Posterior Circulation Ischemia in the Endovascular Era.

Background And Objectives: To perform literature review of clinical, radiographic, and anatomical features of posterior circulation ischemia (PCI) and systematic review of the literature on the management of basilar artery occlusion (BAO) and associated outcomes.

Methods: Review of literature was conducted to identify publications describing the risk factors, etiology, clinical presentation, and imaging for PCI. A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. PubMed and Ovid MEDLINE were searched from 2009 to 2020 for articles relating to management of BAO. A synthesis was compiled summarizing current evidence on management of BAO.

Results: PCI accounts for 15%-20% of strokes. Risk factors are similar to anterior circulation strokes. Dizziness (47%), unilateral limb weakness (41%), and dysarthria (31%) are the most common presenting symptoms. A noncontrast head CT will identify PCI in 21% of cases; diffusion-weighted MRI or CT perfusion increase sensitivity to 85%. Recent trials have shown endovascular therapy can achieve >80% recanalization of BAO. In select patients, 30%-60% who receive endovascular treatment can achieve favorable outcome vs without. A total of 13% achieve good outcome and there is an 86% mortality rate.

Discussion: PCI can present with waxing and waning symptoms or clinical findings that overlap with stroke mimics and anterior circulation ischemia, making diagnosis more heavily dependent on imaging. Recanalization is an important predictor of improved functional outcome and survival. In this endovascular era, trials of BAO are fraught with deterrents to enrollment. Despite limitations, endovascular treatment has shown improved outcome in select patients.