Outcomes of kidneys from donors after cardiac death: implications for allocation and preservation

Associations between Deceased-Donor Urine Injury Biomarkers and Kidney Transplant Outcomes

Assessment of deceased-donor organ quality is integral to transplant allocation practices, but tools to more precisely measure donor kidney injury and better predict outcomes are needed. In this study, we assessed associations between injury biomarkers in deceased-donor urine and the following outcomes: donor AKI (stage 2 or greater), recipient delayed graft function (defined as dialysis in first week post-transplant), and recipient 6-month eGFR. We measured urinary concentrations of microalbumin, neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), IL-18, and liver-type fatty acid binding protein (L-FABP) from 1304 deceased donors at organ procurement, among whom 112 (9%) had AKI. Each biomarker strongly associated with AKI in adjusted analyses. Among 2441 kidney transplant recipients, 31% experienced delayed graft function, and mean±SD 6-month eGFR was 55.7±23.5 ml/min per 1.73 m(2) In analyses adjusted for donor and recipient characteristics, higher donor urinary NGAL concentrations associated with recipient delayed graft function (highest versus lowest NGAL tertile relative risk, 1.21; 95% confidence interval, 1.02 to 1.43). Linear regression analyses of 6-month recipient renal function demonstrated that higher urinary NGAL and L-FABP concentrations associated with slightly lower 6-month eGFR only among recipients without delayed graft function. In summary, donor urine injury biomarkers strongly associate with donor AKI but provide limited value in predicting delayed graft function or early allograft function after transplant.

New Solutions to Reduce Discard of Kidneys Donated for Transplantation

Kidney transplantation is a cost-saving treatment that extends the lives of patients with ESRD. Unfortunately, the kidney transplant waiting list has ballooned to over 100,000 Americans. Across large areas of the United States, many kidney transplant candidates spend over 5 years waiting and often die before undergoing transplantation. However, more than 2500 kidneys (>17% of the total recovered from deceased donors) were discarded in 2013, despite evidence that many of these kidneys would provide a survival benefit to wait-listed patients. Transplant leaders have focused attention on transplant center report cards as a likely cause for this discard problem, although that focus is too narrow. In this review, we examine the risks associated with accepting various categories of donated kidneys, including discarded kidneys, compared with the risk of remaining on dialysis. With the goal of improving access to kidney transplant, we describe feasible proposals to increase acceptance of currently discarded organs.

Whether or not to accept a deceased donor kidney offer for a pediatric patient

The expansion of the number of children on the deceased donor renal transplant waitlist has far outstripped the supply of organs in most countries, leading to numerous adjustments to increase supply and to maximize the utility of donor organs. The system for organ allocation varies by country based on local laws, priorities, and resources. Adjustments are made to optimize allocation, enhance post-transplant survival benefit, decrease unequal transplant access, and optimize utilization of donated kidneys. Allocation of deceased donor kidneys is based on several criteria; however, the final decision to accept or reject the offered kidney is made by the potential recipient's transplant team (surgeon/nephrologist). Several considerations including assessment of the donor quality, the human leukocyte antigen (HLA) match between the donor and the recipient, numerous recipient factors, the geographical location of the recipient, and the organ all affect the decision to accept the organ or not for a particular recipient. This decision must be made quickly, often on the spot. Maximizing the benefit from this scarce resource raises difficult ethical issues. The philosophies of equity and utility are often competing. In this manuscript, we highlight a representative case that helps to focus on important issues for the pediatric nephrologist to consider while making the decision to accept a deceased donor kidney offer for a particular pediatric patient.

Management of the Potential Organ Donor in the ICU: Society of Critical Care Medicine/American College of Chest Physicians/Association of Organ Procurement Organizations Consensus Statement

This document was developed through the collaborative efforts of the Society of Critical Care Medicine, the American College of Chest Physicians, and the Association of Organ Procurement Organizations. Under the auspices of these societies, a multidisciplinary, multi-institutional task force was convened, incorporating expertise in critical care medicine, organ donor management, and transplantation. Members of the task force were divided into 13 subcommittees, each focused on one of the following general or organ-specific areas: death determination using neurologic criteria, donation after circulatory death determination, authorization process, general contraindications to donation, hemodynamic management, endocrine dysfunction and hormone replacement therapy, pediatric donor management, cardiac donation, lung donation, liver donation, kidney donation, small bowel donation, and pancreas donation. Subcommittees were charged with generating a series of management-related questions related to their topic. For each question, subcommittees provided a summary of relevant literature and specific recommendations. The specific recommendations were approved by all members of the task force and then assembled into a complete document. Because the available literature was overwhelmingly comprised of observational studies and case series, representing low-quality evidence, a decision was made that the document would assume the form of a consensus statement rather than a formally graded guideline. The goal of this document is to provide critical care practitioners with essential information and practical recommendations related to management of the potential organ donor, based on the available literature and expert consensus.

[Renal transplantation using a Maastricht category III non-heartbeating donor: First French experience and review of the literature]

In 2015, Annecy Hospital was the first French hospital to perform non-heartbeating organ donation from a Maastricht category III donor (patient awaiting cardiac arrest after withdrawal of treatment). Non-heartbeating organ donation (NHBD), performed in France since 2006, had initially excluded this category, due to ethical questions concerning end of life and treatment withdrawal, as well as technical specificities linked to this procedure. Grenoble University Hospital and Edouard-Herriot Hospital in Lyon then performed the first kidney transplants, with satisfactory outcomes in both recipients. This article presents the details and results of this new experience, challenging both on a deontological and organizational level. Functional outcomes of kidney grafts from NHBD are now well known in the literature and confirm their benefit for patients, with similar results to those from heartbeating donors (HBD). International experiences concerning specifically Maastricht category III NHBD are encouraging and promising.

