Does on- versus off-hours presentation impact in-hospital outcomes of ST-segment elevation myocardial infarction patients transferred to a tertiary care center?

Objectives: To determine whether in-hospital outcome differs for transferred patients with ST-segment elevation myocardial infarction (STEMI) presenting during business (ON) hours vs. after (OFF) hours.

Background: Door-to-device (DTD) time is a prognostic factor in patients with STEMI and is longer during OFF hours. However, the in-hospital mortality is controversial.

Methods: This registry study included 786 consecutive patients with STEMI referred for primary percutaneous coronary intervention to a tertiary care center with an on-site cardiac catheterization team 24 hrs a day/7 days (24/7) a week. ON hours were defined as weekdays 8 a.m. to 5 p.m., while OFF hours were defined as all other times, including holidays. The primary outcomes were in-hospital death, reinfarction, and length of stay (LOS).

Results: ON hours (29.5%, n = 232) and OFF hours (70.5%, n = 554) groups had similar demographic and baseline characteristics. A significantly higher proportion of patients presenting ON hours had a DTD time ≤120 min compared to OFF hours patients (32.6% vs. 22.1%, P = 0.007). The rates of in-hospital death (8.2% vs. 6%), reinfarction (0% vs. 1.1%), and mean LOS (5.7 ± 6 vs. 5.7 ± 5) were not significantly different in the ON vs. OFF hours groups, all P = nonsignificant.

Conclusion: In a tertiary care center with an on-site cardiac catheterization team 24/7, there are no differences in in-hospital outcomes of transferred patients with STEMI during ON vs. OFF hours.