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Intravascular Ultrasound Pocket Guide
Seventh Edition
Robert J. Russo, MD, PhD Director, Intravascular Imaging Program Director, Cardiac MRI Program Scripps Clinic La Jolla, CA
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[email protected]. Copyright © 2011 by Jones and Bartlett Publishers, LLC All rights reserved. No part of the material protected by this copyright may be reproduced or utilized in any form, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission from the copyright owner. The authors, editor, and publisher have made every effort to provide accurate information. However, they are not responsible for errors, omissions, or for any outcomes related to the use of the contents of this book and take no responsibility for the use of the products and procedures described. Treatments and side effects described in this book may not be applicable to all people; likewise, some people may require a dose or experience a side effect that is not described herein. Drugs and medical devices are discussed that may have limited availability controlled by the Food and Drug Administration (FDA) for use only in a research study or clinical trial. Research, clinical practice, and government regulations often change the accepted standard in this field. When consideration is being given to use of any drug in the clinical setting, the healthcare provider or reader is responsible for determining FDA status of the drug, reading the package insert, and reviewing prescribing information for the most up-to-date recommendations on dose, precautions, and contraindications, and determining the appropriate usage for the product. This is especially important in the case of drugs that are new or seldom used. It is our purpose to promote an understanding of intravascular ultrasound and to review examples where IVUS imaging may be helpful in diagnostic and interventional applications. Production Credits Senior Acquisitions Editor: Alison Hankey Senior Editorial Assistant: Jessica Acox Production Director: Amy Rose Associate Production Editor: Laura Almozara Senior Marketing Manager: Barb Bartoszek V.P., Manufacturing and Inventory Control: Therese Connell
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Library of Congress Cataloging-in-Publication Data Russo, Robert J. Intravascular ultrasound pocket guide / Robert J. Russo. — 7th ed. p. ; cm. Includes bibliographical references and index. ISBN-13: 978-0-7637-6600-9 ISBN-10: 0-7637-6600-3 1. Blood-vessels—Ultrasonic imaging—Handbooks, manuals, etc. 2. Intravascular ultrasonography—Handbooks, manuals, etc. I. Title. [DNLM: 1. Vascular Diseases—ultrasonography—Handbooks. 2. Image Processing, Computer-Assisted—methods—Handbooks. WG 39 R969i 2011] RC691.6.U47R87 2011 616.1´307543—dc22 2009045695 6048 Printed in Canada
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Dedication To Sophia Grace and Isabella Rose
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Table of Contents Acknowledgments ................................................ vii Part I: Imaging Anatomy ............................................................................... 1 Pathology............................................................................ 15 Calcium .............................................................................. 31 Stent................................................................................... 41 Complications ..................................................................... 56 Peripheral Images ............................................................... 69 Artifacts .............................................................................. 74
Part II: Application Guideline Update ................................................................ 81 IVUS Coding ....................................................................... 83 IVUS Coding—Outpatient .............................................. 83 IVUS Coding—Physician Payment................................. 84 IVUS Catheters ................................................................... 85 IVUS Catheters—Coronary Imaging ............................... 85 IVUS Catheters—Peripheral Imaging ............................. 86 Clinical Trials....................................................................... 87 Clinical Trial—RESIST ................................................... 87 Clinical Trial—CRUISE .................................................. 88 Clinical Trial—OPTICUS ................................................ 89 Clinical Trial—TULIP ..................................................... 90 Clinical Trial—AVID ....................................................... 91 IVUS Criteria ....................................................................... 92 IVUS Criteria Bare-Metal Stent Placement—MUSIC ....... 92 IVUS Criteria Bare-Metal Stent Placement—AVID........... 93 IVUS Criteria Drug-Eluting Stent—PRAVIO/AVIO ............ 94 IVUS Criteria—Left Main Stenosis—Abizaid AS, et al. ..... 95 IVUS Criteria—Left Main Stenosis—Fassa AA, et al. ....... 96 IVUS Criteria—Left Main Stenosis—Russo RJ, et al. ....... 97 IVUS Criteria—Left Main Stenosis—Sano K, et al. .......... 98 IVUS Criteria—Non-Left Main Stenosis —Abizaid AS, et al..................................................... 99 IVUS Criteria—Non-Left Main Stenosis —Nishioka T, et al. .................................................. 100
Index................................................................. 101
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Acknowledgments I would like to express my sincere gratitude to the many people at Scripps Clinic who assisted me with this handbook: Jennifer Lucisano for the seminal idea and the inspiration to publish a reference work of images in a handbook format; Heather Costa for her endless enthusiasm in the preparation of the present edition; Patricia Silva for her unequaled editing skills; Richard Schatz, Paul Teirstein, Dave Kanzari, Curtiss Stinis, and Matt Price, in addition to countless fellows in Interventional Cardiology at Scripps Clinic over the past decade who have tolerated my many requests for IVUS evaluation; and the very benevolent and patient editors at Jones and Bartlett.
