Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
Biomed Eng Online. 2014 Mar 20;13(1):31. doi: 10.1186/1475-925X-13-31.
Computational simulation using numerical analysis methods can help to assess the complex biomechanical and functional characteristics of the mitral valve (MV) apparatus. It is important to correctly determine physical contact interaction between the MV apparatus components during computational MV evaluation. We hypothesize that leaflet-to-chordae contact interaction plays an important role in computational MV evaluation, specifically in quantitating the degree of leaflet coaptation directly related to the severity of mitral regurgitation (MR). In this study, we have performed dynamic finite element simulations of MV function with and without leaflet-to-chordae contact interaction, and determined the effect of leaflet-to-chordae contact interaction on the computational MV evaluation.
Computational virtual MV models were created using the MV geometric data in a patient with normal MV without MR and another with pathologic MV with MR obtained from 3D echocardiography. Computational MV simulation with full contact interaction was specified to incorporate entire physically available contact interactions between the leaflets and chordae tendineae. Computational MV simulation without leaflet-to-chordae contact interaction was specified by defining the anterior and posterior leaflets as the only contact inclusion.
Without leaflet-to-chordae contact interaction, the computational MV simulations demonstrated physically unrealistic contact interactions between the leaflets and chordae. With leaflet-to-chordae contact interaction, the anterior marginal chordae retained the proper contact with the posterior leaflet during the entire systole. The size of the non-contact region in the simulation with leaflet-to-chordae contact interaction was much larger than for the simulation with only leaflet-to-leaflet contact.
We have successfully demonstrated the effect of leaflet-to-chordae contact interaction on determining leaflet coaptation in computational dynamic MV evaluation. We found that physically realistic contact interactions between the leaflets and chordae should be considered to accurately quantitate leaflet coaptation for MV simulation. Computational evaluation of MV function that allows precise quantitation of leaflet coaptation has great potential to better quantitate the severity of MR.
使用数值分析方法进行计算模拟可以帮助评估二尖瓣（MV）装置的复杂生物力学和功能特性。在计算 MV 评估中，正确确定 MV 装置各组成部分之间的物理接触相互作用非常重要。我们假设瓣叶与腱索之间的接触相互作用在计算 MV 评估中起着重要作用，特别是在定量直接与二尖瓣反流（MR）严重程度相关的瓣叶对合程度方面。在这项研究中，我们对具有和不具有瓣叶与腱索接触相互作用的 MV 功能进行了动态有限元模拟，并确定了瓣叶与腱索接触相互作用对计算 MV 评估的影响。
使用从 3D 超声心动图获得的正常 MV 无 MR 的患者和病理性 MV 伴 MR 的患者的 MV 几何数据创建了计算虚拟 MV 模型。指定了具有完整接触相互作用的计算 MV 模拟，以纳入瓣叶和腱索之间的所有实际可利用的物理接触相互作用。指定了没有瓣叶与腱索接触相互作用的计算 MV 模拟，方法是将前、后瓣定义为唯一的接触包含物。
没有瓣叶与腱索接触相互作用，计算 MV 模拟显示瓣叶与腱索之间存在不切实际的物理接触相互作用。有瓣叶与腱索接触相互作用时，前瓣缘腱索在前整个收缩期内都与后瓣保持适当的接触。有瓣叶与腱索接触相互作用的模拟中的无接触区域的尺寸比只有瓣叶与瓣叶接触的模拟大得多。
我们成功地证明了瓣叶与腱索接触相互作用对确定计算动态 MV 评估中的瓣叶对合的影响。我们发现，应考虑瓣叶与腱索之间的实际接触相互作用，以准确定量 MV 模拟中的瓣叶对合。允许精确定量瓣叶对合的 MV 功能计算评估具有更好地定量 MR 严重程度的巨大潜力。
