Results of Primary Percutaneous Coronary Interventions Performed During On- and Off-Hours

BackgroundPrevious studies have shown that primary percutaneous coronary interventions carried off-hours are related to a worse prognosis. The objective of this study was to evaluate the outcomes of patients undergoing on- and off-hours primary percutaneous coronary interventions performed at a reference cardiology center.MethodsProspective cohort study, including 1,108 consecutive patients with ST elevation myocardial infarction divided into a group of primary percutaneous coronary intervention performed during regular working hours (on-hours: 8:00am to 8:00pm) and primary percutaneous coronary intervention during non-regular working hours group (off-hours: 8:00pm to 8:00am).ResultsThe sample included 680 patients in the on-hours group and 428 in the off-hours group. Baseline demographic data, risk factors and Killip classification were similar in both groups; however door-to-balloon time was significantly longer in the off-hours group (84 ± 66 minutes vs. 102 ± 98 minutes; p < 0.01). Culprit vessels and pre- and post-procedure TIMI flows were not different between groups. There were no significant differences for in-hospital mortality (7.6% vs. 10.2%; p = 0.16), stent thrombosis (2.8% vs. 2.4%; p = 0.69) or major bleeding (1.9% vs. 2.1%; p = 0.50). One-year mortality was also similar (9.5% vs. 12.6%; p = 0.12). The main predictor of mortality at 1 year was Killip III/IV (OR, 10.02; 95% CI, 5.8-17.1; p < 0.01).ConclusionsPatients with myocardial infarction have similar in-hospital clinical outcomes regardless of the time when primary percutaneous coronary intervention is performed. However, door-to-balloon time is significantly longer in patients treated during off-hours.