Vascular Ring Anomalies

CARDIOLOGY ()Map CARDIOVASCULAR CONDITIONS (Map)

Dextra-aorta. Courtesy of A. Jefferies

Genetics & Predisposed Breeds: Large breeds make up the majority of cases such as:

During normal embryonic development there are five pairs of aortic arch arteries (1-6, 5 is absent) that undergo developmental changes necessary to form the major arteries of the head, neck, and upper thorax.

Malformations of the aortic arch arteries can cause several vascular ring anomalies, but the most commonly seen anomaly is persistent right aortic arch (PRAA). With PRAA, the esophagus and trachea are most often encircled by the left ligamentum arteriosum as they pass over the heart base causing chronic esophageal and tracheal compression.

When a young animal with PRAA is weaned onto solid food, the esophageal and tracheal compression causes food stasis above the narrowed esophageal foramen leading to megaesophagus. Continued stress on the esophagus in this manner can cause permanent damage. Additionally, aspiration pneumonia and the resulting respiratory distress is a complication of postprandial regurgitation.

-Regurgitation (Postprandial=after meals)

-Coughing

-Respiratory distress

-Small size

-Underweight (Malnourished)

-Increased appetite

-No cardiac murmurs unless PDA is also present

-Palpable dilated cervical esophagus

-Megaesophagus in the thoracic inlet (+/- barium series)

Not used to diagnose a PRAA

Not used to diagnose a PRAA

-Surgical sectioning of the vascular ring anomaly to relieve constriction of the esophagus and trachea

-Management of esophageal damage: frequent feeding of small semi-solid/liquid meals from an elevated position

-Good with surgery

-Less favourable if there is extensive esophageal damage