EVALUATION OF SERUM TROPONIN-T IN COMPARISON WITH CK-MB AS A DIAGNOSTIC FACTOR IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION

Abstract

The present study was designed to evaluate the value of cardiac troponin-T (cTn- T) to find out the best marker for diagnosis of acute myocardial infarction (AMI) in comparison to CK-MB measured by electrophoresis, mass concentration and catalytic activity. Also, assessment of the changes in the cardiac enzymes (T.CK, AST and LDH) and lipid profile (triacylglycerol, T.cholestero/ HDL-, LDL-and VLDL-cholesterol) were also carried out. The study included 39 patients diagnosed as AMI, 21 patients with unstable angina, 17 patients with stable angina, 6 patients with muscle diseases and 20 control subjects. AMI group subdivided into jive subgroups according to the time onset of chest pain. The diagnostic performance of cTn-T and the combined use of CK-MB mass and index were evaluated at different cut-off levels aiming at achievement of a high diagnostic efficiency with emphasis on the importance of early diagnosis of AMI within the first 6 hours of onset of symptoms. CTn-T was highly increased in all patients with AMI. It appeared in plasma slightly earlier than CK-MB hence aiding in the early diagnosis of the disease within the first hours after onset of symptoms . In stable angina, a higher relative increase of cTn-T was observed as compared to CK-MB mass and catalytic activity, this reflect some degree ofischaemic myocardial cell damage. The best cut-off level of cTn-T is 0.2 nglmL in order to overcome the problem of cross-reactivity with the skeletal muscle isoform and fetal isoforms which may be re­ expressed in response to skeletal muscle injury. For CK­ MB the best cut-off level is 7.6 nglmL aiming at achievement of the best diagnostic specificity.