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.