Off-Hours Presentation, Door-to-Balloon Time, and Clinical Outcomes in Patients Referred for Primary Percutaneous Coronary Intervention

Objectives. Presentation with ST -segment -elevation myocardial infarction (STEMI) during off -hours may impact timely reperfusion and clinical outcomes. We investigated the association between off -hours presentation, door -to -balloon time, and in -hospital mortality in patients with STEMI referred for primary percutaneous coronary intervention (PCI). Methods.We included consecutive patients referred for primary PCI at the University of Ottawa Heart Institute between July 2004 and December 2017. The off -hours group included patients presenting on weekends, statutory holidays, or between 18:00 to 07:59 hours on weekdays. The on -hours group included patients presenting between 08:00 and 17:59 hours on weekdays. The primary clinical outcome was the adjusted inhospital mortality. The primary quality -of -care indicator was door -to -balloon time. Results. A total of 5132 patients were included, with 3152 (61.4%) in the off -hours group and 1980 (38.6%) in the on -hours group. The median door -to -balloon time was longer in the off -hours group compared with the on -hours group (102 minutes vs 77 minutes; P<.001), while the median onset -to -door time was similar (P=.40). There was no difference in the rates of in -hospital mortality (3.5% vs 3.0%; P=.32) or in the adjusted mortality (odds ratio, 1.2; 95% confidence interval, 0.8-1.8; P=.44) between off -hours and on -hours groups. However, door -to -balloon time was an independent predictor of in -hospital mortality (P<.01) and off -hours presentation was an independent predictor of longer door -to -balloon time (P<.001), with an excess of 22.1 minutes. Conclusion. Patients treated with primary PCI during off -hours had longer door -to -balloon times. Treatment during off -hours was an independent predictor of longer door -to -balloon time and longer door -to -balloon times were associated with higher mortality.