Transplantation of adult-size kidneys in small pediatric recipients: A single-center experience

Should children receive a kidney transplant before 2 years of age?

BACKGROUND

The optimal age of kidney transplantation for infants and toddlers with kidney failure is unclear. We aimed to evaluate the patient survival associated with kidney transplantation before 2 years of age versus remaining on the waitlist until ≥2 years.

METHOD

We used the Scientific Registry of Transplant Recipients to identify all children added to the deceased-donor waitlist before 2 years of age between 1/1/2000 and 4/30/2020. For each case aged <2 years at transplant, we created a control group comprising all candidates on the waitlist on the case's transplant date. Patient survival was evaluated using sequential Cox regression. Dialysis-free time was defined as graft survival time for cases and the sum of dialysis-free time on the waitlist and graft survival time for controls.

RESULTS

We observed similar patient survival for posttransplant periods 0-3 and 4-12 months but higher survival for period >12 months for <2-year decreased-donor recipients (aHR: 0.32; 95% CI: 0.13-0.78; p = .01) compared with controls. Similarly, patient survival was higher for <2-year living-donor recipients for posttransplant period >12 months (aHR: 0.21; 95% CI: 0.06-0.73; p = .01). The 5-year dialysis-free survival was higher for <2-year deceased- (difference: 0.59 years; 95% CI: 0.23-0.93) and living-donor (difference: 1.84 years; 95% CI: 1.31-2.25) recipients.

CONCLUSION

Kidney transplantation in children <2 years of age is associated with improved patient survival and reduced dialysis exposure compared with remaining on the waitlist until ≥2 years.

Postoperative surgical complications after pediatric kidney transplantation in low weight recipients (<15 kg): a systematic review

PURPOSE OF REVIEW

Kidney transplantation in low-weight recipients (<15 kg) is a challenging surgery with special characteristics. We proposed to perform a systematic review to determine the postoperative complication rate and the type of complications after kidney transplantation in low-weight recipients (<15 kg). The secondary objectives were to determine graft survival, functional outcomes, and patient survival after kidney transplantation in low-weight recipients.

METHODS

A systematic review was performed according to preferred reporting items for systematic reviews and meta-analyses. Medline and Embase databases were searched to identify all studies reporting outcomes on kidney transplantation in low-weight recipients (<15 kg).

RESULTS

A total of 1254 patients in 23 studies were included. The median postoperative complications rate was 20.0%, while 87.5% of those were major complications (Clavien ≥3). Further, urological and vascular complications rates were 6.3% (2.0-11.9) and 5.0% (3.0-10.0), whereas the rate of venous thrombosis ranged from 0 to 5.6%. Median 10-year graft and patient survival were 76 and 91.0%.

SUMMARY

Kidney transplantation in low-weight recipients is a challenging procedure complicated by a high rate of morbidity. Finally, pediatric kidney transplantation should be performed in centers with expertise and multidisciplinary pediatric teams.

Retroperitoneal kidney transplantation with liver and native kidney mobilization: a safe technique for pediatric recipients

BACKGROUND

Pediatric kidney transplant (KT) using larger, deceased or living donor adult kidneys can be challenging in the pediatric population due to limited space in the retroperitoneum. Liver and native kidney (L/NK) mobilization techniques can be used in smaller and younger transplant recipients to aid in retroperitoneal placement of the renal allograft. Here, we compare the clinical outcomes of pediatric retroperitoneal KT with and without L/NK mobilization.

METHODS

We retrospectively analyzed pediatric renal transplant recipients treated between January 2015 and May 2021. Donor and recipient demographics, intraoperative data, and recipient outcomes were included. Recipients were divided into two groups according to the surgical technique utilized: with L/NK mobilization (Group 1) and without L/NK mobilization (Group 2). Baseline variables were described using frequency distributions for categorical variables and means and standard errors for continuous variables. Tests of association with the likelihood of using L/NK mobilization were performed using standard χ2 tests, t tests, and the log-rank test.

