Sturla Francesco, Redaelli Alberto, Puppini Giovanni, Onorati Francesco, Faggian Giuseppe, Votta Emiliano
Department of Electronics, Information and Bioengineering (DEIB), Politecnico di Milano, Via Golgi 39, 20133, Milan, Italy.
Division of Cardiovascular Surgery, Università degli Studi di Verona, Verona, Italy.
Cardiovasc Eng Technol. 2015 Jun;6(2):117-40. doi: 10.1007/s13239-014-0208-4. Epub 2014 Dec 17.
Mitral regurgitation is the most prevalent heart valve disease in the western population. When severe, it requires surgical treatment, repair being the preferred option. The edge-to-edge repair technique treats mitral regurgitation by suturing the leaflets together and creating a double-orifice valve. Due to its relative simplicity and versatility, it has become progressively more widespread. Recently, its percutaneous version has become feasible, and has raised interest thanks to the positive results of the Mitraclip(®) device. Edge-to-edge features and evolution have stimulated debate and multidisciplinary research by both clinicians and engineers. After providing an overview of representative studies in the field, here we propose a novel computational approach to the most recent percutaneous evolution of the edge-to-edge technique. Image-based structural finite element models of three mitral valves affected by posterior prolapse were derived from cine-cardiac magnetic resonance imaging. The models accounted for the patient-specific 3D geometry of the valve, including leaflet compound curvature pattern, patient-specific motion of annulus and papillary muscles, and hyperelastic and anisotropic mechanical properties of tissues. The biomechanics of the three valves throughout the entire cardiac cycle was simulated before and after Mitraclip(®) implantation, assessing the biomechanical impact of the procedure. For all three simulated MVs, Mitraclip(®) implantation significantly improved systolic leaflets coaptation, without inducing major alterations in systolic peak stresses. Diastolic orifice area was decreased, by up to 58.9%, and leaflets diastolic stresses became comparable, although lower, to systolic ones. Despite established knowledge on the edge-to-edge surgical repair, latest technological advances make its percutanoues implementation a challenging field of research. The modeling approach herein proposed may be expanded to analyze clinical scenarios that are currently critical for Mitraclip(®) implantation, helping the search for possible solutions.
二尖瓣反流是西方人群中最常见的心脏瓣膜疾病。病情严重时，需要进行手术治疗，首选修复手术。缘对缘修复技术通过将瓣叶缝合在一起并形成双孔瓣膜来治疗二尖瓣反流。由于其相对简单且用途广泛，该技术已越来越普及。最近，其经皮版本已变得可行，并且由于Mitraclip（®）装置取得的积极成果而引起了人们的关注。缘对缘技术的特点和发展引发了临床医生和工程师的讨论以及多学科研究。在概述该领域的代表性研究之后，我们在此提出一种新颖的计算方法，用于研究缘对缘技术最新的经皮发展。通过心脏电影磁共振成像得出了三个受后叶脱垂影响的二尖瓣基于图像的结构有限元模型。这些模型考虑了瓣膜特定于患者的三维几何形状，包括瓣叶复合曲率模式、特定于患者的瓣环和乳头肌运动，以及组织的超弹性和各向异性力学特性。在植入Mitraclip（®）之前和之后，模拟了这三个瓣膜在整个心动周期中的生物力学，评估了该手术的生物力学影响。对于所有三个模拟的二尖瓣，植入Mitraclip（®）均显著改善了收缩期瓣叶对合，且未引起收缩期峰值应力的重大改变。舒张期瓣口面积减小，降幅高达58.9%，瓣叶舒张期应力虽低于收缩期应力，但变得与之相当。尽管对缘对缘手术修复已有一定认识，但最新的技术进展使其经皮实施成为一个具有挑战性的研究领域。本文提出的建模方法可加以扩展，以分析目前对Mitraclip（®）植入至关重要的临床情况，有助于寻找可能的解决方案。
