Carotid intima-media thickness for the practicing lipidologist

It is well known that cardiovascular disease is the number one killer of men and women in the United States and in many parts of the developed world. However, early detection of atherosclerosis remains a challenging area of research and development. Stress echo and myocardial perfusion studies were not designed to be screening tests and the majority of literature using these tests is in populations with a high probability of disease. It must be emphasized that negative stress echo and stress MPI tests only imply a lack of flow limiting disease; they do not indicate lack of atherosclerotic disease. It is important to remember that when these tests are "negative," the implication is favorable short-term prognosis rather than any implication regarding lack of disease. In contrast, carotid intima-media thickness (CIMT) scanning protocols can detect atherosclerotic disease in early and asymptomatic stages. For a number of reasons reviewed in this article, CIMT may be a more optimal screening and risk-stratifying technology: CIMT directly visualizes vasculature unlike biomarkers such as LDL cholesterol, hsCRP, or PLA2.

We performed medline searches for original articles and reviews of carotid IMT from 1985 to the present. We particularly emphasized large multi-center epidemiologic studies of the natural history of patients with carotid IMT measurements.

There is substantial evidence that CIMT is a suitable surrogate for the coronary tree. CIMT is also (along with coronary calcium scoring) recognized by the American Heart Association as a surrogate marker for coronary artery disease. A recent commentary by Stein, et al reviewed the comparison of CIMT to coronary calcium scoring, with favorable findings for CIMT especially in the healthy young and middle-aged populations, as well as women and African American individuals where coronary calcification has more limited utility. Recent findings of the Multi-Ethnic Study of Atherosclerosis indicate further that increased CIMT predicted CVD events in individuals without coronary calcification.