Composition of atherosclerotic plaques in the four major epicardial coronary arteries in patients ≥ 90 years of age

The composition of atherosclerotic plaques in 733 five-mm segments of the 4 major (left main, legt anterior descending, left circumflex and right) epicardial coronary arteries of 18 patients ≥90 years of age was determined by computerized planimetric analysis. By analysis of all coronary segments of all patients >90, the plaques consisted primarily of fibrous tissue (87 ± 8%) with calcific deposits (7 ± 6%), pultaceous debris (5 ± 4%) and foam cells (1 ± 1%) occupying a much smaller percentage of plaque area. Analysis of composition according to the 4 degrees of luminal cross-sectional area narrowing revealed marked step-wise increases in pultaceous debris (from 0 ± 0% at 0 to 25% narrowing to 18 ± 22% at 76 to 100% narrowing, p = 0.0001) and calcific deposits (from 0 ± 0 to 10 ± 15%, p = 0.002), and decreases in fibrous tissue (from 99 ± 3 to 71 ± 23%, p = 0.0001) and area occupied by the media (from 35 ± 8 to 16 ± 8%, p = 0.0001). When the analysis was restricted to sections narrowed >75%, no significant differences were found in plaque components or medial area between patients with (11 patients) and without (7 patients) myocardial infarcts at necropsy.