Abstract
SummaryBackgroundSymptomatic intracranial stenosis was perceived to convey a high risk of recurrent stroke, but two previous trials (SAMMPRIS and VISSIT) did not show superiority of intracranial stenosis stenting over intensive medical management alone. These findings were partly due to a lower than expected risk of recurrent stroke without stenting, possibly reflecting the young age of recruits (median age <60 years), and raise questions about generalisability to routine clinical practice. We therefore studied the age-specific prevalence, predictors, and prognosis of symptomatic intracranial stenosis in a population-based cohort of patients with transient ischaemic attack and minor stroke on intensive medical management.MethodsThe Oxford Vascular Study (OXVASC) is a prospective incidence cohort study of all vascular events in a population of 92 728 people residing in Oxfordshire, UK. All patients, irrespective of age, with transient ischaemic attack and minor ischaemic stroke occurring between March 1, 2011, and March 1, 2018 (follow-up to Sept 28, 2018), were ascertained with multiple methods, including assessment in a dedicated daily emergency clinic and daily review of all hospital admissions. Imaging was by MR angiography of the intracranial and cervicocranial arteries, by CT angiography if MR angiography was contraindicated, and by transcranial Doppler and carotid ultrasound if CT angiography was contraindicated. All patients received intensive medical treatment without stenting, and those with intracranial vascular imaging were analysed in our study, which assessed the age-specific prevalence of 50–99% intracranial stenosis and the associated stroke risk of 50–99% and 70–99% stenosis (adjusted for age and vascular risk factors) during follow-up to Sept 28, 2018.FindingsOf 1368 eligible patients with intracranial vascular imaging, 241 (17·6%) had 385 50–99% symptomatic or asymptomatic intracranial stenosis. The prevalence of symptomatic 50–99% intracranial stenosis increased from 29 (4·9%) of 596 at younger than 70 years to 10 (19·6%) of 51 at 90 years or older (ptrend<0·0001). Of 94 patients with 50–99% symptomatic intracranial stenosis, 14 (14·9%) had recurrent strokes (12 ischaemic and two haemorrhagic) during a median follow-up of 2·8 years (IQR 1·5–4·6). Although symptomatic intracranial stenosis conveyed an increased risk of ischaemic stroke compared with no intracranial stenosis (adjusted hazard ratio 1·43, 95% CI 1·04–1·96), the risk of same-territory ischaemic stroke in patients with 70–99% symptomatic intracranial stenosis tended to be less than those reported in the non-stenting groups of the previous trials (1-year risk 5·6% [95% CI 0·0–13·0] vs 9·4% [3·1–20·7] in VISSIT; 2-year risk 5·6% [0·0–13·0] vs 14·1% [10·1–19·4] in SAMMPRIS).InterpretationThe prevalence of 50–99% symptomatic intracranial stenosis increases steeply with age in predominantly Caucasian patients with transient ischaemic attack and minor ischaemic stroke. However, the risk of recurrent stroke on intensive medical treatment of symptomatic intracranial stenosis is consistent with the two previous randomised controlled trials in younger cohorts, supporting the generalisability of the trial results to routine practice.FundingWellcome Trust, Wolfson Foundation, British Heart Foundation, National Institute for Health Research, National Institute for Health Research Oxford Biomedical Research Centre, Association of British Neurologists.
Highlights
Intracranial atherosclerotic stenosis of the major cere bral arteries is a common cause of ischaemic stroke.[1,2] Intracranial stenosis is prevalent in Asians,[3,4,5,6] but is under-investigated in population-based studies of non-Asians
Patients with intracranial stenosis have long been considered to be at high risk of recurrent stroke, leading to the development and wide use of percutaneous stenting in some countries, two randomised controlled trials did not show provide evidence of benefit for percutaneous stenting over intensive medic al management alone in patients with recently symptomatic intracranial stenosis: Stenting Versus Aggressive Medical Management Therapy for Intracranial Arterial Stenosis (SAMMPRIS)[7] and Vitesse Intracranial Stent Study for Ischemic Stroke Therapy
Multiple imaging methods for screening for intracranial stenosis were used in 21 studies, 15 of which included transcranial Doppler, transcranial Doppler only was used in 11 studies, CT angiography or MR angiography in seven, and catheter angiography in 11
Summary
Intracranial atherosclerotic stenosis of the major cere bral arteries is a common cause of ischaemic stroke.[1,2] Intracranial stenosis is prevalent in Asians,[3,4,5,6] but is under-investigated in population-based studies of non-Asians (appendix pp 1–3). Evidence before this study We did two systematic reviews, one on the prevalence and one on the prognosis of intracranial stenosis in population and hospital-based cohorts of patients with transient ischaemic attack and ischaemic stroke. Intracranial stenosis definition included a 50% reduction of the luminal diameter (usually by the Comparison of Warfarin and Aspirin for Symptomatic Intracranial Arterial Stenosis method) in 28 studies, by transcranial Doppler flow criteria in 11 studies, other percentage reductions in six studies, any reduction in four studies, and was not described in one study. Substantial heterogeneity exists in the reported risk estimates following symptomatic intracranial stenosis (ranging from 4·6% to 45·7%) due to a mixture definitions, case ascertainment, and length of follow-up
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
