Single versus en bloc kidney transplantation from pediatric donors less than or equal to 15 kg. Transplantation. 2008;86:264-268. [PMID: 18645489 DOI: 10.1097/tp.0b013e318177894e]

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.

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.

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.

Outcomes of small pediatric donor kidney transplants according to donor weight

A small pediatric deceased donor (SPD) weight cutoff whether to transplant as en bloc (EB) or single pediatric (SP) kidney is uncertain. Using UNOS/OPTN data (2000-2019), 27 875 SPDs were divided by (i) EB (11.4%) or SP (88.6%) and (ii) donor weight [≤10 (5.4%), >10-15 (8.3%), >15-18 (3.7%), >18-20 (2.9%), and >20 kg (79.7%)]. SP >20 kg and adult deceased donors (grouped by Kidney Donor Profile Index, KDPI, <30, 30-85, and >85) were used as references. The primary outcome was 10-year graft failure. In SP <10 kg, the hazard ratio (HR) for overall graft failure was 1.64 (1.38-2.20) compared with EB <10 kg, and 1.45 (1.18-1.80) compared with SP >20 kg. In SP >10-15 kg, HR was 1.31 (1.12-1.54) compared with EB >10-15 kg, and 1.04 (0.91-1.18) compared with SP >20 kg. In SP >15 kg, the risk was the same as SP >20 kg. Ten-year overall graft survival of SP 12 kg was comparable to SP >20 kg (62% vs. 57%). Ten-year death censored graft failure of SP >10-15 kg (70%) and SP >15-18 kg (70%) was like the adult donors with KDPI 30-85 (67%). In conclusion, we recommend single kidney transplants from SPDs with weight >12 kg to adult recipients in centers with experience in SPD transplants to optimize organ utilization.

Donor-Recipient BSA Matching Is Prognostically Significant in Solitary and En Bloc Kidney Transplantation From Pediatric Circulatory Death Donors

Background.

As the rate of early postoperative complications decline after transplant with pediatric donation after circulatory death (DCD) kidneys, attention has shifted to the long-term consequences of donor–recipient (D-R) size disparity given the pernicious systemic effects of inadequate functional nephron mass.

Methods.

We conducted a retrospective cohort study using Organ Procurement and Transplantation Network data for all adult (aged ≥18 y) recipients of pediatric (aged 0–17 y) DCD kidneys in the United States from January 1, 2004 to March 10, 2020.

Results.

DCD pediatric allografts transplanted between D-R pairs with a body surface area (BSA) ratio of 0.10–0.70 carried an increased risk of all-cause graft failure (relative risk [RR], 1.36; 95% confidence interval [CI], 1.10–1.69) and patient death (RR, 1.32; 95% CI, 1.01–1.73) when compared with pairings with a ratio of >0.91. Conversely, similar graft and patient survivals were demonstrated among the >0.70–0.91 and >0.91 cohorts. Furthermore, we found no difference in death-censored graft survival between all groups. Survival analysis revealed improved 10-y patient survival in recipients of en bloc allografts (P = 0.02) compared with recipients of single kidneys with D-R BSA ratios of 0.10–0.70. A similar survival advantage was demonstrated in recipients of solitary allografts with D-R BSA ratios >0.70 compared with the 0.10–0.70 cohort (P = 0.02).

Conclusions.

Inferior patient survival is likely associated with systemic sequelae of insufficient renal functional capacity in size-disparate DCD kidney recipients, which can be overcome by appropriate BSA matching or en bloc transplantation. We therefore suggest that in DCD kidney transplantation, D-R BSA ratios of 0.10–0.70 serve as criteria for en bloc allocation or alternative recipient selection to optimize the D-R BSA ratio to >0.70.

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.

Overcoming Mismatch Concerns for Adult Recipients of Small Pediatric Deceased Donor Kidneys

BACKGROUND

Kidneys from very young pediatric donors continue to be underutilized. To reduce discard, the Organ Procurement and Transplantation Network (OPTN) policy was recently updated to allow kidneys from donors weighing <18 kg to be recovered en bloc.

METHODS

We reviewed our center's experience with kidney transplantation in adult recipients of <18 kg pediatric donor kidneys to assess renal function outcomes specific to solitary vs en bloc usage.

