Prospective Evaluation of Parathyroid Graft Function after Total Parathyroidectomy and Heterotopic Autotransplantation in Renal Hyperparathyroidism by Bilateral Determination of Intact Parathormone in Cubital Venous Blood

Abstract. The value of gradients for intact parathyroid hormone (PTH) in the assessment of graft function after total parathyroidectomy/autotransplantation for renal hyperparathyroidism was evaluated in a prospective follow-up study. Altogether 99 patients who underwent operation from August 1, 1987 to December 31, 1996 were prospectively investigated and reexamined postoperatively, including analyses of serum calcium, alkaline phosphatase, and intact PTH in the antecubital venous blood of both arms. The postoperative course is known for all patients. Of the 99 patients included in the study, 95 underwent one to nine reexaminations (median three) over follow-up periods of 1 month to 5 years (median 24 months). Reproducible PTH gradients were established during follow-up. Ninety percent of the calculated gradients were ≤ 20. Intermittent postoperative hypocalcemia, due to calcium deficiency of the skeleton in renal osteopathy, led to an increase in PTH secretion and gradients. Increasing gradients > 20 during follow-up make graft-dependent recurrence probable. The presence of a gradient of approximately 1 in bilaterally elevated PTH levels may be an indication of hyperfunctioning parathyroid tissue in the neck or mediastinum. The combined assessment of the course of gradients for intact PTH, hormone levels in both arms, and serum calcium permits an objective evaluation of parathyroid graft function.