Valvular calcification in hemodialysis patients randomized to calcium-based phosphorus binders or sevelamer.

BACKGROUND AND AIM OF THE STUDY: Valvular calcification is common in patients with end-stage renal disease, and is associated with an unfavorable prognosis. It was hypothesized that sevelamer, a non-calcium-based phosphorus binder, might attenuate the progression of valvular calcification.

METHODS: Two hundred subjects on maintenance hemodialysis received either sevelamer or calcium-based phosphorus binders. To assess the extent of calcification, 186 subjects underwent baseline electron beam tomography (EBT) of the coronary arteries, aorta and mitral and aortic valves, and 132 had follow up EBT scans at week 52. Changes in valvular calcification and combined valvular/vascular calcification were monitored and compared.

RESULTS: At baseline, mitral valve calcification was seen in 46% of subjects, aortic valve calcification in 33%. Most subjects with zero values at baseline failed to progress over one year. Aortic valve calcification was significantly increased in calcium-treated subjects. Changes in mitral valve calcification, and combined mitral + aortic valve calcification were less in sevelamer-treated than in calcium-treated subjects, but not significantly so. When combining valvular and vascular calcification, the median (10%, 90%) change in sevelamer-treated subjects was significantly lower than in calcium-treated subjects (6, -5084 to 1180 versus 81, -1150 to 2944, p = 0.04). The effect of sevelamer remained significant after adjustment for baseline calcification and the time-averaged calcium-phosphorus product, and was independent of the calcium preparation (acetate versus carbonate), geographic region (US versus Europe), LDL- or HDL-cholesterol, C-reactive protein and statin use. Significantly more sevelamer-treated subjects experienced an arrest (45 versus 28%, p = 0.047) or regression (26 versus 10%, p = 0.02) in total valvular and vascular calcification.

CONCLUSION: Sevelamer arrested the progression of valvular and vascular calcification in almost 50% of hemodialysis subjects. Sevelamer treatment, plus intensive control of calcium and phosphorus levels, may attenuate progression of, or achieve regression in, cardiac valvular calcification.