The association of donor and recipient age with graft survival in paediatric renal transplant recipients in a European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplantation Association Registry study

Favorable Outcome After Single-kidney Transplantation From Small Donors in Children: A Match-controlled CERTAIN Registry Study

BACKGROUND

Kidney transplantation (KTx) from small donors is associated with inferior graft survival in registry studies, whereas single-center studies show favorable results.

METHODS

We compared 175 pediatric KTx from small donors ≤20 kg (SDKTx) with 170 age-matched recipients from adult donors (ADKTx) from 20 centers within the Cooperative European Paediatric Renal Transplant Initiative registry. Graft survival and estimated glomerular filtration rate (eGFR) were analyzed by Cox regression and mixed models. Detailed data on surgical and medical management were tested for association with graft survival.

RESULTS

One-year graft survival was lower after SDKTx compared with ADKTx (90.9% versus 96.5%; odds ratio of graft loss, 2.92; 95% confidence interval [CI], 1.10-7.80; P  = 0.032), but 5-y graft survival was comparable (90.9% versus 92.7%; adjusted hazard ratio of graft loss 1.9; 95% CI, 0.85-4.25; P  = 0.119). SDKTx recipients had an annual eGFR increase of 8.7 ± 6.2 mL/min/1.73 m² compared with a decrease of 6.9 ± 5.7 mL/min/1.73 m² in ADKTx recipients resulting in a superior 5-y eGFR (80.5 ± 25.5 in SDKTx versus 65.7 ± 23.1 mL/min/1.73 m² in ADKTx; P  = 0.008). At 3 y posttransplant, eGFR after single SDKTx was lower than after en bloc SDKTx (86.6 ± 20.4 versus 104.6 ± 35.9; P  = 0.043) but superior to ADKTx (68.1 ± 23.9 mL/min/1.73 m²). Single-kidney SDKTx recipients had a lower rate of hypertension at 3 y than ADKTx recipients (40.0% versus 64.7%; P  = 0.008).

CONCLUSIONS

Compared with ADKTx, 5-y graft function is superior in SDKTx and graft survival is similar, even when performed as single KTx. Utilizing small donor organs, preferably as single kidneys in experienced centers, is a viable option to increase the donor pool for 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.

Influence of donor sex and age on graft outcome in kidney transplantation

BACKGROUND

There is a known recipient sex-dependent association between donor sex and kidney transplant survival. We hypothesized that donor age also modifies the association between donor sex and graft survival.

METHODS

First, deceased donor kidney transplant recipients (1988-2019, n = 461 364) recorded in the Scientific Registry of Transplant Recipients, the Australia and New Zealand Dialysis and Transplant Registry and the Collaborative Transplant Study were analyzed. We used multivariable Cox regression models to estimate the association between donor sex and death censored graft loss, accounting for the modifying effects of recipient sex and donor age; donor age was categorized as 5-19, 20-34, 35-49, 50-59 and ≥60 years. Results from cohort-specific Cox models were combined using individual patient data meta-analysis.

RESULTS

Among female recipients of donors aged <60 years, graft loss hazards did not differ by donor sex; recipients of female donors ≥60 years showed significantly lower graft loss hazards than recipients of male donors of the same age [combined adjusted hazard ratio (aHR) 0.90, 95% CI 0.86-0.94]. Among male recipients, female donors aged <50 years were associated with significantly higher graft loss hazards than same-aged male donors (5-19 years: aHR 1.11, 95% CI 1.02-1.21; 20-34 years: aHR 1.08, 95% CI 1.02-1.15; 35-49 years: aHR 1.07, 95% CI 1.04-1.10). There were no significant differences in graft loss by donor sex among male recipients of donors aged ≥50 years.

CONCLUSION

Donor age modifies the association between donor sex and graft survival. Older female donors were associated with similar or lower hazards of graft failure than older male donors in both male and female recipients, suggesting a better functional reserve of older female donor kidneys.

En bloc kidney transplantation from pediatric donors to teenage recipients: Two case reports

Introduction

Since the implementation of the new selection criteria in 2018, kidney donations from pediatric patients have been prioritized for pediatric recipients and kidney donations from pediatric donors have increased in Japan. Herein, we present two cases of en bloc kidney transplantation.

Case presentation

Case 1: A 19-year-old male patient who had been on hemodialysis for 5 years due to end-stage renal disease. After brain death, a graft from a 5-year-old boy was transplanted into the right iliac fossa. Case 2: A 19-year-old male patient, who had previously undergone a living kidney transplantation at the age of 3, received a secondary cadaveric kidney transplantation in the left iliac fossa. The graft was procured from a 17-month-old girl following cardiac death.

Conclusion

This report will help surgeons perform en bloc kidney transplantation in the growing number of pediatric kidney donations, such as those in Japan.

Time-Varying Determinants of Graft Failure in Pediatric Kidney Transplantation in Europe

BACKGROUND

Little is known about the time-varying determinants of kidney graft failure in children.

METHODS

We performed a retrospective study of primary pediatric kidney transplant recipients (younger than 18 years) from the Eurotransplant registry (1990-2020). Piece-wise exponential additive mixed models were applied to analyze time-varying recipient, donor, and transplant risk factors. Primary outcome was death-censored graft failure.

