Aim: Previous studies have shown contradictory outcomes in ST-segment elevation myocardial infarction (STEMI) patients who underwent primary percutaneous coronary intervention (pPCI) during off-hours versus regular 'office' hours. We aimed to evaluate the relationship between pPCI timing (off-hours versus regular hours) and mortality in patients with STEMI undergoing pPCI.
Methods: The study population comprised 4352 consecutive STEMI patients treated with pPCI in a high-volume centre with a 24/7 programme during 2000-2009. Descriptive statistics and multivariable survival analyses were applied to evaluate the relationship between treatment during off-hours (Monday-Friday, 6.00 pm-8.00 am and weekends) versus regular hours and the incidence of all-cause mortality at 30-day and 4-year follow-up.
Results: A total of 2760 patients (63.4%) were treated during off-hours and 1592 patients (36.6%) during regular hours. With the exception of smoking, diabetes mellitus, use of glycoprotein IIb/IIIa antagonists and calcium antagonists, no major differences in baseline characteristics were observed between the groups. Mortality at 30-day follow-up was similar in patients treated during off-hours and those treated during regular hours (7.7% vs 7.7%; hazard ratio adjusted for potential confounders 1.03; 95% CI 0.82-1.28). Four-year mortality was similar (17.3% vs 17.3%; adjusted hazard ratio 0.95; 95% CI 0.81-1.11).
Conclusion: In STEMI patients who present during off-hours in a high-volume centre with 24/7 service, pPCI provides similar survival as patients who were treated during regular hours.
Keywords: STEMI; off hours; outcome; primary percutaneous coronary intervention.