Transplantation of adult-sized kidneys in low-weight pediatric recipients achieves short-term outcomes comparable to size-matched grafts

Effect of donor-recipient size mismatch on long-term graft survival in pediatric kidney transplantation: a multicenter cohort study

BACKGROUND

Donor-recipient size mismatching is commonly occurs in pediatric kidney transplantation (KT). However, its effect on graft survival remains unknown. This study aimed to determine the effect of donor-recipient size mismatch on the long-term survival rate of transplant kidneys in pediatric KT.

METHODS

A total of 241 pediatric patients who received KT were enrolled. The medical records of all patients were retrospectively reviewed, and the correlation between donor-recipient size mismatch and graft function and long-term graft outcome was analyzed according to donor-recipient size mismatch.

RESULTS

Recipients and donors' mean body weight at the time of KT were 34.31 ± 16.85 and 56.53 ± 16.73 kg, respectively. The mean follow-up duration was 96.49 ± 52.98 months. A significant positive correlation was observed between donor-recipient body weight ratio (DRBWR) or donor-recipient body surface area ratio (DRBSR) and graft function until 1 year after KT. However, this correlation could not be confirmed at the last follow-up. The results of long-term survival analysis using Fine and Gray's subdistribution hazard model showed no significant difference of the survival rate of the transplant kidney according to DRBWR or DRBSR.

CONCLUSION

Donor-recipient size mismatch in pediatric KT is not an important factor in determining the long-term prognosis of transplant kidneys.

Pediatric renal transplantation-A UNOS database analysis of donor-recipient size mismatch

BACKGROUND

We used the BSAi (Donor BSA/Recipient BSA) to assess whether transplanting a small or large kidney into a pediatric recipient relative to his/her size influences renal transplant outcomes.

METHODS

We included 14 322 single-kidney transplants in pediatric recipients (0-17 years old) (01/2000-02/2020) from the United Network for Organ Sharing database. We divided cases into four BSAi groups (BSAi ≤ 1, 1 < BSAi ≤ 2, 2 < BSAi ≤ 3, BSAi > 3).

RESULTS

There were no differences concerning delayed graft function (DGF) or primary non-function (PNF) rates, whether the grafts were from living or brain-dead donors. In both transplants coming from living donors and brain-dead donors, cases with BSAi > 3 and cases with 2 < BSAi ≤ 3 had similar graft survival (p = .13 for transplants from living donors, p = .413 for transplants from brain-dead donors), and both groups had longer graft survival than cases with 1 < BSAi ≤ 2 and cases with BSAi ≤ 1 (p < .001). The difference in 10-year graft survival rates between cases with BSAi > 3 and cases with BSAi ≤ 1 reached around 25% in both donor types. The better graft survival in transplants with BSAi > 2 was confirmed in multivariable analysis.

CONCLUSIONS

There is no significant impact of donor-recipient size mismatch on DGF and PNF rates in pediatric renal transplants. However, graft survival is significantly improved when the donor's size is more than twice the pediatric recipient's size.

Upside-down kidney placement: An alternative in pediatric renal transplantation

PURPOSE

"Upside-down" kidney placement has been reported as an acceptable alternative in cases of technical difficulty in kidney transplantation but there are few reports in the pediatric population. The aim of our study is to analyze whether the placement of the upside-down kidney could affect graft outcome or produce more complications.

MATERIALS AND METHODS

A retrospective study was conducted of pediatric kidney transplants performed in our center between 2005 and 2017 with at least 6 months' follow-up. Epidemiological and anthropometric data, type of donor (deceased/living), graft position (normal/upside-down), reason for the upside-down placement, early, medium and long-term complications and renal function were analyzed and compared with patients transplanted in the same period with a normal graft placement.

RESULTS

From 181 transplants, 167 grafts were placed in a normal position (mean age: 10 y and mean weight: 30 kg) and 14 were placed upside-down (10 y, 37 kg) mainly because of vessel shortness after laparoscopic nephrectomy. Male predominance was observed in both groups. 57% of grafts from the control group and 64% of those from study group came from a living donor. Four vascular and two ureteral re-anastomoses were recorded in the control group and two vascular and one ureteral re-anastomosis in the study group (p > 0.05). In the latter group, no grafts have been lost due to vascular or urological causes and no patients have required dialysis.

CONCLUSIONS

When necessary, an upside-down placement for the renal graft is a safe alternative in the pediatric population.

LEVEL OF EVIDENCE

Level III.

