Posterior Circulation Stroke and Vertebrobasilar Insufficiency

Posterior circulation stroke is a unique entity that has multiple significant differences from stroke affecting the anterior circulation. In this chapter, we discuss the anatomical variations that contribute to ischemic posterior circulation stroke and the etiologies that impact the posterior circulation. We further discuss the various causes of vertebrobasilar insufficiency (VBI), which is characterized by insufficient blood flow to those parts of the brain fed by the posterior circulation including the bilateral vertebral arteries (VAs), the basilar artery (BA), and the bilateral posterior cerebral arteries (PCAs). The posterior circulation supplies blood flow to various critical structures, leading to characteristic signs and symptoms. Recognition of the wide range of symptoms and clinical manifestations of posterior fossa stroke and other VBI syndromes is critical because timely, effective management of VBI depends on the underlying etiology. Because atherosclerosis is the underlying etiology for most cases of VBI, medical management with dual antiplatelet therapy is the first-line treatment for symptomatic disease. Endovascular or surgical management is reserved for symptomatic disease not responsive to medical management. Acute VBI results in acute stroke. Although no level I evidence exists for the use of mechanical thrombectomy for acute BA, vertebrobasilar, VA, or PCA occlusion, several prospective registries have shown the effectiveness of this endovascular treatment. In patients who meet the eligibility criteria, intravenous tissue plasminogen activator remains the recommended first-line treatment. However, in our experience, mechanical thrombectomy is highly effective for select cases of acute vertebrobasilar artery occlusion.