Update on ischemia-reperfusion injury in kidney transplantation: Pathogenesis and treatment

Ischemia/reperfusion injury is an unavoidable relevant consequence after kidney transplantation and influences short term as well as long-term graft outcome. Clinically ischemia/reperfusion injury is associated with delayed graft function, graft rejection, chronic rejection and chronic graft dysfunction. Ischemia/reperfusion affects many regulatory systems at the cellular level as well as in the renal tissue that result in a distinct inflammatory reaction of the kidney graft. Underlying factors of ischemia reperfusion include energy metabolism, cellular changes of the mitochondria and cellular membranes, initiation of different forms of cell death-like apoptosis and necrosis together with a recently discovered mixed form termed necroptosis. Chemokines and cytokines together with other factors promote the inflammatory response leading to activation of the innate immune system as well as the adaptive immune system. If the inflammatory reaction continues within the graft tissue, a progressive interstitial fibrosis develops that impacts long-term graft outcome. It is of particular importance in kidney transplantation to understand the underlying mechanisms and effects of ischemia/reperfusion on the graft as this knowledge also opens strategies to prevent or treat ischemia/reperfusion injury after transplantation in order to improve graft outcome.

Delayed graft function and the risk of acute rejection in the modern era of kidney transplantation

Delayed graft function (DGF) is commonly considered a risk factor for acute rejection, although this finding has not been uniformly observed across all studies. The link between DGF and acute rejection may have changed over time due to advances in immunosuppression and medical management. Here we conducted a cohort study of 645 patients over 12 years to evaluate the association of DGF and biopsy-proven acute rejection (BPAR) in a modern cohort of kidney transplant recipients. DGF was defined as the need for at least one dialysis session in the first week after kidney transplantation. The 1-, 3-, and 5-year cumulative probabilities of BPAR were 16.0, 21.8, and 22.6% in the DGF group, significantly different from the 10.1, 12.4, and 15.7% in the non-DGF group. In multivariable Cox proportional hazards model, the adjusted relative hazard for BPAR in DGF (vs. no DGF) was 1.55 (95% confidence interval (CI): 1.03, 2.32). This association was generally robust to different definitions of DGF. The relative hazard was also similarly elevated for T-cell- or antibody-mediated BPAR (1.52 (0.92, 2.51) and 1.54 (0.85, 2.77), respectively). Finally, the association was consistent across clinically relevant subgroups. Thus DGF remains an important risk factor for BPAR in a contemporary cohort of kidney transplant recipients. Interventions to reduce the risk of DGF and/or its aftereffects remain of paramount importance to improve kidney transplant outcomes.

Donation after Circulatory Death Renal Allografts--Does Donor Age Greater than 50 Years Affect Recipient Outcomes?

PURPOSE

Donation after circulatory death renal allografts are associated with excellent outcomes. We performed a retrospective chart review to investigate the impact of donor age on postoperative and intermediate term outcomes.

MATERIALS AND METHODS

We compared recipient outcomes of donation after circulatory death allografts from donors older vs younger than 50 years. A total of 118 single donations after circulatory death renal transplants were performed at our institution between July 2006 and September 2013. Outcome variables (creatinine clearance, readmission rate, length of hospital stay, delayed graft function, graft loss and rejection) were compared between the 2 age categories using the Student t-test and the Pearson chi-square test. Independent prognosticators of creatinine clearance at 12 months were assessed with multivariate linear regression modeling.

RESULTS

Mean ± SD recipient age was 53.8 ± 14.7 years and 45.8% of donation after circulatory death donors were older than 50 years. Median followup was 21 months (range 1 to 87). Recipients of kidney transplants from donation after circulatory death donors older than 50 years demonstrated lower creatinine clearance at 1 month (mean 50.3 ± 25.3 vs 72.7 ± 31.7 ml per minute, p <0.001), 3 months (62.5 ± 22.9 vs 87.9 ± 36.4, p <0.001) and 1 year (66.2 ± 26.8 vs 87.8 ± 38.7, p = 0.013). However, the 2 groups did not differ with regard to delayed graft function, graft loss, hospital readmissions or length of hospital stay. Multivariate linear regression demonstrated that donor age, recipient age, recipient gender and cold ischemia time were independent predictors of creatinine clearance at 12 months.

CONCLUSIONS

Recipients of allografts from donors older than 50 years showed inferior renal function at 1 year but the 2 groups had similar graft survival and short-term outcomes. Longer followup is required to determine long-term allograft survival.

Kidney donation after circulatory death (DCD): state of the art

The use of kidneys from controlled donation after circulatory death (DCD) donors has the potential to markedly increase kidney transplants performed. However, this potential is not being realized because of concerns that DCD kidneys are inferior to those from donation after brain-death (DBD) donors. The United Kingdom has developed a large and successful controlled DCD kidney transplant program that has allowed for a substantial increase in kidney transplant numbers. Here we describe recent trends in DCD kidney donor activity in the United Kingdom, outline aspects of the donation process, and describe donor selection and allocation of DCD kidneys. Previous UK Transplant Registry analyses have shown that while DCD kidneys are more susceptible to cold ischemic injury and have a higher incidence of delayed graft function, short- and medium-term transplant outcomes are similar in recipients of kidneys from DCD and DBD donors. We present an updated, extended UK registry analysis showing that longer-term transplant outcomes in DCD donor kidneys are also similar to those for DBD donor kidneys, and that transplant outcomes for kidneys from expanded-criteria DCD donors are no less favorable than for expanded-criteria DBD donors. Accordingly, the selection criteria for use of kidneys from DCD donors should be the same as those used for DBD donors. The UK experience suggests that wider international development of DCD kidney transplantation programs will help address the global shortage of deceased donor kidneys for transplantation.

