Mortality outcome of out-of-hours primary percutaneous coronary intervention in the current era

Aims To assess the impact of the time of primary percutaneous coronary intervention (PPCI) on in-hospital and long-term all-cause mortality in ST-segment elevation myocardial infarction (STEMI). Methods and results The study retrospectively analyses the prospectively collected data on 2571 consecutive PPCI-treated STEMI patients between March 2008 and June 2011. Of these, 1036 patients (40.3%) underwent PPCI during a weekday between 08: 00 and 18: 00 (routine-hours group) and 1535 patients (59.7%) underwent PPCI on a weekday between 18: 00 and 08: 00 or a weekend (out-of-hours group). Compared with the routine-hours group, the out-of-hours group had a lower mean age, fewer patients with previous angina, longer call-to-hospital time, and fewer multivessel PCI. The overall in-hospital mortality rate was 4.5% with no significant difference [0.2%, 95% confidence interval (CI): -1.4 to 1.9%] between the routine-hours group (4.3%) and the out-of-hours group (4.6%) (adjusted odds ratio: 1.33, 95% CI: 0.73-2.40, P = 0.35). During a mean follow-up period of 560 days, 295 patients (11.5%) died, 12.2% in the routine-hours group and 11.0% in the out-of-hours group (difference of -0.1%, 95% CI: -0.4 to 0.2%). In the multiple Cox proportional hazards model, there was no difference in mortality between the two groups (adjusted hazard ratio: 1.09, 95% CI: 0.82-1.46, P = 0.57). Similarly, no increase in mortality was seen in patients who underwent PPCI later at night (22:00-06:00). Conclusion This study of real-world, unselected STEMI patients demonstrates that in a large, well-staffed centre, PPCI outside routine-working hours is safe with no difference in outcome of in-hospital and long-term mortality compared with PPCI during routine-working hours.