Aberrant Subclavian Artery: Etiology, Pathogenesis, Classification, Diagnosis, and Treatment

Aberrant right subclavian artery (ARPA) is the most common aortic arch anomaly, occurring in approximately 0.5-2% of the population. The vast majority of cases involve the aberrant right subclavianartery (arteria lusoria). The anomaly can be detected at any age, but is more commonly diagnosed either in childhood in the presence of symptoms or incidentally in adults on imaging studies.

Etiology

ARPA is the result of abnormal embryologic development of the 4th and 7th interaortic arches. The main cause is the preservation of the right 7th interaortic arch with regression of the right 4th arch, resulting in the right subclavian artery branching off the distal aorta, most often after the left subclavian artery, and passing behind the esophagus.

Risk Factors:

• Genetic abnormalities (e.g., 22q11.2 deletion);
• Syndromes with vascular malformation (Di Giorgi, Turner);
• It is often combined with congenital heart defects (tetrada Fallo, transposition of the main vessels);
• Hereditary predisposition is possible, especially when a similar anomaly is present in first-degree relatives.

Pathogenesis

An aberrant right subclavian artery can cause compression of nearby structures.

1. The artery causes compression of the esophagus → dysphagia.
2. In severe tracheal compression → respiratory symptoms (cough, dyspnea, stridor).
3. In rare cases, arterial ring formation (especially in the presence of a persistent right aortic arch and ductus arteriosus).
4. Aneurysmal dilation of the aberrant vessel (Kommerel’s diverticulum) → risk of rupture or thrombosis.

Classification

Clinical manifestations

Most adult patients are asymptomatic with ARPA. Symptomatology is more common in children, especially with combined anomalies.

Major manifestations:

• Dysphagia (strained swallowing, more often of solid food) is the main symptom in adults;
• Dyspnea, coughing, wheezing – with tracheal compression;
• Recurrent respiratory tract infections – in children;
• Chest pain, hoarseness, Gorner’s syndrome – in case of compression of neighboring neurovascular structures;
• Symptoms may increase with aneurysmal dilatation of the vessel.

Diagnosis

The diagnostic approach depends on the severity of symptoms and the presence of associated anomalies. Modern methods allow visualization of the anomaly with high accuracy.

• CT angiography (gold standard). Visualization of the arch anatomy, confirmation of aberrancy, assessment of compression.
• MR angiography. An alternative to CT for contraindications to iodine.
• Esophagography with barium. Indicated for dysphagia. Characteristic deformation of the posterior wall of the esophagus.
• Fibrobronchoscopy. For respiratory symptoms. Diagnosis of tracheal compression.
• Echocardiogram. Evaluation of associated cardiac malformations. Visualization of the anomalous artery as well as evaluation of blood flow.

Treatment of an aberrant subclavian artery

Conservative treatment

• Eliminating factors that exacerbate dysphagia (e.g., hard or dry food);
• Condition monitoring with imaging in asymptomatic course;
• In the presence of esophagospasm or esophageal inflammation may be used:
  • Prokinetics (high level obstruction, e.g., Commerel’s diverticulum with marked compression, must be ruled out before prescribing);
  • Proton pump inhibitors (if concomitant gastroesophageal reflux or esophagitis is present or suspected).

Surgical treatment

Indications:

• Symptomatic dysphagia or respiratory obstruction;
• Aneurysm of Commerel’s diverticulum;
• Combination with other heart defects requiring correction.

Methods:

Ligation and reimplantation of the artery into the right common carotid artery or brachial trunk (via supraclavicular access or lateral thoracotomy).

Resection of Kommerel’s diverticulum:

• Removal of the aneurysmal segment, often combined with reimplantation of the artery;
• Preferably via thoracotomy;
• In severe calcinosis/thrombosis of Kommerel’s diverticulum in the elderly: stent-graft or hybrid approaches are preferred.

Hybrid procedures: use of stent grafts with prior switch of the aberrant subclavian artery to the carotid artery.