RESULTS

Forty-six pediatric recipients were evaluated and categorized into Group 1 (n = 26) and Group 2 (n = 20). Recipients in Group 1 were younger (6.7 ± 0.8 years vs. 15. 3 ± 0.7, P < 0.001), shorter (109.5 ± 3.7 vs. 154.2 ± 3.8 cm, P < 0.001) and weighed less (21.4 ± 2.0 vs. 48.6 ± 3.4 kg, P < 0.001) than those in Group 2. Other baseline characteristics did not differ between Groups 1 and 2. One urologic complication was encountered in Group 2; no vascular or surgical complications were observed in either group. Additionally, no stents or drains were used in any of the patients. There were no cases of delayed graft function or graft primary nonfunction. The median follow-up of the study was 24.6 months post-transplant. Two patients developed death-censored graft failure (both in Group 2, P = 0.22), and there was one death with a functioning graft (in Group 2, P = 0.21).

CONCLUSIONS

Retroperitoneal liver/kidney mobilization is a feasible and safe technique that facilitates implantation of adult kidney allografts into pediatric transplant recipients with no increased risk of developing post-operative complications, graft loss, or mortality.

Novel Histopathologic and Ultrastructural Findings in Renal Allografts From Patients With Size and Age Mismatches: A Case Series

While reports on the long-term pathology in mismatched allografts have been focused on the donor and recipient body surface area, evidence is emerging to support donor-recipient age difference as an additional prognostic factor. Most reports are based on pediatric recipients receiving older/bigger allografts. Here, we describe three cases with age mismatch including two cases of adult patients receiving pediatric allografts and a third case of a younger patient receiving an allograft from an older donor exhibiting findings not described in extant literature. Each of these cases exhibits unique changes seen in mismatched donor-recipient size/age post-transplant pathology. These non-rejection changes should be suspected in cases of donor-recipient size/age mismatch. In cases of allograft function decline, a full biopsy workup, including electron microscopy, should be considered.

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.

Good outcomes after pediatric intraperitoneal kidney transplant

BACKGROUND

Kidney transplantation in small children is technically challenging. Consideration of whether to use intraperitoneal versus extraperitoneal placement of the graft depends on patient size, clinical history, anatomy, and surgical preference. We report a large single-center experience of intraperitoneal kidney transplantation and their outcomes.

METHODS

We conducted a retrospective review of pediatric patients who underwent kidney transplantation from April 2011 to March 2018 at a single large volume center. We identified those with intraperitoneal placement and assessed their outcomes, including graft and patient survival, rejection episodes, and surgical or non-surgical complications.

RESULTS

Forty-six of 168 pediatric kidney transplants (27%) were placed intraperitoneally in children mean age 5.5 ± 2.3 years (range 1.6-10 years) with median body weight 18.2 ± 5 kg (range 11.4-28.6 kg) during the study period. Two patients (4%) had vascular complications; 10 (22%) had urologic complications requiring intervention; all retained graft function. Thirteen patients (28%) had prolonged post-operative ileus. Eight (17%) patients had rejection episodes ≤6 months post-transplant. Only one case resulted in graft loss and was associated with recurrent focal segmental glomerular sclerosis (FSGS). Two patients (4%) had chronic rejection and subsequent graft loss by 5-year follow-up. At 7-year follow-up, graft survival was 93% and patient survival was 98%.

CONCLUSIONS

The intraperitoneal approach offers access to the great vessels, which allows greater inflow and outflow and more abdominal capacity for an adult donor kidney, which is beneficial in very small patients. Risk of graft failure and surgical complications were not increased when compared to other published data on pediatric kidney transplants.

Overview of pediatric kidney transplantation

Kidney transplantation is the treatment of choice for pediatric patients with end-stage kidney disease. Unlike adult recipients undergoing transplantation, special considerations must be taken when transplanting children based on the underlying etiology of kidney disease, previous surgical procedures, anatomical limitations and necessary technical adjustments. Additionally, the choice of donor must be measured to ensure optimal graft survival given a longer post-transplant life expectancy. Those topics as well as frequently encountered postoperative complications are also discussed in this publication.

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.

