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

The effect of low donor-to-recipient body weight ratio on graft survival after dual kidney transplantation from pediatric deceased donors

BACKGROUND

Dual kidney transplantation (DKT) from small pediatric donors, either en-bloc or split dual kidney transplantation, contributes to mitigating organ scarcity. This study investigates the prognosis of DKT from pediatric deceased donors, and influencing factors.

METHOD

A retrospective study included recipients who underwent DKT from pediatric donors between 2012 and 2022. Recipients were categorized into low mismatch (BWLM, n = 30) and high mismatch (BWHM, n = 10) groups based on donor-recipient weight ratio of 1:10. Outcome encompassed recipient and graft survival, renal function, and adverse events.

RESULT

Forty recipients were included. The average follow-up period was 54.6 months. The 1, 3, and 5-year patient survival were 97.4%, with no significant differences between en-bloc and split dual kidney transplantation or between BWLM and BWHM groups. The graft survival at 1, 3, and 5 years were 89.9%, the graft survival of BWHM group was lower than BWLM group (70% vs 96.7%, p = 0.039). The average eGFR at 1, 3, and 5 years postoperatively were (78.93 ± 25.23), (83.82 ± 32.4), and (85.92 ± 37.08) mL/min/1.73 m2, respectively. The BWHM group also experienced higher rates of graft-related surgical complications (p = 0.006) and urinary tract surgical complications (p = 0.042).

CONCLUSION

DKT from pediatric donors yields favorable outcomes, with similar graft survival and complication rates across surgical subgroups. However, significant donor-recipient weight mismatch, particularly when the ratio is less than 1:10, may contribute to increased surgical complications and poorer graft survival. Efforts to minimize extreme weight mismatch are recommended to optimize outcomes.

Establishment of a rat model of pediatric-to-adult kidney transplantation to study the early rapid compensatory growth of the grafts

Pediatric donor kidneys show rapid compensatory development in morphology and function after being transplanted into adult recipients. Establishing an animal model that can simulate clinical pediatric-to-adult (P→A) kidney transplantation is important for studying the characteristics and potential mechanisms related to this rapid graft growth. In the P→A group, kidneys harvested from 3- to 4-week-old Sprague-Dawley (SD) rats weighing <50 g were transplanted into adult SD rats (300-400 g). Novel techniques were employed using recipient common iliac vessels for vascular anastomosis and ureter graft drag-in connection to the recipient bladder. As a control group, conventional kidney transplantation was performed between adult SD rats (A→A group). A total of 11 transplants were performed in the P→A group. Eight recipients survived to 28 days without obvious complications and were euthanized for graft harvesting and analysis. Ultrasonography showed that the renal grafts grew significantly faster in the P→A group than in the A→A group during the first 7 days after transplantation, and the size of the renal grafts in the two groups was similar on day 28. Histology revealed significant glomerular enlargement and cell proliferation in the pediatric donor kidneys, with signs of hyperfiltration injury but without podocyte proliferation. Proximal tubular epithelial cells (PTECs) in the P→A group showed significant cell proliferation and hypertrophy. This study has successfully established an animal model in rats with similar characteristics to clinical P→A kidney transplantation, providing a new tool for studying the pathophysiological changes and potential mechanisms of early rapid compensatory growth of the grafts after small pediatric donor kidneys were transplanted into size-mismatched large adult recipients.

Effect of donor body weight on en bloc pediatric kidney transplantation in adults: A systematic review and meta-analysis

BACKGROUND

The shortage of donor grafts for kidney transplantation remains a critical challenge. En bloc kidney transplantation (EBKT) using small deceased pediatric donors has the potential to expand the donor pool. This review aimed to investigate the outcomes of pediatric-donor EBKT in adults compared with standard single kidney transplantation (SKT).

METHODS

Relevant databases, including Ovid, Web of Knowledge, Google Scholar, Wiley, and Embase, were searched for eligible studies. Demographic data and transplant outcomes were extracted from the included studies. The primary outcome was graft survival. A random-effects model was used for the meta-analysis.

RESULTS

Thirteen studies were included. The median 1-year graft survival rates were 83.8 % and 89.2 % for EBKT and SKT, respectively (risk ratio [RR], 0.97; 95 % confidence interval [CI], 0.93-1.01). The median 5-year graft survival rates were 78.7 % and 72.7 % for EBKT and SKT, respectively (RR, 1.05; 95 % CI, 0.93-1.19). For donors with a body weight > 10 kg (EBKT >10 kg) and ≤ 10 kg (EBKT ≤10 kg), the median 1-year graft survival rates were 100.0 % and 90.0 %, respectively (RR, 1.08; 95 % CI, 1.05-1.12). Vascular complications were identified as the primary cause of graft loss.

CONCLUSIONS

Pediatric-donor EBKT in adults is a safe approach with excellent long-term functional outcomes comparable to those of SKT. EBKT represents an effective option to further utilizing pediatric donor kidneys. Outcomes of EBKT vary based on donor body weight. EBKT ≤10 kg was associated with higher short-term graft failure rates despite long-term performance being comparable to EBKT >10 kg.

