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.