Difference between revisions of "Vascular Ring Anomalies"

Latest revision as of 19:22, 1 September 2015

Conditions included: Persistent Right Aortic Arch (PRAA) — Double Aortic Arch — Anomalous Subclavian Arteries

Introduction

Post-mortem specimen of an animal with a persistent right aortic arch
Alun Williams 2009 (RVC))

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, 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.

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 oesophagus and trachea are most often encircled by the left ligamentum arteriosum as they pass over the heart base causing chronic oesophageal and tracheal compression.

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

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.

Diagnosis

History and clinical signs plus age and breed may be indicative of the disease.

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.

Treatment

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.

Surgical treatment involves transecting the ligamentum arteriosum via an intercostal thoracotomy. The ligament should be ligated before transection in case a patent ductus arteriosus is also present.

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

Prognosis

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

Post-operative care is aimed at preventing aspiration pneumonia, and mainly involves dietary management. Normal food can be gradually reintroduced after 4 weeks.

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.

Vascular Ring Anomalies Learning Resources
Vetstream To reach the Vetstream content, please select	Canis, Felis, Lapis or Equis
Flashcards Test your knowledge using flashcard type questions	Small Animal Soft Tissue Surgery Q&A 19 Cardiovascular Developmental Pathology Flashcards

References

Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company

Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2) W.B. Saunders Company

Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier

Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial

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

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-Most commonly found in dogs and cats.  Acyanotic; clinical signs due to constriction of the [[Oesophagus - Anatomy & Physiology|oesophagus]]:
+{{OpenPagesTop}}
-*Regurgiation of food, usually noticed at weaning.
+Conditions included: '''''Persistent Right Aortic Arch (PRAA) — Double Aortic Arch — Anomalous Subclavian Arteries'''''
-*Aspiration pneumonia.
-====Persistent Right Aortic Arch====
+== Introduction==
+[[Image:Praa.gif|thumb|right|200px|<center>Post-mortem specimen of an animal with a persistent right aortic arch <br><small> Alun Williams 2009 (RVC))<center></small>]]
+This congenital condition is most commonly found in dogs after weaning, but is very rare in cats.
-Most common vascular ring anomaly, increased incidence in GSDs, and Irish setters.  vascular ring forms between the ductus arteriosus/ligamentum arteriosum and the persistent right aorta.
+'''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.
-[[Megaoesophagus]] is seen cranial to the constriction.
-Other causes include:
+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.
-[[Image:dextra-aorta.jpg|right|thumb|200px|<small><center>'''Dextra-aorta'''. Courtesy of A. Jefferies</center></small>]]
-====Double aortic arch====
+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 oesophagus and trachea are most often encircled by the left ligamentum arteriosum as they pass over the heart base causing chronic oesophageal and tracheal compression.
-====Anomalous subclavian arteries====
-Arise form the aortic arch rather than the brachiocephalic artery.
+When a young animal with PRAA is weaned onto solid food, the oesophageal and tracheal compression causes food stasis above the narrowed esophageal foramen leading to megaesophagus. Continued stress on the oesophagus in this manner can cause permanent damage. Additionally, [[Aspiration Pneumonia|aspiration pneumonia]] and the resulting respiratory distress is a complication of postprandial regurgitation.
-''Diagnosis:''
+== Clinical Signs ==
-*Ventral deviation of the trachea and dilation of the oesophagus on radiology.
-*Barium swallow definitive.
-''Treatment:''
+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'''.
-*Surgical resection possible.
-*Dietary management usually sufficient to control regurgitation.
+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 ==
+History and clinical signs plus age and breed may be indicative of the disease.
-*Seen most frequently in young animals right after weaning
+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.
-*Common in dogs
+'''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.
-*Very rare in cats
+== Treatment  ==
-===Signalment===
+'''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.
-*Genetics & Predisposed Breeds: Large breeds make up the majority of cases such as:
