Long‐Term Risk of Cardiovascular Death in Patients With Mildly Reduced Ejection Fraction After Acute Myocardial Infarction: A Multicenter, Prospective Registry Study

Abstract

Background The prognostic implication of mildly reduced ejection fraction (mrEF) after acute myocardial infarction has not been clearly demonstrated. We investigated the long‐term risk of cardiovascular death and its predictors in patients with mrEF following acute myocardial infarction. Methods and Results A total of 18 668 patients who presented with acute myocardial infarction were included in 2 prospective, multicenter registries. The incidence of adverse cardiovascular events according to the left ventricular ejection fraction (EF) strata at index admission were evaluated. A score system consisting of clinical variables were developed to predict long‐term cardiovascular death in the mrEF group. There were 2548 patients with reduced EF (EF ≤40%), 4266 patients with mrEF (EF 41%–49%), and 11 854 patients with preserved EF (EF ≥50%). During a median follow‐up period of 37.9 months, the cardiovascular death rate was 22.3% in the reduced EF group, 10.3% in the mrEF group, and 7.3% in the preserved EF group ( P <0.001). In the mrEF group, age>65 years, hypertension, stroke, severe renal insufficiency, and Killip class ≥3 were independent predictors for cardiovascular death. Presence of >2 predictors best discriminated the high‐risk patients for cardiovascular death with an area under the curve of 0.746. Incidence of cardiovascular death in the high‐risk mrEF group was comparable with the rEF group, while it was lower in the low‐risk mrEF group than in the pEF group. Conclusions Patients with mrEF after acute myocardial infarction had a modest risk of cardiovascular death. Clinical predictors could help discriminate a high‐risk subpopulation with cardiovascular death risks comparable with those in the reduced EF group.