Survival in recipients of marginal cadaveric donor kidneys compared with other recipients and wait-listed transplant candidates

Quantifying the Effect of Consent for High-Kidney Donor Profile Index Deceased Donor Transplants in the United States

Key Points

Nationally, 41% of kidney transplant candidates consented to receive high–Kidney Donor Profile Index (KDPI) donor offers in the United States. There was wide variation in consent proportion for high-KDPI donors on the basis of individual characteristics and transplant centers. Consent for high-KDPI kidneys was associated with 15% higher adjusted rates of deceased donor transplantation.

Background

Despite known benefits of kidney transplantation, including transplantation from donors with increased risk factors, many waitlisted candidates die before transplantation. Consent to receive donor kidneys with lower expected survival (e.g ., Kidney Donor Profile Index [KDPI] >85%) is typically obtained at waitlist placement. The presumed benefit of consent to receive high-KDPI donor kidneys is higher likelihood and timeliness of donor offers for transplantation. However, the specific effect of consent on access to transplantation is unclear. Our aims were to evaluate the characteristics of candidates consenting to high-KDPI donor kidneys and the likelihood of receiving a deceased donor transplant over time on the basis of consent.

Methods

We used national Scientific Registry of Transplant Recipients data between 2015 and 2022 (n =213,364). We evaluated the likelihood of consent using multivariable logistic models and time to deceased donor transplant with cumulative incidence plots accounting for competing risks and multivariable Cox models.

Results

Overall, high-KDPI consent was 41%, which was higher among candidates who were older, were Black or Hispanic, had higher body mass index, had diabetes, had vascular disease, and had 12–48 months prelisting dialysis time, with significant center-level variation. High-KDPI consent was associated with higher rates of deceased donor transplant (adjusted hazard ratio=1.15; 95% confidence interval, 1.13 to 1.17) with no difference in likelihood of deceased donor transplant from donors with KDPI <85%. The effect of high-KDPI consent on higher rates of deceased donor transplantation was higher among candidates older than 60 years and candidates with diabetes and variable on the basis of center characteristics.

Conclusions

There is significant variation of consent for high-KDPI donor kidneys and higher likelihood of transplantation associated with consent.

Interaction between cold ischemia time and Kidney Donor Profile Index on postrenal transplant outcomes

We analyzed whether there is an interaction between the Kidney Donor Profile Index (KDPI) and cold ischemia time (CIT) in recipients of deceased donor kidney transplant (KTs). Adults who underwent KTs in the United States between 2014 and 2020 were included and divided into 3 KDPI groups (≤20%, 21%-85%, >85%) and 4 CIT strata (<12, 12-17.9, 18-23.9, ≥24 hours). Multivariate analyses were used to test the interaction between KDPI and CIT for the following outcomes: primary graft nonfunction (PGNF), delayed graft function (DGF), estimated glomerular filtration rate (eGFR) at 6 and 12 months, patient survival, graft survival, and death-censored graft survival (DCGS). A total of 69,490 recipients were analyzed: 18,241 (26.3%) received a graft with KDPI ≤20%, 46,953 (67.6%) with KDPI 21%-85%, and 4,296 (6.2%) with KDPI >85%. Increasing KDPI and CIT were associated with worse post-KT outcomes. Contrary to our hypothesis, howerver, the interaction between KDPI and CIT was statistically significant only for PGNF and DGF and eGFR at 6 months. Paradoxically, the negative coefficient of the interaction suggested that increasing duration of CIT was more detrimental for low and intermediate-KDPI organs relative to high-KDPI grafts. Conversely, for mortality, graft survival, and DCGS, we found that the interaction between CIT and KDPI was not statistically significant. We conclude that, high KDPI and prolonged CIT are independent risk factors for inferior outcomes after KT. Their interaction, however, is statistically significant only for the short-term outcomes and more pronounced on low and intermediate-KDPI grafts than high-KDPI kidneys.

Latest advances in frailty in kidney transplantation: A narrative review

Frailty is a clinical syndrome that is characterised by decline in multiple systems with associated decreased physiological reserve and ability to respond to stressor events. It is associated with greater healthcare burden. It is common in patients with end-stage renal disease (ESRD). Kidney transplantation is considered the optimal form of renal replacement therapy for suitable patients with ESRD. However, surgery and immunosuppression are physiological stresses that can disproportionately affect frail individuals. Frailty is emerging as a potentially important risk factor in patients waitlisted for kidney transplantation. Most of the published research to date in this area comes from a single transplant centre in the USA. Frailty, as measured using the Physical Frailty Phenotype (FP), is prevalent in waitlisted patients and has been associated with early hospital re-admission, prolonged length of stay, delayed graft function and increased mortality after kidney transplantation. However, although kidney transplantation is a substantial physiological stress to a patient's reserve, by restoring kidney function, kidney transplantation has also been shown to improve a patient's frailty status. The FP is the most studied tool in patients waitlisted for transplantation, but it has not been able to distinguish those whose frailty is improved by kidney transplantation. In summary, there remain significant gaps in knowledge and uncertainties as to how to effectively use existing frailty measures to inform decision-making around kidney transplantation. Further research is needed to address these important gaps in the literature.

Histopathological Features and Role of Allograft Kidney Biopsy Among Recipients With Prolonged Delayed Graft Function: A Review

Delayed graft function (DGF) is an early posttransplant complication predictive of adverse outcomes. This "acute kidney injury of transplantation" is often defined as allograft dysfunction requiring renal replacement within 7 d posttransplantation. DGF is an important area of study because it is emerging with efforts to expand the donor pool and address the supply-demand gap in kidney transplantation. DGF is often caused by severe kidney injury mechanisms because of multiple donors, recipients, and immunologic factors. The role of kidney biopsy, particularly in prolonged DGF, is an ongoing area of research and inquiry for clinicians and researchers alike to better define, manage, and predict outcomes of this early posttransplant event. This review aims to provide an in-depth, comprehensive summary of the literature to date on the histopathology of DGF and the role of kidney transplant biopsies in prolonged DGF.

Clinical relevance of the living kidney donor profile index in Korean kidney transplant recipients

BACKGROUND

The Living Kidney Donor Profile Index (LKDPI) was developed in the United States to predict graft outcomes based on donor characteristics. However, there are significant differences in donor demographics, access to transplantation, proportion of ABO incompatibility, and posttransplant mortality in Asian countries compared with the United States.

METHODS

We evaluated the clinical relevance of the LKDPI score in a Korean kidney transplant cohort by analyzing 1860 patients who underwent kidney transplantation between 2000 and 2019. Patients were divided into three groups according to LKDPI score: <0, 1-19.9, and ≥20.

RESULTS

During a median follow-up of 119 months, 232 recipients (12.5%) experienced death-censored graft loss, and 98 recipients (5.3%) died. High LKDPI scores were significantly associated with increased risk of death-censored graft loss independent of recipient characteristics (LKDPI 1-19.9: HR 1.389, 95% CI 1.036-1.863; LKDPI ≥20: HR 2.121, 95% CI 1.50-2.998). High LKDPI score was also significantly associated with increased risk of biopsy-proven acute rejection and impaired graft renal function. By contrast, overall patient survival rates were comparable among the LKDPI groups.

CONCLUSION

High LKDPI scores were associated with an increased risk of death-censored graft loss, biopsy-proven acute rejection, and impaired graft renal function among a Korean kidney transplant cohort.

Association between Kidney Donor Risk Index, kidney graft function and histological changes in early post-transplant graft biopsy

Background

Proper assessment of donor organ quality is crucial for optimal kidney allocation and best long-term outcomes. The aim of this study was to analyze the association between the Kidney Donor Risk Index (KDRI) and histological parameters in early post-transplant graft biopsy in a Polish cohort of kidney transplant recipients.

