title: Decreasing significance of left ventricular dysfunction and reoperative surgery in predicting coronary artery bypass grafting-associated mortality: a twelve-year study.
abstract: OBJECTIVE
  Patients undergoing coronary artery bypass grafting are older and have greater comorbidity than those operated on previously. We evaluated the changes in the predictors of in-hospital mortality among patients undergoing coronary artery bypass grafting during the last 12 years.
  
  
  METHODS
  Data on demographic characteristics, preoperative risk factors, operative variables, and hospital outcomes were collected prospectively for all patients undergoing isolated coronary artery bypass grafting at a single institution from January 1, 1990, to December 31, 2001. To examine the effect of time on patient risk profiles and outcomes, we divided patients into three groups according to year of operation (1990-1993 n = 5171, 1994-1997 n = 5977, 1998-2001 n = 6893).
  
  
  RESULTS
  In-hospital mortality declined from 2.4% (1990-1993) to 1.2% (1998-2001, P <.0001). Left ventricular dysfunction, increasing age, female gender, hypertension, diabetes, cardiogenic shock, congestive heart failure, peripheral vascular disease, reoperative coronary artery bypass grafting, left main disease, and urgent surgery independently predicted in-hospital mortality in the entire cohort of 18,041 patients. Severe left ventricular dysfunction was the most significant predictor of in-hospital mortality in the 12-year cohort, but it had a declining influence with time (1990-1993 odds ratio 7.1, 1994-1997 odds ratio 5.1, 1998-2001 not statistically significant) because of improving outcomes. Reoperative coronary artery bypass grafting similarly decreased in significance as a predictor of mortality. Emergency coronary artery bypass grafting was performed less frequently in recent years, but the requirement for emergency surgery carried an increasing odds ratio for mortality.
  
  
  CONCLUSIONS
  Despite increasing patient age and comorbidity, improvements in perioperative management have reduced the significance of severe left ventricular dysfunction and reoperative coronary artery bypass grafting but not emergency surgery as predictors of in-hospital mortality.
authors.affiliation: Division of Cardiocascular Surgery, Yoronto General Hospital, University Health Network, Department of Surgery, and the Heart/Stroke Foundation/Richard Lewar Centre for Excellence, University of Toronto, Ontario, Canada.
authors.forename: Piroze M
authors.initials: PM
authors.lastname: Davierwala
authors.forename: Manjula
authors.initials: M
authors.lastname: Maganti
authors.forename: Terrence M
authors.initials: TM
authors.lastname: Yau
mesh_terms: D000367:Age Factors; D000368:Aged; D002423:Cause of Death; D016001:Confidence Intervals; D001026:Coronary Artery Bypass / Q000379:methods / Q000401:mortality*; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000401:mortality* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011336:Probability; D011446:Prospective Studies; D012042:Registries; D012086:Reoperation; D012307:Risk Factors; D012720:Severity of Illness Index; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*