Endovascular Thrombectomy for Large Ischemic Core Stroke: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract

Background and objectives: The optimal management of acute ischemic stroke (AIS) patients with large vessel occlusion and large ischemic core is uncertain. We aimed to evaluate the safety and efficacy of endovascular thrombectomy (EVT) compared with best medical treatment (BMT) for AIS through a study-level meta-analysis and meta-regression of 6 randomized controlled trials (RCTs).

Methods: PubMed, Embase, and the Cochrane databases were searched from January 1, 1980, to June 30, 2024. We limited search results to RCTs which compared EVT vs BMT among large-core AIS. The Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline was used for abstracting and assessing data quality and validity. The risk ratio (RR) with 95% CI was used to measure the association of EVT vs BMT with outcomes. Univariable meta-regression analyses were conducted to evaluate possible moderating effects of onset to randomization time (OTR) on outcomes when comparing EVT with BMT. The primary outcome was the 90-day ordinal modified Rankin Scale (mRS). Secondary outcomes were independent ambulation (mRS 0-3) at 90 days, and symptomatic intracranial hemorrhage (sICH) and mortality at 90 days.

Results: Six RCTs comprising 1,887 patients with large core AIS were included. Pooled results showed that EVT compared with BMT was associated with improved mRS score at 90 days (generalized OR, 1.6, 95% CI 1.4-1.8) and higher odds of independent ambulation (RR 1.9; 95% CI 1.5-2.5). Although the risk of sICH was higher in the EVT group (RR 1.7; 95% CI 1.1-2.7), there was a reduction in mortality in the EVT group (RR 0.9; 95% CI 0.8-1.0). Meta-regression showed that the benefit of EVT decreased with the extension of OTR (mRS 0-3, regression slope, -0.11, 95% CI -0.12 to -0.10; mRS 0-2, regression slope, -0.15, 95% CI -0.16 to -0.14). For patients with Alberta Stroke Program Early CT Score (ASPECTS) 0-2, EVT was associated with increased 90-day mRS 0-3 (RR 2.1, 95% CI 1.4-3.3) and mRS 0-2 (RR 2.8, 95% CI 1.2-6.7).

Discussion: EVT improved clinical outcomes among patients with large-core AIS assessed by ASPECTS of 3-5 or volumetric methods. Patients with ASPECTS 0-2 also had benefit from EVT and require further study. These results support expansion of the routine application of EVT.