Methods

In 418 consecutive kidney transplant recipients, a histological evaluation of very early [at median 11 (9-13) post-transplant day] protocol core needle biopsy was performed and analyzed according to the Banff classification. Subjects were divided into quartiles of the KDRI value. Kidney graft function, patient and graft survival were also analyzed over a median follow-up period of 44 (26-56) months.

Results

There was a significant trend toward greater intensity of chronic histology changes along the KDRI quartiles (χ2 = 20.8; P < .001), including interstitial fibrosis, tubular atrophy, mesangial matrix increase and arteriolar hyalinosis. Stepwise multivariate regression analysis revealed that only higher KDRI value independently increased the severity of chronic graft injury (rpartial = 0.340, P < .001). KDRI values were valuable in the determination of both early and long-term graft function.

Conclusion

The KDRI values correlate with chronic histological changes found in early post-implantation kidney biopsies and can also be helpful in the prediction of graft outcome.

Considerable Variability Among Transplant Nephrologists in Judging Deceased Donor Kidney Offers

Introduction

Transplant clinicians may disagree on whether or not to accept a deceased donor kidney offer. We investigated the interobserver variability between transplant nephrologists regarding organ acceptance and whether the use of a prediction model impacted their decisions.

Methods

We developed an observational online survey with 6 real-life cases of deceased donor kidneys offered to a waitlisted recipient. Per case, nephrologists were asked to estimate the risk of adverse outcome and whether they would accept the offer for this patient, or for a patient of their own choice, and how certain they felt. These questions were repeated after revealing the risk of adverse outcome, calculated by a validated prediction model.

Results

Sixty Dutch nephrologists completed the survey. The intraclass correlation coefficient of their estimated risk of adverse outcome was poor (0.20, 95% confidence interval [CI] 0.08-0.62). Interobserver agreement of the decision on whether or not to accept the kidney offer was also poor (Fleiss kappa 0.13, 95% CI 0.129-0.130). The acceptance rate before and after providing the outcome of the prediction model was significantly influenced in 2 of 6 cases. Acceptance rates varied considerably among transplant centers.

Conclusion

In this study, the estimated risk of adverse outcome and subsequent decision to accept a suboptimal donor kidney varied greatly among transplant nephrologists. The use of a prediction model could influence this decision and may enhance nephrologists' certainty about their decision.

Survival after kidney transplantation compared with ongoing dialysis for people over 70 years of age: A matched-pair analysis

Kidney transplantation offers improved survival and quality of life compared to dialysis for most recipients; however, benefits for elderly patients (>70 years) remain uncertain. Using the Australia and New Zealand Dialysis and Transplant Registry (2009-2019), elderly transplant recipients were matched to a waitlisted dialysis patient by age, cause of end-stage kidney disease, and dialysis duration (paired controls). We censored dialysis patients at the time of transplant. Survival was compared using stratified Cox regression. Elderly transplant recipients (KTRs) (n = 465) were matched to waitlisted pairs. Transplant group mortality initially exceeded dialysis due to excess infection-related deaths (1.9 transplant versus 0.3 dialysis/100 patient-years, P = .03). Beyond month 9, a progressive survival benefit in favor of transplantation was apparent. Over a median follow-up of 1.7 years, mortality was 38% lower for KTRs (95% confidence interval 0.41-0.94, P = .02), and 5-year survival was 80% KTRs vs 53% dialysis (P < .001). Recipients of living and standard criteria donor kidneys acquired immediate survival advantage compared with dialysis, while recipients of expanded criteria donor's kidneys experienced elevated risk of death for the first 17 months. Compared with remaining on dialysis, elderly KTRs incur an increased risk of early posttransplant mortality but thereafter may anticipate progressively superior survival rates.

Impact of suboptimal donor to suboptimal recipient kidney transplant on delayed graft function and outcome

Introduction

The demographics of donor and recipient candidates for kidney transplantation (KT) have substantially changed. Recipients tend to be older and polymorbid and KT to suboptimal recipients is associated with delayed graft function (DGF), prolonged hospitalization, inferior long-term allograft function, and poorer patient survival. In parallel, donors are also older, suffer from several comorbidities, and donations coming from circulatory death (DCD) predominate, which in turn leads to early and late complications. However, it is unclear how donor and recipient risk factors interact.

Methods

In this retrospective cohort study, we assess the impact of a KT from suboptimal donors to suboptimal recipients. We focused on: 1) DGF; 2) hospital stay and number of dialysis days after KT and 3) allograft function at 12 months.

Results and discussion

Among the 369 KT included, the overall DGF rate was 25% (n = 92) and median time from reperfusion to DGF resolution was 7.8 days (IQR: 3.0-13.8 days). Overall, patients received four dialysis sessions (IQR: 2-8). The combination of pre-KT anuria (<200 ml/24 h, 32%) and DCD procurement (14%) was significantly associated with DGF, length of hospital stay, and severe perioperative complications, predominantly in recipients 50 years and older.

Dialysis after kidney transplant failure: how to deal with this daunting task?

The best treatment for patients with end-stage kidney disease is kidney transplantation, which, if successful provides both a reduction in mortality and a better quality of life compared to dialysis. Although there has been significant improvement in short-term outcomes after kidney transplantation, long-term graft survival still remains insufficient. As a result, there has been an increase in the number of individuals who need dialysis again after kidney transplant failure, and increasingly contribute to kidney transplant waiting lists. Starting dialysis after graft failure is a difficult task not only for the patients, but also for the nephrologists and the care team. Furthermore, recommendations for management of dialysis after kidney graft loss are lacking. Aim of this narrative review is to provide a perspective on the role of dialysis in the management of patients with failed kidney allograft. Although numerous studies have reported higher mortality in patients undergoing dialysis following kidney allograft failure, reports are contrasting. A patient-centered, individualized approach should drive the choices of initiating dialysis, dialysis modality, maintenance of immunosuppressive drugs and vascular access.

Value of conventional ultrasound and contrast-enhanced ultrasound for the assessment of renal allograft dysfunction and prognosis

BACKGROUND

Ultrasound (US) is the primary imaging modality for the assessment of transplanted kidneys. This study aims to investigate the ability of conventional US and contrast-enhanced US (CEUS) in assessing renal allograft function and prognosis.

METHODS

A total of 78 consecutive renal allograft recipients were enrolled. Patients were classified as normal allograft function (n = 41) and allograft dysfunction (n = 37) groups. All patients underwent US and parameters were measured. The independent-samples t-test or Mann-Whitney U test, logistic regression analysis, Kaplan-Meier survival plots, and Cox regression analysis were used.

RESULTS

In multivariable analysis, cortical echo intensity (EI) and cortical peak intensity (PI) were determinant US parameters for renal allograft dysfunction (p = .024 and p = .003, respectively). The combination of cortical EI and PI showed an area under the receiver operating characteristic curve (AUROC) of .785 (p < .001). Of 78 patients (median follow-up: 20mo), 16 (20.5%) exhibited composite end points. Cortical PI had a general prediction accuracy with an AUROC of .691, sensitivity of 87.5%, and specificity of 46.8% at the threshold of 22.08 dB in predicting prognosis (p = .019). The combination of estimated-glomerular filtration rate (e-GFR) and PI in predicting prognosis showed an AUROC of .845 with a cut-off value of .836, sensitivity of 84.0%, and specificity of 67.3% (p < .001).

CONCLUSION

This study indicates that cortical EI and PI are useful US parameters for evaluating renal allograft function and e-GFR combined with PI may provide a more accurate predictor of survival.

Outcome of kidney transplantation from senior deceased donors: a single centre study

BACKGROUND

Addressing the current demographic development, the efficacy and safety of kidney transplantations from very senior donors needs to be carefully evaluated. The aim of this study was to analyse patient and graft outcomes of kidney allograft recipients stratified by donor age.

