Delayed Renal Graft Function: Risk Factors and Impact on the Outcome of Transplantation

Delayed Graft Function in Kidney Retransplantation: United Network for Organ Sharing Data With Linked Primary and Retransplant

INTRODUCTION

There are several articles exploring the risk factors for primary delayed graft function (DGF). However, current literature does not include many resources on the risk factors for DGF when it is a recipient's second kidney transplant or look at short-term graft and patient survival of DGF retransplants.

METHODS

United Network for Organ Sharing data from January 2008 to June 2021 were analyzed. Pancreas transplants, multi-organ transplants, and lost to follow-up transplants were excluded. Second transplant patients with DGF were identified. Multivariate logistic regression models based on the primary and second transplant characteristics were created. Survival analysis was performed with Kaplan-Meier methodology and assessed with log-rank test.

RESULTS

A total of 2964 second kidney transplants were identified. Rate of DGF in the second transplant was 28.4% (843/2964) and 49.2% of them had a prior DGF in their first transplant (P < 0.001). Multivariate analysis confirmed that occurrence of DGF (odds ratio [OR] 1.5, P < 0.001) and graft loss due to acute rejection (OR 1.2, P < 0.005) in the primary transplant were predictors of reappearing DGF in the second transplant. Dialysis at transplant was the greatest risk factor from the second transplant (OR 3.539, P < 0.001). There was a decreased graft survival after 12 mo (77% versus 49% with log t-test <0.001) in the second transplant. However, DGF was not significantly associated with patient survival.

CONCLUSIONS

This study shows the interaction between primary and second transplant in developing DGF. Survival analysis shows lower graft survival for retransplants in the case of DGF. This study opens the possibility of identifying additional risk factors for patients undergoing retransplant surgeries.

Recipient race modifies the association between obesity and long-term graft outcomes after kidney transplantation

Donor and recipient obesity (defined using body mass index [BMI]) are associated with worse outcomes after kidney transplant (KT). In adult KT recipients identified using the Scientific Registry of Transplant Recipients (2000-2017), we examined the modifying effect of recipient race on recipient obesity (BMI > 30 kg/m2) and combined donor and recipient (DR) obesity pairing, with death-censored graft loss (DCGL), all-cause graft loss (ACGL), and short-term graft outcomes using multivariable Cox proportional hazards models and logistic regression. Obesity was associated with a higher risk of DCGL in White (adjusted hazard ratio [aHR], 1.29; 95% CI, 1.25-1.35) than Black (aHR, 1.13; 95% CI, 1.08-1.19) recipients. White, but not Black, recipients with obesity were at higher risk for ACGL (aHR, 1.08; 95% CI, 1.05-1.11, for White recipients; aHR, 0.99; 95% CI, 0.95-1.02, for Black recipients). Relative to nonobese DR, White recipients with combined DR obesity experienced more DCGL (aHR, 1.38; 95% CI, 1.29-1.47 for White; aHR, 1.19; 95% CI, 1.10-1.29 for Black) and ACGL (aHR, 1.12; 95% CI, 1.07-1.17 for White; aHR, 1.00; 95% CI, 0.94-1.07 for Black) than Black recipients. Short-term obesity risk was similar irrespective of race. An elevated BMI differentially affects long-term outcomes in Black and White KT recipients; uniform BMI thresholds to define transplant eligibility are likely inappropriate.

Transplanting a left or right donor kidney into the left or right iliac fossa: importance of laterality and site of venous anastomosis

Data on the impact of donor-to-recipient laterality on kidney transplantation are lacking. This study evaluated the impact of donor-to-iliac fossa laterality and the site of venous anastomosis on operating time and surgical outcome. This retrospective single-center study analyzed 1262 deceased donor adult kidney transplants into pristine iliac fossa. Multivariable linear and logistic regression analyses were used to identify variables with an impact on operating time and surgical complications. Operating time was shorter by 11 min in median for transplantations into the right iliac fossa compared to the left iliac fossa (p < 0.001). Operating time in left-to-right donor-to-recipient combination was shorter by 17 min in median if venous anastomoses were performed on the caval vein or common iliac vein as compared to anastomoses to the external iliac vein (p < 0.001). Overall, the shortest operating times (median 112.5 min) were achieved in left-to-right donor-to-recipient combinations with venous anastomosis to the caval or common iliac vein, without an increase in surgical complications. Kidney transplantation into the right iliac fossa with anastomosis to the caval vein or the common iliac vein saves operating time and reduces thrombotic complications. Acceptance of a left donor kidney is likely to further reduce operating time.

