Admission During Off-Hours Does Not Affect Long-Term Clinical Outcomes of Japanese Patients with Acute Myocardial Infarction J-MINUET Substudy

Discordant results have been reported on outcomes of acute myocardial infarction (AMI) patients who present during off-hours. We investigated 3283 consecutive patients with AMI who were selected from the prospective, nationwide, multicenter registry (J-MINUET) database comprising 28 institutions in Japan between July 2012 and March 2014 to determine the current impact of off-hours presentation (defined as weekends, holidays, and weekdays from 8:01 PM to 7:59 AM) at hospitals on long-term clinical outcomes. The primary endpoint was a composite of all-cause death, non-fatal MI, non-fatal stroke, cardiac failure, and urgent revascularization for unstable angina for up to 3 years from the index event. During off-hours, 52% of patients presented. Primary percutaneous coronary intervention was performed in 85% of patients, and the door-to-balloon time was comparable between off-hours and regular hours (74, interquartile range [IQR] 52 to 113 versus 75, IQR 52 to 126 minutes, P = 0.34). Rate of overall primary endpoint overall did not overall significantly differ (25.3% versus 23.5%, log-rank P = 0.26), in patients with ST- elevation myocardial infarction (STEMI) (log-rank P = 0.93) and in patients with non-ST-elevation myocardial infarction (NSTEMI) (log-rank P = 0.14). Multivariate Cox regression analysis showed that off-hours presentation was not significantly associated with long-term clinical events in all cohorts. The impact of presentation during off-hours or regular hours on the long-term clinical outcomes of Japanese patients with AMI is comparable in contemporary practice.