Cardiac troponin T in chest pain unit patients without ischemic electrocardiographic changes: Angiographic correlates and long-term clinical outcomes

OBJECTIVES We prospectively evaluated the relation between cardiac troponin T (cTnT) level, the presence and severity of coronary artery disease (CAD) and long-term prognosis in patients with chest pain but no ischemic electr ocardiographic (ECG)changes who had short-term observation. BACKGROUND Cardiac TnT is a powerful predictor of future myocardial infarct ion (MI) and death in patients with ECG evidence of an acute coronary syndr ome, However, for patients with chest pain with normal ECGs, it has not bee n determined whether cTnT elevation is predictive of CAD and a poor long-te rm prognosis. METHODS In 414 consecutive patients with no ischemic ECG changes who were t riaged to a chess pain unit, cTnT and creatine kinase, MB fraction (CK-MB) were evaluated greater than or equal to 10 h after symptom onset. Patients with adverse cardiac events, including death, MI, unstable angina and heart failure were followed for as long as one year. RESULTS A positive (>0.1 ng/ml) cTnT test was detected in 37 patients (8.9% ). Coronary artery disease was found in 90% of 30 cTnT-positive patients ve rsus 23% of 144 cTnT-negative patients who underwent angiography (p < 0.001 ), with multivessel disease in 63% versus 13% (p < 0.001). The cTnT-positiv e patients had a significantly (p < 0.05) higher percent diameter stenosis and a greater frequency of calcified, complex and occlusive lesions. Follow -up was available in 405 patients (98%). By one year 59 patients (14.6%) ha d adverse cardiac events. The cumulative adverse event rate was 32.4% in cT nT-positive patients versus 12.8% in cTnT-negative patients (p = 0.001). Af ter adjustment for baseline clinical characteristics, positive cTnT was a s tronger predictor of events (chi-square = 23.56, p = 0.0003) than positive CK-MB (>5 ng/ml) (chi-square = 21.08, p = 0.0008). In a model including bot h biochemical markers, CK-MS added no predictive information as compared wi th cTnT alone (chi-square = 23.57, p = 0.0006). CONCLUSIONS In a group of patients with chest pain anticipated to have a lo w prevalence of CAD and a good prognosis, cTnT identifies a subgroup with a high prevalence of extensive and complex CAD and increased risk for long-t erm adverse outcomes. (J Am Coll Cardiol 2000;35:1827-34) (C) 2000 by the A merican College of Cardiology.