Long-term effects of delayed graft function duration on function and survival of deceased donor kidney transplants

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.

Biomarker-Development Proteomics in Kidney Transplantation: An Updated Review

Kidney transplantation (KT) is the optimal therapeutic strategy for patients with end-stage renal disease. The key to post-transplantation management is careful surveillance of allograft function. Kidney injury may occur from several different causes that require different patient management approaches. However, routine clinical monitoring has several limitations and detects alterations only at a later stage of graft damage. Accurate new noninvasive biomarker molecules are clearly needed for continuous monitoring after KT in the hope that early diagnosis of allograft dysfunction will lead to an improvement in the clinical outcome. The advent of “omics sciences”, and in particular of proteomic technologies, has revolutionized medical research. Proteomic technologies allow us to achieve the identification, quantification, and functional characterization of proteins/peptides in biological samples such as urine or blood through supervised or targeted analysis. Many studies have investigated proteomic techniques as potential molecular markers discriminating among or predicting allograft outcomes. Proteomic studies in KT have explored the whole transplant process: donor, organ procurement, preservation, and posttransplant surgery. The current article reviews the most recent findings on proteomic studies in the setting of renal transplantation in order to better understand the effective potential of this new diagnostic approach.

Renal transplant anastomotic time-Every minute counts!

The impact of anastomotic time in renal transplant is under recognized and not well studied. It is one of the few controllable factors that affect the incidence of delayed graft function (DGF). Our study aimed at quantifying the impact of anastomotic time. We performed a retrospective review of 424 renal transplants between the years 2006 and 2020. A total of 247 deceased donor renal transplants formed the study cohort. Patients were divided into two groups based on the presence or absence of DGF. Variables with p < 0.3 were analyzed using the binary logistic regression test. The final analysis showed anastomotic time to be significantly associated with DGF with odds ratio of 1.04 per minute corresponding to 4% increase in DGF incidence with every minute increment in anastomotic time. Other variables that had significant impact on DGF were DCD donor (odds ratio - 8.7) and donor terminal creatinine. We concluded that anastomotic time had significant impact on the development of DGF and hence should be minimized.

Effects of Delayed Graft Function on Transplant Outcomes: A Meta-analysis

Delayed graft function (DGF) is a frequent complication of kidney transplantation, but its impact on long- and short-term transplant outcomes is unclear. We conducted a systematic literature search for studies published from 2007 to 2020 investigating the association between DGF and posttransplant outcomes. Forest plots stratified between center studies and registry studies were created with pooled odds ratios. Posttransplant outcomes including graft failure, acute rejection, patient mortality, and kidney function were analyzed. Of the 3422 articles reviewed, 38 papers were included in this meta-analysis. In single-center studies, patients who experienced DGF had increased graft failure (odds ratio [OR] 3.38; 95% confidence interval [CI], 1.85-6.17; P < 0.01), acute allograft rejection (OR 1.84; 95% CI, 1.30-2.61; P < 0.01), and mortality (OR 2.32; 95% CI, 1.53-3.50; P < 0.01) at 1-y posttransplant. Registry studies showed increased graft failure (OR 3.66; 95% CI, 3.04-4.40; P < 0.01) and acute rejection (OR 3.24; 95% CI, 1.88-5.59; P < 0.01) but not mortality (OR 2.27; 95% CI, 0.97-5.34; P = 0.06) at 1-y posttransplant. DGF was associated with increased odds of graft failure, acute rejection, and mortality. These results in this meta-analysis could help inform the selection process, treatment, and monitoring of transplanted kidneys at high risk of DGF.

Clinical indicators of slow graft function and outcome after pediatric kidney transplantation

BACKGROUND

Lesser degrees of perioperative ischemia-reperfusion injury that does not require dialysis may nonetheless influence allograft outcomes, necessitating evaluation of suitable surrogate indicators of perioperative allograft injury.

METHODS

This retrospective analysis of pediatric kidney transplants evaluated two indicators representing pace and completeness of recovery, for association with 12-month estimated glomerular filtration rate (eGFR) and first-year rate of eGFR decline: time to creatinine nadir (TTN) and ratio of recipient/donor unadjusted GFR (uGFR_R/D ) at 1-month post-transplant. Donor, recipient, and perioperative risk factors were tested further for association with these 2 indicators.

