Cold ischemic time is critical in outcomes of expanded criteria donor renal transplantation

Kidney utility and futility

Changes in kidney allocation coupled with the COVID-19 pandemic have placed tremendous strain on current systems of organ distribution and logistics. Although the number of deceased donors continues to rise annually in the United States, the proportion of marginal deceased donors (MDDs) is disproportionately growing. Cold ischemia times and kidney discard rates are rising in part related to inadequate planning, resources, and shortages. Complexity in kidney allocation and distribution has contributed to this dilemma. Logistical issues and the ability to reperfuse the kidney within acceptable time constraints increasingly determine clinical decision-making for organ acceptance. We have a good understanding of the phenotype of "hard to place" MDD kidneys, yet continue to promote a "one size fits all" approach to organ allocation. Allocation and transportation systems need to be agile, mobile, and flexible in order to accommodate the expanding numbers of MDD organs. By identifying "hard to place" MDD kidneys early and implementing a "fast-track" or open offer policy to expedite placement, the utilization rate of MDDs would improve dramatically. Organ allocation and distribution based on location, motivation, and innovation must lead the way. In the absence of change, we are sacrificing utility for futility and discard rates will continue to escalate.

Dual kidney transplants from adult marginal donors: Review and perspective

The practice of dual kidney transplantation (DKT) from adult marginal deceased donors (MDDs) dates back to the mid-1990s with initial pioneering experiences reported by the Stanford and Maryland groups, at which time the primary indication was estimated insufficient nephron mass from older donors. Multiple subsequent studies of short and long-term success have been reported focusing on three major aspects of DKT: Identifying appropriate selection criteria and developing scoring systems based on pre- and post-donation factors; refining technical aspects; and analyzing mid-term outcomes. The number of adult DKTs performed in the United States has declined in the past decade and only about 60 are performed annually. For adult deceased donor kidneys meeting double allocation criteria, >60% are ultimately not transplanted. Deceased donors with limited renal functional capacity represent a large proportion of potential kidneys doomed to either discard or non-recovery. However, DKT may reduce organ discard and optimize the use of kidneys from MDDs. In an attempt to promote utilization of MDD kidneys, the United Network for Organ Sharing introduced new allocation guidelines pursuant to DKT in 2019. The purpose of this review is to chronicle the history of DKT and identify opportunities to improve utilization of MDD kidneys through DKT. This article is protected by copyright. All rights reserved.

Comparative Analysis of Risk Factors in Declined Kidneys from Donation after Brain Death and Circulatory Death

Background and objectives: Kidneys from donation after circulatory death (DCD) are more likely to be declined for transplantation compared with kidneys from donation after brain death (DBD). The aim of this study was to evaluate characteristics in the biopsies of human DCD and DBD kidneys that were declined for transplantation in order to rescue more DCD kidneys. Materials and Methods: Sixty kidney donors (DCD = 36, DBD = 24) were recruited into the study and assessed using donor demographics. Kidney biopsies taken post cold storage were also evaluated for histological damage, inflammation (myeloperoxidase, MPO), von Willebrand factor (vWF) expression, complement 4d (C4d) deposition and complement 3 (C3) activation using H&E and immunohistochemistry staining, and Western blotting. Results: More DBD donors (16/24) had a history of hypertension compared with DCDs (8/36, p = 0.001). The mean warm ischemic time in the DCD kidneys was 12.9 ± 3.9 min. The mean cold ischemic time was not significantly different between the two groups of kidney donors (DBD 33.3 ± 16.7 vs. DCD 28.6 ± 14.1 h, p > 0.05). The score of histological damage and MPO, as well as the reactivity of vWF, C4d and C3, varied between kidneys, but there was no significant difference between the two donor types (p > 0.05). However, vWF reactivity might be an early indicator for loss of tissue integrity, while C4d deposition and activated C3 might be better predictors for histological damage. Conclusions: Similar characteristics of DCD were shown in comparison with DBD kidneys. Importantly, the additional warm ischemic time in DCD appeared to have no further detectable adverse effects on tissue injury, inflammation and complement activation. vWF, C4d and C3 might be potential biomarkers facilitating the evaluation of donor kidneys.

