Expanding the Envelope: Favorable Outcomes Utilizing Kidneys From Small Pediatric Donors (≤ 15 kg)

Long-term outcome of pediatric renal transplantation with donors younger than 6 years

BACKGROUND

Renal transplantation is currently the best treatment option for patients with end-stage renal disease. However, the use of kidneys from donors under 6 years of age as a possibility to increase the organ pool in pediatric recipients remains a controversial matter. We aimed to investigate whether donor age is associated to the long-term functionality of the renal graft. Likewise, we analyzed the adaptation of the graft to the ascending functional requirements in the pediatric patient.

METHODS

Retrospective study of the results obtained in pediatric recipients transplanted with grafts from donors between 3 and 6 years of age, comparing them with those of grafts from donors older than 6 years. Among the variables compared are cumulative graft survival, renal size, need for antiproteinuric therapy, GFR, incidence of rejection, pyelonephritis, renal failure and surgical or tumor complications.

RESULTS

A total of 43 transplants were performed with donors aged 3-6 years, and 42 transplants with donors older than 6 years. Cumulative graft survival at 5 years was 81% for the younger donor group compared to 98% for the older donor group (p < .05). At 8 years, cumulative graft survival for donors <6 years was 74%. As for the mean estimated graft survival, it was 11.52 years for the younger donor group and 14.51 years for older donors. During follow-up, the younger donor group presented greater renal enlargement and need for antiproteinuric therapy. The older donors group had a higher GFR during the first year of follow-up, which then equalized in both groups. There were no statistically significant differences in the incidence of acute or chronic rejection, acute pyelonephritis, acute renal failure or surgical or tumor complications.

CONCLUSIONS

Renal transplants of grafts equal to or less than 6 years old have good short-term and acceptable long-term results in pediatric patients.

Outcomes of Transplantation of Single Kidneys From Pediatric Donors Into Adult Recipients

Background Organs from extreme ages have been sought after to help increase the donor pool and alleviate transplantation wait times. There has been a growing evolution of the use of pediatric donor kidneys, including the use of en bloc kidneys (EBK), to now separating them into single kidneys (SKT), allowing for transplantation of two recipients. This study reports our outcomes utilizing SKT. Methods A retrospective review of all SKT performed from 2014 to 2022 at our center was conducted. Donors >8 years of age or >25 kg in weight were excluded. Donor and recipient characteristics and outcomes were analyzed, comparing <18 kg and ≥18 kg donor cohorts. Results Between 2014 and 2022, 81 adults received SKT. Recipients' mean age, weight, and body mass index were 49 years (22-74), 74 kg (39-136), and 26.4 mg/m2 (19.6- 39.8), respectively. Donors' mean age, weight, and kidney size were 35.7 months (8-96), 17.8 kg (8-25), and 7.2 cm (4.5-8.5), respectively. At one year post-transplant, patient survival was 100%, graft survival was 98.7%, mean serum creatinine was 1.25 mg/dL, and mean glomerular filtration rate (GFR) was 68.3 ml/min. Hyperfiltration injury was seen in 43.75% of recipients. None of the outcomes correlated with any of the donor or recipient characteristics. Conclusion Our study shows excellent short-term outcomes of single pediatric kidney transplantation in adult recipients. Exploring a lower donor weight cut-off for SKT, compared to the current Organ Procurement and Transplantation Network's (OPTN's) ≥18 kg, could expand the organ pool and lead to an increased number of transplants.

Long-term Outcomes of Single and Dual En Bloc Kidney Transplants From Small Pediatric Donors: An ANZDATA Registry Study

Kidney transplants from small pediatric donors are considered marginal and often transplanted as dual grafts. This study aimed to compare long-term outcomes between recipients of single kidney transplants (SKTs) and dual en bloc kidney transplants (EBKTs) from small pediatric donors.

Methods

Data were obtained from the Australia and New Zealand Dialysis and Transplant Registry. All adult recipients of kidney transplants from donors aged ≤5 y were identified. The primary outcome of interest was death-censored graft survival by donor type. The secondary outcomes were early graft loss, delayed graft function, serum creatinine posttransplantation, acute rejection, and patient survival.

Results

There were 183 adult recipients of kidney transplants from donors aged ≤5 y old. Of these, 60 patients had EBKT grafts, 79 patients had SKT grafts, and 44 patients had grafts of unknown type. Compared with SKT donors, EBKT donors had lower mean age (P < 0.001) and body weight (P < 0.001). There was no significant difference in death-censored graft survival between the groups, with median survival of 23.8 y (interquartile range 21.2-25) in the EBKT cohort and 21.8 y (11.6-26.8) in the SKT cohort (hazard ratio 1.3; 95% confidence interval, 0.59-2.64; P = 0.56). EBKT grafts had lower acute rejection rates than SKT grafts (P = 0.014). There was no significant difference observed between groups with respect to early graft loss, delayed graft function, posttransplantation serum creatinine posttransplantation, or patient survival.

