By Laura Selmic, BVetMed (Hons), MRCVS, DACVS-SA, ACVS Founding Fellow of Surgical Oncology
A 13-week-old, mixed-breed puppy named Kim recently presented to the Soft Tissue Surgery Service at the Veterinary Teaching Hospital with the main complaint of persistent regurgitation after eating.
Radiographs showed Kim had dilation of her esophagus to the level of the heart base. Given the localized nature of the esophageal dilation and her young age, a persistent right aortic arch (PRAA) was suspected and a CT scan with contrast was performed to confirm and aid in the planning of the surgery.
The CT images revealed Kim had a persistent right aortic arch with a left ligamentum arteriosum. This is the most common vascular ring abnormality, occurring in 95 percent of clinical cases of dogs with vascular ring anomalies. In addition, she also had another two abnormal vessels present: an aberrant left subclavian artery and hemiazygos vein. An intercostal thoracotomy was performed at the left fourth intercostal space and the ligamentum arteriosum was isolated, ligated and divided. This effectively released the constriction around the esophagus, allowing it to open up to allow passage of a stomach tube. Kim recovered well from surgery and was able to go home the following day.
Any breed of dog can have this congenital disease. Dogs most commonly present as puppies at the time of weaning. A classic history from an owner is that the dog was doing well drinking milk but began to regurgitate after starting to eat solid food.
Vascular ring anomalies can cause regurgitation due to formation of a partial or full vascular ring around the esophagus resulting in constriction. Rarely, a vascular ring can be present around the trachea as well resulting in difficulty breathing. It is possible dogs with vascular ring anomalies can also experience difficulty breathing as result of aspiration pneumonia following regurgitation. If a vascular ring anomaly is suspected, chest radiographs can be performed and may help to assess esophageal abnormalities and rule out aspiration pneumonia.
The next step will often be referral to a specialist in small animal surgery. CT or endoscopy may be performed to further characterize the abnormality to help plan which surgical approach and treatment is needed.
Surgery can be performed in a young puppy but often we will try to wait until the pup is 12 weeks old, as the pup will have a fully developed autonomic nervous system and cope better with anesthesia. The type of surgery necessary depends on which vascular ring anomaly is present. The most common is persistent right aortic arch with left ligamentum arteriosum.
Dogs can recover well following chest surgery and often can return home 1 to 3 days after surgery. The esophagus may show significant dilation in front of the heart base prior to surgery, but the majority of dogs have a good quality of life and do not experience regurgitation after surgery.