Validation of the Kidney Donor Profile Index in Argentina

Kidney Donor Profile Index (KDPI), derived from donor characteristics, was developed in the United States in an effort to devise an objective means of assessing donor organ suitability based on predicted graft survival. The objective of this study is to analyze the utility of KDPI to predict renal graft survival in Argentina. We conducted a retrospective national cohort study of adult patients who received a deceased donor renal transplantation in Argentina between January 2008 and December 2017. The graft survival was estimated according to the KDPI stratified by quartiles. A Kaplan-Meier analysis was used to calculate survival. A Cox regression was performed to estimate the probability of graft loss for each quart of the KDPI adjusted by receptor variables (age, diabetes, sex, and dialysis time) and cold ischemia time. In a Kaplan-Meier analysis, the graft survival decreases as the quartile of KDPI increases. Multivariate analysis shows that the increase in KDPI quartile and recipient's characteristics-such as age ≥60 years, diabetes, and dialysis time-were related to the probability of graft loss. In conclusion, the KDPI system could provide a guide to objectively assess the quality of organs offered for transplantation in Argentina.

Expanded Criteria Donor Kidneys With Kidney Donor Profile Index ≤ 85%: Are We Doing Enough to Counsel Our Patients?

BACKGROUND

Kidneys at higher risk for allograft failure are defined by the Kidney Donor Profile Index (KDPI) > 85% in the current kidney allocation system (KAS), replacing the historical concept of expanded criteria donor (ECD) kidneys in the previous KAS. Discrepancies exist in the classification of "high-risk kidneys" between the 2 KAS. In the current KAS, only recipients of KDPI > 85% kidneys are counseled about the high risk of allograft failure and are required to sign a consent. In this study, we evaluated the outcomes and allocation of kidneys with discordant classification.

METHODS

Using the Scientific Registry of Transplant Recipients, kidneys transplanted between 01/2002 and 09/2016 were classified according to the old (standard criteria donor [SCD]/ECD) and current (KDPI) KAS. We then grouped them as concordant (KDPI ≤ 85% + SCD or KDPI > 85% + ECD) and discordant (KDPI ≤ 85% + ECD or KDPI > 85% + SCD) kidneys.

RESULTS

Approximately 11% of transplanted kidneys were discordant in classification. Among kidneys with KDPI ≤ 85%, ECD status conferred a 64% (95% CI: 56%-73%) higher risk of allograft failure compared to SCD status. However, SCD/ECD status was not associated with differential outcomes in KDPI > 85% kidneys. These ECD kidneys have KDPIs > 50% and have been transplanted across all estimated post-transplant survival (EPTS) deciles.

CONCLUSION

Adequate counseling about the risk and benefit of accepting ECD kidneys with KDPI ≤ 85% versus waiting on dialysis should be explored with the patients, especially those with lower EPTS.

Comparison of nighttime and daytime operation on outcomes of kidney transplant with deceased donors: a retrospective analysis

Background:

Kidney transplant is always emergent operations and frequently need to be performed at nighttime to reduce cold ischemia time (CIT). Previous studies have revealed that fatigue and sleep deprivation can result in adverse consequences of medical procedures. This study aimed to evaluate whether nighttime operation has adverse impact on kidney transplant.

Methods:

A retrospective analysis of recipients accepted kidney transplant from deceased donors in one center from 2014 to 2016 was performed. Daytime transplant was defined as operation started after 8 am or ended before 8 pm and nighttime operation was defined as operation ended after 8 pm or started before 8 am. The incidences of complications such as delayed graft function, acute rejection, surgical complications and nosocomial infections were compared between 2 groups. Student's t-test was used to analyze continuous variables such as serum creatinine (Scr) at 1-year of post-transplant. The Chi-square test was used to analyze categorical variables. Differences in recipients and graft survival were analyzed using Kaplan–Meier methodology and log-rank tests.

