Persistent right aortic arch with an aberrant left subclavian artery, Kommerell’s diverticulum and bicarotid trunk in a 3-year-old cat

CASE SUMMARY A 3-year-old male, neutered, domestic shorthair cat with a history of chronic regurgitation since being obtained as a kitten was presented for weight loss and regurgitation of all ingested food. The cat was in poor body condition and had a firm swelling in the ventral neck at the time of presentation. Thoracic radiographs showed severe dilation of the entire cervical and cranial intrathoracic esophagus to the level of the heart base. Computed tomographic angiography (CTA) showed a persistent right aortic arch with an aberrant left subclavian artery and severe dilation of the cervical and intrathoracic esophagus cranial to the heart base. CTA also showed a bicarotid trunk and Kommerell's diverticulum to be present, which are rare vascular structures in the cat. Esophagoscopy showed esophageal dilation and multiple compact trichobezoars obstructing the esophagus. Removal of the obstructing trichobezoars resulted in resolution of clinical signs, and the cat was able to drink water and eat a canned food slurry without regurgitation. Surgical correction was not pursued. RELEVANCE AND NOVEL INFORMATION Vascular ring anomaly (VRA) should be considered in all cats with a history of regurgitation, regardless of their age at the time of presentation. CTA is a valuable diagnostic imaging procedure that allows differentiation of a VRA from other causes of esophageal obstruction and provides information about the VRA that can be used to determine amenability to surgical correction.