Endovascular isolation of intracranial blood blister-like aneurysms with Willis covered stent.

Objective: Intracranial blood blister-like aneurysm (BBA) is a rare type of aneurysm that lacks all layers of the arterial wall. These fragile aneurysms have the propensity to rupture with minimal manipulation, which makes them hazardous and difficult to treat. The present study evaluated the safety and feasibility of endovascular treatment of BBAs with the Willis covered stent.

Materials: Thirteen patients (7 men and 6 women, age range 28-68 years) who presented with ruptured BBAs and were treated with the Willis covered stent were retrospectively reviewed. Results of the procedures and treatment-related complications were recorded. Angiographic and clinical follow-ups were performed 4-6 months after the procedure.

Results: Placement of the covered stent was successful in all patients. Immediate angiography showed complete aneurysm occlusion in 12 patients while one patient showed a mild endoleak. This high rate of aneurysm exclusion ensured the security of postoperative antiplatelet treatment. Occlusion of the ophthalmic artery occurred in two patients and occlusion of the anterior choroidal artery occurred in one patient; however, none of them showed acute or delayed clinical symptoms. Thrombosis, aneurysm rupture, and other complications did not develop in any case. Angiographic follow-up showed complete aneurysm exclusion without aneurysm recurrence in any patients. Only two patients showed asymptomatic mild to moderate in-stent stenosis. All patients had satisfactory clinical outcomes (modified Rankin Scale score ≤1).

Conclusions: Willis covered stent implementation may be safe and feasible for BBAs. This strategy might be a promising option for this high-risk type of aneurysm.