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.

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.

Comparison of Outcomes of Kidney Transplantation From Extremely Low Body Weight ≤5kg Versus Larger Body Weight Pediatric Donors

Background

Kidney transplantation from donors who weigh ≤5 kg is performed at only a few transplant centers owing to the high complication and low graft survival rates associated with this approach.

Methods

We retrospectively compared the results of kidney transplantation at our center between January 2015 and December 2019 based on the following pediatric donor criteria: donor body weight ≤5 kg (n=32), 5 kg< donor weight ≤20 kg (n=143), and donor weight >20 kg (n=110). We also perform subgroup analysis of kidney transplantation outcomes from ≤5 kg donors, using conventional (dual separate and classic en-bloc KTx)/novel (en-bloc KTx with outflow tract) surgical methods and allocating to adult/pediatric recipients.

Results

The death-censored graft survival rates from extremely low body weight ≤5kg at 1 month, and 1, 3, and 5 years were 90.6%, 80.9%, 77.5%, and 73.9%, respectively, which were significantly lower than that from larger body weight pediatric donors. However, the 3-, and 5-year post-transplantation eGFRs were not significantly different between the pediatric and adult recipient group. The thrombosis (18.8%) and urinary leakage (18.8%) rates were significantly higher in the donor weight ≤5 kg group. Compared with 5 kg< donor weight ≤20 kg group, donor weight ≤5kg group was at elevated risk of graft loss due to thrombosis (OR: 13.4) and acute rejection (OR: 6.7). No significant difference on the outcomes of extremely low body weight donor kidney transplantation was observed between adults and pediatric recipients. Urinary leakage rate is significantly lower in the novel operation (8.7%) than in the conventional operation group (44.4%).

Conclusions

Although the outcomes of donor body weight ≤5kg kidney transplantation is inferior to that from donors with large body weight, it can be improved through technical improvement. Donors with body weight ≤5 kg can be considered as an useful source to expand the donor pool.

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.

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.

Survival Benefit of En Bloc Transplantation of Small Pediatric Kidneys in Children

BACKGROUND

En bloc transplantation of small pediatric kidneys in children may help expand the existing deceased donor pool; however, studies examining the long-term outcomes of en bloc transplantation in children are few.

METHODS

We used the Scientific Registry of Transplant Recipients to identify 149 pediatric en bloc recipients transplanted from October 1, 1987 to December 31, 2017. We used propensity scores to match 148 en bloc with 581 non-en bloc deceased donor recipients (matching variables: transplant age, gender, race, pretransplant dialysis, transplant center, and year). We evaluated patient and graft survival using Kaplan-Meier and Fleming-Harrington weighted log-rank test and examined survival benefit of en bloc transplantation versus remaining on the waiting list using the sequential Cox approach. We divided the study period into three 10-y intervals to assess the effect of era on outcomes.

RESULTS

Compared with non-en bloc recipients, en bloc recipients had lower 1-y graft survival (78.9% versus 88.9%; P = 0.007); however, when stratified by transplant era, lower 1-y survival was only observed in the oldest era (1987-1997). En bloc recipients had superior 10-y patient (89.0% versus 80.4%; P = 0.04) and graft survival (51.6% versus 39.9%; P = 0.04) compared with non-en bloc recipients. After multivariate adjustment, en bloc transplantation was associated with superior patient survival compared with remaining on the waiting list (adjusted hazard ratio: 0.58; 95% confidence interval: 0.36-0.95; P = 0.03).

CONCLUSIONS

En bloc transplantation of small pediatric kidneys in children is associated with superior long-term patient and graft survival. The increased risk of 1-y graft loss among en bloc recipients only appeared in the oldest era.

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.

Transplantation of a single kidney from pediatric donors less than 10 kg to children with poor access to transplantation: a two-year outcome analysis

Background

Access to kidney transplantation by uremic children is very limited due to the lack of donors in many countries. We sought to explore small pediatric kidney donors as a strategy to provide transplant opportunities for uremic children.

Methods

A total of 56 cases of single pediatric kidney transplantation and 26 cases of en bloc kidney transplantation from pediatric donors with body weight (BW) less than 10 kg were performed in two transplant centers in China and the transplant outcomes were retrospectively analyzed.

Results

The 1-year and 2-year death-censored graft survival in the en bloc kidney transplantation (KTx) group was inferior to that in the single KTx group. Subgroup analysis of the single KTx group found that the 1-year and 2-year death-censored graft survival in the group where the donor BW was between 5 and 10 kg was 97.7 and 90.0%, respectively. However, graft survival was significantly decreased when donor BW was ≤5 kg (p < 0.01), mainly because of the higher rate of thrombosis (p = 0.035). In the single KTx group, the graft length was increased from 6.7 cm at day 7 to 10.5 cm at 36 months posttransplant. The estimated glomerular filtration rate increased up to 24 months posttransplant. Delayed graft function and urethral complications were more common in the group with BW was ≤5 kg.

