Abstract 4145821: Serial Vascular Responses of Balloon-expandable Stent with Biodegradable Film-type Graft in a Rabbit Iliac Artery Dissection Model (BioGard Study)

Introduction and Background: Arterial dissection during endovascular therapy rarely occurs but can be lethal. A significant blood volume extravasation during coronary artery interventions is related to the very high mortality (20-30%). In this hyperacute emergent clinical situation, covered stents have been considered as a primary measure to prevent further serious arterial events. A fabric-based covered graft stents yield poor clinical outcomes. To overcome these challenges, the balloon-expandable stent with biodegradable film-type graft for treating arterial dissection was invented. Research Questions and Objectives: A novel balloon-expandable stent with biodegradable film graft for overcoming these issues would be valid for efficacy and safety in a rabbit iliac artery dissection model. Method and Approach: Eighteen iliac artery dissections were induced by balloon over-inflation on angiography (Ellis type 2 or 3) and treated using the test device (3.0 x 24 mm). Subsequently, twelve animals underwent histologic examinations and micro-computed tomography (CT) at 0, 2, 4, and 8 weeks and 3, 6, 9, and 12 months and angiography at one-year. Results and Data: There were no adverse cardiovascular events during the one-year. Early-stage histologic examination revealed complete sealing of disrupted vessels by the device, exhibiting mural hematoma, peri-stent red thrombi, and dense infiltration of inflammatory cells. Mid- and long-term histologic examination showed patent stents with neointimal hyperplasia over the stents (% area stenosis: 11.8 at 2weeks, 26.1 at 1month, 29.7 at 3months, 49.2 at 9months, and 51.0 at 1year), along with mild peri-strut inflammatory response (Grade: 1-2 at mid-term and 0-1 at long-term). The graft film became scarcely visible after six months. Both CT and angiography revealed no instances of thrombotic occlusion or in-stent restenosis (% diameter stenosis: 5.7 at 2weeks, 12.3 at 1month, 14.2 at 3months, 25.1 at 9months, and 26.6 at 1 year). Conclusion: The novel balloon-expandable stent with a biodegradable film graft demonstrates feasibility in managing severe artery dissection and preventing lethal vascular events in animal model. Future human studies are warranted to validate these findings and elucidate the clinical outcomes of the study.