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This congenital condition is most commonly found in dogs after weaning, but is very rare in cats.  

This congenital condition is most commonly found in dogs after weaning, but is very rare in cats.  

'''Persistent Right Aortic Arch''' is the most common vascular ring anomaly, increased incidence in German Shepherd Dogs, and Irish setters. Vascular ring forms between the ductus arteriosus/ligamentum arteriosum and the persistent right aorta. [[Megaoesophagus]] is seen cranial to the constriction. Other causes include a '''double aortic arch''' and '''anomalous subclavian arteries'''. These arise from the aortic arch rather than the brachiocephalic artery.  

'''Persistent Right Aortic Arch''' is the most common vascular ring anomaly, increased incidence in German Shepherd Dogs, Irish setters and Great Danes. Vascular ring forms between the ductus arteriosus/ligamentum arteriosum and the persistent right aorta. [[Megaoesophagus]] is seen cranial to the constriction. Other causes include a '''double aortic arch''' and '''anomalous subclavian arteries'''. These arise from the aortic arch rather than the brachiocephalic artery.  

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.

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.

== Clinical Signs ==

== Clinical Signs ==

Clinical signs are usually due to constriction of the oesophagus, such as regurgitation of food, usually noticed at weaning and aspiration pneumonia. This may be seen as coughing. The animal may present as '[[vomiting]]' but thorough history and physical exam should distinguish this from regurgitation. Respiratory distress may also be seen. Stunted growth, thin and malnourished with an increased appetite may also be a clinical sign.  

Clinical signs are usually due to constriction of the oesophagus, such as '''regurgitation of food''', usually noticed at weaning and aspiration pneumonia. This may be seen as '''coughing'''.  

 

The animal may present as '[[vomiting]]' but thorough history and physical exam should distinguish this from regurgitation.  

 

Respiratory distress may also be seen. '''Stunted growth''', thin and malnourished with an increased appetite may also be a clinical sign.  

== Diagnosis ==

== Diagnosis ==

On physical exam, there will be no cardiac murmurs unless a [[Patent Ductus Arteriosus]] (PDA) is also present. A palpable dilated cervical oesophagus may be detected.

On physical exam, there will be no cardiac murmurs unless a [[Patent Ductus Arteriosus]] (PDA) is also present. A palpable dilated cervical oesophagus may be detected.

Radiographs should be taken for further diagnostics and will show a ventral deviation of the trachea and dilation of the oesophagus. A barium swallow will provide definitive diagnosis of this condition.

'''Radiographs''' should be taken for further diagnostics and will show a ventral deviation of the trachea and dilation of the oesophagus. A '''barium swallow''' will provide definitive diagnosis of this condition.

== Treatment  ==

== Treatment  ==

Surgical resection of the vascular ring anomaly is possible, by referral to a specialist cardiac surgeon. Dietary management is usually sufficient to control regurgitation, such as feeding from a platform and feeding small amounts of liquidised food. 

'''Surgical resection''' should be performed as soon as possible. '''Aspiration pneumonia''' should be treated first if present, and dietary management should be put in place to minimise regurgitation: this involves feeding a liquid or gruel diet in small amounts from an elevated position.

 

 

A gastric tube is passed down the oesophagus to ensure no constrictions remain.

== Prognosis ==

== Prognosis ==

Good with surgery, but less favourable if there is extensive oesophageal damage. If surgery cannot be performed, for whatever reason, then thoughts into the quality of life of the animal without surgery must be taken into consideration.  

'''Good with early surgical treatment''', but less favourable if there is extensive oesophageal damage.  

 

 

If surgery cannot be performed, for whatever reason, then thoughts into the quality of life of the animal without surgery must be taken into consideration.  

== Test yourself with the Developmental Pathology Flashcards ==

|flashcards = [[Small Animal Soft Tissue Surgery Q&A 19]]

[[Cardiovascular Developmental Pathology Flashcards]]  

[[Cardiovascular Developmental Pathology Flashcards]]  

== References ==

== References ==

Nelson, R.W. and Couto, C.G. (2009) '''Small Animal Internal Medicine '''(Fourth Edition) ''Mosby Elsevier''

Nelson, R.W. and Couto, C.G. (2009) '''Small Animal Internal Medicine '''(Fourth Edition) ''Mosby Elsevier''

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[[Category:Cardiovascular_System_-_Developmental_Pathology]] [[Category:Oesophagus_-_Pathology]] [[Category:Expert_Review - Small Animal]] [[Category:Cardiac_Diseases_-_Cat]] [[Category:Oesophageal_Diseases_-_Cat]] [[Category:Cardiac_Diseases_-_Dog]] [[Category:Oesophageal_Diseases_-_Dog]]

[[Category:Cardiovascular_System_-_Developmental_Pathology]] [[Category:Oesophagus_-_Pathology]] [[Category:Expert_Review - Small Animal]] [[Category:Cardiac_Diseases_-_Cat]] [[Category:Oesophageal_Diseases_-_Cat]] [[Category:Cardiac_Diseases_-_Dog]] [[Category:Oesophageal_Diseases_-_Dog]]