Risk of stroke in relation to degree of asymptomatic carotid stenosis: a population-based cohort study, systematic review, and meta-analysis

Figures

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  Figure 1. Risk of recurrent vascular events by degree of asymptomatic ipsilateral carotid stenosis in 207 patients with asymptomatic carotid stenosis in the Oxford Vascular Study The exact range and cutoff points used to report the stenosis and risk data in trials and previous studies vary, with some defining severe stenosis as 70–99% and some as 80–99%. We therefore analysed both cutoff points in the Oxford Vascular Study. TIA=transient ischaemic attack. HR=hazard ratio.

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  Figure 2. Time trends in pooled estimates of annual ipsilateral stroke rates in medically treated patients with asymptomatic carotid stenosis, stratified by degree of baseline carotid artery stenosis, in a systematic review of studies published after 1980 Data are pooled annual ipsilateral stroke rates and 95% CIs. (A) Stroke rate distal to 50–99% stenosis in all studies (n=56). (B) Stroke rate distal to 50–69% versus 70–99% stenosis in all non-selective cohort studies reporting risk for patients with 50–69% or 70–99% stenosis (n=30). (C) Stroke rate distal to 50–99% stenosis in all non-selective cohort studies reporting risk in both patients with 50–69% stenosis and those with 70–99% stenosis (n=15). (D) Stroke rate distal to 50–69% versus 70–99% stenosis in all non-selective cohort studies reporting risk in both patients with 50–69% stenosis and those with 70–99% stenosis (n=15).

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  Figure 3. Time trends in statin use, current smoking prevalence, and duration of follow-up, and ipsilateral stroke rates stratified by confounding factor Data are pooled annual ipsilateral stroke rates and 95% CIs. Data are from all non-selective cohort studies (n=30) reporting stroke risk for patients with 50–69% or 70–99% stenosis. Time trends for medically treated patients with asymptomatic carotid stenosis are shown on the left.

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  Figure 4. Odds of ipsilateral stroke by degree of stenosis in medically treated patients with asymptomatic carotid stenosis (A) Five cohort studies reporting stroke risk for patients with 0–99% stenosis. (B) Seven cohort studies reporting stroke risk for patients with 50–99% stenosis. (C) The medical treatment group of randomised trials. OR=odds ratio.