Prohormone brain natriuretic peptide (proBNP), BNP and N-terminal-proBNP circulating levels in chronic hemodialysis patients. Correlation with ventricular function, fluid removal and effect of hemodiafiltration

Background: Brain natriuretic peptide (BNP), N-terminal proBNP (NT-proBNP) and to a lesser extent prohormone proBNP are recognized as biochemical markers of left ventricular dysfunction. In renal failure, interpretation of natriuretic peptide remains unclear, as natriuretic peptide levels may be not only be dependent on cardiac function and dimensions but also on renal function, fluid volume and removal by dialysis procedure including hemodiafiltration (HDF). The purpose of this study was (i) to assess BNP, NT-proBNP and proBNP levels and their correlation with clinical and echocardiographic data in chronic hemodialysis patients, and (ii) to investigate basal level alteration following HDF. Methods: Baseline clinical and echocardiographic parameters were collected in 31 dialysis patients without evidence of cardiac failure. Pre- and post-HDF BNP, NT-proBNP and proBNP concentrations were measured. Correlations between echocardiographic measurements and basal circulating peptides, between changes in peptide values and changes in fluid volume after HDF were investigated. Results: Baseline plasmatic levels were elevated (BNP = 517 +/- 840 pg/mL, NT-proBNP = 5340 +/- 6132 pg/mL and proBNP = 3569 +/- 4683 pg/mL) and correlated with left auricular diameter and left ventricular mass index. HDF session induced a significant decrease of 39%, 59% and 36% for BNP, NT-proBNP and proBNP levels, respectively. This decrease was not correlated to post-HDF fluid removal or weight decrease. Correlation between BNP and proBNP was stronger (r(2) = 0.88) than between NT-proBNP and proBNP (r(2) = 0.54). Conclusions: Despite their elimination, BNP, NT-proBNP and proBNP could be potential markers of left ventricular remodeling in chronic renal failure patients on hemodialysis. According to these results, their cut-off values, however, need to be re-evaluated.