On-Hours Versus Off-Hours Primary PCI for STEMI: Outcomes in a Real-World Tertiary Hospital Cohort

Background: Primary Percutaneous Coronary Intervention (pPCI) is the preferred reperfusion strategy in ST-elevation myocardial infarction (STEMI). However, concerns remain regarding potential delays and adverse outcomes during off-hours (nights, weekends, and holidays). This study compared clinical outcomes between on-hours and off-hours pPCI, focusing on Door-to-Balloon (D2B) time and Major Adverse Cardiovascular Events (MACE).Methods: We conducted a single-center retrospective cohort study of consecutive patients with ST-Elevation Myocardial Infarction (STEMI) who underwent pPCI at Harapan Kita National Cardiovascular Center, Jakarta, Indonesia, between January 2023 and April 2024. On-hours were weekdays 08:00–20:00; all other times were off-hours. Only hemodynamically stable STEMI patients were included. The primary outcome was D2B (D2B) time, and the secondary outcome was 1-year MACE, defined as a composite of urgent revascularization, recurrent myocardial infarction, cardiovascular death, or stroke/Transient Ischemic Attack (TIA). Continuous variables were compared using the Mann–Whitney U test, and categorical variables using the chi-square test. Logistic regression analysis was performed to assess the association between off-hours PCI and clinical outcomes.Results: Among 287 patients, 98 presented during on-hours and 189 during off-hours. Baseline age was similar (median 55–56 years). Median D2B time was shorter on off-hours: 80 [Interquartile Range (IQR) 70–104] vs 89 [74–121] minutes (p=0.018). The proportion achieving D2B <90 minutes did not differ (63.5% vs 58.2%; p=0.443). At 1 year, MACE rates were comparable (14.8% off-hours vs 17.3% on-hours, p=0.576), with no significant differences across individual components.Conclusions: In this real-world cohort from a tertiary cardiac hospital in Indonesia, off-hours presentation was associated with faster D2B times and no increase in 1-year MACE, suggesting consistent quality and efficiency of STEMI care across all hours.