Does Rabbit Antithymocyte Globulin (Thymoglobuline®) Have a Role in Avoiding Delayed Graft Function in the Modern Era of Kidney Transplantation?

Understanding Delayed Graft Function to Improve Organ Utilization and Patient Outcomes: Report of a Scientific Workshop Sponsored by the National Kidney Foundation

Delayed graft function (DGF) is a common complication after kidney transplant. Despite extensive literature on the topic, the extant definition of DGF has not been conducive to advancing the scientific understanding of the influences and mechanisms contributing to its onset, duration, resolution, or long-term prognostic implications. In 2022, the National Kidney Foundation sponsored a multidisciplinary scientific workshop to comprehensively review the current state of knowledge about the diagnosis, therapy, and management of DGF and conducted a survey of relevant stakeholders on topics of clinical and regulatory interest. In this Special Report, we propose and defend a novel taxonomy for the clinical and research definitions of DGF, address key regulatory and clinical practice issues surrounding DGF, review the current state of therapies to reduce and/or attenuate DGF, offer considerations for clinical practice related to the outpatient management of DGF, and outline a prospective research and policy agenda.

The effect of late-onset CMV infection on the outcome of renal allograft considering initial graft function

BACKGROUND

Delayed graft function (DGF) increases the renal allograft failure risk. Late-onset Cytomegalovirus (CMV) infection's effect on the association between DGF and allograft failure has not been determined.

METHODS

In this retrospective cohort, we included all renal allograft recipients at London Health Sciences Centre from January 1, 2014 to December 30, 2017, and continued clinical follow-up until February 28, 2020. We determined whether late-onset CMV infection affects the association between DGF and allograft failure in stratified and Cox proportional hazard analyses.

RESULTS

Of 384 patients (median age [interquartile range]: 55 [43.3-63]; 38.7% female), 57 recipients (14.8%) were diagnosed with DGF. Patients with DGF were at a greater risk of CMV infection than patients without DGF (22.8% vs. 11.3%, p = .017). Late-onset CMV infection (odds ratio [OR]: 4.7, 95% CI: 2.07-10.68) and rejection (OR: 9.59, 95% CI: 4.15-22.16) significantly increased the risk of allograft failure in recipients with DGF. Patients with DGF had a significantly greater risk of graft failure than those without DGF (17.5% vs. 6.1%, p = .007). In the adjusted Cox hazard model, CMV infection significantly increased the risk of allograft failure (aHR: 3.19, 95% CI: 1.49-6.84).

CONCLUSION

Late-onset CMV infection considerably increased the risk of graft failure in patients with DGF. A hybrid preventive model including prophylaxis followed by CMV-specific cell-mediated immunity monitoring may decrease the risk of allograft failure in recipients with DGF.

Baseline Characteristics and Representativeness of Participants in the BEST-Fluids Trial: A Randomized Trial of Balanced Crystalloid Solution Versus Saline in Deceased Donor Kidney Transplantation

Delayed graft function (DGF) is a major complication of deceased donor kidney transplantation. Saline (0.9% sodium chloride) is a commonly used intravenous fluid in transplantation but may increase the risk of DGF because of its high chloride content. Better Evidence for Selecting Transplant Fluids (BEST-Fluids), a pragmatic, registry-based, double-blind, randomized trial, sought to determine whether using a balanced low-chloride crystalloid solution (Plasma-Lyte 148) instead of saline would reduce DGF. We sought to evaluate the generalizability of the trial cohort by reporting the baseline characteristics and representativeness of the trial participants in detail.

METHODS

We compared the characteristics of BEST-Fluids participants with those of a contemporary cohort of deceased donor kidney transplant recipients in Australia and New Zealand using data from the Australia and New Zealand Dialysis and Transplant Registry. To explore potential international differences, we compared trial participants with a cohort of transplant recipients in the United States using data from the Scientific Registry of Transplant Recipients.

RESULTS

During the trial recruitment period, 2373 deceased donor kidney transplants were performed in Australia and New Zealand; 2178 were eligible' and 808 were enrolled in BEST-Fluids. Overall, trial participants and nonparticipants were similar at baseline. Trial participants had more coronary artery disease (standardized difference [d] = 0.09; P = 0.03), longer dialysis duration (d = 0.18, P < 0.001), and fewer hypertensive (d = -0.11, P = 0.03) and circulatory death (d = -0.14, P < 0.01) donors than nonparticipants. Most key characteristics were similar between trial participants and US recipients, with moderate differences (|d| ≥ 0.2; all P < 0.001) in kidney failure cause, diabetes, dialysis duration, ischemic time, and several donor risk predictors, likely reflecting underlying population differences.