Surgical considerations in paediatric kidney transplantation: an update

Background

Kidney transplantation has established itself as the most appropriate mode of renal replacement therapy for the majority with end-stage kidney disease. Although at present this is applicable for children as well as adults, a few decades back kidney transplantation was not considered a first-line option in children. This was due to inferior outcomes following transplantation in this age group compared to that of adults. These poor results were attributed to challenges in paediatric transplantation such as the shortage of suitable donors, technical difficulties in performing a sound vascular anastomosis and the adverse effects of immunosuppressive medication on growth and development. However, current patient and graft-centred outcomes after paediatric transplantation equal or surpass that of adults. The advances in evaluation and management of specific surgical concerns in children who undergo transplantation, such as pre-transplant native nephrectomy, correction of congenital anomalies of the urinary tract, placement of an adult-sized kidney in a small child and minimizing the risk of allograft thrombosis, have contributed immensely for these remarkable outcomes.

Conclusions

In this review, we aim to discuss surgical factors that can be considered unique for children undergoing kidney transplantation. We believe that an updated knowledge on these issues will be invaluable for transplant clinicians, who are dealing with paediatric kidney transplantation.

Extraperitoneal kidney transplantation: a comparison between children weighting ≤15 kg and >15 kg. Experience of a single institution

Extraperitoneal approach is sometimes recommended for kidney transplantation (KT) in children weighting <15 kg. We hypothesized that this approach might be as successful as in patients with normal weight. Data of all consecutive KTs performed between 2013 and 2019 were retrospectively reviewed. Early outcomes and surgical complications were compared between children weighing ≤15 kg (low‐weight (LW) group) and those weighing >15 kg (Normal‐weight (NW) group). All the 108 KTs were performed through an extraperitoneal approach. The LW group included 31 patients (mean age 3.5 ± 1.4 years), whose mean weight was 11.1 ± 2.0 kg. In the LW group,—a primary graft nonfunction (PNGF) occurred in one patient (3.2%), surgical complications occurred in nine (29%), with four venous thrombosis. In the NW group, PNGF occurred in one case (1.3%), delayed graft function (DGF) in eight (10%), surgical complications in 11 (14%) with only one case of venous thrombosis. In both groups, no need for patch during wound closure and no wound dehiscence were reported. The extraperitoneal approach can be effectively used in LW children. No differences were observed in the overall complication rate (P = 0.10), except for the occurrence of venous thrombosis (P = 0.02). This might be related to patients’ characteristics of the LW group.

Long-term outcomes of living-donor kidney transplant children weighing less than 15 kg: Comparison of the surgical approach

INTRODUCTION

Kidney transplantation (KTx) is the most effective treatment for end-stage renal disease in children.

OBJECTIVES

We aimed to compare the long-term outcomes and surgical complications of the intraperitoneal approach (IPA) and extraperitoneal approach (EPA) for KTx in children weighing <15 kg.

STUDY DESIGN

We performed a retrospective cohort study on pediatric kidney transplant recipients, weighing <15 kg, who received their first living-related kidney transplant between January 1987 and December 2015. Patients were divided into two groups based on the surgical approach (IPA or EPA) during transplant, and clinical data were extracted from the medical records.

RESULTS

The median follow-up duration was 14.1 years (interquartile range, 9.0-19.2). Comparing the two groups (IPA group, n = 62; EPA group, n = 38), the median age and body weight were significantly lower in the IPA group (4.2 vs. 4.8 years, P = 0.03; 11.7 vs. 13.0 kg, P < 0.01). There were 26 surgical complications (26%) in 19 patients during the follow-up period. The surgical complication rate was higher in the IPA group (39% vs. 6%).

DISCUSSION

We assessed the long-term outcomes of the surgical approaches used for pediatric patients weighing <15 kg who underwent KTx and received a size-mismatched adult donor kidney. There was no significant difference in renal transplantation prognosis using the surgical approach, but IPA-related complications were more frequent in the long term. Therefore, our data suggest that in cases of donor-recipient size mismatch in pediatric KTx, the EPA, associated with fewer surgical complications, is preferable to the IPA if the patient's body size has sufficient space for allograft placement.

CONCLUSION

The transplant approach did not influence the long-term outcomes in children weighing <15 kg, but EPA had fewer surgical complications and was technically safe.

