Determinants of hospital mortality after coronary artery bypass grafting

Objectives: To examine causes of death and to find predictors of hospital m ortality after elective coronary artery bypass graft (CABG) surgery. Design: Case-control study. Setting: Tertiary teaching hospital, Methods: We prospectively collected various preoperative. operative, and im mediate postoperative variables in a cohort of patients undergoing elective CABG surgery, Results: Of the 2,014 consecutive patients (mean [+/- SD] age of 61.3 +/- 6 .7 years old) undergoing elective CABG over a 2-year period, 27 patients (1 .3%) died during their hospitalization. The main causes of death (either is olated or in combination) were cardiogenic shock (n = 13), brain death or s troke (n = 7), septic shock (n = 4), ARDS (n = 2), and pulmonary embolism ( n = 1), A univariate statistical analysis revealed factors that significant ly correlate with outcome: patient age, preoperative left ventricular eject ion fraction, bypass time, aortic cross-clamp time, number of blood units t ransfused, number of inotropic agents administered in the operating room du ring the first postoperative day (POD), history of arterial hypertension, i ntra-aortic balloon pump usage, and perioperative development of shock. A l ogistic regression analysis showed that the combination of the number of in otropes and the number of blood units administered in the operating room du ring POD 1 n as the most important determinant of outcome, with an overall positive predictive value of 91.7%. Conclusions: We conclude that the analysis of simple variables enhances our ability to accurately predict hospital mortality in patients undergoing el ective CABG surgery. The number of inotropic agents and blood transfusions administered during the immediate postoperative period is the most importan t independent predictor of hospital mortality.