A Review of Donor Acute Kidney Injury and Posttransplant Outcomes

Multivariable Predictors of Poorer Renal Function Among 1119 Deceased Donor Kidney Transplant Recipients During the First Year Post-Transplant, With a Particular Focus on the Influence of Individual KDRI Components and Donor AKI

Given our desire to reduce kidney transplant waiting times by utilizing more difficult-to-place ("higher-risk") DD kidneys, we wanted to better understand post-transplant renal function among 1119 adult DD recipients consecutively transplanted during 2016-2019. Stepwise linear regression of eGFR (CKD-EPI formula) at 3-, 6-, and 12-months post-transplant (considered as biomarkers for longer-term outcomes), respectively, was performed to determine the significant multivariable baseline predictors, using a type I error ≤ 0.01 to avoid spurious/weak associations. Three unfavorable characteristics were selected as highly significant in all three models: Older DonorAge (yr) (p < 0.000001), Longer StaticColdStorage Time (hr) (p < 0.000001), and Higher RecipientBMI (p ≤ 0.00003). Other significantly unfavorable characteristics included: Shorter DonorHeight (cm) (p ≤ 0.00001), Higher Natural Logarithm {Initial DonorCreatinine} (p ≤ 0.001), Longer MachinePerfusion Time (p ≤ 0.003), Greater DR Mismatches (p = 0.01), DonorHypertension (p ≤ 0.004), Recipient HIV+ (p ≤ 0.006), DCD Kidney (p = 0.002), Cerebrovascular DonorDeath (p = 0.01), and DonorDiabetes (p = 0.01). Variables not selected into any model included DonorAKI Stage (p ≥ 0.24), Any DonorAKI (p ≥ 0.04), and five KDRI components: two DonorAge splines at 18 years (p ≥ 0.52) and 50 years (p ≥ 0.28), BlackDonor (p ≥ 0.08), DonorHCV+ (p ≥ 0.06), and DonorWeight spline at 80 kg (p ≥ 0.03), indicating that DonorAKI and the weaker KDRI components have little, if any, prognostic impact on renal function during the first 12 months post-transplant. Additionally, biochemical determinations with skewed distributions such as DonorCreatinine are more accurately represented by natural logarithmic transformed values. In conclusion, one practical takeaway is that donor AKI may be ignored when evaluating DD risk.

Outcomes of Kidney Transplantation From Donors on Renal Replacement Therapy

Background

The increasing demand for organs has pushed transplant providers to expand kidney acceptance criteria. The use of kidneys from donors with AKI has been shown to provide good long-term graft survival. We aim to evaluate and compare the outcomes of deceased donor kidney transplantation from donors with acute kidney injury (AKI), either with or without renal replacement therapy (AKI-RRT) before donation.

Methods

A single-center retrospective review of all patients who underwent deceased donor kidney transplantation from AKI donors between 2009 and 2020 was performed. AKI donors were defined on the basis of donor terminal creatinine ≥2.0 mg/dL or use of RRT before donation. We compared the outcomes of recipients receiving a kidney from a donor with AKI versus AKI-RRT. Data are presented as medians (interquartile ranges) and numbers (percentages).

Results

Four hundred ninety-six patients were identified, of whom 300 (60.4%) were men with a median age of 57 y at transplantation. Thirty-nine patients received an AKI-RRT, whereas 457 received an AKI kidney. Donors in the AKI-RRT group were younger (28 versus 40), had less incidence of hypertension (15.3% versus 31.9%), and were more likely to be imported (94.9% versus 76.8%). There was a higher incidence of delayed graft function (72% versus 44%, P < 0.001) in the AKI-RRT group. Recipients in both groups had similar 90-d (100% versus 95.2%) and 1-y (100% versus 91.9%) graft survival. With a median follow-up of 5 y, there was no difference in death-censored graft survival in both groups (P = 0.83).

Conclusions

Careful selection of kidneys from donors with AKI on RRT can be safely used for kidney transplantation with favorable clinical outcomes.

Cysteine as an Innovative Biomarker for Kidney Injury

BACKGROUND

Kidney transplantation is a widely used treatment for end-stage kidney disease. Nevertheless, the incidence of acute kidney injury (AKI) in deceased donors poses a potential hazard because it significantly increases the risk of delayed graft function and potentially exerts an influence on the kidney allograft outcome. It is crucial to develop a diagnostic model capable of assessing the existence and severity of AKI in renal grafts. However, no suitable kidney injury markers have been developed thus far.

