Progression of cardiac valve calcification and decline of renal function in CKD patients

Abstract

No study has evaluated the efficacy of non-calcium-containing phosphate binders in slowing progression of cardiac valve calcification or deterioration of kidney function in patients with chronic kidney disease not on dialysis. This study addressed these issues. Outpatients (n = 170) with stage 3-4 chronic kidney disease and either mitral or aortic valve calcification were evaluated in this single-center, single-arm, prospective observational study. Patients received sevelamer hydrochloride (1,600 mg/day) for 1 year. Cardiac valve calcification progression was assessed by echocardiography, and decline of renal function by estimated glomerular filtration rate. Parathyroid hormone, FGF-23 and C-reactive protein (CRP) serum concentration and urinary phosphorus excretion were assayed. At the end of treatment with sevelamer (12th month), mitral valve calcification had decreased by 79.3% from baseline. At baseline, 69 patients had grade 1, 97 patients grade 2 and 4 patients grade 3 calcification scores; at the end of the study, 60 patients showed grade 1, and no mitral valve calcification was registered in the remaining patients. An aortic valve score of 1 was found in 32%, score of 2 in 58%, score of 3 in 9% and score of 4 in 1% of patients at baseline; at the end of the study, a score of 1 was found in 95% and a score of 2 in 5% of patients. Significant slowing down of renal function decline (p<0.001), reduction of FGF-23 and CRP concentration (p<0.0001) and phosphorus excretion (p<0.0001) were observed. One-year treatment with a non-calcium-containing phosphate binder may hamper the progression of cardiac valve calcification and slow the decline of renal function, as well as reduce serum concentration of FGF-23 and CRP and urinary phosphorus excretion.