CARDIAC-VALVE CALCIFICATION IN HEMODIALYSIS-PATIENTS - ROLE OF CALCIUM-PHOSPHATE METABOLISM

Background. Cardiac valve calcification (VC) has been detected with in creased frequency in haemodialysis (HD) patients, making it necessary to determine the potential pathogenic factors in uraemic patients. Met hods. A total of 92 chronic HD patients (39 female, 53 male) and 92 ag e and gender-matched nondialysis control subjects were evaluated by ec hocardiography and a severity score for VC was determined. Calcium-pho sphate metabolism was evaluated at the beginning of haemodialysis. Res ults. We found a greater prevalence of VC in dialysis patients than in normal patients (mitral annulus 44.5% vs 10%, P=0.02; aortic annulus 52% vs 4.3%, P=0.01). HD patients with mitral calcification were found to be older than patients without calcification, were on long-term re nal replacement therapy, had longer duration of predialysis arterial h ypertension, had greater values of the highest value of mean calcium-p hosphate product in 6 successive months (CaxP) and the highest absolut e value of calcium-phosphate product (CaxP,,,). We also found a positi ve correlation between calcification score, age, and CaxP. No correlat ion was found between actual VC and arterial hypertension or parathyro id hormone. Multiple stepwise regression analysis selected age and Cax P as the most predictive parameters for mitral calcification (r=0.47). Mitral calcification was associated more frequently with rhythm and c ardiac conduction defects, valvular insufficiency and with peripheral vascular calcification. Aortic calcification was correlated with age ( r=0.42) and longer duration of predialysis arterial hypertension. Conc lusion. Our study confirmed an increased prevalence of VC in HD patien ts and selected age and calcium-phosphate product as the most predicti ve parameters. These findings support careful monitoring of calcium me tabolism beginning at the early stages of end-stage renal failure to r educe the risk of heart disease.