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1031.e2 Vascular Ring Anomaly

Vascular Ring Anomaly Client Education
Sheet
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brachiocephalic trunk and left subclavian
BASIC INFORMATION
left aorta:
arteries off the ascending aorta. Aberrant right subclavian artery with a normal
Definition Pathophysiology: • Can cause an incomplete ring because the
Congenital malformation of one or more parts • Developmental anomalies of the great vessels aberrant vessel courses over and dorsally
of the aortic arch during embryogenesis such appear to be relatively common, but these compresses the esophagus.
that vessels encircle the esophagus and trachea, anomalies are clinically important only when
causing compression the vessels entrap the esophagus and trachea DIAGNOSIS
within a vascular ring.
Synonyms • Passage of food down the esophagus is Diagnostic Overview
Vascular ring malformation; persistent right impeded by the vascular ring, causing A history of regurgitation beginning immedi-
aortic arch (PRAA), which is the most common esophageal dilation, food stasis, and regur- ately after weaning is highly suggestive; plain
vascular ring anomaly gitation. Regurgitation with aspiration can thoracic radiographs provide the basis for a
cause pneumonia. diagnosis of vascular ring anomaly (e.g., ventral
Epidemiology PRAA (most common in dogs): and leftward tracheal deviation, dilated cranial
SPECIES, AGE, SEX • The normal left aortic arch regresses, and esophagus) and screen for associated aspiration
• Dogs > cats; no sex predisposition the right aortic arch is retained. The left pneumonia.
• Clinical signs usually develop shortly after ligamentum arteriosum passes over the
weaning. esophagus, connecting the right aortic arch Differential Diagnosis
to the left-sided pulmonary artery and • Differential diagnoses for regurgitation
GENETICS, BREED PREDISPOSITION compressing the esophagus at the base of include congenital megaesophagus, stricture,
• Most dogs with PRAA are of large breeds the heart. foreign body, neoplasia, granuloma, hiatal
(>15 kg adult weight). • PRAA can also occur with an aberrant left disorder, and esophageal diverticulum.
• Heritability is suspected in German shep- subclavian artery. This causes an incomplete • Esophageal stricture is the major differential
herds, greyhounds, and German pinschers. ring that dorsally compresses the esophagus diagnosis to consider for radiographic
(left subclavian arises from the right aorta esophageal dilation that terminates at the
ASSOCIATED DISORDERS and courses dorsally over the esophagus). base of the heart.
• Persistent left cranial vena cava and patent Double aortic arch:
ductus arteriosus (PDA) can be concurrent • Left and right aortic arches persist, encircling Initial Database
vascular anomalies. the esophagus and trachea as the two vessels Thoracic radiographs:
• Megaesophagus and aspiration pneumonia merge to form the descending aorta. Due • The esophagus may appear dilated to but not
are secondary problems associated with to compression of the trachea, respiratory past the base of the heart on plain films. Its
chronic partial esophageal obstruction. signs are more common with this anomaly. visualization may be enhanced by residual
Persistent right ligamentum arteriosum with food. Lateral radiographs often show ventral
Clinical Presentation normal left aorta: deviation of the trachea cranial to the heart,
HISTORY, CHIEF COMPLAINT • An uncommon cause of a vascular ring and the tracheal lumen may be narrowed in
Most dogs and cats develop clinical signs after anomaly. It is important to note that cor- this deviated segment.
they start to ingest solid food because the rection by a left lateral thoracotomy is more • Leftward curvature of the trachea near the
vascular ring obstructs passage of food down difficult for this malformation than for the cranial border of the heart on the dorso-
the esophagus. Postprandial regurgitation is the other vascular ring anomalies. ventral (DV) or ventrodorsal (VD) view
usual presenting complaint, and most cases are
diagnosed before 6 months of age. Occasionally,
animals may present with coughing or respira-
tory distress due to aspiration pneumonia or
tracheal compression.

PHYSICAL EXAM FINDINGS
Animals have a good appetite but may be thin
as a result of chronic regurgitation. An enlarged
esophagus may occasionally be palpated in the
thoracic inlet, especially after eating. Animals
with aspiration pneumonia may be febrile
with harsh ventral lung sounds or pulmonary
crackles.
Etiology and Pathophysiology
Normal embryogenesis:
• In the embryo, the great vessels are formed
from six aortic arches that connect paired
ventral and dorsal aortas. During develop-
ment, these vessels undergo regression
and reconnection that normally result in VASCULAR RING ANOMALY Lateral thoracic radiograph demonstrates marked ventral deviation of the
a left-sided aorta, left-sided ligamentum trachea and severe esophageal filling with fluid/soft-tissue opacity material cranial to the carina. The cause
arteriosum, and normal branching of the was a vascular ring anomaly.

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