Risk stratification in stable coronary artery disease is possible at cardiac troponin levels below conventional detection and is improved by use of N-terminal pro-B-type natriuretic peptide

Abstract

Aims

Low prevalence of detectable cardiac troponin in healthy people and low-risk patients previously curtailed its use. With a new high-sensitive cardiac troponin assay (hs-cTnT), concentrations below conventional detection may have prognostic value, notably in combination with N-terminal pro-B-type natriuretic peptide (NT-pro-BNP).

Methods and results

Biomarker concentrations were determined from serum obtained at enrolment in the CLARICOR trial involving 4197 patients with stable coronary artery disease (CAD) followed for 2.6 years. Serum hs-cTnT was detectable (above 3 ng/l) in 78% and above the conventional 99th percentile (13.5 ng/l) in 23%. Across all levels of hs-cTnT there was a graded increase in the risk of cardiovascular death after adjustment for known prognostic indicators: hazard ratio (HR) per unit increase in the natural logarithm of the hs-cTnT level, 1.49; 95% confidence interval (CI), 1.23–1.81; similarly for all-cause mortality (HR 1.48, 95% CI 1.29–1.70) and myocardial infarction (HR 1.37, 95% CI 1.13–1.67). Increasing values of hs-cTnT were associated with increased mortality across all values of NT-pro-BNP, but this was particularly prominent when NT-pro-BNP >400 ng/l.

Conclusions

In patients with stable CAD, any detectable hs-cTnT level is significantly associated with all-cause mortality, cardiovascular death, and myocardial infarction after adjustment for traditional risk factors and NT-pro-BNP. Excess mortality is particularly pronounced in patients with NT-pro-BNP >400 ng/l.