[The blood rheology of diuretics]

We have studied a group of 33 (27 female and 6 male) patients suffering pure essential arterial hypertension, with a mean age of 54.06 years, and who received a daily monodose of chlortalidone. Arterial pressure, blood viscosity at different shearing levels, as well as those parameters capable of modifying this viscosity were determined at days 0, 30, 60, 90, and 180 of treatment. Similarly, blood viscosity in this group of patients on day 0 is compared to a normotense control group. We observed a statistically significant (p less than 0.05) increase in blood viscosity in the hypertense group at day 0 when compared to the control group. No significant changes due to treatment could be observed in blood viscosity or any of the parameters studied. However, there was a significant decrease (p less than 0.0001) in arterial blood viscosity. "Chronic" treatment of essential hypertense patients have an inherent increase in blood viscosity. "Chronic" treatment of essential arterial hypertension with diuretics (chlortalidone) does not modify the hematocrit nor other biochemical parameters studies, nor blood viscosity. Treatment normalises blood pressure levels, but it does not "primarily" hemodynamically prevent ischemic events at the microcirculatory level.