Endovascular thrombectomy in acute stroke with a large ischemic core: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND: Endovascular thrombectomy (EVT) is the standard treatment for acute ischemic stroke due to internal carotid artery (ICA) or middle cerebral artery (MCA) M1 occlusion with a small ischemic core. However, the effect of EVT on acute stroke with a large ischemic core remains unclear. This study aimed to evaluate the association of EVT plus medical care versus medical care alone with outcomes in patients with acute stroke and a large ischemic core due to ICA or MCA M1 occlusion. METHODS AND FINDINGS: PubMed, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov were searched from January 1, 2000 to September 25, 2024. There were no language restrictions. Randomized controlled trials (RCTs) of patients with acute stroke and a large ischemic core that compared EVT plus medical care versus medical care alone were evaluated. We computed the random-effects estimate based on the inverse variance method. Risk ratio (RR) with 95% confidence interval (CI) was used to measure outcomes of EVT plus medical care versus medical care alone. The primary outcome was functional independence, defined as modified Rankin Scale (mRS) of 0-2 at 90 days post-stroke; and the lead secondary outcome was reduced disability, defined as ordinal shift of mRS. Safety outcomes were requiring constant care or death (mRS 5-6), death, and early symptomatic intracranial hemorrhage (sICH). Grading of Recommendations Assessment, Development and Evaluations (GRADE) was used to evaluate summaries of evidence for the outcomes. We included six RCTs comprising 1870 patients (826 females 44.2%) with acute stroke and a larger moderate or large ischemic core due to ICA or MCA M1 occlusion. All patients were nondisabled before stroke. Pooled results showed that at 90 days post-stroke, EVT plus medical care, compared with medical care alone, was associated with greater functional independence (RR 2.53, 95% CI 1.95, 3.29; p < 0.001; number needed to treat NNT, 9, 95% CI 6,15) and reduced disability (common odds ratio 1.63, 95% CI 1.38, 1.93; p < 0.001; NNT, 4 minimum possible NNT, 2; maximum possible NNT, 6). EVT plus medical care, compared with medical care alone, was associated with a lower risk of requiring constant care or death (RR 0.74, 95% CI 0.66, 0.84; p < 0.001; NNT, 7, 95% CI 6,11). EVT plus medical care, compared with medical care alone, was associated with a nonsignificantly higher proportion of patients with early symptomatic intracranial hemorrhage (RR 1.65, 95% CI 1.00, 2.70; p = 0.05). The rates of death were not significantly different between the EVT plus medical care and medical care alone groups (RR 0.86, 95% CI 0.72, 1.02; p = 0.08). Main limitations include variability in imaging definitions of large core and inclusion of both larger moderate and large cores in the analysis. CONCLUSIONS: Among patients with acute stroke and a larger moderate or large ischemic core due to ICA or MCA M1 occlusion who were nondisabled before stroke, EVT plus medical care, compared with medical care alone, may be associated with improved functional independence, reduced disability, and reduced rates of severe disability or death at 90 days post-stroke. PROSPERO registration number: CRD42024514605.