Strategies for an Expanded Use of Kidneys From Elderly Donors

Potential kidney donors among patients with out-of-hospital cardiac arrest and a termination of resuscitation rule

IMPORTANCE

Uncontrolled donation after circulatory determination of death (uDCD) has been developed and can serve as a source of kidneys for transplantation, especially when considering patients that meet extended criteria donation (ECD).

OBJECTIVE

This study assessed the theorical size and characteristics of the potential pool of kidney transplants from uDCD with standard criteria donation (SCD) and ECD among patients who meet Termination of Resuscitation (TOR) criteria following Out of Hospital Cardiac Arrest (OHCA).

METHODS AND PARTICIPANTS

This study focused on adult patients experiencing unexpected OHCA, who were prospectively enrolled in the Parisian registry from May 16th, 2011, to December 31st, 2020.

RESULTS

During the study period, EMS attempted resuscitation for 19,976 OHCA patients, of which 64.5% (12,890) had no return of spontaneous circulation. Among them, 47.4% (9,461) had TOR criteria, representing no chance of survival, and from them, 8.8% (1,764) met SCD criteria and could be potential organ donors and 33.6% (6,720) met ECD for kidney donors. The mean potential number per year of uDCD candidates with SCD and ECD remain stable respectively around 98 (±10.8) and 672 (±103.8) cases per year. Elderly patients (≥65 y.o.) represented 61.2% (n = 5,763/9,461) of patients who met TOR and 100% (5763/5763) of patients who could have matched both ECD criteria and TOR.

CONCLUSION AND RELEVANCE

Implementing uDCD program including SCD and ECD for kidney transplantation among OHCA cases quickly identified by the TOR, holds significant potential to substantially broaden the pool of organ donors. These programs could offer a viable solution to address the pressing burden of kidney shortage, particularly benefiting elderly recipients who may otherwise face prolonged waiting times and limited access to suitable organs.

Kidney transplants from elderly donors: what we have learned 20 years after the Crystal City consensus criteria meeting

Based on the current projection of the general population and the combined increase in end-stage kidney disease with age, the number of elderly donors and recipients is increasing, raising crucial questions about how to minimize the discard rate of organs from elderly donors and improve graft and patient outcomes. In 2002, extended criteria donors were the focus of a meeting in Crystal City (VA, USA), with a goal of maximizing the use of organs from deceased donors. Since then, extended criteria donors have progressively contributed to a large number of transplanted grafts worldwide, posing specific issues for allocation systems, recipient management, and therapeutic approaches. This review analyzes what we have learned in the last 20 years about extended criteria donor utilization, the promising innovations in immunosuppressive management, and the molecular pathways involved in the aging process, which constitute potential targets for novel therapies.

A Machine Learning-Driven Virtual Biopsy System For Kidney Transplant Patients

In kidney transplantation, day-zero biopsies are used to assess organ quality and discriminate between donor-inherited lesions and those acquired post-transplantation. However, many centers do not perform such biopsies since they are invasive, costly and may delay the transplant procedure. We aim to generate a non-invasive virtual biopsy system using routinely collected donor parameters. Using 14,032 day-zero kidney biopsies from 17 international centers, we develop a virtual biopsy system. 11 basic donor parameters are used to predict four Banff kidney lesions: arteriosclerosis, arteriolar hyalinosis, interstitial fibrosis and tubular atrophy, and the percentage of renal sclerotic glomeruli. Six machine learning models are aggregated into an ensemble model. The virtual biopsy system shows good performance in the internal and external validation sets. We confirm the generalizability of the system in various scenarios. This system could assist physicians in assessing organ quality, optimizing allograft allocation together with discriminating between donor derived and acquired lesions post-transplantation.

Performance of Scores Predicting Adverse Outcomes in Procurement Kidney Biopsies From Deceased Donors With Organs of Lower-Than-Average Quality

Several scores have been devised for providing a prognosis of outcomes after kidney transplantation. This study is a comprehensive test of these scores in a cohort of deceased donors with kidneys of lower-than-average quality and procurement biopsies. In total, 15 scores were tested on a retrospective cohort consisting of 221 donors, 223 procurement biopsies, and 223 recipient records for performance on delayed graft function, graft function, or death-censored graft loss. The best-performing score for DGF was the purely clinical Chapal score (AUC 0.709), followed by the Irish score (AUC 0.684); for graft function, the Nyberg score; and for transplant loss, the Snoeijs score (AUC 0.630) and the Leuven scores (AUCs 0.637 and 0.620). The only score with an acceptable performance was the Chapal score. Its disadvantage is that knowledge of the cold ischemia time is required, which is not known at allocation. None of the other scores performed acceptably. The scores fared better in discarded kidneys than in transplanted kidneys. Our study shows an unmet need for practical prognostic scores useful at the time of a decision about discarding or accepting deceased donor kidneys of lower-than-average quality in the Eurotransplant consortium.

Vigilance Data in Organ Donation and Solid Organ Transplantation in Germany: Six Years of Experience 2016-2022

The reporting of serious adverse events (SAE) and serious adverse reactions (SAR) is an essential part of an effective vigilance and surveillance system (V&S) in organ donation and transplantation. All SAE and SAR reported to the German organ procurement organization (DSO) between 2016 and 2022 were analyzed. In case of a possible transmission of a disease to one or more recipients, an assessment of imputability was done according to the grading system of the US Disease Transmission Advisory Committee (DTAC). 543 SAE and SAR cases were reported to the DSO and analyzed in detail. 53 of the 543 reports (9.8%) were proven or probable (P/P) transmissions of infectious diseases, malignancies or other diseases to 75 recipients. Infections were the most frequently reported P/P disease transmission occurrences (30/53, 57%). In case of disease transmission, the mortality of the recipients was high (17/75, 23%), especially when a malignant disease was transmitted (11/22, 50 %). Donor-Derived disease transmission is a rare event (53/8,519; 0.6 %), but when it occurs can lead to significant morbidity and mortality.

Renal Transplantation in the Elderly: Are They All the Same? A Multicenter, Comorbidity-Based Study

INTRODUCTION

The age for kidney transplantation (KT) is no longer a limitation and several studies have shown benefits in the survival of elderly patients. The aim of this study was to examine the relationship of the baseline Charlson comorbidity index (CCI) score to morbidity and mortality after transplantation.

METHODS

In this multicentric observational retrospective cohort study, we included patients older than 60 years admitted on the waiting list (WL) for deceased donor KT from January 01, 2006, to December 31, 2016. The CCI score was calculated for each patient at inclusion on the WL.

