Troponin T as a Marker of Infarction during Coronary Bypass Surgery

To evaluate serum troponin T as a marker of perioperative myocardial infarction, 50 patients undergoing coronary artery bypass grafting were divided into 2 groups. Group A (14 patients) had serum creatine kinase MB-isoenzyme levels above 100 U·L −1 and electrocardiographic changes indicative of infarction. Group B (36 patients) had creatine kinase MB levels below 100 U·L −1 and no electrocardiographic changes. Blood samples were obtained preoperatively, 6 hours after aortic declamping, and on postoperative day 1, 2, and 3. Following surgery, all patients had increased levels of troponin T and creatine kinase MB. Troponin T was significantly higher in group A compared to group B at 6 hours, day 1, and day 2 postoperatively. Creatine kinase MB levels were significantly higher in group A compared to group B at 6 hours and day 1 postoperatively. The increased levels of troponin T in patients without myocardial infarction suggest that some operative myocardial damage occurred. Patients with perioperative myocardial infarction had significantly higher levels of troponin T up to postoperative day 2, whereas creatine kinase MB levels were almost normal by day 2. This suggests that troponin T may be used up to 2 days postoperatively for detection of myocardial infarction.