Vascular Ring anomalies (PRAA)
description
Transcript of Vascular Ring anomalies (PRAA)
Vascular Ring anomalies(PRAA)
Buster
• 8 week old Border collie
• Regurgitation/vomiting recently since starting to feed kibble
• Smaller than the rest of his littermates
• Always hungry
Thoracic Radiographs
Cranial thoracic megaesophagus
Leftward deviation of the tracheaAbsent left margin of the aorta
EMBRYOLOGY
Vascular Ring Anomalies: Case Report and Brief Overview. Can. Vet. J. 20: 78-81(March 1979)
Embryology• The FIRST and SECOND arches regress and the internal and external
carotids are formed by the dorsal and ventral aortas respectively. • The dorsal aortas between the third and fourth arches regress leaving
the THIRD arch as part of the internal carotid artery. • The left FOURTH arch enlarges to form the main aortic arch while • The right FOURTH arch becomes the right subclavian artery. • The FIFTH arch is vestigial and of no apparent clinical significance. The
SIXTH arches become the pulmonary arteries. • The left SIXTH arch retains its connection with the left dorsal aorta as
the ductus arteriosus. • Many variations of the vascular ring anomaly based on degrees of
patency and association with other cardiac lesions have been described.Vascular Ring Anomalies: Case Report and Brief Overview. Can. Vet. J. 20: 78-81(March 1979)
VRAs
• Congenital malformations of the major arteries of the heart that entrap the intrathoracic esophagus causing esophageal obstruction
• PRAA is the most common: R aa rather than the L 4th aa becomes the functional aorta
• Causes: Circular entrapement of the esophagus– Aorta on the right, ligamentum arteriosum
dorsolaterally on the left, PT on the Left and the heart base ventrally
5 MAIN FORMS OF VASCULAR RING ANOMALIES
• 1. Double aortic arch: both fourth arches maintain their attachment to the adult descending aorta.
• 2. Right aortic arch with left ductus arteriosus: ring formed by the normal ductus arteriosus from the left pulmonary arch joining to the abnormal right aortic arch.
• 3. Left aortic arch with right ductus arteriosus: ring formed by the abnormal communication between the right pulmonary arch and the normal aortic arch.
• 4. Aberrant right subclavian artery: origin of the artery such that the vessel must pass retro-esophageal and thus put pressure on the esophagus, trachea, etc.
• 5. Aberrant left subclavian artery: as for the aberrant right subclavian artery.
Clinical Signs
• Result from constricted esophagus– Regurgitation of solid food after weaning– Wt loss with failure to thrive despite good
appetite– Moist cough, fever, dyspnea: if aspiration
pnuemonia present– PE: thin stunted animal– Breed predisposition: Irish Setters and German
Shephards
Diagnosis
• Thoracic rads:– cranial megaesophagus cranial to the base of the
heart– Leftward deviation of the trachea near the cranial
border of the heart• Esophagram: Confirm location of esophageal
constriction and evaluate esophageal motility to help give prognosis of function post-sx
Diagnostics
• CT: to confirm type of VRA present.– Some animals may have more than 1 anomalous
vessel– Will give surgeon more information to plan sx
accordingly• Echocardiogram– May be able to identify anomalous vessel and/or
other congenital abnormalities
PRAA
MEGAESOPHAGUSAORTA
DUCTUS ARTERIOSUS
Left pulmonary arch
Multiple anomalous vessels
• 3 month old GSD: PRAA, PDA, persistent retroeshageal left subclavian artery, persistent left cranial vena cava and left azygous vein
Multiple vascular anomalies in a regurgitating German shepherd puppy. Christiansen, Snyder, Buchanan, and Holt. Journal of Small Animal Practice(2007) 48, 32-35
Persistent left cranial vena cava
Treatment
• Surgical ligation and transection of the ligamentum arteriosum
• Tx aspiration pneumonia if present
• Esophageal hypomotility and regurgitation may persist elevated feedings and promotility medications
PRAA
Thrall. Textbook of Veterinary Radiology. Fifth edition; 2007. p 505-506
Double Aortic Arch
Thrall. Textbook of Veterinary Radiology. Fifth edition; 2007. p 505-506
Aberrant Right Subclavian
Thrall. Textbook of Veterinary Radiology. Fifth edition; 2007. p 505-506