Kidney donation after circulatory death (DCD): state of the art

Ischemia–reperfusion (IR) injury to the kidney occurs in a range of clinically important scenarios including hypotension, sepsis and in surgical procedures such as cardiac bypass surgery and kidney transplantation, leading to acute kidney injury (AKI). Mitochondrial oxidative damage is a significant contributor to the early phases of IR injury and may initiate a damaging inflammatory response. Here we assessed whether the mitochondria targeted antioxidant MitoQ could decrease oxidative damage during IR injury and thereby protect kidney function. To do this we exposed kidneys in mice to in vivo ischemia by bilaterally occluding the renal vessels followed by reperfusion for up to 24 h. This caused renal dysfunction, measured by decreased creatinine clearance, and increased markers of oxidative damage. Administering MitoQ to the mice intravenously 15 min prior to ischemia protected the kidney from damage and dysfunction. These data indicate that mitochondrial oxidative damage contributes to kidney IR injury and that mitochondria targeted antioxidants such as MitoQ are potential therapies for renal dysfunction due to IR injury.

Baseline donor chronic renal injury confers the same transplant survival disadvantage for DCD and DBD kidneys

Histological assessment of baseline chronic kidney injury may discriminate kidneys that are suitable for transplantation, but has not been validated for appraisal of donation after circulatory death (DCD) kidneys. 'Time-zero' biopsies for 371 consecutive, solitary, deceased-donor kidneys transplanted at our center between 2006 and 2010 (65.5% DCD, 34.5% donation after brain death [DBD]) were reviewed and baseline chronic degenerative injury scored using Remuzzi's classification. High scores correlated with donor age and extended criteria donors (42% of donors), but the spectrum of scores was similar for DCD and DBD kidneys. Transplant outcomes for kidneys scoring from 0 to 4 were comparable (1 and 3 year graft survival 95% and 92%), but were much poorer for kidneys scoring ≥5, with 1 year graft survival only 73%, and 12.5% suffering primary nonfunction. Critically, high Remuzzi scores conferred the same survival disadvantage for DCD and DBD kidneys. On multi-variable regression analysis, time-zero biopsy score was the only independent predictor for graft survival, whereas one-year graft estimated glomerular filtration rate (eGFR) correlated with donor age and biopsy score. In conclusion, the relationship between severity of chronic kidney injury and transplant outcome is similar for DCD and DBD kidneys. Kidneys with Remuzzi scores of ≤4 can be implanted singly with acceptable results.

Impact of expanded criteria variables on outcomes of kidney transplantation from donors after cardiac death

INTRODUCTION

To expand the donor pool, kidney transplants are being performed using donors who were previously considered unacceptable. We applied the United Network for Organ Sharing criteria to define expanded criteria donors (ECD) within the donation after cardiac death (DCD) and donation after brain stem death (DBD) cohorts. We compared outcomes of DCD and DBD transplants with and without (standard criteria donor [SCD]) the ECD criteria.

METHODS

This was a single-center retrospective study of all deceased donor transplants from 2004 to 2010 (n=359). Four groups were identified--DBD-SCD (n=154), DBD-ECD (n=93), DCD-SCD (n=78), and DCD-ECD (n=34). Kaplan-Meier analysis of graft and patient survival and multiple regression analysis of 1-year graft function were performed.

RESULTS

One-year and two-year uncensored graft survivals were similar between DCD-ECD and DCD-SCD cohorts (1 year, 90% and 93%; 2 years, 81% and 93% respectively; log-rank test P=0.2). Median estimated glomerular filtration rate (eGFR) was lower in DCD-ECD recipients at 12 months (41 vs. 53 mL/min, P=0.003) and 24 months (33 vs. 54 mL/min, P<0.001) compared with DCD-SCD recipients. Compared with DBD-ECD recipients also at 24 months, DCD-ECD recipients showed a lower graft function (median, eGFR 33 vs. 47 mL/min; P=0.007) but similar graft survival. Expanded criteria donor status (B=-9.7, P=0.01) was associated with a lower 1-year eGFR within the DCD cohort, with donor age (B=-0.42, P=0.002) being the only significant ECD variable.

CONCLUSION

Short-term graft survival in DCD-ECD transplants was comparable to DCD-SCD and DBD-ECD transplants albeit with poorer allograft function at 2 years. Quality-of-life studies are needed to determine the true value of these transplants, particularly when performed to older recipients.

Kidney transplantation from cardiac death donors with terminal acute renal failure

OBJECTIVES

Kidney transplantation from donation after cardiac death (DCD) donors with terminal acute renal failure (ARF) is not widely accepted due to concern about the organ quality. Here we report our initial clinical outcomes of kidney transplantation from DCD donors with ARF.

MATERIALS AND METHODS

The results of 29 kidney transplants from ARF DCD donors were compared with those of 60 kidney transplants from non-ARF DCD donors performed at our center from August 2011 to March 2013.

RESULTS

There was no difference in the incidence of delayed graft function and acute rejection between ARF and non-ARF kidneys (27.6% vs 16.7%, 10.3% vs 8.3%, respectively). Estimated glomerular filtration rate at 12 months was similar between ARF and non-ARF kidneys. With a mean follow-up of 18 months (range 7 to 26 months), actual patient and graft survival rates for ARF DCD recipients were 100% and 96.6%, respectively, which were similar to those of the control group of kidney transplants from non-ARF kidneys (98.3% and 95.0%).

CONCLUSIONS

Kidneys from DCD donors with terminal ARF have excellent short-term outcomes and may represent another potential method to safely expand the donor pool.

Expanded criteria donor and donation after circulatory death renal allografts in the West of Scotland: Their place in the kidney allocation process

INTRODUCTION

Due to the rising disparity between demand and availability, organs from expanded criteria donors (ECD) and donors after determination of circulatory death (DCD) are increasingly used. The purpose of this study was to report outcomes in recipients of ECD and DCD renal allografts from a single centre.

METHODS

A retrospective analysis from a single centre for all renal transplants performed between 2001 and 2010 inclusive was undertaken. SCD (standard criteria donor) and ECD organs were compared, as were DCD and DBD (donation after determination of brain stem death) organs. Baseline data and predefined standard transplant outcomes were collected and compared using appropriate statistical tests. P < 0.05 was defined as significant.

