Vascular Surgery - part 1 ppt

EUGENE STRANDNESS, JR., MD, DMED Former Professor of Surgery University of Washington Former Attending Surgeon University of Washington Medical Center Seattle, Washington JONATHAN B.TOWN

Haimovici's Vascular Surgery

5th edition

As I assume chief editorship with this edition of Haimovici's Vascular Surgery,

I would like to take this opportunity to recognize my parents, Samuel and Emilia,for their guidance and support throughout my life

Enrico Ascher

FIFTH EDITION

Editor-in-Chief Enrico Ascher

Associate Editors

LH.Hollier D.Eugene Strandness Jonathan B.Towne

Co-editors Keith Calligaro K.Craig Kent Gregory L Moneta William H Pearce JohnJ.Ricotta

Founding Editor Henry Haimovici

Blackwell

Publishing

04 05 06 07 5 4 3 2 1

ISBN: 0-632-04458-6

Library of Congress Cataloging-in-Publication Data

Haimovici's vascular surgery -5th ed / editor-in-chief, Enrico Ascher; associate editors,

LH Hollier, D Eugene Strandness, Jr., Jonathan B Towne; co-editors, Keith Calligaro let al.l; founding editor, Henry Haimovici.

p.; cm

includes index.

ISBN 0-632-04458-6 (hardcover)

1 Blood-vessels-Surgery.

[DNLM:1 Vascular Surgical Procedures WG170 H1512004] I Title: vascular surgery.

II Ascher, Enrico III Haimovici, Henry,

1907-RD598.5.V392004

617.4'13-dC21

2003011854

A catalogue record for this title is available from the British Library

Acquisitions: Laura DeYoung

Development: Julia Casson

Production: Julie Elliott and DebraLally

Cover design: Hannus Design Associates

Typesetter: SNP Best-set Typesetter Ltd., Hong Kong

Printed and bound by Sheridan Books, Ann Arbor, Ml

For further information on Blackwell Publishing, visit our website:

www.blackwellpublishing.com

Notice: The indications and dosages of all drugs in this book have been recommended

in the medical literature and conform to the practices of the general community The medications described do not necessarily have specific approval by the Food and Drug Administration for use in the diseases and dosages for which they are recommended The package insert for each drug should be consulted for use and dosage as approved by the FDA Because standards for usage change, it is advisable to keep abreast of revised recommendations, particularly those concerning new drugs.

A Tribute to Henry Haimovici,

Frank J veith and Enrico Ascher

Duplex Arteriography for Lower Extremity 35

Revascularization, Enrico Ascher and

Computed Tomography in Vascular s?

Disease, Frederick L Hoff, Kyle Mueller, and

William Pearce

CHAPTER 7

Magnetic Resonance Angiography, 103

Jagajan J Karmacharya, Omaida C Velazquez,

Richard A Baum, and Jeffrey P Carpenter

PART II Basic Cardiovascular Problems

CHAPTER 8Hemodynamlcs of Vascular Disease: n?Applications to Diagnosis and Treatment,

David S Sumner

CHAPTER 9Artherosclerosis: Biological and Surgical 137 Considerations, Bauer E.sumpio

CHAPTER 10Intimal Hyperplasia, ChristopherK.zarins, 164 Chengpei Xu, Hisham S Bassiouny, and

Seymour Clagov

CHAPTER 11Therapeutic Angiogenesis, K.craigKent i?e

CHAPTER 12Thrombogenesis and Thrombolysis, 183Donald Silver, Leila Mureebe, and Thomas A Shuster

CHAPTER 13Etiology of Abdominal Aortic Aneurysm, 196Ahmad R Bhatti, Tonya P Jordan, and M David Tilson

CHAPTER 14Cardiopulmonary Assessment for Major 205 vascular Reconstructive Procedures,

John D Bisognano, Thomas w Wakefield, and James C.Stanley

PART III Basic Vascular and Endovascular Techniques

CHAPTER 15Vascular Sutures and Anastomoses,Henry Haimovici

221

Balloon Angioplasty of Peripheral Arteries 247

and Veins, Juan Ayerdi, Maurice M Solis, and

Kim J.Hodgson

CHAPTER 19

Stents for Peripheral Arteries and Veins, 257

Carber C Huang and Samuel S Ann

CHAPTER 20

Thrombolytic Therapy for Peripheral 272

Arterial and venous Thrombosis,

w Todd Bohannon and Michael B Silver, Jr

CHAPTER 21

Role of Angioplasty in Vascular Surgery, 285

Arnold Miller and Charles P Panisyn

The Vertebrobasilar System: Anatomy and 304

Surgical Exposure, Ronald A Kline and

Trans-sternal Exposure of the Great vessels 315

Of the Aortic Arch, Calvin B Ernst

CHAPTER 26

The Upper Extremity, Henry Haimovici 322

CHAPTER 27

Transperitoneal Exposure of the Abdominal 334

Aorta and Iliac Arteries, Henry Haimovici

CHAPTER 28

Retroperitoneal Exposure of the

Abdominal Aorta, Calvin B Ernst

Robertw.Hobson.il

CHAPTER 32Arterial Embolism of the Extremities and 388Technique Of EmbOlectomy, Henry Haimovici

CHAPTER 33

Fluoroscopically Assisted 409 Thromboembolectomy, Evan c upsitz,

Frank J veith, and Takao Ohki

CHAPTER 34

Percutaneous Aspiration 417 Thromboembolectomy, Rodney A white

CHAPTER 35 Vascular Trauma, AsherHirshbergand 421

CHAPTER 38Arteriographic Patterns of Atherosclerotic 453 Occlusive Disease of the Lower Extremity,

Henry Haimovici

CHAPTER 39

Nonatherosclerotic Diseases of Small 475

Arteries, Henry Haimovici and Yoshio Mishima

CHAPTER 40

Aortoiliac, Aortofemoral, and lliofemoral 499

Arteriosclerotic Occlusive Diseases,

David C Brewster

CHAPTER 41

Percutaneous Interventions for Aortoiliac 522

OCClUSive Disease, Edward B Dietnrich

CHAPTER 42

Femoropopliteal Arteriosclerotic Occlusive 534

Disease: Operative Treatment, Frank j.veitn

and Henry Haimovici

CHAPTER 43

in Situ vein Bypass by Standard Surgical 559

Technique, DhirajM.Shah.R Clement Darling, III,

Benjamin B Chang, Paul B Kreienberg, Philip S.K Paty,

Sean P Roddy, Kathleen J ozsvath, and Manish Mehta

CHAPTER 44

Small-artery Bypasses to the Tibial and BBS

Peroneal Arteries for Limb Salvage,

Frank J Veith, Sushil K Gupta, Evan C Lipsitz,

and Enrico Ascher

CHAPTER 45

Bypasses to the Plantar Arteries and Other 582

Branches Of Tibial Arteries, Enrico Ascherand

William R.Yorkovich

CHAPTER 46

Extended Techniques for Limb Salvage 587

Using Free Flaps, David L Feldman and L

Scott Levin

CHAPTER 47

Extended Techniques for Limb Salvage 592

Using Complementary Fistulas, Combined

with Deep vein interposition, Enrico Ascher

CHAPTER 48

Extended Techniques for Limb Salvage eoo

Using Vein Cuffs and Patches, Robyn Macsata,

Richard F Neville, and Anton N Sidawy

CHAPTER 49

intraoperative Assessment of Vascular eoe

Reconstruction, Jonathan B.Towne

Endovascular Repair of Abdominal Aortic 735

Aneurysms, Juan C Parodi and Luis M Ferreira

Vlll Contents

CHAPTER 61

Endovascular Treatment of Ruptured

Inf rarenal Aortic and iliac Aneurysms,

Frank J Veith and Takao Ohki

Endovascular Grafts in the Treatment of 767

Isolated Iliac Aneurysms, Frank j.veith,

Evan C Lipsitzjakao Ohki, William D Suggs,

Jacob Cynamon, and Alia M Rozenblit

CHAPTER 65

Para-anastomotic Aortic Aneurysms: 775

General Considerations and Techniques,

Daniel J Char and John J Ricotta

PART Vlll

Cerebrovascular insufficiency

CHAPTER 66

Carotid Endarterectomy: indications 737

and Techniques for Carotid Surgery,

Anthony M Imparato

CHAPTER 67

Eversion Carotid Endarterectomy, sio

R Clement Darling, ill, Manish Mehta, Philip S K Paty,

Kathleen J ozsvath, Sean P Roddy, Paul B Kreienberg,

Benjamin B Chang, and Dhiraj M Shah

CHAPTER 68

Complications and Results in Carotid si?

Surgery, Michael S.conners, III and

Samuel R Money

CHAPTER 69

Carotid Stenting: Current Status and 827

Clinical update, Robert w Hobson, ii

CHAPTER 70

Vertebrobasiiar Disease: Surgical 335

Management, Ronald A Kline and

Ramon Berguer

PART IX Visceral vessels

CHAPTER 72 Surgery of Celiac and Mesenteric Arteries, setStephen P Murray, Tammy K Ramos, and

Ronald J.Stoney

CHAPTER 73 Mesenteric ischemia, juiieA.Freischiag, 375Michael M Farooq, and Jonathan B Towne

CHAPTER 74 Renal Artery Revascularization, 887Keith D Calligaroand Matthew J Dougherty

CHAPTER 75 Visceral Artery Aneurysms, Matthew j 902Dougherty and Keith D calligaro

PART X Upper Extremity Conditions

CHAPTER 76 Vasospastic Diseases of the Upper 915Extremity, ScottE Musicant, Gregory L Moneta,

James M Edwards, and Gregory J LandryCHAPTER 77

Neurogenic Thoracic Outlet syndrome, 924Richard J Sanders and Michael A Cooper

CHAPTER 78 Venous Thoracic Outlet syndrome or 940 Subclavian Vein Obstruction,

Richard J Sanders and Michael A Cooper

CHAPTER 79 Arterial Thoracic Outlet syndrome, 949Frank J Veith and Henry Haimovici

CHAPTER 80 Arterial Surgery of the Upper Extremity, 958 James S.T Yao

CHAPTER 81

Upper Thoracic Sympathectomy: 974

Conventional Technique, Henry Haimovici

Arteriovenous Fistulas and Vascular 991

Malformations, PeterCloviczki,AudraA Noel,

and Larry H Hollier

CHAPTER 84

Vascular Access for Dialysis, Harryscnanzer 1015

and Andres Schanzer

CHAPTER 85

Portal Hypertension, JamesD.Easonand 1030

JohnC Bowen

CHAPTER 91Venous Interruption, Lazarj Greenfield and 1097Mary C Proctor

CHAPTER 92Contemporary Venous Thrombectomy, noeAnthony J Comerota

CHAPTER 93Endoscopic Subfascial Ligation of 1115Perforating Veins, ManjuKalraand

Peter Cloviczki

CHAPTER 94Venous Reconstruction in Post- 1131 thrombotic Syndrome, seshadri Raju

CHAPTER 95ischemic venous Thrombosis: Phlegmasia 1139 Cerulea Dolens and venous Gangrene,

Henry Haimovici

CHAPTER 96Diagnosis and Management of 1152Lymphedema, Mark D.lafratiand

Thomas F O'Donnell, Jr

PART XII

Venous and Lymphatic Surgery

CHAPTER 86

Clinical Application of Objective Testing 1047

in Venous Insufficiency, John J Bergan and

Acute Upper Extremity Deep Vein 1091

Thrombosis, Anil Hingorani and Enrico Ascher

PART XIII

Amputations and Rehabilitations

CHAPTER 97

Amputation of the Lower Extremity: 1171 General Considerations, Henry Haimovici

CHAPTER 98Above-the-knee Amputations, 1175Henry Haimovici

CHAPTER 99Postoperative and Preprosthetic 1133 Management for Lower Extremity

Amputations, YeongchiWu

CHAPTER 100Prosthetics for Lower Limb Amputees, 1190 Jan J stokosa

Index 1207

It has been nearly three decades since the late Dr Henry

Haimovici (1907-2001) first presented to us his landmark

publication Vascular Surgery: Principles and Techniques.