RESULTS

The majority of <18 kg donors were used en bloc (n = 39, 72.2% vs n = 15, 27.8%). Donor weight (kg) was similar between the 2 groups (12.3 ± 3.2 vs 14.1 ± 2.5, P = .05). Recipient weight was lower in the solitary kidney group (P = .01). Both groups had a similar donor-to-recipient body weight ratio (0.24 ± 0.3 vs 0.18 ± 0.3, P = .51). The solitary kidney group had a lower estimated glomerular filtration rate at 1 (56.9 ± 24.3 vs 81.8 ± 24.8, P = .01) and 2 years (72 ± 18.6 vs 93.7 ± 21.6, P = .03). By 2 years, both groups had an average estimated glomerular filtration rate >60 mL/min. Kidney allograft growth occurred in both groups, with the largest increase occurring the first month posttransplant (11.9%, 18.6%, P < .0001).

CONCLUSION

For pediatric donors weighing <18 kg, improvements in renal function continue beyond the first posttransplant year. Risk for hyperfiltration injury appears low and renal mass-recipient mass matching is useful in guiding decision-making for solitary vs en bloc utilization.

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.

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.

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.

Successful Single-kidney Transplantation in Adult Recipients Using Pediatric Donors Aged 8 to 36 Months: Comparable Outcomes With Those Using Pediatric Donors Aged >3 Years

BACKGROUND

Using pediatric donors for single-kidney transplantation (SKT) can increase the number of possible recipients. However, it is unclear when SKT involving small pediatric donors and adult recipients can safely be performed without compromising graft outcome.

METHODS

From 2013 to 2017, a total of 102 SKTs in adult recipients were performed in our center using pediatric donors aged <12 years. We compared the outcomes from donors aged 8 to 36 months (the small-kidney group [SKG], n = 46) and from donors aged 3 to 12 years (the big-kidney group [BKG], n = 56). The median follow-up time was 30 months in the SKG and 28 months in the BKG.

RESULTS

All patients achieved satisfactory renal function after transplantation, despite the fact that some patients (SKG, 19.6%; BKG, 28.6%) developed delayed graft function. One-year graft survival and death-censored graft survival in the SKG were 89.1% and 100%, respectively, comparable to the results in the BKG (92.9% and 98.2%). One year later, the graft and patient survival rates in both groups remained unchanged. Pulmonary infection was the main cause of death in patients with a functioning graft (SKG, 4 patients; BKG, 2 patients). Proteinuria occurred early in some patients (SKG, 30.4%; BKG, 19.6%) and decreased gradually within the first year posttransplantation.

CONCLUSIONS

SKT from pediatric donors aged 8 to 36 months to selected adult recipients produced excellent intermediate-term outcomes, comparable with those when older pediatric donors were used. This study provides evidence to support a lower age limit for SKT from pediatric donors.

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.

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.

Successful Pediatric Kidney Transplantation Into an Adult Recipient: A Case Report

BACKGROUND

The constant shortage of kidney donors prompts exploration into new strategies of transplantation. One of these strategies is the use of pediatric donors aged up to 5 years whose kidneys can be transplanted into adult recipients, mainly en bloc. This involves retrieving kidneys en bloc with aorta and inferior vena cava and anastomosing them to the recipient's external iliac vessels.

CASE PRESENTATION

In our hospital, kidneys from a 3-year-old child were transplanted to a 30-year-old man. The recipient with end-stage renal failure, due to glomerular nephritis, was dialyzed for 12 years and had 1 failed transplantation with consequent graftectomy. In 2009, kidneys were transplanted to the external iliac artery and vein with reconstruction of the renal vessels. Shortly after transplantation the patient had normal renal measures. Three months later a critical stenosis of 1 renal artery was detected. Angioplasty was performed but technical reasons did not allow for effective dilatation of the vessel. Further, 6 months after kidney transplantation (KTx) nephrotic proteinuria appeared and features of membranous nephropathy were detected in a renal biopsy. The proteinuria subsided after administration of ramipril and losartan. Doppler ultrasound revealed that 1 artery remained 90% stenotic with a peak systolic velocity of 377 cm/sec. Despite reported complications, renal function appeared normal over 7 years of observation.