Combined Donor-Recipient Obesity and the Risk of Graft Loss After Kidney Transplantation

Background: As the prevalence of obesity increases globally, appreciating the effect of donor and recipient (DR) obesity on graft outcomes is of increasing importance. Methods: In a cohort of adult, kidney transplant recipients (2000-2017) identified using the SRTR, we used Cox proportional hazards models to examine the association between DR obesity pairing (body mass index (BMI) >30 kg/m2), and death-censored graft loss (DCGL) or all-cause graft loss, and logistic regression to examine risk of delayed graft function (DGF) and ≤30 days graft loss. We also explored the association of DR weight mismatch (>30 kg, 10-30 kg (D>R; D Collapse

Key Words

• body mass index
• graft loss
• kidney transplant outcomes
• obesity
• obesity pairing
• weight mismatch

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MESH Headings

• Adult
• Cohort Studies
• Graft Rejection/epidemiology
• Humans
• Kidney Transplantation/adverse effects
• Obesity/epidemiology
• Risk Factors
• Tissue Donors/statistics & numerical data
• Transplant Recipients/statistics & numerical data
• Treatment Outcome

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Affiliation(s)

Faisal Jarrar Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
Karthik K. Tennankore Faculty of Medicine, Dalhousie University, Halifax, NS, Canada Division of Nephrology, Department of Medicine, Nova Scotia Health Authority, Halifax, NS, Canada
Amanda J. Vinson Faculty of Medicine, Dalhousie University, Halifax, NS, Canada Division of Nephrology, Department of Medicine, Nova Scotia Health Authority, Halifax, NS, Canada

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Development and Validation of Nomogram for Predicting Delayed Graft Function After Kidney Transplantation of Deceased Donor

Background

Delayed graft function (DGF) is a major complication of kidney transplantation (KT), especially in patients receiving donor of decease (DD) KT. Therefore, the kidney donor pool is rare worldwide, it is critical to evaluate the risk coefficient of DGF using preoperative data of donors and recipients and provide a reference for clinical decision-making and resource allocation.

Method and Analysis

A total of 238 DD recipients were performed in our center. Finally, 211 patients were included. The clinical database was divided into 34 clinical blood indicators (CBIs) and 6 demographics indexes (DIs). CBIs and DIs were screened for variables with P<0.05 and demonstrated the best cut-off value using multivariable logistics regression. The selected CBIs were passed through the least absolute shrinkage and selection operator (LASSO) to obtain the predictive factors and synthesized into a Riskscore, forming a nomogram with the selected DIs. We used receiver operating characteristic (ROC), calibration, and decision curve analysis (DCA) to verify the discrimination and clinical effects of this nomogram. Finally, 10-fold cross-validation was conducted internally to show the effect of the model.

Results

The 34 CBIs of the database finally screened out 12 predictors, which were synthesized into Riskscore. The 6 DIs selected 3 variables. Riskscore and 3 DIswere constructed into a nomogram, and the ROC of the nomogram has an AUC value of 0.725. Calibration and DCA showed excellent verification effects on the nomogram. The 10-fold crossover internal validation also demonstrated the model’s excellent discrepancy.

Conclusion

The nomogram has an excellent ability to predict DGF and provides an essential reference for decision-making and resource allocation in a clinical setting.

Description and Outcomes of Three Different End-to-Side Microsurgical Techniques for the Anastomosis of Accessory Renal Artery With the Dominant Renal Artery in Kidney Transplantation

BACKGROUND

In this study, we compared the outcomes of three different surgical microscope-assisted end-to-side anastomosis techniques between the dominant and accessory renal arteries during living donor kidney transplant.

METHODS

The demographics, serum creatinine levels, warm and cold ischemia times, rate of complications, and incidence of delayed graft function of 135 kidney recipients were analyzed according to the type of arterial anastomosis. Group A (n = 98) had one dominant renal artery (DRA) with one end-to-side anastomosis to the external iliac artery (EIA) using a surgical microscope. Group B (n = 17) had one DRA plus one accessory renal artery (ARA) with two separate end-to-side anastomoses to the EIA using a surgical microscope. Group C (n = 20) had one DRA with end-to-side anastomosis to the EIA and one ARA with an ex vivo on-bench end-to-side anastomosis to the DRA using a surgical microscope.

RESULTS

Compared with groups A and B, the cold ischemia time and the rate of delayed graft function were significantly higher in group C (P ≤ .001). At 6 months after transplant, group B demonstrated a higher creatinine value (2.40 ± 3.41 mg/dL) than group A and group B (P = .032). Also, the decrease in creatinine at postoperative month 6 was limited in group B as compared with groups A and C.

CONCLUSIONS

An end-to-side anastomosis between ARA (group B) and DRA (group A) of the kidney graft using a surgical microscope on the bench ex vivo results in superior outcomes. Single arterial anastomosis techniques are associated with a better function in a 6-month follow-up than two separate arterial anastomoses.

Prolonged warm ischemia time leads to severe renal dysfunction of donation-after-cardiac death kidney grafts

