NUMERICAL SIMULATION AND PIV MEASUREMENT OF TWO PROXIMAL ANASTOMOSIS MODELS

Hemodynamics is widely believed to influence the stenosis of coronary artery bypass graft (CABG). Although distal anastomosis has been extensively investigated, further studies on proximal anastomosis are still necessary, as the extent and initiation of stenosis process may be influenced by the flow at proximal anastomosis per se. Therefore, in this study, firstly, two models (namely 90° and 135° anastomotic models) were designed and constructed to mimic the proximal anastomosis of CABG for left and right coronary arteries, respectively. Flow characteristics of these models were studied by both numerical simulation and particle image velocimetry (PIV) measurement, so as to acquire physical insight of hemodynamics in proximal anastomosis and to validate the simulation result simultaneously. The simulation results showed disturbed flow (such as flow separation, stagnation point, etc.) as well as abnormal hemodynamic parameters (HPs) distributions (including the low and high time-averaged wall shear stress (WSS), oscillation shear index, and time-averaged wall shear stress gradient regions in both the models). In contrast to the 90° model studied, the 135° model is proposed to provide better patency rate, as it has reduced disturbed flow and abnormal HPs.

A fair agreement between numerical and experimental data has been observed in terms of flow characteristics, velocity profiles, and WSS distributions. The discrepancy could be due to the difference in detail geometry of the physical and computational models because of manufacturing limitations to have the exact shape of the computational model when making the Pyrex glass model.