RESULTS

729 renal transplants were performed. Comparing ECD to SCD organs, there was a significant difference in graft survival between groups (logrank for trend, p = 0.032) with ECD organs doing worse than SCD organs. Short-term outcomes showed a similar disparity with a higher 1-year post-transplant creatinine and delayed graft function (DGF) rate in ECD grafts. Nevertheless, outcomes were still clinically acceptable. When comparing DCD to DBD organs, no such differences were apparent, with DCD organs appearing to perform at least as well as DBD organs. In our cohort, unlike some previous studies, DGF rates were similar in both DCD and DBD groups.

CONCLUSIONS

Although ECD organs perform less well than SCD organs, outcomes are still acceptable and our results support their continuing use. When considering DCD organs, our data support the view that they should no longer be necessarily regarded as marginal grafts. Our low DGF rates are perhaps explained by local factors contributing to a short CIT.

Outcome and cost analysis of induction immunosuppression with IL2Mab or ATG in DCD kidney transplants

BACKGROUND

Kidney transplantation from DCD now represents a significant part of the overall transplant activity in the UK. Outcome of different induction immunosuppression regimes and related cost benefit analysis has been reported by very few studies.This is a single centre study on frequency-matched patients who received a DCD kidney transplant between August 2007 and August 2009.

METHODS

Data on 45 patients divided in 2 groups were collected prospectively and analyzed retrospectively. Group A (24 patients) received IL2Mab and Group B (21 patients) ATG as induction immunosuppression. Patient and graft survival were similar in both groups.

RESULTS

In the ATG-induced group, there was a significant lower rate of DGF, BPAR, and infections requiring readmission.A cost analysis was performed including all immunosuppression-related costs, and it has shown remarkable savings in the ATG-induced group.

CONCLUSION

Considering that the number of DCD kidney transplants is destined to rise in the UK, we believe that ATG is a valid option to continue optimizing outcomes of DCD kidney transplant. In our experience, ATG proved to be safe, effective, and contributed to significant cost savings.

Effect of autologous adipose-derived stem cells in renal cold ischemia and reperfusion injury

OBJECTIVE

The aim of this study was to investigate the effect of autologous adipose-derived stem cells (ADSCs) on renal cold ischemia and reperfusion (I/R) injury via intravenous infusion on rats.

METHODS

A renal cold I/R injury rat model was established. Rats were equally randomized into Sham group, Cold I/R group (cold I/R plus culture medium only), and ADSC-treated group (cold I/R plus immediate intrarenal administration of 2 × 10(6) autologous ADSCs, followed by intravenous autologous ADSCs 6 hours after reperfusion). All rats were killed 24 hours after the I/R procedure.

RESULTS

Serum creatinine levels were significantly reduced in the ADSC-treated group compared with the Cold I/R group (P < .01). The renal tissue in the ADSC-treated group had well conserved renal architecture compared with the Cold I/R group. The mRNA expression of tumor necrosis factor α was significantly lower and Bcl-2 was higher in the ADSC-treated group than in the Cold I/R group (P < .05).

CONCLUSIONS

Autologous ADSC infusions ameliorated renal damage undergoing cold I/R injury and improved the renal function, partly through inhibiting inflammatory reactions and reducing apoptosis.

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.

Functional status and survival after kidney transplantation

BACKGROUND

Older patients constitute a growing proportion of U.S. kidney transplant recipients and often have a high burden of comorbidities. A summary measure of health such as functional status might enable transplant professionals to better evaluate and counsel these patients about their prognosis after transplant.

METHODS

We linked United Network for Organ Sharing registry data about posttransplantation survival with pretransplantation functional status data (physical function [PF] scale of the Medical Outcomes Study Short Form-36) among individuals undergoing kidney transplant from June 1, 2000 to May 31, 2006. We examined the relationship between survival and functional status with multivariable Cox regression, adjusted for age. Using logistic regression models for 3-year survival, we also estimated the reduction in deaths in the hypothetical scenario that recipients with poor functional status in this cohort experienced modest improvements in function.

RESULTS

The cohort comprised 10,875 kidney transplant recipients with a mean age of 50 years; 14% were ≥65. Differences in 3-year mortality between highest and lowest PF groups ranged from 3% among recipients <35 years to 14% among recipients ≥65 years. In multivariable Cox regression, worse PF was associated with higher mortality (hazard ratio, 1.66 for lowest vs. highest PF quartiles; P<0.001). Interactions between PF and age were nonsignificant. We estimated that 11% fewer deaths would occur if kidney transplant recipients with the lowest functional status experienced modest improvements in function.

CONCLUSIONS

Across a wide age range, functional status was an independent predictor of posttransplantation survival. Functional status assessment may be a useful tool with which to counsel patients about posttransplantation outcomes.

Glutathione S-transferase iso-enzymes in perfusate from pumped kidneys are associated with delayed graft function

Accurate and reliable assessment tools are needed in transplantation. The objective of this prospective, multi-center study was to determine the associations of the alpha and pi iso-enzymes of glutathione S-transferase (GST), measured from perfusate solution at the start and end (base and post) of kidney allograft machine perfusion, with subsequent delayed graft function (DGF). We also compared GST iso-enzyme perfusate levels from discarded versus transplanted kidneys. A total of 428 kidneys were linked to outcomes as recorded by the United Network of Organ Sharing. DGF, defined as any dialysis in the first week of transplant, occurred in 141 recipients (32%). Alpha- and pi-GST levels significantly increased during machine perfusion. The adjusted relative risks (95% confidence interval) of DGF with each log-unit increase in base and post pi-GST were 1.14 (1.0-1.3) and 1.36 (1.1-1.8), respectively. Alpha-GST was not independently associated with DGF. There were no significant differences in GST values between discarded and transplanted kidneys, though renal resistance was significantly higher in discarded kidneys. We found pi-GST at the end of machine perfusion to be independently associated with DGF. Further studies should elucidate the utility of GST for identifying injured kidneys with regard to organ allocation, discard and recipient management decisions.

