Vertebrobasilar stenosis predicts high early recurrent stroke risk in posterior circulation stroke and TIA.

20% of ischemic stroke is in the posterior circulation, but there is little prospective data on early recurrent stroke risk and whether vertebrobasilar stenosis predicts a high recurrence risk. This natural history data are important as it is technically possible to stent such lesions. Contrast enhanced MRA (CE-MRA) and CT angiography (CTA) now allow noninvasive identification of vertebrobasilar stenosis. 216 consecutive patients presenting with posterior circulation TIA or stroke were recruited and prospectively followed for 90 days. 8 patients with vertebral dissection were excluded. CE-MRA or CTA at presentation and 90-day follow-up was available in 182. Any posterior circulation TIA/stroke in the month before the presenting episode was recorded. Taking the first event (including TIA/stroke in the previous month) as the index case recurrent stroke risk in patients with stenosis was 30.5% versus 8.9% in those without; RR 3.4 (95% CI 1.7 to 7.0), P<0.001). Taking the presenting episode as the index case the risk was 13.8% versus 4.1%; RR 3.4 (95% CI 1.1 to 10.5) P=0.0274. The probability of recurrence was highest soon after the initial event. The presence of vertebro-basilar stenosis identifies a group of patients with posterior circulation stroke who have a high early recurrent stroke risk. Early intervention might reduce recurrent stroke risk. Vertebral stenosis can now be treated by stenting, but determining whether this reduces the early stoke risk requires randomized controlled trials.