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What is the aetiology of this condition?

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An aberrant right subclavian artery results from involution of the entire right fourth embryonic arch with persistence of the right seventh intersegmental artery (which gives rise to the right subclavian artery); the latter maintains its attachment to the descending aorta. The aortic arch branches arise in the following order: right common carotid, left common carotid, left subclavian, and right subclavian arteries. The aberrant right subclavian artery may arise from an aortic diverticulum that may result from persistence of the dorsal portion of the embryonic arch.

What is the usual presentation?

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Affected patients are typically asymptomatic adults. Patients with associated right ligamentum arteriosus have a complete vascular ring and may have symptoms. In addition, symptoms of tracheal compression have been described in affected children, particularly those with associated common origin of the carotid arteries. With aneurysmal dilatation of the aberrant vessel, oesophageal compression may produce symptoms. In these cases, the aberrant vessel has been called “arteria lusoria” and the symptom “dysphagia lusoria” (from the Latin lusus naturae, meaning “game” or “freak of nature”).

What are the clinical implications of this condition?

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1. An aberrant right subclavian artery is a significant incidental finding in patients who undergo cardiac catheterization through the right arm as the catheter typically enters the descending aorta and cannot be maneuvered into the ascending aorta. 2. An aberrant right subclavian artery in a patient with aortic coarctation typically arises distal to the coarctation. A right vertebral subclavian steal may result in these cases from retrograde flow from the right subclavian artery into the descending thoracic aorta. Affected patients may exhibit unilateral left rib notching.