Usefulness of a rapid immunometric assay for intraoperative parathyroid hormone measurements

Surgery for primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a hypercalcemic disorder that occurs when one or more parathyroid glands produces excessive parathyroid hormone (PTH). PHPT is typically treated with surgery, and it remains the only definitive therapy, whose techniques have evolved over previous decades. Advances in preoperative localization exams and the intraoperative PTH monitoring have become the cornerstones of recent parathyroidectomy techniques, as minimally invasive techniques are appropriate for most patients. Nevertheless, these techniques, are not suitable for PHPT patients who are at risk for multiglandular disease, especially in those who present with familial forms of PHPT that require bilateral neck exploration. This manuscript also explores other conditions that warrant special consideration during surgical treatment for PHPT: normocalcemic primary hyperparathyroidism, pregnancy, reoperation for persistent or recurrent PHPT, parathyroid carcinoma, and familial and genetic forms of hyperparathyroidism.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Secondary and Tertiary Renal Hyperparathyroidism

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate treatment of secondary (SHPT) and tertiary (THPT) renal hyperparathyroidism.

BACKGROUND

Hyperparathyroidism is common among patients with chronic kidney disease, end-stage kidney disease, and kidney transplant. The surgical management of SHPT and THPT is nuanced and requires a multidisciplinary approach. There are currently no clinical practice guidelines that address the surgical treatment of SHPT and THPT.

METHODS

Medical literature was reviewed from January 1, 1985 to present January 1, 2021 by a panel of 10 experts in SHPT and THPT. Recommendations using the best available evidence was constructed. The American College of Physicians grading system was used to determine levels of evidence. Recommendations were discussed to consensus. The American Association of Endocrine Surgeons membership reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines present the epidemiology and pathophysiology of SHPT and THPT and provide recommendations for work-up and management of SHPT and THPT for all involved clinicians. It outlines the preoperative, intraoperative, and postoperative management of SHPT and THPT, as well as related definitions, operative techniques, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Preoperative and Perioperative Care, Surgical Planning and Parathyroidectomy, Adjuncts and Approaches, Outcomes, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal management of secondary and tertiary renal hyperparathyroidism.

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.

Value of Intraoperative Parathyroid Hormone Assay during Parathyroidectomy in Dialysis and Renal Transplant Patients with Secondary and Tertiary Hyperparathyroidism

BACKGROUND

In dialysis and renal transplant patients with secondary and tertiary hyperparathyroidism (HPT), the value of intraoperative parathyroid hormone (ioPTH) during parathyroidectomy (PTX) and its association with long-term PTH levels are unknown. The present study aims at evaluating the relationship of ioPTH with long-term PTH levels post-PTX in dialysis and renal transplant patients in a single-center study.

METHODS

The ioPTH was measured in 57 dialysis patients (33 females and 24 males) and 18 renal transplant recipients (12 males and 6 females) who underwent PTX from 2005 to 2015 for refractory HPT. Near-total PTX was performed in 56 patients and total PTX with autotransplantation in 20 patients. The PTH monitoring included 3 samples: pre-intubation, 10- and 20-min (pre-ioPTH, 10-ioPTH, and 20-ioPTH) post parathyroid gland excision. Patients were followed up for up to 5 years.

RESULTS

In the dialysis group, the median (25th-75th percentile) pre-, 10-, and 20-ioPTH levels were 1,447 pg/mL (938-2,176), 143 pg/mL (78-244) and 112 pg/mL (59-153) respectively. In the renal transplant group, pre-, 10-, and 20-ioPTH levels were 273 pg/mL (180-403), 42 pg/mL (25-72), and 34 pg/mL (23-45) respectively. All patients in the transplant group had a functional kidney transplant at the time of PTX with a median serum creatinine of 1.3 mg/dL (1.2-1.7) and estimated glomerular filtration rate of 55 mL/min (40-60). The median time between renal transplant and PTX surgeries was 22 months (7-81). The last median follow-up PTH level was 66 pg/mL (15-201) in the dialysis group and 54 pg/mL (17-72) in the transplant group (p = 0.438). The mean time for last PTH post-PTX was 2.3 ± 2.0 years. In both groups, there was no significant difference between 20-ioPTH and any-time post-PTX PTH levels (p = 0.6 and p = 0.9). Nineteen patients (25%) were readmitted within 90 days because of hypocalcemia. One patient in the dialysis group was readmitted for post-PTX hematoma evacuation. No patient required repeat PTX because of recurrent HPT that was refractory to medical therapy. Only one dialysis patient required repeat PTX because the first procedure failed.

