Doppler ultrasonographic studies of the vascular resistance of the uterineartery in the mare associated with vasoactive and antikoagulative theory

In seven mares with endometrial biopsies graded either I or IIA (Schoon et al., 1992) the resistance of the uterine artery wall was measured by Dopple r sonography to investigate the influence of the vascactive substances isox suprine, acepromacine, heparin and phenprocoumon. Isoxsuprine and acepromac ine ore known to act directly at the vessel wall. In the present study coul d be demonstrated that these substances cause an increase in the wall resis tance compared to basic values. These investigations were carried out on si x mares on two successive days during diestrus. In 4 mares treated with a l ow-dose-regimen of heparin (Gerhards und Eberhardt, 1988) on four days duri ng diestrus the wall resistance decreased compared to corresponding values of untreated cycles as well as to basic values at the onset of the treatmen t period. One more was treated with phenprocoumone for two cycles. The dosi s was chosen according to the results of daily performed coagulating blood tests. The resistance decreased gradually before ovulation compared to untr eated cycles. The use of anticoagulating substances seems promissing in the therapy of pathological uterine blood flow.