Graft-dependent Renal Hyperparathyroidism Despite Successful Kidney Transplantation

Disputable Issues of Etiology and Pathogenesis of Tertiary Hyperparathyroidism

Hyperparathyroidism is a clinical and laboratory syndrome characterized by high production of the chief cells of the parathyroid hormone, a calcium-phosphorus metabolism disorder and the organ failure (kidneys, bone tissue).There are primary, secondary and tertiary hyperparathyroidism.This literature review is focused on tertiary hyperparathyroidism and includes the following sections: definition of different forms of hyperparathyroidism, the role of vitamin D in the tertiary hyperparathyroidism development, the development of tertiary hyperparathyroidism in chronic kidney disease patients, the development of tertiary hyperparathyroidism in patients after kidney transplantation, differential diagnosis various forms of hyperparathyroidism, indications for surgical tertiary hyperparathyroidism treatment in patients with kidney disease, in patients with normal kidney function.Objective. The objective of this literature review is to study the current information about this definition, pathogenesis, diagnosis and treatment of tertiary hyperparathyroidism.Methodology. The literature review was taken in English data bases MEDLINE (Pubmed), Scopus, Cochlear library, using following keywords: “secondary hyperparathyroidism pathogenesis diagnosis treatment”, “tertiary hyperparathyroidism pathogenesis diagnosis treatment”, “development of tertiary hyperparathyroidism from secondary hyperparathyroidism”, “chronic vitamin D deficiency, hyperparathyroidism”, “early stages of chronic renal failure, hyperparathyroidism”. Also, search for the same keywords was completed in Russian data base Elibrary.Discussion. Both the lack of a common understanding of this problem, and the presence of diverse and contradictory data of the etiology and pathogenesis indicate the need for further study of tertiary hyperparathyroidism.

Systematic review of surgical and medical treatment for tertiary hyperparathyroidism

BACKGROUND

A significant proportion of patients with chronic kidney disease and secondary hyperparathyroidism (HPT) remain hyperparathyroid after kidney transplantation, a state known as tertiary HPT. Without treatment, tertiary HPT can lead to diminished kidney allograft and patient survival. Parathyroidectomy was commonly performed to treat tertiary HPT until the introduction of the calcimimetic drug, cinacalcet. It is not known whether surgery or medical treatment is superior for tertiary HPT.

METHODS

A systematic review was performed and medical literature databases were searched for studies on the treatment of tertiary HPT that were published after the approval of cinacalcet.

RESULTS

A total of 1669 articles were identified, of which 47 were included in the review. Following subtotal and total parathyroidectomy, initial cure rates were 98·7 and 100 per cent respectively, but in 7·6 and 4 per cent of patients tertiary HPT recurred. After treatment with cinacalcet, 80·8 per cent of the patients achieved normocalcaemia. Owing to side-effects, 6·4 per cent of patients discontinued cinacalcet treatment. The literature regarding graft function and survival is limited; however, renal graft survival after surgical treatment appears comparable to that obtained with cinacalcet therapy.

CONCLUSION

Side-effects and complications of both treatment modalities were mild and occurred in a minority of patients. Surgical treatment for tertiary HPT has higher cure rates than medical therapy.

Results of cryopreserved parathyroid autografts: a retrospective multicenter study

BACKGROUND

The functionality of cryopreserved parathyroid autotransplantation (CPAT) has been evaluated in few studies, mostly conducted by experienced single-institution centers that have reported different success rates ranging from 17% to 83%. In France, CPAT are rare and their functionality has never been evaluated. Moreover, French tissue banks are facing an accumulation of ungrafted samples. The aim of our work was to evaluate the implantation rate of cryopreserved parathyroid samples and the functionality of CPAT in a multicenter study.

METHODS

Data from 9 French tissue banks were analyzed. CPAT functionality was defined as fully functional (normal parathyroid hormone [PTH] and calcium levels without treatment), partially functional (normal PTH levels but need for treatment to maintain normocalcemia), and nonfunctional (low PTH levels and need for treatment). For dialyzed patients, CPAT was considered nonfunctional if the PTH level in the nongrafted arm was less than 20 pg/mL, partially functional if the PTH level was between 20 and 50 pg/mL, and fully functional if the PTH level was between 50 and 300 pg/mL.

RESULTS

The 9 centers had cryopreserved 1376 samples of parathyroid tissue and only 22 (1.6%) had been autografted in 20 patients (65% renal hyperparathyroidism, 20% multiple endocrine neoplasia type 1, 15% "other") by 12 different surgical teams. The median duration of storage was 11.1 months (range, 0.4-28.5). Only 2 autografts (10%) were fully functional, 2 (10%) were partially functional, and 17 (80%) were nonfunctional at 26 months median follow-up.

CONCLUSION

The reimplantation rate is low, and the functionality of CPAT is less than those published by experienced centers. Logistical and technical problems occurring in less experienced centers are probably the main reasons for nonfunctioning implants. Considering the results of this study, we suggest that cryopreservation of parathyroid glands should be abandoned when not performed in very large experimented centers, that CPAT should be used only for patients with hyperplasic parathyroid tissue, and that tissue samples should be systematically destroyed when patients do not have hypoparathyroidism or after 1 year of storage.