Vascular calcification and arterial stiffness in chronic kidney disease: implications and management

Cardiovascular (CV) disease is the commonest cause of mortality in patients with chronic kidney disease (CKD). Vascular calcification (VC), induced by calcium and phosphate excess and uraemia, is a major risk factor and is independently associated with CV events and death. Local and systemic calcium-regulatory proteins as well as inhibitory extracellular factors are involved in the pathogenesis of VC. In CKD the balance becomes dysregulated leading to differentiation of vascular smooth muscle cells into phenotypically distinct osteoblast-like cells with subsequent ossification of the arterial wall. Associated with imbalances in mineral metabolism, VC has intimate interactions with bone mineralization and enhanced bone resorption. Arterial stiffness represents the functional disturbance of VC, with reduced compliance of large arteries, and predominantly results from greater medial calcification. As with VC, arterial stiffness is an independent predictor of CV mortality and patients with CKD have greater arterial stiffness than the general population resulting in the principal consequences of left ventricular hypertrophy and altered coronary perfusion. Both VC and arterial stiffness can be measured through non-invasive techniques involving computed tomography, ultrasound, echocardiography, and pulse wave velocity. Management in CKD is difficult but detection, prevention and treatment is crucial to reduce CV mortality. The optimal control of mineral metabolism, especially hyperphosphatemia with non-calcium based phosphate binders, has been shown to be effective to reduce VC, and attenuation of arterial stiffness, especially with good blood pressure control, can have a favourable effect with regression of left ventricular hypertrophy. The use of bisphosphonates, calcimimetics, vitamin D therapy and newer experimental treatments, as well as nocturnal dialysis, may have potential benefit.