Development of a Transfemorally Delivered Endovascular Graft for Treatment of Aortic Aneurysms in a Canine Model

Abstract

Advances in the treatment of atherosclerotic disease by transluminal angioplasty and intra-arterial stenting have led to the development of a transfemoral endovascular approach to the treatment of aortic aneurysmal disease. The authors investigated this technique using an endovascular graft employing self-expanding anchors for the exclusion of infrarenal aortic aneurysms. They investigated the technique of transfemoral endovascular aortic grafting in 13 male mongrel dogs weighing an average of 30 kg. Eleven animals had fusiform infrarenal aortic aneurysm models created. One week to three months after surgery all animals underwent midstream aortography under general anesthesia to examine aneurysm morphology. A 14 French catheter was introduced through the right common femoral artery, and under fluoroscopic guidance the endovascular graft was delivered in an infrarenal aortic position. Completion aortography was then performed to confirm placement. They tested two endovascular graft prototypes. The first employed a proximal anchor attached to the graft and a separately delivered distal anchor. Successful graft delivery was achieved in five of six attempts. Unsuccessful graft delivery occurred in 1 case because of an inability to negotiate aneurysm tortuosity. After delivery graft twisting occurred in 1 case and graft invagination occurred in 2 others upon the attempt to deliver the distal anchor. Successful exclusion was achieved in 3 of 4 remaining cases with an aneurysm model using this prototype. The second prototype employing proximal and distal anchors attached to the graft was successfully deployed in seven of seven attempts. Successful aneurysm exclusion was achieved in 5 of these 7 cases. Failure to exclude the aneurysm neck occurred in 2 cases. In this preliminary study the authors found the concept of endovascular delivery of a self-anchoring tube graft to be feasible. The optimal delivery system is flexible and possesses a small outer diameter to allow a transfemoral approach through moder ately tortuous iliac arteries. Accurate delivery is aided by intermittent fluoroscopic examination. Doubly anchored grafts are necessary to ensure aneurysm exclusion and prevent graft twisting. Self expanding anchors allow simple endovascular graft deploy ment in a single pass. Continued animal investigation into the fate of aortic side branches, distal embolization, and graft migration is necessary to ensure the eventual success of this technique.