Standardized deceased donor kidney donation rates in the UK reveal marked regional variation and highlight the potential for increasing kidney donation: a prospective cohort study†

Background

The UK has implemented a national strategy for organ donation that includes a centrally coordinated network of specialist nurses in organ donation embedded in all intensive care units and a national organ retrieval service for deceased organ donors. We aimed to determine whether despite the national approach to donation there is significant regional variation in deceased donor kidney donation rates.

Methods

The UK prospective audit of deaths in critical care was analysed for a cohort of patients who died in critical care between April 2010 and December 2011. Multivariate logistic regression was used to identify the factors associated with kidney donation. The logistic regression model was then used to produce risk-adjusted funnel plots describing the regional variation in donation rates.

Results

Of the 27 482 patients who died in a critical care setting, 1528 (5.5%) became kidney donors. Factors found to influence donation rates significantly were: type of critical care [e.g. neurointensive vs general intensive care: OR 1.53, 95% confidence interval (CI) 1.34–1.75, P<0.0001], patient ethnicity (e.g. ‘Asian’ vs ‘white’: OR 0.17, 95% CI 0.11–0.26, P<0.0001), age (e.g. age >69 vs age 18–39 yr: OR 0.2, 0.15–0.25, P<0.0001), and cause of death [e.g. ‘other’ (excluding ‘stroke’ and ‘trauma’) vs ‘trauma’: OR 0.04, 95% CI 0.03–0.05, P<0.0001]. Despite correction for these variables, kidney donation rates for the 20 UK kidney donor regions showed marked variation. The overall standardized donation rate ranged from 3.2 to 7.5%. Four regions had donation rates of >2 standard deviations (sd) from the mean (two below and two above). Regional variation was most marked for donation after circulatory death (DCD) kidney donors with 9 of the 20 regions demonstrating donation rates of >2 sd from the mean (5 below and 4 above).

Conclusions

The marked regional variation in kidney donation rates observed in this cohort after adjustment for factors strongly associated with donation rates suggests that there is considerable scope for further increasing kidney donation rates in the UK, particularly DCD.

Postoperative care/critical care of the transplant patient

Critical care of the general surgical patient requires synthesis of the patient's physiology, intraoperative events, and preexisting comorbidities. Evaluating an abdominal solid-organ transplant recipient after surgery adds a new dimension to clinical decisions because the transplanted allograft has undergone its own physiologic challenges and now must adapt to a new environment. This donor-recipient interaction forms the foundation for assessment of early allograft function (EAF). The intensivist must accurately assess and support EAF within the context of the recipient's current physiology and preexisting comorbidities. Optimizing EAF is essential because allograft failure is a significant predictor of recipient morbidity and mortality.

Incidence and distribution of transplantable organs from donors after circulatory determination of death in U.S. intensive care units

RATIONALE

All U.S. acute care hospitals must maintain protocols for recovering organs from donors after circulatory determination of death (DCDD), but the numbers, types, and whereabouts of available organs are unknown.

OBJECTIVES

To assess the maximal potential supply and distribution of DCDD organs in U.S. intensive care units.

METHODS

We conducted a population-based cohort study among a randomly selected sample of 50 acute care hospitals in the highest-volume donor service area in the United States. We identified all potentially eligible donors dying within 90 minutes of the withdrawal of life-sustaining therapy from July 1, 2008 to June 30, 2009.

MEASUREMENTS AND MAIN RESULTS

Using prespecified criteria, potential donors were categorized as optimal, suboptimal, or ineligible to donate their lungs, kidneys, pancreas, or liver. If only optimal DCDD organs were used, the deceased donor supplies of these organs could increase by up to 22.7, 8.9, 7.4, and 3.3%, respectively. If optimal and suboptimal DCDD organs were used, the corresponding supply increases could be up to 50.0, 19.7, 18.5, and 10.9%. Three-quarters of DCDD organs could be recovered from the 17.2% of hospitals with the highest annual donor volumes-typically those with trauma centers and more than 20 intensive care unit beds.

CONCLUSIONS

Universal identification and referral of DCDD could increase the supply of transplantable lungs by up to one-half, and would not increase any other organ supply by more than one-fifth. The marked clustering of DCDD among a small number of identifiable hospitals could guide targeted interventions to improve DCDD identification, referral, and management.

Does national sharing of kidneys donated after cardiac death lead to poorer outcomes?

BACKGROUND

Kidneys donated after cardiac death (DCD) represent an increasing proportion of transplant activity. There have been concerns that wider sharing of these kidneys increases the cold ischemic time (CIT) and leads to poorer outcomes.

METHODS

DCD kidney transplantation was implemented in Scotland in 2005, with each center transplanting locally donated kidneys. A national sharing scheme of DCD kidneys was introduced in 2007, whereby kidneys are shared between the 2 renal transplant centers in the country. A single national multiorgan retrieval team carries out retrievals and kidneys are shipped directly to the 2 units. Donor and recipient demographic data, cold ischemic time, and outcome data were prospectively collected and compared within each center and between centers pre- and postintroduction of the sharing policy.

RESULTS

Since 2005, 152 DCD kidney transplants have been performed. Since 2007, 68 kidneys were shared between the centers. Recipient demographics were comparable before and after the introduction for the sharing scheme. The CIT was significantly higher in Glasgow (14.30 ± 3.79 hours) compared with Edinburgh (10.72 ± 2.99 hours; P < .001, one-way analysis of variance [ANOVA] prior to the introduction of the sharing scheme. Following the implementation of kidney sharing, there was no significant difference in CIT between Glasgow and Edinburgh (10.50 ± 3.34 hours vs 10.53 ± 2.71 hours). A significant reduction in the CIT in Glasgow was noted after sharing was instituted (from 14.30 ± 3.79 hours to 10.50 ± 3.34 hours, P < .001, one-way ANOVA). Patient and graft survivals, acute rejection, and delayed graft function as well as 1-year renal function were comparable in both centers before and after the introduction of the scheme.

