The prevalence and prognosis of asymptomatic intracranial atherosclerosis in a community‐based population: Results based on high‐resolution magnetic resonance imaging

Abstract

AbstractBackground and purposeIntracranial atherosclerotic disease (ICAD) is a major cause of ischemic stroke in China, but the prevalence and prognosis of asymptomatic ICAD detected using high‐resolution magnetic resonance imaging (HR‐MRI) is largely unknown. The aim of this study was to investigate the prevalence and prognosis in order to guide neurologists in interpreting ICAD detected on HR‐MRI.MethodsWe included stroke‐free participants from a community‐based prospective cohort (Shunyi study participants) who underwent HR‐MRI between July 2014 and April 2016. The participants were divided into two groups: those with or without ICAD (ICAD+ and ICAD−, respectively). ICAD included intracranial artery stenosis and non‐stenotic plaque. The primary outcome was ischemic stroke. Cox proportional hazard models were used to evaluate the association between ICAD and event outcomes.ResultsA total of 1060 stroke‐free participants evaluated by HR‐MRI were included from the Shunyi study. The median age at HR‐MRI was 56 years and 64.7% were female. The ICAD prevalence was 36.3% (n = 385). The ICAD+ group was older and had more cerebrovascular risk factors. The rates of ischemic stroke in the ICAD− and ICAD+ groups were 1.3% (n = 9) and 5.2% (n = 20), respectively, with a median follow‐up time of 54 months. ICAD was associated with an increased risk of ischemic stroke in the unadjusted and adjusted Cox models, with hazard ratios of 4.12 (95% confidence interval [CI] 1.87–9.05) and 2.50 (95% CI 1.05–5.94), respectively. The greatest risk of an event outcome was observed in participants with ≥70% stenosis or occlusion. The features of high‐risk plaques were also identified.ConclusionsWe found that ICAD detected using HR‐MRI increases the long‐term risk of a first‐ever ischemic stroke in a stroke‐free population, suggesting that the current primary prevention protocol of stroke awaits further optimization.