Clinical Outcomes According to Revascularization Strategy in Patients With Late-Presenting ST-Segment Elevation Myocardial Infarction: A Retrospective Cohort Study

Background: Timely reperfusion remains the cornerstone of management in ST-segment elevation myocardial infarction (STEMI).However, a substantial proportion of patients continue to present beyond the recommended reperfusion window, particularly in low-and middle-income countries.The outcomes associated with delayed coronary revascularization in these late presenters remain incompletely defined.This retrospective observational study aimed to compare one-year mortality and left ventricular ejection fraction (LVEF) changes according to treatment strategy among STEMI patients presenting more than 12 hours after symptom onset.Methods: We conducted a retrospective observational cohort study including consecutive patients admitted with STEMI more than 12 hours after symptom onset between January 2020 and December 2025 at Mohammed VI University Hospital, Marrakech, Morocco.Patients were stratified according to treatment strategy into delayed percutaneous coronary intervention (PCI), conservative medical management, and coronary artery bypass grafting (CABG).The primary endpoint was one-year all-cause mortality, and the secondary outcome was change in LVEF.Mortality comparisons were unadjusted and should therefore be interpreted as descriptive associations rather than causal treatment effects.Results: A total of 479 patients were included.Delayed PCI was performed in 262 (54.7%) patients, conservative treatment was adopted in 121 (25.3%), and CABG was performed in 96 (20.0%).During available follow-up, 79 (16.5%) deaths were observed.Observed mortality was 19 (7.3%) in the PCI group, 41 (33.9%) in the conservative-management group, and 19 (19.8%) in the CABG-strategy group.Paired sixweek LVEF measurements showed an increase from 28 ± 7% to 47 ± 8% in the PCI group, from 35 ± 5% to 42 ± 4% in the conservative-management group, and from 23 ± 8% to 44 ± 5% in the CABG-strategy group.Conclusions: In this retrospective observational Moroccan cohort of late-presenting STEMI patients, treatment with delayed PCI or CABG was associated with lower unadjusted one-year mortality and greater improvement in LVEF than conservative medical management.Because treatment allocation was nonrandomized and mortality comparisons were unadjusted, these findings should not be interpreted as evidence of a causal mortality benefit from delayed revascularization.Further prospective studies are needed to clarify which late-presenting patients may benefit from an invasive strategy.