+Surgical treatment involves '''transecting the ligamentum arteriosum''' via an intercostal thoracotomy. The ligament should be ligated before transection in case a [[Patent Ductus Arteriosus|patent ductus arteriosus]] is also present.
-<gallery>
+A gastric tube is passed down the oesophagus to ensure no constrictions remain.
-Image:GermanShep.jpg|'''German Shepherd (Alsatian)'''<p> Ellen Levy Finch (2004) WikiMedia Commons
-Image:greatdane.jpg|'''Great Dane'''<p> Lilly M (2007) WikiMedia Commons
-</gallery>
-===Description===
+== Prognosis ==
-*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.
+'''Good with early surgical treatment''', but less favourable if there is extensive oesophageal damage.
-*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.
+Post-operative care is aimed at preventing aspiration pneumonia, and mainly involves '''dietary management'''. Normal food can be gradually reintroduced after 4 weeks.
-*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.
+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.
-===Diagnosis===
+{{Learning
-====History & Clinical Signs====
+|Vetstream = [https://www.vetstream.com/canis/Content/Disease/dis00916.asp, Vascular ring anomalies]
+|flashcards = [[Small Animal Soft Tissue Surgery Q&A 19]]
--Regurgitation (Postprandial=after meals)
+[[Cardiovascular Developmental Pathology Flashcards]]
+}}
--Coughing
+== References ==
--Respiratory distress
+Ettinger, S.J. and Feldman, E. C. (2000) '''Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat '''Volume 2 (Fifth Edition)'' W.B. Saunders Company''
--Small size
+Ettinger, S.J, Feldman, E.C. (2005)''' Textbook of Veterinary Internal Medicine '''(6th edition, volume 2) ''W.B. Saunders Company''
--Underweight (Malnourished)
+Fossum, T. W. et. al. (2007) '''Small Animal Surgery''' (Third Edition) ''Mosby Elsevier ''
--Increased appetite
+Merck & Co (2008) '''The Merck Veterinary Manual '''(Eighth Edition) ''Merial''
-====Physical Exam====
+Nelson, R.W. and Couto, C.G. (2009) '''Small Animal Internal Medicine '''(Fourth Edition) ''Mosby Elsevier''
--No cardiac murmurs unless PDA is also present
--Palpable dilated cervical esophagus
+{{review}}
+{{OpenPages}}
-====Radiographic Findings====
+[[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:Cardiology Section]]
--Megaesophagus in the thoracic inlet (+/- barium series)
-====Echocardiographic Findings====
-Not used to diagnose a PRAA
-====Electrocardiographic (ECG)====
-Not used to diagnose a PRAA
-===Treatment===
--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
-===Prognosis===
--Good with surgery
--Less favourable if there is extensive esophageal damage
-==from megaoesophagus page:
-[[Image:Praa.gif|right|thumb|125px|<center>Post-mortem specimen of an animal with a persistent right aortic arch <br><small> Copyright Alun Williams 2009 (RVC))</center></small>]]
-Vascular rings are congenital abnormalities of the aortic arch system which interfere with [[Oesophagus - Anatomy & Physiology|oesophageal]] function. Many vascular anomalies (such as an aberrant right subclavian artery) are clinically silent and up to 20% of dogs and cats may possess such an anomaly.  Clinically significant anomalies are found most commonly in large breed dogs, particularly Irish setters and German Shepherd dogs.
-The most common clinically significant anomaly is a '''dextra-aorta''' or '''persistent right aortic arch''', in which the aorta is formed by the fourth right branchial arch rather than the fourth left arch.  In the normal animal, the aorta, pulmonary artery and ductus arteriosus (which connects the former vessels) all lie on the left side of the oesophagus but, when the aorta develops on the right, the ductus arteriosus must pass across the oesophagus to reach the aorta.  The oesophagus is then trapped within a ring formed by the '''aorta''' (on the right), the '''main pulmonary artery''' (on the left), the '''ductus arteriosus''' (or ligamentum arteriosum) dorsally and the '''heart base''' ventrally.  The compression and stricture produced by the vascular ring prevents the passage of solid food beyond the heart base and food accumulates cranial to the obstruction.  This results in dilation (megaoesophagus) which is usually confined to the cranial thoracic region but, in chronic cases, may extend along its entire length.
-The condition usually becomes apparent at weaning when animals start to eat solid food that cannot pass through the constricted region.  Affected animals tend to regurgitate undigested solid food but, if they are presented for treatment before severe dilation occurs, surgical correction of the ring (if possible) should result in a good prognosis.
-==Test yourself with the Developmental Pathology Flashcards==
-[[Developmental_Pathology_Flashcards_-_Pathology|Developmental Pathology Flashcards]]
-[[Category:Cardiovascular_System_-_Developmental_Pathology]]
-[[Category:To_Do_-_Cardiovascular]]
-[[Category:Cardiac Diseases - Cat]][[Category:Oesophageal Diseases - Cat]][[Category:Cardiac Diseases - Dog]][[Category:Oesophageal Diseases - Dog]]
-[[Category:Cardiac Diseases - Horse]][[Category:Oesophageal Diseases - Horse]]
-[[Category:Cardiac Diseases - Cattle]]