Hemodynamic Simulation of Intra-stent Blood Flow

Abstract

The stent has been a major breakthrough for the treatment of atherosclerotic vascular disease. The permanent vascular implant of a stent, however, changes the blood flow hemodynamics and may consequently affect the restenosis process. Computational Fluid Dynamics (CFD) has been widely used to analyze the hemodynamic behavior and wall shear stress (WSS) distribution in stented arteries. The objective of this study is to present a thorough comparison among various CFD models to investigate the effects of rheological properties and pulsatile flow on hemodynamic simulation of the intra-stent blood flow. Several CFD models were developed with various modeling setups – axisymmetric parallel ring vs. 3-D stented artery model, Newtonian vs. non-Newtonian flow, and steady-state vs. pulsatile flow. Simulated results show that the minimum WSS occurs at the recirculation zones located at the downstream or backside of each stent struts. The rheological effect on WWS is minor in the axisymmetric parallel ring model; however, it becomes slightly significant in the 3-D stented artery model, with Newtonian flow being a more conservative assumption. For given pulsatile waveforms, the steady-state and pulsatile flow resulted in fairly similar trends in the WSS distribution. Therefore, it is reasonable to simulate the intra-stent blood flow as a steady-state Newtonian flow, which could be beneficial in more complex simulations and drastically reduce the computational time. These findings will provide great insights for future stent design optimization to reduce restenosis.