Intravascular ultrasound classification of atherosclerotic lesions according to American Heart Association recommendation

Background Intravascular ultrasound (IVUS) offers a new modality by which t o image the vessel wall in high resolution. The aim of the study was to cla ssify atherosclerotic lesions using IVUS according to American Heart Associ ation (AHA) recommendation. Methods IVUS was performed using a 20 or 30 MHz mechanically rotated cathet er in 190 patients (aged from 35 to 75 years, mean 59+/-9 years) who presen ted with suspicion of coronary artery disease based on clinical examination . Results Of the 190 patients, 49 (26%) (group A) were found to have normal o r nearly normal coronary arteries, whereas the other 141 (74%) (group B) ha d significant angiographic stenosis (> 50% luminal narrowing). IVUS image i nterpretation was based on the recommendation of the Committee on Vascular Lesions of the Council on Atherosclerosis (AHA). In group A, a total of 822 segments were evaluated with IVUS; 444 (54%) were found to have plaque for mation, Among these 444 segments. type II lesions were found in 145 (33%), type III lesions in 110 segments (25%), type IV and Va lesions in 169 segme nts (38%), and type Vb in 18 segments (4%). The severity of plaque area ste nosis increased from type II to IV, In group B, only the most stenotic segm ents (n=141) on angiography were selected for analysis. No significant diff erences were found among different lesion types with respect to the severit y of plaque area stenosis. Type Vb and Vc lesions presented mainly, but not exclusively, as stable angina, whereas type VI lesions presented mainly as unstable angina. Some patients (12%) with stable angina had complicated le sions (type VIa-VIc), Conclusions It is now possible to use intravascular ultrasound to classify atherosclerotic lesions according to the AHA recommendations that were base d on histological examination. Standardized reports of IVUS can now be base d on these recommendations. Even in angiographically normal coronary arteri es, advanced atherosclerotic lesions are found, explaining the potential ri sk of acute coronary syndromes in this group of patients. In patients with angiographically severe coronary disease, clinical symptoms correlate mainl y with plaque characteristics, rather than with the severity of stenosis. C oronary Artery Dis 10:489-499 (C) 1999 Lippincott Williams & Wilkins.