Prospective study of parathyroid graft function in patients with renal hyperparathyroidism after total parathyroidectomy and heterotopic autotransplantation by measurement of the intact parathyroid hormone concentrations in both antecubital veins.

OBJECTIVE: Evaluation of the value of gradients for intact parathyroid hormone after total parathyroidectomy and heterotopic autotransplantation for renal hyperparathyroidism. DESIGN: Prospective long-term follow-up study. SETTING: Teaching hospital, Germany. SUBJECTS: A total of 115 patients operated on for renal hyperparathyroidism between 1 August 1987 to 15 August 1997. INTERVENTIONS: 100/115 had total parathyroidectomy with autotransplantation. MAIN OUTCOME MEASURES: Analyses of serum calcium, alkaline phosphatase, and intact parathormone in serum 1, 4, 8, 12, 18 and 24 months postoperatively and annually thereafter. Parathormone gradients were calculated as the ratio of the parathormone concentrations in the antecubital venous blood of the grafted and the non-grafted arm. RESULTS: During follow-up (mean 32 months, range 1 month to 9 years), 111 of the 115 patients had one to 10 re-examinations (mean: 4) and in the patients who had had total parathyroidectomy with autotransplantation a total of 437 gradients could be calculated, 91% of which were < or =20. Postoperative hypocalcaemia caused by calcium deficiency of the skeleton led to an increase in parathormone secretion and gradients. Increasing parathormone gradients during follow-up as a result of excessive parathormone secretion in the grafted-arm indicated graft-dependent recurrence. In 6 of the 9 patients with graft-dependent recurrences the gradients exceeded 20. CONCLUSION: The combined sequential assessment of gradients for intact parathyroid hormone and of serum calcium concentrations permits objective evaluation of parathyroid graft function.