Razavi Seyed Esmail, Talebi Amin
Faculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran.
Bioimpacts. 2023;13(4):323-332. doi: 10.34172/bi.2023.24097. Epub 2023 Jan 7.
Computational modeling is one of the best non-invasive approaches to predicting the functional behavior of the mitral valve (MV) in health and disease. Mitral valve prolapse (MVP) due to partial or complete chordae tendineae rapture is the most common valvular disease and results in mitral regurgitation (MR).
In this study, Image-based fluid-structure interaction (FSI) models of the human MV are developed in the normal physiological and posterior leaflet prolapse conditions. Detailed geometry of the healthy human MV is derived from Computed Tomography imaging data. To provide prolapse condition, some chords attached to the posterior leaflet are removed from the healthy valve. Both normal and prolapsed valves are embedded separately in a straight tubular blood volume and simulated under physiological systolic pressure loads. The Arbitrary Lagrangian-Eulerian finite element method is used to accommodate the deforming intersection boundaries of the blood and MV.
The stress values in the mitral components, and also flow patterns including the regurgitant flow rates are obtained and compared in both conditions through the simulation. These simulations have the potential to improve the treatment of patients with MVP, and also help surgeons to have more realistic insight into the dynamics of the MV in health and prolapse.
In the prolapse model, computational results show incomplete leaflet coaptation, higher MR severity, and also a significant increment of posterior leaflet stress compared to the normal valve. Moreover, it is found more deviation of the regurgitant jet towards the left atrium wall due to the posterior leaflet prolapse.
计算建模是预测健康和患病状态下二尖瓣(MV)功能行为的最佳非侵入性方法之一。由于部分或完全腱索断裂导致的二尖瓣脱垂(MVP)是最常见的瓣膜疾病,会导致二尖瓣反流(MR)。
在本研究中,基于图像的人体二尖瓣流固耦合(FSI)模型在正常生理和后叶脱垂条件下被建立。健康人体二尖瓣的详细几何结构源自计算机断层扫描成像数据。为提供脱垂条件,从健康瓣膜上移除一些附着在后叶上的腱索。正常瓣膜和脱垂瓣膜分别嵌入直的管状血容量中,并在生理收缩压负荷下进行模拟。采用任意拉格朗日 - 欧拉有限元方法来处理血液和二尖瓣变形的相交边界。
通过模拟获得并比较了两种情况下二尖瓣各组件的应力值以及包括反流流速在内的血流模式。这些模拟有潜力改善MVP患者的治疗,也有助于外科医生更真实地了解健康和脱垂状态下二尖瓣的动力学。
在脱垂模型中,计算结果显示瓣叶对合不完全、MR严重程度更高,并且与正常瓣膜相比后叶应力显著增加。此外,发现由于后叶脱垂,反流束向左心房壁的偏移更大。