Even then he observed that, in this historically brief period

of time, we had already experienced momentous

develop-ments in the magnitude and scope of our specialty I

be-lieve that, unlike any other period of time and unlike any

other surgical specialty, we have also maintained the

abil-ity to focus and redirect our craft in tandem with, if not in

advance of, the changing needs of our patients and the

technological advancements available to us As a great

pi-oneer of vascular surgery, Dr Haimovici was a principal

instrument of our success throughout the infancy and

maturation of vascular surgery He was ever committed to

its future beyond measure Henry was also my mentor and

a great friend I am forever indebted to him for the

privi-lege of assuming editorship of this grand textbook

We are also saddened by the loss of yet another great

leader in vascular surgery: D Eugene Strandness, Jr., MD

(1928-2002) Dr Strandness fielded numerous

contribu-tions throughout the formative years of noninvasive

vas-cular testing and ultimately established what has now

become our most effective asset in the diagnosis of

vascu-lar disease—the vascuvascu-lar laboratory His early work

fo-cused on physiologic tests, but he was also responsible for

the development and application of direct ultrasonic

methods for vascular diagnosis Working with engineers

at the University of Washington, he combined a B-mode

imaging system and a Doppler flow detector to create the

first duplex scanner These explorers of science were lific in their contributions to our specialty through theirresearch, publications, and societal leaderships It is intheir footsteps that the current and successive generations

pro-of vascular leaders must walk—and they have left greatshoes for them to fill

We are proud to have returning Section Editors LarryHollier (Aortic and Peripheral Aneurysms), EugeneStrandness (Imaging Techniques), and Jonathan B Towne(Acute Arterial Occlusions of the Lower Extremities) Weare also fortunate to have joining us K Craig Kent (BasicCardiovascular Problems), John J Ricotta (Cerebrovas-cular Insufficiency), Keith D Calligaro (Visceral Vessels),Gregory L Moneta (Specific Upper Extremity Occlu-sions), and William H Pearce (Venous and LymphaticSurgery) as Section Editors

This 5th edition of Haimovici's Vascular Surgery

remains true to its heritage of the comprehensive tion of the practice of vascular surgery Innovations in op-erative technique and reflections on noninvasivediagnostic imaging have been examined and each topichas been updated and expanded This textbook has nowincluded the most current topics regarding endovasculartherapy Extensive changes have been made to thisedition—fully 75 chapters have been revised and 25 newchapters have been added

inspec-Enrico Ascher, MD New York, New York

2003

all those who have labored to see this important endeavor

come to fruition There are so many worthy contributors

to this edition, including both the prominent leaders of

today and the rising stars of tomorrow, that the author's

index reads like the "Who's Who?" of vascular surgery

Their roles are of great import not only now, but will

extend well into the millennium

Within my own practice, I am grateful to my partner

and friend, Dr Anil Hingorani, for permitting me the

nec-essary "protected time" away from the operating room

and from the clinic when I needed to focus on this project

I also especially wish to recognize my assistant, Ms Anne

Ober, for her perseverance, loyalty, and dedication Her

many personalities involved, when necessary, are alleled and much appreciated

unpar-Lastly, I must thank Blackwell Publishing for theircontinued support of this title Many have contributedtheir talents, but particular recognitions are due to JuliaCasson, Development Editor, and Kate Heinle, EditorialCoordinator Their professional expertise and roles in theevolution of this complex undertaking are amply evident

in the cohesive production that has evolved

Enrico Ascher, MD New York, New York

2003

ENRICO ASCHER.MD

Professor of Surgery

Mount Sinai School of Medicine

New York, New York

Chief, Vascular Surgery Services

Maimonides Medical Center

Brooklyn, New York

L H HOLLIER, MD, FACS, FACC, FRCS (ENC)

Julius Jacobson Professor of Vascular Surgery

Mount Sinai School of Medicine

President

The Mount Sinai Hospital

New York, New York

D EUGENE STRANDNESS, JR., MD, DMED

Former Professor of Surgery

University of Washington

Former Attending Surgeon

University of Washington Medical Center

Seattle, Washington

JONATHAN B.TOWNE.MD

Professor of Surgery

Chairman of Vascular Surgery

Medical College of Wisconsin

Milwaukee, Wisconsin

KEITH CALLICARO.MD

Associate Clinical Professor

University of Pennsylvania School of Medicine

Chief, Section of Vascular Surgery

Pennsylvania Hospital

Philadelphia, Pennsylvania

K CRAIG KENT, MD

Chief

Columbia Weill Cornell Division of Vascular Surgery

Columbia College of Physicians and Surgeons

Weill Medical College of Cornell University

New York, New York

GREGORY LMONETA.MD

Professor of Surgery Head, Division of Vascular Surgery Oregon Health and Science University Portland, Oregon

JOHN J RICOTTA, MD, FACS

Professor and Chair Department of Surgery State University of New York at Stony Brook Chief of Surgery

Stony Brook University Hospital Stony Brook, New York

HENRY HAIMOVICI,MD

Former Foreign Corresponding Member French National Academy of Medicine Paris, France

Former Clinical Professor Emeritus of Surgery Albert Einstein College of Medicine at Yeshiva University Former Senior Consultant and

Chief Emeritus of Vascular Surgery Montefiore Medical Center New York, New York

EDITORS

SAMUEL S.AHN,MD,FACS

Clinical Professor of Surgery

UCLA School of Medicine

Attending Surgeon

UCLA Center for the Health Sciences

Division of Vascular Surgery

Los Angeles, California

FRANK R.ARKO.MD

Director, Endovascular Surgery

Assistant Professor of Surgery

Division of Vascular Surgery

Stanford

ENRICO ASCHER.MD

Professor of Surgery

Mount Sinai School of Medicine

New York, New York

Chief, Vascular Surgery Services

Maimonides Medical Center

Brooklyn, New York

JUANAYERDI.MD

Division of Peripheral Vascular Surgery

Southern Illinois University School of Medicine

Springfield, Illinois

HISHAN S BASSIOUNY, MD

Associate Professor of Surgery

Medical Director of Noninvasive Laboratories

Department of Vascular Surgery

Professor and Chief

Division of Vascular Surgery

Wayne State University/Detroit Medical Center

Detroit, Michigan

AHMAD F.BHATTI.MD

Columbia University and St Luke's/

Roosevelt Hospital Center

New York, New York

JOHN D BISOCNANO, MD, PhD, FACP, FACC

Assistant Professor of Medicine

University of Rochester

Attending Cardiologist

Strong Memorial Hospital

Rochester, New York

W TODD BOHANNON, MD

Assistant Professor of Surgery and Radiology Texas Technical University Health Sciences Center University Medical Center

Lubbock, Texas

MAURICIOP.BORIC.PhD

Departomento de Ciencias Fisiologicas

P Universidad Catolica de Chile Santiago, Chile

Massachusetts General Hospital Boston, Massachusetts

WARNER P BUNDENS, MD

Assistant Clinical Professor of Surgery University of California, San Diego San Diego, California

KEITH D CALLIGARO, MD, FACS

Associate Clinical Professor University of Pennsylvania School of Medicine Chief, Section of Vascular Surgery

Pennsylvania Hospital Philadelphia, Pennsylvania

JEFFREY P CARPENTER, MD

Associate Professor of Surgery Department of Surgery University of Pennsylvania School of Medicine Philadelphia, Pennsylvania

ALFIOCARROCCIO.MD

Resident in Vascular Surgery Division of Vascular Surgery Mount Sinai Medical Center New York, New York

BENJAMIN B CHANG, MD

Assistant Professor of Surgery Albany Medical College Attending Vascular Surgeon Albany Medical Center Hospital Assistant Professor of Surgery Albany, New York

XIV Contributors

G PATRICK CLAGETT.MD

Jan and Bob Pickens Distinguished Professorship in

Medical Science

Professor and Chairman, Division of Vascular Surgery

University of Texas Southwestern Medical Center

Dallas, Texas

ANTHONY J COMEROTA, MD

Professor of Surgery

Temple University School of Medicine

Chief, Vascular Surgery

Temple University Hospital

Philadelphia, Pennsylvania

MICHAELS.CONNERS, III, MD

Vascular Surgery Fellow

Alton Ochsner Clinic Foundation

New Orleans, Louisiana

Chief, Division of Cardiothoracic Surgery

Baylor College of Medicine

Houston, Texas

JACOB CYNAMON.MD

Maimonides Medical Center

Brooklyn, New York

R CLEMENT DARLING, III, MD

Professor of Surgery

Albany Medical College

Chief, Division of Vascular Surgery

Albany Medical Center

Albany, New York

EDWARD B DIETHRICH, MD

Medical Director and Chief of Cardiovascular Surgery

Arizona Heart Institute

Arizona Heart Hospital

Director and Chairman

Department of Cardiovascular Services

Healthwest Regional Medical Center

Phoenix, Arizona

MATTHEW J DOUGHERTY, MD, FACS

Assistant Clinical Professor

Professor of Physiology and Surgery

Chief, Division of Microcirculatory Research

Department of Physiology

University of Medicine and Dentistry of New Jersey

New Jersey Medical School

Newark, New Jersey

JAMES D EASON, MD, FACS

Head, Section of Abdominal Transplantation

Ochsner Clinic Foundation

New Orleans, Louisiana

JAMES M EDWARDS, MD

Associate Professor of Surgery, Division of Vascular Surgery

Oregon Health Sciences University

Chief of Surgery, Portland Veterans Affairs Medical Center Portland, Oregon

CALVIN B ERNST, MD

Clinical Professor of Surgery University of Michigan Medical School Head, Division of Vascular Surgery Henry Ford Hospital

Detroit, Michigan

MICHAEL M.FAROOQ.MD

Assistant Professor of Surgery University of California, Los Angeles

DAVID L FELDMAN, MD, FACS

Assistant Professor of Surgery SUNY Health Science Center at Brooklyn Director, Division of Plastic Surgery Maimonides Medical Center Brooklyn, New York

LUISM.FERREIRA.MD

Staff, Vascular Surgery Department Institute Cardiovascular de Buenos Aires Buenos Aires, Argentina

PETER GLOVICZKI.MD

Professor of Surgery Mayo Medical School Chair, Division of Vascular Surgery Director, Gonda Vascular Center Mayo Clinic and Foundation Rochester, Minnesota

LAZARJ GREENFIELD, MD

Frederick A Collier Professor and Chairman of Surgery University of Michigan Medical School

Department of Surgery University of Michigan Medical Center Ann Arbor, Michigan

SUSHILK GUPTA, MD

Section Chief Guthrie Clinic Sayre, Pennsylvania

HENRY HAIMOVICI.MD

Former Foreign Corresponding Member French National Academy of Medicine Paris, France

