A comparison of surgical treatments for tertiary hyperparathyroidism. A systematic review

INTRODUCTION

Tertiary hyperparathyroidism develops in patients who have secondary hyperparathyroidism that persists despite successful kidney transplantation or in patients who are on chronic dialysis.

Impact of parathyroidectomy on kidney graft function in post-transplant tertiary hyperparathyroidism: a comparative study

PURPOSE

Parathyroidectomy to treat tertiary hyperparathyroidism (THPT) is now on a par with calcimimetic treatment. The effects of cinacalcet and parathyroidectomy on kidney transplant function remain controversial. The aim of this study was to evaluate kidney transplant function in THPT patients treated either by parathyroidectomy, cinacalcet, or not treated.

METHODS

Between 2009 and 2019, 231 patients with functional grafts presenting THPT, defined either by calcaemia superior to 2.5 mmol/L with elevated PTH level or hypercalcaemia with non-adapted PTH level 1 year after kidney transplantation, were included. Hyperparathyroid patients treated by cinacalcet and parathyroidectomy were matched for age, sex, graft rank, and baseline eGFR with cinacalcet-only and untreated patients. Conditional logistic regression models were used to compare eGFR variations 1 year after parathyroidectomy between operated patients and matched controls. Five-year survivals were compared with the Mantel-Cox test.

RESULTS

Eleven patients treated with parathyroidectomy and cinacalcet were matched with 16 patients treated by cinacalcet-only and 29 untreated patients. Demographic characteristics were comparable between groups. Estimated odds ratios for eGFR evolution in operated patients compared with cinacalcet-only and untreated patients were 0.92 [95%CI 0.83-1.02] and 0.99 [0.89-1.10] respectively, indicating no significant impairment of eGFR 1 year after surgery. Five-year allograft survival was not significantly impaired in operated patients.

CONCLUSIONS

Parathyroidectomy did not appear to substantially alter or improve graft function 1 year after surgery or 5-year allograft survival. It could be hypothesized that in addition to its known benefits, parathyroidectomy can be safely performed vis-à-vis graft function in tertiary hyperparathyroidism.

Parathyroidectomy or cinacalcet: Do we still not know the best option for graft function in kidney-transplanted patients? A meta-analysis

BACKGROUND

Tertiary hyperparathyroidism occurs in 25% to 50% of kidney-transplanted patients. Indication of parathyroidectomy is now discussed, since the calcimimetic agent, cinacalcet, is an alternate option. The effects of either of these treatments on graft function remain controversial, studied only in small cohorts showing either decrease or absence of modification. We performed a meta-analysis to evaluate the evolution of graft function after surgical or medical treatment.

METHODS

Studies assessing graft function in tertiary hyperparathyroidism after parathyroidectomy or cinacalcet introduction were enrolled into quantitative analysis using Pubmed, Embase, and Cochrane databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis reporting guidelines. Among 68 screened studies, 18 had no missing data and were included for statistical analyses. We performed random effect meta-analysis to determine changes in serum creatinine and estimated glomerular filtration rate.

RESULTS

Seven studies assessing the evolution of graft function 6 and/or 12 months after parathyroidectomy and 13 after administration of cinacalcet were included. Meta-analysis found no significant variations after parathyroidectomy in serum creatinine (6 studies, 314 patients) and estimated glomerular filtration rate (2 studies, 105 patients). No significant variation was found after administration of cinacalcet in serum creatinine (10 studies, 404 patients) and estimated glomerular filtration rate (6 studies, 149 patients). A significant heterogeneity between the studies (P < .01, Cochran's Q) was found.

CONCLUSION

Meta-analysis shows that parathyroidectomy and cinacalcet do not significantly impair graft function in patients with tertiary hyperparathyroidism. However, the significant heterogeneity between selected studies, partially explained by the lack of consensual definition of tertiary hyperparathyroidism, limits the conclusions of all previously published series.

Acute and long-term kidney function after parathyroidectomy for primary hyperparathyroidism

Background

In kidney transplant patients, parathyroidectomy is associated with an acute decrease in renal function. Acute and chronic effects of parathyroidectomy on renal function have not been extensively studied in primary hyperparathyroidism (PHPT).

Methods

This retrospective cohort study included 494 patients undergoing parathyroidectomy for PHPT. Acute renal changes were evaluated daily until day 4 post-parathyroidectomy and were stratified according to acute kidney injury (AKI) criteria. Biochemical assessment included serum creatinine, total and ionized calcium, parathyroid hormone (PTH), and 25-hydroxyvitamin D (25OHD). The estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI equation. We compared preoperative and postoperative renal function up to 5 years of follow-up.

