Ectopic calcification. The role of parathyroid hormone.

In 42 uraemic patients radiological skeletal survey, biochemistry and bone histology were compared before and at 6-12 months (42 patients), 12-24 months (26 patients) or 24-48 months (12 patients) after parathyroidectomy. The presence of small vessel or non-visceral soft tissue calcification was not related to the age, sex, duration of end-stage renal failure treatment, total serum calcium, magnesium, phosphate, Ca x P product, alkaline phosphatase, ionised calcium, serum aluminium, iPTH, severity of radiological and histological osteitis fibrosa or parathyroid gland weight. Twenty-three patients (55%) had small vessel and 20 (48%) soft tissue calcification before parathyroidectomy. Despite a marked improvement in subperiosteal erosions (37 healed, 5 improved) and healing of osteitis fibrosa histologically, seven patients developed new and six developed increased peripheral arterial calcification while in 10 patients non-visceral soft tissue calcification disappeared and in two decreased. Successful parathyroidectomy improves non-visceral calcification but not arterial calcification despite reduction in Ca x P product and iPTH.