METHODS

We retrospectively investigated n = 491 patients from a prospective, observational renal transplant cohort. Patients with kidneys from very old donors (n = 75, aged >70 years), elderly donors (n = 158, between 60-70 years), and regular donors (n = 258, aged <60 years) were investigated. The primary outcome was death-censored graft survival within the predefined donor age groups.

RESULTS

Overall, n = 57 death-censored graft losses occurred. Graft loss was proportionally highest in the very old donor group (n = 11/75), but this did not reach statistical significance when compared to the elderly (14/158) and regular donor groups (32/258); (p = 0.37). Kaplan-Meier analysis demonstrated that 3-year/5-year death-censored graft survival in the very old donor group was 96%/86% and did not differ from the other age groups (p = 0.44). Median estimated glomerular filtration rate (eGFR), calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula (in ml/min/1.73 m2 of body surface) 12 months post-transplant did not differ between the elderly donor and very old donor groups (p = 0.53). However, patients who received regular donor kidneys had higher median eGFR compared to recipients in both the elderly and very old donor groups (p <0.0001). During follow-up, 31% of patients developed at least one acute rejection episode. Time-to-event analysis demonstrated no difference in occurrence of any acute rejection event across all three groups (p = 0.11).

CONCLUSIONS

This study demonstrates that kidney transplantation from carefully selected very old donors seems a valid option with reasonable short- and mid-term outcomes.

A pre-transplantation risk assessment tool for graft survival in Dutch pediatric kidney recipients

Background

A prediction model for graft survival including donor and recipient characteristics could help clinical decision-making and optimize outcomes. The aim of this study was to develop a risk assessment tool for graft survival based on essential pre-transplantation parameters.

Methods

The data originated from the national Dutch registry (NOTR; Nederlandse OrgaanTransplantatie Registratie). A multivariable binary logistic model was used to predict graft survival, corrected for the transplantation era and time after transplantation. Subsequently, a prediction score was calculated from the β-coefficients. For internal validation, derivation (80%) and validation (20%) cohorts were defined. Model performance was assessed with the area under the curve (AUC) of the receiver operating characteristics curve, Hosmer-Lemeshow test and calibration plots.

Results

In total, 1428 transplantations were performed. Ten-year graft survival was 42% for transplantations before 1990, which has improved to the current value of 92%. Over time, significantly more living and pre-emptive transplantations have been performed and overall donor age has increased (P < .05).The prediction model included 71 829 observations of 554 transplantations between 1990 and 2021. Other variables incorporated in the model were recipient age, re-transplantation, number of human leucocyte antigen (HLA) mismatches and cause of kidney failure. The predictive capacity of this model had AUCs of 0.89, 0.79, 0.76 and 0.74 after 1, 5, 10 and 20 years, respectively (P < .01). Calibration plots showed an excellent fit.

Conclusions

This pediatric pre-transplantation risk assessment tool exhibits good performance for predicting graft survival within the Dutch pediatric population. This model might support decision-making regarding donor selection to optimize graft outcomes.

Trial registration

ClinicalTrials.gov Identifier: NCT05388955.

Outcomes of kidney transplantation from uncontrolled donors after circulatory death vs. expanded-criteria or standard-criteria donors after brain death at an Italian Academic Center: a prospective observational study

BACKGROUND

The use of kidneys from "expanded criteria" donors after brain death (ECD) and uncontrolled donors after circulatory death (uDCD) has been warranted to increase the pool of donors for kidney transplantation (KT). However, there is lack of evidence on the feasibility and safety of KT from such donors in the Italian setting.

METHODS

We queried our prospectively KT database to select patients undergoing KT from deceased donors (uDCDs, ECDs, and standard-criteria donors [SCD] after brain death) from January 2017 to December 2020, comparing the perioperative and mid-term functional outcomes.

RESULTS

Overall, 172 KTs were included. The donor's profile was different among the study groups, while recipients' characteristics were similar expect for median age. Grafts from uDCDs and ECDs had longer median cold ischemia times as compared to grafts from SCDs. The proportion of patients experiencing DGF, the median hospitalization, as well as the overall and major complications rate, were significantly higher among recipients from uDCDs. The proportion of patients needing dialysis at last follow-up was significantly higher among recipients from uDCDs (33.3% vs. 8.5% vs. 5.4%, P<0.001). However, the median eGFR at the last follow-up was lower for recipients from ECDs compared to those from uDCDs and SCDs, respectively (P<0.001).

CONCLUSIONS

While "marginal" donors represent a relevant source of organs, KTs from uDCDs carry higher risks of major surgical complications, DGF, and worse graft survival as compared to KT from both ECDs and SCDs. As such, the use of grafts from uDCDs should be carefully assessed balancing the potential benefits with the risk of primary no function and the subsequent immunological sensitization.

A Machine Learning Prediction Model for Immediate Graft Function After Deceased Donor Kidney Transplantation

BACKGROUND

After kidney transplantation (KTx), the graft can evolve from excellent immediate graft function (IGF) to total absence of function requiring dialysis. Recipients with IGF do not seem to benefit from using machine perfusion, an expensive procedure, in the long term when compared with cold storage. This study proposes to develop a prediction model for IGF in KTx deceased donor patients using machine learning algorithms.

METHODS

Unsensitized recipients who received their first KTx deceased donor between January 1, 2010, and December 31, 2019, were classified according to the conduct of renal function after transplantation. Variables related to the donor, recipient, kidney preservation, and immunology were used. The patients were randomly divided into 2 groups: 70% were assigned to the training and 30% to the test group. Popular machine learning algorithms were used: eXtreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine, Gradient Boosting classifier, Logistic Regression, CatBoost classifier, AdaBoost classifier, and Random Forest classifier. Comparative performance analysis on the test dataset was performed using the results of the AUC values, sensitivity, specificity, positive predictive value, negative predictive value, and F1 score.

RESULTS

Of the 859 patients, 21.7% (n = 186) had IGF. The best predictive performance resulted from the eXtreme Gradient Boosting model (AUC, 0.78; 95% CI, 0.71-0.84; sensitivity, 0.64; specificity, 0.78). Five variables with the highest predictive value were identified.

CONCLUSIONS

Our results indicated the possibility of creating a model for the prediction of IGF, enhancing the selection of patients who would benefit from an expensive treatment, as in the case of machine perfusion preservation.

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.

The Association Between Kidney Donor Profile Index and 1-y Graft Function

The association between Kidney Donor Profile Index (KDPI) and 1-y estimated glomerular filtration rate (eGFR) with long-term kidney graft survival is well known. Yet, the association between KDPI and 1-y eGFR remains uncertain considering the several concurrent competing risk factors.

Methods

This single-center, retrospective cohort study analyzed data from 3059 consecutive deceased donor kidney transplant recipients with a 1-y follow-up from January 2013 to December 2017. The aim was to determine the association between the KDPI strata (0%-35%, 36%-50%, 51%-85%, 86%-100%) and 1-y eGFR estimated by the CKD-EPI equation.

Results

The incidence of delayed graft function (50.6% versus 59.3% versus 62.7% versus 62.0%; P < 0.001) and cytomegalovirus infection (36.7% versus 36.6% versus 43.3% versus 57.8%; P < 0.001) increased with increasing KDPI strata but not biopsy-proven acute rejection (9.1% versus 9.8% versus 8.4% versus 9.1%; P = 0.736). The median 1-y eGFR decreased with increasing KDPI strata (64.8 versus 53.5 versus 46.9 versus 39.1 mL/min/1.73 m²; P < 0.001). In the Cox regression, the higher the KDPI was, the lower the probability of a lower 1-y eGFR was. Assuming the 0%-35% strata as the reference, the likelihood of eGFR <50 mL/min/1.73 m² was increased by 76.6% (hazard ratio [HR] = 1.767, 95% confidence interval [CI] = 1.406-2.220), 2.24- and 2.87-fold higher for KDPI higher >35%-50% (HR = 2.239, 95% CI = 1.862-2.691), and >51%-85% (HR = 2.871, 95% CI = 2.361-3.491), respectively. Other variables associated with a lower graft function were donor sex (HR male versus female = 0.896, 95% CI = 0.813-0.989) and cold ischemia time (HR for each hour = 1.011, 95% CI = 1.004-1.019). This association was sustained after the Poisson mediation analysis, including delayed graft function, cytomegalovirus, and acute rejection as mediators.

