Do we need a different organ allocation system for kidney transplants using donors after circulatory death?

Ranking patients on the kidney transplant waiting list based on fuzzy inference system

Background

Kidney transplantation is the best treatment for people with End-Stage Renal Disease (ESRD). Kidney allocation is the most important challenge in kidney transplantation process. In this study, a Fuzzy Inference System (FIS) was developed to rank the patients based on kidney allocation factors. The main objective was to develop an expert system, which would mimic the expert intuitive thinking and decision-making process in the face of the complexity of kidney allocation.

Methods

In the first stage, kidney allocation factors were identified. Next, Intuitionistic Fuzzy Analytic Hierarchy Process (IF-AHP) has been used to weigh them. The purpose of this stage is to develop a point scoring system for kidney allocation. Fuzzy if-then rules were extracted from the United Network for Organ Sharing (UNOS) dataset by constructing the decision tree, in the second stage. Then, a Multi-Input Single-Output (MISO) Mamdani fuzzy inference system was developed for ranking the patients on the waiting list.

Results

To evaluate the performance of the developed Fuzzy Inference System for Kidney Allocation (FISKA), it was compared with a point scoring system and a filtering system as two common approaches for kidney allocation. The results indicated that FISKA is more acceptable to the experts than the mentioned common methods.

Conclusion

Given the scarcity of donated kidneys and the importance of optimal use of existing kidneys, FISKA can be very useful for improving kidney allocation systems. Countries that decide to change or improve the kidney allocation system can simply use the proposed model. Furthermore, this model is applicable to other organs, including lung, liver, and heart.

Analysis of risk factors for donation after circulatory death kidney transplantation in Japan

Background

In Japan, donations after circulatory death kidney transplantation are widely performed due to legislation delays. The number of donations after brain death kidney transplantations is increasing, but the target remains unmet. We reviewed the outcomes of donation after circulatory death in Japan.

Methods

We analyzed 2923 deceased kidney transplantations (2239: donation after circulatory death (DCD), 684: donation after brain death (DBD)) performed in Japan from 2000 to 2019. The outcomes of the DCD and DBD groups were compared. We examined the risk factors for graft loss in the DCD group.

Results

The 5-year patient survival and death-censored graft survival rates of the DCD group, obtained by propensity score matching, were 93.6% and 95.2%, respectively, which were equivalent to 94.2% and 93.8%, respectively, obtained in the DBD group. Older donors (≥ 50 years) and prolonged cold ischemia time (≥ 12 h) were risk factors for graft loss; in the presence of these, graft survival was lower in the DCD group.

Conclusions

Older donors and prolonged cold ischemia time reduced graft survival in the DCD group. Proper evaluation of donors and careful preparation for transplant surgery are, therefore, essential to ensure good transplant outcomes.

Kidney transplant from controlled donors following circulatory death: Results from the GEODAS-3 multicentre study

INTRODUCTION

Many European countries have transplant programmes with controlled donors after cardiac death (cDCD). Twenty-two centres are part of GEODAS group. We analysed clinical results from a nephrological perspective.

METHODS

Observational, retrospective and multicentre study with systematic inclusion of all kidney transplant recipients from cDCD, following local protocols regarding extraction and immunosuppression.

RESULTS

A total of 335 cDCD donors (mean age 57.2 years) whose deaths were mainly due to cardiovascular events were included. Finally, 566 recipients (mean age 56.5 years; 91.9% first kidney transplant) were analysed with a median of follow-up of 1.9 years. Induction therapy was almost universal (thymoglobulin 67.4%; simulect 32.8%) with maintenance with prednisone-MMF-tacrolimus (91.3%) or combinations with mTOR (6.5%). Mean cold ischaemia time (CIT) was 12.3h. Approximately 3.4% (n=19) of recipients experienced primary non-function, essentially associated with CIT (only CIT ≥ 14 h was associated with primary non-function). Delayed graft function (DGF) was 48.8%. DGF risk factors were CIT ≥ 14 h OR 1.6, previous haemodialysis (vs. peritoneal dialysis) OR 2.1 and donor age OR 1.01 (per year). Twenty-one patients (3.7%) died with a functioning graft, with a recipient and death-censored graft survival at 2-years of 95% and 95.1%, respectively. The estimated glomerular filtration rate at one year of follow-up was 60.9 ml/min.

