Changes in calcium homoeostasis in patients undergoing liver transplantation: effects of a single infusion of pamidronate administered pre-operatively

Bone turnover, bone loss and fracture risk increase after liver transplanta tion. it has been postulated that peri-operative administration of a bispho sphonate might prevent bone loss and reduce fracture rate. We studied the e ffects of a single pre-operative dose of pamidronate on biochemical paramet ers of skeletal metabolism in the first month after liver transplantation. In a randomized, single-blind study, six of 12 patients with chronic liver disease received 60 mg of pamidronate intravenously on a single occasion 1- 30 days before transplantation. Six other patients undergoing transplantati on received no pamidronate. We measured serum calcium, phosphate, albumin, bone-specific alkaline phosphatase, plasma parathyroid hormone and tartrate -resistant acid phosphatase before pamidronate infusion and at frequent int ervals during the first 30 post-operative days. In treated patients, plasma parathyroid hormone increased 12-fold over baseline values and remained el evated in comparison with baseline at days 26-30; serum calcium and phospha te fell significantly, returning to normal at around day 14 postoperatively . There were no significant changes in any parameter in the untreated group . No changes in bone formation or resorption markers were observed in eithe r group. The large increase in plasma parathyroid hormone concentrations in the treated group is probably secondary to the fall in serum calcium. The magnitude of the increase is much greater than that seen after pamidronate infusion in other patient groups. The lack of change in, or correlation of, serum calcium and plasma parathyroid hormone in the untreated group sugges ts that additional factors release calcium from bone after liver transplant ation, presumably by increasing bone resorption.