Right aortic arch analysis - Anatomical variant or serious vascular defect?

The right-sided aortic arch (RAA) is a rare congenital defect of the aorta. The aim of the study was to assess the occurrence of RAA in diagnoses performed by the University Radiology Department and analyze the frequency of concomitant vascular abnormalities.

The database of the Radiology Department was retrospectively analyzed between January 2008 and May 2016 with the keyword "right aortic arch". Twenty patients with this diagnosis were identified from a total of 11,690 CT examinations of the chest area, 19,623 CT examinations of brain-supplying vessels, and 1863 MRI examinations of the heart and aortic arch or brain-supplying arteries. The type of aortic arch, the occurrence of Kommerell's diverticulum and possible other vascular abnormalities, such as stenosis, kinking or occlusion, were then investigated.

The analysis identified nine patients with type I and 11 patients with type II RAA. Eight of the 11 type II patients presented Kommerell's diverticulum. Concomitant vascular abnormalities were detected in four patients with type II RAA. In two cases, the right common carotid artery (RCCA) was narrowed by up to 80%, with steal phenomenon confirmed in one of them. In the second coincident right subclavian artery (RSA) stenosis was depicted. In two other cases, the aberrant left subclavian arteries (ALSA) were found to be narrowed at the level of origin by up to 70%. One patient was found with type B aortic dissection including ALSA and Kommerell's diverticulum.

Our observations indicate that concomitant vascular abnormalities may occur more often than reported in literature. Patients diagnosed with type II RAA should be examined with Doppler ultrasonography to identify coincident vascular disorders, especially stenosis of the common carotid arteries or subclavian arteries.