Association Between Slow and Delayed Graft Function With Graft Outcomes in Pediatric and Adolescent Deceased Donor Kidney Transplant Recipients

The Differential Impact of Early Graft Dysfunction in Kidney Donation After Brain Death and After Circulatory Death: Insights from the Dutch National Transplant Registry

Kidneys donated after circulatory death (DCD) perform similarly to kidneys donated after brain death (DBD). However, the respective incidences of delayed graft function (DGF) differ. This questions the donor type-specific impact of early graft function on long-term outcome. Using competing risk and cox regression analysis, we compared death-censored graft loss between types of early graft function: DGF (temporary dialysis dependency started within seven days after transplantation), slow graft function (SGF, three-day plasma creatinine decline less than 10% per day), and immediate graft function (IGF). In 1061 DBD and 1605 DCD graft recipients (January 2014 until January 2023), graft survival was similar. DGF was associated with death-censored graft loss in DBD and DCD (adjusted hazard ratios [aHR]: DGF in DBD: 1.79 [1.04- 2.91], p = 0.027, DGF in DCD: 1.84 [1.18 - 2.87], p = 0.008; Reference: no DGF). SGF was associated with death-censored graft loss in DBD, but not significantly in DCD (aHR DBD: 2.82 (1.34 - 5.93), p = 0.007, and DCD: 1.54 (0.72 - 3.35), p = 0.262; Reference: IGF). Early graft dysfunction has a differential impact on graft outcome in DBD and DCD. The differences between DBD and DCD should be accounted for in research and the clinic.

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

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

The Outcome of Transplanting Kidneys From Very Small Pediatric Deceased Donors

BACKGROUND

Kidneys from very small pediatric donors (VSPDs, aged <2 y) are underutilized. Concerns regarding potentially inferior outcomes hinder the use in pediatric recipients.

METHODS

All pediatric kidney-only transplants from <18-year-old donors between January 2012 and May 2021 in our center were included in this study. Outcomes were compared between VSPD and normal pediatric donor (NPD, aged 2-18 y) groups, and 3-y death-censored graft survival was assessed by the multivariable Cox proportional hazard model.

RESULTS

Of all 252 enrolled patients, 149 (59.1%) received kidneys from NPDs and 103 (40.9%) from VSPDs. The 3-y graft survival rates of the NPD and VSPD groups were 91.2% and 88.6%, respectively ( P = 0.385). The adjusted hazard ratio of 3-y graft loss was 1.2 (95% confidence interval, 0.6-2.5; P = 0.659) for the VSPD group compared with the NPD group. There was no significant difference in estimated glomerular filtration rate at 3 y posttransplant observed between NPD and VSPD groups (86.9 ± 26.8 versus 87 ± 27.9 mL/min/1.73 m 2 ; P = 0.991). Patients (n = 12, 4.8%) who received kidneys from donors <5 kg contributed 5 (5/39, 12.8%) with delayed graft function and the sole primary nonfunction in our cohort.

CONCLUSIONS

Although attention to preventing complications is necessary, especially for kidneys from donors <5 kg, kidneys from VSPDs did not appear to impart added risk for 3-y graft loss and renal function.

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.

Epidemiology of pediatric chronic kidney disease/kidney failure: learning from registries and cohort studies

Although the concept of chronic kidney disease (CKD) in children is similar to that in adults, pediatric CKD has some peculiarities, and there is less evidence and many factors that are not clearly understood. The past decade has witnessed several additional registry and cohort studies of pediatric CKD and kidney failure. The most common underlying disease in pediatric CKD and kidney failure is congenital anomalies of the kidney and urinary tract (CAKUT), which is one of the major characteristics of CKD in children. The incidence/prevalence of CKD in children varies worldwide. Hypertension and proteinuria are independent risk factors for CKD progression; other factors that may affect CKD progression are primary disease, age, sex, racial/genetic factors, urological problems, low birth weight, and social background. Many studies based on registry data revealed that the risk factors for mortality among children with kidney failure who are receiving kidney replacement therapy are younger age, female sex, non-White race, non-CAKUT etiologies, anemia, hypoalbuminemia, and high estimated glomerular filtration rate at dialysis initiation. The evidence has contributed to clinical practice. The results of these registry-based studies are expected to lead to new improvements in pediatric CKD care.

Update on C1 Esterase Inhibitor in Human Solid Organ Transplantation

Complement plays important roles in both ischemia-reperfusion injury (IRI) and antibody-mediated rejection (AMR) of solid organ allografts. One approach to possibly improve outcomes after transplantation is the use of C1 inhibitor (C1-INH), which blocks the first step in both the classical and lectin pathways of complement activation and also inhibits the contact, coagulation, and kinin systems. C1-INH can also directly block leukocyte-endothelial cell adhesion. C1-INH contrasts with eculizumab and other distal inhibitors, which do not affect C4b or C3b deposition or noncomplement pathways. Authors of reports on trials in kidney transplant recipients have suggested that C1-INH treatment may reduce IRI and delayed graft function, based on decreased requirements for dialysis in the first month after transplantation. This effect was particularly marked with grafts with Kidney Disease Profile Index ≥ 85. Other clinical studies and models suggest that C1-INH may decrease sensitization and donor-specific antibody production and might improve outcomes in AMR, including in patients who are refractory to other modalities. However, the studies have been small and often only single-center. This article reviews clinical data and ongoing trials with C1-INH in transplant recipients, compares the results with those of other complement inhibitors, and summarizes potentially productive directions for future research.

