Endovascular skills : guidewire and catheter skills for endovascular surgery [4 ed.] 9781482217377, 1482217376

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Endovascular Skills Guidewire and Catheter Skills for Endovascular Surgery Fourth Edition

Endovascular Skills Guidewire and Catheter Skills for Endovascular Surgery Fourth Edition

Peter A. Schneider Division of Vascular and Endovascular Surgery University of California, San Francisco San Francisco, California, USA

CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2020 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed on acid-free paper International Standard Book Number-13: 978-1-4822-1737-7 (Hardback) This book contains information obtained from authentic and highly regarded sources. While all reasonable efforts have been made to publish reliable data and information, neither the author[s] nor the publisher can accept any legal responsibility or liability for any errors or omissions that may be made. The publishers wish to make clear that any views or opinions expressed in this book by individual editors, authors or contributors are personal to them and do not necessarily reflect the views/ opinions of the publishers. The information or guidance contained in this book is intended for use by medical, scientific or health-care professionals and is provided strictly as a supplement to the medical or other professional’s own judgment, their knowledge of the patient’s medical history, relevant manufacturer’s instructions and the appropriate best practice guidelines. Because of the rapid advances in medical science, any information or advice on dosages, procedures or diagnoses should be independently verified. The reader is strongly urged to consult the relevant national drug formulary and the drug companies’ and device or material manufacturers’ printed instructions, and their websites, before administering or utilising any of the drugs, devices or materials mentioned in this book. This book does not indicate whether a particular treatment is appropriate or suitable for a particular individual. Ultimately it is the sole responsibility of the medical professional to make his or her own professional judgments, so as to advise and treat patients appropriately. The authors and publishers have also attempted to trace the copyright holders of all material reproduced in this publication and apologise to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilised in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www. copyright. com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-7508400. CCC is a not-for- profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

Contents

Preface to the Fourth Edition

xiii

Abbreviations xv Part I  CATHETER AND GUIDEWIRE SKILLS 1

2

3

1

Case preparation 3 Endovascular skills in practice 3 Reinvention of vascular care 3 Setting yourself up for success 3 Sizing up the case 4 Prior to the puncture 4 Working environment 4 Equipment 5 Facilities and room setup 5 How pretreatment history and physical examination help to plan therapy 6 Pretreatment imaging 6 Safe and strategic vascular access 7 Overview of percutaneous access 7 Choosing your approach 8 Femoral anatomy for arterial access 9 Puncture guidance with ultrasound 10 Micropuncture technique 12 Percutaneous retrograde puncture of the femoral artery 13 Percutaneous antegrade puncture of the femoral artery 17 Percutaneous puncture of a pulseless femoral artery 19 Proximal access 21 Percutaneous puncture of the brachial artery 21 Alternative access to the lower extremity: Superficial femoral, popliteal, tibial, and pedal arteries 23 Percutaneous puncture of bypass grafts 23 Puncture site complications 24 Summary of puncture site options and closure strategy 24 Sheath access 27 Introduction 27 Basic access site step-by-step 27 Initial maneuvers to secure the access 28 v

vi Contents

4

5

6

7

8

How do you place a sheath? 28 When is a dilator needed? 30 Basic sizing issues 32 When to use fluoroscopy 32 About access sheaths 33 How do you decide when to place a larger access sheath? 33 When to abandon an access 33 Access in a hostile groin 34 Guidewire skills 35 Introduction 35 Mastering guidewires 35 What makes guidewires different from each other 36 Guidewire types in practice 38 When to abandon the chosen guidewire 43 Useful guidewire techniques to start tackling chronic total occlusion 44 Organizing your guidewires 46 Small platform guidewires and monorail systems 47 Development of small platform guidewires and monorail systems 47 How do monorail systems differ from coaxial systems? 47 What are the advantages and disadvantages of monorail systems? 49 Principles for the use of rapid exchange systems 49 Which platform is best for each task? 50 Which platform should you start the case with, and when should you switch from one platform to another? 50 Maneuvers you can undertake with 0.14-inch and 0.18-inch guidewires 51 Handling catheters 53 Introduction to catheters: Exchange, flush, and selective catheters 53 Which angiographic catheter should you use? 53 Catheter head shape determines function 54 Describing catheter behavior 58 Handling catheters 58 Guidewire and catheter passage 63 The goal of the procedure determines the course of the guidewire–catheter apparatus 63 Guidewire and catheter combinations 65 Where does the guidewire naturally want to go? 65 Passing through diseased arteries 66 Negotiating tortuous arteries 67 Remote puncture site 69 How to change the plan if the catheter will not pass and you have tried everything 70 How do you decide if disease encountered on the pathway to treat the target lesion also needs to be treated? 71 Imaging: The key to success 77 Imaging and best therapy are intricately linked 77 Image quality 77 Generating an X-ray image 78 Digital subtraction arteriography 79 Imaging technique for best resolution 80 Road mapping: How it works and when to use it 81 Automated power injector 82 Power injection versus contrast administration by hand 83 Contrast agents 84

Contents vii

9

10

11

How do you know where you are? Radiation safety and occupational health issues Radiographic equipment Radiographic terms Radiation exposure Selective catheterization Many catheter choices but few basic shapes Selective catheterization of the brachiocephalic arteries Selective catheterization of the visceral and renal arteries Selective catheterization of the aortoiliac arteries Selective catheterization of the infrainguinal arteries Selective catheterization of prosthetic bypass grafts Aberrant anatomy to consider Principles of arteriography Arteriography is strategic, not diagnostic The future of arteriography Supplies for arteriography Planning for strategic arteriography Questions to consider before arteriography Evaluation before angiography Deciding where to puncture Catheter placement Contrast administration and image acquisition Arteriography sequences Arteriography of the vascular beds Arteriography of the brachiocephalic arteries Thoracic aortography Arteriography of the visceral and renal arteries Arteriography of the infrarenal arteries Lesion interrogation: Special views Carbon dioxide arteriography Pressure measurement Arteriography of aneurysms Intravascular ultrasound

Part II  ENDOVASCULAR THERAPY 12

13

85 86 86 86 87 89 89 91 98 100 105 109 111 113 113 113 114 114 115 115 116 118 119 120 123 123 126 126 128 134 134 136 136 137

139

Endovascular workshop 141 Where we work determines what we can do 141 Operating room versus special procedures suite versus catheterization laboratory 141 Stationary versus portable imaging systems 142 The ideal vascular workshop 143 Medications for endovascular therapy 145 Sedation and analgesia 145 Local anesthetic 145 Prophylaxis with antibiotics 145 Anticoagulation 145 Heparin alternatives: Direct thrombin inhibitors 146 Antiplatelet agents 146 Thrombolysis 147

viii Contents

14

15

16

17

18

Vasodilators 147 Contrast allergies 147 Practical advice for intraoperative problems 147 Access for endovascular therapy 149 Make access as simple as possible 149 Create a platform from which to work 150 Sizing considerations 150 What fits into what? 153 General principles of sheath placement during therapy 153 When to avoid using your initial access site for therapy 155 When do you use a guiding sheath versus a guiding catheter? 155 How do you know if the sheath is following the exchange wire? 158 Uses for upper extremity access 159 Sheath placement in remote branch arteries 159 Setting up the therapeutic maneuver: Crossing lesions 163 Introduction 163 Three types of lesions 163 Need for support and directionality 164 Crossing stenoses 164 Crossing challenging lesions 171 Arteriography of occluded arteries 171 Crossing occlusions 171 Tools for crossing occlusions  174 Subintimal angioplasty 176 Crossing occlusions in various vascular beds 178 When to approach from the other direction: Retrograde access 184 Crossing calcified lesions 186 Crossing really long lesions 186 What to do after the wire is across 187 Anatomic manipulations can assist in guidewire or device passage 188 Balloon angioplasty: Minimally invasive autologous revascularization 191 Balloon dilation causes dissection 191 About balloon catheters 192 The angioplasty procedure 193 Balloon selection 193 When to use a monorail system 195 Supplies for percutaneous balloon angioplasty 195 Sheath selection and placement 196 Balloon preparation and placement 197 Heparin administration during intervention 197 Balloon inflation 198 Balloon removal and completion arteriography 201 More about balloon angioplasty: Keeping out of trouble 205 Keeping out of trouble is simpler than getting out of trouble 205 What is the strategy for managing multiple lesions? 205 Which lesions should be predilated? 207 Which lesions are most likely to embolize? 208 What about postangioplasty dissection? 208 When to use kissing balloons 210 Pain during balloon angioplasty 210 What about spasm? 211

Contents ix

19

20

Preventing puncture site thrombosis 212 Balloon angioplasty troubleshooting 213 Technique: Solving angioplasty problems 215 Management of arterial rupture 217 Management of embolization 218 Management of acute occlusion 219 Technical aspects of balloon angioplasty in different vascular beds 219 Assessing the acute results of balloon angioplasty 221 Stents, covered stents, stent–grafts 223 Impact of stents 223 Stent choices 223 Covered stents 225 Indications for stents: Primary or selective stent placement 226 Which lesions should be stented? 227 Residual stenosis after angioplasty 229 Placement technique for balloon-expandable stents 230 Placement technique for self-expanding stents 235 Placement technique for covered stents 237 Which stent for which lesion? 238 How to select the best stent for the job 241 Tricks of the trade 242 Acute complications of stent placement 252 Chronic complications of stent placement 253 Other devices and how to use them 255 Microcatheters 255 Re-entry catheters 256 Chronic total occlusion catheters and crossing catheters 257 Atherectomy 258 Laser 260 Drug-coated balloons and drug-eluting stents 261 Cutting, scoring, and cryoplasty balloons 262 Peripheral stent–grafts 265 Thrombectomy and thrombolysis 266 Distal embolic filters 269

Part III  THERAPY IN SPECIFIC VASCULAR BEDS 21

273

Brachiocephalic interventions 275 Introduction 275 Arch assessment 275 Innominate and common carotid artery 275 Assessment of arch branch lesions 276 Principal techniques 277 Transfemoral approach to the common carotid artery 279 Carotid bifurcation stent placement 281 Open cell, closed cell, and mesh covered carotid stents 286 Distal and proximal protection devices for transfemoral carotid stenting 287 Transcervical approach to carotid stenting 288 Retrograde approach to the common carotid artery 292 The subclavian and axillary arteries 292

x Contents

22

23

24

25

26

27

28

Visceral and renal artery interventions 297 Approach to the visceral arteries 297 Celiac and superior mesenteric artery angioplasty and stenting 297 Renal angioplasty and stenting 302 The infrarenal aorta, aortic bifurcation, and iliac arteries: Advice about balloon angioplasty and stent placement 311 Introduction 311 Aorta 311 Aortic bifurcation 318 Iliac artery 321 Ipsilateral retrograde approach to the iliac artery 321 Contralateral approach to the iliac artery 323 Self-expanding versus balloon-expandable stents for the aortoiliac segment 326 Use of covered stents 326 Access related issues 327 The infrainguinal arteries: Advice about balloon angioplasty and stent placement 329 Introduction 329 Superficial femoral and popliteal arteries 329 Ipsilateral antegrade approach to the superficial femoral and popliteal arteries 330 Up-and-over approach to the superficial femoral and popliteal arteries 334 Access related issues: Difficult up-and-over approach to the superficial femoral and popliteal arteries 337 Tibial artery occlusive disease: Angioplasty and stenting 341 Complex lower extremity revascularization 345 Aortoiliac occlusive disease 345 Femoral–popliteal occlusive disease 353 Tibial artery occlusive disease 365 Angiosomes of the lower leg and foot 367 Salvage of previous reconstructions 373 Introduction 373 Previous endovascular reconstruction 373 Managing occluded stents 374 Infrainguinal bypass graft 375 Extra-anatomic bypasses: Axillofemoral and femoral–femoral 378 Reconstructions for aortoiliac disease: Aortofemoral, iliofemoral, and aortoiliac bypasses 378 Hybrid procedures 381 Principles of hybrid procedures 381 Technical points for performing hybrid procedures 381 Iliac stent and femoral endarterectomy 387 Femoral endarterectomy plus distal intervention 389 Technical aspects of treating aortic aneurysms 391 Introduction 391 Imaging 391 Open access or percutaneous access of femoral arteries 392 Percutaneous large bore access using the pre-close technique 392 Closure of large bore access 394 Managing bad iliac arteries 394 Conduits 398 Endograft placement 401 Cannulation of the contralateral gate 403 Balloon angioplasty after endograft placement 405

Contents xi

29

30

Postplacement stenting of iliac arteries 406 Management of a difficult aortic neck 407 Endovascular graft treatment of a ruptured abdominal aortic aneurysm 411 Hybrid procedures associated with aortic disease: Arch debranching 413 Management of endoleaks after endovascular abdominal aortic aneurysm repair 414 Coiling of peripheral aneurysms 419 Coils 419 Vessel occluders 423 Endovascular management of a popliteal aneurysm 424 Puncture site management 427 Obtaining hemostasis 427 Holding pressure 427 Timing the sheath removal 429 Closure devices 429 Managing puncture site complications 432

Selected reading

433

Appendix: Trade/registered/generic names plus current manufacturers

437

Index 441

Preface to the Fourth Edition

The goal of Endovascular Skills: Guidewire and Catheter Skills for Endovascular Surgery has always been to provide a “step-by-step” approach to techniques and procedures that comprise one of the most exciting and rapidly developing specialties in medicine today: minimally invasive management of vascular disease. The text is meant to capture what might sound like a conversation between two clinicians about a particular patient or during the course of a procedure. Endovascular technique has gone from a novelty to a mainstay of vascular care, and this edition of Endovascular Skills has been revised and expanded to reflect these changes. This book serves as a “how-to” guide for endovascular intervention and aims to assist clinicians in the development and refinement of skills that are now essential to vascular practice. Since Endovascular Skills was first published in the mid-1990s, endovascular intervention has gone through a tremendous phase of development. Significant advances have been made in reopening and relining vessels in every vascular bed. More extensive patterns of vascular disease are being treated, many of which would have required open surgery in the past. The endovascular approach has become more broadly accepted by patients, medical professionals, scientists, engineers, and the public at large. The technical skills and the device innovations that make endovascular practice possible have advanced and developed over the past few years, providing new treatment options that are safer and better tolerated. These skills and devices will likely continue to develop for the foreseeable future. Simultaneous growth in the public health challenge of an enlarging patient population at risk for vascular disease will likely prompt wider adoption and even more new applications. The skills to perform endovascular techniques are based on several principles, which are outlined in Endovascular Skills. The book introduces readers to strategy, vascular access, guidewire–catheter handling, and arteriography in a multitude of vascular beds. The knowledge base builds as the text progresses in much the same manner that the skill of the professional builds as experience is gained by performing more complex cases and managing complicated patterns of disease. The chapters progress to all aspects of endovascular therapy, including sheath access, balloon angioplasty, stents, and other treatment modalities. These sections have been revised to incorporate the most contemporary practices of advanced imaging and endovascular treatment techniques, including use of 0.014-inch guidewires and small caliber platforms, atherectomy, stent–grafts, subintimal angioplasty, carotid bifurcation stenting, hybrid procedures, techniques associated with endovascular aneurysm treatment, and many others. The possession of endovascular skills by clinicians dedicated to the management of vascular disease is one of the keys to advancing patient care in this area. The Fourth Edition of Endovascular Skills aims to assist in that challenging and rewarding endeavor. Peter A. Schneider

xiii

Abbreviations

ACT activated clotting time AP anteroposterior (projection) atm atmosphere of pressure CAS carotid artery stent CO2 carbon dioxide CT computed tomography CTA computed tomography angiography CTO chronic total occlusion DAPT dual antiplatelet therapy DCB drug-coated balloon DES drug-eluting stent DOAC direct oral anticoagulant DSA digital subtraction arteriography FDA Food and Drugs Administration ID inside diameter IM intramuscularly IMA inferior mesenteric artery INR international normalized ratio IV intravenously

IVUS intravascular ultrasound LAO left anterior oblique (projection) MRA magnetic resonance angiography NPO nothing per oral OCT optical coherence tomography OD outside diameter OR operating room PET polyethylene terephthalate PO per os POBA plain old balloon angioplasty psi pounds per square inch PTA percutaneous transluminal angioplasty PTFE polytetrafluoroethylene RAO right anterior oblique (projection) RDC renal double curve SFA superficial femoral artery SMA superior mesenteric artery TCAR transcarotid artery stenting tPA tissue plasminogen activator

xv

I

Part     Catheter and guidewire skills

1 2 3 4 5 6 7 8 9 10 11

Case preparation 3 Safe and strategic vascular access 7 Sheath access 27 Guidewire skills 35 Small platform guidewires and monorail systems 47 Handling catheters 53 Guidewire and catheter passage 63 Imaging: The key to success 77 Selective catheterization 89 Principles of arteriography 113 Arteriography of the vascular beds 123

1 Case preparation ENDOVASCULAR SKILLS IN PRACTICE Endovascular skills are an integral part of v­ascular patient care and will continue to be for the foreseeable future. As the scope of catheterbased treatment broadens, the ability to manage more complex lesions with these techniques will continue to increase and, hopefully, drive better overall results of care. The development of ­guidewire–catheter skills is not an easily definable goal, but is a dynamic process. As the array of possibilities in the endovascular field has blossomed, the necessary skills included under the heading of guidewire–catheter skills have likewise increased substantially. On the basic level, guidewires and catheters are the universal instruments of success in endovascular work. A more advanced approach includes an amazing and expanding myriad of devices passed over the guidewire to help manage vascular disease. Knowledge and facility must be achieved in ­several areas that are not necessarily intuitive, including coordinating fluoroscopy–eye–hand motion, predicting guidewire–lesion interactions, understanding the behavior of various guidewire and catheter combinations, and learning the limits of each technique. These are the basic endovascular skills. Part I of this book ­provides an overview of basic endovascular skills. Part II presents techniques in endovascular therapy that build on the basic skills, such as guiding sheath access, balloon angioplasty, stenting, and how to use these techniques in various vascular beds. Part III covers advanced endovascular techniques and devices in an effort to assist the reader in becoming familiar with rapidly evolving technology.

REINVENTION OF VASCULAR CARE Endovascular concepts are reshaping treatment. The potential for simple, low-morbidity solutions to complex clinical problems is a common goal among vascular specialists. Near-term progress in reconstructive capability is likely to result from advances in endoluminal technique. Guidewires and catheters form the technical and conceptual basis of endovascular intervention and technology, while device and skill development are taking the field to the next level. Endovascular procedures have dramatically changed the spectrum of vascular practice. Iliac angioplasty and stenting have almost completely replaced aortofemoral bypass. Stent–graft repair of abdominal aortic aneurysms has dramatically altered the management paradigm for aneurysmal disease. Although some endovascular procedures are not currently durable enough to offer long-term solutions, such as many of the infrainguinal treatment options, they may still be adequate for patients with multiple comorbidities or limited life expectancy. These techniques also hold hope for becoming more clinically useful as they are refined and patency improves. Our focus is on making vascular treatment safer and more durable, whether it involves medical, endovascular, or open surgical procedures, or a combination of these.

SETTING YOURSELF UP FOR SUCCESS The success of a case depends in part on addressing a few concerns that arise before the procedure commences. Evaluation of the patient and a preprocedure analysis make a difference. Decisions about access and strategy, how compelling the indications 3

4  Case preparation

are for treatment, and the expectations of the patient and family all play important roles. Throughout this book, there is advice about these issues. Chapter 2 details access choices and how to use them. The chapters included in Part III offer a number of ideas about treatment strategy. Chapter 13 discusses where we work and related issues. This chapter deals with some of the logistical issues that everyone faces in performing endovascular surgery.

SIZING UP THE CASE Issues to address with regard to medical management of the patient may be numerous. The ones that occur most frequently are management of diabetes, renal insufficiency (contrast tolerance), and anticoagulation or antiplatelet agents. Each of these must be appropriately balanced based on an estimation of what needs to be done, how long it will take, how extensive it will be, and whether or not it will solve the patient’s problem. In the midst of all this, the patient must be prepared by the physician and staff for the shortest possible hospital stay, maybe only a few hours. Logistical issues around transportation, mobility, and accompany home by a family member must be addressed. In  preparing for the technical part of the case, check old angiograms and procedure notes. Examine the patient and perform a complete vascular examination. Palpate the arteries and assess puncture sites. Obtain and analyze some type of preprocedure noninvasive study to assist with planning.

PRIOR TO THE PUNCTURE Informed consent is best obtained in the office when the patient is afforded time to consider issues and to consult with family. Patients on warfarin or other anticoagulants should be considered on a case-by-case basis. It is usually safe to perform either arteriography or endovascular intervention in patients on antiplatelet therapy as long as there are no other factors that are likely to promote hemorrhage, such as dialysis dependency. It  is usually not necessary to stop antiplatelet agents prior to endovascular intervention. If for some reason the  antiplatelet agent must be stopped, it should be 10 days prior to the procedure. If endovascular intervention is required, warfarin should be stopped approximately 5 days prior to the ­procedure. Patients who require anticoagulation

to be continued, except for a “window” when it is stopped, may often be treated with outpatient enoxaparin sodium to shorten the hospital stay. At the operator’s discretion is whether a prothrombin time should be obtained on the day of the procedure. Patients with renal insufficiency are managed with preoperative hydration with a bicarbonate infusion and mucomyst. Methods of preprocedural evaluation are available that help to limit the contrast required for the study. These are discussed in Chapter 11. A contrast agent that is less toxic to the kidneys (e.g., CO2) should also be considered. Patients with a history of contrast allergy should be treated before the procedure with prednisone and diphenhydramine. This protocol is detailed in Chapter 13.

WORKING ENVIRONMENT Experts understand that top performance is something that does not happen randomly. It develops with preparation. Judgment and technical skills take time, effort, and enthusiasm to develop. The staff that assist you, the equipment available, and the facility where you use those skills can either promote or detract from your ability to guide sick patients through difficult situations. These preparations help to limit the variables and optimize results. Endovascular work is no different. There is a substantial learning curve associated with each procedure. Creating a working environment where high-quality endovascular practice can be carried out is essential. It is imperative to ensure the presence of the proper interventional equipment when performing endovascular interventions. The necessary catheters, guidewires, guiding catheters and sheaths, balloons, and stents must be available. The room must be equipped to adequately monitor the patient. Medications must be available, including anticoagulants, antiplatelet agents, hemodynamic medications as needed, and sedation as required. The staff must be knowledgeable in the inventory of the supplies, devices, and equipment used during interventional procedures. The surgeon must be comfortable with the ability of the staff to assist in performing these procedures. Educating the staff beforehand on the nature of the procedure to be performed, the important points of the case, and the specific assistance that will be necessary are critical to ensuring smooth progression

Facilities and room setup  5

through the case. Adequate monitoring of the patient allows rapid assessment of the patient’s status, thereby allowing intervention for hemodynamic problems early and limiting their impact on the outcome. It  is important that the person performing the intervention is confident that the people assisting can quickly deal with hemodynamic or other problems. Fixed imaging equipment is not mandatory but is best and facilitates performance of endovascular procedures. A room stocked with adequate disposable inventory is desirable. It is helpful to develop a method of arranging the room for different procedures, depending on the proposed access site and the area of intended imaging and target site for treatment.

EQUIPMENT The patient must be monitored during and after the  procedure. Otherwise, the attractive advantages of a less morbid and less invasive procedure may be negated by some unfortunate complicating event. It is imperative to have monitoring equipment in both the procedure room and the recovery room. Monitoring necessitates the presence of someone in the room whose primary responsibility is assessing and managing the patient. This person has a significant role in assuring that the subject is stable and that the monitoring ­equipment is functioning properly. Resuscitation equipment must be available should it become ­ necessary. This  includes a functioning suction device, ­oxygen, and intravenous solutions along with a cart equipped with standard emergency resuscitation material. Standard oxygen monitoring equipment should be available. This probe is placed away from the extremity in which arterial access is obtained to ensure that distal vessel spasm or disease, if p ­ resent, does not impair the readings of the ­monitor. There should be continuous monitoring of the electrocardiographic tracing. In some cases, it may also be mandatory to have the a­bility to continuously monitor arterial p ­ ressure. This may be achieved with a separate arterial line, and may be useful in performing carotid stents or in major aortic cases. Arterial pressure monitoring may also be performed as part of the manifold system connected to the arterial sheath. It is helpful to have an additional port off the manifold that allows pressure monitoring. The pressure system can, however, be added to the side arm of the sheath,

attaching the side port of the sheath to a separate pressure monitoring system. In addition to this invasive arterial pressure monitor, it is necessary to have a noninvasive method of monitoring the pressure in case the invasive system is not functioning or is impaired for a period of time during the procedure. Imaging equipment is described in Chapters 8 and 12. The table should be a floatingpoint table that is made of carbon fiber and allows imaging in all rotations. Floating-point tables allow rapid positioning of the table and decrease the time necessary for performing the procedure. It is also helpful to have a sterile tabletop on which to work. In order to move expeditiously through the performance of these procedures, arranging two tables behind the team is helpful. The space offered by an additional “back table” provides an area on which the items to be used are prepared and placed, available in their order of use. The time saved not searching for an item on a crowded surface will easily offset the small space loss incurred by the additional table.

FACILITIES AND ROOM SETUP Inventory items should be assembled prior to the procedure, which should be previewed in a step-bystep manner. It is important to have the facility and room arranged so that the surgeon is comfortable performing the procedure and all the equipment necessary for the procedure is readily available. The room should be large enough to allow movement around the patient and sterile field. The patient should be comfortably positioned. Safety straps and side restraints help maintain patient position and safety. The interventionalist is positioned tableside with easy access to the equipment tables. It is essential to have adequate assistance during these procedures and to ensure that the assistant is well versed in the technique. The assistant should be positioned on the side of the interventionalist and should also have easy access to equipment. The imaging system is best positioned on the opposite side of the table to where the surgeon is located and the monitor bank for images should be positioned at eye level opposite the surgeon. The monitor bank should include three monitors. The first should contain the working images. The second monitor is a reference monitor to allow posting of reference images that can be used to assist with positioning catheters and guidewires. The final monitor

6  Case preparation

should be a physiologic monitor, which contains the o ­ utput of any hemodynamic measurements, oxygen saturation, electrocardiographic tracing, and p ­ ressure measurements. Maximize the potential for s­ uccess in each case. Preprocedure a­ nalysis makes a difference. Practice settings that have some particular disadvantage with respect to setup or equipment can still be made to work, but planning around those issues is essential.

HOW PRETREATMENT HISTORY AND PHYSICAL EXAMINATION HELP TO PLAN THERAPY Your patients will benefit substantially if you go into the procedure with a good sense of how the patient is doing, a good feeling of how strongly indicated the treatment might be, and a reasonable understanding of the whole range of treatment options. Here are some examples of how this information helps. Obtaining a good sense of the history will help to indicate the trajectory of the vascular problem. If it is chronic and the patient is having problems during the procedure, it makes more sense to stop and come back another day. If the problem is more acute, then other factors related to the acute illness may be anticipated. If the patient has profound ischemia, they may not be able to tolerate having the limb on a level surface. If there is significant cardiopulmonary compromise, the patient may not be able to lay flat. It is good to know if palpation of the pulses reveals that the femoral arteries are rock hard. If an antegrade puncture is being considered, does the patient also have a popliteal pulse or could there be occlusive disease near and just inferior to the puncture site? If an upper extremity access is anticipated,

it is good to know what the pulses feel like and also whether the bilateral brachial pressures are equal. Is the skin of the groin that is intended for access clean? Factors such as these help to drive the ­decision-making process that takes place before the procedure even starts.

PRETREATMENT IMAGING Pretreatment imaging, especially noninvasive imaging with duplex ultrasound, magnetic resonance angiography (MRA), or computed tomography angiography (CTA), saves a tremendous amount of grief. It may help you anticipate a puncture site and may show a disease burden that makes certain puncture sites too risky. It may help you decide whether a diagnostic arteriogram is needed prior to the therapeutic procedure. It might also help you know when some type of hybrid ­procedure is better than a purely endovascular procedure. If there is significant calcification, one might consider atherectomy in the case planning for a lower extremity or shy away from a stent in a carotid repair, or it may affect the stent choice in an aortoiliac occlusive case. Understanding the hemodynamics of a limb is also extremely helpful for planning the case and anticipating what the ischemic hand or foot should look like after treatment of specific lesions. Pretreatment imaging also saves a tremendous amount of contrast and intraprocedural time. With angiography, it can occasionally be challenging to identify the exact severity of a lesion. If the severity of the lesion has a bearing on whether or not to treat, such as in the carotid circulation, then some type of preprocedure corroboration of the severity of the lesion should be obtained.

2 Safe and strategic vascular access OVERVIEW OF PERCUTANEOUS ACCESS The simpler and more routine you can make your approach, the fewer complications your patients will experience. Use of the vascular system itself to assist the therapist in arriving at the site of the lesion for treatment has tremendous appeal. It is simple, direct, less morbid, and leaves little external evidence of what has taken place. Much resources and development have been brought to bear in order to make standard open surgery a thing of the past, and this effort has been relatively successful. As devices are miniaturized, guidance more accurate, and closure more secure, vascular access becomes simpler. A well-placed access site sets the operator up for success. A poorly chosen or conducted access can make a simple case complicated and possibly make a complicated case impossible. Access site issues must be considered for every case. Access-related complications are still the most common complications of endovascular intervention. An access mistake almost guarantees a complication. Consider the need for access as a breach of the vascular ­system, a necessary evil that should be minimized as far as possible. Although a percutaneous access site is much smaller than a standard surgical incision, it is still what the patient notices most during the recovery process. Vascular access also has potentially fatal complications associated with it.

Strategy: What are the principles of percutaneous access? 1. Choose the puncture site with the individual patient’s needs in mind.

2. Determine the likelihood of performing an endovascular intervention during the procedure at hand as an extension of the angiogram and take that into account when choosing a puncture site, knowing that the sheath will require upsizing. 3. Pick an access site that is far enough from the lesion that a sheath may be placed without encountering the lesion itself, and gives the operator working room. 4. Feel the artery intended for puncture so you know what to expect. Is it soft or hard, and what is the quality of the pulse? 5. Palpate the anatomic landmarks. For example, with every femoral puncture, the anterosuperior iliac spine, the pubic tubercle, and the inguinal ligament should be defined by physical examination and palpation. 6. Visualize the artery and its relationship to anatomic landmarks before skin puncture. 7. Standardize your technique. 8. Use fluoroscopy for guidance once the wire is introduced. 9. Do not be afraid to abandon the access and puncture elsewhere if the risk is too high. 10. No one gets in every single time. 11. If there is a problem, hold pressure for a few minutes and start again. 12. It is rare to have any significant damage to the access artery from the needle alone. Larger problems occur when a poor puncture placement is not recognized and larger devices are placed through that site. 1 3. In recent years, the use of ultrasound guidance and micropuncture has made access safer.

7

8  Safe and strategic vascular access

CHOOSING YOUR APPROACH The most important maneuver for successful vascular access occurs prior to the procedure, and that is choosing the puncture site. The optimal puncture site choice should provide a low risk of complications and reasonable proximity to the site of intended intervention. Table 2.1 provides a list of puncture sites. The retrograde femoral puncture is the most commonly used since it is safest and offers the highest degree of versatility. In the author’s practice, when a proximal approach is required, the brachial artery puncture is chosen, with preference for the left brachial

artery since the pathway from the right brachial artery crosses the origin of the right common carotid artery and the innominate artery. Many procedures are also being performed using the radial artery, especially diagnostic cardiac catheterization. When upper extremity access is required for a sheath of more than 7-Fr in caliber, it may be obtained using open exposure of the brachial artery. Open axillary artery exposure, with or without a conduit, is typically reserved for larger sheaths or multiple simultaneous sheaths required for aortic branch vessel reconstruction during aortic aneurysm repair. Other puncture sites that have been used less commonly include

Table 2.1  Percutaneous puncture site choices Puncture site

Approach

Provides access to…

Comments

Femoral artery

Retrograde

Aorta and its branches

Antegrade

Ipsilateral infrainguinal

When either femoral artery can be used, most right-handed operators will stand on the patient’s right side and puncture the right common femoral artery Contraindicated when there is inflow disease or a high profunda femoris artery origin or when the patient is obese SFA occlusion or occluded SFA stent with reconstitution of distal SFA that cannot be crossed from antegrade direction Prefer the left side. Access site for sheath larger than 7-Fr should be closed through open exposure. Risk higher than with femoral puncture 6-Fr sheath is maximum. Controlled with local pressure. Alternative to brachial puncture Disadvantage: patient in prone position

Superficial femoral artery (SFA) Brachial artery

Antegrade

Ipsilateral SFA

Retrograde

Aorta and its branches

Radial artery

Retrograde

Aorta and its branches

Retrogeniculate popliteal artery Tibial or pedal artery

Retrograde

Ipsilateral SFA

Retrograde

Ipsilateral SFA, popliteal, tibial

Retrograde

Aorta and its branches

Antegrade

Carotid bifurcation

Common carotid artery

Translumbar

Aorta and its branches

Crossing long occlusions that cannot be crossed from antegrade direction. Requires wire rendezvous technique Increased risk of stroke and bleeding. Usually through open exposure Measure working room to bifurcation; must be minimum of approximately 5 cm, usually through open exposure Prone position, limited to arteriography, increased risk of bleeding. Used primarily for treatment of type II endoleak

Femoral anatomy for arterial access  9

Fig. 2.1  Working forehand. The operator should work forehand whenever possible. In this example, a right-handed surgeon stands on the patient’s right side to puncture either femoral artery. Brachial puncture is also p ­ erformed forehand.

the retrogeniculate popliteal artery and the common carotid  artery. Tibial and pedal arteries have been used for retrograde access to the ipsilateral lower extremity, especially in patients with critical limb ischemia and extensive occlusion that cannot be crossed in the antegrade direction. More information about using tibial and pedal arteries can be found in Chapter 25, which covers complex lower extremity revascularizations. Using this approach has significantly increased the number of patients with chronic lower extremity ischemia that can be treated with endovascular techniques. Translumbar access is only rarely performed for diagnostic procedures but has recently been performed commonly to gain access to a patent aneurysm sac in a patient with an endoleak after stent–graft exclusion of an abdominal aortic aneurysm. Chapter 10 includes a detailed discussion of puncture site evaluation prior to arteriography. Once the puncture site has been chosen, the operator should set up the case so that the work can be performed forehand if possible. The options for a forehand approach are demonstrated in Figure 2.1.

FEMORAL ANATOMY FOR ARTERIAL ACCESS The most common complications following arteriography or endovascular intervention occur at the puncture site. An understanding of the anatomy helps avoid complications. The goal is a single perfect pass of the entry needle in every case. The inguinal ligament extends from the anterosuperior iliac spine to the pubic tubercle. This landmark is usually possible to define by palpation, even in obese patients, and is essential in helping to determine how far superior or inferior the puncture should be. A puncture of the mid-common femoral artery is desirable. Ultrasound guidance is extremely helpful in achieving this goal. Once the location of the inguinal ligament has been defined, the landing of the needle on the artery depends on the angle at which the entry needle passes from the skin to the artery. The quality of the artery may be evaluated prior to the procedure by palpating it. The artery may be rolled under the fingers. A thickerwalled or calcified artery presents as a firm

10  Safe and strategic vascular access

structure that can be rolled a little bit back and forth, and it has more body than just the palpation of a pulse. If the patient has a poor femoral pulse and has stronger pulses more distally, at the popliteal or pedal levels, the common femoral artery is likely calcified. If the patient has a femoral bruit and yet the femoral pulse is stronger than expected, it may be the water hammer effect caused by a lesion in the distal common femoral artery, just distal to the point of palpation. If the artery is not easy to locate because of a diminished pulse, there are several steps that may be taken. These are outlined in the section “Puncture of the pulseless femoral artery”. Fluoroscopy may also be used prior to puncture to locate the head of the femur and identify the artery. Puncture of the artery proximal to the femoral head is likely to be too far proximal and to enter the external iliac artery. The artery usually passes over the medial side of the femoral head. The temptation is to use the groin crease to determine the location of the puncture. Obese patients often have a groin crease that is significantly distal to the location of the inguinal ligament, and this may lead to a puncture that is too low (Figure 2.2). The fossa ovalis may also be palpated as a discontinuity in the fascia of the leg at the location where the saphenous vein dives toward the deeper common femoral vein. Since this is directly over the lower aspect

of the common femoral vein, it may also be used as an anatomic marker, with the femoral artery just lateral (usually the proximal superficial femoral artery [SFA] is present at this level). Occasionally, it is helpful to use a marker on the skin to define the inguinal ligament and the location of the common femoral artery.

PUNCTURE GUIDANCE WITH ULTRASOUND In the author’s practice, ultrasound is used for nearly every puncture, arterial or venous. The likelihood of a clean first pass is higher, as well as a properly placed puncture. Ultrasound provides the opportunity to avoid lesions located near a puncture site and it may help permit the use of a closure device, even in a diseased artery, by helping to avoid a severely calcified area. It also helps avoid a puncture that is too distal or in the side of the artery wall (which is suboptimal for closure). In the case of femoral artery access, where either the right or left side could be punctured, if one side looks severely diseased or the common femoral artery is too short due to a high profunda femoris artery origin, the contralateral side can be accessed instead. In the case of brachial artery puncture, ultrasoundguided access is essential to obtain the cleanest possible vessel entry. There are a couple of

Fig. 2.2  Identifying the anatomic landmarks before arterial puncture. Identification of landmarks for arterial puncture may be challenging in the obese patient. The groin crease is usually substantially distal to the actual inguinal ligament and this must be taken into account when planning femoral access. If you palpate the anterosuperior iliac spine and the pubic tubercle, the location of the inguinal ligament will be more clear.

Puncture guidance with ultrasound  11

situations in which ultrasound is not used. In cases where puncture is being performed distal to an occlusion that could not be crossed in the antegrade direction (e.g., tibial or pedal artery access), ultrasound may be used but direct visualization of the artery may also be achieved by injecting contrast proximal to the occlusion and watching the vessel fill. Otherwise, ultrasound is a routinely used tool that makes endovascular procedures safer. Portable ultrasound machines are being marketed for vascular access and are widely and readily available. The area intended for puncture is surveyed quickly with the ultrasound probe. The depth of the beam and the gain are adjusted. If the artery is difficult to find, locate the vein first, which is larger and easily compressible. Find the vein with the probe in the transverse orientation. After locating the vein, orientation of the probe

A

as to medial and lateral is checked and this gives clues as to where the artery should be anatomically next to the vein. The artery can usually be seen to be pulsatile, thicker walled, noncompressible or minimally compressible, and smaller than the vein. The dynamic presentation of the artery on ultrasound may change depending on flow conditions. In patients with congestive heart failure, the vein may also appear pulsatile. In patients with an occlusion just distal to the insonation site, the artery may appear hyperdynamic. When evaluating the vascular sheath in cross-section (transverse), the vein is larger, thin-walled, and compressible, while the artery is smaller in caliber, thick walled, and pulsatile (Figure 2.3). Ultrasound works well for venous puncture since veins are larger and compressible and can be enlarged by manipulating the patient’s position, but they have no pulse that

B

D

E

C

F

Fig. 2.3  Ultrasound-guided puncture can facilitate access under challenging circumstances. (A) The operator evaluates the artery with the probe in transverse orientation, while inserting the needle at an angle that is anticipated to encounter the artery directly under the beam of the probe. (B) The artery is smaller, thicker walled, and more pulsatile than the vein and is located lateral to the vein. (C) The artery can be followed more distally to observe the location of the common femoral artery bifurcation. At this level, it is usual for the saphenofemoral junction to be visible. (D) Further inferiorly, below the confluence of the profunda femoris and superficial femoral veins, the superficial femoral vein is posterior to the superficial femoral artery. (E) The inguinal ligament may or may not be visible and is typically seen as a uniform, echogenic structure crossing the artery. If a closure device is anticipated, it is safer to be well inferior to the inguinal ligament. (F) Gentle compression with the ultrasound probe causes compression of the common femoral vein while the higher pressure common femoral artery maintains its shape despite the external compression. The pulsatility of the common femoral artery typically becomes more obvious with the maneuver of gentle external compression.

12  Safe and strategic vascular access

can help an operator who is using external landmarks to guide the puncture. The middle of the probe should be placed over the intended puncture site in the artery. Advance the needle at an angle with the intention of having the needle hit the vessel directly under the probe. Needles create a shadow when the sound waves reflect off them and when it is in the field of the ultrasound beam, it is usually readily identified. Needles are also available that have scuffed up tips and are even more visible on ultrasound. When the needle hits the artery, the artery wall can be seen in motion. The operator may have to tap on the anterior artery wall a few times to confirm the position prior to entering the artery.

MICROPUNCTURE TECHNIQUE A coaxial micropuncture set (e.g., Micropuncture® Access Set) includes a 21-gauge needle to enter the

B C

A

Fig. 2.4  This micropuncture set includes: (A) a 21-gauge needle; (B) a 0.018-inch floppy tip guidewire; and (C) a 4-Fr short catheter with an inner 3-Fr trochar to slide over the low-profile guidewire.

artery, a 0.018-inch guidewire with a floppy tip, and a 4-Fr or 5-Fr short catheter with an inner smaller diameter dilator that passes over the wire (Figure 2.4). The 21-gauge needle is placed into the artery. When backbleeding occurs, the soft-tipped, steerable 0.018-inch guidewire is advanced through the needle under fluoroscopic guidance. Arterial backbleeding through a 21-gauge needle is usually much less pulsatile than through the larger 18-gauge needle. The needle is removed and the 4-Fr or 5-Fr short catheter with the 3-Fr inner dilator is passed over the guidewire. After the catheter is in place, the dilator and guidewire are removed. A longer, appropriately sized guidewire (usually 0.035-inch diameter) is passed. The short catheter is removed and the desired access sheath placed. Puncture sites beyond the femoral artery, including the brachial or radial artery, bypass grafts, and alternative access sites, are preferentially approached using the micropuncture technique. When should the micropuncture technique be used? Some operators use it for every case and some use it selectively. It is particularly useful for brachial or radial artery access, for pulseless arteries, scarred groins, and calcified arteries, or for antegrade access to the lower extremity. In the author’s practice, it is used for nearly every case. The advantages of the micropuncture technique include a smaller initial arterial hole, use of a steerable wire, and graduated enlargement between the inner stiff trochar and the 4-Fr or 5-Fr dilator. There are disadvantages of micropuncture. It requires extra steps. The catheter is not long enough so if there is a lesion nearby, you end up crossing it with the introducing guidewire and then crossing it again with the 0.035inch wire required for access sheath placement. If you are working with a scarred groin, a redo groin, or a super calcified femoral artery, the catheter may not pass over the 0.018-inch guidewire. A number of tricks may be required to make up for a guidewire that does not have the backbone to support passage through a hostile scarred area. The advantages of the technique are significant in that it promotes optimal placement, especially when used with ultrasound guidance, and permits the operator to abandon an unacceptable  access with a low chance of ­having done harm.

Percutaneous retrograde puncture of the femoral artery  13

for local anesthetic, a scalpel, a mosquito clamp, a micropuncture set or a puncture needle, and a guidewire) is placed on the patient’s lap. A righthanded operator stands on the patient’s right side for the puncture of either groin so that the forehand approach can be used (Figure  2.5). The femoral artery of choice is palpated and the

PERCUTANEOUS RETROGRADE PUNCTURE OF THE FEMORAL ARTERY Both groins are prepared and draped. A towel holding each of the items immediately required for puncture and guidewire placement (a syringe

A

B

C

D

E

F

Fig. 2.5  Percutaneous retrograde puncture of a femoral artery. (A) A sterile towel is placed on the patient’s lap or on a nearby sterile table with the tools immediately required for percutaneous arterial entry (from left to right): a scalpel, a hemostat, a percutaneous entry needle, a syringe with local anesthetic, and a guidewire. (B) A right-handed operator stands on the patient’s right side for puncture of either femoral artery to permit a forehand approach. If the left femoral artery requires puncture, the operator leans over the patient. (C) The prospective location of the middle to proximal common femoral artery puncture is evaluated by tracing the inguinal ligament from the anterosuperior iliac spine to the pubic tubercle. The artery is trapped between the forefinger and third finger of the operator’s nondominant hand. The thumb and forefinger hold back the surrounding soft tissue, as do the third, fourth, and fifth fingers. When local anesthetic is administered into the subcutaneous tissue, the femoral pulse usually becomes more pronounced. The entry needle approaches the artery at a 45-degree angle. (D) The femoral arteriotomy is safest in the proximal to middle common femoral artery. (E) When pulsatile backbleeding indicates that the needle tip is in the artery, the nondominant hand is released from its position trapping the artery. The nondominant hand accepts the needle and steadies it. (F) The dominant hand retrieves the guidewire, straightens its tip, and inserts it into the needle hub.

14  Safe and strategic vascular access

A

B

C

inguinal ligament traced from the anterosuperior iliac spine to the pubic tubercle. The goal is to puncture the proximal to middle common femoral artery. In most patients this represents a segment 4–8 cm in length. The operator must anticipate the trajectory of the needle with an angle of approach of 45 degrees or steeper. The more calcified or scarred the artery, the more a steep trajectory approach is required in order to spear the artery so that the needle does not simply bounce off it. Guidance with ultrasound is extremely helpful (see “Puncture guidance with ultrasound”). Fluoroscopy also helps in the situation of a heavily calcified artery, because as the needle pushes the hardened artery, the whole structure can be seen moving. The operator uses the nondominant hand to trap the common femoral artery. A right-handed surgeon uses their left hand to trap the artery between the forefinger and the third finger. The third, fourth, and fifth fingers fan out on one side of the artery and the thumb and forefinger on the other side of the artery to hold back the surrounding tissue. The hand is adjusted until the impression of the pulse is equal on the tips of the second and third fingers. Once the left hand (or nondominant hand) is correctly placed, it is not moved again until pulsatile backbleeding

D

Fig. 2.6  Single-wall or doublewall puncture technique. (A) The single-wall puncture 18-gauge entry needle has a beveled tip that is placed into the anterior wall of the artery. The micropuncture needle is a similar but smaller caliber version (21 gauge). (B) The double-wall puncture needle has a trochar with a sharp beveled tip that is inserted through the artery. (C) The trochar is removed. (D) The blunt tip outer casing is then gradually withdrawn until its tip is in the arterial lumen and pulsatile backbleeding is evident. In general, double-wall puncture is of historical interest and has mostly been abandoned.

is coming from the needle. Plain lidocaine (1%) is injected into the skin and subcutaneous tissues in the area for the prospective puncture between the forefinger and the third finger of the operator’s left hand. Infiltration with local anesthetic causes induration and this increases the transmission of femoral artery pulsation to the surrounding soft tissue, which can be appreciated if the fingers are in the correct location. A  No. 18 straight angiographic entry needle is then used to approach the artery at a 45-degree angle. Either a single-wall or a double-wall puncture needle may be used (Figure  2.6). The vessel is usually 2–5 cm beneath the skin entry site. The anterior wall of the common femoral artery can usually be palpated with the tip of the needle and identified by the pulsation of the artery against the needle. The needle tip is advanced through the anterior wall of the artery. Because the anterior wall is usually softer and the posterior wall is more firm, the needle may immediately abut the posterior wall of the common femoral artery. Occasionally, the needle must be withdrawn just slightly to allow guidewire passage (Figure 2.7). When pulsatile backbleeding is achieved, the operator’s nondominant hand is released from its location over the common femoral artery. The  nondominant hand is then used to hold the

Percutaneous retrograde puncture of the femoral artery  15

Fig. 2.7  The guidewire hits the posterior wall. The tip of the needle often pushes the softer anterior wall of the common femoral artery against the thicker posterior wall before it enters the lumen. (A) When the guidewire is advanced through the needle, it hits the posterior wall of the artery and is unable to pass. (B) The needle is withdrawn 1–2 mm and the guidewire is passed again. The needle position against the posterior wall may also be visualized with ultrasound. A

B

C

A

D

B

E

Fig. 2.8  Variability in femoral artery punctures. Entry site complications result from poorly placed femoral artery punctures. (A) Proximal SFA puncture is too low and may cause puncture site thrombosis. The proximal SFA is frequently the site of significant plaque formation. (B) A ­p roximal profunda femoris artery entry is difficult to compress and may result in hemorrhage. Ultrasound guidance is very useful for avoiding unintended puncture of the SFA or profunda femoris artery. (C) The needle tip may disrupt posterior wall common femoral artery plaque. This is more likely in proximity to the bifurcation. (D) Puncture of the distal external iliac artery is contiguous with the retroperitoneal space and is prone to hemorrhage. (E) Ultrasound guidance may not detect the inguinal ligament very well and does not always protect the patient from a groin puncture that is too proximal. After placement of the needle, consider a single radiograph of the needle location. If the tip is proximal to the outline of the femoral head, consider removing the needle and starting again to obtain a lower placement. This helps avoid a retroperitoneal hematoma.

needle until the guidewire can be passed through the needle. At this point, the needle must be held by the nondominant hand since the needle is in an unstable position in the artery and must be secured. The contralateral hand will be busy inserting and advancing the guidewire. The ­several-centimeter floppy tip portion of the guidewire is advanced through the needle until the stiffer portion of

the wire is traversing the arterial entry site. If the lesion is near the puncture site (e.g., distal external iliac  artery lesion), fluoroscopy is initiated immediately. Most puncture site complications are related to arteriotomies that are too high, too low, or forced into an area too hostile for simple puncture (Figure  2.8). The anterior wall of the

16  Safe and strategic vascular access

Strategy: What to do if the guidewire will not pass through the needle

Fig. 2.9  Retroperitoneal hemorrhage from a proximal groin puncture. A groin puncture that is too far proximal may enter the external iliac artery and cause hemorrhage into the retroperitoneal space. If it is unrecognized, pressure at the skin puncture site, which is somewhat distal to the arterial puncture site, may exacerbate hemorrhage by creating additional outflow resistance downstream from the bleeding arteriotomy, as in the example shown. If the abdominal wall is relaxed, manual pressure can often be held satisfactorily over a distal external iliac artery puncture site with a little extra effort.

common femoral artery often has a soft spot, even when the artery and its bifurcation are heavily diseased. Puncture of the external iliac artery is difficult to compress and it is surrounded by the potential space of the retroperitoneum (Figure  2.9). Hemorrhage from a high puncture may require a stent–graft or surgical control. Unfortunately, an external iliac artery puncture is often not recognized until after the access is removed and the patient develops pain or vital sign instability. The proximal profunda femoris artery is also difficult to compress because of its deep course. The proximal SFA is usually calcified and often a site of substantial plaque formation, and puncture site compression at the SFA origin may cause thrombosis. Since common femoral artery plaque forms preferentially along the posterior wall, double-wall puncture confers no advantages and may  add  some  risk,  and  should therefore be avoided.

1. The guidewire may be trapped between the tip of the needle and the posterior wall of the artery. If the tip of the entry needle is against the posterior wall of the artery, withdraw the needle 1–2 mm very slowly while gently attempting to pass the guidewire (Figure 2.7). As the needle pulls back far enough, the guidewire often will pass. 2 . If the guidewire encounters a common femoral artery lesion, irregular posterior wall plaque may be disrupted, form a dissection plane, or embolize. Do not force the guidewire. Tactile feedback is important here and it is a good time to move slowly. Bringing in fluoroscopy at this point is often helpful in order to see the shape and direction of the wire tip. 3. Withdraw the guidewire to ensure that the needle tip is still intra-arterial and that backbleeding is pulsatile. However, if using a hydrophilic guidewire, care must be taken to avoid shearing of the hydrophilic coating of the tip of the wire by the sharp bevel of the needle. 4. Establish that arterial return is consistent with the clinical impression of inflow to that level (e.g., dampened arterial inflow should be expected if the patient has aortoiliac disease). 5. Reinsert the guidewire and use fluoroscopy to see where the wire hangs up. Sometimes, the guidewire goes just beyond the needle tip and into a medial or lateral collateral (Figure 2.10). If the guidewire tip forms a loop or appears to go on a circuitous course just after it exits the needle, do not force it. The wire is likely subintimal and you will probably have to pull it out. 6. If there is appropriate blood return from the needle, put an extension tube on the hub of the needle and puff contrast while under fluoroscopy or use road mapping. Visualize the puncture site and the cause of the obstruction. 7. Consider a new puncture at the same location or a different approach altogether. 8. The needle may be too low and hitting femoral bifurcation plaque. Pull the needle and hold pressure at the arterial puncture site. Repeat the puncture 1–2 cm more proximally along the common femoral artery.

Percutaneous antegrade puncture of the femoral artery  17

A

B

Wire goes in a short distance and then stops as wire tip hits obstruction and begins to curl

D

C

Wire goes out of needle only a short distance then begins to coil up

E

Wire goes up the common femeral arrtery but then goes out into the medial or lateral iliac circumflex arteries

Wire goes in but then goes the wrong direction

F

Floppy tip on the wire forms a loop

Wire passes into iliac artery

Fig. 2.10  Guidewire advancement problems. Some examples of how an advancing guidewire may be hampered are shown. (A) Guidewire tip in a dissection plane. (B) Guidewire encounters a lesion and rolls into a ball. (C) Guidewire redirects itself inferiorly. (D) Guidewire enters a medial or lateral iliac circumflex branch. (E) Guidewire tip forms a loop and then encounters a lesion or friction. (F) The transition point along the guidewire, from the soft floppy tip to the firmer shaft, is at the angle of the needle entry and forces a hesitation in advancement.

PERCUTANEOUS ANTEGRADE PUNCTURE OF THE FEMORAL ARTERY Antegrade femoral artery access permits optimal control of guidewires and catheters for infrainguinal endovascular intervention, especially if tibial or pedal artery treatment is contemplated. The puncture in the skin must be proximal to the level of the inguinal ligament to allow entry of the needle into the proximal to middle common femoral artery, taking into account a 45-degree angle of approach (Figure 2.11). Often a steep approach angle of the needle works best for antegrade puncture. A high puncture in the distal external iliac artery may result in hemorrhage. A distal puncture, which is too near the femoral bifurcation, results in inadequate working room to selectively catheterize the origin of the SFA and may also be in an area where it cannot be safely compressed to achieve hemostasis. A right-handed operator stands on the patient’s left side for forehand delivery of the needle and

guidewire. The image intensifier should hover over the patient from the side opposite the operator. This arrangement may be a problem in an angiographic suite where the C-arm unit is mounted on ceiling rails or on the floor. The left or nondominant hand is used to trap the common femoral artery between the forefinger and the third finger in the same way as for a retrograde femoral artery puncture. The proposed arterial puncture site is visualized in juxtaposition to the location of the inguinal ligament. The skin puncture site is then chosen and infiltrated with 1% plain lidocaine. The angiographic entry needle is advanced at an angle of 45 degrees or steeper toward the pulse, which is trapped between the forefinger and third finger. When pulsatile backbleeding is achieved, the needle is held steady by the dominant hand momentarily. The nondominant hand position over the artery is relinquished. The nondominant hand rests on the patient on its ulnar side and takes over the needle in its intra-arterial position. The dominant hand reaches for the guidewire and inserts

18  Safe and strategic vascular access

A

B

C

D

Fig. 2.11  Percutaneous antegrade puncture of a femoral artery. (A) A right-handed operator stands on the patient’s left side to permit a forehand approach to either femoral artery. A towel is placed on the patient’s lap with the tools needed for arterial puncture. (B) Consider using ultrasound guidance to locate the best puncture site in the artery. If not using ultrasound guidance, the common femoral artery is trapped between the forefinger and third finger of the nondominant hand. The intended arterial puncture site is at the proximal to middle common femoral artery, with the needle approach at 45 degrees. The skin puncture site is proximal to the inguinal ligament. (C) The common femoral artery available for antegrade puncture is limited. Puncture above the inguinal ligament must be avoided because of the risk of hemorrhage. Puncture near the common femoral artery bifurcation leaves inadequate working room for cannulation of the SFA. (D) After the needle tip enters the artery, the position of the nondominant hand is modified to hold the needle rather than trap the artery. The guidewire is advanced with the dominant hand. While using ultrasound guidance, the probe can be turned in the longitudinal orientation to visualize the wire entering the SFA. (Catheterization of the SFA using an angled catheter and an antegrade approach is demonstrated in Chapter 9.)

it into the needle hub. The wire is then advanced with the dominant hand. In patients with a large abdominal pannus, wide silk adhesive tape is used as a truss to hold the pannus back (Figure 2.12). A large pannus is a relative contraindication to the antegrade approach. Using a tape as a truss can be helpful with either a retrograde or an antegrade femoral puncture. It might also help to put the patient in the Trendelenberg position in order to tilt the pannus away from the access site. Since the SFA is on the level plane and the profunda femoris artery proceeds posteriorly from the bifurcation, the guidewire usually enters the profunda femoris artery preferentially following antegrade puncture. The guidewire must be redirected into the origin of the SFA (see Chapter 9

for a detailed discussion of selective catheterization). The working distance between the antegrade puncture site in the common femoral artery and the femoral artery bifurcation is limited. Any previously acquired arteriograms should be assessed to determine the level of the femoral bifurcation. Even if only contralateral lower extremity films are available, evidence of an unusually high femoral bifurcation may alter the puncture site choice. Prior to performing antegrade femoral artery puncture, any previous arteriograms should be checked for the location of the profunda femoris artery origin and the length of the common femoral artery. Duplex ultrasound evaluation and marking of the common femoral artery bifurcation may also be performed before proceeding with antegrade puncture. The micropuncture approach

Percutaneous puncture of a pulseless femoral artery  19

Fig. 2.12  The abdominal pannus can be taped up during the procedure to better expose the femoral areas.

works well for an antegrade puncture. The puncture is small and can be directed under fluoroscopy or ultrasound. The guidewire is relatively steerable and can be rolled between the fingers and twirled into the SFA.

