G447(P) Right aortic arch in fetal screening. what should we do about it

Aims Since the introduction of the 3-vessel and trachea view at 20 week anomaly scans, referrals to paediatric cardiology for antenatally diagnosed aortic arch abnormalities have increased. Isolated right aortic arch (RAA) is rare (0.1% live births). One quarter of these are associated with vascular rings which can result in respiratory and feeding difficulties. We wished to determine the clinical and surgical outcomes of patients with RAA and how best to manage them. Methods All patients born from 1.1.08 to 31.07.18 were included who were diagnosed RAA, vascular ring, aberrant subclavian artery and Kommerell’s diverticulum on our database. Postnatal outcome and investigations performed were reviewed. Results 79 cases, including 16 (20.2%) where it was an isolated abnormality were included. 36 (45.5%) were associated with intracardiac anomalies and 26 (33%) were associated with both intracardiac and extracardiac anomalies. The commonest associated pathologies were Tetralogy of Fallot (26), ventricular septal defect (13), pulmonary atresia (9) and atrioventricular septal defect (8). 21.5% had genetic abnormalities including 22q11.2 microdeletion (6) and trisomy 21 (5). 70.8% had no symptoms attributable to RAA. Patients with isolated RAA but not those with associated anomalies underwent CT/MRI, bronchoscopy/CT bronchoscopy and barium swallow. 18 (22.7%) required surgical intervention, usually at less than 1 year of age. Of these, 11 had isolated vascular ring. Conclusion Only 18/79 children with RAA required surgical intervention, and 11 of these had isolated RAA. At the current time, the appropriate and agreed management protocol for this condition is not in place. Even the apparently straightforward re-implantation of an aberrant left subclavian artery is not a simple operation, nor is there good evidence for the benefit. Longer term follow up on a national scale is required to formulate the most appropriate approach to this diagnosis.