Prevalence of Asymptomatic Carotid Artery Stenosis in the General Population: An Individual Participant Data Meta-Analysis

Abstract

Conclusion: The prevalence of severe asymptomatic internal carotid artery (ICA) stenosis in the general population ranges from 0% to 3.1%. Summary: The authors sought to determine the prevalence of moderate and severe asymptomatic ICA stenosis using information from four population-based cohort studies. They used pooled cohort data to analyze prevalence of moderate and severe asymptomatic ICA stenosis by age and sex. This was an individual participant data meta-analysis of 23,706 participants from four population-based studies: the Malmo Diet and Cancer Study, Tromoso, Carotid Atherosclerosis Progression Study, and the Cardiovascular Health Study. Moderate asymptomatic ICA stenosis was defined as >50% to 69% stenosis. Severe stenosis was defined as >70% stenosis. Moderate asymptomatic ICA stenosis had a prevalence ranging from 0.2% (95% CI, 0.0%-0.4%) in men aged <50 years to 7.5% (95% CI, 5.2%-10.5%) in men aged ≥80 years. In women, prevalence of asymptomatic ICA stenosis ranged from 0% (95% CI, 0%-0.2%) to 5% (95% CI, 3.1%-7.5%). Severe asymptomatic ICA stenosis ranged from 0.1% to 3.1% (95% CI, 0.0%-0.3%) in men aged <50 years and from 1.7% to 5.3% in men aged >80. In women, the prevalence of severe asymptomatic ICA stenosis increases from 0% (95% CI, 0.0%-0.2%) in those aged <50 years to 0.9% (95% CI, 0.3%-2.4%) in those aged <80 years, respectively. Comment: Screening for asymptomatic ICA stenosis has not been endorsed by the US Preventative Health Services Task Force. There are no data here that will lead to a change in their opinion. Up to age 70 years, the prevalence of high-grade asymptomatic carotid stenosis is <2%. No comorbidity increases that prevalence beyond 2%. Given the relatively benign natural history of asymptomatic ICA stenosis, it seems highly unlikely from these data that screening for asymptomatic high-grade ICA stenosis can be clinically effective or cost-effective in any patient subgroup.