Diagnostic performance of rising, falling, or rising and falling kinetic changes of high-sensitivity cardiac troponin T in an unselected emergency department population.

BACKGROUND: Current ESC guidelines for the diagnosis of myocardial infarction consider a rise and/or fall of cardiac biomarkers. However, whether rising or falling patterns of high-sensitivity cardiac troponin T (hs-cTnT) improve the discrimination of ST-elevation myocardial infarction (non-STEMI) from non-acute coronary syndromes (ACS) has not been evaluated yet.

METHODS: We compared protocols of rising and falling absolute and relative hs-cTnT changes in an unselected emergency department population.

RESULTS: A total of 635 patients with unstable angina pectoris (UAP), non-STEMI, or acute symptoms and increased hs-cTnT (>99th percentile) were enrolled. Of these, 572 patients met the inclusion criteria of consistently rising patterns (n=254, 44.4%), consistently falling patterns (n=224, 39.2%), or falling patterns after an initial rise (n=94, 16.4%). Final diagnoses included 66 (11.5%) patients with UAP, 141 (24.7%) patients with non-STEMI, and 365 (63.8%) patients with hs-cTnT elevations not due to ACS. Rising values were found more frequently in patients with non-STEMI, as compared to non-ACS (OR 3.69, 95% CI 2.46-5.53; p<0.0001), and falling patterns were observed more frequently in patients with non-ACS conditions (OR 3.56, 95% CI 2.24-5.63; p<0.001). Addition of rising but not falling changes increased diagnostic performance of hs-cTnT concentrations at presentation: positive: AUC 0.680 (95% CI 0.618-0.742) vs. 0.861 (95% CI 0.822-0.900; p<0.0001), negative: AUC 0.678 (95% CI 0.545-0.812) vs. 0.741 (95% CI 0.635-0.847). A 20% criterion as proposed by ESC guidelines performed equally for positive and negative changes only when admission hs-cTnT values were considered: AUC 0.785 (95% CI 0.726-0.845) vs. AUC 0.763 (95% CI 0.681-0.845); p=ns.

CONCLUSIONS: Detection of rising but not falling hs-cTnT values improves discrimination of non-STEMI from non-ACS in an unselected emergency department population.