Technique: How do you enter the proximal femoral artery during antegrade femoral puncture? 1. It is best when performing an antegrade approach to enter the proximal common femoral artery to maximize the working distance between the puncture site and the femoral bifurcation. 2 . Use a micropuncture set, which has a guidewire that is somewhat steerable. 3. Under ultrasound guidance, aim to hit the artery even with the very proximal part of the head of the femur, just inferior to the level of

the bony cortex. Go at a sharp angle from the skin down toward the artery if you need to. Put the needle down close to where you think the artery is and then use fluoroscopy to obtain confirmation of the appropriateness of the location. 4 . Calcification can often be visualized, which helps to identify the location of the SFA origin. 5. If the guidewire repeatedly passes into the profunda femoris artery and cannot be passed into the SFA, a catheter is placed to direct the wire. A slightly more robust wire, such as a Rosen wire, is advanced deep into the profunda. A short (40-cm) angle tip 4-Fr catheter, such as a Kumpe catheter, is advanced over the wire. The catheter is slowly withdrawn while contrast is administered. The contrast will reflux into the femoral bifurcation and opacify the proximal SFA. The image intensifier is placed in an anterior oblique position. A road map is created and the catheter used to direct a steerable guidewire, such as a Glidewire®, into the SFA. 6. Once the guidewire is in the artery, guide the catheter down over the wire by pushing on the subcutaneous tissue with a free hand to keep it straight and avoid kinking under the skin. 7. Use ultrasound to visualize the guidewire entering the SFA.

PERCUTANEOUS PUNCTURE OF A PULSELESS FEMORAL ARTERY The clinical situation that requires puncture of a pulseless femoral artery usually includes plans for iliac artery reconstruction or recanalization, rather than simple arteriography. Aortoiliac duplex scanning or CTA is valuable in this setting to assess the severity, location, and length of the lesion. The patent but pulseless femoral artery is cannulated using a combination of several techniques (Figure  2.13). The artery itself is often palpable, even when there is no pulse. The artery can be visualized with ultrasound guidance and this is an excellent indication for this procedure, even in operating rooms where ultrasound guidance is rarely used. The common femoral artery almost always passes over the medial half of the femoral head. Its location may be revealed by a previous arteriogram

20  Safe and strategic vascular access

A B

or is identifiable by vascular calcification using fluoroscopy. A blood pressure cuff placed on the ipsilateral thigh can increase peripheral resistance and enhance a diminished pulse. A catheter can be placed through another access site, either on the contralateral side or the proximal side, and contrast can be injected to road map the femoral artery. Delayed filming is required.

Technique: Fluoroscopically-guided femoral access 1. Mark out anatomic landmarks by palpation. Identify the approximate location of the inguinal ligament. Place a marker, either the needle or a clamp tip, over the location that estimates the correct place to puncture the artery. 2 . Perform fluoroscopy of the femoral area. Often the femoral artery is visible on plain fluoroscopy due to calcification. Check the proximal SFA for calcification because this will indicate the trajectory of the common femoral artery. 3. If the artery is vaguely visible over the femoral head, but you are not sure, use an oblique projection to see if the longitudinal image of the common femoral artery moves with respect to the femoral head. (Because the common femoral artery passes within 1–3 cm anterior to the very sizeable femoral head, completely separating the images of the two structures is almost impossible.

Fig. 2.13  Percutaneous puncture of a ­pulseless femoral artery. (A) The patent but pulseless femoral artery can often be palpated. (B) A review of previous arteriograms shows the location of the artery relative to the femoral head. It usually passes over the medial half of the femoral head.

To separate the image of the two structures requires a very steep oblique, almost lateral projection. At this angle, contralateral structures contaminate the image.) 4. Anesthetize the skin. Advance the needle down toward the artery. If it is really close, the needle will be bobbing with the pulsation of the artery. 5. Do not put the image intensifier too close to the field, so you can work under it. You must be able to see the blood return from the micropuncture needle. Position the intensifier so that the field does not include your hands. There is a lot of scatter in this position so do not perform the procedure for longer than is necessary. 6. When the needle hits the artery, the artery often moves back and forth a bit and becomes a lot more obvious to see on fluoroscopy. If the artery is really rolling back and forth, the other hand can press from the side to provide a little back pressure. 7. A common tendency when starting out with this task is to use fluoroscopy continuously and to use it more than is necessary. There is also a tendency to place the needle at too oblique an angle and end up with the tip of the needle further proximal along the artery than intended. In addition, fluoroscopically-guided puncture is often chosen because the artery is calcified. In this situation, a more direct (not quite straight down, but almost that steep) trajectory works best for puncturing the artery.

Percutaneous puncture of the brachial artery  21

When to start over again with a femoral artery access? Femoral artery access is the author’s usual method of entering the vascular system. There are situations in which it makes sense to stop at some point during the access and change to another option. If the arterial puncture is too high, so that it is through the inguinal ligament or into the external iliac artery, it is best to stop and hold pressure rather than enlarging the access site. If therapy is intended and the artery is so hard that a smallbore sheath will not go in or causes excessive pain, consider an alternative access. If the puncture site is near a preocclusive lesion, this is a situation where a larger sheath may result in low flow past the access site or even puncture site thrombosis, or disruption of the lesion near the puncture site.

PROXIMAL ACCESS Proximal access may be secured through percutaneous or open approaches to the brachial artery or a percutaneous approach to the radial artery (Figure  2.14). Axillary artery puncture was used in the past for arteriography but this is rarely done nowadays. It is much more common to use the brachial artery or radial artery for access. The brachial artery may be punctured and managed percutaneously or using an open exposure. Another option is to enter the artery percutaneously and, if there is any problem, take the sheath out using open exposure and direct suture closure. Diagnostic studies and therapeutic procedures may be performed through the radial artery. This has been developed primarily for coronary intervention, where

A

the caliber and distance requirements are fairly standardized. Advantages of the proximal approach include  the following: (1) it provides an alternative to the transfemoral approach when the femoral puncture sites are hostile or when the pathway between the groin and the pathology is blocked; (2)  when a femoral approach is not possible for some reason, it provides an opposite approach for crossing some lesions in certain arteries. There are several disadvantages to a proximal approach. Although percutaneous puncture can be safely performed, the complication rate is higher and the complications are generally worse when they occur. The arteries of the upper extremity are smaller, less forgiving, and more prone to spasm than arteries of the lower extremity. A constrictive fascial sheath encircles the artery and nerves in the upper arm, and a small hematoma may be enough to cause a brachial plexopathy. Passage of larger endovascular devices for the performance of procedures more complex than arteriography is accompanied by a proportionately greater risk of puncture site complications. The extra distance from the proximal access site to the infrarenal vasculature requires longer guidewires and catheters, which are more cumbersome and less responsive to manipulation.

PERCUTANEOUS PUNCTURE OF THE BRACHIAL ARTERY The most common location for brachial artery puncture is just proximal to the antecubital crease. The left side is the first choice since the carotid artery origin may be avoided. In average-sized patients, sheaths up to 6-Fr may be placed without

B

Fig. 2.14  Proximal access. Brachial or axillary artery entry is usually performed on the left side. (A) Brachial artery cutdown is performed just proximal to the antecubital crease. (B) A brachial artery puncture may be performed at the same location.

22  Safe and strategic vascular access

major risk of puncture site hemorrhage or thrombosis. Open access should be considered for larger devices or in smaller individuals. The patient’s arm is abducted and placed on an armboard (Figure  2.15). A circumferential preparation of the arm is performed. The brachial artery pulse is palpated just proximal to the antecubital crease where the biceps has generally thinned to its tendinous portion. Ultrasound guidance is strongly recommended. If not available, the artery can be trapped between the forefinger and the third finger of the nondominant hand. The tips of the two fingers are held at enough distance to allow the artery to pass

underneath without compressing it significantly. The 21-gauge micropuncture needle is advanced at a 45-degree angle by the dominant hand. The goal is for the needle tip to enter the anterior wall of the artery in the space between the two fingers. When backbleeding occurs, a short 0.018-inch diameter guidewire is passed. Backbleeding through the micropuncture needle is usually not pulsatile because of its small caliber. The needle must be moved and manipulated slowly and any backbleeding carefully assessed. Heparin is administered to prevent thrombosis. Intra-arterial nitroglycerine or papaverine may be required if spasm of the upper extremity

B

C

D

A

E

Fig. 2.15  Percutaneous puncture of the brachial artery. This should be considered for interventions requiring a sheath of 6-Fr or less. (A) The left arm is fully abducted. (B) The brachial artery is trapped between the forefinger and third finger just proximal to the antecubital crease. A 21-gauge micropuncture needle is advanced into the artery. (C) A 0.018-inch guidewire is advanced through the needle. (D) A coaxial dilator system is advanced over the guidewire. (E) After the 0.018-inch guidewire and the inner 3-Fr trochar have been removed, a 4-Fr ­catheter may be used to introduce the desired wire for the case.

Percutaneous puncture of bypass grafts  23

arteries occurs. Ultrasound can be used to visualize the guidewire advancing into the axillary artery. If the brachial artery is really small (less than 3–4 mm), consider moving to the contralateral side. Such patients may have a high origin of the radial artery.

ALTERNATIVE ACCESS TO THE LOWER EXTREMITY: SUPERFICIAL FEMORAL, POPLITEAL, TIBIAL, AND PEDAL ARTERIES In situations where lower extremity access from the femoral level alone is not adequate for crossing the lesion, other options include direct puncture of the lower extremity artery at the level of the superficial femoral, popliteal, tibial or pedal arteries. This is almost always used for retrograde access distal to a lesion that could not be crossed in the antegrade direction. Therefore, by definition, this is usually a secondary access and not the primary access used to perform therapy. More information about this can be found in Chapter 25, which covers complex lower extremity revascularizations. There is also a brief description of the approach to secondary lower extremity access. The most common of these approaches is a tibial or pedal puncture for a secondary retrograde access. The puncture may be anywhere along the length of the posterior or anterior tibial artery or the dorsalis pedis artery. The clinical scenario is usually one in which antegrade femoral or up-and-over femoral access has been obtained and an attempt has been made from an antegrade direction to cross a superficial femoral, popliteal, or tibial artery occlusion or, often, a combination of these. When re-entry cannot be obtained to the true lumen, a retrograde access can be performed. The access itself may be performed under ultrasound guidance using a smaller hockey stick probe or it may be performed by direct and angiographic visualization. In the tibial and pedal vessels distal to an occlusion, flow is usually fairly slow. Therefore, contrast may be administered through the femoral sheath proximally and, as it enters the intended puncture site, the artery can be punctured real time or a road mapping can be performed. A  4-Fr micropuncture set is the best option, u sually with a 4-cm length, 21-gauge needle. ­

The guidewire from the micropuncture set may be used to enter the vasculature or one might use a V-18™ ControlWire Guidewire. This guidewire is 0.018 inches in diameter, has a hydrophilic tip, is good for encountering chronic total occlusions, and has a fairly stiff shaft. It is usually best to support the guidewire at the access site using the 4-Fr micropuncture sheath or even the 3-Fr micropuncture trochar. With the development of tibial and pedal artery punctures, use of the popliteal artery for access has been less common in the author’s practice. The challenge with the popliteal artery is that the patient must be in the prone position. This complicates any other access that there may be to the femoral artery. The popliteal vein is a useful access site for venous thrombolysis and is readily available for puncture under ultrasound. The SFA may also be used directly for retrograde access with the patient in the supine position. The usual place to do this is at the level of the adductor canal. Cases where this might be used are where a patient has a very heavily calcified SFA occlusion or an occluded stent that cannot be crossed. This structure may be punctured directly. Very often in these cases, the artery is easily visible under fluoroscopy because of the calcification or the occluded stent and it can be punctured fluoroscopically. A 0.018-inch diameter guidewire, such as a V-18™ , is inserted and supported with the micropuncture sheath or with the standard 4-Fr access sheath.

PERCUTANEOUS PUNCTURE OF BYPASS GRAFTS Substantial scar tissue may surround a prosthetic graft, especially in an area where an extensive open arterial exposure was performed. This is most common in the femoral area. Antibiotics are administered prior to puncture. Positioning of the patient is the same as for standard retrograde femoral artery puncture. ­ The position of needle entry should be proximal to the anastomosis with the native artery so that anastomotic sutures and/or thrombi are not disrupted. Dacron grafts have a tightly knitted fabric matrix that may be challenging to puncture. Considerable force may be required to push the needle through the anterior wall of the prosthetic graft. Care should be taken to avoid

24  Safe and strategic vascular access

pushing the needle through the back wall of the graft, especially if the graft is not yet well incorporated. A 4-Fr micropuncture set is useful for this task. If the graft is resistant to advancement of the 4-Fr dilator, advance the 3-Fr trochar or inner dilator and then gradually upsize until the desired sheath is in place. Attempt to minimize the size of the sheath since closure is not usually performed for hemostasis. Percutaneous puncture may also be performed on a prosthetic graft that is immediately subcutaneous. The most common situation that calls for this is evaluation of a dialysis access graft. Occasionally, an axillofemoral, femoral–femoral, or infrainguinal bypass graft requires direct puncture. Local anesthetic is injected into the skin and subcutaneous tissue over the graft. No skin incision is made. The needle tip is used to puncture the skin and travel several millimeters in the subcutaneous tissue parallel to the graft. The needle hub is then tipped away from the skin so that the needle is at a 45-degree angle to the graft. The tip of the needle is then inserted into the graft. This maneuver creates a short subcutaneous tract that will help protect the graft from infection. It also helps with hemostasis. The needle should be introduced at 45 degrees or more to avoid a larger, oval-shaped, or skiving type of puncture site hole in the graft, which may be more difficult to control. After the guidewire is placed, introduce the smallest caliber catheter that is adequate for the intended purpose.

Since these puncture sites are usually away from anastomoses, they are less subject to extensive scarring around the graft. Occasionally, a femoral artery that serves as inflow for an autogenous infrainguinal bypass graft requires puncture. Aim for the hood of the graft or more proximally along the artery. The hood of the graft is usually where the pulse is felt most easily. Use clips and any femoral calcification seen on fluoroscopy as landmarks.

PUNCTURE SITE COMPLICATIONS The most common type of complication in endovascular care is related to access. Complications of arterial puncture are listed in Table 2.2. The rates presented were accumulated using various techniques but do not include those patients who have undergone closure procedures at the puncture sites. The worst complications the author has seen are side branch punctures and side wall punctures.

SUMMARY OF PUNCTURE SITE OPTIONS AND CLOSURE STRATEGY Puncture site options and their relative rates of risk are summarized in Table 2.3. The retrograde femoral puncture is by far the most common and the most useful approach. Antegrade femoral puncture is limited in its use to the

Table 2.2  Complications of femoral artery puncture and catheterization Complication Minor bleeding or hematoma Major bleeding or hematoma (requiring transfusion, surgery, or delayed discharge) Pseudoaneurysm Arteriovenous fistula Occlusion (thrombosis or dissection) Perforation Distal embolization Infection

Frequency (%)a

SCVIR complication threshold (%)b

6.0–10.0 1.0–2.4

3.0

0.5–5.0 0.01–0.1 0.3–1.0 250 seconds. 2 . Maintain any guidewire that is in the distal affected vascular bed. 3. Inspect sheaths that are already in place. Aspirate and flush. 4. Administer vasodilators.

Technical aspects of balloon angioplasty in different vascular beds  219

5. Consider the cause. Is the embolus from the angioplasty site or the access site, or is it due to thrombus formation from low flow? The usual cause is embolization from an upstream treatment site. 6. Stabilize the angioplasty site as soon as possible. This usually means stent placement. 7. Place a multiple side hole catheter distally into the affected outflow bed and perform local arteriography. Administer tissue plasminogen activator; several milligrams can be administered as a pulse spray over 10 minutes. 8. Use an aspiration catheter, such as an Export® AP Aspiration Catheter or a Pronto® LP Extraction Catheter, and aspirate the runoff bed as much as possible. 9. Repeat the arteriography. 10. If filling defects continue, continue tissue plasminogen activator at 1 mg/hour. 11. Use mechanical thrombolysis with laser or an AngioJet™ Peripheral Thrombectomy System or aspiration thrombectomy with a Penumbra Aspiration Device.

MANAGEMENT OF ACUTE OCCLUSION An acute occlusion at the angioplasty site that occurs immediately after balloon angioplasty and is apparent on a completion arteriogram is usually caused by dissection (Figures 18.11 and 18.12). A  stent is placed at the same site where the balloon angioplasty was performed to force back in place the dissection flap that has been elevated and propagated from the angioplasty site. After placement of a single stent, arteriography usually demonstrates patency. If necessary, additional stents are placed distally and proximally to the first stent until patency is achieved.

TECHNICAL ASPECTS OF BALLOON ANGIOPLASTY IN DIFFERENT VASCULAR BEDS Considerations of balloon angioplasty vary from one vascular bed to another (Table 18.2). Carotid bifurcation lesions are typically focal and it is usually possible to achieve full balloon expansion. One possible exception to this is when a circumferentially calcified lesion is present. One possible mechanism of stroke with carotid angioplasty is

A

B

C

D

E Fig. 18.11  Management of acute occlusion at the angioplasty site. The most common cause of acute occlusion after angioplasty is dissection. (A) A dissection flap is raised at the angioplasty site that is occluding flow. (B) A catheter is passed over the guidewire and limited arteriography is performed. This attempt to do proximal arteriography is optional. If the operator believes that some other factor is at play, such as thrombosis, an arteriogram is helpful. If the overwhelming likelihood is occlusion due to severe dissection, proceeding to stent placement is probably most expeditious. (C) A stent delivery catheter is passed, in this case carrying a balloon-expandable stent, through the sheath and across the original angioplasty site. (D) The balloon is inflated to deploy the stent at the site of the dissection. (E) The dissection flap opened and secured by the stent.

release of particulate with overaggressive balloon dilation. Carotid angioplasty is followed by carotid stent placement. The angioplasty experience with lesions of the great vessels varies significantly based on lesion location. Lesions at the origin of the innominate artery, left common carotid artery or left subclavian artery tend to be spillover of highly calcified plaque from the aortic arch. Because this is calcified and is spillover, it is frequently circumferential, which is recalcitrant to dilation. Balloonexpandable stents are usually placed in these positions. Stents should be avoided in the axillary

220  More about balloon angioplasty: Keeping out of trouble

A

B

C

Fig. 18.12  Stent placement after dissection. (A) Balloon angioplasty of a focal, common iliac artery lesion causes a dissection. (B) The dissection is identified by the appearance of contrast retained in the arterial wall, flow streaming effects through the lumen, and extension of abnormality well beyond the original lesion. Guidewire access is carefully maintained. (C) Stent placement at the original angioplasty site usually closes the false channels. Table 18.2  Technical aspects of angioplasty in different vascular beds Easily dilated

Need a stent

Causes spasm

Embolization risk

Comments

Carotid Great vessel origin Subclavian Axillary

Yes No

Always Always

Frequent No

High Moderate

Arch dissection is a risk

Usually Yes

Usually Usually not

Occasional Frequent

Low Low

Brachial Aorta Renal Visceral

Yes Usually Usually No

No Usually Yes Yes

Frequent No Occasional Rare

Iliac SFA–popliteal Tibial Pedal

Yes* Yes* Yes Often not

Usually Often Occasionally No

Rare Rare Occasionally Often

Low Moderate Low Moderate to nominal Low Low Low No

Visualize vertebral origin Not a good place for a stent

Stent frequently will not expand

Abbreviation:  SFA, superficial femoral artery. * unless heavily calcified.

and brachial arteries. Lesions in these locations that are clinically significant are unusual and may be due to thoracic outlet syndrome in the case of the axillary artery or to humerus injuries in the case of the brachial artery. Balloon angioplasty of the aorta can release a tremendous amount of debris. Avoid this if there is evidence of ectasia and definitely do not perform angioplasty of an aneurysm. Sizing for the infrarenal aorta can also be difficult, since

many patients who develop clinically significant occlusive disease of the infrarenal aorta also have small arteries. Careful consideration must be taken of the inferior mesenteric artery and whether or not it is a significant supply to the left colon. Renal and visceral angioplasty likewise frequently do not result in significant lumen gain since it is usually plaque that has spilled over from the aorta and is heavily calcified. These arteries almost always

Assessing the acute results of balloon angioplasty  221

undergo stent placement. Angioplasty of the iliac artery can result in rupture. Availability of covered stents is helpful. Iliac angioplasty that causes pain is typically at the limit of the artery’s expansion. If pain does not resolve on deflating the balloon, this could be a sign of injury with leakage into the retroperitoneum. The superficial femoral and popliteal arteries often contain very long lesions. It is helpful to use a balloon that covers as much of the lesion as possible in a single inflation. A long slow inflation, a 1.1 to 1 ratio of balloon to artery diameter, and a prolonged inflation are all helpful for achieving lumen gain. In the tibial vessels the size of the artery is commonly underestimated due to the diffuse narrowing of the lumen, even on what appears to be a widely patent artery. Pedal angioplasty is performed with some regularity but is not yet proven in terms of its patency and how best it should be done.

ASSESSING THE ACUTE RESULTS OF BALLOON ANGIOPLASTY Completion angiography A completion angiogram should be obtained on every case. Typically, access across the lesion is maintained until this exercise has been completed. It should be performed and compared with the pretreatment angiogram. Any evidence of a technical defect should be treated. If it is unclear whether the results show lack of technical defect, one might consider other views.

When to include oblique views Oblique views may be obtained of almost any vessel, but are usually not necessary in a routine case. In high-stakes situations, such as carotid stenting or long segment drug-coated balloon angioplasty in the lower extremity, oblique views are common. Different views of the foot (usually AP and lateral) are usually helpful in below-the-knee cases, and especially if pedal angioplasty is being considered.

When to include runoff Understanding runoff from the target vessel treatment site is always helpful, often necessary,

and frequently neglected. If there is renal insufficiency and limitations on contrast, this is one area in which compromise can be considered. Any patient being treated for tissue loss, management of an occlusion, or long segment disease should have runoff evaluated before and after treatment.

Measure pressure Pressure may be measured across a lesion if it helps to clarify a specific plan. A pressure wire can be passed across the lesion and this allows measurement even in small caliber vessels. Pressure distal to the lesion is measured using a pressure wire or a catheter and is compared with the pressure measured at the sheath tip, which is proximal to the lesion. Alternatively, a pull back pressure can be assessed by pulling back a pressure wire or a pressure measuring catheter across the lesion. The threshold for a significant pressure gradient is typically considered to be around 10 mmHg systolic. Pressure fluctuations during the procedure may hamper the ability to clearly measure the pressure gradient.

Intravascular ultrasound This involves an ultrasound transducer mounted on the tip of a catheter. IVUS can be used to assess the results of angioplasty. IVUS is used to obtain a cross-sectional view and measure the degree of residual stenosis or assess the severity of dissections. These sections in particular may cause flow limitation without this being visible on an arteriogram. If a large amount of tissue is protruding into the lumen, it should be treated to prevent acute occlusion and/or later restenosis.

Intraoperative duplex ultrasound May be used by externally evaluating the vessel with a sterile ultrasound probe. Intraoperative duplex ultrasound is particularly helpful after open surgery such as carotid or femoral endarterectomy, femoral-to-popliteal bypass, or femoral-to-tibial bypass. It can also be used following long segment SFA stenting by transcutaneous evaluation of the artery during the operative procedure.

19 Stents, covered stents, stent–grafts IMPACT OF STENTS Vascular stents have made it possible to reline a diseased artery. Stents have had a major impact on the development of endovascular surgery, which is manifested in four ways: 1. The complications of balloon angioplasty, such as dissection and residual stenosis, may be immediately treated. 2 . Lesions that otherwise would have required open surgery, such as occlusions, long lesions, or recurrent stenoses, may be treated with endovascular surgery. This is particularly appropriate when it provides an additional option for the treatment of patients who are at high risk for open surgery. 3. The overall spectrum of arterial lesions that can be approached with endovascular techniques has broadened dramatically. Whether or not a particular lesion ultimately requires stent placement, the availability of stents has permanently altered the general approach and the consideration of options. 4. Combining stents with graft material to create covered stents or stent–grafts has permitted the endovascular treatment of aneurysmal disease or exclusion of disease that requires treatment due to its complexity. Each stent application has its own cost and complication risks. The sheath must usually be upsized, a foreign body is implanted, and stents have their own unique complications. Stents in some locations, such as the lower extremity or the renal artery, seem to be particularly susceptible to recurrent stenosis. The cost of each stent increases the overall cost of an endovascular intervention.

The placing of stents may be motivated by the wish to extend the short- or long-term success of balloon angioplasty, to avoid surgery, or to avoid repeat balloon angioplasty, but this should be considered in each case. Stents have improved to the point where they can be easily and smoothly incorporated into a procedure, even if a stent was not necessarily intended from the start of the case. Drug-eluting stents have the potential, once fully developed, to decrease or prevent intimal hyperplasia.

STENT CHOICES Stents are either balloon-expandable or selfexpanding (Figure 19.1). The main characteristics of these two types of stents are listed in Table 19.1. The Palmaz™ Stent was the original balloonexpandable stent design. Numerous different designs for balloon-expandable stents are available currently. The Palmaz™ Stent is a straight, metal, relatively rigid, and balloon-expandable cylinder. Balloon-expandable stents have a high level of resistive force or crush resistance, but once the stent is implanted it exerts no chronic outward force because it is fixed. The stent is precrimped onto a standard angioplasty balloon and is deployed when the balloon is inflated. Initially, the stent had to be hand crimped onto the balloon catheter. Now the stents are premounted on the balloon catheters when ordered. The rigid balloonexpandable stent has excellent hoop strength but can be crimped by external forces. These stents perform best when placed in locations that have limited mobility, such as the aortic bifurcation. Balloon-expandable stents perform best when they are relatively short in length, since they are rigid. These stents also shorten slightly as they expand in diameter. Most renal artery stents are less than 223

224  Stents, covered stents, stent–grafts

A

B

C

D Fig. 19.1  Stent choices. (A) Balloon-expandable stents are rigid. The stent is crimped onto an angioplasty balloon and deployed by balloon inflation. (B) Self-expanding stents made of nitinol, a nickel-titanium alloy, are flexible and may be delivered on low-profile catheters. Their outward force and flexibility are substantially influenced by the degree to which the sequence of rings that comprise the stent are connected to each other. (C) Woven nitinol stents (Supera®) have high crush resistance and high flexibility. (D) The self-expanding, wire mesh closed cell stents are made of Elgiloy ®, a metal alloy (Wallstent ®).

2 cm in length and most iliac artery stents are 4 cm or longer. These are the places where balloonexpandable stents are most useful. They are commonly used to treat arch branch origin lesions; in addition to the renal arteries, they are also useful at the origin of the inomminate, carotid, subclavian, and visceral arteries. In the lower extremity, there is a much higher degree of mobility, which promotes intimal hyperplasia, and there is also less surrounding tissue, which exposes the stent to external crush forces. Since we have no bailout stents for the tibial vessels, coronary drug-eluting stents are sometimes used in an off-label manner to deal with this challenge. The medium Palmaz™ Stent can be expanded from a diameter of 4.0 mm to 9.0 mm and the large stent can be expanded from 8.0 mm to 12.0 mm. An aortic stent is also available that can be expanded to more than 2 cm in diameter. This may be used to stent the infrarenal aorta for occlusive disease or the aortic neck in the treatment of a Type I endoleak after endovascular exclusion of an abdominal aortic aneurysm. The Wallstent® is made of Elgiloy®, a stainless steal alloy, and is a flexible, self-expanding, wire mesh tube that is deployed by retracting a covering sheath. It is used today mainly for deep vein and carotid bifurcation stenting. Self-expanding stents are now more commonly constructed of nitinol, a nickel-titanium alloy that has thermal memory and  a high degree of contourability. Nitinol self-expanding stents are used commonly in the iliac,  superficial femoral, and popliteal arteries. Self-expanding stents are packaged on their own delivery catheters. They are intentionally oversized at the time of deployment in the artery, usually by 1–2  mm, and they maintain continual outward radial force after deployment. Self-expanding stents

Table 19.1  Stent characteristics Balloon-expandable stent

Self-expanding stent

Slotted-tube design High resistive force Rigid (do not oversize) Most functional at short lengths Premounted, or mount onto balloon of choice Some shortening with expansion Stainless steel, cobalt, chromium Moderate radiopacity

Wire mesh or slotted tube Chronic outward radial force (oversize for vessel) Flexible Longer lengths very functional Delivery catheter with covering sheath Variable shortening; some do not shorten Nitinol or metal alloy Poor radiopacity (most have markers)

Covered stents  225

are not as susceptible to damage from external forces since they are more flexible, but they have  much less hoop strength than balloon-expandable stents. Self-expanding stents cover more distance and there are some available that could cover most of a superficial femoral artery (SFA) (20–25 cm). They are more difficult to place with great accuracy. Self-expanding stents are deployed from the direction of the tip of the delivery catheter to the hub of the delivery catheter. Therefore, the leading edge of a self-expanding stent can be placed very accurately, but the trailing end cannot be placed with as much accuracy. This requires experience and some guesswork. The vessel must be prepared so that the stent can fully open within the lumen. After a self-expanding stent is placed, poststent placement balloon angioplasty is performed in the hope of having the stent fully expanded and gaining as much lumen as possible. Self-expanding nitinol stents can be open cell or closed cell. Open cell stents have fewer metal-to-metal connections; this makes them more flexible but also with a little less outward force. This may be important in stenting of the carotid bifurcation. In some lesions, greater flexibility may be required to conform to a tortuous artery. In other lesions, higher outward force and a little more densely packed metal coverage of a lesion may be desirable, as is found in closed cell stents. Self-expanding nitinol stents can also be tapered, which might be useful in a carotid bifurcation stent. There is also a helical stent, which is intended to create a swirling flow pattern with the idea of reducing restenosis when treating a lengthy lesion in the femoropopliteal segment. Woven nitinol stents are also available and have very different features from other self-expanding stents. They are produced by weaving separate nitinol wires together. The stent is delivered in rings, and it bears some similarity to a “slinky”. The operator has a lot of control on how tightly to pack the rings. This type of stent has a high degree of crush resistance and has the ability to stand up to severe calcification in a manner than standard self-expanding nitinol stents generally do not. Woven nitinol stents, in order to achieve nominal deployment, require that the artery is well prepared. Vessel preparation must be performed, usually with balloon angioplasty or angioplasty with modified balloons, such as scoring balloons, to gain adequate lumen. Self-expanding and balloon-expandable stents tend to play complementary roles. Deciding which

type of stent to use may be subjective from one practice to another, but endovascular specialists must become facile with the use of each of these two general stent types. In addition, numerous stents, both balloon- and self-expanding, are available. These compete with one another and have continued to improve with each iteration. Balloon-expandable stents are for the most part reliably premounted, have become lower profile with each generation and easier to deliver, and continue to have excellent hoop strength, while being constructed of less metal than once was required. Self-expanding stents have a variety of designs, as described above, adding to flexibility to the inventory. Self-expanding stents are useful in more flexible arteries. Delivery has improved and tends to be more accurate than was previously possible.

COVERED STENTS A variety of covered stents are available that may be very helpful in the peripheral vasculature and can be used for occlusive disease, aneurysms, and trauma. Self-expanding covered stents include Viabahn® and Fluency®. Balloon-expandable covered stents with a polytetrafluoroethylene (PTFE) covering are available from several companies. Covered stents have tremendous utility in trauma and in iatrogenic trauma and can be used as a bridge to definitive therapy, which can be performed under more elective circumstances. Covered stents or stent–grafts can be used to treat aneurysmal disease of almost any vascular bed. The treatment of popliteal aneurysm has evolved in recent years to include stent–graft treatment with Viabahn® in selected patients. There is also increasing evidence for the use of covered stents in occlusive disease, especially in the aortoiliac system, and to consider when reconstructing the aortic bifurcation. In general, the sheath that is required is dependent on the diameter of the covered stent and tends to be larger than a bare metal noncovered stent. Self-expanding covered stents may be used  in the same flexible locations where noncovered self-expanding stents are used, such as the SFA. Self-expanding covered stents are also extremely helpful for the acute management of trauma, either as a definitive repair or as a bridge to therapy in a more elective setting. Iatrogenic injuries to the carotid, subclavian, axillary, iliac, superficial femoral, popliteal, and other vessels can be treated with

226  Stents, covered stents, stent–grafts

self-expanding covered stents. One major challenge with self-expanding covered stents is graft sizing. Because they are self-expanding, they must be oversized slightly to fill the lumen and provide adequate radial outward force. However, if they are oversized too much, there will be an abundance of redundant material, which may be associated with thrombosis. The best methods of sizing the artery include IVUS, qualitative angiography, and fluoroscopic evaluation with an expanded balloon of a known size, and then follow the instructions for use carefully. Balloon-expandable covered stents may be used in arteries that are less flexible, such as the iliac arteries. They may be used to reconstruct the aortic bifurcation and are also helpful as parallel grafts for major branch preservation during endograft treatment of pararenal aortic aneurysms or abdominal aortic aneurysms that present with a short proximal neck. Parallel grafts with covered stents are performed to improve the landing zone for the aortic stent graft in this situation. In addition to sheath size, there are other issues for consideration. Stent–grafts are more expensive. They also cover collateral vessels and, occasionally, branches. In the case of lower extremity occlusive disease, covering collaterals from the SFA or popliteal artery may have later negative effects, especially if the covered stent should occlude at a later time. An advantage of covered stent usage in occlusive disease is that in-stent restenosis does not occur due to intimal hyperplastic growth through the interstices of the stent. Covered stents do tend to develop stenosis at the ends of the stent; this is the so-called “candy wrapper” type lesion. This can be minimized with appropriate sizing of the stent and this lesion is usually readily detectable with duplex surveillance and, because it is focal, is readily treatable.

INDICATIONS FOR STENTS: PRIMARY OR SELECTIVE STENT PLACEMENT There is a key difference between primary and selective stent placement: with primary placement the operator intends in the planning of the procedure that a stent will be placed whereas with the selective approach the operator must decide during the procedure whether a stent is required. When primary stent placement is practiced, the

operator still needs to have enough space in the lesion to deliver the stent. Therefore, predilation or vessel preparation may still be required. The concept of primary stent placement presupposes that the patient is better off with a stent, regardless of the results of treatment of the lesion with balloon angioplasty or other tool. Primary stent placement has made endovascular intervention a very reasonable option in some areas of treatment, for example for renal artery origin lesions. This approach is also used for carotid bifurcation and aortoiliac occlusive disease. The idea behind primary stent placement is that the short- and/or long-term results are generally improved with stent placement to the point where it justifies the upfront increase in cost. As stents have become more reliable, more sophisticated, and more user friendly, and additional data are gathered, it has made more sense to consider stent placement in more situations. Selective stent placement assumes that the cost and risk of stent placement are not justified in every case and that not every patient requires a stent to have acceptable treatment results. Balloon angioplasty was widely practiced for more than 15  years before stents became available. The experience with balloon angioplasty yielded reasonable long-term results for many aortoiliac, infrainguinal, and nonorifice renal lesions, and some upper extremity lesions. After balloon angioplasty is performed, the results are assessed. If the results are not acceptable, stent placement is performed. Indications for selective stent placement after balloon angioplasty include residual stenosis, a persistent pressure gradient, and significant dissection. Other definitive and potentially stand-alone ­t reatments such as atherectomy, scoring balloon angioplasty, or drugcoated balloon angioplasty might also be followed by selective stent placement in certain situations. The indications for stents have expanded steadily since they became available. Endovascular specialists have become more adept at placing stents, and the development of new stents and simpler ways of placing them have assisted in this process. In the management of peripheral arterial occlusive disease, each stent added to the mix in a given case also brings the entire process closer to a point of diminishing returns from a standpoint of cost and the potential long-term disadvantages of overall metal burden. The temptation with stents is to continue to lay them in place until the entire

Which lesions should be stented?  227

arterial tree appears to be perfect. The “stack of stents” phenomenon should be avoided. In most vascular beds, stent placement has become readily accepted. In general, stents are placed at the carotid bifurcation, at aortic branch origin lesions, and in the aortoiliac segment. Stents are used selectively in the lower extremities. Stents are avoided in certain highly mobile ­locations where they may be crushed, such as the subclavian–axillary artery near the first rib and the arteries of the mid- and distal lower leg and ankle. The distribution of disease is such that the lower extremity arteries comprise a significant part of vascular practice. The stent versus no stent debate is more nuanced in the femoral, popliteal, and tibial vessels than it is in most other locations. There are numerous stents available for use in the SFA and popliteal artery. Self-expanding nitinol stents, woven nitinol stents, and drug-eluting self-expanding nitinol stents are all approved for the SFA and proximal popliteal artery. Stenting of longer lesions has worse outcomes than stenting of shorter lesions. In-stent restenosis remains a problem and tends to be worse in longer lesions. Stent occlusion in the lower extremity has a higher than desirable recurrence rate, no matter how it is treated. Oversizing of stents, strut size, material used, and length of disease all affect the long-term outcome. Balloon-expandable stents have not been helpful for the SFA or popliteal artery. The stents that are approved in the US are typically approved for the SFA and very proximal popliteal artery. A couple of stents have been approved for the popliteal artery, and the considerations there are usually different due to the high degree of flexibility and the presence of collaterals. There are no stents approved in the US for the below-the-knee arteries or tibial arteries. Balloon-expandable coronary stents can be considered for bailout of inadequate results of angioplasty below the knee. Additional challenges in the below the knee arteries include the length of the artery, the smaller caliber and lower flow, the lack of a specifically designed stent, and the exposure of these areas anatomically to external crush forces. In the short term, stents have better results than angioplasty in the SFA and popliteal artery. In the long term, however, results diminish due to the  chronic inflammatory response of the artery to the stent. Drug-coated balloon angioplasty has better results than plain angioplasty and is

competitive with bare metal nitinol stenting. Inadequate results of drug-coated balloon angioplasty due to dissection may require repair with some type of scaffolding. The goal in this setting is to minimize the metal footprint and repair the dissection as focally as possible. Bare metal stents below the knee have not proven to be more efficacious than balloon angioplasty and, therefore, have been used as a bailout in this situation.

WHICH LESIONS SHOULD BE STENTED? Although each specialist must decide the appropriate level of aggressiveness of stent placement, there are specific situations where stents are useful.

Postangioplasty dissection Dissection is the method by which balloon angioplasty functions. Dissections are locations along the treatment site where tissue has been torn away from the arterial wall and encroaches on the lumen. In the quest for safe lumen gain and a smooth and stable flow surface, it makes sense that leaving these behind is a gamble. Which ­dissections will lead to acute occlusion? Which dissections will form a nidus for recurrent stenosis? However, under existing paradigms for stent placement, coverage of every dissection with stents will lead to a substantial amount of metal burden that may not be required or may cause downstream negative effects with potential for in-stent restenosis. Because plaque fracture is the mechanism of angioplasty, some degree of dissection is almost always demonstrable. Dissections can be assessed angiographically and this assessment process is usually enhanced by obtaining more than one view of the treated vessel. IVUS provides more detail than angiography and permits the operator to evaluate and measure the residual lumen and to assess the post-treatment segment for mobile tissue flaps. Unfortunately, there is no good method of predicting how a dissection will behave (Figure  19.2). Dissections are also dynamic and may appear differently over time during the procedure and may respond to some extent to repeat but prolonged balloon inflation. Stent placement should be considered for any significant dissection after angioplasty, even if there is no gradient. Stents should be placed for

228  Stents, covered stents, stent–grafts

A

B

D

C

E

Fig. 19.2  Degrees of dissection after angioplasty. (A) An external iliac artery stenosis is treated with balloon angioplasty. (B) Angioplasty creates separations between the intima and media that are demonstrated on completion arteriography as small dissection flaps. (C) A more prominent dissection flap may not impede flow but does protrude into the lumen. Stent placement should be considered. (D) Dissections that impede flow, cause tissue to hang into the lumen, lengthen during the procedure, or extend into an adjacent nondiseased segment of artery should be stented. (E) The worst dissections may cause occlusion of the artery or severely diminish the flow, and usually involve multiple flaps. The angiographic picture is usually convoluted in appearance and direct visualization of the flow channel may not be possible.

any false channel or for any intimal flaps that impede flow, worsen during the procedure, or extend into a previously uninvolved segment of artery. Understanding which postangioplasty dissections require scaffolding is a work in progress. Nevertheless, the concept of “flow-limiting dissection” requires attention. It is often said that the operator need only respond to flow-limiting dissections. This is a term that is frequently used but never defined. Angiographic assessment is qualitative. Therefore, a flow-limiting dissection could be one that is visualized on angiography to slow down the blood flow. This is not quantitative

and is not reliable. The “flow” is dependent on the volume and pressure of the contrast administration and the inflow and runoff. Likewise, pressure measurement may be performed. This has the advantage of being quantitative; however, no one knows what level of gradient is clinically significant. The gradient will also be dependent on the quality of the runoff and whether the measuring catheter that crosses the lumen is affecting the pressure measurement. Note: if there is no runoff, there will be no gradient, no matter how significant the lesion. In addition, the moment the patient takes their first post-procedure step,

Residual stenosis after angioplasty  229

the gradient will change. If more than one lesion has been treated, the gradient is additionally difficult to interpret. Therefore,  measuring pressure is useful in some situations but is not likely to be the answer to how dissections should be managed. Angiographic and/or IVUS visualization are most commonly used at present.

RESIDUAL STENOSIS AFTER ANGIOPLASTY Residual stenosis can usually be resolved with stent placement. The concept of preventing recurrence by eliminating residual stenosis makes empiric sense. A 30% postangioplasty stenosis is used as a general threshold for continued intervention, although there is limited scientific justification for using this particular degree of stenosis. When residual stenosis is due to a severely calcified lesion, other methods may be required to treat it, such as scoring angioplasty or atherectomy. If stent placement is required, a woven nitinol stent might also be considered.

systemic  pressure. A pressure wire or low-profile catheter is placed across the lesion and pressure is measured at this location, distal to the lesion, until it becomes stable. If the proximal pressure can be measured at the exact same time and the curves are superimposed on the monitor, this is the best way to understand whether there is a gradient of 10  mmHg systolic or more. One challenge with measuring pressure through a catheter is that if there is a very small residual stenosis at the location of the lesion, the catheter used to measure pressure could also affect the pressure distal to the lesion. In this case a pressure wire would be helpful. It is common for the blood pressure to fluctuate during pressure measurement and care should be taken to ensure that it is stabilized when assessing the magnitude of gradient.

Recurrent stenosis after angioplasty Treating recurrence with stent placement after previous angioplasty is an empiric approach with reasonable results.

Pressure gradient

Occlusion

A pressure gradient (more than 10 mmHg systolic) after angioplasty usually indicates a significant residual stenosis or a dissection that is functioning as a baffle. The gradient threshold for treatment is somewhat arbitrary. It is possible that any pressure gradient is significant since pressure is measured at rest and patients’ lives are lived on the go. Some aspects of pressure measurement are discussed in the previous section. Pressure gradients are measured when it is unclear whether the reconstruction is hemodynamically effective. The most common place where this occurs is in the lower extremity vessels, mainly because other areas are more routinely treated with stents. Most of the time, a stent can be brought to full expansion and satisfy the operator on the basis of visual inspection indicating that no impediment to flow exists. If well performed, and angiography shows a residual stenosis of unclear hemodynamic significance, pressure can be measured. Pressure measurement can be helpful when considering stent placement. Systemic pressure can be obtained from an arterial line if one is already in place. Typically, the side arm of the sheath can be used to measure

Balloon angioplasty alone for occlusions has only fair results and these are improved with stent placement. Stent placement may make the procedure safer by stabilizing residual thrombus that could embolize from the lesion site. Stent placement in the treatment of iliac artery and SFA occlusions is widely accepted but not in the tibial arteries, where balloon angioplasty is used as a stand-alone procedure.

Embolizing lesion Stent placement at the site of an embolizing lesion is thought to trap the embologenic plaque and prevent further embolization. Because embolizing lesions are often soft, care must be taken during guidewire and catheter crossing. A covered stent or stent–graft of the appropriate size should also be considered in the treatment of an embolizing lesion, with the idea that the material in the lesion is trapped behind the material. The lesion must also be evaluated to assess whether it could be an aneurysm, especially if it is in the popliteal artery. The presence of an aneurysm may change the treatment plan.

230  Stents, covered stents, stent–grafts

Table 19.2  Which lesions should be stented? Indication

Rationale

Reality

Postangioplasty dissection

Prevents acute occlusion

Residual stenosis after angioplasty (>30%) Occlusion

Causes early failures and late recurrence

Makes angioplasty safer because dissection can be managed without emergency open surgery. More complex lesions can be treated with angioplasty. Which dissections need stents is not known. Most dissections should be treated if a smooth flow surface is desired Makes empiric sense. Mild residual stenosis may not cause harm. Moderate residual stenosis (>50%) can almost always be resolved with stent placement Better short- and long-term results with stents. Avoids open surgery in most patients with iliac occlusion or femoropopliteal occlusion Makes empiric sense since the initial angioplasty failed

Recurrence Long lesion Embolizing lesion

All lesions (primary stent placement)

Poor results with angioplasty alone Limited success of primary angioplasty Poor results with angioplasty alone Cages and compacts the embolic material Extends long-term results

More likely to result in a significant dissection after angioplasty of a longer length lesion Covered stent or stent–graft should be considered. Be certain it is not an aneurysm since that may change the treatment plan. Control outflow during procedure or use distal filter Looks great. Provides excellent opportunity to practice stent placement. Unclear if long-term results justify the up-front cost and complications

As experience is gained and new technological iterations are produced with stents, indications for their placement have been continuously modified and generally increased (Table 19.2). Other relative indications include a long lesion or a highly irregular, calcified plaque. The location of the intended angioplasty site also affects the likelihood of stent placement. Since most atherosclerotic renal artery lesions are aortic plaque that has spilled over into the artery, stent placement is usually necessary to resolve these stenoses. Stent placement appears to be safer than angioplasty alone at the carotid bifurcation, possibly because these are primarily embolizing lesions. Eventually, mesh covered stents may play a role in carotid stenting. Aortoiliac angioplasty is fairly durable without stents and stents can be used selectively with reasonable results, but the preponderance of more recent data, especially in patients with more severe disease morphology (TASC C and D), has been to support routine stent placement in this segment. Infrainguinal angioplasty is not as durable and stent placement offers some improvement in long-term results, especially in the femoral and popliteal arteries.

PLACEMENT TECHNIQUE FOR BALLOON-EXPANDABLE STENTS Considerations include selection of stent length and diameter, sheath size, and whether a single stent or multiple stents will be required. Diameter selection is an important decision in the placement of balloon-expandable stents. Stent size is selected based on the anticipated diameter of the reconstructed artery. If the selected stent is too small in diameter, it may not adhere well to the vessel wall after deployment and could migrate, even before it can be more completely expanded. In this case, the balloon must be rapidly exchanged for a larger one, which is used to expand the stent further. Placing the new balloon into the underexpanded stent is the key maneuver. If the stent is too large, it will overstretch the artery and may cause rupture or a dissection in the healthier vessel just beyond the end of the stent. If selective stent placement is performed, the inflated balloon profile from the initial angioplasty may be used to size the artery. When primary stent placement is performed, sometimes it is necessary to predilate the lesion with a plain

Placement technique for balloon-expandable stents  231

balloon to size the lesion and create enough space for the stent delivery catheter to be placed across the lesion. Balloon-expandable stents can be dilated a few millimeters larger than the intended specifications, but as the diameter increases, the length decreases. The shortest stent that will cover the lesion is typically placed. Longer balloon-expandable stents are available (up to 8 cm) but there are disadvantages due to the rigidity of these stents over longer distances. They do not conform well to any tortuosity or any change in vessel diameter along the length of the stent. Balloon-expandable stents have limitations in situations where long or diffuse lesions are encountered. Prior to placing a stent, the lesion length is assessed as well as the tortuosity and tapering effect present at the segment intended for stenting. Balloon-expandable stents are usually premounted in the factory. Hand crimping is sometimes required; for example, in the case of the largest balloon-expandable stent, which is used in the aortic neck after aortic stent–graft placement. If hand crimping is to be performed, the balloon chosen for deployment must be of either the same length or preferably longer than the stent. If the balloon is longer than the stent, the stent should be mounted so that its end is on either the proximal or distal radiopaque marker on the balloon; the stent’s location is thus known when it is time for deployment. Vigorous crimping with the thumb and forefinger secures the stent without bending it. The stent should not be able to slide on the balloon unless firm traction is applied. Test the adherence of the stent to the balloon, but do not slide the stent back and forth on the balloon because the sharp end of the stent can pierce the balloon. Mounting of the stent on the balloon is usually performed prior to advancing the sheath across the lesion so that the stent is ready for deployment. When advancing a catheter that has the stent mounted on it, support the stent at its trailing end as it is pushed through the sheath hemostatic valve so that the stent is not loosened on the balloon shaft. All the major endovascular companies make a puncture-resistant balloon that is designed for stent delivery. A medium Palmaz™ or Palmaz style stent requires a 6-Fr or 7-Fr sheath. Larger vessel stents, such as those used for large iliac arteries up to 12 mm, are placed through an 8-Fr or 9-Fr sheath. The largest, 5-cm length balloon-expandable stent is available for the infrarenal aorta and this stent has been used often

in bailout of Type I endoleaks during stent–graft repair of aortic aneurysms. It may have other niche uses in the aorta, such as for coarctation and other conditions. For many years, the general approach to ­balloon-expandable stent placement has been to pass the appropriate sheath and dilator combination through the lesion and proceed to stent placement (Figure  19.3). If the lesion has a residual lumen of less than the diameter of the sheath (for a 6-Fr sheath this is approximately 2.0 mm and for a 7-Fr sheath it is about 2.3 mm), the lesion should be predilated or the sheath and dilator will dotter the lesion. The sheath must be of adequate length to pass from the skin entry site to the lesion. A radiopaque tip on the sheath is useful so that it is clear where the sheath tip is located relative to the lesion. The dilator is removed and the sheath flushed. The sheath may stop or impede blood flow, since it occupies the remaining lumen at the site of the lesion. If there is any question about the exact location for stent placement, a repeat arteriogram should be obtained prior to placement. The balloon catheter, with the stent crimped into place, is passed over the guidewire and into the sheath. A cannula may be used to temporarily open the hemostatic valve on the sheath. However, the stent may also be passed through the hemostatic valve by hand. Grab the balloon–stent with a pincer grasp at the end of the stent that is farthest from the valve and push the balloon and stent through the valve. Using fluoroscopy, the balloon and stent are passed into the appropriate location. Check the balloon while it is still in the sheath using a magnified field of view to visualize the stent on the balloon and ensure it is still located where it was crimped on the balloon. The sheath is withdrawn, exposing the balloon and stent. Before deployment, it is important to make sure that the stent is still in the correct place on the balloon and that it is well positioned to cover the lesion. The balloon is then inflated to expand the stent. The stent should be slightly overdilated to embed its metal struts into the plaque. Another option for access, and one that is more commonly used at present, is to pass the tip of the sheath close to the lesion but not through it. If you are passing the tip close to the lesion, keep an eye on the unmarked dilator, as it may inadvertently encounter the lesion. The sheath tip is used as a platform for pushing, for easy arteriography, for stabilizing the back end of the stent after it is

232  Stents, covered stents, stent–grafts

A

B

C

D

E

F

Fig. 19.3  Placement technique for balloon-expandable stents. (A) The dilator and sheath are advanced through the lesion. (B) The dilator is removed, leaving the sheath across the stenosis. (C) The stent is premounted or is mounted on the balloon and crimped into place between the radiopaque markers. The balloon and stent are advanced into the sheath. (D) Using fluoroscopy, the stent is placed at the desired location within the lesion. (E) The sheath is withdrawn to expose the stent. (F) The balloon is inflated to deploy the stent.

Placement technique for balloon-expandable stents  233

deployed, and for helping to gather up the balloon after it has expanded the stent. Lower-profile, wellsecured, and premounted balloon-expandable stents have made it far less necessary to pass the sheath across the lesion in order to deliver the stent. Balloon-expandable stents expand initially to an hourglass shape with the proximal and distal ends of the balloon filling first and consequently flaring the proximal and distal ends of the stent. The middle portion of the stent fills out at the completion of balloon inflation. The proximal or distal end of the stent is sometimes only partially dilated into an oval shape, which is not always apparent on completion arteriography. The balloon is deflated after the stent has been fully deployed. The balloon may be advanced slightly and reinflated so that the proximal end of the stent is fully dilated. This maneuver may be repeated on the distal end of the stent. If there is a sense that the stent is loose in the lesion, either because it is underdilated or because it has migrated during deployment to an area that is slightly less narrow, take the next steps very deliberately. This occurrence is not too unusual in situations where a substantial poststenotic dilation of the vessel is present. This results in a substantial vessel diameter change over a short distance. The lesion may be one in which a balloon-expandable stent is required (e.g., innominate artery origin) but in which this type of stent is not well suited to a vessel taper. Advance the tip of the sheath up to the expanded end of the stent then catch the edge of the stent and support it so that it cannot move. This can usually be done right over the balloon catheter that delivered the stent prior to removing the balloon catheter. It is when removing the balloon catheter that the stent might begin to move. This is a common maneuver in renal stenting, which helps avoid a problem from getting out of hand. In addition, often after placement of a balloon-expandable stent the balloon wings will stick a bit, perhaps becoming caught under the tines of the stent. If this is the case, and more than a gentle pull does not solve it, use these steps. Perform aggressive aspiration, implosion level, negative pressure on the balloon. Support the stent by advancing the sheath as described earlier. Try rotating and/or advancing the balloon catheter gently for a few millimeters before withdrawing it. Sometimes, reinflating the balloon will loosen the balloon material; if this happens, these steps can be repeated.

Precise stent deployment is challenging. The stent may be difficult to visualize in larger individuals, especially if it is in a location with a lot of ventilatory motion, such as the visceral and renal arteries, where balloon-expandable stents are used quite often. A difference in location of a few ­millimeters may be the difference between a perfect placement and a misplaced stent. Road mapping is routinely used to help improve the precision of stent placement. Bony landmarks may be useful, especially the vertebral bodies or some identifiable vascular calcification. An external marker, such as a stent guide, might be helpful. This is an adherent, radiopaque measuring tape that can be placed on the patient parallel to the guidewire. Stent guides are particularly useful when treating longer lesions. Be aware that external markers are susceptible to parallax error if the field of view is modified. They are also in error if there is any change in the angle of view or any significant ventilatory motion. When external markers are used, recheck the lesion before deploying the stent. One method for precise placement of balloonexpandable stents is as follows. Position the image intensifier and set the field of view in a manner that provides the best view of the lesion. This view should include the tip of the sheath, the entire lesion length, and at least a few centimeters of outflow. If the lesion is too long to permit adequate magnification and the stent to be placed is just a portion of the reconstruction, magnify the location intended for the stent placement and place one stent at a time. Typically, there is one edge of the stent to be placed that will be the deciding factor as to its accuracy and precision. For example, provided the selected stent is long enough, when performing a stent of the renal artery orifice, the trailing end of the stent should protrude into the aorta by about 1 mm to ensure adequate treatment of any aortic plaque that is spilling over into the renal artery. This same general scenario repeats itself with other aortic branch orifice lesions with spillover plaque that is creating a circumferential napkin ring of atherosclerosis. Balloon-expandable stents work well in these scenarios and all of these situations involve deep imaging (in a body cavity) with significant ventilator motion. A smaller field of view, such as a 6-inch field, is often best since it provides magnification. Choose bony landmarks or place external markers. Perform arteriography. Once the image intensifier is positioned, do not move

234  Stents, covered stents, stent–grafts

it until after the stent is deployed. Perform a road map with the patient having taken a half breath in (not a deep sea diver breath that can change all the positions and the landmarks). Advance the stent into the lesion, have the patient take the exact same half breath in, and hold it as he/she had done during the angiographic run. During the breath hold, the road map should match up and the stent is deployed. After the stent is in place across the lesion, but before it is deployed, if there is any doubt about correct placement, puff contrast through the sheath to reconfirm the position or do another road map. After the stent is in the lesion, additional contrast runs may be performed, but the flow of contrast around the stent and through the lesion may be limited. The trailing end of the stent will be visualized, and this is often the most important part of the stent, especially in aortic branch origin lesions (e.g., ­innominate, subclavian, visceral, and renal arteries). Sometimes, this process is repeated a couple of times until the operator is satisfied with the position for stent placement. Have a contingency plan for what to do if the stent is placed too far one way or the other with respect to the lesion. Guidewire control must be maintained across the stent until the reconstruction is complete. The operator must be aware of and manage guidewire bias. In the case of branch artery origin lesions, traversal of the wire from the aorta into the branch is accompanied by wire bias, which will direct the wire toward one side of the lumen of the artery.

