Long-term outcomes in ST-elevation myocardial infarction patients treated according to hospital visit time

BACKGROUND/AIMS: Rapid percutaneous coronary intervention (PCI) is the cornerstone of treatment for ST-elevation myocardial infarction (STEMI). However, there have been conflicting results regarding the differences in clinical outcomes between on-hours and off-hours presentation in STEMI patients. We aimed to examine the difference in long-term outcomes between off-hours and on-hours PCI in patients with STEMI. METHODS: The characteristics and clinical outcomes of 5,364 STEMI patients between November 2011 and June 2015 from the Korea Acute Myocardial Infarction Registry-National Institutes of Health (KAMIR-NIH) registry were analyzed. Patients were divided into two groups: the off-hours group (weekdays from 6:01 PM to 7:59 AM, weekends, and legal holidays) and the on-hours group (weekdays from 8:00 AM to 6:00 PM). Major adverse cardiac and cerebrovascular events (MACCEs) were defined as a composite of all-cause mortality, non-fatal myocardial infarction, any revascularization, cerebrovascular accident, and stent thrombosis. The primary endpoint was the occurrence of MACCEs, and all other clinical outcomes were analyzed. RESULTS: A total of 3,119 patients (58.1%) underwent primary PCI due to STEMI during off-hours and 2,245 patients (41.9%) during on-hours. At 36 months, the clinical outcomes of the off-hours group were similar to those of the on-hours group in both the unadjusted and propensity score weighting-adjusted analyses. CONCLUSIONS: Our analysis revealed that the long-term outcomes in STEMI patients admitted to hospitals during off-hours were similar to outcomes of those admitted during on-hours.