High-performance self-expanding stent graft: development and application to experimental aneurysms

Large or giant aneurysms in the craniocervical area with broad necks are of concern and are treated surgically, endovascularly, or in both ways. Surgically, their treatment is difficult, with relatively high risks. For their embolization, we have been developing a high-performance stent graft that has three characteristics: a thin and expandable segmented polyurethane (SPU) membrane, micropores formed by the excimer laser ablation technique, and a drug delivery system at the membrane. Stent grafts were fabricated using commercially available self-expanding stents. These stents were covered with a thin SPU membrane by the dip-coating method. Micropores were then formed by the excimer laser ablation technique and an argatroban coating was added. We tested the effectiveness of this new stent graft by treating experimental canine aneurysms. Experimental aneurysms were made in the bilateral carotid arteries of four female beagles by end-toside anastomosis using an autologous venous pouch. One month after aneurysm formation, the experimental aneurysm in one of the carotid arteries was covered with our self-expanding stent graft and the aneurysm in the other artery was covered with a bare self-expanding stent. On angiograms 1 month after stenting, the aneurysms treated with our stent graft were completely occluded without significant parent artery stenosis, but the aneurysms treated with the original bare stent were still open. Our high-performance self-expanding stent graft was easily applied to the experimental aneurysms and accomplished complete occlusion of aneurysms in beagles. Further study should be performed for the goal of clinical use.