Intraindividual comparison of ANP, cGMP and plasma catecholamines between HD and CAPD

Patients with end stage renal failure have elevated plasma levels of atrial natriuretic peptide (ANP) which seems to be a sensitive parameter of body fluid status. A prospective study comparing patients on hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) was still missing. Six identical patients (59 +/- 10 yrs, residual diuresis 1.3 +/- 0.61, 1 data expressed as means +/- SEM) were studied in the predialysis phase and under steady state conditions on HD and on CAPD. Plasma levels of ANP, cyclic guanosine monophosphate (cGMP), adrenaline, noradrenaline and dopamine were determined. Blood and dialysate samples were repeatedly taken. Ultrafiltration-volume, dry weight and blood pressure were not different between HD and CAPD. ANP and cGMP reached the highest plasma levels in the predialysis phase with 421 +/- 180 pg/ml and 19.8 +/- 6.4 pmol/ml and decreased after the onset of dialysis treatment. On HD mean ANP levels of 279 +/- 175 pg/ml were not significantly different from those on CAPD (320 +/- 213 pg/ml). However, cGMP concentrations on CAPD (15.7 +/- 5.4 pmol/ml) surpassed the values measured on HD (10.5 +/- 3.4 pmol/ml, p less than 0.05). Plasma noradrenaline was markedly elevated in the predialysis phase (421 +/- 180 pg/ml) and decreased under dialysis treatment. Differences between HD and CAPD were not found. Adrenaline and dopamine concentrations fell within the normal range.