摘要
Arteriovenous fistula(AVF)calcification is a common complication in hemodialysis patients that leads to AVF dysfunction and decreases the AVF survival,but the mechanisms of AVF calcification,especially the role of hemodynamic changes in AVF calcification have not been fully investigated.In this study,a computational fluid dynamics(CFD)model was carried out based on AVF,at the distal anastomosis of the cephalic vein and radial artery,generated from a patient-specific computed tomography(CT)angiography and Doppler ultrasound image.Hemodynamic factors were considered to explore the mechanisms responsible for the initiation and progression of AVF calcification.Five stages in one cardiac cycle were chosen to be studied for the velocity field,pressure,time-averaged wall shear stress(TAWSS),and oscillatory shear index(OSI).Blood pressure was higher in the arteriovenous anastomosis,and variations of great amplitude of pressure were examined during the cardiac cycle.Blood pressure,transient shear stress,TAWSS,and OSI were higher in the arteriovenous anastomosis and at the bottom of expanded outflow vein,and these sites were highly consistent with the calcified areas shown on CT angiography.On the contrary,no calcification was found in sites where streamline was stable,blood pressure did not change dramatically,as well as TAWSS and OSI were lower.It was shown that AVF calcification was correlated with hemodynamic changes,which may contribute to further understanding the mechanisms of AVF calcification and providing scientific evidence to inform the optimization of surgical strategies and the development of personalized interventional measures in clinical contexts.
动静脉内瘘(AVF)钙化是血液透析患者常见的并发症,会导致AVF功能障碍并降低AVF的寿命.然而,AVF钙化的机制,特别是血流动力学变化在AVF钙化中的作用尚未得到充分研究.本研究基于患者的计算机断层扫描(CT)血管造影和多普勒超声图像生成的参数建立远端桡动脉-头静脉AVF的计算流体动力学模型,探讨血流动力学机制在AVF钙化发生与发展中的作用.选择心动周期中的五个阶段来分析速度场、压强、时间平均壁面剪切应力(TAWSS)和振荡剪切指数(OSI)的特征及其与钙化的关系.动静脉吻合处的压强较高,在心动周期中观察到大幅度的压强变化.动静脉吻合处和扩张的静脉流出道底部的压强、瞬时切应力、TAWSS和OSI值较高,这些位置与CT血管造影显示的钙化区域高度一致.相反,在血流稳定、压强变化不大以及TAWSS和OSI值较低的区域未发现钙化.结果表明,AVF钙化与血流动力学变化相关,这可能有助于进一步理解AVF钙化的机制,并为临床优化手术策略和制定个性化干预措施提供科学依据.
基金
supported by the Scientific Program of Tianjin Municipal Education Commission(Natural Science,Grant No.2022KJ254)
Science Foundation of the Second Hospital of Tianjin Medical University(Grant No.2021ydey05)
Tianjin Municipal Health Commission Integrated Traditional Chinese and Western Medicine Project(Grant No.2021173).