Is there a functional disadvantage to using the external iliac vessels for vascular anastomosis in children and adolescents undergoing renal transplantation?

PURPOSE

RT remains the best available strategy for addressing stage 5 chronic kidney disease in children and adolescents. Technical aspects of the procedure can have a clear impact on complications and health of the allograft, including DGF. Immediate optimal perfusion is paramount, thus choosing a target vessel has to take into account the flow demands imposed by an adult-size kidney in a proportionally smaller recipient. Herein, we explore the hypothesis that vascular anastomosis location can impact DGF adjusting for patient age and body size.

METHODS

Retrospective review of a single institution referral center transplant database, including information on 156 patients. We collected data on patient characteristics (age, height, BSA, gender, preoperative need for dialysis), donor source (deceased vs living), WIT/CIT, hemodynamics during the procedure, use of inotropes or diuretics, and location of the arterial and venous anastomoses. The primary outcome, DGF, was assessed by measuring the ttNC (in days), adjusting for age and BSA.

RESULTS

Location of the arterial anastomosis was clearly impacted by age and donor size (Figure 1A). On univariate analyses, longer ttNC was associated with deceased vs living donor (11.8 ± 11.5 and 4.3 ± 5.0; P < 0.001), preoperative need for dialysis (9.7 ± 11.0 and 6.5 ± 6.0, P = 0.02), location of arterial anastomosis (aorta [n = 21] 4.9 ± 6.1, common iliac [n = 93] 7.1 ± 7.3, external iliac 14.7 ± 14.5; P < 0.001, Figure 1B) and venous anastomosis (vena cava [n = 21] 5.6 ± 6.3, common iliac [n = 89] 7.1 ± 7.6, external iliac [n = 44] 13.8 ± 14); P < 0.001). On multivariable analysis, this association remained statistically significant when adjusting for recipient age, height, BSA, donor source, change in blood pressure with unclamping, and use of inotropes and preoperative dialysis. The detrimental effect on ttNC was more salient when comparing external iliac vs common iliac and aorta or vena cava.

CONCLUSION

Our data suggest that anastomosis to a smaller caliber target vessel (ie, external iliac) in comparison with the common iliac or aorta/vena cava may be a risk factor for delayed return of graft function, independent of recipient size and donor source. This finding merit further evaluation, as it may help with intraoperative decision making during pediatric and adolescent RT.

Proteins in Preservation Fluid as Predictors of Delayed Graft Function in Kidneys from Donors after Circulatory Death

BACKGROUND AND OBJECTIVES

Kidney transplantation is the preferred treatment for ESRD, and donor kidney shortage urges proper donor-recipient matching. Zero-hour biopsies provide predictive values for short- and long-term transplantation outcomes, but are invasive and may not reflect the entire organ. Alternative, more representative methods to predict transplantation outcome are required. We hypothesized that proteins accumulating in preservation fluid during cold ischemic storage can serve as biomarkers to predict post-transplantation graft function.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Levels of 158 proteins were measured in preservation fluids from kidneys donated after circulatory death (Maastricht category III) collected in two Dutch centers (University Medical Center Utrecht and Erasmus Medical Center Rotterdam) between 2013 and 2015. Five candidate biomarkers identified in a discovery set of eight kidneys with immediate function (IF) versus eight with delayed graft function (DGF) were subsequently analyzed in a verification set of 40 additional preservation fluids to establish a prediction model.

RESULTS

Variables tested for their contribution to a prediction model included five proteins (leptin, periostin, GM-CSF, plasminogen activator inhibitor-1, and osteopontin) and two clinical parameters (recipient body mass index [BMI] and dialysis duration) that distinguished between IF and DGF in the discovery set. Stepwise multivariable logistic regression provided a prediction model on the basis of leptin and GM-CSF. Receiver operating characteristic analysis showed an area under the curve (AUC) of 0.87, and addition of recipient BMI generated a model with an AUC of 0.89, outperforming the Kidney Donor Risk Index and the DGF risk calculator, showing AUCs of 0.55 and 0.59, respectively.

CONCLUSIONS

We demonstrate that donor kidney preservation fluid harbors biomarkers that, together with information on recipient BMI, predict short-term post-transplantation kidney function. Our approach is safe, easy, and performs better than current prediction algorithms, which are only on the basis of clinical parameters.