A

B

Anything that is passed over the wire, such as a subsequent balloon or the next stent, will tend to catch on the initial stent because of this wire bias. If additional stents are required, the sheath is advanced into the appropriate position. This can sometimes be done over the wire alone and sometimes it is necessary to advance the wire over the dilator. If the latter maneuver is selected, the operator must be careful to avoid damaging or dislodging anything with the dilator tip. If numerous overlapping stents are required, the distal stent is placed first and built proximally to create a “telescope” effect (Figure 19.4). If dilation to a larger diameter is required, the deployment balloon is exchanged. A balloon-expandable stent does not taper well but it can be dilated to a slightly larger size on one end if necessary to flare the end of the stent and attempt to match vessel size and taper. This is especially true of the newer balloon-expandable stents that are constructed of lighter and less rigid metal than the earlier generation of stainless steel stents. A completion arteriogram is obtained by placing the tip of the sheath at the distal end of the stent and injecting contrast so that it refluxes through the area of stent placement. Another option is to place a 4-Fr or 5-Fr straight catheter through the sheath, over the guidewire, and position the tip of the catheter at a location proximal to the stent. A  4-Fr or 5-Fr flush catheter may also be placed in the same manner and positioned upstream from the stent site.

C

Fig. 19.4  Telescope effect using balloon-expandable stents. (A) A long iliac artery stenosis requires more than one stent for coverage. (B) The distal stent is placed first. (C) The second stent overlaps the first and fits inside to create a telescope effect. This technique avoids a prominent metal edge protruding into the flow stream. The proximal end of the proximal or second stent may also be flared slightly with secondary balloon dilation.

Placement technique for self-expanding stents  235

PLACEMENT TECHNIQUE FOR SELF-EXPANDING STENTS Standard self-expanding nitinol stents must be oversized by 1–2 mm so that they exert continuous outward radial force at the site of deployment. Placing a stent that is too small in diameter must be avoided since these stents cannot be dilated beyond their nominal diameter in the same ­manner that a balloon-expandable stent can be overexpanded. If  there is doubt about the appropriate diameter stent to use, consider balloon angioplasty first with an evaluation of the inflated balloon profile. If still in doubt, use a stent that is a bit bigger in diameter. This is the opposite of balloon-expandable stents. Placement of a self-expanding stent is performed by withdrawing the covering catheter layer that encloses the stent on a prepackaged delivery catheter. The prepackaged stent delivery catheter is placed through a 5-Fr or 6-Fr sheath in most cases for peripheral arterial usage, as recommended by the manufacturer. The largest self-expanding stents used for aortic or venous applications may require an 8-Fr or 10-Fr sheath. Stent length choice varies significantly from one stent type to another. Self-expanding stents are manufactured in multiple lengths, from 20 to 250 mm in fully expanded form. Self-expanding nitinol stents, which are commonly used in the noncoronary arteries, usually do not shorten much on placement, although there are different designs. It makes sense to get used to a couple of products that you will routinely use in your practice and really understand the extent to which the trailing end of the stent tends to foreshorten. Self-expanding stents are generally simple to place and they adapt to tortuosity and manage longer lesions well. Woven nitinol stents (Supera® and Wallstent®) experience significant changes in length with deployment. The current application for the Supera® is in the femoropopliteal vessel segment, whereas the Wallstent® may be used in multiple arterial and venous vascular beds. The Supera® stent is deployed by pushing it out of its delivery catheter. The artery must be well prepared for the stent to reach its nominal diameter. The Supera® stent is highly crush resistant but exerts no chronic outward force. It is very effective at its nominal diameter, but is quite ineffective if it is deployed in a crimped manner. The ultimate length of the stent when deployed depends on the degree to which

the operator packs the stent into the lesion during deployment. The Wallstent® has quite a bit of chronic outward force and the final length of the stent depends on the final overall resting diameter. The constrained length of the Wallstent® (in the package) is longer than the deployed length and, after placement, is constrained by the artery. If the Wallstent® is opened on a tabletop and is completely unconstrained, it is even shorter. For example, a 10  ×  42 Wallstent® (10-mm diameter × 42-mm length) placed in a 9-mm iliac artery is 50–52 mm long after deployment. The Wallstent® in practice is not intended to be completely expanded, since it is oversized for the artery into which it is placed. The self-expanding stent catheter is removed from its package, flushed, wiped with heparin– saline solution and advanced over the guidewire (Figure 19.5). Because the delivery catheter and the stent are somewhat flexible, it can usually be passed over the aortic bifurcation or into branches without difficulty. Standard self-expanding nitinol stents are marked by radiopaque markers on their proximal and distal ends, which are observed using fluoroscopy. Woven nitinol stents typically do not have markers. To deploy a standard nitinol stent or a Wallstent®, the metal pushing rod is held steady and the valve body is withdrawn, which removes the covering membrane and ­permits the stent to expand on its own. The view on fluoroscopy is magnified and continuous because it is easy  to move the stent with minimal force and it makes sense to carefully adjust the stent location as  it begins to open. As the metal pushing rod is held stationary and the valve body is withdrawn, the proximal end of the stent begins to expand. As the nitinol warms up, it becomes more firm. The position of the stent is continually assessed as it is being deployed. A road map can be used to assist in placement. Self-expanding stents are more likely to be used for lesions in conduit arteries (e.g.,  iliac artery, SFA), which may be longer and have some degree of tortuosity (e.g., carotid artery, iliac artery). Self-expanding stents have the disadvantage that only the leading end of the stent, usually the end toward the tip of the catheter, can be placed with a high degree of accuracy. The back end, trailing end, or end of the stent that is closer to the hub end of the catheter will land with much less placement accuracy than the leading end of the stent. Somewhere in the course of self-expanding stent deployment, but

236  Stents, covered stents, stent–grafts

A

B

C

D

Fig. 19.5  Placement technique for self-expanding stents. (A) The guidewire is placed across the lesion. (B) The stent delivery catheter is placed over the guidewire so that the proximal marker on the stent delivery catheter is proximal to the lesion. The metal push rod is held stationary while the valve body is slowly withdrawn. (C) The position of the stent is continuously monitored during deployment. A magnified view may help perfectly place the proximal end of the stent. As the stent is about to open, it can be withdrawn slightly to reposition it, but not advanced. As the valve body is withdrawn along the length of the pushing rod, the covering sheath or membrane that constrains the stent is removed and the stent spontaneously expands. (D) After stent ­deployment, the delivery catheter is removed. Poststent placement balloon angioplasty is performed.

Placement technique for covered stents  237

before there is full engagement of the stent with the artery wall, the stent can be moved and its position readjusted. When the leading end of the stent starts to open it “blossoms”. Once that blossom becomes big enough to touch the wall of the artery, the stent cannot be advanced, but usually can still be withdrawn. Most self-expanding nitinol stents can deploy about 15% to 20% of their length, or 1 cm (whichever is less), and it still be possible to withdraw the whole stent to readjust its ­position. If there is too much adherence of the stent to the wall already in play, when the catheter is withdrawn, the stent just hugs and hangs on to the wall and the stent deploys. If the stent is moved after there is a lot of contact between the artery wall and the stent, there is a risk that the end of the stent will be mangled. There is a reconstrainable Wallstent® that can be covered up again by its covering membrane, provided the release process has stopped short of a certain point that is marked on the delivery catheter. The stent can then be moved to a different place and deployed. The Wallstent® is a closed cell structure. This permits a relatively smooth outer surface without any “V”-shaped stent joints extruding beyond the profile of the open or partially open stent. This facilitates recovery of the outer surface of the stent if desired. This recapturability will probably not be possible with open cell nitinol self-expanding stents in the near future. The design allows the stent to spring all the way open when one end is deployed and one end is still constrained in the delivery catheter. In other words, the open cell stents contour well and they are able to go from a very small diameter to a large diameter over a very short longitudinal distance. This property is needed for the management of tortuous or tapered arteries, but it also creates rough edges where stent joints are under stress and protrude into the lumen. Most of the self-expanding stents deploy in a similar manner to each other: holding a pushing rod in a stationary position while withdrawing the covering membrane and allowing the stent to expand. Some have ratcheted handles or turnwheel knobs to activate for better control, possibly accuracy, but it is the same underlying mechanism. Take the slack out of the guidewire and catheter. Be aware that any withdrawal of the catheter for placement accuracy will also tend to pull the sheath out. Built-up energy in the stent delivery

catheter, when released, tends to make the stent pop forward a bit (toward the tip end) during deployment. After stent deployment, the delivery catheter is removed and balloon angioplasty of the length of the stent is performed, especially in sections where there is residual crimping of the stent by the lesion. It is  sometimes difficult to assess whether the stent is fully expanded. Keep the balloon within the stent if injury is to be avoided to neighboring artery segments. When balloon angioplasty is to be used within the Wallstent®, the central part of the stent is dilated first. The ends of the stent are dilated last because the tines of the stent may rupture the balloon. The guidewire is maintained across the stented segment until after satisfactory completion studies are performed. Completion arteriography is performed in the same manner as with balloonexpandable stents. If guidewire control of the stent is relinquished prematurely, advance a J-tip or very floppy-tip guidewire back through the stent using a small field of view for magnification. This is done to avoid passing the guidewire through the struts of the stent. This is easy to do, especially prior to postdeployment balloon angioplasty. If you have to cross a fresh stent and you are not sure if you are under its tines, pass a straight or simple curve catheter over the guidewire. If the guidewire goes under one of the stent struts, the catheter will hang up instead of passing freely.

PLACEMENT TECHNIQUE FOR COVERED STENTS Choosing the appropriate stent diameter is important no matter what kind of stent is planned, but with self-expanding covered stents the diameter choice is even more important. This is because significant oversizing of the stent results in placement of a larger amount of material, which may overwhelm the available lumen. In addition, when treating longer segments with self-expanding stents, there may be some overlap between different stents. In the overlapped segment the amount of material is even larger. When there is a change in diameter or tapering of the artery, typically the smallest diameter covered stents are placed first and the larger diameter self-expanding covered stents are placed subsequently. This permits the development of a friction seal. When treating occlusive disease, consider minimal overlap of the

238  Stents, covered stents, stent–grafts

covered stents in order to prevent build-up of material. When treating aneurysmal disease, such as in the popliteal artery, more overlap will be required to prevent the stents from becoming dislodged or disjointed. When selecting a balloon-expandable covered stent, the stent is sized to the artery. In that setting the operator has the luxury of a slight overexpansion of the balloon if additional diameter is required. There is typically a larger sheath required for covered stents than for bare metal stents. In order to make more room for delivery through the sheath, many covered stents are delivered over smaller diameter guidewires, such as 0.018-inch diameter wires. The deliverability is partly diminished with covered stents due to the larger amount of material that usually fits very tightly within the sheath. After the constrained covered stent has passed through the sheath, the outside surface of the covered stent is typically irregular, and the device itself on the catheter is usually slightly bulkier than a bare metal stent. All these aspects affect the ability to deliver the covered stent to its desired location. If the covered stent is being delivered into a tortuous area, such as when being used as a renal or visceral snorkel, it will likely not pass bareback. In this case, the sheath is placed where the covered stent is desired, the stent is advanced into location, and then the sheath is withdrawn. Once the device is in the appropriate location, the placement depends to some extent on the type of covered stent. For balloon-expandable covered stents, the delivery is very similar to other balloon-expandable stents. The device is placed exactly where desired and the balloon is inflated. There is typically minimal foreshortening. With self-expanding covered stents, there may be some adjustment of position during deployment of the leading edge of the stent, and there is usually minimal foreshortening. After placement of self-expanding covered stents, the operator performs aggressive balloon angioplasty of the stent to make sure it is fully expanded. The outward radial force is typically low and the potential for the lumen to be compromised is increased. With balloon-expandable covered stands, additional balloon dilation is usually not required, but sometimes, depending on the location, the operator decides to dilate the end of the stent to flare it slightly.

Strategy: What to consider when selecting a stent 1. Can you visualize the stent in this position? 2 . What are the length and diameter requirements of the diseased segment? 3. What is the location of the lesion and what type of lesion is it? 4. Are there delivery restrictions posed by diseased access arteries, sheath size, vessel tortuosity, working room, or distance to the lesion? 5. Can the number of required stents be minimized? 6. Is the stent in your inventory?

WHICH STENT FOR WHICH LESION? Table  19.3 offers a practical comparison of the working properties of different stent categories. In general, orifice lesions and those that are heavily calcified are best treated with balloon-expandable stents. Lesions located in flexible or tortuous arteries, or that are more than several centimeters in length, are usually treated with self-expanding stents. Either balloon-expanding or self-­expanding stents may be used in the aorta (Table 19.4). Short focal lesions may be treated with balloon-expandable stents. Placement is precise and the single stent is less expensive. Self-expanding stents are well suited to longer aortic lesions (longer than 2–3 cm). Placement of a single longer self-expanding stent is usually simpler, faster, and less expensive than placing multiple balloon-expandable stents. Just be careful to ensure that the trailing end of the stent clears the aortic bifurcation and opens fully within the aorta. The other advantage of self-expanding stents in the aorta is when there is a heavily calcified, shelf-like, or iceberg-like lesion, the stent can be laid in and the lumen gradually enlarged with successively enlarging angioplasty balloons. This is done to avoid rupture. Lesions in the aortic bifurcation are treated by “raising” the aortic flow divider with balloonexpandable stents. Precise, “kissing,” and sideto-side placement is possible with self-expanding stents, but is more challenging and may not be adequate to manage heavily calcified plaque at the aortic bifurcation. Aortic bifurcation plaque usually extends into the common iliac artery orifices. Self-expanding stents do not have as much hoop

Approximately 15 cm

Significant; depends on how tightly the stent is packed High

>9.4 cm

Shortens by more than 30% of constrained length Low

25 cm

Less than 8%, does not depend on final diameter Low to medium

Shortens by 5% to 25%, depending on final diameter High

None

None

Length changes during placement Hoop strength

Flexibility

Contourability

High

High

Moderate

Moderate

Poor; does not contour to diameter changes

High

Self-expanding

>5 cm

Self-expanding

Maximum length

Self-expanding

Woven nitinol (Supera®)

Balloonexpandable

Woven nitinol (Wallstent®)

Method of expansion

Self-expanding (nitinol)

Balloonexpandable

Working quality

(Continued)

Requirement for balloon expansion to deploy makes balloon-expandable stent placement a little more complicated, but self-expanding stents always require postexpansion balloon dilation Balloon-expandable stent length limited; lesions more than 3 or 4 cm need more than one stent; adds complexity, time, and cost to the case. Self-expanding stents provide longer length Final resting Wallstent® length can be difficult to predict; nitinol stents have minimal shortening Balloon-expandable stent is a better choice for orifice lesions and heavily calcified arteries Self-expanding stents are better choices for tortuous or tapered arteries

Advice

Table 19.3  Practical stent comparison: working qualities of balloon-expandable, self-expanding, and woven nitinol stents

Which stent for which lesion?  239

Balloonexpandable

>24 mm

Precise

6–9 Fr

Sharp edges; cannot be clamped; can tear balloon

Working quality

Maximum diameter

Precision of placement

Delivery sheath

Biohazard

6-Fr or 7-Fr

Will not expand to nominal diameter if lumen is not adequate

Loose wire ends are sharp; can be clamped in emergency

No sharp edges; can be clamped in emergency

Only somewhat precise and only on one end

7 mm

Woven nitinol (Supera®)

6–9 Fr

Precise only on one end

24 mm

Woven nitinol (Wallstent®)

6–8 Fr

Precise on one end

14 mm

Self-expanding (nitinol)

Self-expanding stents a better choice for vessels >12 mm in diameter; balloon-expandable stents can be pushed to larger sizes, but with severe foreshortening Proximal end (first end to be deployed) of self-expanding stent can be placed precisely and moved a bit prior to full deployment; location of second/distal end of stent is not precise Balloon-expandable stent requires a long sheath to be placed through the lesion, which adds risk of instrumenting lesion and creates problems for remote delivery. Self-expanding stents are on delivery catheters In an emergency, self-expanding stents can be clamped with a shodded clamp

Advice

Table 19.3 (Continued)  Practical stent comparison: working qualities of balloon-expandable, self-expanding, and woven nitinol stents

240  Stents, covered stents, stent–grafts

How to select the best stent for the job  241

Table 19.4  Some examples of which stent to use Angioplasty site

Lesion type

Stent to use

Reason

Aorta

Focal lesion Bulky lesion Long (>2–3 cm) Iliac origin Focal Tortuous Long (especially external iliac) Long Across joint Focal, short Heavily calcified Orifice Body of artery Tortuous Orifice

Balloon-expandable Self-expanding Self-expanding Balloon-expandable Balloon-expandable Self-expanding Self-expanding

Length match Gradual expansion, avoid rupture Fewer stents required Hoop strength Length match; simple Flexible Fewer stents required; handles tortuosity well Fewer stents required Flexible Better patency Supera® hoop strength Hoop strength, rigid

Aortic bifurcation Iliac

Superior femoral/ popliteal

Renal Subclavian

Self-expanding Self-expanding Self-expanding Woven nitinol Balloon-expandable Either Self-expanding Balloon-expandable

strength, which is desirable for the aortic bifurcation and other orifice lesions. Routine common and external iliac artery lesions may be treated with either self-expanding or balloon-expandable stents. Focal lesions are treated with balloon-expandable stents and selfexpanding stents are used for longer lesions and those located in tortuous arteries or arteries with significant taper. Distal iliac artery lesions that are close to the groin should be treated with selfexpanding stents to maintain flexibility. Self-expanding stents are better for stenting in flexible arteries, such as the superficial femoral, popliteal, and distal subclavian arteries. Lesions in an aortic branch orifice, such as the proximal innominate, common carotid, subclavian, visceral, or renal artery, are best treated with balloonexpandable stents. The combination of placement accuracy and hoop strength is better in this setting.

HOW TO SELECT THE BEST STENT FOR THE JOB Although there are multiple considerations when selecting a stent for a given case, there is substantial overlap in the capabilities of the various stents. Most specialists develop a short list of a couple of favorites in each stent category, balloon-­expandable and self-expanding, in each vascular bed. One trend of

Flexible Hoop strength

note is that self-expanding stents are being used more widely than before. They are becoming more versatile, better engineered, provide more choices, and there is better data on results. What follows is a discussion of some of the issues that drive stent preferences in clinical practice. Most practices have at least some restriction on the variety of stents stocked and the number of different stent diameters and lengths available. Specialists with a limited inventory will ask the question sooner, but everyone must face the availability issue at some point. Work with what is available or plan ahead well enough so that specific items are anticipated and ordered. The development of various sizes, lengths, designs, profiles, and qualities of stents has been significant over the past few years. The single most important thing to do when selecting a stent is to visualize the stent in the intended location. Will it expand to oppose the wall of the artery? Can it handle the tortuosity and/or diameter changes? Does it have the hoop strength to stand up to the amount of calcification present in the lesion? Will one end of the stent be floating free in a segment of poststenotic dilation? Will it cover the segment of artery most in need of treatment? Can the stent be passed safely to the target site? Will it cover or impinge on an important branch and, if so, is that acceptable? Can the

242  Stents, covered stents, stent–grafts

lesion be treated with a single stent or will multiple implants be required? The length and diameter requirements of the lesion must be taken together with the type and location of the lesion in order to come up with a stent choice. Lesion type and location were discussed in an earlier section. It is not always apparent how long a length of artery should be stented if there is mild or even moderate disease juxtaposed to the lesion. The operator must make an arbitrary decision in many cases. The diameter may be sized the same way as for balloon angioplasty, but the consequences of a bad guess are greater. If a balloon-expandable stent is undersized, it may not be securely adherent to the artery. If it is oversized too much, the artery may be injured. One method of dealing with this dilemma is to undersize the balloon-expandable stent just slightly. Deploy the stent so that it is held in place by the newly dilated lesion. Then dilate the stent again to the desired size using a larger balloon if necessary. The diameter choices for self-expanding stents provide more leeway since the stents are oversized from 1 to 3 mm. Nevertheless, if too small a stent is used, it may become free-floating. Required stent lengths can be challenging. All external marking methods have some degree of parallax. Finally, delivery restrictions may be posed by diseased access arteries, the sheath size of the selected stent, vessel tortuosity, adequacy of working room, a long distance to the lesion, or branch points between the access point and the lesion. The risk of puncture site thrombosis increases when a large sheath is passed through a diseased common femoral artery. Sheath size may influence the choice of stent, since relatively larger diameter self-expanding stents may be placed through 6-Fr sheaths. Vessel tortuosity or a branch point on the way to the lesion can be overcome with a guiding access sheath of the appropriate length. Occasionally, a more flexible stent is required to make these turns (e.g., over a very narrowly angled aortic bifurcation) and a self-expanding stent is used instead of a balloon-expandable stent. The distance to the lesion is an important variable. Balloon-expandable stents must be mounted on a balloon with an adequate shaft length, and self-expanding stents must be delivered on a delivery catheter of adequate length. Both balloon-expandable and self-expanding stents are generally available on two different lengths of catheter, either 80 cm or 120 cm. If an 80-cm shaft

is opened when a longer shaft is required, it will have to be discarded. These challenges can usually be solved by using the balloon shaft length to estimate distance if the lesion was dilated prior to stent placement. If not, a standard arteriographic catheter with a bright tip may be placed over the guidewire and advanced close to the lesion and used to estimate the length from the access to the lesion. If the distance from the access to the lesion is farther, there are some devices up to 150 cm in length, but care must be taken to ensure that these are available. If not, or if the longest devices are inadequate, the operator must make a plan for an alternative access closer to the treatment site.

TRICKS OF THE TRADE Raising the flow divider with kissing stents A bifurcation can be reconstructed by modifying the flow divider with kissing stents. Two stents are placed simultaneously with the leading edge of each stent abutting the other at a point proximal to the location of the native flow divider. The need for kissing stents arises most commonly at the aortic bifurcation (see Chapter 23 for a detailed discussion of this technique). The atherosclerotic disease that occurs at the aortic bifurcation tends to be extensive and circumferential. With kissing stents, the aortic bifurcation can be reconstructed. There is also a technique for reconstruction of the aortic bifurcation in which a covered stent is placed in the infrarenal aorta and covered balloon-­ expandable stents are placed at the aortic bifurcation in the fashion of kissing stents. This provides a completely covered reconstruction of the aortic bifurcation. After any of these techniques for raising the flow divider are performed, it is usually not possible to deliver endovascular devices up-andover the aortic bifurcation.

Tapering a stent The various self-expanding stents tend to taper naturally with diminishing distal arterial diameter. Standard open cell nitinol stents should be dilated with the appropriately sized balloon. All of the selfexpanding nitinol stents exhibit variable degrees of foreshortening. Because of this, balloon dilation should be performed first at the location along the

Tricks of the trade  243

A

C

B

D

E

Fig. 19.6  Tapering a self-expanding stent. (A) The guidewire is passed through an iliac artery stenosis. (B) The self-expanding stent is deployed across the lesion. (C) The self-expanding stent tends to taper naturally with decreasing distal arterial diameter. (D) The distal end of the stent is ballooned to the diameter appropriate for the external iliac artery. (E) Angioplasty is performed in the larger proximal end of the stent, which lies in the common iliac artery, using a slightly larger balloon.

stent where some shortening would be least desirable (Figure 19.6). Once the final diameter of the stent is fixed in this location, dilation of other segments of the stent with the appropriately sized balloon is performed. The Wallstent® tends to shorten quite a bit with expansion. The very end is dilated last since it may lead to rupture of the balloon. Woven nitinol stents (Supera®) cannot taper and cannot be manipulated much with balloon dilation. The shorter, more rigid balloon-expanding stents can also be tapered, but to a much lesser degree (1–2 mm maximum). One end of the stent is selectively dilated using only the shoulder of the balloon (Figure 19.7). The operator may also consider flaring the proximal end of a balloonexpandable stent at the origin of a renal or visceral artery. In this case, only a very short segment of balloon shoulder is placed in the stent.

Moving a self-expanding stent To varying degrees, self-expanding stents can be moved a bit to adjust deployment position. The delivery catheter can be withdrawn or pulled back but not advanced forward after beginning partial deployment. The entire deployment catheter apparatus must be withdrawn in a retracted position to move the stent (Figure 19.8). Most standard nitinol stents tend to move a little during initiation of deployment. Moving the stent can be helpful in achieving very precise placement of its proximal end. It is not possible to move a stent after it has been deployed. Under magnified fluoroscopy, the stent delivery catheter tip is carefully observed. When the proximal end of the stent begins to expand and change shape, this is the opportunity to adjust its position. If too much of the stent is

244  Stents, covered stents, stent–grafts

A

B

D

C

E

F

Fig. 19.7  Tapering a balloon-expandable stent. (A) The guidewire is passed through an iliac artery stenosis. (B) The sheath and dilator are advanced through the lesion. (C) The balloon and mounted stent are advanced through the lesion and the sheath is withdrawn. (D) The balloon-expandable stent is deployed to a size appropriate to the diameter of the external iliac artery. (E) A larger diameter angioplasty balloon is used to enlarge the proximal end of the stent. (F) A slight taper of the stent is created across the iliac bifurcation. Balloon-expandable stents can only be made to taper in a minimal way, but by flaring the end of the stent, it can often be molded to the appropriate shape.

A

B

C

D

Fig. 19.8  Moving a self-expanding stent. (A) The guidewire is placed across the lesion. (B) Stent deployment is initiated more proximally than its final intended location. (C) The entire delivery apparatus is withdrawn to move the proximal partially expanded end of the stent into the intended location. Stent systems vary in terms of how much leeway the operator has to do this. (D) After correct positioning, deployment continues.

Tricks of the trade  245

released from the catheter and it is strongly in contact with the arterial wall, do not adjust its position at this point. Dragging the stent after it has fully engaged the vessel may cause the structure at the end of the stent to be mangled. If the stent has not been deployed in the correct location, the best solution is to place another stent at the desired location.

Crossing a stent Once a stent has been deployed, the guidewire position across the stent is not relinquished until the procedure is completed. If the guidewire position is lost, or if a repeat study is necessary in a patient who has a stent, it is best to cross the stent using a J-tip or floppy tip guidewire (Figure 19.9). The elbow of the J-tip guidewire is less likely to pass through the struts of the stent. If there is any doubt about the position of the guidewire, it should be withdrawn and a repeat crossing performed. The J-tip guidewire should be able to twirl and bob freely within the lumen of the stent.

After the guidewire is across the stent, the intraluminal position can be checked using a 5-Fr straight angiographic catheter passed over the wire. Any resistance as the catheter passes through the stent indicates a false passage, probably between the struts of the stent. Use a small field view for magnification and oblique views if needed. Passing the guidewire through the interstices of the stent will lead to complications if it is not recognized that this has occurred.

Placement of a balloon-expandable stent without a crossing sheath Placement of balloon-expandable stents was designed to be performed with a sheath across the target site. This permits protection of the stent from migrating on the delivery catheter in response to friction. Premounted stents are reliable and have largely changed this approach to one in which the stent delivery catheter is passed without sheath coverage. In certain situations, placement of the sheath into the desired location across the lesion is challenging, especially with highly tortuous approach arteries or when the sizable sheath hangs up on the lesion itself (Figure 19.10). One option is to advance the premounted stent over the guidewire and through the lesion without a sheath for protection. Use a premounted stent that comes in a package with the stent already sealed onto the balloon. If treating a critical stenosis, predilate the lesion so that the stent will pass through without being dislodged from the balloon.

Technique: Bailout maneuvers for balloon-expandable stents

A

B

Fig. 19.9  Crossing a stent. (A) After deployment, there are many potential routes of false ­passage through the struts of the stent. (B) Passage through the struts is usually avoided with a J-tip guidewire or an atraumatic guidewire with the tip looped on itself.

1. Sheath will not advance across the lesion. Dilate the lesion and then advance again. Consider using a stiffer guidewire. 2 . Balloon with stent will not pass through the sheath. The sheath may have kinked (Figure 19.11). Visualize under fluoroscopy. Consider pulling the kinked part of the sheath back into a straighter segment of the artery and try again to pass the balloon and stent. If unsuccessful, pull out the balloon and stent with the sheath but leave the guidewire in place. Change the sheath and start again. Consider using a self-expanding stent for tortuous arteries. (Predilate the lesion; use a larger sheath and stiffer wire.)

246  Stents, covered stents, stent–grafts

A

B

C

D

Fig. 19.10  Placement of a balloon-expandable stent without crossing the lesion with a sheath. (A) The guidewire is placed across a lesion at the origin of the subclavian artery. (B) A transbrachial sheath is placed but the artery is too tortuous to permit safe passage of the sheath through the lesion. (C) The angioplasty balloon with premounted stent is passed beyond the sheath and through the lesion. (D) The stent is deployed. Because the process of premounting of balloon-expandable stents has improved, the concern about the stent coming off the balloon before full deployment is decreased, but the operator should be aware that this could still occur.

D

A

B

C

Fig. 19.11  Kinked sheath preventing passage of a stent. (A) The guidewire is passed through a lesion in a tortuous iliac artery. (B) The sheath and dilator are advanced through the lesion in preparation for stent placement. (C) After the dilator is removed, the sheath becomes kinked. (D) The balloon with mounted stent cannot pass because the sheath is kinked. If there is too much friction or a hard stop while passing a stent delivery catheter, use fluoroscopy to evaluate the sheath.

Tricks of the trade  247

3. Loose stent inside the sheath. Pull out the sheath, balloon catheter, and stent. Leave the guidewire, if possible. Use fluoroscopy to ensure that the stent comes out with the sheath. If the stent is on the shaft of the catheter, the balloon can be inflated just slightly in order to keep the stent on the catheter while the catheter is being removed. 4. Loose stent on the catheter shaft beyond the end of the sheath. Pull the balloon back into the stent using the tip of the sheath to pin the stent. Pull the stent back into the sheath, if possible. Use a partially inflated balloon to pull the stent and remove the sheath. If the stent cannot be pulled back into the sheath, pin the back end of the stent with the tip of the sheath and deploy in a neutral location (Figure 19.12). 5. Loose stent on the guidewire. Advance a small balloon into the stent to flare the end and stabilize it. Deploy in a neutral location (Figure 19.13).

A

B Fig. 19.12  Balloonexpandable stent loose on the catheter shaft. (A) A stent becomes dislodged from its position on the balloon catheter during passage through the sheath. (B) An attempt is made to pull the stent back into the sheath. (C) The entire sheath is removed with the stent inside. (D) If the stent cannot be dragged back into the sheath, the end of the stent is pinned with the tip of the sheath. (E) The balloon is pulled back into the stent to reload. (F) The sheath is withdrawn and the newly remounted stent deployed in a neutral location.

C

D

E

F

6. Stent embolizes. Use a long sheath and cardiac biopsy forceps or a loop snare to pull or push the stent into a favorable location where it can be abandoned (internal iliac, deep femoral, or tibial arteries) or retrieved surgically (common femoral artery). 7. Balloon ruptures during deployment of balloon-expandable stent. Perform high-pressure, hand-powered balloon inflation with saline solution in an attempt to overwhelm the hole in the leaky balloon (Figure 19.14). Advance the sheath to pin the stent so that it is not withdrawn with the balloon. Rotate and remove the ruptured balloon, cross the stent with another balloon, and inflate. 8. Dissection at the end of the stent. Place a new overlapping stent (Figure 19.15). 9. Stent tilts. Some balloon-expandable stents are too rigid for tortuous arteries. Self-expanding stents are often a better choice (Figure 19.16). Place another stent to straighten the curve and create a smooth surface at the end of the stent.

248  Stents, covered stents, stent–grafts

Fig. 19.13  Balloon-expandable stent loose on the guidewire. This is a more severe problem than ­having a stent loose on the catheter shaft. In this situation, the delivery balloon usually cannot be used as a tool to help solve the problem. If the stent is not securely mounted on the balloon, the stent may shoot forward off the balloon during inflation. The end of the stent may be partially flared and dangling on the guidewire. (A) The guidewire is advanced to allow room to maneuver. (B) A smaller, lower profile ­balloon is exchanged. (C) One end of the stent is flared further. This provides space to permit an attempt to place the appropriately sized balloon for deployment of the stent. (D) The appropriately sized balloon is substituted. (E) The stent is deployed in a neutral position. Stents deployed in a neutral position in this manner are usually well tolerated by the patient and do not cause subsequent problems.

A

B

C

D

E

A

B

C

Fig. 19.14  Balloon rupturing during deployment of a balloon-expandable stent. (A) The angioplasty balloon ruptures on the sharp edge of the stent during deployment. (B) High-pressure, hand-powered inflation attempts to overwhelm the leak in the balloon. Often, but not always, the ends of the stent flare enough to prevent immediate migration using this maneuver. (C) A new balloon is placed to complete the deployment.

Tricks of the trade  249

Fig. 19.15  Dissection at the end of the stent. (A) A guidewire is placed across the lesion. (B) A stent is placed but a dissection flap develops at the interface between the lesion and the adjacent nondiseased segment. This may occur in situations in which the stent does not quite cover the entire diseased segment or in which aggressive postdilation was performed at the edge of the stent and extending into the adjoining segment of artery. (C) Another stent is advanced into position with a slight overlap of the previously placed stent. (D) Stent placement repairs the dissection.

A

B

C

D

Fig. 19.16  Tilted balloon-expandable stent. Balloon-expandable stent placement usually reflects the presence of any significant wire bias. If there is a tortuous path for the wire, when the stent is placed, there is a slight tilt reflecting this dynamic. Occasionally, this is a problem; one end of the stent may not be opposed to the artery wall in its intended manner. (A) A guidewire is passed through a stenosis along a curve in the artery. (B) A stent is placed across the lesion. The combination of the curvature of the artery and the location of the lesion prevents the edge of the stent from being well opposed to the arterial wall. (C) Balloon angioplasty of the protruding end of the stent is performed. (D) If angioplasty is not successful, another stent is placed to force the edge of the stent against the wall.

A

10. Balloon sticks in the expanded stent. Material is caught in the struts. Do not yank because the material may fragment. Rotate the catheter, reinflate, push gently to advance, and then withdraw. If that does not work, advance the sheath so that its tip can at the same time hold the stent in place and act as a funneling device to accept the torn balloon. 1 1. Stent requires surgical removal. If the stent is expanded but not deployed, retrieving the stent may be a challenge that requires open surgery. An artery cannot be occluded with a clamp at the location of a stent. The ends of the stent are sharp!

12. Avoid deployment of stent in the sheath. Be sure that the tip of the sheath has been withdrawn adequately to avoid capturing the end of the stent.

B

C

D

Technique: Bailout maneuvers for self-expanding stents 1. End of the stent is not fully expanded. The hoop strength of the self-expanding stent may not be adequate to compress the lesion. Dilate the body of the stent to make sure it is properly seeded, and then dilate the ends (Figure 19.17).

250  Stents, covered stents, stent–grafts

A

B

C Fig. 19.17  End of the self-expanding stent is not expanded. (A) A self-expanding stent is placed but there is significant residual stenosis and it is also causing one end of the stent to not fully expand to meet the vessel wall. (B) A balloon catheter is passed into the segment of residual stenosis. (C) Angioplasty is performed aggressively along the stent, first in the area of residual stenosis and then at the end of the stent.

A

B

Fig. 19.18  Self-expanding stent extends into an undesired location. (A) A self-expanding nitinol stent is placed in the external iliac artery but extends into the common femoral artery. (B) Slight overdilation of the proximal end and the body of the stent with angioplasty may cause the stent to shorten a very small amount. Slight traction on the balloon placed into the body of the stent may also help to move the distal end of the stent a ­millimeter more proximally.

2 . Stent is undersized for the given artery. The chosen stent is too small. There is no good solution. 3. Stent extends into an undesired location. It is worth trying to dilate the opposite end of the stent; this sometimes leads to foreshortening of the stent so that it encroaches a little less on the segment of concern (Figure 19.18). This works well with a Wallstent®. Other types of self-expanding stents can sometimes be moved a very short distance by inflating a balloon and pulling gently on the catheter. 4 . Stent location is inaccurate. The only way to avoid this is to deploy the leading end of the stent at the location of highest interest. This portion of the deployment process has the greatest precision (Figure 19.19). The finished location of the trailing end of the stent is much less accurate in self-expanding systems. 5. The end of the stent extends into the hemostatic introducer sheath. The stent will not deploy. Sheaths with radiopaque markers are used fairly routinely. If the tip of the sheath does not have a radiopaque marker, it may be difficult to visualize. Puff contrast through the sheath. Pull the sheath back slightly while holding the stent delivery catheter in place to release the crimped stent (Figure 19.20). 6. Stent collapses in its mid-section. Repeat the angioplasty. If that is unsuccessful, place a balloon-expandable stent inside the selfexpanding stent (Figure 19.21). This most often occurs in the setting of severe calcification and inadequate vessel preparation. 7. Balloon breaks on the end of the stent. Balloon the end of the stent last or use a thicker polymer balloon. 8. Artery with stent in it requires clamping. Use shodded arterial clamp. The artery can be clamped enough to occlude inflow but may damage the stent. Balloon occlusion can also be obtained using a standard angioplasty balloon of 4 cm in length and the appropriate diameter. 9. Stent requires surgical removal. It is rare for a stent to require removal. When a self-­ expanding stent is removed, it usually comes out in pieces as the structural integrity of the stent cannot stand up to the process.

Tricks of the trade  251

A

B

C

D

E

Fig. 19.19  Self-expanding stent location is inaccurate. Deployment should be initiated at the end where the most accuracy is required. Since self-expanding stents deploy in the direction of the tip end to the hub end, this should be taken into account when choosing a stent or choosing the direction from which it will be deployed. (A) An external iliac artery lesion can be approached either antegrade or retrograde. (B) Self-expanding stent placement through a retrograde approach ensures precise placement of the proximal end of the stent. (C) The final length of the stent may be difficult to predict. The distal end of the stent extends into undiseased common femoral artery. (D) Selfexpanding stent placement through an antegrade approach places the distal end of the stent first because the working room between the inguinal ligament and the lesion is limited. (E) The excess length of the upper end of the stent extends into the proximal external iliac artery. Fig. 19.20  Partially deployed self-expanding stent extends into the delivery sheath. (A) Stent deployment begins but the second end of the stent cannot be deployed because the tip of the access sheath impinges on the stent. This occurs when the working room between the deployment site and the arterial entry site is limited. (B) The hemostatic access sheath is withdrawn enough to permit the stent to expand. A sheath with a radiopaque tip may help avoid this problem. When withdrawing the sheath, hold the stent delivery catheter firmly and provide back pressure. If there is a substantial length of stent within the sheath, this maneuver can cause undesirable elongation of the stent.

A

B

252  Stents, covered stents, stent–grafts

Arterial dissection A

B

If acute arterial dissection occurs in juxtaposition to a stent, an additional stent is placed in this location (Figure 19.15). The lead point for arterial dissection associated with stent placement is usually within a centimeter of the end of the stent. A  stent is placed in this segment even if it is not clear exactly where the lead point of the dissection is located.

Arterial occlusion C

The stented site may occlude as a result of arterial dissection or placement of a stent that is not fully expanded. After stent placement, additional balloon dilation is usually performed to ensure full expansion of the stent.

D

Arterial rupture

E

If arterial rupture occurs during stent placement and the stent has been fully deployed, a balloon catheter is inserted and placed within the stent along the area where the rupture is thought to have occurred. The balloon is then inflated. A covered stent can be placed in the same location or emergency operative repair is undertaken.

Fig. 19.21  Self-expanding stent collapses in its mid-section. (A) A guidewire is placed across the lesion. (B) A stent is placed but remains partially constrained in its mid-section. This is most likely to occur in a heavily calcified lesion, especially when it is eccentric, that has not been adequately prepared prior to stent ­placement. (C) Balloon angioplasty is performed. (D) Because self-expanding stent hoop strength is low, a recalcitrant lesion may impinge on the stent, which results in incomplete expansion. A central stent narrowing can also occur if the stent is placed across a segment with too sharp a turn. (E) If angioplasty is unsuccessful, a balloon-expandable stent is placed to resolve the stenosis.

ACUTE COMPLICATIONS OF STENT PLACEMENT Complications that occur during stent placement or immediately thereafter include arterial dissection and/or occlusion, arterial rupture, migration or embolization of the stent, or embolization of atherosclerotic material.

Migration or embolization of the stent Migration of the stent may occur during deployment, usually because the size of the stent that was required was underestimated. Another potential cause is if the delivery platform is not stable and begins to move as the stent is deployed. If the stent has migrated enough that the area of interest has not been adequately stented, another stent should be placed in this location.

Embolization of atherosclerotic material Distal embolization may occur as a result of instrumentation of a friable atherosclerotic lesion. It is unusual for further embolization to occur after the entire lesion has been covered with stents. This is more likely to occur when treating occlusions.

Chronic complications of stent placement  253

CHRONIC COMPLICATIONS OF STENT PLACEMENT

stenosis occurs in juxtaposition to a stent, an overlapping stent is placed.

Chronic complications from stent placement that may develop over time include intimal hyperplasia, recurrent stenosis, infection, and damage to the stent from external forces.

Infection

Intimal hyperplasia and recurrent stenosis Intimal hyperplasia that causes recurrent stenosis can be treated with repeat balloon dilation, additional stents, atherectomy, or drug-coated balloon angioplasty. Surgery is usually reserved for situations of multiple endovascular failures. If recurrent

Infection of a stent is rare and is managed by excising the stent and the arterial segment.

Stent damage Stents can be damaged by external forces. Chronic repetitive shoulder motion with compression of a stented subclavian artery against the first rib leads to stent fracture. Stents can also be crushed, especially balloon-expandable stents, by arterial clamps, blood pressure cuffs, motion at joints, and external blunt trauma.

20 Other devices and how to use them MICROCATHETERS Microcatheters are small caliber, lengthy, flexible catheters that are compatible with small caliber guidewires. They may be used for strategic angiography, to exchange guidewires, and to provide support for a guidewire system in challenging situations. Microcatheters may be used to ­support crossing of chronic total occlusions (CTOs). Microcatheters may also be used to provide therapy, such as when small caliber coils are delivered or therapeutic medication is administered. Thrombolytic agents may be delivered through microcatheters, for example. Microcatheters are generally 2.3–3.8-Fr in caliber, in comparison to the standard 5-Fr catheter used with a 0.035-inch system (Figure 20.1). The tip of the catheter may be floppy or stiff and may be either straight or have angles at the tip. These catheters may be designed to accept a 0.10-inch, a 0.014-inch, or a 0.018-inch diameter guidewire. They come in lengths of 60 to 150 cm. The longer and smaller caliber the catheter becomes, the more the guidewire–microcatheter friction increases during wire passage through the catheter and also during catheter passage over the wire. Some microcatheters have radiopaque tips, which make them more readily visible, and some microcatheters have stiff tips. Microcatheters with stiff tips may be used for crossing occlusions. The catheter and the guidewire can be used in a hopscotch manner to get across an occlusion, each providing support to the other. Microcatheters may be used to provide support to a guidewire system where support is inadequate due to the  lack of strength of the guidewire shaft itself. The relationships of the guidewire to the surrounding tissues may be changed significantly by adding a microcatheter.

Microcatheters have significantly changed the practice of caring for vascular patients in several areas, including neurovascular applications and delivery of thrombolytic medication for stroke, and also in terms of tibial artery interventions and crossing tibial occlusions with a microcatheter with a stiff tip. Microcatheters have also provided a whole new dimension in terms of opportunities

5-Fr

A

3-Fr quick cross catheter B

2.3-Fr prowler C

2.5-Fr renegade D

Fig. 20.1  Microcatheters are used regularly as an adjunct in small vessel intervention. (A) A standard 5-Fr angiographic catheter. (B) A Quick-Cross™ (Support) catheter has a stiff tip and markers and is used to push across occlusions. (C) A Prowler® Select® microcatheter is a soft, floppy neurovascular catheter with an angled tip. (D) A Renegade™ (Hi-Flo™) microcatheter is a low-profile neurovascular catheter with a straight tip and a marker. 255

256  Other devices and how to use them

for wire exchange, visualization, passage of guidewire–catheter apparatus into tortuous and extremely remote locations, and also in terms of options for getting out of trouble. Several of the major companies make an array of microcatheters and these are mostly geared toward neurovascular applications, but their applications may be possible throughout all of the vascular systems.

RE-ENTRY CATHETERS Subintimal recanalization has been a true advance in the endovascular management of occlusions. This requires several steps including passage of the guidewire into the subintimal space, advancement along the subintimal plane, and re-entry into the true lumen of the artery that feeds the distal runoff bed. Among these steps, re-entry into the true lumen is the rate-limiting factor. Re-entry catheters are used specifically to assist in re-entry into the true lumen after a subintimal recanalization has been performed. When performing a subintimal recanalization, sometimes the looped hydrophilic wire supported by a catheter will pass spontaneously from the subintimal space to the true lumen. There is a tissue barrier between the false lumen and the true lumen, and the loop of hydrophilic wire sometimes interrupts it. Often, however, the looped hydrophilic wire stays in the subintimal space. This is especially true if the re-entry site is also diseased, calcified, or has a measureable thickness of plaque present. A re-entry catheter is designed to help the operator re-enter the true lumen at the desired location by means of a hypotube style needle thrust through the tissues, which permits passage of a guidewire through it. Very often there are large collaterals near the re-entry site, because this is also usually the site of reconstitution of the vessel. Large collaterals that occur at the desired location of recanalization are useful to preserve. In addition, very often the reentry site has some disease and some thickness of the tissue between the subintimal space and the true lumen that prevents a natural re-entry of the wire and catheter. There are two useful re-entry catheters available: (1) the Outback® catheter where the crossing needle is fluoroscopicallyguided; and (2) the Pioneer Plus catheter, which relies on guidance of the needle by IVUS. Both catheters use a needle that is well secured to the

tip of the catheter, is carefully oriented toward the true lumen using imaging, and is manually advanced using the sharp tip of the needle to pierce the obstructing tissue. The needle is hollow and allows passage of a wire through the needle and into the true lumen. This becomes the access for the intervention and the eventual repair of the occluded vessel. The Outback® Catheter has an “L”-shaped marker at the tip, which is viewed in multiple oblique directions under fluoroscopy. This helps the operator know which way the needle is pointed. The base

A

B

C

D

Fig. 20.2  Re-entry catheters. (A) A long SFA occlusion is crossed in the subintimal space. Because the wire loop was not successful at re-entry into the true lumen, a re-entry catheter is selected. (B) The re-entry catheter, either an Outback® catheter or a Pioneer Plus catheter, is placed in the subintimal space. (C) After the catheter is carefully oriented so that the re-entry needle is directed toward the true lumen, the needle is passed. The Outback® catheter is fluoroscopically-guided and the Pioneer Plus catheter is guided by IVUS. (D) After advancement of the needle into the true lumen, a 0.014-inch wire is advanced. The behavior of the wire as observed under fluoroscopy usually indicates whether the wire is in the correct lumen. This is confirmed angiographically. The needle is retracted and the catheter withdrawn over the wire.

Chronic total occlusion catheters and crossing catheters  257

of the “L” points toward the direction of the needle throw. This is typically done under a road mapping view so that the contrast within the reconstituted true lumen can be visualized. The catheter hub also allows the operator to turn or rotate the direction of the device in increments. This turning ability is essential to get the needle point in the correct direction toward the true lumen. Very often, the re-entry catheter has been passed upand-over the aortic bifurcation and through a long superficial femoral artery (SFA) occlusion, which adds friction. These anatomic factors contribute to a reduction in the maneuverability of the re-entry catheter. The subintimal space at the location of the catheter head should not be dilated, because a small subintimal space in this location helps secure the catheter tip so that the needle has support. Sometimes, numerous throws of the needle are required to reach the true lumen and permit the wire to be passed. The operator has the ability to adjust the throws of the needle so that they are only as deep as appears to be necessary based on the thickness of the tissue and the distance required. This is done primarily by the feel of the device and the experience of the operator. There are several similarities with the mechanism of the Pioneer Plus catheter. It is about the same size and relies on the orientation and manual advancement of a hypotube needle under visualization. Advantages of the Pioneer Plus catheter include: the distance of the throw of the needle is adjusted through a mechanism on the handle of the catheter; the turning of the catheter with the needle toward the true lumen is performed with guidance by IVUS. This makes the two-dimensional fluoroscopic image much less important for orientation and also helps decrease the number of throws of the needle that are typically required. Although the Pioneer Plus catheter is more expensive and requires availability of IVUS, the ability to place the needle accurately at the selected re-entry site and with fewer attempts is an advantage. For both devices, once the internal 0.014-inch diameter guidewire has been advanced into the true lumen, its location in the lumen is confirmed by the fact that it passes easily into the existing arterial anatomy. Usually, it is best to advance the wire as far into the true lumen as it will easily go. At that point the needle is withdrawn so that it is no longer protruding from the catheter head. The catheter is

then carefully removed, with attention paid to the integrity of the wire to avoid kinking or bending or partial withdrawal of the wire. Once this is done, it is usually best to advance a balloon that is compatible with a 0.014-inch diameter guidewire to create more space along the occlusion and also at the junction where the passage has been made from false lumen to true lumen. After this, the reconstruction can be done over the 0.014-inch diameter guidewire or the wire can be exchanged for a larger caliber wire before proceeding to definitive therapy.

CHRONIC TOTAL OCCLUSION CATHETERS AND CROSSING CATHETERS CTO catheters are catheters that are specially designed to support a guidewire in the traversal of a CTO. Typically, the wire is a CTO wire or a wire specifically designed for crossing occlusions. This is either a 0.014-inch or a 0.018-inch diameter guidewire. CTO wires typically have fairly stiff wire tip. Some have a hydrophilic coating. A  typical CTO wire tip will support a weight of 10–15 grams without bending to the point of a 180-degree turn. The CTO catheter is meant to be supportive. Therefore, the catheter itself may be somewhat stiff. It may have an angled tip or a straight tip, and a tapered tip that allows the catheter to be advanced to follow the wire with the least amount of friction. Examples of CTO catheters include the CXI® Support catheter and the Quick-Cross™ catheter. Both of these have radiopaque markers at the tip and along the shaft so that they can be identified under fluoroscopy and advanced as necessary. In general, when recanalizing a CTO, it is best to lead with the wire and then advance the catheter at intervals in order to support the wire. Crossing catheters have been developed to add mechanization to the crossing of a CTO. These are typically rotating units that help bore through an occlusion in the hope of keeping the guidewire in the true lumen while crossing the lesion. The Crosser® CTO Recanalization catheter provides a hydraulic force to assist the operator in crossing heavily calcified occlusions (Figure 20.3). Several other crossing catheters are available with the ­concept of manual rotation of the catheter, which permits the tip to function like a drill.

258  Other devices and how to use them

A

B

Fig. 20.3  Crossing catheters. (A) Crossing catheters add mechanization to the process of traversal of an occlusion. The crossing catheter is advanced to the leading edge or top cap (hard portion at the proximal end) of the occlusion. (B) This may be a rotating or hydraulic force. In this example, gentle forward pressure and a forward hydraulic force combine to advance the catheter through the occlusion while staying in the true lumen.

A

B

C

ATHERECTOMY Atherectomy is performed by a device that removes a portion of the atheroma from the luminal surface using a cutting sanding or grinding mechanism. There are different types of atherectomy devices, such as directional shaving devices and rotational devices (Figure 20.4). In each, a catheter is passed to the site of the target lesion and the plaque is modified according to the selected method. The advantage of these devices is the potential to remove some of the plaque and gain more space in the lumen, rather than just pushing the plaque aside as all the other methods do. In the noncoronary arteries, atherectomy is used primarily in the common femoral artery, the SFA, the popliteal artery, and the tibial arteries. When the common femoral artery is treated with atherectomy, directional atherectomy is the best tool. In other arterial segments of the lower extremity,

Fig. 20.4  Directional atherectomy. (A) The catheter handle contains the motor controls. The tip is tapered. The nose cone contains the cutting device and space to collect plaque specimen. (B) Close-up of the nose cone showing the cutting chamber in the open position. (C) When engaged for cutting plaque, the tip of the catheter becomes angulated. This allows eccentric positioning of the cutting chamber against the wall of the artery.

either atherectomy mechanism may be used. Laser may also be used to perform atherectomy and is the subject of the next section. Depending on the arterial segment treated, atherectomy may be used as a stand-alone treatment, but it is frequently combined with balloon angioplasty. One advantage of atherectomy is that there is a lower incidence of dissection than with a balloon-based revascularization mechanism and there is less need for stent placement afterward. There is a growing effort to understand the potential results of atherectomy followed by drug-coated balloon angioplasty in the superficial femoral and popliteal arteries. In general, atherectomy is another method of revascularization with conceptual advantages, but it has been challenging to prove its real advantage compared with other methods of lower extremity revascularization. The conceptual appeal has to do with the potential to restore the artery back to its native condition, restore significant lumen,

Atherectomy 259

modify the compliance of the vessel, and avoid at least some stents. The challenges with these devices include: the risk of distal embolization during the procedure; increased time and radiation associated with multiple device passes; and the incidence of recurrent stenosis on later follow-up. Atherectomy may also be employed in different ways, given the disease morphology and the vessel segment being treated. Atherectomy may be used to debulk eccentric calcium, debulk undilatable calcium, bore a hole large enough to pass a stent delivery catheter, as a vessel prep tool, or as stand-alone therapy. The operator must decide how the atherectomy device will be incorporated into an individual treatment plan.

Directional atherectomy A common directional atherectomy tool available is the SilverHawk (Peripheral Plaque Excision System) atherectomy device. This comes in different sizes depending on the lumen of the artery that is going to be treated. The larger devices, used for treatment of arteries proximal to the tibial vessels, are passed over a 0.014-inch diameter guidewire. The size of sheath required is either 6-Fr or 7-Fr, again depending on the size of the lumen. The atherectomy device is passed through the sheath to a point where the cutting chamber is visible fluoroscopically just proximal to the location of the lesion to be treated. When the catheter is properly positioned, the motor handle is engaged and the motor is turned on, which can be heard turning the cutting device, and the catheter is slowly advanced over the guidewire with the cutting chamber up against the plaque. When the motor is engaged, the catheter itself is designed to assume an angulated configuration at its tip, which helps direct the cutting chamber up against the wall of the artery at the site intended for plaque removal. The pass of the atherectomy catheter is performed under fluoroscopy. The guidewire is carefully held in place while the atherectomy cutting chamber is advanced. The atherectomy catheter is advanced at a fairly slow rate of approximately 1 cm every 5–10 seconds along the same plane so that it cuts a trough through one quadrant of the lesion. The atherectomy cutting chamber eventually passes the lesion and the motor is disengaged. This straightens the catheter tip. With disengagement of the motor, the cutting chamber is closed and

tamps down the atherectomy specimens that have accumulated in the chamber of the nose cone of the catheter. The wire is held steady as the atherectomy catheter is withdrawn until it is proximal to the lesion. The atherectomy catheter has on its shaft a steering device that helps assist in rotation of the catheter head to another quadrant within the lesion. By holding the shaft or handle of the catheter steady, the catheter may be rotated or pivoted and approximately six to nine clicks of the rotation will allow the cutting device to turn approximately 90 degrees. If it is not possible to see if the catheter is rotating with the clicks, the catheter may have to be withdrawn and readvanced slightly to remove any gathered tension. Sometimes, the potential energy of twisting is built up within the catheter and not expressed by movement at the level of the catheter tip and cutting chamber where the action is. After the catheter has been rotated approximately 90 degrees, the motor is re-engaged, opening the cutting chamber, and this allows the chamber to be advanced again across the lesion and another quadrant of cutting is performed. After each cut, the catheter is rotated approximately 90 degrees. When the cutting chamber becomes full or nearly full, the tamping device will only reach across the opening to the cutting chamber and will not reach all the way into the nose of the cutting chamber. This can be visualized fluoroscopically. When this is the case, the entire catheter is withdrawn over the wire. The cutting chamber is opened and the chamber flushed so that the atherectomy specimens can be removed. Once all the specimens have been removed, the atherectomy catheter is then passed again along the guidewire to the location of the lesion and additional atherectomy may be performed. Clinically significant embolization is uncommon, although it is common to produce emboli with atherectomy devices. It is quite common to have the impression that the lesion removed in terms of the actual specimens is much less than the amount of the lumen that has been created. There are some possible explanations for this. One is that the atherectomy specimens as they are removed are compressed into the cutting chamber, thus making them look smaller than they might otherwise have been while in situ. There may also be some rigid catheter dilation effect from the atherectomy device itself. Another concern is that the atherectomy cutting device works at a fairly constant rate

260  Other devices and how to use them

of speed, while the plaque being cut is heterogeneous. Some plaque is more solid and calcific and some is softer and more malleable. Therefore, as the atherectomy device is being pushed across the lesion, no matter how steady and gradually this is performed, there is the sense of skipping or hopping of the catheter head as the cutting chamber moves across the more calcified or difficult areas to cut. Atherectomy in the lower extremity is particularly useful at locations where stents are undesirable, such as where the artery will bend with flexing of the knee or the hip. In addition, the origin of the SFA, the origin of the tibial arteries, and possibly the common femoral artery are other locations undesirable for stenting that may possibly be well treated with atherectomy.

A

Rotational or orbital atherectomy

Fig. 20.5  Rotational or orbital atherectomy. There are a variety of devices available. Each one is passed over a guidewire and has some variation in the concept of a cutting head or sanding burr. (A) A posterior tibial artery occlusion is identified by arteriography. (B) An antegrade sheath is placed and a guidewire advanced across the lesion. (C) A rotational atherectomy device is advanced to the proximal end of the occlusion. The burr is motorized and the lesion engaged. The atherectomy burr is advanced slowly through the lesion to create a lumen.