Results:

Among the 443 recipients, 233 (52.6%) were classified into the daytime group and the others 210 (47.4%) were in the nighttime group. The 1-year survival rate of recipients was similar for the recipients in the daytime and nighttime groups (95.3% vs. 95.2%, P = 0.981). Although the 1-year graft survival rate in the nighttime group was slightly superior to that in the daytime group, the difference was not significant (92.4% vs. 88.4%, P = 0.164). Furthermore, Scr and incidence of complications were also not significantly different between the 2 groups.

Conclusions:

Our results suggested that operation time of kidney transplant with short CIT has no significant impact on the outcome of kidney transplant. Nighttime operation of kidney transplant with short CIT could be postponed to the following day to alleviate the burden on medical staffs and avoid the potential risk.

N,N-dimethyltryptamine Prevents Renal Ischemia-Reperfusion Injury in a Rat Model

BACKGROUND

Ischemia reperfusion (I/R) injury remains one of the most challenging fields of organ transplantation. It is highly associated with the use of expanded criteria donors that might conclude to delayed graft function or early or late graft failure.

OBJECTIVE

To investigate the metabolic, microcirculatory parameters, and histologic changes under the effect of N,N-dimethyltryptamine (DMT) in a renal I/R model in rats.

METHOD

In 26 anesthetized rats both kidneys were exposed. In the control group (n = 6) no other intervention happened. In 20 other animals, the right renal vessels were ligated, and after 60 minutes the right kidney was removed. The left renal vessels were clamped for 60 minutes then released, followed by 120 minutes of reperfusion. In the I/R group (n = 10), there was no additive treatment, while in I/R + DMT group (n = 10) DMT was administered 15 minutes before ischemia. Blood samples were taken, laser Doppler measurement was performed, and both kidneys were evaluated histologically.

RESULTS

Microcirculation (blood flux units [BFU]) diminished in all groups, but remarkably so in the I/R + DMT group. This group compensated better after the 30th minute of reperfusion. The control and I/R + DMT groups had similar BFUs after 120 minutes of reperfusion, but in the I/R group BFU was higher. Tubular necrosis developed in the I/R and I/R + DMT groups too; it was moderated under DMT effect, and severe without. Histologic injuries were less in I/R + DMT Group compared to non-treated animals.

CONCLUSION

Histologic changes characteristic to I/R injuries were reversible and microcirculation recovered at the end of 120 minutes reperfusion under the administration of DMT. DMT can be used for renoprotection in kidney transplantation.

Relationship Between Individual Components of the Extended-Criteria Donor Definition and the First Post-transplant Kidney Graft Resistance Index, Measured by Doppler Sonography

BACKGROUND

Despite an increasing utilization of kidneys procured from expanded-criteria donors, little is known about the effects of particular expanded-criteria donors definition components, that is, hypertension, increased creatinine prior to procurement, and cerebrovascular cause of death on the kidney graft Doppler parameters measured shortly after transplantation, whose increased values are associated with unfavorable outcomes. Hence, we analyzed the relationship between expanded-criteria donors components and resistance index values measured within 2 to 3 days post-transplant.

MATERIAL AND METHODS

The initial post-transplant resistance index value was measured in 676 consecutive successful first cadaveric kidney graft recipients without delayed graft function or early acute rejection episode. We analyzed resistance index values in 460 patients transplanted with organs from donors <50 years and in 216 recipients with organs from donors >50 years old.

RESULTS

In general, expanded-criteria donors status did not influence the initial resistance index values in the whole study group. Unexpectedly, in older donor groups, both the occurrence of donor hypertension and cerebrovascular cause of death resulted in significantly lower resistance index values in kidney graft recipients (0.73 ± 0.10 vs 0.76 ± 0.11 in the non-hypertension group, P = .013 and 0.74 ± 0.11 vs 0.78 ± 0.10 in the non-cerebrovascular cause of death group, P = .015, respectively). In the Cox proportional regression model for graft survival, cerebrovascular cause of death was increasing the risk of graft loss by 55%, while recipient's age had the opposite effect, decreasing the risk of graft loss by 2% per year.

