Lack of Change in the Incidence of Unstable Angina after Transition to High-Sensitivity Cardiac Troponin T

Objective: This study evaluated the impact of high-sensitivity cardiac troponin T (hs-cTnT) implementation on the incidence and cardiac evaluations of patients with unstable angina. Methods: This was a retrospective U.S. cohort study of emergency department patients evaluated with cardiac troponin (cTn) measurements during the transition from 4th-generation cTnT (6 months pre-implementation) to 5th-generation hs-cTnT assay (6 months postimplementation). Results: Only 39 patients were diagnosed with unstable angina; 18 with 4th-generation cTnT and 21 with 5th-generation hs-cTnT. With 4th-generation cTnT assay, almost all (94.4%) had values < 99th upper reference limit, whereas 33.3% had at least one value > 99th (mean = 25ng/L and peak = 26 ng/L) with hs-cTnT assay. The latter had underlying structural heart disease. There were no significant differences in cardiac evaluations with echocardiography, stress testing, or invasive coronary angiography between the two groups. Conclusions: The incidence of unstable angina did not change with the transition to 5th-generation hs-cTnT assay. However, stable hs-cTnT increases were more common, likely due to underlying structural heart disease. There were no changes in the frequency of cardiac evaluations.