Objective To elucidate the topic a literature review of clinical, radiographic and anatomical features of posterior circulation ischemia (PCI) was summarized, and systematic review of the literature on the management of basilar artery occlusion (BAO) and associated outcomes was performed.

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 Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement.¹ Pubmed and Ovid MEDLINE were searched from 2009-2020 for papers relating to management of BAO.  A synthesis was compiled summarizing current evidence on management of BAO.

Results PCI account for 15-20% of strokes.  Risk factors are similar to anterior circulation strokes.  Dizziness (47%), unilateral limb weakness (41%), and dysarthria (31%) are most common presenting symptoms.  A non-contrast 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% that receive endovascular treatment can achieve favorable outcome versus without 13% achieve good outcome and 86% mortality rate.

Conclusion 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.

To elucidate best management of acute BAO in an endovascular era of newer generation MT devices, a systematic review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines (Figure 6).¹  Pubmed and Ovid MEDLINE were searched from January 2009 to October 2020 for papers relating to management of BAO using search criteria BA, treatment and stroke. Previous meta analyses, RCT, systematic reviews and case series with more than 5 cases were included. Papers about pediatric population, isolated VA occlusion, VA stenosis treated with angioplasty and stenting for nonacute strokes, expert opinions and study protocols (except for one RCT near completion) were not included. A synthesis was compiled summarizing the current evidence regarding management of acute BAO.

After removal of duplications, the initial search revealed 440 articles, of which 58 studies were related to acute BAO management.  Thirty-seven publications^58-94 and 1 RCT which reported results at an international meeting May 13, 2020 (publication pending)⁹⁵ met the final inclusion criteria.  Seven systematic reviews or meta-analyses and 2 reviews of the literature on the subject were included to identify articles that may have been missed during the literature review.  Two studies were RCTs comparing IVT vs IVT plus endovascular treatment (EVT).  Twenty-one, either prospective or retrospective, observational studies describing the recanalization rates and outcomes of BAO treated with EVT were identified.  Additionally, 5 registries on PCI and 1 study protocol of an ongoing prospective RCT near completion were included.  The papers were evaluated and the data was summarized in the article.