Total parathyroidectomy without autotransplantation in dialysis patients and renal transplant recipients, long-term follow-up evaluation

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.

Type of subtotal parathyroidectomy and evolution of parathyroid hormone levels in end-stage renal disease patients: a retrospective cohort study

PURPOSE

Parathyroidectomy (PTX) is performed in end-stage renal disease (ESRD) for the treatment of secondary hyperparathyroidism. Whether and how the number of glands removed affects parathyroid hormone (PTH) levels remain controversial. The objective of this study is to compare the biochemical and pharmacological evolution after subtotal PTX according to the number of glands removed in ESRD.

METHODS

This is a unicenter longitudinal retrospective cohort study of ESRD patients who have undergone PTX [< 3 glands (group 1) vs ≥ 3 glands (group 2)] from April 2006 to October 2014 at CHU de Québec, Canada. Demographic data, comorbidities, pharmacological and biochemical parameters were collected before, 3, 6, 12 and 24 months after PTX. Linear mixed model was performed to compare the biochemical and pharmacological evolution.

RESULTS

We included 37 (13 in group 1, 24 in group 2) ESRD patients with a median age of 53 (46-58) years. The population is 68% male with a median dialysis vintage of 30.7 (18.0-61.2) months. The two groups were similar in terms of demographics and comorbidities. Compared to baseline, PTH levels in groups 1 and 2 dropped significantly at 2 years (1239-361 ng/L and 1542-398 ng/L, p < 0.05) but the evolution was comparable between the two groups.

CONCLUSIONS

Our results show the efficacy of subtotal PTX in lowering PTH levels in our ESRD cohort. However, the results were not different according to the number of glands removed.

Mineral and Bone Disease in Kidney Transplant Recipients

PURPOSE OF REVIEW

Despite metabolic improvements following kidney transplantation, transplant recipients still often suffer from complex mineral and bone disease after transplantation.

RECENT FINDINGS

The pathophysiology of post-transplant disease is unique, secondary to underlying pre-transplant mineral and bone disease, immunosuppression, and changing kidney function. Changes in modern immunosuppression regimens continue to alter the clinical picture. Modern management includes reducing cumulative steroid exposure and correcting the biochemical abnormalities in mineral metabolism. While bone mineral density screening appears to help predict fracture risk and anti-osteoporotic therapy appears to have a positive effect on bone mineral density, more data regarding specific treatment is necessary. Patients with mineral and bone disease after kidney transplantation require special care in order to properly manage and mitigate their mineral and bone disease. Recent changes in clinical management of transplant patients may also be changing the implications on patients' mineral and bone disease.

Toxic and Endocrine Myopathies

PURPOSE OF REVIEW

This article discusses the clinical features, pathophysiology, and management of toxic and endocrine myopathies.

RECENT FINDINGS

Early detection and expeditious correction of metabolic disturbances in endocrinopathies such as Cushing syndrome, thyroid and parathyroid diseases, and acromegaly can minimize and prevent neurologic complications including myopathy. Recently proposed mechanisms of injury in patients with critical illness myopathy include inhibition of protein synthesis, mitochondrial dysfunction, disruption of the ubiquitin-proteasome system, oxidative stress, and disruption of intramuscular calcium homeostasis, which can cause a myosin-loss myopathy. Mechanisms underlying toxic myopathies include myosin loss; damage to cellular structures, including myofibrils and organelles such as lysosomes and mitochondria; inflammation; and necrosis. Presentations range anywhere from acute, painful, and necrotic myopathies, as can occur in statin myopathy, to more insidious presentations such as steroid myopathy.

SUMMARY

Endocrinopathies known to cause myopathy include thyroid and parathyroid diseases, disorders of the adrenal axis such as Cushing syndrome, and acromegaly. Patients in the intensive care unit are at risk for developing critical illness myopathy, also known as myosin-loss myopathy, which should be considered if intensive care unit acquired weakness develops. The most common toxic agents associated with myopathy include statins and other lipid-lowering medications, corticosteroids, colchicine, amiodarone, hydroxychloroquine, and chloroquine.

Subtotal Parathyroidectomy and Relocation of the Parathyroid Remnant for Renal Hyperparathyroidism: modification of a traditional operation

Background

We describe a modification of the conventional subtotal parathyroidectomy operation where the parathyroid gland(s) remnant is repositioned with intact vascular supply to a plane superficial to the infrahyoid strap muscles and immediately under the skin incision. This technique called Subtotal Parathyroidectomy and Remnant Relocation (SPARE) retains all the metabolic advantages of the conventional operation with the added advantage of easier identification of a recurrent hyperplastic remnant if re-exploration becomes necessary.

