PROTOTYPE STENT - IN-VIVO SWINE STUDIES IN THE BILIARY SYSTEM

PURPOSE: To evaluate the safety of implantation and the biocompatibili ty of a new balloon-expandable stent in the biliary system of the swin e model. MATERIALS AND METHODS: Thirty stents, varying in diameter fro m 4 mm to 12 mm and in length from 2 cm to 6 cm, were placed in the bi le ducts of 10 microswine. After implantation, one-third of the animal subjects were killed at 2 months and the rest, at 6 months, All anima ls underwent premorbid cholangiography. Stents were pressure fixed, ha rvested, and encased in methacrylate. Specimens were then sectioned wi th a diamond saw, prior to staining, Individual specimens were photogr aphed for visualization of the histologic reaction. RESULTS: Technical success (implantation) was 100%, All stents were widely patent at 2-m onth 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. CONCLUSION: This new stent is safely implan table and demonstrates minimal tissue reaction in the biliary system o f the swine, when compared with other metallic biliary stents.