主动脉内经皮左心室辅助泵出口处流场非定常模拟分析及其影响

A simulation analysis on the unsteady flow field at outlet of intra-aortic percutaneous left ventricular assist pump and its influence

目的:分析主动脉内经皮左心室辅助泵出口处的径向血流及其对主动脉内皮细胞造成损伤的可能性。方法:运用计算流体力学(CFD)对一款经皮左心室辅助泵在主动脉直径分别为20、30、40 mm 3种情况下进行非定常数值仿真,分析血泵出口处的流场分布。通过研究其速度、压力和剪切应力分布情况来分析血泵径向血流对主动脉血管内皮细胞的影响。结果:数据结果显示,血泵出口处的径向血流对3个模型额外增加的正应力分别为24、17、8 mmHg,近壁面剪切应力大于25 Pa的比例分别为19.3%、13.6%、3.0%。结论:实验表明,经皮左心室辅助泵的植入会增大主动脉压和近壁面剪切应力,而且主动脉直径越小,其效果越明显,因此对于主动脉直径偏小、患有高血压或动脉病变的患者应谨慎使用。

Objective To analyze the radial flow at the outlet of intra-aorta percutaneous left ventricular assist pump and itspossibility of damage to aortic endothelial cells.Methods Based on computational fluid dynamics(CFD),the numerical imitation of unsteady flow was carried in a percutaneous left ventricular assist pump with different aortic diameters of 20,30 mm,and 40 mm,and the flow field distribution at the outlet of the pump was analyzed.The effects of radial blood flow on aortic vascular endothelial cells were analyzed by studying the distribution of velocity,pressure and shear stress.Results The results showed that the radial blood flow at the outlet of the pump increased the normal stresses of the three models by respectively 24,17 mmHg,and 8 mmHg,and the proportions of near-wall shear stress greater than 25 Pa are 19.3%,13.6%,and 3%,respectively.Conclusions Experiments showed that the percutaneous left ventricular assist pump can increase the aortic pressure and near-wall shear stress,and the smaller the aortic diameter,the more obvious the effect.Therefore,patients with small diameter of aorta,hypertension or arterial lesions should be cautious to use.