Persistent right aortic arch

The term vascular ring anomaly describes several disorders that occur because of abnormal development of the blood vessels that arise from the aortic arch in the fetus. The most common abnormality is a persistent right aortic arch which develops instead of the left aortic arch that would normally become the permanent aorta, the main blood vessel leading from the heart.

These anomalies are relatively common in dogs. They do not cause cardiovascular problems; however the abnormal blood vessel forms a ring which entraps the esophagus and sometimes the trachea, causing regurgitation, unthriftiness, and often aspiration pneumonia.

What breeds are affected by persistent right aortic arch?
There is an increased incidence of this disorder in the Great Dane, German shepherd and Irish setter, relative to other breeds.

What does a persistent right aortic arch mean to your dog & you?
Signs associated with entrapment of the esophagus usually become apparent shortly after weaning, when the dog begins eating semi-solid or solid food. The partial obstruction of the esophagus causes regurgitation and, over time, dilation of the esophagus ahead of the obstructed area. Dogs with this condition are thin, may be malnourished and have ravenous appetites. They are prone to aspiration pneumonia.

These anomalies can be corrected surgically. It is important to do so before there is permanent damage to the esophagus.

How is a persistent right aortic arch diagnosed?
In a dog that begins regurgitating shortly after weaning, this condition is suspected. Chest x-rays will confirm this, in particular a contrast study with barium which will show the dilated esophagus just ahead of the obstruction, located at the base of the heart. It is important to differentiate this condition from megaesophagus, which causes similar signs and in which the esophagus is dilated throughout its length.

How is a persistent right aortic arch treated?
Treatment is surgical. The constricting ring is separated. Surgery should be performed early, before permanent damage has occurred to the lining of the esophagus due to distension.

Postoperative care involves feeding a liquid diet with gradual introduction of frequent small meals. In some dogs occasional regurgitation may persist.