The role of ankle brachial index and carotid intima-media thickness in vascular risk stratification

Abstract

Purpose of review: To summarize recent findings on the role of ankle brachial index (ABI) and carotid intima-media thickness (cIMT) in vascular risk stratification.

Recent findings: The combination of either ABI or cIMT with the Framingham risk score does not appear to improve risk stratification more than the Framingham risk score alone.

Summary: ABI and cIMT are well studied markers of atherosclerotic burden. Considerable evidence shows that they both are independently associated with increased vascular morbidity and mortality. However, their value in identifying high-risk patients among those with low or intermediate estimated risk appears to be limited. Regarding cIMT, this might be because cIMT is mostly a marker of early atherosclerosis. On the contrary, peripheral arterial disease (i.e. ABI <0.9) develops mostly in patients who already have high estimated vascular risk (e.g. elderly smokers or diabetic patients). Nevertheless, ABI is inexpensive, can be performed quickly and has high validity and good reproducibility, in contrast to the technical equipment and expertise required for measuring cIMT. Accordingly, ABI should be measured in patients at risk for peripheral arterial disease but not in all intermediate-risk patients indiscriminately. Finally, it has not been evaluated whether adding ABI or cIMT to the Framingham risk equation to guide management decisions will prevent more events than the use of the Framingham risk equation alone. Before the wider implementation of ABI or cIMT for risk stratification, this critical question has to be answered.