Conclusions

In this cohort of deceased donor kidney recipients, KDPI, and cold ischemia time were the major independent risk factors associated with lower 1-y kidney function.

Kidney transplantation from elderly donors (> 70 years): a systematic review

PURPOSE

The incidence of kidney transplants from elderly donors over 70 years of age has increased significantly over the past 10 years to reach 20% of available kidney graft in some European countries. However, there is little data available on the outcomes of transplants from these donors. We performed a systematic review to evaluate the outcomes of transplantation from donors over 70 years of age.

METHODS

A systematic review was performed according to preferred reporting items for systematic reviews and meta-analyses. Medline, Embase, and Cochrane databases were searched to identify all studies reporting outcomes on kidney transplants from donors over 70 years. Due to the heterogeneity of the studies, a meta-analysis could not be performed.

RESULTS

A total of 29,765 patients in 27 studies were included. The mean donors age was 74.79 years, and proportion of kidney graft from women was 53.54%. The estimated 1- and 5-year kidney death-censored graft survivals from donors > 70 years old were, respectively, 85.95 and 80.27%, and the patient survivals were 90.88 and 71.29%. The occurrence of delayed graft function was 41.75%, and primary non-function was 4.67%. Estimated graft function at 1 and 5 years was 36 and 38 mL/min/1.73 m². Paucity data were available on post-operative complications.

CONCLUSIONS

Elderly donors appear to be a reliable source of grafts. However, these transplants are associated with a high rate of delayed graft function without repercussion on long-term graft survival. Allocation strategy to elderly recipients is the main factor of decreased recipient survival.

The Importance Of Avoiding Time-Dependent Bias When Testing The Prognostic Value Of An Intervening Event - Two Acute Cellular Rejection Examples In Intestinal Transplantation

In testing the prognostic value of the occurrence of an intervening event (clinical event that occurs post-transplant), 3 proper statistical methodologies for testing its prognostic value exist (time dependent covariate, landmark, and semi-Markov modelling methods). However, time-dependent bias has appeared in many clinical reports, whereby the intervening event is statistically treated as a baseline variable (as if it occurred at transplant). Using a single-center cohort of 445 intestinal transplant cases to test the prognostic value of 1^st acute cellular rejection (ACR) and severe (grade of) ACR on the hazard rate of developing graft loss, we demonstrate how the inclusion of such time-dependent bias can lead to severe underestimation of the true hazard ratio (HR). The (statistically more powerful) time dependent covariate method in Cox's multivariable model yielded significantly unfavorable effects of 1^st ACR (P<.0001; HR=2.492) and severe ACR (P<.0001; HR=4.531). In contrast, when using the time-dependent biased approach, multivariable analysis yielded an incorrect conclusion for the prognostic value of 1^st ACR (P=.31, HR=0.877, 35.2% of 2.492) and a much smaller estimated effect of severe ACR (P=.0008; HR=1.589; 35.1% of 4.531). In conclusion, this study demonstrates the importance of avoiding time-dependent bias when testing the prognostic value of an intervening event.

Long-term outcomes of kidney transplantation from deceased donors with terminal acute kidney injury: Single center experience and literature review

INTRODUCTION

Long-term outcomes of kidney transplantation from deceased donors (DDKTs) with terminal acute kidney injury (AKI) are not well defined.

METHODS

Single center retrospective review of DDKTs from 1/31/07-12/31/19. AKI kidneys were defined by a doubling of the donor's admission serum creatinine (SCr) level AND a terminal SCr ≥2.0 mg/dl.

RESULTS

A total of 188 AKI DDKTs were performed, including 154 from brain-dead standard criteria donors (SCD). Mean donor age was 36 years and mean Kidney Donor Profile Index was 50%; mean admission and terminal SCr levels were 1.3 and 3.1 mg/dl, respectively. With a mean follow-up of 94 months (median 89 months), overall patient (both 71.3%) and graft survival (54% AKI vs. 57% non-AKI) rates were comparable to concurrent DDKTs from brain-dead non-AKI SCDs (n = 769). Delayed graft function (DGF) was higher in AKI kidney recipients (47% vs. 20% non-AKI DDKTs, p < .0001). DGF was associated with lower graft survival in recipients of both AKI and non-AKI SCD kidneys but the impact was earlier and more pronounced in non-AKI recipients.

CONCLUSIONS

Despite having more than twice the incidence of DGF, kidneys from deceased donors with terminal AKI have long-term outcomes comparable to non-AKI SCD kidneys and represent a safe and effective method to expand the donor pool.

Delayed graft function: current status and future directions

PURPOSE OF REVIEW

Delayed graft function is a common early posttransplant event predictive of adverse outcomes including hospital readmission, impaired long-term graft function, and decreased graft and patient survival. The purpose of this review is to summarize recent literature describing delayed graft function in hopes of better understanding and managing this condition.

RECENT FINDINGS

Recent research efforts have been garnered towards risk factor modification, prevention, and earlier detection of delayed graft function. In this review, we aim to summarize current innovative approaches and future directions.

SUMMARY

Delayed graft function portends worse graft and patient outcomes. Continued research to prevent, and detect early perturbations in allograft function, and more optimally manage this disease will hopefully improve graft function, along with graft/patient survival.

Reexamining the Impact of Insurance Type on Kidney Transplant Waitlist Status and Posttransplantation Outcomes in the United States After Implementation of the Affordable Care Act

Insurance type, a marker of socioeconomic status, has been associated with poor access to kidney transplant (KT) and worse KT outcomes before the implementation of the Affordable Care Act (ACA) and the revised Kidney Allocation System (KAS). In this study, we assessed if insurance type remained a risk marker for worse waitlist and transplant outcomes after ACA and KAS.

Methods

Using Scientific Registry of Transplant Recipients data, we assessed insurance type of waitlisted candidates pre- (2008-2014) versus post- (2014-2021) KAS/ACA using chi-square tests. Next, we performed a competing risk analysis to study the effect of private versus public (Medicare, Medicaid, or government-sponsored) insurance on waitlist outcomes and a Cox survival analysis to study posttransplant outcomes while controlling for candidate, and recipient and donor variables, respectively.

Results

The proportion of overall KT candidates insured by Medicaid increased from pre-KAS/ACA to post-KAS/ACA (from 12 667 [7.3%] to 21 768 [8.8%], P < 0.0001). However, KT candidates with public insurance were more likely to have died or become too sick for KT (subdistribution hazard ratio [SHR] = 1.33, confidence interval [CI], 1.30-1.36) or to receive a deceased donor KT (SHR = 1.57, CI, 1.54-1.60) but less likely to receive a living donor KT (SHR = 0.87, CI, 0.85-0.89). Post-KT, KT recipients with public insurance had greater risk of mortality (relative risks = 1.22, CI, 1.15-1.31) and allograft failure (relative risks = 1.10, CI, 1.03-1.29).

Conclusions

Although the implementation of ACA marginally increased the proportion of waitlisted candidates with Medicaid, publicly insured KT candidates remained at greater risk of being removed from the waitlist, had lower probability of living donor kidney transplantation, and had greater probability of dying post-KT and allograft failure. Concerted efforts to address factors contributing to these inequities in future studies are needed, with the goal of achieving equity in KT for all.