CONCLUSIONS

BEST-Fluids participants had more comorbidities and received slightly fewer high-risk deceased donor kidneys but were otherwise representative of Australian and New Zealand transplant recipients and were generally similar to US recipients. The trial results should be broadly applicable to deceased donor kidney transplantation practice worldwide.

The influence of the antithymocyte globulin dose on clinical outcomes of patients undergoing kidney retransplantation

Optimizing antithymocyte globulin (rATG) dosage is critical for high immunological risk patients undergoing a repeat kidney transplant. This natural retrospective cohort study compared clinical outcomes of two successive cohorts of consecutive recipients of retransplants receiving 5 x 1 mg/kg (rATG-5, n = 100) or a single 3 mg/kg (rATG-3, n = 110) dose of rATG induction therapy. All patients had negative complement-dependent cytotoxicity crossmatch and no anti-HLA A, B, DR donor-specific antibodies (DSA). The primary endpoint was efficacy failure (first biopsy-proven acute rejection, graft loss, or death) at 12 months. There was no difference in the cumulative incidence of efficacy failure (18.0% vs. 21.8%, HR = 1.22, 95% CI 0.66–2.25), respectively. There were no differences in 3-years freedom from biopsy proven acute rejection, and patient, graft, and death-censored graft survivals. There were no differences in the incidence of surgical complications (25.0% vs. 18.2%; p 0.151), early hospital readmission (27.8% vs. 29.5%; p = 0.877) and CMV infections (49% vs. 40%; p = 0.190). There were also no differences in the incidence (59.6% vs. 58.7%, p = 0.897) and duration of delayed graft function but a stable difference in estimate glomerular filtration rate was observed from month 1 (54.7±28.8 vs. 44.1±25.3 ml/min/1.73 m², p = 0.005) to month 36 (51.1±27.7 vs. 42.5±24.5, p = 0.019). Mean urinary protein concentration (month 36: 0.38±0.81 vs. 0.70±2.40 g/ml, p = 0.008) and mean chronic glomerular Banff score in for cause biopsies (months 4–36: 0.0±0.0 vs. 0.04±0.26, p = 0.044) were higher in the rATG-3 group. This cohort analysis did not detect differences in the incidence of efficacy failure and in safety outcomes at 12 months among recipients of kidney retransplants without A, B, and DR DSA, receiving induction therapy with a single 3 mg/kg rATG dose or the traditional 5 mg/kg rATG.

Ideal Body Weight-Based Dosing of Rabbit Antithymocyte Globulin for Cost Minimization in Kidney Transplantation

INTRODUCTION

Contemporary dosing strategies for rabbit anti-thymocyte globulin (rATG) in kidney transplantation aim to reduce cumulative exposure, minimizing long-term adverse events. The use of ideal body weight-based dosing has been trialed, however concern for increased rejection post-transplant exists due to lower doses of rATG. Research Questions: The primary aim of this study was to compare rejection rates between rATG dosing protocols using actual body weight and ideal body weight and secondarily to evaluate cost savings following protocol implementation.

DESIGN

This was a retrospective study surrounding implementation of an ideal body weight-based dosing protocol for rATG. We compared 75 kidney transplant recipients in whom rATG was dosed based on actual body weight (pre-protocol group) to 64 in whom dosing was based on ideal body weight (post-protocol group), following a nine-month washout.

RESULTS

The mean cumulative rATG dose in the pre-protocol group was 6.3 mg/kg of actual body weight. When ideal body weight was used in the post-protocol group, the mean dose was 4.5 mg/kg of actual body weight. The rejection rate was 18.7% pre-protocol and 23.4% postprotocol, which did not represent a statistically significant difference (p = 0.491). The actual annual cost savings after protocol implementation exceeded $162,000, approximately $2,500 per patient.

CONCLUSION

Results suggest ideal body weight-based dosing of rATG may reduce exposure and cost, without significantly impacting the risk of rejection in kidney transplant recipients. More studies are needed to confirm these findings.