Conclusions

EBKT and SKTs from small pediatric donors are associated with excellent long-term graft survival rates.

Excellent Clinical Long-Term Outcomes of Kidney Transplantation From Small Pediatric Donors (Age ≤ 5 Years) Despite Early Hyperfiltration Injury

Background:

The use of small pediatric donors (age ≤ 5 years and body weight < 20kg) for adult transplant recipients is still regarded controversially in terms of early complications, long-term outcomes, and development of hyperfiltration injury due to body size mismatch.

Objective:

To investigate long-term outcomes of adult renal allograft recipients receiving a kidney from small pediatric donor (SPD) in terms of kidney function and early features of hyperfiltration injury such as histological changes and proteinuria.

Design:

Retrospective, single center study.

Settings:

Transplant center of the University Hospital of Basel, Switzerland.

Patients:

Adult renal allograft recipients receiving a kidney from a small pediatric donor at our center between 2005 and 2017.

Methods:

The outcome of 47 transplants from SPD were compared with 153 kidney transplants from deceased-standard criteria donors (SCD) occurring during the same time period. Incidence of clinical signs of hyperfiltration injury (eg, proteinuria) was investigated. According to our policy, surveillance biopsies were taken at 3 and 6 months post-transplant and were evaluated in terms of signs of hyperfiltration injury.

Results:

At a median follow-up of 2.3 years post-transplant, death-censored graft survival of SPD was comparable to transplants from SCD (94% vs 93%; P = .54). Furthermore, allograft function at last follow-up (estimated glomerular filtration rate–Modification of Diet in Renal Disease) was significantly higher in pediatric transplant (80 vs 55 ml/min/1.73 m2, P = .002). We found histological signs of early hyperfiltration injury in 55% of SPD. There was an equally low proteinuria in both groups during follow-up.

Limitations:

It is a single center and retrospective observational study with small sample size. The outcomes were investigated in a well-selected population of recipients with low body mass index, low immunological risk, and well-controlled hypertension and was not compared with equal selected group of recipients.

Conclusions:

Early histological and clinical signs of hyperfiltration injury in SPD is frequent. Despite the hyperfiltration injury, there is an equal allograft survival and even superior allograft function in SPD compared with SCD during follow-up. This observation supports the concept of high adaptive capacity of pediatric donor kidneys.

Donor Size Doesn’t Impact En Bloc Kidney Transplant Outcomes: A Single-Center Experience and Review of Literature

Few transplant programs use kidneys from donors with body weight (BW)<10 kg due to higher incidence of vascular and urological complications, and DGF. The purpose of this study was to investigate the non-inferiority of pediatric en bloc kidneys from donors with BW<10 kg. We performed a single-center retrospective analysis of en bloc kidney transplants from pediatric donor cohort (n = 46) from 2003 to 2021 and stratified the outcomes by donor BW (small group, donor BW<10 kg, n = 30; standard group, donor BW<10 kg, n = 16). Graft function, rate of early post-transplant complications, graft and patient survival were analyzed. Complication rates were similar between both groups with 1 case of arterial thrombosis in the smaller group. Overall graft and patient survival rates were similar between the small and the standard group (graft survival—90% vs. 100%, p = 0.09; patient survival—96.7 vs. 100%, p = 0.48). Serum creatinine at 1, 3, 5 years was no different between groups. Reoperation rate was higher in the small group (23.3% vs. 6.25%, p = 0.03). The allograft from small donors could be related to higher reoperation rate in the early post-transplant period, but not associated with lower long-term graft and patient survival.

The impact of multiple donor renal arteries on perioperative complications and allograft survival in paediatric renal transplantation

BACKGROUND

The impact of using allografts with multiple renal arteries in paediatric kidney transplantation has not been clearly established. The aim of this study was to determine whether kidney grafts with multiple arteries pose any adverse effects upon perioperative surgical outcomes, and graft survival up to 12 months post-transplant.

OBJECTIVE

The objective of this study was to perform a comparative analysis of a minimum of 12-month graft survival and transplant renal function in paediatric renal transplant recipients receiving single versus multiple donor arteries, and to assess perioperative and early post-operative surgical outcomes.