CONCLUSIONS

Regardless of the limited influence of expanded-criteria donor status on first post-transplant resistance index value, the long-term observation shows moderate but significantly worse kidney graft survival, mostly as a result of the cerebrovascular cause of donor's death.

Tissue conservation for transplantation

Pathophysiological changes that occur during ischemia and subsequent reperfusion cause damage to tissues procured for transplantation and also affect long-term allograft function and survival. The proper preservation of organs before transplantation is a must to limit these injuries as much as possible. For decades, static cold storage has been the gold standard for organ preservation, with mechanical perfusion developing as a promising alternative only recently. The current literature points to the need of developing dedicated preservation protocols for every organ, which in combination with other interventions such as ischemic preconditioning and therapeutic additives offer the possibility of improving organ preservation and extending it to multiple times its current duration. This review strives to present an overview of the current body of knowledge with regard to the preservation of organs and tissues destined for transplantation.

Analysis of local versus imported expanded criteria donor kidneys: A single-center experience with 497 ECD kidney transplants

BACKGROUND

The value of importing expanded criteria donor (ECD) kidneys is uncertain.

METHODS

We retrospectively reviewed our single-center experience with ECD kidney transplants (KT).

RESULTS

Over 12.8 years, we performed 497 ECD KTs including 247 local and 250 imported from other donor service areas. The import ECD group had more donors (16% vs 9%) ≥ age 70, more zero human leukocyte antigen mismatches (14% vs 2%), more KTs with a cold ischemia time >30 hours (46% vs 19%), and fewer kidneys managed with pump preservation (78% vs 92%, all P≤.05) compared to the local ECD group. Mean Kidney Donor Profile Index were 80% import vs 84% local. With a mean follow-up of 55 months, actual patient and graft survival rates were 71% and 58% in import vs 76% and 58% in local ECD KTs, respectively. Death-censored graft survival rates were 70% in import vs 69% in local ECD KTs. Delayed graft function occurred in 28% import vs 23% local ECD KTs (P=NS) whereas the incidence of primary nonfunction was slightly higher with import ECD kidneys (4.8% vs 2.4%, P=.23).

CONCLUSIONS

Midterm outcomes are remarkably similar for import vs local ECD KTs, suggesting that broader sharing of ECD kidneys may improve utilization without compromising outcomes.

Advances in the Knowledge about Kidney Decellularization and Repopulation

End-stage renal disease (ESRD) is characterized by the progressive deterioration of renal function that may compromise different tissues and organs. The major treatment indicated for patients with ESRD is kidney transplantation. However, the shortage of available organs, as well as the high rate of organ rejection, supports the need for new therapies. Thus, the implementation of tissue bioengineering to organ regeneration has emerged as an alternative to traditional organ transplantation. Decellularization of organs with chemical, physical, and/or biological agents generates natural scaffolds, which can serve as basis for tissue reconstruction. The recellularization of these scaffolds with different cell sources, such as stem cells or adult differentiated cells, can provide an organ with functionality and no immune response after in vivo transplantation on the host. Several studies have focused on improving these techniques, but until now, there is no optimal decellularization method for the kidney available yet. Herein, an overview of the current literature for kidney decellularization and whole-organ recellularization is presented, addressing the pros and cons of the actual techniques already developed, the methods adopted to evaluate the efficacy of the procedures, and the challenges to be overcome in order to achieve an optimal protocol.

[Deceased donation in renal transplantation]

OBJECTIVES

To review epidemiologic data's and medical results of deceased donation in renal transplantation.

MATERIAL AND METHODS

Relevant publications were identified through Medline (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) database using the following keywords, alone or in association, "brain death; cardiac arrest; deceased donation; organ procurement; transplantation". Articles were selected according to methods, language of publication and relevance. The reference lists were used to identify additional historical studies of interest. Both prospective and retrospective series, in French and English, as well as review articles and recommendations were selected. In addition, French national transplant and health agencies (http://www.agence-biomedecine.fr and http://www.has-sante.fr) databases were screened using identical keywords. A total of 2498 articles, 8 official reports and 17 newspaper articles were identified; after careful selection 157 publications were eligible for our review.

