Aberrant Right Subclavian Arteries in Dogs Have a Prevalence of 1.2% and Are More Likely to be an Incidental Finding on Computed Tomographic Studies of the Thorax

Aberrant right subclavian arteries (ARSAs) are a form of vascular ring anomaly (VRA) in dogs and the most common VRA in people. To date, there has been no large-scale study on ARSA in dogs and their potential clinical significance. For part one, a single-center retrospective observational study was performed to determine the prevalence of ARSAs in a population of 1000 dogs undergoing contrast-enhanced CT for various reasons. For part two, further canine ARSA cases were collected to characterize their imaging features further and determine whether any imaging findings were more frequent in dogs with clinical signs attributed to a VRA. The prevalence of ARSA was 1.2% (12/1000). For part two, out of a total of 37 dogs with ARSA, this finding was thought to be incidental in 28 cases (75.6%), clinically relevant in 1 case (2.7%), and potentially relevant in 8 cases (21.6%). Cranial esophageal dilation with gas and fluid and esophageal compression at the site of the ARSA crossing the esophagus was found in the case where the ARSA was considered relevant. Esophageal dilation with esophageal compression by the ARSA was also more frequent in the potentially relevant group. Our study shows that an ARSA is more likely to be an incidental finding; however, due to the low number of cases where the ARSA was considered relevant, no specific imaging findings were found that could help determine their clinical relevance.