CONCLUSION

Wider sharing of DCD kidneys should be encouraged, as it does not compromise clinical outcomes. A transparent and well-established sharing agreement, with no delays in the offering of DCD kidneys, may lead to an improvement in CIT.

Summary of FDA workshop on ischemia reperfusion injury in kidney transplantation

The Food and Drug Administration (FDA) held an open public workshop in September 2011 to discuss the current state of science related to the effects of ischemia reperfusion injury (IRI) on outcomes in kidney transplantation. Topics included the development of IRI and delayed graft function (DGF), histology and biomarkers, donor factors, recipient factors, organ quality and organ preservation by means of cold storage solutions or machine perfusion. Various mechanisms of injury and maladaptive response to IRI were discussed as potential targets of intervention. Animal models evaluating specific pathophysiological pathways were presented, as were the limitations of extrapolating animal results to humans. Clinical trials of various drug products administered in the peri-transplant period were summarized; a few demonstrated early improvements in DGF, but none demonstrated an improvement in late graft function. Clinical trial design for IRI and DGF were also discussed.

Improvements in kidney transplantation from donors after cardiac death

To reduce the growing waiting list for kidney transplantation, we explored the limits of kidney transplantation from donors after cardiac death by liberally accepting marginal donor kidneys for transplantation. As the percentage of primary non-function (PNF) increased, we evaluated our transplantation program and implemented changes to reduce the high percentage of PNF in 2005, followed by a second evaluation over the period 2006-2009. Recipients of a kidney from a donor after cardiac death between 1998 and 2005 were analyzed, with PNF as outcome measure. During the period 2002-2005, the percentage of PNF increased and crossed the upper control limits of 12% which was considered as unacceptably high. After implementation of changes, this percentage was reduced to 5%, without changing the number of kidney transplantations from donors after cardiac death. Continuous monitoring of the quality of care is essential as the boundaries of organ donation and transplantation are sought. Meticulous donor, preservation, and recipient management make extension of the donor potential possible, with good results for the individual recipient. Liberal use of kidneys from donors after cardiac death may contribute to a reduction in the waiting list for kidney transplantation and dialysis associated mortality.

Effect of donor age and cold storage time on outcome in recipients of kidneys donated after circulatory death in the UK: a cohort study

BACKGROUND

Use of kidneys donated after controlled circulatory death has increased the number of transplants undertaken in the UK but there remains reluctance to use kidneys from older circulatory-death donors and concern that kidneys from circulatory-death donors are particularly susceptible to cold ischaemic injury. We aimed to compare the effect of donor age and cold ischaemic time on transplant outcome in kidneys donated after circulatory death versus brain death.

METHODS

We used the UK transplant registry to select a cohort of first-time recipients (aged ≥ 18 years) of deceased-donor kidneys for transplantations done between Jan 1, 2005, and Nov 1, 2010. We did univariate comparisons of transplants from brain-death donors versus circulatory-death donors with χ tests for categorical data and Wilcoxon tests for non-parametric continuous data. We used Kaplan-Meier curves to show graft survival. We used Cox proportional hazards regression to adjust for donor and recipient factors associated with graft-survival with tests for interaction effects to establish the relative effect of donor age and cold ischaemia on kidneys from circulatory-death and brain-death donors.

FINDINGS

6490 deceased-donor kidney transplants were done at 23 centres. 3 year graft survival showed no difference between circulatory-death (n=1768) and brain-death (n=4127) groups (HR 1·14, 95% CI 0·95-1·36, p=0·16). Donor age older than 60 years (compared with <40 years) was associated with an increased risk of graft loss for all deceased-donor kidneys (2·35, 1·85-3·00, p<0·0001) but there was no increased risk of graft loss for circulatory-death donors older than 60 years compared with brain-death donors in the same age group (p=0·30). Prolonged cold ischaemic time (>24 h vs <12 h) was not associated with decreased graft survival for all deceased-donor kidneys but was associated with poorer graft survival for kidneys from circulatory-death donors than for those from brain-death donors (2·36, 1·39-4·02, p for interaction=0·004).

INTERPRETATION

Kidneys from older circulatory-death donors have equivalent graft survival to kidneys from brain-death donors in the same age group, and are acceptable for transplantation. However, circulatory-death donor kidneys tolerate cold storage less well than do brain-death donor kidneys and this finding should be considered when developing organ allocation policy.

FUNDING

UK National Health Service Blood and Transplant; Cambridge National Institute for Health Research Biomedical Research Centre.

Influence of delayed graft function and acute rejection on outcomes after kidney transplantation from donors after cardiac death

BACKGROUND

Delayed graft function (DGF) and acute rejection (AR) exert an adverse impact on graft outcomes after kidney transplantation using organs from donation after brain-stem death (DBD) donors. Here, we examine the impact of DGF and AR on graft survival in kidney transplants using organs from donation after cardiac death (DCD) donors.

METHODS

We conducted a single-center retrospective study of DCD and DBD donor kidney transplants. We compared 1- and 4-year graft and patient survival rates, as well as death-censored graft survival (DCGS) rates, between the two groups using univariate analysis, and the impact of DGF and AR on graft function was compared using multivariate analysis.

RESULTS

Eighty DCD and 206 DBD donor transplants were analyzed. Median follow-up was 4.5 years. The incidence of DGF was higher among DCD recipients (73% vs. 27%, P<0.001), and AR was higher among DBD recipients (23% vs. 9%, P<0.001). One-year and 4-year graft survival rates were similar (DCD 94% and 79% vs. DBD 90% and 82%). Among recipients with DGF, the 4-year DCGS rate was better for DCD recipients compared with DBD recipients (100% vs. 92%, P=0.04). Neither DGF nor AR affected the 1-year graft survival rate in DCD recipients, whereas in DBD recipients, the 1-year graft survival rate was worse in the presence of DGF (88% vs. 96%, P=0.04) and the 4-year DCGS rate was worse in the presence of AR (88% vs. 96%, P=0.04).

