Pediatric en bloc kidney transplantation into pediatric recipients

Pediatric en bloc kidney transplant from donors <15 kg: An excellent approach to expand the pediatric deceased donor pool

INTRODUCTION

Most kidneys from small pediatric donors are transplanted to adult recipients because of the perceived risk of surgical complications and graft thrombosis. In this study, we aim to demonstrate our favorable outcomes in transplanting pediatric kidneys from donors <15 k into pediatric recipients.

METHODS

This study retrospectively analyzes the outcomes of seven pediatric recipients of en block kidney transplants from pediatric donors weighing <15 kg performed at King Fahad Specialist Hospital-Dammam from December 2014 to January 2018. Baseline characteristics of donors and recipients were collected. The incidences of surgical complication, immediate, and intermediate graft function were the primary outcomes.

RESULTS

The study included seven recipients monitored for a mean duration of 6.86 ± 1.35. Donors' and recipients' mean weights were 7.4 ± 3.2 kg and 20.7 ± 9.2 kg, respectively. Ureteric stricture occurred in one patient. There was a substantial improvement of 1-year estimated glomerular filtration rate (eGFR) compared to the 1-week mark (106.7 ± 26.38 mL/min. 1.73 m2 vs. 63.7 ± 22.92 mL/min/1.73 m2, p = .0069). The observed improvement in renal function persisted at the 5-year mark and during the last follow-up, with eGFR of 70.3 ± 40.7 mL/min/1.73 m2, and 79.8 ± 30.8 mL/min/1.73 m2, respectively. There was also increase of 27.9% in the size of the en bloc kidney observed at the 6 months.

CONCLUSION

In a specialized transplant center with highly skilled surgeons, the utilization of en bloc kidney transplant from donors weighing less than 15 kg is an effective strategy for expanding the donor pool and ensuring favorable graft outcomes.

Surgical complications in pediatric kidney transplantation-Incidence, risk factors, and effects on graft survival: A retrospective single-center study

The field of pediatric kidney transplantation remains challenging due to an ongoing lack of size-matched grafts and anatomical peculiarities. In the current study, we investigated the incidence of surgical complications in pediatric recipients, with a focus on risk factors and effects on graft outcome. We retrospectively reviewed all 2386 kidney transplantations at our institution from January 2005 until December 2018. Of these, 221 transplants were performed in pediatric recipients, defined as under the age of 18 years. Donor-recipient body surface area ratios were calculated to evaluate the effects of size mismatching. Regression analyses were performed to identify independent risk factors for surgical complications and graft survival, respectively. Perioperative surgical complications requiring revision were observed in 34 (15.4%) cases. Leading cause for revision were vascular complications such as thrombosis or stenosis (n = 15 [6.8%]), which were significantly more frequent in case of young donors, (ie, donor age <6 years; OR: 4.281; CI-95%:1.385-13.226; P = .012), previous nephrectomy (OR: 3.407; CI-95%:1.019-11.387; P = .046), and en-bloc grafts (OR: 4.923; CI-95%:1.355-17.884; P = .015), followed by postoperative hemorrhage (n = 10 [4.5%]), ureteral complications (n = 8 [3.6%]), and lymphoceles (n = 7 [3.2%]). Median follow-up was 84.13 (0.92-175.72) months. One-, 5-, and 10-year graft survival rates were 97.1%, 88.9%, and 65.1%, respectively. Except for vascular complications (HR: 4.727; CI-95%:1.363-16.394; P = .014), none of the analyzed surgical morbidities significantly influenced graft survival. In conclusion, pediatric kidney transplantation achieves excellent long-term results. However, meticulous surgical technique and continuous postoperative monitoring are imperative for early detection and treatment of imminent vascular complications, especially in case of young donors and en-bloc grafts.