CONCLUSIONS

A transplantation of 2 pediatric kidneys into an adult recipient has very high efficacy. The survival of both graft and recipient is similar to the results obtained after living donor kidney transplantation.

Transplantation of pediatric renal allografts from donors less than 10 kg

Few transplant programs use kidneys from donors with body weight (BW) < 10 kg. We hypothesized that pediatric en bloc transplants from donors with BW < 10 kg would provide similar transplant outcomes to larger grafts. All pediatric en bloc renal transplants performed at our center between 2001 and 2017 were reviewed (N = 28). Data were stratified by smaller (donor BW < 10 kg; n = 11) or larger donors (BW > 10 kg; n = 17). Renal volume was assessed during follow-up with ultrasound. Demographic characteristics were similar between the 2 groups of recipients. After mean follow-up of 44 months (smaller donors) and 124 months (larger donors), graft and patient outcomes were similar between groups. Serum creatinine at 1, 3, and 5 years was no different between groups. At 1 day posttransplant, mean total renal volume in the smaller donors was 28 ± 9 mm³ vs 45 ± 12 mm³ (P < .01). By 3 weeks, it was 53 ± 19 mm³ (smaller donors) versus 73 ± 19 mm³ (larger donors) (P = NS). Complication rates were similar between both groups with 1 case of venous thrombosis in the smaller group. With experience, outcomes are equivalent to those from larger pediatric donors.

Venous anastomosis by piggyback technique to avoid twisting of the pediatric en bloc kidney grafts

This is the first report of using piggyback technique for the venous anastomosis in two pediatric recipients of small en bloc kidneys, which was found to be effective to avoid twisting of the grafts and vessels. The donors were aged 2 and 3 years with a body weight of 17 and 20 kg. The recipient age was 14 and 16 years with a body weight of 42 and 54 kg. The implantation was done extraperitoneally in the right iliac fossa. The donor's inferior vena cava was anastomosed to the recipient's distal caval vein side-to-side using 6-0 polydioxanone running suture as the piggyback technique, initially dealing with the short vena cava graft in the first case. At the end of the operation, the kidneys were positioned allowing the lateral aspect of each renal unit to face anteriorly as "closing the book." The cold ischemia time was 895 and 820 minutes, respectively. No vascular complication was observed postoperatively. The patients were discharged on POD 16 and POD 21 with an eGFR of 94 and 102 mL/min/1.73 m², respectively. The graft function is stable during the 5- and 7-month follow-up.

Graft Growth and Podocyte Dedifferentiation in Donor-Recipient Size Mismatch Kidney Transplants

Background

Kidney transplantation is the treatment choice for patients with end-stage renal diseases. Because of good long-term outcome, pediatric kidney grafts are also accepted for transplantation in adult recipients despite a significant mismatch in body size and age between donor and recipient. These grafts show a remarkable ability of adaptation to the recipient body and increase in size in a very short period, presumably as an adaptation to hyperfiltration.

Methods

We investigated renal graft growth as well as glomerular proliferation and differentiation markers Kiel-67, paired box gene 2 and Wilms tumor protein (WT1) expression in control biopsies from different transplant constellations: infant donor for infant recipient, infant donor for child recipient, infant donor for adult recipient, child donor for child recipient, child donor for adult recipient, and adult donor for an adult recipient.

Results

We detected a significant increase in kidney graft size after transplantation in all conditions with a body size mismatch, which was most prominent when an infant donated for a child. Podocyte WT1 expression was comparable in different transplant conditions, whereas a significant increase in WT1 expression could be detected in parietal epithelial cells, when a kidney graft from a child was transplanted into an adult. In kidney grafts that were relatively small for the recipients, we could detect reexpression of podocyte paired box gene 2. Moreover, the proliferation marker Kiel-67 was expressed in glomerular cells in grafts that increased in size after transplantation.

Conclusions

Kidney grafts rapidly adapt to the recipient size after transplantation if they are transplanted in a body size mismatch constellation. The increase in transplant size is accompanied by an upregulation of proliferation and dedifferentiation markers in podocytes. The different examined conditions exclude hormonal factors as the key trigger for this growth so that most likely hyperfiltration is the key trigger inducing the rapid growth response.

