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 months, all the patients in the (-ve) group responded to calcitriol; while 8 of the 9 patients (89%) in the (+ve) group didn't respond. The difference in response between the 2 groups was statistically significant (p<0.001).


CONCLUSIONS
We conclude that MIBI scan is a reliable technique in predicting the response to treatment with i.v. calcitriol in patients with secondary hyperparathyroidism.
Owda
Ali K
AK
Department of Nephrology, Riyadh Armed Forces Hospital, Saudi Arabia. aaalkhader@hotmail.com
Mousa
Dujana
D
Abdallah
Abdallah H
AH
Hawas
Fahad A
FA
Al-Harbi
Wedad
W
Fedail
Halima
H
At-Shoail
Ghada
G
Al-Sulaiman
Mohamed H
MH
Al-Khader
Abdullah A
AA
D000328:Adult; D002117:Calcitriol / Q000008:administration & dosage* / Q000627:therapeutic use*; D002120:Calcium Channel Agonists / Q000008:administration & dosage* / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000503:physiopathology; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D017256:Technetium Tc 99m Sestamibi; D013997:Time Factors; D016896:Treatment Outcome
D002120:Calcium Channel Agonists; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D002117:Calcitriol