Rotational atherectomy involves a rotating head that is power driven and rotates at thousands of revolutions per minute. The speed with which the mechanical tip rotates will determine the heat that it generates and the efficiency with which it turns the atherosclerotic plaque into particulate. The faster the rotation, the smaller the particulate. Rotational atherectomy requires several passes of the rotating head along the length of the lesion being treated. The highest rotation speed utilizes a sanding burr and results in orbital atherectomy. As the rotation speed increases, the orbit made by the tip typically increases in size. Therefore, passes may be done with increasing rates of speed to obtain a larger luminal gain. This may be helpful in heavily calcified lesions of the SFA to modify the plaque enough so that it can be manipulated more easily with subsequent balloon angioplasty. In some of the heavily calcified tibial vessels, there will be lesions that are immune to angioplasty but could be pumped opened with rotational atherectomy. There are several companies that make rotational or orbital atherectomy devices with a variety of features. They are all passed over a guidewire for extra control. As the tip is advanced through the lesion, it is advanced slowly so that it is permitted to do a complete job of plaque modification. There are auditory cues that reflect the interaction between the rotating tip and the lesion. Some devices may be advanced or retracted while the burr is spinning. Some devices feature a continuous flush to cool the device tip while others feature continuous aspiration to remove particulate matter.

B

C

LASER Lasers are being used both in the coronary and noncoronary arteries and in the venous system. The peripheral laser may be used as a crossing device, to perform atherectomy, or as a thrombectomy device. Reconstruction of the artery is usually accomplished with some other modality, such as a drug-coated balloon or stent. When laser is used as a crossing device, it is usually in the management of a SFA or tibial artery occlusion. These are typically fairly straight arteries that follow a mostly predictable course. If there is a highly calcified cap on a lesion that prevents entry to the occlusion to be recanalized, the 1-mm laser tip can be parked with the guidewire at the cap (hard portion) at the end of the occlusion and the laser energy used to create an entry point for the wire (step-by-step approach). After the laser

Drug-coated balloons and drug-eluting stents  261

is used against the cap, the wire is advanced a few millimeters, then the laser is advanced and the process repeated. Laser also has the capability of vaporizing thrombus and can be used to chase peripheral embolus that occurs during complex lower extremity revascularization. A wire is passed beyond the embolized material. The laser must be advanced over the wire directly into the thromboembolus before being activated. The laser may be used to recanalize by treating chronic compacted thrombus, acute thrombus, or plaque. Laser may also be used to perform debulking of plaque by means of laser atherectomy. Quite often, laser is used as an adjunct along with some other method. After debulking, it is common to use a balloon to gain additional lumen. Laser catheters come in different sizes and each size has a range of diameters for arteries for which it can be used (Figure 20.6). The laser is passed over a guidewire. The tip of the laser catheter is advanced to within less than a centimeter of the lesion for crossing and the laser is activated. The laser is advanced very slowly to perform even treatment of the plaque.

A

B

C

D Fig. 20.6  Laser for peripheral artery use (CVX300 ® Excimer Laser System). (A) The tip of the laser catheter. (B) The laser booster is a cradle that allows a broader sweep of the arterial lumen for the tip of the catheter. (C) Laser atherectomy is being performed over a guidewire. (D) Laser atherectomy is being performed to a wider diameter using a laser booster.

In addition, there is a sled or booster that can be used to carry the laser catheter. This permits a slight angulation of the laser tip and this device may be rotated within the artery to bore a larger space and create a larger passageway. Laser debulking has been successful in recanalizing occluded SFA stents. Removal of the tissue and chronic thrombus helps create a lumen that cannot be achieved with the angioplasty mechanism alone. The key is to advance the catheter very slowly so that the tissue in-growth can be treated. Laser has been used with success in SFAs to reopen occlusions and is frequently used in combination with angioplasty and/or stenting. The laser is another device that is in the midst of a resurgence after previous efforts have not been found to be substantially valuable. The utility of this tool will be determined sometime in the coming years as additional data is accumulated.

DRUG-COATED BALLOONS AND DRUG-ELUTING STENTS The concept of drug delivery to help reduce restenosis has arrived in the peripheral vasculature. A  key feature of the drug delivery paradigm is that each segment that is treated should also have a drug applied to enhance long-term results. Drugs may be delivered by drug-coated balloons or drug-eluting stents (DESs). The drug must be attached to the balloon or the stent by some ­mechanism. Drug-coated balloons have an excipient and DESs use a polymer. The crystalline f­ormulation of paclitaxel is readily transferable to the wall of the artery on balloon inflation. Each drug-coated balloon has an excipient, which binds the paclitaxel to the balloon surface tightly enough to be delivered but loosely enough so that it can be transferred to the artery wall on balloon inflation. Paclitaxel is a common antineoplastic medication and is the primary medication currently used for drug-coated balloons. They are applied to lower extremity revascularization and dialysis access treatment. Paclitaxel is cytotoxic and there is evidence that it can lead to positive remodeling with decreased late lumen loss. As already mentioned, the more crystalline the preparation, the more readily transferable it is to the artery wall. The more amorphous the preparation, the more challenging it is to transfer to the wall. One negative aspect of the crystalline preparation

262  Other devices and how to use them

A

B Fig 20.7  Drug-coated balloon. (A) A standard angioplasty balloon has a smooth, clear surface. When expanded, it is transparent. (B) Drugcoated balloons generally consist of the same type of balloon but covered with a medication preparation. The medication causes the surface of the balloon to appear opaque. In its expanded state, there is typically a coarse appearance to the surface. The balloon itself should not be manually manipulated prior to insertion because this can disrupt the medication.

is the potential for particulate paclitaxel crystals to be washed into the distal runoff. There are some technical aspects to drugcoated balloon angioplasty that must be followed in order to obtain better results. Do not wipe the balloon; this will prevent medication washing off the balloon surface. In placing the balloon into the sheath, plan to have the balloon inflated at the site of treatment within 30 seconds, so that it is not sitting for a prolonged period in the blood stream. The balloon should be inflated for a minimum of 2 minutes, and 3 minutes may be better. The balloon should be inflated to at least 7 or 8 atm of pressure and should be sized to the artery at a 1.1 to 1.0 ratio. Predilation should be performed with a balloon that is the same size as the reference vessel diameter or 1 mm smaller. If a single balloon is not adequate to cover the whole length of the lesion, make sure that there is a slight overlap between the two balloons to avoid a geographic miss. The medicated portion of the balloon should extend beyond the lesion for a few millimeters to a centimeter. After drug-coated balloon angioplasty, when dissection results, spot treatment is recommended to minimize the amount of metal being implanted. DESs have had a significant impact in the care of coronary artery disease but a less significant impact in the treatment of noncoronary artery disease. There is one FDA-approved stent in the US  for the treatment of SFA occlusive disease

(Zilver® PTX® Drug-Eluting Peripheral Stent). This device is a self-expanding nitonol stent, uses paclitaxel, and is supported by 5-year data from a prospective randomized trial. There are no approved DESs for the tibial arteries, although there have been trials using a coronary DES off-label in the tibial arteries. Several trials are currently evaluating DESs in the superficial femoral and tibial arteries. The concept of the DES is to coat the stent with a drug that is gradually delivered to the artery wall in a sustained manner. The drug is intended to cause a diminishment, if not inhibition, of cell division at this location so that intimal hyperplasia may be prevented. One issue central to the DES mode of action is the method by which the drug adheres to the stent. In the coronary arteries, this typically involves adherence to a polymer that is coated onto the surface of the stent. This is also being developed for the lower extremity a­ rteries. Studies in the coronary arteries using DESs have shown just such an effect. The drug delivery, however, is for a finite period of time. The coronary arteries are, of course, much smaller than the superficial femoral and popliteal arteries and the same mechanisms of action may not take place in these locations.

CUTTING, SCORING, AND CRYOPLASTY BALLOONS The mechanism of balloon angioplasty is discussed in Chapter 17. Modified angioplasty balloons are designed to improve the angioplasty mechanism for a variety of reasons including exerting more force, modifying the plaque, or causing less injury. The concept of a cutting balloon is to place a cutting device on the outside of the balloon so that when the balloon is inflated the blade will cut the lesion (Figure 20.8). This will provide the potential for a more predictable cleavage plane when balloon angioplasty is performed. Cutting balloon angioplasty was developed to treat coronary in-stent restenosis but it has been only moderately successful in this application. Cutting angioplasty balloons are approved for both coronary and noncoronary usage. The smaller diameter balloons are in 0.5 mm incremental steps up to 4.0 mm in diameter. These are monorail platform, 0.014-inch compatible. The larger balloons are in 1 mm incremental steps from 5 mm to 8 mm. Because the atherotomes make the balloon relatively rigid, these

Cutting, scoring, and cryoplasty balloons  263

A

B

D C

Fig. 20.8  Cutting and scoring balloons. (A) The cutting balloon has blades or atherotomes on its side. (B) When the balloon is inflated, the cutting blades dig into the plaque. (C) The blades create an impression on the luminal surface of the plaque. (D) Scoring balloons have a wire on the outside surface that can be oriented longitudinally or circumferentially (shown). When the balloon is inflated, the wire engages the artery wall and the lesion.

balloons are fairly short. The blades have T-shaped notches in them to assist with flexibility, although they still remain somewhat rigid. When the balloon is inflated, it is usually not possible to see a waist since the balloon sides are fairly rigid and expand all at once. The cutting balloon usually expands at fairly low pressures since the blades incise the tissue and allow expansion of the balloon. It is rare to proceed to a nominal pressure of approximately 8 atm without expanding the balloon. These balloons are semi-compliant. Caution should be exercised to avoid overinflation for fear that a rupture of the balloon may cause loss of an atherotome. The smaller caliber balloons are 1.8 cm in length and the atherotome is 1.5 cm in length. Care should be exercised when inserting the balloon into the sheath. Avoid cutting a finger by supporting the relatively stiff balloon catheter at the back end of the balloon with a pincer grasp as it is pushed into the sheath. After that, it advances in a manner much the same as any other monorail platform balloon. There are a variety of concepts around modified balloons that are different from cutting balloons. Scoring balloons typically have a wire mounted on the balloon surface but external to the balloon. When the balloon inflates the wire is pushed into the lesion and into the wall of the artery. This design

can also be called a focal force balloon because the force of the angioplasty balloon is focused on the wire. This dramatically increases the force with which the wire penetrates the wall of the artery. The wire may be in a longitudinal orientation or it may be in a circular or slanted orientation. Scoring balloons have been used for a variety of purposes, as detailed below. Scoring and cutting balloons have applications in in-stent restenosis, recurrent stenosis due to intimal hyperplastic tissue, vein graft stenosis, stenosis within dialysis grafts, central vein stenoses, and pulmonary artery stenoses. Heavily calcified lesions may also be treated with modified balloons. When infrainguinal vein bypass grafts or central vein stenoses are treated, consider undersizing the balloon; it should be large enough to incise the lesion but not large enough to cut the juxtaposed normal vein tissue. Then follow up with a balloon sized to the desired final diameter. Scoring and cutting balloon angioplasty has also been used for focal infrainguinal artery lesions. Scoring balloon angioplasty may be used for heavily calcified common femoral artery lesions in patients who are not candidates for open surgery to perform femoral endarterectomy. Cutting or scoring may be useful with focal tibial artery lesions where standard angioplasty is somewhat limited because of the

264  Other devices and how to use them

undesirability of placing stents in the tibial arteries. When the balloon is inserted into the correct location, it is inflated slowly over the course of approximately 30 to 60 seconds. This is done so that the atherotomes or outer wires may correct themselves and separate along the inner circumference of the blood vessel wall. If further angioplasty is required, it is usually appropriate to follow the scoring or cutting balloon with a standard angioplasty balloon and to open the caliber of the blood vessel further, since the cleavage planes have been made within the plaque or within the scar tissue that represents a lesion. Both scoring and cutting balloons are a little larger in their profile than plain balloons of equal caliber because the blades or wires are on the outside of the balloon. After balloon inflation, the balloon catheter is aspirated aggressively in an attempt to shrink it down to its smallest possible size prior to removal.

Cryoplasty involves cooling of the inflated angioplasty balloon in an attempt to induce apoptosis. The idea behind cryoplasty is that cell division can be interrupted and potentially even the process of recurrent stenosis could be diminished or prevented using cooling of the artery and the surrounding tissues. There is a substantial amount of science behind this but whether or not it actually decreases long-term rates of recurrent stenosis has not been conclusively shown. Cryoplasty is another potential option that may be used in locations where stenting is undesirable. The cryoplasty apparatus includes a balloon catheter that has multiple layers (Figure 20.9). When the balloon is inflated, the multiple layers are designed to prevent leakage of nitrous oxide. Because the balloon has multiple layers, the caliber of the sheath required is either 6-Fr or 7-Fr depending on the size of the balloon diameter that

A

B

C

Fig. 20.9  Apparatus for performing cryoplasty. (A) A multilayered cryoplasty balloon in its deflated and inflated states. (B) The control panel connects to the cryoplasty catheter. (C) A nitrous oxide canister is used to inflate the balloon.

Peripheral stent–grafts  265

is desired. The balloon catheter is connected to a pump and when the balloon is located within the lesion, the catheter is aspirated to clear the lumen of any air or nitrogen that may be there. The pump is then set into action at the press of a button. Nitrous oxide is pumped into the balloon catheter and then cooled to −10oC. The balloon is inflated gradually over the course of several seconds and is inflated to a very reproducible level of 8 atm. This helps to decrease the likelihood that the balloon could be punctured or ruptured and also helps to achieve a very even type of dilation. Gradual inflation and the very steady pressure increase over the course of a couple of minutes helps to minimize dissection. This minimization of dissection is something that is apparent when using the cryoplasty apparatus. The other piece of the system is a nitrous oxide canister, which may be placed within the pump at the appropriate time. After angioplasty is completed, the catheter must be vented, and after it is vented a negative aspiration is drawn. This helps to empty the balloon and as it empties the blood flows around it and rewarms the balloon. Once the balloon is rewarmed, it may be repositioned for an additional inflation. Cryoplasty has been used quite extensively in the lower extremities in the superficial femoral, popliteal, and tibial arteries, especially in locations where stenting is undesirable.

PERIPHERAL STENT–GRAFTS Stent–grafts have broad applications in relining the aorta and iliac arteries when treating aneurysmal

A Fig. 20.10  Peripheral stent–graft. (A) This self-expanding stent–graft has a nitinol skeleton and a PTFE cover and is delivered on a catheter (Viabahn™). The handle of the catheter contains a ripcord type mechanism, which is pulled to release the graft. (B) After deployment, the graft is self-expanding and somewhat flexible. (C) Balloon-expandable covered stents are also available. The balloon-expandable stent segments are recognizable and are held together longitudinally with PTFE and covered with PTFE.

B

C

disease. There are several other conditions that may require stent–graft placement. Stent–grafts or covered stents could be self-expanding or balloonexpandable. Stent–grafts available for peripheral use include the Viabahn™ stent–graft, the Fluency™ stent–graft, the Wallgraft™, the iCast™, the Viabahn® balloon-expandable stent, and the Lifestream® balloon-expandable covered stent. All of these devices have a bulkiness beyond standard stents and require larger sheaths for placement. The uses for stent– grafts are being evaluated and their indications for use in the treatment of occlusive disease of the lower extremity are an active area of investigation. In general, the lower extremity arteries may be treated with self-expanding covered stents to accommodate the flexibility of these arteries. Self-expanding covered stents, usually Viabahn™, are used to treat popliteal artery aneurysms. Either balloon-expandable or self-expanding stents may be used in the aortoiliac segment to treat iliac occlusive disease or to perform a completely covered aortoiliac reconstruction. Parallel grafts used as branches in conjunction with endovascular aortic aneurysm repair may be performed with either balloon-expandable or selfexpanding grafts. When self-expanding covered stents are used as parallel grafts, they are typically reinforced with bare metal stents to avoid being compressed. The Viabahn™ stent–graft has an indication for use in the SFA (Figure 20.10). It is a nitinol mesh stent–graft with a polytetrafluoroethylene (PTFE) covering. It is relatively flexible and has low chronic outward force. It is deployed using a ripcord style deployment system. Viabahn™ stent–grafts are

266  Other devices and how to use them

available in lengths from 5 to 20 cm. The diameters in which they are available range from 4 to 10 mm. Viabahn™ stent–grafts require sheath sizes anywhere from 6-Fr to 9-Fr and the sheath sizing charts and specific catheter availability should be consulted prior to any case. When treating a lesion with Viabahn™ stent– grafts, the aim is to achieve a seal within the artery and in a graft-to-graft fashion of approximately 3 cm. Viabahn™ stent–grafts may be oversized slightly, but if they are oversized too much there will be wrinkling and corrugation of the material within the area of the lumen of the blood vessel. The Viabahn™ stent–graft is prepackaged on a delivery catheter that is placed through the sheath and then, when it is in its proper location, the ripcord is pulled and the graft is deployed. Appropriate measuring of both the length and the width required should be performed prior to placement of the graft. Viabahn™ stent–grafts have been used to treat peripheral artery aneurysms throughout the body including carotid, renal, visceral, iliac, and popliteal vessels. They have also been used to treat occlusive disease in the SFA and the iliac artery and, occasionally, in other locations. After the stent–graft is placed, balloon angioplasty is performed, including connections and at the ends of the graft, to ensure that it is fully expanded. Patients who are treated with stent–grafts are typically maintained on antiplatelet agents or anticoagulation and occasionally both. Other types of stent–grafts in the peripheral arteries include the aforementioned grafts. The Fluency® graft is a nitinol stent covered with a PTFE. It is stiffer than the Viabahn™ stent–graft. Because it is more rigid, it is useful for relatively straighter conduit arteries. This is also a useful device for iatrogenic or traumatic injuries to the subclavian, superficial femoral, and other arteries. The Wallgraft™ is also somewhat rigid and has handling and placement properties similar to the Wallstent™, but its delivery is larger in caliber due to the PTFE covering. There is some length variability at the time of deployment since the final deployed length is dependent on the diameter to which it is deployed. The contourability is poor as it remains relatively rigid. The iCast™ and Viabahn™ VBX are balloon-expandable metal stents with a graft material covering. These are generally shorter and more rigid than the self-expanding covered stents and accuracy of placement is quite good since it is balloon expandable. They are useful for

vessel artery origin lesions such as the renal, subclavian, or common carotid arteries. Even if ­vascular trauma is not a significant part of the work load, it is a good idea to have some stent–grafts available in case an injury, traumatic or iatrogenic, presents in the course of usual vascular practice.

THROMBECTOMY AND THROMBOLYSIS The intent with both chemical and mechanical thrombolysis is the removal of thrombotic material from the vascular system. In the case of chemical thrombolysis, the thrombolytic agent is delivered directly into the thrombus. Chemical thrombolysis has been available for several decades and has been through various iterations with different agents and approaches. The development of mechanical thrombectomy devices has prompted efforts to optimize treatment by combining chemical and mechanical thrombolysis in each case for a faster and more complete thrombus removal. Chemical thrombolysis calls for pulse spray administration of thrombolytic agent directly into the thrombus, followed by an infusion of the same agent over a period of hours and up to 24 hours or, occasionally, a little longer. In the case of mechanical thrombolysis, there are various macerating, churning, or aspirating type devices that may be used to disrupt thrombus and remove it. The relative advantages of chemical thrombolysis are the avoidance of injury to surrounding tissues and access of the medication to the thrombus regardless of other nearby lesions. In general, this is a more gentle process than mechanical thrombolysis, but it often takes too long. Longer procedures are not feasible in the setting of acute ischemic pain or ischemic organ damage and they expose the patient to longer intensive care stays, higher doses of thrombolytic agents, and greater risk of bleeding. The advantages of mechanical thrombolysis are the ability to quickly debulk the clot burden and restore flow, and to speed the procedure along and avoid prolonged ischemia and prolonged chemical thrombolysis sessions. The disadvantages of mechanical thrombolysis are mostly logistical: investment in equipment and time is required; during the procedure larger sheaths are needed; each device has its learning curve; and the ­thrombus cannot always be reached. Very often,

Thrombectomy and thrombolysis  267

the mechanical thrombolysis debulks the thrombus but does not clear it completely. Therefore, thrombolysis procedures are often performed with a combination of both chemical and mechanical thrombolysis; these two techniques are used in concert to achieve a faster and safer result. If thrombotic or embolic problems occur during an endovascular procedure, the best initial step to address the problem is aspiration thrombectomy (i.e., place a catheter in proximity to the identified thrombus and aspirate). This is a useful adjunct and is sometimes required on unanticipated occasions. Aspiration may be performed using a specifically designed aspiration catheter or a small sheath. Several companies make aspiration catheters (e.g., Export® AP Aspiration catheter). These are typically 5-Fr or 6-Fr catheters with an end-hole for aspiration and a monorail delivery. It is useful to have one of these on hand in case an embolus occurs during a routine procedure. A commonly used chemical thrombolytic agent is tissue plasminogen activator (tPA). tPA is mixed in normal saline at a specific concentration and administered in a variety of ways. One common method is as follows. Place a sheath close to the thrombus. Enter the thrombus with a guidewire and pass a catheter over the wire and through the  thrombus. Lace the clot with thrombolytic agent using rapid injection of the agent directly into the thrombus. This is performed with a 1-mL syringe, injecting into multiple locations along the length of a thrombus while gradually withdrawing the catheter over the guidewire so that the thrombolytic agent can be evenly distributed. This is the pulse spray technique. After this is performed, a

Fig. 20.11  Chemical thrombolysis. (A) An occlusion of the distal popliteal and proximal tibial arteries is present. (B) An antegrade sheath is placed and a guidewire advanced across the thrombus. (C) Through the sheath, a multiple side hole soaker hose or thrombolytic therapy catheter is placed. (D) Thrombolytic agent is infusing through the side holes and end hole of the catheter to help dissolve the thrombus and also maintain patency of the runoff vessel. Heparin is also infused through the side arm of the sheath to help prevent new thrombus from forming in the area of the sheath or catheter.

A

soaker hose-type catheter with multiple side holes is advanced into the thrombus and the guidewire is removed in exchange for an end-hole wire, which can be used to infuse thrombolytic agent into the distal runoff (Figure  20.11). Put the guidewire through the lumen of the soaker hose catheter. This forces the thrombolytic agent out of the side holes of the catheter. Two drip infusions are set up: one through the soaker hose catheter itself and one through the end-hole guidewire so that the tip of the wire is also infusing tPA. The tip of the guidewire is infused so that the runoff blood vessel, whether it is in the kidney, in the lower extremity, or in other locations, may be protected from thrombus accumulation. Soaker hose catheters can also be obtained that have a valve on the end so that the lytic agent does not all runoff into the distal vasculature and miss the thrombosed segment of artery. Heparin is infused through the side arm of the entry sheath at a subtherapeutic level to prevent thrombus from accumulating in association with the sheath. During infusion with thrombolytic agent, the patient undergoes intermittent laboratory analysis including hematocrit, platelet level, thrombin level, prothrombin time, and partial thromboplastin time. If the thrombin level drops below 100 IU/mL, the lytic agent should be stopped. The  complications of chemical thrombolysis increase with the time required for the infusion and the overall dose. A typical dosing regimen for tPA for an occluded lower extremity bypass is to lace the clot with 2–6 mg of tPA then run the infusion at 1 mg/hour for 4 hours and then decrease it to 0.5 mg/hour after that. Most of the improvement that can be expected

B

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D

268  Other devices and how to use them

will be seen within the first 8  hours. Typically, if there is a change clinically or if several hours have gone by, then it is time to repeat the angiography and check the progress. Chemical thrombolysis may be combined with aspiration thrombectomy. A standard aspiration catheter may be placed over the guidewire and used to aspirate any thrombus that can be removed in this manner. There are several devices available for mechanical thrombolysis. One commonly used device with a broad variety of applications is the AngioJet ™ Peripheral Thrombectomy System device (Figure 20.12). When this device is used, a rapid spray of heparinized saline is infused and simultaneously aspirated. This creates a Bernoulli-type effect, which emulsifies the clot, converts it into very small particulate, and allows it to be removed with the effluent from the catheter. The device has several different types of catheters that are geared for blood

vessels of a variety of diameters. Care must be taken to choose the appropriately sized catheter and to advance it over the guidewire. As the catheter approaches the thrombus, the machine is engaged, the catheter advanced slowly, and the clot gradually removed. This device may be used alone or in conjunction with chemical thrombolysis to help remove clot. Very often, a thrombolysis case will be initiated with pulse spray using the AngioJet™. This is done by temporarily occluding the effluent from the catheter so that a small amount of infusion of lytic agent is placed at high speed and efficiency directly into the clot. After waiting a pre-set time, usually 15–30 minutes, the AngioJet™ is passed over the guidewire several times to remove thrombus. After several passes, interval arteriography is performed. If thrombus removal is incomplete, catheter-based chemical thrombolysis is established. One major limitation of the AngioJet™ Fig. 20.12  The Angiojet™ mechanical thrombectomy catheter. (A) The mechanical thrombectomy catheter is passed over the guidewire. (B) When engaged, the catheter tip simultaneously provides administration of fluid and aspiration of effluent.

A

B A

B

C

Fig. 20.13  Penumbra thrombus aspiration device. (A) An occlusion of the popliteal and proximal tibial vessels is identified. (B) An antegrade sheath is placed. The Penumbra Aspiration Device catheter with the soft tip is advanced to the area of thrombus and the suction mechanism is engaged. The catheter can be gently advanced to chase and aspirate the thrombus. (C) The catheter is connected to a suction pump that is specially designed to accompany the catheter and remove the thrombus.

Distal embolic filters  269

is hemolysis; continued usage causes ongoing damage to circulating red blood cells and this is manifested by the patient’s blood-colored urine, decreased hematocrit, and even hemodynamic instability. The patient is maintained on full anticoagulation during mechanical thrombectomy. The Penumbra Aspiration Device is a suction or aspiration device. A smooth and well-engineered catheter is advanced into the area of thrombus. Extreme and continuous suction is applied to remove the thrombus. There is also the potential to macerate the thrombus with an associated catheter to help assist with aspiration. The catheter can be moved to position it in the right location for thrombus removal and the aspiration catheter tip is gentle enough that it can be advanced into the thrombus with minimal risk of arterial injury. This is particularly useful when thrombus has formed in a lower extremity artery and the patient is profoundly ischemic, and the time to treat must be as rapid as possible. There are different sized catheters, including 3-Fr, 6-Fr, and 9-Fr, for different indications.

A

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DISTAL EMBOLIC FILTERS Distal protection devices, or embolic protection devices, were developed for use in the carotid vascular bed (Figure 20.14). Other applications include protection during renal stenting or complex lower extremity revascularization. Recanalizing or debulking an occluded SFA stent is another situation in which a filter may be of value. Likewise, during atherectomy of long or heavily calcified SFA lesions, embolization is a risk and filters probably play a role in making the procedure safer. Distal protection devices have some risk and cost of their own. In the carotid circulation, protection is considered mandatory during stenting, but distal filters may not provide complete protection for the brain. It is likely that the filters catch most major emboli and this makes them useful for the lower extremity. Distal protection devices were first approved for use in the coronary circulation when there is stenosis within a previously placed coronary vein graft. There are several approved distal protection devices for carotid stenting. Some  of

Fig. 20.14  Distal embolic protection devices. (A) The Emboshield NAV6™ is a free wire system comprised of a 0.014-inch guidewire with a 0.019-inch knob on it near the tip and the selfexpanding filter held open with nitinol struts. (B) The AngioGuard® is a fixed wire system with a short landing zone and an umbrella-like structure. (C) The FilterWire EZ™ is a fixed wire system with an eccentric nitinol hoop and a windsock.

270  Other devices and how to use them

them are approved for use along with a concurrently used stent such as the Emboshield NAV6™ and the Accunet®. Other devices, such as the Spider filter (SpiderFX™ Embolic Protection Device), are approved for use with any of the approved stents. Distal protection devices function by being placed beyond the lesion prior to treatment. There are two competing design concepts: one is a fixed wire system (filter is fixed to the guidewire and the wire and filter are placed together) and one is a free wire system (wire and filter are separate; first the wire is placed and then the filter). The Accunet® and the FilterWire™ are examples of fixed wire systems, where the filter is fixed in place along a guidewire. A short segment of soft directional wire, which is used to cross the lesion, extends from the tip of where the filter is fixed on the shaft of the guidewire. Once the tip of the wire is across the lesion, the filter delivery catheter is advanced until the filter, which is compacted tightly into the filter delivery catheter, is also across the lesion. After the filter has crossed the lesion, a covering membrane is withdrawn and this allows the selfexpanding filter to deploy and set its position. The alternative design, the free wire systems, includes the Emboshield NAV6™ and Spider filter. With the Emboshield NAV6™, a specially designed guidewire is passed across the lesion. This guidewire has a shapable tip and comes in several different wire body strengths. There is a 0.019-inch diameter knob on the body of the 0.014-inch guidewire close to the tip and this knob is used as a stop for the filter to prevent it from going off the end of the wire. In this case, the wire is placed first, separate from the filter. The guidewire behaves more like a traditional guidewire, without the bulky filter on the wire during passage. After the guidewire is across the lesion, the filter delivery catheter is advanced and the filter is deployed along the wire. The Spider filter is different in that it allows the use of any guidewire that is 0.014 inches in diameter. Subsequently, a microcatheter is passed over the initial guidewire of choice, the wire is removed, and then the filter is placed through the microcatheter. The filter is then deployed. During the procedure the filter is maintained in place. With the free wire filter systems, it is possible to have minor wire movement without significant filter movement. With the fixed wire system, any movement of the wire will also cause movement of the filter. The fixed wire systems permit crossing of the

lesion and placement of the filter in a single step, whereas the free wire systems require separate maneuvers for each of these steps. In each of these systems there is some component of nitinol scaffolding, which provides for the self-expanding properties of the filters. The filters have a specific pore size or a range of pore sizes. In general, most of the filters have pore sizes between 110 microns and 400 microns. There is a range of expanded filter diameters, generally from 3 to 8 mm, and a range of filter lengths. At the conclusion of the procedure the filter is recaptured. In  each case, the filter recapturing catheter is larger than the delivery catheter, with the rationale being that once the lesion is treated the lumen will accommodate a somewhat larger catheter in order to pass through and capture the filter. In addition, it is not desirable to squeeze the filter into as small a diameter as when it is an empty new filter, just in case the filter is full of debris. Filters may prevent a disastrous case of untreatable distal embolization. However, filters also have pitfalls. There is the potential that with the release of embolic material, filtration will not be complete or that the embolic material may spill out prior to retrieval of the filter. An additional concern is that if the pore sizes in the filter itself are too large, embolic material may pass through the filter, but if the pore sizes are too small, it will induce thrombus formation and may cause a slow flow situation. The support structure for the filter is in the direction of the lesion. When a stent delivery catheter is advanced over the guidewire, if the tip of the catheter encounters the filter support system, it may become entangled and irreversibly caught and necessitate some other type of drastic action to complete the procedure. Damage to the artery may occur during filter placement for recapturing. Placement of the filter delivery catheter itself could cause embolization. Recapturing the filter may be challenging in a tortuous anatomy. Lesions of significant complexity are being revascularized using endovascular techniques in many different vascular beds. The potential benefit of using filters in other locations is being explored. Indications for filters may include renal angioplasty and stenting, complex lower extremity revascularization, atherectomy cases, subintimal angioplasty cases, treatment of acute or chronic thrombus formation with mechanical thrombectomy devices, and during coil embolization cases to prevent distal

Distal embolic filters  271

embolization of coils. There is a risk:benefit ratio associated with the filter when used as an adjunct. Most of the existing filters have been designed for coronary or carotid ­circulations and have not been designed for renal, lower extremity, or other applications. The filter systems are somewhat restrictive with respect to the strength of the guidewire that is used to support the filter. The filter has a length that requires a specific landing zone, varying from 2 to 4 cm. This distance of nondiseased artery distal to the lesion may not be available in every anatomic bed. The diameter range for each filter varies, but it is u ­ sually 4–7 mm to fit with the distal internal carotid artery. Outside this ­diameter range, there are no appropriate filters. The filter itself may cause damage to the artery in the runoff bed and manipulation of the wire in this area may also cause damage. Most of the earlier discussion concerns distal protection devices. There are two other types of protection devices, which are not filters but are occlusive devices. These devices provide protection by using occlusion to either stop prograde cerebral flow or to reverse it. An example of a distal occlusion device is the PercuSurge  Guardwire™,

which  is approved for coronary vein grafts. The guidewire is a hypotube with a lumen in it. A balloon is mounted on the tip of the wire and passed across the lesion. Using a special device, the hypotube is opened and fluid administered to fill the balloon until occlusion of the distal artery is achieved. Treatment is undertaken and after this is done, an aspiration catheter is passed over the guidewire with flow at a standstill. The area is ­aspirated of any potentially embolic material. After multiple aspirations, the balloon is deflated and the guidewire with the balloon on it removed. There is also a proximal occlusion balloon system (the Mo.Ma™ Ultra Proximal Cerebral Protection Device), which may be combined with reversed flow to achieve distal protection. This is performed with a transfemoral sheath that is quite sizable, up to 9-Fr to 11-Fr. The sheath is advanced into the common carotid artery. The balloon is inflated to stop forward flow in the common carotid artery. Backbleeding flow from the external carotid artery is occluded with an occlusion balloon. Prograde cerebral flow is stopped and the carotid is aspirated vigorously after the stent is placed but before flow is restored.

III

Part    

Therapy in specific vascular beds

21 Brachiocephalic interventions 275 22 Visceral and renal artery interventions 297 23 The infrarenal aorta, aortic bifurcation, and iliac arteries: Advice about balloon angioplasty and stent placement 311 24 The infrainguinal arteries: Advice about balloon angioplasty and stent placement 329 25 Complex lower extremity revascularization 345 26 Salvage of previous reconstructions 373 27 Hybrid procedures 381 28 Technical aspects of treating aortic aneurysms 391 29 Coiling of peripheral aneurysms 419 30 Puncture site management 427

21 Brachiocephalic interventions INTRODUCTION Brachiocephalic interventions are being performed with increasing frequency. Endovascular approaches have replaced open surgery for most cases of common carotid and subclavian diseases. The role of carotid bifurcation stents is not yet determined, but they will have some role in treatment. In this chapter, these areas are described.

ARCH ASSESSMENT As more data has been gathered about carotid bifurcation stent placement using a transfemoral approach, it has become clear that a significant portion of the stroke risk associated with the procedure is related to the aortic arch. Because of this, patients with arch disease or significant angulation may be at increased risk for carotid artery stent (CAS) placement. Assessment of the arch, therefore, is an important part of patient assessment and procedural planning. Preoperative assessment is best performed using CTA. This permits simultaneous assessment of arch configuration, calcification, and associated atherosclerotic or thrombotic lesions. Patients with significant atherosclerotic and/or calcific disease of the arch should be excluded from a transfemoral approach to repair of an innominate, common carotid or carotid bifurcation lesion. Arch tortuosity is best assessed using the method described in Figure 21.1. An elongated or tortuous arch is common in elderly patients, especially those with a long history of hypertension.

INNOMINATE AND COMMON CAROTID ARTERY There are significant differences between interventions in the carotid bifurcation and those in the

common carotid and subclavian–axillary arteries. Most symptomatic carotid bifurcation lesions present as a result of cerebral embolization, and the potential for embolization with manipulation is probably higher than for lesions of the arch. Carotid bifurcation stent placement is performed with some type of cerebral protection, almost always just a single self-expanding stent, and is performed with a 0.014 platform. Lesions of the innominate and common carotid arteries that require treatment occur less frequently than carotid bifurcation stenoses. Subclavian artery stenoses and occlusions are common but often they do not need to be treated. Innominate, common carotid, and subclavian lesions, compared with the carotid bifurcation, are less likely to present with embolization and are more likely to present with hypoperfusion syndromes. Inflow lesions of the innominate or common carotid arteries may require treatment prior to carotid bifurcation repair and lesions of the subclavian artery may require treatment prior to dialysis access placement or the occasional case of upper extremity bypass. These are usually treated without a cerebral protection device and may be managed with either a 0.014 or 0.035 system and with either selfexpanding or balloon-expandable stents. The most common disease to occur in the innominate, common carotid, and subclavian arteries that requires angioplasty and stent placement is disease that occurs at the origins of these arteries. These lesions tend to be heavily calcified. They also tend to occur at the origin of the artery where the location of the sheath for delivery of the stent is less stable. Lesions at the origin of the innominate, common carotid, and subclavian arteries are treated with balloonexpandable stents for accuracy of placement and crush resistance appropriate for highly calcified lesions. 275

276  Brachiocephalic interventions

Table 21.1  Supplies for interventions of the innominate, common carotid, and subclavian arteriesa Length Guidewire

Catheter

Starting guidewire Selective guidewire Exchange guidewire Flush catheter Selective cerebral catheter

Sheath Balloon

Cerebral guide sheath Balloon angioplasty catheter

Stentb

Balloon-expandable stent (premounted) Self-expanding stent (nitinol)

a b

Bentson Glidewire® Amplatz Super Stiff® Pigtail Vertebral (Vert) Headhunter H1 Vitek Simmons 1, 2 Shuttle or Destination Balloon diameter Balloon length Catheter shaft Stent diameter Stent length Shaft length Stent diameter Stent length Delivery catheter

Diameter

180 cm 0.035 inch 180 cm 0.035 inch (angled tip) 260 cm 0.035 inch 90 cm 5-Fr 100 or 125 cm 5-Fr 100 cm 5-Fr 125 cm 5-Fr 100 cm 5-Fr 90 cm 6-Fr or 7-Fr 5, 6, 7, 8, 9, 10 mm 2, 4 cm 120 cm 3-Fr or 5-Fr 6, 7, 8, 10 mm 15–35 mm 135 cm 8, 10, 12, 14 mm 20, 40 mm 120 cm

Excluding carotid bifurcation balloon angioplasty and stenting. No stents are approved by the FDA for routine usage in this vascular bed.

A detailed discussion of selective catheterization of these arteries can be found in Chapter 9. Chapter 11 covers arch aortography and selective branch vessel a­ rteriography. Supplies required for interventions of the innominate, common carotid, and subclavian arteries are listed in Table 21.1. Focal lesions of the common carotid artery are usually approached antegrade through a femoral access. In the situation of combined common carotid and bifurcation lesions requiring treatment, a hybrid procedure may be performed, which includes retrograde access through an open exposure to treat the common carotid artery lesion combined with carotid endarterectomy. Occasionally, retrograde access through a distal common carotid artery exposure is appropriate for treatment of a de novo common carotid artery origin lesion in a patient with severe arch disease or in conjunction with stent–graft placement for arch or thoracic aortic disease. Arch aortography is performed through a femoral approach using a pigtail catheter and a pressure injector, as described in Chapter 11. The image intensifier is best placed in the left anterior oblique (LAO) position (see Chapter  9, Figure 9.1). An image of the arch, the origins of its branches, and

the carotid bifurcation is saved on the monitor and the image intensifier is not moved until the artery origin is cannulated. It is best to include within the image the mid-ascending aorta on the bottom of the field and the carotid bifurcation on the top of the field.

ASSESSMENT OF ARCH BRANCH LESIONS Because these lesions are typically at the origins of the arteries and are associated with the arch of the aorta, imaging of the arch must be performed in order to fully understand the extent of lesions in these locations. Arch aortography in the LAO position is one way to evaluate the origins of the innominate, left common carotid, and left subclavian arteries. To visualize the innominate bifurcation, which includes the origins of the right subclavian and right common carotid arteries, a right anterior oblique (RAO) projection is usually required. If there is associated disease in the arch of the aorta or lesions in middle segments of the arch branches, it may influence catheter placement in an effort to avoid the worst part of the disease and avoid embolization as a result of encountering

Principal techniques  277

A

B

Fig. 21.1  Arch assessment. (A) Normal aortic arch in segments. The branches generally originate from the “top” or superior aspect of the arch. All the branch origins are a substantial distance superior to the horizontal line drawn across the upper, inner aspect (the inner curve) of the arch. (B) An elongated arch, which is common in the elderly and those with hypertension. A line drawn across the upper inner aspect of the arch readily demonstrates that the origin of the innominate artery is inferior to the line. If the arch branch is inferior to or near this line, catheterization will be more challenging, may require more attempts, and the arch branch origin may be resistant to sheath placement.

arch disease. The arch and its proximal branches may also be assessed using MRA or CTA. These are useful for planning the access and approach, but are somewhat limited in accurate assessment of lesion severity since they tend to overemphasize the degree of stenosis. In addition, CTA tends to overemphasize the calcium and these lesions are generally heavily calcified. Both methods are very helpful at delineating the anatomy of the area. Prepare for the case by assessing the length of the disease to be treated and choosing the stent that is most likely to be used during the procedure. Placement of stents using a transfemoral approach will require a 70-cm sheath in a short person and a 90-cm sheath in a normal sized to tall person. If there is significant calcium in the aorta, it may influence the type of catheter. A simple curve catheter choice for crossing these lesions includes a vertebral catheter and, for a complex curve catheter, a Vitek catheter is frequently useful since it may be pushed into the arch from the descending aorta rather than dragged backward from the right side of the arch to the left side of the arch. There is a choice with arch branch lesions as to whether a small caliber (0.014- or 0.018-inch) or a 0.035-inch diameter system would be best. In addition, with respect to the planning and treatment of subclavian lesions, it is quite often valuable to approach these lesions for either part of or all of the treatment by

using a brachial access, and this is discussed later. This, however, should be decided, to the best extent possible, at the beginning of the procedure.

PRINCIPAL TECHNIQUES Access is obtained in the femoral artery. Systemic anticoagulation is administered. A 5-Fr or 6-Fr sheath is placed in the femoral artery and a 100cm length 5-Fr pigtail catheter is advanced so that the head of the catheter is in the ascending aorta. Arch aortography is performed. This demonstrates the location of the lesion as well as its length and approximate diameter. Subsequently, a Glidewire® is passed through the pigtail catheter and the catheter is removed. An angled catheter, usually a simple curve catheter or a vertebral catheter, is advanced over the Glidewire®. The Glidewire® is withdrawn into the shaft of the catheter. The catheter is then withdrawn slightly and pointed toward the location of the lesion at the artery origin that is intended for crossing. The so-called “no touch” technique is used if possible. The catheter is pointed in the appropriate direction. Occasionally, a puff of contrast may be used to assist visualization. The guidewire is used to gently probe the roof of the arch to feel for the lesion and to get across the lesion. After the Glidewire® has crossed the lesion, it is then advanced into the mid-distal

278  Brachiocephalic interventions

common carotid artery. If possible, the simple curve catheter is advanced over the Glidewire® and the carotid artery is road mapped to identify the location of the carotid bifurcation to avoid inadvertently crossing it if crossing the bifurcation is not required. Subsequently, a 0.035-inch diameter stiff exchange wire is advanced through the catheter. The tip of the exchange wire is placed in a way that is consistent with the degree of tortuosity through which the sheath must pass. The tip of the wire is usually placed in the distal common carotid artery. For a tortuous arch, it may require placement in the distal external carotid artery. This way, there is more stiff wire distal to the arch to create a better rail. The sheath is then advanced over this system with the stiff exchange wire. Be careful to not inadvertently advance the tip of the dilator for the sheath across the lesion if this is not planned. At some point, the dilator is held steady and the sheath advanced over the dilator to achieve the last couple of centimeters. If the planned procedure is to take place using 0.035-inch compatible balloon catheters and stent delivery catheters, the same stiff guidewire is maintained in place and used for treatment. If it is desirable to switch to a 0.014-inch-based system, then this is the time to do so, after the sheath is in place. Lesions distal to the origin of the arch branch may be treated by placing a stiff 0.014-inch ­ diameter guidewire wire into the external carotid artery. Lesions at the very origin of the arch branches leave no place within the branch artery to put the sheath tip to make a stable system. A 0.014-inch diameter guidewire is not as sturdy as a 0.035-inch diameter guidewire. Because of the location of the lesion at the origin of the artery, the only way to obtain a stable sheath position and get the sheath close enough is to put the tip of the sheath up close to the lesion using a fairly heavy exchange guidewire. The lesion may be predilated and then stented or managed with primary placement. This is a judgment call. Primary stent placement requires one less step and one less opportunity to challenge the stability of the system. However, when using a 0.035-inch system, the caliber of the premounted stent may be too large to cross a tight lesion without predilation. A premounted, balloon-expandable stent is advanced over the guidewire and then advanced across the lesion. Small puffs of contrast may be administered to help position it. Just before

placement of the stent, the sheath must be withdrawn slightly so that the lower end of the stent is able to clear the upper end of the sheath when the stent is expanded. When the sheath is withdrawn, it creates an inherently less stable situation, so care must be taken to maintain the guidewire position without any withdrawal of the wire and to line up and deploy the stent without wasting time. The advantage of the 0.035-inch system in this case is that this is a sturdier platform. The disadvantages are that the wire manipulation is quite limited and also that the stent delivery catheter fills the sheath and a larger sheath is required to maintain the ability to inject contrast around the stent delivery catheter in order to perform adjustments in position prior to deployment. Ventilatory motion and arch movement with the cardiac cycle make this fine tuning of position necessary. The capability should be maintained so that contrast can be administered in small puffs through the sheath to confirm the optimal placement of the stent prior to deploying it. A lesion in the mid-common carotid artery may also be encountered that is not at the common carotid artery origin. Because this is a relatively mobile artery, if the lesion does not involve the origin of the common carotid artery and there is a length of at least 1 cm of reasonably sized and nondiseased artery at the origin of the common carotid artery, an option in this case is to use a self-expanding nitinol stent. Although the trailing end of the stent is difficult to place with a high degree of accuracy, if there is a centimeter of open space in the artery distal to its origin, this is usually adequate. With respect to the innominate artery, sizing issues are often a problem. Because the artery is somewhat short and there is often a calcified origin lesion, placement of a self-expanding stent is not advisable and a balloon-expandable stent should be used. The innominate artery is larger in diameter than the other arch branches and the balloon-expandable stent must have a diameter of 10 mm or more and is usually delivered through a sheath with a larger crossing profile, which must be placed across the lesion in order to place the stent. Imaging during stent placement should be determined by whether the lesion is directly at the origin of the blood vessel or located more distally close to the bifurcation. This is because the origin of the innominate artery is better visualized in the LAO

Transfemoral approach to the common carotid artery  279

position and the bifurcation of the artery is better seen in the RAO position of the image intensifier. The other concern with the innominate artery is that it is typically a very unstable place to have a sheath, especially when the origin of the artery is being treated. Because this is an unstable system, consider using a stiff guidewire that extends out into the right subclavian artery and can be placed all the way into the axillary artery if necessary to obtain more purchase and stability. Another way to obtain more stability is to place two separate 0.014-inch diameter guidewires, one into the common carotid artery and one into the subclavian artery, and then place a 0.035-inch compatible stent delivery catheter over the combination of the two wires. The combination of two different 0.014inch diameter guidewires is less than the diameter of a single 0.035-inch diameter guidewire. Most of these lesions can be treated using a transfemoral approach, but sometimes the adjunctive addition of a transbrachial approach is quite helpful. After stent placement a follow-up balloon angioplasty is usually performed. Care must be taken with placement of balloon-expandable stents to expand them adequately so that they are in a stable position, but not to overexpand them and cause injury to the artery and surrounding tissues. A completion arteriographic study is then performed through the sheath and if this is satisfactory, the guidewire and sheath are removed.

TRANSFEMORAL APPROACH TO THE COMMON CAROTID ARTERY In proceeding with a transfemoral approach to the common carotid artery, a guidewire and access sheath are inserted (Figure 21.2). Heparin is administered intravenously (75–100 U/kg). The tip of the guidewire is placed in the arch. A 6-Fr or 7-Fr, 90-cm long, straight sheath with a radiopaque tip is passed and the tip advanced to within a few centimeters of the origin of the artery. The operator must decide whether to lead with the guidewire or with the catheter. If the lesion is located at the very origin of the common carotid artery, either the catheter or the guidewire may be used to lead. Neither of these is optimal to lead because they will be protruding from the end of the sheath, which is mobile within the arch, and this is a relatively unstable position for the whole platform. If the lesion is distal to the origin of the vessel, lead

with the catheter to cannulate the artery and then advance the guidewire. The appropriate selective cerebral catheter, 100–120 cm in length, is placed through the sheath. The head of the selective cerebral catheter extends beyond the end of the sheath. The cerebral catheter directs the guidewire into the origin of the common carotid artery. The steerable guidewire is advanced carefully beyond the common carotid artery lesion and into the external carotid artery. The cerebral catheter may be advanced over the guidewire and into the external carotid artery. The steerable guidewire is exchanged for an Amplatz Super Stiff® guidewire or other long exchange guidewire. After the stiff guidewire is in place in the external carotid artery, the cerebral catheter is removed. The dilator is replaced within the long sheath and the sheath is advanced carefully up to the artery origin. Avoid dottering the lesion with the dilator. It is usually best to advance the sheath directly over the dilator for the last few centimeters. After the tip of the sheath is in place, additional arteriography and heparin flushing may be performed through the side arm of the sheath. The long sheath should be flushed regularly and care must be taken to avoid thrombus formation or microbubbles. Carotid arteriography is performed through the sheath with a small field of view. The usual diameters are 6–8 mm for the common carotid artery and 8–12 mm for the innominate artery. The most favorable lesions are focal and a 2-cm long balloon is usually adequate. Usually, primary stent placement is performed. Orifice lesions are best treated with a balloon-expandable stent. Other lesions may be treated with either self-expanding or ­balloon-expandable stents, since these are relatively straight conduit arteries. Self-expanding stent diameter should be 8 mm for a 5–7 mm common carotid artery or 10 mm for a 7–9 mm artery. The stent delivery catheters must be 120 cm. The length of the stent should be kept to a minimum. The stent delivery catheter is passed over the guidewire, through the sheath, and into position across the lesion (Figure 21.3). The stent is deployed and postplacement dilation is performed, followed by completion arteriography. In each case, the sheath is close to the lesion and it is withdrawn to uncover and deploy the stent. If landmarks require rechecking, contrast may be injected through the sheath prior to stent

280  Brachiocephalic interventions

A

B

D

E

F

G

C

H

Fig. 21.2  Balloon angioplasty of the common carotid artery. (A) Arch aortography is performed with a flush catheter. (B) The guidewire is replaced after the location of the common carotid artery origin and the lesion is identified. (C) A long sheath is placed in the proximal descending aorta. (D) A selective cerebral catheter is advanced through the sheath and used to cannulate the common carotid artery. The catheter must be at least 20 cm longer than the sheath. (E) The guidewire is directed into the external carotid artery. (F) The sheath is advanced into the proximal common carotid artery and an arteriogram is obtained. (G) Balloon angioplasty is performed. If the lesion is in proximity to the bifurcation, the guidewire should be placed in the internal carotid artery. (H) Completion arteriography is performed through the sheath.

deployment. Afterward, completion arteriography may likewise be performed through the sheath. Orifice lesions require a very high degree of placement accuracy since the proximal end of the stent should protrude into the arch enough to contain any arch plaque that has spilled over into the common carotid artery. Orifice lesions may also

be challenging from a femoral approach because when the sheath is pulled back to expose the stent, the tip of the sheath loses its purchase on the origin of the common carotid artery. The sheath must be withdrawn carefully and the tip should be parked as close to the end of the balloon as possible without impinging on it. After deployment,

Carotid bifurcation stent placement  281

A

B

C

Fig. 21.3  Stent placement in the common carotid artery. (A) After guidewire and sheath placement, an arteriogram is obtained. (B) A self-expanding or balloon-expandable stent is delivered to the site of the lesion or the angioplasty. (C) The stent is deployed while maintaining access to the common carotid artery with the sheath.

postdilation of both ends of the stent is performed using the same balloon.

CAROTID BIFURCATION STENT PLACEMENT Patient preparation for carotid bifurcation stenting includes clopidogrel (75 mg/day for 5 days prior to the procedure) and daily aspirin (325 mg). The aortic arch, carotid arteries, and cerebral arteries are evaluated prior to the stent procedure using arteriography, MRA, or CTA. Carotid bifurcation stenting may be performed using a transfemoral or a transcervical exposure, with a small number of patients being best served by an approach through the brachial or radial arteries. The procedure is performed under local anesthesia with minimal or no sedation to facilitate continuous neurologic monitoring. An arterial line is placed for continuous pressure monitoring and electrocardiography leads for cardiac monitoring. Temporary pacer

pads should be available and patients with aortic stenosis should have the temporary pacer pads in place. Antihypertensive medications may be withheld on the morning of the procedure, especially beta blockers. Bradycardia occurs frequently with balloon angioplasty of de novo carotid bifurcation stenosis due to carotid sinus nerve stimulation, and this may be sustained after the procedure. Femoral access is achieved and heparin administered (100 U/kg). An activated clotting time (ACT) is obtained and maintained at >250 seconds. The same size femoral sheath access sheath is placed as that anticipated for the procedure, usually either 6-Fr or 7-Fr. A floppy tip guidewire is placed in the aortic arch and the image intensifier rotated into the LAO position to reflect the best angle achieved for viewing, as identified on the preoperative study. The cerebral catheter of choice is placed over the guidewire. Chapter 9 offers a discussion of carotid catheterization and Chapter  11 discusses carotid arteriography. The image intensifier is maintained

282  Brachiocephalic interventions

in its fixed LAO position and the bony landmarks may be used to guide vessel cannulation. The cerebral catheter is placed in the common carotid artery origin. A hydrophilic, steerable guidewire is advanced through the catheter and into the mid- to distal common carotid artery. The location of the carotid bifurcation can often be identified on plain fluoroscopy due to the presence of vessel calcification. The guidewire is not permitted to pass into the

bifurcation. The cerebral catheter is advanced so that its tip is well seeded in the common carotid artery. A road map of the carotid bifurcation is performed (Figure 21.4). The position of the image intensifier may require adjustment to obtain the best image showing the bifurcation and the separation of the internal and external carotid arteries. Occasionally, a lateral view is required. Multiple views may be needed to best open the carotid bifurcation.

A

B

C

D

E

F

Fig. 21.4  Carotid bifurcation stent placement. (A) The left common carotid artery is catheterized and a road map is created of the bifurcation. (B) The Glidewire® is advanced into the external carotid artery and the catheter advanced. (C) The stiff exchange guidewire is placed in the external carotid artery. (D) The angiographic catheter is withdrawn from the external carotid artery. (E) The sheath is advanced over the stiff guidewire. (F) The tip of the sheath is placed in the mid- to distal common carotid artery. (Continued)

Carotid bifurcation stent placement  283

G

L

H

M

I

J

N

K

O

Fig. 21.4 (Continued)  Carotid bifurcation stent placement. (G) The exchange guidewire is withdrawn from the external carotid artery. (H) The leading wire for the distal embolic protection device is placed across the lesion. (I) The filter delivery catheter is passed across the carotid stenosis. (J) The filter is deployed. (K) Predilation of the lesion. (L) The stent delivery catheter is advanced. (M) The stent is deployed across the bifurcation. (N) Poststent dilation is performed, keeping the balloon within the stent and only dilating the area of residual lesion within the stent. (O) After completion angiography, the filter is removed.

