Risk factors for delayed graft function and their impact on graft outcomes in live donor kidney transplantation

Perioperative Acute Kidney Injury: Diagnosis, Prediction, Prevention, and Treatment

In this review, the authors define acute kidney injury in the perioperative setting, describe the epidemiologic burden, discuss procedure-specific risk factors, detail principles of management, and highlight areas of ongoing controversy and research.

Association between the age-adjusted Charlson Comorbidity Index and complications after kidney transplantation: a retrospective observational cohort study

BACKGROUND

Complications following kidney transplantation elevate the risks of readmission and mortality. The aim of this study was to assess the association between the age-adjusted Charlson Comorbidity Index (ACCI) and postoperative complications among kidney transplant (KT) recipients.

METHODS

Between January 2015 and March 2021, a study involving 886 kidney transplant recipients at the Third Affiliated Hospital of Sun Yat-sen University was conducted. Postoperative complications were defined by the Clavien-Dindo Classification of Surgical Complications. Target Maximum Likelihood Estimation (TMLE) was employed to assess the association between ACCI and postoperative complications. The odds ratio (OR) was computed to determine the relationship between ACCI and postoperative complications. Subsequent interaction and stratified analyses were performed to assess the robustness of the findings.

RESULTS

Out of 859 KT participants ultimately included in the study, 30.7% were documented to have encountered postoperative complications. Participants with an ACCI value exceeding 3 exhibited a notably increased risk of postoperative complications following multivariable adjustment [aOR = 1.64, 95% CI [1.21,2.21], p = 0.001]. Congestive heart failure (OR = 16.18, 95% CI [1.98-132.17], p < 0.001), peripheral vascular disease (OR = 2.32, 95% CI [1.48-3.78], p < 0.001), and chronic obstructive pulmonary disease (OR = 6.05, 95% CI [2.95-12.39], p < 0.001) emerged as the top three preoperative comorbidities significantly linked to postoperative complications in ACCI.

CONCLUSION

An ACCI value exceeding 3 preoperatively constituted a risk factor for postoperative complications among KT patients.

Risk factors of delayed graft function following living donor kidney transplantation: A meta-analysis

INTRODUCTION

Delayed graft function (DGF) is a common condition that necessitates dialysis during the first week after transplantation. Although DGF rarely occurs following living-donor kidney transplantation (LDKT), it may eventually lead to acute or chronic graft rejection. This study aimed to assess the risk factors for DGF in patients who underwent LDKT.

METHODS

A systematic review and meta-analysis of studies published before August 2022 was conducted using the PubMed, Science Direct, Cochrane, and Directory of Open Access Journal (DOAJ) databases. The review included studies that assessed the incidence of DGF following LDKT, and examined its risk factors, while excluding studies involving deceased donors. Potential risk factors were analyzed using pooled mean differences or odds ratios with 95% confidence intervals (CIs). Review Manager 5.3 was used for the meta-analysis.

RESULTS

Among the 13 included studies, 3685 cases of DGF were identified in a total of 113,261 patients (3.25%). Potential risk factors for DGF following LDKT were examined across several aspects, including donor, recipient, donor/recipient relationship, and immunological and intraoperative factors. The identified risk factors included older donors (P = 0.07), male recipients (P < 0.0001), higher recipient body mass index (BMI) (P < 0.0001), non-white recipients (P < 0.0001), pre-existing diabetes (P < 0.0001), pre-existing hypertension (P = 0.01), history of dialysis (P < 0.0001), re-transplantation (P = 0.004), unrelated donor/recipient (P = 0.02), ABO incompatibility (P < 0.0001), higher panel reactive antibody (PRA) levels (P < 0.0001), utilization of right kidney (P < 0.0001), and longer cold ischemia time (CIT) (P = 0.004).

CONCLUSION

Several factors related to the donor, recipient, donor/recipient relationship, and immunological and intraoperative aspects were identified as potential risk factors for the development of DGF following LDKT. Addressing and optimizing these factors may improve the long-term outcomes of LDKT.

