On the effects of leaflet microstructure and constitutive model on the closing behavior of the mitral valve.
On the effects of leaflet microstructure and constitutive model on the closing behavior of the mitral valve.
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DOI：
10.1007/s10237-015-0674-0
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发表时间：
2015-11
影响因子：
3.5
通讯作者：
Sacks MS
中科院分区：
文献类型：
--
作者：
Lee CH;Rabbah JP;Yoganathan AP;Gorman RC;Gorman JH 3rd;Sacks MS
最近的长期研究表明，严重二尖瓣关闭不全手术修复后3-5年的复发率并不令人满意，这表明过度的组织应力和由此引起的应变诱导的组织衰竭是控制手术修复治疗二尖瓣（MV）疾病成功的潜在病因。我们假设，在 MV 修复技术中恢复正常的 MV 组织应力最终将通过恢复 MV 正常稳态来提高修复耐久性。因此，我们通过结合实际的纤维微观结构和基于真实结构的本构模型，开发了微观和宏观解剖学上精确的 MV 有限元模型。我们研究了 MV 关闭行为，并使用大量体外数据来验证所提出的模型。进行比较和参数研究，以确定基本的模型保真度和信息，以实现理想的准确性。更重要的是，首次使用计算模拟研究了局部纤维系综行为与器官级 MV 闭合行为之间的相互关系。这些新颖的结果不仅表明了适当的参数范围，而且表明了在宏观组织水平上胶原/弹性蛋白纤维网络的微观结构调整（即拉直和重新定向）对于促进 MV 装置在器官水平的生理负荷下的正确接合和自然功能的重要性。所提出的计算模型将作为实现我们长期建模目标的逻辑第一步——促进最佳手术修复策略的模拟引导设计，以显着增强耐用性来治疗患病的 MV。
Recent long-term studies showed an unsatisfactory recurrence rate of severe mitral regurgitation 3–5 years after surgical repair, suggesting that excessive tissue stresses and the resulting strain-induced tissue failure are potential etiological factors controlling the success of surgical repair for treating mitral valve (MV) diseases. We hypothesized that restoring normal MV tissue stresses in MV repair techniques would ultimately lead to improved repair durability through the restoration of MV normal homeostatic state. Therefore, we developed a micro- and macro- anatomically accurate MV finite element model by incorporating actual fiber microstructural architecture and a realistic structure-based constitutive model. We investigated MV closing behaviors, with extensive in vitro data used for validating the proposed model. Comparative and parametric studies were conducted to identify essential model fidelity and information for achieving desirable accuracy. More importantly, for the first time, the interrelationship between the local fiber ensemble behavior and the organ-level MV closing behavior was investigated using a computational simulation. These novel results indicated not only the appropriate parameter ranges, but also the importance of the microstructural tuning (i.e., straightening and re-orientation) of the collagen/elastin fiber networks at the macroscopic tissue level for facilitating the proper coaptation and natural functioning of the MV apparatus under physiological loading at the organ level. The proposed computational model would serve as a logical first step toward our long-term modeling goal—facilitating simulation-guided design of optimal surgical repair strategies for treating diseased MVs with significantly enhanced durability.