RESULTS

We report on 4528 kidney transplantations, of which 68% with deceased and 32% with living donor. One thousand six hundred and thirty-eight recipients experienced graft failure, and 168 died with a functioning graft. Between 2011 and 2020, the 5-year graft failure risk was 10% for deceased donor and 4% for living donor kidney transplant recipients. Risk of graft failure decreased five-fold from 1990 to 2020. The association between living donor transplantation and the lower risk of graft failure was strongest in the first month post-transplant (adjusted hazard ratio, 0.58; 95% confidence interval, 0.46 to 0.73) and remained statistically significant until 12 years post-transplant. Risk factors for graft failure in the first 2 years were deceased donor younger than 12 years or older than 46 years, potentially recurrent kidney disease, and panel-reactive antibody >0%. Other determinants of graft failure included dialysis before transplantation (until 5 years post-transplant), human leukocyte antigen mismatch 2-4 (0-15 years post-transplant), human leukocyte antigen mismatch 5-6 (2-12 years post-transplant), and hemodialysis (8-14 years post-transplant). Recipients older than 11 years at transplantation had a higher risk of graft failure 1-8 years post-transplant compared with other age groups, whereas young recipients had a lower risk throughout follow-up. Analysis of the combined effect of post-transplant time and recipient age showed a higher rate of graft failure during the first 5 years post-transplant in adolescents compared with young transplant recipients. In contrast to deceased donor younger than 12 years, deceased donor older than 46 years was consistently associated with a higher graft failure risk.

CONCLUSIONS

We report a long-term inverse association between living donor kidney transplantation and the risk of graft failure. The determinants of graft failure varied with time. There was a significant cumulative effect of adolescence and time post-transplant. The ideal donor age window was dependent on time post-transplant.

Risk Factor Analysis for Long-Term Graft Survival Following Pediatric Kidney Transplantation: The Importance of Pretransplantation Time on Dialysis and Donor/Recipient Age Difference

Recognizing risk factors that may negatively affect long-term graft survival following pediatric kidney transplantation is a key element in the decision-making process during organ allocation. We retrospectively reassessed all cases of pediatric kidney transplantation performed in our center in the last 20 years with the aim of determining baseline characteristics that could be identified as prognostic risk factors for long-term graft survival. Between 2001 and 2020, a total of 91 kidney transplantations in children under the age of 18 years were undertaken in our center. Early graft failure was observed in six of the 91 patients (7%). The median follow-up of the remaining 85 children was 100 months, and the overall kidney graft survival rates at 5, 10, 15 and 20 years were 85.2%, 71.4%, 46.0% and 30.6%, respectively. Small children with a body surface area of <1 m2 were significantly associated with better long-term graft survival outcomes, while adolescents aged more than twelve years showed poorer graft survival rates than younger children. Body surface area of the recipient of ≥1 m2, pretransplantation duration of the recipient on dialysis ≥18 months, hemodialysis prior to transplantation and donor/recipient age difference of ≥25 years were significantly associated with poorer long-term graft survival.

Validation of a prediction system for risk of kidney allograft failure in pediatric kidney transplant recipients: An international observational study

Predicting long-term kidney allograft failure is an unmet need for clinical care and clinical trial optimization in children. We aimed to validate a kidney allograft failure risk prediction system in a large international cohort of pediatric kidney transplant recipients. Patients from 20 centers in Europe and the United States, transplanted between 2004 and 2017, were included. Allograft assessment included estimated glomerular filtration rate, urine protein-to-creatinine ratio, circulating antihuman leukocyte antigen donor-specific antibody, and kidney allograft histology. Individual predictions of allograft failure were calculated using the integrative box (iBox) system. Prediction performances were assessed using discrimination and calibration. The allograft evaluations were performed in 706 kidney transplant recipients at a median time of 9.1 (interquartile range, 3.3-19.2) months posttransplant; mean estimated glomerular filtration rate was 68.7 ± 28.1 mL/min/1.73 m2, and median urine protein-to-creatinine ratio was 0.1 (0.0-0.4) g/g, and 134 (19.0%) patients had antihuman leukocyte antigen donor-specific antibodies. The iBox exhibited accurate calibration and discrimination for predicting the outcomes up to 10 years after evaluation, with a C-index of 0.81 (95% confidence interval, 0.75-0.87). This study confirms the generalizability of the iBox to predict long-term kidney allograft failure in children, with performances similar to those reported in adults. These results support the use of the iBox to improve patient monitoring and facilitate clinical trials in children.

Associations of longitudinal height and weight with clinical outcomes in pediatric kidney replacement therapy: results from the ESPN/ERA Registry

BACKGROUND

Associations between anthropometric measures and patient outcomes in children are inconsistent and mainly based on data at kidney replacement therapy (KRT) initiation. We studied associations of height and body mass index (BMI) with access to kidney transplantation, graft failure, and death during childhood KRT.

METHODS

We included patients < 20 years starting KRT in 33 European countries from 1995-2019 with height and weight data recorded to the ESPN/ERA Registry. We defined short stature as height standard deviation scores (SDS) < -1.88 and tall stature as height SDS > 1.88. Underweight, overweight and obesity were calculated using age and sex-specific BMI for height-age criteria. Associations with outcomes were assessed using multivariable Cox models with time-dependent covariates.