METHODS

We evaluated the efficacy of the molecular probe NPO-B, which selectively responds to cysteine, as a new diagnostic tool for kidney injury. We used an in vitro model using ischemia/reperfusion injury human kidney-2 cells and an in vivo ischemia/reperfusion injury mouse model. Additionally, cysteine was investigated using urine samples from deceased donors and living donors to assess the applicability of detection techniques to humans.

RESULTS

This study confirmed that the NPO-B probe effectively identified and visualized the severity of kidney injury by detecting cysteine in both in vitro and in vivo models. We observed that the fluorescence intensity of urine samples measured using NPO-B from the deceased donors who are at a high risk of renal injury was significantly stronger than that of the living donors.

CONCLUSIONS

If implemented in clinical practice, this new diagnostic tool using NPO-B can potentially enhance the success rate of kidney transplantation by accurately determining the extent of AKI in renal grafts.

Acute Kidney Injury in Deceased Organ Donors: Risk Factors And Impacts on Transplantation Outcomes

Background

Acute kidney injury in deceased donors (D-AKI) is one of the common causes of donor kidney discard. The risk factors for D-AKI and its impact on kidney transplantation outcomes are not yet fully understood.

Methods

This single-center, retrospective cohort study included 388 donors referred between June 2021 and December 2022. D-AKI was defined and staged according to kidney disease: Improving global outcomes criteria, and donor clinical variables were analyzed to identify risk factors for D-AKI. Delayed graft function and estimated glomerular filtration rate (eGFR) at 6 mo were evaluated in 369 kidney grafts transplanted from donors with and without D-AKI.

Results

AKI was present in 171 deceased donors (44.1%), with 117 (30.2%) classified as AKI stage 1 and 54 (14%) as AKI stages 2 or 3. Donor history of hypertension (odds ratio [OR] 1.93; 95% confidence interval [CI], 1.21-3.10; P = 0.005), history of diabetes (OR 2.2; 95% CI, 1.21-3.98; P = 0.008), and anoxia as the cause of death (OR 2.61; 95% CI, 1.5-4.61; P < 0.001) were independently associated with an increased risk of D-AKI. Multivariable mixed models identified donor age (β -0.49; 95% CI, -0.71 to -0.28; P < 0.001) as the only independent risk factor for lower eGFR at 6 mo. D-AKI was not associated with delayed graft function or lower eGFR at 6 mo.

Conclusions

Hypertension, diabetes, and anoxia as the cause of death were identified as risk factors for AKI in deceased donors. D-AKI should not be used as the sole criterion to assess the risk of poor graft outcomes. A broader range of donor variables should be considered when evaluating graft viability.

Kidney Transplant Outcomes From Deceased Donors Who Received Dialysis

Importance

Recipient outcomes after kidney transplant from deceased donors who received dialysis prior to kidney donation are not well described.

Objective

To compare outcomes of transplant recipients who received kidneys from deceased donors who underwent dialysis prior to kidney donation vs recipients of kidneys from deceased donors who did not undergo dialysis.

Design, Setting, and Participants

A retrospective cohort study was conducted including data from 58 US organ procurement organizations on deceased kidney donors and kidney transplant recipients. From 2010 to 2018, 805 donors who underwent dialysis prior to kidney donation were identified. The donors who underwent dialysis prior to kidney donation were matched 1:1 with donors who did not undergo dialysis using a rank-based distance matrix algorithm; 1944 kidney transplant recipients were evaluated.

Exposure

Kidney transplants from deceased donors who underwent dialysis prior to kidney donation compared with kidney transplants from deceased donors who did not undergo dialysis.

Main Outcomes and Measures

The 4 study outcomes were delayed graft function (defined as receipt of dialysis by the kidney recipient ≤1 week after transplant), all-cause graft failure, death-censored graft failure, and death.