CONCLUSION

Despite the high incidence of DGF, medium-term outcomes of DCD kidney transplants are comparable to those from DBD transplants. Short-term graft survival from DCD transplants is not adversely influenced by DGF and AR, unlike in DBD transplants.

Does expanded criteria donor status modify the outcomes of kidney transplantation from donors after cardiac death?

The outcomes of kidney transplants that simultaneously exhibit donation after cardiac death (DCD) and expanded criteria donor (ECD) characteristics have not been well studied. We examined the outcomes of DCD versus non-DCD kidney transplants as a function of ECD status and the kidney donor risk index (KDRI). A cohort study of 67 816 deceased donor kidney transplant recipients (KTR), including 562 ECD/DCD KTR, from January 1, 2000 to December 31, 2009 was conducted using the Scientific Registry of Transplant Recipients. In a multivariable Cox proportional hazards model, the modestly increased risk of total graft failure in DCD versus non-DCD KTR was not significantly modified by ECD status (hazard ratio1.07 [95% CI: 1.01, 1.15] for non-ECD vs. 1.21 [95% CI: 1.04, 1.40] for ECD, p for interaction = 0.14).Moreover, the hazard ratios did not significantly vary by KDRI quintiles (p = 0.40). Similar trends were seen for death-censored graft failure and death with graft function. In conclusion, ECD status or higher KDRI score did not appreciably increase the relative hazard of adverse graft and patient outcomes in DCD KTR. These findings suggest that the judicious use of ECD/DCD donor kidneys may be an appropriate strategy to expand the donor pool.

Impact of donor age on long-term outcomes after delayed graft function: 10-year follow-up

Delayed graft function (DGF) has a negative impact on graft survival in donation after brain death (DBD) but not for donation after cardiac death (DCD) kidneys. However, older donor age is associated with graft loss in DCD transplants. We sought to examine the interaction between donor age and DGF in DBD kidneys. This is a single-center, retrospective review of 657 consecutive DBD recipients transplanted between 1990 and 2005. We stratified the cohort by decades of donor age and studied the association between DGF and graft failure using Cox models. The risk of graft loss associated with DGF was not significantly increased for donor age below 60 years (adjusted hazard ratio [aHR] 1.12, 1.51, and 0.90, respectively, for age <40, 41-50 and 51-60 years) but significantly increased after 60 years (aHR 2.67; P = 0.019). Analysis of death-censored graft failure yielded similar results for donor age below 60 years and showed a substantially increased risk with donors above 60 years (aHR 6.98, P = 0.002). This analysis reveals an unexpectedly high impact of older donor age on the association between DGF and renal transplant outcomes. Further research is needed to determine the best use of kidneys from donors above 60 years old, where DGF is expected.

The conditioning effect of ex vivo normothermic perfusion in an experimental kidney model

BACKGROUND

A short period of isolated normothermic perfusion (NP) can be used to improve the condition of the kidney after periods of warm and cold ischemic injury. However, the mechanisms underlying this beneficial effect have not been determined.

MATERIALS AND METHODS

Porcine kidneys were retrieved after 10 min of warm ischemic injury and stored by either static cold storage (CS) for 24 h (control) or CS for 23 h followed by 1 h of NP at 38°C with leukocyte-depleted autologous blood (NP). After preservation, kidneys in both groups underwent 3 h of ex vivo reperfusion to assess the injury (n = 6).

RESULTS

NP kidneys had significantly lower levels of intrarenal resistance (NP 2.28 ± 1.1 versus control 3.86 ± 1.2 mm Hg/mL/h; P = 0.040), maintained their acid base homeostasis (P = 0.080), and had higher levels of oxygen consumption (NP 42.6 ± 19.5 versus control 20.8 ± 5.7 mL/min/g; P = 0.026) and reduced tubular injury (P = 0.008) compared with kidneys in the control group during reperfusion. There were no significant differences in the levels of inflammatory cytokines (interleukin [IL]-1β, IL-8, or tumor necrosis factor-α; P > 0.05) or in renal function (creatinine clearance NP 2.6 ± 1.3 versus control 3.0 ± 1.5 mL/min/100 g; P = 0.070). However, levels of IL-6 were significantly raised in the NP group after reperfusion (P = 0.016). Levels of heat shock protein 70 were upregulated after 1 h of NP and expression increased during reperfusion to a significantly higher level than in the control group (P = 0.045).

CONCLUSION

Kidneys undergoing a short period of NP had improved metabolic function and less tubular injury compared with static cold-stored kidneys. The increased expression of heat shock protein 70 and IL-6 suggests that NP may upregulate mechanisms that condition the kidney.

Kidney donation after cardiac death

There is continuing disparity between demand for and supply of kidneys for transplantation. This review describes the current state of kidney donation after cardiac death (DCD) and provides recommendations for a way forward. The conversion rate for potential DCD donors varies from 40%-80%. Compared to controlled DCD, uncontrolled DCD is more labour intensive, has a lower conversion rate and a higher discard rate. The super-rapid laparotomy technique involving direct aortic cannulation is preferred over in situ perfusion in controlled DCD donation and is associated with lower kidney discard rates, shorter warm ischaemia times and higher graft survival rates. DCD kidneys showed a 5.73-fold increase in the incidence of delayed graft function (DGF) and a higher primary non function rate compared to donation after brain death kidneys, but the long term graft function is equivalent between the two. The cold ischaemia time is a controllable factor that significantly influences the outcome of allografts, for example, limiting it to < 12 h markedly reduces DGF. DCD kidneys from donors < 50 function like standard criteria kidneys and should be viewed as such. As the majority of DCD kidneys are from controlled donation, incorporation of uncontrolled donation will expand the donor pool. Efforts to maximise the supply of kidneys from DCD include: implementing organ recovery from emergency department setting; improving family consent rate; utilising technological developments to optimise organs either prior to recovery from donors or during storage; improving organ allocation to ensure best utility; and improving viability testing to reduce primary non function.