Kidney transplantation with grafts procured after donation-after-cardiac death (DCD) has led to an increase in incidence of delayed graft function (DGF). It is thought that the warm ischemic (WI) insult encountered during DCD procurement is the cause of this finding, although few studies have been designed to definitely demonstrate this causation in a transplantation setting. Here, we use a large animal renal transplantation model to study the effects of prolonged WI during procurement on post-transplantation renal function. Kidneys from 30 kg-Yorkshire pigs were procured following increasing WI times of 0 min (Heart-Beating Donor), 30 min, 60 min, 90 min, and 120 min (n = 3-6 per group) to mimic DCD. Following 8 h of static cold storage and autotransplantation, animals were followed for 7-days. Significant renal dysfunction (SRD), resembling clinical DGF, was defined as the development of oliguria < 500 mL in 24 h from POD3-4 along with POD4 serum potassium > 6.0 mmol/L. Increasing WI times resulted in incremental elevation of post-operative serum creatinine that peaked later. DCD120min grafts had the highest and latest elevation of serum creatinine compared to all groups (POD5: 19.0 ± 1.1 mg/dL, p < 0.05). All surviving animals in this group had POD4 24 h urine output < 500 cc (mean 235 ± 172 mL) and elevated serum potassium (7.2 ± 1.1 mmol/L). Only animals in the DCD120min group fulfilled our criteria of SRD (p = 0.003), and their renal function improved by POD7 with 24 h urine output > 500 mL and POD7 serum potassium < 6.0 mmol/L distinguishing this state from primary non-function. In a transplantation survival model, this work demonstrates that prolonging WI time similar to that which occurs in DCD conditions contributes to the development of SRD that resembles clinical DGF.

Early morning kidney transplantation: Perioperative complications

INTRODUCTION

To reduce cold ischemia time (CIT), many kidney transplants are performed in the early morning. Conducting complex surgeries in the early morning may influence the surgeon's technical capacity and rate of surgical complications (SC).

AIM

Evaluate the influence of surgery start hour (SSH) regarding duration of surgery (DS), immediate diuresis (ID), SC and acute rejection (AR); evaluate the influence of CIT regarding SC, ID, and AR.

METHODS

2855 cadaveric transplants performed between June 1980 and March 2018 were retrospectively evaluated. Regarding SSH, two groups were created: Group M (00: 00h-05.59h, n = 253) and Group D (06: 00h - 23: 59h, n = 2602). Analyzing the impact of SSH on DS, ID, SC and AR. Evaluate the relationship between CIT (< 18h, 18-30h and > 30h) on ID, SC and AR utilizing univariate and multivariate statistical analysis with SPSS.

RESULTS AND CONCLUSION

Groups M and D were comparable in all evaluated demographic variables (p > 0.05), except cold ischemia time (Group M with higher CIT, p < 0.001). Regarding univariate analysis, Surgery start hour did not influence DS (p = 0.344), and SC (p = 0.264), but related with higher ID (p = 0.028) and AR (p = 0.018). CIT related with immediate diuresis (p = 0.020) and acute rejection (p < 0.001) but did not relate with complications (p = 0.734). Regarding multivariate analysis, SSH only influenced immediate diuresis (p = 0.026) and did not influenced acute rejection (p = 0.055). CIT influenced immediate diuresis (p = 0.019) and acute rejection (p < 0.001). Surgery start hour influences Immediate diuresis. With this study, we conclude that the priority must be a short cold ischemia time.

Vasopressor selection during critical care management of brain dead organ donors and the effects on kidney graft function

BACKGROUND

Delayed graft function (DGF), the need for dialysis in the first week following kidney transplant, affects approximately one quarter of deceased-donor kidney transplant recipients. Donor demographics, donor serum creatinine, and graft cold ischemia time are associated with DGF. However, there is no consensus on the optimal management of hemodynamic instability in organ donors after brain death (DBDs). Our objective was to determine the relationship between vasopressor selection during donor management and the development of DGF.

METHODS

Prospective observational data, including demographic and critical care parameters, were collected for all DBDs managed by 17 organ procurement organizations from nine Organ Procurement and Transplantation Network Regions between 2012 and 2018. Recipient outcome data were linked with donor data through donor identification numbers. Donor critical care parameters, including type of vasopressor and doses, were recorded at three standardized time points during donor management. The analysis included only donors who received at least one vasopressor at all three time points. Vasopressor doses were converted to norepinephrine equivalent doses and analyzed as continuous variables. Univariate analyses were conducted to determine the association between donor variables and DGF. Results were adjusted for known predictors of DGF using binary logistic regression.

RESULTS

Complete data were available for 5,554 kidney transplant recipients and 2,985 DBDs. On univariate analysis, donor serum creatinine, donor age, donor subtype, kidney donor profile index, graft cold ischemia time, phenylephrine dose, and dopamine dose were associated with DGF. After multivariable analysis, increased donor serum creatinine, donor age, kidney donor profile index, graft cold ischemia time, and phenylephrine dose remained independent predictors of DGF.

CONCLUSION

Higher doses of phenylephrine were an independent predictor of DGF. With the exception of phenylephrine, the selection and dose of vasopressor during donor management did not predict the development of DGF.

LEVEL OF EVIDENCE

Prognostic study, Level III.

Significant Improvement in Rat Kidney Cold Storage Using UW Organ Preservation Solution Supplemented With the Immediate-Acting PrC-210 Free Radical Scavenger

Ischemia-reperfusion injury, including injury from warm- and cold-ischemia (CI) organ storage, remains a significant problem for all solid organ transplants. Suppressing CI damage would reduce delayed graft function and increase the donor organ pool size. PrC-210 has demonstrated superior prevention of damage in several preclinical studies as an immediate-acting free-radical scavenger. Here, we describe its profound efficacy in suppressing CI injury in a rat kidney model.