Influence of Cold Ischemia Time in Kidney Transplants From Small Pediatric Donors

Background

Clinicians may be reluctant to transplant small pediatric kidneys that have prolonged cold ischemia time (CIT) for fear of an additional deleterious effect because pediatric grafts are thought to be more sensitive to ischemia. We aimed to assess the risks associated with transplantation of small pediatric kidneys with prolonged CIT.

Methods

We performed a retrospective cohort study examining US registry data between 1998 and 2013 of adult first-time kidney-only recipients of small pediatric kidneys from donors weighing 10 to 20 kg, stratified by CIT levels of 0 to 18 (n = 1413), 19 to 30 (n = 1116), and longer than 30 (n = 338) hours.

Results

All-cause graft survival by CIT groups at 1-year was 92%, 88%, and 89%, respectively. 1-year risk-adjusted graft survival hazard ratios were significantly higher with CIT of 19 to 30 hours (adjusted hazard ratios, 1.37; 95% confidence interval, 1.04-1.81) and somewhat higher with CIT greater than 30 hours (adjusted hazard ratios, 1.24; 95% confidence interval, 0.82-1.88) relative to recipients with CIT 0 to 18 hours. There was little variation in the effect of CIT on graft survival when restricted to single kidney transplants only and no significant interaction of CIT category and single kidney transplantation (P = 0.93).

Conclusions

Although prolonged CIT is associated with lower early graft survival in small pediatric donor kidney transplants, absolute decreases in 1-year graft survival rates were 3% to 4%.

En bloc kidney transplantation from a 24 month-old donor to an adult recipient: case presentation and literature review

Paediatric kidney transplantation into adult recipients is a well-recognised technique. However, there are different opinions regarding two methods of transplantation. These two opinions are single kidney transplantation (SKT) and en bloc kidney transplantation (EBKT) from donors up to 20 kg. We are reporting the first successful en bloc kidney transplantation from a small, paediatric donor into an adult recipient in our institution and discussing the appropriate recent literature regarding possible concerns using this technique. Despite the fact that paediatric donors are uncommon and surgical experiences are limited, en bloc kidney transplantation can be performed successfully and could be used to expand the donor pool.

Kidney Donor Profile Index Does Not Accurately Predict the Graft Survival of Pediatric Deceased Donor Kidneys

BACKGROUND

The new deceased donor kidney allocation algorithm uses a Kidney Donor Profile Index (KDPI) based on donor characteristics to predict graft survival and divides kidneys into 4 quality groups (ie, KDPI-A, -B, -C, and -D). Pediatric kidneys constitute 10% to 12% of deceased donor kidneys. We hypothesized that KDPI would not accurately predict pediatric donor graft survival and superior predictive models could be created.

METHODS

Scientific Registry of Transplant Recipients data for years 2000 to 2010 for transplants from child (<10 years) and adolescent (10-17 years inclusive) donors into first-time adult recipients were analyzed with graft failure as the principle outcome. Two novel indices, Child Donor Index (CDI) and Adolescent Donor Index (ADI), were developed using stepwise variable deletion to identify significant model covariates in a Cox Regression. Pediatric donor kidneys were then classified into the 4 quality groups based on both KDPI and CDI/ADI scores. The performance of the KDPI, CDI, and ADI models were compared with respect to the 4 quality groups defined by the new allocation system.

RESULTS

The KDPI did not effectively discriminate between quality groups (P > 0.05 for all but 1 comparison) in Kaplan-Meier survival analyses. The CDI and ADI included novel variables (eg, body mass index percentiles) and successfully discriminated between quality groups (P < 0.05 by log rank test). The Net Reclassification Index showed improvement when switching from KDPI to CDI and ADI, with values of 0.09 (P < 0.001) and 0.073 (P < 0.001), respectively.

CONCLUSIONS

The KDPI does not accurately predict pediatric kidney graft survival. Alternative indices can improve allocation efficiency.

Single vs dual (en bloc) kidney transplants from donors ≤ 5 years of age: A single center experience

AIM: To compare outcomes between single and dual en bloc (EB) kidney transplants (KT) from small pediatric donors.