RESULTS

We included 11,873 patients. Likelihood of transplantation was lower for short (aHR: 0.82, 95% CI: 0.78-0.86), tall (aHR: 0.65, 95% CI: 0.56-0.75), and underweight patients (aHR: 0.79, 95%CI: 0.71-0.87). Compared with normal height, patients with short and tall statures showed higher graft failure risk. All-cause mortality risk was higher in short (aHR: 2.30, 95% CI: 1.92-2.74), but not in tall stature. Underweight (aHR: 1.76, 95% CI: 1.38-2.23) and obese (aHR: 1.49, 95% CI: 1.11-1.99) patients showed higher all-cause mortality risk than normal weight subjects.

CONCLUSIONS

Short and tall stature and being underweight were associated with a lower likelihood of receiving a kidney allograft. Mortality risk was higher among pediatric KRT patients with a short stature or those being underweight or obese. Our results highlight the need for careful nutritional management and multidisciplinary approach for these patients. A higher resolution version of the Graphical abstract is available as Supplementary information.

The Outcome of Transplanting Kidneys From Very Small Pediatric Deceased Donors

BACKGROUND

Kidneys from very small pediatric donors (VSPDs, aged <2 y) are underutilized. Concerns regarding potentially inferior outcomes hinder the use in pediatric recipients.

METHODS

All pediatric kidney-only transplants from <18-year-old donors between January 2012 and May 2021 in our center were included in this study. Outcomes were compared between VSPD and normal pediatric donor (NPD, aged 2-18 y) groups, and 3-y death-censored graft survival was assessed by the multivariable Cox proportional hazard model.

RESULTS

Of all 252 enrolled patients, 149 (59.1%) received kidneys from NPDs and 103 (40.9%) from VSPDs. The 3-y graft survival rates of the NPD and VSPD groups were 91.2% and 88.6%, respectively ( P = 0.385). The adjusted hazard ratio of 3-y graft loss was 1.2 (95% confidence interval, 0.6-2.5; P = 0.659) for the VSPD group compared with the NPD group. There was no significant difference in estimated glomerular filtration rate at 3 y posttransplant observed between NPD and VSPD groups (86.9 ± 26.8 versus 87 ± 27.9 mL/min/1.73 m 2 ; P = 0.991). Patients (n = 12, 4.8%) who received kidneys from donors <5 kg contributed 5 (5/39, 12.8%) with delayed graft function and the sole primary nonfunction in our cohort.

CONCLUSIONS

Although attention to preventing complications is necessary, especially for kidneys from donors <5 kg, kidneys from VSPDs did not appear to impart added risk for 3-y graft loss and renal function.

A pre-transplantation risk assessment tool for graft survival in Dutch pediatric kidney recipients

Background

A prediction model for graft survival including donor and recipient characteristics could help clinical decision-making and optimize outcomes. The aim of this study was to develop a risk assessment tool for graft survival based on essential pre-transplantation parameters.

Methods

The data originated from the national Dutch registry (NOTR; Nederlandse OrgaanTransplantatie Registratie). A multivariable binary logistic model was used to predict graft survival, corrected for the transplantation era and time after transplantation. Subsequently, a prediction score was calculated from the β-coefficients. For internal validation, derivation (80%) and validation (20%) cohorts were defined. Model performance was assessed with the area under the curve (AUC) of the receiver operating characteristics curve, Hosmer-Lemeshow test and calibration plots.

Results

In total, 1428 transplantations were performed. Ten-year graft survival was 42% for transplantations before 1990, which has improved to the current value of 92%. Over time, significantly more living and pre-emptive transplantations have been performed and overall donor age has increased (P < .05).The prediction model included 71 829 observations of 554 transplantations between 1990 and 2021. Other variables incorporated in the model were recipient age, re-transplantation, number of human leucocyte antigen (HLA) mismatches and cause of kidney failure. The predictive capacity of this model had AUCs of 0.89, 0.79, 0.76 and 0.74 after 1, 5, 10 and 20 years, respectively (P < .01). Calibration plots showed an excellent fit.

Conclusions

This pediatric pre-transplantation risk assessment tool exhibits good performance for predicting graft survival within the Dutch pediatric population. This model might support decision-making regarding donor selection to optimize graft outcomes.

Trial registration

ClinicalTrials.gov Identifier: NCT05388955.

The UK kidney donor risk index poorly predicts long-term transplant survival in paediatric kidney transplant recipients

Background

The UK kidney offering scheme introduced a kidney donor risk index (UK-KDRI) to improve the utility of deceased-donor kidney allocations. The UK-KDRI was derived using adult donor and recipient data. We assessed this in a paediatric cohort from the UK transplant registry.

Methods

We performed Cox survival analysis on first kidney-only deceased brain-dead transplants in paediatric (<18 years) recipients from 2000-2014. The primary outcome was death-censored allograft survival >30 days post-transplant. The main study variable was UK-KDRI derived from seven donor risk-factors, categorised into four groups (D1-low risk, D2, D3 and D4-highest risk). Follow-up ended on 31-December-2021.

Results

319/908 patients experienced transplant loss with rejection as the main cause (55%). The majority of paediatric patients received donors from D1 donors (64%). There was an increase in D2-4 donors during the study period, whilst the level of HLA mismatching improved. The KDRI was not associated with allograft failure. In multi-variate analysis, increasing recipient age [adjusted HR and 95%CI: 1.05(1.03-1.08) per-year, p<0.001], recipient minority ethnic group [1.28(1.01-1.63), p<0.05), dialysis before transplant [1.38(1.04-1.81), p<0.005], donor height [0.99 (0.98-1.00) per centimetre, p<0.05] and level of HLA mismatch [Level 3: 1.92(1.19-3.11); Level 4: 2.40(1.26-4.58) versus Level 1, p<0.01] were associated with worse outcomes. Patients with Level 1 and 2 HLA mismatches (0 DR +0/1 B mismatch) had median graft survival >17 years regardless of UK-KDRI groups. Increasing donor age was marginally associated with worse allograft survival [1.01 (1.00-1.01) per year, p=0.05].