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Part I: Imaging
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ANATOMY
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IVUS Sampler Guidewire
Calcium
Intima
Calcium Shadow Media
Plaque Guidewire Artifact
Adventitia
Septal Branch
Example of intravascular ultrasound imaging with a 30-MHz catheter in the mid portion of the LAD. Note blood artifact within the lumen and the crescent-shaped eccentric fibrocalcific plaque in the right upper quadrant of the artery.
Anatomy
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Three-Layer Appearance ANATOMY
IVUS of an angiographically normal segment of the distal left main coronary artery shows all three layers of a muscular artery. Moderate, circumferential intimal thickening of intermediate echogenicity is consistent with fibrous plaque. The medial layer (internal elastic lamina, smooth muscle, and external elastic lamina) is seen as a distinct, circumferential, echolucent (black) zone or structure. The outermost layer, the adventitia (comprised of collagen and elastic fibers), is seen as a circumferential, echo-bright layer surrounding the vessel and separating it from myocardium. (Note: In the absence of calcium, the adventitia represents the brightest vascular structure within the image.)
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PART I Imaging
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ANATOMY
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Measurements
Vessel cross-sectional area (CSA) is obtained by tracing the border between the hypoechoic media and hyperechoic adventitia (dashed line). Lumen area is measured by tracing the lumen-intima interface (dotted line). The lumen diameter is obtained by determining the smallest diameter that passes through the geometric center of the lumen (vertical line with arrows). Note that all IVUS diameter measurements have both a minimal and maximal value. The proximal and distal reference segments are defined as the most normal appearing vessel within a 10-mm segment proximal or distal to the lesion. Diameter stenosis is calculated as (reference lumen diameter – minimum lumen diameter) divided by reference lumen diameter. Plaque area is plaque+media CSA, which can be calculated by subtracting the vessel lumen CSA from the arterial CSA.
Anatomy
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Pericardium ANATOMY
Diagnostic IVUS imaging was performed in the distal portion of a large-caliber ramus intermedius. The vessel measures 1.75 mm (media-to-media) with minimal intimal thickening. In the lower left quadrant the echolucent ventricular cavity is seen. A band of myocardium (~1.5 mm) extends from the upper left to lower right portion of the image and contains the arterial lumen. On the superior edge of myocardium, the epicardial surface and visceral pericardium are identified. The echolucent pericardial space separates the visceral and parietal pericardial layers.
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PART I Imaging
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ANATOMY
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Normal SVG
IVUS imaging in an angiographically normal segment of a saphenous vein graft (SVG) shows minimal circumferential intimal thickening of a fibrous quality. Mediastinal fibrous tissue has engulfed the vessel as a result of wound healing. A horizontal, echolucent interface most likely represents a pericardial reflection or epicardial surface. (Note: Although a three-layer appearance may be appreciated, a saphenous vein does not contain a true adventitial layer, and, when compared to a muscular epicardial coronary artery, elastic and smooth muscle layers of the medial are significantly less prominent.)
