Intraoperative PTH Cutoff Definition to Predict Successful Parathyroidectomy in Secondary and Tertiary Hyperparathyroidism

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 234-256-Bone & Calcium Metabolism: Clinical Trials & Case Series
Clinical
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-242
Monique Nakayama Ohe*1, Rodrigo Oliveira Santos1, Ilda Sizue Kunii2, Aluizio Barbosa Carvalho2, Marcio Abrahao2, Onivaldo Cervantes2, Murilo Catafesta Neves2, Marise Lazaretti-Castro3 and Jose Gilberto Vieira4
1EPM-UNIFESP, Sao Paulo, Brazil, 2EPM-UNIFESP, 3UNIFESP, Sao Paulo SP, Brazil, 4Laboratorio Fleury, Sao Paulo, Brazil
Background: Several methods have been proposed in order to improve success rates in surgical treatment of secondary/tertiary hyperparathyroidism. We evaluated intraoperative PTH measurement (IO-PTH) as a tool to optimize surgical results.

Patients/Methods:86 patients were submitted to total parathyroidectomy with intramuscular presternal autotransplantation from 04/2000 to 10/2009 and were followed for 26.5 months in average. Patients were divided in secondary (SHPT) and tertiary hyperparathyroidism (THPT). In the SHPT group, we included patients under dialysis treatment who presented severe hyperparathyroidism with normal or high serum calcium levels. Tertiary hyperparathyroidism group included renal grafted patients with nonsuppressible parathyroid hyperplasia. IO-PTH (Elecsys-PTH-Immunoassay/Roche) was measured at anesthesia induction (IO-PTH 0’) and 20 minutes (IO-PTH 20’) after completion of parathyroidectomy.

Results: Fifty-two were dialysis patients (29 female/23 male), aged 42.9 years on average (range: 14-64 years) and 34 were renal grafted ones (19 female/15 male), aged 43.5 on average (range: 24-63 years). Among dialysis patients considered cured in the follow-up, mean IO-PTH 0’ was 1591.5 pg/mL (range: 318-4659), and mean IO-PTH 20’ was 208.9 pg/mL (range: 29-823) with 86% decrease on average (range: 67.8-93.5) . Among the renal-grafted cured patients, IO-PTH 0’ was 540 pg/mL (range: 120-2515), and IO-PTH 20’ was 65 pg/mL (range: 13-329) with 87.3% decrease on average (range: 72.6-96.4). Overall, 80.2%  (69/86) presented 80% or more IO-PTH decrease 20 minutes after parathyroidectomy and all were cured. In 11/86 patients (12.7%), a lower IO-PTH drop of 70-79% was observed, and 2 of them (18.1%) failed to cure. 6/86 (6.9%) presented IO-PTH decrease less than 70%: 2 were considered cured; in 3 a supernumerary/ectopic parathyroid was found and removed; and in 1 of the 6 patients, surgery finished after 4-gland excision and the patient failure to cure.

Conclusion: IO-PTH 20' decrease of 80% or more compared to IO-PTH 0' from predicts cure in all renal patients throughout follow-up. A decay of less than 70% points to a missed or hyperfunctioning supernumerary gland and is predictive of surgical failure in 66.6%. A marginal IO-PTH drop of 70-79% leaves the decision whether or not the surgery should be continued up to the experienced surgeon.

Nothing to Disclose: MNO, ROS, ISK, ABC, MA, OC, MCN, ML, JGV

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm