Circumflex left aortic arch: a new vascular ring anomaly in dogs.

Circumflex left aortic arch is a newly discovered rare type of congenital vascular ring anomaly in dogs, which presents a similar anatomical derangement to the human form. Clinical signs include postprandial regurgitation and poor growth. Circumflex left aortic arch vascular anomaly cannot be surgically corrected via the left thoracotomy that is commonly used for the more common vascular ring anomalies in dogs. Computed tomography is a useful diagnostic modality for the diagnosis of this condition, detection of concomitant congenital vascular malformations, evaluation of associated pathologies, and surgical planning.