The role of carotid ultrasound for cardiovascular risk stratification beyond traditional risk factors

Abstract

Primary prevention and early detection of cardiovascular disease is important, as it is the leading cause of death throughout world. Risk stratification algorithms, such as Framingham Risk Score and European Systematic Coronary Risk Evaluation, that utilize a combination of various traditional risk factors have been developed to improve primary prevention. However, the accuracy of these algorithms for screening high risk patients is moderate at best. Accordingly, the use of biomarkers or imaging studies may improve risk stratification. Carotid ultrasound, which measures both carotid intima-media thichkness (cIMT) and carotid plaque, is useful in detecting the degree of subclinical carotid atherosclerosis, and has the advantage of being noninvasive and safe. Several large epidemiologic studies have indicated that cIMT and carotid plaque are closely related with other cardiovascular risk factors and may be useful for risk reclassification in subjects deemed to be at intermediate risk by traditional risk scores. Moreover, recent clinical guidelines for management of hypertension or dyslipidemia highlight the usefulness of cIMT in high risk patients. In this article, we review evidence for the usefulness of measurement of cIMT and carotid plaque for cardiovascular risk stratification.

Keywords: Carotid intima-media thickness; atherosclerosis; cardiovascular diseases; carotid plaque; primary prevention.

Fig. 1

The coronary heart disease incidence rate according to various carotid intima-media thickness (cIMT) categories with and without the presence of plaque. For the overall group (green bar), men (yellow bar), or women (orange bar), the higher cIMT and the presence of plaque is associated with a higher incidence of coronary heart disease (Adapted from Nambi, et al. J Am Coll Cardiol 2010;55:1600-7, with permission from Elsevier).

Fig. 2

Kaplan-Meier estimates of new-onset cardiovascular disease (CVD) according to the presence of plaque. The 8-year rates of cardiovascular disease increase with the presence of internal carotid artery plaque for participants overall (A) and for each Framingham Risk Score category: low risk (0 to <6%) (B), intermediate risk (6 to 20%) (C), and high risk (>20%) (D) (Adapted from Polak, et al. N Engl J Med 2011;365:213-21, with permission from Massachusetts Medical Society).