Numerical simulation for hemodynamics of the myocardial bridging parietal coronary artery / 医用生物力学

ABSTRACT

Objective To numerically simulate the blood flow in myocardial bridging parietal coronary artery and investigate the hemodynamics mechanism of the fact that atherosclerosis is more likely to occur in proximal segment of the parietal coronary artery. Methods The model, a straight tube with local stenosis which moved along with heart beating being used in order to simulate the morphology of myocardial bridging parietal coronary artery, was established. The wall of the tube was assumed as a thin wall linear elastomer, and the blood flow was assumed as a series of one dimensional flow equations following incompressible Newtonian fluid. The Lax-Wendroff method was also adopted to solve the governing equations numerically. Results There were significant differences in blood flow, wall shear stress and wall shear stress gradient between parietal coronary artery and normal coronary artery. For parietal coronary artery, the changes of wall shear stress and wall shear stress gradient were more dramatic in proximal segment than those in distal segment. As for two myocardial bridgings in one coronary artery, the trend of the wall shear stress and wall shear stress gradient was essentially the same, but the wall shear stress and wall shear stress gradient in myocardial bridging far from the ventricle were larger than those in myocardial bridging near the ventricle, with a more dramatic change along the time during one cardiac cycle. Conclusions Simulation results indicate that hemodynamics of parietal coronary artery is different from that of normal coronary artery. Changes of wall shear stress and wall shear stress gradient are more dramatic in proximal segment than those in distal segment, thus having an important impact on the local endothelial cells. It might be the hemodynamic mechanism of the fact that atherosclerosis is more likely to be developed in proximal segment of parietal coronary artery.