窦部对称狭窄对颈动脉内流场影响的数值研究

以颈动脉分岔血管为例，采用数值方法研究了窦部环缩狭窄之后的流场分布情况，并和正 常血管情况下的流场分布进行了比较. 结果表明，采用环缩方式给颈动脉分岔血管施加对称 的狭窄改变了颈动脉窦内流场，特别是壁面剪应力的分布规律. 低剪应力区出现在狭窄段之 后的窦内，并且沿整个周向均匀分布. 根据低剪应力和动脉粥样硬化的关系，指出： 若人为地给颈动脉窦内施加对称狭窄，则脂质沉积将在狭窄下游的窦内沿周向轴对称 发展. 为了更真实地反映颈动脉窦内的狭窄，建议根据动脉血管中的实际狭窄情况，采用非 对称的狭窄分布模式.

Numerical study on the influence of a symmetrical stenosis at the carotid sinus on the flow in the carotid bifurcation

The operation of ring constraining, which produce a symmetrical stenosis to artery, was a usually used method to establish an animal model or in vitro arterial atherosclerosis model because the straitness degree can be controlled easily and quantitatively. However, it is unknown how the flow field will be changed, and whether the flow field is similar to that under physiological stenosis when a ring constraining employed to bifurcation or bended artery. To understand tile flow in bifurcation artery under a ring constraining, carotid bifurcation with a symmetrical stenosis to the carotid sinus was instanced. The velocity profile, the secondary flow and the distribution of wall shear stress in the stenosed carotid bifurcation were numerically studied. The results were compared with those in the healthy carotid bifurcation. It was shown that the flow field in the carotid sinus, especially, the distribution of wall shear stress, was changed. Low wall shear stress was axissymmetrically distributed on the wall of the backward site of stenosis. Based on the influence of low wall shear stress on atherosis, it was prompted that atherosis might take place axis-symmetrically in the backward site of stenosis. It is obviously different to the physiological process of atherosis. Therefore, it is indicated that the symmetrical stenosis is not suitable for simulating the carotid sinus stenosis. To simulate the physiological stenosis in the carotid sinus, an asymmetrical stenosis should be employed.