Summary

Adult donor risk scores were not associated with long-term allograft survival in paediatric patients. The level of HLA mismatch had the most profound effect on survival. Risk models based on adult data alone may not have the same validity for paediatric patients and therefore all age-groups should be included in future risk prediction models.

Overcoming limits: First ABO incompatible living donor paired kidney transplant in an hypersensitized pediatric recipient in Spain

INTRODUCTION

HLA sensitization is a growing problem in children awaiting kidney transplantation. In some cases, finding an immunologically compatible donor entails contemplating the option of an ABO incompatible transplant or paired transplant.

METHODS

Patient with genetic nephrotic syndrome and progressive chronic kidney disease, with a previous thrombosis of a first kidney transplant, resulting hypersensitized and remaining for a long-time on hemodialysis. Despite a desensitization strategy, family members were incompatible and deceased donation options must be ruled out due to the presentation of donor-specific antibodies (DSA). After 4 years, the possibility arises to perform a kidney paired transplant with a 62-year-old woman with an incompatible blood group. Although the current cytotoxicity- and cell-based crossmatches were negative, history of DSA were recorded.

RESULTS

An intensive ABO and HLA desensitization protocol was performed in order to combat the isohemagglutinin antibodies and on the memory-HLA, based on rituximab, apheresis sessions, and immunoglobulins. Despite the donor being older in terms of pediatric transplantation, the donor-recipient weight difference, and immunological risk, the transplant was completed successfully. Maintenance of titration of up to 1/2 was confirmed after 3 weeks post-transplant (IgM and IgG). Kidney biopsy at 2 weeks and 6 months without signs of rejection. The patient is currently 12 months post-transplant and has not presented any signs of transplant rejection and has proper renal function.

CONCLUSIONS

Kidney paired transplantation is an excellent solution for hypersensitized children, and ABO incompatibility can be considered to increase their options to find a good donor, without thereby obtaining worse results.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Epidemiology of pediatric chronic kidney disease/kidney failure: learning from registries and cohort studies

Although the concept of chronic kidney disease (CKD) in children is similar to that in adults, pediatric CKD has some peculiarities, and there is less evidence and many factors that are not clearly understood. The past decade has witnessed several additional registry and cohort studies of pediatric CKD and kidney failure. The most common underlying disease in pediatric CKD and kidney failure is congenital anomalies of the kidney and urinary tract (CAKUT), which is one of the major characteristics of CKD in children. The incidence/prevalence of CKD in children varies worldwide. Hypertension and proteinuria are independent risk factors for CKD progression; other factors that may affect CKD progression are primary disease, age, sex, racial/genetic factors, urological problems, low birth weight, and social background. Many studies based on registry data revealed that the risk factors for mortality among children with kidney failure who are receiving kidney replacement therapy are younger age, female sex, non-White race, non-CAKUT etiologies, anemia, hypoalbuminemia, and high estimated glomerular filtration rate at dialysis initiation. The evidence has contributed to clinical practice. The results of these registry-based studies are expected to lead to new improvements in pediatric CKD care.

Encouraging outcomes of using a small-donor single graft in pediatric kidney transplantation

BACKGROUND

The use of small pediatric kidneys as single grafts for transplantation is controversial, due to the potential risk for graft thrombosis and insufficient nephron mass.

METHODS

Aiming to test the benefits of transplanting these kidneys, 375 children who underwent kidney transplantation in a single center were evaluated: 49 (13.1%) received a single graft from a small pediatric donor (≤ 15 kg, SPD group), 244 (65.1%) from a bigger pediatric donor (> 15 kg, BPD group), and 82 (21.9%) from adult living donors (group ALD).

RESULTS

Groups had similar baseline main characteristics. After 5 years of follow-up, children from the SPD group were comparable to children from BPD and ALD in patient survival (94%, 96%, and 98%, respectively, p = 0.423); graft survival (89%, 88%, and 93%, respectively, p = 0.426); the frequency of acute rejection (p = 0.998); the incidence of post-transplant lymphoproliferative disease (p = 0.671); the odds ratio for severely increased proteinuria (p = 0.357); the rates of vascular thrombosis (p = 0.846); and the necessity for post-transplant surgical intervention prior to discharge (p = 0.905). The longitudinal evolution of eGFR was not uniform among groups. The three groups presented a decrease in eGFR, but the slope of the curve was steeper in ALD children. At 5 years, the eGFR of the ALD group was 10 ml/min/1.73m² inferior to the others. At that time, the eGFR from the SPD group was statistically similar to the BPD group (p = 0.952).

CONCLUSION

In a specialized transplant center, the use of a single small pediatric donor kidney for transplantation is as successful as bigger pediatric or adult living donors, after 5 years of follow-up. A higher resolution version of the Graphical abstract is available as Supplementary information.

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.

Kidney Transplantation in Small Children: Association Between Body Weight and Outcome-A Report From the ESPN/ERA-EDTA Registry

BACKGROUND

Many centers accept a minimum body weight of 10 kg as threshold for kidney transplantation (Tx) in children. As solid evidence for clinical outcomes in multinational studies is lacking, we evaluated practices and outcomes in European children weighing below 10 kg at Tx.

