Effect of Wall Elasticity on Endothelial Shear Stress Calculations in Coronary Arteries*

Endothelial shear stress (ESS) regulates the coronary artery wall’s crucial functions to resist injury, suppress inflammation, and prevent atherosclerosis. Progression of coronary atherosclerosis is closely linked to vessel anatomy and location, often occurring at the outer edges of vessel bifurcations. In these areas, disturbed laminar flow patterns result in low ESS. Previous studies based on invasive imaging modalities have shown association of low ESS with atherosclerosis progression, however these studies were limited to visualization of a single branch at a time with rigid walls. Similar to other arteries in the body, coronary arteries have elastic walls that may affect the calculation of flow-driven ESS. Therefore, in this study, we use patient-specific computational fluid dynamics models based on computed tomography angiography images of the full 3D coronary tree to determine the effect of wall elasticity on calculated ESS. Using fluid-structure interaction modeling for elastic wall models, we found no substantial difference in time-averaged ESS (TAESS) calculated using rigid versus elastic walls. In addition, we compare TAESS at internal and external curvature and examine the effect of arterial curvature on the calculation of ESS.