Right aortic arch and double arch assessed by prenatal echocardiography: a population-based study

Introduction of the three-vessel trachea view to the second trimester foetal anomaly screening programme increased detection of right (RAA) and double (DAA) aortic arch. Aim was to investigate incidence, associations, and medium-term outcome of RAA/DAA.

Retrospective, population-based, multicentre, observational study of foetuses diagnosed with RAA/DAA between 1 April 2015 and 31 March 2019. All cardiology units in England, Scotland and Wales participated. Foetuses with major congenital heart disease were excluded.

Overall, 1046 foetuses were diagnosed with RAA (n = 898, 85.9%) or DAA (n = 141, 13.5%), uncategorized in seven (0.6%). Estimated incidence of RAA and DAA was 17.98 and 4.58 per 10 000 pregnancies screened/year (0.23%). Nine hundred forty cases (89.9%) were isolated, with prenatal extracardiac anomaly (ECA) and/or minor cardiac difference in the remainder. Genetic results were abnormal in 80 of 1046 (7.6%): 22q11.2 microdeletion (n = 28, 35%). Prenatal ECAs increased the risk of genetic anomaly (risk ratio 3.39, 95% confidence interval 1.89-5.73, P < .0001). Nine hundred eighty six (94.3%) were liveborn, while five died postnatally from unrelated problems. Mean follow-up is 4.1 years (standard deviation 1.4), and symptoms of tracheoesophageal compression were found in 278 of 986 (28.2%). Vascular ring relief was performed in 234 of 986 liveborn (23.7%) with no deaths. There was variation in management pathways. Surgery was performed in 74.6% with DAA, 24.4% with RAA-left arterial duct (LAD)-aberrant left subclavian artery (ALSA); median age at surgery was 5.29 months [interquartile range (IQR): 2.99-11.26 months] and 12.62 months (IQR: 8.68-17.32 months), respectively (P < .0001).

Incidence of RAA/DAA is higher than previously reported. Genetic anomaly is identified in at least 7.6%, particularly in the presence of ECA. Liveborn with DAA have earlier and more surgical intervention compared to those with RAA-LAD-ALSA.