Mineral Metabolism and Vascular Damage in Children on Dialysis

Abstract

Cardiovascular disease is increasingly recognized as a life-limiting problem in young patients with chronic kidney disease, but there are few studies in children that describe its determinants. We studied the association of intact parathyroid hormone (iPTH) levels and their management on vascular structure and function in 85 children, ages 5-18 years, who had received dialysis for Ն6 months. Compared to controls, dialysis patients had increased carotid intima-media thickness and pulse-wave velocity. All vascular measures positively correlated with serum phosphorus levels, while carotid intima-media thickness and cardiac calcification score also correlated with iPTH levels. Patients with mean time-integrated iPTH levels less than twice the upper limit of normal (n ϭ 41) had vascular measures that were comparable to age-matched controls, but those with iPTH levels greater than twice the upper limit of normal (n ϭ 44) had greater carotid intima-media thickness, stiffer vessels, and increased cardiac calcification than controls. Patients with increased carotid intima-media thickness had stiffer vessels and a greater prevalence of cardiac calcification. There was a strong dose-dependent correlation between vitamin D and all vascular measures, and calcium intake from phosphate binders weakly correlated with carotid intima-media thickness. In conclusion, both iPTH level and dosage of vitamin D are associated with vascular damage and calcification in children on dialysis.

Pediatric Myocardial Stunning Underscores the Cardiac Toxicity of Conventional Hemodialysis Treatments

“…In addition, as a consequence of residual renal function, some exist closer to their dry weight and are thus very sensitive to fluid shifts during dialysis. Combined with a poorly compliant left ventricle (29) and peripheral conduit vessels (15), UF mediates a reduction in cardiac output and BP. In the face of an attenuated coronary reserve, ischemia prevails when the hemodynamic demand of HD is not met by an adequate increase in myocardial blood flow.…”

“…Children and young adults with uremia have a similar constellation of ischemia-predisposing factors to adults, including increased intima media thickness and pulse wave velocity, vascular calcification, early atherosclerosis, and endothelial dysfunction (14,15), but without significant atheromatous CAD. In our experience, the incidence of HD-induced hemodynamic disturbance is comparable to adults, with a 20 to 30% incidence of intradialytic hypotension associated with a relative blood volume reduction of 20 to 25% (16).…”

Taking the pulse of a sick kidney: Arterial stiffness in glomerulonephritis

“…PWV has recently become a focus of interest in a number of clinical conditions where functional and morphological alterations of the arterial tree are of prognostic relevance. Consistent changes in PWV have been observed in children and adults with end-stage renal disease [3][4][5][6][7], diabetes mellitus [8,9], and vasculitis [10][11][12]. Arterial stiffness has been attributed independent prognostic significance.…”

“…Therefore, the continuous elevation of PWV appeared to be predictive of the renal outcome, whereas laboratory markers such as hypocomplementemia and antistreptolysin titers were not. PWV has been shown to be increased in chronic kidney disease [3][4][5][6][7], and the observation of Yu et al might simply reflect chronic kidney disease without any specificity for the underlying disorder. In addition, persistently elevated blood pressure might have confounded the association.…”

Can dialysis modality influence cardiovascular outcome?

“…Amongst children with CKD, both cardiac [5] and vascular damage and calcification [6] are present from the pre-dialysis CKD stages, and these increase in prevalence and severity on dialysis [6]. Importantly, all paediatric and adult studies conducted to date have shown that CVD progression with deteriorating cardiac function and progressive vascular calcification is associated with a long dialysis vintage [1,3,[6][7][8][9][10][11] on both haemodialysis (HD) and peritoneal dialysis (PD).…”