RESULTS

179 patients (190 transplants) aged 13 (IQR 7-17) years and 56% male were included. Twelve-month eGFR was strongly associated with unadjusted GFR at 1 month (uGFR_1M , p < .001) and uGFR_R/D (p = .003), but not with TTN. None of the indicators was associated with the rate of subsequent eGFR decline after 1-month post-transplant. As a potential surrogate indicator, uGFR_1M is effectively modeled by TTN and uGFR_R/D (adjusted R²  = 0.57) and is associated with 12-month eGFR (β = 0.81 ± 0.08; p < .001). Clinical factors associated with uGFR_R/D included donor uGFR (p < .001), BSA (p = .026), age (p = .074), and recipient BSA (p < .001). Factors associated with pace of recovery (TTN) included donor uGFR (p = .018), type (p = .019), and recipient BSA (p = .022).

CONCLUSIONS

The uGFR_R/D ratio, but not TTN, is a useful indicator of perioperative allograft damage that is associated with one-year functional outcome; and uGFR_1M is a potential early surrogate outcome. Donor, recipient, and perioperative factors that are associated with slow allograft function are identified.

Presence of CD163+ macrophages in DCD kidneys with high DGF reduces the risk for acute cellular rejection in 6 months after kidney transplantation

Acute cellular rejection (ACR) occurs in 10% of renal allograft recipients and is characterized by leukocyte infiltration as observed in needle biopsies. ACR onset is subject to several risk factors, including delayed graft function (DGF). As the impact of DGF on the etiology of ACR remains unclear, this study analyzed the association between presence of leukocyte subsets and ACR onset, in DCD kidney biopsies with extensive DGF following transplantation. Immunohistochemical analysis of protocol biopsies taken 10 days after kidney transplantation revealed that patients with high levels of renal CD163⁺ macrophages have a decreased risk (OR = 0.021, P = 0.008) for ACR in the first 6 months after transplantation. In pre-transplant biopsies of a comparable DCD cohort, with >80% DGF, presence of donor CD163+ macrophages showed no effect on ACR risk. Therefore, leukocyte infiltrate present during the inflammatory response at the time of DGF may contain anti-inflammatory macrophages that exert a protective effect against ACR development.

Delayed Graft Function Duration in Deceased Donor Kidney Transplants

BACKGROUND

Delayed graft function (DGF) is an important prognostic indicator after kidney transplantation. Depending on the severity of the ischemia-reperfusion injury, DGF can have several clinical presentations, with different renal function recovery times. Both the presence and duration of DGF can have an impact on kidney transplantation outcomes. However, the definition of the cutoff point, above which the outcomes are worse, varies widely in the literature.

METHODS

To investigate the impact of DGF and its duration on patient and graft survivals, a single-center retrospective study including all deceased donor kidney transplants was performed between November 2008 and December 2015 (n = 188). Through the analysis on the receiver operating characteristic curve, the cutoff point that determined the worst outcome was reached. DGF patients were then divided according to the duration of DGF (<8 days or ≥8 days).

RESULTS

The overall incidence of DGF was 62.2%. Higher HLA mismatches was an independent risk factor for prolonged DGF. DGF ≥8 days was associated with acute rejection and this one was associated with patient death in 3 years.

CONCLUSION

DGF with a duration of more than 8 days associated with higher HLA mismatches increases the risk of acute rejection, but graft loss and patient survival are not affected by DGF, regardless of its duration.

Delayed Graft Function Under the Microscope: Surveillance Biopsies in Kidney Transplantation

Delayed graft function (DGF) is a common complication of kidney transplantation and frequently leads to the necessity of surveillance biopsies. The purpose of this study is to describe the histological findings in surveillance biopsies of deceased donor kidney transplant recipients and evaluate the risk factors for graft outcomes. This is a monocentric, retrospective study including kidney transplant recipients that underwent a graft biopsy during the DGF period between January 2006 and July 2019. 356 biopsies were performed in 335 deceased donor transplant recipients. Biopsies were analyzed according to the Banff classification. The main histological findings were: acute tubular necrosis in 150 biopsies (42.1%), acute rejection in 96 biopsies (26.9%), and borderline findings in 91 biopsies (25.5%). In the multivariate analysis, recipient age (p = 0.028) and DGF duration (p = 0.005) were associated with rejection, antibody-induction with anti-thymocyte globulin (ATG) was protective (p = 0.001). The occurrence of rejection was associated with lower death-censored graft survival (log-rank; p = 0.009). Surveillance biopsies of kidney grafts experiencing DGF remain an essential tool for the care of kidney transplant recipients. The recipient’s age and duration of DGF are independent risk factors for acute rejection, while antibody-induction therapy with ATG is associated with protection from its occurrence.

