FREE PROTEIN-S DEFICIENCY IN HEMODIALYSIS-PATIENTS DUE TO VASCULAR CALCIFICATIONS

Vascular calcifications are frequent in hemodialysis patients, Its inc idence ranges from 25 to 67% depending of different series. Thirty hem odialysis patients were selected from a dialysis population of 150 pat ients. These 30 patients were divided into two groups: group I include d 15 hemodialysis patients with severe secondary hyperparathyroidism a nd severe, roentgenographically visible diffuse vascular calcification s, and group II included 15 other hemodialysis patients with moderate hyperparathyroidism without radiographic evidence of arterial calcific ations. The control group comprised 20 normal volunteers. In all patie nts, measurements of protein C activity, free protein S and intact par athyroid hormone (PTH) were performed. Statistical analysis showed tha t free protein S in the patients of group I had a tendency to be lower than in the patients of group II (p < 0.01) and the control group (p < 0.001). We did not find significant differences in free protein S be tween group II and control group patients nor a significant correlatio n between intact PTH and free protein S in groups I and II. Protein C activity was found to be in the normal range in both groups. Free prot ein S deficiency in patients of group I would suggest a synthesis defe ct by impaired endothelial cells - due to vascular calcifications (?), Free protein S deficiency could increase the risk of thrombotic compl ications in these patients.