CONCLUSIONS

The 20-ioPTH is a good indicator of long-term PTH levels in dialysis and renal transplant patients. Hypocalcemia is a common complication, particularly in dialysis patients, and it is the main reason for readmission after PTX. Hypoparathyroidism is a potential concern after PTX in dialysis patients.

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.

A relationship between vitamin D, parathyroid hormone, calcium levels and lactose intolerance in type 2 diabetic patients and healthy subjects

BACKGROUND

Type 2 diabetes mellitus is chronic metabolic disorder. Common gastrointestinal symptoms in type 2 diabetic patients are flatulence, constipation and/or diarrhea. Reason for these may be lactose intolerance leading to change in vitamin D, Calcium and parathyroid hormone which further regulate bone mineralization.

AIM

To measure lactose intolerance, vitamin D, calcium and parathyroid hormone in type 2 diabetic patients.

MATERIAL AND METHODS

150 type 2 diabetic patients attending Endocrinology Clinic in PGI, Chandigarh and 150 age and sex matched healthy controls were enrolled. Lactose intolerance was measured using non-invasive lactose breath test. 25-hydroxyvitamin D (total) and Parathyroid hormone were measured in plasma using immunoassay. Serum calcium was measured using auto analyzer. T score was recorded from DXA scan for bone mineral density measurement.

RESULTS

Lactose intolerance was observed significantly higher (p<0.001) diabetic patients (59.3%) as compared to controls (42%). Levels of plasma 25-OH vitamin D (total), parathyroid hormone and serum calcium were significantly lower in patients as compared to controls. Furthermore, levels of plasma 25-OH vitamin D (total), parathyroid hormone and serum calcium were more decreased in lactose intolerant diabetic patients than lactose tolerant patients. Sixty seven percent (67%) of diabetic patients suffered from osteoporosis and 20% of controls. Eighty percent (80%) diabetic patients and 16% controls with osteoporosis suffered from lactose intolerance.

CONCLUSION

From this study we can conclude that measurement of lactose intolerance using non-invasive lactose breath test is suggested for type 2 diabetic patients along with timely measurement of 25-OH vitamin D (total), calcium and parathyroid hormone levels.

Autotransplant tissue selection criteria with or without stereomicroscopy in parathyroidectomy for treatment of renal hyperparathyroidism

Introduction

Several methods have been proposed to improve operative success in renal hyperparathyroidism.

Objective

To evaluate stereomicroscopy in parathyroid tissue selection for total parathyroidectomy with autotransplantation in secondary (SHPT)/tertiary (THPT) hyperparathyroidism.

Methods

118 renal patients underwent surgery from April of 2000 to October 2009. They were divided into two groups: G1, 66 patients operated from April of 2000 to May of 2005, with tissue selection based on macroscopic observation; G2, 52 patients operated from March of 2008 to October 2009 with stereomicroscopy for tissue selection searching for the presence of adipose cells. All surgeries were performed by the same surgeon. Patients presented SHPT (dialysis treatment) or THPT (renal-grafted). Follow-up was 12–36 months. Intra-operative parathyroid hormone (PTH) was measured in 100/118 (84.7%) patients.

Results

Data are presented as means. G1 included 66 patients (38 SHPT, 24 females/14 males; 40.0 years of age; 28 THPT, 14 females/14 males; 44 years of age). G2 included 52 patients (29 SHPT, 11 females/18 males; 50.7 years of age; 23 THPT, 13 females/10 males, 44.4 years of age). SHPT patients from G2 presented preoperative serum calcium higher than those of SHPT patients in G1 (p < 0.05), suggesting a more severe disease. Definitive hypoparathyroidism was found in seven of 118 patients (5.9%). Graft-dependent recurrence occurred in four patients, two in each group. All occurred in dialysis patients.

Conclusion

Stereomicroscopy in SHPT/THPT surgical treatment may be a useful tool to standardize parathyroid tissue selection.

Intraoperative PTH cutoff definition to predict successful parathyroidectomy in secondary and tertiary hyperparathyroidism

In order to improve success rates in surgery of renal hyperparathyroidism, we evaluated intraoperative PTH (IOPTH) measurement utility.

Method

86 patients underwent total parathyroidectomy with intramuscular presternal autotransplantation from 04/2000 to 10/2009 and were followed for 26.5 months on average (prospective cohort). Patients were divided in secondary (SHPT) and tertiary hyperparathyroidism (THPT). SHPT group was composed by patients under dialysis treatment, THPT group included renal grafted ones. IOPTH (Elecsys-PTH-Immunoassay/Roche) was measured at anesthesia induction (IOPTH-0’) and 20 minutes (IOPTH-20’) after parathyroidectomy.

