Off-hours presentation does not affect in-hospital mortality of Japanese patients with acute myocardial infarction: J-MINUET substudy.

Background: The association between patients with acute myocardial infarction (AMI) who present during off-hours and clinical outcomes has not been fully elucidated.
Methods: We investigated 3283 consecutive patients with AMI who were selected from a 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 on in-hospital mortality among Japanese patients with AMI.
Results: Among the patients, 52% presented in off-hours. Baseline characteristics were comparable, although those who presented during off-hours were younger and had a higher incidence of ST-elevation myocardial infarction and advanced Killip Class. The time from symptom onset to presentation time was shorter in off-hour patients (120min, interquartile range 60 to 256 vs. 215min, interquartile range 90 to 610, p<0.0001). In contrast, 85% of patients underwent primary percutaneous coronary intervention (PCI) and door to balloon time was comparable between the groups (74min, interquartile range 52 to 113 vs. 75min, interquartile range 52 to 126, p=0.34). The rates of in-hospital mortality were comparable (6.2% vs 6.8%, p=0.39). Multivariate logistic regression analysis revealed that off-hours presentation was not significantly associated with in-hospital mortality [odds ratio (OR) 0.94; 95% CI, 0.68-1.30, p=0.70].
Conclusion: The clinical impact of presenting during off-hours or regular hours on AMI patients in Japan is comparable in contemporary practice.
Trial Registration: UMIN Unique trial Number: UMIN000010037.
(Copyright © 2017 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)