Role for precursor Pro-B type natriuretic peptide in assessing response to therapy and prognosis in patients with decompensated heart failure treated with nesiritide.

BACKGROUND: ProBNP, the precursor peptide to BNP and NT-proBNP (NP), circulates in patients with chronic heart failure (HF) and appears to be the predominant form of NP. This heterogeneity may confound interpretation of NP concentrations. The aim of this study was to evaluate the response to therapy and prognostic influence of proBNP in a cohort of patients admitted to hospital for decompensated HF.
METHODS: We prospectively evaluated 40 Class III-IV patients who received clinically-indicated nesiritide infusions as part of their care. Blood was drawn before, during, and post-infusion, and assayed for proBNP, BNP, and NT-proBNP.
RESULTS: All biomarkers were increased at baseline consistent with HF. ProBNP and NT-proBNP demonstrated significant reductions in response to therapy (42% and 18% post-infusion, respectively). In the patients who experienced post-hospital mortality (40% at 6 months), baseline proBNP and BNP concentrations were significantly lower than in survivors. This paradoxical finding may be explained by the end-stage nature of this patient cohort possibly experiencing exhaustion of their NP systems.
CONCLUSIONS: Circulating concentrations of proBNP are increased in decompensated HF and similar to NT-proBNP are reduced in response to acute therapy. Paradoxically and similar to BNP, baseline proBNP concentrations were lower in post-hospital non-survivors. While hypothesis generating, the results of this study support a role for proBNP in monitoring therapy and predicting short-term outcome. These findings need to be confirmed in a patient cohort without nesiritide therapy and more moderate HF.