Comparison of Survival in Recipients of Marginal and Standard Cadaveric Donor Kidneys

BACKGROUND

Renal transplantation is the main treatment for end-stage renal disease and has rapidly increased in number over the past 3 decades, leading to an increasing need for organs. The disparity between organ access and the number of patients on the waiting list has led transplant surgeons to use marginal cadaveric donors. As a consequence, the concept of "marginal cadaveric kidney donor" has been developed.

METHODS

We retrospectively evaluated 120 patients who received kidneys from cadaveric donors between September 2009 and August 2021. The donors were divided into standard and marginal cadaveric donors, and their age, sex, cause of death, criteria of acceptance as marginal donors, and Kidney Donor Profile Index (KDPI) were recorded RESULTS: The donors included 69 men and 51 women, with a mean age of 52.9 ± 16.8 years. There were 52 standard donors and 68 marginal donors. Graft and donor survival were compared based on the KDPI values of the donors, and were respectively found to be higher in those with a KDPI of 0 to 60 than in those with a KDPI of 81 to 100 (P = .011 and .039, respectively). There was no significant difference between those with a KDPI of 61 to 80 and the other groups.

CONCLUSIONS

Expanded criteria donor organs, which offer greater survival benefits than hemodialysis, can be used safely to meet the increasing need for donors. Expanded criteria donor organs should thus be considered a valuable alternative in this patient group.

Kidney utility and futility

Changes in kidney allocation coupled with the COVID-19 pandemic have placed tremendous strain on current systems of organ distribution and logistics. Although the number of deceased donors continues to rise annually in the United States, the proportion of marginal deceased donors (MDDs) is disproportionately growing. Cold ischemia times and kidney discard rates are rising in part related to inadequate planning, resources, and shortages. Complexity in kidney allocation and distribution has contributed to this dilemma. Logistical issues and the ability to reperfuse the kidney within acceptable time constraints increasingly determine clinical decision-making for organ acceptance. We have a good understanding of the phenotype of "hard to place" MDD kidneys, yet continue to promote a "one size fits all" approach to organ allocation. Allocation and transportation systems need to be agile, mobile, and flexible in order to accommodate the expanding numbers of MDD organs. By identifying "hard to place" MDD kidneys early and implementing a "fast-track" or open offer policy to expedite placement, the utilization rate of MDDs would improve dramatically. Organ allocation and distribution based on location, motivation, and innovation must lead the way. In the absence of change, we are sacrificing utility for futility and discard rates will continue to escalate.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Rethinking Chronic Kidney Disease in the Aging Population

The process of aging population will inevitably increase age-related comorbidities including chronic kidney disease (CKD). In light of this demographic transition, the lack of an age-adjusted CKD classification may enormously increase the number of new diagnoses of CKD in old subjects with an indolent decline in kidney function. Overdiagnosis of CKD will inevitably lead to important clinical consequences and pronounced negative effects on the health-related quality of life of these patients. Based on these data, an appropriate workup for the diagnosis of CKD is critical in reducing the burden of CKD worldwide. Optimal management of CKD should be based on prevention and reduction of risk factors associated with kidney injury. Once the diagnosis of CKD has been made, an appropriate staging of kidney disease and timely prescriptions of promising nephroprotective drugs (e.g., RAAS, SGLT-2 inhibitors, finerenone) appear crucial to slow down the progression toward end-stage kidney disease (ESKD). The management of elderly, comorbid and frail patients also opens new questions on the appropriate renal replacement therapy for this subset of the population. The non-dialytic management of CKD in old subjects with short life expectancy features as a valid option in patient-centered care programs. Considering the multiple implications of CKD for global public health, this review examines the prevalence, diagnosis and principles of treatment of kidney disease in the aging population.

Current Perspectives in ABO-Incompatible Kidney Transplant

For a long time, ABO incompatible living donor kidney transplantation has been considered contraindicated, due to the presence of isohemagglutinins, natural antibodies reacting with non-self ABO antigens. However, as the demand for kidney transplantation is constantly growing, methods to expand the donor pool have become increasingly important. Thus, in the last decades, specific desensitization strategies for ABOi transplantation have been developed. Nowadays, these regimens consist of transient removal of preformed anti-A or anti-B antibodies by using plasmapheresis or immunoadsorption and B-cell immunity modulation by CD20+ cells depletion with rituximab, in association with maintenance immunosuppression including corticosteroids, tacrolimus and mycophenolate mofetil. The outcome in ABOi kidney transplantation have markedly improved over the years. In fact, although randomized trials are still lacking, recent meta analysis has revealed that there is no difference in terms of graft and patient's survival between ABOi and ABO compatible kidney transplant, even in the long term. However, many concerns still exist, because ABOi kidney transplantation is associated with an increased risk of bleeding and infectious complications, partly related to the effects of extracorporeal treatments and the strong immunosuppression. Thus, a continuous improvement in desensitization strategies, with the aim of minimize the immunosuppressive burden, on the basis of immune pathogenesis, antibodies titers and/or ABO blood group, is warranted. In this review, we discuss the main immune mechanisms involved in ABOi kidney transplantation, the pathogenesis of tolerance and the desensitization regimens, including immunoadsorption and plasmapheresis and the immunosuppressive protocol. Finally, we provide an overview on outcome and future perspectives in ABOi kidney transplant.

The Kidney Donor Profile Index (KDPI) Correlates With Histopathologic Findings in Post-reperfusion Baseline Biopsies and Predicts Kidney Transplant Outcome

Background

The increasing organ shortage in kidney transplantation leads to the necessity to use kidneys previously considered unsuitable for transplantation. Numerous studies illustrate the need for a better decision guidance rather than only the classification into kidneys from standard or expanded criteria donors referred to as SCD/ECD-classification. The kidney donor profile index (KDPI) exhibits a score utilizing a much higher number of donor characteristics. Moreover, graft biopsies provide an opportunity to assess organ quality.

Methods

In a single center analysis 383 kidney transplantations (277 after deceased and 106 after living donation) performed between January 1st, 2006, and December 31st, 2016, retrospectively underwent SCD/ECD and KDPI scoring. Thereby, the quality of deceased donor kidneys was assessed by using the KDPI and the living donor kidneys by using the living KDPI, in the further analysis merged as (L)KDPI. Baseline biopsies taken 10 min after the onset of reperfusion were reviewed for chronic and acute lesions. Survival analyses were performed using Kaplan-Meier analysis and Cox proportional hazards analysis within a 5-year follow-up.

Results

The (L)KDPI correlated with glomerulosclerosis (r = 0.30, p < 0.001), arteriosclerosis (r = 0.33, p < 0.001), interstitial fibrosis, and tubular atrophy (r = 0.28, p < 0.001) as well as the extent of acute tubular injury (r = 0.20, p < 0.001). The C-statistic of the (L)KDPI concerning 5-year death censored graft survival was 0.692. Around 48% of ECD-kidneys were classified as (L)KDPI<85%. In a multivariate Cox proportional hazard analysis including (preformed) panel reactive antibodies, cold ischemia time, (L)KDPI, and SCD/ECD-classification, the (L)KDPI was significantly associated with risk of graft loss (hazard ratio per 10% increase in (L)KDPI: 1.185, 95% confidence interval: 1.033–1.360, p = 0.025). Survival analysis revealed decreased death censored (p < 0.001) and non-death censored (p < 0.001) graft survival in kidneys with an increasing (L)KDPI divided into groups of <35, 35–85, and >85%, respectively.

Conclusion

With a higher granularity compared to the SCD/ECD-classification the (L)KDPI is a promising tool to judge graft quality. The correlation with chronic and acute histological lesions in post-reperfusion kidney biopsies underlines the descriptive value of the (L)KDPI. However, its prognostic value is limited and underlines the urgent need for a more precise prognostic tool adopted to European kidney transplant conditions.