Former Clinical Professor Emeritus of Surgery Albert Einstein College of Medicine at Yeshiva University Former Senior Consultant and Chief Emeritus

of Vascular Surgery Montefiore Medical Center New York, New York

ASHERHIRSHBERG.MD

Associate Professor of Surgery Michael E DeBakey Department of Surgery Baylor College of Medicine

Director of Vascular Surgery Medical Director, Non-invasive Vascular Laboratory Ben Taub General Hospital

Houston, Texas

Clinical Assistant Professor

State University of NY—Brooklyn

Attending Surgeon

Maimonides Medical Center

Brooklyn, New York

ROBERTW HOBSON, II, MD

Professor of Surgery and of Physiology

Division of Vascular Surgery

Department of Surgery

University of Medicine and Dentistry of New Jerse

New Jersey Medical School

Newark, New Jersey

Division of Peripheral Vascular Surgery

Southern Illinois University School of Medicine

Springfield, Illinois

L H HOLLIER, MD, FACS, FACC, FRCS (Eng)

Julius Jacobson Professor of Vascular Surgery

Mount Sinai School of Medicine

President

The Mount Sinai Hospital

New York, New York

CAREER C HUANG, MD

Endovascular Fellow, Division of Vascular Surgery

UCLA School of Medicine

Los Angeles, California

MARK D IAFRATI, MD, RVT, FACS

Department of Surgery

Division of Vascular Surgery

New England Medical Center

Boston, Massachusetts

ANTHONY M IMPARATO, MD

Professor of Surgery

New York University School of Medicine

New York, New York

TONYA P JORDAN, MD

Columbia University and St Luke's/Roosevelt Hospital Center

New York, New York

MANJU KALRA, MBBS FRCSEd

Columbia Weill Cornell Division of Vascular Surgery

Columbia College of Physicians and Surgeons

Weill Medical College of Cornell University

New York, New York

SASHI KILARU, MD

Vascular Surgery Fellow

Weill Cornell Medical College

New York Presbyterian Hospital—Cornell New York, New York

PAULB.KREIENBERG.MD

Associate Professor of Surgery Albany Medical College Attending Vascular Surgeon Albany Medical Center Hospital Albany, New York

RONALD A KLINE, MD, FACS

Associate Professor of Surgery Wayne State University School of Medicine Program Director, Vascular Surgery Harper University Hospital Detroit, Michigan

ELKELORENSEN.MD

Vascular Fellow Maimonides Medical Center Brooklyn, New York

JAMES B LYONS, MD

Interventional Radiologist Desert Samaritan Medical Center Mesa, Arizona

P MICHAEL MCFADDEN, MD

Clinical Professor of Surgery Tulane University School of Medicine Surgeon and Surgical Co-Director Lung Transplantation Program Ochsner Clinic

New Orleans, Louisiana

ROBYN MACSATA, MD

Resident, Vascular Surgery Washington Hospital Center Georgetown University Washington, DC

KENNETH L MATTOX, MD

Professor and Vice Chair Michael E DeBakey Department of Surgery Baylor College of Medicine

Chief of Staff/Chief of Surgery Ben Taub General Hospital Houston, Texas

MANISH MEHTA, MD

Assistant Professor of Surgery Albany Medical College Attending Vascular Surgeon Albany Medical Center Hospital Albany, New York

XVI Contributors

ARNOLD MILLER, MD

Associate Clinical Professor of Surgery

Harvard Medical School

Boston, Massachusetts

Chief

Department of Surgery

Leonard Morse Hospital

Metro West Medical Center

Natick, Massachusetts

YOSHIOMISHIMA.MD

Professor and Chairman of Surgery

Tokyo Medical and Dental University

Tokyo, Japan

GREGORY LMONETA.MD

Professor of Surgery

Chief, Division of Vascular Surgery

Oregon Health Sciences University

Portland, Oregon

SAMUEL R MONEY, MD, FACS, MBA

Clinical Associate Professor

Tulane School of Medicine

Head, Section of Vascular Surgery

Ochsner Clinic Foundation

New Orleans, Louisiana

NICHOLAS J MORRISSEY, MD

Assistant Professor of Surgery

Division of Vascular Surgery

Mt Sinai School of Medicine

New York, New York

KYLE MUELLER, MD

Resident, General Surgery

Northwestern University Medical School

Chicago, Illinois

LEILA MUREEBE.MD

Assistant Professor, Department of Surgery

University of Missouri—Columbia

Staff Surgeon, Department of Surgery

University of Missouri Health Care

Columbia, Missouri

STEPHEN P MURRAY, MD

Inland Vascular Institute

Spokane, Washington

Assistant Clinical Professsor, Surgery

Uniformed Services University of the Health Sciences

Division of Vascular Surgery Mayo Clinic

TAKAOOHKI.MD

Associate Professor of Surgery Albert Einstein College of Medicine Chief, Vascular and Endovascular Surgery Montefiore Medical Center

Bronx, New York

KATHLEEN J OZSVATH, MD

Assistant Professor of Surgery Albany Medical College Attending Vascular Surgeon Albany Medical Center Hospital Albany, New York

Newark, New Jersey

PHILIP S K PATY, MD

Associate Professor of Surgery Albany Medical College Attending Vascular Surgeon Albany Medical Center Hospital Albany, New York

JUANC.PARODI.MD

Vice Director of the Post-Graduate Training Program in Cardiovascular Surgery of the University of Buenos Aires Chief, Vascular Surgery Department

Institute Cardiovascular de Buenos Aires Director, Institute Cardiovascular de Buenos Aires Buenos Aires, Argentina

MARY C PROCTOR, MS

Department of Surgery University of Michigan Medical School Ann Arbor, Michigan

TAMMY K RAMOS, MD

Creighton University Medical Center

Department of Surgery

Omaha, Nebraska

SESHADRI RAJU, MD, FACS

Emeritus Professor of Surgery and Honorary Surgeon

University of Mississippi Medical School

Jackson, Mississippi

JOHN J RICOTTA, MD

Professor and Chairman of Surgery

Department of Surgery

Stony Brook University Hospital

Stony Brook, New York

SEAN P RODDY, MD

Assistant Professor of Surgery

Albany Medical College

Attending Vascular Surgeon

Albany Medical Center Hospital

Albany, New York

ALLAM.ROZENBLIT,MD

Maimonides Medical Center

Brooklyn, New York

Clinical Professor of Surgery

University of Colorado School of Medicine

Rose Medical Center

Denver, Colorado

ARMANDO SARDI, MD, FACS

Chief Surgical Oncology

Medical Director, Clinical Research Center

St Agnes HealthCare

Baltimore, Maryland

ANDRES SCHANZER.MD

Surgical Resident, Department of Surgery

University of California at Davis

UCD Medical Center

Sacramento, California

HARRY SCHANZER, MD, FACS

Clinical Professor of Surgery

Mount Sinai School of Medicine

Attending Surgeon

Mount Sinai Hospital

New York, New York

CARYR.SEABROOK.MD

Professor of Vascular Surgery

Medical College of Wisconsin

Milwaukee, Wisconsin

DHIRAJM.SHAH.MD

Director, The Vascular Institute

Professor of Surgery

Associate Professor of Physiology and Cellular Biology

Albany Medical College

Albany, New York

THOMASA.SHUSTER.DO

Vascular Surgery Fellow, Department of Surgery

University of Missouri—Columbia

Vascular Fellow, Department of Surgery

University of Missouri Health Care Columbia, Missouri

ANTON N SIDAWY, MD, MPH

Professor of Surgery George Washington University Georgetown University Chief, Surgery Service

VA Medical Center Washington, DC

MICHAEL B.SILVA, Jr., MD

Vice-Chairman, Department of Surgery Professor & Chief, Vascular Surgery and Vascular Interventional Radiology

Texas Tech University Health Sciences Center Attending Surgeon

University Medical Center Lubbock, Texas

DONALD SILVER, MD

Professor Emeritus, Department of Surgery University of Missouri—Columbia Medical Director, Surgical Services University of Missouri Health Care Columbia, Missouri

MAURICE M SOUS, MD

Chief, Vascular and Endovascular Surgery Macon Cardiovascular Institute and Mercer University School of Medicine

D EUGENE STRANDNESS, Jr., MD, DMed

Former Professor of Surgery University of Washington Former Attending Surgeon University of Washington Medical Center Seattle, Washington

DAVID S.SUMNER,MD

Distinguished Professor of Surgery, Emeritus Chief, Section of Peripheral Vascular Surgery Southern Illinois University School of Medicine Springfield, Illinois

Chief of Vascular Surgery

Froedtert Memorial Lutheran Hospital

Albert Einstein College of Medicine

The William J von Liebig Chair in Vascular Surgery

Montefiore Medical Center

New York, New York

S Martin Lindenauer Professor of Surgery

Section of Vascular Surgery

University of Michigan Medical Center

Staff Surgeon

University of Michigan Hospital and

Ann Arbor Veterans Administration Medical Center

Ann Arbor, Michigan

RODNEY A WHITE, MD

Associate Chair Department of Surgery Harbor—UCLA Research and Education Institute Chief, Vascular Surgery

Division of Vascular Surgery Harbor—UCLA Medical Center Torrance, California

Northwestern Memorial Hospital Chicago, Illinois

WILLIAM R YORKOVICH, RPA

Physician Assistant Division of Vascular Surgery Maimonides Medical Center Brooklyn, New York

CHRISTOPHER K ZARINS, MD

Chidester Professor of Surgery Stanford University School of Medicine Chief, Division of Vascular Surgery Stanford University Medical Center Stanford, California

C H A P T E R 1

A tribute to Henry Haimovici September 7,1907,

to July 10,2001

Frank J.Veith and Enrico Ascher

On July 10,2001, vascular surgery lost one of its founding

fathers, Henry Haimovici, whose interesting life was

dra-matically altered by the upheavals associated with World

War II, and who brought scholarly excellence to our

specialty

Henry Haimovici was born on the banks of the

Danube in Romania on September 7, 1907 After early

schooling in Tulcea, Romania, not far from the Black Sea,

young Henry, at the age of 20, went to Marseille, France,

for his medical education and residency training—first in

all specialties and then in general surgery He was a

distin-guished student and scholar from the beginning He

devel-oped an early interest in vascular surgery, and the title

for his thesis for his medical degree, only awarded upon

completion of his training, was "Arterial Emboli to the

Limbs." His thesis was of such high quality that Henry's

chief at the time, Professor Jean Fiolle, suggested that it be

published as a monograph It was, with a preface by

an-other pioneer in vascular surgery, Rene Leriche, who had

become one of Henry's earliest admirers and supporters

This book was of sufficient quality that it attracted the

attention of another vascular surgery pioneer, Geza de

Takats, who recommended that it be translated into

English so that "this splendid piece of work be available

to every one."

