Abstract
Backgrounds: Recent studies have reported carotid (CA) lumen dilation as a risk factor for cardiovascular disease. However, the relationship of CA hemodynamic status and elastic properties to CA enlargement has not been investigated systematically in humans. Methods and results: We recorded CA pressure and axial flow velocity waveforms simultaneously using phase-locked echo tracking method and continuous Doppler method in 56 healthy volunteers (age: 20-72 years). Diastolic lumen diameter (DD) of the common carotid artery (CCA) significantly increased with age (DD = 0.024X age+5.29, r=0.439, P=0.0007). DD also significantly correlated with carotid flow volume (CAFV, r=0.754), CA distensibility (r=-0.45), body surface area (BSA, r=0.371), CA pulse pressure (PP, r=0.352), CA systolic blood pressure (SBP, r=0.333), CA augmentation index (r=0.320), brachial(BA) SBP (r=0.289), BA PP (r=0.266). According to multivariate regression analysis, age, CAFV, and BSA were independent determinants of DD (model 1; R2=0.688, p<0.0001). R2 was similar even after excluding age (model 2; R2 =0.686, p<0.0001). Independent determinants were CAFV, BSA, CA SBP, and heart rate (HR). With aging, CA SBP and HR increased significantly, but CAFV and BSA did not change. Conclusions: DD in the CCA was a multi-factorial parameter. Increased CAFV, BSA, CA SBP, and HR were key contributors to CA lumen dilation, but only CA SBP and HR seemed to be associated with age-related changes. Results of the present study should aid the interpretation of findings in large-scale prospective studies. [J Physiol Sci. 2007;57 Suppl:S82]