RESULTS

Data for analysis were available of 387 patients. The patients were divided in tertiles of CCI: group 1 (CCI: 1-2) n = 117, group 2 (CCI: 3-4) n = 158, and group 3 (CCI: ≥5) n = 112. Patient survival was significantly different between CCI groups at 1, 3, and 5 years, respectively: 90%, 88%, and 84% for group 1, 88%, 80%, and 72% for group 2, and 87%, 75%, and 63% for group 3 (p < 0.0001). Variables associated with mortality were CCI score (p < 0.0001), HLA mismatch (p = 0.014), length of hospital stay (p < 0.0001), surgical complications (p = 0.048).

CONCLUSION

Individualized strategies to modify these variables may improve patient's morbidity and mortality after KT.

Current Evidence and Future Perspectives to Implement Continuous and End-Ischemic Use of Normothermic and Oxygenated Hypothermic Machine Perfusion in Clinical Practice

The use of high-risk renal grafts for transplantation requires the optimization of pretransplant assessment and preservation reconditioning strategies to decrease the organ discard rate and to improve short- and long-term clinical outcomes. Active oxygenation is increasingly recognized to play a central role in dynamic preservation strategies, independent of preservation temperature, to recondition mitochondria and to restore the cellular energy profile. The oxygen-related decrease in mitochondrial succinate accumulation ameliorates the harmful effects of ischemia-reperfusion injury. The differences between normothermic and hypothermic machine perfusion with regard to organ assessment, preservation, and reconditioning, as well as the logistic and economic implications, are factors to take into consideration for implementation at a local level. Therefore, these different techniques should be considered complementary to the perfusion strategy selected depending on functional intention and resource availability. This review provides an overview of the current clinical evidence of normothermic and oxygenated hypothermic machine perfusion, either as a continuous or end-ischemic preservation strategy, and future perspectives.

Protection From Second Warm Ischemic Injury Using a Thermal Barrier Bag in Kidney Transplantation

Second warm ischemic injury during vascular anastomosis not only adversely affects immediate posttransplant function but also affects long-term patient and graft survival. We developed a pouch-type thermal barrier bag (TBB) composed of a transparent, biocompatible insulation material suitably designed for kidneys and conducted the first-in-human clinical trial.

Methods

A living-donor nephrectomy was performed using a minimum skin incision procedure. After back table preparation, the kidney graft was placed inside the TBB and preserved during vascular anastomosis. The graft surface temperature was measured before and after vascular anastomosis using a noncontact infrared thermometer. After completion of the anastomosis, the TBB was removed from the transplanted kidney before graft reperfusion. Clinical data, including patient characteristics and perioperative variables, were collected. The primary endpoint was safety, which was assessed by evaluating adverse events. The secondary endpoints were the feasibility, tolerability, and efficacy of the TBB in kidney transplant recipients.

Results

Ten living-donor kidney transplant recipients with a median age of 56 y (range, 39-69 y) were enrolled in this study. No serious adverse events related to the TBB were observed. The median second warm ischemic time was 31 (27-39) min, and the median graft surface temperature at the end of anastomosis was 16.1 °C (12.8-18.7 °C).

Conclusions

TBB can maintain transplanted kidneys at a low temperature during vascular anastomosis, which contributes to the functional preservation of transplanted kidneys and stable transplant outcomes.

The New Age of Organ Donation-What Factors Have an Influence on the Attitude of Older People? An Attitudinal Survey in Southeastern Spain

Currently, more than half of all donors are aged over 65 years, and previous studies have shown that this group is less willing to support organ donation. Objective: to analyse the attitude of people aged over 65 years toward organ donation and transplantation (ODT) and to determine how their psychosocial profile affects their attitude. Study population: citizens residing in southeastern Spain older than 65 years of age. A representative sample was obtained, which was stratified by gender and geographical location (n = 420). A validated questionnaire about ODT was used. Statistical analysis: a bivariate analysis was performed using the X2 test and a multivariate analysis. The favourable attitude toward the donation of one’s own organs was 53%. The psychosocial variables affecting attitude were mainly: having discussed ODT with one’s family (p < 0.001) or friends (OR 2.223), acceptance of cremation (OR 2.508), and acceptance of an autopsy (OR 2.578). Citizens aged over 65 tend to have an unfavourable attitude toward the donation of their own organs. The lack of dialogue about ODT in social and family settings, and the attitude to the manipulation of one’s own body after death, are aspects of a respondent’s psychosocial profile, which influence this attitude.

Renal Normothermic Machine Perfusion: The Road Toward Clinical Implementation of a Promising Pretransplant Organ Assessment Tool

The increased utilization of high-risk renal grafts for transplantation requires optimization of pretransplant organ assessment strategies. Current decision-making methods to accept an organ for transplantation lack overall predictive power and always contain an element of subjectivity. Normothermic machine perfusion (NMP) creates near-physiological conditions, which might facilitate a more objective assessment of organ quality before transplantation. NMP is rapidly gaining popularity, with various transplant centers developing their own NMP protocols and renal viability criteria. However, to date, no validated sets of on-pump viability markers exist nor are there unified NMP protocols. This review provides a critical overview of the fundamentals of current renal NMP protocols and proposes a framework to approach further development of ex vivo organ evaluation. We also comment on the potential logistical implications of routine clinical use of NMP, which is a more complex procedure compared with static cold storage or even hypothermic machine perfusion.

Long-Term Results of Kidney Transplantation in the Elderly: Comparison between Different Donor Settings

With scarce organ supply, a selection of suitable elderly candidates for transplant is needed, as well as auditing the long-term outcomes after transplant. We conducted an observational cohort study among our patient cohort >60 years old with a long follow up. (1). Patients and Methods: We used our database to study the results after transplant for 593 patients >60 years old who underwent a transplant between 2000–2017. The outcome was compared between live donor (LD; n = 257) recipients, an old-to-old (OTO, n = 215) group using an extended criteria donor (ECD) kidney, and a young-to-old (YTO, n = 123) group using a standard-criteria donor. The Kaplan−Meir method was used to calculate the patient and graft survival and Cox regression analysis in order to find risk factors associated with death. (2). Results: The 5- and 10-year patient survival was significantly better in the LD group (92.7% and 66.9%) compared with the OTO group (73.3% and 42.8%) and YTO group (70.9% and 40.6%) (p < 0.0001). The 5- and 10-year graft survival rates were 90.3% and 68.5% (LD), 61.7% and 30.9% (OTO), and 64.1% and 39.9%, respectively (YTO group; p < 0.0001 between the LD and the two DD groups). There was no difference in outcome between patients in their 60’s and their 70’s. Factors associated with mortality included: age (HR-1.060), DM (HR-1.773), IHD (HR-1.510), and LD/DD (HR-2.865). (3). Conclusions: Our 17-years of experience seems to justify the rational of an old-to-old allocation policy in the elderly population. Live-donor transplant should be encouraged whenever possible. Each individual decision of elderly candidates for transplant should be based on the patient’s comorbidity and predicted life expectancy.