Association of Intraoperative Hypotension With Delayed Graft Function Following Kidney Transplant: A Single Centre Retrospective Cohort Study

BACKGROUND

Intraoperative hypotension is associated with acute kidney injury after surgery. However, the definition (duration and magnitude) of hypotension during kidney transplantation (KT) surgery on early graft function remains unclear.

METHODS

We conducted a retrospective cohort study of KT recipients from December 1, 2009, to December 31, 2019. Exposure to intraoperative hypotension was characterized as the duration (minutes) of mean arterial pressure (MAP) <55, <65, <75, and <85 mmHg. Our co-primary outcomes were DGF-creatinine reduction ratio (DGF-CRR, <30% creatinine reduction, postoperative days 1 and 2), and DGF-dialysis (DGF-D, required dialysis within the week of KT for deceased donor recipients). Logistic regression models were fitted to assess this relationship between MAP and DGF.

RESULTS

We included 1602 KT (939 deceased donors, 663 living donors) and 23 were excluded. DGF-CRR occurred in 33% of patients. DGF-CRR was associated with MAP < 65 (>5 min: OR 1.77, 95% confidence interval [CI]: 1.39-2.30; 6-10 min: OR 1.67, 95% CI: 0.97-2.86; 11-20 min: OR 2.18, 95% CI: 1.31-3.63) in unadjusted and <55 mmHg (5 min: OR 1.85, 95% CI: 1.47-2.32; 5-10 min: OR 2.41, 95% CI: 1.65-3.53; 11-20 min: OR 2.36, 95% CI: 1.60, 3.48) in adjusted models. There was also a signal for increased risk of DGF-CRR at MAP < 75 (>5 min: OR 1.69, 95% CI: 1.02-2.80). DGF-D (incidence 35%) in deceased donor KT was not associated with hypotension.

CONCLUSIONS

We found an association between intraoperative hypotension and DGF-CRR at a threshold MAP of 55 mmHg, with a consistent signal toward increased risk at both 65 and 75 mmHg, as indicated by unadjusted models.

An integrated machine learning model enhances delayed graft function prediction in pediatric renal transplantation from deceased donors

BACKGROUND

Kidney transplantation is the optimal renal replacement therapy for children with end-stage renal disease; however, delayed graft function (DGF), a common post-operative complication, may negatively impact the long-term outcomes of both the graft and the pediatric recipient. However, there is limited research on DGF in pediatric kidney transplant recipients. This study aims to develop a predictive model for the risk of DGF occurrence after pediatric kidney transplantation by integrating donor and recipient characteristics and utilizing machine learning algorithms, ultimately providing guidance for clinical decision-making.

METHODS

This single-center retrospective cohort study includes all recipients under 18 years of age who underwent single-donor kidney transplantation at our hospital between 2016 and 2023, along with their corresponding donors. Demographic, clinical, and laboratory examination data were collected from both donors and recipients. Univariate logistic regression models and differential analysis were employed to identify features associated with DGF. Subsequently, a risk score for predicting DGF occurrence (DGF-RS) was constructed based on machine learning combinations. Model performance was evaluated using the receiver operating characteristic curves, decision curve analysis (DCA), and other methods.

RESULTS

The study included a total of 140 pediatric kidney transplant recipients, among whom 37 (26.4%) developed DGF. Univariate analysis revealed that high-density lipoprotein cholesterol (HDLC), donor after circulatory death (DCD), warm ischemia time (WIT), cold ischemia time (CIT), gender match, and donor creatinine were significantly associated with DGF (P < 0.05). Based on these six features, the random forest model (mtry = 5, 75%p) exhibited the best predictive performance among 97 machine learning models, with the area under the curve values reaching 0.983, 1, and 0.905 for the entire cohort, training set, and validation set, respectively. This model significantly outperformed single indicators. The DCA curve confirmed the clinical utility of this model.

CONCLUSIONS

In this study, we developed a machine learning-based predictive model for DGF following pediatric kidney transplantation, termed DGF-RS, which integrates both donor and recipient characteristics. The model demonstrated excellent predictive accuracy and provides essential guidance for clinical decision-making. These findings contribute to our understanding of the pathogenesis of DGF.

