An adult domestic female pig (Sus scrofa) exhibited clinical signs of right
-sided Horner's syndrome after experimental placement of a woven aortic ste
nt followed by aortic catheterization, The clinical signs included a miotic
pupil, ptosis of the upper eyelid, prolapse of the nictitating membrane, a
nd enophthalmos. Necropsy revealed a large mass in the right midcervical re
gion that encased or was in contact with the carotid artery, internal jugul
ar vein, and vagus nerve. Closer evaluation of the mass revealed that it wa
s a small piece of surgical suture material that was embedded within the lu
men of the carotid artery. This extrinsic material served as a nidus for an
inflammatory reaction involving the vagus nerve.