Hypothermic Machine Perfusion of Kidney Transplant: A Mini-Review

Most kidney grafts are marginal and from deceased donors, which yield worse clinical outcomes. Hypothermic machine perfusion has created a paradigm shift in kidney preservation. This mini-review summarizes the main points of hypothermic machine perfusion of kidney transplants that should be known by any physician and surgeon involved with kidney transplantation. Specifically, this review explains a proposed mechanism of action of hypothermic machine perfusion of kidney transplants. This review also describes the clinical effectiveness of hypothermic machine perfusion and explains how to evaluate and predict graft functionality according to machine parameters and perfusate biomarkers. Finally, treatment options and the most recent studies on oxygenated hypothermic machine perfusion are mentioned.

Kidney transplant outcomes in elderly recipients with controlled donation after circulatory death or donation after brain death donors: a registry cohort study

The number of kidney transplant (KT) procedures with controlled donation after circulatory death (cDCD) donors has exponentially increased in Spain in recent years, with a parallel increase in donor and recipient acceptance criteria. The outcomes of cDCD-KT have been reported to be comparable to those of KT with donation after brain death (DBD) donors. However, studies in elderly recipients have yielded contradictory results. We performed a registry analysis of 852 KT recipients aged ≥65 years (575 in the DBD-KT group, 277 in the cDCD-KT group) in Catalonia, Spain. Clinical outcomes and survival were compared between DBD-KT and cDCD-KT recipients. The donor and recipient ages were similar between the two groups (71.5 ± 8.7 years for donors, 70.8 ± 4.1 years for recipients). Delayed graft function (DGF) was more frequent among cDCD-KT recipients, without a difference in the rate of primary nonfunction. The 3-year patient and death-censored graft survival rates were similar between DBD-KT and cDCD-KT recipients (78.8% vs. 76.4% and 90.3% vs. 86.6%, respectively). In multivariable analysis, previous cardiovascular disease and DGF were independent risk factors for patient death. The type of donation (cDCD vs. DBD) was not an independent risk factor for patient survival or graft loss. cDCD-KT and DBD-KT provide comparable patient and graft survival in elderly recipients.

Deciphering transplant outcomes of expanded kidney allografts donated after controlled circulatory death in the current transplant era. A call for caution

Outcomes of kidney transplantation (KT) after controlled circulatory death (cDCD) with highly expanded criteria donors (ECD) and recipients have not been thoroughly evaluated. We analyzed in a multicenter cohort of 1161 consecutive KT, granular baseline donor and recipient factors predicting transplant outcomes, selected by bootstrapping and Cox proportional hazards, and were validated in a contemporaneous European KT cohort (n = 1585). 74.3% were DBD and 25.7% cDCD-KT. ECD-KT showed the poorest graft survival rates, irrespective of cDCD or DBD (log-rank < 0.001). Besides standard ECD classification, dialysis vintage, older age, and previous cardiovascular recipient events together with low class-II-HLA match, long cold ischemia time and combining a diabetic donor with a cDCD predicted graft loss (C-Index 0.715, 95% CI 0.675-0.755). External validation showed good prediction accuracy (C-Index 0.697, 95%CI 0.643-0.741). Recipient older age, male gender, dialysis vintage, previous cardiovascular events, and receiving a cDCD independently predicted patient death. Benefit/risk assessment of undergoing KT was compared with concurrent waitlisted candidates, and despite the fact that undergoing KT outperformed remaining waitlisted, remarkably high mortality rates were predicted if KT was undertaken under the worst risk-prediction model. Strategies to increase the donor pool, including cDCD transplants with highly expanded donor and recipient candidates, should be performed with caution.

Simply Adding Oxygen during Hypothermic Machine Perfusion to Combat the Negative Effects of Ischemia-Reperfusion Injury: Fundamentals and Current Evidence for Kidneys

The use of high-risk renal grafts for transplantation requires optimization of pretransplant preservation and assessment strategies to improve clinical outcomes as well as to decrease organ discard rate. With oxygenation proposed as a resuscitative measure during hypothermic machine preservation, this review provides a critical overview of the fundamentals of active oxygenation during hypothermic machine perfusion, as well as the current preclinical and clinical evidence and suggests different strategies for clinical implementation.

US deceased kidney transplantation: Estimated GFR, donor age and KDPI association with graft survival

BACKGROUND

Despite a significant shortage of kidneys for transplantation in the US, kidneys from older deceased donors are infrequently transplanted. This is primarily over concern of graft quality and transplant durability.

METHODS

The US national transplant database (2000-2018) was assessed for deceased donor kidney transplant patient and graft survival, graft durability and stratified by donor age (<65 years>), Kidney Donor Profile Index (KDPI) and estimated glomerual filtration rate (GFR) one year post-transplantation (eGFR-1) were calculated.

FINDINGS

Recipients of kidneys transplanted from deceased donors >65 years had a lower eGFR-1, (median 39 ml/min) than recipients of younger donor kidneys (median 54 ml/min). However, death-censored graft survival, stratified by eGFR-1, demonstrated similar survival, irrespective of donor age or KDPI. The durability of kidney survival decreases as the achieved eGFR-1 declines. KDPI has a poor association with eGFR-1 and lesser for graft durability. While recipients of kidneys > 65 years had a higher one year mortality than younger kidney recipients, recipients of kidneys > 65 years and an eGFR-1 <30 ml/min, had a lower survival than an untransplanted waitlist cohort (p<0.001).

INTERPRETATION

The durability of kidney graft survival after transplantation was associated with the amount of kidney function gained through the transplant (eGFR-1) and the rate of graft loss (return to dialysis) was not significantly associated with donor age. 24.9% of recipients of older donor kidneys failed to achieve sufficient eGFR-1 providing a transplant survival benefit. While there is significant benefit from transplanting older kidneys, better decision-making tools are required to avoid transplanting kidneys that provide insufficient renal function.

FUNDING

None.

[Very-old deceased donors in kidney transplantation: How far can we go?]

In order to increase the pool of organ donors, kidney transplantation from very old-donors, notably aged more than 70, is increasing. Compared to the United States, where the use of these grafts does not reach 5%, in France it reaches over 20%. Kidney aging is determined by a progressive glomerusclerosis, interstitial fibrosis, and nephrosclerosis, responsible of a linear decrease of glomerular filtration rate with time. Aging in kidney transplantation goes along also with an increased immunogenicity and risk of ischemia-reperfusion injuries. Hence, the prognosis of these transplantations is worse than those from younger donors, even though it remains better than dialysis. Data is lacking on risk factors of graft loss in this specific population. Hypothermic perfusion machine, pre-implantation kidney biopsy, dual kidney transplantation and immunosuppressive strategies have been evaluated to improve the long-term prognosis of these grafts.