The Perspectives of Biomarkers in Predicting the Survival of the Renal Graft

Kidney transplantation (KT) is currently the elective approach for patients with end-stage renal disease. Although it is a safe choice for these patients, the early complications can lead to graft dysfunction. One of the most redoubtable complications is delayed graft function (DGF), having no specific treatment. The effects of DGF on the graft survival are large enough to justify the formulation of specific biological protocols. Therefore, discovering biomarkers of acute impairment in renal transplanted patients is required. Creatinine is a poor marker to establish the kidney injury. Estimated glomerular filtration rate together with creatinine is ready to approximately measure the kidney function. Different serum and urine proteins are being studied as possible predictive biomarkers for delayed graft function. This review will concentrate on recent and existing research which provide insight concerning the contribution of some molecules for the estimation and evaluation of graft function after kidney transplantation. Further studies examining various aspects of DGF after KT are urgently needed to address a hitherto less-known clinical question.

Artificial Intelligence-A Tool for Risk Assessment of Delayed-Graft Function in Kidney Transplant

Delayed-graft function (DGF) might be responsible for shorter graft survival. Therefore, a clinical tool predicting its occurrence is vital for the risk assessment of transplant outcomes. In a single-center study, we conducted data mining and machine learning experiments, resulting in DGF predictive models based on random forest classifiers (RF) and an artificial neural network called multi-layer perceptron (MLP). All designed models had four common input parameters, determining the best accuracy and discriminant ability: donor’s eGFR, recipient’s BMI, donor’s BMI, and recipient–donor weight difference. RF and MLP designs, using these parameters, achieved an accuracy of 84.38% and an area under curve (AUC) 0.84. The model additionally implementing a donor’s age, gender, and Kidney Donor Profile Index (KDPI) accomplished an accuracy of 93.75% and an AUC of 0.91. The other configuration with the estimated post-transplant survival (EPTS) and the kidney donor risk profile (KDRI) achieved an accuracy of 93.75% and an AUC of 0.92. Using machine learning, we were able to assess the risk of DGF in recipients after kidney transplant from a deceased donor. Our solution is scalable and can be improved during subsequent transplants. Based on the new data, the models can achieve better outcomes.

Emerging biomarkers of delayed graft function in kidney transplantation

Delayed Graft Function (DGF) is one of the most common early complications in kidney transplantation, associated with poor graft outcomes, prolonged post-operative hospitalization and higher rejection rates. Given the severe shortage of high-quality organs for transplantation, DGF incidence is expected to raise in the next years because of the use of nonstandard kidneys from Extended Criteria Donors (ECD) and from Donors after Circulatory Death (DCD). Alongside conventional methods for the evaluation of renal allograft [e.g. serum creatinine Glomerular Filtration Rate (GFR), needle biopsy], recent advancements in omics technologies, including proteomics, metabolomics and transcriptomics, may allow to discover novel biomarkers associated with DGF occurrence, in order to identify early preclinical signs of renal dysfunction and to improve the quality of graft management. Here, we gather contributions from basic scientists and clinical researchers to describe new omics studies in renal transplantation, reporting the emerging biomarkers of DGF that may implement and improve conventional approaches.

Effect of Delayed Graft Function on the Outcome and Allograft Survival of Kidney Transplanted Patients from a Deceased Donor

BACKGROUND

In kidney transplantation (KT), delayed graft function (DGF) is a significant early complication observed in the first week. The study aimed to investigate the impact of DGF on the outcome, allograft, and patient survival after KT with organs from deceased donors.

METHODS

This retrospective study was conducted using 304 KT patients who received an organ from deceased donors from 2008 to 2018. The patients were divided into 2 groups, DGF positive (DGF⁺) and DGF negative (DGF^-). The database containing the clinical, laboratory, and immunologic information of donors and recipients was statistically analyzed using the SSPS program.

RESULTS

In this study, 189 (62.17%) were DGF⁺ and 115 (37.83%) were DGF^-. Until 6 months after KT, the estimate glomerular filtration rate was better in group DGF^-, but it was similar between the groups during 10-year follow-up. Graft losses were higher in DGF⁺ group than in the DGF^- (P = .046). The serum creatinine level was persistently higher in DGF⁺ group until the sixth month (P ≤ .05). Allograft survival rates were better in patients who were DGF^- (P = .033). Those who had DGF for more than 15 days had a worse graft survival (P = .003), but in 10 year follow-up, patient survival rates were similar (P = .705).

CONCLUSION

DGF⁺ patients were associated with dialysis time before KT, ischemia time, and the donors' clinical status, such as age, organ quality, and serum creatinine. All these factors had a great impact on graft survival but not on patient survival.

