[Results of systematic subtotal parathyroidectomy with thymectomy for tertiary hyperparathyroidism after renal transplantation - 70 patients]

Near Total Parathyroidectomy is Effective Therapy for Tertiary Hyperparathyroidism

Tertiary hyperparathyroidism (3°HPT) is defined as persistent hyperparathyroidism with hypercalcemia after renal transplantation. Near total parathyroidectomy (NTPTX) is the current standard for surgical intervention. The purpose of this study was to identify outcomes of NTPTX. A retrospective review was conducted of surgeries performed between 1994 and 2013. NTPTX resulted in resolution of 96.9 per cent of patients’ hypercalcemia at a median follow-up of three years (interquartile range [IQR], 1 to 8). However, 3.1 per cent of patients remained hypercalcemic with a mean calcium of 10.5 ± 0.2 mg/dL. A total of 78.4 per cent of patients had parathyroid hormone (PTH) levels below 250 pg/mL at a median follow-up of two years (IQR, 2 to 8). The remaining 21.6 per cent had a median PTH of 535 (IQR, 345 to 857). PTH levels dropped from a median of 745 (IQR, 285.75 to 1594.25) pg/mL to 97 (IQR, 60 to 285) pg/mL one month post-NTPTX ( P < 0.01). The most frequent complication was transient hypocalcemia in 27.1 per cent of patients, but no patients became permanently hypocalcemic. In the 1-month postoperative period, only one patient had a cardiac complication, and there was 0 per cent all-cause mortality. Glomerular filtration rate fell from 57.9 ± 28.3 mL/min pre-NTPTX to 53.2 ± 27.5 mL/min at 1-year post-NTPTX ( P < 0.01). NTPTX effectively treats hypercalcemia in 3°HPT. However, PTH remains elevated (greater than 250) in 21.6 per cent of patients.

Exploring the effect of parathyroidectomy for tertiary hyperparathyroidism after kidney transplantation

Tertiary hyperparathyroidism (tHPT) usually regresses after renal transplantation. Persistent tHPT after successful renal transplantation may require parathyroidectomy (PTX). PTX has been reported to be associated with deterioration of renal function and graft survival. We retrospectively analyzed 794 kidney transplants performed at our center with at least 3 years of follow-up to examine the effect of PTX on the renal function and graft survival. Forty-nine of the 794 renal transplant recipients were diagnosed with hyperparathyroidism (HPT) before transplant. Nineteen of 49 patients had persistent tHPT and underwent PTX after kidney transplants. Patients with HPT and non-HPT had similar 3-year graft survival (88% versus 84%, P = 0.51). PTX was associated with a decreased glomerular filtration rate at 3 years (44.7 +/- 20.0 versus 57.7 +/- 23.7 mL/min, P = 0.04); however, there was no statistical difference in the 3-year graft survival (71% versus 88%, P = 0.06). PTX in renal transplant recipients seems to be a safe and effective therapy for persistent tHPT. PTX may be associated with worsening glomerular filtration rate, but it may not be associated with significantly decreased long-term graft survival.

Surgical Treatment of Tertiary Hyperparathyroidism: The Choice of Procedure Matters!

BACKGROUND

Parathyroid surgery (PTX) in patients with tertiary hyperparathyroidism (tHPT) may endanger the long-term survival of transplanted renal grafts. The mechanism by which graft function deteriorates is unknown. We reviewed our experience in regard to the operative procedures and postoperative outcome.

METHODS

Sixty-nine patients were operated on for tHPT between 1987 and 2006 at our institution. Serum (s) calcium, s-creatinine, and levels of intact parathyroid hormone (PTH) were measured before and after PTX. The Modification of Diet in Renal Disease (MDRD) equation was used to estimate glomerular filtration rate (GFR).

RESULTS

The entire patient group developed a deterioration of kidney graft function after PTX. Nineteen of 69 patients developed a decrease in GFR of more than 20% during the hospital stay, persisting for more than one year after PTX. Ten of them had to restart dialysis during the first year after PTX. Mean preoperative s-creatinine was 4.4 +/- 0.6 mg/dl in these patients. When divided according to the surgical procedure performed, only the subgroup who underwent total parathyroidectomy showed a significant worsening of graft function when compared to subtotal or reoperative PTX.

CONCLUSIONS

PTX is an efficient way to treat tHPT but represents a risk for impairing graft function, especially for patients that already demonstrate poor kidney function at the time of surgery. In the aim to prevent transient hypoparathyroidism, which may provoke reduced graft perfusion, as one possible cause of kidney graft deterioration associated with PTX, one should consider subtotal instead of total parathyroidectomy.