Abstract 685: Atherosclerotic Plaque Composition Among patients with Stenotic Coronary Artery Disease on Non Invasive Coronary CT Angiography

Abstract

Coronary CT angiography (CCTA) has emerged as a promising non-invasive tool to rule out significant coronary artery disease (CAD) as well provides additional information about atherosclerotic plaque composition. In this study we aim to assess the whether differences in plaque composition exist across patients with varying degree of stenotic CAD disease. The study population consisted of 548 subjects (58±11 years, 45% women) referred for 64-slice multi-detector CCTA for assessment of underlying degree of coronary artery disease. We analyzed plaque characteristics on a per-segment basis according to the modified AHA classification. Plaques types were classified as non-calcified, calcified, mixed type 1 (predominantly non-calcified) or mixed type 2 (predominantly non-calcified). Overall 194 (35%) had normal coronaries without evidence of plaque. In the remaining 354 patients, 187 (34%) and 167 (31%) were found to have luminal narrowing of <50% and ≥70% in at-least one coronary artery segment, respectively. Those with a higher degree of stenotic CAD demonstrated significantly more coronary segments with exclusively calcified and mixed plaques (table ). Among those with significant CAD, the overall proportion of plaque burden was more likely to be mixed predominantly calcified (18% vs. 38% vs. 44%) as well as mixed predominantly non-calcified in nature; whereas were less likely to be exclusively non-calcified (39% vs. 20% vs. 16%). Only 3/208 (1.3%) patients without any underlying calcification had significant CAD (stenosis ≥50%). In summary, significant differences in plaque composition according to severity of CAD were observed in our study with a higher mixed plaque and lesser non-calcified plaque burden among those with stenotic CAD. These findings should stimulate further investigations to assess the prognostic value of plaque according to their underlying composition.