DIAGNOSTIC PERFORMANCE AND PROGNOSTIC VALUE OF SERUM TROPONIN-T IN SUSPECTED ACUTE MYOCARDIAL-INFARCTION

Cardiac troponin T (TnT) is a new serological marker for use as a diag nostic tool for myocardial damage. A blinded prospective multicentre s tudy representing 298 patients suspected of having acute myocardial in farction (AMI), and admitted to the coronary care units of six Scandin avian Hospitals was undertaken to assess the diagnostic performance an d prognostic efficacy of a new cardiospecific TnT immunoassay. We used a discriminator TnT value of 0.20 mug l-1. One hundred and fifty five patients (52%) had definite AMI, based on WHO criteria (all had peak S-TnT values of greater-than-or-equal-to 0.20 mug l-1); 127 patients ( 43%) had ischaemic heart disease (IHD) without AMI; and 16 patients (5 %) had non-IHD (all had peak S-TnT values of < 0.20 mug l-1). The 127 IHD-patients without definite AMI could be subdivided into a group of 44 patients with S-TnT peak values of greater-than-or-equal-to 0.20 mu g l-1, and a group of 83 patients with TnT below this level. An equal identification of these patients among the centres was seen (mean +/- SD 35 +/- 13%; range 20-55%). A follow-up study was able to define the clinical significance of these findings. The cumulative 6 months prob ability of suffering cardiac death or AMI was significantly higher in the subgroup with increased TnT values (14% (6/44)) as compared to the other subgroup (4% (3/83)) (Log-rank test, p = 0.025). The probabilit y of cardiac events was 15% for the patients with definite AMI. We con clude that increased troponin T in serum can detect a subgroup of IHD- patients in whom AMI has been ruled out, but who still have a prognosi s as serious as patients with definite AMI.