Color Doppler and hormone replacement therapy: the role of thromboxane andplasma viscosity

The dim of the study war to evaluate the plasma thromboxane and plasma visc osity in relation with Doppler flow parameters in postmenopausal patients t reated with hormone replacement therapy. Thirty-two postmenopausal (follicle-stimulating hormone > 40 IU/l and estra diol < 100 pmol/l) women (mean age +/- SD, 54.7 +/- 2.9 years) participated in the study and were submitted to continuous estradiol transdermal supple mentation and 12-day courses of medroxyprogesterone acetate every second mo nth. Doppler resistances at the level of the uterine and internal carotid a rteries, thromboxane plasma levels and plasma viscosity were analyzed in ba sal condition and after 1, 3 and 6 months. During hormone supplementation, the pulsatility inner significantly decreas ed at the level of the analyzed arteries. Similarly, plasma thromboxane lev els and plasma viscosity were significantly reduced. Significant correlatio ns weve found between thromboxane plasma concentrations, plasma viscosity a nd uterine artery resistances. Thus hormone replacement therapy seems to be responsible for both direct and indirect modifications at the level of the vessel wall physiology.