PLASMA NATRIURETIC PEPTIDES AND CARDIAC VOLUME DURING ACUTE CHANGES IN INTRAVASCULAR VOLUME IN HEMODIALYSIS-PATIENTS

1. Plasma levels of atrial natriuretic peptide (ANP) and brain natriur etic peptides (BNP) were measured, along with left and right atrial an d left ventricular volumes, in eight patients with chronic renal failu re before and after the removal of 2.1+/-0.61 of fluid by ultrafiltrat ion and again during volume repletion with intravenous sodium chloride solution (150 mmol/l saline) to restore body weight plus 0.5 kg. 2. B aseline levels of ANP (46.0+/-7.5 pmol/l) and BNP (22.0+/-4.4 pmol/l) were elevated above normal. There was a significant reduction in plasm a ANP (26.5+/-4.7 pmol/l, P<0.05) and BNP (19.1+/-4.9 pmol/l, P<0.05)) following ultrafiltration. Changes in plasma ANP during ultrafiltrati on correlated significantly with changes in left atrial volume (r=0.64 3, P<0.05). 3. During volume repletion there was an exaggerated releas e of ANP (mean level post repletion 71.3+/-20.8 pmol/l) which was not paralleled by changes in BNP. Changes in BNP were small, showing no co rrelation with atrial or ventricular volumes during either ultrafiltra tion or volume repletion. 4. These findings indicate that in chronic r enal failure without left ventricular dysfunction, moderate acute chan ges in volume status elict only small immediate responses in plasma BN P. Changes in plasma ANP are greater than BNP and more responsive to c hanges in left atrial volume.