Renin-angiotensin system inhibitors and non-ST-elevation myocardial infarction outcomes based on left ventricular ejection fraction.

Background: We assessed left ventricular ejection fraction (LVEF) to compare the effects of renin-angiotensin system inhibitors (RASI) in patients with non-ST-segment elevation myocardial infarction (NSTEMI).

Methods: We categorized 4558 patients with NSTEMI as either RASI users (3752 patients) or non-users (806 patients). The 3-year patient-oriented composite outcome (POCO), which included all-cause death, recurrent myocardial infarction, any repeat revascularization, or hospitalization for heart failure (HF), was the primary outcome. To compare clinical outcomes, a multivariable-adjusted hazard ratio (aHR) was calculated after performing multicollinearity tests on all significant confounding variables (P < 0.05).

Results: Among RASI users, the aHRs for POCO, all-cause death, and cardiac death were significantly higher in the HF with reduced EF (HFrEF) subgroup than in the HF with mildly reduced EF (HFmrEF) (1.610, 2.120, and 2.489; P < 0.001, <0.001, and <0.001; respectively) and HF with preserved EF (HFpEF) (2.234, 3.920, and 5.215; P < 0.001, <0.001, and <0.001; respectively) subgroups. The aHRs for these variables were significantly higher in the HFmrEF subgroup than the HFpEF subgroup (1.416, 1.843, and 2.172, respectively). Among RASI non-users, the aHRs for these variables were significantly higher in the HFrEF subgroup than the HFmrEF (2.573, 3.172, and 3.762, respectively) and HFpEF (2.425, 3.805, and 4.178, respectively) subgroups. In three LVEF subgroups, RASI users exhibited lower aHRs for POCO and all-cause death than RASI non-users.

Conclusion: In the RASI users group, the aHRs for POCO and mortality were highest in the HFrEF subgroup, intermediate in the HFmrEF subgroup, and lowest in the HFpEF subgroup.