Abstract 5197: Arterial Remodeling Determines the Local Hemodynamic Environment and Subsequent Progression of Coronary Atherosclerotic Plaques: A Serial, Natural History Intravascular Ultrasound Study

Abstract

Background Endothelial shear stress (ESS) is a critical determinant of plaque formation and arterial remodeling. Expansive remodeling is a feature of plaque vulnerability. Our purpose was to assess the role of remodeling and ESS in plaque progression throughout the natural history of atherosclerosis. Methods Intravascular ultrasound (IVUS)-based 3D reconstruction of all major coronary arteries (n=15) was performed in vivo at weeks 4, 11, 16, 23 and 36 in five diabetic, hyperlipidemic pigs. Each artery was divided into 3mm-long segments (n=304). We calculated ESS in all segments at all time points using computational fluid dynamics. Remodeling was characterized at all time points as excessive expansive, compensatory or constrictive. Plaque progression between consecutive time points was assessed by change of plaque area (ΔPlaque). Results The remodeling response to individual plaque formation changed substantially over time. Excessive expansive remodeling persistently developed in regions of very low ESS (Fig A ), further decreased the low ESS (p<0.05), and was associated with the most marked additional plaque growth (Fig B ). Compensatory and constrictive remodeling generally resulted in increase of local ESS, and in less pronounced plaque progression (Fig A, B ). Conclusions This study provides new insight into the role of remodeling as a determinant of plaque progression. Excessive expansive remodeling exacerbates the pro-atherogenic low ESS environment, and promotes subsequent plaque growth. In contrast, attenuation of the low ESS stimulus occurs in lesions that elicit a compensatory, or constrictive remodeling response, leading to relative plaque quiescence.