Effects of decreased preoperative endotoxin core antibody levels on long-term mortality after coronary artery bypass graft surgery

Hypothesis: Decreased preoperative levels of antiendotoxin core antibody (EndoCAb) in patients undergoing cardiac surgery with cardiopulmonary bypass are associated with increased long-term mortality. Design: Observational study. Setting: Academic medical center. Patients: A total of 474 patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass. Interventions: Preoperative serum IgM EndoCAb levels were determined, and established preoperative risk factors were assessed. Patients were assigned a risk score using a validated method. Main Outcome Measures: The primary end point was mortality. Statistical analysis used the Cox proportional hazards regression model with log EndoCAb as the predictor of interest and Parsonnet additive risk score as a covariate. Kaplan-Meier survival curves were generated to visually compare groups with high vs low EndoCAb levels. Results: Forty-six deaths occurred in 5 years. Annual follow-up rates during the 5 years were 100%, 94%, 93%, 98%, and 98% for the 1-, 2-, 3-, 4-, and 5-year periods, respectively. Parsonnet additive risk score (hazard ratio, 1.07;95% confidence interval [CI], 1.04-1.11; P<.001) and log EndoCAb (hazard ratio, 0.73; 95% CI, 0.53-0.99; P=.04) were independent predictors of long-term mortality in the final model. Kaplan-Meier analysis revealed that the preoperative EndoCAb level was significantly associated with mortality up to 5 years (P=.01 by log-rank test) Conclusion: Lower preoperative serum EndoCAb level is a significant predictor of long-term mortality independent of other known risk factors.