Identification of Factors Associated With Acute Tubular Necrosis Following Kidney Transplant in Northern Mexico: Increased Risk With Cold Ischemia After 8 Hours

AIM

To identify potential risk factors associated with the incidence of acute tubular necrosis (ATN) following kidney transplant in a sample of patients from northern Mexico.

METHODS

Secondary analysis of data extracted from clinical files of patients who underwent a kidney transplant between 2000 and 2017 at Christus Muguerza Hospital in the city of Chihuahua. The final sample with complete data included 485 patients. ATN was diagnosed in 13.2% of patients using pathologic, clinical, and laboratory criteria. Adjusted odds ratio (ORs) with 95% CIs from multivariate binary logistic regression were used to identify predictors of ATN.

RESULTS

Only 4 of 21 variables analyzed remained statistically significant in the final adjusted model. Cold and warm ischemia followed time-trend patterns with higher odds with longer ischemia times. For cold ischemia, compared with 0 to 240 minutes, ORs were 1.32 (95% CI, 0.49-3.51) for 241-480 minutes, 4.87 (95% CI, 2.29-10.3) for 481-960 minutes, and 10.0 (95% CI, 2.86-35.0) for > 960 minutes; for warm ischemia, compared with 40 to 59 minutes, these were 6.27 (95% CI, 1.95-20.8) for 60-70 minutes and 10.32 (95% CI, 1.95-54.4) for 71-110 minutes. Hypotension during surgery was associated with a higher chance of ATN (OR, 15.9; 95% CI, 4.97-50.9). When the recipients' age was 30 years or older, the probability also increased significantly (OR, 2.88; 95% CI, 1.09-7.57). The final model fitted well and explained 27% of the probability to develop ATN after a kidney transplant.

CONCLUSION

Shortening the duration of ischemia and avoiding hypotension during surgery is essential to prevent ATN following a kidney transplant.

Significant Reduction of Murine Renal Ischemia-Reperfusion Cell Death Using the Immediate-Acting PrC-210 Reactive Oxygen Species Scavenger

Background.

Ischemia-reperfusion (IR) injury remains a significant problem for all solid organ transplants; thus, an important unmet need in transplantation is the prevention of IR injury. PrC-210 has demonstrated superior prevention of reactive oxygen species damage in several preclinical studies as a free radical scavenger. Here, we describe its profound efficacy in suppressing IR injury in a murine model of kidney IR injury.

Methods.

C57/B6 mice underwent laparotomy with the left renal pedicle occluded for 30 minutes to induce IR injury. Right nephrectomy was performed at the time of surgery. Mice received a single systemic dose of the PrC-210, PrC-211, or PrC-252 aminothiols 20 minutes before IR injury. Twenty-four hours following IR injury, blood and kidney tissue were collected for analysis. Kidney caspase-3 level (a marker of cell death), direct histological analysis of kidneys, and serum blood urea nitrogen (BUN) were measured in animals to assess reactive oxygen species scavenger protective efficacies.

Results.

A single systemic PrC-210 dose 20 minutes before IR injury resulted in significant reductions in (1) IR-induced kidney caspase level (P < 0.0001); caspase was reduced to levels not significantly different than control caspase levels seen in unperturbed kidneys, (2) IR-induced renal tubular injury scores (P < 0.0001); brush border loss and tubular dilation were markedly reduced, and (3) serum BUN compared with control IR injury kidneys (P < 0.0001). The ranked protective efficacies of PrC-210 > PrC-211 >> PrC-252 paralleled previous radioprotection studies of the molecules.

Conclusions.

A single PrC-210 dose, minutes before the IR insult, profoundly reduced caspase, renal tubular injury, and serum BUN in mice exposed to standard kidney IR injury. These findings support further development of the PrC-210 molecule to suppress or prevent IR injury in organ transplant and other IR injury settings.

Risk Balancing of Cold Ischemic Time against Night Shift Surgery Possibly Reduces Rates of Reoperation and Perioperative Graft Loss

Background. This retrospective cohort study evaluates the advantages of risk balancing between prolonged cold ischemic time (CIT) and late night surgery. Methods. 1262 deceased donor kidney transplantations were analyzed. Multivariable regression was used to determine odds ratios (ORs) for reoperation, graft loss, delayed graft function (DGF), and discharge on dialysis. CIT was categorized according to a forward stepwise pattern ≤1h/>1h, ≤2h/>2h, ≤3h/>3h,…, ≤nh/>nh. ORs for DGF were plotted against CIT and a nonlinear regression function with best R² was identified. First and second derivative were then implemented into the curvature formula k(x) = f′′(x)/(1 + f′(x)²)^3/2 to determine the point of highest CIT-mediated risk acceleration. Results. Surgery between 3 AM and 6 AM is an independent risk factor for reoperation and graft loss, whereas prolonged CIT is only relevant for DGF. CIT-mediated risk for DGF follows an exponential pattern f(x) = A · (1 + k · e^{(I · x)}) with a cut-off for the highest risk increment at 23.5 hours. Conclusions. The risk of surgery at 3 AM–6 AM outweighs prolonged CIT when confined within 23.5 hours as determined by a new mathematical approach to calculate turning points of nonlinear time related risks. CIT is only relevant for the endpoint of DGF but had no impact on discharge on dialysis, reoperation, or graft loss.