Early Referral, Living Donation, and Preemptive Kidney Transplant

BACKGROUND

Preemptive kidney transplant (PKT) is recognized as the most beneficial and cost-effective form of renal replacement therapy among patients with end-stage renal disease. Despite optimal outcomes and improved quality of life associated with PKT, its use as a first renal replacement therapy remains low among patients with end-stage renal disease. The goal of this retrospective cohort study was to compare, among adult kidney transplant recipients, characteristics across PKT status.

METHODS

We compared the characteristics of patients who did and did not have a PKT over 5 years, from 2010 to 2014, using the electronic health records of Kaiser Permanente Mid-Atlantic States.

RESULTS

A total of 233 patients received a kidney-alone transplant, and, of these, 44 patients (19%) were PKT and 189 patients (81%) were non-PKT. Of the patients in the PKT group, 43% received a kidney from a deceased donor. PKT recipients were more often White, had polycystic kidney disease or glomerulonephritis, received a living donor organ, and were transplanted at certain transplant centers. Estimated glomerular filtration rate on listing for those who received a deceased donor transplant was higher in PKT than non-PKT patients listed pre-dialysis.

CONCLUSIONS

PKT was associated with having a living kidney donor and with having a higher estimated glomerular filtration rate at listing for deceased donor recipients.

Extracellular Vesicles Derived from Mesenchymal Stromal Cells Delivered during Hypothermic Oxygenated Machine Perfusion Repair Ischemic/Reperfusion Damage of Kidneys from Extended Criteria Donors

Simple Summary

In this study, we explore for the first time an innovative tool for organ preservation aimed to preventing ischemia reperfusion injury (IRI) in marginal kidneys from expanded criteria donors (ECD) unsuitable for transplantation. Ex vivo hypothermic oxygenated perfusion (HOPE) with and without MSC-derived EV and normothermic reperfusion (NR) with artificial blood composed of bovine hemoglobin were applied on kidneys to evaluate global renal ischemic damage score, renal ultrastructure, mitochondrial distress, apoptosis, cell proliferation index, and the mediators of energy metabolism. Our study demonstrates that kidney conditioning with HOPE+EV arrests the ischemic damage, prevents reoxygenation-dependent injury, and preserves tissue integrity. EV delivery during HOPE can be considered a new organ preservation strategy to increase the donor pool and improving transplant outcome. The originality of our study lies an EV and HOPE combined novel setting use in kidneys from ECD, but also in any condition for graft dysfunction such as ischemia/reperfusion.

Abstract

The poor availability of kidney for transplantation has led to a search for new strategies to increase the donor pool. The main option is the use of organs from extended criteria donors. We evaluated the effects of hypothermic oxygenated perfusion (HOPE) with and without extracellular vesicles (EV) derived from mesenchymal stromal cells on ischemic/reperfusion injury of marginal kidneys unsuitable for transplantation. For normothermic reperfusion (NR), we used artificial blood as a substitute for red blood cells. We evaluated the global renal ischemic dam-age score (GRS), analyzed the renal ultrastructure (RU), cytochrome c oxidase (COX) IV-1 (a mitochondrial distress marker), and caspase-3 renal expression, the tubular cell proliferation index, hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) tissue levels, and effluent lactate and glucose levels. HOPE+EV kidneys had lower GRS and better RU, higher COX IV-1 expression and HGF and VEGF levels and lower caspase-3 expression than HOPE kidneys. During NR, HOPE+EV renal effluent had lower lactate release and higher glucose levels than HOPE renal effluent, suggesting that the gluconeogenesis system in HOPE+EV group was pre-served. In conclusion, EV delivery during HOPE can be considered a new organ preservation strategy for increasing the donor pool and improving transplant outcome.

Outcome of kidney transplantations from ≥65-year-old deceased donors with acute kidney injury

Kidney transplantation (KT) from donors with acute kidney injury (AKI) has been associated with delayed graft function (DGF) but similar graft survival compared with KT from donors without AKI. Kidneys from ≥65-year-old donors with comorbidities are more susceptible to cold ischemia time and DGF and it is unknown whether such elderly kidneys with AKI can also be transplanted with satisfactory outcomes. All KTs from ≥65-year-old donors performed at our centre from 1999 to 2019 (n = 233) were retrospectively analysed and short- as well as long-term outcomes were compared for KTs from donors with (n = 64) and without AKI (n = 169). There were no significant differences regarding the frequency of DGF as well as the estimated glomerular filtration rate (eGFR) one and three years post-transplant between the no-AKI and the AKI group (DGF: no-AKI 30.2% vs. AKI 40.6%, P = 0.17; eGFR at one-year: 31.9 ml/min/1.73m² vs. 35.5 ml/min/1.73m² , P = 0.32; at three-years: 33.8 ml/min/1.73m² vs. 40.9 ml/min/1.73m² , P = 0.18; respectively). Death-censored graft survival and patient survival were also not significantly different. Multivariable Cox regression analysis did not identify AKI as a significant risk factor for graft loss or death. Following careful donor and recipient selection, kidneys from ≥65-year-old AKI donors may potentially be transplanted with satisfactory outcomes. This article is protected by copyright. All rights reserved.

Desenlaces a largo plazo en pacientes trasplantados renales con donantes de criterios expandidos: experiencia de 10 años

Introducción. El trasplante renal es el tratamiento de elección para la enfermedad renal crónica. Debido a la brecha con la disponibilidad de donantes, el uso de criterios expandidos es una opción que busca mejorar la tasa de donación mundial. El objetivo de este estudio fue comparar la sobrevida del injerto y del paciente trasplantado con donante de criterios expandidos versus el donante estándar. Métodos. Cohorte retrospectiva de 1002 pacientes con trasplante renal donde se determinó la sobrevida del injerto renal y del receptor a 10 años después del trasplante. La sobrevida del injerto renal y el receptor fueron estimadas por el método de Kaplan-Meier. Una regresión de Cox fue realizada ajustando el modelo multivariado. Resultados. El análisis incluyó 1002 receptores, con un 18,8 % (n=189) que correspondían al uso de donante de criterios expandidos. El grupo de trasplante renal con donante de criterios expandidos tuvo menor sobrevida del paciente (48,1 % versus 63,8 %) y del injerto (63,3 % versus 74,7 %) en comparación con el grupo de trasplante renal con donantes con criterios estándar a los 10 años después del trasplante. La asociación de trasplante renal con donante de criterios expandidos y muerte o pérdida del injerto renal no fueron significativas cuando se ajustaron las variables en el modelo multivariado. Conclusión. El trasplante renal con donante de criterios expandidos tiene menor sobrevida del receptor y del injerto frente al grupo de trasplante renal con donante estándar. No hubo diferencias estadísticamente significativas en cuanto al trasplante renal con donante de criterios expandidos frente a la pérdida del injerto renal o muerte.

Peritoneal Dialysis for Potential Kidney Transplant Recipients: Pride or Prejudice?

Kidney transplantation (KT) is recognized as the gold-standard of treatment for patients with end-stage renal disease. Additionally, it has been demonstrated that receiving a pre-emptive KT ensures the best recipient and graft survivals. However, due to an overwhelming discrepancy between the organs available and the patients on the transplant waiting list, the vast majority of transplant candidates require prolonged periods of dialysis before being transplanted. For many years, peritoneal dialysis (PD) and hemodialysis (HD) have been considered competitive renal replacement therapies (RRT). This dualistic vision has recently been questioned by evidence suggesting that an individualized and flexible approach may be more appropriate. In fact, tailored and cleverly planned changes between different RRT modalities, according to the patient’s needs and characteristics, are often needed in order to achieve the best results. While home HD is still under scrutiny in this particular setting, current data seems to favor the use of PD over in-center HD in patients awaiting a KT. In this specific population, the demonstrated advantages of PD are superior quality of life, longer preservation of residual renal function, lower incidence of delayed graft function, better recipient survival, and reduced cost.

