Endovascular creation of an in vivo bifurcation aneurysm model in rabbits

PURPOSE: To develop a rabbit model of an intracranial bifurcation aneurysm to test new endovascular therapies. MATERIALS AND METHODS: An experimental aneurysm model was created in rabbit s by means of endovascular balloon occlusion of the left common carotid art ery, which created an aneurysm at the bifurcation formed by the aortic arch and the brachiocephalic trunk. A total of 18 aneurysms were created. In ei ght rabbits, the aneurysms were incubated with intraluminal elastase to ind uce degeneration of the elastic laminae. The animals were followed Up with angiography for as long as 3 months. The animals were sacrificed at various times, and histologic evaluation of the aneurysm was performed. RESULTS: Ten aneurysms created without elastase infusion were ail very smal l or completely closed at 1-3 months. Six aneurysms created with elastase i nfusion had long-term patency (two were patent at 1 month and four, at 3 mo nths). The elastase aneurysms had a mean width of 3 mm (range, 2-3.5 mm) an d a mean length of 5 mm (range, 3-7 mm). Histologic evaluation revealed des truction of the normal elastin layers, which allowed the artery to become a neurysmal. CONCLUSION: This aneurysm model re-created the hemodynamic forces and size of human cerebral bifurcation aneurysms and maintained the integrity of the endothelium. The creation of the aneurysms was rapid, reliable, and reprod ucible.