Prediction, prevention, and management of delayed graft function: where are we now?

Delayed graft function (DGF) remains a major barrier to improved outcomes after kidney transplantation. High-risk transplant recipients can be identified, but no definitive prediction model exists. Novel biomarkers to predict DGF in the first hours post-transplant, such as neutrophil gelatinase-associated lipocalin (NGAL), are under investigation. Donor management to minimize the profound physiological consequences of brain death is highly complex. A hormonal resuscitation package to manage the catecholamine "storm" that follows brain death is recommended. Donor pretreatment with dopamine prior to procurement lowers the rate of DGF. Hypothermic machine perfusion may offer a significant reduction in the rate of DGF vs simple cold storage, but costs need to be evaluated. Surgically, reducing warm ischemia time may be advantageous. Research into recipient preconditioning options has so far not generated clinically helpful interventions. Diagnostic criteria for DGF vary, but requirement for dialysis and/or persistent high serum creatinine is likely to remain key to diagnosis until current work on early biomarkers has progressed further. Management centers on close monitoring of graft (non)function and physiological parameters. With so many unanswered questions, substantial reductions in the toll of DGF in the near future seem unlikely but concentrated research on many levels offers long-term promise.

Delayed Graft Function in Kidney Transplantation

Context:

Although kidney transplantations are routinely performed at many centers in Turkey, the incidence and risk factors associated with delayed graft function (DGF) here have not yet been well defined.

Objective:

The aim of this study is to evaluate the incidence and risk factors of DGF and its impact on early graft function.

Design:

The medical charts of 154 adult patients who underwent deceased donor kidney transplantation between 2000 and 2014 in a single center were reviewed retrospectively.

Setting:

Delayed graft function-related risk factors for donors, recipients, and the transplant surgery itself were analyzed, and their relation with graft function was evaluated.

Main Outcomes Measures:

The median recipient age was 39 years. The median cold ischemia time (CIT) was 840 minutes (14 hours). The incidence of DGF and acute rejection were 57.8% and 8.4%, respectively. Higher serum creatinine levels at 3, 6, and 12 months were observed in patients with DGF compared to other patients without DGF ( P < .05). Patients with DGF had poor graft function (glomerular filtration rate ≤ 50) at 3 and 6 months ( P < .05), but these correlations were not seen at 12 months ( P = not significant).

Results:

This study showed that DGF was a common and serious problem associated with poor graft functions at 3, 6, and 12 months after transplantation. Extra effort to shorten CIT as an independent risk factor for DGF could have protective effect on graft functions.

Risk factors and long-term outcomes of delayed graft function in deceased donor renal transplantation

Purpose

The purpose of this study was to analyze the risk factors for delayed graft function (DGF) and determine its impact on the outcomes of deceased donor (DD) kidney transplantation (KT).

Methods

Between January 2000 and December 2011, we performed 195 DD renal transplants. After the exclusion of primary nonfunctional grafts (n = 4), the study recipients were divided into two groups-group I, DGF (n = 31, 16.2%); group II, non-DGF (n = 160, 83.8%). The following variables were compared: donor and recipient characteristics, patient and graft survival, postoperative renal function, acute rejection (AR) episodes, and the rates of surgical and infectious complications.

Results

Donor-related variables that showed significant differences included hypertension (P = 0.042), diabetes (P = 0.025), and prerecovery serum creatinine levels (P < 0.001). However, there were no significant differences in recipient-related factors. One significantly different transplant-related factor was positive panel reactive antibody (PRA > 20%, P = 0.008). On multivariate analysis, only the prerecovery serum creatinine level (P < 0.001; hazard ratio [HR], 1.814) was an independent risk factor for the development of DGF. A Cox multivariate analysis of risk factors for graft survival identified these independent risk factors for graft survival: nephron mass (donor kidney weight to recipient body weight ratio) index (P = 0.026; HR, 2.328), CMV infection (P = 0.038; HR, 0.114), and AR episode (P = 0.038; HR, 0.166).

Conclusion

In DD KT, an independent risk factor for DGF was the prerecovery serum creatinine level. Although there was a significant difference in graft survival between the DGF and non-DGF groups, DGF was not an independent risk factor for graft failure in this study.

Predictive model for delayed graft function based on easily available pre-renal transplant variables

Identification of pre-transplant factors influencing delayed graft function (DGF) could have an important clinical impact. This could allow clinicians to early identify dialyzed chronic kidney disease (CKD) patients eligible for special transplant programs, preventive therapeutic strategies and specific post-transplant immunosuppressive treatments. To achieve these objectives, we retrospectively analyzed main demographic and clinical features, follow-up events and outcomes registered in a large dedicated dataset including 2,755 patients compiled collaboratively by four Italian renal/transplant units. The years of transplant ranged from 1984 to 2012. Statistical analysis clearly demonstrated that some recipients' characteristics at the time of transplantation (age and body weight) and dialysis-related variables (modality and duration) were significantly associated with DGF development (p ≤ 0.001). The area under the receiver-operating characteristic (ROC) curve of the final model based on the four identified variables predicting DGF was 0.63 (95 % CI 0.61, 0.65). Additionally, deciles of the score were significantly associated with the incidence of DGF (p value for trend <0.001). Therefore, in conclusion, in our study we identified a pre-operative predictive model for DGF, based on inexpensive and easily available variables, potentially useful in routine clinical practice in most of the Italian and European dialysis units.

