What to do about ischemic mitral regurgitation?

M itral regurgitation (MR) can be classified as either degenerative or functional. Degenerative MR is due to disease, deformity, or damage of the mitral valve or its supporting apparatus. Functional MR is caused by improper coaptation of normal leaflets and apparatus and is due primarily to abnormalities of the left ventricle. Ischemic MR is a subset of functional MR (papillary muscle rupture, a mechanical complication of acute myocardial infarction [MI], is a rare exception). MR is commonly observed in patients with heart failure, recent or remote MI, and ischemic cardiomyopathy. The prevalence ranges from 10% to 70% (1). This broad range is due to differences in the method used to define MR, the population studied, and the time frame after MI that analysis was performed. Although the exact prevalence is unknown, some degree of MR is clearly common. Most patients have mild regurgitation. Moderate to severe regurgitation is reported in 10% to 20% of patients with ischemic heart disease (2–5). MR is also seen after non– ST-segment elevation myocardial infarction with 1 report observing MR in 40% of non–ST-segment elevation myocardial infarction patients with <5% exhibiting severe MR (6). The presence of MR in patients with ischemic heart disease is a powerful predictor of adverse events (2–4,7). An analysis of 303 patients several weeks after transmural infarction found some degree of MR in 64% of patients (2). Patients with MR had a greater mortality than those without regurgitation and this was independent of other variables and was