Avanzini Andrea, Battini Davide
Department of Mechanical and Industrial Engineering, University of Brescia, Brescia, Italy
Department of Mechanical and Industrial Engineering, University of Brescia, Brescia, Italy.
Proc Inst Mech Eng H. 2014 Oct;228(10):985-95. doi: 10.1177/0954411914552309. Epub 2014 Sep 23.
Our aim was to understand the structural and functional behaviour of a pericardial heart valve with biological leaflets attached externally to a stent. To our knowledge, there is little if any literature concerning these kinds of bioprosthetic heart valves, while there is more concerning bioprosthetic heart valves with leaflets mounted internally. We studied the problem using a finite element approach considering leaflets and stent interaction, the influence of leaflet anisotropy and stent stiffness, by comparing quasi-static and dynamic loadings. Although we considered the problem to be symmetric and fluid-structure interaction was not implemented, we believe that our results could be a solid basis for valve optimization. We found regions of high stress concentration at the commissure near the stent tip and at the base of the leaflet cusp. The structural behaviour in the first region was complex, while the stress in the second region acted radially because of high bending. Although leaflet tissue anisotropy and stent stiffness exerted a significant influence on the structural and functional behaviours, they had a contrasting effect on leaflet stress state, coaptation and valve opening. Therefore, a good optimization should take into account both structural and functional requirements when tuning tissue properties and stent stiffness.
我们的目的是了解一种心包心脏瓣膜的结构和功能行为，该瓣膜的生物瓣叶附着在外部的支架上。据我们所知，关于这类生物人工心脏瓣膜的文献极少，而关于瓣叶安装在内部的生物人工心脏瓣膜的文献则较多。我们采用有限元方法研究了这个问题，考虑了瓣叶与支架的相互作用、瓣叶各向异性和支架刚度的影响，并比较了准静态和动态载荷。尽管我们认为该问题具有对称性且未考虑流固相互作用，但我们相信我们的结果可为瓣膜优化提供坚实基础。我们发现，在靠近支架尖端的连合处以及瓣叶尖的基部存在高应力集中区域。第一个区域的结构行为较为复杂，而由于高度弯曲，第二个区域的应力呈径向作用。尽管瓣叶组织各向异性和支架刚度对结构和功能行为有显著影响，但它们对瓣叶应力状态、贴合度和瓣膜开放有相反的作用。因此，在调整组织特性和支架刚度时，良好的优化应同时考虑结构和功能要求。