Factors affecting eGFR 5-year post-deceased donor renal transplant: analysis and predictive model

AIM

Long-term survival of renal allografts has improved over the last 20 years. However, less is known about current expectations for long-term allograft function as determined by estimated glomerular filtration rate (eGFR). The aim of this study was to investigate factors which affect graft function at 5 years' post-renal transplantation. The statistically significant factors were then used to construct a predictive model for expected eGFR at five years' post-transplant.

METHODS

We retrospectively reviewed all adult patients who received a renal transplant in the Republic of Ireland between 1990 and 2004. Data collected included era of transplantation (1990-1994, 1995-1999, 2000-2004), donor and recipient age and gender, number of human leucocyte antigen mismatches, cold ischemia time (CIT), number of prior renal transplants, immunosuppressive regimen used and acute rejection episodes. Estimated GFR was calculated at 5 years after transplantation from patient data using the Modified Diet in Renal Disease (MDRD) equation. Consecutive sampling was used to divide the study population into two equal unbiased groups of 489 patients. The first group (derivation cohort) was used to construct a predictive model for eGFR five years' post-transplantation, the second (validation cohort) to test this model.

RESULTS

Nine hundred and seventy eight patients were analyzed. The median age at transplantation was 43 years (range 18-78) and 620 (63.4%) were male. One hundred and seventy five patients (17.9%) had received a prior renal transplant. Improved eGFR at five years' post-transplantation was associated with tacrolimus-based combination immunosuppression, younger donor age, male recipient, absence of cytomegalovirus disease and absence of acute rejection episodes as independently significant factors (p < 0.05). The predictive model developed using these factors showed good correlation between predicted and actual median eGFR at five years. The model explained 20% of eGFR variability. The validation model findings were consistent with the derivation model (21% variability of eGFR explained by model using same covariates on new data).

CONCLUSION

The predictive model we have developed shows good correlation between predicted and actual median eGFR at five years' post-transplant. Applications of this model include comparison of current and future therapy options such as new immunosuppressive regimens.

Do we need a different organ allocation system for kidney transplants using donors after circulatory death?

BACKGROUND

There is no national policy for allocation of kidneys from Donation after circulatory death (DCD) donors in the UK. Allocation is geographical and based on individual/regional centre policies. We have evaluated the short term outcomes of paired kidneys from DCD donors subject to this allocation policy.

METHODS

Retrospective analysis of paired renal transplants from DCD's from 2002 to 2010 in London. Cold ischemia time (CIT), recipient risk factors, delayed graft function (DGF), 3 and 12 month creatinine) were compared.

RESULTS

Complete data was available on 129 paired kidneys.115 pairs were transplanted in the same centre and 14 pairs transplanted in different centres. There was a significant increase in CIT in kidneys transplanted second when both kidneys were accepted by the same centre (15.5 ± 4.1 vs 20.5 ± 5.8 hrs p<0.0001 and at different centres (15.8 ± 5.3 vs. 25.2 ± 5.5 hrs p=0.0008). DGF rates were increased in the second implant following sequential transplantation (p=0.05).

CONCLUSIONS

Paired study sequential transplantation of kidneys from DCD donors results in a significant increase in CIT for the second kidney, with an increased risk of DGF. Sequential transplantation from a DCD donor should be avoided either by the availability of resources to undertake simultaneous procedures or the allocation of kidneys to 2 separate centres.

Gene expression profile in delay graft function: inflammatory markers are associated with recipient and donor risk factors

Background. Delayed graft function (DGF) remains an important problem after kidney transplantation and reduced long-term graft survival of the transplanted organ. The aim of the present study was to determine if the development of DGF was associated with a specific pattern of inflammatory gene expression in expanded criteria of deceased donor kidney transplantation. Also, we explored the presence of correlations between DGF risk factors and the profile that was found. Methods. Seven days after kidney transplant, a cDNA microarray was performed on biopsies of graft from patients with and without DGF. Data was confirmed by real-time PCR. Correlations were performed between inflammatory gene expression and clinical risk factors. Results. From a total of 84 genes analyzed, 58 genes were upregulated while only 1 gene was downregulated in patients with DGF compared with no DGF (P = 0.01). The most relevant genes fold changes observed was IFNA1, IL-10, IL-1F7, IL-1R1, HMOX-1, and TGF-β. The results were confirmed for IFNA1, IL-1R1, HMOX-1 and TGF-β. A correlation was observed between TGF-β, donor age, and preablation creatinine, but not body mass index (BMI). Also, TGF-β showed an association with recipient age, while IFNA1 correlated with recipient BMI. Furthermore, TGF-β, IFNA1 and HMOX-1 correlated with several posttransplant kidney function markers, such as diuresis, ultrasound Doppler, and glycemia. Conclusions. Overall, the present study shows that DGF is associated with inflammatory markers, which are correlated with donor and recipient DGF risk factors.

