One-year mortality of primary angioplasty for acute myocardial infarction during regular working hours versus off-hours

Randomised clinical trials have shown the superiority of primary percutaneous coronary intervention (PPCI) over fibrinolysis therapy in terms of better event-free survival and clinical outcomes in patients with acute ST-elevation myocardial infarction (STEMI).
However, there has been concern as to whether STEMI patients who are admitted during off-hours (week nights, weekends, and holidays) to undergo PPCI might have higher mortality than patients admitted during regular “office” hours. The mortality difference is thought to be due to the variations in door-to-device (DTD) time, door-to-ECG time, awareness of the alarm centre staff, physician performance, and the numbers of staff in the catheterisation laboratory and intensive cardiovascular care unit. On the other hand, the establishment of a STEMI network may narrow these disparities, resulting in similar outcomes regardless of the time of the patient’s presentation.

While prior studies have shown contradictory outcomes in STEMI patients who underwent PPCI during off-hours versus regular office hours, most of the studies did not evaluate the long-term outcomes. Moreover, many of these studies included several centres, and results from hospitals with poor STEMI processes may offset those from leading centres (i.e., “regression to the mean”). In this context, data from a single centre may provide value by providing an example of “best practices” for PPCI if outcomes are similar between off-hours and on-hours patients. We evaluated the relationship between timing of admission of STEMI patients (off-hours versus regular hours) and long-term mortality of STEMI patients treated with PPCI in a tertiary care academic teaching hospital.