METHODS: Monocentric nonprospective review of KTs from pediatric donors ≤ 5 years of age. Dual EB KT was defined as keeping both donor kidneys attached to the inferior vena cava and aorta, which were then used as venous and arterial conduits for the subsequent transplant into a single recipient. Donor age was less useful than either donor weight or kidney size in decision-making for kidney utilization as kidneys from donors < 8 kg or kidneys < 6 cm in length were not transplanted. Post-transplant management strategies were standardized in all patients.

RESULTS: From 2002-2015, 59 KTs were performed including 34 dual EB and 25 single KTs. Mean age of donors (17 mo vs 38 mo, P < 0.001), mean weight (11.0 kg vs 17.4 kg, P = 0.046) and male donors (50% vs 84%, P = 0.01) were lower in the dual EB compared to the single KT group, respectively. Mean cold ischemia time (21 h), kidney donor profile index (KDPI; 73% vs 62%) and levels of serum creatinine (SCr, 0.37 mg/dL vs 0.49 mg/dL, all P = NS) were comparable in the dual EB and single KT groups, respectively. Actuarial graft and patient survival rates at 5-years follow-up were comparable. There was one case of thrombosis resulting in graft loss in each group. Delayed graft function incidence (12% dual EB vs 20% single KT, P = NS) was slightly lower in dual EB KT recipients. Initial duration of hospital stay (mean 5.4 d vs 5.6 d) and the one-year incidences of acute rejection (6% vs 16%), operative complications (3% vs 4%), and major infection were comparable in the dual EB and single KT groups, respectively (all P = NS). Mean 12 mo SCr and abbreviated MDRD levels were 1.17 mg/dL vs 1.35 mg/dL and 72.5 mL/min per 1.73 m²vs 60.5 mL/min per 1.73 m² (both P = NS) in the dual EB and single KT groups, respectively.

CONCLUSION: By transplanting kidneys from young pediatric donors into adult recipients, one can effectively expand the limited donor pool and achieve excellent medium-term outcomes.

Dual Kidney Transplantation From Pediatric Donors to Adult Recipients

BACKGROUND

The organ shortage is a global problem. A potential approach to expanding the deceased donor pool is to harvest organs from pediatric patients.

METHODS

Seven cases of dual kidney transplantation from pediatric donors to adult recipients were performed between 2012 and 2014 in our center. The proximal end of the donor aorta (AO) was anastomosed to the right common iliac artery or external artery. The proximal end of the donor inferior vena cava (IVC) was anastomosed to the right external iliac vein. Recipients received basiliximab or antithymocyte globulin as induction therapy, followed by tacrolimus, mycophenolate mofetil, and prednisone. Prophylactic anticoagulation was not universal in our study.

RESULTS

During the 21-month study period, both patient and graft survivals were 100%. No patient showed thrombotic complications. Complications included an acute rejection episode in 1 patient, urine leakage in 2, and anticoagulation related hemorrhage in 1. All recipients had excellent graft function with normal serum creatinine ranging from 0.49 to 1.45 mg/dL and estimated glomerular filtration rate ranging from 56.89 to 145.27 mL/min/1.73 m(2).

CONCLUSIONS

Dual kidney transplantation from pediatric donors to adult recipients is a promising way to expand the donor pool. Using the proximal end of the AO/IVC for anastomosis brings satisfactory results.

Optimizing recovery, utilization and transplantation outcomes for kidneys from small, ≤20 kg, pediatric donors

The optimal balance between maximizing the number versus the outcome of transplantation utilizing kidneys from small (≤20 kg) pediatric donors remains unclear, complicated by the choice of single versus en bloc transplantation with their attendant technical risks. Using the Organ Procurement and Transplantation Network (OPTN) database, we examined kidney recovery and utilization patterns, and 1-year transplant outcomes by single kilogram weight strata. Between January 1, 2005 and June 30, 2010, 2352 kidneys from ≤20 kg donors were transplanted into 1531 recipients, 710 single kidney transplants (SKTs) and 821 en bloc kidney transplants (EBKTs). Increased donor weight was associated with higher rates of recovery, transplantation and SKT. Low donor weight (linear p < 0.001; quadratic p = 0.003), SKT versus EBKT (p = 0.008), increased cold ischemia time (p = 0.003), local versus nonlocal donor (p = 0.0044), low versus high volume center (p = 0.003) and the interaction term between center volume and donor weight (p = 0.0024) were associated with graft failure. Notably, lower donor weight exacerbated the negative impact of low center volume but did not worsen the negative impact of SKT on outcomes. Our data show that EBKT offers superior 1-year survival at the expense of accomplishing one rather than two transplants. However, SKTs yield excellent outcomes when performed at experienced centers.