STUDY DESIGN

A retrospective divisional chart review of 379 transplants performed (2000-2018), of which 90 (23.7%) contained multiple donor arteries. The number of arteries of the graft, donor type, vascular reconstruction technique, occurrence of urological and vascular complications, estimated GFR and graft survival up to 12 months post-transplantation, graft loss and mortality were analysed. Comparisons in baseline characteristics and outcome measures were made between both groups.

RESULTS

No significant differences were found in age (p = 0.42), BMI (p = 0.39), estimated intraoperative blood loss (p = 0.14), overall (p = 0.63) or warm ischaemic time (p = 0.37). 51.3% patients with multiple donor arteries underwent an ex vivo reconstruction. There were no differences in the site of arterial anastomosis (aorta, external iliac, internal iliac), or anastomotic type (end-side; end-end). Whilst there was a significantly higher post-operative lymphocoele rate in the multiple vessel cohort (p = 0.024), there was no increase in post-transplant urine leaks, rejection episodes, graft loss (1.1% multiple vs 2.1% single), perioperative complications (p = 0.68), or estimated GFR at 1 month (p = 0.9) or at 1 year (p = 0.67).

DISCUSSION

We demonstrated in this study that there was no significant difference in postoperative complications up to 3 months, eGFR and renal function up to 1 year, and graft survival up to 4 years post transplantation irrespective of allograft type or reconstruction technique. There was however, a higher rate of lymphocoeles in the multiple artery cohort. The results seen here broadly mirror trends seen in adult studies, however, there is little data available from paediatric series.

CONCLUSION

Our study demonstrates that multiple renal artery allografts - previously been considered to carry a high complication risk - can be safely used for paediatric renal transplantation with equivalent perioperative complications and graft outcomes to single artery allografts.

Successful single kidney transplantation from pediatric donors less than or equal to 10 kg to adult recipient: a retrospective cohort study

BACKGROUND

Kidneys from very small pediatric donors (≤10 kg) are underutilized. Compared to en bloc kidney transplantation (EBKT), single kidney transplantation (SKT) can maximize donor resources. However, it remains unknown whether it's appropriate to perform SKTs from donors weighing ≤10 kg.

METHODS

A total of 35 adult recipients undergoing kidney transplantation from donors weighing ≤10 kg at our center from December 2014 to December 2019 were included and grouped into SKT group (n=20) and EBKT group (n=15). Transplant outcomes were retrospectively analyzed and compared between 2 groups.

RESULTS

The 1-year and 3-year death-censored graft survival in SKT group was 95%, it is not significantly higher than that in EBKT group (80%, log-rank test, P=0.38). Significant improvement in estimated glomerular filtration rate (eGFR) was noted in both groups, despite eGFR at 1 year was lower in the SKT group (P<0.01). Proteinuria was common in both groups but subsided gradually during the follow-up time. Complication rates were similar between 2 groups with no vascular thrombosis in the SKT group.

CONCLUSIONS

In conclusion, SKTs from donors weighing ≤10 kg to adult recipients achieves comparable outcomes with EBKTs, which provides evidence to support performing SKTs from donors weighing ≤10 kg in certain donor and recipient scenarios.

Kidney transplantation with allografts from infant donors-Small organs, big value

BACKGROUND

Although infant organ donors remain a rare source of organs for transplantation, technical challenges have resulted in increased rates of complications and inferior graft function. The aim of the present study was to investigate the outcomes of kidneys procured from juvenile and infant donors.

PATIENTS AND METHODS

We evaluated all kidney transplants from deceased donors < 16 years of age performed at our center between 01/2008 and 08/2019. We defined three groups based on quartiles of donor body weight: <13 kg (infant donors), 13-40 kg (juvenile donors), and > 40 kg (standard criteria donors). Clinical characteristics and outcomes were compared between groups.

RESULTS

Ninety-two transplants were included in this study. Out of 92 recipients, there were 32 (34.8%) adult and 60 (65.2%) pediatric patients. All groups demonstrated excellent graft function and survival on both short and long-term follow-up. 1-year, 3-year, and 5-year graft survival rates for the standard criteria donor group were 100%, 95.2%, and 88.4%, respectively, compared with 95.8% for infant and 95% for juvenile donors at all times (P = .79). eGFR at 5 years was 98.9 ± 5.5, 74.1 ± 6.2, and 81.6 ± 6.9 mL/min/1.73 m² for infant, juvenile, and standard criteria donors, respectively (P < .01).

CONCLUSION

Infant donor allografts can be transplanted with excellent long-term outcomes in both pediatric and adult recipients. Implanting them as single allografts onto pediatric candidates allows for the transplantation of two patients. As such, pediatric recipients should be prioritized for these donor organs.