While still in training, Haimovici developed an

inter-est in venous gangrene He published one of the first case

reports on this condition and subsequently a classic

monograph on what he termed "ischemic venous

throm-bosis", a condition also known under the more popular

name, phlegmasia cerula dolens

Immediately after his residency training, DrHaimovici was selected by the dean of his medical school

to direct a new institute of neurology and neurosurgerywhich was planned as a joint project by the RockefellerFoundation To qualify for this new chief's position, DrHaimovici was sent to the United States to study neuro-physiology under Dr Walter B Cannon of Harvard Uni-versity, regarded as the most prestigious physiologist inAmerica During his year's fellowship with Dr Cannon,Henry published key papers on the effects of motor andsympathetic denervation and regeneration He alwaysconsidered Dr Cannon to be his most exceptional mentorand his time with him to be his most productive While inthe US, Dr Haimovici also met with all the neurosurgicalleaders in North America and had planned further train-ing in neurosurgery before returning to his prestigiousappointment in Marseille

However, World War II had broken out, and all of DrHaimovici's plans were disrupted He was drafted into theFrench Army, but after France surrendered he decided toaccept Dr Cannon's invitation and return to the US How-ever, his escape from occupied France involved many ad-ventures and lasted two years, by which time Dr Cannonhad retired So Dr Haimovici returned in 1942 to Bostonand the Beth Israel Hospital, where he worked with out-standing scientists such as Rene Dubos and Jacob Fine oninfections, toxic shock, and the effect of gelatin in pre-venting thrombosis of injured veins

After two highly productive years in Boston, DrHaimovici moved to New York, where he married ayoung PhD biochemist, Nelicia Maier He and his new

wife combined their interests in studying the metabolism

of atherosclerotic arteries, a field to which he would

continue to contribute for the rest of his career

In New York City, Dr Haimovici held an appointment

in vascular surgery at Mount Sinai Hospital before being

FIGURE 1.1 Henry Haimovici.

appointed chief of vascular surgery at MontefioreMedical Center in 1945 While at these two institutions,

he continued to write important articles relating the iology of the autonomic nervous system, its mediatorsand its blocking agents, to vascular conditions such asBuerger's disease and atherosclerosis His work was pub-lished in the leading medical and physiology journals ofthe time

phys-Dr Haimovici's scholarly activity extended well yond his high-quality original investigations In addition

be-to writing over 200 journal articles and book chapters, DrHaimovici authored or edited more than 10 books Hismonograph on metabolic complications of acute arterialocclusion and related conditions, published in 1988, is

now considered a classic In addition, Haimovici's lar Surgery: Principles and Techniques, first published in

Vascu-1976, is regarded as one of the finest texts in the vascularsurgery field and was also published in a Spanish edition.The first four editions of this important text were edited

by Dr Haimovici himself

Despite all these accomplishments, HenryHaimovici's crowning achievement was his role in found-ing the International Society of Cardiovascular Surgery(ISCVS) In March 1950, Dr Haimovici, who was editor

of the journal Angiology, took the initiative of organizing

the International Society of Angiology He discussed hisplans with Rene Leriche, who became the organization'sfirst president A number of the most prominent vascularsurgeons from around the world signed on as chartermembers Dr Haimovici became the organization's firstsecretary-general and drafted its original bylaws, whichcreated regional chapters for this worldwide vascular so-ciety In 1952, the first meeting of the North Americanchapter of the ISCVS (now the American Association for

FIGURE 1.2 Haimovici at the

Harvard Medical School ment of Physiology, 1939 (secondrow, fifth from left)

Depart-FIGURE 1.3 Haimovici (center) in the French Army,

1940

Vascular Surgery) was held in Chicago Emile Holmanwas elected the first president and Henry Haimovici thefirst secretary-treasurer of the chapter Meanwhile, heheld the post of secretary-general in the international or-ganization from 1950 to 1963

In this position, Dr Haimovici was a major force inorganizing the Society's first four biannual internationalcongresses, in changing the name of the Society in 1957 tothe International Society of Cardiovascular Surgery, and

in establishing its journal, the Journal of Cardiovascular Surgery He served as the founding co-editor of this publi-

cation from 1960 to 1973 and was a consulting editoruntil his death

Henry Haimovici was honored with the presidency ofthe North American chapter of the ISCVS in 1959 and

1960 He served as a visiting professor around the worldand was awarded nine honorary degrees In 1986 he waselected a corresponding member of the French NationalAcademy of Medicine, a truly unique honor for anAmerican surgeon

In his 93 years, Henry Haimovici made his scholarlymark on surgery around the globe He helped to establishvascular surgery as a true specialty, and he contributedgreatly to its scientific underpinnings He was a leadingvascular surgeon in at least two countries and was widelyknown and well respected everywhere He was a truesurgeon-scholar with an encyclopedic knowledge of thevascular literature He was a talented editor and writer,and he had organizational skills possessed by few vascularsurgeons Henry Haimovici was a colleague and a friendwho will be sorely missed, even though his mark willlong remain on vascular surgery

FICURE1.4 Haimovici (second fromright) at the French National Acad-emy of Medicine, 1986

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P A R T I

Imaging Techniques

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C H A P T E R 2

D Eugene Strandness, Jr

The past decade has seen a dramatic increase in the ability

to assess vascular disease wherever it occurs This has

been in large part due to the development of ultrasonic

du-plex scanning (1,2) This modality, which combines

imag-ing with pulsed Doppler ultrasound, permits access to all

major vascular beds, providing information that is

rele-vant to how patients are managed For some conditions,

such as deep venous thrombosis, this method has

essen-tially replaced venography as a diagnostic tool This

method is also beginning to replace arteriography for

many areas such as the carotid and peripheral circulation

(see Chapter 3) This represents a major advance that,

with time, will expand into other areas as well This

chap-ter addresses the major areas in which ultrasonic duplex

scanning can be applied not only for diagnosis, but also

for follow-up The modern duplex scanner combines two

basic modalities that can be used in concert to provide the

necessary diagnostic information (3) The essential

ele-ments of the device are as follows

Imaging

Ultrasound is reflected from tissue interfaces, making it

possible to localize and characterize structures of differing

acoustic impedance The transducer consists of

piezoelec-tric crystals that convert an elecpiezoelec-trical voltage into an

ultrasonic vibration The sound that is reflected back from

tissue is again translated into an electrical voltage that is

detected by the receiver in the instrument Those from

the more superficial structures return sooner, those

from deeper tissues return later The exact time of return is

determined not only by the distance from the energysource but also by the speed of sound in tissue, whichtends to vary somewhat depending on the tissue beinginterrogated In medical ultrasound, 154,000cm/s isused as the average speed of sound in soft tissue Thebrightness of the return echo is determined by the strength

or amplitude of the sound reflected from the tissues beinginterrogated

The most common problem that occurs with imaging

is refractive distortion (4) The pulsed imaging process sumes that the ultrasound sent into tissue returns alongthe same line in which the transducer is pointed However,because of differences in sound speed in tissue, the soundmay bend and cause structures to appear in the wrong lo-cation, particularly when viewed in the lateral region ofthe image If the ultrasound beam is perpendicular to theobject, this type of distortion does not occur It is impor-tant to understand this when one examines any imagesgenerated by ultrasound The best resolution will always

as-be seen in those tissues that are perpendicular to the soundbeam For example, as noted in Figure 2.1, the clearest im-ages are seen in the mid-portion rather than the lateralareas of the field scan

The scan format must be understood to appreciate theimages that are generated (4) Two of the various possibleapproaches are shown in Figure 2.2 With the raster scanformat, all transmission lines of the beam are parallel,whereas with the sector scan format, all lines emanatefrom a point source The scan lines in the raster format aregenerally generated by a linear array transducer The po-tential advantages of the raster format are shown in Figure2.3 If the blood vessel being imaged is parallel to the skin

7

ultrasonic Duplex

Scanning

Part I Imaging Techniques

FIGURE 2.1 in this ultrasound image of a common

carotid artery, the best resolution is in the

mid-portion of the scan At this point, the tissues of the

arterial wall are perpendicular to the sound beam

FIGURE 2.2 With the raster scan format (top), all scan

lines are parallel and all of the image planes are also

parallel The scan lines originate from a different point

along the tranducer's crystal With the sector scan

format (bottom), the scan lines originate from a small

region of the transducer (Reproduced by permission

from Beach KW, Appendix In: Strandness DE, Jr Duplex

scan-ning in vascular disorders, 2nd edn New York: Raven Press,

1993:284.)

and at right angles to the scan lines, optimal images are

ob-tained However, if a vessel begins to deviate from this

parallel path, image quality may begin to degenerate and

some structures such as the double line representing the

thickness of the intima-media are no longer seen With the

FIGURE 2.3 With the raster scan format and the artery

parallel to the skin surface, the double line on theposterior wall of the artery, which represents thecombined thickness of the intima and media, can bevisualized throughout the length of the scan

(Reproduced by permission from Beach KW, Appendix InStrandness DE, Jr Duplex scanning in vascular disorders, 2ndedn New York: Raven Press, 1993:285.)

sector format, the optimal image area is more limited, asshown in Figure 2.4 Both of these formats have certainadvantages that vary depending upon the intendedapplications

There are also innumerable variations on how thetransducers function These range from electronic beamsteering to curved and concave linear array transducers,each of which has specific advantages for some applica-tions No single transducer design will satisfy all applica-tions Readers interested in more details are urged toconsult the more complete coverage of this subject byBeach (4)

Although the scan format used is important, it is alsonecessary to understand the role of the transmitting fre-quency, its application, and its effect on the performance

of the system (4) Attenuation of the signal is directly lated to the transmitting frequency The goal is to obtainsignals (images) with the maximum possible resolution.For superficial structures a high transmitting frequency of

re-5 MHz is satisfactory, but for deeper structures, such asthe renal arteries, a much lower transmitting frequency of2.0-3.5 MHz may be needed There is less attenuation ofthe ultrasound signal with the lower frequencies, makingthem better for visualizing deeper structures

Doppler

The Doppler ultrasound used in nearly all modern tems is pulsed, making it possible to selectively sampleflow from any point along the sound beam (5) As with theimaging, knowing the speed of sound in tissue makes itpossible to range gate return signals to assess flow velocity

sys-at any depth thsys-at is reachable by the ultrasound frequencyused The size of the sound packet (the sample volume)

Image Not Available

Image Not Available

FIGURE 2.4 With the sector scan format, the double

line that represents the intima and media is seen only

in a limited portion of the scan plane as shown

(Re-produced by permission from Beach KW, Appendix In:

Strandness DE, Jr Duplex scanning in vascular disorders, 2nd

edn New York: Raven Press, 1993:285.)

for all pulsed systems can be varied considerably

depend-ing upon the intended application The sample volume

has both length and width Its length is determined by

the duration of the sound burst and its width is

deter-mined by the focusing characteristics of the transducer

(Fig 2.5)

The size of the sample volume can be adjusted by

the user, so it is important to review how it might be used

and the problems that one might encounter with

impro-per use (6)

1 When examining arteries such as the carotid or

femoral, one would like to use as small a sample

vol-ume size as possible If one widens the sample volvol-ume

to encompass the entire artery, the received signal will

be identical to that obtained with continuous wave

Doppler ultrasound Figure 2.6 illustrates the basis for

this observation Near the normal arterial wall, the

ve-locity gradients are very steep, resulting in the

record-ing of a broad range of frequencies This broadens the

velocity spectrum (7,8) As noted, spectral

broaden-ing is not seen with a small sample volume placed in

the center stream of the common carotid artery This

can be confusing if one attempts to use spectral

broad-ening as a parameter for diagnosing carotid artery

stenosis This will be covered in detail later

FIGURE 2.5 The area in tissue insonated by a

continu-ous wave Doppler is contrasted with that insonated

by a pulsed system As noted, the width of the samplevolume can be varied by the degree of focus provid-

ed (Reproduced by permission from Strandness DE,

Jr Duplex scanning in vascular disorders, 2nd edn New York:Raven Press, 1993:20.)

