LONG-TERM INTRAVENOUS CALCITRIOL IN SECONDARY HYPERPARATHYROIDISM: THE ROLE OF TECHNETIUM-99M-MIBI SCINTIGRAPHY IN PREDICTING THE RESPONSE TO TREATMENT

Background: Despite the effectiveness of intravenous calcitriol in suppressing parathyroid hormone secretion in patients with uremic hyperparathyroidism, 50% of the patients remain refractory to this treatment. There are conflicting reports regarding the factors that can predict the response to treatment. Technetium-99m-MIBI scintigraphy was found to be correlated with functional activity of the parathyroid gland. Methods: We, retrospectively, evaluated 16 chronic hemodialysis patients, who were maintained on i.v. calcitriol for 36 months or longer, and who had MIBI scan either at the start of, or within the first 6 months of starting calcitriol. Nine patients had a positive uptake (+ve group), and 7 patients had a negative uptake (−ve group). All patients had an elevated iPTH (iPTH>300 pg/ml) at the start of treatment. Results: The percentage reduction of iPTH in the (−ve) and the (+ve) groups was 65% versus 45% at 12 months, and 65% versus 10% at 36 months respectively. In long-term follow-up of 36 mont...