TIPS Intraoperative Bile Leakage Its Restenosis

Transjugular Intrahepatic Portosystemic Shunt In a Porcine Model: Histological CharacteristicsPurpose: To understand and alter the high incidence of restenosis after TIPS, an animal model would be helpful, but would require histologic similarity to human findings. Previously established animal models have not provided detailed descriptions of their histological characteristics. We , therefore, systematically evaluated the histological findings of experimental TIPS in a porcine model. Materials and Methods: TIPS was performed in 20 normal domestic pigs using a metallic stent. Pigs were sacrificed at 2-16 days post-TIPS procedure. All the TIPS shunts were examined by venography both immediately after placement of the stent and immediately before sacrifice. Representative histological sections from the portal, mid and hepatic regions of the stent were assessed using modified Giemsa and basic fuchsin stains. Anti-SMC alpha Actin stain was used to identify the smooth muscle cell component of the histologic section. Quantification of the proliferation reaction was performed using standard planimetry techniques and Micro-plan II image analysis system. Results: All pigs lived to the scheduled date of euthanasia post-TIPS, but for one death at 2 days. The stent was totally occluded or dysfunctional in 15 pigs(75%,partial patent in 4 (20%) and only one(5%) patent. Histologically, stent occlusion was primarily due to pseudointimal hepyplasia. Myofiborblastic proliferation was morphologically similar in all three assayed regions of the stent. Average thickness of proliferation and ratio of proliferlation/total area were 2.14 mm and 0.67, respectively. There was a mild fibrous and/or lymphocytic reaction surrounding the stent wires, and between the pseudointimal proliferation and liver. Marked ingrowth of bile ducts within the proliferation was noted in three specimens . Bacterial growth in clot within the stent occurred in 1 pig.Conclusion: Histological characteristics of the proliferative reaction in the TIPS porcine model are very similar to the proliferative response reported in humans, although the extent of the proliferation appears greater and develops more rapidly. This model seems optimal in investigation for mechanism of TIPS restenosis and related TIPS studies.Key Words: Portosystemic shunt stent; Porcine experimental; Pathohistology...