2 A large sample volume is of benefit when one is ining arteries that experience a great deal of move-ment with respiration The best examples of these arethe renal, celiac, hepatic, splenic, and mesenteric ar-teries With the large sample volume, flow can bemonitored during an entire respiratory cycle, avoid-ing the intermittent loss of the signal due to move-ment of the sample volume in and out of the artery.One important difference between pulsed and contin-uous wave systems is the problem of aliasing (4) Nyquistnoted that, in order to faithfully record frequencies, it wasnecessary to have at least one sample taken for every peakand one for every valley of a waveform This is the reasonthat the sample rate [the pulse repetition frequency (PRF)]must be at least twice the transmitting frequency of thepulsed Doppler Thus, if one needed to record Doppler-shifted frequencies of 5 kHz, it would be necessary to use apulse repetition frequency of 10 kHz If the Doppler shiftwere to exceed this limit, the frequencies that exceeded the

exam-5 kHz level would appear beneath the zero frequency line(Fig 2.7)

There are ways to circumvent this problem One is

to simply increase the PRF of the instrument Another

is to reduce the transmitting frequency of the transducer.Finally, it is possible to combat aliasing by baselineshifting, which moves a portion of the reverse flow dis-play to the forward flow location This method is verycommonly used in the currently available systems.The methods used for signal processing of theDoppler data are one of the most important advances inthe field For the velocity data that are recorded to be use-ful, they must be analyzed in a format that displays all ofthe pertinent information in the Doppler spectrum The

10 Part I Imaging Techniques

FIGURE 2.6 These velocity recordings are an ensemble

average of 16 heart beats taken as the sample volume

is moved from close to the anterior wall of the

com-mon carotid artery to the vessel lumen and to the

posterior wall region Near the walls, the spectrum is

"filled in" (spectral broadening) owing to the very

steep velocity gradients near the wall (Reproduced by

permission from Strandness DE, Jr Duplex scanning in

vascular disorders, 2nd edn New York: Raven Press,

1993:SG.)

most versatile method in use is fast Fourier transform

(FFT) spectrum analysis (4,8) This method has become

the standard for displaying all Doppler data with both

continuous wave and pulsed systems The display has

fre-quency (velocity) on the ordinate and time on the abscissa

It also provides information relative to the intensity of the

backscattered ultrasound, but for most clinical purposes

this information is not used

From a practical standpoint, the most useful clinical

data relate to velocity since they are the most sensitive to

change in vessel dimensions As will be shown, velocity

criteria are the most commonly used to detect and grade

the degree of narrowing of arteries (3,9) The other

com-monly used parameter is spectral broadening If blood

flow is laminar and the recording is taken from the center

stream of the artery, the area beneath the systolic peak will

be clear (6-8) On the other hand, if there is turbulence,

the red blood cells are no longer moving at a uniform

FIGURE 2.7 Aliasing of a spectral waveform when

pulsed Doppler ultrasound is used and the recordedfrequencies exceed the pulse repetition frequency(PRF) of the pulsed system, on the left, there isfoldoyer of the peak velocity, which is corrected bydoubling the pulse repetition frequency shown onthe right (Reproduced by permission from Strandness DE,

Jr Duplex scanning in vascular disorders, 2nd edn New York:Raven Press, 1993:20.)

velocity and the systolic window will be filled (10) ever, spectral broadening is being used less because of itsqualitative nature To interpret it properly, it is necessary

How-to know precisely from which regions in the artery theflow is being detected, as well as the size of the samplevolume being used (see Fig 2.6)

If one uses continuous wave Doppler ultrasound, allvelocity data in the path of the beam will be recorded (6).Since the velocity of flow near the wall of an artery isslower, one will record all velocities up to and includingthe peak, which is usually in the center stream of theartery On the other hand, with pulsed Doppler ultra-sound, if a large sample volume were employed thatencompassed the entire cross-sectional area of the artery,its output would be identical to that of a continuouswave Doppler ultrasound and would provide similartypes of FFT displays It is also clear that, depending uponthe intended application, the technologist will vary thesample volume size used For example, in the case of thecarotid artery, it is preferable to use as small a sample vol-ume as possible (10) In contrast, studies of the renalartery often require a larger sample volume for the veloci-

ty data to be continuously recorded throughout each piratory cycle (11) If a small sample volume were used,the artery would move in and out of the sample volumewith respiration

res-In theory, it is possible to record absolute velocitieswith Doppler methods; therefore, it is important to reviewbriefly some of the concerns and problems that can occurwith this method The major factors that determine therecorded velocity are the transmitting frequency and theangle of the sound beam with the velocity vectors that areencountered (12) The choice of transmitting frequency

will depend upon intended application For superficial

vessels, a higher transmitting frequency (5-10 MHz) is

used; for deeper vessels, lower frequencies (2.0-3.5 MHz)

are used

The angle of incidence is the most difficult variable to

control for transcutaneous use The ideal would be to

have the sound beam directed down the center stream of

the artery parallel to the velocity vectors When this is

pos-sible, the incident angle of the sound beam is zero, giving a

cosine value of 1 Because this is rarely possible in clinical

use, one must estimate the angle of incidence of the beam,

which can then be used to calculate the angle-adjusted

ve-locity This is done automatically by the duplex scanners

currently in use However, even with this approach there

can be problems that must be appreciated One of the

most difficult is the problem of nonparallel velocity

vec-tors, which are continually changing the angle of the

inci-dent sound beam (12) Nonparallel velocity vectors are

common in the arterial system and are always found in the

vicinity of branch points and bifurcations (7) Also, once

the velocity vectors begin to deviate from what one might

expect, a finite distance from the source of the velocity

dis-turbance must be traversed before the vectors again

as-sume a laminar flow pattern

A few examples of this problem and the need for its

understanding are shown in Tables 2.1 and 2.2 In Table

2.1, velocities were recorded from the common carotid

artery using different angles of incidence of the sound

beam In theory, this should make no difference in the

recorded velocity, particularly if the velocity vectors were

parallel to the wall However, as noted, there are

varia-tions in the calculated velocities that must be related to

di-rectional changes in the flow vectors In Table 2.2, the

recordings were made from the superficial femoral artery,

TABLE 2.1 Doppler frequency and angle-adjusted

velocity from common carotid artery

97105117145

3.5612.9062.2921.524

Angle-adjustedVelocity (cm/s)73717270

and an entirely different situation was found Here,changing the incident angle of the sound beam had verylittle effect on the angle-adjusted velocity In this situation,flow is much more stable (laminar), thus permitting amore realistic estimate to be made This clearly illustratesthe differences that can be found depending upon the sam-pling site within the arterial system

These types of data also emphasize the importance ofusing a constant Doppler angle for all studies in patientswhenever that is possible We prefer to use 60°, which isquite easily obtained in most situations (12) However, ifthis angle of incidence is not obtainable, the technologistmust record the angle used In addition, if follow-upstudies are to be performed, the same angle must be used.This will provide consistency among the data obtained.Although most manufacturers refer to the use of angle-corrected velocities, we prefer the term angle-adjustedvelocity as representing a more realistic situation for dailyclinical practice (4) It is also clear that, because we rarelyhave the ideal situation for making recordings, thevelocity data we obtain is, in general, an estimate

FFT depictions of velocity data have become standardfor nearly all instruments, but now "color Doppler" and

"power Doppler" have added an entirely new dimension

to ultrasound studies (13-15) The color can be obtainedwith a variety of transducer systems The Doppler image isformed by analyzing the phase changes between echoesfrom each scan line In order to generate one scan line, a se-ries of echoes is required For each depth, the phase changefrom echo to echo is measured to determine the frequencyshift A color is assigned to the corresponding depth ac-cording to its direction and velocity In practice, shades ofred and blue are used, although this is arbitrary

Color has great appeal because it provides a nearlyinstantaneous presentation of the velocities, which hasthe following advantages (14):

1 The local vascular anatomy is immediately displayed

2 The relation of flow to the wall is apparent

3 Areas of narrowing and turbulence may be detected

4 The direction of flow is detected

5 Regional changes in velocity can be seen

Even given all of the advantages of color, there areproblems that need to be faced because they can adverselyaffect how the data are generated and interpreted Some ofthe problems are as follows:

1 Aliasing can occur with color

2 Changes in the direction of the velocity vectors willresult in a change in the hue of the color, which may bemisinterpreted as an absolute velocity change

3 The frequency shift information referable to the colorbar and velocity should not be construed as represent-ing a true value The velocity data obtained with colorare mean values (4)

4 The temptation to make direct measurements of thedegree of stenosis as an index of the degree of narrow-

12 Part I Imaging Techniques

ing must be resisted Simply changing the gain can

drastically alter what one might consider to be the

lumen of an artery

Power Doppler does not display the frequency change

at the site of interrogation It reflects the amplitude of

the backscattered frequencies—not the Doppler shift

This has certain advantages, particularly when one is

interested in the arterial anatomy or the geometry of a

stenosis It is a valuable adjunct to the other aspects of

duplex scanning

Medical Applications of Ultrasonic

Duplex Scanning

Ultrasonic duplex scanning has reached such a level of

maturity that it is now possible to draw some conclusions

about its use in cardiovascular medicine (3) There are few

technologies currently available as cost-effective or

gener-ally as useful as duplex scanning in clinical medicine As

will become evident, no other diagnostic instruments have

the versatility found with duplex scanning Nearly every

area of clinical interest and need can be studied with this

method

The Carotid Artery

The first area in the circulation to be studied by duplex

scanning was the carotid artery (16) This was done for

several reasons: first, its proximity to the skin makes it

easily accessible to ultrasound; and, second, disease in this

location is common and is frequently studied by contrast

arteriography This made it possible to validate the

accuracy of duplex scanning in detecting the presence of

disease and estimating its severity It is now clear that

arteriography is not a good gold standard for this purpose

Atherosclerosis commonly affects the extracranial

circulation but has the highest incidence at the level of the

bulb The carotid bulb is a unique area in the circulation

owing to its geometry It is the only region of the arterial

system where a regional dilation is found The geometry

of the bulb creates peculiar flow patterns that can be a

source of great confusion if their presence is not

recog-nized (8) It has been theorized that this geometry and the

resulting flow patterns explain the localization of the

atheroma to this region As all vascular surgeons

recog-nize, the disease rarely extends beyond the distal limit

of the bulb itself, which is one reason that carotid

endarterectomy is feasible

The flow changes in the normal bulb that are unique

are referred to as boundary layer separation (8) As the

flow enters the bulb, that flow near the flow divider will be

antegrade at all times in the pulse cycle, while that in the

posterolateral region will reverse The area of reverse flow

is the region of boundary layer separation (8) The size of

this region varies during the pulse cycle As flow leaves

the bulb, a helical flow pattern will be generated that ispropagated for varying distances into the internal carotidartery

