Medical and Surgical Treatment for Secondary and Tertiary Hyperparathyroidism

Effect of High Dose Active Vitamin D Therapy on the Development of Hypocalcemia After Subtotal Parathyroidectomy in Patients on Chronic Dialysis

Background

The period after parathyroidectomy (PTx) in dialysis patients is characterized by periods of severe hypocalcemia. This study aims to investigate the effect of high doses of active vitamin D immediately after PTx on the development of hypocalcemia.

Materials and Methods

We retrospectively reviewed 111 patients with secondary hyperparathyroidism receiving subtotal PTx between 2010 and 2019. A high dose group “HDG” (n = 67) receiving 12 µg alfacalcidol in combination with 8.550 mg calcium acetate per day, which was then adapted according to lab values, was compared with a low dose group “LDG” (n = 44) receiving up to 4 µg alfacalcidol per day. The laboratory values were recorded up to ten weeks postoperatively.

Results

The assumed drops in parathyroid hormone (PTH) and calcium were observed in both groups after PTx. We observed significantly lower calcium values in the LDG between days 4 and 18 postoperatively than in the HDG (p < 0.001). The proportion of severe hypocalcemia after PTx (total calcium <1.5 mmol/l) in the HDG was 8.5% on day 1 and 47% on day 4 in the LDG. Intravenous calcium requirements were significantly lower in the HDG (7.6%) than in the LDG (45.7%; p = 0.001).

Conclusion

The period after PTx in dialysis patients is characterized by an expected drop in PTH and calcium within the first days. Ongoing high turnover is observed in the 2nd and 3rd week after PTx. Administering high doses of alfacalcidol combined with calcium acetate diminishes the episodes of severe hypocalcemia and the need for intravenous calcium.

Hiperparatiroidismo primario: conceptos para el cirujano general

Durante las últimas décadas, la incidencia del hiperparatiroidismo primario ha venido en aumento, muy probablemente relacionado con la mayor accesibilidad a los estudios diagnósticos; sin embargo, la forma más común de presentación clínica del hiperparatiroidismo primario es asintomática, en más del 80% de los pacientes. En la actualidad, es menos frecuente el diagnóstico por las complicaciones renales (urolitiasis) u óseas (osteítis fibrosa quística) asociadas. Un tumor benigno de la glándula paratiroides (adenoma único), es la principal causa de esta enfermedad. Por tanto, su tratamiento usualmente es quirúrgico. A pesar de ello, no es frecuente el manejo de esta patología por el cirujano general. En este artículo se revisan conceptos claves para el diagnóstico y manejo de esta enfermedad para el médico residente y especialista en Cirugía general.

Calcium-mediated parathyroid hormone suppression test in uraemic secondary hyperparathyroidism

AIM

The present study aimed to investigate the value of calcium-mediated parathyroid hormone (PTH) suppression test in evaluating the autonomic secretory function of parathyroid, and the management of uraemic secondary hyperparathyroidism (SHPT).

METHODS

Calcium-mediated PTH suppression test was performed in dialysis with SHPT, who were candidates for parathyroidectomy from June 2017 to December 2019 in our hospital. The PTH inhibition rate (PTH-IR) was calculated, and the correlation between PTH-IR and clinical indicators was explored.

RESULTS

Fifty-one subjects were included. PTH-IR was negatively correlated with baseline PTH (r = -0.35, P = .012), it was also correlated with dialysis years, coronary artery calcification score (CACS) and parathyroid mass (r = -0.397, P = .004; r = -0.327, P = .028; r = -0.363, P = .015), which were not found for baseline PTH. Forty-four patients underwent surgical treatment. According to the histological results, 26 patients presented with parathyroid non-nodular hyperplasia, and 18 patients presented with parathyroid nodular hyperplasia. The mass of parathyroid of patients with nodular hyperplasia was higher than that of patients with non-nodular hyperplasia (ρ = 0.01). The difference of the PTH-IR was not found between the two groups (ρ = 0.296). During the test, the highest serum calcium was 2.9 ± 0.4 mmol/L, which dropped to normal at the end of the test.