The next step is selective cannulation of the external carotid artery. This is performed with a 260-cm angled Glidewire® advanced under road mapping and the cerebral catheter is advanced into the external carotid artery. When common carotid catheterization is performed with a simple curve catheter, advancement of the catheter into the external carotid artery is facilitated. When a complex curve catheter is used to cannulate the common carotid artery, it is sometimes possible

to advance the catheter into the external carotid artery. However, frequently, it must be exchanged for a simple curve catheter. An attempt should be made to reach as distally into the external carotid artery as possible. This allows adequate guidewire length beyond the bifurcation for subsequent placement of the carotid access sheath. The Glidewire® is withdrawn from the cerebral catheter and a 260-cm stiff exchange guidewire, such as an Amplatz Super Stiff®, is placed in the external

284  Brachiocephalic interventions

carotid artery. Before placing the exchange guidewire, check to make sure that there is backbleeding from the catheter. If the catheter has been advanced into a very small branch or if spasm has occurred and there is no backbleeding, the inner catheter surface may become lined with air bubbles. When the exchange guidewire is introduced, these microbubbles may be pushed into the cerebral circulation and become emboli. Occasionally, the catheter must be very slightly withdrawn to restore backbleeding. When the stiff exchange guidewire is advanced, it is usually best to position the image intensifier in the LAO position. The field of view should include the top of the arch on the inferior aspect of the monitor so that the last turn from the arch into the common carotid artery can be visualized as the stiff guidewire rounds the turn. Superiorly on the monitor, the tip of the catheter is visualized and its position established using bony landmarks. If there is significant arch tortuosity, the last turn from the arch into the common carotid artery may be a challenging angle. As the stiff guidewire enters the common carotid artery, it may start to pull the catheter down from the external carotid artery. If the tip of the catheter starts to migrate inferiorly, this serves as an early warning system that the catheter–guidewire apparatus has too much tension in it and that an alternative plan is required. After the stiff exchange guidewire is placed, the simple curve catheter is withdrawn leaving the stiff guidewire in the external carotid artery. The access sheath in the groin is removed. A 6-Fr or 7-Fr 90-cm sheath is advanced over the stiff guidewire into the common carotid artery. There are many sheath choices for this maneuver. Two good choices are the Flexor® Shuttle® Guiding sheath and the Destination® Peripheral Guiding sheath. As the sheath is advanced, image the distal end of the stiff wire in the external carotid artery, including the last turn exiting the arch and the tip of the guidewire. If the tip of the guidewire starts to back up, it indicates that the sheath is not advancing appropriately over the wire. The dilator tip for the carotid sheath is several centimeters longer than the sheath itself and could be inadvertently advanced into the bifurcation. The outline of the dilator tip can usually be identified under fluoroscopy even though it does not have a radiopaque marker. When the dilator reaches its desired location in the mid- or distal common

carotid artery, it is held steady and the sheath may be advanced over the dilator itself. After the sheath is in place, the dilator is withdrawn and carotid angiography performed through the sheath to be sure that the tip of the sheath is optimally placed. The tip of the sheath should be a minimum of 5–10 cm inside the common carotid artery so that the position of the sheath is stable. After the filter is deployed, if the sheath begins to back up, options for managing this are limited. The stiff guidewire is removed, and the image intensifier optimally positioned to road map the bifurcation. Some type of embolic protection is standard in CAS placement. Embolic protection may be performed using one of a variety of distal protection devices. Several distal filters are available and some examples are discussed in Chapter 20. There are also occlusive devices, which use a balloon for either proximal or distal occlusion. The filter may be either a free wire or fixed wire system. Either way, the tip of the 0.014-inch guidewire is shaped appropriately to aid access to the internal carotid artery. After crossing the stenosis, the tip of the guidewire is placed close to the skull base but not into the intracranial portion of the artery. It is important to avoid advancing the tip of the guidewire any further. The intracranial portion of the carotid artery is prone to dissection with guidewire manipulations. The image intensifier position is then set, with the tip of the sheath visible at the lower margin of the view, the bifurcation in the middle, and the tip of the guidewire on which the filter is based located at the upper end of the field of view. After the guidewire is placed across the lesion, the filter is rapidly deployed. The length of the filter and the location of the stenosis must be taken into account. Each filter requires an appropriate landing zone, preferably in a straight and nondiseased artery segment at least 2 cm distal to the location intended for the upper end of the stent. This requirement may also influence filter selection. The lesion is predilated with a 3-mm ­diameter, monorail-based, 2-cm or 4-cm length balloon. ­ Prior to specific events, such as predilation, stent placement, or poststent balloon angioplasty, small doses of atropine (0.25–0.50 mg each time) or other vagolytic should be administered intravenously to prevent or blunt the bradycardic response that may occur. The duration of the predilation depends on the appearance and behavior of the balloon but is

Carotid bifurcation stent placement  285

usually kept as short as possible. The predilation balloon is inflated only once and the inflation time varies depending on the lesion. The purpose of predilation is to create a safe tract for the stent delivery catheter. Some operators practice “primary stenting” without predilation on a regular basis. However, with any significant stenosis, a 6-Fr stent delivery catheter will have a dottering effect on the lesion unless predilation is performed. Carotid bifurcation lesions may be treated with any one of the variety of self-expanding stents that are available for use in this position. The stents vary from 2 cm to 4 cm in length. The stents may be open cell or closed cell. Most available stents are constructed of nitinol, may be tapered or tube structure, and vary from 6 mm to 10 mm in diameter. The stent diameter is selected based on the largest diameter that must be fitted to the stent, usually that of the common carotid artery. The self-expanding stent is deployed using road mapping. It is postdilated with a 5 mm × 20 mm balloon over a 0.014-inch wire, depending on the size of the internal carotid artery. This is usually easily performed by placing the balloon in the location where any residual stenosis is seen to be crimping the stent. A 5-mm balloon percutaneous transluminal angioplasty (PTA) is often adequate; rarely is a 5.5- or 6-mm PTA required post stent deployment. A mild or even moderate residual stenosis may be acceptable, as the selfexpanding stents continue to expand with time. The risks of overdoing it with poststent balloon dilation include embolization of plaque contents, severe bradycardia and hypotension, balloon rupture, and, very rarely, vessel rupture. The balloon used for poststent PTA is always maintained within the stent and does not extend to the native artery. This is usually simple since carotid bifurcation lesions are focal and the artery proximal and distal to the lesion tends to be healthier and of nominal diameter. Nominal pressure is used to fully expand the balloon and the stent, and it is not kept inflated any longer than necessary. High pressures are not used. In the majority of cases, the stent is placed across the bifurcation into the common carotid artery, crossing the origin of the external carotid artery. Occasionally, with poststent angiography, some flow of contrast is visible outside the stent profile and into an ulcer. No attempt should be made to obliterate this by using larger balloons or higher

pressures as this almost always smooths out in the ensuing weeks and is usually of no consequence. There should also be flow of contrast outside the stent at the location of the origin of the external carotid artery. Patients with >2-cm long carotid lesions, dense calcification (seen on plain fluoroscopic images), and large ulcerated plaques are at higher risk for complications of CAS placement. Tortuosity of the common carotid artery, bifurcation, or, more commonly, the distal internal carotid artery may be challenging to manage during CAS placement. Tortuous inflow causes problems in creating and maintaining a safe and stable access. Kinks and bends near the lesion and in the distal internal carotid artery may pose a problem with stent implants. As the carotid bifurcation lesion narrows and plaque thickens and hardens, it frequently leads to a lengthening of the segment where the disease is worst. Consequently, at the location where the lesion ends and the artery is soft, there is often an efferent turn out of the lesion that is quite angulated or even kinked. Tortuosity cannot be removed, only transferred to another location. As a stent is placed that partially straightens a curved or kinked segment, another segment juxtaposed to the stented location usually becomes more tortuous. Deploy stents across bends only if they are isolated and only when necessary. Avoid placing the distal end of the stent into kinks and tortuosities of the internal carotid artery if more than a single bend is noted. A very tortuous internal carotid artery should be considered a relative contraindication for CAS placement. The filter is removed only after an arteriogram has confirmed forward flow through the filter and no filling defect in the stent or filter. If there is slow flow or a large amount of debris in the filter, consider using an over-the-wire aspiration catheter to remove this material. The filter is removed and final angiograms are acquired in the projection that had demonstrated the maximum stenosis. Attention is paid to the internal carotid artery immediately cephalad to the stent. Spasm in this segment may be encountered. The best treatment for internal carotid artery spasm is to finish the case and remove the distal protection device. A small dose of intra-arterial nitroglycerine (50–100 mcg) is directly administered into the artery. Post-CAS placement intracranial angiograms are obtained by many operators as a routine. The sheath is then removed.

286  Brachiocephalic interventions

Patients are monitored overnight for cardiac and neurologic problems. It is not uncommon, especially in patients with a history of coronary artery disease, to have a heightened response to carotid sinus distension. It may require inotropic support for a time before the carotid sinus adapts to the radial force of the self-expanding stents. Avoiding extreme oversizing of the stents helps to decrease the incidence of post-CAS placement bradycardia and hypotension. The presence of significant hypotension in the absence of bradycardia is unusual in the immediate postprocedure period; it is worth emphasizing that other causes (e.g., retroperitoneal bleed related to access site problems) should also be excluded as the cause. Medications include aspirin (325 mg each day indefinitely) and clopidogrel (75 mg each day for 1 month). Follow-up includes duplex scan at intervals, as is performed after carotid endarterectomy.

OPEN CELL, CLOSED CELL, AND MESH COVERED CAROTID STENTS (FIGURE 21.5) Both open cell stents and closed cell stents are available for treatment of carotid bifurcation stenosis. Self-expanding nitinol stents can be viewed as a series of rings with an oscillating pattern, which are connected together to form a wire mesh tube. Open cell stents have connections between A

B

only some of the rings that the stent comprises. This allows the open cell stent to be significantly more flexible than other stents. It also means that the cells or openings of the stent are significantly larger than closed cell stents. When an open cell stent goes around a tortuous segment, some of the cells on the outside curvature of the bend will likely be quite large in comparison to the usual size of the cell if the stent is maintained in a straight position. Closed cell stents provide more outward force and crush resistance. They are usually easier to visualize fluoroscopically because they contain more metal. At each of the apices of the wire crossings, the rings are typically connected. This leads to much smaller cells and much more metal coverage of the lesion. There is some data to suggest that closed cell stents could provide better results, especially in symptomatic patients, by providing more metal coverage of the carotid lesion. This may permit fewer emboli and provide better scaffolding of the lesion. Most of the data that suggest this possibility are nonrandomized, so may suffer from patient and lesion selection bias. Nevertheless, there is a common sense idea that more lesion coverage is better, and there is no evidence to suggest that closed cell stents are associated with more restenosis than open cell stents. Taking that concept a step further is the idea of a mesh covered carotid stent that would make the C

Fig. 21.5  Relative differences between open cell, closed cell, and mesh covered carotid stents. (A) Design of a typical open cell stent. The stent is made of nitinol rings. The rings are bridged over every few oscillations. This pattern of connection provides more flexibility but also leaves larger spaces between the stent struts. (B) Design of a typical closed cell stent. The separate rings of nitinol are connected at every possible juncture. This creates better outward force and crush resistance and better visibility due to the increased amount of metal. However, these stents are not as flexible. Because there is more metal and the cells are smaller, closed cell stents provide more scaffolding and more coverage of the lesion. (C) Mesh covered stent. The backbone is typically a very open cell, nitinol frame covered by a mesh. This creates much smaller pores and much more extensive lesion coverage. The mesh may be constructed of nitinol, PET, or PTFE.

Distal and proximal protection devices for transfemoral carotid stenting  287

spaces in the coverage even smaller. Several different mesh covered carotid stents are in clinical trials. The mesh may consist of nitinol, polyethylene terephthalate (PET), or polytetrafluoroethylene (PTFE). The theoretical advantage would be to provide the smallest possible cells through which an embolus could occur and still maintain the patency of the external carotid artery. The potential disadvantages are a slightly larger caliber delivery of the mesh covered stent and also the potential that the mesh will take up some of the lumen and result in a higher degree of residual stenosis or increased recurrent stenosis. Data so far show that the external carotid artery generally maintains its patency. The mesh covered stent may make a significant contribution to endovascular management of carotid disease in the future.

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DISTAL AND PROXIMAL PROTECTION DEVICES FOR TRANSFEMORAL CAROTID STENTING (FIGURE 21.6) Most of the protection devices in the carotid stent trials so far have been performed using distal filters as the cerebral protection device. There are several different filters that have been approved for use and been well studied. Many resemble an umbrella or a badminton birdie. These filters are mounted on a wire and must be placed across the lesion prior to establishing protection. Filters typically comprise of a nitinol scaffolding and a porous covering over the “top” of the umbrella. When a filter is unsheathed, the filter opens. The filter must be placed in a segment distal to the lesion. Therefore, a

C

Fig. 21.6  Methods of cerebral protection for transfemoral carotid stent placement. (A) Distal protection filter. The filter is mounted on a wire. The filter must cross the lesion in its constrained state and then be unsheathed and opened in the distal internal carotid artery distal to the lesion. This requires a filter landing zone. The filter must be opposed to the wall for it to work as well as possible. The filter illustrated is a fixed wire filter because it is mounted directly on the wire. If the wire moves, the filter moves. (See text for description of free wire systems.) (B) Distal occlusion balloon. The balloon is mounted on a wire. The wire is actually a hypotube, which can be used to inflate the balloon and stop antegrade flow into the internal carotid artery distal to the lesion. The crossing profile of this device is typically less than that of a constrained filter. This is not commonly used in the US but is used in many countries. (C) Mo.Ma™ Ultra proximal protection device. The sheath is slightly larger at 8-Fr. It has a balloon mounted on its tip, which can be inflated to stop flow from the common carotid artery and into the bifurcation. There is also a catheter that connects to a smaller balloon, which is used to occlude the external carotid artery. The remaining lumen of the sheath is then used to perform carotid angioplasty and stenting. The bifurcation is aspirated before flow is restored into the internal carotid artery.

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relatively straight segment of artery must be present for a filter landing zone. The filter must be placed far enough distal to the lesion that the stent can be placed with its superior end extending beyond the lesion into healthier distal artery without encountering the filter. If the artery distal to the lesion is very tortuous, it may not be possible to place the filter. Once the filter is in place, the goal is not to move it during the time that the angioplasty and stenting of the carotid lesion is being performed. After the lesion has been treated, a filter capture catheter is passed through the fully opened carotid stent to capture the filter. When the filter is captured, if there is significant debris within the filter, an attempt is made to close the nitinol loop that supports the filter without squeezing the entire filter into the capture catheter. This provides some room for debris in the filter to prevent it from being released into the circulation. Spasm can occur at the location where the filter is resting just distal to the lesion, and the operator should be ready to administer a vasodilator if this is the case. If the filter is full, an aspiration catheter can be used on the wire prior to filter retrieval to remove some of the debris from the area. This is especially the case if the filter is so full that flow through it is impeded. Filters may be fixed to the wire (fixed wire system) or may be floating on the wire (free wire system). Either system can be used in most carotid stent procedures. With a fixed wire system, whenever the wire moves, the filter also moves. The free wire system permits the wire to cross and the filter to be advanced over it. This may have an advantage over the fixed wire system in patients with tortuosity to facilitate filter crossing. Free wire systems are preferred in the lower extremity where more wire movement is expected. Some of the free wire systems that are used for distal protection are demonstrated in Chapter 20, Figure 20.14. A Mo.Ma™ Ultra proximal protection device includes a common carotid artery occlusion balloon on the tip of the sheath and a catheter in the external carotid artery. The proximal occlusion balloon on the tip of the sheath stops forward flow through the common carotid artery. The external carotid artery occlusion balloon prevents flow coming in a reverse manner from the external carotid to the internal carotid artery. After the external carotid artery balloon and proximal common carotid artery occlusion balloon are in place, flow through the carotid bifurcation is stopped.

Under cessation of flow, the carotid stent is placed. After  the stent is placed, the carotid bifurcation and the stented segment are aspirated of debris. When this is done, the balloons are released and flow is restored.

TRANSCERVICAL APPROACH TO CAROTID STENTING (FIGURES 21.7–21.9) Transcarotid artery revascularization (TCAR) provides an alternative method of access and protection for carotid artery stenting. TCAR offers the potential of avoiding the aortic arch, establishing protection prior to wire crossing, and more efficient particle capture during the carotid stent procedure. Particle capture by distal filters appears to be inadequate. This is based on a number of MRI studies of the brain, which show that the appearance of new cerebral white matter lesions after transfemoral, distal filter-mediated carotid stenting is substantially more than is seen with carotid endarterectomy. In addition, studies of TCAR have shown that a significant minority of the strokes associated with the procedure occur in the contralateral hemisphere. During proximal protection with common carotid artery balloon occlusion there are also strokes that occur in the contralateral hemisphere. This suggests that the arch of the aorta may be a significant source of strokes. In addition, both of these protection maneuvers require significant manipulation of the bifurcation prior to establishing protection. In the TCAR approach, the proximal common carotid artery is accessed through an open cutdown and proximal protection is achieved with a clamp on the common carotid artery and a reversed flow circuit with flow into the femoral vein. The procedure may be performed under local or general anesthesia. A short, approximately 1-inch (2.5 cm) incision is performed, usually transverse and just superior to the clavicle. The dissection is carried down through the platysma and in between the sternal head and the clavicular  head of the ­sternocleidomastoid muscle. It is usually best to dissect between the muscle heads rather than divide them. The jugular vein is identified and retracted laterally. The common carotid artery is usually just deep to the jugular vein. The common carotid artery is  identified  and  dissected  out.  A  5-0  prolene

Transcervical approach to carotid stenting  289

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Fig. 21.7  Transcervical exposure of the proximal common carotid artery for a TCAR procedure. (A) A short transcervical incision is created between the sternal head and clavicular head of the sternocleidomastoid muscle. The patient is positioned such that the neck is extended and the head turned to the opposite side. The position of the incision is confirmed, using ultrasound, prior to making the incision. An ultrasound probe is placed over the area in question to find the shortest route to the common carotid artery. Almost always, this is between the two heads of the sternocleidomastoid muscle. (B) After the transverse incision is created, the platysma is divided. The muscle bellies of the clavicular head and the sternal head of the sternocleidomastoid muscle are identified. The space in between the muscles is developed. The clavicular head of the muscle is retracted laterally and the jugular vein typically lies directly over the common carotid artery. Care must be taken to avoid vagus nerve injury, as it may be located anywhere within the carotid sheath. It is almost always deep to the area of dissection. The vein is retracted laterally to expose the common carotid artery. (C) The common carotid artery is dissected free of surrounding tissue and looped. A 5-0 prolene purse-string or U-shaped suture is placed in the anterior wall of the common carotid artery where the sheath will be placed.

purse-string suture is placed along the anterior wall of the artery at the location where the sheath access will be placed. A small self-retaining retractor is usually helpful. Anatomic specifications require that the distance between the clavicle and the carotid bifurcation lesion should be 5 cm or more. If the patient has a very thick neck or a deep neck, a distance of more than 5 cm is better. A sheath is placed in the femoral vein, usually on the side contralateral to the carotid lesion to make logistics simpler. A reversed flow circuit is created between the common carotid artery and the femoral vein. A micropuncture needle is placed in the middle of the location of the purse-string suture in the proximal common carotid artery, and a micropuncture guidewire is inserted, which is measured prior to insertion to avoid encountering the bifurcation. A micropuncture catheter is inserted into the artery for 1–2 cm and an arteriogram obtained.

If the runway to the lesion is quite short, the wire is advanced into the external carotid artery and a short specially designed exchange guidewire placed in the external carotid artery. If the distance to the lesion is longer (i.e., more than 5 cm from the puncture site), a stiff exchange wire with the atraumatic tip can be placed in the distal common carotid artery proximal to the lesion. A specially designed sheath is inserted over the short exchange wire. The sheath is larger (8-Fr) so that a reversed flow circuit can be achieved while bifurcation stenting is being performed. The sheath has an external stopper on its shaft so that the tip of the sheath only goes approximately 2 cm into the artery. After the sheath is inserted, the exchange wire and dilator are removed. The sheath is secured in place. This must be performed carefully since the sheath tip is only inside the artery by 2 cm.

290  Brachiocephalic interventions

A

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Fig. 21.8  Establishment of a reversed flow circuit with common carotid artery clamping. (A) A contralateral femoral vein sheath is placed. (B) A micropuncture needle is inserted 1–2 mm into the artery at the center of the purse-string suture on the anterior wall of the common carotid artery. The micropuncture guidewire is advanced so that it extends into the artery only 2–3 cm. The micropuncture sheath is passed over the wire and an arteriogram obtained that demonstrates the location of the bifurcation and also the distance to the lesion. An exchange wire is inserted either into the external carotid artery or the distal common carotid artery. The sheath is advanced over the exchange wire. (C) From the common carotid artery sheath, a reversed flow circuit is placed. The circuit includes a flow modulator, which allows stopped flow, slow flow, or high flow. Distal to the flow modulator there is a filter, which will contain any debris that is released and removed from the carotid bifurcation. The flow circuit is plugged into the venous sheath and reversed flow is confirmed. (D) When the procedure is ready to be performed, a proximal common carotid artery clamp is placed.

The sheath tip has a slightly curved shape to it so that it conforms easily to the shape of the carotid artery. After the sheath has been secured, the reversed flow circuit is established. The reversed flow circuit has a flow modulator that allows flow to be regulated (stopped flow, slow flow, or high flow)

at the press of a button. The circuit also contains a filter that can be examined after the procedure for any particulate. Heparin is administered prior to accessing the carotid artery. The ACT is elevated to 250 seconds or more. After the arterial sheath is placed and the

Transcervical approach to carotid stenting  291

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Fig. 21.9  Carotid stent placement using a TCAR approach. (A) After the proximal common carotid artery clamp is placed, flow reversal in the circuit is confirmed. Flow reversal brings oxygenated blood into the ipsilateral hemisphere through collaterals using the process of entrainment. At this point it is safer to place a guidewire across the internal carotid artery stenosis since flow through the carotid artery is reversed. (B) While the flow is reversed, a predilation balloon is inserted to create a space for stent placement. The same hemodynamic effects of any angioplasty and stenting procedure of the carotid bifurcation should be expected, including hypotension and bradycardia. (C) The carotid stent is placed through the sheath and into the usual position, with continuation of reversed flow. (D) After stent placement, the wire is removed and flow reversal maintained for a few minutes. After that the common carotid artery clamp is removed, the sheath may be safely removed, and the common carotid artery purse-string suture is tied.

reversed flow circuit is in place, reversal of flow in the circuit is confirmed. The proximal common carotid artery clamp is then placed, proximal to the sheath. Oxygenated blood from collaterals is entrained to serve the ipsilateral hemisphere. This also allows very thorough removal of debris during the stenting process. If the lesion is very near the tip of the sheath, a 0.014-inch atraumatic guidewire is placed across the lesion. A standard predilation angioplasty is performed and a carotid stent placed. A stent system on a shorter shaft has been approved by the FDA, and this can also be used to improve the ease

of use of the procedure. With each angiogram, the flow can be stopped. The contrast is gently administered and the bifurcation visualized. By releasing the stop button immediately after visualizing the lesion, the injected contrast material can be removed by flow reversal. After the stent is placed, it is common to permit reversed flow for a period of time afterward. This allows for more complete flushing and removal of particulate. The transcervical approach to CAS placement has the same hemodynamic effects as transfemoral stenting and is often followed by hypotension and/or bradycardia.

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RETROGRADE APPROACH TO THE COMMON CAROTID ARTERY Common carotid artery lesions may also be approached retrograde, through open exposure of the mid- or distal common carotid artery. This approach is usually best in the following circumstances: angulated arch anatomy or arch disease that is not favorable for an antegrade approach; or a combined carotid bifurcation lesion that requires simultaneous endarterectomy (Figure 21.10). The two key factors for consideration in this approach are the very short working room between the access and the lesion and the need to clamp the carotid for a short period of time without options for a shunt. Common carotid artery exposure is performed through a short incision and the artery is looped. Heparin is administered. It is usually best to place a transfemoral pigtail catheter in the arch of the aorta for arteriography, even if the intervention is to be performed retrograde. This is because retrograde carotid arteriography is suboptimal at delineating the origin of the artery, especially in the setting of an orifice lesion. The image intensifier is placed in the LAO position to best demonstrate the separation between the common carotid or innominate arteries and the other arch branches. In situations where open exposure is performed for treatment of an isolated arch branch lesion, a 5-0 Prolene® purse-string suture is placed in the anterior surface of the common carotid artery. The artery is punctured as distally along the common carotid artery as possible but in a location that allows clamping and avoids any bifurcation disease. This helps to maximize working room between the access site and the lesion. The approximate distance can be measured on pretreatment CTA and an appropriate short sheath with a radiopaque tip can be selected. A short micropuncture needle (4-cm length) with a directable guidewire is useful here. The wire is inserted through the needle, and fluoroscopy is initiated immediately since the lesion will be encountered within a few centimeters. After the guidewire is across the lesion, steer it into the descending aorta. The natural tendency is for the guidewire to direct itself into the ascending aorta. The ascending aorta can only accommodate a short length of wire before it encounters the aortic valve. A short, bent tip selective catheter, such as a 40-cm long Kumpe catheter, is used to

direct the guidewire into the descending aorta. A very short access sheath, preferably 8 cm or less, is placed in the retrograde position. A retrograde arteriogram is obtained. If the proximal common carotid artery lesion is preocclusive or critical in severity, it may not be possible to accurately identify the origin of the artery using a retrograde contrast injection. Alternatively, consider an arch aortogram through a transfemoral pigtail catheter. The appropriate balloon and stent are selected and placed. The diameter of the common carotid artery can be measured on preoperative imaging studies and the appropriately sized premounted, balloonexpandable stent is prepared ready for insertion. The distal common carotid artery may be clamped during balloon angioplasty and stent placement as a form of distal protection. The artery is flushed and repaired after intervention. A hybrid procedure that combines simultaneous inflow stenting of the common carotid artery and carotid bifurcation endarterectomy is shown in Figure 21.10. Some additional maneuvers include the following steps. The carotid bifurcation is exposed and prepared as usual for endarterectomy. After anticoagulation, the internal and external carotid arteries are clamped. The micropuncture needle is placed in the common carotid artery at the location where the proximal end of the carotid arteriotomy is intended. The common carotid stent is placed as described in the section above. After completion arteriography, the guidewire is removed. The sheath is removed and the common carotid artery immediately clamped proximal to the arteriotomy site. The access site is used to begin the longitudinal carotid arteriotomy. After the artery has been opened in the usual manner, a shunt may be inserted as needed. The endarterectomy is performed in the usual manner.

THE SUBCLAVIAN AND AXILLARY ARTERIES Subclavian and axillary artery lesions can be approached antegrade (femoral artery access) or retrograde (brachial or radial artery access). The best candidates for this procedure have symptomatic vertebrobasilar insufficiency or upper extremity ischemia and a lesion that does not involve the origin of the vertebral artery. CTA of the arch is useful for planning the approach to subclavian artery lesions. The most commonly treated lesion

The subclavian and axillary arteries  293

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Fig. 21.10  Retrograde approach to the common carotid artery and hybrid approach to tandem carotid lesions. (A) The patient has tandem lesions of the carotid artery, including a proximal common carotid artery stenosis and a carotid bifurcation stenosis. (B) There is typically only a short distance between the two lesions. These may be repaired using an open approach (inflow bypass plus carotid endarterectomy), an endovascular approach (stent placement at the common carotid artery and the carotid bifurcation), or a hybrid approach (stent placement in the proximal common carotid artery and carotid endarterectomy). (C) The carotid bifurcation is prepared for open surgery. At the location where the proximal end of the arteriotomy would usually be located, a needle is placed in a retrograde direction. (D) The guidewire is placed and a 6-Fr short sheath with a bright tip inserted. The internal carotid artery is clamped prior to sheath placement. The wire usually extends toward the aortic valve. If desired, the wire must be directed into the descending aorta to avoid passing it through the aortic valve. (E) A balloon-expandable stent is placed in the proximal common carotid artery. (F) The wire is removed. The internal and external carotid artery clamps are left in place. The sheath is removed and the common carotid artery cross-clamped. The access site is used to initiate a longitudinal arteriotomy for standard endarterectomy.

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is a stenosis or occlusion near the origin of the left subclavian artery. The planning varies depending on whether the lesion is on the patient’s right or left side and whether it is located at the origin of the artery or a location more distal.

Transfemoral approach to the subclavian and axillary arteries A 6-Fr or 7-Fr sheath is placed in the femoral artery. Arch aortography is performed to identify the location of the subclavian artery. Very often, if the lesion is near the origin of the left subclavian artery, it can also be located by looking for its positional variation with pulsatility, while observing with fluoroscopy. If the lesion is on the patient’s left side, a LAO projection is best. If the lesion is on the patient’s right side, the innominate artery is cannulated and a RAO projection performed to identify the location of the right subclavian artery origin. Heparin is administered (75–100 U/kg). A  Glidewire® is placed in the aortic arch in exchange for the flush catheter. An angled catheter, usually 100 cm in length with a simple curve tip, such as a vertebral catheter, is placed over the Glidewire®. If the origin of the artery is relatively free of disease, the catheter is used to cannulate the subclavian artery and the Glidewire® is advanced. If there is a significant lesion at the origin of the subclavian artery, the catheter is used to direct the Glidewire® toward the artery orifice. The Glidewire® is used to probe the lesion with the intent of crossing it. If the lesion at the origin of the subclavian artery is very challenging to traverse with this relatively unstable platform, another approach is as follows. A  6-Fr or 7-Fr, 70-cm or 90-cm long, straight sheath with a radiopaque tip is passed and the tip advanced to within a few centimeters of the orifice of the subclavian artery. The dilator is removed and the appropriate selective cerebral catheter (see Chapter 9), 100–120 cm in length, is placed through the sheath. The tip of the selective catheter is placed beyond the end of the sheath. The steerable guidewire probes the orifice of the artery with support and direction provided by the selective catheter. The guidewire is advanced across the lesion and as far into the artery as possible to provide support for the catheter to be advanced (Figure 21.11). The catheter is advanced into the subclavian artery. Selective arteriography may be

performed if necessary. A stiffer guidewire, such as an Amplatz Super Stiff® or other exchange wire, is placed. The selective catheter is removed, the dilator placed, and the sheath advanced into the artery origin. Arteriography and heparin flush administration is performed through the side arm of the sheath. The best lesions for angioplasty and stenting in this area are short and located well proximal or distal to the vertebral artery. A lesion juxtaposed to the vertebral artery might be better treated with open surgery. The endovascular option usually involves stent placement in the vertebral and subclavian arteries. The balloon diameter is usually between 6 and 8 mm. The balloon catheter is placed across the lesion. The balloon is inflated and resolution of the atherosclerotic waist is observed using fluoroscopy. Often the location of the origin of the subclavian artery can be visualized during balloon inflation. Because the subclavian artery is soft and a rupture in this location has potentially disastrous consequences, it is important to avoid overdilation. Subclavian artery orifice lesions are usually treated with balloon-expandable stents since these lesions are often heavily calcified and spillover lesions from the aortic arch and the artery are relatively fixed in position at this site. Lesions in more distal locations are best treated with selfexpanding stents, since the artery is more flexible and mobile in these areas and may be affected by external structures and forces. Stents should be avoided near the crossing of the first rib and distal to the humeral head since these are areas of very high flexibility and with potential for external impingement. Stent placement considerations in the subclavian artery are similar to those for the common carotid artery. After angioplasty, if the sheath is in a stable position for stent placement, it is left in position. If the position is a bit unstable, the tip of the sheath can be advanced a centimeter, or a few centimeters, over the actively deflating balloon in order to get the sheath into a slightly more stable position prior to stent placement. A premounted stent on the appropriately sized balloon with a 90–120-cm shaft length is used for orifice lesions (Figure 21.11). The balloon-expandable stent size for the proximal common carotid artery is usually 6–8 mm. The balloon and stent are passed through the sheath and across the lesion and the stent is deployed. Advancing the sheath across the lesion

The subclavian and axillary arteries  295

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Fig. 21.11  Balloon angioplasty and stenting of the subclavian artery through a transfemoral approach. (A) A guidewire is placed in the subclavian artery and across the lesion. (B) A long sheath is placed with its tip in or near the origin of the subclavian artery. An angioplasty catheter is placed. (C) Balloon angioplasty of the subclavian artery lesion is performed. (D) The stent is delivered to the site of the lesion. (E) Stent deployment is performed. Caution is exercised during stent deployment to avoid engaging the tip of the sheath with the stent and deployment in proximity to the origin of the vertebral artery. (F) Completion arteriography is performed through the sheath.

for stent delivery is usually not necessary as long as the sheath tip has a secure purchase on the artery origin and the lesion has been predilated enough to permit passage of the catheter. Self-expanding stents are more likely to be used in the subclavian artery, when the lesion is distal to the origin, and also in the axillary artery. The self-expanding stent diameter should be 8 or 10 mm and the delivery catheters are 120 cm in length. The delivery catheter is passed through the sheath and across the lesion, and the stent is deployed. Poststent balloon angioplasty is performed. Completion arteriography is performed through the sheath. Lesions at the orifice of the subclavian artery pose similar challenges to those that occur at the common carotid artery origin. When the sheath is withdrawn to expose the stent, the tip of the sheath loses its purchase on the artery. When treating this type of lesion from a transfemoral approach, pull the sheath back slowly and place its tip in the arch

but close to the origin of the artery. Another option is to place the stent through a retrograde, transbrachial approach. If the lesion extends to the vertebral artery, care must be taken when deploying stents at this location as the origin of the vertebral artery is at risk for injury. This is also a location in the subclavian artery where there is some significant curvature. A  self-expanding stent may potentially be useful when the lesion is distal to the origin and in a tortuous segment of the artery. Avoid choosing a stent that is too long; a calibrated catheter is ­useful for this. To obtain the best view of the origin of the vertebral artery, sometimes it proceeds directly ­ from the superior aspect of the subclavian artery but sometimes also it comes off the posterior aspect of the subclavian artery. A slight craniocaudal angulation (5–10 degrees) may help visualize the vertebral artery origin. After placement of a self-expanding stent, the balloon may be gradually upsized so that

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the artery is gently dilated and the risk of rupture is diminished. If the brachial approach is chosen, the catheter is advanced from the brachial side of the lesion and there is only really one place for this guidewire and catheter system to go, and that is retrograde directly into the lesion.

Retrograde approach to the subclavian and axillary arteries The transbrachial or transradial, retrograde approach to the subclavian and axillary arteries is direct and does not require selective catheterization from as remote an entry site as does the transfemoral approach (Figure 21.12). The patient’s ipsilateral arm is extended at the side. A working table is placed at the end of the arm board to accommodate the guidewires and catheters. The transbrachial approach may be performed through either an open exposure of the artery or a percutaneous puncture. The guidewire is advanced retrograde using fluoroscopy. A 6-Fr sheath is usually required, either 30 cm or 45 cm in length. It is sometimes useful to place a longer sheath, depending on the location of the lesion, and to perform retrograde arteriography through the side arm of the sheath. Heparin is administered. The guidewire is advanced through the lesion. When the lesion of interest is at or near the origin of the subclavian artery, it is usually

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best to place a pigtail catheter through the femoral artery and perform arch aortography using a pressure injector. Retrograde arteriography through a short sheath is usually not possible. After the guidewire is advanced across the lesion, a straight catheter with multiple side holes may be advanced over the wire until its tip is proximal to the lesion, and this catheter may be used for arteriography. If the lesion is proximal to the vertebral artery, the guidewire must be advanced into the descending aorta to maintain adequate control at the intervention site. The guidewire is directed into the descending thoracic aorta using a selective catheter with a bend at the tip. A balloon catheter with a 75-cm shaft is placed and the balloon inflated. Stenting of the orifice of the subclavian artery should be performed with a balloon-expandable stent. A premounted balloon-expandable stent is advanced to the origin of the artery and deployed. Tortuous segments of the artery can be stented with self-expanding stents, as with the transfemoral approach. The shaft length for self-expanding or balloon-expandable stents through a brachial approach is 80 cm. Occasionally, when the lesion is juxtaposed to the vertebral artery and an endovascular option is better than a carotid–subclavian bypass, a subclavian artery stent can be placed through a femoral artery access and a wire and/or distal filter placed in the vertebral artery using a brachial approach.

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Fig. 21.12  Balloon angioplasty and stenting of the subclavian artery through a transbrachial approach. (A) A guidewire and sheath are placed through a brachial artery puncture or cutdown. (B) A balloon catheter is advanced through the sheath and into the lesion and balloon angioplasty is performed. (C) The balloon is withdrawn. (D) Stent placement is performed. (E) Completion arteriography is performed using a retrograde approach through the sheath.

22 Visceral and renal artery interventions APPROACH TO THE VISCERAL ARTERIES The operator must decide whether to approach the visceral arteries through a femoral access or an upper extremity access. The advantages of the femoral access are that it is commonly performed, clinicians are comfortable with the procedure, and closure devices may be used. The development of options for an articulated sheath has made access from an inferior direction simpler for treatment of downsloping vessels such as the superior mesenteric artery (SMA). When the downsloping angle is severe, it may make more sense to come from a radial artery or brachial artery access. The distance is slightly longer, but passage of a crossing wire and placement of a stent become simpler when the direction of the platform is consistent with the overall direction of the visceral vessel being treated. In some patients, the anatomy along the access route can be hostile. If the infra­ renal aorta or the supraceliac aorta is severely diseased, this may affect the decision about which way to approach the visceral vessels. Preoperative CTA can be used to help make this decision. The trajectory of each of the vessels on these imaging studies can be assessed. A 6.5-Fr articulating sheath, which allows the sheath tip to be manipulated into various degrees of curvature, is available. This is quite helpful in supporting visceral and renal artery treatment since these vessels come off the aorta at an angle.

CELIAC AND SUPERIOR MESENTERIC ARTERY ANGIOPLASTY AND STENTING Visceral artery stenoses or occlusions may be visualized by CTA. Many are asymptomatic, but when accompanied by abdominal pain or other signs of

visceral ischemia, they may require urgent treatment. A visceral artery lesion identified on angiography often appears longer than it actually is. An occlusion or stenosis usually starts at the origin of the artery and the precise location of the origin can sometimes be difficult to identify during the procedure. Frequently, there are hints as to where the origin of the artery is located or if there is a beak of contrast or a significant amount of calcification in the area where the artery is located. During cannulation of the visceral arteries, imaging is best conducted with the C-arm in a straight lateral position. The position of the arms is problematic since in the straight lateral imaging position, the upper extremities interfere with the fluoroscopic image. Sometimes, a steep oblique is adequate to visualize the origins of the visceral arteries. If a lateral position of the image intensifier is required, the arms can be stretched above the patient’s head or they can rest over the anterior chest and abdomen. Balloon-expandable stents are generally used to treat these lesions since they usually occur at the origin of the artery. This procedure may be approached from either a transfemoral route or a transbrachial route, as described above (Figure 22.1). The angles for cannulating a flush occlusion of the SMA are fairly unfavorable from a transfemoral route. The celiac artery trajectory from the aorta may be perpendicular, or nearly so, and if this is the case, there is no particular advantage to one or the other approach to an occlusion. However, if the artery is patent but stenotic or if there is a beak of entry contrast into the artery, then it may be possible to cannulate it from either direction. It is usually a good idea to undertake a preprocedure study, such as CTA, which will indicate the location and severity of visceral artery occlusive disease. In addition, a full array of angle tip delivery sheaths or guide catheters 297

298  Visceral and renal artery interventions

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C

D

and premounted, balloon-expandable stents should be available, including low-profile systems. Systemic anticoagulation is administered. A  flush paravisceral aortogram is obtained. The location of the origin of the visceral vessel of interest is identified. A sheath is placed, which is usually 6-Fr in diameter, and this sheath may have an angled tip, a curved or renal double curve (RDC) shape, or it may be straight. The length of the sheath must be adequate so that the tip of the sheath is near the origin of the vessel. If a challenging angle is present during a transfemoral approach, consider using a curved sheath or guiding catheter such as a RDC or inferior mesenteric artery (IMA) shape. From the brachial route, a straight or hockey stickshaped sheath tip is used. After sheath placement, the appropriately curved or angled 4-Fr or 5-Fr catheter is placed (Figure 22.2). The advantage of a more dramatically curved catheter is that it gives more angulation to the trajectory of the guidewire as attempts are made to cannulate an aortic side branch with an abrupt angle. The disadvantage of the more curved catheter is

Fig. 22.1  Considerations for proximal versus distal approach to the visceral arteries. (A) A lateral view of the celiac and superior mesenteric arteries is demonstrated. In patients with standard anatomy, the sheath approach can be either from a proximal or distal direction. (B) In situations where the visceral arteries have an acute angle of origin from the aorta, with a severely downsloping trajectory, a proximal approach may make the entire procedure simpler. (C) When the thoracic aorta or supraceliac aorta is severely diseased or aneurysmal, or has significant mural thrombus associated with it, it is usually safer to approach the visceral vessels from an inferior direction. (D) In situations where the infrarenal aorta is severely diseased and there is a large amount of pararenal atherosclerosis or mural thrombus, it is usually safer to approach the visceral vessels from a proximal direction through an upper extremity access.

that as the guidewire enters the lesion, the catheter may buckle in an unfavorable way and create instability in the system. A catheter that is well shaped to cannulate may be different from one that is well shaped to follow. If the origin of the artery is identifiable and open, the catheter is used to cannulate it. If there is a flush occlusion, the catheter and sheath are used to support the wire as it is used to probe for the opening through the lesion. Sometimes, a 0.014-inch guidewire with the lowest possible profile is required for this task. After the guidewire is in place, the catheter must be exchanged out, and in this setting the curvature in the catheter may attempt to drag the wire out of the artery. The artery may be cannulated using either a 0.014- or 0.035-inch steerable guidewire. Choose the catheter with the least amount of curve needed to make the gap from the tip of the sheath to the origin of the diseased artery. Often, it becomes apparent that it is helpful to withdraw the sheath a little bit to allow the catheter to take its full shape and have a full degree of mobility when attempting to cannulate the artery. If it transpires that this position is

Celiac and superior mesenteric artery angioplasty and stenting  299

A

B

Fig. 22.2  Catheterization of the celiac and superior mesenteric arteries. (A) A hook-shaped catheter is selected. The image intensifier is placed in the lateral or near lateral position. The catheter tip is used to engage the orifice of the artery. A 0.035-inch Glidewire® or a low-­profile guidewire (0.018 or 0.014 inch) is advanced. The celiac artery is usually short and the guidewire tip usually finds an early branch of the artery and follows a curving path. Guidewire placement in the SMA usually follows a straighter, diagonal and downward course. (B) After the catheter tip is engaged and the wire advanced, the catheter shaft is withdrawn slightly and the tip usually engages and slides into the visceral artery.

not supportive enough, usually the sheath can be advanced directly over the catheter with the guidewire in it and protruding. The “no touch” technique is frequently employed when an artery origin lesion is present. When the lesion is slightly farther from the origin of the artery so that there is a stump of relatively nondiseased vessel, cannulation is usually a simpler procedure. The opening of the artery is cannulated with the catheter first and then the wire is placed through that location. Once the wire is in the lesion, care must be taken as the lesion is being crossed not to catch the wire on any undesirable locations or create a subintimal channel. Keep in mind that the shape of the catheter will change as a longer distance of guidewire and a stiffer portion of the wire is passed through the lesion and also through the catheter head. Once the guidewire is across the lesion, the same catheter can usually be used to exchange for a more favorable guidewire with which to perform the stent placement. As in the case of other aortic branch lesions, the celiac artery and SMA can be treated using either a 0.035

system or a lower-profile system (i.e.,  0.014- or 0.018-inch diameter system). The advantage of the 0.014-inch diameter system is that the sheath required is not quite as large and despite using a 6-Fr sheath or even a 5-Fr sheath, you can consistently obtain interim angiographic images by injecting contrast through the side arm of the sheath and around the treatment catheters. The other advantage of the small caliber system is that low-profile balloons and stents are more likely to make any sharp turns in the access sheath and pass across the lesion since they are so much lower profile. The 0.035 systems frequently require predilation in order to pass the stent into the lesion. The advantage of the 0.035 system is that it can be used with a larger and very stiff guidewire, which can make the whole system, including the guiding sheath or guiding catheter, quite a bit more stable. The wire length accommodated by the celiac artery is usually shorter than the SMA. The celiac artery and its branches are shorter and a lot more tortuous. After feeding a certain length of guidewire into a tortuous artery, there is usually a build-up of tension and eventually push back against the wire. In the SMA, there is usually a relatively lengthy segment distal to the lesion. This makes the system more stable. However, the usually fairly severe angle of origin from the aorta increases the tension and makes the system comparatively a little less stable. Once the guidewire is across the lesion, care must be taken to ensure that it is actually in the correct location. Even if it is in the correct artery, care must be taken to ensure that it has not gone into some small branch or collateral branch out of the main artery just distal to the lesion. With regard to the SMA, a left anterior oblique (LAO) projection is often best to follow the guidewire since the artery tends to extend anteriorly and toward the right at its root. With regard to the celiac artery, a straight lateral or steep oblique is usually best to follow the wire, but a substantial amount of image quality is lost in doing this since you are shooting X-rays through the wider part of the person from one side laterally to the other. The wire going into the SMA can extend for many centimeters distal to the lesion and into the distal SMA, and this can provide a fairly good rail over which to work (Figure 22.3). An alternative method of access is demonstrated in Figure 22.4. Steerable guide sheaths are available that significantly improve the ability to place a sheath into an inferiorly slanting visceral

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Fig. 22.3  Stenting of a superior mesenteric artery lesion. (A) The guiding sheath or catheter is advanced so that its tip is in proximity to the SMA. A hook-shaped angiographic catheter is placed. (B) A 0.014-inch guidewire is advanced. The angiographic catheter is used to support and direct the guidewire. (C) The catheter is removed. The guidewire is advanced into a stable p ­ osition. (D) A ­premounted, low-profile, balloon-expandable stent is advanced directly into the lesion. (E) The stent is placed at the orifice of the artery.

Fig. 22.4  Use of a steerable guide sheath to access the superior mesenteric artery. Shown is a 6.5-Fr sheath that offers the operator the opportunity to control the shape of the sheath in one direction, providing angulation on the basis of a control knob.

Celiac and superior mesenteric artery angioplasty and stenting  301

vessel using a femoral approach. The steerable guide sheath may also be used in the same manner when approaching the renal arteries. The celiac artery has some technical differences that distinguish it from the SMA. The artery begins to make turns immediately after its origin. It is not at all uncommon to place the guidewire within the celiac artery and for it to be only within the artery for a few centimeters before it encounters resistance due to the tortuosity of the branches of the artery. The celiac artery is usually quite short and this requires great accuracy in placing stents. The celiac artery also usually has an early branch point with an abrupt change in caliber and is more likely than the SMA to exhibit poststenotic dilation. There is usually no available length of celiac artery in which the access sheath can be seeded. Try to choose the best celiac artery branch to provide stability. Once the guidewire is in place, the right length and diameter of stent must be selected and placed in the right spot so that the trailing end of the stent is flush with the aorta or protruding slightly into the aorta so that the entire lesion may be treated. Because the celiac artery is often so short, the lesion may be the whole length of the celiac artery, with branches immediately distal to that. Usual stent lengths in the celiac artery are 12–18 mm, rarely longer. The usual stent diameter is 6–8 mm. After stent placement, follow up with poststent angioplasty. If the artery is very short and the distal end of the lesion is very close to the branches, it is occasionally necessary to place a couple of guidewires into different celiac artery branches. SMA treatment likewise has its nuances. Passage of the stent through the bend from the aorta into the SMA is sometimes difficult. The combination of the angle and a tight lesion make it more likely than the celiac artery to require predilation prior to stent placement. Poststenotic dilation is less likely but can definitely happen and the stent should not be matched to this diameter. SMA stents are typically balloon-expandable and are usually a little longer; up to 3 cm is not unusual. The common diameters range from 6 mm to 8 mm. There are challenges in stent placement in the visceral segment. Fluoroscopic image clarity is diminished because of the depth of the location and the thickness of the tissue that must be penetrated. There is a continuous movement of vascular structures. Bowel gas often obscures the target site. This is an area where heavy calcifications may

occur, especially along the anterior wall at the origins of the visceral arteries and sometimes along the posterior wall, where it is desirable to avoid embolization by disrupting this material. If there is a severe angle of exit from the aorta, and especially if it is a SMA or there is significant infrarenal pathology, then a transbrachial approach is more desirable. It is usually best to place the tip of the delivery sheath either inside the origin of the artery or very close to it to support treatment. Covered stents may also be used for treatment of the celiac artery and SMA. There are some data to suggest that the patency of covered stents is better than that of bare metal stents. There are some lowprofile balloon-expandable covered stents that can be used, ranging from 5 cm to 7 cm. The expected foreshortening is a little less than with bare metal stents. One potential advantage of covered stents is that they remove one mechanism of intimal hyperplastic recurrent stenosis through the open spaces between the struts of the stent. There are two potential disadvantages. One is that the graft material takes up some of the lumen. The other is that some arteries have early branches. This is especially true of the celiac artery, and in these situations, coverage of branch arteries is not desirable. If performing a transbrachial approach, place a 4-Fr access sheath in the left brachial artery using a micropuncture needle and a 4-Fr sheath. After placement of a 4-Fr sheath, administer systemic anticoagulation. A 90-cm Omni® Flush catheter is passed along with a Glidewire®. In the arch of the aorta, the Omni® Flush catheter is turned posteriorly and used to direct the guidewire into the descending aorta. The image intensifier is placed in the LAO position for this maneuver. The flush catheter is advanced and a visceral aortogram obtained. The approximate distance to the lesion is estimated against the length of the catheter. A stiff guidewire is passed through the catheter and the catheter is removed. The 4-Fr sheath is removed from the arm, dilators are used, and then a long 6-Fr sheath is placed so that the tip of the sheath is in the aorta near the target lesion. Once the 6-Fr sheath is placed in the appropriate location, oblique projections of the SMA and celiac artery can be obtained and an angle tip, long catheter, such as a 125-cm length 5-Fr vertebral catheter, is placed. After placement of the catheter, it becomes apparent where the tip of the sheath needs to be and the sheath is withdrawn slightly as needed. It is not possible at this point to advance the sheath on its own without

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the dilator and the stiff guidewire and, therefore, it is inserted beyond the point that is required and then slightly withdrawn when the time comes. By pointing the angle tip catheter toward the origin of either the celiac artery or the SMA, whichever requires treatment, the guidewire may then be advanced from the tip of the catheter. The shape of the aorta often causes a rotational bias in the sheath. When this happens it may point toward the lesion intended for treatment or it may point away. The same steps are followed as described above when using the transfemoral route to accomplish stent placement, with the obvious difference of length requirements. The major difference in the transfemoral route is that access site management is a little simpler but the actual access to the visceral artery for stenting is often more complex due to angulation. This is because of the extreme angles of origin of some visceral arteries. After the sheath is placed and the lesion is crossed, the sheath and the guidewire may try to pop out during the procedure.

RENAL ANGIOPLASTY AND STENTING The technique of renal angioplasty and stenting has been greatly simplified by the introduction of the 0.014-inch diameter systems in renal

revascularization. The renal arteries are usually approached retrograde using a femoral access, but an antegrade approach through a brachial puncture site or radial access may occasionally be used when the angle of the renal artery takeoff from the aorta is narrow or when severe aortoiliac disease prohibits catheterization of this segment. Renal revascularization may also be performed using an IMA-shaped guiding catheter, with the use of a manifold device and also the possibility of a distal protection device. A detailed discussion of renal artery catheterization can be found in Chapter 9. Information about aortorenal and selective renal arteriography can be found in Chapter 11. Supplies required for renal artery intervention are listed in Table 22.1. In deciding whether to treat a renal artery from the transfemoral route or the transbrachial route, there are a few considerations. Most of the time it is fairly straightforward to treat a renal artery stenosis from a transfemoral route. The distance is shorter, the imaging is simpler, and the procedure is overall safe and reliable. One disadvantage of the transfemoral route is that there may be some associated infrarenal aortic pathology, such as an abdominal aortic aneurysm, mural thrombus or atherosclerosis, or other lesion, which may substantially influence the safety of the case. If there is significant iliac tortuosity, this will bias the catheter

Table 22.1  Supplies for renal artery intervention

Guidewire

Starting guidewire Selective guidewire

Catheter

Exchange guidewire Flush catheter Selective catheter

Sheath

Selective guide sheath

Balloon

Balloon angioplasty catheter

Stent

Balloon-expandable stent (premounted – 0.014 inch)

Bentson Magic torque Grand Slam Rosen Omni® Flush Cobra C1, C2 Renal double curve Renal curve 1, 2 SOS Omni® 2 Destination® angled Renal double curve Balloon diameter Balloon length Catheter shaft Stent diameter Stent length Shaft length

Length

Diameter

145 cm 180 cm 180 cm 180 cm 65 cm 65, 80 cm 65, 80 cm 65, 80 cm 80 cm 45 cm 55 cm

0.035 inch 0.035 inch (marker tip) 0.035 inch (angled tip) 0.014 inch (soft tip) 5-Fr 5-Fr 5-Fr 5-Fr 5-Fr 6-Fr, 7-Fr 5-Fr 4, 5, 6, 7 mm

2, 4 cm 75 cm 5, 6, 7 mm 12–29 mm 80 cm

Renal angioplasty and stenting  303

or sheath toward one side or the other and create extra challenge. This may work to your favor if this is the side you are treating; however, it may work aggressively against you and serve to turn the catheter and/or sheath to the opposite side to which you desire throughout the procedure. Another situation in which it is helpful to abandon the transfemoral route and go with the transbrachial or transradial route is when there is a severe and acute angle of takeoff of the renal artery so that it is significantly downsloping, similar to a SMA. Although this is usually possible to do through a transfemoral route, having a critical or even preocclusive lesion near the origin of the renal artery is sometimes extremely difficult to cannulate when coming from the transfemoral route. The combination of a critical lesion that must be crossed and a severe angulation at nearly the same location can make access and stability of the platform challenging. After the guidewire is across the lesion, the more angulated the approach, due to the curvature imposed by the turn from the aorta into the renal artery, the less stable the system and the less pushability and trackability the operator has. Usually, a low-profile system using an 0.014- or 0.018-inch platform works best. A low-profile system also facilitates the possibility of using a rapid exchange system and primary stenting with fewer exchanges. After retrograde femoral puncture, the guidewire is passed to the level above the upper abdominal aorta.

A 4-Fr or 5-Fr flush catheter is placed and the guidewire removed. The catheter head is placed at the junction of the first and second lumbar vertebral bodies. It is best to perform a complete aortoiliac arteriography if renal function permits. This allows accessory renal arteries and other variations to be identified, as well as disease that is present along the approach to the renal arteries. The operator then knows where other disease is located that may potentially cause complications during intervention. After this is performed, a magnified view of the aorta and renal artery origins should be obtained. The image intensifier usually has an oblique orientation slightly toward the side of probable intervention. After the image intensifier is optimally located, it is usually best to leave it in that position until after the artery is cannulated. The renal arteries are unique in terms of their mobility with breathing. The origins of the renal arteries are relatively fixed in place by  the diaphragmatic crus. The renal parenchyma and surrounding tissues within Gerota’s fascia are mobile with diaphragmatic excursion. The result of this anatomic arrangement is that the angle of takeoff of the renal arteries from  the aorta varies with the ventilatory cycle. The anatomic picture portrayed varies depending on how the diaphragm was held during the arteriography. A fully held breath tends to accentuate the acute angle at the origin of the renal artery by pushing the kidney caudad (Figure  22.5). Because  the

L1

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L2

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B

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A

Fig. 22.5  Renal artery position is dependent on diaphragmatic motion. (A) At full exhalation, the kidney position is high in the retroperitoneum and the angle at the renal artery origin is affected accordingly. (B) During mid-inhalation, the angle of takeoff at the renal artery origin becomes more acute. (C) At full inspiration, the renal artery origin is at an even more acute angle.

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kidneys move up and down continuously with the breathing cycle, it is frequently helpful to have the patient hold their breath prior to angiography but also prior to stent placement itself so that accuracy of stent placement can be achieved. Frequently, a deep breath causes too much displacement and will help to force the kidneys inferiorly and accentuate the angle of origin of the renal arteries. Often it is helpful to have the patient exhale and hold their breath while in exhalation so that the kidneys are elevated, and this tends to deaccentuate the angle of takeoff of the renal artery. The renal arteries tend to egress from the aorta in a posterolateral direction so it is frequently valuable to use an ipsilateral anterior oblique of from 5 to 15 degrees in order to see the renal artery origin. If the preoperative study obtained is either a CAT scan or MRA, this can be used to assess the best angle for visualizing the renal artery origin. Even though many arteries will be seen in their best projection by a slight anterior oblique, some arteries do not follow that rule. If the aorta is a little

A

C

rotated, as often occurs in the setting of infrarenal aortic aneurysm, one artery may even originate a little bit anteriorly. Systemic heparin is administered. A 6-Fr sheath or 8-Fr guide catheter is advanced over the guidewire (Figure 22.6). A guiding sheath or catheter is selected that best fits the angle and curvature of the renal artery origin. There are numerous shapes, specially designed for renal artery intervention, which are available through different companies (Figure 22.7). The tip of the sheath is soft and radiopaque. The transition from dilator to sheath is smooth, and the distance that the dilator extends beyond the sheath is very short. This permits the tip of the sheath to be placed within the renal artery without a long segment of leading dilator tip advancing into the distal renal artery. A guiding sheath with a 6-Fr or 7-Fr shaft and a 45-cm length is adequate. If a guide catheter is selected, it may have an IMA shape, a RDC shape, or some other curve. The tip is curved but somewhat flexible. A  guidewire is advanced through the guide

B

D

Fig. 22.6  Balloon angioplasty of the renal artery. (A) The left renal artery is cannulated with a Cobra catheter and the guidewire is advanced across the stenosis. (B) An angioplasty balloon is advanced over the guidewire and across the lesion. In this case, the lesion is in the mid-renal artery, as might be seen with fibromuscular dysplasia or, occasionally, with atherosclerosis. (C) Balloon angioplasty of the left renal artery is performed. (D) A completion renal arteriogram is obtained by injecting contrast through the guiding catheter or guiding sheath. In this case, with a mid-renal artery lesion, if the result of angioplasty is acceptable, no stent is required.

