Comparison of the diagnostic performance of three natriuretic peptides in hemodialysis patients: which is the appropriate biomarker?.

BACKGROUND Plasma concentrations of natriuretic peptides are often elevated in chronic hemodialysis patients and difficult to interpret due to accumulation, high incidence of cardiac disease and changes in volume status. Mid-regional pro-ANP is a newly developed assay whereas BNP and its fragment NT-pro-BNP are available for a longer time. In this cross-sectional study, we compared the plasma concentration of MR-pro-ANP, BNP and NT-pro-BNP in stable ambulatory hemodialysis patients (n = 239) and investigated their associations with clinical factors such as residual diuresis, cardiac status and interdialytic weight gain and with mortality. METHODS AND RESULTS In all patients enrolled, the plasma concentration of all natriuretic peptides were largely elevated with a median concentration of 337 pg/ml (interquartile range 146-684) for BNP, 4435 pg/ml (1687-16228) for NT-proBNP and 907 pmol/L (650-1298) for MR-pro-ANP. Plasma concentration of all natriuretic peptides correlated independently with age, degree of systolic dysfunction and negatively with residual diuresis. Dependency on residual renal clearance was strongest for the fragments MR-pro-ANP and NT-pro-BNP. The plasma concentration of all natriuretic peptides was associated with mortality within 2 years of follow-up. Receiver-operated curves revealed a low sensitivity (32-45%), but high specificity for all natriuretic peptides (85-93%) resulting in a high negative predictive (82-87%). Best cut-off values obtained from were 18 611 pg/ml for NT-pro-BNP, 958 pg/ml for BNP and 1684 pmol/L for MR-pro-ANP. CONCLUSIONS In hemodialysis patients, the fragments NTproBNP and MR-pro-ANP are largely elevated compared to BNP which is explained by accumulation. The prognostic performance of MR-pro-ANP is similar to that of NT-pro-BNP or BNP.