P05.04: Placental histology and sFlt‐1/PlGF in pregnancies complicated by hypertensive disorders

Abstract

Redline classification correlates the histology of placental lesions with the pathogenesis of the correspondent obstetric disorder. Our work evaluates the correlation between hypertensive disorders of pregnancy (HDP), placental histology and circulating angiogenic factors (sFlt-1, PlGF). In this observational study, 30 pregnant patients affected by HDP (gestational hypertension, pre-eclampsia) were recruited: 20 HDP with intrauterine growth restriction (HDP-IUGR) and 10 HDP with an appropriate for gestational age fetus (HDP-AGAf); 16 controls with uneventful pregnancies were also included. Diagnosis of HDP was based on Canadian Guidelines (SOGC 2014). Diagnosis of IUGR was made for fetuses with abdominal circumference (AC) < 10th percentile or with AC measure deflecting at least 40 percentiles. The patients underwent a blood sampling for the dosage of sFlt-1 and PlGF. Placentas were analysed for histological examination, executed in blind by a dedicated pathologist, using Redline classification. HDP-IUGR shows vascular lesions on the placental maternal side in 95% of cases, significantly more than HDP-AGA (p=0.03) and also than controls (p<0.001). These lesions result from early placental oxidative stress, due to incomplete spiral arteries remodelling; they include developmental anomalies (decidual arteriopathy 50%, villous hypoplasia 40%) and obstructive vascular lesions (syncytial knots 65%, placental infarcts 40%). HDP-AGA predominantly shows vascular lesions on the placental fetal side in 70% of cases. These lesions are represented for 70% by developmental anomalies, especially hyper-ramification and villous immaturity, indicating late placental oxidative stress. sFlt-1/PlGF ratio correlates with vascular lesions on the placental maternal side, typical of HDP-IUGR group. Placental histology and angiogenic markers correlate with the severity of placental damage and with the different fetoplacental phenotypes of HDP, supporting investigations about their pathogenesis.