Results

A total of 391 (79.1%) patients were female, and 422 (85.4%) were non-African American. The median age was 58 years old. The median (first and third quartiles) preoperative serum creatinine, PTH and total calcium levels were 0.81 mg/dL (0.68–1.01), 154.5 pg/mL (106–238.5), and 10.9 mg/dL (10.3–11.5), respectively. The median (first and third quartiles) preoperative eGFR was 86 mL/min/1.73 m² (65–101.3). After surgery, the median acute decrease in the eGFR was 21 mL/min/1.73 m² (p<0.0001). Acutely, 41.1% of patients developed stage 1 AKI, 5.9% developed stage 2 AKI, and 1.8% developed stage 3 AKI. The acute eGFR decrease (%) was correlated with age and PTH, calcium and preoperative creatinine levels in univariate analysis. Multivariate analysis showed that the acute change was related to age and preoperative values of ionized calcium, phosphorus and creatinine. The change at 12 months was related to sex, preoperative creatinine and 25OHD. Permanent reduction in the eGFR occurred in 60.7% of patients after an acute episode.

Conclusion

There was significant acute impairment in renal function after parathyroidectomy for PHPT, and almost half of the patients met the criteria for AKI. Significant eGFR recovery was observed during the first month after surgery, but a small permanent reduction may occur. Patients treated for PHPT seemed to present with prominent renal dysfunction compared to patients who underwent thyroidectomy.

Long-term renal graft outcome after parathyroidectomy - a retrospective single centre study

BACKGROUND

Surgical correction of hyperparathyroidism after kidney transplantation has been associated with significant graft function decline. We examined the effects of parathyroidectomy on short- and long-term graft function and its potential predictors.

METHODS

For this retrospective, monocentric study we identified 48 (5.5%) out of 892 patients from our protocol biopsy program who received renal transplantation between 2000 and 2007, with parathyroidectomy after transplantation. Data from up to three years after parathyroidectomy was collected and analyzed with multivariable linear regression analyses.

RESULTS

Main indications for parathyroidectomy were hypercalcemia and graft calcifications. Parathyroidectomy was successful in 47 patients, with a median drop in serum intact parathormone (iPTH) from 394 to 21 pg/ml. Mean estimated glomerular fitration rate (eGFR) before parathyroidectomy was 60 ± 26 ml/min. At three months after parathyroidectomy, the eGFR was 46 ± 18 ml/min (p < 0.001) but remained stable at one and three years (50 ± 20; 49 ± 20 ml/min). The median annual eGFR change was - 0.5 ml/min before and + 1.0 ml/min after parathyroidectomy. Multivariable modeling identified high iPTH levels and higher eGFR before parathyroidectomy as predictors of the eGFR drop after parathyroidectomy. Lower graft function twelve months after parathyroidectomy was predicted by the eGFR before and the iPTH drop after surgery.

CONCLUSIONS

These results indicate that the extent of parathyroidectomy is critical and too much lowering of iPTH should be avoided by timely parathyroidectomy, before reaching extreme high iPTH values. In view of the observed loss of eGFR, parathyroidectomy can be considered safe in patients with an eGFR above 30 ml/min.

Pattern of Intraoperative Parathyroid Hormone and Calcium in the Treatment of Tertiary Hyperparathyroidism

OBJECTIVE

Tertiary hyperparathyroidism, an autonomous hyperproduction of parathyroid hormone (PTH), has a challenge in its treatment. This study asked whether the intraoperative PTH and calcium drop can confirm the resection of all parathyroid tissues.

STUDY DESIGN

Case series with planned data collection.

SETTING

Tertiary referral medical center.

SUBJECTS AND METHODS

The study assessed patients with tertiary hyperparathyroidism who were treated at the Hospital of the State University of Campinas from 2007 to 2015. All patients underwent total parathyroidectomy with autotransplantation of parathyroid fragments. PTH and calcium were collected during the preoperative period; at 10, 20, and 240 minutes after resection of the glands; and at 1 year after the procedure. Data were analyzed by analysis of variance and logistic regression analysis with statistical values of P < .05.

RESULTS

Thirty-five patients were assessed: 17 women (48.57%) and 18 men (51.43%). The percentage of PTH drop was statistically significant at all times, unlike the calcium analysis, but only PTH collected at 20 minutes was able to confirm the removal of all parathyroid tissues (P = .029). Based on the receiver operating characteristic curve, the 71.2% drop obtained high sensitivity and specificity (P = .028).

CONCLUSIONS

Treatment success can be predicted by analyzing the decrease of intraoperative PTH and not by calcium. The 71.2% PTH drop at 20 minutes after parathyroidectomy had high sensitivity and specificity to predict surgical cure.

Timing of parathyroidectomy in kidney transplant candidates with secondary hyperparathryroidism: effect of pretransplant versus early or late post-transplant parathyroidectomy

BACKGROUND

The timing of parathyroidectomy in kidney transplant candidates suffering from secondary hyperparathyroidism before versus early or late after transplantation remains controversial.

METHODS

The short-term follow-up cohort comprised 66 patients with 1-year post-transplant follow-up, while the long-term follow-up cohort contained 123 patients. Risk-adjusted identification of independent risk factors for compromised renal graft function (KDIGO stage ≥ IV) was performed using multivariable regression analysis adjusted for propensity score logits for parathyroidectomy before versus after renal transplantation. Intra-individual matched-pairs analyses were used to identify significant effects of post-transplant parathyroidectomy on graft function as assessed by estimated glomerular filtration rate (eGFR) and paired t tests.