Kidney transplantation in low weight pediatric recipients from adult donors: The short- And the long-term outcomes

Pediatric patients with end-stage renal disease wait longer for KT due to shortage of organs and ultra-selection of donors so that they are age- and size-matched. KT from adult donors is reported to be associated with technical difficulties, complications, and poorer graft survival. We aimed to determine the outcomes of low weight patients who received kidneys from adult donors through extraperitoneal approach. We perform around 40 pediatric transplants/year, mostly from adult donors. Patients were divided into the (LWC: weight < 15 kg) and (HWC: ≥15 kg). From January 2011 to June 2017, 213 patients received KT. KT procedures were performed through extraperitoneal approach. Mean age of recipients was 10 years (5 years and 12 years for LWC and HWC, respectively) and 32 years for donors. Mean weight of recipient was 26 kg (13 kg and 31 kg for LWC and HWC, respectively) and 70 kg for donors. Mean follow-up was 5.5 years. Acute rejection occurred in 18% and delayed graft function in 5%. Three patients died during follow-up. Graft survival at 1 year was 97% and 82% at 5 years. Length of stay (P = .57), surgical complications (P = .74), long-term graft survival (P = .35), and GFR at 5 years (P = .59) were similar in both groups. This study shows that low weight pediatric patients can be transplanted from adult donors with low surgical complications and with favorable patient and graft survival. Extraperitoneal approach is feasible and safe in low weight recipients.

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.

Long-term outcomes of adult-size and size-matched kidney transplants in small pediatric recipients

INTRODUCTION

Adult-size kidneys are usually used for kidney transplantation in small pediatric recipients, but the influence of graft size in transplant outcome remains controversial. Our aim is to compare long-term transplant outcomes of using adult-size and size-matched kidneys in small pediatric recipients.

MATERIALS AND METHODS

Since 1999, 61 of 226 kidney transplants were achieved in recipients weighing <20 kg with 5 years of follow-up. Patients were analyzed according to the graft size received: (group-A) adult-size (n = 32), (group-B) size-matched (n = 29). Kidney size (KS), glomerular filtration rate (GFR) proteinuria and rejection were compared between groups at transplant time (T₀), at one (T₁), two (T₂), five years (T₅), and at the end of the follow-up (T_F) (median follow-up 8.47(0-17) years). Graft and patient survival were determined and compared between groups.

RESULTS

Mean KS was significantly different between groups at T₀ (A:11.3 ± 1.1 cm, B:8.8 ± 0.9 cm), (pT₀<0.01), group-B evidenced graft growth, reaching similar sizes to group-A at T₅ (A:11.7±1 cm, B:11.2±1 cm; pT₅ = 0.13) and T_F (A:12.2 ± 1.1 cm, B:12.4 ± 1.2 cm; pT_F = 0.63), and group-A had a slight graft growth at T_F (pT₀-T_F<0.01). Mean Schwartz-GFR at T₀ was greater in group-A (138 ± 33 ml/min/1.73 m²) than group-B (109 ± 34 mL/min/1.73 m²) (pT₀ = 0.01); during follow-up, it evidenced a reduction in group-A (T₅:90 ± 27, T_F:71 ± 24 mL/min/1.73 m²; pT₀-T₅<0.01; pT₀-T_F<0.01), meanwhile in group-B was stable until T₅ (104 ± 33 mL/min/1.73 m²; pT₀-T₅ = 0.54), declining at T_F (76 ± 31 mL/min/1.73 m²; pT₀-T_F<0.01); with no significant differences at T₁, T₂, T₅, and TF between groups. Similar results were observed in mean Filler-GFR of both groups (Figure). Proteinuria and episodes of rejection were no significantly different between groups during the follow-up (p > 0.01; p = 0.23). Graft and patient survival at 5 and 10 years did not show significant differences (p = 0.45; p = 0.10).

DISCUSSION

Despite the initial kidney size difference between groups, we have demonstrated that they tended to the same size during the follow-up. Adult-size kidneys presented a slight size increase in the long-term, suggesting that they have some growth potential in small recipients, in contrast to previous literature. Mean GFR between groups showed no significant differences in the long-term, suggesting that optimal graft perfusion and function can be achieved despite the size of the graft. We have demonstrated that there were no significant differences in long-term graft and patient survival; this results were similar to the most recent literature about this topic and different from the 90-2000s decades literature.

CONCLUSIONS

Adult-size kidneys may be transplanted to small recipients (<20 kg) with comparable outcomes to size-matched kidneys, with no significant differences in long-term KS, GFR, proteinuria, rejection, graft or patient survival.