CONCLUSION

Parathyroid hormone inhibition rate might be a useful indicator in evaluating the autonomic secretory function of parathyroid and the progression of SHPT on top of intact PTH. Calcium-mediated PTH suppression test was safe in uraemic SHPT patients, but need to monitor for transient hypercalcaemia.

Influence of Parathyroidectomy on Kidney Graft Function in Secondary and Tertiary Hyperparathyroidism

BACKGROUND

Timing of parathyroidectomy (PTX) remains controversial in candidates for kidney transplant with concomitant renal hyperparathyroidism (HPT). The aim of this retrospective study was to identify the influence of early vs late posttransplant PTX compared to pretransplant PTX on renal graft function and morbidity.

METHODS

This single-center cohort study includes 57 patients with renal HPT and kidney transplantation treated between 2007 and 2017. Ninety-six patients had surgery for renal HPT between 2007 and 2017 as a consecutive sample. Group 1 (n = 30; tertiary HPT), group 2 (n = 66; secondary HPT). Of group 1, 4 patients were excluded for PTX before and after kidney transplantation. In group 2, 20 patients were excluded since they had not undergone kidney transplantation during follow-up. Twelve patients were excluded because of short follow-up (kidney transplantation in 2018), and 3 patients were excluded because of transplant failure within 90 days. Twenty-six patients underwent posttransplant PTX (10 patients within 12 months after transplant), and 31 patients had undergone PTX prior to kidney transplantation. Graft function, serum calcium concentrations, parathyroid hormone (PTH) levels, postoperative morbidity, and 90-day mortality were recorded.

RESULTS

Median age was 53.1 years in group 1 and 49.1 years in group 2. Most patients were male (53.8% in group 1; 54.8% in group 2). Median preoperative PTH levels were significantly different with 331.6 pg/mL in group 1 and 667.5 pg/mL in group 2 (P = .003). Creatinine levels changed little from 1.4 mg/dL (range, 0.8-2.5) to 1.7 mg/dL (range, 0.7-7.3) in group 1, and no difference was seen between early or late PTX after transplantation. In group 2, creatinine levels were 8.5 mg/dL (range, 4.6-11.7) before PTX and 8.7 mg/dL (range, 5.1-11.9) after PTX. We saw no correlation between postoperative PTH and kidney function. Thirty-five patients with postoperative PTH < 15 pg/mL displayed a mean postoperative creatinine of 5.5 mg/dL (range, 4.3-6.8), similar to other patients. Both the 30-day and 90-day mortality rates were zero.

CONCLUSIONS

PTX had no negative effect on graft function, whether performed before or after (early or late) kidney transplantation. Surgical cure of renal HPT should be performed as soon as possible to prevent secondary complications and can also be safely carried out early after transplantation.

Risk-factors for nodular hyperplasia of parathyroid glands in sHPT patients

Introduction

Nodular hyperplasia of parathyroid glands (PG) is the most probable cause of medical treatment failure in secondary hyperparathyroidism (sHPT). This prospective cohort study is located at the interface of medical and surgical consideration of sHPT treatment options and identifies risk-factors for nodular hyperplasia of PG.

Material and methods

One-hundred-eight resected PG of 27 patients with a broad spectrum of sHPT severity were classified according to the degree of hyperplasia by histopathology. Twenty routinely gathered parameters from medical history, ultrasound findings of PG and laboratory results were analyzed for their influence on nodular hyperplasia of PG by risk-adjusted multivariable binary regression. A prognostic model for non-invasive assessment of PG was developed and used to weight the individual impact of identified risk-factors on the probability of nodular hyperplasia of single PG.

Results

Independent risk-factors for nodular hyperplasia of single PG were duration of dialysis in years, PG volume in mm³ determined by ultrasound and serum level of parathyroid hormone in pg/mL. Multivariable analyses computed a model with an Area Under the Receiver Operative Curve of 0.857 (95%-CI:0.773–0.941) when predicting nodular hyperplasia of PG. Theoretical assessment of risk-factor interaction revealed that the duration of dialysis had the strongest influence on the probability of nodular hyperplasia of single PG.