En bloc kidney transplant from an 18-month-old donor to an adult recipient: Case report and literature review

INTRODUCTION

There is an ever-increasing need for organ donations globally. Paediatric kidney transplantation into adult recipients is a well-recognised technique to expand the donor pool. The transplantation can be done either via en bloc kidney transplant (EBKT) or as single kidney transplantation (SKT).

PRESENTATION OF CASE

An EKBT from a 18-month-old (15 kg) male patient was transplanted in a 35-year old, 85 kg male with end stage renal failure (ESRF), secondary to Focal Segmental Glomerulosclerosis (FSGS) on haemodialysis. Post-operative recovery was uneventful. Immuno-suppressant drugs used were tacrolimus, basiliximab and prednisolone. Doppler ultrasound scans performed post-operatively showed normal renal resistive indices in both kidneys. Serum creatinine decreased from 1200 to 170 μmol/L 57 with eGFR improving from 4 to 38 mL/min/1.73 m² at four weeks post-transplant.

DISCUSSION

Given the low incidence of paediatric donors, EBKTs are relatively uncommon and subsequently published series tend to be centre specific with small numbers. The graft survival rates tell us that paediatric kidney donors should not be considered as marginal transplants. The difficulty is in determining when it is more appropriate to perform a paediatric EBKT as opposed to splitting and performing two SKT. Unfortunately there are no widely accepted guidelines to direct clinicians.

CONCLUSION

This case report highlights the first EKBT performed at our institution. The current literature demonstrates that paediatric donors are excellent resources that should be procured whenever available.

Intermediate-term outcome of single kidney grafts from pediatric donors weighing 10-14 kg in adult recipients

BACKGROUND

Kidneys from pediatric donors weighing <10 kg are preferably transplanted en bloc, while kidneys from donors weighing >15 kg can be safely transplanted as single kidneys. However, single kidney transplantation from donors weighing 10-14 kg is controversial and has not been well investigated.

METHODS

We analyzed the outcome of 15 recipients of single kidneys from donors weighing 10-14 kg (study group) with 40 recipients receiving an allograft from ideal deceased donors (control group).

RESULTS

After a follow-up of three yr, death-censored graft survival was 100% in both groups. The calculated creatinine clearance was lower in the study group at six months (53 vs. 71 mL/min; p = 0.01) and similar at 12 months (68 vs. 68 mL/min; p = 0.48), 24 months (81 vs. 70 mL/min; p = 0.58), and 36 months (74 vs. 69 mL/min; p = 0.59). Urinary albumin/creatinine ratios were comparable between the two groups up to two yr. At three yr, urinary albumin/creatinine ratios were higher in the study group than the control group (10.5 vs. 0.9 mg/mmol; p = 0.007). Surveillance biopsies at three and six months post-transplant revealed no evidence for focal segmental glomerulosclerosis in the study group.

CONCLUSIONS

Transplantation of single pediatric kidneys from donors weighing 10-14 kg into adult recipients provides excellent intermediate-term outcomes. Low-grade albuminuria, three yr post-transplant, might indicate late-onset hyperfiltration injury.

Kidney grafts from donors ≤ 5 yr of age: single kidney transplantation for pediatric recipients or en bloc transplantation for adults?

