On- vs. off-hours admission of patients with ST-elevation acute myocardial infarction undergoing percutaneous coronary interventions: data from a tertiary university Brazilian hospital

Introduction: Early reperfusion therapy is crucial in patients with ST-elevation myocardial infarction (STEMI). Off-hours hospital presentation may increase the time from pain to coronary reperfusion, and it may be responsible for increased cardiovascular outcomes. The aim of this study was to compare the effect of different times of presentation (on- and off-hours) on early mortality and major cardiovascular outcomes in patients with STEMI who underwent primary percutaneous coronary intervention (PCI). Methods: We have included consecutive patients with STEMI who underwent primary PCI between April 2011 and November 2016 in a tertiary university hospital in southern Brazil. Patients were divided into on- and off-hours admission. In-hospital and 30-day outcomes were evaluated. Results: A total of 301 patients (57.4%) were admitted during off-hours, and 223 (42.5%) during on-hours. Baseline characteristics were well balanced between the two groups. Median door-to-balloon time was higher in the off-hours group than in the on-hours group: 75 min (IQR 60-95) vs. 60 min (IQR 50-73.7) respectively (p < 0.001). In-hospital mortality was similar between groups (odds ratio [OR] = 0.56; 95% confidence interval [95%CI] 0.31-1.03; p = 0.06) and at 30-day follow-up (OR = 0.2; 95%CI 0.02-1.72 p = 0.14). In the matched cohort, no difference was found in the rates of in-hospital mortality (OR = 2.0; 95%CI 0.75-5.32; p = 0.16) and 30-day MACE (OR= 0.9; 95%CI 0.49-1.66; p = 0.75). Conclusions: In our center with PCI available 24/7 – without in-house staff – we did not observe any difference in patient characteristics, management, and outcomes, although a significant longer door-to-balloon time was found in patients treated during night shifts. Our results are consistent with those of other trials. Keywords: Myocardial infarction; percutaneous coronary intervention; system dela