The presence of boundary layer separation can bedemonstrated both with FFT displays and with color (Fig.2.8) The dramatic nature of the flow changes during asingle pulse cycle can be seen in the FFT display The im-portance of understanding boundary layer separation isthat it does not occur when an atheroma fills the postero-lateral region of the bulb; that is, it is only seen with a nor-mal bulb In clinical medicine we must deal with therelation between the extent of disease and the clinicaloutcome, so it is important to develop criteria that can beused to dictate how the patient should be treated Over thepast several years, we have developed categories of diseaseinvolvement detectable by duplex scanning that are ofgreat practical value These can be summarized as follows(10):

FIGURE 2.8 in the normal bulb, an area of recirculation

is found in the posteriolateral aspect of the bulb, inthis area, flow will be both antegrade and retrograde.With the sample volume near the flow divider, all flow

is antegrade However, with the pulsed Doppler ple volume moved to the lateral aspect of the sinus,both forward and reverse flow components are seen.This is referred to as boundary layer separation.(Reproduced by permission from Strandness DE, Jr Duplexscanning in vascular disorders, 2nd edn New York: Raven

sam-Press, 1993:113-157.)

risk is clearly associated with how much narrowing is

psent The highest risk is in the 80% to 99% diameter

re-duction category After the early reports that only the 70%

diameter reducing lesions were significant, we began to use

another velocity-derived parameter to classify this degree

of diameter reduction The algorithm for its detection is

easily adapted to the criteria already in common use (19)

The diagnostic criteria for determining the degree of

diameter reduction are related to two ultrasound features

(Fig 2.9): peak systolic velocity and end-diastolic

velocity We have stopped using spectral broadening

except in special circumstances They are used in the

following fashion:

1 Normal bulb The major diagnostic finding is

bound-ary layer separation

2 Diameter reduction <50% Disease is seen in the bulb

on imaging but it does not increase the peak systolic

flow velocity across the bifurcation

Diameter reduction >50% but <79% There is an

in-crease in the peak systolic velocity at the stenosis thatexceeds 125cm/s

Diameter reduction 80% to 99% The end-diastolic

frequency now is greater than 145 cm/s This is the sion that is most likely to proceed to total occlusion

le-Of course, the peak systolic velocity will be muchhigher To classify a lesion in the >70% diameter re-ducing range, it is necessary to divide the peak systolicvelocity at the site of the stenosis by the peak recordedfrom the common carotid artery If this ratio exceeds4.0, there is a 90% chance that the lesion exceeds thiscutoff value (19)

Total occlusion No flow will be detectable in the

in-ternal carotid artery However, there are other cluesthat are useful in suspecting this finding These in-clude the following: 1) end-diastolic flow in the com-mon carotid artery will often go to zero; in 34 cases oftotal occlusion, end-diastolic flow went to zero in 32;

FIGURE 2.9 The spectral criteria

used for detecting varying degrees

of stenosis of the carotid artery areshown The major features, with in-creasing degrees of narrowing, in-clude the peak systolic velocity, theend-diastolic velocity, and spectralbroadening (see text)

14 Parti Imaging Techniques

2) flow in the contralateral carotid artery will be

dou-bled as it now supplies both hemispheres, which

re-sults in a marked increase in the end-diastolic

velocity; 3) as the sample volume is positioned close

to the occlusion, a "thumping" sound may be heard

that is very distinctive of total occlusion; and 4) there

will be no flow in the internal carotid beyond the

bulb—although one might think that color flow

would be the best method of detecting a total

occlu-sion, this has not been verified to date It should be

noted that flow in the contralateral carotid will be

much higher so it may be necessary to downgrade the

degree of narrowing there by one category (3)

Because a total occlusion removes the patient from

surgical consideration, this diagnosis is of paramount

im-portance In many cases, it will be necessary to obtain an

arteriogram to render the final judgment, but even here

there can be problems if the residual flow channel in the

stenosis is very narrow and the flow very slow

The accuracy of duplex scanning as a method of

de-tecting and classifying the degree of stenosis has been well

established (10) Its sensitivity is in the range of 98% with

a specificity that is in the 95% range, which makes it

satis-factory for screening populations with either a high or low

prevalence of disease (20)

Screening Before intervention

The majority of patients with extracranial arterial disease

who develop ischemic episodes will do so secondary to

disease within the bulb Although there is no doubt that

lesions at the level of the aortic arch can lead to transient

ischemic events and strokes, this is very uncommon

However, precise criteria for grading the degree of

nar-rowing of the arteries at the level of the arch have not been

worked out with the same precision It is possible to detect

turbulent flow patterns in the proximal common carotid

artery that are a clue that problems exist at that level (21)

Clearly, for lesions in the innominate and subclavian

artery, arm pressures must be measured along with direct

insonation of the subclavian arteries This can be helpful

in detecting clinically significant disease A systolic

pres-sure gradient of more than 15mmHg between the two

arms could be significant

Another area that has been of concern is the carotid

siphon (22) It is well known that lesions can develop in

this region that might be a cause of ischemic events This

area cannot be studied by duplex scanning However, the

studies that have been performed examining the role of

the siphon have not supported the impression that lesions

here are a cause of ischemic events This region can now be

evaluated by transcranial Doppler ultrasound, but there is

not yet sufficient information to determine if this method

is of any value for this purpose

As duplex scanning is an accurate screening test for

le-sions of the bulb (23,24), could it be used as the sole

diag-nostic test before carotid endarterectomy? The concern is

that the information obtained by duplex scanning alone

might not prove sufficient to proceed safely with the ation To address this issue, it is necessary to consider theproblems that could occur to negate the use of duplexscanning alone:

oper-1 The key element is a properly performed duplex scanthat accurately assesses the location and extent of theinvolvement In the results of the NASCET and ECSTstudies, the degree of stenosis was the only factor thatdetermined the need for endarterectomy (17-20).The published results from good laboratories wouldsuggest that a well-done test is as accurate as arterio-graphy in determining the degree of narrowing Thismeans that vascular surgeons must have confidence inthe laboratory doing their testing procedure Thismeans good quality control and experience (21-23)

2 Does arteriography provide additional informationthat would preclude operation or suggest a differentapproach? There are obvious lesions, particularly atthe intracranial level, that would, or could possibly,change the approach These include aneurysms,tumors, and occlusive lesions in the distribution ofthe middle cerebral artery Mass lesions would bediscovered by the computed tomography (CT) scan,but occlusive lesions would not

3 Lesions at the level of the aortic arch may dictate a ferent approach because if undiscovered they maylead to failure of the carotid endarterectomy Thispossibility can be avoided by a careful examination ofthe flow patterns at the level of the aortic arch (24).Interestingly, lesions in the siphon do not appear tocontribute to the outcome after endarterectomy Thelesions which occur in the siphon are not generallydue to atherosclerosis but are known as intimalcushions, which are smooth and do not appear toulcerate (25)

dif-We have carried out two prospective studies to assessthe role of duplex scanning alone for the selection ofpatients for endarterectomy (26,27) Over a 29-monthperiod, the vascular surgeons involved in the study had tomake decisions relative to the management of 103 pa-tients who were being considered for carotid endarterec-tomy (111 carotid arteries) For each case, the surgeonrecorded his plan before the arteriography Nine patientswere excluded because arteriography was not carried out,

or was performed before the surgeon's evaluation Theduplex scans were diagnostic in 87 (93%) of the 94cases The carotid lesion was inadequately evaluated byduplex scan in seven patients because the disease wasnot limited to the distal common carotid artery or bulb(four cases), anatomic or pathologic features of thecarotid artery interfered with imaging or Doppler analysis(one case), or a lesion could not be distinguished with cer-tainty as an occlusion (two cases) When the duplex scanwas adequate, the arteriography contributed informationthat was of additional value in only one case (1%) Thispatient had a middle cerebral artery stenosis distal to a

high-grade stenosis Operation was withheld because of

this intracranial stenosis Later, he sustained a completed

stroke that might well have been secondary to the carotid

bifurcation stenosis We concluded that duplex scanning

could be used as the sole preoperative study as long as a

satisfactory, complete duplex scan had been performed

Our data suggest that a perfectly satisfactory outcome

could be achieved by this approach In fact, there are

clin-ical trials under way that accept duplex scanning alone as

the method used for selecting patients for endarterectomy

Postoperative Studies

In the early postoperative period (first week), testing can

be done but is generally used to determine the patency of

the internal carotid artery Because of the fresh wound and

the patient's discomfort, it is not always possible to carry

out a complete study However, within 7 to 10 days, a

more complete examination can be done if it is deemed

necessary

During the follow-up period, the major lesion that

develops is myointimal hyperplasia (28,29) This is a

smooth lesion that will develop within the first 12 months,

and is not a common cause of ischemic events Some of

these lesions can proceed to total occlusion, but this

ap-pears to be very uncommon The progression to internal

carotid artery occlusion after operation was found

in 4% of the 200 consecutive patients we have followed

prospectively (28)

The Peripheral Arterial System

The most widely used noninvasive test for peripheral

arte-rial disease is the measurement of the ankle-arm index

(AAI), followed in some instances by exercise testing

(30-34) This provides the necessary objective baseline

values for both establishing the diagnosis and following

the progress of the disease with and without

intervention-al therapy If the patient is a candidate for intervention,

the next diagnostic study performed is arteriography This

study provides the necessary road map for the surgeon in

reconstructing the arterial system Is this approach

ade-quate or can we make significant progress by adding

du-plex scanning for specific cases (34,35) ? The issue of using

duplex scanning alone prior to operation will be

consid-ered in greater detail in Chapter 3

In order to determine the place for duplex scanning in

diagnosis, it is necessary to establish its accuracy

com-pared with arteriography, which is still considered to be

the gold standard Progress in the implementation of

du-plex scanning for the peripheral arteries had to await the

necessary technological improvements that guaranteed

access to all arteries of interest For clinical purposes, it is

necessary to scan the arterial system from the level of the

abdominal aorta to the ankle arteries and, in the upper

ex-tremity, from the level of the subclavian artery to those at

the wrist

Based upon previous experience with physiological

studies and those conducted with continuous wave

Doppler ultrasound, a great deal is known about the mal arterial flow patterns and their use in documentingboth the presence and extent of disease The most impor-tant fact to understand is that the velocity patterns are dic-tated by the vascular resistance offered by the tissuesupplied and its metabolic activity at the time of study.There are some generalizations that are useful The organsand systems that are low-resistance vascular beds are thebrain, liver, spleen, and kidney These organs demand highlevels of blood flow at all times during the day In the sup-plying arteries, the end-diastolic velocity should always beabove the zero baseline (Fig 2.10) The high-resistance ar-terial beds are the upper and lower extremities under rest-ing conditions (35,36) At rest, a reverse flow component

nor-of the velocity waveform will be prominent until the tance to flow decreases, such as occurs with and immedi-ately after exercise (Fig 2.11) The upper limb velocitypatterns are more variable because some individuals willnot show a reverse flow component even at rest In thelower leg arteries, reverse flow should always be seenwhen the patient is at rest There are arteries supplying tis-sues of intermediate resistance The most common andfrequently studied by duplex scanning is the superiormesenteric artery Under fasting circumstances, a small

resis-FIGURE 2.10 With a low-resistance type of waveform,

the end-diastolic velocity is always above zero This waveform was taken from the mid-portion of the right renal artery (RRA) Ao, aorta (Reproduced by permission from Strandness DE, Jr Duplex scanning in vascular disorders, 2nd edn New York: Raven Press, 1993:200.)

