OR23-06 Long Term Outcomes Of Parathyroid Autografts In Primary Hyperparathyroidism

Disclosure: E. Chuki: None. A. Graf: None. A. Ninan: None. R. Tora: None. T. Abijo: None. N.M. Center: None. N. Nilubol: None. L.S. Weinstein: None. S.K. Agarwal: None. W.F. Simonds: None. S. Jha: None. Background: Autologous implantation of parathyroid tissue is frequently utilized in patients with heritable forms of primary hyperparathyroidism (PHPT). There is sparse data on long-term functional outcome of these grafts and post-graft recurrence of PHPT. Objective: We aimed to investigate the long-term outcome of parathyroid autografts and assess the frequency of post-graft PHPT recurrence. Methods: Retrospective study of patients with PHPT who underwent parathyroid autografts from 1991 to 2020. Results: We identified 115 patients with PHPT who underwent 135 parathyroid autografts. A significant majority (106 of 115 patients, 92%) had a heritable form of PHPT, with MEN1 being the most common (93 of 115 patients, 81%). Median follow-up duration since graft was 10 [4-20] years. 119 (88%) were to brachioradialis, 11 (8%) to sternocleidomastoid and 5 (4%) to deltoid. There were 86 immediate (64%) and 49 delayed (36%) grafts. Of the 135 grafts, 54 (40%) were fully functional at last follow-up, 13 (10%) partially functional, 44 (32%) non-functional while functional status of 24 (18%) grafts could not be ascertained. Age at graft, thymectomy prior to autograft, graft type (delayed/immediate) or duration of cryopreservation did not predict functional outcome. There were 45 (83%) post-graft recurrences of PHPT among 54 fully functional grafts at a median duration of 8 [4-15] years after grafting. Parathyroidectomy was performed in 42/45 but surgical cure was attained in 18/42 (43%) only. 12 of 18 (67%) recurrences were graft-related while the remaining 6 (33%) had a neck or mediastinal source. Median time to recurrence was 16 [11-25] years in neck or mediastinal source versus 7 [2-13] years in graft-related recurrences. Median PTH gradient was significantly higher at 23 [20-27] in graft-related recurrence versus 1.3 [1.2-2.5] in neck or mediastinal source (P = 0.03). Nineteen patients had multiple parathyroid grafts. Median pre-repeat-graft PTH of 7.5 [6.5-18.5] pg/mL with ionized calcium of 1.15 ± 0.145 (reference:1.09-1.30) mmol/L served as an indicator of the need for a repeat graft. Discussion: Post-graft recurrence occurs frequently within the first decade after grafting. Source of excess PTH in post-graft recurrence of PHPT can be challenging to localize. Time to recurrence after graft is significantly shorter and PTH gradient higher for graft-related recurrence. Presentation: Saturday, June 17, 2023