Renal transplant nephrectomy in children: can an aggressive approach be recommended?

Pearls and Pitfalls in Pediatric Kidney Transplantation After 5 Decades

Worldwide, over 1,300 pediatric kidney transplantations are performed every year. Since the first transplantation in 1959, healthcare has evolved dramatically. Pre-emptive transplantations with grafts from living donors have become more common. Despite a subsequent improvement in graft survival, there are still challenges to face. This study attempts to summarize how our understanding of pediatric kidney transplantation has developed and improved since its beginnings, whilst also highlighting those areas where future research should concentrate in order to help resolve as yet unanswered questions. Existing literature was compared to our own data of 411 single-center pediatric kidney transplantations between 1968 and 2020, in order to find discrepancies and allow identification of future challenges. Important issues for future care are innovations in immunosuppressive medication, improving medication adherence, careful donor selection with regard to characteristics of both donor and recipient, improvement of surgical techniques and increased attention for lower urinary tract dysfunction and voiding behavior in all patients.

Management of the Failing Kidney Transplant: Challenges and Solutions

The kidneys are the most transplanted organs, and the number of failed kidney transplants that require reinstitution of renal replacement therapy in patients is on the increase. Increased mortality has been noted in patients with failed grafts compared with transplant- naïve patients with chronic kidney disease who are treated with dialysis. Issues such as management of immunosuppression, the need for transplant nephrectomy, addressing the increased risk of cardiovascular events, malignancies, and infections are debatable and often based on individual or hospital practices. The optimal timing and modality of renal replacement therapy to be reinitiated are sometimes blurred, with considerable variations among physician practices. Guidelines are therefore needed to appropriately manage this special population of patients with the aim of improving outcomes. Here, our objective was to review the current practices in managing patients with failing kidney transplants so that recommendations can be made based on the available evidence.

Practice patterns and influence of allograft nephrectomy in pediatric kidney re-transplantation: A pediatric nephrology research consortium study

INTRODUCTION

There are no guidelines regarding management of failed pediatric renal transplants.

MATERIALS & METHODS

We performed a first of its kind multicenter study assessing prevalence of transplant nephrectomy, patient characteristics, and outcomes in pediatric renal transplant recipients with graft failure from January 1, 2006, to December 31, 2016.

RESULTS

Fourteen centers contributed data on 186 pediatric recipients with failed transplants. The 76 recipients that underwent transplant nephrectomy were not significantly different from the 110 without nephrectomy in donor or recipient demographics. Fifty-three percent of graft nephrectomies were within a year of transplant. Graft tenderness prompted transplant nephrectomy in 91% (P < .001). Patients that underwent nephrectomy were more likely to have a prior diagnosis of rejection within 3 months (43% vs 29%; P = .04). Nephrectomy of allografts did not affect time to re-listing, donor source at re-transplant but significantly decreased time to (P = .009) and incidence (P = .0002) of complete cessation of immunosuppression post-graft failure. Following transplant nephrectomy, recipients were significantly more likely to have rejection after re-transplant (18% vs 7%; P = .03) and multiple rejections in first year after re-transplant (7% vs 1%; P = .03).

CONCLUSIONS

Practices pertaining to failed renal allografts are inconsistent-40% of failed pediatric renal allografts underwent nephrectomy. Graft tenderness frequently prompted transplant nephrectomy. There is no apparent benefit to graft nephrectomy related to sensitization; but timing / frequency of immunosuppression withdrawal is significantly different with slightly increased risk for rejection following re-transplant.

Graft nephrectomy in children

Kidney transplantation is recognised as the gold standard treatment of end-stage renal disease in most children, with excellent graft survival rates. When graft failure occurs, renal transplant recipients (RTRs) have the option of removal of the transplant (graft nephrectomy [GN]), or leaving the failed transplant in situ. The aims of this review are to discuss the indications for GN, surgical techniques, outcomes after GN (including risks of allosensitisation and the impact on subsequent transplants), and the possible role of routine GN in the asymptomatic RTR with a failed renal allograft. Literature in both the pediatric and adult renal transplant fields is reviewed. We also discuss how future research in this area could advance our knowledge of which patients to select for GN, and the most appropriate surgical approach.

Transplant nephrectomy: histologic findings—a single center study

AIMS

To identify the histopathological features of transplant nephrectomy (TN) specimens.

METHODS

We performed retrospective analysis of 73 nephrectomies to review the histopathology in detail and correlate the Banff grading characteristics of TN specimens with time post engraftment and clinical features. Retrospective data on donor-specific antibodies (DSA) were also collected.

RESULTS

The majority of patients who had TN in less than 3 months posttransplant (n = 20; median time to TN: 4 days) had hemorrhagic infarction; 7 patients (35%) had grade 3 acute rejection (AR). Patients who had TN later than 3 months posttransplant (n = 53; median time to TN: 67 months) had AR, grade 2B (21%) and 3 (43%), coexisting with advanced vascular injury in the form of interstitial hemorrhage, extensive interstitial fibrosis and tubular atrophy (IF/TA) as well as the presence of DSAs. Overall, the majority of patients without DSA pre-TN developed DSA post-TN.

