Outcomes and Complications of Endovascular Mechanical Thrombectomy in the Treatment of Acute Posterior Circulation Occlusions: A Systematic Review

Background The use of thrombectomy in the treatment for acute ischemic stroke (AIS) affecting the anterior circulation is well established. Comparatively, fewer data exist on the effectiveness of these techniques in treating posterior circulation occlusions. This review analyzes and reports on the usefulness and outcomes of emergent thrombectomy in large-vessel occlusions affecting the posterior circulation. Methods A literature review was performed to identify all studies of patients with AIS in the posterior circulation who underwent endovascular mechanical thrombectomy (EMT) with stent retrievers and/or aspiration devices that were reported between January 1, 2015 and February 12, 2019. Favorable outcomes were defined as a modified Rankin Scale (mRS) score 0–2 at 3 months follow-up. Successful reperfusion was defined as modified Thrombolysis in Cerebral Infarction score of 2b–3. Results Twenty-five studies, comprising 1612 EMT-treated patients with posterior circulation AIS, were included in this analysis. The median presenting National Institutes of Health Stroke Scale score was 20.9 (range, 10.5–34). Favorable outcomes at 3 months follow-up were observed in 38% of patients (range, 16%–75%) and a mortality of 30% (range, 4%–64%). Successful reperfusion was achieved in 86% of cases (range, 62%–100%). Conclusions In patients with AIS caused by large-vessel occlusion of the posterior circulation, successful reperfusion can be achieved via EMT, with approximately a third of these patients achieving a good functional outcome. However, with similar proportions of treated patients experiencing significant morbidity or mortality, respectively, there is urgent need for additional studies to identify predictive or modifiable factors for a positive outcome.