ABSTRACT
Cardiovascular disease currently is the leading cause of morbidity and mortality among patients with chronic kidney disease (CKD). Abnormalities in arterial compliance, increased left ventricular mass, and diastolic dysfunction are some of the recognized cardiovascular complications observed in these patients. This study explored the relationship between various parameters of calcium-phosphorus metabolism including 25-hydroxy vitamin D and cardiovascular structure and function in pediatric patients with CKD. This cross-sectional study was conducted using a cohort of 34 children with CKD who had no history of underlying congenital or structural cardiac disease. Two-dimensional echocardiography was used to measure the left ventricular mass index (LVMI), E/A ratio, E', E/E' ratio, and myocardial performance index (MPI). The augmentation index (AI), derived via radial artery tonometry, was used as an indirect measure of central aortic stiffness. Serum biochemical markers of calcium-phosphorus metabolism were simultaneously measured. Univariate analysis showed that LVMI correlated with 25-hydroxy vitamin D (r = -0.54; p < 0.05), systolic blood pressure (SBP) (r = 0.36; p < 0.05), and AI (r = 0.26; p < 0.05). Serum-intact parathyroid hormone (PTH) levels correlated with the E/E' ratio (r = 0.63; p < 0.05) and E' (r = -0.61; p < 0.05). Multiple regression analysis showed that 25-hydroxy vitamin D and SBP were independent predictors of increased LVMI and that PTH was an independent predictor of diastolic dysfunction. This is the first study investigating pediatric patients with CKD that suggests an etiology of nutritional vitamin D deficiency associated with increased left ventricular mass and diastolic dysfunction. The cardiovascular changes observed are not easily reversible. Hence, early preventive therapy with vitamin D supplementation is advocated.