METHODS

Data were obtained from the European Society of Paediatric Nephrology/European Renal Association and European Dialysis and Transplant Association Registry on all children who started kidney replacement therapy at <2.5 y of age and received a Tx between 2000 and 2016. Weight at Tx was categorized (<10 versus ≥10 kg) and Cox regression analysis was used to evaluate its association with graft survival.

RESULTS

One hundred of the 601 children received a Tx below a weight of 10 kg during the study period. Primary renal disease groups were equal, but Tx <10 kg patients had lower pre-Tx weight gain per year (0.2 versus 2.1 kg; P < 0.001) and had a higher preemptive Tx rate (23% versus 7%; P < 0.001). No differences were found for posttransplant estimated glomerular filtration rates trajectories (P = 0.23). The graft failure risk was higher in Tx <10 kg patients at 1 y (graft survival: 90% versus 95%; hazard ratio, 3.84; 95% confidence interval, 1.24-11.84), but not at 5 y (hazard ratio, 1.71; 95% confidence interval, 0.68-4.30).

CONCLUSIONS

Despite a lower 1-y graft survival rate, graft function, and survival at 5 y were identical in Tx <10 kg patients when compared with Tx ≥10 kg patients. Our results suggest that early transplantation should be offered to a carefully selected group of patients weighing <10 kg.

Long-Term Care of the Pediatric Kidney Transplant Recipient

Pediatric kidney transplant recipients are distinguished from adult recipients by the need for many decades of graft function, the potential effect of CKD on neurodevelopment, and the changing immune environment of a developing human. The entire life of an individual who receives a transplant as a child is colored by their status as a transplant recipient. Not only must these young recipients negotiate all of the usual challenges of emerging adulthood (transition from school to work, romantic relationships, achieving independence from parents), but they must learn to manage a life-threatening medical condition independently. Regardless of the age at transplantation, graft failure rates are higher during adolescence and young adulthood than at any other age. All pediatric transplant recipients must pass through this high-risk period. Factors contributing to the high graft failure rates in this period include poor adherence to treatment, potentially exacerbated by the transfer of care from pediatric- to adult-oriented care providers, and perhaps an increased potency of the immune response. We describe the characteristics of pediatric kidney transplant recipients, particularly those factors that may influence their care throughout their lives. We also discuss the risks associated with the transition from pediatric- to adult-oriented care and provide some suggestions to optimize the transition to adult-oriented transplant care and long-term outcomes.

Improved renal allograft survival for pre-emptive paediatric renal transplant recipients in the UK

BACKGROUND

The aim of this study was to investigate whether being on dialysis at the time of renal transplantation affected renal allograft survival in paediatric renal transplant recipients (pRTRs).

METHODS

Retrospective study of UK Transplant Registry (National Health Service Blood and Transplant) data on all children (aged <18 years) receiving a kidney-only transplant from 1 January 2000 to 31 December 2015. Kaplan-Meier estimates of patient and renal allograft survival calculated and Cox regression modelling accounting for donor type. The relationship between time on dialysis and renal allograft survival was examined.

RESULTS

2038 pRTRs were analysed: 607 (30%) were pre-emptively transplanted, 789 (39%) and 642 (32%) on peritoneal dialysis and haemodialysis, respectively, at the time of transplantation. Five-year renal allograft survival was significantly better in the pre-emptively transplanted group (90.6%) compared with those on peritoneal dialysis and haemodialysis (86.4% and 85.7%, respectively; p=0.02). After accounting for donor type, there was a significantly lower hazard of 5-year renal allograft failure in pre-emptively transplanted children (HR 0.742, p=0.05). Time spent on dialysis pre-transplant negatively correlated with renal allograft survival (p=0.002). There was no significant difference in 5-year renal allograft survival between children who were on dialysis for less than 6 months and children transplanted pre-emptively (87.5% vs 90.5%, p=0.25).

CONCLUSIONS

Pre-emptively transplanted children have improved 5-year renal allograft survival, compared with children on dialysis at the time of transplantation. Although increased time spent on dialysis correlated with poorer renal allograft survival, there was no evidence that short periods of dialysis pre-transplant affected renal allograft survival.

Small donors for small recipients - excellent growth and long-term function of single kidney grafts

Small-donor kidneys (≤20 kg donor weight, SDK) are preferably transplanted en bloc in adults. Concerns about thrombotic complications or hyperfiltration hinder their use in children, particularly as single grafts. Low centre experience and donor-to-recipient size are rated critical regarding outcomes. We evaluated SDK transplantation (SDTx) in paediatric recipients at a specialized transplant centre. Between 2008 and 2018, SDTx was performed in 40 children (mean age 5.4 ± 1.4 years, single grafts n = 38, donor weight ≤10 kg: n = 10). Perioperative complications were rare (n = 3), mainly thromboses despite immediate heparinization and resulted in graft loss in one patient. Overall, early and long-term GFR were excellent (76 ± 21 and 100 ± 11 ml/min/1.73 m² , first month and year 5, respectively). Three patients presented with delayed graft function. Graft volume increased significantly (69 ± 38 vs. 111 ± 33 ml within 5 years; P < 0.0001). Patients showed catch-up growth to normal range (SDS for height -2.06 ± 1.6 to -1.60 ± 1.5). Stratification by recipient age and donor weight revealed superior results in young recipients (≤3 years) and ≤10 kg donors, respectively. Outcome of single SDK grafts was excellent. Gain of GFR and graft volume was even higher in patients with very small donor or recipient size, regardless of a reduced donor-to-recipient weight ratio. Therefore, SDTx should be considered favouring small paediatric recipients.

