Ultrasound Obstet Gynecol. 2020 Jun 23.
OBJECTIVE: The primary objective of this study is to assess whether foetuses with congenital heart disease (CHD) have smaller frontal brain areas than normal controls. Secondary objective is to evaluate whether there is any difference among CHD with different haemodynamics.
METHODS: Retrospective cross-sectional study, including 421 normal foetuses and 101 fetuses with isolated CHD. The study group was subdivided according to the CHD haemodynamics into the following subcategories: 1) Hypoplastic left heart syndrome (HLHS) and other forms of functionally univentricular heart defects; 2) Transposition of the Great Arteries; 3) conotruncal defects and other CHDs with large shunts; 4) right ventricular outflow tract obstruction, without a hypoplastic right ventricle; 5) left outflow tract obstruction; 6) others. The transventricular axial view of the fetal head was used as reference view, on which the Frontal Antero-Posterior Diameter (FAPD) and the Occipito-Frontal Diameter (OFD) were measured, assuming the former as representative of the frontal lobes' area. The FAPD/OFD ratio was then calculated (FAPD/OFD*100). These two variables (FAPD and FAPD/OFD Ratio) were then evaluated in the study and control group. Statistics included Kruskal-Wallis and Mann-Whitney U tests for two groups' comparison. Adjustment for gestational age both via multiple linear regression model and by using the a posteriori matching based on the propensity score was also employed.
RESULTS: In normal foetuses, FAPD showed a linear positive correlation with gestational age. In foetuses with CHD, the FAPD was shorter than in normal foetuses at all gestational ages, with the difference increasing after 30 gestational weeks. The FAPD/OFD Ratio was significantly lower in foetuses with CHD than in normal foetuses (p < 0.0001) at all gestational ages, with no differences among the various CHD categories, which all showed lower FAPD/OFD Ratios than normals (p < 0.0001).
CONCLUSIONS: Fetuses with CHD show a shorter FAPD and a lower FAPD/OFD than normal foetuses. This impaired growth of the frontal area of the brain seems to occur in all types of CHD, regardless of their haemodynamics. This article is protected by copyright. All rights reserved.
Keywords: Central Nervous System; cavum septi pellucidi; congenital heart disease; fetus; frontal lobe; ultrasound