Occlusion of experimentally created fusiform aneurysms with porous metallic stents

BACKGROUND AND PURPOSE: Carotid fusiform aneurysms are most commonly treate d with occlusion of the parent vessel. The purpose of our study was to asse ss the effectiveness of self-expanding, cobalt-alloy stents in the ablation of experimental fusiform aneurysms with preservation of the parent vessel in a carotid artery model, METHODS: Porous metallic stents were placed endovascularly along the length s of experimentally created fusiform aneurysms in the carotid arteries of d ogs; aneurysms were also created in the animals' opposite carotid arteries to serve as controls. RESULTS: Before stent placement, angiography of the carotid arteries showed large fusiform aneurysms along the lengths of the common carotid arteries and complex patterns of flow, Immediately after stent placement there was d isruption of the usual flow patterns within the lumens of the fusiform aneu rysms, The lumen between the wall of the aneurysm and stented carotid showe d stasis of contrast material and blood. Near-complete ablation of all aneu rysms was observed 8 weeks after stent placement. The stented carotid arter ies remained widely patent; control aneurysms and carotid arteries were pat ent and unchanged, Histopathologic analysis revealed fibrotic reactive scar tissue filling the space between the stent wires and outer wall of the fus iform aneurysm. CONCLUSION: Changing blood flow dynamics within an aneurysm can promote thr ombus formation, The stent promotes stasis and thrombus within the residual lumen between the stent wall and the outer wall of the aneurysm because it s woven wire mesh interferes with usual blood how patterns, which then prom otes formation of thrombus and fibrosis within the residual aneurysmal lume n.