Immunological Risk Factors in Paediatric Kidney Transplantation

Purpose

The aim of this study was to identify factors impacting recipient sensitization rates and paediatric renal transplant patient outcomes.

Patients and Methods

For this purpose, a retrospective analysis of 143 paediatric renal transplants was carried out. This included the evaluation of patient’s and donor’s demographic data, HLA mismatches, immunosuppressive therapy, rejection episodes, panel reactive antibody (PRA) and post-transplant lymphoproliferative disease (PTLD).

Results

The mean patient age at the point of transplant receival was 11.5 years with a mean follow up time of 9.33±5.05 years. It was noted that graft survival rates for donors over 59 years had the worst outcome. HLA match did not show statistically significant influence on graft outcome. Graft survival for more than one biopsy-proven rejection was also significantly shorter (p=0.008). PRA were found in 28% of the recipient’s post-transplantation and showed association with lower graft survival rates (p<0.001). In the present study, 22.7% (5/22) of the patients with EBV infections presented a PTLD.

Conclusion

In conclusion, good graft survival with reduced sensitization for future transplantations and minimize the risk of PTLD, can be ensured through a balance between donor age, HLA match and condition of the recipient should be sought. Furthermore, paediatric patients should preferably receive organs from donors between the age of 10 and 59. EBV infection could be a relevant factor for developing PTLD.

Pediatric kidney transplantation in China: an analysis from the IPNA Global Kidney Replacement Therapy Registry

BACKGROUND

The International Pediatric Nephrology Association (IPNA) Global Kidney Replacement Therapy (KRT) Registry was established to evaluate the incidence and outcomes of kidney replacement therapy (dialysis and transplantation) provided to children worldwide. Analysis of registry data for separate regions is feasible.

METHODS

Three centers located in Shanghai, Guangzhou, and Zhengzhou, which have the greatest number of pediatric kidney transplantation cases in China, participated in this analysis of transplant data. Data were registered by each center for patients under the age of 19 years who received a single-organ kidney transplant for the first time between 2011 and 2018.

RESULTS

In total, 415 patients (59.8% male) aged 1.4-18.7 (median 12.1) years were followed for 0.3-97.1 (median 27.7) months. The number of kidney transplants increased from a total of 129 during 2011-2014 to 286 cases during 2015-2018. 85.8% of patients received the transplanted kidney from a pediatric (age < 19 years) donor, and deceased donors accounted for 94% of all donors. 8.0% of grafts were lost. One and 5-year patient survival rates were 97.6% and 95.5%, respectively. The major cause of death was infection (7/14). Similar graft and patient survival rates were observed for organs from pediatric and adult donors in 6-11 and 12-18 year recipient age groups, whereas recipients < 6 years showed inferior patient and graft survival.

CONCLUSIONS

Pediatric kidney transplantation shows favorable short-term and medium-term outcomes in China. Our experience supports use of pediatric donors in pediatric kidney transplantation, but attention directed to the outcome of recipients aged under 6 is necessary. Graphical abstract.

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.

Does HLA matching matter in the modern era of renal transplantation?

Children with end-stage kidney disease should be offered the best chance for future survival which ideally would be a well-matched pre-emptive kidney transplant. Paediatric and adult practice varies around the world depending on geography, transplant allocation schemes and different emphases on living (versus deceased) donor renal transplantation. Internationally, paediatric patients often have priority in allocation schemes and younger donors are preferentially allocated to paediatric recipients. HLA matching can be difficult and may result in longer waiting times. Additionally, with improved surgical techniques and modern immunosuppressive regimens, how important is the contribution of HLA matching to graft longevity? In this review, we discuss the relative importance of HLA matching compared with donor quality; and long-term patient outcomes including re-transplantation rates. We share empirical evidence that will be useful for clinicians and families to make decisions about best donor options. We discuss why living donation still provides the best allograft survival outcomes and what to do in the scenario of a highly mismatched living donor.

Associations with kidney transplant survival and eGFR decline in children and young adults in the United Kingdom: a retrospective cohort study

Background

Although young adulthood is associated with transplant loss, many studies do not examine eGFR decline. We aimed to establish clinical risk factors to identify where early intervention might prevent subsequent adverse transplant outcomes.

Methods

Retrospective cohort study using UK Renal Registry and UK Transplant Registry data, including patients aged < 30 years transplanted 1998–2014. Associations with death-censored graft failure were investigated with multivariable Cox proportional hazards. Multivariable linear regression was used to establish associations with eGFR slope gradients calculated over the last 5 years of observation per individual.

Results

The cohort (n = 5121, of whom n = 371 received another transplant) was 61% male, 80% White and 36% had structural disease. Live donation occurred in 48%. There were 1371 graft failures and 145 deaths with a functioning graft over a 39,541-year risk period. Median follow-up was 7 years. Fifteen-year graft survival was 60.2% (95% CI 58.1, 62.3).