Anatomy
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Vein Graft Anastomosis ANATOMY
Angiographic views failed to adequately visualize a lesion at the anastomosis of an SVG to the distal RCA. Ultrasound was performed within the anastomosis. On the left, the lumen of the vein graft can be seen, with modest thickening of the intimal layer. Blood echoes fill the lumen. On the right, the threelayer appearance of the native artery can be seen. Significant plaque is noted, with an intermediate or fibrous to fibrocalcific echoreflective quality. Due to the unusual plane of the imaging catheter, both vessels are viewed tangentially.
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PART I Imaging
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ANATOMY
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Vein Graft Valve
By angiography, a discrete, eccentric, 50% stenosis was noted in the mid-portion of an SVG. Differential angiographic diagnosis included eccentric plaque, dissection, and vein graft valve. IVUS imaging revealed mildly calcified, immobile leaflets of a vein graft valve, resulting in a 50% cross-sectional area stenosis. No other vascular pathology was visualized.
Anatomy
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Epicardial Vein ANATOMY
Pre-procedure IVUS imaging was performed in an angiographically normal portion of the mid-RCA. An eccentric vessel lumen measures 2.2 x 2.5 mm. A guidewire artifact with far-field shadowing is noted in the inferior portion of the image. The lumen of a branch vessel, septal, is also seen in the bottom of the image. Coursing over the artery in a circumferential path on the epicardial side is a cardiac vein. The vein is a thin-walled structure of 1-mm diameter. Unlike arteries, cardiac veins do not demonstrate a three-layer appearance. The identity of the vein can be confirmed by following its course to be assured that it does not communicate with the adjacent artery.
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PART I Imaging
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ANATOMY
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Cardiac Vein
Diagnostic IVUS was performed in the proximal portion of a medium-caliber left circumflex coronary artery. The vessel measures 3.1 mm (media-to-media) with minimal circumferential intimal thickening. In the upper left portion of the image, adjacent to the artery, a thin-walled, echolucent cardiac vein is noted. This venous structure (coronary sinus) lacks the three-layer appearance of the epicardial muscular artery.
Anatomy
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Coronary Sinus ANATOMY
Diagnostic IVUS was performed using automatic pullback in a medium- to small-caliber, non-dominant left circumflex coronary artery. Imaging was obtained from the distal vessel to the ostium. The vessel measures 2.5 mm (media-to-media) with eccentric calcified plaque noted at 12 o’clock. Superficial calcium is noted within the lesion with far-field shadowing. In the bottom portion of the image, a large echolucent space of 3 x 7 mm is noted, which represents the coronary sinus. This venous structure (coronary sinus) lacks the three-layer appearance of the epicardial muscular artery.
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ANATOMY
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Extra-Vascular Space
Diagnostic IVUS was performed to assess an inconclusive lesion in a medium-caliber left main coronary artery. In the proximal portion of the vessel, prior to the left main-aortic junction, an echo-free space is noted. This non-vascular structure is a space bounded by the visceral and parietal pericardial layers and is often seen during assessment of the left main coronary artery.
Anatomy 11
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Coronary Spasm ANATOMY
Diagnostic IVUS was performed to assess an intermediateto high-grade lesion in the mid-portion of the left anterior descending coronary artery. The vessel lumen measures 1.9 x 2.1 mm without significant intimal pathology (plaque). In addition, very prominent medial and adventitial layers are noted. When intracoronary nitroglycerin was administered, the lumen diameter increased and the angiographic stenosis resolved. The combination of a prominent, thickened media with minimal plaque is characteristic of a vessel segment where spontaneous coronary artery spasm may occur.