Karyopherins: potential biological elements involved in the delayed graft function in renal transplant recipients

Background

Immediately after renal transplantation, patients experience rapid and significant improvement of their clinical conditions and undergo considerable systemic and cellular modifications. However, some patients present a slow recovery of the renal function commonly defined as delayed graft function (DGF). Although clinically well characterized, the molecular mechanisms underlying this condition are not totally defined, thus, we are currently missing specific clinical markers to predict and to make early diagnosis of this event.

Methods

We investigated, using a pathway analysis approach, the transcriptomic profile of peripheral blood mononuclear cells (PBMC) from renal transplant recipients with DGF and with early graft function (EGF), before (T0) and 24 hours (T24) after transplantation.

Results

Bioinformatics/statistical analysis showed that 15 pathways (8 up-regulated and 7 down-regulated) and 11 pathways (5 up-regulated and 6 down-regulated) were able to identify DGF patients at T0 and T24, respectively. Interestingly, the most up-regulated pathway at both time points was NLS-bearing substrate import into nucleus, which includes genes encoding for several subtypes of karyopherins, a group of proteins involved in nucleocytoplasmic transport. Signal transducers and activators of transcription (STAT) utilize karyopherins-alpha (KPNA) for their passage from cytoplasm into the nucleus. In vitro functional analysis demonstrated that in PBMCs of DGF patients, there was a significant KPNA-mediated nuclear translocation of the phosphorylated form of STAT3 (pSTAT3) after short-time stimulation (2 and 5 minutes) with interleukin-6.

Conclusions

Our study suggests the involvement, immediately before transplantation, of karyopherin-mediated nuclear transport in the onset and development of DGF. Additionally, it reveals that karyopherins could be good candidates as potential DGF predictive clinical biomarkers and targets for pharmacological interventions in renal transplantation. However, because of the low number of patients analyzed and some methodological limitations, additional studies are needed to validate and to better address these points.

Role of Toll-like receptor-4 in renal graft ischemia-reperfusion injury

Toll-like receptor-4 (TLR-4) has been increasingly recognized as playing a critical role in the pathogenesis of ischemia-reperfusion injury (IRI) of renal grafts. This review provides a detailed overview of the new understanding of the involvement of TLR-4 in ischemia-reperfusion injury of renal grafts and its clinical significance in renal transplantation. TLR-4 not only responds to exogenous microbial motifs but can also recognize molecules which are released by stressed and necrotic cells, as well as degraded products of endogenous macromolecules. Upregulation of TLR-4 is found in tubular epithelial cells, vascular endothelial cells, and infiltrating leukocytes during renal ischemia-reperfusion injury, which is induced by massive release of endogenous damage-associated molecular pattern molecules such as high-mobility group box chromosomal protein 1. Activation of TLR-4 promotes the release of proinflammatory mediators, facilitates leukocyte migration and infiltration, activates the innate and adaptive immune system, and potentiates renal fibrosis. TLR-4 inhibition serves as the target of pharmacological agents, which could attenuate ischemia-reperfusion injury and associated delayed graft function and allograft rejection. There is evidence in the literature showing that targeting TLR-4 could improve long-term transplantation outcomes. Given the pivotal role of TLR-4 in ischemia-reperfusion injury and associated delayed graft function and allograft rejection, inhibition of TLR-4 using pharmacological agents could be beneficial for long-term graft survival.

Surgical complications and graft survival in pediatric kidney transplant recipients treated with a steroid-free protocol: experiences from a Danish university hospital

BACKGROUND

The outcome of pediatric kidney transplantation depends on several factors, among these are the complications, which occur in relation to the surgical procedure. In this study, we present our experience with pediatric kidney transplantation in a steroid-free immunosuppression regimen, from a surgical point of view.

METHODS

Patient charts of pediatric kidney transplantations in the period 1998-2011 were reviewed. Surgical complications, acute rejection, and patient and graft survivals were recorded.

RESULTS

Sixty-one renal transplantations were performed in 58 patients. Thirty patients (49.1%) experienced a surgical complication, of which 11 (18%) required an explorative laparotomy. Overall the five-year Kaplan-Meier patient survival rate was 96.2% and the graft survival rate was 88.6%. Nine patients (14.7%) had an acute rejection episode within the first year after transplantation. No correlation was observed between surgical complications and acute rejection episodes or graft loss.

CONCLUSIONS

This study indicated a high incidence of surgical complications among pediatric kidney transplantations when using a steroid-free immunosuppression regimen. Despite this, we observed high overall patient and graft survival, supporting the trend toward steroids avoidance in pediatric kidney transplantation.

The impact of recipient obesity on outcomes after renal transplantation

BACKGROUND

The benefit of renal transplantation in obese patients is controversial, with many centers setting upper limits on body mass index (BMI) in consideration for listing patients for transplant. This study was undertaken to determine the effect of recipient obesity on delayed graft function (DGF) and graft survival after renal transplantation.

