Stroke Risk of Asymptomatic Intra- and Extracranial Large-Artery Disease in Apparently Healthy Adults

Abstract

Background: The predictive value of asymptomatic intracranial artery stenosis for future stroke remains uncertain. The aim of this study is to assess the stroke risk of asymptomatic intracranial artery stenosis and to compare it with that of extracranial artery disease. Methods: The study subjects were 2,924 participants (mean age 55 years) without any history of stroke. We examined the relation between intra- or extracranial large-artery disease and subsequent cerebrovascular events (mean follow-up 63 months). Results: The incidence rate of total cerebrovascular events in persons with intracranial artery stenosis was 1.3% per year. In the group without plaque in the extracranial carotid arteries, the annual rate of total cerebrovascular events was only 0.6%, but in the group with plaque, the rate was 3.6%. Kaplan-Meier analysis of total events showed a significant difference between the 2 groups (p = 0.002). Conclusions: The stroke risk in subjects with asymptomatic extracranial artery disease is markedly increased if intracranial artery stenosis is also present.