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

Objective: To describe the circumflex left aortic arch as a new form of canine congenital vascular ring anomaly leading to esophageal constriction.

Animals: 3 large-breed dogs of variable age: a 9-month-old entire male German Shepherd Dog-Rottweiler cross, a 17-week-old entire male German Shepherd Dog, and a 9-year-old neutered female Labrador Retriever, seen between April 2022 and May 2023.

Clinical Presentation: Dogs presented for chronic postprandial regurgitation and poor growth.