Plasma levels of atrial natriuretic peptide and digoxin-like immunoreactive substances in intermittent peritoneal dialysis.

Plasma atrial natriuretic peptide (ANP) and digoxin-like immunoreactive substances (DLIS) levels were assayed in 10 patients on intermittent peritoneal dialysis (IPD) before and after a 12 hour dialysis session. Ultrafiltration volumes and blood pressures, pre and post dialysis were recorded. Left atrial diameter (LAD), as determined by M-mode echocardiography was measured prior to and at the end of each dialysis session. Ten age matched patients on hemodialysis (HD) served as controls. Predialysis plasma ANP was significantly higher in HD as compared to IPD patients and dialysis resulted in a significant decrease of plasma ANP in IPD and HD patients (37.9 +/- 28.0 to 23.1 +/- 28.5 and 201.9 +/- 110.7 to 117.0 +/- 75.6 pg/ml, respectively, p less than 0.05). Ultrafiltration volumes in IPD averaged 1840 +/- 645 ml/dialysis. The corresponding decrease in body weight in HD was 2000 +/- 220 g. Total DLIS levels in IPD and HD did not change with dialysis. LAD decrease significantly post dialysis (41.3 +/- 5.0 to 38.6 +/- 5.7 cm, p less than 0.001). Calculated ANP clearance during IPD was 5.6 +/- 3.9 ml/min. Plasma ANP correlated significantly with ultrafiltration volumes and LAD. It thus appears that ANP is sensitive to volume status in dialysed patients. Its dialysance, in IPD, approaches that of other middle molecules. Under the conditions tested ANP does not influence DLIS levels.