Plasma atrial natriuretic peptide, body weight and twenty-four-hour blood pressure monitoring in chronic hemodialysis patients.

In this study we investigated the interactions between volume changes (body weight), plasma atrial natriuretic peptide (pANP) and ambulatory blood pressure (BP) in 10 patients with end-stage renal disease undergoing regular hemodialysis (HD) treatment three times weekly. Most patients retained their diurnal BP variation when their BP was adequately controlled. Interdialytic weight gain was 1.3 +/- 0.2 kg and the day-time systolic BP increased 12.5 +/- 4.8 mm Hg on the second interdialytic day. pANP did not correlate (r = -0.07, p = 0.85) with this BP elevation, but there was a fairly strong positive correlation (r = 0.61, p = 0.06) between interdialytic weight gain and systolic BP. The mean pANP level decreased from 149.7 +/- 18.2 to 117 +/- 0.1 ng/l during HD and continued its decrease to 83 +/- 12.2 ng/l at 20 h after an HD session. The total decrease from 149.7 +/- 18.2 to 83 +/- 12.2 ng/l was statistically significant (p = 0.001). Since the lowest pANP value was found 20 h after completion of the dialysis session, body weight is a more reliable indicator of volume reduction during HD than pANP. The results indicate that in HD patients weight gain between two dialysis sessions increases the day-time systolic BP but not the diastolic BP. Diurnal BP variation is maintained as long as BP is adequately controlled either by volume control or by drug treatment.