Teaching Case

A 43-year-old male patient was referred to our department for Computed Tomography (CT) angiography to eliminate a pulmonary embolism. He was admitted to intensive care for severe head trauma. His medical history was unremarkable. There was no dysphagia or dyspnoea.

Computed Tomography (CT) angiography was performed and incidentally revealed:
An aberrant right subclavian artery (arteria lusoria) which originates from the aortic arch
(Fig. 1) and crosses the midline between the spine and the oesophagus (Fig. 2) to reach the right side (Fig. 3). Both common carotid arteries originate from a common trunk .There was no abnormality of origin of the left subclavian artery (Fig. 2, 4, 5).
CT angiogram with 3D reconstruction (Fig. 5) shows a common origin of bilateral carotid arteries arising from the aortic arch who is called a truncus bicaroticus associated with arteria lusoria.

Aberrant right subclavian artery (ARSA) or arteria lusoria is the most common congenital aortic arch anomaly with a reported prevalence of 0.4–2% [1].
It is commonly associated with other congenital anomalies of the heart and great vessels resulting from embryologic malformation of the aortic arch, including truncus bicaroticus, which is a common trunk of bilateral common carotid arteries [2]. The association of ARSA and truncus bicaroticus is somewhat rare (about 29%) [3].
Arteria lusoria results from abnormal embryologic development of the aortic arch. The abnormal arterial origin is explained by the involution of the right fourth vascular arch with the proximal right dorsal aorta and the persistence of the right seventh intersegmental artery, which remains attached to the dorsal aorta: after the rotation of the dorsal aorta, the right seventh intersegmental artery becomes the ARSA. The artery crosses the midline between the oesophagus and vertebral column to reach the right side [4, 5].
Arteria lusoria is usually asymptomatic and is most often discovered incidentally during evaluation of other mediastinal anomalies, such as in our case. When symptomatic, the ARSA causes dysphagia lusoria from oesophageal compression, or dyspnoea and chronic coughing from tracheal compression. Truncus bicaroticus is a precondition for tracheal–oesophageal compression and the development of clinical symptoms [3, 4, 5]. Other symptoms are much rarer and are signs of aneurysmal dilatation of the proximal lusorian artery [6].
The diagnosis is based primarily on findings at chest radiography in association with those at oesophogography. The lateral projection chest radiography show the ARSA as a round, localized density continuous with the superior margin of the aortic arch [7].
MDCTA (multidetector row computed tomography angiography) and conventional angiography, including direct catheterization of the aberrant right subclavian artery, confirm the diagnosis [1].
Magnetic Resonance Angiography (MRA) is a non-invasive imaging modality and the most suited, currently used in the evaluation of thoracic aortic malformation including arteria lusoria and truncus bicaroticus [8].
There are several treatment options for an arteria lusoria. Surgical, endovascular, or combined interventions can be used. Treatment is indicated in symptomatic cases and also for prevention of complications due to aneurysmal dilatation of the lusorian artery.
Most patient with arteria lusoria are asymptomatic and rarely need a treatment [9].
Such was the case of our patient who was not operated due to the asymptomatic nature of the anomaly.