Ezrin functionality and hypothermic preservation injury in LLC-PK1 cells

Renal epithelial cells from donor kidneys are susceptible to hypothermic preservation injury, which is attenuated when they over express the cytoskeletal linker protein ezrin. This study was designed to characterize the mechanisms of this protection. Renal epithelial cell lines were created from LLC-PK1 cells, which expressed mutant forms of ezrin with site directed alterations in membrane binding functionality. The study used cells expressing wild type ezrin, T567A, and T567D ezrin point mutants. The A and D mutants have constitutively inactive and active membrane binding conformations, respectively. Cells were cold stored (4 °C) for 6-24 h and reperfused for 1h to simulate transplant preservation injury. Preservation injury was assessed by mitochondrial activity (WST-1) and LDH release. Cells expressing the active ezrin mutant (T567D) showed significantly less preservation injury compared to wild type or the inactive mutant (T567A), while ezrin-specific siRNA knockdown and the inactive mutant potentiated preservation injury. Ezrin was extracted and identified from purified mitochondria. Furthermore, isolated mitochondria specifically bound anti-ezrin antibodies, which were reversed with the addition of exogenous recombinant ezrin. Recombinant wild type ezrin significantly reduced the sensitivity of the mitochondrial permeability transition pore (mPTP) to calcium, suggesting ezrin may modify mitochondrial function. In conclusion, the cytoskeletal linker protein ezrin plays a significant role in hypothermic preservation injury in renal epithelia. The mechanisms appear dependent on the molecule's open configuration (traditional linker functionality) and possibly a novel mitochondrial specific role, which may include modulation of mPTP function or calcium sensitivity.

Liver transplantation for hepatitis C from donation after cardiac death donors: an analysis of OPTN/UNOS data

Donation after cardiac death (DCD) liver transplantation is increasing largely because of a shortage of organs. However, there are almost no data that have specifically assessed the impact of using DCD livers for HCV patients. We retrospectively studied adult primary DCD liver transplantation (630 HCV, 1164 non-HCV) and 54 129 donation after brain death (DBD) liver transplantation between 2002 and 2009 using the UNOS/OPTN database. With donation after brain death (DBD) livers, HCV recipients had significantly inferior graft survival compared to non-HCV recipients (p < 0.0001). Contrary to DBD donors, DCD livers used in HCV patients showed no difference in graft survival compared to non-HCV patients (p = 0.5170). Cox models showed DCD livers and HCV disease had poorer graft survival (HR = 1.80 and 1.28, p < 0.0001, respectively). However, the hazard ratio of DCD and HCV interaction was 0.80 (p = 0.02) and these results suggest that DCD livers on HCV disease do not fare worse than DCD livers on non-HCV disease. The graft survival of recent years (2006-2009) was significantly better than that in former years (2002-2005) (p = 0.0482). In conclusion, DCD liver transplantation for HCV disease showed satisfactory outcomes. DCD liver transplantation can be valuable option for HCV related end-stage liver disease.

The aggressive phenotype: center-level patterns in the utilization of suboptimal kidneys

Despite the fact that suboptimal kidneys have worse outcomes, differences in waiting times and wait-list mortality have led to variations in the use of these kidneys. It is unknown whether aggressive center-level use of one type of suboptimal graft clusters with aggressive use of other types of suboptimal grafts, and what center characteristics are associated with an overall aggressive phenotype. United Network for Organ Sharing (UNOS) data from 2005 to 2009 for adult kidney transplant recipients was aggregated to the center level. An aggressiveness score was assigned to each center based on usage of suboptimal grafts. Deceased-donor transplant volume correlated with aggressiveness in lower volume, but not higher volume centers. Aggressive centers were mostly found in regions 2 and 9. Aggressiveness was associated with wait-list size (RR 1.69, 95% CI 1.20-2.34, p = 0.002), organ shortage (RR 2.30, 95% CI 1.57-3.37, p < 0.001) and waiting times (RR 1.75, 95% CI 1.20-2.57, p = 0.004). No centers in single-center OPOs were classified as aggressive. In cluster analysis, the most aggressive centers were aggressive in all metrics and vice versa; however, centers with intermediate aggressiveness had phenotypic patterns in their usage of suboptimal kidneys. In conclusion, wait-list size, waiting times, geographic region and OPO competition seem to be driving factors in center-level aggressiveness.

The case for kidney donation before end-of-life care

Donation after cardiac death (DCD) is associated with many problems, including ischemic injury, high rates of delayed allograft function, and frequent organ discard. Furthermore, many potential DCD donors fail to progress to asystole in a manner that would enable safe organ transplantation and no organs are recovered. DCD protocols are based upon the principle that the donor must be declared dead prior to organ recovery. A new protocol is proposed whereby after a donor family agrees to withdrawal of life-sustaining treatments, premortem nephrectomy is performed in advance of end-of-life management. Since nephrectomy should not cause the donor's death, this approach satisfies the dead donor rule. The donor family's wishes are best met by organ donation, successful outcomes for the recipients, and a dignified death for the deceased. This proposal improves the likelihood of achieving these objectives.

Donor age-specific injury and immune responses

Utilization rates of organs from elderly donors have shown the highest proportional increase during the last decade. Clinical reports support the concept of transplanting older organs. However, the engraftment of such organs has been linked to accelerated immune responses based on ageing changes per se and a proinflammatory environment subsequent to compromised injury and repair mechanism. We analyzed the clinical consequences of transplanting older donor organs and present mechanistic aspects correlating age, injury repair and effects on host immunoresponsiveness.