Prediction scores for risk of allograft loss in patients receiving kidney transplants: nil satis nisi optimum

Long-term graft survival is the main concern of kidney transplantation. Some strategies have been tested to predict graft survival using estimated glomerular filtration rate or proteinuria at different time points, histologic assessment, non-invasive biomarkers or even machine-learning methods. However, the 'magical formulae' for allograft survival prediction does not exist yet.

Kidney transplantation outcomes from elderly donors after circulatory death: a comparison with elderly brain-dead donors

Background

The use of kidneys from elderly controlled donation after circulatory death (cDCD) donors has increased significantly in recent years. Concerns about outcomes achieved with these elderly cDCD kidneys have arisen. We aimed to compare outcomes from elderly cDCD kidney transplant recipients (KTrs) and elderly donation after brain death donors (DBDs) in KTrs.

Methods

We conducted a single-centre retrospective study including 87 cDCD-KTrs (46 from donors ≥65 years of age and 41 from <65 years) and 126 DBD-KTrs from donors ≥65 years of age from 2013 through 2017). Young cDCD-KTrs were used as controls. The median follow-up was 27.1 months for all cDCD-KTrs and 29.7 months for DBD-KTrs ≥65 years of age.

Results

Donors >65 years of age represented more than half of our global cDCD cohort (52.9%). KTs from elderly cDCDs had similar rates of delayed graft function, primary non-function and vascular complications compared with young cDCD-KTrs and elderly DBD-KTrs. Short and medium-term graft survival from elderly cDCD kidneys are excellent and are comparable to those from young cDCD and elderly DBD kidneys (90% young cDCD versus 88% elderly cDCD versus 80% elderly DBD at 36 months, P = 0.962 and 0.180, respectively). Although recipients from cDCDs ≥65 years of age showed lower 3-year patient survival (78% versus 87% in elderly DBD-KTrs; P = 0.01), recipient age was the only determinant of patient survival [hazard ratio 1.10 (95% confidence interval 1.02–1.17); P < 0.01], without any influence of donor characteristics.

Conclusions

The use of kidneys from elderly cDCDs is increasing in Spain. Short- and medium-term graft outcomes are similar when comparing kidneys from elderly cDCDs and DBDs. Recipient age is the only determinant of patient survival. Additional studies are needed to assess long-term outcomes.

Treatment options for localised renal cell carcinoma of the transplanted kidney

Currently, there is no consensus among the transplant community about the treatment of renal cell carcinoma (RCC) of the transplanted kidney. Until recently, graftectomy was universally considered the golden standard, regardless of the characteristics of the neoplasm. Due to the encouraging results observed in native kidneys, conservative options such as nephron-sparing surgery (NSS) (enucleation and partial nephrectomy) and ablative therapy (radiofrequency ablation, cryoablation, microwave ablation, high-intensity focused ultrasound, and irreversible electroporation) have been progressively used in carefully selected recipients with early-stage allograft RCC. Available reports show excellent patient survival, optimal oncological outcome, and preserved renal function with acceptable complication rates. Nevertheless, the rarity and the heterogeneity of the disease, the number of options available, and the lack of long-term follow-up data do not allow to adequately define treatment-specific advantages and limitations. The role of active surveillance and immunosuppression management remain also debated. In order to offer a better insight into this difficult topic and to help clinicians choose the best therapy for their patients, we performed and extensive review of the literature. We focused on epidemiology, clinical presentation, diagnostic work up, staging strategies, tumour characteristics, treatment modalities, and follow-up protocols. Our research confirms that both NSS and focal ablation represent a valuable alternative to graftectomy for kidney transplant recipients with American Joint Committee on Cancer stage T1aN0M0 RCC. Data on T1bN0M0 lesions are scarce but suggest extra caution. Properly designed multi-centre prospective clinical trials are warranted.

Relevance of KDPI value and acute rejection on kidney transplant outcomes in recipients with delayed graft function - a retrospective study

Delayed graft function (DGF) is associated with poorer graft survival and higher rate of acute rejection (AR). It is unknown whether this negative influence relies on the increased risk of AR or the DGF itself. The different Kidney Donor Profile Index (KDPI) values may also play a role in this interaction. Retrospective study aimed to evaluate the impact of DGF on graft function and graft survival in a subset of KT recipients (2004-2017). We also analyzed the relationship between KDPI and DGF. The study includes 601 KT, 226 of them (37%) developed DGF. Graft survival was lower in patients with DGF compared with non-DGF patients. Multivariable analysis revealed DGF as risk factor for graft loss, independently of the presence or not of acute rejection. Between DGF patients, we observed poorer graft survival in patients with higher KDPI value (>85%). We observed a trend of a greater impact of KDPI in patients with DGF, although this interaction was not statistically significant. Additionally, we observed poorer 12-month graft function in DGF patients. DGF is related to poorer graft survival independently of the developed acute rejection. This negative impact might be influenced by high KDPI values.

Prognostic value for long-term graft survival of estimated glomerular filtration rate and proteinuria quantified at 3 months after kidney transplantation

Background

The estimated glomerular filtration rate (eGFR) measured at 1 year is the usual benchmark applied in kidney transplantation (KT). However, acting on earlier eGFR values could help in managing KT during the first post-operative year. We aimed to assess the prognostic value for long-term graft survival of the early (3 months) quantification of eGFR and proteinuria following KT.

Methods

The 3-, 6- and 12-month eGFR using the Modified Diet in Renal Disease equation (eGFR_MDRD) was determined and proteinuria was measured in 754 patients who underwent their first KT between 2000 and 2010 (with a mean follow-up of 8.3 years) in our centre. Adjusted associations with graft survival were estimated using a multivariable Cox model. The predictive accuracy was estimated using the C-index and net reclassification index. These same analyses were measured in a multicentre validation cohort of 1936 patients.

Results

Both 3-month eGFR_MDRD and proteinuria were independent predictors of return to dialysis (all P < 0.05) and there was a strong correlation between eGFR at 3 and 12 months (Spearman’s ρ = 0.76). The predictive accuracy of the 3-month eGFR was within a similar range and did not differ significantly from the 12-month eGFR in either the derivation cohort [C-index 62.6 (range 57.2–68.1) versus 66.0 (range 60.1–71.9), P = 0.41] or the validation cohort [C-index 69.3 (range 66.4–72.1) versus 71.7 (range 68.7–74.6), P = 0.25].

Conclusion

The 3-month eGFR was a valuable predictor of the long-term return to dialysis whose predictive accuracy was not significantly less than that of the 12-month eGFR in multicentre cohorts totalling >2500 patients. Three-month outcomes may be useful in randomized controlled trials targeting early therapeutic interventions.