RESULTS

Donor kidney function KDIGO stage III (P = .030; OR = 5.191, 95% CI: 1.100-24.508), donor blood group 0 (P = .005; OR = 0.176, 95% CI: 0.048-0.642), and post-transplant parathyroidectomy (P = .032; OR = 17.849, 95% CI: 1.086-293.268) were revealed as independent significant risk factors for compromised renal graft function in the short-term follow-up cohort using propensity score risk adjustment while post-transplant parathyroidectomy had no independent influence in the long-term follow-up cohort (P = .651). Parathyroidectomy after renal transplantation compromised graft function early after parathyroidectomy and at last follow-up in all post-transplant parathyroidectomy cases (P ≤ .004). Parathyroidectomy within the first post-transplant year was associated with compromised renal graft function until last follow-up (P = .004), while parathyroidectomy late post-transplant was not.

CONCLUSION

Parathyroidectomy should be conducted before transplantation or, if this is not possible, preferably after the first post-transplant year.

Parathyroidectomy for tertiary hyperparathyroidism: A systematic review

OBJECTIVE

Analyze the efficacy and indications for parathyroidectomy as an intervention for tertiary hyperparathyroidism.

DATA SOURCES

PubMed, MEDLINE, and Cochrane Library databases.

REVIEW METHODS

A systematic literature search was performed using the. Original research articles in English were retrieved using the search terms ("tertiary hyperparathyroidism" OR "3HPT") AND "parathyroidectomy". Articles were analyzed in regards to their surgical indications, operative endpoints, comparison between different surgical interventions, characterization of disease recurrence rates, and evaluation of alternative medical management.

RESULTS

Thirty studies met the criteria for inclusion. Among the studies that report indications for parathyroidectomy, persistent hypercalcemia as well as clinical manifestations of hypercalcemia despite medical therapy predicted which patients would eventually need surgical intervention. The majority of studies comparing the extent of parathyroidectomy recommended a more focused approach to parathyroidectomy when warranted. All studies found that parathyroidectomy was an effective treatment for 3HPT. Three studies discussed alternative conservative approaches.

CONCLUSION

Interestingly, hyperparathyroidism alone is not an indication for surgery without other findings; rather, symptomatic hypercalcemia appears to be the main indication. Most studies recommend limited or subtotal parathyroidectomy for 3HPT. The operative endpoint of surgery is not necessarily a return of PTH to normal, but a >50% drop in PTH level even if PTH remains above normal. Additionally, "success" or "cure" is defined as normal calcium levels regardless of whether or not PTH is elevated. It appears the goal of surgery for 3HPT is not a normal PTH value, but a normal calcium level at least six months postoperatively.

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.

Presence of small parathyroid glands in renal transplant patients supports less-than-total parathyroidectomy to treat hypercalcemic hyperparathyroidism

BACKGROUND

Parathyroid glands (PG) are rarely analyzed in renal transplant (RTX) patients. This study analyzes comparatively PG of RTX and end-stage renal disease (ESRD) patients. The clinical part of the study evaluates if total parathyroidectomy with autotransplantation (TPT+AT) treats appropriately hypercalcemic hyperparathyroidism in RTX patients.

METHODS

TPT+AT was performed in 15 of 23 RTX and 21 of 27 ESRD patients. Remaining patients underwent less-than-total PT. Volume and stage of hyperplasia were determined from 86 PG of RTX and 109 PG of ESRD patients. Patients were categorized according to the presence of small PG (volume < 100 mm(3)). Calcium homeostasis and hyperparathyroidism were evaluated 2 years after PT in RTX patients.

RESULTS

PG of RTX patients were significantly smaller, but similar hyperplastic in comparison to PG of ESRD patients. Small PG were more frequent in RTX than in ESRD patients (19% vs 6%) and mainly graded normal or diffuse hyperplastic (94%). Forty-seven percent of RTX, but only 14% of ESRD, patients receiving a total PT possessed ≥1 small PG (P < .05). Overall, PT treated successfully hypercalcemic hyperparathyroidism. However, TPT+AT caused permanent hypocalcemia in 50% of RTX patients without small PG and even in 83% of RTX patients with small PG. All RTX patients receiving less-than-total PT were normocalcemic at 2-year follow-up. Logistic regression revealed a 10.7 times greater risk of permanent hypocalcemia in RTX patients with small PG receiving TPT+AT compared with RTX patients without small PG receiving TPT+AT or RTX patients undergoing less-than-total PT.

CONCLUSION

Surgeons performing PT should be aware of the high frequency of small and less diseased PG in RTX patients. In this context, TPT+AT might overtreat hypercalcemic hyperparathyroidism in RTX patients, especially when small PG are present.

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.