Research in context
Evidence before the study
We searched PubMed with no language restrictions for papers published from Jan 1, 2010, to June 30, 2019, using the search terms “endovascular therapy”, “intra-arterial treatment”, or “mechanical thrombectomy” crossed with “basilar artery occlusion” or “vertebrobasilar artery occlusion”, and “randomized controlled trial”. We identified only one previous randomised trial for vertebrobasilar occlusion. However, this trial used an obsolete treatment method (urokinase infusion) and ended prematurely because of poor recruitment, with only 16 participants. A few non-randomised prospective studies of intra-arterial treatment for vertebrobasilar occlusion have been reported. Although some of these studies have included controls, they had many methodological limitations and were unable to provide any definite evidence regarding the specific benefit of endovascular therapy for patients with acute vertebrobasilar occlusions. We did not find any randomised controlled trials of modern thrombectomy devices for the treatment of acute vertebrobasilar occlusion.
Added value of this study
To our knowledge, our study is the first randomised controlled trial to assess the effect of contemporary endovascular therapy, including stent-retriever-based mechanical thrombectomy, in the treatment of acute vertebrobasilar occlusion. The early termination of the study due to drop in valid recruitment and high crossover rate is consistent with the expected loss of equipoise in face of the several trials showing an overwhelming benefit of thrombectomy in anterior circulation strokes, as well as the known poor outcomes of patients with untreated vertebrobasilar occlusions with severe presentation. Despite not meeting its prespecified primary endpoint on intention-to-treat analysis, the secondary prespecified per-protocol and as-treated analyses of our trial provided some evidence to show that patients undergoing endovascular therapy might have better outcomes than those managed with standard medical treatment alone.
Implications of all the available evidence
The overall evidence points to a benefit of endovascular reperfusion of large vessel occlusion strokes. Our data confirm the poor outcomes of untreated patients presenting with acute vertebrobasilar occlusion and severe clinical findings, and support the overall safety and potential efficacy of early endovascular treatment in this patient population. As seen in our trial, equipoise in this context has been lost in most clinical settings where mechanical thrombectomy can be safely done.