The Impact of ABCC2 -24C>T Gene Polymorphism on Graft Survival in Kidney Transplant Recipients

Personalized medicine in kidney transplantation has the potential to improve outcomes and reduce complications. The aim of this study was to investigate the influence of single nucleotide polymorphisms in genes encoding metabolizing enzymes (CYP3A5) and transporters (ABCC2) on clinical outcomes (acute graft failure and/or acute tubular necrosis (ATN)) in kidney transplant recipients (KTR). This was a multicenter, retrospective cohort study where adult KTR who had undergone kidney transplantation between 2020 and 2021 and received tacrolimus-mycophenolate treatment were enrolled in the study. DNA was extracted from collected blood samples using a commercially available kit. CYP3A5*3, ABCC2 -24C>T and ABCC2 3972C>T SNP were determined by polymerase chain reaction. Of the total 39 patients included, nine (23.1%) KTR had an incidence of acute graft failure and/or ATN. A multiple logistic regression showed wildtype ABCC2 -24C>T C allele had a higher risk of developing acute graft rejection and/or ATN compared to the variant allele carriers (adjusted Odd Ratios [aOR]: 27.675, p = 0.038). Recipients who had delayed graft function (aOR: 49.214, p = 0.012) and a history of CMV infection (aOR: 18.097, p = 0.009) were at 49.2 and 18.1-times increased risk for acute graft failure and/or ATN, respectively. The large aOR was inevitable due to the small sample size and required cautious interpretation. This is the first study to determine the effect of the ABCC2 -24C>T genetic polymorphism on clinical outcomes in Malaysian KTR and forms the basis for further work on ABCC2 -24C>T effects in long-term KTR.

Delayed graft function post renal transplantation: a review on animal models and therapeutics

The incidence of end-stage renal disease (ESRD) has been increasing worldwide. Its treatment involves renal replacement therapy, either by dialyses or renal transplantation from a living or deceased donor. Although the initial mortality rates for patients on dialysis are comparable with kidney transplant recipients, the quality of life and long-term prognosis are greatly improved in transplanted patients. However, there is a large gap between availability and need for donor kidneys. This has led to the increase in the use of expanded kidney donor criteria. Allograft dysfunction immediately after transplant sets it up for many complications, such as acute rejection and shorter allograft survival. Delayed graft function (DGF) is one of the immediate posttransplant insults to the kidney allograft, which is increasing in prevalence due to efforts to maximize the available donor pool for kidneys and use of expanded kidney donor criteria. In this review, we discuss the risk factors for DGF, its implications for long-term allograft survival, animal models of DGF, and the therapeutic options currently under evaluation for prevention and management of DGF.

Prediction models for the recipients' ideal perioperative estimated glomerular filtration rates for predicting graft survival after adult living-donor kidney transplantation

Introduction

The impact of the perioperative estimated glomerular filtration rate (eGFR) on graft survival in kidney transplant recipients is yet to be evaluated. In this study, we developed prediction models for the ideal perioperative eGFRs in recipients.

Methods

We evaluated the impact of perioperative predicted ideal and actual eGFRs on graft survival by including 1,174 consecutive adult patients who underwent living-donor kidney transplantation (LDKT) between January 2008 and December 2020. Prediction models for the ideal perioperative eGFR were developed for 676 recipients who were randomly assigned to the training and validation sets (ratio: 7:3). The prediction models for the ideal best eGFR within 3 weeks and those at 1, 2, and 3 weeks after LDKT in 474 recipients were developed using 10-fold validation and stepwise multiple regression model analyzes. The developed prediction models were validated in 202 recipients. Finally, the impact of perioperative predicted ideal eGFRs/actual eGFRs on graft survival was investigated using Fine-Gray regression analysis.

