(BQ) Part 1 book USMLE road map - Genetics presents the following contents: Vascular pathology, fundamentals of angiography, noninvasive vascular imaging, vascular interventions, carotid and vertebral arteries, upper extremity arteries,...
THE REQUISITES Vascular and Interventional Radiology Second Edition John A Kaufman, MD, MS, FSIR, FCIRSE Director, Dotter Interventional Institute Frederick S Keller Professor of Interventional Radiology Oregon Health & Science University Hospital Portland, Oregon Michael J Lee, MSc, FRCPI, FRCR, FFR(RCSI), FSIR, EBIR Consultant Interventional Radiologist, Beaumont Hospital Professor of Radiology, Royal College of Surgeons in Ireland Department of Radiology, Beaumont Hospital Dublin, Ireland 1600 John F Kennedy Blvd Ste 1800 Philadelphia, PA 19103-2899 VASCULAR AND INTERVENTIONAL RADIOLOGY: THE REQUISITES ISBN: 978-0-323-04584-1 Copyright © 2014 by Saunders, an imprint of Elsevier Inc Copyright © 2004 by Mosby, Inc., an affiliate of Elsevier Inc No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein) Notices Knowledge and best practice in this field are constantly changing As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility With respect to any drug or pharmaceutical products identified, readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications It is the responsibility of practitioners, relying on their own experience and knowledge of their patients, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein Library of Congress Cataloging-in-Publication Data Kaufman, John A., author Vascular and interventional radiology: the requisites / John A Kaufman, Prof Michael J Lee.—Second edition p ; cm.—(Requisites) (Requisites in radiology series) Includes bibliographical references and index ISBN 978-0-323-04584-1 (hardcover) I Lee, Michael J., author II Title III Series: Requisites series IV Series: Requisites in radiology [DNLM: Vascular Diseases—radiography Radiography, Interventional—methods WG 500] RD598.67 617.4’13059 dc23 2013009169 Senior Content Strategist: Don Scholz Content Development Specialist: Margaret Nelson Publishing Services Manager: Deborah Vogel Project Manager: Brandilyn Flagg Designer: Steve Stave Printed in China Last digit is the print number: 9 8 7 6 5 4 3 2 For our children, Nick, Claire, and Alex You are everything to us John and Cathy Kaufman For Eileen, Aoife, Ronan, Daire, and Sarah, and my parents Joe and Rose Michael J Lee Contributors Michael D Beland, MD Assistant Professor Department of Diagnostic Imaging Alpert Medical School of Brown University; Director of Ultrasound Department of Diagnostic Imaging Rhode Island Hospital Providence, Rhode Island Chapter 25: Image-Guided Tumor Ablation: Basic Principles Peter J Bromley, MD, FRCPC Consultant Radiologist Departments of Radiology and Surgery Peter Lougheed Centre Calgary, Alberta, Canada Chapter 14: Portal and Hepatic Veins Xavier Buy, MD Department of Interventional Radiology University Hospital of Strasbourg Strasbourg, France Chapter 24: Musculoskeletal Intervention Colin P Cantwell, FRCR, FFR Consultant Interventional Radiologist Radiology Department St Vincent’s University Hospital Dublin, Ireland Chapter 26: Image-Guided Ablation of Renal Tumors Chapter 28: Image-Guided Ablation of Liver Tumors Damian E Dupuy, MD, FACR Professor of Diagnostic Imaging Department of Diagnostic Imaging Alpert Medical School of Brown University; Director of Tumor Ablation Department of Diagnostic Imaging Rhode Island Hospital Providence, Rhode Island Chapter 27: Image-Guided Ablation as a Treatment Option for Thoracic Malignancies Afshin Gangi, MD, PhD Professor University of Strasbourg; Department of Interventional Radiology Nouvel Hopital Civil (NHC) Strasbourg, France Chapter 24: Musculoskeletal Intervention Debra A Gervais, MD Division Chief, Abdominal Imaging and Intervention Division Chief, Pediatric Imaging Assistant Program Director, MGH Radiology Residency Massachusetts General Hospital and Harvard Medical School Boston, Massachusetts Niamh Hambly, MBBChBAO, MRCPI, FFR(RCSI) Consultant Radiologist Beaumont Hospital Dublin, Ireland Chapter 23: Image-Guided Breast Intervention Farah G Irani, MD Department of Interventional Radiology University Hospital of Strasbourg Strasbourg, France Chapter 24: Musculoskeletal Intervention Alice M Kim, MD Clinical Instructor of Radiology Department of Radiology New York Hospital Queens—New York Presbyterian – Weill Cornell Medical College; Radiologist Department of Radiology New York Hospital Queens Flushing, New York Chapter 27: Image-Guided Ablation as a Treatment Option for Thoracic Malignancies William W Mayo-Smith, MD, FACR Professor of Radiology Alpert Medical School of Brown University; Director of CT and Body Imaging & Intervention Department of Radiology Rhode Island Hospital Providence, Rhode Island Chapter 25: Image-Guided Tumor Ablation: Basic Principles Gary M Nesbit, MD Professor Dotter Interventional Institute, Radiology, Neurosurgery, and Neurology Oregon Health & Science University Portland, Oregon; Adjunct Associate Professor Department of Radiology University of Utah Salt Lake City, Utah Chapter 5: Carotid and Vertebral Arteries Constantino S Pena, MD Affiliate Assistant Professor Department of Radiology University of South Florida College of Medicine Tampa, Florida; Medical Director of Vascular Imaging Department of Interventional Radiology Baptist Cardiac and Vascular Institute Miami, Florida Chapter 3: Noninvasive Vascular Imaging Chapter 26: Image-Guided Ablation of Renal Tumors Chapter 28: Image-Guided Ablation of Liver Tumors vii Foreword The first edition of Vascular and Interventional Radiology: