OS074. Brachial artery flow-mediated dilatation as a predictor of pre-eclampsia in the first trimester of pregnancy

Abstract

Increased vascular reactivity secondary to endothelial injury has been reported to be involved in the pathogenesis of pre-eclampsia (PE). However, whether these observations of vascular activity are the result or the cause of PE is still not fully understood. Some studies have shown that pregnant women who subsequently suffer from PE have an impaired flow-mediated dilatation in the brachial artery at the beginning of the second half of pregnancy. However this parameter has not been tested as a first trimester predictor of PE. To investigate the role of maternal brachial artery reactivity during the first trimester of pregnancy (11-14 weeks) for the prediction of PE. Prospective study with singleton pregnancies examined at 11-14 weeks of gestation, presenting consecutively for antenatal care in a tertiary Brazilian hospital. Maternal endothelial dysfunction was assessed by flow-mediated dilatation (FMD) of the brachial artery. FMD was assessed in 550 pregnant women by the same examiner. Obstetric and perinatal outcomes were available in 506 patients (92%). A total of 19 cases were excluded, because 6 miscarried, 12 presented isolated fetal growth restriction (FGR) and 1 was considered an "outlier" because of a significant inflammatory medical co-morbidity. The main outcome was PE based on the ISSHP classification, and we considered early-onset PE when delivery occurred before 34 weeks and late-onset PE when delivery occurred after 34 weeks. In a total of 487 patients, 31 cases developed PE (6.3%), with 9 cases (1.8%) of early-PE and 22 cases (4.5%) of late-PE. The mean gestational age of the study was 12 weeks (range 11-14 weeks).The diameter of the brachial artery at rest was similar between control and PE groups (2.83mm and 2.93mm; p = 0.60) and the resistance and pulsatility index measurements also showed no significant differences among these groups. The mean FMD was 7.4 ± 8.2% in the control group and 7.3 ± 8.2% in the PE group. Logistic regression analysis determined that FDM was not a predictor of PE (OR=0.99, CI 95% 0.94-1.04; p=0.90). Dividing the cases of PE in early and late-onset, it was also observed that the mean diameter of the brachial artery at rest was similar among these groups, and that after the shear stress test the diameter was not significantly different in patients who developed early-PE. Maternal brachial artery reactivity assessed by FMD in the first trimester of pregnancy is not a predictor of PE.