Double Aortic Arch

Double aortic arch is a complete vascular ring in which persistence of both embryonic fourth arches produces two aortic arches arising from the ascending aorta. They pass on either side of the trachea and oesophagus and join behind the oesophagus to form the descending aorta, usually on the left.

It is the most common symptomatic complete vascular ring, accounting for about half of rings. The right arch is dominant in about 70%, the left in about 20%, and the arches are balanced in the remainder. Most cases are isolated.

Associated cardiac lesions (tetralogy of Fallot, ventricular septal defect, transposition, coarctation) occur in a minority, and 22q11.2 deletion is a recognised association.

Pathophysiology. The ring compresses the trachea from the front and sides and the oesophagus from behind. Symptoms start early, usually within the first 6 months, and severity follows the tightness of the ring. Prolonged compression produces tracheomalacia, which can outlast the compression.

• Biphasic stridor, wheeze, brassy cough, respiratory distress, and apnoeic or cyanotic spells
• Dysphagia, feeding difficulty, vomiting, aspiration, failure to thrive
• Symptoms worse with feeding, crying or flexion of the neck, and relieved by neck extension
• Recurrent chest infections
• Examination: often normal, with equal pulses and blood pressures in the arms

Red flags.

• Stridor with feeding difficulty in an infant
• Apnoeic, cyanotic or reflex apnoeic episodes
• Recurrent aspiration
• Failure to thrive
• Hypocalcaemia, palatal anomalies or immune deficiency suggesting 22q11.2 deletion

• Chest X-ray: tracheal narrowing, midline trachea, and sometimes right arch features.
• Barium swallow: bilateral oesophageal indentations (posterior and lateral).
• Echocardiography: suprasternal views show two arches, and associated lesions are excluded.
• CT angiography with airway reconstruction: two arches from the ascending aorta, each with its own carotid and subclavian artery (symmetric four branch pattern), with the airway and oesophageal relationships.
• MRI: an alternative without radiation.
• Bronchoscopy: assesses the degree of tracheomalacia.
• Genetic testing: 22q11.2 deletion when there are cardiac lesions or other features.

Differential diagnosis.

• Right arch with aberrant left subclavian artery and left ligamentum arteriosum (also a complete ring)
• Pulmonary artery sling
• Innominate artery compression
• Primary tracheomalacia
• Subglottic stenosis
• Laryngomalacia
• Aberrant right subclavian artery
• Oesophageal stricture or reflux
• Foreign body

• Surgical division of the smaller (non-dominant) arch, at a site that preserves the carotid and subclavian branches, with division of the ligamentum arteriosum and release of the fibrous bands around the trachea and oesophagus. Approach is by thoracotomy on the side of the non-dominant arch, or thoracoscopically in suitable patients. Surgery is indicated for all symptomatic patients, and is usually advised for asymptomatic complete rings because symptoms can emerge later.
• Persistent tracheomalacia: aortopexy or tracheopexy.
• 22q11.2 deletion: check calcium and lymphocyte subsets before surgery, and use irradiated blood products until T-cell function is shown to be adequate.
• Operative mortality in isolated cases is low. Symptom resolution is gradual and residual airway symptoms may persist for months to years.

Special groups. Infants with severe tracheomalacia may need prolonged respiratory support after surgery.

Monitoring. Review airway and feeding symptoms at 1, 3 and 6 months and annually. CT or bronchoscopy when symptoms persist. Echocardiography for associated lesions.

Referral and escalation. Refer to a paediatric cardiothoracic centre. Urgent surgery for apnoeic or cyanotic spells or respiratory failure.