Background: In patients with heart failure (HF), increased arginine vasopressin concentrations are associated with more severe disease, making arginine vasopressin an attractive target for therapy. However, AVP is difficult to measure due to its in vitro instability and rapid clearance. Copeptin, the C-terminal segment of preprovasopressin, is a stable and reliable surrogate biomarker for serum arginine vasopressin concentrations.

Results: The Biomarkers in Acute Heart Failure (BACH) trial was a 15-center, diagnostic and prognostic study of 1641 patients with acute dyspnea; 557 patients with acute HF were included in this analysis. Copeptin and other biomarker measurements were performed by a core laboratory at the University of Maryland. Patients were followed for up to 90 days after initial evaluation for the primary end point of all-cause mortality, HF-related readmissions, and HF-related emergency department visits. Patients with copeptin concentrations in the highest quartile had increased 90-day mortality (P<0.001; hazard ratio, 3.85). Mortality was significantly increased in patients with elevated copeptin and hyponatremia (P<0.001; hazard ratio, 7.36). Combined end points of mortality, readmissions, and emergency department visits were significantly increased in patients with elevated copeptin. There was no correlation between copeptin and sodium (r=0.047).

Conclusions: This study showed significantly increased 90-day mortality, readmissions, and emergency department visits in patients with elevated copeptin, especially in those with hyponatremia. Copeptin was highly prognostic for 90-day adverse events in patients with acute HF, adding prognostic value to clinical predictors, ser um sodium, and natriuretic peptides. Background: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00537628.