Clinical implication of renal allograft volume to recipient body surface area ratio in pediatric renal transplant

Our study aims to assess the clinical implication of RAV/rBSA ratio in PRT as a predictor for attained renal function at 1 year post-transplantation and its association with surgical complications. A retrospective cohort was performed for PRT cases from January 2000 to December 2015 in our institution. Extracted clinical information includes the recipient's demographics, donor type, renal allograft characteristics, arterial, venous and ureteral anastomoses, vascular anastomosis time while kidney off ice, overall operative time, and estimated blood loss. The RAV/rBSA was extrapolated and assessed for its association with renal graft function attained in 1 year post-transplantation and surgical complications within 30-day post-transplantation. A total of 324 PRTs cases were analyzed. The cohort consisted of 187 (52.4%) male and 137 (42.3%) female recipients, with 152 (46.9%) living donor and 172 (53.1%) deceased donor renal transplants, and an overall median age of 155.26 months (IQR 76.70-186.98) at time of renal transplantation. The receiver operating characteristic identified that a RAV/rBSA ratio of 135 was the optimal cutoff in determining the renal graft function outcome. Univariate and multivariate analyses revealed the relative OR for RAV/rBSA ≥ 135 ratio in predicting an eGFR ≥ 90 attained within 1 year post-transplant was highest among younger pediatric recipients (<142.5 months) of deceased kidney donors (OR = 11.143, 95% CI = 3.156-39.34). Conversely, Kaplan-Meier analysis revealed that RAV/rBSA ratio ≥ 135 is associated with lower odds of having eGFR <60 (OR = 0.417, 95% CI = 0.203-0.856). The RAV/rBSA ratio was not associated nor predictive of transplant-related surgical complications. Our study determined that the RAV/rBSA ratio is predictive of renal graft function at 1-year PRT, but not associated with any increased surgical complications.

Renal allograft survival rates in kidneys initially declined for paediatric transplantation

BACKGROUND

The outcome of organs which have been declined for paediatric recipients is not known. This study aimed to determine the outcome of kidneys initially declined for paediatric recipients and establish renal allograft survival in kidneys that were eventually transplanted.

METHODS

Data were obtained from the UK Transplant Registry for all donation after brain death (DBD) kidneys offered and declined to paediatric recipients (< 18 years) in the UK from 2009 to 2014.

RESULTS

Eighty-two percent (503/615) of kidneys initially declined for paediatric transplantation were eventually transplanted, 7% (46/615) of kidneys went to paediatric recipients and 62% (384/615) of kidneys went to adult (kidney only) recipients. The remainder were used for multiple organ transplants. In the 46 kidneys that went to paediatric recipients, 1 and 3-year renal allograft survivals were 89% (95% CI 75.8-95.3%) and 82% (95% CI 67.1-90.6%), respectively. In the 384 kidneys given to adult kidney-only recipients, 1 and 3-year renal allograft survivals were 96% (95% CI 93.5-97.6%) and 94% (95% CI 90.7-96.1%), respectively. Eighty-four percent of the 204 children who initially had an offer declined on their behalf were eventually transplanted and have a functioning graft at a median 3-year follow-up.

CONCLUSIONS

This study reports acceptable short-term renal allograft survival in kidneys that were initially declined for paediatric recipients and subsequently transplanted. Evidence-based guidelines are required to ensure that the most appropriate kidneys are selected for paediatric recipients.

Donor-recipient size mismatch in paediatric renal transplantation

Introduction. End stage renal failure in children is a rare but devastating condition, and kidney transplantation remains the only permanent treatment option. The aim of this review was to elucidate the broad surgical issues surrounding the mismatch in size of adult kidney donors to their paediatric recipients. Methods. A comprehensive literature search was undertaken on PubMed, MEDLINE, and Google Scholar for all relevant scientific articles published to date in English language. Manual search of the bibliographies was also performed to supplement the original search. Results. Size-matching kidneys for transplantation into children is not feasible due to limited organ availability from paediatric donors, resulting in prolonged waiting list times. Transplanting a comparatively large adult kidney into a child may lead to potential challenges related to the surgical incision and approach, vessel anastomoses, wound closure, postoperative cardiovascular stability, and age-correlated maturation of the graft. Conclusion. The transplantation of an adult kidney into a size mismatched paediatric recipient significantly reduces waiting times for surgery; however, it presents further challenges in terms of both the surgical procedure and the post-operative management of the patient's physiological parameters.

[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.