Blood flow in S-shaped in-plane and out-of-plane coronary arteries

Abstract

The distribution of wall shear stress (WSS) in coronary arteries is an initiating factor for coronary artery disease. The complicated three dimensional structure of coronary arteries makes it difficult to isolate the factors affecting WSS distributions. Here we present a computational fluid dynamics study of transient flow in simplified S-shaped arteries with in-plane and out-of-plane bends. For in-plane arteries there are two regions of consistently low WSS during the cardiac cycle. The WSS distribution is related to secondary velocities which appear as symmetric counter-rotating eddies and are approximately 8% of the axial velocity. For out-of-plane arteries the WSS distributions are similar, but the eddies are no longer symmetric with secondary velocities only 7% of the axial velocities. The symmetric velocity patterns produced by the in-plane model could only exist in a single bend, which limits the usefulness of this model. The results obtained give useful insights into the nature of blood flow in realistically shaped coronary arteries.