Arteria lusoria

Definition

• The arteria lusoria is an aberrant right subclavian artery that arises distally from the aortic arch, usually as the last branch, after the left subclavian artery.
• Instead of originating from the brachiocephalic trunk (normal anatomy), it arises directly from the aortic arch and passes behind the esophagus to reach the right upper limb.

Epidemiology

• Occurs in 0.5–2% of the population.
• More common in females.
• Often asymptomatic, discovered incidentally.

Embryology

• Caused by abnormal regression of the fourth aortic arch and right dorsal aorta during fetal development.
• Normally, the right subclavian artery arises from the brachiocephalic trunk.
• In ARSA, the proximal right fourth aortic arch disappears, leaving the distal portion to arise from the descending aorta.

Anatomical Course

• Originates from the distal aortic arch (posteriorly).
• Passes retroesophageal (most common) or between esophagus and trachea (less common) to reach the right arm.
• May compress the esophagus or trachea, producing symptoms.

Clinical Features

• Often asymptomatic.
• When symptomatic:
  • Dysphagia lusoria – difficulty swallowing due to esophageal compression.
  • Respiratory symptoms – cough, stridor, recurrent infections (if tracheal compression).
• Rarely associated with aneurysms (Kommerell diverticulum).

Imaging

• Barium swallow: indentation of the posterior esophagus.
• CT/MRI angiography: demonstrates aberrant course.
• Echocardiography (rarely) may show abnormal vessel origin.

Associated Anomalies

• Chromosomal anomalies (e.g., Down syndrome, DiGeorge syndrome) in some cases.
• May coexist with tetralogy of Fallot or congenital heart disease.

Management

• Asymptomatic: no treatment.
• Symptomatic:
  • Surgical correction (vascular reconstruction, reimplantation).
  • Endovascular stent in case of aneurysm (Kommerell diverticulum).

Etiology and anatomy

The term lusoria comes from the Latin phrase “lusus naturae,” meaning “trick of nature”. This anomaly is the most common congenital defect of the aortic arch and results from abnormal embryonic development. 

• Normal anatomy: Typically, the aorta gives rise to three main branches: the brachiocephalic artery (which then divides into the right subclavian and right common carotid arteries), the left common carotid artery, and the left subclavian artery.
• Arteria lusoria anatomy: With an ARSA, the brachiocephalic trunk is absent. Instead, the aortic arch has four main branches: the right common carotid, left common carotid, left subclavian, and finally, the ARSA, which arises from the distal arch.
• Path of the artery: After leaving the aorta, the ARSA travels upward and to the right, most commonly passing behind the esophagus. Less often, it passes between the trachea and esophagus or in front of the trachea. 

Clinical presentation

Arteria lusoria is often asymptomatic and discovered incidentally. However, symptoms can arise from the aberrant artery compressing nearby structures. 

• Dysphagia lusoria: The most common symptom is difficulty swallowing, or dysphagia, which was first linked to this anomaly in 1787 by David Bayford. The compression of the esophagus by the aberrant artery worsens with age as the vessels become more rigid.
• Dyspnea: Compression of the trachea can cause breathing difficulties, especially in infants.
• Other symptoms: Less common symptoms include chronic coughing, retrosternal chest pain, and weight loss.
• Late onset: While congenital, symptoms may not appear until adulthood due to age-related changes in the arteries, such as atherosclerosis, which increases the rigidity of the vessel and worsens compression. 

Diagnosis

Arteria lusoria can be detected using several imaging techniques:

• Barium esophagography: This X-ray test can show an extrinsic compression on the esophagus.
• Computed tomography (CT) and magnetic resonance imaging (MRI): These scans provide detailed images of the vascular anatomy, confirming the diagnosis and ruling out other causes of compression.
• Transradial catheterization: The anomaly may also be discovered during a coronary angiography procedure, as the unusual anatomy can make catheter insertion challenging. 

Management

The management of arteria lusoria depends on whether it is symptomatic.

• Asymptomatic cases: No treatment is necessary for individuals without symptoms.
• Symptomatic cases: Treatment is reserved for patients experiencing significant symptoms.
  • Conservative treatment: For mild cases, dietary modifications such as eating smaller, more chewed bites can help.
  • Surgical intervention: Severe cases may require surgical repair, which typically involves dividing the aberrant artery and re-implanting it to restore normal blood flow.
  • Minimally invasive options: Endovascular techniques using stents have shown promise as a less invasive alternative. 

Associated conditions

Arteria lusoria may occur with other congenital anomalies of the great vessels, including:

• Kommerell’s diverticulum: An aneurysmal dilation at the origin of the aberrant subclavian artery, which carries a risk of rupture.
• Bicarotid trunk: An anomaly where the right and left common carotid arteries share a common origin.
• Right-sided aortic arch: A related condition where the aortic arch passes to the right side of the trachea.