THE REQUISITES was the tenth book in the series and shared the overall series goal of providing core material in major subspecialty areas of radiology for use by residents and fellows during their training and by practicing radiologists seeking to review or expand their knowledge The original book achieved its goals in outstanding fashion and now it is time for the second edition, which reflects the rather remarkable strides that have been made in vascular and interventional radiology over the past several years As noted previously, each book in THE REQUISITES series has offered a different set of challenges In the case of vascular and interventional radiology, a major challenge for the second edition was the need to cover many new procedures and provide outcomes information for procedures that have begun to mature Examples from the two ends of the spectrum include the transformative development of regional delivery of targeted therapies and the growing body of knowledge about outcomes in the use of percutaneously implanted devices and stents Drs Kaufman and Lee have again done an outstanding job of distilling this important material and the basic concepts of vascular and interventional radiology into a text that achieves high marks for readability and accessibility There is no subspecialty area of radiology more vulnerable to turf battles than vascular and interventional radiology It is imperative that radiologists continue to acquire skills in this area if the specialty is going to remain a strong provider of these services One of the great advantages that radiologists have is their superior knowledge of imaging, which is of course the guiding hand of both diagnostic and therapeutic interventions Drs Kaufman and Lee have richly illustrated their book to reflect the flexibility of multi-modality imaging that is now associated with performing interventions In surgery morbidity is often linked to the amount of normal tissue that must be compromised in order to reach—visualize—diseased tissues By using noninvasive imaging to achieve visualization and minimally invasive percutaneous access to treat disease, interventional radiology simply offers a better option than traditional open surgery for many conditions One of the major strengths of THE REQUISITES series has been the continuity of authorship from one edition to the next, allowing authors to build on their work while updating it appropriately The current book is as fresh and relevant to today’s contemporary practice of vascular and interventional radiology as its predecessor The book also continues to be comprehensive enough to serve as both an introductory text to the subject material covered and an efficient source for review prior to examinations While the length and format of each volume in THE REQUISITES series are dictated by the material being covered, the principal goal of the series is to equip the reader with a text that provides the basic factual, conceptual, and interpretive material required for clinical practice I believe residents in radiology will find that the second edition of Vascular and Interventional Radiology: THE REQUISITES is an excellent tool in these respects for learning the subject Drs Kaufman and Lee have again captured the most important material in a very user-friendly text In addition to residents, physicians in practice and those undertaking fellowship programs in vascular and interventional radiology will also find this book extremely useful For seasoned practitioners and fellows alike, Vascular and Interventional Radiology: THE REQUISITES provides the material they need for contemporary clinical practice I congratulate John Kaufman and Michael Lee for another outstanding contribution to THE REQUISITES in Radiology James H Thrall, MD Radiologist-in-Chief Department of Radiology Massachusetts General Hospital; Juan M Taveras Professor of Radiology Harvard Medical School Boston, Massachusetts ix Preface The specialty of interventional radiology has never been, and never will be, static, boring, or easily characterized With a unique combination of imaging, procedures, medicine, technology, and clinical variety, there is hardly a more exciting specialty Imageguided, minimally invasive therapies are recognized by patients and other physicians as the way of the future, and interventional radiology is at the center The origins of this specialty lie in diagnostic imaging In the era before cross-sectional imaging, the only nonoperative way to evaluate many pathologic conditions was to put needles into the recesses of the body, such as blood vessels, bile ducts, renal collecting systems, subarachnoid spaces, and peritoneal cavities, and then inject contrast In 1964 in Portland, Oregon, Charles Dotter performed the first percutaneous transluminal angioplasty (see Fig 4-1) This shifted the whole paradigm Radiologists who performed angiography and other special diagnostic procedures began to think of themselves as interventionalists Not only could they diagnose the disease, but they could treat it as well Slowly but inevitably, procedures that once required surgeons and surgical incisions have been replaced by interventionalists using percutaneous image-guided techniques Percutaneous catheter drainage of abdominal abscesses has all but supplanted open “I & D.” More recently transcatheter uterine artery embolization for symptomatic fibroids has become a major alternative to hysterectomy With each technological innovation, the number and breadth of procedures increases The impact of the percutaneously delivered intravascular metallic stent, particularly on the management of arterial occlusive and