Prognostic Impact of Renin–Angiotensin System Inhibitors in Revascularized Patients with Acute Myocardial Infarction and Preserved or Mildly Reduced Ejection Fraction: A Retrospective Cohort Study

Background: The prognostic value of discharge renin–angiotensin–aldosterone system inhibitor (RASi) therapy in contemporary PCI-treated acute myocardial infarction (AMI) survivors with preserved or mildly reduced left ventricular ejection fraction (LVEF) remains uncertain. Methods: A retrospective cohort study of 2530 AMI patients (2019–2022) stratified by RASi use. Exclusion criteria were in-hospital mortality, LVEF < 40%, contraindications to the use of RASis or no percutaneous coronary intervention (PCI). Primary endpoints included heart failure (HF) events, recurrent acute coronary syndrome (ACS), and all-cause mortality. Kaplan–Meier analyses and inverse probability of treatment weighting (IPTW)-weighted Cox models were applied. Results: Over a mean follow-up of 49 months, discharge RASi therapy was not associated with all-cause mortality overall, but was associated with fewer HF rehospitalizations (HR 0.62, 95% CI 0.40–0.95; p = 0.03). Mortality associations differed by AMI type and hypertension status, particularly for NSTEMI (HR 0.36, 95% CI 0.14–0.91; p = 0.03; p for interaction = 0.02) and hypertension (HR 0.36, 95% CI 0.15–0.84; p = 0.02; p for interaction = 0.04). Conclusions: In this single-center observational cohort of PCI-treated AMI survivors with LVEF ≥ 40%, discharge RASi therapy was associated with fewer HF rehospitalizations but not with lower overall mortality. Exploratory subgroup analyses suggested potential heterogeneity according to NSTEMI status and hypertension, but these findings should be considered hypothesis-generating and require confirmation.