Impact of Transcatheter Aortic Valve Size on Leaflet Stresses: Implications for Durability and Optimal Grey Zone Sizing.
Impact of Transcatheter Aortic Valve Size on Leaflet Stresses: Implications for Durability and Optimal Grey Zone Sizing.
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DOI：
10.4244/aij-d-19-00005
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发表时间：
2020-12
期刊：
影响因子：
--
通讯作者：
Tseng EE
中科院分区：
文献类型：
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作者：
Xuan Y;Dvir D;Wisneski AD;Wang Z;Ye J;Guccione JM;Ge L;Tseng EE
随着经导管主动脉瓣置换术（TAVR）的适应症不断向年轻和低风险患者扩展，耐久性成为一个越来越重要的问题。耐久性随瓣叶应力增加而降低，但经导管心脏瓣膜（THV）尺寸对应力的影响尚不清楚。患者瓣环尺寸可能在2种TAVR尺寸之间的“灰色区域”内。我们的目的是检查球囊扩张THV尺寸对瓣叶应力的影响。对SapienXT 23 mm、26 mm和29 mm尺寸（Edwards Lifesciences，Inc）进行微计算机断层扫描，以创建THV计算模型，然后使用有限元软件加载至全身压力。在平均动脉压下，THV瓣叶最大主应力分别为1.69 MPa（23 mm）、1.70 MPa（26 mm）和2.12 MPa（29 mm）。对于中等瓣环尺寸，尺寸过小的较大THV产生的瓣叶应力低于尺寸过大的较小THV。增加THV尺寸产生更大的瓣叶最大主应力，这可能表明THV尺寸与长期耐久性之间存在关系。对于瓣环“灰色区域”尺寸，尺寸过小的较大THV导致的瓣叶应力低于尺寸过大的较小THV。这些结果可能会影响最佳器械尺寸，因为THV耐久性仍然是一个重要的未回答的问题。生物瓣膜的耐久性是患者因素和瓣膜设计的复杂相互作用，但与瓣叶上的机械应力有关。对可扩张经导管心脏瓣膜（THV）进行微计算机断层扫描，以开发支架、涤纶和瓣叶的精确几何结构，用于计算建模。对全身压力进行动态有限元模拟，以确定THV尺寸对瓣叶应力的影响。增加THV尺寸导致瓣叶应力增加，这可能影响长期耐久性。然而，当瓣环尺寸落在两种THV尺寸之间的灰色区域内时，尺寸较小的较大THV导致瓣叶应力较低。
As indications for transcatheter aortic valve replacement (TAVR) continue to expand towards younger and lower-risk patients, durability becomes an increasingly important question. Durability decreases as leaflet stresses increase, but the impact of transcatheter heart valve (THV) size on stress is unknown. Patient annulus sizes can fall within “grey zones” between 2 TAVR sizes. Our aim was to examine the impact of balloon-expandable THV size on leaflet stresses. SapienXT 23mm, 26mm, and 29mm sizes (Edwards Lifesciences, Inc) underwent micro-computed tomography scanning to create THV computational models then loaded to systemic pressure using finite element software. THV leaflet maximum principal stresses were 1.69MPa (23mm), 1.70MPa (26mm), and 2.12MPa (29mm) at mean arterial pressure. For intermediate annulus sizes, undersizing the larger THV yielded lower leaflet stresses than oversizing the smaller THV. Increasing THV size yielded greater leaflet maximum principal stresses, which could suggest a relationship between THV size and long-term durability.. For annulus “grey zones” sizes, undersizing the larger THV resulted in lower leaflet stresses than oversizing the smaller THV. These results may influence optimal device sizing, as THV durability remains an important, unanswered question. Durability of bioprostheses is a complex interaction of patient factors and valve design, but is related to mechanical stresses on valve leaflets. Balloon-expandable transcatheter heart valves (THV) underwent micro-computed tomography to develop precise geometry of stent, Dacron, and leaflets for computational modeling. Dynamic finite element simulations to systemic pressure were performed to determine impact of THV size on leaflet stresses. Increasing THV size resulted in increased leaflet stresses, which may impact long-term durability. However, when annulus size fell within grey zones between two THV sizes, undersizing the larger THV resulted in lower leaflet stresses.