aneurysmal disease, has been enormous Embolization and other procedures are now essential to the management of patients with advanced solid tumors in many organs Once dismissed as fringe practitioners of dangerous and unproven arts, interventional radiologists have become indispensable to the daily functioning of the medical system Although we will never lose our imaging roots, interventional radiologists are increasingly participants in the clinical care of many different kinds of patients Make no mistake about it; interventional radiology is here to stay The impact of image-guided interventions has not gone unnoticed by the rest of medicine Early in our history, cardiologists determined that cardiac catheterization should move from radiology, where it was developed, to medicine, because that was where the heart was cared for Interventions for arterial occlusive and aneurysmal disease have been aggressively embraced by cardiologists and vascular surgeons It seems that everyone is now interested in image-guided interventions What does this mean? First of all: Success! Interventional procedures are now mainstream and legitimized Second: Excitement! There are no limits to our innovation and therapeutic horizons Third: Change! Interventional radiologists can no longer wait for someone else to decide which procedure to order and when but must see patients in offices or clinics, render consultations, recommend a course of action, perform the procedure, and provide follow-up Lastly: Challenge! If only for the benefit of patients, interventional radiology must mature into the core specialty for all minimally invasive practitioners, with the basic and clinical research to support the procedures and standards that ensure safe and effective care Volume II of THE REQUISITES provides more up-to-date information for this exciting specialty We have endeavored to make it accessible enough for residents but detailed enough to be used by fellows and those seeking a current overview The format is designed to allow quick reference for technical or diagnostic questions but also to provide detailed and focused information The images have been carefully selected to be representative of current practice, with the use of cross-sectional techniques whenever possible When the book started, the authors were colleagues at the Massachusetts General Hospital, one in the Division of Vascular Radiology (Kaufman), the other in the Division of Abdominal Imaging and Intervention (Lee) Today we are international co-conspirators, so that the book reflects a global perspective To sum it all up, we think interventional radiology is great, this is how we it, and we hope you enjoy this book John A Kaufman, MD, MS, FSIR, FCIRSE Michael J Lee, MSc, FRCPI, FRCR, FFR(RCSI), FSIR, EBIR xi Acknowledgments When James Thrall invited me to write this book, I was simultaneously ecstatic and terrified As a junior faculty member in his department at the Massachusetts General Hospital, the invitation was an immense honor, but I had no idea how or when I would it After a while (well, after a few years), Jim was probably thinking the same thing Fortunately for me, Jim has been the most patient mentor, counselor, guide, and friend that I could have ever wished for Without his unflagging support, I could not have done this One of my first steps was to ask Mick Lee to collaborate on the book (read “share the pain”) Fortunately, he agreed Mick is a superb interventionalist, great guy, and, to my chagrin, a much more efficient writer than I am Without him the book would not be I am proud that I can link my name with his on the cover Accomplishments, such as a book, mirror the people in our lives I am a radiologist because I followed the example of someone much smarter than I, my father, Sy Kaufman During my first year of residency, I rotated on “Specials” with Alan Greenfield and John Guben As the cliché goes, I never looked back In July of 1991, after my fellowship with Alan, Jim Parker, and another long-time friend Mike Bettmann, I joined the Division of Vascular Radiology at MGH Arthur Waltman welcomed me into a dream job, a professional family, and the most formative experience of my career Over the next years I learned from an outstanding group of colleagues, including Chris Athanasoulis (whose 1982 textbook Interventional Radiology greatly influenced this book), Chieh-Min Fan, Mark Rieumont, Kent Yucel, and Mitch Rivitz Above all, I worked with Stuart Geller I have never learned so much from one person, ever Stuart, I have tried to put all of it in here; I hope that I have it right In July 2000, I joined Fred Keller, Josef Rösch, Bryan Petersen, Rob Barton, Torre Andrews, Paul Lakin, Ken Kolbeck, Khashayar Farsad, Gary Nesbit, Stan Barnwell, and Dusan Pavcnik at the Dotter Institute in Portland, Oregon Once again I found myself learning from, inspired by, and supported by superb interventionalists, innovators, and people The majority of the images in this book are from the Dotter Institute and were created by these special colleagues Over the years I have been fortunate to spend time with a large number of delightful fellows and residents They don’t know it, but they are the real reason for staying in academics They have all been incredibly generous and reliable when answering my pleas for images, especially Barry Stein in Hartford, Connecticut, and Constantino (“Tino”) Pena in Miami, Florida One of my fellows from the Dotter Institute, Peter Bromley, created many excellent original line drawings in this book Sheri Imai-Swiggart at the Dotter Institute toiled over the images for the first edition of this book for years Special thanks