Plasma levels and dialysance of atrial natriuretic peptide in terminal renal failure.

Plasma immunoreactive atrial natriuretic peptide (irANP) levels, their chromatographic profile, relationship with hemodynamic variables, and responses to hemodialysis (HD) or postural changes were investigated in HD patients. Peripheral venous supine plasma irANP averaged 167 +/- 31 (+/- SEM) pg/ml in 12 normal subjects (age 63 +/- 2 yr). In 42 HD patients (mean age 65 +/- 1 yr), plasma irANP in peripheral arterio-venous fistulae was high (447 +/- 50 pg/ml, P less than 0.01) before HD and decreased (P less than 0.001) to 164 +/- 24 pg/ml after HD. The latter reduced body weight by -2.3 +/- 0.2 kg (P less than 0.001) and blood pressure from 139/77 +/- 4/2 to 126/73 +/- 4/2 mm Hg (P less than 0.01). Pre-dialysis plasma irANP in right atrium, pulmonary artery or avfistula correlated with pulmonary capillary wedge pressure (N = 10, r = 0.66 to 0.73; P less than 0.05); HD-induced changes in these variables were also correlated (r = 0.80 to 0.90; P less than 0.05 to less than 0.01). Compared with supine values, upright posture decreased plasma irANP in 12 normal subjects and 8 HD patients (-40 and -42%, respectively, P less than 0.01). IrANP clearance from plasma averaged 24 +/- 5 ml/min across the hemodialyzer (N = 6) and 46 +/- 3 ml/min across the hemofilter (N = 4). We conclude that in terminal renal failure, circulating irANP consists largely of alpha ANP, is often elevated before HD, decreases with the change from recumbency to standing, falls after removal of excess fluid, and may depend strongly on left atrial and pulmonary arterial pressures.(ABSTRACT TRUNCATED AT 250 WORDS)