Cerebral hemodynamic changes following treatment with erythropoietin

Adverse hemorheologic effects induced by erythropoietin (EPO) treatment of renal anemia may pose a cerebrovascular risk. We therefore investigated the changes in cerebral perfusion, cerebral blood flow velocity (BFV) and neuropsychologic performance in 11 patients (mean age 37 years) receiving EPO. In response to EPO there was a significant (p less than 0.01) increase in hematocrit (35%), hemoglobin (43%) and whole-blood viscosity (50% at high and 90% at low shear rate). The initially increased blood flow velocity dropped significantly (p less than 0.05) and returned toward normal values in the middle cerebral arteries and the basilar artery (22 and 19% decrease, respectively). Global cerebral blood flow (CBF) decreased by 10% (not significant). The score of the Wechsler Adult Intelligence Scale digit symbol test improved significantly (p less than 0.01) after EPO treatment. None of the patients developed cerebrovascular symptoms or side effects. We conclude that the hematologic and rheologic changes following EPO treatment cause CBF and BFV to return toward normal and improve neuropsychologic performance in patients with end-stage renal disease.