Plasma Endothelin Levels and Blood Pressure in Hemodialysis and in Capd Patients. Effect of Subcutaneous Erythropoietin Replacement Therapy

We investigated plasma endothelin (ET) concentration and blood pressure in 44 patients with end stage renal failure chronically treated with either hemodialysis (n = 24) or continuous ambulatory peritoneal dialysis (CAPD) (n = 20). Half of the subjects were on chronic erythropoietin (r-HuEPO) replacement therapy (30-60 U/kg) subcutaneously, 3 times weekly. The mean plasma ET level of the whole group was about five fold higher than the normal range. Plasma ET concentration and mean blood pressure were higher in hemodialysis than in CAPD patients (33.3 +/- 2.1 vs 24.8 +/- 1.2 pg/ml, p < 0.01, and 101 +/- 2.4 vs 91 +/- 3 mmHg, p < 0.025). There was a significant correlation between plasma ET levels and systolic blood pressures in both groups (r = 0.45, p < 0.05). Patients (hemodialysis and CAPD) receiving subcutaneous r-HuEPO had higher mean blood pressure (99 +/- 3 vs 85 +/- 4 mmHg, p < 0.01), while their plasma ET levels were similar to untreated patients independent of the dialysis mode. However, a statistically significant correlation between plasma ET and systolic blood pressure was present only in the r-HuEPO treated group (r = 0.46, p < 0.05 vs r = 0.29, N.S., for the untreated group). These results show that plasma ET levels are markedly increased on both dialysis mode, but the values are lower in CAPD patients. Plasma ET concentrations significantly correlated with systolic blood pressures in the whole group of patients, and also in those receiving r-HuEPO replacement therapy.