Machine perfusion in kidney transplantation

PURPOSE OF REVIEW

The shortage of kidneys for transplantation has led to an urgent need to efficiently utilize the available cadaveric kidneys. Efficient use of machine perfusion may potentially lead to increased use of marginal kidneys by lowering the incidence of delayed graft function (DGF) and improving graft outcomes.

RECENT FINDINGS

Machine perfusion has had a resurgence in the last 10-15 years over static cold storage (SCS). Hypothermic machine perfusion (HMP), the most commonly utilized type of machine perfusion reduces the rates of DGF when compared with SCS with a trend towards improving the overall graft survival.

SUMMARY

Despite reduction in the rates of DGF by HMP, its effect on long-term renal and patient outcomes is not clearly known. There is limited clinical literature in the use of normothermic machine perfusion (NMP) but a few pilot studies have shown its potential to resuscitate commonly discarded kidneys. In addition to preservation, machine perfusion also allows for various diagnostic and therapeutic interventions during the preservation period to assess and optimize the viability of the procured kidney.

Living Kidney Donor Evaluation

Long-term safety of living kidney donation (LKD), especially for young donors, has become a real matter of concern in the transplant community and may contribute to creating resistance to LKD. In this context, the criteria that govern living donor donations must live up to very demanding standards as well as adjust to this novel reality. In the first part, we review the existing guidelines published after 2010 and critically examine their recommendations to see how they do not necessarily lead to consistent and universal practices in the choice of specific thresholds for a parameter used to accept or reject a living donor candidate. In the second part, we present the emergence of a new paradigm for LKD developed in the 2017 Kidney Disease: Improving Global Outcomes guidelines with the introduction of an integrative risk-based approach. Finally, we focus on predonation renal function evaluation, a criteria that remain central in the selection process, and discuss several issues surrounding the donor candidate's glomerular filtration rate assessment.

Impact of acute kidney injury in elderly versus young deceased donors on post-transplant outcomes: A multicenter cohort study

We investigated the impact of acute kidney injury (AKI) in elderly deceased-donors (DDs) vs. AKI in young DDs on post-transplant clinical outcomes. A total of 709 kidney transplant recipients (KTRs) from 602 DDs at four transplant centers were enrolled. KTRs were divided into young-DDKT and elderly-DDKT groups according to the age of DD of 60 years. Both groups were subdivided into non-AKI-KT and AKI-KT subgroups according to AKI in DDs. We investigated short-term and long-term clinical outcomes of non-AKI-DDKT and AKI-DDKT subgroups within young-DDKT and elderly-DDKT groups. The incidence of DGF in the AKI-DDKT subgroup was higher and the allograft function within 12 months after KT in the AKI-DDKT subgroup was lower than those in the non-AKI-DDKT subgroup in both young-DDKT and elderly-DDKT groups. Death-censored allograft survival rate was significantly lower in the AKI-elderly-DDKT subgroup than that in the non-AKI-elderly-DDKT subgroup, but it did not differ between AKI-young-DDKT and non-AKI-young-DDKT subgroup. In multivariable analysis, AKI-elderly-DDKT was an independent risk factor for allograft failure (hazard ratio: 2.648, 95% CI: 1.170-5.994, p = 0.019) and a significant interaction between AKI and old age in DDs on allograft failure was observed (p = 0.001). AKI in elderly DDs, but not in young DDs, can significantly affect long-term allograft outcomes of KTRs.

Optimization of tacrolimus in kidney transplantation: New pharmacokinetic perspectives

Tacrolimus is the cornerstone of immunosuppressive therapy after kidney transplantation (KT), but its use is complicated by a narrow therapeutic index and high inter- and intra-patient pharmacokinetic variability. There are three available oral formulations of tacrolimus: immediate-release tacrolimus (IR-Tac), extended-release tacrolimus (ER-Tac) and a MeltDose® (LCPT) formulation, the latter favoring a prolonged drug release and increased bioavailability. The time-concentration curves of these formulations are different. Compared with IR-Tac and ER-Tac, LCPT has a relatively flat pharmacokinetic profile with less fluctuation between trough and peak exposures, and a delayed peak concentration. This translates to a more stable delivery of tacrolimus and may alleviate the risk of underexposure and allograft rejection or overexposure and toxicity. The once-daily formulation of both ER-TAC and LCPT may also offer a potential advantage on patient adherence. Fast metabolizers of tacrolimus, the elderly, and human leukocyte antigen-sensitized patients are at risk of poorer outcomes after KT, possibly associated with a different exhibited pharmacokinetics of tacrolimus or different requirements in terms of exposure. Simple, practical strategies are needed to identify patients at risk of suboptimal KT outcomes and those who would benefit from a more proactively personalized approach to tacrolimus treatment. This review aims to increase awareness of the link between the pharmacokinetics of oral tacrolimus formulations and the clinical needs of patients after KT, particularly among those who have clinically significant pharmacokinetic variation of tacrolimus.

Utility and safety of early allograft biopsy in adult deceased donor kidney transplant recipients

INTRODUCTION

Delayed graft function (DGF) is considered a risk factor for rejection after kidney transplantation (KTx). Clinical guidelines recommend weekly allograft biopsy until DGF resolves. However, who may benefit the most from such an aggressive policy and when histology should be evaluated remain debated.

METHODS

We analyzed 223 biopsies in 145 deceased donor KTx treated with basiliximab or anti-thymocyte globulin (rATG) and calcineurin inhibitor-based maintenance. The aim of the study was to assess the utility and safety of biopsies performed within 28 days of transplant. Relationships between transplant characteristics, indication, timing, and biopsy-related outcomes were evaluated.

RESULTS

Main indication for biopsy was DGF (87.8%) followed by lack of improvement in graft function (9.2%), and worsening graft function (3.1%). Acute tubular necrosis was the leading diagnosis (89.8%) whereas rejection was detected in 8.2% specimens. Rejection was more frequent in patients biopsied due to worsening graft function or lack of improvement in graft function than DGF (66.7% vs. 3.5%; P = 0.0075 and 33.3% vs. 3.5%; P = 0.0104, respectively) and in biopsies performed between day 15 and 28 than from day 0 to 14 (31.2% vs. 3.7%; P = 0.0002). Complication rate was 4.1%. Management was affected by the information gained with histology in 12.2% cases (7% considering DGF).

CONCLUSIONS

In low-immunological risk recipients treated with induction and calcineurin inhibitors maintenance, protocol biopsies obtained within 2 weeks of surgery to rule out rejection during DGF do not necessarily offer a favourable balance between risks and benefits. In these patients, a tailored approach may minimize complications thus optimizing results.

