Prognostic value of serial measurements of highly sensitive cardiac troponin I in stable outpatients with nonischemic chronic heart failure

Background: Cardiac troponin I (cTnI) is a useful biomarker in patients with chronic heart failure (CHF), and a highly sensitive cTnI (hs-cTnI) commercial assay has become available. However, the prognostic role of serial measurements of hs-cTnI in stable outpatients with CHF remains unknown.

Methods: At entry to the study, we evaluated 95 stable outpatients with nonischemic CHF showing a serum hs-cTnI (Centaur TnI-Ultra [Siemens Medical Solution Diagnostics, New York, NY], lower limit of detection 0.006 ng/mL) value ≥0.006 ng/mL. To evaluate the role of repetitive measurements of hs-cTnI, we performed echocardiography and measured serum levels of cTnI and N-terminal proBNP at baseline and 6 months later and then prospectively followed up these patients for 4.25 years.

Results: During long-term follow-up, there were 27 cardiac deaths. On multivariate analyses, high plasma N-terminal pro-brain natriuretic peptide (≥711 pg/mL, P = .0008), high serum hs-cTnI at baseline (≥0.03 ng/mL, P = .0011), and an increase in hs-cTnI (Δhs-cTnI ≥0 ng/mL, P = .022) after 6 months were independent significant prognostic predictors. The hazard ratio for mortality of patients with high hs-cTnI (≥0.03 ng/mL) and an increase in hs-cTnI (Δhs-cTnI ≥0 ng/mL) was 3.59 (95% CI 1.3-9.9, P = .014) compared with that of those with high hs-cTnI (≥0.03 ng/mL) and a decrease in hs-cTnI (Δhs-cTnI <0 ng/mL).

Conclusions: These findings indicated that not only the serum concentration of hs-cTnI at baseline but also an increase in hs-cTnI were independent and useful prognostic predictors in patients with nonischemic CHF.