Circulating Cardiac Troponin I Levels Measured by a Novel Highly Sensitive Assay in Acute Decompensated Heart Failure: Insights From the ASCEND-HF Trial

BACKGROUND: Circulating cardiac troponin levels (cTn), representative of myocardial injury, are commonly elevated in heart failure (HF) and related to adverse clinical events. However, whether cTn represents a spectrum of risk in HF is unclear. METHODS: Baseline, 48-72-hour, and 30-day plasma cTnI was measured with the use of a new highly sensitive assay in 900 subjects with acute decompensated HF (ADHF) in ASCEND-HF. Multivariable models determined the relationship between cTnI and outcomes. RESULTS: The median (interquartile range) cTnI was 16.4 (9.3-31.6) ng/L at baseline, 14.1 (7.8-29.7) ng/L at 48-72 hours, and 11.6 (6.8-22.5) ng/L at 30 days. After additional adjustment for N-terminal pro-B-type natriuretic peptide (NT-proBNP) to established risk predictors, both baseline (odds ratio [OR] 1.25; P = .03) and 48-72-hour (OR 1.43; P = .001) cTnI were associated with higher risk for death or worsening HF before discharge. However, only cTnI at 30 days was associated with 180-day death (hazard ratio 1.25; P = .007). There were no curvilinear associations between changing cTnI and clinical outcomes. CONCLUSIONS: Circulating cTnI level was associated with clinical outcomes in ADHF, but these observations diminished with additional adjustment for NT-proBNP. Although they likely represent a spectrum of risk in ADHF, these findings question the implications of changing cTnI levels during treatment.