Systematic review of ablative therapy for the treatment of renal allograft neoplasms

BACKGROUND

To date, there are no guidelines on the treatment of solid neoplasms in the transplanted kidney. Historically, allograft nephrectomy has been considered the only reasonable option. More recently, nephron-sparing surgery (NSS) and ablative therapy (AT) have been proposed as alternative procedures in selected cases.

AIM

To review outcomes of AT for the treatment of renal allograft tumours.

METHODS

We conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 Checklist. PubMed was searched in March 2019 without time restrictions for all papers reporting on radiofrequency ablation (RFA), cryoablation (CA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), and irreversible electroporation (IRE) of solid tumours of the kidney allograft. Only original manuscripts describing actual cases and edited in English were considered. All relevant articles were accessed in full text. Additional searches included all pertinent references. Selected studies were also assessed for methodological quality using a tool based on a modification of the Newcastle Ottawa scale. Data on recipient characteristics, transplant characteristics, disease characteristics, treatment protocols, and treatment outcomes were extracted and analysed. Given the nature and the quality of the studies available (mostly retrospective case reports and small retrospective uncontrolled case series), a descriptive summary was provided.

RESULTS

Twenty-eight relevant studies were selected describing a total of 100 AT procedures in 92 patients. Recipient age at diagnosis ranged from 21 to 71 years whereas time from transplant to diagnosis ranged from 0.1 to 312 mo. Most of the neoplasms were asymptomatic and diagnosed incidentally during imaging carried out for screening purposes or for other clinical reasons. Preferred diagnostic modality was Doppler-ultrasound scan followed by computed tomography scan, and magnetic resonance imaging. Main tumour types were: papillary renal cell carcinoma (RCC) and clear cell RCC. Maximal tumour diameter ranged from 5 to 55 mm. The vast majority of neoplasms were T1a N0 M0 with only 2 lesions staged T1b N0 M0. Neoplasms were managed by RFA (n = 78), CA (n = 15), MWA (n = 3), HIFU (n = 3), and IRE (n = 1). Overall, 3 episodes of primary treatment failure were reported. A single case of recurrence was identified. Follow-up ranged from 1 to 81 mo. No cancer-related deaths were observed. Complication rate was extremely low (mostly < 10%). Graft function remained stable in the majority of recipients. Due to the limited sample size, no clear benefit of a single procedure over the other ones could be demonstrated.

CONCLUSION

AT for renal allograft neoplasms represents a promising alternative to radical nephrectomy and NSS in carefully selected patients. Properly designed clinical trials are needed to validate this therapeutic approach.

To discard or not to discard: transplantation and the art of scoring

The growing gap between inadequate supply and constantly high demand for kidney transplantation observed in the last two decades led to exploring the possibility of using organs from older donors with an increasing number of comorbidities. The main issue in this scenario is to identify transplantable organs and to allocate them to the most suitable recipients. A great number of clinical investigations proposed several acceptance/allocation criteria to reduce the discard rate of these kidneys and to improve their outcome, including histological features at the time of transplant. Despite the widespread use of several histological scoring systems, there is no consensus on their value in predicting allograft survival and there is established evidence that histological analysis is the most common reason to discard expanded criteria donor kidneys. To overcome this issue, a clinical scoring system, the Kidney Donor Profile Index (KDPI), was developed on the basis of easily accessible donor features. The KDPI score, adopted in the new US allocation procedure, has good reproducibility but presents several limitations, as suggested also in this issue of Clinical Kidney Journal. This observation should stimulate the search for novel scores combining clinical, histological and molecular features in an attempt to improve the decision process.

Outcomes of Deceased Donor Kidney Transplantation Using Expanded Criteria Donor Kidneys Following Pulsatile Preservation

Aim

We compared the outcomes of transplanting expanded criteria donor (ECD) kidneys undergoing machine perfusion (MP) versus cold storage (CS).

Material and methods

Data on all expanded criteria deceased donor kidney transplants performed at the University of Pittsburgh Medical Center from January 2003 through December 2012 were collected from an in-house electronic repository. There were 78 patients in the MP group and 101 patients in the CS group. The majority of the ECD kidneys were imported from other organ procurement organizations: 69 of 73 in the MP group (94.5%, 5 from unknown sources); and 90 of 99 in the CS group (91%), 2 from an unknown source). Most of the patients in the MP group (77 of 78) received a combination of MP and static CS. MP was performed just prior to transplantation in all MP patients. We used descriptive statistics to characterize our sample. We used logistic regression analysis to model the binary outcome of delayed graft function (DGF; i.e., “yes/no”) and Cox (proportional hazard) regression to model time until graft failure. The Kaplan-Meier product-limit method was used to estimate survival curves for graft and patient survival.

Results

A total of 179 transplants were done from ECD donors (MP, 78; CS, 101). The mean static cold storage time was 14 ± 4.1 hours and the mean machine perfusion time was 11.2 ± 6.3 hours in the MP group. The donor creatinine was higher (1.3 ± 0.6 mg/dl vs. 1.2 ± 0.4 mg/dl, p = 0.01) and the cold ischemia time was longer (28.9 ± 10 hours vs. 24 ± 7.9 hours, p = 0.0003) in the MP patients. There were no differences between the two groups in DGF rate (20.8% [MP] vs. 25.8% [CS], p = 0.46), six-year patient survival (74% [MP] vs. 63.2% [CS], p = 0.11), graft survival (64.3% [MP] vs. 51.5% [CS], p = 0.22), and serum creatinine levels (1.5 mg/dl vs. 1.5 mg/dl) on univariate analysis. On unadjusted analysis, MP subjects without DGF had longer graft survival compared to CS subjects with DGF (p < 0.0032) and MP subjects with DGF (p < 0.0005). MP subjects without DGF had longer death-censored graft survival compared to CS subjects with DGF (p < 0.0077) and MP subjects with DGF (p < 0.0016). However, on regression analysis, MP subjects had longer graft survival than CS subjects when DGF was not present. MP subjects without DGF had longer patient survival compared to CS subjects with DGF (p < 0.0289), on unadjusted analysis. MP subjects had a reduced risk of graft failure (hazard ratio [HR], 0.34; 95% confidence interval [CI], 0.17, 0.68) and death-censored graft failure (HR, 0.44; 95% CI, 0.19, 1.00), compared to CS subjects when DGF was not present.

Conclusions

Reduction of DGF rates for imported ECD kidneys is vital to optimize outcomes and increase their utilization. One strategy to decrease DGF rates may be to reduce static CS time during transportation, by utilizing a portable kidney perfusion machine.