to Bobby Hill for many of the CT reconstructions, including the cover, in this edition This project has taken so long that it has outlasted several generations of Elsevier editors and production staff Stephanie Donley, Mia Cariño, Elizabeth Corra, Hilarie Surrena, and Christy Bracken all graciously brought the first edition to life Margaret Nelson, Sabina Borza, Stacey Fisher, Martha Limbach, and Rebecca Gaertner patiently and persistently made the second edition a reality An author’s family sees a different side of the process This book was time together lost, both in person and in mind The end product has little bearing on the real stuff of family life Yet each and every one supported and encouraged me Cathy, my wife, learned very quickly that this book doubled her work as a parent, which she undertook with characteristic enthusiasm She has been the co-author of my life since I was 18-years-old My daughter Claire Kaufman and son-in-law Keith Quencer, my two favorite radiology residents in the world, were incredible proofreaders for this second edition My two boys, Nick and Alex; mother; and inlaws all saw “the book” as yet another work-related obsession and adjusted accordingly Even the dogs were nice about it Thanks to you all J.A.K My journey in Interventional Radiology began in 1989 when I started a Fellowship in Abdominal Imaging and Interventional Radiology at Massachusetts General Hospital Fresh from my radiology residency in Ireland, I was not sure what to expect The teaching and professionalism of the staff at MGH soon dispelled my uncertainty In particular, I would like to thank Peter Mueller, Nick Papanicolau, Steve Dawson, and Peter Hahn for imparting a wealth of wisdom and experience regarding all things interventional As a fellow, one of the most satisfying achievements is to complete a technically difficult or challenging procedure without a staff supervisor taking over I am sure it was difficult at times but thank you for not “taking over.” I believe that interventional radiologists should have a firm grasp of imaging to make correct therapeutic decisions for their patients During my years at MGH, I was fortunate to learn from some of the great imagers: Joe Ferucci, Jack Wittenberg, Joe Simeone, and Sanjay Saini to name but a few I would like to take this opportunity to especially thank Peter Mueller for his encouragement and support, both clinically and academically during my MGH years Peter was a great mentor and continues to be a good friend Jim Thrall, Chairman of Radiology at MGH, allowed us the freedom to develop clinical and academic skills but also fostered leadership talents This was accomplished with minimal fuss but occasional gentle nudging in a certain direction When John Kaufman asked me to co-author the first edition of this book, I was leaving MGH to take up a Chair in Radiology at the Medical School of the Royal College of Surgeons in Ireland, attached to Beaumont Hospital, Dublin (I have now been in this position for 17 years) I was delighted to accept, knowing that John is a great writer, interventionalist, and good friend The first edition was duly completed and no sooner published when the idea of a second edition surfaced After the many hours spent writing the first edition, the thought of a second edition took a while to flame in my mind However, as time went by, the toil involved in writing the first edition faded and enthusiasm for the second edition increased So here we are with the second edition It was again a mammoth task and took much longer as John and I were both very busy with many other endeavors in the IR world John has been President of SIR during the period of this project and I have been President of CIRSE I commissioned chapters from Niamh Hambly, Afshin Gangi and colleagues, Bill Mayo-Smith, Debbie Gervais, and Damian Dupuy and would like to thank them for their superb efforts I would like to thank Sarah Taylor, Jill Kavanagh, and Gail O’Brien for their expert typing and organizational skills, and all the staff at Elsevier who have patiently reminded us over the years that these books needed to be completed These xiii xiv Acknowledgments include Stephanie Donley, Elizabeth Corra, Mia Cariño, Christy Bracken, and Hilarie Surrena for Volume I; and Margaret Nelson, Sabina Borza, Stacey Fisher, Martha Limbach, and Rebecca Gaertner for Volume II Finally, and most importantly, I would like to thank my wife Eileen for her unwavering support Family, interventional radiology, and academic radiology are a difficult combination to balance Writing a book, in addition to the latter, shifts the balance considerably I could not have written this book without Eileen’s support and understanding Interventional radiology is a fantastically rewarding specialty for those of us fortunate enough to practice it I sincerely hope that Volume II of THE REQUISITES in interventional radiology contributes to the safe practice of our specialty, and I hope that it helps you, the reader, in your IR practice M.J.L Chapter Vascular Pathology John A Kaufman, MD, MS, FSIR, FCIRSE THE NORMAL VASCULAR WALL NEOPLASMS IMPINGEMENT SYNDROMES ATHEROSCLEROSIS DISSECTION ADVENTITIAL CYSTIC DISEASE INTIMAL HYPERPLASIA TRAUMA MÖNCKEBERG SCLEROSIS ANEURYSMS VASOSPASTIC DISORDERS THROMBOSIS FIBROMUSCULAR DYSPLASIA ARTERIAL EMBOLISM VASCULITIS INFECTION HEMANGIOMAS, VASCULAR MALFORMATIONS, AND ARTERIOVENOUS FISTULAS INHERITED DISORDERS OF THE ARTERIAL WALL Blood vessels are, in the simplest of terms, the plumbing of the body Problems arise when blood flow is diminished, excessive, in the wrong direction, or when leaks occur (Table 1-1) In reality, blood vessels are complex