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ANATOMY
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Branch Vessels
Diagnostic IVUS was performed in the mid-portion of a medium caliber left anterior descending coronary artery to assess a lesion adjacent to the origin of a diagonal branch. The LAD measures 3.0 mm from media to media and contains mild superficial calcification. A diagonal branch is seen at 10 o’clock, and a septal branch is noted at 5 o’clock. The echolucent space in the lower left-hand portion of the image is the pericardial space. Although the branch vessels can be visualized, great care should be taken when evaluating for ostial disease.
Anatomy 13
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Contrast Flush ANATOMY
Diagnostic IVUS was performed in the distal portion of the left main coronary artery prior to elective stent placement. Superficial calcification was noted, however, the luminal dimensions could not be accurately measured. To clear the blood echoes and accurately define the luminal border, a small bolus of contrast was administered through the guide catheter. When the blood signal is removed from the image in a contrast-filled vessel, the lumen border is easily identified and accurate measurements can be made. Nonagitated saline can also be used, but contrast yields a more consistent image.
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PATHOLOGY
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Transplant Atherosclerosis
Diagnostic IVUS was performed in the proximal LAD in a patient with a history of cardiac transplantation 8 years prior. IVUS imaging reveals a vessel diameter (media-to-media) of 6.0 mm (probably the result of positive compensatory remodeling). The lumen diameter measures 2.25 mm with a lumen area of 4.0 mm2. Circumferential, bulky intimal thickening is noted (1.0 to 1.75 mm) with a fibrous appearance with microcalcification that is typical of transplant vasculopathy. Diffuse microcalcification is seen in the mid-portion of the plaque layer, between 12 and 3 o’clock.
Pathology 15
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Lipid-Laden Plaque
PATHOLOGY
This patient was a well-trained aerobic athlete. One week after a non-Q-wave MI, a 50% angiographic stenosis was seen in the mid-portion of the LAD. Diagnostic ultrasound demonstrated an 80% relative cross-sectional area stenosis when compared to the distal reference vessel lumen. The media-to-media distance of 5.5 mm may appear to represent the early stage of vascular remodeling. However, the distal vessel was of similar size without plaque. This large plaque mass has a heterogenous appearance. Intermediate echogenecity at 5 o’clock resembles necrotic or lipid-rich plaque. Guidewire artifact is seen at 3 o’clock.
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PATHOLOGY
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Ulcerated Plaque
Diagnostic IVUS was performed in the left main coronary artery after an acute myocardial infarction and primary balloon angioplasty. In this image the distal portion of the left main measures 5.0 x 5.6 mm (media-to-media). The lumen measures 2.2 x 4.0 mm. A large amount of plaque is noted with dense, superficial calcium (and far-field shadowing) in the right lower quadrant. At one o’clock, a disruption is noted in the luminal contour with ulceration extending deep into the plaque layer. This ulcerated plaque may have been the culprit triggering the anterior infarction.
Pathology 17
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Blood Stasis
PATHOLOGY
A stent was placed in the distal portion of a large-caliber right coronary artery. By angiography, a distal, contraststaining dissection was noted. Ultrasound reveals a bright echo-reflective area in the right lower quadrant of the vessel, representing acute blood stasis. Thrombus may appear as either an echolucent or mildly echoreflective structure with an irregular border within the lumen. Static blood, however, has a highly reflective appearance, similar in intensity to calcium or a metallic stent.
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PATHOLOGY
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Complicated Left Main Plaque
Due to a hazy appearance of the left main ostium, diagnostic intravascular ultrasound was performed. IVUS shows the superior portion of the left main ostium at the top of the image, while aortic blood is seen at the bottom. Moderate superficial calcification is noted. Because the imaging catheter exits the left main with a cranially-directed, non-coaxial path, the tomographic ultrasound plane includes the superior wall of the left main coronary ostium, but not the inferior wall. For the appropriate measurement of ostial left main stenosis, the catheter must be placed in a coaxial position and images obtained that include a circumferential appearance of the lumen.
