Prognostic value of E/e' ratio and its change over time in ST-segment elevation myocardial infarction with preserved left ventricular ejection fraction in the reperfusion era.

BACKGROUND: The ratio of early diastolic mitral inflow velocity to mitral annular velocity (E/e') is a prognostic factor in patients with ST-segment elevation myocardial infarction (STEMI). However, data are lacking on long-term outcomes and longitudinal changes in E/e' in patients with preserved left ventricular ejection fraction (LVEF) in the reperfusion era.

METHODS: This is a pre-specified echocardiographic substudy of a randomized controlled trial evaluating the efficacy of beta-blockers in STEMI patients with LVEF ≥40 % after primary percutaneous coronary intervention (PCI). Patients were divided into 2 groups according to E/e' at discharge: ≤14 (normal E/e' group) or > 14 (high E/e' group). The primary outcome was a composite of all-cause death, myocardial infarction, stroke, acute coronary syndrome, and heart failure hospitalization. We also assessed longitudinal changes in E/e' and conducted a landmark analysis using E/e' at 1 year after STEMI.

RESULTS: There were 173 and 38 patients in the normal and high E/e' groups, respectively. During a median follow-up of 3.9 years, the primary outcome occurred in 19 patients (11.0 %) and 10 patients (26.3 %) in the normal and high E/e' groups, respectively. The cumulative incidence of the primary outcome was higher in the high E/e' group than in the normal E/e' group (21.9 % vs. 7.1 % at 3 years; log-rank p = 0.013). E/e' in the high E/e' group decreased over time (p < 0.001), but remained higher than in the normal E/e' group at 1 year after STEMI (13.7 ± 5.3 vs. 8.6 ± 2.3, p < 0.001). E/e' > 14 at 1 year was also associated with poor outcomes (log-rank p = 0.008). A sensitivity analysis using multivariate Cox proportional hazards regression models yielded consistent results.

CONCLUSION: High E/e' at discharge is associated with poor long-term outcomes in STEMI patients with preserved LVEF after primary PCI, which may be explained by persistent high E/e' late after STEMI.