Defining vascular aging and cardiovascular risk.

Whereas vascular aging has been identified as an emerging cardiovascular risk factor, definitions of 'normal' and 'early' vascular aging (EVA) and their precise relationship with cardiovascular risk are currently equivocal. The present review discusses the concept of vascular aging; that structural and functional changes occur in the large arteries with aging; and EVA; that such age-associated changes are accelerated in individuals at increased cardiovascular risk; and their metrics; indeed, in order to provide a definition of when EVA occurs in clinical practice, reference values of normal and accelerated vascular aging are needed. Due to the complex nature of age-associated changes in the large arteries described above, there are different parameters relating to vascular aging which can be measured. These broadly include aortic and carotid stiffening; aortic and carotid lumen dilation; endothelial dysfunction (usually measured via brachial flow-mediated dilatation); and carotid intima-media thickness.