organs within other complex organs The degree of vascular disease that can be tolerated before symptoms occur varies with the type of blood vessel, the nature and metabolic state of the perfused organ, and the patient Just as vascular disease can affect an organ, disease in an organ can affect its blood vessels Often, vascular pathology can result in loss of limb, organ, or life The ubiquitous and serious nature of vascular disease makes this a fascinating clinical area This chapter reviews the basic types of pathology that can occur in blood vessels The clinical presentation, diagnosis, and therapy of disease in a particular vascular bed or organ are addressed in specific chapters THE NORMAL VASCULAR WALL The walls of arteries have three layers: the intima, media, and adventitia (Fig 1-1) The intima forms the interface between the artery and the blood Composed of endothelial cells, fibroblasts, and connective tissue, this is the site of much arterial pathology The intima is a dynamic, hormonally active layer that responds to acute stress by release of substances such as prostaglandins and platelet activating factors Chronic stress, such as turbulence, induces proliferation of the endothelial cells and fibroblasts Any object in prolonged contact with the intima eventually becomes coated with a layer of new endothelial cells (neointima) In some circumstances, this proliferation results in local obstructive phenomena The intima therefore has a central role in the natural history of vascular diseases and the outcome of vascular interventions The muscular media is sandwiched between and distinct from the intima and adventitia This layer provides both structural support for the arterial wall as well as the ability to react acutely to sudden hemodynamic changes The media is made up of wellordered layers of elastic fibers, smooth muscle cells, and connective tissue Smooth muscle cells are orientated in both concentric and longitudinal directions The normal arterial media is elastic, dilating slightly with each systole and then recoiling during diastole This is most pronounced in medium and large muscular arteries, and assists in the circulation of blood through the arterial system In response to demands for increased blood flow the smooth muscle cells relax, resulting in enlargement of the vessel lumen (vasodilatation) Conversely, to restrict blood flow, the muscle cells contract to decrease the diameter of the lumen (vasoconstriction) With aging and certain pathologic conditions (e.g., atherosclerosis), the media loses this elasticity and responsiveness as the smooth muscle cells are replaced by fibrotic tissue or become disorganized In fact, large atherosclerotic intimal plaques can actually invade the media The media is also the site of expression of heritable connective tissue disorders such as Marfan syndrome and Ehlers-Danlos syndrome The adventitia is a tough yet filmy layer of connective tissue that forms the boundary between the artery and the surrounding structures This layer contains collagen, fibroblasts, and some smooth muscle cells Weaving through the interface of the adventitia and media are the small vascular channels (the vasa vasorum) that supply blood to capillaries within the adventitia and the outer third of the media The inner part of the media and the intima receive nutrients from the blood in the vessel lumen by diffusion The density of the vasa vasorum is highest in the thickest, most muscular portions of the arteries, such as the ascending and transverse aorta The adventitia also contains the adrenergic nerves (nervi vascularis) that control vasoconstriction and dilatation Veins also have walls with three layers, similarly termed the intima, media, and adventitia Venous and arterial intima and adventitia are similar in composition and function The venous intima rarely undergoes the pathologic changes seen in arteries, unless the vein is exposed to arterial pressures, high flow rates, or foreign bodies for long periods of time Fibrointimal hyperplasia in response to trauma, implantation of endoluminal devices, and increased flow is common This feature of the venous intimal surface is a major determinant of the long-term outcome of many venous vascular interventions The medial layer of veins contains fewer smooth muscle cells than arteries, thus accounting for the relatively thinner, flaccid appearance of the walls In addition, the connective tissue component of the venous media is less pronounced than that of arteries As a result, veins contribute capacitance to the circulation Blood return is facilitated by unidirectional bicuspid valves in the small to medium-sized veins that permit flow only toward the heart Blood flow is maintained by a combination of processes, including gravity, external compression by muscle contraction, and pressure gradients created during inspiration and expiration The smooth muscle cells of the small to medium veins can dilate and contract in response to stimuli, thus partially regulating flow 272 Vascular and Interventional Radiology: The Requisites Box 12-4. Indications for Intervention in Renal Artery Stenosis A Severe hypertension* with: Unilateral or bilateral renal artery stenosis Mean pressure gradient >10 mm Hg or peak systolic gradient > 20 mm Hg Atherosclerosis, fibromuscular dysplasia, Takayasu disease, dissection Renal failure with: No other explanation for severe azotemia Bilateral stenosis† Mean pressure gradient >10 mm Hg or peak systolic gradient > 20 mm Hg Atherosclerosis, dissection *See Box 12-3 for signs of hypertension likely due to renal artery disease †Unilateral renal artery stenosis is unlikely to cause