Methods

In the SPARE technique, four parathyroid glands were identified and the quality of each gland and the length of each vascular pedicle to the parathyroid glands were assessed. The optimal parathyroid gland was relocated to a plane superficial to the strap muscles. The remainder of the glands were removed.

Results

In total, 30 patients with hyperparathyroidism secondary to renal failure (HSRF) underwent parathyroidectomy with the SPARE technique. The mean age was 53.1±12.5 years and median follow-up was 17.1 months (range 1-78.9 months). There were no recurrent laryngeal nerve (RLN) injuries or hematomas. The pre- and post-operative value for corrected calcium and PTH were 158.4±109.4 pmol/L and 11.4±12.1 pmol/L, respectively (p < 0.05). Three recurrences were noted (10.0%), with a mean time to recurrence of 15.3±6.6 months. One patient had excision of the remnant parathyroid glands performed under local anaesthetic (29 min); one had re-exploration performed under general anaesthetic (81 min), and one was managed medically.

Conclusion

We described a novel parathyroidectomy technique for patients with HSRF, which provides the advantages of conventional subtotal parathyroidectomy while mitigating the challenges of thyroid bed re-exploration when recurrences arise.

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.

Does the Parathyroidectomy Endanger the Transplanted Kidney?

BACKGROUND

Some investigators maintain that a parathyroidectomy (PTX) performed for tertiary hyperparathyroidism may potentially cause graft malfunction or even loss of the transplanted kidney after the operation. The goal of this study was to determine if parathyroidectomy affects transplanted kidney function.

METHODS

The study group consisted of 48 renal graft recipients who underwent operation due to tertiary hyperparathyroidism. Thirty-nine subtotal parathyroidectomies and 9 more selective, less than subtotal parathyroidectomies were performed. The estimated glomerular filtration rate (eGFR) was calculated retrospectively on days 2 to 3 and 4 to 5 and at 1, 3, 6, 12, 24, and 36 months after PTX; these findings were compared with preoperative values. The cumulative graft survival rate in the postoperative period was assessed.

RESULTS

In the follow-up period, 4 of 48 patients returned to hemodialysis (after 1, 7, 22, and 57 months after PTX). In the first case, the patient had stopped taking the immunosuppressive drugs 1 month after PTX. Cumulative graft survival rate after PTX was 98.0% after 6 months, 96% after 12 months, and 93% after 2 and 3 years. The mean preoperative eGFR was 52 ± 17.15 mL/min/1.73 m(2), and the median was 48.28 mL/min/1.73 m(2). Overall and in the subtotal parathyroidectomy group, eGFR was significantly lower (P < .001) only on days 2 to 3. There were no differences between preoperative and postoperative eGFR values in the other follow-up periods. In the more selective, less than subtotal parathyroidectomy group, the decrease in eGFR values was nonsignificant compared with preoperative findings in the early postoperative period as well as in all follow-up periods.

CONCLUSIONS

In this study, PTX did not significantly impair transplanted kidney function, but in the early postoperative period, transient reductions in graft function did occur.

Surgical treatment of secondary hyperparathyroidism in elderly patients: an institutional experience

BACKGROUND

Secondary hyperparathyroidism in elderly fragile patients presents clinical difficulties due to severity of symptoms and related comorbidity. The optimal surgical approach for this group of patients is still debated.

AIM

The aim of the study was to define the optimal technique of parathyroidectomy in elderly patients with secondary hyperparathyroidism.

METHODS

Retrospective analysis in a series of 253 patients including 35 elderly individuals at a single institution was carried out. Postoperative parathyroid hormone decrease, surgical complications and symptoms control were analyzed for all patients in relation to the types of parathyroidectomy performed.

RESULTS

In elderly patients, total parathyroidectomy was the most used approach. Subtotal parathyroidectomy was mostly reserved for younger patients suitable for kidney transplantation. No elderly patients treated with total parathyroidectomy were autotransplanted. No significant difference in surgical complications was observed between younger and elderly patients and considering the different procedures. Adequate symptom control after surgery was achieved in almost 90% of patients. A limited rate of recurrence requiring repeat surgery was observed only after subtotal parathyroidectomy.

DISCUSSION

Considering the features of all types of parathyroidectomy, very low recurrence rate, contained postoperative hypocalcemia and limited complications following total parathyroidectomy, might represent specific advantages for elderly patients.

CONCLUSIONS

Total parathyroidectomy without parathyroid transplantation is safe for elderly patients with secondary hyperparathyroidism and a good alternative to the well-established total parathyroidectomy with autografting.