Pathology 19
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Pericardium and Eccentric Plaque
PATHOLOGY
Diagnostic IVUS was performed in the mid-portion of the left anterior descending coronary artery to evaluate an inconclusive lesion by angiography. The vessel measured 4 mm from media to media, with a lumen diameter of 2.0 x 3.0 mm. Minimum cross-sectional area at the lesion was 4.9 mm2, which represented a relative 60% area stenosis when compared to a distal reference segment without significant plaque. The pericardial space is noted in the lower right-hand quadrant of the image. Superficial calcium is noted with significant far-field shadowing in the upper lefthand quadrant. Plaque deposit is eccentric with pericardial accumulation greater than myocardial.
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PATHOLOGY
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Thrombus 1
Diagnostic IVUS was performed within the left circumflex coronary artery to assess the results of circumflex coronary stent placement. IVUS demonstrated a large mobile structure (left-hand side of the image extending from 7 to 11 o’clock) with intermediate and homogeneous echo intensity. This angiographically occult finding by IVUS represents dissection at the proximal stent edge with discontinuity noted at 11 o’clock. In addition, deep calcification is noted on the left side of the image. The stiff, calcified wall may have provided resistance to stent balloon expansion compared to the more compliant adjacent vessel wall. Thus the interface between calcium and compliant vessel is a point of dissection.
Pathology 21
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Heterogenous Plaque
PATHOLOGY
Diagnostic IVUS was performed in the mid to distal portion of the left anterior descending coronary artery to assess an inconclusive lesion. The vessel measures 3.5 mm from media to media. The lumen measures 1.8 x 2.0 mm with a cross-sectional area of 2.8 mm2 and a relative cross-sectional area of stenosis of 71%. The intermediate echo intensity of the plaque is consistent with fibrocalcific disease with micro-calcification noted throughout the lesion. A collection of dense, deep calcification is noted at 8 o’clock with minimal far-field shadowing.
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PATHOLOGY
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Circumferential Calcification
Penetration of the ultrasound beam at 40 MHz is dependent upon the presence of calcification, previous stent placement, vessel size, and volume of plaque burden. All decrease the penetration of ultrasound. Diagnostic IVUS was performed to assess an intermediate eccentric lesion by angiography. The IVUS image demonstrates a lumen 1.6 x 2.4 mm with a cross-sectional area of 3.0 mm2. Significant diffuse microcalcification is noted with far-field shadowing. The smallest plaque burden is noted between 7–9 o’clock with identification of the media and acceptable far-field penetration. However, this image does not allow for identification of the media or measurement of vessel area.
Pathology 23
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Complex Thrombus
PATHOLOGY
This patient experienced an acute inferior wall infarction treated with thrombectomy and placement of a bare metal stent. Two days later, the patient experienced reocclusion of the RCA. After infusion of a IIb/IIIa inhibitor and repeat thrombectomy, IVUS was performed. The image shows a vessel diameter (media to media) of 5.0 mm, a lumen diameter of 2.3 x 2.8 mm with an irregular luminal surface. A guidewire artifact is noted at 1 o’clock. The vessel lumen is filled with a homogeneous ultrasound signal of intermediate echogenicity which cleared after further thrombectomy and is consistent with interluminal thrombus. Note channels within the thrombus at 6 and 8 o’clock.
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PATHOLOGY
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Protruding Plaque
Pre-stent placement IVUS was performed to assess an area of angiographic “haziness” in the mid-portion of the left main. IVUS reveals a lumen diameter of 3.4 mm and a vessel diameter of 4.0 mm. Guidewire artifact is seen at 10 o’clock. A very eccentric plaque with a dense superficial calcification is noted protruding into the vessel lumen at 9 o’clock. The proximity of the calcified plaque to the imaging catheter creates a large far-field shadow obscuring most of the vessel anatomy on the left side of the image. This type of plaque appearance is worrisome as guiding catheters and balloons/stents may create a dissection plane at this location.
