OBJECTIVETo evaluate the safety and short-term efficacy of Willis covered stent for treatment of blood blister-like aneurysms (BBA).

METHODSEight patients with BBA were treated with Willis covered stent system during the period from December 2014 to February 2016. The guiding catheter was placed as high as possible to facilitate the delivery of the covered stent system.

RESULTSs Nine covered stents were implanted in the aneurysms of 8 patients (8 aneurysms), and 8 stents were released successfully in the parent arteries. In 6 patients, angiography immediately after stent release showed complete disappearance of the aneurysm and the parent arteries remained patent. One patient experienced a minor endoleak after stent implantation, and another stent was implanted to eliminate the endoleak. Iatrogeniccarotid-cavernous fistula occurred in 1 patient due to tortuosity of the parent artery, for which superficial temporal artery-to-middle cerebral artery bypass combined with parent artery occlusion was performed instead; the patient recovered smoothly and the bypass remained patent at 6 months after the operation. No other periprocedural complications occurred in these patients. Follow-up study showed no new-onset neurological deficits in these 8 patients, who had mRS score of 0 in 6 patients and of 1 in 2 patients. Digital subtractive angiography at 6 months after the operation demonstrated no aneurysm in these patients, and only one patient showed mild stenosis in the parent artery.

CONCLUSIONWillis covered stents are effective for treatment of BBA with good safety and short-term outcomes.