Timing of Complete Revascularization Stratified by Index Presentation During On- and Off-Hours

Recent trials suggested immediate complete revascularization (ICR) as a safe alternative to staged complete revascularization (SCR), but the impact of the respective percutaneous coronary intervention strategies between on- versus off-hours is unclear. On-hours was defined as an index revascularization performed between 8:00 a.m. and 6:00 p.m., Monday to Friday, or else the procedure was defined as performed during off-hours. The primary end point consisted of a composite of all-cause mortality, myocardial infarction, unplanned ischemia-driven revascularization, and cerebrovascular events at 1-year follow-up. We used Cox regression models to relate randomized treatment with study end points. We evaluated multiplicative and additive interactions between on- versus off-hours and randomized treatment. The BIOVASC (Percutaneous Complete Revascularization Strategies Using Sirolimus Eluting Biodegradable Polymer Coated Stents in Patients Presenting With Acute Coronary Syndromes and Multivessel Disease) trial enrolled 1,097 and 428 patients during on- and off-hours, respectively. Patients randomized during off-hours were more likely to present with ST-segment elevation myocardial infarction (66.4% vs 29.5%, p <0.001). The composite primary outcome occurred in 8.4% and 10.1% of patients randomized to ICR and SCR, respectively, during on-hours (hazard ratio 0.80, 95% confidence interval 0.54 to 1.19). During off-hours, the primary composite outcome occurred in 5.4% and 7.7% in ICR and SCR (0.69, 95% confidence interval 0.32 to 1.46) with no evidence of a differential effect (interaction p_{multiplicative} = 0.70, p_additive = 0.56). No differential effect was found between treatment allocation and on- versus off-hours in any of the secondary outcomes. In conclusion, no differential treatment effect was found when comparing ICR versus SCR in patients presenting with acute coronary syndrome and multivessel disease during on- or off-hours.