Utility of endoscopic ultrasound in the diagnosis of aberrant right subclavian artery.

Background And Aims: Aberrant right subclavian artery (ARSA) is the most common congenital anomaly of the aortic arch occurring in 0.4-2.0% of the general population. Instead of arising from the brachiocephalic artery, the ARSA arises as the last branch from the aortic arch. The aim of this study was to determine the prevalence of ARSA in patients undergoing upper endoscopic ultrasound (EUS) and to describe the EUS characteristics of ARSA.

Methods: A retrospective review was conducted of 7513 upper EUS exams performed from 1 July 2000 to 1 February 2005.

Results: In total, 27 (0.36%, 95% CI 0.22-0.50%) of 7513 patients undergoing upper EUS were found to have an ARSA (10 male, 17 female; mean age 58 years, range 23-81 years). Of the 27 patients, 16 had only radial EUS, 10 had radial and linear EUS, and one had only linear EUS. In all 26 patients who underwent radial imaging, a well-defined, anechoic tubular structure was seen originating from the aortic arch and passing between the esophagus and spine. In all 11 patients undergoing linear imaging, the abnormal anatomy was detected and the vascular nature confirmed by Doppler. In one patient, both radial and linear imaging identified unsuspected aneurismal dilatation of the ARSA; a rare condition referred to as Kommerell's diverticulum (KD). None of the other 26 patients had symptoms to suggest an ARSA. Of the 14 patients who had computed tomography (CT) prior to EUS, only four were initially reported to have ARSA. However, later review of the CT scans verified an ARSA in all 14 patients. Of the two patients who underwent a barium swallow, only one had findings suggestive of ARSA.

Conclusions: This report highlights the utility of both radial and linear EUS imaging in identifying previously unsuspected ARSA and associated anomalies. This report also suggests the need for careful review of the CT in patients suspected of having ARSA due to the frequent failure of radiologists to identify, or report, this anomaly when particular focus is not given.