Usefulness of pulsatility and resistive index for detection of mares with and without endometritis

Abstract

Endometritis, a condition which causes inflammatory or degenerative alterations of the endometrium, is one of the most serious causes of infertility or subfertility in equine reproduction, whether associated or not with the presence of infectious agents (Mattos et al. Revista Brasileira de Reprodução Animal. 2003; 27:150-156). A complementary diagnosis, carried out with the use of Doppler ultrasonography (US), will enable an assessment of local blood flow and a more accurate analysis of the physiology of the ovaries and uterus (Ginther et al. Animal Reproduction Science. 2007; 102:314-321; Ferreira et al. Ciência Rural. 2011; 41:1063-1069). The main purpose of the present study was to assess potential alterations in the uterine vasculature of mares with clinical or subclinical endometritis and mares with no endometritis. Twenty-one mares were organized into three groups: CG: without endometritis; GCE: with clinical endometritis; GSE: with subclinical endometritis. In the latter group, mares had no alteration in the B-mode US but had positive cytology and/or bacterial and/or fungal culture. Based on this, the estrous cycle was closely observed until the preovulatory follicle appeared and subsequently, samples were collected for cytological examination, bacterial and fungal culture. After the induction and detection of ovulation, B-mode transrectal US and spectral-mode Doppler US of the left and right uterine arteries near the bifurcation with internal iliac arteries was undertaken.These ultrasound examinations were performed on a daily basis, until the next ovulation so that the complete estrous cycle could be assessed. Statistical analysis was performed by means of ANOVA using the Tukey test for one factor. According to the results of this study, no statistical difference was found in the evaluation of the pulsatility index between groups of mares without endometritis (158.71±38.27) and with subclinical endometritis (166.60±41.68) and between groups with subclinical (166.60±41.68) and clinical endometritis (171.27±44.75). However, a significant statistical difference was observed in the pulsatility index between groups of mares without endometritis (158.71±38.27) and mares with clinical endometritis (171.27±44.75) (p<0.01). As for the evaluation of the resistive indices, no statistical difference was observed between the groups of mares with subclinical (0.72±0.08) and clinical (0.72±0.08) endometritis. However, a statistically significant difference was identified in the resistive index between groups of mares without endometritis (0.69±0.07) and subclinical endometritis and clinical endometritis (p<0.01). Thus, the indexes evaluated were inversely proportional to vascular perfusion. It is concluded that spectral mode Doppler ultrasonography can be used as a complementary diagnostic tool in the identification of subclinical and clinical endometritis, by evaluating vascular perfusion of the uterine arteries.