CALCIUM-ANTAGONISTS AND THIAZIDE DIURETICS HAVE OPPOSITE EFFECTS ON BLOOD RHEOLOGY AND RADIAL ARTERY COMPLIANCE IN ARTERIAL-HYPERTENSION - A RANDOMIZED DOUBLE-BLIND-STUDY

In addition to their effects on blood pressure, antihypertensive agent s may produce additional effects on blood rheology and arterial compli ance abnormalities which may play a role in target-organ damage. Howev er, these effects may depend only on the specific pharmacological prop erties of certain antihypertensive agents, and may be partly unrelated to blood pressure lowering action. We compared the effects of nitrend ipine 20 mg once daily to hydrochlorothiazide 25 mg once daily in 33 m ildly to moderately hypertensive and otherwise healthy patients, in a double blind parallel group trial. Blood rheology (blood frbrinogen an d protein concentrations, hematocrit, plasma viscosity and whole blood viscosity at shear rates 0.2 to 128 s(-1), erythrocyte deformability and aggregation) and radial artery diameter and compliance (Nius I + F inapres) were measured at baseline and after 2 months of treatment. Bo th drugs produced similar blood pressure lowering. Blood viscosity inc reased for all shear rates in the hydrochlorothiazide group and decrea sed in the nitrendipine treated group. Erythrocyte deformability incre ased in the nitrendipine but not in the thiazide group. Radial artery diameter and compliance were not different between the two groups but there was a trend towards an increase in cross-sectional compliance in the hydrochlorothiazide group and towards a decrease in the nitrendip ine group. Our data show that, in mildly hypertensive patients, blood pressure control by nitrendipine produced more favourable effects on r elevant rheological variables than hydrochlorothiazide. Radial artery compliance changes tended to be altered also in opposite directions by the two agents. The significance and the clinical relevance of these effects may require further investigations. (C) 1998 Elsevier, Paris.