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

BACKGROUND: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.