Results

From 2010 to 2018, 1.4% of deceased kidney donors (805 of 58 155) underwent dialysis prior to kidney donation. Of these 805 individuals, 523 (65%) donated at least 1 kidney. A total of 969 kidneys (60%) were transplanted and 641 kidneys (40%) were discarded. Among the donors with kidneys transplanted, 514 (mean age, 33 years [SD, 10.8 years]; 98 had hypertension [19.1%] and 36 had diabetes [7%]) underwent dialysis prior to donation and were matched with 514 (mean age, 33 years [SD, 10.9 years]; 98 had hypertension [19.1%] and 36 had diabetes [7%]) who did not undergo dialysis. Kidney transplants from donors who received dialysis prior to donation (n = 954 kidney recipients) were associated with a higher risk of delayed graft function compared with kidney transplants from donors who did not receive dialysis (n = 990 kidney recipients) (59.2% vs 24.6%, respectively; adjusted odds ratio, 4.17 [95% CI, 3.28-5.29]). The incidence rates did not significantly differ at a median follow-up of 34.1 months for all-cause graft failure (43.1 kidney transplants per 1000 person-years from donors who received dialysis prior to donation vs 46.9 kidney transplants per 1000 person-years from donors who did not receive dialysis; adjusted hazard ratio [HR], 0.90 [95% CI, 0.70-1.15]), for death-censored graft failure (22.5 vs 20.6 per 1000 person-years, respectively; adjusted HR, 1.18 [95% CI, 0.83-1.69]), or for death (24.6 vs 30.8 per 1000 person-years; adjusted HR, 0.76 [95% CI, 0.55-1.04]).

Conclusions and Relevance

Compared with receiving a kidney from a deceased donor who did not undergo dialysis, receiving a kidney from a deceased donor who underwent dialysis prior to kidney donation was associated with a significantly higher incidence of delayed graft function, but no significant difference in graft failure or death at follow-up.

Short-Term, Mid-Term, and Long-Term Outcomes after Deceased Donor Kidney Transplantation in Patients with AKI: A Systematic Review and Meta-Analysis

Key Points

This study reviews the willingness to use kidneys from donors who have experienced AKI during transplantation and provides a thorough analysis of the existing literature. While delayed graft function is more common, primary nonfunction and acute rejection rates appear comparable, as do allograft function and graft survival compared with non-AKI donor kidneys. Considering the shortage of available organs and the high mortality rate of patients on dialysis, the use of donors with AKI as a source for kidney transplantation is a viable alternative.

Background

AKI is a common complication in hospitalized patients and may occur in potential kidney donors. Observational studies have suggested that kidney transplantation in patients with AKI is feasible and safe, but no systematic evaluation has been performed.

Methods

We performed a systematic review and meta-analysis to evaluate the outcomes of kidney transplantation in patients with AKI. We searched MEDLINE, Embase, Cochrane, Google Scholar, and other databases for studies reporting outcomes of donor kidneys with AKI. We included single-center, multicenter, and registry-based studies and analyzed them according to the definition and severity of AKI. End points were primary and delayed graft function (DGF), primary nonfunction (PNF), length of hospital stay, rejection, graft function, and patient and graft survival at 1, 3, 5, and 8–10 years after transplantation. This study was registered in PROSPERO, number CRD42021260088.

Results

We identified 33 single-center, four multicenter, and seven registry studies with more than 100,000 patients published between 2005 and 2022. Recipients from donors with AKI had a higher risk of DGF (relative risk, 1.51; 95% confidence interval [CI], 1.35 to 1.68). Graft function at discharge was worse in the AKI group (MDCrea [95% CI]: 0.96 mg/dl [0.36 to 1.56, I2=96%], MDGFR [95% CI]: −8.88 ml/min per 1.73 m2 [−15.32 to −2.44, I2=93%]), but improved thereafter and was similar in both groups at 3 months after transplantation (MDCrea [95% CI]: −0.05 mg/dl [−0.18 to 0.07, I2=0%], MDGFR [95% CI]: −1.83 ml/min per 1.73 m2 [−5.29 to 1.63, I2=91%]). Primary nonfunction and patient and graft survival were similar at 1, 3, 5, and 8–10 years after transplantation. There were no differences in rejections regardless of AKI definition and severity.

Conclusions

Transplantation of kidneys with AKI is associated with satisfactory short-term and long-term outcomes and should be pursued to increase the donor pool.

