Numerical Simulation of Hemodynamics Blood Flow through Single and Double Stenotic Coronary Arteries

In this study, we present a computational model utilizing a Newtonian fluid assumption to investigate blood flow characteristics in arteries with single and double stenosis. We have used COMSOL Multiphysics software with a suitable validation to evaluate the hemodynamic parameters. The geometry of the arterial segment with single and double stenosis has been considered to analyze their effects on flow patterns, wall shear stress distribution, velocity, and pressure gradients. Results reveal the significant alterations in flow velocity profiles and pressure gradients downstream of the stenotic regions, leading to changes in wall shear stress distribution along the arterial wall for the higher severity. Greater stenosis severity results in higher wall shear stress at the constricted region; and in the case of double stenosis, the wall shear stress is slightly lower for the second stenosis than that of the first. For single stenosis with severity levels of 45%, 60%, and 75%, the results of inlet pressures are 773.49 Pa, 1001.1 Pa, and 2041.9 Pa, respectively. In the double stenosis configuration, inlet pressures have been increased to 874.57 Pa, 1304.5 Pa, and 3055.6 Pa for the same severity levels. The study has shown that both increasing stenosis severity and the presence of multiple stenoses significantly elevate inlet pressure. Further, for single stenosis, results indicate that as stenosis severity increases, the separation point moves upstream, the reattachment point shifts downstream, and the recirculation length expands significantly (0.99 mm for 45% stenosis, 3.20 mm for 60%, and 9.30 mm for 75%). In the double stenosis case, a second recirculation zone is observed, with larger and more prolonged disturbed flow regions compared to single stenosis. The first and second stenoses exhibit distinct separation and reattachment points, with recirculation lengths increasing as severity progresses (e.g., 4.76 mm and 10.44 mm for 75% severity). These findings highlight the hemodynamic significance of stenosis severity and location, as larger recirculation zones and flow disturbances may contribute to vascular complications, endothelial damage, and plaque progression.