Carotid intima-media thickness (CIMT) is a valuable non-invasive measure used to assess subclinical atherosclerosis and predict cardiovascular risk. The interpretation of CIMT results requires understanding the reference values and their association with cardiovascular risk factors. According to the European Heart Journal, reference intervals for CIMT have been established using data from a healthy population, allowing for age- and sex-specific percentiles to be used in clinical practice.[1] These reference values facilitate the comparison of observed CIMT values with predicted normal values, aiding in the identification of individuals at increased cardiovascular risk.
Technical aspects significantly impact the measurement and interpretation of CIMT. The European Journal of Preventive Cardiology highlights that device characteristics, sonographer variability, and ultrasound protocols can influence CIMT measurements.[2] Standardization of these factors is crucial for accurate assessment. The American Society of Echocardiography and the Society of Vascular Medicine and Biology recommend using the mean common carotid artery (CCA) CIMT and the maximum internal carotid artery (ICA) CIMT for risk stratification.[3] These measurements are associated with cardiovascular events, with the presence of carotid plaque providing additional prognostic value.
CIMT values are predictive of future cardiovascular events. A meta-analysis published in Circulation found that a 0.1 mm increase in CIMT is associated with a 15% increase in the risk of myocardial infarction and a 17% increase in the risk of stroke.[4] The New England Journal of Medicine reported that the maximum ICA CIMT significantly improves cardiovascular risk classification when added to traditional risk factors.[5] This underscores the importance of incorporating CIMT measurements into comprehensive cardiovascular risk assessments.
The clinical utility of CIMT is further supported by its role in monitoring the progression of atherosclerosis. A meta-analysis in Circulation demonstrated that interventions reducing CIMT progression are associated with a decreased risk of cardiovascular events.[6] This finding supports the use of CIMT as a surrogate marker in clinical trials evaluating cardiovascular risk reduction strategies.
In summary, interpreting CIMT results involves comparing measured values to established reference intervals, considering technical factors that affect measurement accuracy, and understanding the predictive value of CIMT for cardiovascular events. The inclusion of CIMT in risk assessment models enhances the identification of individuals at high risk for cardiovascular disease, and monitoring CIMT progression can guide the effectiveness of therapeutic interventions.
