Implementation of High Sensitivity Cardiac Troponin T Measurement in the Emergency Department

BACKGROUND: We examined the diagnostic performance of high sensitivity cardiac troponin T (cTnThs) measurement and its ability to predict risk in unselected patients presenting to the emergency department with acute chest pain. METHODS: We conducted a retrospective analysis of 137 consecutive patients with chest pain (age range, 66 +/- 16 years; 64% male). A final diagnosis of acute myocardial infarction was made using the old (cTnT fourth-generation assay, >= 0.04 mu g/L) or the new cutpoint (cTnThs >= 0.014 mu g/L). RESULTS: The adjudicated final diagnosis of acute myocardial infarction significantly increased from 20 to 35 patients (a 75% increase) and troponin-positive nonvascular cardiac chest pain from 10 to 30 (a 200% increase) using cTnThs. The number of patients with unstable angina or troponin-negative nonvascular cardiac chest pain significantly decreased (P <.05). Diagnostic performance of cTnThs levels at admission was significantly higher compared to cTnT levels (area under the curve [AUC] 0.85 vs AUC 0.70; P <.05). cTnThs levels below the detection limit (<0.003 mu g/L) had a negative predictive value of 100% to exclude acute myocardial infarction. The event rate during 6 months of follow-up was low in patients with cTnThs levels <0.014 mu g/L, while patients with cTnT levels >= 0.04 mu g/L were at increased, and patients with cTnThs >= 0.014 mu g/L and cTnT <0.04 mu g/L at intermediate risk of death or recurrent myocardial infarction (P = .002). Risk was highest in chest pain patients with dynamic changes of cTnThs levels >30%. CONCLUSION: The introduction of cTnThs assay displays an excellent diagnostic performance for the workup of patients with chest pain at the time of their initial presentation. Even small increases of cTnThs indicate increased risk for death or myocardial infarction during follow-up. (C) 2010 Elsevier Inc. All rights reserved. The American Journal of Medicine (2010) 123, 1134-1142