Arterial media calcification in end-stage renal disease: impact on all-cause and cardiovascular mortality

BACKGROUND: Cross-sectional and follow-up studies on end-stage renal disease patients showed that arterial calcifications are associated with cardiovascular (CV) morbidity and are an independent predictor of all-cause and CV mortality. However, these studies did not examine the impact on prognosis according to the type of calcification, i.e. intimal vs medial. Arterial media calcification (AMC), a non-occlusive condition, affects haemodynamics differently from arterial intima calcification (AIC), which occurs in atherosclerotic plaques. The aim of this study was to investigate the prognostic value of AMC in relationship to all-cause or CV mortality for stable haemodialysis (HD) patients. METHODS: We included 202 such patients in the present study. At baseline, soft-tissue native radiograms of the pelvis and the thigh were analysed for the presence and type (AMC vs AIC) of arterial calcifications. All patients underwent B-mode ultrasonography of the common carotid artery to determine the presence of atherosclerotic calcified plaques, measurement of aortic pulse wave velocity and echocardiography. RESULTS: AIC was usually observed in older patients with a clinical history of atherosclerosis before starting HD treatment and typical risk factors associated with atherosclerotic disease. AMC was observed in young and middle-aged patients without conventional atherosclerotic risk factors. AMC was closely associated with the duration of HD and calcium-phosphate disorders, including the oral dose of elemental calcium prescribed as phosphate binder (CaCO(3)). Compared to patients with AIC, patients with AMC had a longer survival, but in turn their survival was significantly shorter than that of patients without calcifications. CONCLUSIONS: AMC is a strong prognostic marker of all-cause and CV mortality in HD patients, independently of classical atherogenic factors. The principal effect of AMC on arterial function is increased arterial stiffness.