Mechanical Thrombectomy Improves Functional Outcomes Independent of Pretreatment with Intravenous Thrombolysis

Abstract

Background and Purpose - Endovascular intervention for emergent large-vessel occlusion (ELVO) has evolved rapidly during the past decade. The question of whether pretreatment with intravenous thrombolysis (IVT) has a significant impact on the functional outcome of patients with ELVO still remains unanswered. Methods - We conducted a systematic review and meta-analysis of all available randomized controlled trials evaluating the efficacy of endovascular therapy (ET) for acute ischemic stroke. We performed a mixed-effects subgroup analysis of the reported odds ratios on the association of ET (versus standard therapy) with 3-month functional outcome, stratified by pretreatment with IVT. Results - Six randomized controlled trials were included, comprising 1916 total patients (49.1% receiving ET with IVT pretreatment and 5.6% receiving ET without IVT pretreatment). In the subgroup analysis, ET was associated with a higher likelihood of better 3-month functional outcome in both the subgroup of patients with (odds ratio=1.83; 95% confidence interval, 1.37-2.44; P<0.001) and without (odds ratio=2.47; 95% confidence interval, 1.32-4.63; P=0.001) pretreatment with IVT. We documented no significant effect of IVT pretreatment on the 3-month functional outcome of patients with ELVO undergoing ET, suggesting that ET is effective in all patients with ELVO. Heterogeneity was documented in the IVT pretreatment subgroup (I2=68.3%; P for Cochran Q=0.014), but not in the subgroup that did not receive IVT pretreatment (I2=0%, P for Cochran Q=0.927). The risk of bias was considered to be generally low in the qualitative assessment of the included trials. Conclusions - Our observation provides evidence and further reassurance to stroke clinicians regarding the efficacy of ET in ELVO independent of pretreatment with IVT.