Deceased Kidney Donor Biomarkers: Relationship between Delayed Kidney Function and Graft Function Three Years after Transplantation

With an increasing number of marginal donors, additional methods for the evaluation of cadaveric kidney quality are required. This study aimed to evaluate pretransplant deceased donor serum (s) and urine (u) biomarkers, including neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), interleukin-18, and C-X-C motif chemokine 10 (CXCL10) for predicting early and late graft function. In total, 43 deceased kidney donors and 76 corresponding recipients were enrolled. Delayed graft function (DGF) occurred in 27.6% of cases. sIL-18, sKIM-1, uNGAL, and uKIM-1 were predictors of DGF. A model incorporating sIL-18, uKIM-1, and clinical factors was developed to predict DGF (AUROC 0.863). Univariate analysis showed a negative association between uKIM and graft eGFR at 6, 12, 24, and 36 months, but this was not confirmed in the multivariate analysis. In conclusion, we report a superior performance of donor biomarkers for predicting DGF and later graft function over serum creatinine. Higher levels of donor sIL-18 and uKIM in conjunction with expanded-criteria donors and longer cold ischemia times predicted DGF. With no renal tubular damage in zero-time donor biopsies, higher pretransplant urine and serum NGAL levels were associated with better allograft function one year after transplantation, and sNGAL with graft function three years after transplantation.

Effect of Cardiac Arrest in Brain-dead Donors on Kidney Graft Function

BACKGROUND

Cardiac arrest (CA) causes renal ischemia in one-third of brain-dead kidney donors before procurement. We hypothesized that the graft function depends on the time interval between CA and organ procurement.

METHODS

We conducted a retrospective population-based study on a prospectively curated database. We included 1469 kidney transplantations from donors with a history of resuscitated CA in 2015-2017 in France. CA was the cause of death (primary CA) or an intercurrent event (secondary CA). The main outcome was the percentage of delayed graft function, defined by the use of renal replacement therapy within the first week posttransplantation.

RESULTS

Delayed graft function occurred in 31.7% of kidney transplantations and was associated with donor function, vasopressors, cardiovascular history, donor and recipient age, body mass index, cold ischemia time, and time to procurement after primary cardiac arrest. Short cold ischemia time, perfusion device use, and the absence of cardiovascular comorbidities were protected by multivariate analysis, whereas time <3 d from primary CA to procurement was associated with delayed graft function (odds ratio 1.38).

CONCLUSIONS

This is the first description of time to procurement after a primary CA as a risk factor for delayed graft function. Delaying procurement after CA should be evaluated in interventional studies.

Utilizing kidneys from a donor with bile-cast nephropathy

Here we discuss the successful utilization of a pair of deceased donor kidneys with bile-cast nephropathy. The donor had a kidney donor profile index of 48% and an acute kidney injury requiring continuous renal replacement therapy. Peak donor bilirubin was 40.5 mg/dL, and renal wedge biopsies showed bile-cast nephropathy. Both recipients had delayed graft function lasting up to 4 weeks. The 4-month biopsies showed mild interstitial fibrosis, tubular atrophy, and a resolution of bile casts. These kidney allografts showed the reversible course of cholemic nephropathy and the potential for increasing the utilization of previously discarded kidneys.

Successful transplantation of four kidney grafts from two small pediatric donors with anuric acute renal failure into adult recipients

BACKGROUND

Kidneys from infants with anuric acute kidney injury (AKI) only rarely get accepted for transplantation despite encouraging data that such kidneys can have very good long-term outcome.

METHODS

We report the transplantation of four kidney grafts from two pediatric donors (3 and 4 years) with anuric acute kidney injury as single kidneys into four adult recipients.

RESULTS

All grafts gained function within 14 days posttransplantation, only one recipient needed dialysis after transplantation. None of the recipients suffered from surgical complications. One month after transplantation, all recipients were free of dialysis. Estimated glomerular filtration rates (eGFR) 3 months after transplantation were 37, 40, 50, and 83 mL/min/1.73 m2 . eGFR increased further through month 6, reaching 45, 50, 58, and 89 mL/min/1.73 m2 .

CONCLUSION

These cases highlight the feasibility of successful transplantation of single pediatric kidney grafts into adult recipients despite anuric AKI of the donor.

Short-term outcomes after transplantation of deceased donor kidneys with acute kidney injury: a retrospective analysis of a multicenter cohort of marginal donor kidneys with post-explantation biopsies

BACKGROUND

Deceased donor kidneys with acute kidney injury (AKI) are often discarded because of concerns about inferior transplant outcomes. A means of grading the quality of such kidneys is the performance of procurement biopsies.

