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Evaluation of In Vivo Behavior of Ameroid Ring Constrictors in Dogs with Congenital Extrahepatic Portosystemic Shunts Using Computed Tomography
Author(s) -
Hunt Geraldine B.,
Culp William T. N.,
Mayhew Kelli N.,
Mayhew Philipp,
Steffey Michele A.,
Zwingenberger Allison
Publication year - 2014
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/j.1532-950x.2014.12196.x
Subject(s) - medicine , occlusion , shunt (medical) , portosystemic shunt , radiology , surgery , portal hypertension , cirrhosis
Objective To evaluate the in vivo pattern of ameroid constrictor closure of congenital extrahepatic portosystemic shunts in dogs. Study Design Prospective study. Animals Dogs (n = 22) with congenital extrahepatic portosystemic shunts. Methods Contrast‐enhanced computed tomography was performed immediately before, and at least 8 weeks after placement of ameroid ring constrictors. Plastic‐encased ameroid constrictors were used in 17 dogs and metal constrictors in 5 dogs. Presence of residual flow through the portosystemic shunt, additional anomalous vessels, acquired shunts and soft tissue associated with the ameroid constrictor was recorded. Postoperative internal diameter was recorded for the 17 plastic constrictors. Correlations between internal diameter and pre‐ and postoperative serum protein concentration were analyzed. Results No ameroid constrictor closed completely: shunt occlusion was always dependent on soft tissue within the ameroid ring. Residual flow through the shunt was present in 4 dogs (18%), although this caused persistent elevation of shunt fraction in only 1 dog (dog 8). The change in ameroid constrictor internal diameter was not significantly correlated with serum protein concentration. Conclusions Complete shunt occlusion after AC placement is usually dependent on soft tissue reaction. Ameroid constrictors ≥5 mm diameter may not promote complete shunt occlusion.