Fetal double aortic arch: prenatal sonographic and postnatal computed tomography angiography features, associated abnormalities and clinical outcomes

Abstract

Background: Fetal double aortic arch (DAA) malformation is a rare congenital heart disease with few reported cases in the literature. We aimed to investigate the characteristics of prenatal ultrasound and postnatal computed tomography angiography (CTA) of DAA and to describe the associated anomalies and clinical outcomes to improve prenatal diagnosis and assist in perinatal management.

Methods: The obstetric ultrasound imaging databases of seven tertiary referral centers were reviewed retrospectively to identify fetuses with a prenatal diagnosis of DAA between January 2013 and December 2018. Ultrasonographic findings, associated anomalies, genetic abnormalities, postnatal CTA images, and long-term postnatal outcomes were evaluated.

Results: A total of 36 cases out of 40 prenatally diagnosed DAA fetuses were confirmed by postnatal diagnosis (fetal autopsy, CTA, and surgery). In this cohort of 36 confirmed cases, 24 (67%) were isolated anomalies, while 12 (33%) were associated with intracardiac or extracardiac anomalies, and 2 (6%) had a 22q11.2 chromosome deletion. Among nine cases of pregnancy termination with a fetal autopsy, 7 had other abnormalities. Among the remaining 27 live births, 16 (59%) were asymptomatic and 11 (41%) received surgical treatment due to tracheal or esophageal compression symptoms, all with satisfactory outcomes. Prenatal echocardiography showed that DAA was mainly characterized by a bifurcation of the ascending aorta into the right and left aortic arch and the formation of a complete O-shaped vascular ring around the trachea on the three-vessel tracheal view. A variant in the aortic arch branching pattern was found for the first time. The airway obstruction, branching pattern, and atretic arch of DAA were clearly shown by postnatal CTA.

Conclusions: Fetal DAA has unique features on prenatal echocardiography and postnatal CTA, and systematic prenatal examination and timely postnatal CTA evaluation are required. A certain proportion of intracardiac and extracardiac abnormalities are associated with DAA, but the probability of chromosome abnormalities is low, especially for isolated DAA.The clinical outcomes of isolated DAA are favorable, even if surgery is performed due to symptoms. Determining whether other malformations or chromosomal anomalies exist is crucial for prognosis evaluation and prenatal counseling.

Keywords: Double aortic arch; fetal echocardiography; prenatal diagnosis; prenatal ultrasound; vascular ring.

Fig. 1

Fetal anatomical pathology after termination of pregnancy. a The right and left aortic arches both arise from the ascending aorta. The left aortic arch gives rise to the LCCA and LSA, and the right aortic arch gives rise to the RCCA and RSA. The left ductus arteriosus connects to descending aorta. b After the trachea is cut off, the left and right arches form a complete vascular ring, which is connected to the descending aorta. (AAO: ascending aorta; R: right aortic arch; L: left aortic arch; RCCA: right common carotid artery; RSA: right subclavian artery; LCCA: left common carotid artery; LSA: left subclavian artery; PA: pulmonary artery DA: ductus arteriosus; DAO: descending aorta; T: trachea)

Fig. 2

Bifurcation of the ascending aorta and a complete vascular ring of the DAA on fetal echocardiography. a Left ventricular outflow tract view: The distal ascending aorta bifurcation is confirmed as the right arch and left arch. b Three-vessel tracheal view: A bifurcation of the ascending aorta into the right aortic arch and left aortic arch to form a complete O-shaped ring encircling the trachea, together with a number 9 configuration connecting with the left-sided ductus arteriosus. Both aortic arches demonstrate antegrade blood flow (AO or AAO: ascending aorta; R: right aortic arch; L: left aortic arch; PA: pulmonary artery; DA: ductus arteriosus; T: trachea)

Fig. 3

DAA with distal left aortic arch atresia on fetal echocardiography. a Nonstandard three-vessel tracheal view of gray-scale imaging: The vascular echo at the distal end of the left aortic arch is interrupted and replaced by a fibrous cord (arrowhead). b. Nonstandard three-vessel tracheal view of color Doppler imaging shows the interruption of color flow at the distal end of the left aortic arch(arrowhead) and an incomplete vascular ring(L-ARCH: left aortic arch; DAO: descending aorta; T: trachea)

Fig. 4

Branching pattern of DAA on fetal echocardiography. a Sagittal view of the right aortic arch: The dominant right arch gives rise to the RCCA and RSA. b Sagittal view of the left aortic arch: The small left aortic arch gives rise to the LCCA and LSA. c The coronal view of the aortic arch shows the symmetric appearance of the common carotid artery and subclavian artery originating from the ipsilateral aortic arch simultaneously(R-ARCH: right aortic arch; L-ARCH: left aortic arch; RCCA: right common carotid artery; RSA: right subclavian artery; LCCA: left common carotid artery; LSA: left subclavian artery)

Fig. 5

Branching pattern variant of DAA on fetal echocardiography. a Sagittal view of the left aortic arch: One branch can be viewed from the left aortic arch (H: heart, 1: left common carotid artery). Sagittal view of the right aortic arch: Three branches can be viewed from the right aortic arch (H: heart, 1: right common carotid artery, 2: right subclavian artery, 3: left subclavian artery, L-ARCH: left aortic arch; R-ARCH: right aortic arch; DAO: descending aorta)

Fig. 6

Three-dimensional color-rendered image with spatiotemporal image correlation of DAA: The left aortic arch and the dominant right aortic arch develop a complete vascular loop, join the left ductus arteriosus, and converge into the descending aorta together. Symmetrical initial parts of the two branches can probably be observed on each arch. (R-ARCH: right aortic arch; L-ARCH: left aortic arch; RCCA: right common carotid artery; RSA: right subclavian artery; LCCA: left common carotid artery; LSA: left subclavian artery; DA: ductus arteriosus; DAO: descending aorta)

Fig. 7

Postnatally confirmed diagnosis of DAA by multidetector-row CTA with volume-rendering processing. a Transaxial view: The ascending aorta divides into two arches surrounding the trachea and esophagus. b Left view of volume-rendered image: The spatial structure mimics that in Fig. 6, but the branches (the LCCA and the LSA originating from the left arch, the RCCA and the RSA originating from the right arch) and the arches surrounding of the trachea and esophagus appear clearer. c The proximity of the posteroinferiorly distorted left subclavian artery (arrow) and descending aortic diverticulum (*) suggests a possible fibrous connection (arrowhead) between the two structures and demonstrates a double aortic arch with an atretic left aortic arch distal to the origin of the left subclavian artery. d. A trachea compressed by the vascular ring is shown (arrowhead) (AAO: ascending aorta; R or R-ARCH: right aortic arch; L or L-ARCH: left aortic arch; RCCA: right common carotid artery; RSA: right subclavian artery; LCCA: left common carotid artery; LSA: left subclavian artery; DAO: descending aorta; T: trachea; LPB: left principal bronchus, RPB: right principal bronchus)