Qual o melhor período para a realização do doppler das artérias uterinas na predição de complicações da gestação?

Transrectal Doppler sonography of uterine blood flow in ewes during pregnancy

In sheep, there is a lack of information on the behaviour of hemodynamic indices and parameters of blood flow velocity of the uterine artery during pregnancy, making it impossible to determine the real meaning of the values found and their probable relevance in normal physiological or pathological states. The objective of the present study was to evaluate the blood flow velocity parameters and hemodynamic indices of the uterine artery in ewes (18) during pregnancy (33). Based on non-invasive colour Doppler sonography, we evaluated the peak systolic velocity (PS), end diastolic velocity (ED), time-averaged maximum and minimum velocity in a cardiac cycle (TAMAX and TAMEAN), pulsatility index (PI), resistance index (RI), systolic/diastolic ratio (S/D), heart rate (HR), arterial diameter (AD) and the blood flow volume (BFV). Examinations started on day 28 and continued at two-week intervals until parturition. The Doppler parameters and the diameter of the uterine artery underwent significant changes during pregnancy. In the evaluated animals, indices related to resistance of the uterine artery, namely the impedance of blood flow, decreased throughout the initial, middle and late stages of gestation (PI: 1.15, 1.04, 0.97; RI: 0.61, 0.59, 0.57; S/D: 2.68, 2.52, 2.39, respectively) (p < 0.05). In contrast, the contents related to higher uterine irrigation increased during gestation (PS, ED, TAMAX, TAMEAN, HR, AD and BFV) (p < 0.05). No differences were found between the means of the variables in relation to the right and left uterine arteries and between single and multiple pregnancies in the hemodynamic indices. The present study is the first to demonstrate changes in uterine hemodynamics throughout pregnancy in sheep.

Third-trimester abnormal uterine artery Doppler findings are associated with adverse pregnancy outcomes

OBJECTIVES

To evaluate the association between third-trimester abnormal uterine artery Doppler findings and pregnancy outcomes.

METHODS

A prospective study was designed, including 198 consecutive singleton pregnancies between 27 and 41 weeks' gestation. In the study population, 144 had normal uterine artery Doppler waveforms, 37 had unilateral pathologic waveforms, and 17 had bilateral pathologic waveforms. Eighty patients had intrauterine growth restriction (IUGR), preeclampsia toxemia, or both, and 118 had no complications and served as a control group. The uterine artery Doppler waveform was considered abnormal when a notch or pulsatility index above the 90th percentile was noted.

RESULTS

In patients with bilateral pathologic uterine artery Doppler waveforms, the rates of cesarean delivery, small-for-gestational-age (SGA) neonates, preterm delivery, and low Apgar scores were increased compared to patients with normal or pathologic unilateral waveforms (P = .009; P > .001; P = .007; P > .001, respectively). The incidence rates for SGA neonates, cesarean delivery, and preterm delivery were significantly higher among patients without IUGR or preeclampsia toxemia when associated with pathologic bilateral waveforms in comparison to normal waveforms (P = .01 for all). A bilateral pathologic waveform was found to be an independent risk factor for cesarean delivery and SGA neonates. The incidence rates for SGA neonates and preterm delivery were significantly higher among patients with IUGR and/or preeclampsia toxemia when associated with bilateral abnormalities in comparison to normal waveforms (P = .01 for both).

CONCLUSIONS

Third-trimester abnormal uterine artery Doppler findings are associated with worse perinatal outcomes among patients both with and without pregnancy complications.

Doppler e marcadores séricos maternos na predição de complicações da gestação

OBJETIVO: Comparar a eficácia do Doppler das artérias uterinas e de marcadores séricos maternos na predição de complicações da gestação. MATERIAIS E MÉTODOS: Trata-se de um estudo prospectivo com 49 primigestas, incluídas no estudo na 18ª semana, sendo coletada a amostra sanguínea para a realização das dosagens séricas, realizadas pelo método de quimioluminescência (alfa-fetoproteína, gonadotrofina coriônica humana e óxido nítrico) e radioimunoensaio (peptídio atrial natriurético). O Doppler das artérias uterinas foi realizado entre 24-26 semanas, determinando a presença ou ausência de incisura na onda de velocidade de fluxo. Na análise estatística utilizou-se o teste de Mann-Whitney, para amostras não-paramétricas, e o teste exato de Fisher, para parâmetros qualitativos. RESULTADOS: Os valores de sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo foram, respectivamente, de 8,3%, 97,0%, 50,0% e 74,4% para a alfa-fetoproteína; 8,3%, 87,9%, 20,0% e 72,5% para a gonadotrofina coriônica humana; 16,7%, 97,0%, 33,3% e 76,2% para o peptídio atrial natriurético; e 16,7%, 93,9%, 50,0% e 75,6% para o óxido nítrico. A sensibilidade do Doppler foi de 75,0%, especificidade de 63,6%, valor preditivo positivo de 57,1% e valor preditivo negativo de 87,5%. CONCLUSÃO: O Doppler das artérias uterinas é melhor preditor de complicações da gestação quando comparado a alguns marcadores séricos em populações de baixo risco.