High-sensitivity cardiac troponin T increases after stress echocardiography.

INTRODUCTION: Exercise (ESE) and dobutamine stress echocardiography (DSE) have high sensitivity and specificity to detect inducible myocardial ischemia in patients with significant coronary artery disease (CAD). High-sensitivity cardiac troponin (hs-cTn) assays detect troponin concentrations in the ng/L range. The aim of this study was to determine the kinetics of hs-cTnT in patients undergoing ESE and DSE and possible association of hs-cTnT with inducible myocardial ischemia.

METHODS: In this prospective study adult patients undergoing ESE/DSE were enrolled. Peripheral blood samples were obtained before, and 30 min, 1, 2, and 4-6 h after completion of ESE/DSE. Hs-cTnT was measured on a Roche Diagnostics Elecsys 2010 analyzer.

RESULTS: We enrolled 48 patients (33 ESE and 15 DSE); 11 patients (23%) had elevated baseline hs-cTnT concentrations >14 ng/L (99th percentile URL); 31/48 (65%) developed an hs-cTnT increase after ESE/DSE (peak 4-6 h post stress test), but only three patients (all in ESE group) had a positive stress test. Absolute and relative hs-cTnT increases were higher after DSE (median Δhs-cTnT +9.7 ng/L [IQR 4.5, 27.2]; +123% [IQR 49, 271]) compared to ESE (median Δhs-cTnT +2.3 ng/L [IQR 1, 4.9]; +37% [IQR 9.1, 221]).

CONCLUSIONS: One in four patients undergoing ESE/DSE had increased hs-cTnT values prior to stress testing. Hs-cTnT increased above the upper limit of normal occurred commonly after ESE/DSE but was more pronounced after DSE. Increases in hs-cTn did not appear to be associated with inducible myocardial ischemia. These findings may have important implications for the clinical use of hs-cTnT within 6 h after ESE/DSE.