Vascular Ring

A vascular ring is a group of congenital aortic arch and great vessel anomalies in which the trachea and oesophagus are encircled (complete rings) or compressed (incomplete rings or slings) by vascular structures. They account for under 1% of congenital heart disease.

Most occur in isolation, though associated cardiac lesions and 22q11.2 deletion are more frequent with right arch forms. Complete rings are the double aortic arch and the right arch with an aberrant left subclavian artery and left ligamentum arteriosum.

Incomplete rings include the pulmonary artery sling, innominate artery compression and the aberrant right subclavian artery.

Pathophysiology. The arch develops from paired embryonic arches. Persistence or regression of the wrong segments leaves vessels or the ligamentum arteriosum that wrap around the airway and oesophagus. Compression of the trachea causes stridor, wheeze and tracheomalacia.

Compression of the oesophagus causes dysphagia. Symptom severity depends on the tightness of the ring and on how long the compression has acted on the airway.

• Complete rings: biphasic stridor, wheeze, brassy cough, respiratory distress, apnoeic or cyanotic spells, dysphagia, vomiting, aspiration and failure to thrive. Symptoms usually appear within the first year. Neck extension relieves them.
• Right arch with aberrant left subclavian artery: frequently later onset, in childhood, with milder dysphagia and cough.
• Aberrant right subclavian artery: usually asymptomatic. Adults may report dysphagia.
• Examination: often normal. The arm pulses and blood pressures may differ with a subclavian anomaly.

Red flags.

• Apnoeic or cyanotic spells
• Stridor with feeding difficulty or failure to thrive
• Recurrent aspiration or chest infection
• Tracheal deviation or right arch on chest X-ray with respiratory symptoms
• Features of 22q11.2 deletion

• Chest X-ray: right arch, tracheal deviation or narrowing.
• Barium swallow: oesophageal indentation pattern distinguishes types (bilateral for a complete ring, posterior for an aberrant subclavian artery, anterior for a pulmonary artery sling).
• Echocardiography: arch sidedness, branching pattern and associated lesions.
• CT angiography with airway reconstruction: the definitive test. It shows the ring, any Kommerell diverticulum, and the airway.
• MRI: a radiation free alternative.
• Bronchoscopy: degree of tracheomalacia or tracheal rings.
• Genetic testing for 22q11.2 deletion when indicated.

Differential diagnosis.

• Primary tracheomalacia
• Subglottic stenosis
• Laryngomalacia
• Bronchiolitis or asthma
• Foreign body
• Oesophageal atresia repair stricture
• Gastro oesophageal reflux
• Mediastinal mass
• Achalasia

• Symptomatic complete ring: surgical division of the ring, division of the ligamentum arteriosum, and release of fibrous bands.
• Kommerell diverticulum: a large or enlarging diverticulum is resected with transfer of the subclavian artery.
• Residual tracheomalacia: aortopexy or tracheopexy.
• Pulmonary artery sling: reimplantation of the left pulmonary artery, with tracheoplasty for stenosis.
• Innominate artery compression: conservative in most; aortopexy for recurrent apnoea or severe compression.
• Aberrant right subclavian artery: no treatment when asymptomatic. Reimplantation into the right carotid artery or ascending aorta for troublesome dysphagia.
• 22q11.2 deletion: check calcium and lymphocyte subsets, and use irradiated blood products until T-cell function is shown to be adequate.

Special groups. Adults with a complete ring and symptoms are offered surgery; asymptomatic adults are observed with periodic imaging.

Monitoring. Review airway and feeding symptoms at 1, 3 and 6 months, then annually. Imaging or bronchoscopy for persistent symptoms. Echocardiography for associated cardiac lesions.

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