Abstract WMP46: Frequency of High-Risk Features and Stroke Risk in Asymptomatic Carotid Atherosclerosis: Systematic Review and Meta-Analysis

Background: The recommended treatment of asymptomatic carotid atherosclerosis is best medical therapy since the 1% annual risk of stroke is lower than the risk of stroke from revascularization. Specific imaging features may identify patients at increased risk of stroke and optimize the risk-benefit ratio of carotid surgery. To assess the relevance and feasibility of such approach, we aimed to summarize available data on the frequency of high-risk features and the related risk of stroke in patients with asymptomatic carotid atherosclerosis. Methods: A search of Pubmed and Ovid-Embase identified prospective studies reporting findings of carotid plaque imaging and incidence of stroke in patients with asymptomatic carotid atherosclerosis. Prevalence of high-risk features and incidence of ipsilateral ischemic events were pooled using random-effect meta-analysis. Results: Thirty-five studies enrolling 5808 participants with asymptomatic carotid atherosclerosis of various grades were included. The pooled prevalence (95% CI) of high-risk features on plaque imaging was 28.8 (18.8 - 38.7). The prevalence of neovascularization was 53.5% (45.2 - 61.8), echolucency 40.0% (30.8 - 49.6), lipid-rich necrotic core 35.7% (24.1 - 48.1), thin or ruptured fibrous cap 27.5% (14.2 - 43.3), silent brain infarcts 27.0% (15.3 - 40.5), impaired cerebrovascular reserve 25.9% (10.3 - 45.5), intraplaque hemorrhage 19.2% (13.9 - 25.1), microembolic signals 14.4% (8.9 - 20.8), and ulceration 13.5% (1.3 - 34.0). In 15 cohort studies enrolling 4215 participants, the mean duration of follow-up was 3.5 years (2.0 - 4.6). The pooled incidence of ipsilateral ischemic events was 2.7 per 100 person-years (1.6 - 4.0). This incidence was higher in patients with a high-risk feature (4.9%, 2.3 - 8.2) than in those without (0.9%, 0.2 - 1.8) with an odds ratio of 4.6 (2.3 - 9.3). Conclusion: High-risk features on imaging are frequent in asymptomatic carotid atherosclerosis and associated with a fourfold increase in the annual risk of ipsilateral ischemic events. A risk-oriented selection of patients with asymptomatic carotid atherosclerosis prior to randomization in revascularization trials appears relevant and may be a strategy to prevent stroke in asymptomatic carotid atherosclerosis.