hepatic vein (black arrow) placed secondary to persistently elevated PSG, following original 8-mm TIPS from the MHV (white arrow).

TRANSJUGULAR INTRAHEPATIC PORTOSYSTEMIC SHUNT DYSFUNCTION Recurrent portal hypertension with stenosis or occlusion of the shunt is a significant drawback of TIPS creation. Better primary and secondary patency rates are now achieved with the introduction of PTFE-covered stents. Early TIPS dysfunction is seen secondary to technical and biologic factors resulting in occlusion or stenosis of the TIPS. The technical causes include inadequate coverage, stent shortening, and stent migration. The biologic factors include communication of bile ducts with the shunt tract resulting in stent thrombosis and parenchymal tract stenosis from intrastent tissue growth from cellular hyperplasia (FIG 7A). PTFEcovered grafts have mostly eliminated the biologic factors.12 Inadequate extension of the stent to the junction of the IVC and hepatic vein confluence leaves a segment of

the hepatic vein uncovered. This predisposes the hepatic venous end of the TIPS to stenosis from intimal hyperplasia. Extension of the stent to the IVC is an important determinant of shunt patency (FIG 7B,C). Dysfunction may also result from poor portal venous inflow into the shunt because of competitive shunts or kinking of the TIPS stent. Secondary interventions are usually successful in the salvage of dysfunctional TIPS. Completely occluded TIPS (FIG 7D) can be salvaged with mechanical or pharmacomechanical thrombolysis and relining with a stent to the hepatocaval junction as needed. Stenosis of the hepatic venous end, and occasionally, the portal venous end of the TIPS is treated with repeat balloon dilation and placement of a new stent to cover the lesion if needed. Inflow-related dysfunction from competitive shunts is treated by embolization and sclerosis of the competitive shunts to redirect the blood flow toward the liver. Care should be taken to prevent infolding of a Gore Viatorr PTFE-covered stent graft when the stent graft is placed inside a preexisting Wallstent (Boston Scientific, Natick, MA) during revision by adequately dilating with high-pressure balloons to the appropriate diameter.

FOLLOW-UP OF TIPS TRANSJUGULAR INTRAHEPATIC PORTOSYSTEMIC SHUNTS Periodic screening of TIPS with Doppler ultrasound is an effective noninvasive method to recognize TIPS dysfunction early. Although there is no consensus about the timing of TIPS screening, Doppler ultrasound at 1 month, 3 months, 6 months, 1 year, and then biannual is performed at many major centers. Ultrasound should also be performed if there is a return of pre-TIPS symptoms. The findings of TIPS dysfunction on ultrasound examination are listed in Table 2.13 Clinical or Doppler ultrasound evidence of TIPS dysfunction should be followed by catheterization of the TIPS with direct P.332 portography and pressure measurements. Dysfunctional shunts can be revised on an outpatient basis with balloon dilation of stenosis, extension of the stent, or relining of the stent as needed based on the portogram and pullback pressures to restore acceptable PSGs.

FIG 7 • TIPS dysfunction. A. Stenosis (white arrow) of midaspect of TIPS created with a self-expanding bare metal stent (Wallstent, Boston Scientific, Natick, MA) due to leakage of bile and mucin into the tract. B. The hepatic venous end of this Wallstent (Boston Scientific, Natick, MA) TIPS is “T-barred” into the superior aspect of the right hepatic vein (white arrow) causing TIPS dysfunction. C. Extension of the TIPS with another Wallstent (Boston Scientific, Natick, MA) to the IVC/hepatic vein confluence (white arrow) relieves this pseudoobstruction. D. Portogram shows occluded TIPS shunt (white arrow) with extension of thrombus (black arrow) into the splenomesenteric confluence and recurrence of varices (yellow arrow).

Table 2: Ultrasound Criteria Suggesting Shunt Dysfunction Absent flow within the TIPS High-peak shunt velocities (>190 cm/s) Low-peak shunt velocities (