Clinical impact of Intima-Media Thickness measurement

The Intima-Media Thickness (IMT) as measured by ultrasonography of carotid arteries is an acknowledged non-invasive method for assessing the impact of vascular risk factors and the progression of cardiovascular disease. The average of the far wall IMT of the common carotid artery (CIMT) from right and left sides is most frequently used. It correlates well with histology and it is a precursor phenotype of early atherosclerosis. Its increase is associated with vascular risk factors. Systematic reviews have quantified this risk, showing that an increase of 0.1 mm in the CIMT is associated with an increased relative risk of 8% of myocardial infarction and 12% of stroke. The evaluation of this parameter is simple, fast, and inexpensive, when integrated into a routine cervical artery ultrasound examination. However, CIMT also has applications in clinical research as an important study outcome, and then a standard measurement protocol should be applied to avoid information and measurement biases. The main consensus statements, both from Europe and North America, outline the technical conditions for IMT assessment and favor the use of automated edge detection software. The relation between CIMT and vascular risk factors or vascular events has been extensively reported. Nevertheless, the implications of CIMT change observed in repeated measurements are not so thoroughly established in the available follow-up studies. The CIMT is an attractive method of measuring target organ damage. However, it will remain a structural evaluation only, a static photograph that does not capture the complex interplay between vessel inflammation and thrombogenic processes.