Kidneys from donors ≤5 yr of age represent a controversial issue. The purpose of this study was to compare the transplant outcomes as single and single/en bloc grafts into pediatric and adult KT recipients, respectively. All recipients of kidneys from donors ≤5 yr old transplanted at our institution from 3/2003 to 12/2010 were evaluated, and corresponding data were analyzed. There were 11 pediatric and 14 adult recipients. Median donor age and body weight were 38 months and 14 kg, respectively. PNF, n = 2 and DGF, n = 1 were observed only among adult recipients. Five-yr graft survival was 100% for children and 86% for adults. There were no significant differences in graft and patient survival, PNF, DGF, acute rejection, or postoperative complications among children/single (n = 10), adults/en bloc (n = 10), and adults/single (n = 4) KT. Major complications were documented in six adult recipients and one pediatric recipient after en bloc KT. Pediatric recipients showed significantly higher GFR during the first post-transplant year. Kidneys from donors ≤5 yr of age have at least as good outcomes as when transplanted as single allografts into children. Although the study-volume is small, it seems that children benefit from a pediatric-oriented allocation policy.

Kidney transplantation from small pediatric donors: does recipient body mass index matter?

BACKGROUND

The influence of recipient body mass index (BMI) on pediatric-donor kidney transplant outcomes is unclear. We aimed to determine graft survival and functional outcomes of pediatric-donor kidneys compared with adult kidneys stratified by recipient BMI group.

METHODS

Scientific Registry of Transplant Recipients data for recipients from 1996 to 2010 were reviewed. Donors were categorized by transplant type, pediatric single kidney transplant (SKT, n=3712), en bloc kidney transplant (EBK, n=1517), or adult standard criteria donor (SCD, n=66,741). Recipients were stratified by BMI tertiles (<24, 24-29, and >29 kg/m).

RESULTS

SKT and EBK from donors ≤40 kg conferred similar risks of adjusted death-censored graft survival relative to SCDs regardless of recipient BMI except for EBK transplants in recipients with BMI <24 where the effect was protective (adjusted hazard ratio [aHR] 0.71, 95% confidence interval [CI] 0.56-0.94). SKT from donors ≤20 kg conferred worse death-censored graft survival in recipients with BMI <24 (aHR 1.3, 95% CI 1.0-1.6) and BMI >29 (aHR 1.5, 95% CI 1.1-2.0); however, most of the risk appeared early, and the effect was abrogated with reanalysis conditional on 1-year graft survival. Compared with SCDs, 1-year glomerular filtration rates of SKT from donors ≤20 kg were significantly higher when transplanted into recipients with BMI <24 (P<0.01) and similar in the other BMI groups.

CONCLUSION

Increasing recipient BMI is not a clear risk factor for outcomes or graft function after transplantation with small pediatric-donor kidneys.

Good outcome of kidney transplants in recipients of young donors: a NAPRTCS data analysis

NAPRTCS data were analyzed to assess outcome of TX recipients from YDs (<5 yr) in comparison with IDs (6-35 yr) and ODs (36-55 yr). Of 9854 TX in NAPRTCS (1987-2003), 469 were YD. Patient survival (PS) and graft survival (GS) were compared between DD TX after 1995; 81YD, 1324 ID, and 429 OD and eGFR were compared among functioning grafts (YD 31, ID 439, OD 174) at three yr. PS was comparable in all groups; GS at one, two, and three yr in TX of YD (91.1%, 83.8%, 79.7%), ID (93.5%, 89.7%, 83.6%), and OD (92.2%, 87.2%, 82.4%) was comparable. The eGFR in YD was comparable to ID but better than OD (86.5 vs. 79.7 vs. 67.2 mL/min/1.73 m2, p 0.139 and<0.0003). Primary graft non-function was more frequent in TX from YD than ID and OD (3.7% vs. 0.3 and 0.7%, p=0.004); the incidence of vascular thrombosis was similar. The aforementioned data show that pediatric recipients of YD had equivalent patient and graft survival. Although primary graft non-function was higher, eGFR of functioning grafts was comparable to ID. With further improvements in care, kidneys from YD may present a viable option for transplantation.

Pediatric en bloc kidney transplantation to adult recipients: more than suboptimal?

BACKGROUND

To optimize available organs, kidneys from young donors traditionally believed to be suboptimal are transplanted to adults. The purpose of this study is to compare graft survival (GS) of en bloc kidney (EBK) from young pediatric donors to other deceased donor transplants in adult recipients.

