Numerical simulation of the haemodynamics in end‐to‐side anastomoses

Abstract

AbstractIn this paper, the commercial CFD package Ansys workbench 11 was used to analyse the three‐dimensional haemodynamics of a typical stenotic Coronary Artery Bypass Grafting (CABG). Two end‐to‐side CABG configurations with anastomosis angle of 20∘ and 40∘ and graft–artery diameter ratios of 1/0.6, 1/1 and 1/1.6 were examined. The flow measurements from in vitro Doppler guide wire technique acquired in left interior mammary artery (LIMA) and grafted to the left anterior descending artery (LAD) were used to impose the physiologically flow conditions at proximal and distal CABG inlet and outlet, respectively. The blood flow was considered to be incompressible, pulsatile, Newtonian, and laminar rheology. The main objective was to determine the effect of anastomosis angle and graft–artery diameter ratio on the flow patterns and the long‐term functionality of the graft. In analysing the results, the distributions of temporal and spatial wall shear stress (WSS) gradient and oscillating shear index (OSI) in the critical regions of CABG such as heel, toe and the centre of the junction were presented and the vortex motions and the occurrence of recirculation zones were examined. The findings showed asymmetrically disturbed flows in the localized regions of the proximal and distal host artery for all models considered and the movement of the recirculation zones from heel to toe was found to depend on the time at the cardiac cycle. These regions are known as susceptible sites to thrombosis and re‐stenosis due to their association with low values of WSS. Copyright © 2010 John Wiley & Sons, Ltd.