Kidney transplant candidates' and recipients' perspectives on the decision-making process to accept or refuse a deceased donor kidney offer: Trust and graft survival matter

BACKGROUND

The decision to accept a kidney from a deceased donor can be a difficult one. This study aims to capture the perspectives of transplant candidates (TCs) and kidney transplant recipients (KTRs) on the decision-making process when a deceased kidney is offered.

METHODS

We conducted six focus groups with KTRs and TCs. The content of the focus groups was analyzed using the qualitative thematic method.

RESULTS

KTRs reported that the experience of being offered a kidney could be difficult because of the circumstances of the offer and unpreparedness to participate in the discussion. Both KTRs and TCs trusted the medical expertise. Age and having experience with dialysis could influence the decision to accept an offer. In order to engage in the discussion, patients wanted to obtain estimates of expected graft survival. Patients did not express interest for a web-based calculator for patient use, but expected transplant physicians to summarize and explain the information that would impact graft survival time.

CONCLUSION

TCs and KTRs wanted to be involved in the decision to accept a deceased donor kidney. Tools that can help physicians communicate the risks and benefits of accepting an offer could improve patient participation in the decision-making process.

Hepatitis C positive organ transplantation to negative recipients at a multiorgan Canadian transplant centre: ready for prime time

BACKGROUND

Transplantation offers the best survival for patients with end stage organ disease. Transplant of hepatitis C virus (HCV) nucleic acid test (NAT) positive organs into negative recipients is a novel strategy that can expand the donor pool. We aim to evaluate our centre's experience.

METHODS

We preformed a retrospective review of anti-HCV NAT positive and negative organs into negative recipients transplanted over 27 months. Primary outcome was the success rate of eradication of HCV post-transplant. Secondary outcomes were rate of transmission of HCV, treatment adverse events, and graft failure.

RESULTS

33 anti-HCV positive organs were transplanted into negative recipients. 22 (66.7%) were NAT positive. Median recipients age was 49 years (interquartile range [IQR] 44.5-62.0) with the majority being males (57.6%). NAT positive organ transplantations included 16 kidneys, 3 livers, 1 kidney-pancreas, 1 liver-kidney, and 1 heart. The most common HCV genotype was 1a (59.1%). The median time to initiating therapy was 41.5 days. SVR12 was 100% in patients who finished therapy. There were no adverse events with therapy and no graft failure.

CONCLUSIONS

Anti-HCV NAT positive organ transplantation into negative recipients is safe with excellent eradication rates and no significant adverse events or graft failure. This would expand donor pool to close the gap between supply and demand.

A Statistical Prediction Model for Survival After Kidney Transplantation from Deceased Donors

Background

In an environment of limited kidney donation resources, patient recovery and survival after kidney transplantation (KT) are highly important. We used pre-operative data of kidney recipients to build a statistical model for predicting survivability after kidney transplantation.

Material/Methods

A dataset was constructed from a pool of patients who received a first KT in our hospital. For allogeneic transplantation, all donated kidneys were collected from deceased donors. Logistic regression analysis was used to change continuous variables into dichotomous ones through the creation of appropriate cut-off values. A regression model based on the least absolute shrinkage and selection operator (LASSO) algorithm was used for dimensionality reduction, feature selection, and survivability prediction. We used receiver operating characteristic (ROC) analysis, calibration, and decision curve analysis (DCA) to evaluate the performance and clinical impact of the proposed model. Finally, a 10-fold cross-validation scheme was implemented to verify the model robustness.

Results

We identified 22 potential variables from which 30 features were selected as survivability predictors. The model established based on the LASSO regression algorithm had shown discrimination with an area under curve (AUC) value of 0.690 (95% confidence interval: 0.557–0.823) and good calibration result. DCA demonstrated clinical applicability of the prognostic model when the intervention progressed to the possibility threshold of 2%. An average AUC value of 0.691 was obtained on the validation data.

Conclusions

Our results suggest that the proposed model can predict the mortality risk for patients after kidney transplants and could help kidney specialists choose kidney recipients with better prognosis.

Long-standing donor diabetes and pathologic findings are associated with shorter allograft survival in recipients of kidney transplants from diabetic donors

Approximately 6% of deceased kidney donors (DKDs) are diabetic; their kidneys may be associated with worse allograft survival, but published studies suggest that recipient diabetes status has a greater impact on mortality and survival. Since biopsy findings are the most common reason for organ discard, we sought to understand histologic and clinical factors that influence graft survival in patients who receive a kidney from a diabetic DKD. We retrospectively reviewed our institutional experience from 2005 to 2019, and re-evaluated pre-implantation and earliest post-transplant biopsies. Histologic findings were compared against a control cohort of non-diabetic DKD. Of 829 adult DKD transplants, 37 (4.5%) came from diabetic donors. There was no significant difference in diabetic vs. non-diabetic DKD graft survival for all-comers; however, when stratified by duration of donor diabetes, donor diabetes ≥6 years was associated with graft failure. In 25 patients with post-transplant biopsies available, diabetic DKD allografts had significantly greater non-glomerular chronic injury than non-diabetic DKD allografts. Moderate arteriolar hyalinosis (in 24%), moderate tubular atrophy and interstitial fibrosis (IFTA, in 36%), and diabetic glomerulopathy (in 24%) on early post-transplant biopsy were associated with allograft failure. Pre-implantation frozen section discrepancies were more common in long-standing donor diabetes, and arteriolar hyalinosis and IFTA scores on frozen accurately prognosticated graft loss. There was no morphologic improvement in lesions of diabetic nephropathy on short-term follow-up. In conclusion, donor diabetes ≥6 years, and histologic findings on frozen section and early post-transplant biopsy are associated with diabetic DKD allograft loss.

Dual kidney transplants from adult marginal donors: Review and perspective

The practice of dual kidney transplantation (DKT) from adult marginal deceased donors (MDDs) dates back to the mid-1990s with initial pioneering experiences reported by the Stanford and Maryland groups, at which time the primary indication was estimated insufficient nephron mass from older donors. Multiple subsequent studies of short and long-term success have been reported focusing on three major aspects of DKT: Identifying appropriate selection criteria and developing scoring systems based on pre- and post-donation factors; refining technical aspects; and analyzing mid-term outcomes. The number of adult DKTs performed in the United States has declined in the past decade and only about 60 are performed annually. For adult deceased donor kidneys meeting double allocation criteria, >60% are ultimately not transplanted. Deceased donors with limited renal functional capacity represent a large proportion of potential kidneys doomed to either discard or non-recovery. However, DKT may reduce organ discard and optimize the use of kidneys from MDDs. In an attempt to promote utilization of MDD kidneys, the United Network for Organ Sharing introduced new allocation guidelines pursuant to DKT in 2019. The purpose of this review is to chronicle the history of DKT and identify opportunities to improve utilization of MDD kidneys through DKT. This article is protected by copyright. All rights reserved.

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.

Chimerism and tolerance: past, present and future strategies to prolong renal allograft survival

PURPOSE OF REVIEW

Immunological factors are a major cause of kidney allograft loss. Calcineurin inhibitors (CNIs) have improved short-term kidney allograft survival; however, they in turn contribute to long-term kidney allograft loss from chronic CNI nephrotoxicity. Tolerance induction in transplantation can avoid the long-term adverse effects of immunosuppressive medications. This review aims to critically discuss recent efforts in inducing transplantation tolerance.