renal failure when the contralateral kidney is normal Box 12-5. Surgical Approaches for Renal Artery Stenosis B Figure 12-15. Delayed opacification of renal artery distal to an occluded stent A, Digital subtraction angiogram of the aorta shows the stump of the occluded left renal artery (arrow) B, Late image from the same injection shows the distal renal artery reconstituted (arrow) through small retroperitoneal branches and induce a pressure gradient Low-profile pressure-sensing guidewires may be useful in this situation Borderline gradients require careful assessment before treatment, including close correlation with the patient’s clinical presentation Sampling of the renin directly from the renal veins is occasionally helpful to establish the diagnosis of renal vascular hypertension and identify which kidney is responsible A curved selective catheter (e.g., Cobra-2) or a straight catheter with a tip deflecting wire can be used A single side hole should be punched near the tip of the catheter Blood samples are obtained from each renal vein, and from the IVC above and below the renal veins On the left, the catheter tip should be lateral to the orifice of the left gonadal vein Samples need not be simultaneous, but they should be collected within a short period of time Renin levels from one kidney that are at least 1.5 times that of the contralateral kidney are indicative of renovascular hypertension A rise in renin between the infrarenal and suprarenal IVC is further evidence of renovascular hypertension When multiple renal veins are present, samples should be obtained from each vein The indications for intervention in renal artery stenosis differ slightly for hypertension and ischemic nephropathy (Box 12-4) All symptomatic lesions that cannot be managed medically require intervention in patients with reasonable life expectancies Asymptomatic lesions are generally not treated unless the kidney is solitary There are numerous surgical options for revascularization of the renal arteries (Box 12-5) Ostial and proximal atherosclerotic renal artery lesions are easier to deal with than distal main or segmental artery lesions The overall mortality for surgical intervention is approximately 4%, with hypertension cured in 18%, improved in 71%, and unchanged or worse in 11% In patients with renal failure, improvement can be expected in 50% of patients, no change is seen in 39%, and in 11%, the condition deteriorates Aortorenal bypass Hepatorenal bypass (right kidney) Splenorenal bypass (left kidney) Aortorenal endarterectomy Ileorenal bypass Autotransplantation to pelvis Nephrectomy Angioplasty and stent placement are the techniques used most often in treatment of obstructive lesions of the renal artery Atherosclerotic lesions are almost always managed with a stent, whereas FMD almost always responds to angioplasty alone These procedures should be approached in a careful, planned manner, as they can be among the most difficult arterial interventions Patients scheduled for renal artery intervention for hypertension should stop or decrease long-acting antihypertensive medications before the procedure if possible Successful angioplasty or stent placement may lead to profound hypotension when drug effects persist after acute renal revascularization Patients should be instructed to drink fluids until hours before the procedure, at which time intravenous fluids should be initiated at a brisk pace Some interventionalists administer a calcium-channel blocking agent before the procedure to prevent vasospasm Patients with preexisting renal failure can be treated beforehand with a renal protective strategy (see Table 2-7) An aortogram should be obtained in all cases; CO2 gas can be used in patients with azotemia Once the decision to intervene is made, syringes containing heparin (1000 U/mL) and nitroglycerin (100 μg/mL) are placed on the angiography table A long curved 6- or 7-French sheath, or a 7- or 8-French curved guiding catheter, is inserted The curve of the sheath or guide catheter is selected to match the angle of the renal artery as it arises from the aorta (see Fig 2-18) Manipulation in the aorta should be minimized to decrease the risk of cholesterol embolization Heparin (5000-10,000 units) is administered before selecting the renal artery For ostial lesions, the image intensifier is angled to display the renal artery ostium in profile A selective 5-French catheter appropriate for the configuration of the renal artery is used to find the renal artery origin A gentle puff of contrast confirms catheter position Ostial lesions are gently probed with an atraumatic but steerable guidewire Extremely tight ostial lesions can sometimes only be crossed with microwires When using a pull-down catheter, leading with 1-2 cm of a Bentson guidewire minimizes the risk of subintimal dissection Renal Arteries 273 Figure 12-16. Guidewire straightening A B Once the selective guidewire has crossed the lesion, the catheter is advanced until it, too, has crossed the lesion The guidewire is removed, blood is aspirated, and a small amount of contrast is injected, followed by 100-200 μg of nitroglycerin When there is complete stasis of the intrarenal branches due to obturation of the lesion by the catheter, additional heparin can be delivered directly into the renal artery A working wire is then carefully inserted A moderately stiff 0.035-inch guidewire with a short straight floppy tip, or 0.014-0.018-inch stiff guidewires with short soft platinum tips are preferred by the author J-tipped guidewires are more likely to induce spasm or cause dissection of intrarenal branches A stiff guidewire can change the angle