Conclusions

The three identified risk-factors (duration of dialysis, PG volume determined by ultrasound and serum level of parathyroid hormone) can be easily gathered in daily routine and could be used to non-invasively assess the probability of nodular hyperplasia of PG. This assessment would benefit from periodically collected data sets of PG changes during the course of sHPT, so that the choice of medical or surgical sHPT treatment could be adjusted more to the naturally changing type of histological PG lesion on an individually adopted basis in the future.

Vitamin D-Mediated Hypercalcemia: Mechanisms, Diagnosis, and Treatment

Hypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)₂D], and impaired degradation of 1,25(OH)₂D. The ingestion of excessive amounts of vitamin D₃ (or vitamin D₂) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)₂D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)₂D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)₂D is impaired as a result of mutations of the 1,25(OH)₂D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)₂D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)₂D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)₂D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment.

Subtotal parathyroidectomy for secondary renal hyperparathyroidism: a 20-year surgical outcome study

Aim

The aim of this study was to evaluate the outcomes of surgery for patients with secondary renal hyperparathyroidism (rHPT).

Methods

This is a retrospective cohort study. Our institutional database was searched for eligible patients treated in 1995–2014. The inclusion criterion was initial parathyroidectomy for rHPT. Clinical and follow-up data were analyzed to estimate the cure rate (primary outcome), and morbidity (secondary outcome).

Results

The study group comprised 297 patients (154 females, age 44.5 ± 13.7 years, follow-up 24.6 ± 10.5 months), including 268 (90.2 %) patients who had underwent subtotal parathyroidectomy, and 29 (9.8 %) who had had incomplete parathyroidectomy. Intraoperative iPTH assay was utilized in 207 (69.7 %) explorations. Persistent rHPT occurred in 12/268 (4.5 %) patients after subtotal parathyroidectomy and 5/29 (17.2 %) subjects after incomplete parathyroidectomy (p = 0.005). The patients operated on with intraoperative iPTH assay had a higher cure rate than non-monitored individuals, 201/207 (97.1 %) vs. 79/90 (87.8 %), respectively (p = 0.001). In-hospital mortality occurred in 1/297 (0.3 %) patient. The hungry bone syndrome occurred in 84/268 (31.3 %) patients after subtotal parathyroidectomy and 2/29 (6.9 %) subjects after incomplete parathyroidectomy (p = 0.006). Transient recurrent laryngeal nerve paresis occurred in 14/594 (2.4 %) and permanent in 5/594 (0.8 %) nerves at risk.

Conclusions

Subtotal parathyroidectomy is a safe and efficacious treatment for patients with rHPT. Utilization of intraoperative iPTH assay can guide surgical exploration and improve the cure rate.

Clinicopathological correlates of hyperparathyroidism

Hyperparathyroidism is a common endocrine disorder with potential complications on the skeletal, renal, neurocognitive and cardiovascular systems. While most cases (95%) occur sporadically, about 5% are associated with a hereditary syndrome: multiple endocrine neoplasia syndromes (MEN-1, MEN-2A, MEN-4), hyperparathyroidism-jaw tumour syndrome (HPT-JT), familial hypocalciuric hypercalcaemia (FHH-1, FHH-2, FHH-3), familial hypercalciuric hypercalcaemia, neonatal severe hyperparathyroidism and isolated familial hyperparathyroidism. Recently, molecular mechanisms underlying possible tumour suppressor genes (MEN1, CDC73/HRPT2, CDKIs, APC, SFRPs, GSK3β, RASSF1A, HIC1, RIZ1, WT1, CaSR, GNA11, AP2S1) and proto-oncogenes (CCND1/PRAD1, RET, ZFX, CTNNB1, EZH2) have been uncovered in the pathogenesis of hyperparathyroidism. While bi-allelic inactivation of CDC73/HRPT2 seems unique to parathyroid malignancy, aberrant activation of cyclin D1 and Wnt/β-catenin signalling has been reported in benign and malignant parathyroid tumours. Clinicopathological correlates of primary hyperparathyroidism include parathyroid adenoma (80-85%), hyperplasia (10-15%) and carcinoma (<1-5%). Secondary hyperparathyroidism generally presents with diffuse parathyroid hyperplasia, whereas tertiary hyperparathyroidism reflects the emergence of autonomous parathyroid hormone (PTH)-producing neoplasm(s) from secondary parathyroid hyperplasia. Surgical resection of abnormal parathyroid tissue remains the only curative treatment in primary hyperparathyroidism, and parathyroidectomy specimens are frequently encountered in this setting. Clinical and biochemical features, including intraoperative PTH levels, number, weight and size of the affected parathyroid gland(s), are crucial parameters to consider when rendering an accurate diagnosis of parathyroid proliferations. This review provides an update on the expanding knowledge of hyperparathyroidism and highlights the clinicopathological correlations of this prevalent disease.

