Sensitivity, specificity and predictive value of the echocardiography and troponin-T test combination in patients with non-ST elevation acute coronary syndromes.

INTRODUCTION: Patients with a negative troponin (TnT) result showed 1.4% mortality during a mean follow-up of 9-10 weeks. Mortality was greater in patients with an evidence of ischemic ECG changes and a negative TnT test (1.6-4.4%). Few studies have examined the efficacy of echocardiography (2DE) in patients with chest pain. The purpose of the present study was to determine the clinical utility, sensitivity and specificity of the combination of TnT levels and 2DE in patients presenting with chest pain, ST-depression, T-wave negative and no diagnostic ECG.
METHODS: 280 consecutive patients with chest pain and presence of ST depression, T-wave inversion, and non-diagnostic ECG, acceptable 2DE window, evidence or no evidence of alterations of the segmentary motion, and evidence and no evidence of injury, as assessed by TnT and normal value of CK-CK MB, were enrolled. 2DE, blood CK, and TnT levels were controlled at entry and subsequent samples were obtained every 4 h for the first 12 h and then every 12 h. All patients performed angiography within 12-72 from admission. PTCA or CABG were performed according to angiographic findings and left ventricular function.
RESULTS: The 280 patients (98 F/M 182), mean age 59.7+/-11.9 years, who met the entry criteria, were divided as follows: group 1: ST-segment depression (192 patients); group 2: T-wave inversion (36 patients); and group 3: non-diagnostic ECG (52 patients). The combination of positive TnT and wall motion alterations showed a higher sensitivity, specificity and predictive values in comparison with alone TnT or 2DE. Patients, with the concordance between TnT and 2DE, were at higher risk. Patients with negative combination in all groups (94), showed a low incidence of coronary stenosis (10.6%), as well as negative 2DE alone (102 patients) (12.7%), while patients with negative TnT (128) showed higher incidence of coronary stenosis (39%), p < 0.0001.
CONCLUSION: Our results suggest that the combination of negative TnT test and negative 2DE in patients presenting to EDs with chest pain either with ECG changes or without ECG changes is a useful tool to identify those who can be discharged safely. We think that our data are important because by the combination we can identify the high risk (when positive) patients, reduce incidence of the false negative, but mostly it allows us to identify true negative patients to discharge safely.