RESULTS

Deceased donation may involve either brain death or non-heartbeating donors (NHBD). Organ shortage led to the procurement of organs from expanded-criteria donors, with an increased age at donation and extended vascular disease, leading to inferior results after transplantation and underlining the need for careful donor management during brain death or cardiac arrest. Evolution of French legislation covering bioethics allowed procurement from Maastricht categories II and recently III non-heartbeating donors.

CONCLUSION

The increase of organ shortage emphasizes the need for a rigorous surgical technique during procurement to avoid loss of transplants. A history or current neoplasm in deceased-donors, requires attention to increase the pool of organs without putting the recipients at risk for cancer transmission. French NHBD program, especially from Maastricht category III, may stand for a potential source of valuable organs.

Dual kidney transplants from adult marginal donors successfully expand the limited deceased donor organ pool

BACKGROUND

The need to expand the organ donor pool remains a formidable challenge in kidney transplantation (KT). The use of expanded criteria donors (ECDs) represents one approach, but kidney discard rates are high because of concerns regarding overall quality. Dual KT (DKT) may reduce organ discard and optimize the use of kidneys from marginal donors.

STUDY DESIGN

We conducted a single-center retrospective review of outcomes in adult recipients of DKTs from adult marginal deceased donors (DD) defined by limited renal functional capacity. If the calculated creatinine clearance in an adult DD was <65 mL/min, then the kidneys were transplanted as a DKT.

RESULTS

Over 11.5 yr, 72 DKTS were performed including 45 from ECDs, 17 from donation after cardiac death (DCD) donors, and 10 from standard criteria donors (SCD). Mean adult DD and recipient ages were both 60 yr, including 29 DDs and 26 recipients ≥65 yr of age. Mean pre-DKT waiting and dialysis vintage times were 12 months and 25 months, respectively. Actual patient and graft survival rates were 84.7% and 70.8%, respectively, with a mean follow-up of 58 months. One yr and death-censored graft survival rates were 90% and 80%, respectively. Outcomes did not differ by DD category, recipient age, or presence of delayed graft function (DGF). Eleven patients died at a mean of 32 months post-DKT (eight with functioning grafts) and 13 other patients experienced graft losses at a mean of 33 months. The incidence of DGF was 25%; there were two cases (2.8%) of primary non-function. Mean length of initial hospital stay was 7.2 d. Mean serum creatinine and glomerular filtration rate levels at 12 and 24 months were 1.5 and 53 and 1.5 mg/dL and 51 mL/min/1.73 m(2) , respectively. DKT graft survival and function were superior to concurrent single ECD and similar to concurrent SCD KTs. Two patients underwent successful kidney retransplantation, so the dialysis-free rate in surviving patients was 87%. The proportion of total renal function transplanted from adult DD to DKT recipients was 77% compared to 56% for patients receiving single KTs.

CONCLUSIONS

Dual kidney transplantation using kidneys from adult marginal DDs that otherwise might be discarded offer a viable option to counteract the growing shortage of acceptable single kidneys. Excellent medium-term outcomes can be achieved and waiting times can be reduced in a predominantly older recipient population.

Comparison of survival outcomes between Expanded Criteria Donor and Standard Criteria Donor kidney transplant recipients: a systematic review and meta-analysis

In 2002, the United Network for Organ Sharing proposed increasing the pool of donor kidneys to include Expanded Criteria Donor (ECD). Outside the USA, the ECD definition remains the one used without questioning whether such a graft allocation criterion is valid worldwide. We performed a meta-analysis to quantify the differences between ECD and Standard Criteria Donor (SCD) transplants. We paid particular attention to select studies in which the methodology was appropriate and we took into consideration the geographical area. Thirty-two publications were included. Only five studies, all from the USA, reported confounder-adjusted hazard ratios comparing the survival outcomes between ECD and SCD kidney transplant recipients. These five studies confirmed that ECD recipients seemed to have poorer prognosis. From 29 studies reporting appropriate survival curves, we estimated the 5-year pooled nonadjusted survivals for ECD and SCD recipients. The relative differences between the two groups were lower in Europe than in North America, particularly for death-censored graft failure. It is of primary importance to propose appropriate studies for external validation of the ECD criteria in non-US kidney transplant recipients.