The efficacy of low and high dose (99m)Tc-MIBI protocols for intraoperative identification of hyperplastic parathyroid glands in secondary hyperparathyroidism

OBJECTIVE

The aim of this study was to compare the efficacy of low- and high-dose (99m)Tc-MIBI protocols for intraoperative identification of hyperplastic parathyroid glands via gamma probe in secondary hyperparathyroidism.

MATERIAL AND METHODS

This retrospective study was conducted using a prospective database of 59 patients who had undergone radioguided subtotal parathyroidectomy between 2004-2012. The patients were studied in 2 groups. Group 1 (n=31) received 37 MBq (99m)Tc-MIBI intravenously in the surgical room approximately 10 min before the beginning of the intervention and surgery was performed under gamma probe guidance. Group 2 (n=28) received 555 MBq (99m)Tc- MIBI intravenously 2h before surgery, which was also performed under gamma probe guidance. Intraoperative gamma probe findings, laboratory findings, and histopathological findings were evaluated together.

RESULTS

Using acceptance of the histopathological findings as gold standard, sensitivity and specificity of intraoperative gamma probe for identifying hyperplastic parathyroid glands was 98% and 100%, respectively, in both groups.

CONCLUSIONS

In the light of these findings, it is concluded that the low-dose (99m)Tc-MIBI protocol might be preferable for intraoperative identification of hyperplastic parathyroid glands in secondary hyperparathyroidism patients because it was observed to be as effective as the high-dose (99m)Tc-MIBI protocol. Furthermore, the low-dose protocol does not have the disadvantages that are associated with the high-dose protocol.

Impact of parathyroidectomy on allograft outcomes in kidney transplantation

We performed retrospective, multi-center study of the impacts of parathyroidectomy (PTX) after or before kidney transplantation on allograft outcomes. A total of 63 patients who underwent PTX after kidney transplantation were identified. Deterioration in eGFR by more than 25% at 1 month after PTX occurred in 20% of the patients. The baseline eGFR was significantly lower in impairment group than nonimpairment group [adjusted odds ratio (OR) 0.87, 95% confidence interval (CI) 0.77-0.99, P = 0.033]. Low iPTH concentration after PTX was also a significant risk factor for the renal impairment (OR 0.96, CI 0.94-0.99, P = 0.009). A total of 37 patients who underwent PTX before transplantation were identified. Thirty-six percent of the patients had persistent hyperparathyroidism by 1 year after transplantation. A high iPTH level before PTX was a significant risk factor for persistent post-transplant hyperparathyroidism (adjusted OR 1.002, CI 1.000-1.005, P = 0.039). Finally, eGFR values during the first 5 years after transplantation were significantly lower in the patients who underwent PTX at less than 1 year after transplantation, than the pretransplant PTX patients (P = 0.032). As PTX after kidney transplantation has a risk of deterioration of allograft function, pretransplant PTX should be considered for patients with severe hyperparathyroidism, who could undergo post-transplant PTX.

Cinacalcet effects on the perioperative course of patients with secondary hyperparathyroidism

PURPOSE

Since its registration in 2004, the calcimimetic agent cinacalcet has been established as an alternative treatment for secondary hyperparathyroidism (SHPT). Working by allosteric activation of the calcium-sensing receptor, cinacalcet can lower parathyroid hormone (PTH) and calcium (Ca) in patients with SHPT. The influence of calcimimetics on the perioperative course has been unclear so far.

METHODS

We retrospectively analyzed the data of patients with primary operation for SHPT between 2004 and 2011, comparing the perioperative course of patients with and without preoperative cinacalcet treatment.

