A computational study of flow in a compliant carotid bifurcation-stress phase angle correlation with shear stress.

The present study presents a three-dimensional, unsteady supercomputer simulation of the coupled fluid-solid interaction problem associated with flow through a compliant model of the bifurcation of the common carotid artery into the internal and external carotid arteries. The fluid wall shear stress (WSS) and solid circumferential stress/strain (CS) are computed and analyzed for the first time using the complex ratio of CS to WSS (CS/WSS). This analysis reveals a large negative phase angle between CS and WSS (stress phase angle--SPA) on the outer wall of the carotid sinus where atherosclerotic plaques are localized. This finding is consistent with other measurements and computations of the SPA in coronary arteries and the aortic bifurcation that show large negative SPA correlating with sites of plaque location and in vitro studies of endothelial cells showing that large negative SPA induces pro-atherogenic gene expression and metabolite release profiles.