Creation of 6-10mm Diameter Transjugular Intrahepatic Portosystemic Shunts Using a Novel TIPS Stent Graft in a Swine Model.

Purpose: To assess the delivery, function, and patency of a new expanded polytetrafluoroethylene encapsulated TIPS stent- graft ("Liverty") in an animal model.

Materials and methods: TIPS were created in 2 successive groups: 14 single & 10 overlapping devices, in swine weighing 52-64kg. Explants occurred at 30 (n=10) and 60 (n=14) days. These were evaluated by histomorphometry and histopathologic evaluations, and electron microscopy.

Results: Seven 6mm, five 7mm, and twelve 10mm diameter TIPS were created using varied human TIPS access sets without complications; both sheathed and unsheathed advancement and deployment of the devices within liver tracts. One animal was sacrificed at 35d due to encephalopathy; remainder survived to endpoints. 22/24 TIPS were patent at 30 and 60-day endpoints; Mean stenosis at 30 days was 13.3% +/- 10.1%, and for 60 days was 18.44% ± 5.04%. Two shunts were occluded by tissue overgrowth at unstented native hepatic vein end and downgrowth into TIPS. Histology and electron microscopy showed well-apposed, incorporated devices lined with smooth, uniform neointimal tissue averaging 0.48mm (single devices) and 0.74mm thick (overlapped devices) with minimal adventitial inflammation.

Conclusion: The new Liverty TIPS stent graft was straightforward to deploy for TIPS creation and resulted in patent 6,7, and 10mm diameter shunts in both single and overlapping configurations. One- and 2-month histology showed desired tissue healing without in-stent stenosis.