Donor considerations in pediatric kidney transplantation

This article reviews kidney transplant donor options for children with end-stage kidney disease (ESKD). Global access to kidney transplantation is variable. Well-established national policies, organizations for organ procurement and allocation, and donor management policies may account for higher deceased donor (DD transplants) in some countries. Living donor kidney transplantation (LD) predominates in countries where organ donation has limited national priority. In addition, social, cultural, religious and medical factors play a major role in both LD and DD kidney transplant donation. Most children with ESKD receive adult-sized kidneys. The transplanted kidney has a finite survival and the expectation is that children who require renal replacement therapy from early childhood will probably have 2 or 3 kidney transplants in their lifetime. LD transplant provides better long-term graft survival and is a better option for children. When a living related donor is incompatible with the intended recipient, paired kidney exchange with a compatible unrelated donor may be considered. When the choice is a DD kidney, the decision-making process in accepting a donor offer requires careful consideration of donor history, kidney donor profile index, HLA matching, cold ischemia time, and recipient's time on the waiting list. Accepting or declining a DD offer in a timely manner can be challenging when there are undesirable facts in the donor's history which need to be balanced against prolonging dialysis in a child. An ongoing global challenge is the significant gap between organ supply and demand, which has increased the need to improve organ preservation techniques and awareness for organ donation.

Strategy to Enable and Accelerate Kidney Transplant in Small Children and Results of the First 130 Transplants in Children ≤15 kg in a Single Center

BACKGROUND

Proper care of young children in need of kidney transplant (KT) requires many skilled professionals and an expensive hospital structure. Small children have lesser access to KT.

METHODS

We describe a strategy performed in Brazil to enable and accelerate KT in children ≤15 kg based on the establishment of one specialized transplant center, focused on small children, and cooperating with distant centers throughout the country. Actions on 3 fronts were implemented: (a) providing excellent medical assistance, (b) coordinating educational activities to disseminate expertise and establish a professional network, and (c) fostering research to promote scientific knowledge. We presented the number and outcomes of small children KT as a result of this strategy.

RESULTS

Three hundred forty-six pediatric KTs were performed in the specialized center from 2009 to 2017, being 130 in children ≤15 kg (38%, being 41 children ≤10 kg) and 216 in >15 kg (62%). Patient survival after 1 and 5 years of the transplant was 97% and 95% in the "small children" group, whereas, in the "heavier children" group, it was 99% and 96% (P = 0.923). Regarding graft survival, we observed in the "small children" group, 91% and 87%, whereas in the "heavier children" group, 94% and 87% (P = 0.873). These results are comparable to the literature data. Groups were similar in the incidence of reoperation, vascular thrombosis, posttransplant lymphoproliferative disease, and estimated glomerular filtration rate.

CONCLUSIONS

The strategy allowed an improvement in the number of KT in small children with excellent results. We believe this experience may be useful in other locations.

Comparison of live donor predonation and post-transplant kidney volumes and glomerular size in pediatric patients weighing less than 15 kg - a retrospective study

Renal transplantation of adult-size kidneys presents a size mismatch in small children. This study presents a comparison of live donor predonation and recipient post-transplant kidney volumes (k-vol) and glomerular size at 1 year after transplantation. We analyzed 47 pediatric renal transplant recipients weighing <15 kg between 2009 and 2017. The k-vol before and 1 year after transplantation and glomerular size at implant and 1 year post-transplant were evaluated. We estimated the relationships between these changes and graft function, and the factors associated with k-vol. Pretransplant k-vol was 158.1 ± 25.1 ml, and the k-vol at 1 year post-transplant was significantly reduced by -17.2% to 132.3 ± 27.3 ml (P < 0.001). Implant glomerular size showed the diameter was 165.3 ± 15.1 µm and the area 20 737.1 ± 3230.6 µm² . One-year post-transplant, the glomerular diameter was 150.6 ± 11.4 µm and the area 17 428.3 ± 2577.9 µm² , significantly reduced compared with implantation values (both P < 0.001). The change in k-vol was affected by pretransplant abdominal cavity (ml/200 ml cavity volume, partial regression coefficient = 0.029, SE = 0.009, P = 0.004) and recipient's weight gain (ml/5% of weight gain, partial regression coefficient = 0.020, SE = 0.006, P = 0.002). In small pediatric transplants, an adult-size kidney is acceptable with reduction in k-vol. Moreover, the post-transplant k-vol might be regulated by pretransplant physique and post-transplant somatic growth.