According to the Framingham score, seven major independent risk factors for premature CAD have been identified: cigarette smoking, hypercholesterolaemia (total and low-density lipoprotein [LDL] cholesterol), low serum high-density lipoprotein (HDL) cholesterol, diabetes mellitus, hypertension, male gender and advanced age. On the basis of the number of risk factors present, each subject is classified as low-, intermediate- or high-risk for future events. Subjects with two or more risk factors are considered to be high-risk (10-year risk >20%), and are most likely to benefit from preventative measures. Similarly, recent European guidelines1 stated that the following individuals should be prioritised in clinical practice concerning primary preventative measures:

• asymptomatic individuals with ≥5% 10-year risk of CAD death;
• patients with diabetes (type 2 and 1) with microalbuminuria;
• individuals with markedly increased single risk factors; and
• close relatives of subjects with premature atherosclerotic CAD or who are at a particularly high risk.

Evidence exists suggesting that risk factors, although aetiologically important, are not ideal for screening to find those who are at a high risk of coronary events,² as paradigmatically shown in the British Regional Heart Study (BRHS) risk score, in which only 40% of the total events occurred in the high-risk subgroup, while 60% occurred in the rest of the population.³ In patients with suspected CAD, a variety of techniques such as bicycle or treadmill exercise electrocardiogram (ECG) testing, stress echocardiography or radionuclide scintigraphy are routinely used in diagnostic work-up programmes in the clinic, but due to the time required and the relative complexity of these tools they have rarely been used in the general population for screening purposes.¹

In recent years, with the improved understanding of the atherosclerotic process and the availability of multiple new non-invasive tools for arterial wall and plaque imaging, a debate has been initiated as to whether this approach can identify high-risk subjects more effectively than the traditional risk-factor assessment. Moreover, because atherosclerosis begins at a young age and remains clinically silent for decades, the identification of subclinical stages of the disease has become a distinct opportunity for early intervention. Currently, a number of non-invasive approaches are available for plaque imaging: B-mode ultrasonography of carotid (and femoral) arteries, computed tomography (CT) for coronary calcium scoring and CT coronarography and magnetic resonance imaging (MRI). A number of high-quality studies have demonstrated that these tests can predict risk.^3,4

In this article I will focus on B-mode ultrasonography of carotid (and femoral) arteries. I believe that this is a more effective tool for CAD primary prevention in clinical practice than simple risk-factor assessment, and that clinical cardiologists should incorporate this approach with the aim of improving treatment plans for patients in an office-based setting.⁵ The role of coronary calcium score (CCS) in this clinical context will also be briefly discussed. The imaging of atherosclerosis has evolved into a central method in clinical cardiology with a great potential for improving CAD risk prediction.^2–11 The intima-media thickness (IMT) of carotid arteries and coronary artery calcium detection by cardiac CT have been convincingly shown to be independent predictors of incident CAD events. Expert recommendations have endorsed the use of these imaging modalities in a primary prevention setting,9 allowing a step-up progression towards individualised CAD prevention through a more effective use of drugs. Population-based studies have shown a correlation between the severity of atherosclerosis in one arterial territory and the involvement of other arteries. As carotid and femoral arteries, as well as abdominal aorta, are more accessible for non-invasive examinations than coronary or intra-cerebral arteries, the early detection of atherosclerosis in these vessels has become a standard reference for atherosclerosis burden evaluation in the individual.