Carotid Intima-Media Thickness as a Cardiovascular Risk Factor and Imaging Pathway of Atherosclerosis.

Assessment of carotid intima-media thickness (IMT) has emerged as a simple and noninvasive technique for measuring atherosclerotic burden. Although serum biomarkers have been linked to the risk of developing atherosclerosis, carotid IMT has the theoretical advantage of directly visualizing a final consequence of the disease itself, namely atherosclerosis in the vessel wall. The current widespread application of carotid IMT measurements has been based on the validity, standardization, and reproducibility of the measurement and the evidence that an increased carotid IMT can be regarded as an attractive biomarker of atherosclerosis and of increased cardiovascular risk, potentially useful as a therapeutic target in those at increased cardiovascular risk. The utilization of carotid IMT measurements as a surrogate end point in clinical trials evaluating a specific drug intervention may result in considerably smaller efforts and costs than when using a hard end point such as myocardial infarction, stroke, or death. In addition, the use of carotid IMT measurement as a screening tool in clinical practice in association with traditional risk factors may improve risk classification and decisions regarding therapeutic interventions. However, although carotid IMT may be correlated with clinical outcomes, changes in surrogate end points over time that result from a particular therapy may not necessarily be predictive of future cardiovascular events. Therefore, it is necessary to perform more clinical studies to clearly define the relationship between the modifications in carotid IMT and the changes in cardiovascular events. In an era of economic burden, when there is a clear combination of limited resources with high expense of innovation in drug development, carotid IMT represents a reasonable, worthwhile surrogate trial end point with a history of nearly 30 years of technical progress and clinical research. Current data strongly suggest that carotid IMT will continue to successfully be used as a valuable tool in clinical atherosclerosis research.