Endovascular Treatment Strategy and Clinical Outcomes for Ruptured Blood Blister-Like Aneurysms of the Internal Carotid Artery Using Low-Profile Visualized Intraluminal Support Stent

OBJECTIVE: It is challenging to safely treat blood blisterelike aneurysms (BBAs) of the internal carotid artery. Endovascular surgery has been reported, but the optimal strategy is yet to be established. We report our endovascular treatment strategy using the Low-profile Visualized Intraluminal Support (LVIS) stent. METHODS: Twelve patients with ruptured BBAs including 1 patient with 2 separate aneurysmal bulges were treated from December 2017 to January 2020. Single LVIS stent-assisted coil embolization was performed as the initial treatment. If the coil could not be placed in the aneurysm, or follow-up angiography showed persistent filling or regrowth of the aneurysm, a second LVIS stent was deployed as an overlapping stent. Clinical characteristics, treatment details, and clinical outcomes were retrospectively examined. RESULTS: Single stent-assisted coiling was performed in 8 patients (69%), 2 overlapping stents with coiling in 1 (8%), a single stent in 2 (15%), and 2 overlapping stents in 2 (15%). Three patients with persistent filling or regrowth of the aneurysm were re-treated with overlapping stents. Follow-up angiography confirmed complete occlusion in 12 aneurysms (92%). No re-rupture occurred. Postoperative symptomatic ischemia was confirmed in 4 patients (33%), and all 4 patients suffered severe subarachnoid hemorrhage. Modified Rankin scale was 0-2 in 8 patients (67%). CONCLUSIONS: LVIS stent-assisted coil embolization is effective in preventing re-rupture of BBAs. However, the morphology of the aneurysm may change within a short period, so careful angiographic follow-up is needed. Appropriate preoperative antiplatelet administration and optimal timing of the treatment may reduce the risk of postoperative ischemic complication.