Relationship between cardio-ankle vascular index (CAVI) and carotid atherosclerosis in patients with essential hypertension

Aortic stiffness measured by aorta-iliac or carotid-femoral pulse wave velocity (PWV) predicts all-cause and cardiovascular mortality. Elrachial-ankle PWV (baPWV) has been developed as a more convenient assessment of arterial stiffness. However, the problem with clinical use of baPWV is that the index itself is closely dependent on blood pressure. Recently, a new method, termed the cardio-ankle vascular index (CAVI), has been proposed in Japan to overcome the disadvantages associated with measuring PWV. However, its clinical usefulness has not yet been fully clarified. In the present study, we compared the usefulness of CAVI with that of ultrasound for evaluating atherosclerosis in patients with essential hypertension. CAVI was measured in 70 hypertensive patients. The intima-media thickness (IMT), cross-sectional distensibility coefficient (CSDC), stiffness parameter beta, and mean diastolic (V-d) and systolic (V-s) flow velocities were evaluated by carotid ultrasound. The V-d/V-s ratio, an index of peripheral arterial resistance, was also calculated. CAVI was positively correlated with IMT (r=0.360, p=0.0022) and stiffness beta (r=0.270, p=0.0239) and negatively correlated with V-d/V-s (r=-0.471, p < 0.0001) and CSDC (r=-0.315, p=0.0079). Stepwise regression analysis revealed that age (r=0.475, p < 0.0001) and pulse pressure (r=0.492, r < 0.0001) were independent determinants of CAVI. These results suggest that CAVI is a useful clinical marker for evaluating atherosclerosis and arteriolosclerosis in patients with essential hypertension.