Left ventricle-mitral valve ring size mismatch: understanding the limitations of mitral valve repair for ischemic mitral regurgitation

There are 750,000 patients diagnosed with a myocardial infarction in the United States yearly, of which approximately 25% will develop an ischemic cardiomyopathy complicated by significant mitral regurgitation (MR) (1,2). The occurrence of ischemic MR is associated with significant morbidity and mortality, which increases commensurate with the MR severity (2). It is caused by the abnormal mitral valve geometry that develops after the onset of left ventricular (LV) remodeling and dilatation, which results in posterolateral and apical papillary muscle displacement, impaired systolic shortening of the interpapillary muscle distance, and mitral valve leaflet tethering (3,4). The subsequent disruption of the mitral valve closing-tethering forces leads to an incomplete systolic mitral valve closure and the development of ischemic MR. A dilated mitral annulus is also a common finding; however, its role in the development versus exacerbation of ischemic MR, is not clearly defined (4,5).