Division of Cardiology, Department of Internal Medicine and the Baylor Scott and White Heart and Vascular Hospital, Baylor University Medical Center, Dallas, TX (M.P., P.A.G.).
Imperial College, London, United Kingdom (M.P.).
Circulation. 2019 Aug 27;140(9):779-789. doi: 10.1161/CIRCULATIONAHA.119.039612. Epub 2019 May 1.
Two distinct pathways can lead to functional mitral regurgitation (MR) in patients with chronic heart failure and a reduced ejection fraction. When remodeling and enlargement of the left ventricle (LV) cause annular dilatation and tethering of the mitral valve leaflets, there is a linear relationship between LV end-diastolic volume and the effective regurgitant orifice area of the mitral valve. These patients, designated as having proportionate MR, respond favorably to treatments that lead to reversal of LV remodeling and a decrease in LV volumes (eg, neurohormonal antagonists and LV assist devices), but they may not benefit from interventions that are directed only at the mitral valve leaflets (eg, transcatheter mitral valve repair). In contrast, when ventricular dyssynchrony causes functional MR attributable to unequal contraction of the papillary muscles, the magnitude of regurgitation is greater than that predicted by LV volumes. These patients, designated as having severe but disproportionate MR, respond favorably to treatments that are directed to the mitral valve leaflets or their supporting structures (eg, cardiac resynchronization or transcatheter mitral valve repair), but they may derive little benefit from interventions that act only to reduce LV cavity size (eg, pharmacological treatments). This novel conceptual framework reflects the important interplay between LV geometry and mitral valve function in determining the clinical presentation of patients, and it allows characterization of the determinants of functional MR to guide the most appropriate therapy in the clinical setting.
两种不同的途径可导致射血分数降低的慢性心力衰竭患者发生功能性二尖瓣反流（MR）。当左心室（LV）重构和扩大导致瓣环扩张和二尖瓣瓣叶牵拉时，LV 舒张末期容积与二尖瓣有效反流口面积之间存在线性关系。这些患者被指定为具有比例性 MR，对导致 LV 重构逆转和 LV 容积减少的治疗反应良好（例如神经激素拮抗剂和 LV 辅助装置），但他们可能不会从仅针对二尖瓣瓣叶的干预措施中获益（例如，经导管二尖瓣修复）。相比之下，当心室不同步导致由于乳头肌收缩不均引起的功能性 MR 时，反流程度大于 LV 容积预测的程度。这些患者被指定为具有严重但不成比例的 MR，对针对二尖瓣瓣叶或其支持结构的治疗（例如心脏再同步或经导管二尖瓣修复）反应良好，但他们可能从仅作用于减小 LV 腔大小的干预措施中获益甚微（例如药物治疗）。这个新的概念框架反映了 LV 几何形状和二尖瓣功能之间的重要相互作用，在确定患者的临床表现方面具有重要意义，并允许对功能性 MR 的决定因素进行特征描述，以指导临床环境中的最适当治疗。
