Impact of door in-door out time on total ischemia time and clinical outcomes in patients with ST-elevation myocardial infarction.

INTRODUCTION: Patients with ST-elevation myocardial infarction (STEMI) requiring inter-hospital transfer for primary percutaneous coronary intervention (PCI) often have delays in reperfusion. The door in-door out (DIDO) time is recommended to be less than 30 min. OBJECTIVES: To assess the DIDO time of hospitals that transfer patients with STEMI to a PCI center and to assess its impact on total ischemia time and clinical outcomes in patients with STEMI. METHODS: We performed a retrospective study of 523 patients with STEMI transferred to a PCI center for primary PCI between January 1, 2013 and June 30, 2017. RESULTS: Median DIDO time was 82 min (interquartile range, 61-132 min). Only seven patients (1.3%) were transferred in ≤30 min. Patients with DIDO times over 60 min had significantly longer system delays (207.3 min vs. 112.7 min; p<0.001) and total ischemia time (344.2 min vs. 222 min; p<0.001) than patients transferred in ≤60 min. Observed in-hospital mortality was significantly higher among patients with DIDO times >60 min vs. ≤60 min (5.1% vs. 0%; p=0.006; adjusted odds ratio for in-hospital mortality, 1.27 [95% CI 1.062-1.432]). By the end of follow-up, patients belonging to the >60 min group had a higher mortality (p=0.016), and survival time was significantly shorter (p=0.011). CONCLUSION: A DIDO time ≤30 min was observed in only a small proportion of patients transferred for primary PCI. DIDO times of ≤60 min were associated with shorter delays in reperfusion, lower in-hospital mortality and longer survival times.