Single versus en bloc kidney transplant from donors less than or equal to 15 kg to pediatric recipients

With small kidneys, EBKTs could provide sufficient renal mass but could lead to inefficient use of resources, while SKTs could result in insufficient function due to small renal mass. We aimed to compare the outcomes of EBKT and SKT from small donors weighing ≤15 kg to pediatric recipients. We retrospectively reviewed all pediatric patients who met the inclusion criteria between January 1, 1984, and April 30, 2019, at a single institution. Of a total of 23 patients, 12 received EBKT and 11 received SKT. The median age of donors, weight of donors, and weight of recipients were comparable between the two groups. The median age of recipients and median weight of allografts were greater in the EBKT group than in the SKT group. The median follow-up was 53.9 months. There was no significant difference in eGFR, protein creatinine ratios at 1-year follow-up, and overall graft survival. The size of the kidney increased by approximately 13%-43% in the EBKT group and 40%-60% in the SKT group. This study demonstrated that kidneys from small donors weighing 5-15 kg could be split in pediatric recipients without compromising the outcome.

A novel technique for en bloc kidney transplantation from infant donors with extremely low body weight by using the distal abdominal aorta as an outflow tract

Pediatric kidney donors remain underutilized due to the high risk of postoperative thrombosis. To address this problem, we developed a novel en bloc kidney transplantation technique using donor thoracic aorta and the distal abdominal aorta as inflow and outflow tracts, respectively. Briefly, eight kidneys from deceased infant donors under five months old and with low body weight (1.9-4.9 kg) were transplanted en bloc into four pediatric and four adult patients. The donor's common iliac artery or external iliac artery was anastomosed to the recipient's distal external iliac artery or inferior epigastric artery, respectively, as an outflow tract. Recipients received basiliximab or antithymocyte globulin as induction therapy followed by tacrolimus, mycophenolate mofetil, and prednisone but without prophylactic anticoagulation. Delayed graft function was observed in one patient but was reversed at 90 days posttransplant. Two patients had urine leakage, which was cured by conservative treatment. Two recipients developed lung infections that eventually cleared. No patients experienced posttransplant vascular thrombosis. After 1-1.5 years of follow-up, all patients are well and have normal serum creatinine levels. In conclusion, this novel en bloc kidney transplantation technique using a modified arterial inflow and outflow tract can prevent vascular thrombosis and provide adequate graft function.

Successful Repair of Bilateral Ureteral Stricture 3 Years after En Bloc Kidney Transplant: A Case Report

En bloc kidney transplants of small pediatric kidneys into adult recipients have been shown to have outcomes similar to transplants from standard adult deceased donors. Here, we report a 27-year-old male patient with successful repair of bilateral ureteral stricture 3 years after en bloc kidney transplant at the Shahid Modarres Hospital (Tehran, Iran). The patient received an en bloc deceased kidney donation from a 9-month-old infant. An end-to-end anastomosis of the aorta to the internal iliac artery and an end-to-side external iliac vein anastomosis to vena cava were performed. At an outpatient visit about 2.5 years later, the patient showed increasing levels of creatinine from 1.1 to 1.8 mg/dL compared with measurements at his 2-month visit. A computed tomography scan performed without any contrast agent at that time confirmed the existence of hydronephrosis in both the medial and lateral kidneys. A nephrostography showed a ureteral stricture. Because endoscopic surgery for ureteral dilatation was not successful, the decision was made to perform ureteral repair by the open surgical technique. The short length of the ureters resulted in the lateral renal pelvis being anastomosed to the bladder by flap (Boari flap). The ureter of the patient's native kidney was transected in the middle portion, and the distal ureter was anastomosed to the medial renal pelvis using the end-to-end method. Here, we showed that, despite limited experiences with pediatric donors, en bloc kidney transplant can be performed under the guidance of experienced surgical techniques and precise postoperative follow-up.