RESULTS

Fifty-six patients had cinacalcet therapy, and 54 patients had no calcimimetic medication prior to surgery. Gender, age, hemodialysis, and medical treatment were similar in both groups. Also, PTH levels were similar preoperatively and postoperatively (preoperative, 1,249 ± 676 vs. 1,196 ± 601 pg/ml; postoperative, 86 ± 220 vs. 62 ± 91 pg/ml). Patients with cinacalcet preoperatively had significant lower Ca levels preoperatively (2.49 ± 0.25 vs. 2.61 ± 0.24 mmol/l) and postoperatively (1.75 ± 0.37 vs. 1.86 ± 0.35 mmol/l) and had a higher rate of oral Ca substitution postoperatively (93 vs. 74 %). The risk for postoperative persistent disease was slightly higher in these patients compared to those without preoperative cinacalcet therapy (5 vs. 0 %, not significant).

CONCLUSIONS

In our experience, cinacalcet did not alter the perioperative course in SHPT patients.

Initial parathyroid surgery in 606 patients with renal hyperparathyroidism

BACKGROUND

The aim of the present study was to evaluate the outcome of different surgical procedures for patients on permanent dialysis who underwent initial parathyroidectomy for renal hyperparathyroidism (rHPT).

METHODS

Out of a prospective database of patients who underwent parathyroid surgery for rHPT between 1976 and 2009, patients on permanent dialysis who underwent initial parathyroidectomy were further analyzed regarding perioperative biochemical changes and postoperative outcome.

RESULTS

A total of 606 patients were analyzed. Total parathyroidectomy with autotransplantation (group A) was performed in 504 patients, total parathyroidectomy without autotransplantation in 32 (group B), subtotal parathyroidectomy in 21 (group C), and incomplete parathyroidectomy in 49 (group D). After surgery, mean calcium levels dropped from 2.76 to 1.91 mmol/l in group A, from 2.67 to 2.11 mmol/l in group B, from 2.70 to 2.09 mmol/l in group C, and from 2.65 to 1.94 mmol/l in group D. The parathyroid hormone level dropped from 1,371.4 pg/ml to 28.8 pg/ml in group A, from 1,078.4 pg/ml to 27.0 pg/ml in group B, from 2,377.9 pg/ml to 61.4 pg/ml in group C, and from 1,010.2 pg/ml to 99.5 pg/ml in group D. Persistent rHPT occurred in 2/504 patients from group A (0.4%), 0/32 patients from group B (0%), 1/21 patients from group C (4.8%), and 2/49 patients from group D (4.1%). After a mean follow-up of 57.6 months, recurrent rHPT occurred in 27/504 patients from group A (5.4%), in 0/32 patients from group B (0%), in 2/21 patients from group C (9.5%), and in 3/49 patients from group D (6.1%).

CONCLUSIONS

Total parathyroidectomy with or without autotransplantation is a feasible and safe surgical procedure for patients on permanent dialysis with otherwise uncontrollable rHPT.

Surgical treatment of tertiary hyperparathyroidism after renal transplantation: a 31-year experience in a single institution

Tertiary hyperparathyroidism (tHPT) most commonly refers to a persistent secondary hyperparathyroidism even after successful renal transplantation. Parathyroidectomy (PTX) is an efficient method for treatment of tHPT. In this study, we examined our 31-year experience with patients who underwent PTX for tHPT after KTX and assessed the effects of PTX on graft function according to the type of surgery. Among 2,981 recipients who underwent renal allograft between April 1979 and Dec. 2010, 15 patients (0.5%) were identified as having tHPT and underwent PTX. Levels of intact parathyroid hormone (iPTH) and serum calcium were measured before and after PTX for evaluation of the therapeutic effect, and glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease (MDRD) equation for investigation of any effect on graft function. One patient showed persistent hyperparathyroidism and hypercalcemia after limited PTX. We experienced 14 successful PTXs, including 3 total PTX with autotransplantations, 8 subtotal PTXs, and 3 limited PTXs. Level of iPTH and serum calcium were at normal range after PTX. Estimated GFR decreased after PTX. Total PTX with autotransplantation showed a tendency of more decrease in the values of iPTH, and GFR after PTX than Subtotal PTX. PTX can cure tHPT-specific symptoms and signs by recovery of hypercalcemia, but may carry the risk of deterioration of kidney graft function. We suspect that subtotal PTX, rather than total PTX with AT, prevent any risk of kidney graft deterioration in surgical treatment of tHPT, and, in selective tHPT patients, limited PTX might be recommended.

