The rapid expansion of TAVR to younger, low-risk patients raises concerns regarding device durability. Necessarily, extended stent lifetime will become more critical for new generation devices. In vitro methods commonly used for TAVR stent fatigue testing exclude the effects of the beating heart. We present a more realistic in silico stent fatigue analysis utilizing a beating heart model in which TAVR stents experience complex, nonuniform dynamic loading. Virtual TAVR deployments were simulated in the SIMULIA Living Heart Human Model of a beating heart using stent models of the self-expandable nitinol 26-mm CoreValve and Evolut R devices, and a 27-mm PolyV-2. Stent deformation was monitored over three cardiac cycles, and fatigue resistance was evaluated for the nitinol stents using finite element analysis via ABAQUS/Explicit. In all models, there were elements in which strains exceeded fatigue failure. The PolyV-2 stent had far fewer failing elements since its struts were optimized to reduce the strain in stent joints, achieving better fatigue resistance in the stent crown and waist elements. Different stent sections showed markedly different fatigue resistance due to the varying loading conditions. This study demonstrates the utility of advanced in silico analysis of devices deployed within a beating heart that mimics in vivo loading, offering a cost-effective alternative to human or animal trials and establishing a platform to assess the impact of device design on device durability. The limited fatigue life of TAVR stents indicated here highlights a clinical complication that may eventually develop as younger, lower-risk TAVR patients, age.

翻译：经导管主动脉瓣置换术（TAVR）向年轻、低风险患者群体的快速扩展引发了对器械耐久性的关注。新一代器械必须更注重延长支架寿命。目前用于TAVR支架疲劳测试的体外方法忽略了心脏搏动的影响。我们提出了一种更具现实意义的硅基支架疲劳分析方法，该方法利用包含复杂非均匀动态载荷的跳动心脏模型，模拟TAVR支架在其中的受力情况。通过自膨胀镍钛合金26mm CoreValve和Evolut R器械以及27mm PolyV-2支架模型，在SIMULIA Living Heart人体跳动心脏模型中完成了虚拟TAVR植入模拟。监测了三个心动周期内支架的变形情况，并利用ABAQUS/Explicit通过有限元分析评估了镍钛合金支架的抗疲劳性能。所有模型均存在应变超过疲劳失效阈值的单元。PolyV-2支架的失效单元数量显著减少，因为其支柱结构经过优化以降低支架连接处的应变，从而在支架冠部和腰部元件中实现了更优的抗疲劳性能。不同支架区段因载荷条件差异而表现出显著不同的抗疲劳能力。本研究证明了在模拟体内载荷的跳动心脏中进行器械植入的先进硅基分析方法的实用性，为人体或动物试验提供了经济高效的替代方案，并建立了评估器械设计对耐久性影响的平台。本研究所揭示的TAVR支架有限疲劳寿命，提示了随着年轻、低风险TAVR患者年龄增长可能逐渐出现的临床并发症。