Risk associations observed in both graft loss and eGFR decline analyses included female sex, glomerular diseases, Black ethnicity and young adulthood (15–19-year and 20–24-year age groups, compared to 25–29 years). A higher initial eGFR was associated with less risk of graft loss but faster eGFR decline. For each additional 10 mL/min/1.73m² initial eGFR, the hazard ratio for graft loss was 0.82 (95% CI 0.79, 0.86), p < 0.0001. However, compared to < 60 mL/min/1.73m², higher initial eGFR was associated with faster eGFR decline (> 90 mL/min/1.73m²; − 3.55 mL/min/1.73m²/year (95% CI -4.37, − 2.72), p < 0.0001).

Conclusions

In conclusion, young adulthood is a key risk factor for transplant loss and eGFR decline for UK children and young adults. This study has an extended follow-up period and confirms common risk associations for graft loss and eGFR decline, including female sex, Black ethnicity and glomerular diseases. A higher initial eGFR was associated with less risk of graft loss but faster rate of eGFR decline. Identification of children at risk of faster rate of eGFR decline may enable early intervention to prolong graft survival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-020-02156-2.

Paediatric kidney transplants from donors aged 1 year and under: an analysis of the Australian and New Zealand Dialysis and Transplant Registry from 1963 to 2018

Kidneys from very small donors have the potential to significantly expand the donor pool. We describe the collective experience of transplantation using kidneys from donors aged ≤1 year in Australian and New Zealand. The ANZDATA registry was analysed on all deceased donor kidney transplants from donors aged ≤1 year. We compared recipient characteristics and outcomes between 1963-1999 and 2000-2018. From 1963 to 1999, 16 transplants were performed [9 (56%) adults, 7 (44%) children]. Death-censored graft survival was 50% and 43% at 1 and 5 years, respectively. Patient survival was 90% and 87% at 1 and 5 years, respectively. From 2000 to 2018, 26 transplants were performed [25 (96%) adults, 1 (4%) children]. Mean creatinine was 73 µmol/l ±49.1 at 5 years. Death-censored graft survival was 85% at 1 and 5 years. Patient survival was 100% at 1 and 5 years. Thrombosis was the cause of graft loss in 12% of recipients in the first era from 1963 to 1999, and 8% of recipients in the second era from 2000 to 2018. We advocate the judicious use of these small paediatric grafts from donors ≤1 year old. Optimal selection of donor and recipients may lead to greater acceptance and success of transplantation from very young donors.

The association between human leukocyte antigen eplet mismatches, de novo donor-specific antibodies, and the risk of acute rejection in pediatric kidney transplant recipients

BACKGROUND

The longitudinal relationship between HLA class I and II eplet mismatches, de novo donor-specific antibodies (dnDSA) development, and acute rejection after transplantation in childhood is unknown.

METHODS

Eplet mismatches at HLA class I and II loci were calculated retrospectively for each donor/recipient pair transplanted between 2005 and 2015 at a single Australian center. Logistic regression analyses were conducted to determine the association between the number of eplet mismatches, dnDSA, and acute rejection.

RESULTS

The cohort comprised 59 children (aged 0-18 years) who received their first kidney allograft and were followed for median (interquartile range) 4.5 (± 2.6) years. Overall, 32% (19/59) developed dnDSA (class I 3% (2/59), class II 14% (8/59), 15% class I and II (9/59)), and 24% (14/59) developed biopsy-proven acute rejection. Every unit increase in class I and II eplet mismatches corresponded to an increase in risk of class I (odds ratio (OR) 1.22, 95% CI 1.07-1.39, p < 0.01) and class II (OR 1.06, 95% CI 1.01-1.11, p = 0.02) dnDSA development. Compared with recipients without dnDSA, class I and II dnDSA were associated with direction of effect towards increased risk of acute cellular rejection (class I: OR 5.87, 95% CI 0.99-34.94, p = 0.05; class II: OR 12.00, 95% CI 1.25-115.36, p = 0.03) and acute antibody-mediated rejection (class I: OR 25.67, 95% CI 3.54-186.10, p < 0.01; class II: OR 9.71, 95% CI 1.64-57.72, p = 0.01).

CONCLUSIONS

Increasing numbers of HLA class I or II eplet mismatches were associated with the development of dnDSA. Children who developed dnDSA were also more likely to develop acute rejection compared with children without dnDSA.

Results in the ESPN/ERA-EDTA Registry suggest disparities in access to kidney transplantation but little variation in graft survival of children across Europe

One of the main objectives of the European health policy framework is to ensure equitable access to high-quality health services across Europe. Here we examined country-specific kidney transplantation and graft failure rates in children and explore their country- and patient-level determinants. Patients under 20 years of age initiating kidney replacement therapy from January 2007 through December 2015 in 37 European countries participating in the ESPN/ERA-EDTA Registry were included in the analyses. Countries were categorized as low-, middle-, and high-income based on gross domestic product. At five years of follow-up, 4326 of 6909 children on kidney replacement therapy received their first kidney transplant. Overall median time from kidney replacement therapy start to first kidney transplantation was 1.4 (inter quartile range 0.3-4.3) years. The five-year kidney transplantation probability was 48.8% (95% confidence interval: 45.9-51.7%) in low-income, 76.3% (72.8-79.5%) in middle-income and 92.3% (91.0-93.4%) in high-income countries and was strongly associated with macro-economic factors. Gross domestic product alone explained 67% of the international variation in transplantation rates. Compared with high-income countries, kidney transplantation was 76% less likely to be performed in low-income and 58% less likely in middle-income countries. Overall five-year graft survival in Europe was 88% and showed little variation across countries. Thus, despite large disparities transplantation access across Europe, graft failure rates were relatively similar. Hence, graft survival in low-risk transplant recipients from lower-income countries seems as good as graft survival among all (low-, medium-, and high-risk) graft recipients from high-income countries.

