Validation of a New Classification Method of Postoperative Complications in Patients Undergoing Coronary Artery Surgery

ObjectiveThe authors aimed to validate the European Multicenter Study on Coronary Artery Bypass Grafting (E-CABG) classification of postoperative complications in patients undergoing coronary artery bypass grafting (CABG).DesignRetrospective, observational study.SettingUniversity hospital.ParticipantsA total of 2,764 patients with severe coronary artery disease. Complete baseline, operative, and postoperative data were available for patients who underwent isolated CABG.InterventionsIsolated CABG.Measurements and Main ResultsThe E-CABG complication classification was used to stratify the severity and prognostic impact of adverse postoperative events. Primary outcome endpoints were 30-day, 90-day, and long-term all-cause mortality. The secondary outcome endpoints was the length of intensive care unit stay. Both the E-CABG complication grades and additive score were predictive of 30-day (area under the receiver operating characteristics curve 0.866, 95% confidence interval [CI] 0.829-0.903; and 0.876; 95% CI 0.844-0.908, respectively) and 90-day (area under the receiver operating characteristics curve 0.850, 95% CI 0.812-0.887; and 0.863, 95% CI 0.829-0.897, respectively) all-cause mortality. The complication grades were independent predictors of increased mortality at actuarial (log-rank: p<0.0001) and adjusted analysis (p<0.0001; grade 1: hazard ratio [HR] 1.757, 95% CI 1.111-2.778; grade 2: HR 2.704, 95% CI 1.664-4.394; grade 3: HR 5.081, 95% CI 3.148-8.201). When patients who died within 30 days were excluded from the analysis, this grading method still was associated with late mortality (p<0.0001). The grading method (p<0.0001) and the additive score (rho, 0.514; p<0.0001) were predictive of the length of intensive care unit stay.ConclusionsThe E-CABG postoperative complication classification seems to be a promising tool for stratifying the severity and prognostic impact of postoperative complications in patients undergoing cardiac surgery.