Collaborative Research: Advancing the Diagnosis and Quantification of Mitral Valve Regurgitation with Mathematical Modeling

二尖瓣返流（MR）是一种瓣膜疾病，其中二尖瓣不能正确关闭，从而允许血液从左心室回流到心脏的左心房。二尖瓣返流是西方世界最普遍的瓣膜问题之一。多普勒超声心动图最近已成为非侵入性检测和评估二尖瓣返流严重程度的首选方法。然而，由于各种彩色多普勒的限制，MR的准确定量仍然是现代超声心动图的主要挑战之一。这是特别的情况下，偏心，贴壁射流，被称为柯恩达效应。这种形式的二尖瓣返流目前很难量化，可能导致经验不足的心血管观察者严重低估二尖瓣返流量。研究人员利用数学建模、分叉分析和数值模拟，结合MR的体外实验建模和临床经验，正在开发一种最先进的工具，用于准确无创评估二尖瓣返流。数学方法利用流体-结构相互作用的最新进展，模拟不可压缩粘性流体的流动，再加上模拟阻尼阀的弹性阻尼孔的运动。一个分叉图提供有关不同类型的MR的信息正在开发中。体外模型是基于脉动流回路纳入模拟成像室，其中包含一个模拟MR患者遇到的流动条件的返流孔。这是一个令人兴奋的，新的研究，解决了一个重要的问题，在开发非侵入性诊断工具的瓣膜返流的量化。跨学科的研究团队正在开发复杂的新型数学，高性能计算和体外实验工具，当它们一起使用时，可以提供有关二尖瓣返流严重程度的新信息，这些信息无法通过单独使用每种方法获得。基于这种合作奋进，将获得关于患者瓣膜中血流状况的详细信息，这是使用经典的2D甚至3D超声心动图无法获得的。该信息将用于量化二尖瓣返流的严重程度，这是决定手术干预的基本数据。互补的数学工具，结合超声心动图图像和临床经验，支持现代3D超声心动图发展的下一步，用于病理复杂心内血流的无创诊断。更广泛的影响将通过跨学科培训和跨学科课程准备的学生教育来实现。其中两名调查员是妇女，将继续积极征聘妇女和少数族裔。该项目有助于建立学术界（休斯顿大学）和健康/医疗行业（卫理公会医院）之间的强有力的伙伴关系。

Mitral regurgitation (MR) is a valvular disease in which the mitral valve does not close properly, thereby allowing blood to flow backward from the left ventricle to the left atrium of the heart. MR is among the most prevalent valve problems in the Western world. Doppler echocardiography has recently emerged as the method of choice for the non-invasive detection and evaluation of MR severity. However, due to the various color Doppler limitations, the accurate quantification of MR remains one of the major challenges in modern echocardiography. This is particularly the case with eccentric, wall-hugging regurgitant jets, known as the Coanda effect. This form of MR is currently very difficult to quantify and may lead to gross under-estimation of regurgitant volume by inexperienced cardiovascular observers. Using mathematical modeling, bifurcation analysis, and numerical simulations, combined with the in vitro experimental modeling of MR, and clinical experience, the investigators are developing a state-of-the-art tool for accurate non-invasive assessment of mitral regurgitation. The mathematical approach utilizes the most recent advances in fluid-structure interaction, modeling the flow of an incompressible, viscous fluid, coupled with the motion of an elastic regurgitant orifice simulating the regurgitant valve. A bifurcation diagram providing the information about different types of MR is being developed. The in vitro model is based on a pulsatile flow loop incorporating a mock imaging chamber, which contains a regurgitant orifice simulating the flow conditions encountered in patients with MR.This is an exciting, new study, addressing a significant problem in the development of non-invasive diagnostic tools for the quantification of valvular regurgitation. The interdisciplinary team of investigators is developing sophisticated novel mathematics, high performance computing, and in vitro experimental tools, which, when used together, provide novel information about the severity of mitral valve regurgitation, that could not be obtained by using each individual approach separately. Based on this collaborative endeavor, detailed information about the blood flow conditions in patient regurgitant valves will be obtained, that could not be obtained by using classical 2D or even 3D echocardiography. This information will be used to quantify the severity of MR, which is the fundamental data on which surgical interventions are decided. The complementary mathematical tools, combined with the echocardiographic images, and clinical experience, support the next step in the evolution of modern 3D echocardiography for non-invasive diagnosis of pathological complex intra-cardiac flows. The broader impacts will be achieved through student education via interdisciplinary training and interdisciplinary course preparation. Two of the investigators are women, and active recruitment of women and minorities will continue. This project contributes toward building a strong partnership between academia (University of Houston) and health/medical industry (The Methodist Hospital).