Relationship of preoperative antiendotoxin core antibodies and adverse outcomes following cardiac surgery

Measuring the level of IgM antibodies against endotoxin may predict which patients will develop complications from heart surgery. Endotoxin is a component of bacteria and may initiate an inflammatory response in surgical patients. Researchers measured the levels of IgM and IgG antibodies to endotoxin (EndoCAb) in 301 patients before they had heart surgery. Following surgery, 11.3% of the patients developed a complication. Those with low IgM EndoCAb levels were more likely to develop a complication even after adjusting for other risk factors.
Objective.--To test the hypothesis that low serum antiendotoxin core antibody (EndoCAb) level is an independent predictor of adverse outcome following cardiac surgery. Design,-- Prospective, blinded, cohort study. Setting.--Tertiary care medical center. Subjects.--A total of 301 patients undergoing coronary artery bypass graff surgery and/or valvular heart surgery. Design.--Preoperative serum was assayed for IgM EndoCAb, IgG EndoCAb, total IgM, and total IgG levels. Known preoperative risk factors were assessed, and patients were assigned a risk score using a validated method. Main Outcome Measure--A major complication, defined as either in-hospital death or postoperative length of stay greater than 10 days. Results.---Overall, a major complication occurred in 34 patients (11.3%). Lower IgM EndoCAb level independently predicted (P--.002) increased risk of major complication over and above the effects of preoperative risk score (P=.02), total IgG level (P--.07), and all other known perioperative risk factors. In contrast, IgG EndoCAb and total IgM concentrations did not predict outcome. No association existed between risk score and level of IgM EndoCAb. Conclusion.--There is marked preoperative variability in humoral immunity against endotoxin core, which is not accounted for by differences in known preoperative risk factors. In this study, low levels of IgMEndoCAb were an important independent predictor of adverse postoperative outcome, which supports the theory that endotoxemia is a cause of postoperative morbidity. JAMA. 1997;277:646-650