Troponin T is an Early Marker of Reperfusion After Acute Myocardial Infarction

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Abstract

Objectives

To assess troponin T (cTnT) evolution during the first 24 hours in acute myocardial infarction (AMI) and to correlate cTnT with CK on admission, time elapsed from symptom onset and non-invasive reperfusion criteria.

Material and method

Sixty patients (pts) with AMI, admitted to CCU with less than6 hours from symptom onset, were included. Reperfusion strategies (RS) were applied in 49 pts: SK or t-PA in 33 pts, and primary PTCA16 pts. cTnT, CK and CK-MB levels were assessed on admission, 2, 6, 12 and 24 hours. cTnT ≥ 0.1 ng/ml was considered abnormal. ST segment elevation summatory was evaluated on admission and after two hours, and a >_ 50% fall at two hours was considered as positive reperfusion criteria (REP+).ResultsOn admission, cTnT level was 2.27 ± 5.8 ng/ml, at2 hrs 16 ± 23.4 ng/ml, at 6 hrs 18 ± 26 ng/ml, at 12hrs 16.8 ± 20 ng/ml, and at 24 hrs 13.2 ± 17.4 ng/ml.Based on > 0.1 ng/ml cTnT value, 31 pts with normal CK-level at entrance, had elevated cTnT. Only 4 pts out of 22 with CK elevated levels at admission had cTnT levels <_ 0.1 ng/ml(p< 0.01). Early cTnT levels had no relation with time from symptom onset. A REP(+) ST criteria was con-firmed in 39 pts, and absence in 10 pts (REP-).Evolutive levels of cTnT 2, 6 and 12 hrs were different in pts with REP+ vs. REP(-):17.9, 25.6 and 20.8 (REP+) vs. 12.4, 12.8 and 16.3 respectively(REP-), (p= 0.02, 0.006 and 0.02).Conclusions1) In patients with AMI with less than 6 hours of evolution, cTnT was an earlier sensitive marker of myocardial necrosis compared to CK or CK-MB.2) There was not relation between baseline cTnT levels and time from symptom onset. 3) cTnT levels evolution during the first 12 hours were strongly related to non-invasive reperfusion criteria as ST segment resolution, and should be explored prospectively as a non-invasive reperfusion marker with clinical usefulness.