Treatment of posterior circulation stroke: Acute management and secondary prevention

Abstract

One-fifth of strokes occur in the territory of the posterior circulation, but their management, particularly acute reperfusion therapy and neurointervention procedures for secondary prevention, has received much less attention than similar interventions for the anterior circulation. In this review, we overview the treatment of posterior circulation stroke, including both interventions in the acute setting and secondary prevention. We focus on areas in which the management of posterior circulation stroke differs from that of stroke in general and highlight recent advances.Effectiveness of acute revascularization of posterior circulation strokes remains in large parts unproven. Thrombolysis seems to have similar benefits and lower hemorrhage risks than in the anterior circulation. The recent ATTENTION and BAOCHE trials have demonstrated that thrombectomy benefits strokes with basilar artery occlusion, but its effect on other posterior occlusion sites remains uncertain. Ischemic and hemorrhagic space-occupying cerebellar strokes can benefit from decompressive craniectomy.Secondary prevention of posterior circulation strokes includes aggressive treatment of cerebrovascular risk factors with both drugs and lifestyle interventions and short-term dual anti-platelet therapy. Randomized controlled trial (RCT) data suggest basilar artery stenosis is better treated with medical therapy than stenting, which has a high peri-procedural risk. Limited data from RCTs in stenting for vertebral stenosis suggest that intracranial stenosis is currently best treated with medical therapy alone; the situation for extracranial stenosis is less clear where stenting for symptomatic stenosis is an option, particularly for recurrent symptoms; larger RCTs are required in this area.

Keywords: Vertebral; acute stroke therapy; basilar; posterior circulation; prevention; stenting; treatment; vertebrobasilar.

Figure 1.

Results of the four large randomized controlled trials of endovascular treatment in patients with acute stroke from basilar artery occlusion.^, The odds or risk ratios and 95% confidence intervals are shown for a favorable outcome defined as modified Rankin score of 0–3 at 3 months. BEST: Basilar artery occlusion Endovascular intervention versus Standard medical Treatment; BASICS: BASilar artery International Cooperation Study; ATTENTION: EndovAscular TreaTmENT for acute basilar artery occlusION; BAOCHE: Basilar Artery Occlusion CHinese Endovascular trial; OR: odds ratio; RR: risk ratio.

Figure 2.

87-year-old man with acute BAO, NIHSS = 8, randomized to endovascular treatment in the BASICS trial: (a) extensive hypoperfusion (blue color) on mean transit time on perfusion CT from the medullary (A1) to midbrain (A2) levels. Thrombolysis at 130 min. (b) Conventional angiography showing tight stenosis at right vertebral origin (B1: arrow) and basilar artery occlusion (B1, top of image); thrombectomy with basilar artery recanalization at 4.2 h after onset, complicated by a non-stenosing mid-basilar dissection (B2, arrow). (c) Sub-acute diffusion-weighted MRI showing limited stroke volume in the right cerebellum (C1) and no visible lesion in the midbrain (C2). Favorable outcome at 3 months with minimal disability. Copyright Patrik Michel.

Figure 3.

46-year-old man with multilevel posterior circulation stroke and BAO. NIHSS = 8. (a) Diffusion-weighted MRI showing extensive left inferior (A1) and superior (A2) cerebellar infarcts. Basilar artery recanalization by direct thrombectomy 8 h after last proof of good health. (b) Plain CT 5 h later, showing early cerebellar mass effect. (c) Plain CT after decompressive posterior craniectomy of 5 cm diameter, still showing cerebellar mass effect. (d) Plain CT after second craniectomy on day 3 with enlargement of craniectomy diameter to 7 cm and partial resection (arrows) of left inferior(D1) and superior(D2) cerebellar infarcts. Outcome at 3 months, independent, but not working. Copyright Patrik Michel.

Figure 4.

Frequent sites of atherosclerotic plaques in the posterior circulation. PCA: posterior cerebral artery. Drawing Alexander Salerno.

Figure 5.

Suggested algorithm for prevention of ischemic strokes stratified by the presence of posterior circulation stenosis. Rx: treatment; DSA: digital subtraction angiography; INR: interventional neuroradiologist.

Figure 6.

Recurrence rates for any stroke in a preplanned pooled individual patient data analysis of stenting for symptomatic vertebral artery stenosis: (a) Above, stenting for extracranial stenosis; (b) Below, stenting for intracranial stenosis. Blue: no stenting. Red: with stenting. (reprinted with permission). HR: hazard ratio.