CONCLUSIONS

CIT is a modifiable factor for improving the incidence of primary non-function in kidney transplant arising from cDCD. cDCD kidney transplant recipients have higher delayed graft function rate, but the same patient and graft survival compared to brain-dead donation in historical references. These results are convincing enough to continue fostering this type of donation.

Impact of Donor Age on Clinical Outcomes of Primary Single Kidney Transplantation From Maastricht Category-III Donors After Circulatory Death

BACKGROUND

Standard-criteria donation after circulatory death (DCD) kidney transplants (KTx) have higher primary nonfunction, delayed graft function (DGF), and rejection rates than age-matched donation after brain death (DBD) but similar graft survival. Data on expanded-criteria DCD are conflicting and many centers remain concerned regarding their use.

METHODS

In this single-center observational study with 5-year follow-up, we analyzed data from 112 primary DCD Maastricht category-III single KTx receiving similar organ preservation and maintenance immunosuppression. Patients were sorted as young DCD (donor <60 years, 72 recipients) or old DCD (donor ≥60 years, 40 recipients). Old DCD outcomes were compared with young DCD and to a DBD control group (old DBD, donor ≥60 years, 40 recipients).

RESULTS

After 5 years, old DCD showed lower patient survival (66% vs 85%; P = 0.014), death-censored graft survival (63% vs 83%; P = 0.001), and Modification of Diet in Renal Disease estimated glomerular filtration rate (34, 27.0-42.0 mL/min per 1.73 m2 vs 45.0, 33.0-58.0 mL/min per 1.73 m2; P = 0.021) than young DCD with higher DGF (70% vs 47.2%; P = 0.029) and graft thrombosis (12.5% vs 1.4%; P = 0.021). Comparison between old DCD and old DBD showed similar 5-year patient survival (66% vs 67%; P = 0.394) and death-censored graft survival (63% vs 69%; P = 0.518) but higher DGF (70% vs 37.5%; P = 0.007) and lower estimated glomerular filtration rate (34, 27.0-42.0 mL/min per 1.73 m2 vs 41, 40.0-42.0 mL/min per 1.73 m2; P = 0.029). Multivariate Cox regression analysis showed that donor 60 years or older (hazard ratio, 3.135; 95% confidence interval, 1.716-5.729; P < 0.001) and induction with anti-IL2-receptor-α monoclonal antibody (hazard ratio, 0.503; 95% confidence interval, 0.269-0.940, P = 0.031 in favor of induction with rabbit antithymocyte globulin) are independent predictors of transplant loss.

CONCLUSIONS

Overall, single KTx from DCD Maastricht category-III donors 60 years or older have inferior outcomes than KTx from donors younger than 60 years. Comparison with age-matched DBD showed similar patient and graft survivals. However, the discrepancy in graft function between DCD and DBD deserves further investigation.

Predicting delayed kidney graft function with gene expression in preimplantation biopsies and first-day posttransplant blood

The purpose of this study was to investigate possible markers for predicting delayed graft function (DGF). To this end we analyzed, in pre-implantation biopsies (PIB) and in first-day post-Tx peripheral blood mononuclear cells (PBMC), the expression of five genes (ACSL4, CUBN, DEFB1, FABP3, GK) through real-time TaqMan PCR assays. These genes were selected from a large scale gene expression study in PIB. DEFB1, FABP3 and GK expression levels in PIB were lower in cases with DGF and, in a multivariate analysis which included these genes and clinical variables, only FABP3 expression remained independently associated with DGF. FABP3 expression lower than -1.32 units of relative expression conferred an odds ratio for DGF of 41.1. Compared to the PBMC of recipients without DGF, recipients with prolonged DGF (pDGF) had lower ACSL4 and higher DEFB1 expression levels. In a multivariate analysis, including PBMC gene expression levels of ACSL4, DEFB1 and TLR4 (data from a previous study with the same patients) and clinical variables, only TLR4 remained independently associated with pDGF. In summary, this study revealed FABP3 expression in PIB as a marker for DGF and disclosed new genes possibly involved in the pathogenesis of DGF.