Rachel Forman, MD
I was happy to see that although the ESO-WSO 2020 annual meeting was postponed, we still had the opportunity to virtually hear the results of some recent large clinical trials. One of the five trials presented was the Basilar Artery International Collaboration Study (BASICS) presented by Dr. Wouter Schonewille from The Netherlands. Posterior circulation occlusions have been largely excluded from the main endovascular randomized control trials, so these results were highly anticipated.
Many of us are familiar with the devastating effects of a basilar artery occlusion (BAO), and from a personal experience, some of these cases have been very challenging without having the guidance of large trials as we do with anterior circulation occlusions. The clinical presentations, stroke severity, and collateral patterns are inherently different. This trial was an international, multicenter, controlled trial with randomized treatment-group assignments investigating the efficacy and safety of endovascular therapy (EVT) plus best medical management (BMM) versus BMM alone <6 hours of estimated time of BAO. Patients were randomly assigned (1:1 ratio) to EVT+BMM or BMM alone and stratified according to: randomizing center, use of IVT, and NIHSS (<20 vs >20). The enrollment period was from 2011 through 2019. Patients were excluded with intracranial hemorrhage, extensive brainstem ischemia, or cerebellar mass effect/acute hydrocephalus. The calculated sample size was 300 patients assuming favorable outcome in 46% with EVT+BMM and 30% with BMM. Primary outcome was mRS <3 at 90 days. Secondary outcome measures included clinical outcomes (mRS 0-2 at 90 days and mRS distribution) and imaging outcomes (posterior circulation ASPECTS score at 24 hours and basilar artery patency at 24 hours).