METHODS

This is a retrospective study of 221 brain death donors with marginal kidneys transplanted in 223 recipients in Germany. Marginal kidneys were defined as kidneys with procurement biopsies done exceptionally to assess suitability for transplantation in otherwise potentially discarded organs. The impact of deceased donor AKI on patient survival and death-censored graft survival at 1, 3 and 5 years and graft function at 1 and 3 years after transplantation was investigated.

RESULTS

Recipients of kidneys with stage 3 AKI had a greater incidence of delayed graft function [DGF; ORStage 1: 1.435 (95% CI 0.438-0.702), ORStage 2: 2.463 (95% CI 0.656-9.245), ORStage 3: 4.784 (95% CI 1.421-16.101)] but a similar graft and patient survival compared to recipients of donors without AKI and with AKI stage 1 and 2 as well. The coexistence of recipient DGF and donor AKI was associated with the lowest graft survival and function rates.

CONCLUSION

The transplantation of deceased donor marginal kidneys with AKI confers a higher risk for DGF but is associated with acceptable graft and patient outcomes, which do not differ in comparison with marginal donor kidneys without AKI. Graft prognosis is especially poor if donor AKI and recipient DGF concur. Donor AKI was a risk factor independent of the histological lesions of procurement biopsies.

Dynamic changes of neutrophil-to-lymphocyte ratio in brain-dead donors and delayed graft function in kidney transplant recipients

Objectives

Neutrophil-to-lymphocyte ratio (NLR) is a simple parameter implying the inflammatory status. We aimed to explore the association of brain-dead donor NLR change with delayed graft function (DGF) in kidney transplant recipients.

Methods

We retrospectively analyzed the data on 102 adult brain-dead donors and their corresponding 199 kidney transplant recipients (2018 − 2021). We calculated ΔNLR by subtracting the NLR before evaluating brain death from the preoperative NLR. Increasing donor NLR was defined as ΔNLR > 0.

Results

Forty-four (22%) recipients developed DGF after transplantation. Increasing donor NLR was significantly associated with the development of DGF in recipients (OR 2.8, 95% CI 1.2 − 6.6; p = .018), and remained significant (OR 2.6, 95% CI 1.0 − 6.4; p = .040) after adjustment of confounders including BMI, hypertension, diabetes, and the occurrence of cardiac arrest. When acute kidney injury (AKI) was included in the multivariable analysis, increasing donor NLR lost its independent correlation with DGF, while AKI remained an independent risk factor of recipient DGF (OR 4.5, 95% CI 2.7 − 7.6; p < .001). The area under the curve of combined increasing NLR and AKI in donors (0.873) for predicting DGF was superior to increasing donor NLR (0.625, p = .015) and AKI alone (0.859, p < .001).

Conclusions

Dynamic changes of donor NLR are promising in predicting post-transplant DGF. It will assist clinicians in the early recognition and management of renal graft dysfunction. Validation of this new biomarker in a large study is needed.

Deceased Donor Characteristics and Kidney Transplant Outcomes

Kidney transplantation is the therapy of choice for people living with kidney failure who are suitable for surgery. However, the disparity between supply versus demand for organs means many either die or are removed from the waiting-list before receiving a kidney allograft. Reducing unnecessary discard of deceased donor kidneys is important to maximize utilization of a scarce and valuable resource but requires nuanced decision-making. Accepting kidneys from deceased donors with heterogenous characteristics for waitlisted kidney transplant candidates, often in the context of time-pressured decision-making, requires an understanding of the association between donor characteristics and kidney transplant outcomes. Deceased donor clinical factors can impact patient and/or kidney allograft survival but risk-versus-benefit deliberation must be balanced against the morbidity and mortality associated with remaining on the waiting-list. In this article, the association between deceased kidney donor characteristics and post kidney transplant outcomes for the recipient are reviewed. While translating this evidence to individual kidney transplant candidates is a challenge, emerging strategies to improve this process will be discussed. Fundamentally, tools and guidelines to inform decision-making when considering deceased donor kidney offers will be valuable to both professionals and patients.

