MYOCARDIAL RELEASE OF TROPONIN-T AFTER CORONARY-BYPASS SURGERY

The temporal changes in cardiac S-troponin T, S-creatine kinase-MB(S-C K-MB)(mass) and S-myoglobin were studied for 5 days after coronary byp ass grafting in 70 patients. Perioperative infarction occurred in ten patients (2 Q wave, 8 non-Q wave). All three markers showed significan t increase even in patients without signs of perioperative infarction. Within 8-12 hours their levels rose significantly (p < 0.001) more in the infarction than in the non-infarction cases. Troponin T and CK-MB (mass) both showed early (<8-12 h) peaks in patients with perioperativ e infarction. CK-MB(mass) returned to near normal levels within 48-72 hours, whereas troponin T remained markedly increased throughout the o bservation. Myoglobin concentrations varied widely among the infarctio n cases. In the non-infarction group, troponin T and CK-MB(mass) (but not myoglobin) were related to the aortic cross-clamp time. Troponin T (but not CK-MB(mass)) remained elevated throughout the study period i n patients with longer cross-clamp times. These findings may indicate continuous release from damaged myocardium in cases of perioperative i nfarction. Troponin T and CK-MB(mass) can serve as markers of perioper ative infarction and troponin T may also be useful as a marker in stud ies on myocardial protection.