RECENT FINDINGS

Tolerance induction mediated by chimerism has shown some promise in minimizing or even complete withdrawal of immunosuppressive treatments in kidney allograft recipients. There has been a number of approaches as varied as the number of centres conducting these trials. However, they can be grouped into those mediated by transient microchimerism and those facilitated by more stable macro or full donor chimerism. The success rates in terms of long-term drug-free graft survival has been limited in microchimerism-mediated tolerance induction approaches. Mixed macrochimerism of less than 50% donor may be unstable with mostly the recipient's native immune system overpowering the donor chimeric status.Tolerance induction leading to chimerism has been limited to living donor kidney transplantation and additional long-term outcomes are required. Furthermore, immune monitoring after tolerance induction has faced a limitation in studying due to a lack of sufficient study participants and appropriate study controls.

SUMMARY

Tolerance induction is one of several strategies used to prolong kidney allograft survival, but it has not been routinely utilized in clinical practice. However, future applications from the trials to clinical practice remain limited to living donor kidney transplantation. Once further data regarding tolerance inductions exist and practicality becomes widely accepted, tolerance induction may shift the paradigm in the field of kidney transplantation to achieve the best possible outcome of 'One Organ for Life'.

Early Graft Loss Following Transplantation From Expanded Criteria Donors

Background

Expanded criteria donor (ECD) kidneys are associated with higher graft loss rates than standard criteria donor kidneys. We sought to determine factors associated with early graft loss and their discrimination ability for this outcome compared with kidney donor risk index.

Methods

Data were extracted from the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) for ECD transplants between 1997 and 2014. The primary outcome was early graft loss (all-cause graft loss within 3 y of transplantation). Death-censored graft loss was substituted as a sensitivity analysis. Era-adjusted odds ratios were calculated by multivariable logistic regression for donor, recipient, and transplant factors available at transplantation. Discrimination was assessed by c-statistic, with 95% confidence intervals (CIs) calculated by bootstrapping.

Results

Of 2152 ECD kidney transplants, early graft loss occurred in 406 (19%) and was associated with recipient diabetes, smoking, First Nations recipients, and oliguria. Of factors defining ECD (age, elevated terminal creatinine, hypertension, death from cerebrovascular accident), all but mode of death were associated with early graft loss. The multivariable model, including known donor, recipient, and transplant factors, was moderately good at predicting early graft loss (c-statistic 0.65; 95% CI, 0.62-0.68). Recipient factors (c-statistic 0.62; 95% CI, 0.59-0.65) performed equally well compared with donor factors (c-statistic 0.60; 95% CI, 0.57-0.64) or the kidney donor risk index (c-statistic 0.60; 95% CI, 0.56-0.63).

Conclusions

Early graft loss occurs in approximately one-fifth of ECD kidney transplants. The discriminatory value of commonly used recipient, donor, and transplant factors are approximately comparable and limited.

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.

Age disparities in transplantation

PURPOSE OF REVIEW

The aim of this review is to outline disparities in liver and kidney transplantation across age spectrum. Disparities do not involve only recipients whose age may severely affect the possibility to access to a potentially life-saving procedure, but donors as well. The attitude of transplant centers to use older donors reflects on waiting list mortality and drop-out. This review examines which age categories are currently harmed and how different allocation systems may minimize disparities.

RECENT FINDINGS

Specific age categories suffer disparities in the access to transplantation. A better understanding of how properly evaluate graft quality, a continuous re-evaluation of the most favorable donor-to-recipient match and most equitable allocation system are the three key points to promote 'justice and equality' among transplant recipients.

SUMMARY

The duty to protect younger patients waiting for transplantation and the request of older patients to have access to potentially life-saving treatment urge the transplant community to use older organs thus increasing the number of available grafts, to evaluate new allocation systems with the aim to maximize 'utility' while respecting 'equity' and to avoid 'futility' thus minimizing waiting list mortality and drop-out, and improving the survival benefits for all patients requiring a transplant.

VIDEO ABSTRACT

http://links.lww.com/COOT/A9.

Polymorphisms in the CYP3A5 gene significantly affect the pharmacokinetics of sirolimus after kidney transplantation

Aim: Sirolimus (SIR) is an immunosuppressant with limitations, including a narrow treatment window, multiple adverse reactions and large differences within and among individuals. Objective: The correlation between numerous SNPs and SIR in terms of trough concentration in the early stage after kidney transplantation was analyzed. Materials & methods: A retrospective cohort study involving 69 kidney transplantation recipients was designed. Blood samples were collected to extract total DNAs, and trough SIR concentrations were measured. Logistic regression was used to analyze the association between SNPs and SIR trough concentrations. Results: At 7 days, 1 month and 3 months, the mean SIR trough concentration of patients in the CYP3A5 rs4646453-CC group was significantly higher than that in the CYP3A5 rs4646453-AA and CYP3A5 rs4646453-CA groups (p < 0.001) and CYP3A5 rs15524-AA group was significantly higher than that in the CYP3A5 rs15524-AG and CYP3A5 rs15524-GG groups (p < 0.001). Conclusion: Our study indicated that both CYP3A5 rs4646453 and CYP3A5 rs15524 had a certain influence on SIR trough concentration at 7 days, 1 month and 3 months.

Comparison of estimated glomerular filtration rate of marginal versus standard renal allograft: A prospective cohort study

Introduction:

The end-stage renal disease (ESRD) population is increasing worldwide and organ shortage is an important issue. The disparity between the availability of organs and waitlisted patients for transplants has forced many transplant centers across the world to use marginal kidney donors. We assess and compare postoperative estimated glomerular filtration rate (eGFR) in patients who received a graft from marginal renal donor (MRD) versus those who received a graft from standard renal donor (SRD).

Methods:

A total of 214 patients with ESRD underwent open live donor renal allografting from September 2015 to September 2017. Out of 214 donors, 165 (77.1%) were SRD and 49 (22.9%) were MRD. Post-transplant eGFR was calculated at 2 months for donors and at days 1, 3, 5, and 7 and month 1, 3, 6, and 12 for recipients.

Results:

There was no statistically significant difference in eGFR of recipients at preoperative and postoperative period between SRD and MRD groups. Although at 12 months of follow–up eGFR was relatively high in SRD group, it did not show any statistically significant difference. The recipient survival rate at 1-year follow-up was 98.2% in SRD and 100% in MRD group.

Conclusions:

Renal transplant recipients using MRDs have a comparable glomerular filtration rate to SRDs at the end of 1 year. Short-term outcomes in recipients receiving marginal renal grafts were similar when compared to the allograft from standard donors.

A Comparison of Pulsatile Hypothermic and Normothermic Ex Vivo Machine Perfusion in a Porcine Kidney Model

BACKGROUND

Hypothermic machine perfusion (HMP) is a well-established method for deceased donor kidney preservation. Normothermic machine perfusion (NMP) might offer similar or greater advantages. We compared the 2 methods in an ex vivo perfusion model using 34 porcine kidneys.

METHODS

Thirty kidneys were stored on ice for 24 h before undergoing 4 h of HMP (n = 15) or NMP (n = 15) followed by 2 h of normothermic ex vivo reperfusion with whole blood. Four kidneys underwent 28 h of cold static storage followed by 2 h of normothermic ex vivo reperfusion. During the 2 h of normothermic ex vivo reperfusion, perfusate flow rates, urinary output, and oxygen consumption rates were compared between all groups.

RESULTS

Porcine kidneys after HMP showed significantly higher urinary output (5.31 ± 2.06 versus 2.44 ± 1.19 mL/min; P = 0.002), oxygen consumption (22.71 ± 6.27 versus 11.83 ± 1.29 mL/min; P = 0.0016), and perfusate flow rates (46.24 ± 12.49 versus 26.16 ± 4.57 mL/min; P = 0.0051) than kidneys after NMP. TUNEL staining of tissue sections showed significantly higher rates of apoptosis in kidneys after NMP (P = 0.027).

CONCLUSIONS

In our study, the direct comparison of HMP and NMP kidney perfusion in a translational model demonstrated superiority of HMP; however, further in vivo studies would be needed to validate those results.