16 Part I Imaging Techniques

FIGURE 2.11 The high-resistance waveform typically

has a reverse flow component as shown here from

tracings taken from the external iliac artery (EIA), the

common femoral artery (CFA), and the proximal

superficial femoral artery (SFA-p) (Reproduced by

permission from strandness DE, Jr Duplex scanning in

vascular disorders, 2nd edn New York: Raven Press, 1993:

166.)

amount of reverse flow is seen in the superior mesenteric

artery Within 20 minutes of eating, this pattern begins to

change, with a loss of the reverse flow component and an

increase in the end-diastolic velocity as the volume blood

flow to the gut increases to meet the metabolic demands of

digestion (Fig 2.12) Interestingly, this same phenomenon

is seen with the inferior mesenteric artery, but the flow

ve-locity change occurs only when the material ingested is

handled by the colon The blood flow in the inferior

mesenteric artery does not appear to change when foods

ingested are handled primarily by the stomach and small

bowel

Given these considerations, it is possible to utilize

ve-locity data as diagnostic aids in assessing the status of the

arterial system Documentation of an abnormality

pends upon demonstrating flow velocity changes that

de-viate from this normal pattern As with other arterial

beds, the extent to which the patient becomes

sympto-matic depends upon both the location and, most

impor-tantly, the degree of narrowing that is present In the

B

FIGURE 2.12 Changes that occur with vasodilation of

the mesenteric vascular bed after food ingestion areshown (top) Taken during fasting and (bottom) afterfood ingestion There is a dramatic increase in boththe peak and end-diastolic velocities noted (Repro-duced by permission from Strandness DE, Jr Duplex scan-ning in vascular disorders, 2nd edn New York: Raven Press,1993:69.)

peripheral arterial circulation, patients will becomesymptomatic only when the pressure and flow beyond thelesion begin to decrease, making it impossible to maintainadequate nutritional flow either with exercise or at rest Ingeneral, the level of narrowing that is sufficient to do this

is a 50% or greater degree of diameter reduction This isoften referred to as a critical stenosis (37) However, somestenoses that narrow the artery by less than this amountcan become hemodynamically significant under condi-tions of increased blood flow (38) In this case the increase

in flow across the narrowed segment will induce lence that accentuates the normal pressure gradient.When there is a decrease in pressure and flow during exer-cise, the patient may develop intermittent claudication.Given the above, it is clear that if duplex scanning is

turbu-to partially or completely replace arteriography, it willhave to be able to detect and grade lesions of all levels ofseverity (39) There are also other considerations thatare relevant to this question

1 The studies have to be done at the sites of disease

in-volvement This means, of course, that long lengths of

the arterial system will have to be scanned

2 The changes in flow velocity across the stenotic

lesions should be a reflection of the degree of

narrowing

3 The information must have clinical relevance for the

physician in his or her management of the patients

and their problems

4 The testing will have to be cost-effective and not just

another test providing information that is already

available from existing and, in some cases, less

expen-sive tests

5 The testing should provide data that can be used for

follow-up comparisons It has become increasingly

clear that accurate, objective follow-up is very useful

in making sure that the benefits of therapy can

continue Several examples of this will be covered

later in this chapter

6 Technologists should be capable of performing the

tests

For study purposes, the systems used must be

state-of-the-art, with color Doppler ultrasound and a variety of

transducers with different transmitting frequencies

Be-cause the arteries in the abdomen are deeper than those in

the leg, lower transmitting frequencies in the range of 2.0

to 3.5 MHz for imaging may be required For most

appli-cations, a 5-MHz system is adequate for Doppler studies

The scanning commences in the upper abdominal

aorta, proceeding distally to the arteries at the level of the

ankle The technologist is testing for areas where the peak

systolic velocity increases from one segment to another

The criteria that have emerged can be considered in two

categories, each of which is very dependent upon the

other The role of color/power alone is reviewed below,

but it cannot be divorced from the simultaneous use of the

FFT real-time spectral analysis

Color/power Doppler ultrasound provides certain

advantages related primarily to rapid identification of the

vessels of interest as well as the sites of the lesion(s) and a

rough estimate of their severity (13-15) Color Doppler

alone must not be used to quantitate the absolute velocity

values It provides data only on the means and not the

ab-solute values for the peaks (4) Power Doppler is based on

the amplitude of the backscattered ultrasound and not the

velocities With experience, color has been useful in the

following ways:

1 The normal flow pattern of triphasic flow can be

rec-ognized by the transient appearance of blue (reverse

flow), which becomes apparent during late systole

and early diastole (14,36)

2 With a stenosis there are two changes that suggest

that it may be a lesion with more than 50% diameter

reduction (15) The first is the appearance of

turbu-lence, which is seen as an admixture of colors just

distal to the stenosis The other indirect sign is the pearance of a bruit This is recognized as the appear-ance of spontaneous bursts of color outside thearterial wall This represents arterial wall vibration It

ap-is only seen at and dap-istal to a stenosap-is, which ap-is consap-is-tent with the clinical observation that bruits arealways transmitted downstream of the area ofnarrowing

consis-3 An occlusion is recognized by two features (15) One

is the lack of color flow at sites where it should befound The other is the appearance of collateral ves-sels that take their origin at right angles to the artery.Since this dramatic change in direction of flow, which

is now either toward or away from the transducer, thecolor change at the site of origin of the collaterals will

be dramatic In most cases, the color will be a verylight shade of red, or even white, reflecting this dra-matic change in the direction of flow

4 Power Doppler is particularly useful in identifying theanatomy of the segments being examined For exam-ple, the tortuosity seen in the internal carotid arterymay be difficult to sort out, but power Doppler makesthis much easier

These color changes are important, but, as mentionedearlier, the best method of determining the actual velocity

at suspected sites of narrowing is to make use of the singlesample volume of the pulsed Doppler and the FFT to give

an accurate measurement of the true velocities at areas ofnarrowing Although the color provides the road map,

we still must rely on the velocity changes as follows(Fig 2.13):

• Normally, there should not be a detectable change inpeak systolic velocity in short segments of arteries.However, it is well recognized that there is a gradualdecrease in peak systolic velocity as one moves downthe limb from the level of the abdominal aorta to thetibial arteries at the ankle (36)

• With roughening of the arterial wall but without ameasurable degree of narrowing, the only detectablechange will be some spectral broadening (36) For thiscategory we have labeled the disease as being in the1% to 19% category of diameter reduction

• As the lesions progress there will be a progressiveincrease in the peak systolic velocity (32,33) Forstenoses in the 20% to 49% category of diameter re-duction, the peak systolic velocity will increase be-tween 30% and 100% over that in the precedingsegment Most importantly, there will be spectralbroadening but the reverse flow component is gener-ally preserved These are not a clinical problems whenthe patient is at rest However, in some cases with theincrease in flow that accompanies exercise, turbu-lence can develop which can lead to a pressure drop

• For the pressure and flow-reducing lesions (> 50% ameter reduction), the peak systolic velocity within

di-18 Part I Imaging Techniques

FIGURE 2.13 The spectral criteria used to separate the

varying degrees of involvement of the peripheral

ar-teries are shown (A) With the normal artery the

triphasic waveform without spectral broadening is

seen (B) With 1-19% wall roughening, reverse flow is

retained but some spectral broadening can be noted

(C) in the lesions with 20-49% diameter reduction, the

peak systolic velocity will increase by 30% to 100%

from that of the preceding segment with spectral

broadening noted Reverse flow may be preserved

(D) in the lesions with 50% to 99% diameter reduction,

the peak systolic velocity increases by more than

100% from that of the preceding segment

(Repro-duced by permission from Strandness DE, Jr Duplex

scan-ning in vascular disorders 2nd edn New York: Raven Press,

1993:169.)

the stenotic segment will increase by more than 100 %over that in the preceding segment, with a loss of thereverse flow component and the development ofmarked spectral broadening (35,36)

« Total occlusion is recognized by the absence offlow

These criteria have been prospectively tested againstarteriography, with the results shown in Table 2.3 Whenone examines the accuracy of duplex scanning and com-pares its results against those of arteriography, the ultra-sonic method does quite well The comparison betweenduplex scanning and the reading of a single arteriogra-pher does not tell the entire story because there is anotherelement of variability in the reading of the arteriograms

To evaluate the interobserver variability, we compared theresults when the films were read by two radiologists (seeTable 2.3) (36) Because only the stenoses with diameterreductions of less than or more than 50 % are clinically rel-evant, this subset of stenoses was chosen for comparison

In this study, both radiologists used calipers to measure ameter reduction The senior radiologist was arbitrarilyused as the gold standard The results for this study aresummarized in Table 2.4 for the positive and negative pre-dictive values for the segments studied

di-These types of data reinforce the belief that the goldstandard also has limitations, as does duplex scanning.However, this does not negate the potential role for theultrasonic method Either method must be used in thecontext of the clinical presentation For example, if thepatient has intermittent claudication and a superficialfemoral occlusion but there is also a suggestion of an iliacartery stenosis, a negative duplex scan of the feeding iliacartery would appear to be sufficient to direct attention tothe femoral artery lesion alone

Screening Before InterventionThe patients for whom we have reserved duplex scanningare those considered candidates for intervention, be it en-dovascular or surgical (40) To prospectively test the role

of duplex scanning, we conducted a study that included

122 patients who had undergone both duplex scanningand arteriography There were 110 arteriograms that

TABLE 2.3 Duplex scanning versus arteriographyfor a stenosis of less than or greater than 50% diameter

6784677582

100909893819792

100758090538680

100969688889393

TABLE 2.4 Comparison of two radiologists in

classifying arterial lesions into categories of less

than or more than 50% diameter reduction

Arterial Segment

Iliac

Common femoral

Superficial femoral (proximal)

Superficial femoral (middle)

Superficial femoral (distal)

Popliteal

All segments

Positive Predictive Value (%)

941001001007810088

Negative Predictive Value (%)

96918893949593

The senior radiologist was arbitrarily used as the "gold standard."

were preceded by duplex scans Of this group, 45 were

scheduled for angioplasty on the basis of the results of the

duplex scan Angioplasty was performed in 47 of these

cases In one patient, the lesion was felt to be too

danger-ous to dilate In a second patient, a significant pressure

gradient was not found across the area of stenosis In a

third patient, a stenosis in the superficial femoral artery

distal to a total occlusion was missed

Is this approach worthy of the extra effort and time?

