Comparison of clinical outcomes in patients with ST-segment elevation myocardial infarction among preserved, mid-range, and reduced ejection fraction.

The impact of mid-range (mr) ejection fraction (EF) on long-term clinical outcomes has been reported in patients with heart failure but remains unclear in patients with ST-segment elevation myocardial infarction (STEMI). The purpose of this study was to compare the long-term clinical outcomes among STEMI patients with preserved EF (pEF), mrEF, and reduced EF (rEF), and to evaluate the significance of mrEF as a prognostic factor for patients with STEMI. We included 705 patients with STEMI and divided them into rEF group (n = 155), mrEF group (n = 155), and pEF group (n = 395) according to the pre-discharge EF. The primary endpoint was the major adverse cardiovascular events (MACE), which were defined as the composite of all-cause death, re-admission for heart failure, and non-fatal myocardial infarction (MI). The median follow-up duration was 906 days (Q1:349.5-Q3:1479). The Kaplan-Meier curves showed that MACE and re-admission for heart failure were more frequently observed in the rEF group, followed by the mrEF group, and least in the pEF group (p < 0.001). The multivariate Cox hazard analysis revealed that mrEF as well as rEF were significantly associated with MACE after controlling for confounding factors [rEF: hazard ratio (HR) 2.333, 95% confidence interval (CI) 1.350-4.034, p = 0.002, mrEF:HR1.852, 95%CI 1.139-3.010, p = 0.013]. Mid-range EF as well as rEF was significantly associated with MACE and re-admission for heart failure in patients with STEMI. Our results suggest that mrEF is an important prognostic factor in patients with STEMI.