Time course and prognostic implications of significant mitral regurgitation after ST-segment elevation myocardial infarction

Abstract

Purpose: Ischemic mitral regurgitation (MR) is a well-known complication of ST-segment elevation myocardial infarction (STEMI). However, only a few studies so far evaluated MR during follow-up after STEMI. Accordingly, the aim of the current study was twofold: 1) to evaluate the changes over time in MR after STEMI and the prevalence of significant MR (defined as grade ≥2) at 1 year follow-up; and 2) to determine the prognostic implications of significant MR at follow-up. Methods: A total of 1,599 consecutive STEMI patients (77% male; 60±12 years) treated with primary percutaneous coronary intervention underwent echocardiography <48 hours of admission and at 1 year follow-up. MR grade was assessed according to current recommendations. Moreover, data on all-cause mortality were collected during long-term follow-up. Results: At baseline, significant MR was present in 103 patients (6%). At 1 year follow-up, MR improved ≥1 grade in 315 patients (20%), of whom 10 maintained a significant MR (with a decrease from MR grade 3 to grade 2). MR grade remained stable in 963 patients (60%), of whom 11 showed still significant MR. Moreover, MR worsened ≥1 grade over time in 321 patients (20%), of whom 114 progressed to significant MR. Consequently, significant MR was present in a total of 135 patients at 1 year (8%, P=0.01 compared to baseline). Furthermore, 399 patients (25%) showed significant left ventricular remodeling (defined as ≥15% increase in left ventricular end-systolic volume) at 1 year. During a median follow-up of 49 months, 121 patients (8%) died. Significant MR at 1 year was an independent predictor of all-cause mortality (HR 1.65, 95% CI 1.02-2.66), together with age (HR 1.06, 95% CI 1.04-1.08), multivessel disease (HR 1.73, 95% CI 1.16-2.58), diabetes (HR 1.88, 95% CI 1.18-2.99) and with a borderline significance of left ventricular remodeling (HR 1.47, 95% CI 0.99-2.17). Conclusions: The grade of MR changes over time after STEMI and significant MR was observed in 8% of STEMI patients at 1 year follow-up. Furthermore, significant MR at 1 year was independently associated with all-cause mortality.