Renal angioplasty and stenting  305

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B

C Fig. 22.7  Access for renal artery intervention. Renal guiding sheath tips are shown here. These sheaths have a hemostatic valve, a side arm, and a dilator and are used for progressively more acutely angled renal arteries.

catheter. When the tip of the catheter falls into the orifice of the renal artery, the guidewire is advanced (Figure  22.8). If this is an unfavorable angle, another option is to place a C2 Cobra catheter or other appropriate curved tip catheter and use one of these catheters to cannulate the renal artery. The renal artery is cannulated, the 0.014-inch guidewire advanced across the lesion and into the distal renal artery, and the guide catheter tip placed close to the lesion. The guidewire choice should be one that has a relatively stiff body across the location of the lesion and also a floppy wire tip so that injury to the renal parenchyma can be avoided. Care must be taken to avoid inadvertently advancing the wire into the parenchyma and causing a kidney injury. Another option for access to the renal arteries is the steerable sheath (Figure 22.4). This is especially useful if the angle of origin of the renal artery is acute and necessitates a more angulated turn to achieve access. A critical orifice lesion may make it difficult to enter the renal artery. This is the case with the vast majority of atherosclerotic renal artery lesions. In this case, the steerable guidewire tip must be used to gently probe the origin of the artery. After the guidewire traverses the lesion, it is advanced into a secondary branch. This is done to maintain as much purchase on the artery as possible. However, the guidewire should not be forced or advanced against resistance because it can perforate the parenchyma. Another option is to use the “no touch” technique. The sheath is advanced into the aorta in the proximity of the

renal artery (Figure  22.9). A stabilizing guidewire is placed, which protrudes into the aorta and lays against the wall of the aorta to hold the tip of the sheath in a steady position. Through the tip of the sheath, the renal artery lesion is probed with a directional guidewire and crossed with the least amount of trauma. A selective catheter is passed over the guidewire into the renal artery if selective arteriography or pressure measurements are required or if a different guidewire is desired over which to perform stenting. Nitroglycerine may be administered through the catheter to help prevent renal artery spasm. Attempting to assess the hemodynamic significance of the renal lesion by measuring pressure across it can be challenging. It is not well understood if a pressure drop across the lesion is significant and how much of a drop there has to be to represent a physiologically significant change. In addition, when measuring the pressure using a 4-Fr or 5-Fr catheter, there may be some decrease in pressure because of occupation of the residual lumen of the renal artery by the pressure measuring device. In order to accurately measure pressure, it means potentially crossing the lesion more than once by placing the pressure measuring catheter across the lesion and then withdrawing it. As the kidney loses its ability to vasodilate distal to the stenosis, it may become more resistive. This will tend to equalize the pressures proximal and distal to the lesion and this may explain why sometimes an apparently significant appearing lesion has a less than significant pressure drop across it. Likewise, with vasodilating agents, if the kidney is physically unable to vasodilate any further than it already is, this will lead to a less dramatic hemodynamic response than one would anticipate based on the severity of the lesion. Another option for pressure measurement is to use a pressure wire, since the wire itself takes up less space and obstructs the lumen less than a 4-Fr or 5-Fr catheter. After these maneuvers, a guidewire is inserted into the catheter and across the lesion for treatment. Keeping the guidewire in the correct place is a challenge throughout the remainder of the procedure. Every maneuver tends to move the guidewire and tension builds up around the sharp turn from the aorta into the renal artery. The end organ is so close that only a short length of relatively soft

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G

Fig. 22.8  Balloon angioplasty and stent placement through a guiding sheath. (A) A guidewire and guiding sheath are placed in the aorta. (B) The dilator is removed. (C) A selective catheter, such as a C2 Cobra, is placed through the sheath and into the renal artery. Guidewire access across the lesion is obtained. (D) The balloon catheter is advanced through the guiding sheath and over the guidewire. The tip of the guiding sheath is maintained in proximity to the renal artery origin. It is often helpful to advance the sheath a little bit to support the passage of the balloon and stent catheter and keep the platform stable. (E) A premounted, balloon-expandable stent is placed at the location of the lesion. (F) The stent is placed with balloon inflation. In general, because it is usually aortic plaque that is “spilling over” into the renal artery, it is desirable to place the stent so that its leading end protrudes into the aorta by 1–2 mm. (G) Poststent angiography is performed through the sheath while maintaining guidewire access.

(atraumatic) guidewire can be maintained within the artery. The guiding sheath or catheter may be advanced close to but not into the lesion over the selective catheter and guidewire. Prior to stent placement,

predilation may be performed using a 2–4 mm balloon to create a tract for stent delivery. The angioplasty balloon is usually 2 cm in length and has low-profile features with a monorail system. After balloon angioplasty, the guiding sheath or

Renal angioplasty and stenting  307

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B

C

Fig. 22.9  No touch technique. (A) The guiding sheath or guiding catheter is stabilized by passage of a guidewire that leans on the side wall of the aorta. (B) The tip of the sheath is stable and avoids direct encounter with juxtarenal aortic disease. A 0.014-inch guidewire is passed through the same access and into the renal artery. (C) The premounted stent delivery catheter is advanced into position.

guiding catheter may be gently advanced using the angioplasty catheter for support, especially if the sheath had to be withdrawn a little bit in order for the balloon to be inflated. The balloon catheter is removed. After the stent is placed on the wire, it is advanced into position. It is quite commonly a challenge getting the stent across the lesion and forceful advancement when the stent is not going easily may force the guidewire and/or guide catheter to back up in an undesirable way. This is where system stability is important to permit the operator to push when needed and obtain acceptable results. Contrast is puffed from the sheath to reassess the landmarks for correct placement. Because the premounted stent and its catheter may fill the lesion, there may not be any filling of contrast into the artery past the stent until the stent is deployed. However, the contrast should puff around the origin of the artery and give an identification of the location of the stent at the origin of the renal artery. When the stent is appropriately positioned, it is rapidly deployed and, after deployment, the balloon is deflated. This is usually best done with the patient holding their breath in a manner similar to that which allowed the best image on angiography. The same balloon is used to expand and flare both the proximal and distal ends of the stent. Occasionally, a slightly larger balloon is used to flare the proximal end of the stent in the aorta. In doing this, it is best to apply a little bit of forward pressure on the sheath to support the balloon in the trajectory that works best for the stent (Figure 22.10). The stents used for the renal arteries range in length from 12 mm to 30 mm and in diameter from 4 mm to 7 mm. The tendency by eye is to overestimate the length of the stent required.

These stent delivery catheters are 0.014-inch compatible, monorail system devices. The very low profile helps the stent to make the turn from the aorta into the renal artery and to cross a lesion that may have a very narrow residual lumen. The low-profile nature of these stents also permits administration of contrast around the stent delivery catheter while in the sheath and just prior to deployment. In general, the shortest length stent that will cover the lesion should be deployed. If the renal artery has substantial tortuosity, the stent will straighten a segment of the artery, leaving all the curvature over a shorter segment of remaining nonstented vessel. This can inadvertently create an undesired kink in the artery. Efforts should be made to avoid this situation. The monorail system also offers other advantages. A shorter wire is used, usually 180 cm. The operator controls the wire at the hub of the sheath instead of at the end of the wire, which is somewhere distant from the hub. Since the end organ is so close to the lesion, only a short distance is available distal to the renal artery stenosis and proximal to the renal parenchyma. In this setting, maximum wire control is desirable. A final diameter of 6 mm or more is desired. The balloon and mounted stent are advanced through the sheath and across the lesion. The guiding sheath is gently withdrawn to uncover the back end of the stent. The stent is placed so that the aortic end is deployed to treat the aortic plaque as it spills over into the renal artery, usually about 1 mm into the aortic flow stream. Aortic wall calcium deposits often provide a good landmark for this deployment. Inflation is observed using fluoroscopy and may cause flank pain. Completion arteriography is performed through the sheath.

308  Visceral and renal artery interventions

A

B

D

E

C

Fig. 22.10  Poststent placement balloon angioplasty. (A) The balloon-expandable renal artery stent is placed by expanding the balloon on which it is premounted. The sheath must be withdrawn enough to allow the balloon to expand. (B) When the balloon is deflated, it can be caught on the stent and there may be resistance when attempting to remove it. To allow this to occur more smoothly, the sheath tip is advanced along the wire so that the sheath itself can support the stent and prevent it from migrating. (C) The balloon is withdrawn slightly and positioned so that it can be used to flare the proximal end of the stent or at least perform a repeat angioplasty in the area where the disease is typically worst, which is at the origin of the artery. In this setting, after the balloon is positioned in the origin of the stent, the sheath must be withdrawn slightly to allow room for the balloon to expand. The tip of the sheath is used to support the balloon. (D) In patients with a severely downsloping renal artery, as in this situation, the wire is biased during stent placement and can significantly affect the position of the stent and the ability to perform poststent placement balloon angioplasty. In this example, with a downsloping left renal artery, there is significant curvature of the wire as it enters the renal artery. When the sheath is advanced all the way to the stent, the curvature can become worse. (E) When performing poststent placement balloon angioplasty in this setting, the balloon can be advanced so that it is positioned to dilate the proximal end of the stent. The sheath is advanced so that it can support the tilting of the balloon to accommodate the downsloping left renal artery and the left renal artery stent during balloon dilation.

After inflation of a balloon-expandable stent, the balloon occasionally becomes stuck. If this occurs, do not yank the catheter. Deflate the balloon fully, then advance the catheter a little to dislodge it from the deployed stent. If the balloon is difficult to withdraw from the stent, advance the tip of the sheath close to the end of the stent to support the stent during balloon removal so that its position is not loosened by catheter withdrawal. Smaller caliber guidewire systems have the advantages of crossing critical lesions with lowerprofile guidewires, permitting balloon angioplasty

with a very low-profile balloon, and allowing complex intervention through smaller caliber sheaths. The disadvantages are that they are not as radiopaque and provide less support than a 0.035-inch system. At some point, it may be appropriate to perform renal stenting with distal protection devices in order to limit distal embolization. There are disadvantages of the existing distal protection devices as applied to renal stenting. None of the currently available protection devices have a short enough landing zone to be adequate for most renal arteries.

Renal angioplasty and stenting  309

Most of the existing devices are based on guidewires that are not stiff enough to be stable in the setting of the acute turn from the aorta into the renal artery, as is required. Recurrent renal artery stenosis is difficult to assess on plain angiography. The best way to evaluate the degree of stenosis in this situation is with

IVUS. Treatment options for recurrent renal artery stenosis are standard balloon angioplasty, repeat stenting, cutting balloon angioplasty, drug-coated balloon angioplasty, or a combination of these. Covered stents may also be used if the caliber of the artery is adequate to accept the slightly higher profile of the covered stent.

23 The infrarenal aorta, aortic bifurcation, and iliac arteries: Advice about balloon angioplasty and stent placement INTRODUCTION Stents have had a profound impact on the management of atherosclerotic occlusive disease of the aortoiliac segment and open surgery for aortoiliac occlusive disease has decreased significantly over the past 10 years. The long-term results of endovascular intervention are not quite as good as with open surgery, but they are reasonable and continue to improve. At the same time, morbidity and mortality appears to be much less with endovascular procedures than with open procedures of the aortoiliac segment. Endovascular approaches are being deployed for many patients with TASC D lesions. The long-term success of aortoiliac intervention is closer to the results of open surgery than with any other endovascular intervention. In addition, the short-term risk of percutaneous intervention is so much less than with open surgery that endovascular approaches have become the treatment of choice for most patients. Open surgery is reserved only for patients who have failed endovascular intervention or in whom a percutaneous approach is not technically feasible. Chapter 9 provides a step-by-step approach for crossing the aortic bifurcation. Chapter 11 provides information about aortoiliac arteriography. Supplies for aortoiliac intervention are listed in Table 23.1. Aortoiliac occlusive disease is usually treated with coaxial catheters on a 0.035-inch platform. Most aortoiliac lesions can be treated using 6-Fr or 7-Fr sheath access. Covered stents may require an 8-Fr access.

Stent–graft components, such as those needed to treat aneurysmal disease, require sheaths in the range of 12-Fr to 16-Fr.

AORTA Lesions of the aorta that are indicated for treatment are usually treated with a stent. Isolated, focal stenoses of the infrarenal abdominal aorta often respond to balloon angioplasty alone, and this approach has reasonable long-term success, but stent placement has even better results over the long run (Figure 23.1). The availability of stents has also permitted the treatment of more complex lesions with endovascular intervention. If the aorta is suspected as a source of emboli, a covered stent or stent–graft should be considered. Stents provide an opportunity to approach lesions that would not be expected to respond to balloon angioplasty alone. Aortic lesions that extend to the bifurcation also require kissing stents placed through each iliac artery. Ideas, concepts, and tools are currently being developed for complete reconstruction of the aortoiliac segment with stents or covered stents or a combination of these. Lesions that are limited to the infrarenal aorta may be accessed through a unilateral femoral approach on either side. Lesions of the aorta that extend near or into the aortic bifurcation should be accessed with a guidewire placed through each iliac artery. This is discussed in more detail in the next section. If there is coincidental, nonbifurcation,

311

312  The infrarenal aorta, aortic bifurcation, and iliac arteries

Table 23.1  Supplies for aortoiliac intervention

Guidewire

Catheter

Sheath

Balloon

Stent

a

Starting guidewire Selective guidewire Exchange guidewire Flush catheter Selective catheter Exchange catheter Access sheath Straight sheath Selective sheath Balloon angioplasty catheters

Balloon-expandable

Self-expanding

Bentson Glidewire® Amplatz Super Stiff® Omni® Flush Angled glide catheter Straight Standard hemostatic access Long straight with radiopaque tip Over bifurcation Balloon diameter Balloon length Catheter shaft Stent diameter Stent length Delivery on 75-cm-length angioplasty balloon catheter Nitinol stent diameter Stent length Delivery catheter length

a

b

Length

Diameter

145 cm 150 cm 180 cm 65 cm 65 cm 70 cm 12, 13 cm 30, 35 cm 45, 55 cm

0.035 inch 0.035 inch 0.035 inch 4-Fr 5-Fr 5-Fr 6-Fr, 7-Fr, 9-Fr 7-Fr, 9-Frb 6-Fr, 7-Fr 6, 7, 8, 10, 12, 14, 16, 18 mm

4–10 cm 75 cm

5-Fr 6–22 mm

25–50 mm

8–14 mm (covers most) 40, 60, 80, 100 mm 80 cm

A 9-Fr or 10-Fr sheath is used to introduce large diameter balloons for aortic angioplasty (>12-mm diameter) or a Wallstent® larger than 14 mm. A 9-Fr sheath is used to introduce a large Palmaz™ stent (P308) for diameters of 10–12 mm.

unilateral iliac disease that also requires treatment along with a separate aortic lesion, the access should be ipsilateral to the iliac lesion. This permits treatment of both the aortic and iliac lesions through the same approach without passing guidewires and sheaths over the aortic bifurcation. Retrograde passage of the guidewire is performed from the femoral puncture site and an aortogram is acquired using a flush catheter. After appropriate arteriography is completed and the decision made to proceed with treatment, 50–75 U/kg of heparin is administered. The operator may consider a larger bolus of heparin when treating very complex or embolizing lesions or preocclusive stenoses, or if longer indwelling catheter times are anticipated. The catheter is removed and an appropriately sized sheath placed through the femoral entry site (Figure 23.2). If there is significant tortuosity, the lesion is very complex, or a large sheath is anticipated, the operator should consider placing an Amplatz Super Stiff® exchange

guidewire to provide extra support during the intervention. Standard length hemostatic access sheaths of 10–13 cm may be used for simple balloon angioplasty and placement of stents. However, it is also useful to consider a 30- or 45-cm sheath with a radiopaque tip to treat aortic lesions. Interval arteriography may be performed through this type of sheath, with contrast administered in proximity to the target lesion site. The size of the sheath depends on the intended diameter to which the aorta is to be dilated and whether a stent will be placed. Balloon angioplasty may be performed up to 10-mm diameter using a 5-Fr catheter shaft through a 6-Fr sheath. Self-expanding nitinol stents up to 14 mm in diameter can also be placed through a 6-Fr sheath. Dilation to 12 or 14 mm is performed using a 5-Fr catheter shaft through a 7-Fr sheath. A 9-Fr sheath is required for 16–20-mm balloons. Balloon-expandable stents up to 9 or 10 mm in diameter may be placed through 7-Fr sheaths. A  9-Fr sheath is required for balloon-expandable

Aorta 313

A

C

B

D

E

Fig. 23.1  Endovascular approaches to aortic lesions. (A) A significant but focal lesion is isolated within the infrarenal abdominal aorta. (B) Balloon angioplasty of the aortic lesion is performed. (C) This more extensive lesion involves the infrarenal aorta and its bifurcation. (D) The lesion is approached by placing a guidewire retrograde through each femoral artery. (E) Balloon angioplasty is performed in the aorta and kissing balloons are used to dilate the bifurcation.

stents up to 12 or 14 mm. Larger diameters require 10-Fr or 12-Fr sheaths. Self-expanding stents larger than 14 mm require 9-Fr sheaths. Sheaths for covered stents vary from 6-Fr to 9-Fr in caliber. It is best to place the sheath or sheaths required for treatment as soon as the decision is made to proceed with treatment. Aortic angioplasty is performed with balloons ranging from 8 to 18 mm in diameter. Sizing the intended diameter of the aorta may be challenging because of the broad range of potential sizes, but there are several options. A flush catheter with 1-cm markers may be used for the aortogram, and the known distance between markers may be used

to calculate the desired diameter of the aorta for angioplasty. If IVUS is available, this probably provides the most accurate representation of vessel diameter. IVUS requires an 8-Fr sheath for a large diameter vessel probe. Another method is to proceed with balloon angioplasty using a balloon that is an underestimation of the probable aortic diameter and compare the inflated balloon profile with the preintervention aortogram. The selected balloon is advanced over the guidewire and into position using externally placed or bony markers. The balloon is inflated under fluoroscopy. The aorta may rupture at lower pressure than smaller diameter vessels, so inflation is performed

314  The infrarenal aorta, aortic bifurcation, and iliac arteries

A

B

D

C

E

Fig. 23.2  Balloon angioplasty of the aorta. (A) A guidewire is placed through a stenosis in the infrarenal aorta. (B) Aortic balloon angioplasty is performed. (C) A residual stenosis requires additional therapy. (D) Balloon-expandable stent placement requires the use of two overlapping stents to cover the entire lesion. (E) A single self-expanding stent placed in the infrarenal aorta is another option.

cautiously. Initial inflation with a slightly undersized balloon may be performed to evaluate how the lesion will respond to dilation. Less than 8 atm of pressure is usually required to dilate aortic lesions. Larger balloons tend to have longer shoulders that extend a centimeter or more beyond the location of the radiopaque marker. The shoulders of the balloon must be placed so that they do not extend into an area not intended for dilation, such as the proximal iliac artery. Balloon inventory for diameters larger than 10 mm is usually limited, so catheter availability should be confirmed prior to the procedure. If appropriately sized balloons are not available, two equally sized balloons of half the desired diameter are placed retrograde, one through each femoral artery, and inflated together.

The balloon is brought to full profile and then deflated. Repeat inflations may be performed if the waist has not resolved. The balloon catheter is withdrawn. Balloon deflation takes longer because the large balloon must empty through a relatively small lumen. Completion aortography is performed by exchanging the balloon catheter for an arteriographic catheter or by administering contrast retrograde through the sheath. Because the infrarenal aorta is a large vessel, clinical success is often achieved despite an angiographically suboptimal appearance. In practice, a lumen of 10–12 mm is usually sufficient to support bilateral iliac flow. A major risk of aortic angioplasty, especially with a large plaque burden, is lower extremity embolization. A lesion that

Aorta 315

A

C

B

D

Fig. 23.3  Management of an embolizing aortic lesion. (A) An ulcerated aortic lesion presents with embolization. (B) Percutaneous access is obtained through one femoral artery and open access is obtained through the other femoral artery. (C) An occlusion balloon is placed in the proximal right external iliac artery using percutaneous access to prevent distal embolization. A stent is placed through the open left femoral access. The left lower extremity outflow is clamped to prevent embolization. (D) Another option is to perform a percutaneous approach using a large sheath, such as a 14-Fr or 16-Fr sheath. Using this approach, a higher-profile covered graft, such as an aortic cuff, can be placed. The larger sheath usually prevents flow of embolic debris into the limb.

presents with embolization or appears to be prone to embolize can be treated with primary stent placement or stent–graft placement with outflow control (Figure 23.3). However, it is important to ensure that the lesion is not contained within a small aneurysm.

A large plaque burden also increases the likelihood of a residual stenosis. Pressure should be measured if it is not clear whether a bulky, residual plaque constitutes a hemodynamically significant lesion. If the lesion is significant, stent placement is a reasonable option. Many operators favor primary

316  The infrarenal aorta, aortic bifurcation, and iliac arteries

stent placement for aortic lesions, especially if there is a high degree of irregularity of the surface or a substantial amount of plaque. Primary stent placement permits the plaque to be caged by the stent and may decrease the likelihood of embolization or fragmentation during angioplasty. Choosing which stent to use can be a challenge. Self-expanding stents offer the advantage that the final resting diameter may be estimated to within 2–3 mm, as long as the selected stent is oversized and not too small in diameter. Self-expanding stents also permit a gradual enlargement of the lumen. After stent placement, progressively larger balloon diameters can be used for poststent placement dilation. If the patient complains of pain, the operator knows that the diameter is close to the desired size. The balloon-expandable stents have better hoop strength and the precision of placement is better. However, the diameter size must be accurate. Too small a stent diameter on placement will leave the stent in an unstable position and it may migrate before it can be fully expanded. Balloon-expandable stents must also be placed with a single inflation. If they are oversized, rupture is possible. When planning stent placement, a super-stiff guidewire may be used to take slack out of the system and improve placement accuracy. The appropriately sized sheath should be placed. A  long sheath (35 cm) with a radiopaque tip is useful. Supplemental arteriography may be performed through the sheath during stent deployment. Landmarks must be carefully considered and distances measured. Distance from the renal arteries and the aortic bifurcation should be considered. If the lesion extends to the aortic bifurcation, and this segment also requires treatment, it is probably best to place the aortic stent first, with single guidewire access in the aorta (Figure 23.4). A sheath is placed in the proximal common iliac artery on the contralateral side. After the aortic stent is placed, the contralateral guidewire is advanced very carefully through the aortic stent. When advancing the contralateral guidewire through the aortic stent, ensure that the wire does not go through the struts of the stent. This can be facilitated by using a floppy tip wire with a bend on the tip or by directing the wire with a supporting directional catheter. Kissing iliac stents can then be placed, advancing inside the distal end of the aortic stent if necessary. Placement of the stent too close to the renal arteries should be avoided. If the patient requires an

aortofemoral bypass at a later time, stents placed in the very proximal infrarenal aorta will necessitate suprarenal cross-clamp of the aorta. Self-expanding stents offer the advantage of a relatively larger stent diameter for a given sheath size. For example, a 7-Fr sheath accommodates 12–14-mm diameter self-expanding stents, whereas the largest balloon-expandable stent that can be placed through this sheath is 8–10 mm. Self-expanding stents should be oversized for the intended final diameter by about 2–3 mm. Nitinol stent length shortens by a few percent when expanded, but a Wallstent® length changes significantly with placement. The final resting length must be carefully estimated to ensure that the distal end of the Wallstent® does not extend beyond the aortic bifurcation. Any location along the length of the Wallstent® that does not reach its estimated final diameter causes the length of the stent to increase. When placing a self-expanding stent across a ledge-like lesion, it is best to attempt to gain lumen diameter with aggressive prestent angioplasty of this type of focal lesion and then place the leading end of the stent 2 cm or more proximal to the ledge. This allows the proximal end of the stent to be opposed to the aortic wall proximal to the lesion. If the stent is placed too low, it will be constrained by the lesion and may even pop down distal to the lesion before it can be fully dilated. Self-expanding stents have an advantage at larger diameters of 20 mm or more. In this range, self-expanding stents up to 28 mm are available that can be placed through an 11-Fr sheath. The corresponding balloon-expandable stent is a large Palmaz™ stent that is 5 cm in length and requires a large sheath, at least 12-Fr, which can accommodate the large diameter balloon and the stent simultaneously. Chapter 19 contains a detailed discussion of stent placement technique. After placement of a selfexpanding stent, balloon angioplasty fully dilates the stent and embeds it into the aortic wall. Treating a heavily calcified lesion poses a risk of rupture if overdilation is performed. The best approach in this case may be to place an oversized self-expanding stent that is well opposed to the aortic wall proximal and distal to the lesion, and then to gradually dilate the lesion with progressively larger diameter balloons. If the patient starts to experience severe pain, the procedure can be stopped safely, even if there is some residual stenosis. The challenge with self-expanding stents is that the trailing end of the stent lands in a less

Aorta 317

A

B

D

C

E

Fig. 23.4  Endovascular aortoiliac reconstruction. (A) A lesion that involves the infrarenal aorta and the proximal bilateral iliac arteries can be treated with a multistent reconstruction. (B) Sheaths and guidewires are placed through each iliac artery. The sheath intended for delivery of the aortic stent (the right side in this example) is advanced into the aorta. (C) The guidewire is withdrawn from the contralateral (left) side so that it will not be trapped behind the aortic stent. A stent is placed in the aorta. (D) The contralateral guidewire is advanced through the aortic stent and both sheaths are advanced. (E) Kissing stents are placed with their leading edges up to or even inside the aortic stent.

easily predictable location. Most aortic stents are placed from a femoral approach. The tip end of the stent will deploy first. The hub end, or trailing end, will deploy on the basis of the location of the whole stent; if the length requirements are misjudged, the lower end of the self-expanding stent could deploy in the iliac artery, rather than be proximal to the aortic bifurcation. When using a balloon-expandable stent, the operator must decide whether to advance the dilator and sheath through the aortic lesion. Initial recommendations included this maneuver so that the stent was not rubbed off the balloon catheter, as caused by friction as the catheter loaded with the stent passes through the lesion. If a hand-mounted stent is being used, as is usually the case with larger diameter stents, placing the sheath through the lesion in order to deliver the stent in a protected manner is

advisable. If a premounted stent is being used (i.e., a stent that is mounted on the balloon at the factory), this step is probably not necessary. If sheath passage is indicated and the residual lumen within the lesion is inadequate to permit sheath placement, predilation is required. A 9-Fr sheath requires at least a 3-mm lumen for placement. A stent mounted on a slightly undersized balloon may be satisfactory to place a balloon-expandable stent initially, as long as the stent expands enough to be held in place by the lesion. The stent can then be further expanded with a larger balloon. Some balloon expandable stents, such as the Palmaz™ stents, can be pushed beyond the limit of their stated diameters. However, the length will shorten further. For lesions longer than 2 or 3 cm, more than one balloon-expandable stent is used or a self-expanding stent is selected. After placement of a balloon-expandable stent,

318  The infrarenal aorta, aortic bifurcation, and iliac arteries

each end of the stent is dilated to be sure that it has assumed a cylindrical shape and that it is opposed to the wall of the aorta. If the lesion is close to the aortic bifurcation, the stent will tend to lean toward the side ­opposite the femoral access when deployed because  of the guidewire bias induced by coming from one side or the other. Consider placing a guidewire through a contralateral femoral access and using kissing balloons in the lower end of the stent. These balloons should be one-half the diameter of the stent. A 16-mm stent can be dilated with bilateral 8-mm balloons. Completion arteriography is performed by placing a flush catheter over the guidewire and administering contrast proximal to the stent site or by administering contrast retrograde through the sheath. The inferior mesenteric artery (IMA) frequently poses a challenge. Infrarenal aortic lesions often involve the vicinity of the IMA. In patients with visceral artery occlusive disease, the IMA may be a conduit for intestinal perfusion. Do not cover the IMA if it is not absolutely necessary. Stenting of the IMA is not typically performed, especially since it is small in caliber. If there is substantial plaque around the origin of a large IMA, consider performing selective arteriography of the superior mesenteric artery to clarify visceral perfusion. In addition, if a large IMA requires stenting over it, consider a self-expanding stent.

AORTIC BIFURCATION Aortic bifurcation stenoses that extend into the proximal common iliac arteries are treated with A

B

a kissing technique; access and treatment are performed through both iliac arteries (Figure 23.5). The plaque in this location is usually aortic plaque, concentrated especially along the posterior wall, that has extended into the common iliac arteries. A guidewire is placed through each femoral artery and advanced into the aorta. If the femoral arteries are pulseless, consider the techniques described in Chapter 2 for percutaneous puncture of a pulseless femoral artery. A micropuncture approach may be used, as described in the same chapter. Systemic heparin administration of at least 50 U/kg should be considered. If a complex reconstruction is planned or prolonged catheter time is expected, up to 100 U/kg of heparin should be considered. Starting guidewires are exchanged for an Amplatz Super Stiff® guidewire (0.035-inch diameter, 180-cm length) through a straight exchange catheter. Sheaths are selected as described in an earlier section. If balloon angioplasty with selective stenting is planned, 6-Fr, standard length access sheaths are adequate for balloons up to 8 mm in diameter, and 7-Fr sheaths are used for 9-mm or 10-mmdiameter balloons. Appropriate and equally sized balloons are advanced over the guidewires. The balloons are positioned so that the proximal radiopaque markers on each balloon overlap each other. The balloons are simultaneously inflated to the same pressure using dual inflation devices. This allows the entire aortic bifurcation and proximal iliac segments to be dilated simultaneously to the same pressure. This approach facilitates fracture of the cast of plaque that develops at the aortic C

Fig. 23.5  Management of a lesion in the aortic bifurcation using kissing balloons. (A) Bilateral guidewires are placed across a stenosis in the aortic bifurcation. (B) One balloon catheter is placed retrograde through each femoral artery and the proximal radiopaque markers are placed so that they overlap. (C) The equally sized balloons are inflated simultaneously to the same pressure to dilate the lesion in the bifurcation.

Aortic bifurcation  319

bifurcation and is often time circumferential or nearly so. The kissing balloon technique is usually performed with balloons from 6 to 10 mm in diameter. The size of the balloon must match not only the proximal common iliac arteries, but also the distal aorta. If there is significant narrowing in the distal aorta, it is important to remember that two separate balloons expanded simultaneously reach a large additive diameter. If 10-mm kissing balloons are used, the distal aorta must be 20 mm. If the aorta cannot quite accommodate that diameter, the balloons can be withdrawn just slightly to decrease the overlap between the two balloons in the distal aorta. In this case, most of the length of each balloon will be in the iliac artery rather than in the aorta. This avoids overdilating the very distal portion of the aorta. Note that when exchange guidewires are used, such as Amplatz Super Stiff® guidewires, the extra stiffness introduces an element of wire bias. When placed in a kissing fashion, the wires cross higher up, or more proximally in the infrarenal aorta. When placing kissing balloons side-by-side, the operator must take this adjustment into account in order to place the ­balloons in the correct position. If results are not satisfactory or residual stenosis is significant following angioplasty, or if the operator believes that these lesions are best stented, then kissing stent placement can be used to reconstruct the aortic bifurcation (Figure 23.6). This approach with kissing stent placement is common in most practices. This technique raises the aortic flow divider by a few millimeters to a centimeter. Either self-expanding or balloon-expandable stents may be used. Balloon-expandable stents provide the advantage of better hoop strength to treat these orifice lesions. In addition, the proximal ends of the stents, which create the new aortic flow divider, are easier to match up during deployment, since the accuracy of balloon-expandable stent placement is excellent. Self-expanding stents are a better choice if there is a lot of contour change, diameter mismatch, or tortuosity between the aorta and the proximal iliac arteries. The accuracy of placement has improved with the addition of markers on the ends of the stents, and the delivery catheters are also improved. Self-expanding stents, however, do not create a rigid flow divider if the bifurcation is being raised. Bilateral 6- or 7-Fr sheaths are usually adequate in size to handle

either self-expanding or balloon-expandable kissing stents. Matching balloon-expandable stents are selected based on artery size. Bilateral long sheaths, with dilators in place, are advanced across the lesion and into the distal aorta. Using fluoroscopy, the unexpanded stents are positioned so that the proximal radiopaque markers on the balloon catheters are parallel to each other but not quite overlapping, as they are for kissing balloons alone. Examine the stents under fluoroscopy to be sure that they have not migrated on their respective balloons. Migration of the stent a few millimeters along a balloon is common with hand-mounted and crimped balloon-expandable stents, but is rare with premounted stents. The sheaths are gently withdrawn to expose the bilateral stents. The proximal ends of the stents are usually 2–10 mm proximal to the aortic flow divider, depending on the amount of aortic plaque that must be treated. Road mapping may be used to outline the aortic bifurcation so that the stents are not placed more proximally than desired. Often, the aortic outline can be observed on plain fluoroscopy because of the presence of calcification. Careful consideration should be given to the length of distal aorta to be stented. If the lesion extends more than a centimeter up into the aorta, a separate aortic stent should be considered to secure inflow for the kissing stents at the bifurcation. Kissing stents are best deployed with an assistant, because balloon expansion must be performed simultaneously. After stent placement, the balloons are reinflated at more proximal and distal positions to be sure that the stents have fully expanded. The balloon catheters are removed. A flush catheter is placed through one side and completion arteriography is performed. Retrograde arteriography can also be performed through the sheath. Placement of self-expanding stents may also be performed. Predilating the lesion is advisable to gain lumen within which the stents can work. If the patent lumen is severely restricted, the stent may not expand sufficiently to allow placement of a poststent balloon angioplasty catheter. Because the metal mesh of the self-expanding stent does not have a lot of hoop strength, do not place exposed bare metal any higher into the aorta than is necessary. The stents are deployed gradually and simultaneously by the operator and an assistant and then postdilated with kissing balloons.

320  The infrarenal aorta, aortic bifurcation, and iliac arteries

A

B

C

D

E

F

Fig. 23.6  Kissing stents. (A) A significant residual stenosis remains after angioplasty. (B) Long access sheaths are advanced into the distal aorta. (C) The dilators are removed. (D) Equally sized balloons with mounted stents are advanced through each sheath. (E) The stents are deployed bilaterally by inflating the balloons simultaneously to the same pressure. (F) Kissing stents can raise the aortic flow divider to reconstruct the bifurcation.

Ipsilateral retrograde approach to the iliac artery  321

ILIAC ARTERY Iliac artery balloon angioplasty and stenting is the index endovascular procedure. It is a common procedure and has had a profound impact on the management of atherosclerotic occlusive disease. This procedure has a four-decade track record and has been refined and improved along the way. Technical modifications, such as stents, have dramatically expanded the complexity of the pathology that can be treated with endovascular intervention. It has superseded its surgical predecessor, aortofemoral bypass, and has largely replaced this operation. In appropriately selected patients, overall results are quite good and risks are acceptable. The durable results of this operation have been extrapolated to angioplasty of other vascular beds in the hope of justifying the broader use of endovascular intervention at sites where there is much less long-term evidence of success. Failure of this procedure can often be treated with secondary endovascular procedures and these rarely, if ever, take away later surgical options if they should become necessary. An iliac artery lesion can be approached either retrograde, through the ipsilateral femoral artery, or antegrade, through the contralateral femoral artery or an upper extremity puncture site (Figure  23.7). The location of the lesion determines the approach. Lesions of the aortic bifurcation, which are discussed in an earlier section, are treated with kissing balloons. Nonorifice lesions of the proximal common iliac artery are treated with a retrograde approach. There is usually only limited working room between the aortic bifurcation and the lesion to treat these with a contralateral up-and-over approach. Mid-iliac lesions, located from the middle section of the common iliac artery to the middle section of the external iliac artery, may be treated by using either an ipsilateral retrograde approach or a contralateral up-and-over approach. Lesions of the distal several centimeters of external iliac artery must be treated with an antegrade approach, usually through the contralateral femoral artery, since there is usually not enough working room to maneuver through an ipsilateral femoral access. A retrograde approach is performed by puncturing the common femoral artery distal to the iliac artery lesion. The femoral artery pulse may be diminished or absent, but it can usually be

accomplished with ultrasound guidance. If there is concern that the lesion is close to the inguinal ligament, this should be interrogated using ultrasound. The operator may also perform the access in the distal common femoral artery to gain more working room between the access site and the lesion. The ipsilateral retrograde approach is the most simple and direct once access has been obtained. The retrograde approach is useful for all iliac artery lesions except those in the very distal external iliac artery. Standard, single balloon angioplasty can be performed on iliac artery stenoses that begin a centimeter or more distal to the origin of the common iliac artery. Lesions that initiate in the orifice of the common iliac artery pose a risk of pushing plaque into the contralateral iliac artery during balloon angioplasty. The kissing balloon technique protects the contralateral side, even if there is no significant stenosis in the contralateral iliac artery origin. The challenging situation that often arises is a nonorifice proximal common iliac artery lesion that requires dilation and the adjacent iliac artery origin is mildly or moderately diseased. In these cases, if the origin of the common iliac artery requires dilation, kissing balloons should be used.

IPSILATERAL RETROGRADE APPROACH TO THE ILIAC ARTERY After the strategic arteriogram has been evaluated and the approach selected, the lesion is crossed with a guidewire if it has not already been traversed. When arteriography has been performed through the ipsilateral femoral artery, the guidewire has already been placed across the lesion just to achieve sheath access. When arteriography has been ­performed through a contralateral femoral puncture, the operator has the option of passing the guidewire over the aortic bifurcation or placing a retrograde wire through a new ­ipsilateral puncture site. If the lesion is complex, the approach is tortuous, the femoral access is difficult, or a multi­ level intervention is anticipated, consider placing a super stiff guidewire. Guidewires that are 0.035 inches in diameter and 150–180 cm in length are used. The appropriate sheath is selected and inserted using the same guidelines as described in the previous section (“Iliac artery”). Usually, a 6-Fr or 7-Fr sheath is adequate depending on what type of stent is anticipated. A radiopaque tip on the

322  The infrarenal aorta, aortic bifurcation, and iliac arteries

A

B

C

D

F

F

G

H

I

Fig. 23.7  Approaches to angioplasty of the iliac artery. (A) A very proximal common iliac artery lesion is present that requires treatment. (B) Proximal lesions are treated with kissing balloons, even if there appears to be minimal disease in the proximal contralateral iliac artery. (C) Proximal common iliac artery lesions that are distal to the iliac artery origin by a centimeter or more are also treated through an ipsilateral retrograde femoral approach. (D) This type of proximal common iliac artery lesion does not require a contralateral or kissing balloon. A balloon placed through the contralateral iliac artery and passed over the aortic bifurcation is not a good option for dilation of this lesion, since there is not adequate working room between the aortic bifurcation and the lesion. (E) Mid-iliac lesions are located between the mid-common iliac artery and the mid-external iliac artery and may be treated through a choice of multiple approaches. (F) These lesions may be treated through an ipsilateral retrograde femoral approach. There is adequate working room for an ipsilateral femoral access and the lesion is not too near the aortic bifurcation. (G) Mid-iliac lesions may also be treated through a contralateral approach. The guidewire and balloon catheter are passed over the aortic bifurcation. This may also be performed through an up-and-over sheath with the tip placed in the proximal common iliac artery. (H) Distal external iliac artery lesions are located with the result that there is usually inadequate working room for an ipsilateral femoral approach. (I) Distal external iliac artery lesions are best approached through the contralateral femoral artery using an up-and-over sheath.

Contralateral approach to the iliac artery  323

sheath is desirable. Heparin may be administered at 50–75 U/kg at the discretion of the operator. The length of the sheath is customized to the situation. The sheath should be long enough to pass the tip through the site of the lesion if needed. Therefore, for a retrograde approach to the aortic bifurcation, a 30-cm sheath is used. For an up-and-over approach to the distal, contralateral external iliac artery, a 45-cm sheath is used. When performing an ipsilateral approach to an external iliac artery lesion, a short 13-cm sheath is appropriate. There are occasions when it is appropriate to avoid placing a sheath over the aortic bifurcation. When the aortic bifurcation angle is very narrow, heavily calcified, or severely diseased, it may make more sense to avoid this ­maneuver. If the groin in which the sheath is inserted is heavily calcified or scarred, this will also add to the friction, poor trackability, and diminished maneuverability. After the sheath is inserted, arteriography can be performed through the sheath. The image intensifier is placed in the best position and the appropriate field of view used to obtain the optimal degree of magnification. The image intensifier is placed close to the abdominal wall. External iliac artery lesions and, sometimes, those in the distal common iliac artery are often well visualized using a contralateral anterior oblique projection. Radiopaque markers such as tape with 1-cm markers may be placed parallel to the guidewire on the patient’s abdominal wall after the location of the image intensifier has been established. This type of external marker is particularly helpful when a small field of view is used for more magnification, since this field size tends to exclude some of the surrounding bony landmarks. The linear centimeter length markers will not be accurate for exact length at the angioplasty site due to parallax. Stent length can usually be selected on the basis of the external markers and/or the length of the balloon used to treat the lesion. The balloon is selected and passed over the guidewire through the lesion (Figure 23.8). Common iliac artery angioplasty is performed with balloons between 6 and 10 mm in diameter. The balloons are usually 4 cm or longer in length and are mounted on 5-Fr catheters that are 75 or 80 cm in length. External iliac artery angioplasty is usually accomplished with 6–8-mm balloons. Occasionally, predilation with a lower-profile,

smaller diameter balloon is required. This may occur in the setting of a heavily calcified but preocclusive lesion. The balloon is centered so that the radiopaque markers straddle the lesion. The location of the worst stenosis should be along the central segment of the balloon. Iliac balloon angioplasty often causes flank discomfort, which should resolve when the balloon is deflated. Overdilation may cause rupture. Lesions of the external iliac artery, especially origin lesions, are more likely to result in dissection following angioplasty. Recanalized occlusions also frequently result in dissections. Completion arteriography can be performed through the sheath or with a flush catheter placed in the aorta proximal to the lesion. Stents are placed in most situations (Figure 23.9). There is more clinical experience and better results with stent placement in the iliac artery than at any other location. Most iliac artery lesions may be treated satisfactorily with either balloon-­expandable or self-expanding stents (see Chapter  19). Long lesions and arteries with significant taper or tortuosity are best treated with self-expanding stents. Focal lesions or lesions located at the origin of the common iliac arteries are treated with balloon-­ expandable stents. After the stent is selected, double-check the size of the sheath in place to be certain that it is adequate in caliber. The appropriately sized sheath is placed. The intended location for stent placement is identified by external markers, bony landmarks, or road mapping. The area to be covered by the stent may be slightly different than for the preceding balloon angioplasty, especially if there has been a dissection that requires treatment. Greater precision is required for stent deployment than for balloon angioplasty alone. After placement of the stent, additional balloon angioplasty is performed. A stent can be placed across the origin of the internal iliac artery and patency is usually maintained. (See Chapter 19 for a detailed discussion of the techniques of stent placement.)

CONTRALATERAL APPROACH TO THE ILIAC ARTERY The usual scenario for a contralateral approach is the setting of a contralateral puncture for strategic aortoiliac arteriography that then proceeds to treatment. The locations of the lesions are considered

324  The infrarenal aorta, aortic bifurcation, and iliac arteries

A

B

C

D

F

E

G

H

Fig. 23.8  Options for angioplasty of the iliac artery. (A) A significant right iliac artery stenosis requires treatment. (B) Aortography is performed through a contralateral femoral artery approach if the location of the lesion is not known precisely prior to arteriography. (C) A lesion of the middle iliac artery segment is dilated by passing the guidewire and catheter over the aortic bifurcation. (D) Another option is a second puncture site on the side ipsilateral to the lesion. If the location of the stenosis is known before arteriography, an ipsilateral retrograde puncture is used as the initial approach. (E) An access sheath is placed to simplify catheter passage for angioplasty. (F) A balloon catheter is passed across the lesion. (G) The balloon is inflated to dilate the lesion. (H) A contralateral catheter from the initial arteriography is used for completion arteriography.

and an approach selected (Figure  23.7). A  hookshaped catheter is placed in the ­infrarenal aorta and used to direct the guidewire over the aortic bifurcation. The guidewire is passed over the aortic bifurcation and into the contralateral femoral artery. The catheter is advanced into the femoral

region and the guidewire exchanged for a stiffer one, such as an Amplatz Super Stiff® guidewire, which is used to support the passage of a sheath over the aortic bifurcation. Heparin is administered. Insertion of a sheath over the aortic bifurcation is detailed in Chapter 14. These sheaths are

Contralateral approach to the iliac artery  325

A

B

C

D

E

Fig. 23.9  Placement of an iliac artery stent. (A) Aortic bifurcation lesions that spill over into the proximal iliac artery require kissing balloon stents. (B) A short, focal iliac artery stenosis is treated with a single expandable stent. (C) A lesion in a tortuous iliac artery is best treated with a flexible self-expanding stent. (D) A long iliac artery stenosis is treated with a single self-expanding stent. (E) A lesion of the distal external iliac artery is treated with a self-expanding stent. The sheath and delivery catheter are passed over the aortic bifurcation.

40 cm or longer in length and the caliber is selected in the same manner as for an ipsilateral retrograde approach, usually 6-Fr or 7-Fr. The up-and-over sheath has a radiopaque tip and can be advanced well into the contralateral iliac artery if the lesion is distal. The sheath should not be inadvertently advanced into the lesion. After sheath placement, repeat iliac arteriography through the sheath is usually performed after the image intensifier has been optimally positioned. External marking tape may also be placed. The appropriate balloon catheter is selected, as described in earlier sections regarding iliac ­arteries. Catheters 75–80 cm in length are usually

adequate to reach the contralateral groin. Balloon angioplasty is performed. The contralateral femoral area should be prepped into the field and the pulse is available for palpation. The balloon catheter is withdrawn but the guidewire position is carefully maintained. Completion arteriography is performed through the sheath. Self-expanding stents can be placed through a 6-Fr or 7-Fr sheath placed over the aortic bifurcation. The sheath must be held in place as the stent is deployed since traction on the stent delivery catheter tends to pull the sheath back. Balloonexpandable stents are a little more rigid and there is sometimes more friction when passing over the

326  The infrarenal aorta, aortic bifurcation, and iliac arteries

aortic bifurcation. If a balloon-expandable stent is desired, the following should be considered. Using a shorter, premounted stent helps to decrease ­friction. If the bifurcation is at a narrow angle, and especially if it is heavily calcified, the stent may not pass through the sheath. If there is doubt, take a good look at the up-and-over sheath under fluoroscopy and ensure that the course of the sheath is a smooth contour. Balloon-expandable stents that are covered are typically even a little higher in profile. Balloon angioplasty of nonorificial proximal common iliac artery lesions is difficult with an upand-over sheath in place since the tip of the sheath requires several centimeters of purchase in the proximal contralateral iliac system to maintain its curvature. One way to deal with this is to size up the sheath by one French size and use a stiff 0.014inch buddy wire to stabilize the sheath. Another maneuver that can be helpful is to place the sheath farther into the contralateral iliac artery than is necessary, advance the stent to the desired location, and then pull the sheath back just prior to deployment. This way, if the tip of the sheath has a poor hold on the contralateral proximal iliac artery, the stent can still be placed accurately. A short distance of clearance, about 1 cm, is required distal to the end of the sheath to accommodate the shoulder of the angioplasty balloon. It can be challenging to place stents into the proximal contralateral iliac system. Self-expanding stents have the problem that the second, or trailing, end of the stent may be deployed too close to the bifurcation and end up across the opening of the ipsilateral common iliac artery. Balloon-expandable stents are more accurate in terms of placement but they also have a significant conformance to wire bias that may tilt the balloon-expandable stent when deployed from the contralateral side.

SELF-EXPANDING VERSUS BALLOON-EXPANDABLE STENTS FOR THE AORTOILIAC SEGMENT Balloon-expandable stents were originally developed for the iliac arteries and they have been commonly used in the aortoiliac segment since their invention. Balloon-expandable stents have high crush resistance and when the stent is expanded to

a specific diameter using the balloon, the stent typically remains at that size. This is useful for l­ imiting residual stenosis. Balloon-expandable stents also may be useful in heavily calcified arteries. One concern is that with eccentric calcific lesions, aggressive expansion of a balloon-expandable stent could potentially push the plaque through the wall and rupture the artery. Self-expanding stents can be expanded more gradually. The other concern is that balloon-expandable stents tend to be relatively short and a plan must be made so that the stent is opposed to the artery wall proximal and distal to the lesion. Self-expanding stents have less radial force and are less able to stand up to calcific lesions. They have generally become more accurate to deploy, especially at the tip end of the stent. The hub end of the stent is not so easily predictable, but many self-expanding stents for the iliac arteries have minimal foreshortening. Self-expanding stents have a slightly lower profile and are less rigid than balloon-expandable stents. Self-expanding stents cover more artery length and are better in tortuous vessels. In general, there is data to support the use of either type of stent in the aortoiliac segment.

USE OF COVERED STENTS Both balloon-expandable and self-expanding covered stents are available for use in the aortoiliac arteries. Many of the same principles hold with the dichotomy between balloon-expandable and selfexpanding bare metal stents. When using covered stents it helps to aggressively predilate the lesion. After the covered stent is placed, it is again aggressively dilated. If a covered stent is not opposed to the artery wall or is occupying a significant portion of the artery lumen, it could provide less patency than with bare metal stents. In general, in the aortoiliac segment, there is more experience with balloonexpandable covered stents. There is data to suggest that with iliac artery lesions, balloon-expandable stents that are covered have better patency in the long run when compared with bare metal stents. Balloon-expandable covered stents have less flexibility. A slightly larger sheath is required and a higher cost involved. Coverage of the internal iliac artery should be avoided, and therefore careful measuring is required prior to placement.

Access related issues  327

ACCESS RELATED ISSUES Most aortoiliac treatment is performed using common femoral artery access. The iliac arteries can also be reached through upper extremity access through the brachial or radial artery. When there is an iliac artery occlusion, it is not unusual to perform access from both the femoral and the brachial arteries. In situations where kissing stents are required at the aortic bifurcation and bilateral femoral access is not possible, one stent can be placed using a femoral access and the other stent can be placed using an upper extremity access. In a normal sized man, a 90-cm sheath will usually reach the aortic bifurcation. Most iliac artery reconstructive work required can be performed with a 6-Fr sheath. Very often, bilateral femoral artery access is desirable if iliac artery lesions are at the aortic bifurcation or close to the bifurcation. When femoral artery access is not possible on one side or the other and brachial artery access

is suboptimal, another approach is retrograde access of the proximal superficial femoral artery. The artery should be relatively disease free. If the artery is 5 mm or larger and the access site is in the proximal few centimeters of the vessel, it can be closed with a closure device. If the superficial ­femoral artery is smaller or appears diseased, it is usually best to perform open exposure of the artery, undertake the procedure, and then close the artery with sutures.

One other access related concept is that when the iliac artery has a complicated lesion and it is being accessed retrograde, consider using a long micropuncture catheter. With the standard micropuncture catheter, the length is quite short, only a few centimeters. With a long micropuncture catheter, this can be placed all the way across the iliac artery lesion and then the wire of choice placed to control the lesion and establish the access.

24 The infrainguinal arteries: Advice about balloon angioplasty and stent placement INTRODUCTION Endovascular treatment of infrainguinal occlusive disease has become routine in recent years and has displaced surgical bypass in many situations. Balloon angioplasty and stents have significantly expanded the scope of patients who are eligible for treatment of infrainguinal occlusive disease. Several newer techniques have been developed or are being developed that could broaden the spectrum of treatment options and these are detailed in Chapters 20 and 25. Endovascular infrainguinal techniques are most efficacious in patients who are poor candidates for open surgery and in those with focal, short segment disease. In general, owing to the decreased morbidity of endovascular approaches, severe disease morphologies have been routinely taken on with these techniques. The long-term results of femoropopliteal angioplasty are not generally as good as those for surgery and they vary significantly based on the severity and extent of the occlusive disease. The current practice of infrainguinal intervention may differ substantially from institution to institution based on the level of enthusiasm for these techniques. Infrainguinal arteries may be approached through an ipsilateral antegrade femoral puncture or a contralateral femoral puncture followed by passage of the catheter over the aortic bifurcation. Chapter 2 describes how to perform an antegrade puncture. Chapter 9 provides methods for antegrade passage into the ipsilateral superficial femoral artery (SFA) and also for crossing the aortic bifurcation.

Chapter 11 details techniques for including the lower extremity in an arteriographic runoff study and for performing femoral arteriography and selective lower extremity and pedal arteriography.

SUPERFICIAL FEMORAL AND POPLITEAL ARTERIES Table 24.1 compares the over-the-bifurcation approach to infrainguinal disease with the ipsilateral antegrade approach. The ipsilateral antegrade approach provides better control of guidewires and catheters and excellent access to distal infrainguinal arteries. The inventory is simple, and once the guidewire is in the SFA, the procedure tends to be  fairly straightforward. The antegrade puncture can be a challenge and entering the SFA from the  common femoral artery often requires patience. Aortoiliac disease must be ruled out prior to this approach. The antegrade approach is not appropriate in severely obese patients due to difficulty with the angle of approach. It is not used in patients with significant common femoral or proximal SFA disease because of the proximity of the puncture site to the disease. In patients with SFA disease in the very proximal segment of the artery that requires treatment, it is best to avoid antegrade access because the working room is too limited. The over-the-bifurcation approach to infrainguinal disease from the contralateral femoral artery is advantageous in obese patients, those with proximal SFA disease, and those in whom aortoiliac disease must be evaluated prior to infrainguinal 329

330  The infrainguinal arteries: Advice about balloon angioplasty and stent placement

Table 24.1  Approaches to infrainguinal interventions: Ipsilateral approach versus up-and-over approach from the contralateral femoral artery Up-and-over approach

Antegrade approach

Puncture

Simple retrograde femoral

Catheterization

Up-and-over catheterization is challenging with tortuous arteries, narrow, or diseased aortic bifurcation; easier to catheterize SFA when going up-and-over Fair Need more supplies Flexible sheath, long balloon catheters Proximal SFA disease, CFA disease ipsilateral to infrainguinal lesion, obesity

More challenging, less working room Entering SFA from antegrade approach requires proximal femoral puncture and selective catheter

Guidewire/catheter control Catheter inventory Specialty items Indications

Excellent Minimal, shorter catheters None Intrapopliteal disease, patients with contraindication to up-and-over approach

Abbreviations: SFA, superficial femoral artery; CFA, common femoral artery.

intervention. The up-and-over approach reaches significant limitations in the treatment of contralateral tibial disease. The ankle and foot are too far to reach. The proximal and mid-tibial segments can be treated but the exchanges are quite lengthy. Entering the SFA is usually simple with the up-and-over approach, but tortuous aortoiliac anatomy or occlusive disease can make up-andover catheterization difficult. The up-and-over approach requires an inventory of longer catheters. Control of longer catheters and guidewires after they take multiple turns is not as satisfactory, but most cases can be performed using this method at the discretion of the surgeon.

IPSILATERAL ANTEGRADE APPROACH TO THE SUPERFICIAL FEMORAL AND POPLITEAL ARTERIES After antegrade puncture, the guidewire is directed into the origin of the SFA with a bent-tip selective catheter (see Chapter 9). The guidewire must be advanced far enough into the artery to secure the access. If a Glidewire® has been passed into the SFA, advance a 4-Fr or 5-Fr dilator over the wire and exchange it for a stiffer guidewire, and then pass the access sheath. If there is concern that the guidewire will cross the lesion prior to arteriography (e.g., with a lesion in the proximal or mid-SFA),

follow the advancing guidewire carefully using fluoroscopy, then pass a 4-Fr or 5-Fr dilator and perform femoral arteriography. A radiopaque ruler or external marker is placed on the drapes to mark the location of the lesion. A 4-, 5-, or 6-Fr sheath can be placed after secure guidewire access to the SFA has been obtained, depending on the intended procedure (Figure 24.1). After femoral arteriography, which includes distal runoff, the guidewire is passed antegrade through the lesion. Large collaterals are juxtaposed and often parallel to femoropopliteal lesions and the directional guidewire tends to select them. A steerable guidewire is preferred. After the guidewire is placed, a repeat arteriogram through the side arm of the sheath is obtained to ensure that the lesion has been appropriately crossed and that the wire is in the correct location distal to the lesion. Perigenicular collaterals tend to run parallel to the popliteal artery and it is possible to pass the guidewire into one of these without realizing that it is not in the correct location. It may look appropriate on plain fluoroscopy, but must be confirmed angiographically. Heparin is administered for infrainguinal angioplasty. Consider 50–75 U/kg for simple, focal lesions. In treating more complex lesions, 100 U/kg may be more appropriate. This is discussed further in Chapter 25. When the catheter is in the artery for a short time and flow is interrupted for only

Ipsilateral antegrade approach to the superficial femoral and popliteal arteries  331

A

D

B

C

E

F

G

H

Fig. 24.1  Balloon angioplasty of the superficial femoral and popliteal arteries. (A) A stenosis of the SFA is deemed suitable for angioplasty. (B) Either an antegrade or up-and-over approach is reasonable for access. The stenosis is approached antegrade through an ipsilateral femoral artery puncture or across the aortic bifurcation. (C) An ipsilateral antegrade femoral artery puncture is performed. The guidewire is placed across the stenosis. (D) A hemostatic access sheath is placed over the guidewire into the proximal SFA. (E) Femoral arteriography through the side arm of the sheath evaluates the lesion and confirms the guidewire position. (F) The angioplasty balloon is selected and passed through the stenosis. (G) The stenosis is dilated. (H) The balloon is removed but the position of the guidewire is maintained. Completion arteriography is performed through the side arm of the sheath.

