Association of atherosclerotic risk factors with carotid adventitial thickness assessed by ultrasonography.

PURPOSE: There is increasing evidence that adventitial inflammation may participate in atherosclerosis development. The aim of this study was to investigate which atherosclerotic risk factors correlated with carotid adventitial thickness (AT) and to compare them with those associated with carotid intima-media thickness (IMT). We also set out to test the hypothesis that there is a significant correlation between IMT and AT in the carotid arteries.

METHODS

The far carotid artery wall IMT and AT were measured by high-resolution B-mode ultrasound in 128 persons (mean, 65 +/- 8 years). A number of conventional and novel, clinically and laboratory-derived risk factors were assessed.

RESULTS

Significant correlation (r = 0.35, p < 0.0001) was demonstrated between the IMT and AT. The stepwise forward multiple regression analysis revealed correlations between IMT and leukocyte count, C-reactive protein level, and hypertension, whereas the Chlamydia (C.) pneumoniae IgA antibodies and fibrinogen levels, gender, and smoking correlated merely with AT. The homocysteine/methionine ratio correlated with both IMT and AT.

CONCLUSION

The association between IMT and AT may reflect an interaction between intimal, medial, and adventitial pathology. Different risk factors are associated with the increased AT or IMT. It is possible that inflammation and some chronic infections, such as those induced by C. pneumoniae, could have a marked influence on adventitial cell proliferation.