title: Academic season does not influence cardiac surgical outcomes at US Academic Medical Centers.
abstract: BACKGROUND
  Previous studies have demonstrated the influence of academic season on outcomes in select surgical populations. However, the influence of academic season has not been evaluated nationwide in cardiac surgery. We hypothesized that cardiac surgical outcomes were not significantly influenced by time of year at both cardiothoracic teaching hospitals and non-cardiothoracic teaching hospitals nationwide.
  
  
  METHODS
  From 2003 to 2007, a weighted 1,614,394 cardiac operations were evaluated using the Nationwide Inpatient Sample database. Patients undergoing cardiac operations at cardiothoracic teaching and non-cardiothoracic teaching hospitals were identified using the Association of American Medical College's Graduate Medical Education Tracking System. Hierarchic multivariable logistic regression analyses were used to estimate the effect of academic quarter on risk-adjusted outcomes.
  
  
  RESULTS
  Mean patient age was 65.9 ± 10.9 years. Women accounted for 32.8% of patients. Isolated coronary artery bypass grafting was the most common operation performed (64.7%), followed by isolated valve replacement (19.3%). The overall incidence of operative mortality and composite postoperative complication rate were 2.9% and 27.9%, respectively. After accounting for potentially confounding risk factors, timing of operation by academic quarter did not independently increase risk-adjusted mortality (p = 0.12) or morbidity (p = 0.24) at academic medical centers.
  
  
  CONCLUSIONS
  Risk-adjusted mortality and morbidity for cardiac operations were not associated with time of year in the US at teaching and nonteaching hospitals. Patients should be reassured of the safety of performance of cardiac operations at academic medical centers throughout a given academic year.
authors.affiliation: Department of Surgery, University of Virginia Health System, Charlottesville, VA, USA.
authors.forename: Damien J
authors.initials: DJ
authors.lastname: Lapar
authors.forename: Castigliano M
authors.initials: CM
authors.lastname: Bhamidipati
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Mery
authors.forename: George J
authors.initials: GJ
authors.lastname: Stukenborg
authors.forename: Christine L
authors.initials: CL
authors.lastname: Lau
authors.forename: Irving L
authors.initials: IL
authors.lastname: Kron
authors.forename: Gorav
authors.initials: G
authors.lastname: Ailawadi
mesh_terms: D000046:Academic Medical Centers / Q000592:standards* / Q000706:statistics & numerical data*; D000368:Aged; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000401:mortality*; D005260:Female; D006784:Hospitals, Teaching / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D009026:Mortality / Q000639:trends; D017063:Outcome Assessment, Health Care / Q000592:standards / Q000639:trends; D012307:Risk Factors; D012621:Seasons; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology