The Importance of Fluid-Structure Interaction Simulation for Determining the Mechanical Stimuli of Endothelial Cells and the Atheroprone Regions in a Coronary Bifurcation

The function and morphology of endothelial cells (ECs) play a key role in atherosclerosis. The mechanical stimuli of ECs such as wall shear stress (WSS) and arterial wall strains greatly influence the function and morphology of these cells. The present article deals with computations of these stimuli for a 3D model of a healthy coronary artery bifurcation. The focus of the study is to propose an accurate method for computations of WSS and strains. Two approaches are considered. The coupled simultaneous simulation of arterial wall and blood flow called Fluid-Structure Interaction (FSI) simulation and decoupled one,which simulates each domain (fluid and solid domain) separately. The study demonstrates that the computed circumferential strain resulting from both methods are identical. However, longitudinal strain and WSS are very different from these two approaches. The resulting time averaged wall shear stress (TAWSS) from decoupled fluid model is always higher than corresponding value from FSI simulation. While, oscillatory shear index (OSI) from rigid wall model is lower than the values resulting from FSI. Therefore, the decoupled simulation may underestimate the atheroprone sites of the artery and suggests that using FSI simulation for mechanical stimuli of ECs is inevitable.