References for this Review were identified through searches of PubMed with the search terms “posterior circulation” AND “stroke” OR “TIA” and “vertebrobasilar” AND “stroke” OR “TIA”, from 1990 until March, 2013. Articles were also identified through searches of the authors' own files. Only papers published in English were reviewed. The final reference list was generated on the basis of originality and relevance to the broad scope of this Review.
ReviewPosterior circulation ischaemic stroke and transient ischaemic attack: diagnosis, investigation, and secondary prevention
Introduction
A fifth of all transient ischaemic attacks (TIAs) and ischaemic strokes are in the territory of the vertebrobasilar (also known as posterior) circulation.1 Despite their importance, ischaemic events in this location have received much less attention than those in the carotid artery territory. Recent studies have shown that they are associated with a high risk of early recurrent stroke (see later) and therefore effective secondary prevention is important. Such an approach needs accurate clinical diagnosis, detection of the underlying cause, including arterial stenosis, and effective medical and surgical or neurointerventional treatments. Posterior circulation ischaemia presents particular challenges in diagnosis, investigation, and treatment, but recent research and ongoing studies are improving our understanding in this area. In this Review, we focus on the diagnosis, investigation, and secondary prevention of posterior circulation ischaemic stroke and TIA and highlight recent insights and advances. We will not cover management of acute stroke or basilar artery thrombosis, which has recently been reviewed.2
Section snippets
Anatomy of posterior circulation
The vertebral artery usually arises as the first branch of the subclavian artery and occasionally directly from the aortic arch (figure 1). It is conventionally divided into four segments.3 The first (V1) is from the origin of the vertebral artery to where it enters the foramen in the transverse process of the fifth or sixth cervical vertebra. The second segment (V2) is the part that courses cranially through the transverse foramina, until the artery emerges beside the lateral mass of the
Disease mechanisms
The most common causes of posterior circulation ischaemia are cardioembolism, large artery atherosclerosis, and small artery disease. Atherosclerosis often occurs at or near the origin of the vertebral artery.
Atherosclerosis can also occur in the distal vertebral and basilar arteries. Extracranial stenosis in the posterior circulation is less strongly associated with coronary artery disease and peripheral vascular disease than stenosis at the carotid bifurcation.11 Intracranial atherosclerosis
Clinical features
Because the vertebral and basilar arteries supply the brainstem, cerebellum, and in most cases also the inferior temporal lobe, occipital lobe, and the thalamus, posterior circulation ischaemia can give rise to a broad range of symptoms. These include not only the classic pointers to ischaemia in the posterior territory such as vertigo, ataxia, visual field defects (including hemianopia), eye movement disorders, bilateral weakness, and a reduction in consciousness, but also non-localising
Investigation
The same principles apply to investigation of posterior cerebral ischaemia as to ischaemic stroke in general, but with some important modifications. MRI is more sensitive than CT to posterior circulation infarcts, particularly in the brainstem.42 These are frequently missed on CT but are usually identified on MRI, particularly if diffusion-weighted imaging is done during the acute phase.43, 44 However, diffusion-weighted imaging can occasionally be negative for clinically definite posterior
Risk of recurrent stroke after posterior circulation stroke and TIA
In contrast to carotid territory events, for which research has been stimulated by the development of carotid endarterectomy and stenting, there has, until recently, been little systematic research into the prognosis of patients with posterior circulation TIA. Nevertheless, there has been a widely held opinion that vertebrobasilar TIAs have a more benign prognosis than carotid events,47, 48 mainly on the basis of findings from early cohort studies.48, 49 Patients with vertebrobasilar events are
Asymptomatic vertebral artery stenosis
The prevalence of asymptomatic vertebral artery stenosis in the general population is unknown. In a hospital-based series of 339 patients with peripheral arterial disease, reported in the 1980s, 7% had either a stenosis or retrograde flow in an extracranial vertebral artery.58 In a more recent hospital-based study59 of 3717 patients with clinically manifest atherosclerotic arterial disease, 7·6% of patients (95% CI 6·8–8·5) had an asymptomatic vertebral artery origin stenosis of at least 50% or
Secondary prevention of posterior circulation ischaemia
Much of the management of a patient with posterior circulation stroke or TIA is similar to that for ischaemic stroke in general, and this Review will only cover specific issues relating to secondary prevention of posterior circulation ischaemia.
Medical treatment and risk factor management is similar for anterior and posterior circulation stroke. Recommended treatment is covered in recent guidelines.60, 61 Clopidogrel alone (or aspirin and dipyridamole) is recommended for long-term secondary
Interventional treatment of vertebral artery disease
For symptomatic carotid stenosis, carotid endarterectomy is beneficial. Owing to the high early risk of recurrent stroke, for maximum effectiveness surgery needs to be done soon after TIA or minor stroke.57 Recent data showing a high risk of recurrent stroke in patients with symptomatic vertebral artery stenosis56 suggest that the atherosclerotic vertebral plaque acts in a similar fashion to the symptomatic carotid plaque, and raises the possibility that surgical or neuroradiological
Future directions
In this Review, we have highlighted several areas in which further research is needed to improve diagnosis of posterior circulation stroke and TIA, and for secondary prevention in patients with these disorders. Early and accurate diagnosis remains a challenge in a substantial minority of cases, and diagnostic and risk prediction instruments have lower sensitivity than for anterior circulation stroke and TIA; better diagnostic aids are therefore needed. Finding factors that differentiate
Search strategy and selection criteria
References (75)
- et al.
