Prognostic efficacy of troponin T measurement in angina pectoris

This study was designed to evaluate the efficacy of the newly developed Troponin T (TNT) enzyme immunoassay for predicting the prognosis of patients with angina pectoris. TNT, creatine kinase (CK) and MB isoenzyme of creatine kinase (CK-MB) were monitored in 134 patients with angina pectoris. There was no abnormality with any of these tests in 40 patients with stable angina pectoris and 30 patients with unstable angina pectoris of Class 1 and 2 according to Braunwald's criteria. None of them developed acute myocardial infarction or other cardiac events. Elevation of TNT concentration with normal level of CK and CK-MB was found in 34 of the 64 cases of unstable angina pectoris of Class 3. Among the 34 patients, 11 had acute myocardial infarction within 10 days during hospitalization. In contrast, only one of the patients with unstable angina pectoris of Class 3 with normal value of TNT developed acute myocardial infarction. As the incidence of angina pectoris is quite high clinically but only a small number of patients developed myocardial infarction, it is necessary to have a new assay of high sensitivity and high negative predictive value. TNT determination could meet these requirements as it had high sensitivity (92%) and high negative predictive value (98%) for the prognosis of unstable angina pectoris. If there is no rise of circulating TNT level, a favorable outcome can be expected with a high degree of probability. Determination of serum TNT level would be adopted as a routine procedure for evaluating the prognosis of angina pectoris and it is superior to other enzyme tests such as CK and CK-MB.