Patency of perforating arteries after stent placement? A study using an in vivo experimental atherosclerosis-induced model.

BACKGROUND AND PURPOSE: The recent advent of flexible stents has enabled their application in intracranial atherosclerotic disease. However, it is unclear whether perforating artery occlusion occurs after stent placement in atherosclerotic stenotic vessels. We investigated this issue by using experimental atherosclerosis-induced rabbits. METHODS: A stainless steel balloon-expandable stent was deployed into the atherosclerosis-induced abdominal aorta across the lumbar artery in six New Zealand white rabbits. This model system is suitable because the diameter of the abdominal aorta is similar to that of human intracranial arteries. We evaluated the patency of the lumbar artery by using angiography and scanning electron microscopy (SEM) 3 months after stent placement. Histopathologic evaluation also was performed in one rabbit. RESULTS: The lumbar artery was patent in five of six rabbits per angiography. The lumbar artery was occluded with an intraluminal thrombus in one rabbit. However, SEM findings demonstrated that the stent struts were covered completely with a thick neointima and the ostium of the lumbar artery became narrowed in all cases. In the one lumbar artery that was occluded at angiography, histopathologic findings confirmed that intraluminal thrombus surrounded the stent struts crossing the ostium. CONCLUSION: We observed luminal narrowing after stent placement in an atherosclerotic stenotic vessel, although patency of the perforating arteries was generally maintained.