Percutaneous coronary intervention during on- and off-hours in patients with ST-segment elevation myocardial infarction.

Objective: There are conflicting data on the clinical outcomes of percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) based on the time of admission to the catheterization laboratory. Thus, we aimed to assess clinical outcomes in an unselected cohort of consecutive patients with STEMI treated with PCI during on-and-off hours of work.

Methods: A total of 99,783 patients were included in the analysis. Patients were divided using the most frequently used definition: On-hours (Monday-Friday 07:00 AM-04:59 PM); off-hours (Monday-Friday 05:00 PM-06:59 AM, Saturday, Sunday, and nonworking holidays) (37,469 matched pairs). To avoid potential preselection bias, a propensity score was calculated to compare on-and-off hour groups.

Results: Higher radiation doses were observed for PCIs performed during off-hours (1055.2(±1006.5) vs. 1081.6(±1003.25)[mGy] and p = 0.001). A similar prevalence of periprocedural complications was observed during on- and off-hours. However, there was a higher mortality rate during off-hours than during regular working hours (1.17% (439) vs. 1.49% (559) and p = 0.001).

Conclusions: Primary PCIs in STEMI performed during off-hours might be associated with a higher rate of periprocedural mortality and higher radiation doses than procedures conducted during regular working hours.