Are you really as old as your arteries: predicting biological age using the Cardio-Ankle Vascular Index as a marker of vascular stiffness

Since the 1600s, physicians have been fascinated by the ageing process and have attempted to find biological markers which correlate with chronological age. Vascular stiffness has long been linked with ageing and is increasingly important in cardiovascular assessment. Carotid-femoral pulse wave velocity (cfPWV) is a ‘gold standard’ measure of arterial stiffness, predicting cardiovascular events1 and mortality2 independently of blood pressure (BP). The cardio-ankle vascular index (CAVI), performed using a 4 limb-cuff device including long muscular arterial paths, estimates overall vascular compliance, purportedly also BP-independent3. The relationship between arterial compliance and age differs across international patient samples. The Helius study4 compared arterial stiffness in South Asian, African and Dutch patient samples, finding an increase in PWV in South Asian groups which was not entirely explained by conventional CV risk factors. CAVI in Japanese, Chinese and Korean groups5-7 increases with age, variably associated with risk factors. A recent Czech population study8 suggested reference ranges for CAVI in a Caucasian patient group but only up to the age of 65y. Here, we compare CAVI and PWV against age in a UK Caucasian population, looking at the correlation between these measurements with age, and their interaction with other biological factors. We suggest ‘usual’ values for CAVI in a Caucasian population, as has been done in a large-scale international study of PWV9. We make initial comparisons of the change in CAVI with age between our study and published data from Japanese and Korean patient groups. Background 1 – Brighton and Sussex University Hospital Trust, East Sussex, UK 2 – Brighton and Sussex Medical School, University of Sussex, UK 3 – Guy’s and St Thomas’ Hospital, King’s College and King’s Health Partners Results