Efficacy and safety of mechanical thrombectomy beyond 24 to 72 hours in acute ischemic stroke patients with large vessel occlusion

ObjectiveTo evaluate the efficacy and safety of mechanical thrombectomy performed beyond 24 hours from symptom onset in patients with acute ischemic stroke (AIS) and large vessel occlusion (LVO).MethodsIn this retrospective cohort study, patients with LVO-related AIS who underwent mechanical thrombectomy within 72 hours of onset were enrolled from the Acute Stroke Patients for Stroke Management Quality Evaluation online database (CASE-Ⅱ, NCT04487340) between January 2017 and December 2024. Patients were stratified into beyond 24-hour thrombectomy group and within 24-hour thrombectomy group based on the time from onset to mechanical thrombectomy. Propensity score matching (PSM) was used to balance baseline characteristics between the two groups. Binary logistic regression and generalized linear models were employed to compare 3-month functional and safety outcomes between the groups. Sensitivity analyses were conducted separately in patients undergoing mechanical thrombectomy within the extended time window (6-24 hours) and in those receiving mechanical thrombectomy alone (without prior intravenous thrombolysis). Subgroup analyses were performed based on age, presence of atrial fibrillation, use of oral anticoagulants, pre-stroke modified Rankin Scale (mRS) score, baseline National Institutes of Health Stroke Scale (NIHSS) score, and occlusion site.ResultsOf the 9121 patients included, 277 underwent mechanical thrombectomy beyond 24 hours and 8844 within 24 hours. After PSM, 534 patients were analyzed (267 per group). No significant difference was found in the rate of 3-month functional independence (mRS score 0-2) between the beyond 24-hour and within 24-hour thrombectomy groups, both before and after matching (OR=0.977, 95%CI: 0.753-1.268, P=0.861; OR=1.151, 95%CI: 0.712-1.549, P=0.804, respectively). The rates of 24-hour symptomatic intracranial hemorrhage, 24-hour parenchymal hemorrhage, and 3-month all-cause mortality also showed no significant differences between the two groups (all P>0.05). Sensitivity analyses among patients in the extended time window (6-24 hours) and those receiving mechanical thrombectomy alone yielded similar results, with no significant differences in functional or safety outcomes (all P>0.05). Subgroup analyses revealed no significant heterogeneity in the 3-month functional independence across various baseline characteristics (all P>0.05).ConclusionFor AIS patients with LVO, the efficacy and safety of mechanical thrombectomy performed beyond 24 hours appear comparable to those of mechanical thrombectomy performed within 24 hours.