Prognostic importance of mitral regurgitation complicated by acute myocardial infarction during a 5-year follow-up period in the drug-eluting stent era

BACKGROUND: Mitral regurgitation (MR) is a frequent complication of left-ventricular dysfunction, with an incidence ranging from 13 to 59% after acute myocardial infarction (AMI), which is associated with poor clinical outcome. The aim of this study was to assess the clinical and angiographic characteristics associated with MR, the incidence and predictors of MR, and the outcomes of MR after AMI in those who were successfully treated with primary percutaneous coronary intervention (PCI) using a drug-eluting stent. METHODS: We analyzed a multicenter all-comer AMI registry and identified 4748 patients between January 2004 and December 2009. Of these, 1894 patients were treated with PCI using a drug-eluting stent and had MR. The association between MR and the composite of major adverse cardiac and cerebrovascular events (MACCE; all-cause death, recurrent nonfatal myocardial infarction, stroke, and any revascularization) was examined. RESULTS: Patients with MR after the index PCI showed significantly higher cumulative incidence of MACCE compared with no-MR patients over the 5-year survival period (P=0.002). When the MR groups were compared on the basis of the severity of MR, ranging from mild to severe grades, a higher grade of MR was found to be associated with a higher incidence of MACCE (P<0.001). Multivariate Cox proportional hazard analysis revealed that no reflow, left-ventricular ejection fraction less than 50%, and anemia, in addition to MR, were consistently associated with increased all-cause death during the 5-year period (adjusted hazard ratio 1.408, 95% confidence interval 1.052-1.884, P=0.021). CONCLUSION: MR after AMI in patients successfully treated with primary PCI was associated with poor long-term outcome regardless of ST-segment elevation at diagnosis during the drug-eluting stent era.