Determination of the threshold of cardiac troponin I associated with an adverse postoperative outcome after cardiac surgery: a comparative study between coronary artery bypass graft, valve surgery, and combined cardiac surgery

Table 4 Analysis of the receiver operating curve (ROC) and determination of the thresholds of cardiac troponin I predicting the occurrence of postoperative severe cardiac event and/or death in patients undergoing coronary artery bypass graft surgery, valve surgery, or combined cardiac surgery, and in the global population

	Area under the ROC curve	Cardiac troponin I threshold (ng/ml)
Coronary artery bypass graft (n = 215)	0.777 (0.683–0.871)	7.8 (6.7–8.8)
Valve surgery (n = 215)	0.661 (0.559–0.763)	9.3 (8.0–14.0)*
Combined surgery (n = 216)	0.707 (0.634–0.780)	11.8 (11.5–14.8)*^†
Global population (n = 646)	0.740 (0.693–0.787)	10.4 (8.9–11.8)

Data expressed as the median (95% confidence interval). Bootstrap analysis (1,000 random sample of 75% of the population, see Materials and methods). *P < 0.05 versus coronary artery bypass graft; ^†P < 0.05 versus valve surgery. No statistical comparison was performed versus the global population values.

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