Triplex Doppler Ultrassonography in Prenatal of Pregnant Bitches

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Processo FAPESP: 10/16913-7

Processo FAPESP: 11/06011-9

Background: The Dopplerfluxometry is a diagnostic technique that provides anatomical information and real-time dynamic tissue evaluation by determining the presence and direction of blood flow in a vessel and their hemodynamic features. Considering the importance of Doppler to pregnant women and the recent studies of vascular indices in pregnant animals and the application of news technologies for Doppler ultrasonography as spectral and power techonology, the objective of this study was to determine the absolute values of the vascular indices from the uterine, umbilical and fetal aorta arteries in pregnant bitches, using new techniques of doppler ultrassonography.Materials, Methods & Results: Twenty six multiparous bitches from the same kennel, weighting 5 - 25 kg, aged 4 - 6 years old, were selected to the current study. Doppler ultrasonography was performed to assess the maximum and minimum velocity, resistance and pulsatility indices of the uteroplacental, umbilical and fetal abdominal aorta arteries (5th, 6th, 7th and 8th gestational week). The mean pregnancy period in twenty six bitches was 60 days and the mean number of puppies per pregnancy was four. Twenty five animals presented healthy pregnancies and one presented hydrallantois at the 7th and 8th gestational week. During Doppler exams in healthy pregnant bitches, there were progressive increase in PSV (P < 5 %) to the uteroplacental, fetal aorta and umbical arteries, constant values in the uteroplacental artery EDV (P > 5 %) but increased EDV (P < 5 %) in umbilical and fetal aorta and decreased PI and RI in the vessels evaluated (P < 5 %). For the bicthe with hydrallantois was observed EDV = 3 cm / s, PI and RI of 1.82 to 1.46; PSV was 11 cm/s, EDV = 2.1 c/ms, PI = 1.46 and RI = 0.76 at the 7th and 8th week of pregnancy, respectively, different values from those obtained in healthy bitches.Discussion: In agreement with these authors and complementing the research carried with unpublished data for veterinary medicine and power technology (as the real values of PSV and EDV obtained between the 5th and 8th gestational week), the present study suggests that this method is useful for diagnosis of pregnancy pathologies, during different stages of pregnancy in bitches. It was verified by the results obtained that, in pregnant healthy bitches, the indices (PSV and EDV) of uteroplacental, umbilical and fetal aorta arteries increased progressively with the evolution of pregnancy and PI and RI decrease progressively. The progressive development of the fetal circulation coupled with the appearance of a diastolic peak velocity in these arteries, there is a drop the values of RI and PI decrease in the umbilical artery and RI decrease in the aorta artery. The increase of PSV and EDV values demonstrates the necessity of the body to intensify the maternal-fetal circulation, with consequent nutrient infusion and tissue development. In general, the physiological behavior of blood flow for the vascular indices observed is due to the development of gestational structures and maturation of placental and fetal circulation. Regarding pathological pregnancy. The vascular indices were different during the final stage of the gestation process. These findings reaffirm the idea that, in abnormal bitches pregnancies, there is a reduction in blood flow and higher resistance in the umbilical placental microcirculation. Thus, it was concluded that the maternal-fetal Doppler and power technology is a useful technique for prenatal diagnosis of pathological pregnancies in bitches.