基于流固耦合方法的冠状动脉偏心与同心狭窄流场特性及血流动力学对比研究

Comparison of flow field characteristics and hemodynamics between eccentric and concentric coronary stenoses based on fluid-structure interaction

摘要

目的：利用流固耦合技术，定量解析不同位置及程度的偏心与同心狭窄对血流动力学及血管壁应力的差异化影响。方法：基于患者特异性冠状动脉CT血管成像（CCTA）影像重建多组不同构型的冠状动脉模型，应用患者特异性脉动压力及三元件Windkessel出口模型进行双向流固耦合计算。综合分析血流流态、时间平均壁面剪切应力（TAWSS）、振荡剪切指数（OSI）、相对停留时间（RRT）及管壁冯·米塞斯应力（VMS）。结果：研究表明，偏心几何特征显著改变了局部流场结构。在本研究中，相比于同心狭窄，偏心模型因射流偏转效应表现出独特的力学不稳定性：近段50%偏心狭窄模型高OSI与高RRT共定位区域占比最高（0.17%）；近段65%偏心模型其狭窄上下游低TAWSS区域占比最高（1.46%），且其管壁VMS峰值最高（14.71 kPa）并表现出应力集中。结论：冠状动脉狭窄的偏心几何特征是重塑局部流场与应力分布的关键因素。近段重度偏心狭窄同时面临狭窄上下游病变进展与喉部破裂的双重力学风险。因此，结合几何构型的生物力学分析可为冠脉风险分层提供重要的补充信息。

Abstract

Objective To quantitatively analyze the differential effects of eccentric versus concentric stenoses at different anatomical sites with various severities on hemodynamics and vescular wall stresses using fluid-structure interaction (FSI). Methods Based on patient-specific coronary computed tomography angiography (CCTA) data, a series of coronary artery models featuring distinct geometric configurations were reconstructed. Two-way FSI coupling calculations were executed using patient-specific pulsatile pressure profiles as inlet conditions and a three-element Windkessel (RCR) model as outlet boundary conditions. A comprehensive multi-parametric analysis was conducted to evaluate flow patterns, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and structural von Mises stress (VMS) within the vessel wall. Results Eccentric geometric features significantly reshaped the local flow field structure. Compared with concentric stenosis, eccentric models exhibited unique biomechanical instability due to the jet deflection effect. Specifically, the 50% proximal eccentric stenosis model showed the highest area fraction (0.17%) of regions with co-localized high OSI and high RRT. The 65% proximal eccentric model exhibited the highest area fraction (1.46%) of low TAWSS regions upstream and downstream of the stenosis, and its wall VMS peak was the highest (14.71 kPa), demonstrating distinct stress concentration. Conclusion The eccentric geometric feature of coronary stenosis is a key factor in reshaping the local flow field and stress distribution. Proximal severe eccentric stenosis encounters dual biomechanical risks: downstream lesion progression and plaque rupture at the stenotic throat. Therefore, biomechanical analysis incorporating geometric configurations can provide essential supplementary information for coronary risk stratification.

关键词

冠状动脉狭窄 / 流固耦合 / 偏心狭窄 / 血流动力学

Key words

coronary artery stenosis / fluid-structure interaction / eccentric stenosis / hemodynamics

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基金资助

国家自然科学基金(82001912)

徐州市科技计划项目-重点研发计划（社会发展）(KC20191)