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Persistent Right Aortic Arch: A Common Birth Defect

Posted February 25, 2015 in Dog Diseases & Conditions A-Z

German Shepherd puppies

Persistent right aortic arch is a relatively common congenital birth defect often referred to as a “ring anomaly.” These are abnormalities in the major blood vessels at the base of the heart. These ring anomalies are sometimes completely benign but sometimes they entrap vital organs with serious consequences1.

While these abnormalities are inherited, the exact hereditary mechanism is unknown. The condition is most common in German Shepherds and Irish Setters but can occur in other breeds2,3.

Just what happens when this defect occurs is dependent on what organs are entrapped. In most cases the remnant (the ligamentum arteriosum) of the vessel wraps over the esophagus causing a stricture and a restriction of the flow of food down the esophagus to the stomach.

Clinical signs are usually begin when a puppy begins to eat solid foods. The esophagus in front of the stricture becomes distended and dilated and accumulated food is forced back forward and out of the mouth. This is not vomiting, which requires effort, but rather regurgitation (a more passive action).

Diagnosis of persistent arch
The diagnosis of a persistent arch is relatively simple. It involves having the dog swallow a meal mixed with a contrast medium (Barium sulfate) and taking radiographs. In some cases the esophagus will be dilated. The degree of dilation is an indication of the extent and severity of the abnormal esophagus. It can be a sign that the esophagus will have poor function even after surgery.

Prognosis of persistent arch
The degree to which the esophagus is damaged is an indication of the likelihood of recovery. If the condition is repaired promptly, the prognosis for excellent function is very good but becomes more guarded the longer the surgery is postponed. Untreated dogs will not develop to their normal size and will be generally unhealthy in appearance and small in size4.

Surgically dividing the ligament that is the result of the persistent arch will free the esophagus and allow normal passage of food. Recovery within a few months is likely. Less than 10% of dogs treated fail to improve4. Healing and return to normal esophageal function may be greatly helped by feeding the dog with his dish elevated so he must stand upright on his rear legs. This lets gravity assist in swallowing.

Because the condition is congenital and likely has some genetic cause, affected

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Mike has more than 35 years of experience in companion animal veterinary practice and is a valued member of IDEXX’s Pet Health Network team since 2013.