Placental Microvascular Architecture Imaging in Normal and Congenital Heart Disease Pregnancies

To evaluate the placental vascular architecture using MV Flow™ imaging for analyzing vascular distribution per region of biological tissue in isolated congenital heart diseases (CHD), CHD associated with extracardiac malformations (EXM) and normal pregnancies, and to explore the relationship of fetal Doppler flow parameters and growth to placental perfusion in these conditions.

Placental microvascular structure was assessed using MV-Flow™ in a total of 227 normal fetuses and 139 with CHD; fetuses with gestational age ranging from 11 to 41 weeks were included. Placental vascular indices (VI^MV %) was acquired at three different segments of each placenta (upper, middle, and lower regions). Doppler pulsatility indices of fetal umbilical artery (UA), middle cerebral artery (MCA), ductus venosus (DV), uterine artery (UtA), and cerebroplacental ratio were measured in both normal and CHD groups. The CHD group was divided into two subgroup based on whether it is associated with EXM.

Compared to the control group, the CHD with EXM group exhibited a significantly lower VI^MV % for the upper, middle, and lower regions of the placenta (P = .005; P = .018; P = .039, respectively). In the total CHD group, VI^MV % decreased in the middle segment of placenta in the 2nd trimester compared to the control group. But the VI^MV % of upper and middle segments decreased in the 3rd trimester. Both subgroups, EXM and isolated CHD, showed similar distribution of gestational weeks. Doppler vascular indices were significantly different compared to normal in the total CHD group for UA-pulse index (PI), DV-PI, right UtA-PI, and left UtA-PI, with similar differences from normal for the CHD with EXM group. DV-PI was the only significantly different Doppler vascular parameter for the isolated CHD group compared to normal.

For the first time, MV-Flow™ imaging demonstrated reduced placental vascularity in fetuses with CHD and ECM and in fetuses with isolated CHD in the 3rd trimester of pregnancy. Application of MV-Flow™ as part of serial fetal echocardiographic surveillance in cases of CHD may allow for better understanding of the development of placental abnormalities.