Abstract
BACKGROUND: Endovascular therapy (EVT), including mechanical thrombectomy and intraarterial thrombolysis, is increasingly applied in patients with acute ischemic stroke caused by distal medium vessel occlusions. However, its efficacy and safety in this specific population remain inconclusive. METHODS: We conducted a systematic review and meta-analysis of studies comparing EVT and non-EVT for distal medium vessel occlusion patients, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA). Data were extracted from PubMed, Embase, and Cochrane Library up to February 16, 2025. The primary efficacy outcomes were excellent (90-day modified Rankin Scale score, 0-1) and functional independence (90-day modified Rankin Scale score, 0-2), while safety outcomes included symptomatic intracranial hemorrhage and 90-day mortality. RESULTS: A total of 30 studies (4 randomized controlled trials, 23 cohort studies, 3 case-control studies) involving 9210 patients were included in the meta-analysis, with 48.2% patients receiving EVT. No significant improvement was observed in excellent outcome (odds ratio, 0.98 [95% CI, 0.89-1.07]) or functional independence (odds ratio, 0.99 [95% CI, 0.90-1.08]) in patients receiving EVT compared with non-EVT. However, EVT was associated with higher risks of symptomatic intracranial hemorrhage (odds ratio, 1.79 [95% CI, 1.45-2.20]) and mortality (odds ratio, 1.40 [95% CI, 1.21-1.63]). Subgroup analysis revealed that patients with medium anterior circulation occlusions achieved higher odds of efficacy outcomes, while those with posterior circulation occlusions experienced higher risks of symptomatic intracranial hemorrhage and mortality and lower odds of efficacy outcomes. CONCLUSIONS: EVT demonstrates significant efficacy in patients with medium anterior circulation occlusions (M2, A1) without additional safety risks. However, its benefit in distal anterior circulation occlusions remains uncertain, and EVT in posterior circulation occlusions (P1, P2, P3) is associated with higher risks and lower efficacy assessed by the modified Rankin Scale. Further randomized controlled trials focusing on distal and anterior cerebral artery occlusions are warranted to clarify these findings. The conclusions were mainly based on observational studies. REGISTRATION: URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42025643022.