Carotid Intima-Media Thickness Predicts Future CV Risk

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Carotid Intima-Media Thickness Predicts Future CV Risk

http://www.medscape.com/viewarticle/551469

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Heartwire 2007. © 2007 Medscape

January 30, 2007 (furt, Germany) - Confirmation that carotid

intima-media thickness (IMT) is a reliable predictor of future risk of

cardiovascular events has come from a new meta-analysis [1]. The

meta-analysis, published online January 22, 2007 in Circulation, found

that carotid IMT is a strong predictor of both stroke and MI.

The authors, led by Dr Matthias Lorenz (Johann Wolfgang

Goethe-University, furt, Germany), explain that as carotid IMT

can be measured relatively simply and noninvasively, it is well-suited

for use in large-scale population studies and it is increasingly being

used for risk stratification in individuals and as an end point in

intervention studies. But an important precondition for this

application of IMT is that it can predict future risk of clinical

vascular events. They note that a number of longitudinal studies have

examined the relationship between IMT and future events, but different

studies have used different measurement methods and studied different

populations. Furthermore, some studies have investigated relatively

small populations, which resulted in large confidence intervals for

the risk estimates. To gain more robust estimates of the predictive

value of increased IMT for clinical cardiovascular end points, they

carried out a meta-analysis of these studies.

They reviewed data from eight studies, with a total of 37 197 subjects

who were followed up for a mean of 5.5 years. Results showed that

after adjustment for age and sex, increased carotid IMT was associated

with increased risk of both MI and stroke.

Relative risk of MI and stroke with increases in carotid IMT

Risk of Relative risk 95% CI

MI per standard deviation IMT difference 1.26 1.21–1.30

MI per 0.10-mm IMT difference 1.15 1.12–1.17

Stroke per standard deviation IMT difference 1.32 1.27–1.38

Stroke per 0.10-mm IMT difference 1.18 1.16–1.21

" With data of 200 000 person-years in eight studies, the results of

this meta-analysis improve the precision of estimating the risk that

is associated with IMT, " the researchers write. " For an absolute

carotid IMT difference of 0.1 mm, the future risk of MI increases by

10% to 15% and the stroke risk increases by 13% to 18%, " they report.

In an interview with heartwire, one of the authors, Dr Hugh Markus (St

's University of London, UK), said this study should increase

confidence in carotid IMT as a measure of future risk of

cardiovascular events. " With the large population included in this

meta-analysis, we can be much more certain exactly how carotid IMT

measurements relate to future risk. If you are going to use a marker

as an end point in clinical trials, you have to have robust data on

how it relates to risk, and now we have such data. "

Markus said this study confirms that carotid IMT is a suitable end

point for studies of potential new antiatherosclerotic drugs, and it

can also be used to predict risk in health screening. " The carotid

artery is simple to visualize with an ultrasound scan, as it is so

close to the skin surface, so that a clear measurement of IMT can be

seen very easily, and this study suggests that thickening of this

artery wall by atherosclerosis is a good indicator of what is going on

in the vasculature generally, " he added.

1. Lorenz MW, Markus HS, Bots ML, et al. Prediction of clinical

cardiovascular events with carotid intima-media thickness a systematic

review and meta-analysis. Circulation 2007; 115:459-467.