Results

The correlation coefficients of the predicted ideal best eGFR within 3 weeks and the predicted ideal eGFRs at 1, 2, and 3 weeks after LDKT were 0.651, 0.600, 0.598, and 0.617, respectively. Multivariate analyzes for graft loss demonstrated significant differences in the predicted ideal best eGFR/actual best eGFR within 3 weeks and the predicted ideal eGFRs/actual eGFRs at 1, 2, and 3 weeks after LDKT.

Discussion

The predicted ideal best eGFR/actual best eGFR within 3 weeks and the predicted ideal eGFRs/actual eGFRs at 1, 2, and 3 weeks after LDKT were independent prognostic factors for graft loss. Therefore, the perioperative predicted ideal eGFR/actual eGFR may be useful for predicting graft survival after adult LDKT.

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.

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.

Anesthetic Challenges and Perioperative Factors Affecting Delayed Graft Function in Robotic-Assisted Kidney Transplant: A Review of a Single-Center Experience of 100 Cases

Background and objective

The advent of robot-assisted kidney transplant (RAKT) has ushered in a new set of challenges. In this single-center retrospective observational study, we aimed to highlight the anesthetic challenges and analyze perioperative parameters to identify the risk factors for delayed graft function (DGF) in RAKT.

Methods

A descriptive analysis of perioperative factors of the first 100 cases of RAKT at our center was performed. Data were retrieved from the hospital's electronic medical records (EMR) of donors and adult patients who underwent RAKT between July 2015 and December 2020. The data analyzed included demographics, preoperative optimization, intraoperative and postoperative management, and complications. DGF was defined as a requirement of dialysis within one week of transplant. The Fisher’s exact test, independent sample t-test, and the Mann-Whitney test were used to analyze data.

Results

Among a total of 193 renal transplants performed during the study period, 100 patients underwent RAKT, which included 27 females and 73 males. Of these, 91 were live while the remaining involved deceased-donor transplants. Pneumoperitoneum and steep Trendelenburg position required various “anesthetic maneuvers” to maintain hemodynamics and respiratory parameters. Optimal fluid management, with frusemide and mannitol, ensured good urine output (UOP) (93%). Post-reperfusion, the release of pneumoperitoneum, maintenance of adequate perfusion pressures, immunosuppression, and regional hypothermia helped in ensuring adequate graft function (93%). The incidence of DGF in our series was 7% and the mortality rate was 3%. Recipient age (p=0.045), dyslipidemia (p=0.021), and diabetes mellitus (p=0.023) were identified as significant risk factors for DGF.

Conclusion

Advanced recipient age, diabetes, and dyslipidemia were factors significantly associated with DGF in RAKT in our series of 100 cases. However, the duration of the steep Trendelenburg position, docking of robot/pneumoperitoneum (console time), fluid management, warm and cold ischemia times, rewarming time, and type of graft did not influence DGF. Awareness of the systemic involvement in RAKT, proper preoperative optimization, and knowledge of potential problems are essential for the efficient anesthetic management of RAKT.

Nondirected Living Kidney Donation and Recipient Outcomes in the United States: A 20-Year Review

Introduction

Nondirected donation (NDD) of the kidneys is a growing practice where donors who do not have any genetic or emotional relationship are selected to donate to a wide variety of recipients with a range of selection criteria and decisions which are left up to individual transplant centers.

Methods

We review all adult living kidney donor-recipient (DR) pairs and outcomes from NDDs who were recorded in United Network for Organ Sharing (UNOS) database as code 10 (anonymous) from October 1997 to September 2017 for demographics and outcomes.

Results

A total of 2174 DR pairs were identified. The number of NDDs increased from 18 in 2000 to 256 in 2016. Survival analysis showed higher death-censored-graft survival (DC-GS) when recipient was 20 years or more older than donor followed by recipient-donor within 20 years of age and lowest when donor was 20 years or more older than recipient (P = 0.0114).

Conclusion

Overall, the number of NDDs has increased significantly in the 20-year review period. Transplants from NDDs have excellent long-term outcomes. Better matching of controllable DR factors, such as age and body mass index (BMI), could further improve GS. Further research is needed to incorporate these DR factors into paired kidney donation programs potentially enhancing the utility and beneficence of this invaluable donation.