332  The infrainguinal arteries: Advice about balloon angioplasty and stent placement

Table 24.2  Supplies for antegrade femoral approach to infrainguinal intervention Length Guidewire

Catheter Sheath Balloon

Starting/selective guidewire

Bentson

145 cm

Selective guidewire

Glidewire®

180 cm

Exchange guidewire Selective Exchange Access

Rosen Kumpe Straight or angled Standard hemostatic access Balloon diameter Balloon length

180 cm 40 cm 70 cm 12 cm

Balloon angioplasty catheters

Catheter shaft Stent

Self-expanding

Stent diameter Stent length Delivery catheter length

Diameter 0.035 inch (steerable, shapeable tip) 0.035 inch (angled tip) 0.035 inch (J tip) 5-Fr (short, bent tip) 5-Fr 4-Fr, 5-Fr, 7-Fra 4, 5, 6 mm

2, 4 cm and longer, up to 20 cm 75 cm; distal tibial may require 90 cm 40–200 mm 80 cm

5, 6, 7 mm 40–200 mm

a

Use 4-Fr or 5-Fr sheath for tibial balloon angioplasty with 3.8-Fr catheters. Use a 5-Fr sheath for balloon angioplasty up to 6 mm on a 5-Fr shaft. A 6-Fr sheath is required for stent placement using a 0.035-inch system.

a few seconds, a lower dose of heparin usually suffices. Consider higher heparin doses for more complex cases. In cases that will include drugcoated balloon (DCB) angioplasty, the balloon will be inflated for 120–180 seconds at a minimum and this may be required multiple times. Anticoagulation should be more complete in this situation to avoid thrombus formation. Guidewires from 145 cm to 180 cm in length are used with angiographic catheters that are 40–70 cm in length (Table 24.2). Balloon angioplasty catheters that are 75 or 80 cm in length are adequate to reach the mid-tibial level in most patients through an antegrade approach. If a longer balloon catheter is used, a longer guidewire may be required. Once the intended site of intervention is marked with an external marker or road map, the distance can be measured outside the limb to estimate the length required. Balloon diameters range from 4 mm to 7 mm in the SFA and 3 mm to 6 mm in the popliteal artery. A 5-Fr sheath will accommodate balloons up to 6 mm in diameter. If there is doubt about sizing, it is usually safest to begin with a balloon of less diameter than will probably be required, rather than oversize. Balloon-expandable

stents are not routinely appropriate for the SFA and p ­ opliteal arteries. Most stents in this setting are self-expanding, either standard nitinol tubes or woven nitinol. Self-expanding stents may require anywhere from a 4-Fr to a 6-Fr sheath depending on the selected stent. Self-expanding covered stents, such as a Viabahn®, can be placed through a 6-Fr sheath, as well, for routine sizes. Larger sized stents used to treat popliteal aneurysmal disease require a sheath of 8-Fr to 10-Fr. An issue that comes up regularly, especially with lesions of the proximal and mid-SFA treated through an antegrade approach, is that the operator has to decide if there is enough distance between the access site and the lesion to support sheath insertion. If there is not enough distance, the lesion must be crossed and a stiffer wire inserted through it in order to support sheath insertion. The tip of the guidewire is usually placed in the distal popliteal artery. If the balloon angioplasty site is below the knee, the guidewire should be advanced into the tibial arteries. During exchanges of catheters, occasional fluoroscopy of this area is performed to ensure that the guidewire is not allowed to move from its position. Always confirm

Ipsilateral antegrade approach to the superficial femoral and popliteal arteries  333

the guidewire position in the true lumen of the artery distal to the lesion prior to performing balloon angioplasty. Once the balloon angioplasty catheter is in place, the balloon is inflated while observing it using fluoroscopy. Following deflation, the balloon is withdrawn and completion arteriography is performed through the side arm of the sheath. If a 5-Fr balloon catheter shaft is used with a 5-Fr hemostatic sheath, the sheath lumen is completely obstructed by the catheter. The balloon catheter must be completely withdrawn before arteriography is performed. If the sheath is 6-Fr or larger, the balloon catheter is withdrawn from the angioplasty site and contrast is injected around the shaft of the catheter through the side arm of the sheath. When a deflated 6-mm diameter balloon is removed through a 5-Fr sheath, the fit is very snug. The balloon should be aspirated continuously with A

B

a syringe to decrease its profile, and the sheath must be manually secured. Completion arteriography is used to assess the size of the lumen after balloon angioplasty and the flow through the intervention site and to look for extravasation, contrast trapping in the vessel wall, evidence of dissection, or significant residual stenosis. Best results are obtained with angioplasty of focal, critical lesions. Long-segment femoropopliteal angioplasty is complicated by a higher incidence of acute occlusion, dissection, and lower long-term patency rates. Angioplasty of the SFA routinely produces evidence of a dissection plane on completion images. A stent is placed if a significant dissection has occurred (Figure 24.2). A 6-Fr sheath is required for self-expanding stent placement using a standard 0.035-inch system. If a stent must cross the C

D

E

Fig. 24.2  Stent placement in the superficial femoral artery. (A) Postangioplasty dissection is present on completion arteriography. (B) A self-expanding stent is delivered to the site. (C) The stent is deployed from the distal end of the lesion to its proximal end. (D) After poststent balloon angioplasty is performed, the stent reaches its appropriate profile. (E) Completion arteriography is performed through the sheath while maintaining guidewire access.

334  The infrainguinal arteries: Advice about balloon angioplasty and stent placement

knee joint, a self-expanding stent is appropriately flexible. Woven nitinol stents have unique qualities of flexibility and show promise for use in the distal SFA and popliteal arteries. A standard 12or 13-cm length access sheath can be used with an 80-cm delivery catheter. The more complex the lesion (e.g., long occlusion, heavily calcified, extending from SFA to popliteal artery), the more helpful it is to have a longer sheath that extends close to the location of the lesion in order to support crossing and stent delivery. The standard self-expanding nitinol stent is oversized slightly in comparison to the reference vessel diameter at the intended placement site, usually by a millimeter, but hopefully no more than that. Significant oversizing has been associated with intimal hyperplasia and restenosis. Self-expanding nitinol stents are deployed from the “tip” end to the “hub” end. The “tip” end (leading end) of the stent can be deployed with accuracy and is allowed to flare just beyond the lesion. The delivery catheter for self-expanding stents typically has a pin-and-pull or ratchet delivery mechanism. After the leading end is deployed, the delivery catheter is held steady so that the stent is not abnormally elongated during deployment. The ratchet or pin-and-pull mechanism removes a covering membrane that constrains the stent. After uncovering, the stent takes its intended shape within the artery. Poststent balloon angioplasty is routinely performed and often reveals a residual waist that is pressing or impinging on the stent from the outside. Completion arteriography is performed through the side arm of the sheath. Standard self-expanding nitinol stents are known for ease of placement, longer available lengths, flexibility within the artery, and contourability along the artery. It is possible to crush balloonexpandable stents with external compression, so these are generally avoided. Woven nitinol stents may also be used in the SFA and popliteal arteries. The advantage is the hoop strength or crush resistance and the flexibility. Hence, they are becoming a preferred stent for heavily calcified segments and highly flexible segments, such as the distal SFA and popliteal arteries. The stent is not oversized to the artery but is selected on a one-to-one basis with the size of the lumen. Therefore, the availability of these stents is in half sizes (e.g., diameters of 4.5  mm, 5.0 mm, 5.5 mm, etc.). The artery must be well prepared by creating a lumen adequate for the rings of the stent to fully form when deployed. This usually

requires aggressive balloon angioplasty prior to placement, with a balloon that is 0.5–1.0 mm larger than the diameter of the stent. The operator controls the cadence at which the rings or segments of the stents are deployed. Woven nitinol stents have excellent results when deployed to the intended nominal size. The location of the “tip” end may be adjusted with great accuracy, but the location of the trailing end (“hub” end) of the stent can be very challenging to predict. After deployment, poststent placement balloon angioplasty is optional. DCB angioplasty is discussed in Chapter 20. In the context of SFA and popliteal artery treatment, there are multiple approved DCBs. It is appropriate to avoid stenting or scaffolding, as far as possible, in the hope of maintaining long-term patency on the basis of the medication and avoiding the longterm chronic inflammatory stimulus of an irritating implant. Therefore, the DCB angioplasty technique is different from the standard balloon angioplasty technique for the superficial femoral and popliteal arteries, as it is intended to deliver medication and minimize dissection. If scaffolding is required, it should be performed with the most inert possible implant and should be performed in a focal manner so as to avoid a “full metal jacket” approach.

UP-AND-OVER APPROACH TO THE SUPERFICIAL FEMORAL AND POPLITEAL ARTERIES Selective catheterization of the aortic bifurcation and antegrade passage of a catheter into the contralateral iliac artery are discussed in Chapter 9. Details of the passage of an up-and-over sheath are presented in Chapter  14. Equipment required for an up-and-over approach to infrainguinal intervention is listed in Table 24.3. Contralateral intervention is performed with an up-and-over sheath. This permits a stable access and the ability to perform angiography whenever required. Keeping the access site remote from the treatment site permits the operator to isolate these two variables and helps to avoid a cascade of complications if there is a problem at either the access site or the treatment site. A challenge to the use of an up-and-over approach is the presence of a narrow, very proximal (well above the usual L4-L5 position), or heavily calcified bifurcation. These factors generally resist straightforward placement of the sheath. One disadvantage of the up-and-over

Up-and-over approach to the superficial femoral and popliteal arteries  335

Table 24.3  Supplies for up-and-over approach to infrainguinal intervention

Guidewire

Catheter Sheath Balloon

Stent

a

Starting Selective

Bentson Glidewire® Glidewire® Exchange Supra Core® Amplatz Super Stiff® Flush/selective Omni® Flush Exchange Straight Selective sheath Up-and-over Balloon angioplasty Balloon diameter catheters Balloon length

Self-expanding

Catheter shaft Stent diameter Stent length Delivery catheter length

Length

Diameter

145 cm 150 cm 260 cm 180 cm 180 cm 65 cm 90 cm 45, 55, 70 cm

0.035 inch 0.035 inch (steerable) 0.035 inch (steerable) 0.035 inch 0.035 inch 4-Fr 5-Fr 6-Fr, 7-Fr 4, 5, 6 mm

4 cm and longer, up to 20 cm 75, 90, 120 cma 5, 6, 7 mm 40–200 mm 80, 120 cm

A 75-cm catheter shaft for balloon angioplasty reaches to mid-SFA in an average sized person. Longer catheters are required for a contralateral approach to distal SFA, popliteal, and tibial intervention.

approach to infrainguinal treatment is the distance to the target site. If tibial intervention is included in the procedure, the distance to the target site may exceed the available catheter lengths. However, generally this is a widely applicable technique, a variety of acceptable sheaths are available, and a sheath can almost always be placed. The length of the sheath can be estimated based on the length of diagnostic catheter required to reach close to the lesion. Usually, it is best to place the tip of the sheath as close to the lesion as p ­ ossible. Exceptions to this general rule are as follows. If the lesion is a simple focal stenosis, treatment can be performed in a straightforward manner without the extra leverage of having the sheath tip nearby. If the superficial femoral and/or popliteal arteries for treatment are smaller in diameter, such that the sheath may occlude forward flow, the operator has to take this into account and decide whether this is best. Additional anticoagulation may be required, and extra friction will be encountered both during insertion and removal of the sheath. Lastly, if the aortic bifurcation is somewhat hostile to cross, sometimes the sheath can be a challenge to remove due to multiple points of friction. If balloon angioplasty alone is anticipated, a 4-Fr or 5-Fr sheath is adequate for angioplasty

up to 6 mm in diameter. However, if atherectomy, stent placement, or other additional maneuvers are included, even DCB angioplasty, it is better to have a 6-Fr sheath. This upsizing of the sheath makes the access insertion site larger, but any additional challenge posed by this is typically mitigated by use of a closure device. The limiting factors on sheath caliber are usually the quality of the aortic bifurcation segments and the quality of the common femoral artery used for access. Occasionally, one or both of these will be diseased to the point where upsizing from a 5-Fr to a 6-Fr sheath is avoided in order to minimize the risk of a complication. If stent placement is anticipated or it becomes necessary to treat a postangioplasty complication, a 6-Fr sheath is required to place a self-expanding stent using a 0.035-inch guidewire system. If the target treatment site is in the very proximal SFA, the best way to place the sheath is to advance the guidewire into the profunda femoris artery rather than into the SFA. A stiff exchange wire is then exchanged so that the up-and-over sheath can be advanced into the common femoral artery just proximal to the lesion. The exchange guidewire is removed, the wire intended for crossing the lesion advanced, and the sheath used for angiography to guide the crossing of the lesion.

336  The infrainguinal arteries: Advice about balloon angioplasty and stent placement

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Fig. 24.3  Balloon angioplasty of the femoral and popliteal arteries through an up-and-over approach. (A) An SFA lesion is identified. (B) A guidewire is introduced through the contralateral femoral artery and placed over the aortic bifurcation. The guidewire may be placed in either the profunda femoris artery or the SFA. If the guidewire is placed in the SFA, care should be taken to prevent unintended encounters between the wire and the lesion during sheath placement. (C) An up-and-over sheath is placed and arteriography performed. (D) The guidewire is advanced across the lesion. (E) Balloon angioplasty is performed. (F) Completion arteriography is performed through the sheath.

If the target treatment site is in the distal SFA or popliteal artery, it is usually best to advance the initial catheter into the SFA directly and then place the exchange guidewire in the SFA for sheath advancement. Femoral arteriography may be performed through the side arm of the sheath (Figure 24.3). If the amount of contrast administration must be limited, a straight or angle tip catheter may be passed through the sheath and into the proximal SFA and an arteriogram obtained in that manner. The exchange guidewire over which the sheath has been passed is exchanged for a steerable guidewire, usually a 260-cm angle tip Glidewire®, which is used to cross simple infrainguinal lesions. A variety of crossing techniques may be used to cross more complex lesions, including use of 0.014inch or 0.018-inch wires, chronic total occlusion

catheters, or re-entry catheters, and these are covered in Chapters 20 and 25. Heparin is administered: 50–75 U/kg for simple lesions and 100 U/kg for complex lesions. The length of the balloon catheter shaft is selected based on the location of the lesion. The proximal SFA, and possibly the mid-SFA, can be reached with a 75- or 80-cm length catheter; in a patient of short stature, it will reach the mid-SFA. More distal lesions require a 90- or 120-cm catheter. When tibial arteries are approached using an up-and-over approach, 150-cm length balloon catheters are available and will reach to the distal tibial level in the average sized person. An estimate of the required catheter length can be made using the straight exchange catheter, which is used to exchange the guidewires. The exchange catheters are usually 65–120 cm in length. Care must

Access related issues: Difficult up-and-over approach to the superficial femoral and popliteal arteries  337

be taken to maintain the guidewire in a stationary position so that its leading edge does not advance into the distal infrageniculate runoff arteries during passage of long catheters. Inadvertent wire advancement can occasionally result in damage to one of the runoff vessels or unguided passage across a more distal lesion, with resulting damage. Intermittent fluoroscopy is required. It is also usually helpful to mark the outside location of the wire and to refer back to it during the procedure. After balloon angioplasty, the catheter is withdrawn while the guidewire is maintained in place. Completion arteriography is performed through the side arm of the sheath. The angioplasty site is assessed in the same way as described in an earlier section. Most self-expanding stents are delivered on catheters that are either 80 cm or 120 cm in length. The required distance may be estimated based on the length of the balloon catheter required. After placement of a self-expanding nitinol stent, balloon angioplasty is performed along the length of the stent followed by completion arteriography.

ACCESS RELATED ISSUES: DIFFICULT UP-AND-OVER APPROACH TO THE SUPERFICIAL FEMORAL AND POPLITEAL ARTERIES There are multiple ways in which the up-and-over access can be challenging. If the infrarenal aorta is short and the aortic bifurcation is located above the L4-L5 junction, the angle of the aortic bifurcation tends to be quite narrow. In addition, if the aortic bifurcation is highly calcified, the catheter may pass but a stiffer exchange wire may not, due to the rigidity of the structures. Lastly, if there is significant friction along the path, either from the access site itself (due to a scarred access vessel) or if there are numerous untreated lesions in the approach iliac artery, or if there is significant tortuosity, all of these can be problematic and add challenge to the placement of an up-and-over sheath. Catheterization of the aortic bifurcation is discussed in Chapter 9 and Figures 9.10–9.12 demonstrate some techniques for succeeding in this endeavor. In the following outline, different techniques are discussed that can help resolve the challenging up-and-over access. There may be a challenge with catheter placement in the contralateral iliac artery, with advancement of an exchange guidewire over the aortic bifurcation, or with passage of the sheath

over the exchange wire, or with all three of these important steps. The up-and-over catheter may be very difficult to place in some patients. In patients with ipsilateral tortuosity the hook-shaped catheter head may consistently point to the wrong direction or it may turn 360 degrees when attempting to point it toward the contralateral iliac artery. In this case, the guidewire can be passed into the catheter and be poised at the tip of the catheter for advancement. The catheter is turned, not so that it points to the contralateral side directly, but at least so that it is not pointing to the ipsilateral side. The wire is then advanced into the contralateral iliac artery. A torque device to steer the Glidewire® is helpful. After the wire has entered the contralateral iliac artery, the catheter head is slowly withdrawn while it is untwisted under fluoroscopic visualization. Two other maneuvers are worth mentioning. If the catheter consistently assumes the wrong orientation, the catheter can be advanced further into the infrarenal aorta. Even as the catheter tip points toward the ipsilateral side, when the wire is advanced, it usually bounces off the ipsilateral wall and goes into the contralateral iliac artery. The catheter must be rotated until it points to the correct side. With the catheter being looked at under fluoroscopy, it is rotated slightly to see if the guidewire wrap is getting better or worse; this is how to establish which way the catheter must be rotated. Another maneuver is as follows. In some patients it makes sense to advance the hook-shaped or Omni® Flush catheter only to the level of the ipsilateral common iliac artery and then advance the wire for shaft stiffness. Then advance the catheter so that the tip itself is leading into the contralateral side. This is particularly helpful when the infrarenal aorta is aneurysmal or has significant mural thrombus that must be avoided. Yet another option is to use a catheter with a tighter curve at the tip, such as a RIM catheter. In some patients, after the guidewire is advanced, the hook-shaped catheter is unable to advance over it. In this case it usually means that the irregularity of the contour of the catheter where the hook-shaped tip is located is catching on some calcific plaque. Consider carefully removing the Omni® Flush catheter and advancing a straight or angled 4-Fr or 5-Fr Glidecath®. If the hook-shaped catheter head goes over the aortic bifurcation but the wire repeatedly goes

338  The infrainguinal arteries: Advice about balloon angioplasty and stent placement

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Fig. 24.4  Adjusting the up-and-over catheter to obtain the desired trajectory for the wire. (A) A hookshaped, Omni® Flush-style catheter is used to cannulate the contralateral iliac artery over the aortic bifurcation. (B) As the catheter is withdrawn to the aortic bifurcation, the shape of the catheter head changes significantly as it rests on the flow divider. The angle of the curve is much wider at this point. This angle can be used to direct the guidewire into different trajectories. (C) If a slight amount of traction is placed on the catheter, the tip of the catheter points toward the outer wall or outer curve of the iliac artery. (D) If the catheter is advanced slightly and the hook shape is allowed to return to a little closer to its normal configuration, the tip of the catheter points the wire toward the inner wall or in a curve of the iliac artery. This can be helpful when the wire immediately encounters a lesion in the proximal common iliac artery that must be crossed.

into the internal iliac artery or consistently hangs up on a plaque, consider adjusting the hook shape as it sits on the bifurcation to point the wire in a slightly different direction. A slight traction on the catheter usually allows the pointing tip of the catheter to follow the external wall of the iliac artery (Figure 24.4). In some patients, ipsilateral iliac artery occlusive disease, which the operator may prefer to treat secondarily, must be treated primarily, because it is causing a significant decrease in maneuverability or increased resistance to sheath placement. Therefore, the ipsilateral iliac artery occlusive ­disease may be treated before contralateral access is achieved. In this case a stiff wire is inserted on the ipsilateral side, extending into the infrarenal aorta, and a 6-Fr or 7-Fr sheath advanced retrograde into the iliac artery. After treatment of the iliac artery, the sheath can then be advanced so that its tip is in the proximal ipsilateral common iliac artery. The hook-shaped catheter is then passed through the sheath and used to cannulate the contralateral side. The ipsilateral sheath is used as a platform for cannulation of the aortic bifurcation. After the catheter has been advanced to the ­contralateral side, if it is a difficult aortic bifurcation, it is usually best to advance it as far as possible. It can be advanced into either the SFA and popliteal artery or into the profunda femoris artery. After that, a stiff exchange wire is advanced. Stiff exchange wires may include an Amplatz Super

Stiff® or a Supra Core® guidewire. These are typically 0.035-inch diameter guidewires. They are stiff in the shaft but have a variable length of floppy tip so that the leading wire tip will pass easily through significant curvature before the stiff part of the wire arrives. In the usual scenario, the guidewire advances to the desired location in the contralateral limb so that the sheath can be easily advanced. In some patients who have a narrow aortic bifurcation or a severely calcified bifurcation that is very stiff, the guidewire will not advance because the anatomy will not relax enough to the shape that the stiff wire is imposing. In this case, consider advancing a stiff Glidewire®. Sometimes, the exchange wire will advance more readily if any tortuosity or resistance in the ipsilateral iliac artery is removed. This can be done by placing a sheath along the length of the diseased or tortuous ipsilateral iliac artery. After the guidewire is placed, the sheath is advanced over it. In a situation of difficult access, it usually makes sense to advance the sheath under fluoroscopic guidance so that if the progress stops, the location can be identified. This is sometimes a location that can be dilated with a balloon placed out ahead of the sheath. Another option with a difficult sheath passage is to use a longer dilator for the sheath and advance that first and then telescope the sheath over it. This is demonstrated in Chapter 14 (Figure 14.8). An example would be to use a 65-cm dilator for a 45-cm sheath. The dilator

Access related issues: Difficult up-and-over approach to the superficial femoral and popliteal arteries  339

extends well beyond the tip of the sheath. When the dilator cannot be advanced any further, the sheath is advanced (telescoped) over the dilator. Another option is to use a sheath-within-asheath, as demonstrated in Figure 24.5. The sheath of choice is advanced as far as it can be. If the platform is not adequate, a smaller sheath can be passed through it and this will usually pass further. In general, for a sheath-within-a-sheath approach, the

A

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sheath size differential needs to be 2  French  sizes (i.e., a 5-Fr sheath will go through a 7-Fr sheath and a 4-Fr sheath will go through a 6-Fr sheath). Figure 24.5 also shows how this is most commonly used. In patients who require treatment for multilevel occlusive disease, a 6-Fr or 7-Fr sheath is used to treat the femoropopliteal segment. If the infrageniculate arteries also require treatment, a longer, lower-profile sheath (4-Fr or 5-Fr) is passed through

B

D

Fig. 24.5  Sheath-within-a-sheath to reach more distally. (A) The sheath is passed into a difficult aortic bifurcation. In this case the tip of the sheath only passed into the proximal contralateral iliac artery. (B) Because the original sheath would not advance without difficulty, and additional support is required, a second smaller sheath is passed through the first sheath. In many situations this platform is adequate for treatment. Sometimes, the original sheath will advance slightly further over the second sheath in a telescoping fashion if more support is needed. (C) The situation in which a sheath-withina-sheath is most commonly used is when a larger sheath is required for iliac artery or SFA treatment, but additional more distal support is needed to treat smaller runoff vessels. (D) Additional treatment is required of the tibial arteries. A smaller sheath, usually a 4-Fr or 5-Fr sheath, is advanced through the original existing platform sheath.

340  The infrainguinal arteries: Advice about balloon angioplasty and stent placement

the first sheath to create a better platform for more distal treatment. If the sheath of choice will not go over the bifurcation or cannot be advanced to the desired location, consider using a smaller sheath altogether. Many different types of interventions can be performed using a modified plan and a smaller sheath than was the operator’s original intent. Another option is to advance a percutaneous transluminal angioplasty (PTA) balloon over the wire and ahead of the sheath. The PTA balloon is inflated in a safe location that is appropriately sized to the balloon and the structure is used as an anchor over which to advance the sheath (Figure 24.6). There is one other maneuver worth considering but is rarely required. Obtain a 3 mm or 4 mm diameter balloon, 40–80 mm in length and 0.035-inch diameter compatible so that it has a 5-Fr shaft (Figure 24.7). If the sheath tip stalls on the proximal ipsilateral iliac artery or over the bifurcation, or along the very contralateral proximal iliac artery, the lower-profile balloon can be advanced ahead of the sheath. The balloon is then gently inflated to about 2 atm of pressure. As the balloon is deflated the sheath is advanced over the deflating balloon. This type of inchworm approach can be used to get the sheath tip past high-risk areas and is relatively atraumatic. Lastly, it is better to change the approach, or perhaps not do the case, than to have an access-related complication before the intended treatment is even A

B

attempted. Access-related complications for upand-over access could include embolization, vessel rupture, or iliac dissection. Management of these complications is considered in other sections, but it is better not to have them. If more than 5 minutes have been spent attempting to traverse the aortic bifurcation, consideration should be given to selecting an alternative approach.

Strategy: The difficult up-and-over access ●●

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Hook-shaped catheter will not point to the contralateral side: pass the wire then untwist the catheter; do not attempt to turn the catheter to the perfect direction. Catheter on the bifurcation but wire will not advance to the correct location: adjust the hook-shaped catheter to affect the wire trajectory (Figure 24.4). Very narrow aortic bifurcation: use a catheter with a tighter curve, such as a RIM catheter. After cannulation of contralateral iliac artery, put the wire as far down as possible. Dilate the ipsilateral iliac artery, if needed. Use a longer dilator, then telescope the sheath over the dilator (see Chapter 14, Figure 14.8). Use a sheath-within-a-sheath if the original sheath choice will not pass (Figure 24.5) Downsize sheath: if original sheath choice is not tolerated by the system, sometimes the C

Fig. 24.6  Using an angioplasty balloon to anchor the sheath. (A) A sheath and dilator are advanced over a difficult aortic bifurcation, but the sheath will not advance beyond the common iliac artery. (B) A PTA balloon catheter is advanced. The balloon is advanced to a section of normal artery located more distally, in the distal external iliac artery, the common femoral artery, or the proximal SFA, with the balloon sized for the chosen anchor location. (C) The balloon is inflated to anchor and stabilize the wire. The sheath is advanced over the 5-Fr balloon catheter, which has been stabilized by inflating the balloon.

Tibial artery occlusive disease: Angioplasty and stenting  341

A

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Fig. 24.7  Advancing the sheath over a deflating balloon. (A) A heavily calcified aortic bifurcation poses a significant challenge to establishing an adequate platform. The guidewire has been placed across the aortic bifurcation. (B) When the sheath is advanced, the tip of the sheath only goes to the flow divider and then stops. (C) A balloon catheter is advanced. This is a 3-mm or 4-mm diameter balloon on a 5-Fr shaft that is compatible with a 0.035-inch diameter guidewire. (D) The balloon is inflated gently, to approximately 2 atm of pressure. This has the effect of centering the guidewire and pulling it gently away from the jagged wall of the artery. (E) As the balloon is slowly deflated the sheath is advanced gently over it in an inchworm fashion.

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plan can be altered to allow the case to be done through a one size smaller sheath. Use a PTA balloon to anchor the wire so that the sheath can be advanced (Figure 24.6). Use a 3- or 4-mm balloon on a 5-Fr shaft and do incremental advancement by advancing the stalled sheath over the deflating balloon (Figure 24.7).

TIBIAL ARTERY OCCLUSIVE DISEASE: ANGIOPLASTY AND STENTING Tibial revascularization is a rapidly growing part of endovascular practice. Tibial artery disease causing limb-threatening ischemia may present as a single level of disease or as multilevel disease that

also involves several inflow segments, including the femoropopliteal arteries. In the case of multilevel disease, all inflow arteries must be treated first, either in the same setting or at an interval prior to tibial artery revascularization. In patients with rest pain or superficial ulcers, inflow treatment is often all that is required to manage the patient’s ischemia, without tibial artery ­intervention. The long-term success of most catheter-based tibial procedures is poor, therefore it is not often used in patients with claudication. Over recent years, a wide variety of tibial artery pathologies have become manageable with catheter-based techniques. Occasionally, focal tibial artery lesions require treatment to ameliorate limb-threatening ischemia. In this situation,

342  The infrainguinal arteries: Advice about balloon angioplasty and stent placement

there may be focal lesions in multiple tibial arteries or long lesions in some vessels and focal lesions affecting single vessel runoff. The more common situation is the presentation of long lesions, up to 25 or 30 cm, and a large proportion of these are likely to be occlusions. The ability to cross long tibial artery occlusions has made this a viable ­ therapy in a large segment of patients who require revascularization for limb salvage. Many of the principles, techniques, and devices required to make tibial procedures a reality have been adopted from other vascular beds. The best factors suggesting success are in cases where the foot damage is minimal and also where the runoff into the foot is intact. Patients with major foot damage, exposure of vital structures, or with severe intrapedal occlusive disease have a lesser chance of salvage with endovascular approaches. Because endovascular revascularization rarely provides the

A

robust level of perfusion that results from bypass to the tibial arteries, it is often desirable to open more than one tibial artery. No matter whether the perfusion of the foot is robust or not, the foot should be managed aggressively to achieve wound healing. The long-term patency of tibial angioplasty and stenting may be only fair, but limb salvage is often achieved without bypass. After revascularization, monitoring of the progress of the wound is essential since early failure is common. When this occurs, the opportunity for bypass or repeat endovascular treatment may present itself in a narrow window during which the wound healing is not progressing. Whenever possible, the tip of the sheath is placed just proximal to the area of treatment. Ideally, the sheath tip is placed in the popliteal artery so that minimal contrast can be used and the platform provides good support for the intervention.

B

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Fig. 24.8  Balloon angioplasty of the tibial artery. (A) Femoral arteriography is performed. (B) The guidewire is advanced through a posterior tibial artery stenosis. (C) The angioplasty catheter is positioned across the lesion. (D) Balloon dilation of the posterior tibial artery is performed. (E) The balloon is removed and completion arteriography performed.

Tibial artery occlusive disease: Angioplasty and stenting  343

Balloons range from 1.5 to 4.5 mm in diameter. Longer low-profile balloons, up to 20 cm or even 30 cm in length, are available for the tibial arteries. The usual platform is 0.014-inch compatible and some prefer a 0.018-inch platform. An angled catheter is used to direct the guidewire into the tibial artery of choice. After the wire is across the lesion, it is best, if possible, to place a balloon that is long enough to cover the whole lesion with a single inflation (Figure 24.8). The balloon is inflated slowly until it reaches its full profile and inflation A

is maintained for a few minutes; 3 minutes is desirable. As the balloon expands and the constricting segments of the lesion give way, the pressure within the balloon typically decreases and this is reflected in the ­inflation manometer. It is common to underestimate the true diameter of the artery since the disease is typically in the medial layer of the artery and the overall caliber may not be apparent to the operator on angiography alone. Some hints of the true vessel caliber may be present by observation under plain fluoroscopy, as the

B

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Fig. 24.9  Tibial artery balloon angioplasty and stenting. (A) A sheath is placed just proximal to the lesion. (B) A directional catheter is used to help direct the guidewire into the appropriate tibial artery. (C) A low-profile angioplasty balloon that covers the length of the lesion is placed and inflated. (D) A significant postangioplasty dissection is present. (E) A stent is placed to treat the dissection.

344  The infrainguinal arteries: Advice about balloon angioplasty and stent placement

calcification in the vessel wall may be visible. After balloon withdrawal, completion arteriography is performed through the side arm of the sheath. If significant dissection or residual stenosis is present, repeat balloon inflation may be performed. If a stent is required in the proximal segment, near the tibial artery origin, a balloon-expandable stent is placed (Figure 24.9). This permits the greatest accuracy of placement. This is a location in the limb, between the tibia and fibula, that is relatively

protected from external forces. If stent placement is required in the remainder of the artery, a selfexpanding stent is used to accommodate the more flexible and mobile artery segments. There are no stents designed to work well at the ankle and foot. There are no stents approved for use in the tibial arteries in the USA. If a balloon-expandable stent is placed at the mid- or distal tibial level, a blood pressure cuff should not be inflated on the leg because of the risk of crushing the stent.

25 Complex lower extremity revascularization AORTOILIAC OCCLUSIVE DISEASE Recanalizing iliac artery occlusions There are several treatment options available for iliac artery occlusive disease. The previous gold standard of aortobifemoral bypass is rarely performed. Other open options include a variety of extra-anatomic bypasses, such as axillofemoral bypass and femoral–femoral bypass. A combination of extra-anatomic bypass and some endovascular inflow may also be performed. Previous treatment for unilateral iliac artery occlusion was frequently a femoral–femoral bypass. The vast majority of patients with aortoiliac occlusive disease can be treated with endovascular techniques, including most patients with TASC D lesions. Currently available tools permit recanalization of most iliac artery occlusions. Unilateral iliac artery occlusion is most common and there is often stenosis of the contralateral side. Bilateral iliac artery occlusions may also be treated using a bilateral endovascular approach. If one of the iliac arteries can be reopened and the other one cannot, stenting on one side can be performed followed by a ­femoral–femoral bypass. A variety of occlusions involving the aortoiliac segment are shown in Figure 25.1. Aortic occlusions that begin distally and extend into the iliac arteries can often be opened. Aortic occlusions that are flush with the renal arteries are more dangerous due to the risk of expressing compacted thrombus into the renal arteries or the visceral arteries. Likewise, for iliac artery occlusion, lesions that extend into the common femoral artery are more difficult and riskier to treat. In this case, the

iliac artery recanalization can be combined with a femoral endarterectomy. If that is not possible, the limb can be revascularized as the recipient of a femoral–femoral bypass.

Assessment of iliac artery occlusions When assessing iliac artery occlusions, it makes a difference as to whether these lesions are located in the common iliac artery alone or the external iliac artery alone, or whether they involve both the common and the external iliac arteries. In general, results are better with common iliac artery ­occlusions than with external iliac artery occlusions. The common iliac artery is a larger, shorter artery. Results with either common or external iliac artery occlusions are better than those in which both arteries are occluded on the same side. This is true for technical success and for long-term patency. A  patent internal iliac artery is helpful in recanalizing either a common iliac artery or an external iliac artery occlusion. The occlusion usually ends at the origin of the internal iliac artery. The internal iliac artery maintains flow in the p ­ atent segment juxtaposed to the occlusion. It can be used to anchor a wire. It can also be used to assist the operator in directing the wire in the ­correct direction to get across an iliac occlusion. With respect to common or external iliac artery occlusions, if the  proximal end or the distal end of the artery at  the lesion has a beak of patent vessel leading into the occlusion (as opposed to a flush occlusion), this will enhance getting into the occlusion (Figure 25.2). In the case of a common iliac artery occlusion, the beak or stump can be used to enter the occlusion, either by coming in 345

346  Complex lower extremity revascularization

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Fig. 25.1  Patterns of aortoiliac occlusive disease. These lesions are arranged in order from those that are simplest to treat with endovascular intervention to those that are the most complex. (A) Iliac ­stenosis is the most favorable situation for use of endovascular techniques. This is the index endovascular case. (B) Unilateral common iliac artery occlusion. These are more challenging when they present as a flush occlusion than when they have a beak or stump to help get into the lesion. (C) External iliac artery occlusion. This is a longer, smaller caliber artery than the common iliac artery. (D) Bilateral common iliac artery occlusion. (E) Combined common and external iliac artery occlusion. These can be quite challenging because the operator must enter the occlusion at the optimal location and reenter the true lumen at the optimal location, with minimal leeway for variation. (F) Combination of infrarenal aortic occlusion and bilateral common iliac artery occlusion. (G) Iliac occlusion combined with common femoral artery occlusion. (H) Iliac artery occlusion combined with extensive ­infrarenal aortic occlusion that extends from the level of the renal arteries. In general, the risk of technical ­failure and complications increases in managing occlusions that extend up toward the renal arteries or extend distally into the common femoral arteries.

Aortoiliac occlusive disease  347

A

B

Fig. 25.2  Approach to a common iliac artery occlusion. (A) A common iliac artery occlusion may be recanalized from a proximal approach, through a transbrachial or a transradial access. (B) The other option is an up-and-over approach from the contralateral femoral artery.

proximally from the brachial artery or by coming in over the aortic bifurcation from the contralateral side. If there is a flush occlusion of the proximal end of a common iliac artery occlusion, the benefit of approaching the lesion from a proximal access is higher. This is because the up-and-over approach is disadvantaged when approaching a flush occlusion. Getting the guidewire in the correct place with respect to the proximal end of a common iliac artery occlusion is often challenging when coming from below (Figure 25.3). The guidewire often will pass into the subadventitial space posterior to the aortic bifurcation. The distal aorta and proximal iliac arteries are often fused together in a continuous cast of calcific plaque. When the subadventitial guidewire comes in from below, it often will not be able to break through this calcium in order to pass back into the true lumen. Because of this, a higher likelihood of success usually results by approaching a common iliac artery occlusion from the proximal end, especially if there is a stump or beak of open artery that shows the way into the lesion. Nevertheless, approaching an iliac artery occlusion retrograde from the lower end of the occlusion is sometimes successful and often worth an attempt (Figure 25.4). When recanalizing common iliac artery occlusions, it may be necessary

Fig. 25.3  Passing a guidewire retrograde through a common iliac artery occlusion. It is usual for the guidewire to enter and progress through the lesion from a retrograde approach. However, after the wire enters the subintimal plane, it may be challenging to re-enter the true lumen proximally. This is a hit and miss ­process. This is especially the case when there is a ­substantial atherosclerotic disease burden of the aortic bifurcation or severe calcification of the infrarenal aorta. If you select this approach and the wire stays in the subintimal plane, set a time limit and move on to an alternative approach.

to approach the occlusion from both ends, using a bidirectional approach. In this case, it is important to make the wires meet along the length of the occlusion and not proximal or distal to it. If the subintimal planes meet proximal or distal to the occluded length, the reconstruction will be more lengthy and an important vessel may be impinged (contralateral common iliac artery proximally or internal iliac artery distally). An external iliac artery occlusion may have a beak of patent artery proximally or it may be a flush occlusion. Therefore, the principles that apply to common iliac artery occlusions also apply to the external iliac artery. External iliac artery occlusions usually extend to the junction with the common femoral artery, where the true lumen is reconstituted by the iliac circumflex vessels. The distal end of an external iliac artery occlusion

348  Complex lower extremity revascularization

A

B

D

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Fig. 25.4  Common iliac artery recanalization from the distal end. (A) A sheath is placed to provide a platform. (B) A braided, angle tip catheter is placed and a Glidewire® advanced through it to probe the lesion. (C) Using the catheter and the sheath for support, the guidewire is pushed into the most promising location and the wire buckles. Once the wire is anchored, the catheter is advanced into the lesion. (D) The guidewire loop progresses through the subintimal space and re-enters the true lumen. (E) The catheter is advanced over the guidewire to gain access to the true lumen.

is often a flush occlusion. It is usually suboptimal to approach an external iliac artery from its distal end because there is not enough working room from the ipsilateral common femoral artery. If a retrograde approach is absolutely necessary, consider accessing the superficial femoral artery (SFA) if it has an acceptable lumen. At the distal end of an external iliac artery occlusion, a smooth junction between the external iliac artery and the common femoral artery must be created when performing a reconstruction. This requires true lumen re-entry precisely at the junction of the external iliac and common femoral arteries. There is also a limitation to the use of stents at the reentry zone, because it is undesirable to place stents that extend too far into the common femoral artery. Re-entry into the common femoral artery distal to an external iliac artery occlusion can be facilitated by a re-entry catheter. This is discussed in more detail below.

The aortoiliac segment should be assessed based on preoperative imaging so that plans can be made ahead of time. These procedures may be time consuming and may involve different devices. If stent– graft relining of the occlusion is anticipated, this will affect the size of sheath selected. If there is the possibility of a combined open and endovascular approach (e.g., adding a femoral endarterectomy or femoral–femoral bypass), it will influence the choice of anesthesia and the sterile field preparation. Aortography or CTA may be used for preprocedure evaluation. Assess whether there is any hidden aneurysmal disease, which may have led to thrombosis of either a common or internal iliac artery, any significant tortuosity, or anything challenging about the aortic bifurcation (e.g., high placement, calcification). Usually, a preoperative study can assess whether the common femoral artery is going to be adequate. The length and caliber of the occluded artery can also be estimated.

Aortoiliac occlusive disease  349

Technique of iliac artery recanalization Needle access is usually obtained into the contralateral groin, assuming a unilateral occlusion. If there is bilateral occlusion, needle access is usually obtained at the brachial artery. If the common iliac artery is occluded but the external iliac and common femoral arteries are patent, needle access may be gained on either the contralateral or the ipsilateral side. A guidewire is advanced under fluoroscopic guidance and a 6-Fr sheath placed. Frequently, there is iliac artery occlusive disease, either stenosis or occlusion, that is contralateral to the iliac artery that requires treatment, and frequently guidewire passage will require some effort or extra steps. Once the guidewire is in the infrarenal aorta, a flush catheter is placed over the wire. The patient is given systemic anticoagulation with heparin. In the setting of extensive occlusive disease, flow in the aortoiliac segment may be slow and this observation should prompt more aggressive systemic anticoagulation during the procedure. An aortoiliac arteriogram is obtained with delayed filming so that reconstitution on the side of the occlusion can be imaged. Recanalizing an occlusion requires setting up an adequate treatment platform, which includes placement of a sheath. If the lesion is an external iliac artery occlusion or a common iliac artery occlusion that has a decent beak of artery at its origin, place a ­longer sheath (30–45 cm, 6-Fr) into the iliac artery. Be sure the sheath tip has a radiopaque marker. The A

B

sheath tip is advanced to the proximal common iliac artery. In the case of a common iliac artery occlusion, a hook-shaped or U-shaped catheter is placed through the sheath over the aortic bifurcation in the same way as you would to go over the aortic bifurcation for routine contralateral catheterization (Figure 25.5). The closer the occlusion initiates to the bifurcation, the more a stiff, hookshaped catheter is needed. Catheters to consider for this include a RIM catheter, a Sos Omni® catheter, an Amir Motarjeme® catheter, or any variety of hook-shaped visceral catheter. Once the catheter tip is engaged in the beak of a patent artery, a Glidewire® is advanced into the occluded artery. Sometimes, this is a relatively short distance and the guidewire tip will remain straight and resist going into the occlusion and will attempt to push the catheter out of the bifurcation every time forward pressure is placed on the wire. Sometimes, it forms a loop as it goes into the subintimal space. If the loop will not form in the subintimal space or it tries to push the catheter out with each application of forward pressure, there are other options. One is to use a catheter with a stiffer tip to support the wire better. Another option is to approach the occlusion from the brachial artery and push straight into the occlusion. Yet another option is to puncture the common femoral artery ipsilateral to the occlusion and pass the guidewire and catheter retrograde. Once the guidewire digs into the lesion, the catheter is advanced to anchor it into the lesion. Sometimes, it also helps to advance the sheath a ­little bit for maximum support (Figure 25.5). C

Fig. 25.5  Common iliac artery recanalization from the proximal end. (A) A sheath is placed so that its tip is in the proximal common iliac artery. (B) A hook-shaped catheter is placed so that the tip of the catheter is pointing inferiorly and directly into the occlusion. (C) A wire is gently advanced, so that it does not kick the catheter out of position. The wire forms a loop and is advanced.

350  Complex lower extremity revascularization

After the loop forms and there are several to many centimeters of guidewire and catheter on the contralateral side, a 6-Fr sheath can frequently be advanced over the aortic bifurcation directly over the guidewire and catheter combination. This step helps to provide additional support for pushability in the direction of the occlusion. The loop of Glidewire® is advanced and often it will pop back into the true lumen distal to the occlusion. Another option, other than a looped subintimal hydrophilic guidewire, is to use a low-profile 0.018inch or 0.014-inch compatible, stiff tip exchange catheter (Quick-Cross™ Support catheter). This is a microcatheter with a stiff tip that can be passed directly through a 5-Fr angiographic catheter and, combined with a stiff, low-profile guidewire, frequently is enough to push across an occlusion. When treating a common iliac artery occlusion, it may be of value to perform an ipsilateral retrograde approach, especially if there is no success coming from the proximal end or some reason why this approach should be avoided. Just remember that when an artery access site is created distal to an occlusion, if the reconstruction is not successful and pressure at the access site remains low, the opportunity for puncture site thrombosis to occur is increased. Ipsilateral retrograde access can be performed using a micropuncture needle under fluoroscopic guidance. The micropuncture needle can be entered into the artery in several ways. Sometimes with a common iliac artery occlusion, there is still a palpable pulse as pulsatile blood flows through internal iliac artery collaterals. Also, injecting contrast into the aorta from some other route will reconstitute femoral artery and this can be road mapped. The road mapped image can be used to puncture with the micropuncture needle. Ultrasound-guided puncture is helpful and is the preferred method. The artery may be quite small in diameter due to hypoperfusion. In the case of a common iliac artery occlusion with a patent external iliac artery, there is enough artery for an acceptable length of guidewire to be passed retrograde so that a sheath can be placed from the groin area. This will allow placement of a short 6-Fr sheath. A 6-Fr sheath with a radiopaque tip should be used so that the tip of the sheath can be advanced directly up to just below the occlusion. Most reconstructive options are available through a 6-Fr sheath. From this position, a couple of different angles are obtained to help see where

the best place is to approach the lesion. There are various options for approaching the lesion and these include passage of a Glidewire® and possibly forming a loop and a subintimal angioplasty, as described earlier. Another option is to use a QuickCross™ Support catheter directly from below. This type of catheter is used with a stiff guidewire. The catheter and guidewire are advanced in a stepby-step manner, one and then the other, until the occlusion is crossed. If this is not successful, a reentry catheter may be advanced over the guidewire through the 6-Fr sheath and a re-entry needle can be placed just proximal to the origin of the occlusion. If the occlusion is near the origin of the common iliac artery or flush at the origin, with the bifurcation of the aorta being partly obscured, a kissing stent should be placed on the contralateral side so that any debris or compacted thrombus located at the bifurcation may be caged at this point and not forced into the patent contralateral side (Figure  25.6). A common iliac artery occlusion that originates within a few millimeters of the bifurcation requires bilateral access and will probably also require kissing stents to reconstruct. If the occlusion involves the infrarenal aorta to some degree and the iliac arteries, then an aortic stent can be placed first followed by kissing bilateral iliac stents. External iliac artery occlusions have some nuances that make them different from common iliac artery occlusions. They are almost always approached in an up-and-over manner because of the challenge of getting working room when the ipsilateral side is punctured, as mentioned earlier. The challenge with an external iliac artery occlusion is getting back in at the appointed location at the junction between the external iliac and common femoral arteries. The patient is fully anticoagulated. The guidewire and catheter system is advanced into the internal iliac artery. In order to get enough of an anchor to pass the sheath over the aortic bifurcation, the stiff exchange wire is passed as far as possible into the internal iliac artery. A  6-Fr or 7-Fr sheath is passed over the aortic bifurcation on a stiff guidewire, and the sheath tip can even be advanced all the way into the internal iliac artery to get as close to the origin of the occlusion as possible. The stiff guidewire is removed and an angle tip catheter is placed into the 6-Fr or 7-Fr sheath. The sheath is then withdrawn just a little

Aortoiliac occlusive disease  351

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Fig. 25.6  Kissing stents of the aortic bifurcation. (A) Bilateral guidewires and balloon catheters are placed. Because the right side has a significant lesion and because it is also very near the bifurcation, both arteries are accessed. (B) Kissing balloon angioplasty is performed. The balloon in the left iliac artery is used to “protect” the artery. (C) There is a substantial residual s­ tenosis on the right side and the intended stent will be required to raise the bifurcation to treat the lesion. (D) Kissing stents are placed to raise the aortic bifurcation.

bit and readjusted until a slight movement can be seen at the tip of the sheath, which indicates that it has popped from the internal iliac artery and back into the distal common iliac artery. A couple of different angiographic angles are obtained by injecting contrast through either the catheter or the sheath, with the catheter pointing directly down the barrel of the external iliac artery. A contralateral anterior oblique view is usually best for visualizing the common iliac artery bifurcation and understanding where the proximal external iliac artery is located. At this point, one has a choice

of either using a Glidewire® and forming a loop and going subintimal through the external iliac artery, or using a combination of a microcatheter and a 0.014-inch or 0.018-inch diameter guidewire. Whichever method is chosen to cross the occlusion, the goal is to have the wire break back into the true lumen on its own. If there is challenge in re-entering, this is a good position for placement of a re-entry catheter and using the needle on the catheter to enter the true lumen. The location of the sheath is also perfect because injecting through the side arm of the sheath will allow reconstitution of contrast into the location where re-entry is desired. Re-entry can also be performed with a re-entry catheter, most commonly an Outback® catheter or a Pioneer Plus catheter. Both catheters are relatively stiff. Therefore, if being considered for use in an up-and-over approach, a 7-Fr sheath is desirable. A re-entry catheter can also be used when passed retrograde from the ipsilateral common femoral artery and into a common iliac artery occlusion. This will aid in re-entry into the true lumen in the distal aorta. In this setting, consider using an intravenous ultrasound (IVUS)-guided catheter (Pioneer Plus) to be certain that the wire is directed in the appropriate direction. There are no significant turns to be made and the puncturing needle is directed into the location closest to where the common iliac artery origin is located. Using IVUS to re-enter proximal to the common iliac artery occlusion is also helpful to re-enter away from the patent contralateral iliac artery. After the occlusion has been traversed, whether it is in the common iliac artery or the external iliac artery, or both, the operator has a choice of how to reconstruct the lesion. In general, after recanalizing iliac artery occlusions, most experts advise stenting the lesion or placing stent–grafts. In the external iliac artery, the entire occluded segment should be stented using self-expanding stents. Accurate stent placement is required on the distal end of the occlusion because stent placement too far into the common femoral artery should be avoided. This is facilitated by an over-the-bifurcation approach, because the self-expanding stents are deployed from the tip end to the hub end. In the common iliac artery, there is a broader choice of self-expanding or balloon-expandable stents. If the aortic bifurcation is heavily calcified and/or there is a lot of distal aortic disease, balloon-expandable

352  Complex lower extremity revascularization

stents are used. Self-expanding stents are a reasonable choice for longer occlusions or in arteries that are somewhat tortuous, especially if there is less aortic disease. If the stents extend into  the aorta, they must be placed carefully so that they are equal on the bilateral sides. If there is a fair degree of disease in the distal aorta and/or the aortic bifurcation must be raised a bit, self-expanding stents do not work as well. It is not uncommon to stent across the origin of the internal iliac artery with bare metal stents. This usually does not negatively affect the patency of the internal iliac artery. A covered stent across the internal iliac artery would necessarily exclude it from the circulation and is generally avoided. The biggest challenges with iliac artery recanalization are: ●●

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Where you have got through an external iliac artery occlusion but are unable to enter at the appropriate location at the external iliac common femoral artery junction. When disease extends from an occluded external iliac artery directly into a heavily calcified and possibly even occluded common femoral artery. These are difficult to treat from an endovascular standpoint, if not impossible. When there is a combined occlusion of both the common iliac artery and the external iliac artery. These are challenging to cross and often require some innovative steps to do so. Recanalizing a common iliac artery but then finding the distal aorta is so calcified that it is impossible to break through to get back into the true lumen. When performing iliac artery recanalization, the worst scenario other than rupture (which is rare) is distal embolization. This is one reason why it is appropriate to cover the whole occlusion, if possible.

Some operators like to use covered stents or stent–grafts to cover the occlusion. There is some evidence to suggest that the long-term patency is improved by using covered stents for iliac artery reconstruction. If a stent–graft is selected, some of the features that must be considered include: ●●

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A larger sheath may be required depending on the finished desired diameter of the stent–graft. It is likely that there will be some predilation required because the stent–graft, no matter

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how tightly it is packed on its delivery catheter, is high profile and has some rough edges, which may catch on the lesion and may not want to pass. Perfect placement is usually required because one would not want to cover the collaterals at the medial and lateral iliac circumflex, cover the internal iliac artery, or extend one end of the stent–graft up into the aortic bifurcation unless it was met on the contralateral side with an opposing structure, such as a contralateral kissing stent–graft.

Managing aortic occlusion As mentioned earlier, if an infrarenal aortic occlusion extends to the renal arteries, the risks of revascularization are increased due to the potential that debris from the disrupted occlusion can embolize into the visceral or renal arteries. In this setting, some other type of revascularization should be considered. If it is clear that endovascular recanalization and reconstruction is best, consider the following approach. Use extra anticoagulation so that thrombus will not propagate in areas of no flow or slow flow. If wire passage can be achieved across the aortic occlusion, consider using IVUS to ensure that the wire is in the true lumen at the location where the reconstitution is at the level of the renal arteries. With either no predilation or minimal predilation, just enough to pass the stent–graft, consider relining the entire occluded segment using a self-expanding endovascular graft similar to what would be used for aortic aneurysm treatment. This can be done using either a stack of cuffs or a series of large diameter extension limbs. In this manner, the accumulated thrombus should be excluded. When the reconstruction is finished, be sure that there is no evidence of thrombus formation in the visceral and renal arteries. If the aortic occlusion initiates in the middle or distal infrarenal aorta and there is runoff into some of the lumbar arteries, the risks are much less. In this setting, a large diameter self-expanding bare metal stent or covered stent could be used. Note that in this situation, the inferior mesenteric artery is frequently patent and it may be desirable to avoid a covered stent over this area. If the iliac arteries are also involved, the infrarenal stent is placed first and then bilateral wires, and bilateral iliac stents are placed to complete the reconstruction.

Femoral–popliteal occlusive disease  353

When the iliac arteries are also diseased and are included in the planned reconstruction, the wire must be placed across each one before deciding on the reconstruction. If one of the iliac arteries cannot be crossed, the reconstruction will be performed differently. For example, a stent may be placed to extend from the aortic bifurcation into one iliac artery and then a femoral–femoral bypass performed. MANAGING HIGHLY CALCIFIED LESIONS

There are several issues with highly calcified lesions that should be considered and some maneuvers that can help work one’s way around them. Highly calcified lesions pose the risk that the calcium will not give way and the lesion can be pushed through the arterial wall if dilated too aggressively and all at once, causing potentially a localized or free rupture. The other risk is that the lesion may be recalcitrant to dilation and it may not be possible to gain an adequate lumen. In order to avoid this scenario, the lesion could be gradually dilated to ensure that a lumen is created. Cutting or scoring balloons can also be used in this situation. If a patient is experiencing severe pain with dilation, it usually makes sense to permit some degree of residual stenosis rather than attempting to achieve a perfect cosmetic result. When it is likely that a residual stenosis will be present, it is often not possible for a balloon-expandable stent to oppose the wall both proximal and distal to the location of the lesion. In this setting, a self-expanding stent with continued gradual and stepwise poststent dilation at the location of residual stenosis could be used. ACCESS SITE MANAGEMENT WHEN TREATING AORTOILIAC OCCLUSION

Frequently, when dealing with aortoiliac occlusion, there is an access site ipsilateral to and distal to the reconstruction. In this case, closure devices have the advantage of continued flow beyond the access site immediately after performing closure. This helps to prevent access site thrombosis. However, if the artery is quite small (7-Fr). Closure devices can be used while the patient is still anticoagulated, without waiting until a later time to manage the sheath. As experience has increased over time, closure devices have become more widely used and most operators have developed a workflow that takes these devices into account. Increasing experience levels and better patient selection have also helped to decrease complication rates. Challenges with closure devices include cost, occasional acute failure to close the arteriotomy, and rare but devastating complications such as local infection or distal embolization. Closure devices are only approved for femoral access. The instructions for use should be followed when selecting patients in which to use these devices. The main reason not to use a closure device is because of some technical or anatomic issue that precludes its use. A severely diseased, calcified, or stenotic femoral artery is the most common ­reason. If the puncture site is low, at the femoral bifurcation, or in the profunda femoris or superficial femoral artery (SFA), it is usually better to hold the access site manually than to use a closure device. When a treatment site, such as the distal end of an ­external iliac artery stent, is close to the puncture site, there is a risk that the device will catch on the stent. Much of this can be obviated by using ultrasound guidance to choose a puncture site and to guide the needle insertion into the location that is most favorable for closure. There are two general categories of closure devices: those that place a stitch (e.g., Perclose ProGlide™, Figure 30.3) or rivet (e.g., Prostar®, Figure 30.4) and those that place a collagen plug (e.g., Angio-seal or Exo-seal, Figures 30.5 and 30.6).

430  Puncture site management

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Fig. 30.3  Suture-mediated closure device. (A) The Perclose ProGlide™ is featured in Chapter 28, Figure 28.1, in the section on large vessel closure. A side view of an artery requiring closure is demonstrated. (B) The closure device is advanced until the guidewire port reaches the skin level and the wire is then removed. (C) The closure device catheter is advanced until there is backbleeding from the side port. This indicates that the sutures are at the level of the artery. (D) The lever on the side is pushed upward to deploy the foot plates. (E) The plunger is depressed to deploy the sutures. (F) The lever is released to gather up the foot plates and the closure catheter is removed. (G) On removal of the catheter the knot pusher is used to push the knot to the artery along the blue-tipped suture, which remains under tension, and subsequently the white-tipped suture is also placed on tension to set the knot.

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Fig. 30.4  Clip on the outside of the vessel. (A) The closure device is inserted into the artery. It is adjusted so that the tip is just inside the vessel. (B) The clip is placed, gathering up adventitia on the outside of the vessel. (C) The closure device is removed and pressure held for a few minutes.