Results

80.2% (69/86) presented with 80% decrease or more in the IOPTH-20’ and all were cured. In 11/86 patients (12.7%), a lower IOPTH-20’ drop (70-79%) was observed, and 2 of them (18.1%) failed to cure. 6/86 (6.9%) patients presented IO-PTH-20’ decrease of less than 70%: two were cured, in three a supernumerary/ectopic parathyroid was found and removed, and in one of these six patients, surgery was finished after 4-gland excision and the patient failure to cure.

Conclusion

IOPTH-20’ decrease of 80% or more compared to IOPTH-0’ predicts cure in all renal patients throughout follow-up. A decay of less than 70% points to missed or hyperfunctioning supernumerary gland and is predictive of surgical failure in 66.6%. A marginal IOPTH drop of 70-79% leaves the decision whether or not surgery should be continued up to the experienced surgeon.

A 10-year experience in intraoperative parathyroid hormone measurements for primary hyperparathyroidism: a prospective study of 91 previous unexplored patients

Introduction. Primary hyperparathyroidism (PHP) is characteristically determined by high levels of calcium and high or inappropriate levels of parathyroid hormone (PTH). Technological advances have dramatically changed the surgical technique over the years once intraoperative parathyroid hormone (IOPTH) assay had allowed for focused approaches. Objective. To evaluate our 10-year experience in employing a rapid intraoperative PTH assay for PHP. Methods. A prospective cohort of 91 PHP-operated patients in a tertiary institution in São Paulo, Brazil, from June 2000 to April 2011. Results. We had 85 (93.4%) successful parathyroidectomies, 6 (6.6%) failed parathyroidectomies in 91 previous unexplored patients, and 5 (100%) successful remedial surgeries. The IOPTH was true-positive in 88.5%, true-negative in 7.3%, false-positive in 2.1%, and false-negative in 2.1% of the procedures. IOPTH was able to obviate additional exploration or to ask for additional exploration in 92 (95.8%) procedures. Conclusion. The IOPTH revealed to be an important technological adjunct in the current parathyroid surgery for PHP.

Total parathyroidectomy with presternal intramuscular autotransplantation in renal patients: a prospective study of 66 patients

Surgical treatment of secondary (SHPT) and tertiary hyperparathyroidism (THPT) may involve various surgical approaches. The aim of this paper was to evaluate presternal intramuscular autotransplantation of parathyroid tissue as a surgical option in SHPT and THPT treatment. 66 patients with renal chronic disease underwent surgery from April 2000 to April 2005 at Universidade Federal São Paulo, Brazil. There were 38 SHPT patients (24 women/14 men), mean age of 39.yrs (range: 14-58), and 28 THPT patients (14 women/14 men), mean age of 43.4 yrs (range: 24-62). Postoperative average followup was 42.9 months (range: 12-96). Postoperative intact PTH increased throughout followup from 73.5 pg/mL to 133 pg/mL on average from 1st to the 5th year, respectively, in SHPT and from 54.9 pg/mL to 94.7 pg/mL on average from 1st to 5th year, respectively, in THPT group. Definitive hypoparathyroidism was observed in 4 (6.06%) patients and graft-dependent recurrence in 6 (9.09%). Presternal intramuscular autotransplantation of parathyroid tissue is a feasible and safe surgical option in SHPT and THPT treatment.

Utilidade da medida de PTH intra-operatório no tratamento cirúrgico do hiperparatiroidismo primário e secundário: análise de 109 casos

INTRODUÇÃO: A medida de PTH intra-operatório (PTH-IO) foi inicialmente descrita em 1988, sendo potencialmente útil na definição de sucesso após a paratiroidectomia. OBJETIVOS: Avaliar prospectivamente perfil de decaimento do PTH-IO e sua capacidade de prever sucesso cirúrgico no hiperparatiroidismo primário (HPP) e secundário à insuficiência renal (HPS). PACIENTES E MÉTODOS: 109 pacientes operados entre 06/2000 e 12/2004, sendo 33 HPP, 76 HPS (52 em diálise, 24 transplantados renais). PTH-IO: método imunométrico rápido (Elecsys-PTH/Immunoassay-Roche); tempo para resultado: 10 minutos. Coletas de sangue periférico nos tempos basal, 10 e 20 minutos pós-paratiroidectomia. RESULTADOS: HPP: queda média de PTH de 79,2% aos 10 minutos. HPS: queda média de PTH de 85,8% e 87,6% aos 10 minutos nos pacientes diálise e transplantados respectivamente. A cirurgia foi bem sucedida em todos, exceto em 2 pacientes (1 HPP, 1 HPS). Em ambos não houve queda PTH-IO, sendo constatado adenoma duplo no HPP e paratiróide ectópica no HPS. CONCLUSÃO: Medida PTH-IO fornece resultados confiáveis em tempo rápido, sendo capaz de discriminar persistência da doença se mantidos níveis elevados.

