High-sensitivity cardiac troponin T for earlier diagnosis of acute myocardial infarction in patients with initially negative troponin T test-Comparison between cardiac markers

Background and purpose: An early diagnosis is essential for therapeutic decision and risk stratification in patients with suspected acute myocardial infarction (AMI). We analyzed and compared the diagnostic value of high-sensitivity troponin T (hs-TnT) and other cardiae markers in patients with an initially negative troponin T test at presentation. Methods and subjects: The present study was a prospective, multicenter study including five participating emergency cardiovascular tertiary centers in Japan. From November 2009 through January 2011, patients with suspected AMI at the emergency room with an initial troponinT(c-TnT) test <100 ng/L were enrolled. Results: A total of 85 patients were prospectively assigned from five participating emergency cardiovascular tertiary centers in Japan. The median time from the onset of chest pain to the TO sampling was 165 min fIQR 120-1801. The final diagnoses according to the recent universal definition and other standard cut-off values were AMI in 47, unstable angina in 12, and non AMI in 38 patients. The overall ROC-AUC value of hs-TnT, c-TnT, creatine kinase MB, and heart-type fatty acid-binding protein were 0.810, 0.716, 0.782, and 0.880, respectively. The diagnostic sensitivity and negative predictive value of hs-TnT were both 100% for the patients admitted more than 120 min from the onset, however the specificity was limited for the whole time-windows (71%). The absolute value change of the hs-TnT from TO to 13 sampling 3 h later improved the ROC-AUC up to 0.972 and the specificity was 92% at 22 ng/L (ROC-optimized cut-off) and 100% at 105 ng/L (rule-in cut-off). Conclusions: The hs-TnT displayed 100% sensitivity and negative predictive value for the patients admitted more than 120 min from the onset, however the specificity was limited. The absolute change from TO to T3 (22 ng/L) improved the total diagnostic performance. (C) 2013 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.