基于自体动静脉内瘘特定患者的血流动力学分析

Hemodynamic Analysis of Arteriovenous Fistula in Specific Patients

目的:建立自体动静脉内瘘(Arteriovenous fistulas, AVF)特定患者的理想模型,运用计算流体动力学(Computational fluid dynamics, CFD)方法分析血流行为,为医生的临床研究和诊断提供参考。方法:采集临床数据,作为建模和仿真的基础。采用牛顿血液模型,设置速度–压力耦合边界条件进行仿真计算,结果选取速度、流线、壁面剪切应力(Wall Shear Stress, WSS)图以及特定截面的平均速度与面积平均壁面剪切应力数值结果参与血流动力学的评估。结果:对于流速与流线,两模型的平均速度均由桡动脉上游逐渐向瘘管下游递减,高速血流都分布于模型瘘管段的外侧,而端侧模型中靠近吻合口的上游,则集中于模型内侧。WSS的分布规律与流速和流线的分布大体相同,端侧模型在所有结果中还观测到了不对称的分布。结论:本研究证实了CFD方法在临床诊断上有一定参考价值,端侧内瘘在实际情况下血流状况比端端内瘘更为复杂。

Objective: Establish ideal models of Arteriovenous fistulas (AVF) in specific patients, and use com-putational fluid dynamics (CFD) to analyze blood behavior to provide reference for doctors’ clinical research and diagnosis. Methods: Collect clinical data as a basis for modeling and simulation. New-tonian blood models were used, and the velocity-pressure coupling boundary conditions are set for simulation calculation. In the results, the plot of velocity, streamline, Wall Shear Stress (WSS), as well as the average velocity and area average wall shear stress numerical results of specific sections were selected to participate in the hemodynamic evaluation. Results: For the velocity and stream-line, the axial comparison shows that the average velocity of the two models gradually decreases from the PA segment to the VD segment. The cross-sectional comparison showed that the high-speed blood flow was distributed on the outside of the VD segment of the model, while the PA segment near the anastomosis in the end-to-side model was concentrated on the inside of the model. The distribution of WSS is roughly the same as the distribution of velocity and streamline, and the end-to-side model also observed asymmetric distribution in all results. Conclusions: This study con-firms that the CFD method has some reference value in clinical diagnosis, and end-to-side fistula is more complicated in practice than end-to-end fistula.