En bloc kidney transplantation from infant donors younger than 10 months into pediatric recipients

Early graft loss and poor graft function limit the use of kidneys from infant donors. Six en bloc kidney transplantations were performed from infant donors younger than 10 months into pediatric recipients between November 2012 and September 2015 at our center. We retrospectively analyzed recipient and donor demographics, surgery procedures, complications, graft function and size, and patient and graft survival with a follow-up of 6-39 months (median 15.5 months). Donor age ranged from 1 to 10 months with weight ranging from 3.5 to 10 kg. Recipient age ranged from 10 to 16 years with weight ranging from 30 to 39 kg. One kidney was removed due to arterial thrombosis during surgery, while the other kidney of this en bloc graft remained viable. Urine leak followed by bilateral ureteral obstruction occurred in one recipient. All of the recipients showed immediate graft function. The size of the en bloc kidney increased from 4.2±0.6 cm to 7.6±0.6 cm 6 months after surgery. Patient and graft survival were both 100% at the last follow-up. Our results show that en bloc kidney transplantation from infant donors younger than 10 months into pediatric recipients is effective under the condition of experienced surgical techniques and perioperative management.

En Bloc Cadaver Kidney Transplantation From a 9-Month-Old Donor to an Adult Recipient: Maturation of Glomerular Size and Podocyte in the Recipient

BACKGROUND

Favorable outcomes of en bloc pediatric donor kidney transplantation to adult recipients are attributed primarily to grafting of twice the nephron mass of a single kidney.

METHODS

The kidneys of a 9-month-old male infant were transplanted en bloc in a 56-year-old man. Biopsies were performed 1 hour postreperfusion, 6 months and 3.5 years posttransplant.

RESULTS

Warm and cold ischemia times were 21 and 426 minutes, respectively. The recipient was released from hemodialysis 10 days posttransplant and discharged 91 days posttransplant when serum creatinine was 0.9 mg/dL. At 4 years and 9 months posttransplant, serum creatinine was 1.0 mg/dL, and estimated glomerular filtration rate was 58.0 mL/min per 1.73 m². The grafts increased in size until they reached adult size by 3 months posttransplant. The glomerular area and volume, respectively, increased from 5.9 × 10³ μm² and 0.34 × 10⁶ μm³ at 1 hour postreperfusion to 14.9 × 10³ μm² and 1.27 × 10⁶ μm³ at 3.5 years posttransplant, both of which were less than half of adult size. At 1 hour postreperfusion, podocytes were structurally immature. At 6 months posttransplant, podocyte immaturity was still evident. At 3.5 years posttransplant, podocytes were mature.

CONCLUSIONS

These findings suggest that podocytes and glomerular size of pediatric donor kidneys can continue to mature in adult recipients at rates appropriate for donor age when transplanted en bloc. The maturational levels of podocytes and glomeruli may also be a factor involved in favorable outcomes of en bloc pediatric donor kidney transplantation.

Comparable Survival of En Bloc versus Standard Donor Kidney Transplants in Children

OBJECTIVE

To determine whether renal transplantation survival is similar in children receiving pediatric en bloc kidneys compared with those receiving standard deceased donor kidneys.

STUDY DESIGN

We compared time to allograft failure and estimated glomerular filtration rate (eGFR) in pediatric recipients of en bloc and standard criteria deceased donor renal transplants using Organ Procurement and Transplantation Network data for 2000-2013. Cox regression analysis was used to compare time to allograft failure, and the Student t test was used to compare eGFR.

RESULTS

A total of 6882 recipients met the study inclusion criteria; 1.8% received an en bloc transplant. The adjusted hazard for allograft failure was similar for recipients of en bloc kidneys compared with standard criteria kidneys (hazard ratio, 1.15; 95% CI, 0.83-1.59; P = .41). The median wait time for transplantation was significantly shorter for recipients of en bloc kidneys (157 days vs 208 days; P = .03). Moreover, eGFR was superior for recipients of en bloc kidneys up to 5 years post-transplantation.

CONCLUSION

Transplantation of en bloc pediatric kidneys should be considered a viable option for pediatric recipients and may afford unique benefits by reducing wait times and promoting preservation of graft function.

