Effects of Door-In to Door-Out Time on Mortality Among ST-Segment Elevation Myocardial Infarction Patients Transferred for Primary Percutaneous Coronary Intervention　― Systematic Review and Meta-Analysis ―

Background: Primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) is now widely accepted. Recent guidelines have focused on total ischemic time, because shorter total ischemic time is associated with a more favorable prognosis. The door-in to door-out (DIDO) time, defined as time from arrival at a non-PCI-capable hospital to leaving for a PCI-capable hospital, may affect STEMI patient prognosis. However, a relevant meta-analysis is lacking. Methods and Results: We searched PubMed for clinical studies comparing short-term (30-day and in-hospital) mortality rates of STEMI patients undergoing primary PCI with DIDO times of ≤30 vs. >30 min. Two investigators independently screened the search results and extracted the data. Random effects estimators with weights calculated by the inverse variance method were used to determine pooled risk ratios. The search retrieved 1,260 studies; of these, 2 retrospective cohort studies (15,596 patients) were analyzed. In the DIDO time ≤30 and >30 min groups, the primary endpoint (i.e., in-hospital or 30-day mortality) occurred for 51 of 1,794 (2.8%) and 831 of 13,802 (6.0%) patients, respectively. The incidence of the primary endpoint was significantly lower in the DIDO time ≤30 min group (odds ratio 0.45; 95% confidence interval 0.34–0.60). Conclusions: Our findings suggest that a DIDO time ≤30 min is associated with a lower short-term mortality rate. However, further larger systematic reviews and meta-analyses are needed to validate our findings.