of the renal artery, facilitating the procedure (Fig 12-16) Careful control of guidewires at all times is critical, because straight-tipped guidewires can perforate the kidney Embolic protective devices can be used in patients with suitable anatomy and lesions (see Fig 4-19) A dedicated renal artery protection device is not currently available The evidence supporting the benefit of renal protection is evolving at this point, but enthusiasm is great The guiding catheter or sheath should be brought as close as possible to the renal artery ostium to provide added stability to the system In addition, contrast can be injected through the sheath or guiding catheter to monitor the progress of the procedure (see Figs 12-14 and 12-16) Ostial lesions almost always require stent placement, because the stenosis is caused by aortic rather than renal artery plaque Predilatation with an undersized balloon facilitates positioning of stents when the lesion is very tight or irregular Stents mounted on 0.018-inch or smaller systems have a low crossing profile and can often be advanced “bare-back” through the lesion Sometimes the sheath or guiding catheter must be advanced through the lesion to facilitate positioning of the stent The ideal stent design for renal artery ostia has not been determined, but most often a balloon-expandable stent is used Whether bare or covered stents provide superior results is unknown Typical diameters for renal artery ostia are 5-7 mm Stent lengths are usually 1.2-2 cm The stent should be deployed so that it protrudes into the aorta a few millimeters to ensure adequate displacement of the aortic plaque (Fig 12-17; see also Figs 12-1 and 3-19) “Flaring” the aortic end of the stent with a slightly larger balloon is cosmetically appealing but of unproven benefit of a renal artery during stent placement A, Control digital subtraction angiogram (DSA) obtained through the sheath (curved arrow) while positioning a balloon-mounted stent (arrow) across the ostial renal artery stenosis A Rosen guidewire is in the posterior division (arrowhead) B, DSA after stent deployment and removal of the guidewire Note the change in angle of the main renal artery (arrow) relative to the aorta compared to the previous image Figure 12-17. Proper and improper stent positioning Digital subtrac- tion angiogram after bilateral renal artery stent placement shows excellent position on the left with slight protrusion into the aortic lumen (arrow) The stent on the right ends within the renal artery (arrowhead) To completely cover the lesion, this stent should also extend to the aortic lumen Proximal renal artery atherosclerotic lesions (i.e., those that are located more than cm from the aortic lumen) respond well to angioplasty alone, but in practice are now routinely stented All of the same precautions described for intervention in ostial lesions should be exercised A large branch in the vicinity of the stenosis can be protected by placing a 0.018-inch guidewire through the sheath or guiding catheter alongside the working wire and into the branch during the angioplasty When the lesion occurs at a bifurcation of the renal artery, kissing balloons or stents may be necessary (Fig 12-18) Drug-eluting stents can be used when treating smaller (≤3.5 mm) renal arteries such as accessory or segmental arteries Data supporting this practice have yet to be developed, but bare stents in renal arteries less than mm in diameter have poor long-term patency Renal artery FMD of the medial fibroplasia type responds well to simple angioplasty with excellent long-term results (see Fig 12-12) Best results occur in patients younger than 50 years of age with duration of hypertension less than years and no evidence of 274 Vascular and Interventional Radiology: The Requisites Figure 12-18. Early bifurcation of the left main renal artery with a proximal stenosis of the lower branch in a young patient with hypertension A, Digital subtraction aortogram before angioplasty showing the proximal renal artery stenosis (arrow) that begins at the bifurcation of the renal artery B, Aortic injection after angioplasty of the stenosis using the kissing technique (a small protective balloon in the upper artery and a 5-mm diameter balloon in the lower artery) showing the placement of the guidewires (arrows) A B Table 12-3 Complications of Renal Artery Angioplasty and Stents Complication Incidence (%) Death (30 days) 0.5 Renal artery rupture 10 cm T2b Tumor extends beyond capsule or into ipsilateral adrenal gland but still within Gerota fascia T3 Extends into renal vein or renal sinus fat T3a Extends into renal vein and IVC below diaphragm T3b Extends into renal vein and IVC above diaphragm T3c Lymph node involvement No regional lymph nodes N0 Metastasis to regional lymph nodes N1 Metastases None M0 Distant M1 T, Tumor stage; N, lymph node stage; M, metastases stage Metanephric Adenoma Metanephric adenomas are rare lesions, found more commonly in women than men (2.6:1) and usually in middle age, although lesions can also occur in children The lesions are most often single, less than cm, symptomatic with pain or hematuria in about one third of cases, and associated with polycythemia vera Diagnosis is almost always by CT or MRI, and management is with a renal tissue-sparing resection T, Tumor stage; N, lymph node stage; M, metastases stage See Table 12-7 for definition of TNM stages Renal Cell Carcinoma RCC is increasing in frequency (about 65,000 new cases are diagnosed in the United States each year), but the average size at diagnosis is getting smaller and survival is improving The majority of cases are now discovered incidentally during