Early outcomes of kidney transplantation from elderly donors after circulatory death (GEODAS study)

Background

Spain has dramatically increased the number of controlled circulatory death donors (cDCD). The initial selection criteria for considering cDCD for kidney transplantation (KT) have been expanded progressively, with practically no limits in donor age during the last years. We aimed to analyze the early clinical outcomes using expanded (> 65 years) cDCD in comparison with standard ones.

Methods

Observational multicenter study including 19 transplant centers in Spain. We performed a systematic inclusion in a central database of every KT from expanded cDCD at each participant unit from January-2012 to January-2017. Surgical procedures and immunosuppressive protocols were based on local practices. Data was analyzed in the central office using logistic and Cox regression or competitive-risk models for multivariate analysis. Median time of follow-up was 18.1 months.

Results

561 KT were performed with kidneys from cDCD, 135 from donors older than 65 years. As expected, recipients from older cDCD were also older (65.8 (SD 8.8) vs 53.7 (SD 11.4) years; p < 0.001) and with higher comorbidity. At 1 year, no differences were found amongst older and younger cDCD KT recipients in terms of serum creatinine (1.6 (SD 0.7) vs 1.5 (SD 0.8) mg/dl; p = 0.29). Non-death censored graft survival was inferior, but death-censored graft survival was not different (95.5 vs 98.2% respectively; p = 0.481). They also presented a trend towards higher delayed graft function (55.4 vs 46.7%; p = 0.09) but a similar rate of primary non-function (3.7 vs 3.1%; p = 0.71), and acute rejection (3.0 vs 6.3%; p = 0.135). In the multivariate analysis, in short follow-up, donor age was not related with worse survival or poor kidney function (eGFR < 30 ml/min).

Conclusions

The use of kidneys from expanded cDCD is increasing for older and comorbid patients. Short-term graft outcomes are similar for expanded and standard cDCD, so they constitute a good-enough source of kidneys to improve the options of KT wait-listed patients.

Comparison of nighttime and daytime operation on outcomes of kidney transplant with deceased donors: a retrospective analysis

Background:

Kidney transplant is always emergent operations and frequently need to be performed at nighttime to reduce cold ischemia time (CIT). Previous studies have revealed that fatigue and sleep deprivation can result in adverse consequences of medical procedures. This study aimed to evaluate whether nighttime operation has adverse impact on kidney transplant.

Methods:

A retrospective analysis of recipients accepted kidney transplant from deceased donors in one center from 2014 to 2016 was performed. Daytime transplant was defined as operation started after 8 am or ended before 8 pm and nighttime operation was defined as operation ended after 8 pm or started before 8 am. The incidences of complications such as delayed graft function, acute rejection, surgical complications and nosocomial infections were compared between 2 groups. Student's t-test was used to analyze continuous variables such as serum creatinine (Scr) at 1-year of post-transplant. The Chi-square test was used to analyze categorical variables. Differences in recipients and graft survival were analyzed using Kaplan–Meier methodology and log-rank tests.

Results:

Among the 443 recipients, 233 (52.6%) were classified into the daytime group and the others 210 (47.4%) were in the nighttime group. The 1-year survival rate of recipients was similar for the recipients in the daytime and nighttime groups (95.3% vs. 95.2%, P = 0.981). Although the 1-year graft survival rate in the nighttime group was slightly superior to that in the daytime group, the difference was not significant (92.4% vs. 88.4%, P = 0.164). Furthermore, Scr and incidence of complications were also not significantly different between the 2 groups.

Conclusions:

Our results suggested that operation time of kidney transplant with short CIT has no significant impact on the outcome of kidney transplant. Nighttime operation of kidney transplant with short CIT could be postponed to the following day to alleviate the burden on medical staffs and avoid the potential risk.

Analysis of Kidney Donation and Its Relationship With Graft Failure of the Recipient at 1 Year

INTRODUCTION

Currently, the shortage of organs available for kidney transplantation and a change in donors' and recipients' profiles (elderly, with cardiovascular risk, donors after cardiac death), it is becoming necessary to assess grafts from expanded-criteria donors (ECD) in order to have methods that allow us to predict viability and graft survival.

OBJECTIVE

The aim of this study was to analyze the different methods of renal donor assessment (estimated glomerular filtration rate [eGFR], preimplantation biopsy, and Kidney Donor Profile Index [KDPI] score) as predictors of graft survival and renal function of our recipient at 1 year.

METHODS

We performed a descriptive and retrospective study of 183 deceased donor kidney transplantations performed at our center between 2011 and 2015. We calculated the KDPI scores, donor eGFR was estimated using the Chronic Kidney Disease Epidemiology Collaboration Formula equation, and biopsies were evaluated using Banff classification.

RESULTS

ECDs comprised 59.60%, 93% of donors had an eGFR ≥ 60 mL/min/1.73 m², and 41% presented with a KDPI score ≥ 90%. The most frequent range in the biopsy score was 0-3. The 1-year graft survival rate was 86.90%. Factors that negatively influenced graft survival were donor/recipient age, ECD, KDPI, and cold ischemia time (CIT).

CONCLUSION

Prolonged CIT and KDPI ≥ 90% were donor variables that were related to graft failure at 1 year in our center.

Impact of acute kidney injury in expanded criteria deceased donors on post-transplant clinical outcomes: multicenter cohort study

Background

The problem of organ shortage is an important issue in kidney transplantation, but the effect of kidney donation on AKI is unclear. The aim of this study was to investigate the impact of acute kidney injury (AKI) on post-transplant clinical outcomes for deceased donor kidney transplantation (DDKT) using standard criteria donors (SCDs) versus expanded criteria donors (ECDs).

Methods

Five-hundred nine KT recipients receiving kidneys from 386 deceased donors (DDs) were included from three transplant centers. Recipients were classified into the SCD-KT or ECD-KT group according to corresponding DDs and both groups were divided into the AKI-KT or non-AKI-KT subgroups according to AKI in donor. We compared the clinical outcomes among those four groups and investigated the interaction between AKI in donors and ECD on allograft outcome.

Results

The incidence of delayed allograft function was higher when the donors had AKI within SCD-KT and ECD-KT groups. In allograft biopsies within 3 months, chronic change was more significant in the AKI-ECD-KT subgroup than in the non-AKI-ECD-KT subgroup, but it did not differ between AKI-SCD-KT and non-AKI-SCD-KT group. AKI-ECD-KT showed higher risk for death-censored allograft failure than the other three groups and a significant interaction was observed between AKI in donors and ECD on the allograft outcome.

Conclusions

The presence of AKI in ECDs significantly impacted the long-term allograft outcomes of kidney transplant recipients, but it did not in SCDs.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1225-1) contains supplementary material, which is available to authorized users.

