Computational Fluid Dynamics Analysis of Coronary Stenosis: Hemodynamic and Geometric Determinants of Shear Stress Behavior on the Endothelial Wall

Even young, asymptomatic individuals with non-obstructive coronary disease can expe-rience acute myocardial infarction due to plaque rupture. Computational fluid dynamics (CFD) enables the simulation of coronary hemodynamics and wall shear stress (WSS), a key biomechanical factor in plaque vulnerability. However, the influence of varying coro-nary geometries and flow conditions on WSS behavior remains unclear. This study ana-lyzed how geometric factors (arterial diameter, tapering, and stenosis location) and he-modynamic or rheological parameters (inlet pressure, hematocrit) affect WSS distribution through CFD simulations. Idealized models of the left anterior descending, left circumflex, and right coronary arteries with 50% stenosis, along with a real right coronary artery mesh for validation, were evaluated under physiological conditions. Changes in hemato-crit modified blood viscosity and density. Ansys CFD simulations showed that both geo-metric and hemodynamic factors significantly impact WSS. Higher hematocrit and inlet pressure increased WSS; larger diameters led to nonlinear amplification; and distal or ta-pered lesions altered shear stress distribution. WSS values often exceeded 30 Pa, aligning with previous findings. Even minor modifications in geometry or blood properties caused notable changes in WSS, indicating that percent stenosis and fractional flow reserve (FFR) alone may be inadequate to fully assess the risk of plaque rupture.