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

BACKGROUND AND AIMS: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.