Abstract 3122: Differences in Intima Media Thickness of the Common and Internal Carotid Arteries
Purpose: Carotid artery intima media thickness (IMT) measurements are recognized as a surrogate marker of atherosclerosis. In risk assessment, it is not clear if IMT measurements should focus on the common carotid artery (CCA) IMT or include the internal carotid artery (ICA) IMT.
Materials and methods: Measurements of the mean CCA IMT and the maximal (max) ICA IMT were made on the members of the Framingham offspring cohort. Traditional risk factors were acquired. Multivariable linear models were used to determine if risk factors differed in their associations with IMT in the carotid artery segments. Multivariable logistic regression model and ROC analysis were used to determine the associations of prevalent cardiovascular disease (CVD) with mean CCA IMT and max ICA IMT.
Results: We studied 3349 individuals (1767 women) with average age of 58.8 ± 9.7 years). We found a significantly stronger association between mean CCA IMT and blood pressure than for max ICA IMT (p < 0.006) as well as for BMI. One standard deviation increase in mean CCA IMT (0.1 mm) was associated with a 25% increase in the odds of prevalent disease while a standard deviation increase in max ICA IMT (0.9 mm) was associated with a 47% increase in the odds of prevalent disease. By ROC analysis, max ICA IMT was a stronger predictor of CVD than mean CCA IMT.
Conclusion: The associations between risk factors in the CCA and ICA segments are different. Mean CCA IMT is more strongly associated to blood pressure than max ICA IMT. Max ICA IMT, equivalent to plaque height, is more strongly associated with prevalent CVD than mean CCA IMT. These differences might affect the utility of IMT in assessing cardiovascular risk.