Carotid intima-media thickness as a surrogate marker for cardiovascular disease in intervention studies

BACKGROUND: Cardiovascular trials using clinical endpoints to assess efficacy typically require follow-up of large numbers of participants for 3-5 years. This disadvantage has encouraged the search for well-validated surrogate markers for cardiovascular disease (CVD). These markers may provide earlier indications of efficacy in trials involving fewer participants. One approach gaining interest in recent years is the measurement of atherosclerotic progression, a major underlying cause of CVD. SCOPE: This review article aims to further substantiate the evidence supporting the use of measurement of carotid intima-media thickness (CIMT) as a surrogate marker for atherosclerosis and cardiovascular risk. FINDINGS: CIMT has consistently been related to future CVD events in population studies. CIMT is significantly related with other markers for CVD risk, such as elevated levels of risk factors and presence of atherosclerosis in the coronary arteries. Furthermore, almost all lipid-lowering trials and a large number of blood pressure lowering trials have consistently shown a reduction in progression of CIMT. In addition, the ultrasound technique for measuring CIMT is safe and highly reproducible. CONCLUSION: Thus, CIMT may be used as a surrogate endpoint in clinical trials to enable the benefits of new therapies or regimens to be more rapidly translated into clinical practice.