title: ST-elevation myocardial infarction mortality in a major academic center "on-" versus "off-" hours.
abstract: BACKGROUND
  A higher mortality rate for weekend myocardial infarction (MI) admissions has been reported and attributed to the lower availability of primary percutaneous coronary intervention (PCI) during off-hours. However, the data are conflicting and, furthermore, inapplicable to hospitals where primary PCI is invariably performed.
  
  
  METHODS
  This study was conducted in a tertiary hospital where primary PCI is routinely performed in all patients with ST-elevation myocardial infarction (STEMI). Patients admitted during on-hours (Monday through Friday 7 am-7 pm) where compared to off-hours patients (including weekends). The primary endpoint of in-hospital mortality, cardiogenic shock and recurrent MI was examined. A second analysis that excluded STEMI transfers, in-hospital mortality and reperfusion times was examined.
  
  
  RESULTS
  Between 2003 and 2007, 747 STEMI patients (46% on-hours vs. 56% off-hours) underwent primary PCI. Demographic characteristics were similar between on- and off-hours groups. However, off-hours STEMI admissions had significantly greater in-hospital mortality rates (8% vs. 3.7%; p = 0.01) and higher rates of cardiogenic shock (37% vs. 24%; p = 0.0001). Admission arrival time was an independent predictor of in-hospital mortality (hazard ratio [HR] 3.98, 95% confidence interval [CI] 1.10-14.38; p = 0.035). Longer door-to-balloon times (DTB) were observed during off-hours (134 vs. 109 minutes; p < 0.0001), even after excluding the transfer population (63 vs. 89 minutes; p < 0.0001).
  
  
  CONCLUSIONS
  Higher rates of in-hospital mortality and cardiogenic shock may be expected in STEMI patients admitted during off-hours, even when primary PCI is performed. Longer DTB times during off-hours may partially explain our findings. Strategies to optimize reperfusion time during off-hours, including perhaps a 24/7 in-house "STEMI team" may be necessary.
authors.affiliation: Massachusetts General Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Roberto J
authors.initials: RJ
authors.lastname: Cubeddu
authors.forename: Ignacio
authors.initials: I
authors.lastname: Cruz-Gonzalez
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Kiernan
authors.forename: Quynh A
authors.initials: QA
authors.lastname: Truong
authors.forename: Kenneth
authors.initials: K
authors.lastname: Rosenfield
authors.forename: Robert C
authors.initials: RC
authors.lastname: Leinbach
authors.forename: Mary E
authors.initials: ME
authors.lastname: Cadigan
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Pomerantsev
authors.forename: Igor F
authors.initials: IF
authors.lastname: Palacios
mesh_terms: D000046:Academic Medical Centers / Q000706:statistics & numerical data*; D039602:After-Hours Care / Q000706:statistics & numerical data*; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D004562:Electrocardiography; D005260:Female; D006297:Health Services Accessibility / Q000706:statistics & numerical data; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality* / Q000628:therapy*; D012008:Recurrence; D012189:Retrospective Studies; D012770:Shock, Cardiogenic; D013997:Time Factors