Unique expression pattern of the EMT markers Snail, Twist and E-cadherin in benign and malignant parathyroid neoplasia

BACKGROUND

Epithelial and mesenchymal transitions (EMT) are essential for embryonic development and progression of non-invasive tumor cells into malignant, metastatic carcinomas. During embryogenesis, the parathyroid glands develop from pharyngeal pouches and migrate to their final destinations, densely enclosed by mesenchymal neural crest cells. In this study, we examined the expression of the EMT markers Snail, Twist and E-cadherin in normal parathyroid glands and benign and malignant parathyroid diseases.

METHODS

Using immunohistochemistry, we compared expression of E-cadherin, Snail and Twist in 25 patients with parathyroid adenoma, 25 patients with parathyroid hyperplasia, and nine patients with parathyroid cancer with normal parathyroid glands.

RESULTS

Normal parathyroid glands, parathyroid adenomas, and parathyroid hyperplasias showed a typical membranous E-cadherin staining pattern. Expression of Snail was found in 22/25 parathyroid adenomas and in all parathyroid hyperplasias. Twist was expressed in 22/25 of parathyroid adenomas and in 20/25 parathyroid hyperplasias. Snail and Twist positive cells were homogeneously distributed throughout the gland. However, in all nine parathyroid carcinomas, membranous E-cadherin staining was lost. In addition, the expression pattern of Snail and Twist was changed and mostly limited to the invasive front of cancer tissue samples.

CONCLUSION

Expression of Snail and Twist at the invasive front and consecutive loss of E-cadherin in parathyroid carcinomas suggests a key role of EMT in the tumorigenesis of this cancer. The unique expression pattern could help to distinguish between an adenoma and a non-metastatic carcinoma. Loss of E-cadherin and change of the expression pattern of Snail and Twist together should result in an en bloc resection or a close follow-up.

[Evaluation of parathyroid function in presternal subcutaneous grafting after total parathyroidectomy for renal hyperparathyroidism]

INTRODUCTION

In the setting of total parathyroidectomy (TPT) and parathyroid transplantation (PTx) for renal hyperparathyroidism (RHP), we evaluated long-term parathyroid graft function after subcutaneous presternal transplantation (SCPTx).

HYPOTHESIS

Parathyroid glands are surrounded by fatty tissue. Therefore, we postulated that subcutaneous implantation of parathyroid tissue after TPT for RHP could be at least as effective as intramuscular grafting and would avoid the complications of the latter technique.

MATERIAL AND METHOD

We performed a study in a university hospital and its dialysis unit.

DESIGN

Prospective open efficacy study of a postoperative diagnostic monitoring method of intact parathyroid hormone (iPTH) in a cohort of surgical patients without loss to follow-up.

PATIENTS AND INTERVENTIONS

Thirty-five patients (19 women and 16 men) underwent TPT and SCPTx for RHP at the Department of General Surgery and Department of Nephrology, Donostia Hospital, San Sebastián, Gipuzkoa, Spain, from January 2002 to December 2005. Follow-up ranged from 6 to 42 months (mean, 15.4 months). Graft function was evaluated by measurement of plasma iPTH levels before surgery and 24 hours and 1, 3, 5, 15, 30, 60, 100 and 150 weeks after surgery. Reference values for PTH in our laboratory were 20-65 pg/mL.

