Endovascular thrombectomy without versus with intravenous thrombolysis in acute ischemic stroke: a non-inferiority meta-analysis of randomized clinical trials

OBJECTIVE: To conduct a meta-analysis of randomized trials to comprehensively compare the effect of endovascular thrombectomy (EVT) versus intravenous thrombolysis (IVT) plus EVT on functional independence (modified Rankin Scale (mRS) 0-2) after acute ischemic stroke due to large vessel occlusions (AIS-LVO). METHODS: We searched Pubmed, EMBASE, CENTRAL, and clinicaltrials.gov from January 2000 to February 2021 and abstracts presented at the International Stroke Conference in March 2021 to identify trials comparing EVT alone versus IVT plus EVT in AIS-LVO. Five non-inferiority margins established in the literature were assessed: -15%, -10%, -6.5%, -5%, and -1.3% for the risk difference for functional independence at 90 days. RESULTS: Four trials met the selection criteria, enrolling 1633 individuals, with 817 participants randomly assigned to EVT alone and 816 to IVT plus EVT. Crude cumulative rates of 90-day functional independence were 46.0% with EVT alone versus 45.5% with IVT plus EVT. Pooled results showed the risk difference of functional independence was 1% (95% CI -4% to 5%) between EVT alone versus IVT plus EVT. The lower 95% CI bound of -4% fell within the non-inferiority margins of -15%, -10%, -6.5%, and -5%, but not -1.3%. Pooled results also showed the risk difference between EVT alone versus IVT plus EVT was 1% (95% CI -3% to 5%) for mRS 0-1, and 1% (95% CI -1% to 3%) for symptomatic intracranial hemorrhage. CONCLUSIONS: This meta-analysis suggests that EVT alone is non-inferior to IVT plus EVT for several, but not the most stringent, non-inferiority margins.