High-sensitivity cardiac troponin T, left ventricular function, and outcome in non–ST elevation acute coronary syndrome

Abstract

Cardiac troponin (cTn) levels reflect infarct size and depressed left ventricular ejection fraction (LVEF) in patients with non-ST elevation acute coronary syndrome (NSTE-ACS). However, there is very limited information on whether cTn measured with a high-sensitivity (hs) assay would provide incremental prognostic information to the LVEF in NSTE-ACS patients. This was a registry-based study (SWEDEHEART registry) investigating 20,652 NSTE-ACS patients with available information on hs-cTnT (highest level recorded during the hospitalization) and the LVEF estimated using echocardiography. All patients had been followed for 1 year. Hs-cTnT levels independently predicted major cardiovascular events (MACE) in cohorts with normal, slightly depressed, moderately depressed, and severely depressed LVEF. The adjusted hazard ratios in these cohorts were 1.18 (95% CI 1.13-1.23), 1.12 (95% CI 1.06-1.18), 1.12 (95% CI 1.06-1.19), and 1.21 (95% CI 1.13-1.30), respectively. Hs-cTnT levels were particularly predictive for cardiovascular mortality and readmission for heart failure. Excluding patients with previous cardiac disease did not affect the overall interrelations of hs-cTnT and LVEF with MACE. Hs-cTnT levels provide incremental prognostic value independent of the LVEF in patients with NSTE-ACS. Hs-cTnT is particularly predictive for MACE in patients with severely depressed LVEF but also in those with a normal LVEF. Accordingly, a normal LVEF should not be used as an argument not to target patients to thorough workup.