Acute kidney injury and the compensation of kidney function after nephrectomy in living donation

Acute kidney injury (AKI) incidence is growing rapidly, and AKI is one of the predictors of inpatient mortality. After nephrectomy, all the patients have decreased kidney function with AKI and recover from AKI. However, the characteristic and behavior of AKI is different from usual AKI and compensatory kidney function has been well known in the postoperative setting, especially in living donors. In this review, we have focused on the compensation of kidney function after nephrectomy in living donors. We discuss factors that have been identified as being associated with kidney recovery in donors including age, sex, body mass index, remnant kidney volume, estimated glomerular filtration rate, and various comorbidities.

Trends in the procurement and discard of kidneys from deceased donors with acute kidney injury

Kidney allocation trends from deceased donors with acute kidney injury (AKI) have not been characterized since initial Kidney Donor Profile Index reporting in 2012 and its use under the revised Kidney Allocation System (KAS) in 2014. We conducted a retrospective analysis of US registry data to characterize kidney procurement and discard trends in deceased donors with AKI, defined by ≥50% or ≥0.3 mg/dl (≥4.0 mg/dl or ≥200% for stage 3) increase in terminal serum creatinine from admission. From 2010 to 2020, 172 410 kidneys were procured from 93 341 deceased donors 16 years or older; 34 984 kidneys were discarded (17 559 from AKI donors). The proportion of stage 3 AKI donors doubled from 6% (412/6841) in 2010 to 12% (1365/11493) in 2020. Procurement of stage 3 AKI kidneys increased from 51% (423/824) to 80% (2183/2730). While discard of stage 3 AKI kidneys increased from 41% (175/423) in 2010 to 44% (960/2183) in 2020, this increase was not statistically significant in interrupted time-series analysis following KAS implementation (slope difference -0.41 [-3.22, 2.4], and level change 3.09 [-6.4, 12.6]). In conclusion, the absolute number of stage 3 AKI kidneys transplanted has increased. Ongoing high discard rates of these kidneys suggest opportunities for improved utilization.

Successful outcomes with transplanting kidneys from deceased donors with acute kidney injuryon temporary renal replacement therapy

BACKGROUND AND OBJECTIVES

We aimed to determine outcomes with transplanting kidneys from deceased donors with severe acute kidney injury requiring acute renal replacement therapy (RRT).

MATERIALS AND METHODS

A total of 172 recipients received a kidney from donors with acute kidney injury stage 3 (AKIN3) requiring RRT. We compared the study group to 528 recipients who received a kidney from donors with AKIN stage 3 not on RRT and 463 recipients who received < 85% Kidney Donor Profile Index (KDPI) AKIN stage 0 kidney.

RESULTS

The study group donors were younger compared to the 2 control groups. Despite higher DGF in the study group, the length of hospital stay and acute rejection were similar. Death censored graft survival (96% AKIN3-RRT vs. 97%AKIN3 no RRT vs. 96% KDPI < 85% AKIN0, P = 0.26) and patient survival with functioning graft at 1 year (95% across all groups, P = 0.402) were similar. The estimated glomerular filtration rate were similar across the 3 groups after first month. Interstitial fibrosis and tubular atrophy score ≥ 2 on protocol biopsy at time 0, 4 and 12 months were similar. Primary nonfunction was rare and associated with high KDPI.

CONCLUSIONS

Transplanting selected kidneys from deceased donors with AKIN3 requiring RRT is safe and has good outcomes.

Tubular Cell Dropout in Preimplantation Deceased Donor Biopsies as a Predictor of Delayed Graft Function

Supplemental Digital Content is available in the text.

Background.

Delayed graft function (DGF) affects over 25% of deceased donor kidney transplants (DDKTs) and is associated with increased cost, worsened graft outcomes, and mortality. While approaches to preventing DGF have focused on minimizing cold ischemia, donor factors such as acute tubular injury can influence risk. There are currently no pharmacologic therapies to modify DGF risk or promote repair, in part due to our incomplete understanding of the biology of preimplantation tubular injury.

Methods.

We collected intraoperative, preimplantation kidney biopsies from 11 high-risk deceased donors and 10 living donors and followed transplant recipients for graft function. We performed quantitative high-dimensional histopathologic analysis using imaging mass cytometry to determine the cellular signatures that distinguished deceased and living donor biopsies as well as deceased donor biopsies which either did or did not progress to DGF.

Results.