Surgical management of secondary hyperparathyroidism in chronic kidney disease--a consensus report of the European Society of Endocrine Surgeons

BACKGROUND

Despite advances in the medical management of secondary hyperparathyroidism due to chronic renal failure and dialysis (renal hyperparathyroidism), parathyroid surgery remains an important treatment option in the spectrum of the disease. Patients with severe and complicated renal hyperparathyroidism (HPT), refractory or intolerant to medical therapy and patients with specific requirements in prospect of or excluded from renal transplantation may require parathyroidectomy for renal hyperparathyroidism.

METHODS

Present standard and actual controversial issues regarding surgical treatment of patients with hyperparathyroidism due to chronic renal failure were identified, and pertinent literature was searched and reviewed. Whenever applicable, evaluation of the level of evidence concerning diagnosis and management of renal hyperparathyroidism according to standard criteria and recommendation grading were employed. Results were discussed at the 6th Workshop of the European Society of Endocrine Surgeons entitled Hyperparathyroidism due to multiple gland disease: An evidence-based perspective.

RESULTS

Presently, literature reveals scant data, especially, no prospective randomized studies to provide sufficient levels of evidence to substantiate recommendations for surgery in renal hyperparathyroidism. Appropriate surgical management of renal hyperparathyroidism involves standard bilateral exploration with bilateral cervical thymectomy and a spectrum of four standardized types of parathyroid resection that reveal comparable outcome results with regard to levels of evidence and recommendation. Specific patient requirements may favour one over the other procedure according to individualized demands.

CONCLUSIONS

Surgery for patients with renal hyperparathyroidism in the era of calcimimetics continues to play an important role in selected patients and achieves efficient control of hyperparathyroidism. The overall success rate and long-term control of renal hyperparathyroidism and optimal handling of postoperative metabolic effects also depend on the timely indication, individually suitable type of parathyroid resection and specialized endocrine surgery.

Changes in secondary hyperparathyroidism-related biochemical parameters and medication use following parathyroidectomy

BACKGROUND

Little is known about changes in parathyroid hormone (PTH), calcium and phosphorous levels after parathyroidectomy in hemodialysis patients. We studied the effects of parathyroidectomy on these biochemical values in a large cohort of patients receiving maintenance hemodialysis.

METHODS

This retrospective cohort study included patients identified in both the United States Renal Data System and the database of a large dialysis organization who underwent parathyroidectomy in 2007-09, were aged ≥ 18 years, had Medicare Parts A and B as primary payer and had received hemodialysis for ≥ 1 year pre-parathyroidectomy. Descriptive statistics were calculated for continuous variables; categorical variables were used to characterize the population and evaluate monthly laboratory and medication use; median values were calculated for laboratory measures.

RESULTS

Among 1402 parathyroidectomy patients, mean age was 48.9 years, 52.4% were males, 58.8% were African American and mean dialysis duration was 7.5 years. Median PTH levels increased over the year before parathyroidectomy from 1039 to 1661 pg/mL and decreased afterward to 98 pg/mL at 1 month; levels remained ≥ 897 pg/mL for 10% of patients. Median calcium levels fell from 9.6 mg/dL before to 7.9 mg/dL 1 month after parathyroidectomy; levels were ≤ 7.1 mg/dL for 25% and remained ≤ 7.2 mg/dL for the lowest 25% at 3 months. Median phosphorous level was 6.8 mg/dL immediately before parathyroidectomy, decreased to 3.8 mg/dL immediately after and reached 5.8 mg/dL at 1 year.

CONCLUSIONS

While PTH levels dropped after parathyroidectomy for most patients, surgery was sometimes ineffective in reducing levels and sometimes led to over-suppression. Hypocalcemia could be profound and long lasting, suggesting the need for prolonged vigilance.

Total parathyroidectomy with trace amounts of parathyroid tissue autotransplantation as the treatment of choice for secondary hyperparathyroidism: a single-center experience

Background

The aim of the study was to evaluate total parathyroidectomy with trace amounts of parathyroid tissue (30 mg) as a surgical option in secondary hyperparathyroidism (sHPT) treatment.

Methods

From January 2008 to March 2012, 47 patients underwent parathyroidectomy. Comparisons of demographic data, symptoms, and preoperative or postoperative biochemistry were made between total parathyroidectomy with trace amounts of parathyroid tissue autotransplantation group and total parathyroidectomy group.

Results

Out of 47 cases, 45 had successful operation. 187 parathyroid glands identified at the initial operation were reported in 47 patients. 43 patients had been diagnosed with parathyroid hyperplasia, and 4 patients had a benign adenoma. After operation, pruritus, bone pain and muscle weakness disappeared, also serum PTH and serum phosphate were declined markedly as well. After discharge, two patients (in total parathyroidectomy group) were readmitted because of postoperative hypoparathyroidism. Graft-dependent recurrence was not observed in an average follow-up of 42 months.

