The Impact of Mitral Regurgitation on Long-Term Outcomes in Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention.

It is important to clarify the precise impact of mitral regurgitation (MR) on long-term outcomes in acute myocardial infarction (AMI) patients who underwent percutaneous coronary intervention (PCI). In the Coronary Revascularization Demonstrating Outcome study in Kyoto Acute Myocardial Infarction (CREDO-Kyoto AMI) Registry Wave-2, the study population consisted of 5,266 patients with AMI who underwent PCI. The clinical outcomes of all-cause death, cardiovascular death, and hospitalization for heart failure (HF) were compared according to the severity of MR. Mild and moderate/severe MR were identified in 2,112 (40%) and 531 patients (10%), respectively. Patients with greater severity of MR were more likely to be old, had more co-morbidities, and more often presented with large myocardial infarction with HF. During median follow-up duration of 5.6 (interquartile range: 4.2 to 6.6) years, as the MR severity increased from no, mild, to moderate/severe MR, the cumulative 5-year incidences of all-cause death, cardiovascular death and hospitalization for HF incrementally increased ([15.3%, 19.6%, 33.3%], [8.9%, 11.7%, 21.0%] and [5.9%, 12.4%, 23.9%], respectively, P for all<0.001). After adjusting for confounders, however, mild and moderate/severe MR were not independently associated with the higher risks for all-cause death (hazard ratio [95% confidence interval]:1.05 [0.92 to 1.19], p = 0.51, and 1.10 [0.92 to 1.32], p = 0.28) and cardiovascular death (1.01 [0.85 to 1.21], p = 0.89, and 0.93 [0.73 to 1.18], p = 0.54) as compared with no MR. Both mild and moderate/severe MR were independently associated with the higher risks for hospitalization for HF (1.73 [1.42 to 2.11], p <0.001, and 2.23 [1.73 to 2.87], p <0.001). In a large population of patients with AMI who underwent PCI, MR was not independently associated with higher long-term mortality risk but was independently associated with higher risk for hospitalization for HF.