From mild to severe primary hyperparathyroidism: the Brazilian experience

Primary hyperparathyroidism often presents as an asymptomatic disorder. In our institution, routine serum calcium measurements have now been used as part of medical examination for 23 years. Out of 124 patients consecutively seen at our institution, 47% presented with no symptoms related to the disease, while 25% presented with severe skeletal involvement and osteitis fibrosa cystica, 25% with renal stone disease without overt bone involvement, and 2% with the typical neuropsychiatric syndrome. This same pattern is seen in the city of São Paulo. In severe disease pathological fractures are frequently seen, especially in long bones of the lower extremities, and also loss of lamina dura of the teeth and salt-and-pepper appearance of the skull. Bone mineral density is extremely low in these patients but usually show remarkable recovery following surgical cure. Serum PTH and bone markers are considerable higher in severely affected patients, who also have a high rate of vitamin D deficiency, and the parathyroid lesion is easier located compared with asymptomatic patients. From pathological specimens 87% had histological confirmation of a single adenoma, 6.4% multiple gland hyperplasia and 3.8% carcinoma.

The role of intraoperative parathyroid hormone testing in patients with tertiary hyperparathyroidism after renal transplantation

BACKGROUND

Intraoperative parathyroid hormone (PTH) testing has been shown to accurately define adequacy of parathyroid resection in patients with primary hyperparathyroidism (HPT) and alters the operative management in 10% to 15% of cases. However, the benefit of this technique in patients with tertiary HPT after renal transplantation undergoing parathyroidectomy is unclear.

METHODS

Intraoperative PTH was measured in 32 consecutive patients undergoing parathyroidectomy for tertiary HPT after renal transplantation between March 2001 and November 2004 by using the Elecsys assay at baseline and, subsequently, 5, 10, and 15 minutes after curative resection. The outcomes of these patients were evaluated.

RESULTS

All patients were cured after surgery. Of the 32 patients, 29 were found to have parathyroid hyperplasia, while 1 had a single adenoma and 2 had double adenomas. The average drop in intraoperative PTH levels after curative resection was 69 +/- 3.5% at 5 min., 77 +/- 2.3% at 10 minutes, and 83 +/- 3.4% at 15 minutes. PTH testing changed the intraoperative management in 5 (16%) patients. One patient with a single adenoma and 2 patients with double adenomas had a >50% drop at 10 minutes. after excision; therefore, the operation was terminated without further resection. Two patients did not have a >50% drop at 10 minutes after 3.5 gland resection. These patients were explored further, and additional supernumerary parathyroid glands were identified and resected. After resection of these additional glands, the PTH fell by >50%, indicating cure.

CONCLUSIONS

In patients undergoing parathyroidectomy for tertiary HPT after renal transplantation, a decrease in intraoperative PTH levels >50% at 10 minutes after completion of the operation indicated adequate resection. Furthermore, intraoperative PTH testing altered the operative management in 16% of patients. Therefore, similar to its role in patients with primary HPT, intraoperative PTH testing appears to play an equally important role in the management of patients with tertiary HPT undergoing parathyroidectomy.

[Parathyroid hormone values obtained with immunometric assays depend on the amino-terminal antibody specificity]

Introduction of 2nd generation immunometric assays for the measurement of serum parathyroid hormone (PTH), turned them more available, simple and rapid. These methods, based on double identification of the PTH molecule, supposedly measure the intact, bioactive molecule, with the sequence 1-84. Recent works showed that they also measure forms with amino-terminal deletions, like the 7-84 form, which are not able to activate the traditional PTH receptor (PTH1R). Thus, an important practical aspect is the definition of the PTH forms measured by the immunometric assays, a fact that depends on the specificity of the antibodies employed. In this report we compare the results obtained with an in-house immunofluorometric assay that presents a cross-reactivity of 50% with the 7-84 PTH sequence, and two commercial 2nd generation assays, that react 100%. In a first study, 135 samples were measured using our assay and an electrochemiluminescent assay, resulting in a correlation coefficient of 0.961 (P<0.0001) and medians of 35.0 and 51.0 ng/L (P<0.0001). In a second study, 252 samples were analyzed using our assay and an immunochemiluminometric assay, resulting in a correlation of 0.883 (P<0.0001) and medians of 36.0 and 45.5 ng/L (P<0.0001). In both studies results obtained with the in-house assay were significantly lower, as expected by the specificity of the anti-amino-terminal antibody employed. Our data support the need of a precise description of the specificity of the amino-terminal antibodies employed in 2nd generation PTH assays in order to better compare results and define normal ranges.