Door-to-Balloon Time and Clinical Outcome of Patients Presenting with ST-Segment Elevation Myocardial Infarction During on and off Hours: a Single Center Study.

Background: Timely reperfusion is crucial in patients with ST-segment elevation myocardial infarction (STEMI), with door-to-balloon time often considered a key metric for assessing quality of care. However, the impact of door-to-balloon time on clinical outcomes during off-hours remains uncertain. Objective: To compare clinical outcome and door-to-balloon time of patients with STEMI in off-hours versus on-hours in King Fahad Uni-versity Hospital (KFHU). Methods: A mixed-method, qualitative and quantitative retrospective cohort study was conducted at KFUH in Al Khobar, Saudi Arabia, including adults diagnosed with STEMI and managed with primary percutaneous coronary intervention (PCI) between May 2023 to February 2024. The sample was divided into two groups based on-duty hours. The first group comprised patients presenting during duty hours, including weekdays (Sunday to Thursday, 8 a.m. - 4 p.m.), while the second group included patients presenting during off-duty hours, which consisted of weekdays (Sunday to Thursday, 4:01 pm to 7:59 am), weekends (Friday to Saturday), national holidays, and Eid holidays. Results: The study included 79 patients (57 off-hours and 22 in-hours) diagnosed with STEMI who underwent primary PCI. The mean age of the participants was 55.0 years (±10.8), 89.9% were males, 36.7% were Saudi, and 41.8% were smokers. Off-hours presentation did not significantly impact mortality rates or complications compared to on-hours presentation (p > 0.05), Similarly, no significant association was found between door-to-balloon time and 48-hour or 30-day mortality rates (p > 0.05). The mean time was statistically significant across the on- and off-duty time groups (65.2±18.0 vs 107.4±44.5, p<0.0001). Hypotension was the only complication signifi-cantly associated with mortality at 30 days (p < 0.001). Conclusion: Our results revealed that neither door-to-balloon time nor off-hours presentation significantly affected mortality rates or complications in pa-tients with STEMI undergoing Primary PCI, with the exception of hypotension being significantly associat-ed with 30-day mortality. Further research is warranted to explore other factors that may influence STEMI outcomes beyond door-to-balloon time and presentation hours. Additionally, investigating the specific rela-tionship between hypotension and 30-day mortality could lead to improved risk stratification and manage-ment strategies for STEMI patients.