Coincident intracranial aneurysm on the target vessel of acute ischemic stroke treated with mechanical thrombectomy: a multicentric case-control study

The presence of a coincident intracranial aneurysm (CIA) on the target vessel of patients undergoing mechanical thrombectomy (MT) for acute ischemic stroke (AIS) poses challenges, as the benefits and risks of the procedure in this scenario remain unclear. This study aimed to evaluate the efficacy and safety of MT in AIS cases with a CIA on the target vessel. We retrospectively analyzed data from 14 stroke centers in France and Switzerland between January 2015 and January 2023. We identified AIS cases with CIA on the target vessel treated with MT. The control population was constituted from the ETIS registry (Endovascular Treatment in Ischemic Stroke), including AIS patients treated with MT in the same centers during the same period, and were matched (1:4) on age (±1 year) and sex. The primary outcome was favorable functional status at 3 months, defined as a modified Rankin Scale (mRS) score ≤2 or equal to pre-stroke mRS. A total of 104 MT-treated patients with at least one CIA on the target vessel and 416 MT-treated patients without CIA were analyzed. Despite an aneurysm rupture occurring in 5.8% of cases, no significant differences were observed in favorable functional outcome at 3 months between the CIA and control groups (42.4% vs 41.0%; adjusted OR 1.20, 95% CI 0.72 to 1.97). Similarly, recanalization rates (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2b at end of MT) did not differ significantly (90.0% vs 85.9%; adjusted OR 1.75, 95% CI 0.77 to 3.95). MT is an effective option for AIS patients, even with CIA on the target vessel, but the risk of rupture underscores the need for procedural planning. Future studies should further explore size and location criteria to optimize patient selection and orientation.