Assessment of Right Ventricular Endocardial Fibroelastosis in Fetuses with Critical Pulmonary Stenosis and Pulmonary Atresia with Intact Ventricular Septum

Background Systematic assessment of right ventricular (RV) endocardial fibroelastosis (EFE) in the fetus with critical pulmonary stenosis and pulmonary atresia with intact ventricular septum (CPS/PA-IVS) has not been reported. The implications of RV EFE for circulatory outcomes with or without fetal cardiac intervention (FCI) have also not been demonstrated. Methods The fetal echocardiographic data from July 2018 to January 2021 in a single-center institution were collected. Three reviewers independently graded EFE according to the presence and extent of endocardial echogenicity. The associations among EFE severity, anatomic variables, and postnatal outcomes were analyzed. Results 81 cases with RV EFE were identified. By consensus, EFE severity was assessed as grade 1 (“mild”; n=66, 81.48%), grade 2 (“moderate”; n=11, 13.58%), and grade 3 (“severe”; n=4, 4.94%). RV sphericity values were greater in grade 2 and 3 EFE groups compared to the grade 1 EFE group, implying more severe noncompliance and worse diastolic function. 10/81(12.35%) fetuses underwent FCI. At the latest available follow-up, 59/81 (72.84%) patients had achieved biventricular circulation. Furthermore, 9/59 (15.25%)—four with grade 1 EFE, three with grade 2, and two with grade 3—had undergone FCI, whereas the other 50/59 (84.75%)—who all had grade 1 EFE—had not. Conclusions For the first time in CPS/PA-IVS, RV EFE was graded and the potential of FCI to improve the prognosis of non-mild RV EFE patients was revealed. Non-mild RV EFE was suggested to be a putative indicator of FCI. Graphic Abstract