Prototype stent: in vivo swine studies in the biliary system.
OBJECTIVE
To evaluate the safety of implantation and the biocompatibility of a new balloon-expandable stent in the biliary system of the swine model.


METHODS
Thirty stents, varying in diameter from 4 mm to 12 mm and in length from 2 cm to 6 cm, were placed in the bile ducts of 10 microswine. After implantation, one-third of the animal subjects were killed at 2 months and the rest, at 6 months. All animals underwent premorbid cholangiography. Stents were pressure fixed, harvested, and encased in methacrylate. Specimens were then sectioned with a diamond saw, prior to staining. Individual specimens were photographed for visualization of the histologic reaction.


RESULTS
Technical success (implantation) was 100%. All stents were widely patent at 2-month and 6-month follow-up. Histopathologic study demonstrated a very thin epithelial hyperplasia that formed between stent wires. This did not cover the stent wires.


CONCLUSIONS
This new stent is safely implantable and demonstrates minimal tissue reaction in the biliary system of the swine, when compared with other metallic biliary stents.
Fontaine
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Department of Radiology, Ohio State University Medical Center, Columbus 43210, USA.
Dos Passos
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D000818:Animals; D017734:Bile Ducts, Extrahepatic / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D001672:Biocompatible Materials; D002758:Cholangiography; D004848:Epithelium / Q000473:pathology; D005500:Follow-Up Studies; D006965:Hyperplasia / Q000473:pathology; D013193:Stainless Steel; D015607:Stents; D013552:Swine; D013556:Swine, Miniature; D013635:Tantalum
D001672:Biocompatible Materials; D013193:Stainless Steel; D013635:Tantalum