Long Hemodialysis Duration Predicts Delayed Graft Function in Renal Transplant Recipients From Living Donor: A Single-Center Study

BACKGROUND

This study aims to determine the ratio of delayed graft function in renal transplant recipients from living donors and the predictive value of hemodialysis time before transplant for delayed graft function.

METHODS

We conducted a study on 116 adult patients who were diagnosed with end-stage kidney disease and were treated with hemodialysis and transplanted kidneys from living donors for 2 years (from June 2018 to June 2020). Delayed graft function event was collected for each patient.

RESULTS

The recipients had a median age of 36.5 years old, in which 55.2% of them were men, 4.3% of them had the diabetic mellitus, and the median hemodialysis duration was 6 months. The ratio of positive panel-reactive antibody was 33.6% and vascular reconstruction of the donor's kidney was 16.4%. The ratio of delayed graft function was 12.2% (14 of 116 patients). Delayed graft function significantly related to positive panel-reactive antibody, long duration of hemodialysis before transplant, and vascular reconstruction of donor's kidney with P < .001. Duration of hemodialysis before kidney transplant had a predictive value for delayed graft function (area under the curve, 0.83; P < .001).

CONCLUSION

Delayed graft function was not rare in renal transplant recipients from living donors. Duration of hemodialysis before kidney transplant was a good predictor for delayed graft function.

Exploring the causes of the high incidence of delayed graft function after kidney transplantation in Brazil: a multicenter study

This retrospective multicenter (n = 18) cohort study evaluated the incidence, risk factors, and the impact of delayed graft function (DGF) on 1-year kidney transplant (KT) outcomes. Of 3992 deceased donor KT performed in 2014-2015, the incidence of DGF was 54%, ranging from 29.9% to 87.7% among centers. Risk factors (_{lower-bound-95%CI} OR _{upper-bound-95%CI} ) were male gender (_1.066 1.249_1.463 ), diabetic kidney disease (_1.053 1.296_1.595 ), time on dialysis (_1.005 1.007_1.009 ), retransplantation (_1.035 1.397_1.885 ), preformed anti-HLA antibodies (_1.011 1.383_1.892 ), HLA mismatches (_1.006 1.066_1.130 ), donor age (_1.011 1.017_1.023 ), donor final serum creatinine (sCr) (_1.239 1.317_1.399 ), cold ischemia time (CIT) (_1.031 1.043_1.056 ), machine perfusion (_0.401 0.542_0.733 ), and induction therapy with rabbit antithymocyte globulin (rATG) (_0.658 0.800_0.973 ). Duration of DGF > 4 days was associated with inferior renal function and DGF > 14 days with the higher incidences of acute rejection, graft loss, and death. In conclusion, the incidence and duration of DGF were high and associated with inferior graft outcomes. While late referral and poor donor maintenance account for the high overall incidence of DGF, variability in donor and recipient selection, organ preservation method, and type of induction agent may account for the wide variation observed among transplant centers.

A Retrospective Propensity Score Matched Analysis Reveals Superiority of Hypothermic Machine Perfusion over Static Cold Storage in Deceased Donor Kidney Transplantation

Hypothermic machine perfusion (HMP) has been introduced as an alternative to static cold storage (SCS) in kidney transplantation, but its true benefit in the clinical routine remains incompletely understood. The aim of this study was to assess the effect of HMP vs. SCS in kidney transplantation. All kidney transplants performed between 08/2015 and 12/2019 (n = 347) were propensity score (PS) matched for cold ischemia time (CIT), extended criteria donor (ECD), gender mismatch, cytomegalovirus (CMV) mismatch, re-transplantation and Eurotransplant (ET) senior program. A total of 103 HMP and 103 SCS instances fitted the matching criteria. Prior to PS matching, the CIT was longer in the HMP group (17.5 h vs. 13.3 h; p < 0.001), while the delayed graft function (DGF) rates were 29.8% and 32.3% in HMP and SCS, respectively. In the PS matched groups, the DGF rate was 64.1% in SCS vs. 31.1% following HMP: equivalent to a 51.5% reduction of the DGF rate (OR 0.485, 95% CI 0.318–0.740). DGF was associated with decreased 1- and 3-year graft survival (100% and 96.3% vs. 90.8% and 86.7%, p = 0.001 and p = 0.008) or a 4.1-fold increased risk of graft failure (HR = 4.108; 95% CI: 1.336–12.631; p = 0.014). HMP significantly reduces DGF in kidney transplantation. DGF remains a strong predictor of graft survival.