Pathology 25
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High-Grade Lesion
PATHOLOGY
Diagnostic IVUS was performed within the mid-portion of the left anterior descending coronary artery to assess an inconclusive angiographic lesion. The vessel measures 3.6 mm (media-to-media). The vessel lumen measures 1.5 x 1.5 mm with a cross-sectional area of 1.8 mm2. This represents an 84% cross-sectional area stenosis. Cross-sectional area lesion severity of greater than 75% is unusual by IVUS and requires a residual lumen not much larger than the imaging catheter and a distal reference vessel of 3.5 mm or greater. The echolucent zone at 11 o’clock represents a guidewire shadow.
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PATHOLOGY
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Thrombus 2
This patient with acute anterior wall myocardial infarction underwent IVUS to identify the culprit lesion within a diffusely diseased LAD. This image shows a vessel diameter of 4.3 x 4.9 mm (CSA of 16.5 mm2). The lumen measures 1.5 x 2.0 mm (CSA exclusive of thrombus 2.3 mm2; inclusive of thrombus 4.7 mm2). Thick circumferential fibrous plaque is seen. In the lumen surrounding the imaging catheter, a low intensity is noted consistent with luminal thrombus. At 4–5 o’clock a channel is noted in the thrombus, which is laminated upon superficial calcification. IVUS was used not only to identify the culprit lesion but also to determine the appropriate size of balloon and stent.
Pathology 27
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Ulcerated Plaque 2
PATHOLOGY
Diagnostic IVUS was performed within the mid-portion of the right coronary artery to assess an inconclusive angiographic lesion. This image shows a vessel diameter of 4.5 mm (media-to-media). The eccentric lumen measures 2.2 x 3.3 mm in diameter. A superficial defect or ulceration is noted in the fibrocalcific eccentric plaque at 9 o’clock. Guidewire artifact is seen at 2 o’clock.
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PATHOLOGY
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Eccentric Complicated Plaque
A patient with unstable coronary symptoms underwent diagnostic angiography. IVUS was performed to evaluate an eccentric lesion in the proximal part of the LAD. The image demonstrates very eccentric plaque deposition. A small superficial ulcer is seen at 9 o’clock. The vessel measures 3.2 x 4.3 mm in diameter with a cross-sectional area of 11.2 mm2. The residual lumen measures 1.8 x 2.4 mm2 with a crosssectional area of 3.3 mm2 and an absolute cross-sectional area stenosis of 71%. Two areas of low image intensity are noted at 8 and 10 o’clock in the mid-portion of the plaque, and most likely represent lipid deposition. Thus, this image is consistent with unstable coronary syndrome.
Pathology 29
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Vulnerable Plaque
PATHOLOGY
After an inconclusive angiogram, this patient with crescendo symptoms and an abnormal CT angiogram underwent IVUS evaluation of the LAD. This image of the left main demonstrates a vessel diameter of 4.0 x 4.8 mm (CSA of 14.5 mm2). The lumen measures 2.7 x 3.7 mm (CSA of 8.4 mm2). Heterogenous, eccentric fibrocalcific plaque is noted between 3 and 7 o’clock. At 4 o’clock a thin cap of superficial calcium is noted superficial to a deeper echolucent area consistent with a lipid-rich or necrotic core. This has the appearance of a vulnerable plaque. However, the definition of a thin-cap fibroatheroma (TCFA) or vulnerable plaque is superficial calcium of 9.0 mm2. In-stent minimal lumen area ≥80% of the average reference lumen area or ≥90% of lumen area of the reference segment with the lowest lumen area. In-stent lumen area of proximal stent entrance ≥90% of proximal reference lumen area. 3. Symmetric stent expansion defined by minimum lumen diameter/maximum lumen diameter (LDmin/LDmax) ≥0.7.
