Posterior circulation ischaemic stroke and transient ischaemic attack: diagnosis, investigation, and secondary prevention.

A fifth of all strokes and transient ischaemic attacks occur in the posterior circulation arterial territory. Diagnosis can be challenging, in part because of substantial overlap in symptoms and signs with ischaemia in the anterior circulation. Improved methods of non-invasive imaging of the vertebrobasilar arterial tree have been used in recent prospective follow-up studies, which have shown a high risk of early recurrent stroke, particularly when there is associated vertebrobasilar stenosis. This finding emphasises the importance of urgent secondary prevention, and the role of stenting for vertebral stenosis is being investigated.