Abstract
Due to limited published data, we investigated 3-year outcomes according to left ventricular ejection fraction (LVEF) in patients older and younger than 75 years with non-ST-segment elevation myocardial infarction (NSTEMI) who underwent successful newer-generation drug-eluting stent (DES) implantation. This research analyzed the data of 4558 patients (1032 older adults [≥75 years] and 3526 younger adults [<75 years]) from the Korea Acute MI Registry-NIH. We further divided the older group based on LVEF: heart failure (HF) with reduced EF (HFrEF, ≤40%, n = 196; group A), HF with mildly reduced EF (HFmrEF, 41-49%, n = 228; group B), and HF with preserved EF (HFpEF, ≥50%, n = 608; group C). Similarly, the younger group was divided into HFrEF (group D, n = 353), HFmrEF (group E, n = 577), and HFpEF (group F, n = 2596). The primary outcome was a composite of major adverse cardiac events (MACE) at 3 years, including all-cause death, recurrent MI, any repeat revascularization, or hospitalization for HF. MACE rates were highest in the HFrEF groups (A and D), followed by the HFmrEF groups (B and E), and lowest in the HFpEF groups (C and F) for both age groups. All-cause death, cardiac death (CD), all-cause death or MI, and hospitalization for HF rates were higher in group A than in groups B and C, and higher in group D than in groups E and F. Across all LVEF categories, MACE, all-cause death, CD, and non-CD, and all-cause death or MI rates were higher in the older group. This multicenter cohort study demonstrates that older patients have higher mortality rates compared to younger patients. Additionally, MACE rates were highest in the HFrEF group, followed by the HFmrEF group, and lowest in the HFpEF group across both age groups. Further research is needed to confirm these findings.