Comparison of Prognostic Value of High-sensitivity and Conventional Troponin T in Patients with Non-ST-segment Elevation Acute Coronary Syndromes

Background: The impact of high-sensitivity troponin assays on risk stratification of patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS) is unknown.

Methods: The study included 447 patients with NSTE-ACS. Cardiac troponin T (TnT) was measured with conventional and high-sensitivity assays, in parallel, using the same plasma sample. The primary end-point was 4-year mortality.

Results: The use of cut-off of 0.014 μg/L of high-sensitivity TnT (hs-TnT) instead of 0.01 μg/L of the conventional (cTnT) increased proportion of non-ST-segment elevation myocardial infarction (NSTEMI) patients by 33% (from 201 to 268 patients). Re-classified patients from unstable angina to NSTEMI had similar 4-year mortality compared to patients with NSTEMI by both assays: 16 deaths (25.1%) among 67 re-classified patients versus 47 deaths (23.6%) among patients diagnosed with NSTEMI by both assays; odds ratio=1.03, 95% confidence interval [CI] 0.53-1.97; P=0.933). The Cox model identified hsTnT (hazard ratio=2.59, 95% CI 1.22-5.50; P=0.013 for hsTnT>0.014μg/L versus hsTnT ≤ 0.014 μg/L) as an independent correlate of 4-year mortality. hsTnT significantly improved prediction of the four-year mortality (relative integrated discrimination improvement 8.2%, P=0.005).

Conclusions: The use of hsTnT instead of cTnT increased the proportion of patients with NSTEMI among patients with NSTE-ACS and significantly improved risk stratification regarding long-term mortality.