Abstract 6275: Increased Mortality after Primary Percutaneous Coronary Intervention for Acute ST Segment Elevation Myocardial Infarction During Off-Hours

Abstract

Background: Higher mortality has been reported in patients admitted with acute myocardial infarction during off-hours, and has been related to a lower use of primary percutaneous coronary intervention (PCI). Methods: We thus conducted a study, where primary PCI is routinely performed in all patients with ST elevation myocardial infarction (STEMI) regardless of the day and time of admission. Patients admitted during on-hours (Monday through Friday 7am–6pm) where compared to off-hours (including weekends). The outcome of in-hospital mortality, cardiogenic shock and recurrent myocardial infarction was explored. The different components of door-to-balloon (DTB) time were examined and compared between both groups. Results: Between 2003 and 2007, 747 STEMI patients (46% on-hours vs. 56% off-hours) underwent primary PCI. Patient baseline demographic characteristics were similar during on-vs. off-hours. Admissions during off-hours were associated with longer DTB times (134 vs. 109 minutes, p<0.0001). Furthermore, patients admitted during off-hours had significantly greater in-hospital mortality (8% vs. 3.7%, p=0.01), and higher rates of cardiogenic shock (37% vs. 24%, p=0.0001). Multivariate analysis identified admission arrival time as an independent predictor of in-hospital mortality (HR 3.98; 95% CI 1.10 –14.38; p=0.035). Longer DTB times were attributed to the increased “engagement time” during off-hours (27 vs. 47 minutes, p<0.00001). Conclusion: 1) This study is the first to show that even when treated equally with primary PCI, off-hours STEMI admissions have higher mortality than on-hours. Longer DTB time during off-hours likely explain our findings. Strategies to optimize hospital protocols, reperfusion therapies, and perhaps a dedicated in-house “STEMI team” during off-hours need to be revised.