Unusual morphology of an aberrant right subclavian artery: a case report and systematic review of cadaveric studies .

Background: An aberrant right subclavian artery (ARSA) is a rare vascular anomaly defined by the origin of the right subclavian artery from the aorta, distal to the left subclavian artery (LSA). An ARSA was found in an 83-year-old female during cadaveric dissection for anatomy teaching, which had an unusually narrow lumen compared to previously reported cases.

Materials and methods: The specific morphology of this ARSA variant was characterised by further dissection and measurements. A systematic review of cadaveric case reports with quantitative evaluation of ARSA dimensions was conducted for comparison with this case.

Results: This ARSA variant exhibited an unusually narrow lumen (8.22 mm²) compared to the LSA (152.55²), with an ARSA: LSA ratio of 0.24. The systematic review included 17 studies with 23 cases of ARSAs. Of these cases, 20 contained details of ARSA diameter, 19 of which were wider than in this case. In all studies where both ARSA and LSA diameters were measured, ARSA was found to be significantly wider than LSA (mean ratio of ARSA to LSA: 1.49, range: 1.09-2.00). Several other variations were reported in these studies, such as concomitant aortic arch branch anomalies and differing origins of ARSA as defined by vertebral level and relation to the aortic arch.

Conclusions: This case report presents an unusually narrow ARSA which has not been previously described in the literature. As there is limited evidence on how ARSA morphology affects clinical outcomes, further research is needed to better inform management of ARSAs.