Carotid Ultrasound Screening for Coronary Heart Disease: Results Based on a meta-analysis of 18 Studies and 44,861 Subjects

BACKGROUND: Carotid artery ultrasound is a possible screening test for future coronary heart disease (CHD) events to select individuals for preventive treatment. OBJECTIVES: To assess the screening performance of carotid artery intima-media thickness (IMT) and carotid plaque in the identification of individuals with CHD. METHODS: Meta-analysis of case-control and cohort studies, reporting carotid IMT or plaque in individuals with and without CHD. Screening performance (detection rates [DRs] for specified false-positive rates [FPRs]) was assessed from the relative Gaussian distributions of IMT among individuals with and without CHD and from the proportion of affected and unaffected individuals with plaque. RESULTS: Eighteen studies, involving 2920 individuals with CHD (mean age range 46-73 years) and 41,941 without (aged 44-73 years) were included in the meta-analysis. For plaque the DR was 62% for an FPR of 30%; likelihood ratio (2.1 [95% CI 1.6-2.4]). For IMT, the DR was 65% for the same 30% FPR (IMT cut-off >or=0.82 mm); likelihood ratio 2.2 (1.9-2.5). The results were similar in case-control and cohort studies. CONCLUSION: Neither carotid plaque nor IMT has a CHD screening performance that is sufficiently discriminatory between affected and unaffected individuals to be a worthwhile screening test.