Conclusions

Our study suggests that single kidney transplantation from donors weighing over 5 kg to pediatric recipients is a feasible option for children with poor access to transplantation.

Small Split Pediatric Kidneys to Expand the Donor Pool: An Analysis of Scientific Registry of Transplant Recipients (SRTR) Data

BACKGROUND

Increased use of pediatric deceased donor kidneys could enlarge the deceased donor kidney pool. Kidney transplant outcomes from small pediatric donors were compared with those from ideal kidney (IK) and expanded criteria kidney (ECK) donors to understand the optimal use of pediatric donor kidneys.

METHODS

Kaplan-Meier analyses compared long-term patient and death-censored graft survival of en bloc kidney (EBK) and split kidney (SpK) transplants from small pediatric donors (aged ≤8 y and weight <30 kg) with those from IK and ECK. Posttransplant serum creatinine) was compared among these cohorts. Deceased donor kidney disposition was determined from small pediatric donors with ≥1 organ transplanted.

RESULTS

Patient and death-censored graft survival were similar among recipients of IK, EBK, and SpK transplants, and were superior to those of recipients of ECK. EBK and SpK transplants from donors 5-30 kg had first-year graft loss similar to ECK. Long-term graft survival and serum creatinine with kidneys from SpK donors >10 kg were better than that with ECK donors. About 3901 transplants were performed from 3660 pediatric donors (53% yield).

CONCLUSIONS

Pediatric kidneys can augment the kidney donor pool and should not be considered ECK. If 90% of kidneys from donors (aged ≤8 y and weight <30 kg) with ≥1 organ transplanted been used (as SpK when >10 kg) an additional 159 kidney transplants per year could have been performed. Expanding the use of pediatric kidneys should be further explored by the transplant community.

A Multicenter Clinical Study of Single-Kidney Transplantation vs En Bloc Transplantation with Kidneys from Deceased Pediatric Donors

BACKGROUND

There are still disputes regarding the choice of surgical approach to harvest organs from pediatric donors for organ recipients. The primary goal of this multicenter, retrospective analysis was to compare outcomes between single-kidney transplantation (SKT) and en bloc kidney transplantation (EBKT).

METHODS

Data from donors and recipients aged 4 to 18 months from 3 transplant centers over 5 year were collected to compare postoperative complications and recoveries of renal function between SKT and EBKT and to determine whether there is a difference in the 1-year patient and kidney survival rate between the 2 groups.

RESULTS

Between the SKT and EBKT groups, the incidence of delayed graft function was significantly higher in the SKT group than in the EBKT group (44.1% vs 17.3%, P = .03), and there were no significant differences in other complications (47.0% vs 59.0%, P = .36). Moreover, no significant differences were observed for the overall patient survival rate (P = .08) or the overall graft survival rate (P = .71).

CONCLUSIONS

The short-term effects of SKT make it worthy of consideration. For infants aged 4 to 18 months, SKT can provide good results, alleviating the current tense situation in kidney donation.

Non-immunologic allograft loss in pediatric kidney transplant recipients

Non-immunologic risk factors are a major obstacle to realizing long-term improvements in kidney allograft survival. A standardized approach to assess donor quality has recently been introduced with the new kidney allocation system in the USA. Delayed graft function and surgical complications are important risk factors for both short- and long-term graft loss. Disease recurrence in the allograft remains a major cause of graft loss in those who fail to respond to therapy. Complications of over immunosuppression including opportunistic infections and malignancy continue to limit graft survival. Alternative immunosuppression strategies are under investigation to limit calcineurin inhibitor toxicity. Finally, recent studies have confirmed long-standing observations of the significant negative impact of a high-risk age window in late adolescence and young adulthood on long-term allograft survival.

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.

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

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

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

BACKGROUND

Utilization of kidneys from small pediatric donors (SPDs ≤ 15 kg) is limited. Decisions to split and use the kidneys for 2 recipients remain controversial.

METHODS

Retrospective single-center study aimed primarily at evaluating graft loss within 30 days after transplant using SPD kidneys. Recipients were divided into group A (donor weight < 10 kg, n = 24) and group B (≥ 10  kg, n = 16).

RESULTS

Forty transplants were performed with 100% patient survival. Mean follow-up was 402 days, overall graft survival was 95%, with 91.7% and 100% in groups A and B, respectively (P = .24). Mean recipient-to-donor weight ratio (RTDWR) was higher in group A (10.5 vs 6.3, P < .001). Surgical complications were similar between the groups. These were more common with en bloc compared to single implantation (P = .05), and RTDWR was the main predictor (P = .005). Graft function was similar between the groups; mean 12-month creatinine was 1.2 mg % and eGFR was 58.2 mL/min/1.73 m². Sixteen out of 38 patients developed proteinuria (42%) with no difference among subgroups, although male recipients were at a higher risk (OR = 8.4 [95% CI 1.5-46.1], P = .014); 83% responded to therapy.

CONCLUSION

Utilization and early splitting of SPD kidneys yields favorable graft survival and function irrespective of donor weight and age. Early splitting should be considered.