Relationship Between Coronary Artery Remodeling and Plaque Vulnerability

Abstract

Background — In vivo studies with intravascular ultrasound have shown that complex plaque anatomy and plaque rupture are more frequent in the presence of marked outward remodeling. A large lipid core and a high macrophage count are recognized histological markers for plaque vulnerability. The link between plaque vulnerability in terms of these markers and remodeling in coronary arteries has not been explored. Methods and Results — In 88 male subjects who died suddenly with coronary artery disease, 108 plaques were studied. The percent remodeling was calculated. Lesions with remodeling ≥0% were considered to have positive remodeling, and those in which remodeling was <0% were considered to have negative remodeling. Percent lipid core and macrophage count at the plaque were assessed. Of 108 plaque sites, 64 (59.2%) had undergone no remodeling or positive remodeling, and 44 (40.7%) had negative remodeling (vessel shrinkage). Lesions with positive remodeling, compared with lesions with vessel shrinkage, had a larger lipid core (percent mean lipid core was 39.0±21.0% versus 22.3±23.1%, respectively; P <0.0001) and a higher macrophage count (mean macrophage count was 15.6±12.3 versus 8.9±11.6, respectively; P =0.005). Conclusions — We have shown that coronary artery plaques with positive remodeling have a higher lipid content and macrophage count, both markers of plaque vulnerability. These results may explain why plaque rupture is often apparent at sites with only modest luminal stenoses (but marked positive remodeling).