Foramen ovale flap aneurysm in fetuses associated with and without heart defects: Prenatal diagnosis, imaging, in‐utero hemodynamics, pregnancy, and postnatal outcomes

BACKGROUND: Isolated redundant foramen ovale flap aneurysm (RFOA) in the absence of restrictive foramen ovale is believed to be a cause for pseudocoarctation of aorta since the impediment of blood flow to the left heart can be severe, resembling the picture of left ventricular hypoplasia with retrograde aortic flow. The primary objective of the study is to find whether RFOA is always a benign lesion. The main focus of the study is to share my experience in particular on fetuses having redundant foramen ovale flap aneurysm developing into coarctation of aorta and to study the associated factors. METHODS: Retrospective study (January 2020 to June 2023). All fetuses with RFOA associated with and without congenital heart defects were included. Fetuses with restrictive foramen ovale and RFOA with single ventricle hearts were excluded. The imaging, in-utero hemodynamics, pregnancy, and postnatal outcomes with at least 3 months follow-up were presented. RESULTS: During the study period, a total of 1499 fetal echocardiography were performed. Twenty-two fetuses with RFOA were included. Fourteen fetuses had isolated RFOA and eight had associated abnormalities [extracardiac (n = 5); intracardiac (n = 2), Both (n = 1)]. Genetic evaluation were performed only in fetuses with associated defects were normal. Postnatally all isolated RFOA fetuses had no aortic arch obstruction. Fetuses with associated aberrant right subclavian artery, isolated left superior vena cava, absent ductus venosus and ventricular septal defects developed aortic arch obstruction after birth. RFOA causes smallish left ventricle in fetuses with tetralogy of Fallot which recovered to normal size postnatally. CONCLUSION: Isolated RFOA can be benign, however, if it is associated with cardiac or extracardiac anomalies predominantly resulted in aortic arch obstruction. Though it is a cause for pseudocoarctation of aorta, through postnatal reassessment of aortic arch is mandatory. Careful search for intracardiac and systemic venous anomalies is recommended. It created confusion regarding adequacy of left ventricle when associated with congenital heart defects.