CONCLUSIONS

Our data revealed extensive inflammation and ongoing immunologic activity in a subset of patients with a failed graft. Careful and individualized approach based on clinical and laboratory data should guide the decision for transplant nephrectomy.

Transplant nephrectomy

About 10% of all renal allografts fail during the first year of transplantation and thereafter approximately 3%-5% yearly. Given that approximately 69 400 renal transplants are performed worldwide annually, the number of patients returning to dialysis following allograft failure is increasing. A failed transplant kidney, whether maintained by low dose immunosuppression or not, elicits an inflammatory response and is associated with increased morbidity and mortality. The risk for transplant nephrectomy (TN) is increased in patients who experienced multiple acute rejections prior to graft failure, develop chronic graft intolerance, sepsis, vascular complications and early graft failure. TN for late graft failure is associated with greater morbidity and mortality, bleeding being the leading cause of morbidity and infection the main cause of mortality. TN appears to be beneficial for survival on dialysis but detrimental to the outcome of subsequent transplantation by virtue of increased level of antibodies to mismatched antigens, increased rate of primary non function and delayed graft function. Many of the studies are characterized by a retrospective and univariate analysis of small numbers of patients. The lack of randomization in many studies introduced a selection bias and conclusions drawn from such studies should be applied with caution. Pending a randomised controlled trial on the role of TN in the management of transplant failure patients, it is prudent to remove failed symptomatic allografts and all grafts failing within 3 mo of transplantation, monitor inflammatory markers in patients with retained failed allografts and remove the allograft in the event of a significant increase in levels.

Hyperthermia alters kidney function and renal scintigraphy

BACKGROUND/AIM

Fever can be caused by different reasons such as environmental conditions, acute rejection after kidney transplantation and bacterial diseases including kidney and urinary tract infections. The present study represents a novel idea of investigating the direct effect of body temperature elevation on kidney function to determine whether hyperthermia alters the kidney function transiently leading to inaccurate findings and possible misinterpretation of the radionuclide (99mTc-MAG-3) renography studies.

METHODS

Renography studies were performed on New Zealand White rabbits weighing approximately 3-3.5 kg. Each rabbit was inject with 48.1 MBq (1.3 mCi) technetium-99m-mercaptoacetyltriglycine (99mTc-MAG-3). Studies were acquired using a gamma camera equipped with a low-energy, high-resolution collimator interfaced with a computer. Dynamic images were acquired as 2-s frames for the first 1 min and every 30 s for the next 30 min on a matrix of 64 x 64. Regions of interest were drawn over the whole kidneys. Radioactivity time curves were generated from the regions of interest. Time to peak activity (Tmax), time from peak to 50% activity (T1/2), and the uptake slope of each kidney were calculated from the renograms. Three days later the same protocol was repeated for the same rabbit but with a higher body temperature by 2 degrees C. Then it was repeated with a higher body temperature by 3 degrees C, then 4 degrees C with the same interval period. Blood pressure was measured using a catheter inserted into the femoral artery connected to a Lectromid recorder at normal temperature and during increasing the temperature by 2, 3 and 4 degrees C. Renal blood flow was also measured via the renal artery using an electromagnetic blood flow sensor connected to a flowmeter. Creatinine and blood urea nitrogen (BUN) in blood were measured in control and hyperthermic rabbits.

RESULTS

During hyperthermia the experimental curves shifted to the right of the control curves indicating that there was a delayed renal uptake of 99mTc-MAG-3 and clearance of radioactivity. This delay was proportional to body temperature. Calculated averages were: Tmax 1.6 +/- 0.1, 2.8 +/- 0.3, 8.8 +/- 1, 15 +/- 4 min; T1/2 2.77 +/- 0.2, 3 +/- 0.4, 8.9 +/- 1.1, 20 +/- 3.4 min, and perfusion index 190 +/- 5, 201 +/- 4, 218 +/- 7, 224 +/- 9 of control and hyperthermic (elevation of temperature 2, 3, and 4 degrees C) rabbits, respectively (n = 6; p < 0.05). Mean arterial pressure and renal blood flow did not significantly change during hyperthermia. Creatinine and BUN were proportionally elevated to high temperature.

CONCLUSIONS

Our results indicate that hyperthermia causes a transient alteration in the function of the kidney and scintigraphic pattern on radionuclide renography. Radionuclide renography studies may be performed at normothermic temperature since interpretation at higher body temperature could lead to misleading results, and temperature should be checked and recorded for single and follow-up radionuclide renography studies.

Interventional stenting for ruptured iliac aneurysm following transplant nephrectomy

Surgical removal of a failed kidney graft may lead to a variety of postoperative complications, development of an aneurysm being a relatively rare complication. We report the case of a 34-year-old man who developed an iliac aneurysm 13 years after transplant nephrectomy. Interventional stenting was performed upon the rupture of the aneurysm. Postintervention the function of the contralateral transplanted kidney was stable and the patient recovered. An endoleak was diagnosed after 1 week, which was also stented. No operative procedure was necessary. In conclusion, even in an emergency situation interventional stenting of a false iliac aneurysm after transplant nephrectomy may be a therapeutic option.