Physiologic basis for the surgical treatment of ischemic mitral regurgitation.

Ischemic mitral regurgitation (MR) can complicate severe coronary artery disease and myocardial infarction. Ischemic MR results from left ventricular remodeling after myocardial infarction and can also accompany acute myocardial ischemia. The most common mechanism of ischemic MR is Carpentier's type IIIb dysfunction due to an apical and lateral displacement of papillary muscles leading to a tethering of the mitral leaflets. This apical tenting of the leaflets prevents the free margin from reaching the plane of the annulus, significantly reduces the surface of coaptation, and causes MR. Recent advances in imaging studies have led to a better understanding of the pathophysiology of this condition as well as to the development of innovative surgical approaches to treat this disease. Current research efforts have mainly focused on 2 directions: (1) percutaneous approaches to correct MR, and (2) surgical therapy to address the ventricular component of the disease. In this article, the authors define ischemic MR and review its pathophysiology, current management strategies, and future directions.