Stent Retriever Thrombectomy Potentially Increases the Recanalization Rate, Improves Clinical Outcome, and Decreases Mortality in Acute Basilar Occlusion: A Systematic Review and Meta-Analysis

Background: Acute basilar artery occlusion (BAO) is a devastating condition if untreated. The optimal treatment strategy, however, is unknown. Historically, interventional approaches have been favored over intravenous thrombolysis (IVT), although this is not supported by good evidence. The aim of this systematic review and meta-analysis was to summarize and compare the results for treatment modalities of BAO, namely, IVT and interventional stent retriever thrombectomy (SRT). Methods: Studies on IVT and SRT in BAO were systematically searched. Successful recanalization (TICI >= 2b), favorable clinical outcome (modified Rankin Scale score <= 2), mortality, and the rate of symptomatic intracranial hemorrhage (SICH) were the target parameters. Only studies with >= 15 patients were included. IVT prior to SRT was allowed. Studies were excluded (1) if >1 thrombectomy device was used in >50% of the patients and (2) when data on outcome or treatment could not be parsed (e.g. registries). Odds ratios (ORs) were calculated using Mantel-Haenszel risk ratio estimation. Results are given as OR and the 95% confidence interval (95% CI). The chi(2) test was used to compare the outcome parameters clinical outcome, recanalization, mortality, and SICH. Results: A total of 17 studies (4 on IVT and 13 on SRT) with a total of 672 patients (IVT, n = 314; SRT, n = 358) were identified. Cumulatively, we found a highly significantly improved clinical outcome (43 vs. 31%, p = 0.004, OR [95% CI] = 1.66 [1.21, 2.76]), increased recanalization rate (88 vs. 60%, p < 0.00001, OR [95% CI] = 3.99 [2.73, 5.84]), and decreased mortality (26 vs. 41%, p = 0.0004, OR [95% CI] = 1.86 [1.33, 2.61]), as well as an equal rate of SICH (5 vs. 7%, p = 0.15, OR [95% CI] = 1.68 [0.82, 3.43]), in patients treated with SRT compared to those treated with IVT alone. Conclusions: The data from this meta-analysis suggest a possible superiority of SRT over IVT, pending positive results of randomized controlled trials. According to international recommendations, patients with BAO should preferentially be treated with SRT; if no contraindications exist, IVT should not be withheld.