CAC, CIMT, and ABI for CV Risk Prediction

Study Questions:

Does coronary artery calcification (CAC), carotid intima-media thickness (CIMT), and/or ankle-brachial index (ABI) improve cardiovascular (CV) risk discrimination among adults without clinical CV disease (CVD)?

Methods:

Data were from the Heinz Nixdorf Recall study, a population-based study of adults between the ages of 45 and 74 years at entry who resided in the German Ruhr area. Participants who completed CAC, CIMT, and ABI measures and who were free of CVD at baseline were included. The cohort was stratified by Framingham risk score (FRS). The primary outcome of interest was incident major CV events (coronary event, stroke, CV death).

Results:

A total of 3,108 subjects (mean age 59.2 years and 47.1% male) were included. During the 10.3 years ± 2.8 years of follow-up, incident CVD events occurred in 223 participants. All three markers were associated with CV events: for CAC, hazard ratio [HR] = 1.31 (95% confidence interval [CI], 1.23-1.39) per 1-unit increase in log(CAC + 1); for CIMT, HR = 1.27 (95% CI, 1.13-1.43) per 1 standard deviation (SD); and for ABI, HR = 1.30 (95% CI, 1.14-1.49) per 1 SD. All models were adjusted for FRS. CAC led to the highest reclassification in the total cohort. However, both CIMT and ABI demonstrated significant improvement in net-reclassification as well (net-reclassification improvement, CAC: 0.55 [95% CI, 0.42-0.69]; CIMT: 0.32 [95% CI, 0.19-0.45]; and ABI: 0.19 [95% CI, 0.10- 0.28]).

Conclusions:

The authors concluded that CAC provided the best discrimination of risk compared with CIMT and ABI, particularly in the intermediate-risk group, whereas CIMT may be an alternative measure for reassurance in the low-risk group.

Perspective:

The data from this large population-based study suggest the value of CAC for those with an intermediate risk of CVD. Confirmation of these findings is warranted for additional populations.

Keywords: Ankle Brachial Index, Atherosclerosis, Cardiac Imaging Techniques, Carotid Intima-Media Thickness, Coronary Artery Disease, Plaque, Atherosclerotic, Primary Prevention, Risk Factors, Stroke, Vascular Calcification


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