Basilar artery occlusion
Lancet Neurol
(2011) - et al.
Cervical-artery dissections: predisposing factors, diagnosis, and outcome
Lancet Neurol
(2009) - et al.
Polymyalgia rheumatica and giant-cell arteritis
Lancet
(2008) - et al.
The cerebral vasculopathy of Fabry disease
J Neurol Sci
(2007) - et al.
Isolated labyrinthine infarction as a harbinger of anterior inferior cerebellar artery territory infarction with normal diffusion-weighted brain MRI
J Neurol Sci
(2009) - et al.
Transient isolated brainstem symptoms preceding posterior circulation stroke: a population-based study
Lancet Neurol
(2013) - et al.
Magnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison
Lancet
(2007) - et al.
Analysis of pooled data from the randomised controlled trials of endarterectomy for symptomatic carotid stenosis
Lancet
(2003) - et al.
Fast assessment of stroke and transient ischaemic attack to prevent early recurrence (FASTER): a randomised controlled pilot trial
Lancet Neurol
(2007) - et al.
Clopidogrel plus aspirin versus aspirin alone for reducing embolisation in patients with acute symptomatic cerebral or carotid artery stenosis (CLAIR study): a randomised, open-label, blinded-endpoint trial
Lancet Neurol
(2010)
Clopidogrel with aspirin in acute minor stroke or transient ischemic attack
N Engl J Med
10-year stroke prevention after successful carotid endarterectomy for asymptomatic stenosis (ACST-1): a multicentre randomised trial
Lancet
Stenting of vertebrobasilar arteries in symptomatic atherosclerotic disease and acute occlusion: case series and review of the literature
J Vasc Surg
The Lausanne Stroke Registry: analysis of 1,000 consecutive patients with first stroke
Stroke
Diagnosis and management of vertebral artery stenosis
Q J Med
Cranial neuroimaging and clinical neuroanatomy. Atlas of MR imaging and computed tomography
Hypoplastic vertebral artery: frequency and associations with ischaemic stroke territory
J Neurol Neurosurg Psychiatry
Incidence of unilateral distal vertebral artery aplasia: evaluation by combining basiparallel anatomic scanning–magnetic resonance imaging (BPAS-MRI) and magnetic resonance angiography
Jpn J Radiol
Arterial territories of the human brain
Front Neurol Neurosci
Blood supply of the posterior cerebral artery by the carotid system on angiograms
J Neurol
Circle of Willis variants: fetal PCA
Stroke Res Treat
Artery of Percheron infarction: imaging patterns and clinical spectrum
AJNR Am J Neuroradiol
Incidence and prognosis of > or = 50% symptomatic vertebral or basilar artery stenosis: prospective population-based study
Brain
Differences in stroke subtypes between black and white patients with stroke: the South London Ethnicity and Stroke Study
Circulation
Epidemiology of intracranial stenosis
J Neuroimaging
Vertebrobasilar disease
N Engl J Med
Microembolic signals in acute posterior circulation cerebral ischemia: sources and consequences
Stroke
Vertebrobasilar stenosis predicts high early recurrent stroke risk in posterior circulation stroke and TIA
Stroke
Cerebrovascular dissections—a review part I: spontaneous dissections
Neurosurgery
Antiplatelets vs anticoagulation for dissection: CADISS nonrandomized arm and meta-analysis
Neurology
A review of subclavian steal syndrome with clinical correlation
Med Sci Monit
Posterior circulation strokes without systemic involvement as the presenting feature of Fabry disease
J Neurol Neurosurg Psychiatry
Mitochondrial encephalopathy, lactic acidosis, and strokelike episodes: basic concepts, clinical phenotype, and therapeutic management of MELAS syndrome
Ann NY Acad Sci
Migraine is associated with an increased risk of deep white matter lesions, subclinical posterior circulation infarcts and brain iron accumulation: the population-based MRI CAMERA study
Cephalalgia
Dolichoectasia—an evolving arterial disease
Nat Rev Neurol
Rotational vertebral artery occlusion in a child with multiple strokes: a case-based update
Childs Nerv Syst
The posterior reversible encephalopathy syndrome: what's certain, what's new?
Pract Neurol
Cited by (151)
Evaluation of CINA® LVO artificial intelligence software for detection of large vessel occlusion in brain CT angiography
2024, European Journal of Radiology OpenPearls for the Emergency Clinician: Posterior Circulation Stroke
2023, Journal of Emergency MedicineTreatment of rotational/positional vertebral artery occlusion due to degenerative changes in the cervical vertebrae: A case report and review of the literature
2023, Journal of Orthopaedic ScienceCitation Excerpt :There are many uncommon causes of posterior circulation ischemia. Rotational or positional vertebral artery (VA) occlusion is categorized as one of the more unusual causes of posterior circulation ischemia [3]. Because the VAs run through the transverse foramen of the cervical spine, head rotation can cause VA compression at several points, including the atlantoaxial junction and middle cervical spine [4].
Feasibility and safety of ADAPT in acute distal posterior cerebral artery occlusions
2023, European Journal of RadiologyUsing drug-coated balloons for symptomatic vertebral artery origin stenosis: A systematic review and meta-Analysis
2023, Journal of Clinical NeuroscienceEditor's Choice – European Society for Vascular Surgery (ESVS) 2023 Clinical Practice Guidelines on the Management of Atherosclerotic Carotid and Vertebral Artery Disease
2023, European Journal of Vascular and Endovascular Surgery