Evaluation of the predictive value of placental vascularisation indices derived from 3-Dimensional power Doppler whole placental volume scanning for prediction of pre-eclampsia: A systematic review and meta-analysis

Pre-eclampsia remains a leading cause of maternal and fetal morbidity and mortality. This systematic review aims to evaluate the ability of placental vascularisation indices (PVIs) derived from 3D power Doppler whole placental volume scanning to predict early, late and any-onset pre-eclampsia (PE). The following databases were searched: MEDLINE, EMBASE and Web of Science. Studies selected for inclusion measured PVIs: Vascularisation Index (%) (VI) and/or Flow Index (FI) and/or Vascularisation Flow Index (VFI) derived from 3D power Doppler whole placental volume scanning via Virtual Organ Computer-aided Analysis (VOCAL) technique prior to diagnosis of PE. A total of 667 records were screened with five eligible studies included. A narrative review of all studies was undertaken and three studies with sufficient data were included in a meta-analysis. This review, the first of its kind to evaluate the predictive value of PVIs for PE, reports significantly lower first trimester PVIs across a range of studies in women who develop PE. Mean differences in vascularisation indices in PE and non-PE pregnancies were: VI -2.93% (95% CI -5.84,-0.01), FR -2.83 (95% CI -3.97,-1.69) and VFI -0.93 (95% CI -1.6,-0.25), respectively. While only two studies reported sensitivity and specificity data, VI and VFI most accurately predicted early onset PE, and VFI predicted PE in high risk women. Further research is required to validate these findings in different study populations and to examine the performance of PVIs within combined screening models for PE.