Time-Trend Analyses of Bleeding and Mortality After Primary Percutaneous Coronary Intervention During Out of Working Hours Versus In-Working Hours An Observational Study of 11 466 Patients

Background—Primary percutaneous coronary intervention (PPCI) is the treatment of choice for ST-segment–elevation myocardial infarction. Resources are limited during out of working hours (OWH). Whether PPCI outside working hours is associated with worse outcomes and whether outcomes have improved over time are unknown. Methods and Results—We analyzed 11 466 patients undergoing PPCI between 2004 and 2011 at all 8 tertiary cardiac centers in London, United Kingdom. We defined working hours as 9 am to 5 pm (Monday to Friday). We analyzed in-hospital bleeding and all-cause mortality ≤3 years, comparing OWH versus in-working hours. A total of 7494 patients (65.3%) were treated during OWH. Multivariable analyses demonstrated that PPCI during OWH was not a predictor for bleeding (odds ratio, 1.47; 95% confidence interval [CI], 0.97–2.24; P=0.071) or 3-year mortality (hazard ratio, 1.11; 95% CI, 0.94–1.32; P=0.20). This was confirmed in propensity-matched analyses. Time-stratified analyses demonstrated that PPCI d...