Abstract 11722: Excellent Preclinical Results of Honeycomb Microporous Covered Stents for the Treatment of Large and Wide-Necked Cerebral Aneurysms

Background: We developed covered stents with a microhoneycomb mesh for the treatment of large or giant wide-necked cerebral aneurysms. These aneurysms are extremely difficult to treat and carry high risks, even with the use of clinically available surgical methods or the endovascular technique using coils with the assistance of bare stents. This preclinical study confirmed the excellent performance of our stents in three animal experimental models. Methods and Results: The covered stents were prepared by using balloon-expandable stents (CoCr; diameter, 3.5-5.0 mm; length, 16-28 mm) and by dip coating to cover their struts completely with a polyurethane membrane (thickness, 20 μm), followed by laser microprocessing (pore size, approximately 100 μm; opening ratio, approximately 30%). Model 1: In prepared tortuous canine arteries (n = 12) that simulated the shape of the human internal carotid artery, all stent-mounted delivery catheters could smoothly navigate with little arterial damage. Model 2: In a prepared canine model (n = 10) of large (over 7 mm), wide-necked (over 4 mm) outer-sidewall aneurysms, at 3 months after stenting, completely endothelialized neointima was formed at the aneurysm openings and the aneurysm sacs were entirely organized. Model 3: In rabbit branching abdominal aortas, the vascular flow pattern at all the branching arteries remained unchanged for over 1 year, even after performing overlap stenting (n = 5) in addition to single stenting (n = 5). On all the stented luminal surfaces, complete thin neointimal formation with complete endothelialization was observed. Conclusion: Our newly developed novel covered stents exhibited excellent preclinical performance in three animal experimental models in terms of stent delivery, aneurysm embolization, and flow maintenance in branching arteries. We highly expect that the stents will be useful as endovascular embolization devices for large and wide-necked aneurysms in humans.