Vascular ring anomalyaccession 180393

Katie Phillips

Corky7 mo male intact South Down sheep

Corky• Presented to NCSU for

1 month history of regurgitation and multiple episodes of bloat.

• Owner has had for only a little over a month

• Only eats alfalfa leaves and avoids all stems and has been seen to regurgitate grain.

Corky

Corky - esophagram

• Boluses of liquid barium 30% wt/vol by dose syringe

• Oroesophageal tube with negative contrast

Corky• Focal esophageal narrowing along cranial margin of heart base

Anatomy

Anatomy

Embryology• Embryological arches are paired: some segments

persist after birth as normal vessels while others regress.

Persistent right aortic arch

• Right aortic arch instead of left• Esophagus is entrapped by the

ligamentum arteriosus that tethers the aorta to the left pulmonary artery.

• Segmental esophageal dilation with constriction just cranial to tracheal bifurcation.

PRAA• Radiographic signs: – Leftward deviation of trachea– Absence of left margin of

descending aorta• Left subclavian artery - may cause

shallow indentation cranial to constriction on VD view.

• Persistent left cranial vena cava – complicates surgery, can no longer just do lateral PDA surgery.

Double aortic arch

• Esophagus is entrapped between aortic arches and heart base

• Only vascular ring anomaly that can also encircle the trachea and cause dyspnea.

Aberrant right subclavian artery

• Right subclavian artery arising directly from aorta crosses over top of esophagus left to right.

• Causes dorsal constriction of esophagus, tends to be more cranial than PRAA.