Nappi Francesco, Spadaccio Cristiano, Mihos Christos G, Fraldi Massimiliano
Department of Cardiac Surgery, Centre Cardiologique du Nord de Saint-Denis, Paris, France.
Department of Cardiothoracic Surgery, Golden Jubilee National Hospital, Glasgow, UK.
J Thorac Dis. 2017 Jun;9(Suppl 7):S624-S628. doi: 10.21037/jtd.2017.05.63.
Ischemic mitral regurgitation (IMR) is a form of mitral insufficiency that is characterized by papillary muscle (PM) displacement, leaflet tethering, reduced closing forces, and different degree of annular dilatation. Treatment of this condition includes mitral valve replacement or mitral valve repair with restrictive annuloplasty. Recent evidences in mitral valve repair showed that addressing only the annulus and neglecting the subvalvular apparatus provides a suboptimal operation with poor long-term results. However, the complexity of the geometrical aberrances occurring in IMR demands for more accurate analysis also involving the biomechanics underlying the failing mitral valve and subvalvular apparatus. Finite element analysis (FEA) is a powerful tool in this context and we developed a biomechanical model of mitral valve and subvalvular unit using 3D geometry of the leaflets, annulus, chordae and PM. After the application of structural properties of materials to these elements and simulation of systemic pressure loading, FEA could be used to directly determine biomechanical changes and geometry variations. We believe this approach can provide valuable information to better address the surgical treatment of IMR and answer some of the questions still pending in IMR management.
缺血性二尖瓣反流(IMR)是二尖瓣关闭不全的一种形式,其特征为乳头肌(PM)移位、瓣叶牵拉、关闭力降低以及不同程度的瓣环扩张。这种病症的治疗方法包括二尖瓣置换或采用限制性瓣环成形术进行二尖瓣修复。二尖瓣修复的最新证据表明,仅处理瓣环而忽略瓣下结构会导致手术效果欠佳,长期结果不理想。然而,IMR中出现的几何畸变的复杂性需要更精确的分析,这也涉及到功能失调的二尖瓣和瓣下结构的生物力学原理。在这种情况下,有限元分析(FEA)是一种强大的工具,我们利用瓣叶、瓣环、腱索和乳头肌的三维几何结构建立了二尖瓣和瓣下单元的生物力学模型。在将材料的结构特性应用于这些元件并模拟系统压力负荷后,FEA可用于直接确定生物力学变化和几何形状变化。我们相信这种方法可以提供有价值的信息,以更好地应对IMR的外科治疗,并回答IMR管理中仍悬而未决的一些问题。