Prognostic Significance of Ischemic Mitral Regurgitation on Outcomes in Acute ST-Elevation Myocardial Infarction Managed by Primary Percutaneous Coronary Intervention

Ischemic mitral regurgitation (IMR) has been associated with worse outcome myocardial infarction. However, severity of mitral regurgitation (MR) and its impact on patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) remains unknown. We sought to determine impact of increasing severity of IMR on outcomes in patients with STEMI undergoing primary PCI. All patients presenting with STEMI who underwent primary PCI within 12 hours of symptoms from 1994 to 2014 were included. IMR was graded from 0 to 4+ within 3 days of index myocardial infarction by echocardiography. Overall, 4,005 patients with STEMI were included. None, 1+, 2+, 3+, and 4+ MR were present in 3,200 (79.9%), 427 (10.7%), 260 (6.5%), 91 (2.3%), and 27 (0.7%) patients, respectively. On multivariate logistic regression analysis, more severe MR was associated with older age, female gender, lower body mass index, anemia, inferior STEMI, and longer door-to-balloon time. The 30-day mortality rates were 6.8%, 7.3%, 8.8%, 19.8%, and 26.1%, respectively, with increasing grade of MR. The 1-year mortality rates were 10.8%, 12.4%, 20.8%, 37.4%, and 37.1%, whereas 5-year mortality rates were 16.2%, 23.1%, 36.5%, 53.8%, and 63%, respectively (p <0.001 all), for none to 4+ MR. After adjusting for age, gender, co-morbidities, ejection fraction, and shock by multivariate analysis, severity of IMR was associated with incremental effect on long-term mortality (hazard ratios of 1.42, 1.83, 2.41, and 2.95 for 1+ to 4+ MR respectively, p <0.01 for all). In conclusion, higher grades of MR in patients with STEMI undergoing primary PCI are associated with worse short- and long-term outcomes.