Abstract WP8: Determinants Of Benefit From Endovascular Recanalization In Acute Ischemic Stroke: A Meta-Analysis

Abstract

Background: While endovascular recanalization therapy for acute ischemic stroke has made substantial technical advance, demonstration of clinical benefit has to date been elusive. We performed a systematic meta-analysis of all clinical trials and large series of endovascular recanalization to identify features associated with good clinical outcome. Methods: We searched MEDLINE and Cochrane Registry of Clinical Trials to identify all randomized trials and large cohort series of endovascular recan for acute stroke published from 1999 - 2012. Reports were included if they used any endovascular recanalization technique in a sample of 50 or more subjects. Studies confined to patients with post circulation or ICA occlusions were excluded. Results: A total of 22 studies reporting 2185 patients met selection criteria. Interventions were intra-arterial fibrinolysis (IAF) in 6 series (467 patients), the Merci retriever in 5 (508 patients), the Penumbra system in 3 (373 patients), and stent retrievers in 5 (571 patients). Across series, average patient age was 66, 49% were female, median pretreatment NIHSS was 17, and avg time from onset to recanalization was 293 minutes. Target occlusion locations included the ICA in 17% and MCA in MCA 63%. Independent final clinical outcome (mRS ≤ 2 or nearest equivalent) was achieved in 41%, SICH occurred in 8%, and mortality rate was 23%. Factors associated with independent clinical outcome were: lower NIHSS pretreatment (r = 0.5), achievement of partial or better recanalization (r = 0.4), and onset to recanalization time (r =-0.4). A factor associated with mortality was longer time to recan (r = 0.4). With individual interventions, rates of good outcome were: IAF 51%, Merci 29%, Penumbra 32%, and stent retrievers 51%. Rates of mortality were: IAF 15%, Merci 33%, Penumbra 26%, and stent retrievers 22%. Conclusions: Independent clinical outcome after endovascular recanalization therapy is associated with lower pretreatment deficit severity, achievement of recanalization, and shorter time to recanalization. Differences in functional outcomes are noted between different endovascular recanalization techniques, likely reflecting differences in case mix and in recanalization efficiency.