RESULTS

The mean preoperative iPTH values were 1245 +/- 367.9 pg/mL (mean +/- SD) (range, 493-2160). After TPT and SCPTx, iPTH levels became undetectable in all patients at 24 hours. A value of 50 pg/mL was established as the criterion for adequate parathyroid graft function. The following values were obtained: 15.54 +/- 10.61 pg/mL (mean +/- SD) (range, 6-44) after 1 week, 57.2 +/- 1.9 pg/mL (mean +/- SD) (range, 43-74) after 5 weeks, 64.21 +/- 9.73 pg/mL (mean +/- SD) (range, 11.3-89) after 15 weeks, 75.12 +/- 9.05 pg/mL (mean +/- SD) (range, 24.6-104.2) after 30 weeks, 101.63 +/- 19.85 pg/mL (mean +/- SD) (range, 65-143) after 60 weeks, 121.63 +/- 27.85 pg/mL (mean +/- SD) (range, 62-179) after 100 weeks, 63 +/- 19.85 pg/mL (mean +/- SD) (range, 68-723) after 150 weeks and 102 +/- 18.65 pg/mL (mean +/- SD) (range, 68-113) after 200 weeks. The prevalence of hypoparathyroidism (serum iPTH level of < 20 pg/mL with a normal or low serum calcium concentration) was 2 out of 35 patients (5.71%) by week 60, with recovery of normal values by week 100. Graft-related recurrence occurred in one out of 35 patients (2.85%).

CONCLUSIONS

SCPTx after TPT and PTx for secondary RHP is an adequate method to replace muscular forearm parathyroid transplantation and avoid its complications. The functional results of TPT and SCPTx compare favorably with published data on other surgical techniques proposed for the treatment of RHP. Long-term follow-up of this series is currently being performed.

Comparison of total parathyroidectomy without autotransplantation and without thymectomy versus total parathyroidectomy with autotransplantation and with thymectomy for secondary hyperparathyroidism: TOPAR PILOT-Trial

BACKGROUND

Secondary hyperparathyroidism (sHPT) is common in patients with chronic renal failure. Despite the initiation of new therapeutic agents, several patients will require parathyroidectomy (PTX). Total PTX with autotransplantation of parathyroid tissue (TPTX+AT) and subtotal parathyroidectomy (SPTX) are currently considered as standard surgical procedures in the treatment of sHPT. Recurrencerates after TPTX+AT or SPTX are between 10% and 12% (median follow up: 36 months). Recent retrospective studies demonstrated a lower rate of recurrent sHPT of 0-4% after PTX without autotransplantation and thymectomy (TPTX) with no higher morbidity when compared to the standard procedures. The observed superiority of TPTX is flawed due to different definitions of outcomes, varying follow up periods and different surgical treatment strategies (with and without thymectomy).

METHODS/DESIGN

Patients with sHPT (intact parathyroid hormone > 10 times above the upper limit of normal) on long term dialysis (>12 months) will be randomized either to TPTX or TPTX+AT and followed for 36 months. Outcome parameters are recurrence rates of sHPT, frequencies of reoperations due to refractory hypoparathyroidism or recurrent/persistent hyperparathyroidism, postoperative morbidity and mortality and quality of life. 50 patients per group will be randomized in order to obtain relevant frequencies of outcome parameters that will form the basis for a large scale confirmatory multicentred randomized controlled trial.

DISCUSSION

sHPT is a disease with a high incidence in patients with chronic renal failure. Even a small difference in outcomes will be of clinical relevance. To assess sufficient data about the rate of recurrent sHPT after both methods, a multicentred, randomized controlled trial (MRCT) under standardized conditions is mandatory. Due to the existing uncertainties the calculated number of patients necessary in each treatment arm (n > 4000) makes it impossible to perform this study as a confirmatory trial. Therefore estimates of different outcomes are performed using a pilot MRCT comparing 50 versus 50 randomized patients in order to establish a hypothesis that can be tested thereafter. If TPTX proves to have a lower rate of recurrent sHPT, no relevant disadvantages and no higher morbidity than TPTX+AT, current surgical practice may be changed.

TRIAL REGISTRATION

International Standard Randomized Controlled Trial Number Registration (ISRCTN86202793).

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.

