CLINICAL UTILITY OF TROPONIN-T LEVELS AND ECHOCARDIOGRAPHY IN THE EMERGENCY DEPARTMENT

We investigated the clinical utility of cardiac troponin T (TnT) and e chocardiography in the emergency department to predict subsequent in-h ospital diagnosis and adverse cardiac events. TnT is a cardiac-specifi c protein released during cell injury such as that following acute myo cardial infarction (MI). Unlike creatine kinase-MB isoenzymes, TnT is increased in a subset of patients with unstable angina, and these may be at higher risk for subsequent cardiac events. Echocardiography is a useful noninvasive imaging technique For the assessment of ischemic h eart disease in acute care settings because of its mobility and rapid results. Serial TnT determinations and echocardiographic images were p rospectively evaluated in 100 patients with chest discomfort and admit ted to the hospital. Serum was obtained for CKMB and TnT on presentati on to the emergency department and 4, 8, 16 and 24 hours later. TnT wa s considered increased when at values greater than 0.1 mu g/L. Echocar diograms were recorded on videotape in the emergency department and im ages reviewed in a blinded Fashion for wall-motion abnormalities. When available, current echocardiographic results were compared with previ ous results to determine whether a new wall-motion abnormality was pre sent. Of the 100 patients (57 men, 43 women), TnT was increased in 21 of 21 with acute MI and 15 of 41 with unstable angina. One of the 38 p atients with stable angina had an increased TnT value and died 5 month s later of a noncardiac cause. Ninety percent of patients who sustaine d acute MI had a TnT increase detected within 4 hours of presentation. Fifteen of 18 patients with acute MI and 9 of 37 patients with unstab le angina had a new wall-motion abnormality on echocardiography. The c ombination of TnT levels with echocardiography yielded a positive pred ictive value of 84% and a negative predictive value of 90% for adverse cardiac events in the follow-up population, which was more accurate t han either test analyzed separately TnT and echocardiography are usefu l tests in emergency department triage of unstable coronary syndromes. Both tests are predictive of discharge diagnosis and followup events. However, the combined utility of TnT levels and echocardiographic ima ging is a more powerful predictor of adverse cardiac events than isola ted results.