IVUS CRITERIA
de Jaegere P, Mudra H, Figulla H, et al. Intravascular ultrasound-guided optimized stent deployment. Immediate and 6-month clinical and angiographic results from the Multicenter Ultrasound Stenting in Coronaries Study (MUSIC Study). Eur Heart J. 1998;19(8):1214–1223.
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Bare-Metal Stent Placement
AVID (Angiography versus intravascular ultrasound-directed stent placement) IVUS criteria for optimal stent expansion a. The smallest cross-sectional area (minimal stent area) within the stent should be 90% of the distal reference lumen cross-sectional area. b. Full apposition of the stent to vessel wall must be observed. c. Dissections involving exposure of the media or deep wall elements of an SVG must be covered by subsequent stent placement. The distal reference vessel selected for comparison of CSA should be a normal section of vessel within 5 mm of the distal stent edge.
Russo RJ, Silva PD, Teirstein PS, et al. A randomized controlled trial of angiography versus intravascular ultrasound-directed bare-metal coronary stent placement (The AVID Trial). Circ Cardiovasc Intervent. 2009;2: 113–123.
IVUS CRITERIA
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IVUS Criteria
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IVUS Criteria Drug-Eluting Stent (DES)
PRAVIO/AVIO (Preliminary investigation to the angiographic versus IVUS optimization) IVUS criteria for optimal DES expansion Based upon a single center study of 113 complex lesions. a. IVUS is performed after DES implantation. b. Minimum and maximum media-to-media diameters of the vessel are measured at the proximal, mid, and distal portion of the stented lesion. c. The media-to-media diameters are averaged to determine the diameter of the post-dilating balloon (rounded to the nearest 0.5 mm). d. The cross-sectional area (CSA) of the post-dilating noncompliant balloon is calculated (CSA=πr2) and no overexpansion is assumed. e. Optimal stent expansion is defined as a minimal stent CSA >70% of the CSA of the post-dilating balloon.
IVUS CRITERIA
Gerber RT, Latib A, Ielasi A, et al. Defining a new standard for IVUS optimized drug eluting stent implantation: The PRAVIO study. Catheter Cardiovasc Interv. 2009;74:348-356.
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Left Main Stenosis (Abizaid AS, et al., 1999) The purpose of this study was to correlate angiographic and intravascular ultrasound (IVUS) findings in left main coronary artery (LMCA) disease and identify the predictors of coronary events at one year in patients with LMCA stenoses. One hundred twenty-two patients who underwent angiographic and IVUS assessment of the severity of LMCA disease and who did not have subsequent catheter or surgical intervention were followed for one year. Standard clinical, angiographic and IVUS parameters were collected. There was a poor correlation between QCA and IVUS in the assessment of reference segment and lesion site lumen dimensions. Core laboratory measurement of angiographic stenosis in the patients with an adverse event during the first year was 44% and 42% in the patients with and without an adverse event, respectively. Univariate predictors (P50%. In addition, IVUS predictors of patients (n=18) who experienced an adverse event within one-year included reference plaque burden, lesion lumen area (6.8 mm2), MLD (2.3 mm), plaque area (15.7 mm2) and relative (70%) and absolute area stenosis (52%).
Abizaid AS, Mintz GS, Abizaid A, et al. One-year follow-up after intravascular ultrasound assessment of moderate left main coronary artery disease in patients with ambiguous angiograms. J Am Coll Cardiol. 1999;34(3): 707–715.
IVUS CRITERIA
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IVUS Criteria
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IVUS Criteria Left Main Stenosis (Fassa AA, et al., 2005) The purpose of this study was to evaluate the efficacy of an IVUS-guided assessment strategy for patients with angiographically indeterminate left main coronary artery (LMCA) disease. IVUS was performed on 121 patients with angiographically normal left main coronary arteries, and the lower range of normal minimum lumen area (MLA) determined to be 7.5 mm2. Of 214 patients with angiographically indeterminate LMCAs, 38.8% had MLA