PreImplantation Trial of Histopathology In renal Allografts (PITHIA): a stepped-wedge cluster randomised controlled trial protocol

INTRODUCTION

Most potential kidney transplant donors in the UK are aged over 60 years, yet increasing donor age is associated with poorer graft survival and function. Urgent preimplantation kidney biopsy can identify chronic injury, and may aid selection of better 'quality' kidneys from this group. However, the impact of biopsy on transplant numbers remains unproven. The PreImplantation Trial of Histopathology In renal Allografts (PITHIA) study will assess whether the introduction of a national, 24 hours, digital histopathology service increases the number, and improves outcomes, of kidneys transplanted in the UK from older deceased donors.

METHODS AND ANALYSIS

PITHIA is an open, multicentre, stepped-wedge cluster randomised study, involving all UK adult kidney transplant centres. At 4-monthly intervals, a group of 4-5 randomly selected clusters (transplant centres) will be given access to remote, urgent, digital histopathology (total intervention period, 24 months). The trial has two primary end points: it is powered for an 11% increase in the proportion of primary kidney offers from deceased donors aged over 60 years that are transplanted, and a 6 mL/min increase in the estimated glomerular filtration rate of recipients at 12 months post-transplant. This would equate to an additional 120 kidney transplants performed in the UK annually. Trial outcome data will be collected centrally via the UK Transplant Registry held by NHS Blood and Transplant (NHSBT) and will be analysed using mixed effects models allowing for clustering within centres and adjusting for secular trends. An accompanying economic evaluation will estimate the cost-effectiveness of the service to the National Health Service.

ETHICS AND DISSEMINATION

The study has been given favourable ethical opinion by the Cambridge South Research Ethics Committee and is approved by the Health Research Authority. We will present our findings at key transplant meetings, publish results within 4 years of the trial commencing and support volunteers at renal patient groups to disseminate the trial outcome.

TRIAL REGISTRATION NUMBER

ISRCTN11708741; Pre-results.

Recent Innovations in Kidney Transplants

Current donor pool utilization is unable to meet the high demand for kidney transplants. Donor pool expansion using expanded-criteria donors and dual kidney transplantation are viable options. Advances in diagnosing antibody-mediated rejection and targeting immunosuppression increase long-term transplantation success. Further exploration of minimally invasive surgical techniques, kidney bioengineering, and artificial-implantable renal devices hold promise for the future.

Current opinions in organ allocation

Existing methods of academic publication provide limited opportunity to obtain stakeholder input on issues of broad interest. This article reports the results of an experiment to produce a collaborative, crowdsourced article examining a current controversial issue in transplant medicine (hereby referred to as the "C4 Article"). The editorial team as a whole selected the topic of organ allocation, then divided into six sections, each supported by an individual editorial team. Widely promoted by the American Journal of Transplantation, the C4 Article was open for public comment for 1 month. The nonblinded editorial teams reviewed the contributions daily and interacted with contributors in near-real time to clarify and expand on the content received. Draft summaries of each section were posted and subsequently revised as new contributions were received. One hundred ninety-four individuals viewed the manuscript, and 107 individuals contributed to the manuscript during the submission period. The article engaged the international transplant community in producing a contemporary delineation of issues of agreement and controversy related to organ allocation and identified opportunities for new policy development. This initial experience successfully demonstrated the potential of a crowdsourced academic manuscript to advance a broad-based understanding of a complex issue.

Development and validation of a prognostic model for kidney function 1 year after combined pancreas and kidney transplantation using pre-transplant donor and recipient variables

Purpose

The widening gap between demand and supply of organs for transplantation provides extraordinary challenges for ethical donor organ allocation rules. The transplant community is forced to define favorable recipient/donor combinations for simultaneous kidney-pancreas transplantation. The aim of this study is the development of a prognostic model for the prediction of kidney function 1 year after simultaneous pancreas and kidney transplantation using pre-transplant donor and recipient variables with subsequent internal and external validation.

Methods

Included were patients with end-stage renal failure due to diabetic nephropathy. Multivariable logistic regression modeling was applied for prognostic model design with retrospective data from Hannover Medical School, Germany (01.01.2000–31.12.2011) followed by prospective internal validation (01 Jan. 2012–31 Dec. 2015). Retrospective data from another German transplant center in Kiel was retrieved for external model validation via the initially derived logit link function.

Results

The developed prognostic model is able to predict kidney graft function 1 year after transplantation ≥ KDIGO stage III with high areas under the receiver operating characteristic curve in the development cohort (0.943) as well as the internal (0.807) and external validation cohorts (0.784).

Conclusion

The proposed validated model is a valuable tool to optimize present allocation rules with the goal to prevent transplant futility. It might be used to support donor organ acceptance decisions for individual recipients.

Electronic supplementary material

The online version of this article (10.1007/s00423-018-1712-z) contains supplementary material, which is available to authorized users.

Early Immunosuppressive Exposure of Enteric-Coated-Mycophenolate Sodium Plus Tacrolimus Associated with Acute Rejection in Expanded Criteria Donor Kidney Transplantation

Background:

Immunosuppressive agents are still inefficient in preventing biopsy-proven acute rejection (BPAR) after expanded criteria donor (ECD) kidney transplantation. The aim of this study was to investigate the relationships between early immunosuppressive exposure and the development of BPAR.

Methods:

We performed a retrospective study of 58 recipients of ECD kidney transplantation treated with enteric-coated-mycophenolate sodium, tacrolimus (Tac), and prednisone. The levels of mycophenolic acid-area under the curve (MPA-AUC)_0-12h and Tac C₀ were measured at the 1^st week and the 1^st month posttransplant, respectively. The correlation was assessed by multivariate logistic regression.

Results:

The occurrence rates of BPAR and antibody-mediated rejection were 24.1% and 10.3%, respectively. A low level of MPA-AUC_0-12h at the 1^st week posttransplant was found in BPAR recipients (38.42 ± 8.37 vs. 50.64 ± 13.22, P < 0.01). In addition, the incidence of BPAR was significantly high (P < 0.05) when the MPA-AUC_0-12h level was <30 mg·h^-1·L^-1 at the 1^st week (15.0% vs. 44.4%) or the Tac C₀ was <4 ng/ml at the 1^st month posttransplant (33.3% vs. 21.6%). Multivariable logistic regression analysis showed that the MPA-AUC_0-12h at the 1^st week (OR: 0.842, 95% CI: 0.784-0.903) and the Tac C₀ at the 1^st month (OR: 0.904, 95% CI: 0.822–0.986) had significant inverse correlation with BPAR (P < 0.05).

Conclusions:

Low-level exposure of MPA and Tac C₀ in the early weeks posttransplant reflects an increased acute rejection risk, which suggested that MPA-AUC_0-12h <30 mg·h^-1·L^-1 and Tac C₀ <4 ng/ml should be avoided in the first few weeks after transplantation.

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.