Optimizing the utilization of kidneys from small pediatric deceased donors under 15 kg by choosing pediatric recipients

Currently, most kidneys from small pediatric deceased donors are transplanted into adult recipients (i.e., PTA). However, due to the weight mismatch, there is a high discard rate and a high ratio of EBKTs if adopting PTA. Here, we sought both to optimize utilization of these challenging but scarce donor grafts by selecting pediatric recipients and to characterize the feasibility and efficacy of this PTP allocation strategy. From February 2012 to October 2014, kidneys from 27 infant donors ≤ 15 kg were procured and distributed to 38 pediatric candidates in our center. The grafts were utilized for EBKT if the donor weighed 2.5-5 kg and for SKT if the donor weighed 5-15 kg, leading to 10 EBKTs and 28 SKTs. The overall utilization rate from small pediatric deceased donors was 94.12%. After a follow-up of 3-26 months, the graft survival rate was 89.47%, with four graft losses due to vascular thrombosis. Kidneys from low-body-weight donors should be applied to pediatric recipients, and the kidneys from infant donors ≥ 5 kg can be used in single-kidney-transplant procedures at experienced centers to optimize utilization.

Renal Transplantation From Pediatric Donors in the United Kingdom

BACKGROUND

Significant disparity exists in the United Kingdom between the need for organ transplant and supply of deceased donor organs. In the recent years, efforts to increase donation has improved the rate of mainly deceased donors after circulatory death and from older donors. The rate of donation from pediatric population has remained low and those younger than 2 years including neonatal donation has remained largely unexplored.

METHODS

A retrospective review of the outcome of renal transplantation from pediatric donor (<18 years) kidneys in the United Kingdom.

RESULTS

Our results show a poor referral and conversion rate, and high discard rate (43%) of kidneys procured from donors younger than 2 years. During the 15-year study period (1997-2011), 47 donors younger than 2 years were referred (3 per year). Of these, 26 proceeded to donation resulting in 17 transplants (65% utilization). The referral rate for donors 2 years or older to younger than 5 years also remains low (76 in 15 years), but the conversion (88%) and utilization rates (73%) are better in this group. There was better utilization in donors aged 5 years or older to younger than 18 years. Overall graft and patient survival remains excellent in all 3 groups; with comparable survival of 82%, 85%, and 77% (P = 0.29) with mean follow-up periods of 9, 12.5, and 11.8 years, respectively.

CONCLUSIONS

Despite excellent outcome, the referral, donation, and utilization of kidneys from donors younger than 5 years and particularly those younger than 2 years remain low. We suggest implementing improved strategies to increase donation from this group of population.

Pediatric Organ Donation Potential at a Children's Hospital

OBJECTIVES

To estimate the organ donation potential of patients dying at a children's hospital.

DESIGN

Retrospective cohort study.

SETTING

A free-standing, 271-bed, tertiary Children's Hospital with a pediatric trauma center.

PATIENTS

Patients dying in any ICU during 2011-2012.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 224 deaths, 23 (10%) met neurologic criteria for death: 18 donated organs (conversion rate 78%), 47 (19%) died without prior limitation of life-sustaining therapies, and the remaining 69% had withdrawal of life-sustaining therapies. Among those dying after withdrawal of life-sustaining therapies (n = 154), the organ procurement organization was not notified prior to death in 24%, and older patients were more likely to be referred compared to those less than 1 year old. Infection, cancer, and organ dysfunction were the most frequent conditions that disqualified dying patients from suitability for donation. Just over half of children more than 1 year old were suitable for donation after withdrawal of life-sustaining therapies compared to a fifth of infants (19%). Of 45 suitable for donation, 37 (82%) died within 1 hour. None of 7 infants younger than 1 month old died within 20 minutes, compared with 46% of infants between 1 month and 1 year (n = 6) and 72% of older children. Thirty-three families (73%) did not permit donation after circulatory criteria for death whereas 12 (27%) gave permission for donation, and all 12 were actual donors (conversion rate 12/37 [32%]).

CONCLUSIONS

The number of pediatric potential candidates for donation after circulatory determination of death was significantly larger than potential candidates for donation after neurologic determination of death at our hospital, but the actual donation rate was significantly lower. Increasing acceptance of donation after circulatory determination of death could increase organ donation. Among all children having withdrawal of life-sustaining therapies, donation after circulatory determination of death potential is less for infants.

Recent developments in kidney transplantation in children

PURPOSE OF REVIEW

Renal transplantation in childhood is a well established procedure with excellent short-term outcomes. However, waiting times for transplantation are still relatively long if living donation cannot be performed, and long-term outcomes after transplantation have not significantly improved during the last decade.

