Coronary heart disease (CHD) is the leading cause of death in the United States, so primary prevention of cardiovascular events is a healthcare priority. A key challenge to primary prevention efforts is identifying individuals who would be candidates for more intensive medical interventions. A sensitive, technically straightforward, and noninvasive marker of cardiovascular risk that is used in our office setting is a valuable clinical tool.
Measurement of carotid intima–media thickness (CIMT) with B mode ultrasound is a noninvasive and highly reproducible technique for quantifying atherosclerotic burden. Stroke is the third leading cause of mortality in the United States and a leading cause of disability. The carotid arteries provide a window to the coronary arteries. The risk factors for coronary artery disease all the same as for cerebrovascular disease and we have known for at least 2 decades that patients with a major carotid stenosis are very likely to have a major coronary stenosis. There is a direct relationship between the degree of atherosclerosis in the carotid arteries and the coronary arteries. The relationship between the artherosclerotic burden in a carotid artery and a coronary artery is the same as between any to coronary arteries. Thus, carotid atherosclerosis provides a window to the degree of coronary atherosclerosis in an individual. This is not detected using a standard carotid duplex ultrasound examination because by the time a patient has occlusive disease either in coronary or carotid arteries there is extensive atherosclerosis burden.
We examine the carotid artery wall rather than the lumen and thus our carotid ultrasound identifies an earlier stage of atherosclerosis. The combined thickness of the intimal and medial layers is what is identified, measured and used to predict risk. Using a high resolution B-scan ultrasound transducer, 3 segments of the carotid arteries; ie, common carotid, carotid bulb, and internal carotid arteries are examined. We not only look for the presence of nonocclusive plaques but specifically measure See IMT which is an independent predictor of future cardiovascular events including heart attacks, cardiac death and stroke. Performing CIMT measurements clinically is completely noninvasive, does not involve radiation and has no known adverse biological effects.