Non-standard criteria donors in pediatric kidney transplantation

KT remains the treatment of choice for ESRD in children. However, the demand for kidney transplants continues to outstrip supply, even in the pediatric scenario. We reviewed the applicability of nonSCDs for pediatric KT. There is a lack of studies analyzing this modality among pediatric donors and recipients, where most conclusions are based on predictions from adult data. Nevertheless, marginal donors might be a reasonable option in selected cases. For example, the use of older LDs is an acceptable option, with outcomes comparable to SCDs. Organs donated after cardiac death represent another possibility, albeit with logistic, ethical, and legal limitations in some countries. AKI donors also constitute an option in special situations, although there are no pediatric data on these transplants. Likewise, there are no data on the use of expanded criteria donors in pediatric patients, but this appears not to be a good option, considering the compromised long-term survival.

Utilisation of small paediatric donor kidneys for transplantation

With the increasing need for kidney transplantation in the paediatric population and changing donor demographics, children without a living donor option will potentially be offered an adult deceased donor transplant of marginal quality. Given the importance of long-term graft survival for paediatric recipients, consideration is now being given to kidneys from small paediatric donors (SPDs). There exist a lack of consensus and a reluctance amongst some centres in transplanting SPDs due to high surgical complication rates, graft loss and concerns regarding low nephron mass and long-term function. The aim of this review is to examine and present the evidence base regarding the transplantation of these organs. The literature in both the paediatric and adult renal transplant fields, as well as recent relevant conference proceedings, is reviewed. We discuss the surgical techniques, long-term graft function and rates of complications following transplantation of SPDs. We compare graft survival of SPDs to adult deceased donors and consider the use of small paediatric donors after circulatory death (DCD) organs. In conclusion, evidence is presented that may refute historically held paradigms regarding the transplantation of SPDs in paediatric recipients, thereby potentially allowing significant expansion of the donor pool.

The impact of donor/recipient age difference and HLA mismatch on graft outcome in pediatric kidney transplantation

BACKGROUND

Understanding the relationship between the factors that influence long-term kidney transplant survival remains a key priority for pediatric nephrologists. We assessed the relative impact of donor/recipient age difference and HLA matching on long-term graft outcomes.

METHODS

We conducted a retrospective cohort study of pediatric and adolescent recipients who received a primary kidney transplant in Australia and New Zealand between January 1, 1990, and December 31, 2015. The primary outcome was graft survival analyzed by Kaplan-Meier method.

RESULTS

During the 26-year period, 1134 primary (395 DD and 739 LD) kidney transplants were performed in recipients less than 20 years of age. The median follow-up time was 10.2 years. Overall, 405 patients (35.7%) lost their transplant with graft survival 93.8% at 1 year, 82.5% at 5 years, 65.8% at 10 years, and 49.9% at 15 years post-transplant. There was consistently higher graft loss of DD kidneys as compared to LD kidneys at each time point. Both increasing donor/recipient age difference (aHR 1.11 per 10 years; 95% CI, 1.02-1.20; P = 0.009) and increasing HLA mismatch (aHR 1.20 per mismatch; 95% CI, 1.10-1.30; P < 0.001) were associated with decreased graft survival.

CONCLUSIONS

Donor/recipient age difference and HLA matching are important factors influencing long-term graft outcomes in pediatric kidney transplantation. HLA mismatch remains a strong predictor of graft loss. For patients without the option of a LD, we suggest that the degree of HLA mismatch should not be discounted as part of the decision-making process of organ allocation.

Detection of occult renovascular disease in unexplained chronic kidney disease

Atherosclerotic renal artery stenosis (RAS) is a recognized cause of renal impairment. RAS is often overlooked in unexplained chronic kidney disease (CKD). A retrospective analysis of renal angiograms was performed to determine the prevalence of occult renovascular disease in 64 (M:F, 46:18; ages 21-81 years [median 60 years]) patients with unexplained CKD. Twelve patients had diabetes mellitus (type II: 11) and 43 were smokers. Median serum creatinine was 5.2 mg/dl (range 1.5-10.6 mg/dl). Group A included patients with unexplained CKD and with no risk factors for RAS and Group B had patients with increased risk for RAS. A narrowing of the renal vessel, main artery or branch, by >50% on renal arteriography was used as diagnostic criteria for RAS. 31/64 patients had positive angiographic findings. Thirteen patients had unilateral RAS, 9 had bilateral RAS, 5 had unilateral stenosis with occlusion on the opposite side, 3 had unilateral occlusion and 1 had a solitary kidney with RAS. 19/34 (54%) in Group A and 12/30 (40%) in Group B had a positive renal angiogram. In 10 patients with a rise in serum creatinine on recent introduction of ACE inhibition, 2 had evidence of RAS on renal arteriography. Eleven patients underwent angioplasty and 2 reconstructive surgeries. In 4 patients, blood pressure control improved and anti-hypertensive drug requirements were reduced, whilst renal replacement therapy was postponed in 4, by 2-24 months. In 18 patients, the lesions were not amenable to angioplasty or reconstructive surgery. Four patients did not benefit in any form with intervention. Occult atheromatous renal vascular disease is a common, not readily predictable and potentially correctable etiology of unexplained CKD.