RECENT FINDINGS

This review describes alternative modalities to improve donation rates such as en bloc kidney transplantation from young donors, ABO-incompatible transplantation and kidney paired donation. This review also deals with long-term post-transplant morbidities, such as follows: first, medication side-effects (metabolic syndrome, cardiovascular disease) and with the benefits of steroid and calcineurin inhibitor drug minimization; second, the deleterious impact of viral infections and their management and third, chronic antibody-mediated rejection, its therapeutic and prevention possibilities.

SUMMARY

Donor shortage and long-term morbidities, after transplantation, are still relevant issues in paediatric renal transplantation medicine. Significant research and efforts have been made to advance the field and create novel approaches for improvement of transplantation rates and post-transplant graft or patient survival. These modalities are to be established in the routine setting.

En bloc kidneys transplanted from infant donors less than 5 kg into pediatric recipients

BACKGROUND

Given the shortage of donor kidneys, the use of grafts from deceased infant donors is a potential approach to expand the donor pool. Four infant en bloc kidney transplants in pediatric recipients were reported, performed between 2012 and 2013 in the center.

METHODS

The en bloc graft was implanted extraperitoneally in the right iliac fossa. The distal end of the donor aorta was anastomosed end-to-end to the internal iliac artery, while the donor vena cava was anastomosed (end-to-side) to the external iliac vein. Both ureters were anastomosed individually to the bladder, with the exception of one case in which a donor bladder patch was anastomosed to the bladder. After the operation, the recipients received basiliximab as induction therapy followed by tacrolimus and mycophenolic acid for immunosuppression. Prophylactic anticoagulation was used postoperatively.

RESULTS

Recipients included two girls and two boys with age ranging from 4.6 to 11.6 years. Donor age ranged from 33 to 56 days with weight ranging from 2.5 to 5.0 kg. After a follow-up of 2 to 14 months, patient and graft survivals were 100% and 75%, respectively. Complications included delayed graft function in one patient, urine leak in one, and anticoagulation-related hemorrhage in one. One graft was lost early from vascular thrombosis. The remaining three recipients had excellent graft function with median serum creatinine of 1.1 mg/dL (range, 0.8-1.3 mg/dL) at last follow-up.

CONCLUSIONS

Promising outcomes can be obtained from en bloc transplantation from infant donors. The use of this donor population for pediatric recipients should be encouraged.

Identifying potential kidney donors among newborns undergoing circulatory determination of death

BACKGROUND

Over 96,000 patients await kidney transplantation in the United States, and 35,000 more are wait-listed annually. The demand for donor kidneys far outweighs supply, resulting in significant waiting list morbidity and mortality. We sought to identify potential kidney donors among newborns because en bloc kidney transplantation donation after circulatory determination of death (DCDD) may broaden the donor pool.

METHODS

We reviewed discharges from our 84-bed NICU between November 2002 and October 2012 and identified all deaths. The mode of death among potential organ donors (weight ≥ 1.8 kg) was recorded. Patients undergoing withdrawal of life support were further evaluated for DCDD potential. After excluding patients with medical contraindications, those with warm ischemic time (WIT) less than 120 minutes were characterized as potential kidney donors.

RESULTS

There were 11,201 discharges. Of 609 deaths, 359 patients weighed ≥ 1.8 kg and 159 died after planned withdrawal of life support. The exact time of withdrawal could not be determined for 2 patients, and 100 had at least 1 exclusion criterion. Of the remaining patients, 42 to 57 infants were potential en bloc kidney donors depending on acceptance threshold for WIT. Applying a 40% to 70% consent rate range would yield 1.7 to 4 newborn DCDD donors per year.

CONCLUSIONS

A neonatal DCDD kidney program at our institution could provide 2 to 4 paired kidneys for en bloc transplantation each year. Implementing a DCDD kidney donation program in NICUs could add a new source of donors and increase the number of kidneys available for transplantation.

Kidney grafts from donors ≤ 5 yr of age: single kidney transplantation for pediatric recipients or en bloc transplantation for adults?

