Mechanisms of hypertension induced by erythropoietin in patients on hemodialysis.

To investigate the mechanisms of hypertension induced by recombinant human erythropoietin (rHuEPO) in patients on hemodialysis (HD), mean blood pressure (MBP), plasma renin activity (PRA), whole blood viscosity, blood volume (BV), cardiac index (CI) and total peripheral resistance index (TPRI) were measured before and after treatment with rHuEPO for 3 months in 9 patients on HD. Pressor responsiveness to exogenous norepinephrine (NE) and angiotensin II (AII) were also compared before and after treatment. Four patients were 'responders' (R) whose MBP increased by more than 10 mmHg, and 5 patients were 'non-responders' (non-R) whose MBP was unchanged or increased by less than 10 mmHg. Initial PRA and TPRI were significantly higher and BV was significantly lower in R than in non-R. After treatment, TPRI was increased in both groups, but CI was decreased in non-R. There was a significant correlation between changes in MBP and blood viscosity to rHuEPO. Pressor responsiveness to NE and AII were significantly enhanced after rHuEPO treatment in responders. These results suggest that inappropriate cardiovascular responses to the correction of anemia, increased blood viscosity, and enhanced pressor responsiveness may participate in the development of rHuEPO-related hypertension.