METHODS

Retrospective review of all renal transplant recipients in the United Network for Organ Sharing database from January 1, 2004, through December 31, 2009, was performed. Primary endpoints were DGF and non-death-censored graft survival. Comparisons were made on the basis of the following weight classes: nonobese (BMI < 30), class I obese (30 ≤ BMI < 35), class II obese (35 ≤ BMI < 40), and class III obese (BMI ≥ 40).

RESULTS

Multivariable logistic regression indicated a significantly increased risk for DGF in obese patients. The odds ratios for DGF compared with nonobese patients were 1.34 [95% confidence interval (CI) 1.27-1.42; P < 0.001], 1.68 (95% CI 1.56-1.82; P < 0.001), and 2.68 (95% CI 2.34-3.07; P < 0.001) for the class I obese, class II obese, and class III obese groups, respectively. Class I obesity was not a significant risk for non-death-censored graft failure [hazard ratio (HR) 1.00, 95% CI 0.95-1.05; P = 0.901] compared with nonobese patients. Patients in the class II obese (HR 1.15, 95% CI 1.07-1.24; P < 0.001) and class III obese (HR 1.26, 95% CI 1.11-1.43; P < 0.001) groups were at a significantly increased risk for graft failure than their nonobese counterparts.

CONCLUSIONS

Obese patients in all weight classes are at an increased risk for DGF after renal transplantation, although differences in non-death-censored graft survival are such that transplantation should not be denied on the basis of BMI criteria alone.

Delayed graft function and long-term outcome in kidney transplantation

BACKGROUND

There are still many controversies about the impact of delayed graft function (DGF) on kidney transplantation outcome. The aims of this study were to define factors associated with DGF and to ascertain the relative impact of DGF on kidney transplantation outcome, both in the early postoperative period and in long-term follow-up.

PATIENTS AND METHODS

Four hundred kidney transplant recipients were reviewed to assess the clinical impact of DGF on long-term outcome.

RESULTS

The overall prevalence of DGF was 24.3%. DGF was significantly associated with increasing recipient and donor age, duration of dialysis, and cold ischemia time. Patients with DGF displayed a significantly worse graft (P = .005) and patient (P < .001) survival compared with recipients with immediate function.

CONCLUSION

DGF is a frequent complication of renal transplantation and may be associated with a reduced graft and even patient survival. Strategies to prevent graft injury and, more specifically, DGF may be an important clue to provide a better long-term outcome in kidney transplantation.

Efficacy and safety of thymoglobulin and basiliximab in kidney transplant patients at high risk for acute rejection and delayed graft function

OBJECTIVES

To compare the efficacy and safety of thymoglobulin compared with basiliximab in patients who had kidney transplants and are at high risk for acute rejection and delayed graft function.

MATERIALS AND METHODS

A retrospective review of patients who had 1 or more risk factors for acute rejection and delayed graft function and who were given either thymoglobulin or basiliximab for induction therapy. Incidences of acute rejection, antibody-treated acute rejection, delayed graft function, chronic rejection, cancer, infection, leucopenia, and thrombocytopenia were compared between thymoglobulin and basiliximab groups. Serum creatinine levels within 1 year and long-term graft and patient survival also were compared.

RESULTS

A total of 327 patients were included. Incidences of acute rejection, antibody-treated acute rejection, delayed graft function, and chronic rejection were significantly lower in the thymoglobulin group than in the basiliximab group (P < .05). Serum creatinine levels were lower in the thymoglobulin group on postoperative days 7, 14, and 30 (P < .05). There were no statistically significant differences regarding long-term graft and patient survival, cancer, or total infection rate between the groups. Incidences of Cytomegalovirus infection, leucopenia, and thrombocytopenia were significantly higher in the thymoglobulin group (P < .05).

CONCLUSIONS

Thymoglobulin may improve short-term outcomes, compared with basiliximab, in patients who had kidney transplants and are at high risk for acute rejection and delayed graft function. However, long-term outcomes are similar with thymoglobulin and basiliximab.

Early outcome in renal transplantation from large donors to small and size-matched recipients - a porcine experimental model

Kidney transplantation from a large donor to a small recipient, as in pediatric transplantation, is associated with an increased risk of thrombosis and DGF. We established a porcine model for renal transplantation from an adult donor to a small or size-matched recipient with a high risk of DGF and studied GFR, RPP using MRI, and markers of kidney injury within 10 h after transplantation. After induction of BD, kidneys were removed from ∼63-kg donors and kept in cold storage for ∼22 h until transplanted into small (∼15 kg, n = 8) or size-matched (n = 8) recipients. A reduction in GFR was observed in small recipients within 60 min after reperfusion. Interestingly, this was associated with a significant reduction in medullary RPP, while there was no significant change in the size-matched recipients. No difference was observed in urinary NGAL excretion between the groups. A significant higher level of HO-1 mRNA was observed in small recipients than in donors and size-matched recipients indicating cortical injury. Improvement in early graft perfusion may be a goal to improve short- and long-term GFR and avoid graft thrombosis in pediatric recipients.