Preclinical Efficacy and Safety Evaluation of a Novel Controlled‐Expansion ePTFE‐Covered TIPS Stent in a Swine Model

Aims Conventional fixed‐caliber transjugular intrahepatic portosystemic shunt (TIPS) stents may limit individualized portal decompression and lead to over‐ or under‐shunting. We therefore aimed to evaluate the safety and performance of a novel controlled‐expansion expanded polytetrafluoroethylene (ePTFE)‐covered TIPS stent, which is designed for precise placement, secure anchoring, and on‐demand diameter adjustment. Methods Eleven healthy swine (40–50 kg) underwent TIPS with a self‐expanding nitinol stent‐graft comprising a covered intrahepatic segment and an uncovered portal segment, with balloon‐calibrated diameter adjustment across 6.0–10.0 mm; all stents were post‐dilated to a fixed 8.0‐mm functional diameter. Animals were assigned to 1‐ ( n = 3), 3‐ ( n = 3), or 6‐month ( n = 5) endpoints. Patency was defined as < 50% diameter stenosis without angiographic occlusion. Patency and integrity were assessed by digital subtraction angiography with quantitative vascular angiography (QVA). Systemic and local responses were evaluated by clinical monitoring, hematology/serum biochemistry, comprehensive necropsy, and blinded histopathology. Results Technical success rate was 100% in all 11 cases, with no intraoperative complications; all animals survived to endpoint. Deployment, visibility, and handling were consistently excellent. Follow‐up angiography showed patent shunts without migration, thrombosis, or fracture; no collapse, kinking, or ePTFE delamination. QVA demonstrated mild luminal loss: mean diameter stenosis was 4.88 (3.13–7.19)% at 1 month, 9.93 (7.30–14.09)% at 3 months, and 13.41 (12.05–16.05)% at 6 months; all shunts showed < 30% stenosis. Laboratory values remained within or returned to normal limits. Necropsy confirmed well‐incorporated tracts without device‐related pathology. Histology showed complete endothelialization, a thin neointima with minimal inflammation, and absence of thrombosis at all time points. Conclusions In healthy swine, this stent demonstrated favorable safety and patency; performance in portal hypertension remains to be established. This adjustable‐caliber design may help overcome some limitations of fixed‐diameter stents and supports further evaluation in disease models and humans.