LAUSR

OBJECTIVES To perform a systematic review and meta-analysis to investigate pre-treatment collaterals and outcomes of mechanical thrombectomy in patients with acute ischemic stroke of large vessel occlusion in anterior circulation. METHODS We systematically searched EMBASE, PubMed and the Cochrane Library from their dates of inception to March 5, 2020, and also manually searched reference lists of relevant articles. Pooled relative risk with 95% confidence interval on the association between good collaterals and functional independence (in term of mRS 0-2), symptomatic intracranial hemorrhage, mortality and successful reperfusion were synthesized using a random-effects model. RESULTS Thirty-four studies enrolling 5768 patients were included in analysis. Good collaterals was significantly associated with functional independence (RR 1.93, 95%CI 1.64-2.27, P<0.0001), successful reperfusion (RR 1.23, 95%CI 1.12-1.35, P<0.0001), decreased rate of symptomatic intracranial hemorrhage (RR 0.68, 95%CI 0.47-0.97, P=0.032) and mortality (RR 0.37, 95%CI 0.27-0.52, P<0.0001). The results were consistent in sensitivity analysis. The associations between good collaterals and reperfusion remained stable after adjusting for publication bias. CONCLUSIONS Pre-treatment good pre-treatment collaterals were associated with functional independence, successful reperfusion and decreased rate of sICH and mortality after receiving mechanical thrombectomy in patients with acute ischemic stroke of large vessel occlusion.