Renal allograft survival rates in kidneys initially declined for paediatric transplantation

Pediatric kidney transplantation: outcomes with under and over 6-year-old donors

OBJECTIVE

Kidney shortage for pediatric kidney transplantation (PKT) entails the need to use low-weight and age donors, despite the apprehension. The aim of this study was to analyze the pediatric deceased donor kidney transplantations (pDDKT) outcomes in the first year after the procedure, stratified by donor age.

METHOD

Retrospective cohort of pDDKTs carried out between January 2013, and January 2018, at a PKT reference hospital in Southern Brazil. Donors were divided into group 1 (≤ 6 years), and group 2 (> 6 years); the analysis of the outcomes was carried out in the same period.

RESULTS

There were 143 pDDKTs; 51 (35.66%) in group 1; and 92 (64.34%) in group 2. In both groups there were 17 graft losses (11.8%), with vascular thrombosis as the main cause (group 1: 5; group 2: 4). Among the complications, renal artery stenosis (RAS) with indication for angioplasty and stenting was more frequent in group 1 (7.8%; group 2: 2.2%). The 1-year Renal Transplant Recipients' and graft survival did not show significant differences between the groups, (p =  = 0.95). However, the Glomerular Filtration Rate analysis was higher in group 2, reaching, in the 12th month, 79.3 mL/min/1,73m2, compared to 69.7 mL/min/1,73m2 in group 1(p =  = 0.033).

CONCLUSIONS

Small donors can be considered for pDDKTs, as long as there is an expert team to perform the transplantation.

The UK kidney donor risk index poorly predicts long-term transplant survival in paediatric kidney transplant recipients

Background

The UK kidney offering scheme introduced a kidney donor risk index (UK-KDRI) to improve the utility of deceased-donor kidney allocations. The UK-KDRI was derived using adult donor and recipient data. We assessed this in a paediatric cohort from the UK transplant registry.

Methods

We performed Cox survival analysis on first kidney-only deceased brain-dead transplants in paediatric (<18 years) recipients from 2000-2014. The primary outcome was death-censored allograft survival >30 days post-transplant. The main study variable was UK-KDRI derived from seven donor risk-factors, categorised into four groups (D1-low risk, D2, D3 and D4-highest risk). Follow-up ended on 31-December-2021.

Results

319/908 patients experienced transplant loss with rejection as the main cause (55%). The majority of paediatric patients received donors from D1 donors (64%). There was an increase in D2-4 donors during the study period, whilst the level of HLA mismatching improved. The KDRI was not associated with allograft failure. In multi-variate analysis, increasing recipient age [adjusted HR and 95%CI: 1.05(1.03-1.08) per-year, p<0.001], recipient minority ethnic group [1.28(1.01-1.63), p<0.05), dialysis before transplant [1.38(1.04-1.81), p<0.005], donor height [0.99 (0.98-1.00) per centimetre, p<0.05] and level of HLA mismatch [Level 3: 1.92(1.19-3.11); Level 4: 2.40(1.26-4.58) versus Level 1, p<0.01] were associated with worse outcomes. Patients with Level 1 and 2 HLA mismatches (0 DR +0/1 B mismatch) had median graft survival >17 years regardless of UK-KDRI groups. Increasing donor age was marginally associated with worse allograft survival [1.01 (1.00-1.01) per year, p=0.05].

Summary

Adult donor risk scores were not associated with long-term allograft survival in paediatric patients. The level of HLA mismatch had the most profound effect on survival. Risk models based on adult data alone may not have the same validity for paediatric patients and therefore all age-groups should be included in future risk prediction models.

Outcomes of Declined Deceased Donor Kidney Offers That Are Subsequently Implanted: A UK Registry Study

BACKGROUND

Deceased donor kidneys are often declined for ≥1 patients but then implanted into another. Studies are needed to guide transplant clinicians and patients, especially given the increasing age and comorbidity of donors. This study compares outcomes of recipients of transplanted kidneys that were initially declined with outcomes of patients who remained on the waiting list.

METHODS

This UK Transplant Registry study examined named-patient, adult donation after brain death donor single kidney-only offers that were declined for donor- or organ-related reasons (DORRs), in which the kidney was subsequently transplanted from January 1, 2010, to December 31, 2018. Outcomes included graft function and survival of kidneys transplanted following DORR decline, survival and transplant status of patients who had a kidney declined, and intercenter decline rates.

RESULTS

A total of 4722 kidneys declined for DORRs, which eventually resulted in single kidney-only transplants, were examined. One year after the offer decline, 35% of patients for whom the organ was declined remained on the list, 55% received a deceased donor transplant at a median of 174 d after the initial offer decline, and 4% had been removed or died. For patients transplanted following offer decline, there was no significant difference in 5-y graft survival when comparing the outcomes to those recipients who received the declined kidney. There was significant variation in DORR decline rates between UK transplant units (17%-54%).

CONCLUSIONS

This study shows reasonable outcomes of kidneys previously declined for DORRs and supports the utilization of those considered to be of higher risk for carefully selected recipients.

Patient-specific 3D Printing: A Novel Technique for Complex Pediatric Renal Transplantation

OBJECTIVE

The authors investigated a novel application of patient-specific three-dimensional (3D) printing, to enhance preoperative, multidisciplinary planning in complex, living-donor pediatric renal transplantation.

SUMMARY BACKGROUND DATA

For children with end-stage kidney disease, the transplantation of adult-sized, living-donor kidneys into small recipients (<20 kg) with increasingly complex structural anomalies can be difficult. Establishing the operative feasibility in such cases demands a surgical understanding of anatomy to be derived from medical imaging. However, this is hampered by the representation of complex structures in 2D, the inherent interpretive expertise this demands, and the challenge of conveying this appreciation to others.

METHODS

We report the novel use of patient-specific 3D printed models to achieve personalized management for 3 children who underwent living-donor renal transplantation. Each presented a unique surgical challenge that would otherwise prevent preoperative determination of transplantation feasibility. Patient-specific geometries were segmented from imaging data and fabricated using polyjet, 3D printing technology. Models were verified by an expert radiologist and presented during multidisciplinary discussion and surgical simulation.

RESULTS

3D printed models enhanced preoperative deliberation and surgical simulation and allowed on-table exploration of a small child to be avoided. We have critically determined specific clinical indications, technical insights, limitations, and outcomes of this approach. At latest follow-up (>16 mo) all patients remain well with functioning renal allografts.

CONCLUSIONS

We report the new and safe integration of patient-specific 3D printing into complex pediatric renal transplantation. This technique enhances surgical planning and can inform operative feasibility in those cases which would otherwise be uncertain.