Prosthetic heart valve interventions such as TAVR have surged over the past decade, but the associated complication of long-term, life-threatening thrombotic events continues to undermine patient outcomes. Thus, improving thrombogenic risk analysis of TAVR devices is crucial. In vitro studies for thrombogenicity are typically difficult to perform. However, revised ISO testing standards include computational testing for thrombogenic risk assessment of cardiovascular implants. We present a fluid-structure interaction (FSI) approach for assessing thrombogenic risk of prosthetic heart valves. An FSI framework was implemented via the incompressible computational fluid dynamics multi-physics solver of the Ansys LS-DYNA software. The numerical modeling approach for flow analysis was validated by comparing the derived flow rate of the 29-mm CoreValve device from benchtop testing and orifice areas of commercial TAVR valves in the literature to in silico results. Thrombogenic risk was analyzed by computing stress accumulation (SA) on virtual platelets seeded in the flow fields via Ansys EnSight. The integrated FSI-thrombogenicity methodology was subsequently employed to examine hemodynamics and thrombogenic risk of TAVR devices with two approaches: 1) engineering optimization and 2) clinical assessment. Our methodology can be used to improve the thromboresistance of prosthetic valves from the initial design stage to the clinic. It allows for unparalleled optimization of devices, uncovering key TAVR leaflet design parameters that can be used to mitigate thrombogenic risk, in addition to patient-specific modeling to evaluate device performance. This work demonstrates the utility of advanced in silico analysis of TAVR devices that can be utilized for thrombogenic risk assessment of other blood recirculating devices.

翻译：过去十年间，经导管主动脉瓣置换术（TAVR）等人工心脏瓣膜介入治疗大幅增加，但与之相关的长期致命性血栓事件并发症持续影响患者预后。因此，改进TAVR装置的血栓形成风险分析至关重要。针对血栓形成特性的体外研究通常难以实施。然而，修订后的ISO测试标准已包含对心血管植入物进行血栓形成风险评估的计算测试。本文提出一种用于评估人工心脏瓣膜血栓形成风险的流固耦合（FSI）方法。该FSI框架通过Ansys LS-DYNA软件中的不可压缩计算流体动力学多物理场求解器实现。通过将29-mm CoreValve装置在台架试验中获得的流量数据、文献中商用TAVR瓣膜的开口面积与计算机模拟结果进行对比，验证了血流分析数值建模方法的有效性。血栓形成风险通过Ansys EnSight计算流场中虚拟血小板上的应力累积（SA）进行分析。该集成FSI-血栓形成特性研究方法随后被用于通过两种途径考察TAVR装置的血液动力学特性与血栓形成风险：1）工程优化；2）临床评估。本方法可用于从初始设计阶段到临床阶段持续改善人工瓣膜的抗血栓性能。该方法不仅能实现无与伦比的装置优化，揭示可用于降低血栓形成风险的关键TAVR瓣叶设计参数，还能通过患者特异性建模评估装置性能。本研究表明，这种先进的TAVR装置计算机模拟分析方法可推广应用于其他血液再循环装置的血栓形成风险评估。