Conclusions

Total parathyroidectomy with sternocleidomastoid muscle trace amounts of parathyroid tissue autotransplantation is considered to be a feasible, safe and effective surgical option for the patients with sHPT.

Neurologic disorders of mineral metabolism and parathyroid disease

Disorders of mineral metabolism may cause neurologic manifestations of the central and peripheral nervous systems. This is because plasma calcium stabilizes excitable membranes in the nerve and muscle tissue, magnesium is predominantly intracellular and is required for activation of many intracellular enzymes, and extracellular magnesium affects synaptic transmission. This chapter reviews abnormalities in electrolytes and minerals which can be associated with several neuromuscular symptoms including neuromuscular irritability, mental status changes, cardiac and smooth muscle changes, etc.

CKD-mineral and bone disorder management in kidney transplant recipients

Kidney transplantation, the most effective treatment for the metabolic abnormalities of chronic kidney disease (CKD), only partially corrects CKD-mineral and bone disorders. Posttransplantation bone disease, one of the major complications of kidney transplantation, is characterized by accelerated loss of bone mineral density and increased risk of fractures and osteonecrosis. The pathogenesis of posttransplantation bone disease is multifactorial and includes the persistent manifestations of pretransplantation CKD-mineral and bone disorder, peritransplantation changes in the fibroblast growth factor 23-parathyroid hormone-vitamin D axis, metabolic perturbations such as persistent hypophosphatemia and hypercalcemia, and the effects of immunosuppressive therapies. Posttransplantation fractures occur more commonly at peripheral than central sites. Although there is significant loss of bone density after transplantation, the evidence linking posttransplantation bone loss and subsequent fracture risk is circumstantial. Presently, there are no prospective clinical trials that define the optimal therapy for posttransplantation bone disease. Combined pharmacologic therapy that targets multiple components of the disordered pathways has been used. Although bisphosphonate or calcitriol therapy can preserve bone mineral density after transplantation, there is no evidence that these agents decrease fracture risk. Moreover, bisphosphonates pose potential risks for adynamic bone disease.

Total Parathyroidectomy versus Subtotal Parathyroidectomy in the Treatment of Tertiary Hyperparathyroidism

The purposes of this study are to evaluate the merits of surgical treatment, including subtotal parathyroidectomy (SP) and total parathyroidectomy (TP), in patients with tertiary hyperparathyroidism (THPT) and compare the outcome of the two surgical options. Medical records of patients undergoing parathyroidectomy for THPT were retrospectively reviewed and long-term outcomes between the two groups were compared. Fourteen out of 488 renal transplantation recipients required parathyroidectomy for THPT during a 24-year follow-up period with a median follow-up of 35.5 [interquartile range (IQR), 19.3–133.3] months. All patients had hypercalcemia, whereas 13 had varying symptoms and one was asymptomatic. Median serum calcium level decreased from 12.4 (IQR, 11.9–12.6) mg/dL preoperatively to 8.9 (IQR, 8.1–9.4) mg/dL postoperatively ( P = 0.001), whereas median intact parathyroid hormone (iPTH) dropped from a preoperative level of 340.5 (IQR, 247–540) pg/mL to 55.1 (IQR, 24.4–66.4) pg/mL after surgery ( P = 0.018). Comparison between patients receiving TP and SP revealed no difference in incidence of recurrence or permanent complications, whereas the former had significantly lower calcium levels ( P = 0.048) and higher phosphorus levels ( P = 0.017) compared with the latter. Moreover, a significant reduction in calcium level was noted in TP group on long-term follow-up compared with their immediately postoperative level (8.1 vs 9.0 mg/dL, respectively, P < 0.05), whereas there was no significant decrease in SP group. We concluded that parathyroidectomy is efficient and safe in treating THPT. Because TP would increase the risk of hypocalcemia, a less radical procedure (SP) is preferred.

Frequency of ectopic and supernumerary intrathymic parathyroid glands in patients with renal hyperparathyroidism: analysis of 461 patients undergoing initial parathyroidectomy with bilateral cervical thymectomy

BACKGROUND

The frequency of intrathymic parathyroid glands (IPGs) in patients undergoing parathyroidectomy for renal hyperparathyroidism (rHPT) varies considerably between 14.8% and 45.3%. Total parathyroidectomy with autotransplantation and subtotal parathyroidectomy are the most accepted surgical procedures to treat patients with rHPT. However, routine bilateral cervical thymectomy (BCT) is still discussed, although controversially.

