Blood B-type natriuretic peptide and dialysis: present assessment and future analyses.

Brain natriuretic peptide (BNP) is elevated in hemodialysis (HD) patients and predicts increased mortality. Intra- and interdialytic changes in BNP have not been fully described. End-stage renal disease (ESRD) patients were prospectively recruited at three dialysis centers. At five visits, over a 6-week period, pre- and postdialysis BNP levels were measured. Pre- and postdialysis weights, blood pressure, fluid removed/given and demographic/medical information were recorded. Mean pre- and post-HD BNP (log-transformed) was not significantly different and did not correlate with fluid removed. Both pre- and post-HD BNP significantly decreased across the dialysis week (Pre-HD: intercept = 2.69, slope = -0.097, t = -6.7, P < 0.001) and across the five sessions (slope = -0.046, t = -2.47, P = 0.01). Interdialytic BNP changes are not related to fluid removed. Chronic volume overload and increased left ventricular wall tension likely account for the BNP decrease across dialysis weeks and may be related to higher death rates among HD patients at the beginning of the week.