imaging for other reasons In adults, RCCs comprise over 80% of all malignant renal masses, with transitional cell carcinoma of the renal pelvis (8%-10%), nephroblastoma (Wilms tumor, 5%-6%), and miscellaneous sarcomas (2%-3%) accounting for the remainder RCCs are more common in males than females, may be multiple when associated with von Hippel-Lindau disease, and are typically found in patients 40 years or older More than 90% of RCCs are epithelial in origin, of which 75% are clear cell, 15% papillary, and 5% chromophobe carcinoma A grading system has been developed to describe RCCs (Fig 12-28; Tables 12-7 and 12-8) At presentation, about 60% are localized, 20% have regional lymph node involvement, and 20% have distant metastases Survival with localized disease is 70% at years and is very dependent upon the histologic features of the tumor Tumor invasion of the renal vein or IVC in the absence of metastasis has a 5-year survival rate of approximately 50% in patients undergoing radical nephrectomy with complete removal of IVC thrombus Renal Arteries 281 A B C Figure 12-29. Alcohol ablation of the left kidney in a patient with a large renal cell carcinoma A, Selective left renal angiogram shows hypervascularity and neovascularity replacing the entire left kidney B, An occlusion balloon (arrow) has been inflated in the renal artery distal to the inferior adrenal artery A total of mL of dehydrated alcohol was infused C, Aortogram after embolization showing the absence of flow in the left renal artery (arrow) The treatment options for small RCC include percutaneous ablation (see Chapter 25) and laparoscopic partial nephrectomy Catheter-based interventions are reserved for large lesions before resection or as palliative treatment The typical indication for angiographic intervention in RCC is preoperative embolization of the tumor (see Fig 12-28) Large renal cell cancers and those with venous invasion can be difficult to resect owing to the extremely vascular nature of the mass In these cases, embolization of the entire kidney before resection can reduce blood loss significantly The timing for embolization varies from one center to another, but is generally performed within 24 hours of the surgery Embolization 4-6 weeks in advance was once advocated because of theoretical induction of an autoimmune response, but that protocol is now rarely practiced The goal of embolization is devascularization of the tumor and usually the kidney For this reason, peripheral embolization is preferred Dehydrated alcohol, small particles or spheres, Gelfoam powder, or Gelfoam pledgets can be used The choice of particle size should be based on the presence of arteriovenous shunts Smaller particles result in a longer procedure but a more peripheral embolization Alcohol ablation using a balloon occlusion catheter for control in the main renal artery is favored by many interventionalists (Fig 12-29) The volume of absolute alcohol required depends on the size and vascularity of the mass (see Chapter 4, Box 4-21) At the termination of the embolization, a few coils may be placed deep in the main renal artery Coils placed in the proximal renal artery can be displaced into the aorta during surgical manipulation of the kidney If coils are placed, the surgeon should be alerted to their presence Wilms Tumor Wilms tumor is primarily a childhood lesion (8/1,000,000 children younger than 15 years of age), although there is a second peak incidence in the sixth decade In children, the 5-year survival is 90% with lower stage tumors; in adults, 5-year survival is approximately 80% Treatment includes resection, chemotherapy, and radiation therapy Box 12-9. Vascular Imaging Goals for Renal Donors Number of renal arteries Length of main renal arteries (preferred > cm) Quality of renal artery (presence of atherosclerosis or other pathology) Renal vein anatomy Quality of aorta Metastatic Disease Metastases to the kidney are seen in about 1% of all nonrenal cancers The most common primary is lung carcinoma, with breast, gastrointestinal, and melanoma being the next most likely tumors of origin Usually tumor involvement is bilateral and multiple, such that synchronous RCC is not a concern Rarely metastases are single and isolated to the kidney, in which case clinical and imaging differentiation from primary RCC is difficult In these cases, percutaneous ablation or surgical resection should be considered because survival is improved with treatment in the absence of other metastatic disease RENAL TRANSPLANTATION Evaluation of the renal vasculature is an essential component of the workup of living donors and is frequently required when a transplanted kidney malfunctions or fails The objectives of vascular imaging are different in each group Vascular interventions are usually only necessary following transplantation The imaging of living renal donors is focused on detection of exclusionary vascular and parenchymal abnormalities or anomalies (Box 12-9) The left kidney is preferred by most surgeons because of the longer renal vein In the past, when only open nephrectomy was performed, interest in the arterial anatomy was far greater than the renal veins However, with laparoscopic donor nephrectomy, information about renal vein anatomy is of great importance Most centers rely heavily on CT/CTA or MR/MRA, as these modalities 282 Vascular and Interventional Radiology: The Requisites Table 12-9 Vascular Complications of Renal Transplantation Complication Incidence (%) Renal artery stenosis 5-10 Renal artery thrombosis 1-2 Renal vein thrombosis 1-2 Postbiopsy pseudoaneurysm 1-2 Postbiopsy arteriovenous fistula 1-2 Anastomotic pseudoaneurysm