METHODS

From a prospective database of patients who underwent parathyroid surgery for rHPT between 1975 and 2009, patients with routine BCT at initial PTX were further analyzed regarding the frequency of ectopic and supernumerary IPGs. Duration of hemodialysis and stage of chronic kidney disease were correlated with the frequency of supernumerary IPGs to elucidate a potential role of long-standing proliferation stimuli to any surplus parathyroid tissue.

RESULTS

Initial parathyroidectomy with BCT was performed in 461 patients. IPGs were resected in 205 of them (44.5%). They were ectopic in 181 (39.3%) and supernumerary in 30 patients (6.5%). The frequency of supernumerary IPGs in patients on permanent hemodialysis was 7.4% (29/392), 3.9% (1/26) in predialysis patients, and 0% (0/43) in patients after successful kidney transplantation. This differences reached no statistical significance.

CONCLUSIONS

BCT is essential in patients with fewer than four parathyroid glands identified at typical positions. Because of the low frequency of supernumerary IPGs and a suspected low proliferation stimulus, the relevance of BCT after resection of four glands in predialysis patients and those after successful kidney transplantation must be questioned. Nevertheless, routine BCT seems to be acceptable and can be recommended in patients on permanent hemodialysis not awaiting kidney transplantation until proven otherwise by prospective trials.

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.

Calcific uremic arteriolopathy: pathophysiology, reactive oxygen species and therapeutic approaches

Calcific uremic arteriolopathy (CUA)/calciphylaxis is an important cause of morbidity and mortality in patients with chronic kidney disease requiring renal replacement. Once thought to be rare, it is being increasingly recognized and reported on a global scale. The uremic milieu predisposes to multiple metabolic toxicities including increased levels of reactive oxygen species and inflammation. Increased oxidative stress and inflammation promote this arteriolopathy by adversely affecting endothelial function resulting in a prothrombotic milieu and significant remodeling effects on vascular smooth muscle cells. These arteriolar pathological effects include intimal hyperplasia, inflammation, endovascular fibrosis and vascular smooth muscle cell apoptosis and differentiation into bone forming osteoblast-like cells resulting in medial calcification. Systemic factors promoting this vascular condition include elevated calcium, parathyroid hormone and hyperphosphatemia with consequent increases in the calcium × phosphate product. The uremic milieu contributes to a marked increased in upstream reactive oxygen species—oxidative stress and subsequent downstream increased inflammation, in part, via activation of the nuclear transcription factor NFκB and associated downstream cytokine pathways. Consitutive anti-calcification proteins such as Fetuin-A and matrix GLA proteins and their signaling pathways may be decreased, which further contributes to medial vascular calcification. The resulting clinical entity is painful, debilitating and contributes to the excess morbidity and mortality associated with chronic kidney disease and end stage renal disease. These same histopathologic conditions also occur in patients without uremia and therefore, the term calcific obliterative arteriolopathy could be utilized in these conditions.

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.

Calcific Uremic Arteriolopathy: Pathophysiology, Reactive Oxygen Species and Therapeutic Approaches

Calcific uremic arteriolopathy (CUA)/calciphylaxis is an important cause of morbidity and mortality in patients with chronic kidney disease requiring renal replacement. Once thought to be rare, it is being increasingly recognized and reported on a global scale. The uremic milieu predisposes to multiple metabolic toxicities including increased levels of reactive oxygen species and inflammation. Increased oxidative stress and inflammation promote this arteriolopathy by adversely affecting endothelial function resulting in a prothrombotic milieu and significant remodeling effects on vascular smooth muscle cells. These arteriolar pathological effects include intimal hyperplasia, inflammation, endovascular fibrosis and vascular smooth muscle cell apoptosis and differentiation into bone forming osteoblast-like cells resulting in medial calcification. Systemic factors promoting this vascular condition include elevated calcium, parathyroid hormone and hyperphosphatemia with consequent increases in the calcium × phosphate product. The uremic milieu contributes to a marked increased in upstream reactive oxygen species—oxidative stress and subsequent downstream increased inflammation, in part, via activation of the nuclear transcription factor NFκB and associated downstream cytokine pathways. Consitutive anti-calcification proteins such as Fetuin-A and matrix GLA proteins and their signaling pathways may be decreased, which further contributes to medial vascular calcification. The resulting clinical entity is painful, debilitating and contributes to the excess morbidity and mortality associated with chronic kidney disease and end stage renal disease. These same histopathologic conditions also occur in patients without uremia and therefore, the term calcific obliterative arteriolopathy could be utilized in these conditions.