Dynamic curvature strongly affects wall shear rates in a coronary artery bifurcation model.

This study was motivated by the need for a better understanding of coronary artery blood flow patterns and their possible role in atherosclerosis formation. Of particular interest in this study was the effects of the dynamic deformation due to myocardial contraction on wall shear rate patterns in the coronary arteries. A better understanding of these effects on wall shear rate in a bifurcation geometry and an evaluation of the importance of these effects was desired. A three-dimensional computer model of a bifurcation lying on the surface of a sphere with time-varying radius of curvature was employed to simulate the motion and deformation of the arteries. The results indicated low mean shear rates along the myocardial wall and very high shear rate variations (over 100% of the static mean shear rate) along the outer wall. The results obtained using a quasi-static analysis were found to underestimate the dynamic wall shear rate variation along the myocardial and outer walls. It was concluded that dynamic geometry effects are important in determining sites of low mean and oscillating wall shear that have been associated with atherogenesis in curved, bifurcating arteries.