Safety and effectiveness of kidney transplantation using a donation after brain death donor with acute kidney injury: a retrospective cohort study

The use of kidneys from donation after brain death (DBD) donors with acute kidney injury (AKI) is a strategy to expand the donor pool. The aim of this study was to evaluate how kidney transplantation (KT) from a donor with AKI affects long-term graft survival in various situations. All patients who underwent KT from DBD donors between June 2003 and April 2016 were retrospectively reviewed. The KDIGO (Kidney Disease: Improving Global Outcomes) criteria were used to classify donor AKI. The cohort included 376 donors (no AKI group, n = 117 [31.1%]; AKI group n = 259 [68.9%]). Death-censored graft survival was similar according to the presence of AKI, AKI severity, and the AKI trend (p = 0.929, p = 0.077, and p = 0.658, respectively). Patients whose donors had AKI who received using low dose (1.5 mg/kg for three days) rabbit anti-thymocyte globulin (r-ATG) as the induction agent had significantly superior death-censored graft survival compared with patients in that group who received basiliximab (p = 0.039). AKI in DBD donors did not affect long-term death-censored graft survival. Low-dose r-ATG may be considered as an induction immunosuppression in recipients receiving kidneys with AKI because it showed better graft survival than basiliximab.

Canadian survey on the rates of use of intraoperative diuretics and justification for their use during renal allograft reperfusion

BACKGROUND

Mannitol and furosemide have been used as diuretics intraoperatively to facilitate early renal allograft function and reduce delayed graft function. As the evidence of any efficacy of these agents is limited, we sought to characterize the use of diuretics among transplant surgeons.

METHODS

An anonymous online survey was sent to all Canadian transplant programs where kidney transplants are routinely performed. Questions were related to the use and indications for mannitol and furosemide. Responses were collected and analyzed as counts and percentages of respondents. We used χ2 analysis to assess the relationship between demographic factors and survey responses.

RESULTS

Thirty-five surgeons completed the survey (response rate 50%). Seventy per cent of respondents reported performing 26 or more transplants per year, 88% had formal transplant fellowship training and 67% indicated that they currently train fellows. Only 24% and 12% reported believing that delayed graft function is reduced by mannitol and furosemide use, respectively. However, 73% routinely gave mannitol to patients and 53% routinely gave furosemide. The most common justification given for mannitol use was to induce diuresis (54%); 37% of respondents reported using mannitol because of training dogma. Likewise, 57% used furosemide for diuresis, with 23% reporting that their use of this agent was based on dogma. No relationship emerged between fellowship training, case volume or training program status and the use of any agent. Interestingly, 71% of respondents indicated that a randomized controlled trial evaluating the utility of intraoperative diuretics is needed and that they were interested in participating in such a trial.

CONCLUSION

Use of intraoperative diuretics and the rationale for their use vary among surgeons. A substantial proportion of surgeons use these medications on the basis of dogma alone. A randomized controlled trial is needed to clarify the role of intraoperative diuretics in kidney transplant surgery.

Donor Age, Cold Ischemia Time, and Delayed Graft Function

BACKGROUND AND OBJECTIVES

Increased donor age is one of the most important risk factors for delayed graft function (DGF), and previous studies suggest that the harmful effect of cold ischemia time is increased in kidneys from older donors. Our aim was to study the association of increased donor age and cold ischemia time with the risk of delayed graft function in a large cohort kidney transplants from the current era.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Scientific Registry of Transplant Recipients was used for this observational, retrospective registry analysis to identify all deceased donor kidney transplantations in the United States between 2010 and September 2018, who were on dialysis pretransplantation (n=90,810). The association of donor age and cold ischemia time with the risk of DGF was analyzed in multivariable models adjusted for recipient characteristics (age, race, sex, diabetes, calculated panel-reactive antibodies, pretransplant dialysis duration) and donor characteristics (cause of death, sex, race, body mass index, creatinine, donation after circulatory death status, history of hypertension, and HLA mismatch).

RESULTS

Cold ischemia time and donor age were independently associated with the risk of DGF, but the risk of DGF was not statistically significantly lower in donor age categories between 50 and 64 years, compared with donors ≥65 years. The harmful association of cold ischemia time was not higher in kidneys from older donors in any age category, not even among donation after circulatory death donors. When donor risk was assessed with kidney donor profile index, although a statistically significant interaction with cold ischemia time was found, no practically meaningful increase in cold-ischemia susceptibility of kidneys with a high kidney donor profile index was found.

CONCLUSIONS

We were unable to demonstrate an association between donor age and DGF. The association of longer cold ischemia time with the risk of DGF was not magnified in older or more marginal donors.