Mechanical thrombectomy failure in anterior and posterior circulation stroke: current results from a high-volume comprehensive center.

Background: Mechanical thrombectomy (MT) is an established therapy for acute ischemic stroke (AIS), but recanalization is not always achieved. Common reasons are inadequate removal at the thrombus site and difficulties with the access route. In order to identify risk factors for MT failure we conducted a retrospective study on a high-volume comprehensive stroke center.

Methods: Evaluation of 552 thrombectomies (2019-23; anterior and posterior circulation, direct aspiration +/- stent retriever [SR]). MT failures (= modified Thrombolysis in Cerebral Infarction score 0 or 1) were analyzed for age, sex, pre- and post-MT modified Rankin Scale, bridging intravenous thrombolysis (IVT), occlusion site (anterior / posterior circulation, proximal / distal), the Kaesmacher classification and time trend results.

Results: MT failure occurred in 56 patients (10.1%; median age 76; 53.6% female). Nineteen (33.9%) patients received IVT (p = 0.326). Logistic regression analysis did not show a significant association of age, sex or occlusion site with MT failure (p = 0.165, p = 0.738, p = 0.838). Distal MT generally demonstrated lower success rates (p < 0.01). According to the Kaesmacher classification SR failure was the most frequent cause of MT failure (category 2B: 48%, p < 0.001). Time trend analysis suggests improving recanalization rates in the further course (4 times in year-on-year comparison; p < 0.01).

Conclusion: MT failure occurs in AIS treatment, even in high-volume centers and occurs more frequently in distal occlusions. Improvements in device technology, particularly SR, and ongoing refinements in access route selection offer the prospect of better outcomes in the future.