Evaluation of relationship between cardio-ankle vascular index and 24h ambulatory blood pressure variables

OBJECTIVE: CAVI has been defined as a blood pressure (BP) independent index of arterial stiffness, when considering clinic BP values. Arterial stiffness measured with CAVI has also been shown to be a comprehensive indicator of arteriosclerosis, and it would thus be important to explore its relation with daily life BP patterns. Aim of our study was to assess this aspect in a group of treated essential hypertensive patients. DESIGN AND METHOD: 368 caucasian hypertensive patients aged 17-81, consecutively referred to our outpatients Hypertension Center, underwent a thorough clinical evaluation, 24 h ABPM (AND 2430) and CAVI assessment (VaSera Fukuda Denshi). The relation of CAVI with office BP and with 24 h, day and night ABP mean values and variability was investigated. RESULTS: No relation was found between CAVI and all office BP parameters (p NS).Conversely CAVI in univariate analysis showed a significant relation with ambulatory PP (day R = 0,23 p < 0,01-night R = 0,23 p < 0,01- 24 h R = 0,22 p < 0,01) but not with the corresponding ambulatory DBP; a weak correlation was found between CAVI and ambulatory SBP (p < 0.05). The relation between CAVI and ambulatory PP lost significance (p = NS) after accounting for age, the strongest predictor of CAVI (r = 0,59; p < 0,0001). We also observed a relation between CAVI and daytime or 24 h heart rate (HR) (respectively R = 0.23 and R = 0.22; p < 0.01). These relationships remained significant even after accounting for age although not after correction for beta blocker therapy. Concerning short term BP variability we observed only a weak relation of CAVI with 24 h weighted systolic BP standard deviation (R = 0.12; p < 0.05) which lost significance after correction for age. CONCLUSIONS: These data confirm the independence of CAVI from BP values obtained at the time of measurement and offer new information on its association with ABP parameters, suggesting its independence also from the daily blood pressure profile.This support the suggestion that CAVI could have a role in the evaluation of cardiovascular risk independently, at variance from other arterial stiffness indices, from BP levels