Cardiac troponin I concentrations, but not electrocardiographic results, predict an extended hospital stay after coronary artery bypass graft surgery

Abstract

Background: Cardiac damage in coronary artery graft (CABG) surgery is an important contributor to postoperative cardiac dysfunction and delayed hospital discharge. Currently, no simple method exists for its quantification. Methods: In a prospective study of 300 patients having routine CABG surgery, we compared cardiac troponin I (cTnI) concentrations at 6 and 24 h after surgery with electrocardiographic (ECG) results as predictors of an extended postoperative stay in the intensive care unit (ICU) and in the hospital. We stratified outcome variables by tertiles of cTnI concentration and studied the significance of differences between outcome variables across tertiles. Results: Multivariate analysis showed that 24-h cTnI is a significant predictor of increased postoperative ICU stay (P = 0.012) and postoperative hospital stay (P = 0.024). For 6-h cTnI, corresponding significance values were P = 0.29 and 0.9. ECG was of no value (P = 0.39 and 0.47). Differences in 24-h cTnI were highly significant, particularly for lowest vs highest tertiles, and allowed stratification of risk into "low" (<10 μg/L), "equivocal" (10-20 μg/L), and "high" (>20 μg/L). Conclusions: Use of a single 24-h cTnI value to quantify perioperative myocardial damage identifies patients who are at greater risk of extended ICU and hospital stays. This strategy could assist in allocation of patients to different management streams after CABG surgery. © 2005 American Association for Clinical Chemistry.