Altered Intervessel Distances in Right and Double Aortic Arch Anomalies on the Fetal Echocardiography Three-Vessel View

Background: The main aim of this study is to increase the recognizability of aortic arch anomalies during fetal echocardiographic examination. To evaluate intervessel distances in the three-vessel view in fetuses with isolated right or double aortic arch (DAA) anomalies during fetal echocardiography. Methods: This retrospective study included six fetuses examined between 19+0 and 21+0 weeks of gestation, with isolated right or DAA anomalies confirmed postnatally. Five fetuses had an isolated right aortic arch (RAA) anomaly, while one had an isolated DAA anomaly. Diameters of the main pulmonary artery (PA) and ascending aorta (Ao) were measured from the three-vessel view. Additionally, intervessel distances between the main PA–Ao, the Ao and superior vena cava (Ao–SVC), and the main PA–SVC were assessed. The standard deviation (SD) values were assessed using nomograms appropriate for gestational age. Results: The diameters of the PA and Ao were not significantly different from those in the normal population in any of the fetuses. In five of the six fetuses, the PA–Ao distance exceeded +3 SD, indicating an increase compared with fetuses without congenital heart defects. Additionally, the PA–SVC distance exceeded +3 SD in four fetuses, indicating a marked increase compared to fetuses without congenital heart anomalies. In contrast, the Ao–SVC distance was below –3 SD in only two fetuses, indicating a decrease, while no significant deviation was observed in the remaining four cases. Conclusions: In fetal echocardiography, isolated right or DAA anomalies can lead to altered intervessel distances on the three-vessel view. Notably, increases in the PA–Ao and PA–SVC distances were observed.