Mechanical Thrombectomy for Large Vessel Occlusion Strokes Involving a Cerebral Aneurysm in the Target Vessel: Case Series

<b>Objective:</b> With the increasing prevalence of mechanical thrombectomy (MT) for large vessel occlusion strokes, encountering unruptured cerebral aneurysms (uANs) in MT target vessels has become more common, necessitating case accumulation to establish safety guidelines for MT in such cases. In this study, we aimed to review and present cases of uAN associated with MT target vessels at our hospital. <b>Methods:</b> Among 320 patients who underwent MT for large vessel occlusion strokes at our hospital between January 2018 and December 2021, we selected patients with uAN in the MT target vessel and analyzed various parameters including the occluded vessel, uAN location, timing of uAN discovery, thrombus retrieval procedures, materials, recanalization outcomes, and uAN rupture incidence. <b>Results:</b> Of the 320 patients, 7 had aneurysms in the target vessel (2.2%). The uANs were identified before the device crossed the occluded lesion (lesion crossing (LC)) in four cases, while in three cases, identification occurred after LC or recanalization. In 1 of the 3 cases, a uAN was suspected on preoperative computed tomography at the retrospective review. The thrombectomy procedures included a direct aspiration first pass technique (ADAPT) alone in one patient, stent retrieval (SR) alone in two patients, combination therapy in three patients, and SR combined with local infusion of urokinase in one patient. The effective recanalization rate, defined as TICI 2b or 3, was 57.1% (4/7). The average puncture-to-recanalization time was 77.4 min, and there were no instances of uAN rupture associated with MT. <b>Conclusions:</b> We presented seven cases of uAN in the MT target vessel. No uAN rupture was associated with MT, although the same strategies and techniques of routine MT at our hospital were employed, prioritizing recanalization. Preoperative image assessment considering the possibility of a uAN being present in the MT target vessel is more essential, as well as careful selection of MT procedures according to the situation of each patient.