Parathyroid Subcutaneous Pre-sternal Transplantation after Parathyroidectomy for Renal Hyperparathyroidism. Long-term Graft Function

BACKGROUND

In the setting of total parathyroidectomy (TPT) and parathyroid transplantation (PTx) for renal hyperparathyroidism (RHP), we evaluated long-term parathyroid graft function after subcutaneous pre-sternal transplantation (SCPTx). Because parathyroid glands are surrounded by fatty tissue, we postulated that results of subcutaneous implantation of parathyroid tissue after total parathyroidectomy for renal hyperparathyroidism could be at least as successful as intramuscular grafting, but without its complications.

PATIENTS AND METHODS

The study, a prospective open efficacy study of postoperative (po) diagnostic monitoring of intact parathyroid hormone (iPTH) on a cohort of surgical patients, was conducted within a university hospital with a dialysis unit. Thirty five patients (19 women and 16 men) operated on for renal hyperparathyroidism underwent TPT and SCPTx for RHP at the Department of General Surgery and the Department of Nephrology. Donostia Hospital. San Sebastián. Gipuzkoa. Spain, from January 2002 to December 2005. Follow-up ranges from 6 months to 42 months (median: 15.4 months). The main outcome measure was evaluation of graft function by measurement of iPTH plasma level, based on serum levels of iPTH before operation and 24 h and 1, 3, 5, 15, 30, 60, 100, and 150 weeks after surgery.

RESULTS

Average preoperative iPTH values were 1,341.52 + 367.78 pg/ml (mean +/- SD) (range: 493-2,180). After TPT and PSCTx, iPTH levels became undetectable in all patients at 24 h. A level of 50 pg/ml was established as the criterion of adequate parathyroid graft function. Values obtained at the various time intervals were as follows: 14.14 + 7.73 1 pg/ml (mean +/- SD) (range: 6-36) after 1 week, 53 + 77.33 pg/ml (mean +/- SD) (range: 35-74) after 5 weeks, 62.95 + 20.93 pg/ml (mean +/- SD) (range: 11-89) after 15 weeks, 77.54 + 18.84 pg/ml (mean +/- SD) (range: 24.6-104.2) after 30 weeks, 109.29 + 50.22 pg/ml (mean +/- SD) (range: 54-327) after 60 weeks, 134.21 + 128.64 pg/ml (mean +/- SD) (range: 43-712) after 100 weeks, and 122.84 + 117.54 pg/ml (mean +/- SD) (range: 68-723) after 150 weeks. Prevalence of hypoparathyroidism (intact parathyroid hormone serum level < 20 pg/ml with a normal or low serum calcium concentration) was 2/35 (5.71%) by week 60 and recovered by week 100. Graft-related recurrence was 2.85% (1/35).

CONCLUSIONS

Subcutaneous pre-sternal transplantation (SCPTx) after TPT and PTx for secondary (RHP) is an adequate method to replace muscular forearm parathyroid transplantation and avoid its complications. Functioning results of total parathyroidectomy and presternal subcutaneous grafting compare favorably with the published data on other surgical techniques proposed for the treatment of renal hyperparathyroidism. Results of long-term follow-up exceed previously reported results.

Early and severe hyperparathyroidism associated with hypercalcemia after renal transplant treated with cinacalcet

Bone disease is a common clinical problem following renal transplantation. In renal transplant recipients, multiple underlying factors determine the extent of bone loss and the subsequent risk of fractures. In addition to the well-recognized risk to bone disease posed by steroids, calcineurin inhibitors and pre-existing bone disease, persistent hyperparathyroidism (HPT) contributes to post-transplant bone loss. HPT is usually treated with vitamin D supplements combined with calcium. Patients whose HPT is associated with hypercalcemia pose a difficult therapeutic dilemma which often requires parathyroidectomy. Cinacalcet, a calcium mimetic agent, offers a unique pharmacologic approach to the treatment of patients with post-transplant hypercalcemia and HPT. In this paper, we describe the clinical course and biochemical changes in 10 renal transplant recipients with hypercalcemia and severe HPT early after renal transplantation treated with cinacalcet. Cinacalcet therapy corrected hypercalcemia and decreased parathyroid hormone (PTH) levels in all cases. A transient rise in the level of alkaline phosphatase was noted following initiation of cinacalcet therapy. In this patient population, correction of HPT was not permanent as discontinuing cinacalcet therapy led to a rapid rise in PTH level.