End-stage renal disease (ESRD) is a state of increased arterial stiffness of extensive vessel calcifications, compared with the non-renal population. Both arterial stiffness and arterial calcifications are potent predictors of all-cause and cardiovascular mortality in ESRD patients. Underlying mechanisms for increased stiffness in uremia are not well-defined, but may include: chronic fluid overload, arterial calcifications, microinflammation, increased sympathetic hyperactivity, activation of the renin-angiotensin system, increased lipid oxidation, and abnormalities of the nitric oxide system.