[Clinical significance of serum troponin T following coronary artery bypass surgery].

We evaluated the clinical significance of serum cardiac troponin T(TnT) following coronary artery bypass surgery (CABG) as an indicator of cardiac damage during the operation. We studied 21 patients who underwent CABG and 8 patients who underwent open thoracotomy for lung disease. In the CABG patients, serum TnT levels showed roughly biphasic release kinetics, with a peak less than 10h postoperatively and a second peak on or about the fourth day. The serum TnT levels at 0 and 10h postoperatively were 8.58 +/- 1.07 (mean +/- SE) and 9.19 +/- 1.35ng/ml, respectively, levels were 30-40 times higher than the cut-off value of 0.25ng/ml. On the fourth day after CABG, serum TnT in the 3 graft groups (7.21 +/- 2.56ng/ml) was significantly higher than in the 1 or 2 graft groups (2.57 +/- 0.05 and 2.53 +/- 0.46ng/ml, respectively). The peak serum TnT level of the patients with perioperative myocardial infarction was 34.6 +/- 5.29ng/ml, which was significantly higher than in the patients without specific evidence of perioperative infarction. On the other hand, in the patients undergoing thoracic surgery for lung disease, serum TnT showed no postoperative increase. In conclusion, serum TnT appears to be a specific marker of cardiac damage after CABG, and may be useful for the diagnosis of perioperative myocardial infarction.