METHODS

We analyzed United Network of Organ Sharing/STAR data on primary deceased donor kidney transplants to adult recipients (1988-2006). EBK (age younger than 5 years, n=1696) was compared with solitary pediatric (SP; age younger than 5 years) kidneys (n=1502), and matched standard adult donors (age 18-59 years, n=9594) and expanded criteria donor (ECD; n=6396). The adjusted GS was obtained using Cox proportional hazard model and hazard ratios were calculated.

RESULTS

EBK had lowest acute rejection rates (6.0%) but similar to standard adult transplants (6.3%), and lower than SP and ECD (9.0% and 8.2%; P<0.0001). Delayed graft function rates were lowest in EBK (17.9%), highest in ECD (34.8%; P<0.0001), and similar among SP and standard adult transplants (24.4% and 24.2%). The estimated glomerular filtration rate (eGFR) was best in EBK and worst in ECD (P<0.0001). The eGFR of EBK and SP transplants continuously improved but the eGFR of standard adult and ECD declined. Graft loss was higher in EBK and SP transplants than adult donor transplants during the first 6 months. Despite the highest thrombosis rates in EBK (5.0%) (SP, 3.3%; standard adult, 1.8%; ECD, 2.0%, P<0.0001), GS of EBK became similar to standard adult donor transplants by 5 years and best at 10 years posttransplant (64.0%) and worst in ECD (39.6%; P<0.0001).

CONCLUSION

EBK had the best long-term outcomes among deceased donor transplants and offer unique options for adult kidney transplant recipients.

Successful en bloc transplantation of pediatric deceased donor kidneys with grade 1 injury

Kidney transplantation from deceased donors is in its infancy in India. Marginal donors are now accepted by many centers for kidney transplantation. We report a case of procurement of en bloc kidneys from a pediatric deceased donor having grade 1 renal injury and transplanted to an adult recipient with a follow up of two years and five months.

Single kidney transplantation from young pediatric donors in the United States

Kidney transplantation (KTX) from small pediatric donors is performed as single or en bloc. Criteria to determine when to split pediatric donor kidneys and transplant as singles are not well established. Data reported to the Scientific Registry of Transplant Recipient for donors <10 yrs from 1995 to 2007 were reviewed (n = 5079). Donors were categorized by weight group by 5 kg increments and solitary (n = 3503) versus en bloc (n = 1576). The primary outcome was overall graft survival. Results were compared as adjusted hazard ratios (aHR) relative to ideal standard criteria donors (SCDs) (defined as age 18-39 without other risk factors), non-ideal SCDs (all other SCDs) and expanded criteria donors (age 50-59 with other risk factors or age >or=60). Single KTX from donors >or= 35 kg conferred a similar risk of graft survival as ideal SCDs. Of donors 10-34 kg, risks of en bloc KTX were similar to ideal and risks of single KTX to non-ideal SCDs; single and en bloc KTXs had 7.9 and 5.2 graft losses per 100 follow-up years, respectively. Single KTX from donors >35 kg are similar to ideal SCDs. Single KTX from donors 10-35 kg are similar to non-ideal SCDs. From a resource perspective, pediatric donors 10-35 kg used as singles offer more cumulative graft years than when used en bloc.

Kidney transplantation and donation in children

It has been shown that kidney transplantation results in superior life expectancy and quality of life compared with dialysis treatment for patients with end-stage renal disease. However, kidney transplantation in children differs in many aspects from adult kidney transplantation. This review focuses on specific issues of surgical care associated with kidney transplantation in children, including timing of transplantation, technical considerations, patient and graft survival, growth retardation and post-transplant malignancy. At the same time, there is a large discrepancy between the number of available donor kidneys and the number of patients on the waiting list for kidney transplantation. There is a general reluctance to use paediatric donor kidneys, because of relatively frequent complications such as graft thrombosis and early graft failure. We review the specific aspects of kidney transplantation from paediatric donors such as the incidence of graft thrombosis, hyperfiltration injury and 'en bloc' transplantation of two kidneys from one donor with an excellent long-term outcome, which is comparable with adult donor kidney transplantation. We also discuss the potential use of paediatric non-heart-beating donor kidneys, from donors whose heart stopped beating with the preservation techniques used.