Proximal migration and compaction of an Enterprise stent into a coiled basilar apex aneurysm: a posterior circulation phenomenon?

A patient with a giant partially thrombosed basilar apex aneurysm was treated with balloon-assisted coil embolization. At the conclusion of the embolization, an Enterprise stent was placed from the upper basilar artery to the left P1 segment. Follow-up angiography 4 months later showed that the distal stent had pulled out of the posterior cerebral artery and was in the coil mass within the aneurysm. Angiography clearly showed that the stent had migrated down the basilar artery and that the artery was now kinked proximal to the stent. Nonetheless, the left posterior cerebral artery and the basilar artery were still widely patent. This is the first documented case in which a stent 'compacted' into a completed coiled aneurysm in a delayed fashion.