Clinical Significance of Mitral Regurgitation After Acute Myocardial Infarction

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Abstract
Background Mitral regurgitation (MR) may complicate acute myocardial infarction (MI). However, it is not known whether mild MR is an independent predictor of post-MI outcome. Methods and Results The study cohort consisted of 727 Survival and Ventricular Enlargement Study patients who underwent cardiac catheterization, including left ventriculography, up to 16 days after MI. Left ventriculograms were analyzed for diastolic and systolic volumes, global left ventricular sphericity, extent of wall motion abnormality, and endocardial curvature. The presence of MR was related to the risk of developing a cardiovascular event during 3.5 years of follow-up. MR was present in 141 patients (19.4%). Severe (3+) MR was present in only 2 patients. Patients with MR were more likely to have a persistently occluded infarct artery (MR versus no MR, 27.3% versus 15.2%; P=.001). Although the ejection fractions were similar, MR patients had larger end-systolic and end-diastolic volumes and more spherical ventricles than patients without MR. Sphericity change from diastole to systole was also significantly reduced in MR patients. Patients with MR were more likely to experience cardiovascular mortality (29% versus 12%; P<.001), severe heart failure (24% versus 16%; P=.0153), and the combined end point of cardiovascular mortality, severe heart failure, or recurrent myocardial infarction (47% versus 29%; P<.001). The presence of MR was an independent predictor of cardiovascular mortality (relative risk, 2.00; 95% CI, 1.28 to 3.04). Conclusions Mild MR is an independent predictor of post-MI mortality. As such, it adds important information for risk stratification of post-MI patients.