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.