Hemorheological investigations in patients with polycystic kidney disease

Polycystic kidney disease (PKD) is associated with an increased incidence of hypertension and cardiovascular abnormalities. As hemorheology is an important hemodynamic determinant and may contribute to vasculopathies we measured whole blood viscosity and red blood cell (RBC) and plasma rheological factors in 38 patients with PKD and compared this data with similar measurements in age- and sex-matched healthy controls. Renal function was assessed by plasma creatinine concentration. Analysis of the data showed that the PKD group had a significant reduction in mean hematocrit and an increase in mean plasma viscosity and mean plasma fibrinogen concentration. Intrinsic RBC rheology assessed by standardised viscosity measurements was impaired in patients with PKD compared to control subjects. The changes in plasma and RBC rheology did not however result in increased whole blood viscosity in the patients with PKD due to the reduction in hematocrit level. Correlation analyses demonstrated a significant relationship between increased plasma creatinine concentration and lower hematocrit, decreased whole blood viscosity and impaired RBC deformability but not with increased plasma viscosity or plasma fibrinogen concentration. This study shows that although PKD is associated with mild abnormalities in plasma rheology and intrinsic RBC rheology these changes are offset by a reduction in hematocrit. The changes in RBC rheological determinants in PKD appeared to be related to the degree of renal impairment.