Factors associated with poor clinical outcomes of ST-elevation myocardial infarction in patients with door-to-balloon time <90 minutes

Background Recent guidelines for ST-elevation myocardial infarction (STEMI) recommended the door-to-balloon time (DTBT) <90 minutes. However, some patients could have poor clinical outcomes in spite of DTBT <90 minutes, which suggest the importance of therapeutic targets except DTBT. The purpose of this study was to find factors associated with poor clinical outcomes in STEMI patients with DTBT Methods This retrospective study included 383 STEMI patients with DTBT <90 minutes. The primary endpoint was the major adverse cardiac events (MACE) defined as the composite of all-cause death, acute myocardial infarction, and acute heart failure requiring hospitalization. Result The median follow-up duration was 281 days, and the cumulative incidence of MACE was 16.2%. In the multivariate Cox hazard model, low body mass index (< 20 kg/m(2)) (vs. >20 kg/m(2): HR 2.80, 95% CI 1.39-5.64, p = 0.004), history of previous myocardial infarction (HR 2.39, 95% CI 1.06-5.37, p = 0.04), and Killip class 3 or 4 (vs. Killip class 1 or 2: HR 2.39, 95% CI 1.30-4.40, p = 0.005) were significantly associated with MACE. In another multivariate Cox hazard model, flow worsening during percutaneous coronary intervention (PCI) (HR 3.24, 95% CI 1.79-5.86, p<0.001) and use of mechanical support (HR 3.15, 95% CI 1.71-5.79, p<0.001) were significantly associated with MACE, whereas radial approach (HR 0.54, 95% CI 0.32-0.92, p = 0.02) was inversely associated with MACE. Conclusion Low body mass index, Killip class 3/4, history of previous myocardial infarction, use of mechanical support, and flow worsening were significantly associated with MACE, whereas radial-access was inversely associated with MACE. It is important to avoid flow worsening during primary PCI even when appropriate DTBT was achieved.