Ischemia/reperfusion Injury and its Consequences on Immunity and Inflammation

Ischemia/reperfusion injury (IRI), an inherent component of transplantation, affects organ quality and transplant outcomes. Although the complexity of the pathophysiology is recognized, detailed mechanisms remain unclear, and strategies preventing the consequences of IRI have been challenging. Of critical significance appears the link between IRI, the initiation of innate immune responses, and the (potential) augmentation of adaptive immunity. An improved understanding of those complex mechanisms and interactions may pave the way for more effective treatment strategies.

Kidney donor risk index is a good prognostic tool for graft outcomes in deceased donor kidney transplantation with short, cold ischemic time

BACKGROUND

We performed a retrospective cohort study to determine the prognostic value of standard criteria donor/expanded criteria donor (SCD/ECD) designation, with regard to one-yr GFR and graft survival rate, in a region with short, cold ischemic time (CIT), and how this designation compares with the kidney donor risk index (KDRI) and zero-time kidney biopsies.

METHODS

We reviewed 362 cases of deceased donor kidney transplantation (DDKT). Donor kidneys were classified as SCD or ECD. They were also assessed by the KDRI. Zero-time kidney biopsy was performed in 196 patients, and histologic score was assessed.

RESULTS

Median follow-up duration was 46 months. Forty-two cases (11.6%) used ECD kidneys. The mean CIT was only 4.9 ± 2.7 h. Graft survival rates were not significantly different between ECD and SCD groups. The KDRI showed the best correlation with one-yr estimations of glomerular filtration rate (eGFR) (R(2) = 0.230, p < 0.001), and higher KDRI was associated with a higher risk of graft failure (hazard ratio 2.63, 95% confidence interval 1.01-6.87). However, higher histologic score was not associated with a higher risk of graft failure.

CONCLUSION

KDRI has greater predictive value for short-term outcomes in DDKT with short CIT than the SCD/ECD designation or pathology.

Evolving experience using kidneys from deceased donors with terminal acute kidney injury

BACKGROUND

Kidney transplantation from deceased donors with terminal acute kidney injury (AKI) is not widely accepted.

STUDY DESIGN

Acute kidney injury donor kidneys were defined by a doubling of the donor's admission serum creatinine (SCr) level and a terminal SCr level >2.0 mg/dL before organ recovery.

RESULTS

Over 5.5 years, we transplanted 84 AKI donor kidneys, including 64 kidneys from standard criteria donors (SCD), 11 from expanded criteria donors (ECD), and 9 from donation after cardiac death (DCD) donors. Mean donor age was 36 years (range 15 to 68 years); mean admission and terminal donor SCr levels were 1.25 mg/dL and 3.2 mg/dL, respectively (mean terminal estimated glomerular filtration rate 25.5 mL/minute). With a mean follow-up of 35 months (range 6 to 70 months), actual patient and graft survival rates are 98% and 89%, respectively, which are numerically, but not statistically, higher than concurrent kidney transplants from brain-dead (non-AKI) SCDs at our center. Delayed graft function (DGF) occurred in 34 patients (40%). Mean 1-, 12-, and 24-month SCr levels were 1.8, 1.6, and 1.7 mg/dL, respectively. Delayed graft function was associated with lower 3-year graft survival for non-AKI SCD transplants (68% vs 90%, with and without DGF), but there was no impact of DGF on graft survival for AKI donor kidneys (89% vs 91%).

CONCLUSIONS

Although AKI donor kidneys more commonly have DGF, the higher rate of DGF does not worsen graft outcomes. Kidneys from deceased donors with terminal AKI transplanted into appropriately selected patients have excellent medium-term outcomes and represent a method to safely expand the donor pool.