Kidneys from donors ≤5 yr of age represent a controversial issue. The purpose of this study was to compare the transplant outcomes as single and single/en bloc grafts into pediatric and adult KT recipients, respectively. All recipients of kidneys from donors ≤5 yr old transplanted at our institution from 3/2003 to 12/2010 were evaluated, and corresponding data were analyzed. There were 11 pediatric and 14 adult recipients. Median donor age and body weight were 38 months and 14 kg, respectively. PNF, n = 2 and DGF, n = 1 were observed only among adult recipients. Five-yr graft survival was 100% for children and 86% for adults. There were no significant differences in graft and patient survival, PNF, DGF, acute rejection, or postoperative complications among children/single (n = 10), adults/en bloc (n = 10), and adults/single (n = 4) KT. Major complications were documented in six adult recipients and one pediatric recipient after en bloc KT. Pediatric recipients showed significantly higher GFR during the first post-transplant year. Kidneys from donors ≤5 yr of age have at least as good outcomes as when transplanted as single allografts into children. Although the study-volume is small, it seems that children benefit from a pediatric-oriented allocation policy.

Outcomes of children receiving en bloc renal transplants from small pediatric donors

The utilization of en bloc renal allografts from small pediatric donors has been adopted as an effective strategy to expand the organ donor pool in adult recipients. Data in children are limited. The aim of our study is to describe the outcomes of en bloc renal transplants in children from our center. Medical records of children receiving pediatric en bloc renal transplants at our institution from January 2007 were abstracted. Data collected included recipient and donor demographics, operative technique and complications, and post-operative studies. Eight children received en bloc renal transplants at a median age of 17 yr; median follow-up was 0.9 yr. Donor body weight ranged from 4 to 22 kg. One kidney was lost to intra-operative thrombosis, while the other kidney from this en bloc graft remained viable. All grafts showed increased renal size at follow-up ultrasound. Surveillance biopsies showed glomerulomegaly in two patients. At last follow-up, the median eGFR was 130 mL/min/1.73 m(2). The urinary protein to creatinine ratio was normal in four of seven patients. Our data suggest that in experienced centers, en bloc renal transplantation from young donors into pediatric recipients is effective. Long-term follow-up to monitor for complications, including hyperfiltration injury, is warranted.

Pediatric en bloc kidney transplantation into pediatric recipients: the French experience

Chronic shortage of available donor organs has led to re-evaluation of the use of en bloc kidney transplants. Although excellent results have been reported in adult patients, experience in pediatric patients remains limited because of potential early complications and poor long-term graft outcome. We report 14 pediatric en bloc renal transplantations into 14 pediatric recipients, performed between 1990 and 2007 in France. We retrospectively analyzed demographic data, postoperative complications, and graft function with a median follow-up of five yr. Donor age ranged from four to 54 months. Complications were vascular graft thrombosis in four patients, leading to graft loss in two cases, and to excellent long-term graft function in the two others. Two hemorrhagic complications resulted in death in one case and in graft loss in the other. Six acute rejection episodes occurred in four patients. Median glomerular filtration rate at three months, one, five, and 10 yr was 90.8, 106, 87.8, and 66.1 mL/1.73 m(2) /min. We believe that en bloc transplantation may be an option for children with end-stage kidney disease.

[Outcomes of pediatric renal transplantation in France]

Significant progress has been observed in pediatric renal transplantation over the last 20 years, leading to an increase in graft and patient survival. Mortality is low and is mainly due to infections, neoplasias and complications related to the initial disease. Graft survival is 67% at 10 years. Factors which influence graft survival are: donor type (results are better with a live donor), donor age, recipient age (with 2 periods at risk:<2 years old and teenagers), HLA incompatibilities, and recurrence of the initial disease. Chronic allograft nephropathy (CAN) is the major cause of late graft loss. Poor compliance, especially in teenagers, may lead to late rejections and graft loss. Calcineurin inhibitors nephrotoxicity is in part responsible for the development of CAN, thus treatments and the role of mTOR inhibitors will probably evolve. These different factors are discussed in this article.