We noted decreased tubular cells (P < 0.0001) and increased macrophage infiltration (P = 0.0037) in high-risk DDKT compared with living donor biopsies. For those high-risk DDKTs that developed postimplant DGF (n = 6), quantitative imaging mass cytometry analysis showed a trend toward reduced tubular cells (P = 0.02) and increased stromal cells (P = 0.04) versus those that did not (n = 5). Notably, these differences were not identified by conventional histopathologic evaluation.

Conclusions.

The current study identifies donor tubular cell loss as a precursor of DGF pathogenesis and highlights an area for further investigation and potential therapeutic intervention.

Association Between Deceased Donor Acute Kidney Injury Assessed Using Baseline Serum Creatinine Back-Estimation and Graft Survival: Results From the French National CRISTAL Registry

RATIONALE & OBJECTIVE

Deceased donor acute kidney injury (AKI) frequently leads to kidney discards, but its impact on long-term graft survival in kidney transplant recipients remains unclear. We investigated the association between deceased donor AKI assessed using back-estimation of baseline serum creatinine (Scr) and graft survival.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

Adult patients represented within the French CRISTAL registry who received a single kidney allograft from brain-dead deceased donors between January 2006 and December 2017.

EXPOSURE

A back-estimated Scr baseline value was derived for an assumed glomerular filtration rate at 75mL/min/1.73m², using the MDRD Study equation. A refined classification system for donor AKI was implemented as follows: no AKI, undetermined AKI/chronic kidney disease (CKD), recovery from AKI, and ongoing AKI.

OUTCOME

Death-censored graft survival.

ANALYTICAL APPROACH

Multivariable Cox models using a robust variance estimator for paired kidneys from the same donor.

RESULTS

We classified 26,786 recipients as follows: no AKI (n=19,276); undetermined AKI/CKD (n=1,745); recovery from AKI (n=2,392); and ongoing AKI (n=3,373). We observed 4,458 kidney graft losses during a median follow-up period of 5.7 years. Compared with no AKI, ongoing AKI was associated with an increased risk of graft failure (hazard ratio [HR], 1.24 [95% CI, 1.13-1.35]). The HRs for graft failure in the undetermined AKI/CKD and recovery from AKI groups (1.22 [95% CI, 1.07-1.38] and 1.18 [95% CI, 1.06-1.31], respectively) were similar to those observed in the ongoing AKI group. The adverse effect of deceased donor AKI was no longer evident when relying either on the admission or the lowest Scr throughout the procurement procedure as baseline Scr.

LIMITATIONS

No measurement of urine output in donors.

CONCLUSIONS

Deceased donor ongoing AKI, undetermined AKI/CKD, and recovery from AKI according to back-estimated baseline Scr are associated with decreased graft survival. The definition of baseline Scr as the first value measured on admission would have led to a misclassification bias and erroneous estimates.

Impact of acute kidney injury in deceased donors with high Kidney Donor Profile Index on posttransplant clinical outcomes: a multicenter cohort study

BACKGROUND

This study evaluated the impact of acute kidney injury (AKI) on posttransplant clinical outcomes for deceased donor (DD) kidney transplantation (KT) using the Kidney Donor Profile Index (KDPI) system.

METHODS

Overall, 657 kidney transplant recipients (KTRs) receiving kidneys from 526 DDs from four transplant centers were included. We divided them into the high and low KDPI donor groups by 65%, the KDPI score, and both groups were subdivided into the AKI-DDKT and non-AKI-DDKT subgroups according to AKI in DDs.

RESULTS

There was no significant difference in the incidence of delayed graft function (DGF) between the high and low KDPI-KTR groups; however, the AKI-DDKT subgroup showed significantly higher incidence of DGF than the non-AKI-DDKT subgroup in both groups (p = 0.001, p < 0.001, respectively). The death-censored graft survival rate was significantly lower in the high KDPI-KTR group than in the low KDPI-KTR group (p = 0.005). Only in the high KDPI-KTR group, the death-censored graft survival rate was significantly lower in the KT from DDs with AKI stage 3 than KT from DDs with non-AKI or AKI stage 1 or 2 (p = 0.040). The interaction between AKI stage 3 in DDs and high KDPI on the allograft outcome was significant (p = 0.002).

CONCLUSION

KTs from DDs with AKI stage 3 showed an adverse impact on the allograft outcome in the high KDPI-KTR group. Therefore, DDs with a high KDPI score should be managed carefully so that severe AKI does not occur prior to KT.