At present, there are several reasons why these appear to

be acceptable First, if duplex scanning is as accurate as

two radiologists reading the same films, why not apply it

as a screening test? Second, it is likely that the number of

arterial punctures was reduced because the radiologists

knew before the procedure where the lesions were to be

found Third, this method is likely to reduce the total

number of arteriograms obtained It appears that many

radiologists and surgeons use arteriography as the initial

diagnostic procedure, then decide what approach should

be used at a later time Finally, this is a very satisfactory

ap-proach in that patients can be made aware of the proposed

form of therapy and the likelihood of success

Vein Mapping

The saphenous vein is the most satisfactory bypass graft

for peripheral arterial occlusive disease, so it is important

to determine its adequacy before surgery The advantages

of preoperative ultrasonic assessment are as follows (41)

1 Anatomic variants are not uncommon, being found

in 30% to 70% of patients

2 Double systems are not uncommon It is worthwhile

to scan patients who have had a vein stripping

be-cause a duplicate system that may be usable can

occa-sionally be found

3 Areas of scarring or occlusion within the vein may

be found, which will require the modification of the

procedure

4 The size of the vein may be estimated, providing some

confidence as to its suitability as a conduit In general,

a vein with an internal diameter of 2 mm is suitablefor bypass purposes

5 Alternative sources for veins can be determined

in those patients in whom the greater saphenous iseither absent or inadequate

In the prospective studies that have been done, thesensitivity of duplex scanning was found to be in the 93%

to 96% range The positive predictive value was also inthis range The specificity is not as high, being in the range

of 60% to 70% In some cases, it is necessary to explorethe suspicious venous segments to be certain of theirstatus In some patients whose lower limbs do not havesuitable veins, it may be necessary to screen the armsfor a possible conduit

In order to do the study, it is necessary to use a resolution B-mode system The linear array transducers(7-10 MHz) have an advantage in that long segments ofvein can be seen in the field, which makes the scanningtime faster To facilitate the examination, it is best to dothe study with the leg in a dependent position, which caneither be the reverse Trendelenburg or the standing posi-tion This provides maximal venous dilation, which is im-portant both for visualizing the vein and for determiningits diameter The scanning procedure takes 20 to 30 min-utes, and the technologist can then mark the course of thevein, along with large branches that might be of concern

high-Follow-up

Once the surgical or endovascular procedures is pleted and the patient has left the hospital, the long-termoutcome is dependent upon two major factors One is theproblem of myointimal hyperplasia (42) This interestinglesion may develop when there has been some inj ury to thevessel wall The lesion, in its most simple terms, is an over-growth of smooth muscle that may significantly narrowthe artery or graft at the site of development If the nar-rowing becomes sufficiently severe, the procedure mayfail The exact incidence of myointimal hyperplasia is notknown, but it has been estimated that up to 30% of thosewith arterial reconstructions will develop this complica-tion The lesion will nearly always develop during the firstyear following the therapy The other common cause offailure of many reconstructions is disease progression.This can occur either proximal or distal to the site oftherapy

com-Until recently, it was not common practice to followpatients prospectively after surgery, but rather to simplyawait the appearance of new symptoms This was notproper, as we now know from the prospective studies thathave been done Regular surveillance of the reconstruc-tion appears to be very important, particularly for veingrafts, to detect new lesions before thrombosis occurs.Surveillance permits early correction of the complicationwith prolongation of the life of the graft (43,44)

For vein grafts, the most suitable method of follow-uphas been color Doppler ultrasound with real-time spectralanalysis This permits a complete survey of the graft in-

20 Part I Imaging Techniques

eluding the inflow and outflow arteries as well The

crite-ria that have been developed relate to the extent of the

de-gree of stenosis and the peak systolic velocity in the graft

itself, which can also reflect changes in both the inflow and

outflow from the graft Although the criteria used by

dif-ferent investigators have varied somewhat, the following

guidelines would appear to work well for follow-up

pur-poses

Arterial Inflow Most of the grafts being followed have

their origin from the common femoral artery, but some

will be placed at a lower level, depending on the extent of

the occlusive disease Regardless of the site of origin, there

are velocity criteria that can provide information that

is useful These are as follows: a triphasic waveform

(forward-reverse-forward flow) This is reassuring that

inflow to that point is adequate The finding of a

monophasic waveform at any point proximal to the origin

of a vein graft is certain evidence that there is proximal

dis-ease that is hemodynamically significant If one desires to

further scan the inflow to localize the site of involvement

and estimate its significance, the procedure as described

earlier in this chapter should be followed

The Vein Graft Before beginning the scanning

proce-dure, the examiner must be aware of the type of graft used

(in situ versus reversed) With the in situ graft, the

proxi-mal portion of the graft is larger, and the opposite is found

with the reversed graft With the in situ graft the peak

sys-tolic velocities will increase as one approaches the distal

anastomosis; the opposite will be seen with the reversed

vein graft There are several points to consider in

deter-mining how well a graft is functioning The areas that are

of specific interest are as follows:

First is the proximal anastomosis The geometry of an

end-side anastomosis is complex It is impossible to

pro-vide firm guidelines to be used with regard to absolute

values for peak systolic and end-diastolic velocities across

such unions However, because follow-up studies permit

comparisons from one visit to another, it is possible to

document the development of an anastomotic stenosis

when changes are found

Second is the vein graft itself Problems can also

de-velop at sites of valve cusps (4,5) Most myointimal

le-sions are generally very well localized, as noted in Fig

2.14 These discrete areas will produce changes in peak

systolic velocity, the magnitude of which depends on the

degree of diameter reduction Arteriovenous fistulas may

also be present in the in situ graft and are easily recognized

by the very high end-diastolic velocities recorded

proxi-mal to the fistula The findings during follow-up that are

important can be summarized as follows

The velocities in a graft without any obvious sites of

narrowing will be dependent upon several variables

including the size of the vein graft and the nature of the

outflow Low velocities (<45cm/s) can be found in an

otherwise normal graft, particularly if the graft is large

(6mm or greater) However, if velocities below 45cm/s

FIGURE 2.14 This B-mode picture is of a stenotic lesion

in a vein graft that developed secondary to mal hyperplasia Arrows indicate site of lesion

myointi-are seen in a vein graft without any obvious sites of sis, then it is either secondary to an inflow or outflowproblem

steno-For velocities at sites of narrowing within the body ofthe graft, the problem is not in detecting the site of nar-rowing, but in estimating its severity and, most impor-tantly, its present and future effect on graft function If thelesion narrows the graft by more than 50%, it will mostlikely lead to a fall in distal pressure and flow, which couldcompromise graft function The problem is further com-plicated by trying to predict on the basis of diameter re-duction which grafts will thrombose if left alone This is,

of course, the most important issue because vein graft tency, along with preservation of function, is the majorgoal of a surveillance program

pa-The efforts in this regard have been led by Bandyk(43,44), followed by others who have carried out similarsurveillance programs in an attempt to detect those le-sions that need prompt intervention in contrast to thosethat can be safely followed While there are some differ-ences in the end points used for intervention, the pub-lished studies have in general shown an improvement inassisted primary patency of the vein grafts by institutingsuch a program Bandyk has proposed that the indicationsfor graft revision be based on the severity of the hemody-namic impairment of the graft rather than the duplex scanfindings alone (40,41) He has recommended graft revi-sion for the following situations: 1) a low peak systolic ve-locity (<45cm/s) in the distal graft; 2) a decrease in peaksystolic velocity of more than 30cm/s associated with adecrease in the AAI of more than 0.15; and 3) a cor-rectable lesion within the vein graft Bandyk's programhas achieved an assisted primary patency rate of 85% at 2years by following this protocol

Idu et al., in a prospective study of 201 vein grafts,

re-ported that for 58 grafts with stenotic graft lesions that

were not treated, the following outcome was noted (45):

none of the grafts with a 30% to 49% diameter reduction

failed; occlusion occurred in 57% of the non-revised

grafts with a 50% to 69% diameter reduction, as

com-pared with only 90% of the revised grafts; and grafts with

a 70% to 99% stenosis all failed if not treated, as

com-pared with 10% for the revised grafts By following such a

protocol, the primary assisted patency at 48 to 60 months

for grafts with lesions not treated at the time of detection

was 72% In contrast, for those in which intervention was

performed, the rate during the same time interval was

ooo/

oo /o.

Mattos et al., over a 39-month period, studied 170

limbs with vein grafts (46) These grafts were studied at 3,

6, and 12 months and then yearly There were 110

stenoses detected in 62 (36%) of the vein grafts Of these

stenoses, 27% were at anastomoses and 65% were in the

graft itself A total of 77% were detected within the first

year Of this group, 39% of the grafts with lesions were

re-vised For those grafts with negative scans, the primary

patency was 90% at 1 year and 83% at 2 to 4 years In

contrast, the patency rates with grafts that had a stenosis

of more than 50% diameter reduction that were not

cor-rected, the patency was 66% at 1 year and 57% for years

2 through 4 Mattos et al concluded that color duplex

scanning was effective in detecting those lesions of more

than 50% diameter reduction, which were associated

with a high failure rate (46) The criterion for detecting

such a stenosis in a vein graft was finding a peak systolic

velocity ratio of 2 The ratio is the peak systolic velocity in

the stenosis divided by that recorded just proximal to the

stenosis

Our studies are quite similar to the above We have

noted that duplex scan velocity measurements are valid

predictors of impending graft stenosis The best

predic-tors of outcome were a velocity ratio of 3.5 or more and a

mean graft velocity of <50 cm/s We recommend repair of

correctable graft lesions that fall into this category Grafts

that do not have detectable lesions in the inflow, the graft

or outflow regardless of the mean graft velocity may be

safely followed (47-50) Most of the changes that require

revision will develop within the first few months but the

surveillance program must still be followed The time

in-tervals for study vary somewhat from center to center but

are most frequent in the first year If the graft remains

patent without problems at one year, the intervals of study

can be every 6 months If a new problem develops at any

time the follow-up interval will have to be shortened to

document the stability of the lesion

The Visceral Arteries

With the availability of low-frequency transducers, it has

become possible to study flow in the hepatoportal

circula-tion, the mesenteric arteries and the renal arteries From

the standpoint of the vascular surgeon, these have become

important as methods of screening and follow-up after tervention, be it surgical or endovascular

in-Mesenteric CirculationThe two most common events involving the mesentericcirculation are acute mesenteric ischemia and mesentericangina In the case of acute ischemia with occlusion of thesuperior mesenteric artery, the clinical presentation andurgency for a prompt diagnosis are such that duplex scan-ning has a small role to play The success of the outcomedepends upon the rapidity with which therapy is applied

to prevent bowel necrosis, which is associated with a veryhigh mortality rate

Chronic mesenteric ischemia is often difficult to nose Although the clinical presentation of fear of foodbecause it produces abdominal pain and diarrhea accom-panied by marked weight loss is typical for the syndrome,the symptoms are often not specific Often other causesfor the symptom complex need to be sorted out Prior tothe availability of duplex scanning, aortography with lat-eral views of the celiac and superior mesenteric arterieswas the only method of establishing with certainty the in-volvement of these arteries, which is required for the syn-drome to develop

diag-It is now well known that all three of the maj or arteriessupplying the small bowel must be involved for this syn-drome to develop This is because the collateral circulationthat can develop is normally very extensive For example,

it is possible for the celiac and superior mesenteric arteries

to be totally occluded yet the blood supply to thesmall bowel be entirely normal via the inferior mesentericartery

Thus, in theory if duplex scanning is to play adiagnostic role, it should be used to investigate allthree sources of blood supply to the small bowel.Until recently, most attention has been paid to theceliac and superior mesenteric arteries (51-55) Theinferior mesenteric artery, owing to its size and location,has been more difficult to study, but this is now alsopossible

The guidelines that have been used for the diagnosis

of chronic mesenteric ischemia have evolved to includethe following (53,54)

1 The criteria used are based on changes in the peak tolic velocity

sys-2 The normal peak systolic velocities in the abdominalaorta in the region of the origins of the celiac andsuperior mesenteric arteries are in the range of

100 ±20 cm/s

3 As the sample volume of the pulsed Doppler is movedfrom the aorta to the first portion of the celiac and su-perior mesenteric arteries, the peak systolic velocitywill increase

4 To establish the normal range for the detected ties, Moneta et al studied 100 patients with lateralaortograms as a part of a workup for peripheral arte-rial disease (54)