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Thickening of the carotid wall. A marker for atherosclerosis in the elderly? Cardiovascular Health Study
D H O'Leary1, J F Polak, R A Kronmal
1Department of Radiology, Tufts-New England Medical Center, Boston, Mass 02111, USA.
Insights
Internal carotid artery intima-media thickness (ICA IMT) better predicts coronary heart disease (CHD) and atherosclerotic disease (ASD) in older adults than common carotid artery IMT (CCA IMT). Combined measurements offer the strongest prediction of existing disease.
Area of Science:
- Cardiovascular Medicine
- Medical Imaging
- Gerontology
Background:
- Investigated relationships between coronary heart disease (CHD), atherosclerotic disease (ASD), atherosclerosis risk factors, and intima-media thickness (IMT).
- Focused on common carotid arteries (CCA) and internal carotid arteries (ICA) in older adults.
- Assessed IMT as a noninvasive indicator of clinically manifest atherosclerotic disease.
Purpose of the Study:
- Determine if noninvasive IMT measurements can indicate clinically manifest atherosclerotic disease.
- Identify whether CCA IMT or ICA IMT is a better correlate of atherosclerotic disease.
- Examine associations between established risk factors and IMT in CCA and ICA.
Main Methods:
- Measured CCA and ICA intima-media thickness (IMT) using duplex ultrasound in 5117 older adults (aged 65+).
- Collected baseline data on histories of CHD, peripheral arterial disease, cerebrovascular disease, and risk factors (cholesterol, smoking, blood pressure, diabetes, age, sex).
- Employed multiple regression, canonical variate analysis, and logistic regression to analyze relationships and predictive capabilities.
Main Results:
- IMT measurements in both CCA and ICA were significantly greater in individuals with CHD and ASD, even after controlling for sex.
- Internal carotid artery (ICA) IMT measurements were consistently higher than common carotid artery (CCA) IMT.
- Established risk factors explained 17-18% of IMT variability in CCA/ICA and 25% in a combined IMT measure.
- ICA IMT demonstrated a stronger ability to predict prevalent CHD and ASD compared to CCA IMT.
Conclusions:
- While CCA IMT is associated with atherosclerosis risk factors and existing CHD/ASD, ICA IMT shows a stronger association.
- Combined CCA and ICA IMT measurements correlate more strongly with existing CHD, ASD, and cerebrovascular disease risk factors than either measure alone.
- ICA IMT serves as a more potent noninvasive indicator of subclinical atherosclerosis in older adults compared to CCA IMT.
Background And Purpose:
We investigated the relationships between prevalent coronary heart disease (CHD), clinically manifest atherosclerotic disease (ASD), and major established risk factors for atherosclerosis and intima-media thickness (IMT) in the common carotid arteries (CCA) and internal carotid arteries (ICA) separately and in combination in older adults. We wished to determine whether a noninvasive measurement can serve as an indicator of clinically manifest atherosclerotic disease and to determine which of the two variables, CCA IMT or ICA IMT, is a better correlate.
Methods:
IMT of the CCA and ICA was measured with duplex ultrasound in 5117 of 5201 individuals enrolled in the Cardiovascular Health Study, a study of the risk factors and the natural history of cardiovascular disease in adults aged 65 years or more. Histories of CHD, peripheral arterial disease, and cerebrovascular disease were obtained during baseline examination. Risk factors included cholesterol levels, cigarette smoking, elevated blood pressure, diabetes, age, and sex. Relationships between risk factors and IMT were studied by multiple regression analysis and canonical variate analysis. Prediction of prevalent CHD and ASD by IMT measurements in CCAs and ICAs were made by logistic regression, adjusting for age and sex.
Results:
IMT measurements of the CCAs and ICAs were greater in persons with CHD and ASD than those without, even after controlling for sex (P < .001). IMT measurements in the ICA were greater than those in the CCA. Risk factors for ASD accounted for 17% and 18% of the variability in IMT in the CCA and ICA, respectively. These same risk factors accounted for 25% of the variability of a composite measurement consisting of the sum of the ICA IMT and CCA IMT. The ability to predict CHD and ASD was greater for ICA IMT (odds ratio [confidence interval]: 1.36 [1.31 to 1.41] and 1.35 [1.25 to 1.44], respectively) than for CCA IMT (1.09 [1.05 to 1.13] and 1.17 [1.09 to 1.25]).
Conclusions:
Whereas CCA IMT is associated with major risk factors for atherosclerosis and existing CHD and ASD in older adults, this association is not as strong as that for ICA IMT. The combination of these measures relates more strongly to existing CHD and ASD and cerebrovascular disease risk factors than either taken alone.