Ácido Acetilsalicílico na prevenção de pré-eclâmpsia após determinação do ponto de corte utilizando critérios clínicos e biofísicos

Abstract

Introduction: Hypertensive diseases in pregnancy account for the largest share of maternal and perinatal morbidity and mortality in Brazil. The pathophysiology of preeclampsia (PE) involves numerous maternal and placental mechanisms. Several meta-analyzes have already shown that low doses of aspirin (ASA) in women at high risk for PE initiated before 16 weeks of gestation considerably reduce its prevalence, especially preterm PE. Algorithms for selecting the group that benefits from this measure have become promising, using clinical, biophysical and biochemical data; the last one little used in our country and unavailable in public health services. It is imperative that these algorithms be tested in different populations. Objectives: To determine the cutoff point for PE prediction, using the FMF (Fetal Medicine Foundation) algorithm without the information of biochemical markers, in a Brazilian population and to verify if the AAS modifies the endothelial function. Methodology: Randomized clinical trial with the inclusion of 277 nulliparous women. The participants were evaluated in all gestational trimesters with Doppler US of uterine arteries and flow-mediated dilation in the brachial artery. Between 11 and 14 weeks they were randomized to receive ASA at a dose of 100mg / day or placebo. The risk calculation was used without information from the biochemical data (PAPP-A and PlGF). The Mann-Whitney test was used to compare the variables age, weight, height, BMI and mean IP of the uterine arteries. Fisher's exact test and the chi- square test were used to verify the existence of an association between risk and PE. A significance level of 5% was adopted. The ROC Curve was used to determine the best cutoff point between the various sensitivities and specificities found for the different risks. Results: The anthropometric variables were similar between the groups that took AAS and placebo. Flow-mediated dilation showed no difference between groups during pregnancy. The evaluation of endothelial function did not present itself as a good screening method for pre-eclampsia alone or in association with other maternal criteria. The cutoff point found was 1 in 155 chances. The reduction in total pre-eclampsia by using ASA 100mg / day of 36.3% (prevalence of PE in the group above the cutoff point was 19% using ASA and 12.1% using placebo). Conclusions: ASA at a dose of 100mg / d does not modify the endothelial function assessed by flow-mediated dilation in the brachial artery during the pregnancy of nulliparous women. The cut-off point defined for Pre-eclampsia was 1: 155 with 80% sensitivity, 57.5% specificity, 19.1% positive predictive value and 95% negative predictive value, selecting patients who will benefit from ASA.