Redundancy of foramen ovale flap may mimic fetal aortic coarctation

Abstract

Objectives To assess the relationship between presence of a redundant foramen ovale flap (RFOF), in the absence of a clearly restrictive foramen ovale, and ventricular disproportion, in three groups of fetuses: (1) those with a final diagnosis of aortic coarctation (CoA); (2) those referred for suspicion of ventricular disproportion and/or CoA which did not develop CoA postnatally; and (3) normal fetuses. Methods This was a retrospective study including 73 fetuses: 12 with a final diagnosis of isolated CoA; 30 referred for suspicion of ventricular disproportion and/or CoA, which did not develop CoA postnatally; and 31 normal fetuses. Four‐dimensional volume datasets and clips were assessed offline. Maximum diameters of the FOF (FOFD), left atrium (LAD), right atrium, left and right ventricles and, when available, aortic isthmus, were measured, as were areas of the FOF (FOFA), left atrium (LAA) and right atrium. The left/right ratios for all segments of the heart, as well as the FOFD/LAD ratio and FOFA/LAA ratio, were calculated. Regression analysis was performed to assess the relationship between RFOF and ventricular disproportion and means were compared by ANOVA. Results Repeatability was fair, with all variables having an intraclass correlation coefficient ≥ 83%. In the pooled group of fetuses with no CoA found at birth (normal fetuses plus those with ventricular disproportion (n = 61)), there was a significant linear correlation between redundancy of the FOF and degree of ventricular disproportion (P < 0.01 and P < 0.05 for diameter and area ratios, respectively). Categorizing the FOF redundancy, FOFD/LAD ratio ≥ 0.65 was significantly associated with ventricular disproportion (P = 0.006). Based on the degree of FOF prominence, we described four categories of redundancy, ranging from no redundancy/ventricular disproportion (Stage 0) to severe redundancy/ventricular disproportion with transient obstruction of the foramen ovale or mitral orifice (Stage III). Comparing cases without neonatal evidence of coarctation but FOFD/LAD ratio ≥ 0.65 vs those with neonatal evidence of coarctation, there was no statistically significant difference in the degree of ventricular disproportion or in the Z‐score of the aortic isthmus maximum diameter. Conclusions This study demonstrates that: (1) there is an association between RFOF and ventricular disproportion, independent of the association with a restrictive foramen ovale, and (2) the presence of a RFOF may mimic CoA. In fact, it causes both ventricular disproportion and a significant reduction in the diameter of the aortic isthmus, associated in some cases also with reversed isthmic flow. Future prospective studies are needed to evaluate whether focusing the sonologist's attention on the appearance of the foramen ovale may reduce the rate of false‐positive diagnosis of CoA. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Application of a Global Multiparameter Scoring System for the Prenatal Prediction of Coarctation of the Aorta

“…This reduction in the left ventricular preload would produce a cardiac asymmetry with right dominance, simulating what occurs with CoAo, thus being a possible source of false positives for this condition. This hypothesis is similar to that recently proposed by Vena et al [40], where they also observed that RFOP can lead to cardiac asymmetry with right dominance, mimicking what happens with CoAo. They postulated two events as the cause of this situation: a dynamic obstruction of the mitral inflow and an obstruction to blood flow coming from the ductus venosus to the right atrium and left atrium.…”

“…Therefore, in this study, the reference for calculating the Z-score values was always the same, namely gestational age. We also recorded the subjective assessment of the appearance of the aortic arch (diffuse hypoplasia of the entire aortic arch from the ascending aorta to the isthmus or not, based on the impression of a narrowing of the whole aortic arch towards the isthmus), the persistence of the left superior vena cava (PLSVC), the presence of a infolding of the posterior wall of the aortic arch after the origin of the left subclavian artery (contraductal shelf), and the appearance of the foramen ovale (FO) (redundant or not, considered as redundant when it prolapses into the left atrium for more than 50% of the left atrial width, assessed subjectively) [40]. Additionally, functional parameters were registered including transaortic peak velocity and blood flow evaluation at the aortic arch with color Doppler (antegrade filling, mixed pattern with antegrade and retrograde ductal-dependent flows or reversed filling from the ductus) and FO (right-to-left, left-to-right or bidirectional).…”

Comparisons of foramen ovale flap in the fetuses with true and false positive diagnosis of coarctation of the aorta

“…A recently published study showed that the presence of RFOF may simulate coarctation of the aorta (CoA) (6). CoA is one of the most common congenital heart diseases in neonates and children, and may require immediate surgery after birth.…”

“…False positive diagnosis of CoA can cause parental anxiety and may change delivery plans for prenatal care. Vena et al (6) demonstrated that RFOF determined ventricular asymmetry and reduced the diameter of the aortic isthmus (AOi). However, the difference in FOF prominence between fetuses with false positive and true positive CoA was not definite.…”

The wall and its gate: complexities of the atrial septum and foramen ovale in the fetal heart

“…Vena and colleagues, in the current issue of the Journal, focus attention on the relationship between redundancy of the flap valve of the foramen ovale and ventricular disproportion 4 . The authors found a strikingly similar signature of left ventricular appearance between fetuses which had coarctation of the aorta confirmed postnatally and those with redundancy of the flap valve of the foramen ovale, but with normal aortic arch and no coarctation.…”