Evaluation of vascular calcinosis risk factors in patients on chronic hemodialysis: lack of influence of calcium carbonate.

Linear calcifications of the abdominal aorta and of the iliac and femoral arteries were measured yearly for 3 years on X rays of 24 patients on chronic hemodialysis taking variable amounts of calcium carbonate and Al(OH)3 but no pharmacological doses of vitamin D or 1 alpha-hydroxylated vitamin D derivatives. The speed of their extension appeared exponential and covariant with the male sex, age only for men and, independently of these two factors, with diastolic blood pressure and blood triglycerides. Plasma concentrations of calcium, phosphate and glucose were covariant with the extension of calcinosis only at a borderline level. The doses of calcium carbonate and the levels of plasma alkaline phosphatase were not at all covariant.

CONCLUSIONS

(1) The effect of high doses of calcium carbonate is possibly harmful only when supraphysiological levels of plasma calcium are induced, whereas plasma phosphate is not adequately decreased. The doses of calcium carbonate per se have no deleterious effect (2). Since alkaline phosphatase is not covariant with the extension of calcinosis, the degree of hyperparathyroidism per se does not seem to play a causative role in vascular calcinosis (3). The main risk factors of vascular calcinosis are: age, the male sex, diastolic blood pressure and blood triglycerides.