Diagnostic Accuracy of High-Sensitivity Cardiac Troponin T at Presentation Combined With History and ECG for Ruling Out Major Adverse Cardiac Events.

STUDY OBJECTIVE: We evaluate the diagnostic accuracy of a high-sensitivity cardiac troponin T (hs-cTnT) level less than 5 ng/L or less than or equal to 14 ng/L at emergency department (ED) presentation, combined with the emergency physician's assessment of history and ECG, for ruling out major adverse cardiac events within 30 days.

METHODS: This prospective observational study enrolled consecutive ED chest pain patients. Emergency physicians' assessments of patient history and ECG were collected. The primary outcome was 30-day major adverse cardiac events, defined as acute myocardial infarction, unstable angina, cardiogenic shock, ventricular arrhythmia, atrioventricular block, cardiac arrest, or death of cardiac or unknown cause.

RESULTS: A total of 1,138 patients were included in the final analysis. The combination of hs-cTnT less than 5 ng/L, a nonischemic ECG result, and a nonhigh risk history was present for 29.2% of all patients and had a sensitivity of 99.2% (95% confidence interval [CI] 95.6% to 100%), negative predictive value (NPV) of 99.7% (95% CI 98.3% to 100%), and a negative likelihood ratio of 0.02 (95% CI 0 to 0.17) for 30-day major adverse cardiac events. The same combination with hs-cTnT less than or equal to 14 ng/L was present in 66.7% of the patients and had a sensitivity of 92% (95% CI 85.8% to 96.1%), NPV of 98.7% (95% CI 97.6% to 99.4%), and negative likelihood ratio of 0.11 (95% CI 0.06 to 0.20).

CONCLUSION: A single hs-cTnT result of less than 5 ng/L at ED presentation when combined with a nonischemic ECG result and a nonhigh risk history identified 29% of chest pain patients at a very low risk of 30-day major adverse cardiac events. A similar strategy with hs-cTnT less than or equal to 14 ng/L was associated with a higher miss rate.