Ischemic functional mitral regurgitation: from pathophysiological concepts to current treatment options. A systemic review for optimal strategy.

OBJECTIVE The current treatment of ischemic functional mitral regurgitation (FMR) remains debated due to differences in inclusion criteria of randomized studies and baseline characteristics. Also, the role of left ventricular pathophysiology and the role of subvalvular apparatus have not been thoroughly investigated in recent literature. METHODS A literature search was performed from PubMed inception to June 2020. RESULTS Novel concepts of pathophysiology, such as the proportionate/disproportionate conceptual framework, the role of papillary muscles and left ventricular dysfunction, the impact of myocardial ischemia and revascularization, left ventricular remodeling, and the effect of restrictive annuloplasty or subvalvular procedures have been reviewed. CONCLUSIONS The clinical benefits associated with the use of MitraClip is more evident in patients with disproportionate FMR with greater and sustained left ventricular reverse remodeling. Importantly, in the absence of myocardial revascularization, expansion of myocardial scar tissue and non-perfused areas of ischemic myocardium occur with time, and this impact on outcomes with a longer follow-up period cannot be quantified. In advanced phases of FMR, neither mitral ring annuloplasty nor percutaneous therapies could significantly modify the established pathoanatomic alterations.