Closure devices  431

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Fig. 30.5  Collagen plug-mediated closure device. (A) The sheath is advanced until the tip of the sheath is inside the artery and backbleeding is seen through a side port. (B) The collagen plug is loaded into the sheath and pushed to its tip. (C) After the disc is inside the artery, the sheath is removed. By putting traction on the sheath, the collagen plug is brought down to the artery. After the collagen plug is in place and tension held for a few seconds, the suture may be divided below the skin level.

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Fig. 30.6  Collagen plug on the outside of the vessel. (A) The sheath is advanced until backbleeding is achieved. (B) A small balloon is inflated to fill the space and prevent backbleeding from the artery. (C) A collagen plug is placed and allowed to form. (D) The balloon is deflated and removed and pressure is held for a few minutes.

There are more examples of each of these types of closure devices than those mentioned here. Both of the types described here have been widely adopted and have acceptably low complication rates. Most accomplished operators are experienced with and regularly use at least one and sometimes two devices in each of these categories. Common to the use of all closure devices is the advantage of ultrasound guidance and the need for a very meticulously kept sterile technique. Each type of device has its nuances and each is being continually refined. Suture-mediated closure is warranted for large bore access closure. This includes sheath access >10-Fr. At 12-Fr, two

suture-mediated closure catheters are used, as described in Chapter 28. The skin incision must be enlarged a little if a smaller caliber sheath is used (i.e., 6-Fr or less). The reason for this is to have a clear and open path for the knot to be delivered to the anterior wall of the artery. The sutures are monofilament and they must be wet to slide on themselves. Traction  on the secondary suture prematurely (with the white tip) will set the knot being delivered and hemostasis will be poor. Suture-mediated closure requires the catheter to be advanced without guidewire guidance for a portion of its insertion. Most of the time, this is not consequential. However, if the patient

432  Puncture site management

has undergone an iliac artery reconstruction or the arteries are diseased or severely tortuous, this maneuver may not be possible. In severely calcified arteries the needle that delivers the suture may not penetrate the artery. After the guidewire is removed, any breakage of the suture or other failure means that closure is not possible, except by manual pressure or open repair. In patients with a hostile common femoral artery and a reasonably large diameter proximal SFA, the proximal SFA may be considered for access, although this is not a labeled usage for the device. Placement of a suture-mediated closure device too far proximally along the common femoral artery may result in the device going through the inguinal ligament. This is typically painful and may cause the device to fail when the patient gets up to ambulate. Collagen plug-mediated closure devices deliver a collagen plug to the anterior surface of the artery. The collagen plug may fill the entire tract from the skin puncture to the artery to varying degrees. Collagen is more susceptible to the possibility of infection. The collagen plug may be delivered as part of a sandwich, with a small disc on the inside of the artery anchored to a small plug on the outside of the artery. The collagen plug may also be delivered only to the outside of the artery and expand to fill a large portion of the tract and help to secure its position in that manner. Ultrasound guidance is useful in placing the needle puncture at the least diseased location and on the anterior surface of the common femoral artery. A collagen

plug may fail if the artery is punctured on its side. A collagen puncture may also fail if it is placed through the inguinal ligament. When the patient ambulates, the plug will likely move and cause sudden hemorrhage. Collagen plugs are useful for sheaths up to about 8-Fr. Larger arteriotomies are not as securely managed using this technique. A major challenge occurs when the puncture is located near an occlusive lesion in the common femoral artery. This is typically identified using an oblique femoral arteriogram. Proceeding with closure is typically outside the instructions for use.

MANAGING PUNCTURE SITE COMPLICATIONS Several factors contribute to percutaneous femoral artery puncture site hemorrhage: anticoagulation or bleeding disorders; presence of severe common femoral artery calcification; high puncture, involving the distal external iliac artery; low puncture, involving the crotch of the femoral bifurcation or proximal deep femoral artery; a puncture site that lacerates the side of the artery; or a large caliber arteriotomy (especially 10-Fr or larger). Puncture site management is often relegated to a member of the team with the least experience or understanding of the procedure performed. However, managing a complication after it has occurred requires more energy and expertise than is needed when the puncture site is managed well to begin with.

Selected reading

PART I AbuRahma AF, Elmore M, Deel J et al. (2007) Complications of diagnostic arteriography performed by a vascular surgeon in a recent series of 558 patients. Vascular 15(2):92–7. Fujihara M, Haramitsu Y, Ohshimo K et al. (2017) Appropriate hemostasis by routine use of ultrasound echo-guided transfemoral access and vascular closure devices after lower extremity percutaneous revascularization. Cardiovasc Interv Ther 32(3):233–40. Geschwind J (2013) Abram’s Angiography. Lippincott, Williams & Wilkins, Philadelphia. Jahnke T, Schäfer JP, Bolte H et al. (2008) Retrospective study of rapid-exchange monorail versus over-the-wire technique for femoropopliteal angioplasty. Cardiovasc Intervent Radiol 31(5):854–9. Kim D (2017) Vascular Imaging and Endovascular Interventions. Jaypee Brothers Medical Publishers, London. Lonn L, Edmond JJ, Marco J, Kearney PP, Gallagher AG (2012) Virtual reality simulation training in a high–fidelity procedure suite: operator appraisal. J Vasc Interv Radiol 23(10):1361–6. Madden NJ, Calligaro KD, Zheng H et al. (2019) Outcomes of brachial artery access for endovascular interventions. Ann Vasc Surg 56:81–6. Montero-Baker M, Schmidt A, Bräunlich S et al. (2008) Retrograde approach for complex popliteal and tibioperoneal occlusions. J Endovasc Ther 15(5):594–604. Osborn AG (1999) Diagnostic Cerebral Angiography. Wolters Kluwer Health, Philadelphia.

Schroeder J (2013) Peripheral Vascular Interventions: An Illustrated Manual. Thieme, Stuttgart. Seldinger S (1953) Catheter replacement of the needle in percutaneous arteriography. Acta Radiol 39:368–76. Sobolev M, Slovut DP, Lee Chang A et al. (2015) Ultrasound-guided catheterization of the femoral artery: A systematic review and meta-analysis of randomized controlled trials. J Invasive Cardiol 27(7):318–23. Vatakencherry G, Gandhi R, Molloy C (2016) Endovascular access for challenging anatomies in peripheral vascular interventions. Tech Vasc Interv Radiol 19(2):113–22. Walker C (2013) Guidewire selection for peripheral vascular interventions: Understanding the design elements of interventional guidewires is the basis for successful use. Endovascular Today May 2013. Zia S, Singh K, Juneja A et al. (2018) Safety and feasibility of transradial access for noncoronary and peripheral vascular interventions. Ann Vasc Surg 53:255–61.

PART II Banerjee S, Thomas R, Sarode K et al. (2014) Crossing of infrainguinal peripheral arterial chronic total occlusion with a blunt microdissection catheter. J Invasive Cardiol 26(8):363–9. Bausback Y, Wittig T, Schmidt A et al. (2019) Drug-eluting stent versus drug-coated balloon revascularization in patients with femoropopliteal arterial disease. J Am Coll Cardiol 73(6):667–79.

433

434   Selected reading

Bosiers M, Deloose K, Verbist J et al. (2008) Present and future of endovascular SFA treatment: Stents, stent-grafts, drug coated balloons and drug coated stents. J Cardiovasc Surg (Torino) 49(2):159–65. Dietrich EB (1996) Endovascular suite design. In: Peripheral Endovascular Interventions. (eds RA White, TJ Fogarty TJ) Mosby, St. Louis, pp. 129–39. Dotter CT (1969) Transluminally placed coilspring endarterial tube grafts: Long-term patency in canine popliteal artery. Invest Radiol 4:327–32. He R, Ye Y, Li Z (2019) Restenosis prevention with drug eluting or covered stents in femoropopliteal arterial occlusive disease: Evidence from a comprehensive network meta-analysis. Eur J Vasc Endovasc Surg 58(1):61–74. Igari K, Kudo T, Toyofuku T (2015) Controlled antegrade and retrograde subintimal tracking technique for endovascular treatment of the superficial femoral artery with chronic total occlusion. Ann Vasc Surg 29(6):1320. e7–1320.e10. Iida O, Urasawa K, Komura Y et al. (2019) Selfexpanding nitinol stent vs percutaneous transluminal angioplasty in the treatment of femoropopliteal lesions: 3-Year data from the SM–01 trial. J Endovasc Ther 26(2):158–67. Joh JH (2019) Endovascular intervention with a mobile C-arm in the operating room. Vasc Specialist Int 35(2):70–6. Kerlan RK (2000) Angioplasty. In: Interventional Radiology Essentials. (eds JM LaBerge, RL Gordon, RK Kerlan, MW Wilson). Lippincott Williams & Wilkins, Philadelphia, pp. 147–64. Silva MB, Haser PB, Coogan SM (2001) Guidewires, catheters and sheaths. In: Endovascular Surgery. (eds WS Moore, SS Ahn SS) WB Saunders, Philadelphia, pp. 48–53. Uflacker R (2002) Angioplasty procedures. In: Endovascular Therapy. (ed R Uflacker) Lippincott Williams & Wilkins, Philadelphia, pp. 1–60. Zeller T, Peeters P, Bosiers M et al. (2014) Heparin-bonded stent-graft for the treatment of TASC II C and D femoropopliteal lesions: The Viabahn-25 cm trial. J Endovasc Ther 21(6):765–74.

PART III Deloose K, Martins I, Neves C et al. (2019) Endovascular treatment for the common femoral artery: is there a challenger to open surgery? J Cardiovasc Surg (Torino) 60(1):8–13. Kaki A, Blank N, Alraies MC et al. (2018) Access and closure management of large bore femoral arterial access. J Interv Cardiol 31(6):969–77. Kokkinidis DG, Foley TR, Cotter R et al. (2019) Acute and midterm outcomes of antegrade vs retrograde crossing strategies for endovascular treatment of iliac artery chronic total occlusions. J Endovasc Ther 26(3):342–49. Malas MB, Leal J, Kashyap V et al. (2017) Technical aspects of transcarotid artery revascularization using the ENROUTE transcarotid neuroprotection and stent system. J Vasc Surg 65(3):916–20. Mirza AK, Oderich GS, Sandri GA et al. (2019) Outcomes of upper extremity access during fenestrated–branched endovascular aortic repair. J Vasc Surg 9(3):635–43. Oderich GS (2017) Endovascular Aortic Repair: Current Techniques with Fenestrated, Branched and Parallel Stent-Grafts. Springer Verlag, Berlin. Orrico M, Ronchey S, Setacci C et al. (2019) The “Destino–guided BEVAR” to catheterize downward branches from a femoral access: Technical note and case report. Ann Vasc Surg 57:266–71. Osborn AG (1999) Diagnostic Cerebral Angiography. Wolters Kluwer Health, Philadelphia. PV Podium Crossing techniques for peripheral vascular interventions. www.pvpodium. com/content/pvpodium/en-us/clinical-skills/­ crossing.html. Rowse JW, Morrow K, Bena JF et al. (2018) Iliac conduits remain safe in complex endovascular aortic repair. J Vasc Surg Dec 28. pii: S0741–5214(18)32561–8. Schaefer PJ, Schaefer FK, Hinrichsen H et al. (2006) Stent placement with the monorail technique for treatment of mesenteric artery stenosis. J Vasc Interv Radiol 17(4):637–43.

Selected reading  435

Schmidt A, Bakker OJ, Bausback Y et al. (2017) The tibiopedal retrograde vascular access for challenging popliteal and below-the-knee chronic total occlusions: Literature review and description of the technique. J Cardiovasc Surg (Torino) 58(3):371–82. Shah SM, Bortnick A, Bertrand OF et al. (2019) Transpedal vs. femoral access for peripheral arterial interventions - A single center experience. Catheter Cardiovasc Interv 93(7):1311–14.

Tatiana B, Peter K, Peter K et al. (2019) Aortic stenting in symptomatic infrarenal aortic stenosis and subtotal aortic occlusion. Vasc Endovascular Surg 53(4):303–9. Vance AZ, Leung DA, Clark TW (2018) Tips for pedal access: Technical evolution and review. J Cardiovasc Surg (Torino) 59(5):685–91. van Wiechen MP, Ligthart JM, Van Mieghem NM (2019) Large-bore vascular closure: New devices and techniques. Interv Cardiol 14(1):17–21.

Appendix: Trade/registered/generic names plus current manufacturers

ACCESS SET Micropuncture® Access Set (Cook Medical)

GUIDEWIRES Amplatz Support Wire Guide (Cook Medical) Amplatz Super Stiff ™ Guidewire (Boston Scientific) Asahi Grand Slam Guidewire (Vascular Perspectives) Bentson Wire Guide (Cook Medical) Command® Guidewire (Abbott Vascular) Glidewire® Advantage Guidewire (Terumo Medical) Lunderquist® Extra-Stiff Wire Guide (Cook Medical) Magic Torque™ Guidewire (Boston Scientific) Newton Wire Guide (Merit Medical Systems; Cook Medical) Roadrunner® Guidewire (Cook Medical; Cordis) Rosen Wire Guide (Cook Medical) Rosen Starter ™ Guidewire (Boston Scientific) Starter® Guidewire (Boston Scientific) Supra Core® Guidewire (Abbott Vascular) TAD Guidewire (Boston Scientific; Abbott Vascular) V-18™ ControlWire™ Guidewire (Boston Scientific)

CATHETERS Amir Motarjeme® Catheter (Merit Medical Systems) Berenstein Catheter (Boston Scientific) C2 Cobra Catheter (Cook Medical) Chuang A, B, D, and E Catheters (Cook Medical) Crosser® CTO Recanalization Catheter (Bard Peripheral Vascular) CXI® Support Catheter (Cook Medical) DAV Catheter (Beacon+ Tip 5.0 Fr) (Cook Medical) Dorado® PTA Dilatation Catheters (Cook Medical) Export® AP Aspiration Catheter (Medtronic) Frontrunner® XP CTO Catheter (Cordis) Glidecath® (Boston Scientific) 437

438   Appendix: Trade/registered/generic names plus current manufacturers

H3 and H1 Headhunter Catheters (Merit Medical Systems; Cook Medical; Boston Scientific) Hook 1 and 2 Catheters (Angiodynamics) JB1 and JB2 Catheters (Angiodynamics; Cook Medical; Boston Scientific) J-Guidewire (Cook Medical; Cordis) Kumpe Catheter (Cook Medical) Multipurpose A (MPA) and B (MPB) Catheters (Cordis; Cook Medical) Omni® Flush Catheter (Angiodynamics) Pigtail Catheter (several companies) Pronto® LP Extraction Catheter (Vascular Solutions) Prowler® Select® Microcatheter (Cordis) Quick-Cross™ Support Catheter (Spectranetics) Renal Double Curve Catheter (Merit Medical Systems) Renegade™ Microcatheter (Boston Scientific) RIM Catheter (Merit Medical Systems) Rosch IMA Catheter (Cook Medical) Shepherd Hook Catheter (Merit Medical Systems) Simmons 1, 2, and 3 Catheters (Merit Medical Systems; Cook Medical; Boston Scientific; and others) Sos Omni® 2 Catheter (Angiodynamics) Vert Catheter (Cook Medical) TegT Catheter (Beacon® Tip 5.0 Fr) (Cook Medical) Tennis Racquet Catheter (Boston Scientific) Vitek Catheter (Cook Medical)

SHEATHS Destination® Peripheral Guiding Sheath (Terumo Medical) Destination® Angled Sheath (Terumo Medical) Destino™ Sheath (Articulating sheath tip) (Oscor Inc.) Flexor® Raabe Guiding Sheath (Cook Medical) Flexor® Shuttle® Guiding Sheath (Cook Medical)

STENTS/GRAFTS Fluency® Plus Endovascular Stent Graft (Bard Peripheral Vascular) Gore® Viabahn® VBX Balloon Expandable Stent Graft (Gore Medical) iCast™ Balloon Expandable Covered Stent (Atrium Medical) Lifestream® Balloon Expandable Covered Stent (Bard Peripheral Vascular) Palmaz™ Stent (Cordis) Supera® Stent (Abbott Vascular) Wallgraft ™ Endoprosthesis (Boston Scientific) Wallstent® Stent (Boston Scientific) Zilver® PTX® Drug-Eluting Peripheral Stent (Cook Medical)

CLOSURE DEVICES Amplatz™ Vessel Occluders (Abbott Vascular) Angio-seal™ VIP (or Evolution) Vascular Closure Device (Terumo Medical) EXOSEAL ® Vascular Closure Device (Cordis) Mynx® Vascular Closure Device (Cardinal Health) Perclose ProGlide™ Suture-mediated Closure System (Abbott Vascular)

Appendix: Trade/registered/generic names plus current manufacturers  439

PROTECTION DEVICES AngioGuard® RX Guidewire System (Cordis) Emboshield NAV6™ Embolic Protection System (Abbott Vascular) FilterWire EZ™ Embolic Protection System (Boston Scientific) Mo.Ma™ Ultra Proximal Cerebral Protection Device (Medtronic) PercuSurge Guardwire™ (Medtronic) RX Accunet™ Embolic Protection System (Abbott Vascular) SpiderFX Embolic Protection Device (Medtronic)

MISCELLANEOUS AngioJet™ Peripheral Thrombectomy System (Boston Scientific) CVX-300 ® Excimer Laser System (Spectranetics) Outback® Re-entry Catheter (Cordis) Penumbra Aspiration Device (Penumbra Inc.) Pioneer Plus IVUS-guided Re-entry Catheter (Royal Philips) Prostar® XL Percutaneous Vascular Surgical System (Abbott Vascular) SilverHawk Peripheral Plaque Excision System (Medtronic)

COMPANY ADDRESSES Abbott Vascular, Abbott Park, Illinois, USA Angiodynamics, Queensbury, New York, USA Atrium Medical, Hudson, New Hampshire, USA Bard Peripheral Vascular, Tempe, Arizona, USA Boston Scientific, Natick, Massachusetts, USA Cardinal Health, Dublin, Ohio, USA Cook Medical, Bloomington, Indiana, USA Cordis, Miami, Florida, USA Gore Medical, Flagstaff, Arizona, USA Medtronic, Minneapolis, Minnesota, USA Merit Medical Systems, Salt Lake City, Utah, USA Oscor Inc., Palm Harbor, Florida, USA Penumbra Inc., Alameda, California, USA Royal Philips, Amsterdam, The Netherlands Spectranetics, Colorado Springs, Colorado, USA Terumo Medical, Somerset, New Jersey, USA Vascular Perspectives, Huddersfield, UK Vascular Solutions, Minneapolis, Minnesota, USA

Index

abandoning an access 21, 33–4 abdominal pannus management 18, 19 aberrant anatomy 111–12 access 8–9 alternative access to the lower extremity 23 for aortoiliac interventions 353 brachial artery puncture 21–3 bypass grafts 23–4 comparison of puncture site options 24–5 dilators 28, 29, 30–2 for endovascular therapy aortic aneurysms 391–2 avoiding using the initial access site for therapy 155 guiding sheaths versus guiding catheters 155–6 hybrid procedures 384–6 planning 150 sheath placement 153–5, 156–60 simple rules 149–50 sizing issues 150–3 up-and-over approach 105–6, 157, 158, 329–30, 337–41 upper extremity 158–9 femoral artery anatomy 9–10 antegrade puncture 17–19 fluoroscopic guidance 20 hostile groins 34 pulseless artery 19–20 retrograde puncture 13–16 forehand approach 9 guidewire advancement problems 16–17 micropuncture technique 12

principles 7 proximal access 21 securing access 28 sheath placement 28–31 single- and double-wall puncture techniques 14 sizing issues 32 ultrasound guidance 10–12 see also puncture site choice access sheaths 152 sizing issues 151 activated clotting time (ACT) 145–6, 197 acute occlusion management 219 allergies 115 contrast agents 147 heparin 146, 148 protamine reactions 146 analgesia 145 anaphylactic reactions, patient history of 147 anatomic manipulations 188–9 aneurysms arteriography 114, 136–7 coil embolization 419–21 internal iliac artery 422–3 technique 421–2 guidewire–catheter skills 72–3 juxtaposition with occlusive lesions 133 popliteal 424–5 short-neck 134 vessel occluders 423–4 see also aortic aneurysms angiographic catheters 53–4, 63 angiosomes of the foot 367 antegrade femoral puncture 17–19, 24–5, 116

anterior tibial artery, area served by 367 antibiotic prophylaxis 145 anticoagulation 4, 145–6 prior to arteriography 115 antiplatelet therapy 4, 146–7 prior to carotid bifurcation stenting 281 aortic aneurysms, duplex scanning 137 aortic aneurysm repair 401 bad iliac arteries 394 access diameter issues 396–7 calcification 396 diseased arteries 397, 398 tortuosity 397–8, 399 balloon angioplasty after graft placement 405 cannulation of the contralateral gate 403, 405, 406 conduits 398–401 difficult aortic neck 407–11 endograft placement 401–3 endoleak management 414–17 hybrid procedures 413–14 iliac stent placement 406–7 imaging 391–2 open femoral access 392 percutaneous access 392 large bore closure 394, 395 large bore using pre-close technique 392–4 ruptured aneurysms 411–13 aortic angioplasty 220 balloon catheter length 195 balloon sizing 194 pain 210 aortic arch, aberrant anatomy 111, 112 441

442   Index

aortic arch aortography 91, 93–4, 121, 123, 134, 276–7 catheter placement 118–19 aortic arch assessment 275, 277 aortic arch branches assessment 276–7 selective catheterization 93–8 aortic arch debranching 413–14 aortic bifurcation, passage over 100–5 aortic bifurcation angioplasty 313–14, 318–19 balloon sizing 194 aortic bifurcation stents 238, 241, 242, 319–20 aortic dissection guidewire–catheter skills 74–5 intravascular ultrasound 137 aortic occlusions 179, 181, 182 management 352–3 aortic procedures choice of platform 50 see also infrarenal aortic interventions aortic stents 224, 241 aortofemoral bypass grafts salvage procedures 378–9 selective catheterization 110 aortography 121, 128–9 aortoiliac arteriography 121, 128 aortoiliac bypass grafts salvage procedures 378, 380 aortoiliac interventions access site management 353 access-related issues 327 aortic bifurcation 318 aortoiliac reconstruction 316, 317 covered stent use 326 heparin administration 198 infrarenal aorta 311–18 selective catheterization 90 self-expanding versus balloonexpanding stents 326 supplies for 312 aortoiliac occlusive disease 345 patterns of 346 see also iliac artery occlusions apixaban 146 argatroban 146 arterial palpation 9–10 arterial pressure monitoring 5

arterial rupture 217–18, 252 arteriographic fakeouts 133–4 arteriography 63 abdominal aortography 128 after hip or knee replacement 129 aneurysms 136–7 arch aortography 276–7 artifacts 133–4 brachiocephalic arteries 123–6 carotid arteries 123–5 catheter placement 118–19 completion arteriography 201–3, 221 contrast administration 119 diabetic ischemic foot lesions 132–3 duplex scanning 137 femoral arteries 129–30 future need for 113–14 iliac arteries 128 image acquisition 120 lessons learned from 113 occluded arteries 171, 172 patient evaluation 115–16 pedal 131–3 planning 114–15 puncture site selection 116–18 purposes 113 questions to consider 115 remote puncture sites 69 renal arteries 127–8 special views 134, 135 subclavian arteries 126 supplies for 114 thoracic aortography 126 tibial arteries 130–1 vertebral arteries 126 vessel diameter measurement 194 visceral arteries 126 arteriography pack 114 arteriography sequences 120–1 arteriovenous fistulae 24 aspirin 146 atherectomy 258–9, 360, 362 directional 259–60 femoral and popliteal arteries 355 laser 261 rotational (orbital) 260 axillary angioplasty 220, 292, 294 retrograde approach 296 transfemoral approach 294–6 axillary arteriography 121

axillary artery anatomic manipulations 189 exposure 8 occlusions 179, 180, 181 axillary artery conduits 400, 401 axillofemoral bypass grafts salvage procedures 378 selective catheterization 110 balloon angioplasty acute occlusion management 219 after aortic graft placement 405 aortic bifurcation 318–19 arterial rupture 217–18 assessment of results 202, 221 balloon inflation 198–201 balloon preparation and placement 197, 198 balloon removal 201 balloon reuse 202 balloon selection 193–5 balloon sizing 194 bidirectional 360, 361 common carotid artery 279, 280 common iliac artery 323 completion arteriography 201–3 cryoplasty 264–5 cutting balloons 262–4 dilation of atherosclerotic waist 200–1 dissection 191, 208–10 degrees of 228 stent placement 220, 227–9, 230 drug-coated balloons 261–2 embolization management 218–19 embolization risk 208 extra-anatomic bypasses 378 femoral and popliteal arteries 354 heparin administration 197–8 iliac arteries 397, 398 infrainguinal arteries ipsilateral antegrade approach 331, 332–3 up-and-over approach 336–7 infrainguinal bypass grafts 375–8 infrarenal aorta 313–14 kissing balloons 210 monorail systems 195 multiple lesions 205–7 within occluded stents 374

Index 443

balloon angioplasty (continued) pain 201, 210–11 arterial rupture 217 predilation 207–8 puncture site thrombosis prevention 212–13 recurrent stenosis 229, 230, 373–4 renal artery 304, 306–7, 308 residual stenosis 211–12, 229, 230 scoring balloons 263–4 sheath selection and placement 196–7 sheath tip location 207 spasm 211 subclavian and axillary arteries 294, 296 supplies for 195–6 technical aspects in different vascular beds 219–21 technique 193, 198 tibial artery 342–4, 365–6 troubleshooting 213–17 balloon catheters 192–3 sizing issues 152 use in sheath placement 160, 161, 340, 341 balloon diameter 193–4, 195 balloon emptying problems 215, 216, 217 balloon-expandable stents 223–4 aortoiliac segment 317–18, 319–20, 326 bailout maneuvers balloon rupture 247, 248 dissection at the end of a stent 247, 249 kinked sheaths 245, 246 loose stents 247, 248 stent embolization 247 stent tilts 247, 249 covered 226 hand crimping 231 placement technique 231–4 without a crossing sheath 245, 246 predilation 230–1 sizing issues 152–3 stent size 230 tapering a stent 243, 244 telescope effect 234 working qualities 239–40

balloon herniation 213–14, 216, 217 balloon length 194, 195 balloon rupture 213, 215, 217 balloon-expandable stents 247, 248 below the ankle angioplasty 371 bidirectional approach 359–60, 361 bivalirudin 146 bleeding 16, 24 from around the sheath 161 excessive 148 bolus chase method 79, 120, 128, 129 bovine arch 111 brachial angioplasty 220 brachial artery, selective catheterization 98 brachial artery occlusions 180, 181 brachial artery puncture 8, 21–3, 25, 158 brachiocephalic arteries arteriography 123–6 selective catheterization 90, 91–2 brachiocephalic interventions arch assessment 275, 277 arch branch lesions assessment 276–7 carotid bifurcation stenting 281–6 cerebral protection 287–8 heparin administration 198 innominate and carotid artery 275–6 open cell, closed cell, and mesh-covered carotid stents 286–7 principal techniques 277–9 retrograde approach to the common carotid artery 292, 293 subclavian and axillary arteries 292, 294 retrograde approach 296 transfemoral approach 294–6 transcarotid artery revascularization (TCAR) 288–91 transfemoral approach to the common carotid artery 279–81 bradycardia, post-CAS placement 286 buckling 69–70

buckling technique 42 buddy wires 51, 160 bypass grafts angioplasty 375–8 percutaneous puncture 23–4, 25 selective catheterization prosthetic grafts 109–11 vein grafts 108–9 C-arms 142–3 calcified lesions 353 crossing technique 186 iliac arteries 396–8 “candy wrapper” lesions 226 carbon dioxide arteriography 85, 134–5 carotid arteries aberrant anatomy 111, 112 anatomic manipulations 188–9 tandem lesions 292, 293 carotid arteriography 121, 123–5 heparinization 145 carotid bifurcation imaging 125 carotid bifurcation lesions, embolization risk 208 carotid bifurcation stenting 50, 275 embolic protection 284 removal of 285 guidewire–catheter technique 281–4 patient preparation 281 post-procedure management 286 spasm 285 stent placement 285 carotid interventions angioplasty 219, 220 balloon catheter length 195 choice of platform 50 potential guidewire misplacement 66 selective catheterization 90 sheath placement 159–60 stent placement 230, 288–91 arch assessment 275, 277 cerebral protection 287–8 distal protection devices 269–70 open cell, closed cell, and mesh-covered stents 286–7 transcervical approach 287

444   Index

carotid–subclavian bypass grafts 413–14 selective catheterization 110 catheter behavior 58 catheter handling 58–61, 63 buckling 69–70 failure to follow guidewire 67 failure to pass the catheter 70–1 guidewire and catheter combinations 65 initial placement 63–5 passing through diseased arteries 66–7, 68 aneurysms 72–3 dissected arteries 71–2, 74–5 stent–grafts 75 stents 72 remote puncture sites 69 tortuous arteries 67–8 see also guidewire–catheter skills catheter head shape 54–8 dependence on guidewire position 56 evaluation of 65 modification of 89 catheter lengths 54 catheter occlusion of an artery 133 catheters 53, 55 angiographic catheters 53–4 balloon catheters 192–3 contrast media flow rates 58 crossing catheters 257–8 CTO support catheters 172–3, 175, 257 laser catheters 261 microcatheters 255 re-entry catheters 256–7 sizing issues 32, 151 catheterization laboratories 141–2 celiac arteriography 121, 127, 134 celiac artery aberrant anatomy 111 approach to 297–8 selective catheterization 90, 98–9, 298–9, 301 transbrachial approach 301–2 stent placement 301 cephalosporin antibiotics 145 cerebral arteriography 124–5 cerebral catheters 55, 92–3, 124–5

cerebral protection 208, 287–8 see also distal protection devices chemical thrombolysis 266–8 chronic total occlusion (CTO) catheters and guidewires 172–3, 174, 257 clindamycin 145 clopidogrel 146–7 closed cell stents 225, 286 closure devices 25, 34, 353, 429–32 local anesthesia 145 CO2 arteriography 85, 134–5 coaxial systems 47 coil embolization 419–21 internal iliac artery 422–3 technique 421–2 coincidental lesions 71 collagen plug-mediated closure devices 431, 432 collateralized arteries arteriography 171 crossing occlusions 171–2 crossing stenoses 166–7 in the foot 367 common carotid arteries, selective catheterization 94–5 common carotid arteriography 125 common carotid artery puncture 8 common carotid interventions 275–6 principal techniques 277–9 retrograde approach 292, 293 stent placement 50 supplies for 276 transfemoral approach 279–81 common iliac interventions balloon angioplasty 323 selective catheterization 90 common iliac occlusions 179 comorbidity 115 completion arteriography 201–3, 221 complex curve catheters 55, 57–8, 93 catheterization of aortic arch branch vessels 95–6 compliance of balloons 192 complications acute occlusion 219 of arterial puncture 15–16, 24, 432 arterial rupture 217–18 embolization 218–19 relationship to selectivity 89 of stent placement 252–3

conduits 398–401 conscious sedation 145 consent 4, 116 contralateral gate cannulation, aortic grafts 403, 405, 406 contrast administration 63, 119, 120, 121 after crossing a lesion 166 air bubble removal 84 arteriography of aneurysms 137 bolus chase method 129 cerebral arteriography 125 digital subtraction arteriography 79 power injectors 82–3 comparison with hand injection 83–4 contrast agents 4, 84–5 urinary excretion 134 use in balloon inflation 198–9 contrast allergies 115, 147 contrast-induced renal failure 115 contrast layering 133 contrast load 85 contrast media flow rates 58 coronary procedures, choice of platform 50 covered stents 225–6 placement technique 238 stent size 237–8 use in aortoiliac arteries 326 crossability of catheters 58 crossing a stent 245 crossing catheters 257–8 crossing devices 175 crossing lesions 42, 163 anatomic manipulations 188–9 calcified lesions 186 femoral and popliteal arteries 355–6 laser-assisted technique 260–1 lesion types 163–4 long lesions 186–7 occluded stents 374–5 occlusions 171–4, 181 chronic total occlusion catheters 257 iliac arteries 182–3, 350–1 infrarenal aorta 182 popliteal artery 184 renal artery 181–2 retrograde approach 184–5

Index 445

crossing lesions (continued) subclavian artery 178, 180 subintimal recanalization 173–4 superficial femoral artery 183 technique 175–6 tibial artery 184 tools available 174–5 true lumen crossing 172–3, 174 visceral arteries 181–2 procedure after guidewire placement 187–8 road mapping 170 stenoses 164–9 approach from opposite direction 167–8 avoiding subintimal guidewire dissection 169 imaging 164, 167 at the orifice of major branch arteries 168 tools available 164 well-collateralized arteries 166–7 support and directionality 164 cryoplasty 264–5 CT angiography aortic aneurysms 391–2 cutting balloons 262–3, 363, 364 dabigatran 146 Dacron grafts, percutaneous puncture 23–4, 25 debulking atherectomy 259 laser-assisted 261 descending thoracic aortography 121 diabetes duplex scanning 137 evaluation of ischemic foot lesions 132–3 dialysis grafts, angioplasty,194 digital subtraction arteriography (DSA) 79, 120 dilators 28, 29, 53, 149, 152 indications for use 30–2 sizing issues 32, 151 diphenhydramine, in contrast allergy 147 direct thrombin inhibitors 146

directional atherectomy 258, 259–60, 360, 362 diseased arteries guidewire–catheter skills 42, 68 selective catheterization 91 passage over aortic bifurcation 104 dissection at the end of a stent 247, 249, 252 flow-limiting 228 guidewire–catheter skills 71–2 aortic dissection 74–5 guidewire-induced subintimal dissection 169–70 postangioplasty 191, 208–10 degrees of dissection 228 stent placement 220, 227–9, 230 disseminated intravascular coagulation (DIC) 148 distal protection devices 269–71, 362 in carotid artery stenting 284, 287–8 in renal stenting 309 dorsalis pedis occlusions 184 double-wall puncture technique 14 drilling guidewires 45–6 drug-coated balloons (DCBs) 261–2 use in infrainguinal arteries 334 drug-eluting stents (DESs) 262 dual antiplatelet therapy 146–7 duplex scanning intraoperative 221 use in puncture site selection 118 use to limit arteriography requirements 137 edoxaban 146 electrocardiographic monitoring 5 embolic protection see distal protection devices embolization after stent placement 252 management 218–19 embolization risk balloon angioplasty 208, 214 aortic 313–14 crossing occlusions 171 femoral–popliteal occlusive disease 364–5 occluded stents 374 transfemoral carotid stenting 288

embolizing lesions, stent placement 229, 230 endarterectomy, hybrid procedures 383, 384 endo staples, in aortic graft placement 409 endoleak management, aortic aneurysm repair 414–17 endovascular concepts 3 endovascular skills 3 epinephrine, in contrast allergy 147 equipment 4–5, 143, 144 for balloon angioplasty 195–6 radiographic 86 exchange catheters 53, 54, 55 exchange guidewires 35, 38–40 excimer laser-assisted angioplasty 260–1, 362–3 external conduits 398–401 external iliac interventions postangioplasty dissection 209 selective catheterization 90 extra-anatomic bypasses salvage procedures 378 facility requirements 143–4 failure, mechanisms of 373 femoral arteriography 121, 129–30 femoral artery, disease extension of external iliac occlusions 353 femoral artery procedures angioplasty balloon sizing 194 pain 210 choice of platform 50–1 endarterectomy plus distal intervention 389 plus iliac stent 387–9 selective catheterization 90 femoral artery puncture 8 abandoning an access 21 anatomy 9–10 antegrade 17–19, 18 comparison of puncture site options 24–5 complications 15–16 fluoroscopic guidance 20 hostile groins 34 pulseless artery 19–20 retrograde 13–16 ultrasound guidance 11

446   Index

femoral bifurcation imaging 129, 134, 135 femoral–femoral bypass grafts salvage procedures 378 selective catheterization 110 femoral–popliteal occlusive disease bidirectional approach 359–60, 361 embolization risk 364–5 treatment techniques 355–6 atherectomy 360, 362 excimer laser-assisted angioplasty 362–3 scoring angioplasty 363 stent–grafts 363 subintimal angioplasty 356–9 subintimal recanalization 353–5 femoropopliteal angioplasty balloon catheter length 195 heparin administration 198 fentanyl 145 filming errors 133–4 filters for embolic protection 269–71, 287–8 in imaging 87 floating-point tables 5 floppy tip guidewires 38, 39, 41 crossing a lesion 42, 164–5 flow artifacts 133 flow-limiting dissection 228 fluoroscopy during femoral artery puncture 20 during guidewire passage 41 stationary versus portable imaging systems 142–3 when to use it 32, 63–4 see also imaging flush catheters 53, 54, 55, 56 sizes 151 focal force balloons 263 focal spots 87 foot angiosomes 367 foot ischemia, diabetic 132–3 forehand approach 9 fossa ovalis 10 frame rates 87 French caliber measuring system 32, 58

friction points 155 furosemide, in contrast allergy 147 gas artifacts 133 gastric artery, aberrant anatomy 111, 112 graft placement, aortic aneurysms 401–3 groin crease position 10 guidewire–catheter buckling 69–70 guidewire and catheter combinations 65 guidewire–catheter skills 35, 58–61, 63 abandoning the chosen guidewire 43–4 advancement 15, 28, 30 advancement problems 16–17 in arteriography 118–19 brachiocephalic interventions 277–8 buckling technique 42 failure to pass the catheter 70–1 handling techniques 35–6, 40–3 initial catheter placement 63–5 passing through diseased arteries 42, 66–7, 68 aneurysms 72–3 dissected arteries 71–2, 74–5 road mapping 81–2 stent–grafts 75 stents 72 pinning a guidewire 43 potential for entering the wrong location 65–6 remote puncture sites 69 selective catheterization 89–91 tightening the curve on the tip 40 torque devices 42 tortuous arteries 67–8 wire bias 67 guidewire characteristics coating 38 diameter 37 length 36–7 special features 38 stiffness 37 tip shape 38 guidewire choices 27, 35, 36 guidewire inventory 46

guidewire length requirements 40 guidewire–lesion interactions 36 guidewire modification drilling guidewires 45–6 loop creation 44–5 guidewires 38–40 coaxial systems 47 crossing lesions 164–9 avoiding subintimal guidewire dissection 169–70 CTO wires 174 maneuvers with small caliber wires 51 monorail systems advantages and disadvantages 49 comparison with coaxial systems 47–8 principles for use 49 small platform systems 47 starter platforms and switching platforms 50–1 guiding catheters 152, 156 sizing issues 151–2 guiding sheaths 152, 155–6 placement 156–8 for renal artery interventions 304, 305 sizing issues 151 hand injection of contrast 83–4 heart failure, arteriography 115 helical stents 225 hemorrhage 16, 24 from around the sheath 161 excessive 148 hemostasis 427 holding pressure 427–9 in hybrid procedures 384 inflow balloon occlusion 386–7 heparin administration 89, 145–6, 197–9 heparin allergy 148 heparin alternatives 146 heparin-induced thrombocytopenia 148 heparin resistance 146, 148, 197 hepatic artery, aberrant anatomy 111, 112 high-pressure balloons 193

Index 447

hip replacements, arteriography 129 history-taking 6 hostile groins 34 hybrid procedures in aortic disease 413–14 arterial puncture and sheath placement 384–6 endarterectomy 383, 384 examples 381, 382 femoral endarterectomy plus distal intervention 389 hemostasis 384 iliac stent and femoral endarterectomy 387–9 inflow balloon occlusion 386–7 order of procedures 383 preparation 381 principles 381 working room 383 hydrophilic guidewires, crossing lesions 165 hypercoagulable states 148 hypotension, post-CAS placement 286 iliac angioplasty 220, 221, 323 balloon catheter length 195 balloon sizing 194 completion arteriography 203 pain 210 iliac arteries 116 access challenges 394, 396 artery size 396–7 calcification 396 diseased arteries 397, 398 tortuosity 397–8, 399 anatomic manipulations 189 approaches to 321, 322, 324, 347–8 contralateral approach 322, 323–6 ipsilateral retrograde approach 321–3 internal iliac artery coiling 422–3 postangioplasty dissection 209 iliac arteriography 116, 128, 134 iliac artery catheterization 100–5 iliac artery conduits 400 iliac artery occlusions 179, 182–3 approaches to 347–8 assessment 345, 347–8

extension to femoral arteries 353 patterns of 346 recanalization technique 349–52 treatment options 345 iliac bifurcation imaging 134, 135 iliac rupture 217–18 iliac stents 224, 241, 323, 325–6 after aortic graft placement 406–7 plus femoral endarterectomy 387–9 iliofemoral bypass grafts salvage procedures 378 selective catheterization 110, 111 image quality 77–8 imaging 77 aortic aneurysms 391–2 automated power injectors 82–3 contrast agents 84–5 contrast load 85 digital subtraction arteriography 79 equipment 86 pretreatment 6 radiation exposure 87 radiographic terms 86–7 resolution enhancement 80–1 road mapping 81–2 safety and occupational health issues 86 stationary versus portable systems 142–3 stenoses 164, 167 X-ray image generation 78–9 see also fluoroscopy infection 253 inferior mesenteric artery (IMA) 318 inflation devices 199 inflow balloon occlusion 386–7 infrainguinal arteries 329 balloon angioplasty 331–3, 336–7 selective catheterization antegrade approach 106, 331–3 comparison of approaches 330 tibial arteries 106–8 up-and-over approach 105–6, 329–30, 334–41 stent placement 333–4 see also popliteal artery; superficial femoral artery; tibial artery

infrainguinal bypass grafts angioplasty 194 salvage procedures 375–8 selective catheterization 108–9 infrapopliteal angioplasty, balloon catheter length 195 infrapopliteal arteriography 129 infrarenal aortic interventions access 311–13 balloon angioplasty 313–14 embolization 313–14 IMA management 318 selective catheterization 90 stent placement 313, 314–18 infrarenal occlusive disease 179, 182 arteriography 116, 117 inguinal ligament 9 innominate arteriography 121, 125 innominate interventions 275–6 principal techniques 277–9 selective catheterization 94 stenting 50 supplies for 276 insulin, dosage prior to arteriography 115 internal conduits 399–400 internal iliac interventions coil embolization 422–3 selective catheterization 90 intimal hyperplasia 253, 373 intraoperative duplex ultrasound 221 intravascular ultrasound (IVUS) 137–8, 221 inventory see equipment iohexol 84 iopamidol 84 iotrolan 84 ioversol 84 J-tip guidewires 39, 40 kilovoltage (kV) 86–7 kinked sheaths 245, 246 kissing balloons 210, 318–19 sizing issues 194 kissing stents 242, 317, 319–20, 351 knee replacements, arteriography 129 large bore access 392–4 laser-assisted angioplasty 260–1, 362–3

448   Index

left anterior oblique (LAO) projection 123, 134 lesion types 163–4 lidocaine 145 local anesthetic 145 long lesions, stent placement 230 loose stents 247, 248 lower extremity runoff 128–9 MAS (milliamperes/second) 87 mask image 87 matrix, digital 87 mechanical thrombolysis 266–7, 268–9 medical management 4 medications antibiotics 145 anticoagulation 145–6 antiplatelet agents 146–7 local anesthetic 145 sedation and analgesia 145 thrombolysis 147 vasodilators 147 meglumine contrast agents 84 mesh covered carotid stents 286–7 metformin 115 microcatheters 255–6 micropuncture set 12 micropuncture technique 12 midazolam 145 monitoring 5 monorail systems 195 advantages and disadvantages 49 balloon preparation and placement 197 comparison with coaxial systems 47–8 principles for use 49 multiple lesions balloon angioplasty 205–7 see also hybrid procedures nitinol stents 224–5 placement technique 235–7 stent size 235 working qualities 239–40 nitroglycerine 147 “no touch” technique 91, 305, 307 nylon catheters 53 obesity 115 pannus management 18, 19

oblique projections 164, 167 post-balloon angioplasty 221 occluded stents 374–5 occlusion balloons 287, 386–7 occlusions acute 219 after stent placement 252 aortic 352–3 arteriography 171, 172 axillary artery 180 brachial artery 180 crossing lesions 171–2, 175–6, 181 anatomic manipulations 188–9 chronic total occlusion catheters 257 lasers 260–1 procedure after guidewire placement 187–8 retrograde approach 184–5 subintimal recanalization 173–4 tools available 174–5 true lumen crossing 172–3, 174 guidewire modification 44–6 iliac artery 182–3, 345–52 infrarenal aorta 182 popliteal artery 184 renal arteries 181–2 stent placement 229, 230 subclavian arteries 178, 180 subintimal angioplasty 176–8 superficial femoral artery 183 tibial artery 184 visceral arteries 181–2 occlusive devices, embolic protection 271 occupational health issues 86 open cell stents 225, 286 operating rooms 141–2 opiates 145 orbital atherectomy 260, 362 orifice lesions 168 over-the-bifurcation approach see up-and-over approach oxygen monitoring 5 paclitaxel 261–2 pain arterial rupture 217 during balloon angioplasty 201, 210–11 pannus management 18, 19 papaverine 147

parallax 133 paravisceral aortography 121 patent “occlusion” 134 patient evaluation 3–4, 6 prior to arteriography 115–16 pedal arteriography 131–2, 134 diabetic ischemic foot lesions 132–3 viable foot/no outflow 134 pedal artery puncture 8, 9, 23, 368–71 choice of platform 50 pedal interventions 220, 221, 371 heparin administration 198 pain 210–11 selective catheterization 90 pedal loop 367 pelvic arteriography 129 percutaneous vascular access see access peroneal artery, area served by 367 personnel 143, 144 physical examination 6 arterial palpation 9–10 pigtail catheters 55, 92 exchanging 124 pinning a guidewire 43 plantar artery occlusions 184 plaque fracture 191 polyethylene catheters 53 polyurethane catheters 53 popliteal aneurysms 424–5 popliteal arteriography 134 popliteal artery anatomic manipulations 189 approaches antegrade approach 106, 330, 331–4 comparison of 330 up-and-over approach 105–6, 329–30, 334–41 rupture 218 see also femoral–popliteal occlusive disease popliteal artery interventions angioplasty 220, 221, 336–7 balloon sizing 194 dissection 209 pain 210 choice of platform 50–1 potential guidewire misplacement 65–6 selective catheterization 90 stent placement 227, 241

Index 449

popliteal artery occlusions 179, 180, 184 popliteal artery puncture 8, 23 popliteal vein 23 portable imaging systems 142–3 postangioplasty dissection degrees of 228 stents 227–9, 230 posterior tibial artery, area served by 367 posterior wall lesions 133 power injectors 82–3, 119 comparison with hand injection 83–4 pre-close technique 392–4, 395 predilation 207–8, 363 prednisone, in history of contrast allergy 147 pressure application, puncture sites 427–9 pressure gradients 229 pressure measurement 136, 221 in postangioplasty dissection 228–9 primary stent placement 226, 230 “priming” balloon catheters 197 profunda femoris artery 134 prosthetic bypass grafts selective catheterization 109–11 see also bypass grafts protamine sulfate 146 proximal access 21, 25 brachial artery puncture 21–3 proximal protection devices 271, 287, 288 pseudoaneurysms 24 pulse spray technique, thrombolysis 267 pulseless femoral artery 19–20 pulses 6 femoral 10 puncture site choice 8–9, 24–5 for arteriography 116–18 for endovascular therapy 149 puncture site complications 15–16, 24, 34, 432 puncture site management closure devices 429–32 holding pressure 427–9 obtaining hemostasis 427 timing sheath removal 429 puncture site thrombosis prevention 212–13

pushability of catheters 58 push–pull technique 59 radial artery, aberrant anatomy 111 radial artery puncture 8 radiation exposure 87 radiation protection 87 radiation safety 86 radiographic equipment 86 radiographic terms 86–7 rapid exchange systems see monorail systems recurrent stenosis 229, 230, 373–4 renal artery 309 re-entry catheters 256–7, 360 re-entry devices 175 remote puncture sites 69 renal arteriography 121, 127–8, 134 renal artery aberrant anatomy 111, 112 mobility with breathing 303–4 selective catheterization 99–100, 303–5 renal artery interventions 220–1 approach 302–3 balloon angioplasty 304, 306–7, 308 balloon catheter length 195 balloon sizing 194 distal protection devices 309 guiding sheath tips 305 heparin administration 198 pressure drops 305 recurrent stenosis 309 stent placement 50, 223–4, 241, 306, 307–9 supplies for 302 renal artery lesions 168 occlusions 179, 181–2 renal catheters 55, 57 positioning, bony landmarks 64 renal insufficiency 4 arteriography 115–16 residual stenosis, stent placement 229, 230 resuscitation equipment 5 retrograde approach crossing occlusions 184–5 to tibial artery 368–71 retrograde femoral puncture 13–16, 24–5 for arteriography 116

retroperitoneal hemorrhage 16 rivaroxaban 146 road mapping 81–2, 165, 170 room set-up 5–6 rotational atherectomy 260, 362 runoff, assessment of acute results of angioplasty 221 ruptured aortic aneurysms 411–13 salvage procedures 373–4 aortoiliac bypass grafts 378 extra-anatomic bypasses 378 infrainguinal bypass grafts 375–8 occluded stents 374–5 sciatic artery, persistent 111, 112 scoring angioplasty 363 scoring balloons 263–4 sedation 145 selective catheterization 89–91 aortic arch branches 93–8 brachiocephalic arteries 91–2 catheter options 90 celiac and superior mesenteric arteries 98–9, 298–9, 301 cerebral catheters 124–5 infrainguinal arteries 105–8 infrainguinal vein bypass grafts 108–9 passage over aortic bifurcation 100–5 prosthetic bypass grafts 109–11 renal artery 99–100, 303–5 selective catheters 53, 54, 55, 56–8, 90 cerebral 55, 92–3 sizes 151 selective guidewires 38, 39 selective stent placement 226 self-expanding stents 224–5 aortoiliac segment 316–17, 319, 326 bailout maneuvers extension into an undesired location 250 extension into hemostatic introducer sheath 250, 251 failure to fully expand 249–50 inaccurate location 250, 251 mid-section collapse 250, 252 covered 225–6 moving 243–5 placement technique 235–7 tapering a stent 242–3 working qualities 239–40

450   Index

serration angioplasty 363 sheath access 27, 33 sheath exchanges 150 sheath length 150 sheath obstructions 155 sheath placement 28–30, 33, 153–5, 196–7 calcified, thickened, or scarred arteries 31 difficult 160–1 dilators 28, 31–2 guiding sheaths 156–8 hybrid procedures 384–6 in remote branch arteries 159–60 through open arteriotomy 385 sheath-related trouble shooting 161 sheath removal 427 holding pressure 427–9 timing 429 sheath size 32, 149–50, 151 sheath tip location 207 sheath upsizing 33 sheath-within-a-sheath technique 155, 339 shoulder length, balloon angioplasty 195 simple curve catheters 55, 57, 58 selective catheterization 92–3 single-wall puncture technique 14 sizing issues 32, 149–50, 151 access sheaths and guiding sheaths 151 balloon catheters 152, 192, 193, 194 catheters 151 dilators 151 guidewires 36–7, 150–1 guiding catheters 151–2 stents 152–3 skin incisions 28 small platform systems 47 indications for use 50 special maneuvers 51 snorkel grafts 407–9 soaker hose catheters 267 sodium diatrizoate 84 spasm 133, 211 special procedures suites 141–2 standing waves 133 starter platforms 50

stationary imaging systems 142 steerability of catheters 58 steerable guide sheaths 299–301 steerable tip guidewires 38, 40 crossing lesions 165 torque devices 41, 42 stenoses crossing lesions 164–9 recurrent 229 residual after angioplasty 229 stent choices 223–5 stent comparisons 239–40 stent embolization 247, 252 stent–grafts 225, 226, 265–6, 354, 363 femoral and popliteal arteries 355 guidewire–catheter skills 75 iliac arteries 352 popliteal aneurysms 424–5 stent migration 252 stent occlusion, embolization risk 208 stent placement acute complications 252 antiplatelet therapy 147 aortic bifurcation 104, 319–20 balloon-expandable stents 230–4 bailout maneuvers 245–9 carotid bifurcation 281–6 TCAR approach 288–91 chronic complications 253 common carotid artery 279–81 covered stents 237–8 femoral and popliteal arteries 354–5 guidewire–catheter skills 72 iliac arteries 323, 325–6, 351–2, 397, 398 infrainguinal arteries ipsilateral antegrade approach 333–4 infrarenal aorta 313 in postangioplasty dissection 209–10, 220 primary versus selective 226 renal artery 306, 307–9 repeat treatments 374 managing occluded stents 374–5 in residual stenosis 211–12 self-expanding stents 235–7 bailout maneuvers 249–52 sheath size 196

subclavian and axillary arteries 294–6 superior mesenteric artery 300 tibial artery 343, 344 tricks of the trade crossing a stent 245 kissing stents 242 moving a self-expanding stent 243–5 placement of a balloonexpandable stent without a crossing sheath 245, 246 tapering a stent 242–3, 244 stent selection 238, 241–2 stents covered 225–6 drug-eluting 262 impact of 223 indications for use 226–7, 230 embolizing lesions 229 occlusion 229 postangioplasty dissection 191, 227–9 pressure gradients 229 recurrent stenosis 229 residual stenosis 229 sizing issues 152–3 straight catheters 55, 56 subclavian angioplasty 220 balloon catheter length 195 balloon sizing 194 subclavian arteriography 121, 126 subclavian artery aberrant anatomy 111, 112 anatomic manipulations 189 selective catheterization 94, 95, 96–8 subclavian artery occlusions 178, 180, 181 subclavian artery stents 50, 241 subclavian interventions 275–6, 292, 294 approaches antegrade approach 96 retrograde approach 96, 98, 296 transfemoral approach 294–6 potential guidewire misplacement 66 principal techniques 277–9 selective catheterization 90 supplies for 276

Index 451

subintimal angioplasty 176–8, 356–9 subintimal dissection, guidewireinduced 169–70 subintimal recanalization 173, 356 re-entry catheters 256–7 re-entry devices 175 superficial femoral artery occlusions 179, 180, 183 superficial femoral artery puncture 8, 23 superficial femoral artery (SFA) 150 approaches comparison of 330 ipsilateral antegrade approach 106, 107, 330–4 up-and-over approach 105–6, 329–30, 334–41 balloon angioplasty 220, 221, 331, 332–3 duplex scanning 137 occlusions arteriography 171 postangioplasty dissection 209 rupture 218 stent placement 227, 241, 333–4 superior mesenteric arteriography 121, 127, 134 superior mesenteric artery selective catheterization 90, 98–9, 297–9 transbrachial approach 301–2 stent placement 300 suture-mediated closure devices 430, 431–2 table design 5 tandem carotid lesions, hybrid approach 292, 293 tapering a stent 242–3, 244 telescope effect, balloonexpandable stents 234 “telescoping” technique 155, 160 tennis racket catheters 55 thoracic aortic stent grafts 414 thoracic aortography 121, 126 thrombectomy 268–9 thrombocytopenia, heparininduced 148 thrombolysis 147, 266–8 thrombosis, prevention at puncture site 212–13

thrombotic occlusive disease, arteriography 114 thrombus, excessive formation of 147–8 through-and-through wires 402, 404–5 tibial arteriography 130–1, 134 tibial artery aberrant anatomy 111, 112 anatomic manipulations 189 rupture 218 tibial artery interventions 341–2 balloon angioplasty 220, 221, 342–4 balloon sizing 194 heparin administration 198 pain 210–11 selective catheterization 90, 106–8 stent placement 343, 344 tibial artery occlusions 171, 180, 184 angioplasty for limb salvage 365–6 how many arteries to treat 366–7 retrograde approach 368–71 tibial artery puncture 8, 9, 23 choice of platform 50 tibiopedal arteriography 121 tilted stents 247, 249 tissue plasminogen activator (tPA) 147, 267 torque devices 41, 42 tortuosity anatomic manipulations 188–9 in carotid artery stent placement 285 guidewire–catheter skills 67–8 iliac arteries 397–8, 399 passage over aortic bifurcation 104 selective catheterization 90 sheath placement 30, 33, 155 trackability of catheters 58 transcarotid artery revascularization (TCAR) 288–91 reversed flow circuit 290 stent placement 291 translumbar artery puncture 8, 9 transluminal recanalization 172–3, 174, 356 trouble shooting, sheath-related 161

ultrasound guidance 10–12 ultrasound imaging aortic aneurysms 391–2 intraoperative duplex scanning 221 intravascular 137–8 up-and-over approach 105–6, 157, 158, 329–30, 334–7 access difficulties 337–41 vascular access see access vasodilators 147 venous puncture, ultrasound guidance 11–12 vertebral arteriography 126 vertebral artery protection during subclavian artery procedures 178, 180, 295–6 selective catheterization 98 vertebral catheters 58 vessel occluders 423–4 vessel preparation 363–4 visceral angioplasty 220–1 balloon catheter length 195 visceral arteries approach to 297 selective catheterization 90, 98–9 see also celiac artery; superior mesenteric artery visceral arteriography 126–7 visceral artery occlusions 179, 181–2 visceral stenting 50 “walking along” the guidewire 60 warfarin 146 prior to arteriography 115 water-hammer pulse 10 wire bias 67 working environment 4, 141 ideal components 143 operating room versus special procedures suite 141–2 stationary versus portable imaging systems 142–3 working room hybrid procedures 383 inadequate 213, 214 woven nitinol stents 225 X-ray image generation 77–8