Availability of Cardiac Troponin T as a Marker for Detecting Perioperative Myocardial Damage in Patients with Open Heart Surgery

Kim, Tae Ye; Jung, Tae Eun; Lee, Dong Hyup; Lee, Jung Chul; Han, Sung Sae

Abstract

It is well known that troponin T (below TnT) is present in the myocardial cells and released during myocardial damage, so it`s very specific enzyme to myocardium. Availability of cardiac specific TnT in assessing perioperatively myocardial damage was evaluated from 34 open heart surgery patients. They consisted of 11 ischemic heart, 13 acquired valvular heart and 10 congenital heart cases. Patients were divided into two groups, group A (patients with myocardial damage) and group B (patients without myocardial damage), according to the symptom of chest pain suspecting angina and the ECG findings of ST segment and T wave changes which show myocardial ischemia and injury. Serum TnT levels were measured by enzyme immunoassay method preoperatively, immediately postoperatively, postoperative day 1, day 2, day 3, and day 7. We observed and analyzed the changes of serum TnT levels in two groups and compared the serum TnT levels with CK-MB levels measured at the same time. In group A, serum TnT levels showed 1.37+/-0.26microgram/L, 3.16+/-0.66microgram/L, 2.39+/-0.74microgram/L, 2.49+/-0.76microgram/L, and 1.23+/-0.60microgram/L, immediate postoperatively, postoperatively day1, day2, day3, and day7, respectively. It was observed there were significant differences compared with those of group B (0.38+/-0.04microgram/L, 0.34+/-0.05microgram/L, 0.25+/-0.03microgram/L, 0.24+/-0.04microgram/L, and 0.11+/-0.03microgram/L) during identical periods (p<0.01). Serum CK-MB level in group A significantly elevated to 145.04+/-35.08 IU/L on the postoperative day 1 compared to group B (31.28+/-5.87 IU/L, p<0.05), However, it stiffly decreased from day 2 and returned to preoperative level at day 3. When serum TnT level more than 1.0microgram/L is thought to reflect myocardial damage, serum TnT had 100% of sensitivity and 87% of specificity in diagnosing the postoperative myocardial damage (p<0.01). I conclusion, serum TnT levels increased significantly at very early stage of myocardial damage and persisted much longer period than CK-MB. This suggests that serum TnT has more advantage and availability in assessing the perioperatively myocardial damage than any other tests.