Nephrol Dial Transplant (1993) 8: 621-625
© 1993 European Renal Association-European Dialysis and Transplant Association
research-article
Influence of blood volume on the blood pressure of predialysis and peritoneal dialysis patients treated with erythropoietin
1Department of Renal Medicine, Manchester Royal Infirmary Manchester, UK 2University Department of Haematology, Manchester Royal Infirmary Manchester, UK
Correspondence and offprint requests to: Correspondence and offprint requests to: Dr E. Anastassiades, Flat 1, 11 Brondesbury Park, London NW6 7BS, UK
Twenty-seven patients with renal failure (16 on CAPD and 11 predialysis) were treated with erythropoietin. At 12 weeks, the mean haemoglobin concentration (±SEM) in the CAPD patients had increased from 7.07 ± 0.20 to 10.88 ± 0.45 g/dl (two-tailed paired t test, P<0.0001) and in the predialysis patients from 6.90 ±0.35 to 10.05 ± 0.47 g/dl (P< 0.0001). Predialysis patients were taking more antihypertensive medication at baseline. No increase was required in either group after erythropoietin; there was no change in blood pressure in the CAPD patients, though in the predialysis patients the systolic blood pressure rose slightly from 132 to 146 mmHg (P=0.029) and the mean blood pressure from 95 to 103 mmHg (P=0.028).
In 12 patients (6 on CAPD and 6 predialysis) the red cell volume, plasma volume, and total blood volume were measured before and after treatment. In the CAPD patients there was a marked expansion of the red cell volume from 912±127 to 1471±222 ml (P=0.004) and a concomitant contraction of the plasma volume from 3932 ±250 to 3178 ±326 ml (P=0.005), leaving the blood volume unchanged from 4843 ± 352 to 4649 ±503 ml. Predialysis patients had a similar expansion of the red cell volume from 733 ± 59 to 1304± 161 ml (P=0.017) but no contraction of the plasma volume (from 3417 ±354 to 3314 ±260 ml), so that the blood volume tended to expand from 4149 ±347 to 4618 ±414 ml (P= 0.053). The mean contraction of the plasma volume in the predialysis group was trivial (– 102 ±214 ml), whereas in the CAPD group it was large (–754 ±158 ml, P=0.034, two-tailed unpaired t test). Thereby the predialysis group experienced an expansion of the total blood volume of 469±186ml, whereas the CAPD group experienced a contraction of the blood volume of –195±189 ml(P=0.031).
We conclude that (a) increased blood volume may contribute to the exacerbation of hypertension induced by erythropoietin therapy; (b) gradual reduction of plasma volume, aiming for a stable total blood volume, is an important strategy for the prevention and control of erythropoietin-induced hypertension; (c) as reduction of plasma volume may be more problematic in predialysis patients, adequate blood pressure control may consequently be slightly more difficult, placing more reliance on antihypertensive medication.
Keywords: blood volume; CAPD; erythropoietin; hypertension; predialysis