Papel do Doppler do ducto venoso na restrição de crescimento intrauterino / Ductus venosus Doppler assessment in intrauterine growth restriction

Objetivo: O crescimento intrauterino restrito (CIUR) por insuficiência placentária persiste como grande desafio obstétrico. A interrupção da gestação representa a única estratégia de condução e baseia-se na predição de desfechos adversos. O Doppler tem valor reconhecido na avaliação seriada das alterações circulatórias nesses fetos, em geral sequenciais e proporcionais à gravidade do insulto hipóxico. Este estudo objetiva revisar as evidências do papel do Doppler de ducto venoso (DV) na predição de morbimortalidade perinatal em gestações complicadas por CIUR placentário grave e precoce. Métodos: Realizou-se revisão narrativa, com busca de artigos publicados nos últimos 10 anos nas bases Medline/PubMed, Lilacs e Scielo, sendo encontradas 132 referências. Pesquisas com animais e gestações múltiplas foram excluídas. Dos 115 artigos selecionados, 34 foram excluídos por inadequação ao tema. A revisão baseou-se nas demais 81 referências, além de trabalhos de reconhecida relevância no tema. Resultados: Estudos demonstram evidência consistente do papel do Doppler de DV na avaliação de fetos com CIUR, com bom valor preditivo para acidemia fetal e desfecho perinatal adverso. As principais estratégias de monitorização se baseiam na combinação do Doppler de vasos arteriais/venosos e parâmetros biofísicos, mas o Doppler de DV seria o melhor parâmetro isolado para predição de comprometimento fetal grave. Conclusão: A incorporação do Doppler de DV na monitorização de fetos com CIUR grave e precoce é capaz de predizer desfechos perinatais críticos. A avaliação de múltiplos vasos fetais parece aumentar a acurácia, porém não há evidência para embasar a definição de protocolos para o manejo clínico.(AU)

Objective: Intrauterine growth restriction (IUGR) due to early onset placental insufficiency remains to be a great challenge in obstetrical practice. Delivery is still the only available strategy of management, and timing such intervention depends on prediction of adverse outcomes. Dopplervelocimetry studies have recognized value in the evaluation of the sequential hemodynamic changes that are stablished in the arterial and venous circulation of these fetuses, which correlate with the severity of hypoxemic insult. This study aims to review evidence on ductus venosus (DV) Doppler`s role as a predictor of perinatal outcome in pregnancies complicated by severe early onset IUGR. Methods: A Medline/PubMed, Lilacs and Scielo search was performed to identify original articles and systematic reviews published in the last 10 years. Eighty-one references were included in this review, in addition to other papers of recognized relevance in the subject. Results: Studies demonstrate consistent evidence on DV Doppler`s role in the longitudinal evaluation of IUGR fetuses, with adequate predictive value for fetal acidemia and adverse outcome. Monitoring strategies are usually based on a combination of arterial and venous Doppler assessment, in addition to biophysical parameters, but DV Doppler seems to be the best single parameter for prediction of severe fetal compromise. Conclusion: Monitoring of fetuses with severe early-onset IUGR through DV Doppler is able to predict critical perinatal outcomes. Evaluation of multiple fetal vessels seems to increase accuracy of prediction, but to this moment there is not enough evidence to recommend protocols of management.(AU)

Gender-specific differences in fetal cardiac troponin T in pregnancies complicated by placental insufficiency.

BACKGROUND: Placental insufficiency and fetal growth restriction may lead to fetal hypoxia and acidemia, which result in fetal cardiac injury. OBJECTIVE: The goal of this study was to compare the levels of fetal cardiac troponin T (cTnT) at birth and fetal Doppler parameters according to fetal gender in pregnancies complicated by placental insufficiency before 34 weeks' gestation. METHODS: Between March 2007 and November 2010, singleton pregnancies with placental insufficiency characterized by abnormal umbilical artery Doppler results were prospectively studied. All the patients delivered by cesarean section, and Doppler examinations were performed up to 48 hours before birth. Immediately after delivery, umbilical artery blood samples were obtained for fetal cTnT measurements. RESULTS: Fifty high-risk pregnant women met the study criteria. The study groups were as follows: group 1 consisted of 23 male fetuses (46%) and group 2 consisted of 27 female fetuses (54%). cTnT levels were significantly higher in the group of male fetuses (median, 0.14; range, 0.01-0.85) compared with the group of female fetuses (median, 0.05; range, 0.01-0.27) (P = 0.039). In the group of male fetuses, Doppler results of the ductus venosus assessment revealed values of pulsatility index for veins ≥1.0 in 15 male fetuses (65.2%) and 9 female fetuses (33.3%) (P = 0.032). CONCLUSIONS: Fetal gender was associated with cTnT level at birth in pregnancies complicated by placental insufficiency before 34 weeks' gestation, although the Doppler findings did not support gender differences. The fetal cardiac compromise and cardiac injury may be influenced by fetal gender, suggesting differences in the cardiovascular response to fetal hypoxia.