Survival Rate of Renal Transplant and Factors Affecting Renal Transplant Failure

OBJECTIVES

The most important complication in kidney transplant is acute/chronic rejection. In this study, we investigated the factors affecting kidney rejection and transplant survival.

MATERIALS AND METHODS

In this survival analysis study, 352 patients (mean follow-up of 12.9 ± 4.4 years) who underwent renal biopsy due to increased creatinine level from 2012 to 2016 were identified by glomerular filtration rate level and rejection. Probable factors affecting renal function and survival rate after transplant rejection were assessed. P < .05 was considered as significant.

RESULTS

Among our study patients, 40.9% developed early and 59.1% developed late acute kidney injury. Graft survival rates at 1 and 5 years were 98.9% and 68.5%, respectively, which was significant when rejection type was considered (P = .002). In addition, patient survival rates at 1 and 5 years were 99.7% and 98.6%, respectively. Graft survival at 5 years was significantly lower among older subjects, those with diabetes, those who received deceased donor organs, and those with late acute kidney injury (P < .002). Patient survival was significantly higher among young patients, those with systemic lupus erythematosus, those who received living donor organs, and those without cytomegalovirus infection (P < .003).

CONCLUSIONS

We observed that recipient age, type of donor, underlying disease, infection, and late acute kidney injury had great negative impacts on renal dysfunction and survival. In our center, because of the large number of kidney transplants from deceased donors, the necessity of antithymocyte globulin induction therapy was considered, since this study showed that patients who received rabbit antithymocyte globulin induction had better outcomes.

The Association Between Delayed Graft Function and Renal Resistive Index in Kidney Transplant Recipients

Background and objectives

Delayed graft function (DGF) may increase the risk for kidney graft dysfunction. Renal resistive index (RRI) in Doppler ultrasonography is useful in measuring blood flow changes in kidneys which is indicative of tubulointerstitial damage. Most of the diseases in DGF etiology are related to tubulointerstitium and arteries of the kidneys. In this study, we investigated whether there is a relationship between delayed graft function and renal resistive index in kidney transplant recipients (KTR).

Materials and methods

Patients who underwent kidney transplantation were included in this retrospective study. KTR were divided into two groups as DGF (+) and DGF (−). Comparison of RRI values of DGF (+) and DGF (−) groups according to the measurements at different times.

Results

The findings showed that both RRI measurements (post-transplant in the first week and the end of the first year) of the DGF (+) group were higher than DGF (−) group (p=0.001 and p=0.003, respectively). The interaction of measurements and DGF did not have an effect on RRI (p>0.05).

Conclusion

The value of RRI in the DGF (−) group was lower than DGF (+) group in the first week after kidney transplantation.

Estrogen and estrogen receptors in kidney diseases

Acute kidney injury (AKI) and chronic kidney disease (CKD) are posing great threats to global health within this century. Studies have suggested that estrogen and estrogen receptors (ERs) play important roles in many physiological processes in the kidney. For instance, they are crucial in maintaining mitochondrial homeostasis and modulating endothelin-1 (ET-1) system in the kidney. Estrogen takes part in the kidney repair and regeneration via its receptors. Estrogen also participates in the regulation of phosphorus homeostasis via its receptors in the proximal tubule. The ERα polymorphisms have been associated with the susceptibilities and outcomes of several renal diseases. As a consequence, the altered or dysregulated estrogen/ERs signaling pathways may contribute to a variety of kidney diseases, including various causes-induced AKI, diabetic kidney disease (DKD), lupus nephritis (LN), IgA nephropathy (IgAN), CKD complications, etc. Experimental and clinical studies have shown that targeting estrogen/ERs signaling pathways might have protective effects against certain renal disorders. However, many unsolved problems still exist in knowledge regarding the roles of estrogen and ERs in distinct kidney diseases. Further research is needed to shed light on this area and to enable the discovery of pathway-specific therapies for kidney diseases.