Association of procurement technique with organ yield and cost following donation after circulatory death

Donation after circulatory death (DCD) could account for the largest expansion of the donor allograft pool in the contemporary era. However, the organ yield and associated costs of normothermic regional perfusion (NRP) compared to super-rapid recovery (SRR) with ex-situ normothermic machine perfusion, remain unreported. The Organ Procurement and Transplantation Network (December 2019 to June 2023) was analyzed to determine the number of organs recovered per donor. A cost analysis was performed based on our institution's experience since 2022. Of 43 502 donors, 30 646 (70%) were donors after brain death (DBD), 12 536 (29%) DCD-SRR and 320 (0.7%) DCD-NRP. The mean number of organs recovered was 3.70 for DBD, 3.71 for DCD-NRP (P < .001), and 2.45 for DCD-SRR (P < .001). Following risk adjustment, DCD-NRP (adjusted odds ratio 1.34, confidence interval 1.04-1.75) and DCD-SRR (adjusted odds ratio 2.11, confidence interval 2.01-2.21; reference: DBD) remained associated with greater odds of allograft nonuse. Including incomplete and completed procurement runs, the total average cost of DCD-NRP was $9463.22 per donor. By conservative estimates, we found that approximately 31 donor allografts could be procured using DCD-NRP for the cost equivalent of 1 allograft procured via DCD-SRR with ex-situ normothermic machine perfusion. In conclusion, DCD-SRR procurements were associated with the lowest organ yield compared to other procurement methods. To facilitate broader adoption of DCD procurement, a comprehensive understanding of the trade-offs inherent in each technique is imperative.

Donation after circulatory death significantly reduces waitlist times while not changing post-heart transplant outcomes: A United Network for Organ Sharing Analysis

BACKGROUND

Recently, several centers in the United States have begun performing donation after circulatory death (DCD) heart transplants (HTs) in adults. We sought to characterize the recent use of DCD HT, waitlist time, and outcomes compared to donation after brain death (DBD).

METHODS

Using the United Network for Organ Sharing database, 10,402 adult (aged >18 years) HT recipients from January 2019 to June 2022 were identified: 425 (4%) were DCD and 9,977 (96%) were DBD recipients. Posttransplant outcomes in matched and unmatched cohorts and waitlist times were compared between groups.

RESULTS

DCD and DBD recipients had similar age (57 years for both, p = 0.791). DCD recipients were more likely White (67% vs 60%, p = 0.002), on left ventricular assist device (LVAD; 40% vs 32%, p < 0.001), and listed as status 4 to 6 (60% vs 24%, p < 0.001); however, less likely to require inotropes (22% vs 40%, p < 0.001) and preoperative extracorporeal membrane oxygenation (0.9% vs 6%, p < 0.001). DCD donors were younger (29 vs 32 years, p < 0.001) and had less renal dysfunction (15% vs 39%, p < 0.001), diabetes (1.9% vs 3.8%, p = 0.050), or hypertension (9.9% vs 16%, p = 0.001). In matched and unmatched cohorts, early survival was similar (p = 0.22). Adjusted waitlist time was shorter in DCD group (21 vs 31 days, p < 0.001) compared to DBD cohort and 5-fold shorter (DCD: 22 days vs DBD: 115 days, p < 0.001) for candidates in status 4 to 6, which was 60% of DCD cohort.

CONCLUSIONS

The community is using DCD mostly for those recipients who are expected to have extended waitlist times (e.g., durable LVADs, status >4). DCD recipients had similar posttransplant early survival and shorter adjusted waitlist time compared to DBD group. Given this early success, efforts should be made to expand the donor pool using DCD, especially for traditionally disadvantaged recipients on the waitlist.

Hypothermic machine perfusion reduces donation after circulatory death liver ischemia-reperfusion injury through the SERPINA3-mediated PI3Kδ/Akt pathway

Hypothermic machine perfusion (HMP) has been demonstrated to be more effective in mitigating ischemia-reperfusion injury (IRI) of donation after circulatory death (DCD) organs than cold storage (CS), yet the underlying mechanism remains obscure. We aimed to propose a novel therapeutic approach to ameliorate IRI in DCD liver transplantation. Twelve clinical liver samples were randomly assigned to HMP or CS treatment and subsequent transcriptomics analysis was performed. By combining in vivo HMP models, we discovered that HMP attenuated inflammation, oxidative stress, and apoptosis in DCD liver through a SEPRINA3-mediated PI3Kδ/AKT signaling cascade. Moreover, in the hypoxia/reoxygenation (H/R) model of BRL-3A, overexpression of SERPINA3 mitigated H/R-induced apoptosis, while SERPINA3 knockdown exacerbated cell injury. Idelalisib (IDE) treatment also reversed the protective effect of SERPINA3 overexpression. Overall, our research provided new insights into therapeutic strategies and identified potential novel molecular targets for therapeutic intervention against DCD liver.

Donation After Circulatory Death Liver Transplantation: Early Challenges, Clinical Improvement, and Future Directions

Donation after circulatory death (DCD) liver allografts remain a widely underutilized source of donor organs for transplantation. Although initially linked with inferior outcomes, DCD liver transplant can achieve excellent patient and graft survival with suitable matching of donor and recipient characteristics, rapid donor recovery and precise donor assessment, and appropriate perioperative management. The advent of clinical liver perfusion modalities promises to redefine the viability parameters for DCD liver allografts and hopefully will encourage more widespread usage of this growing source of donor livers.

The British Transplantation Society guidelines on ethics, law and consent in relation to deceased donors after circulatory death

The British Transplantation Society (BTS) 'Guideline on transplantation from deceased donors after circulatory death' has recently been updated and this manuscript summarises the relevant recommendations from chapters specifically related to law, ethics, donor consent and informing the recipient.

British Transplantation Society guidelines on abdominal organ transplantation from deceased donors after circulatory death

The British Transplantation Society (BTS) 'Guideline on transplantation from deceased donors after circulatory death' has recently been updated and this manuscript summarises the relevant recommendations in abdominal organ transplantation from Donation after Circulatory Death (DCD) donors, encompassing the chapters on liver, kidney, pancreas and islet cell transplantation.

Cardioprotective effect of Interleukin-11 against warm ischemia-reperfusion injury in a rat heart donor model

Shortage of donor organs for heart transplantation is a worldwide problem. Donation after circulatory death (DCD) has been proposed to expand the donor pool. However, in contrast to the donation after brain death that undergoes immediate cold preservation, warm ischemia and subsequent reperfusion injury are inevitable in DCD. It has been reported that interleukin-11 (IL-11) mitigates ischemia-reperfusion injury in rodent models of myocardial infarction and donation after brain death heart transplantation. We hypothesized that IL-11 also offers benefit to warm ischemia in an experimental model of cardiac transplantation that resembles DCD. The hearts of naïve male Sprague Dawley rats (n = 15/group) were procured, subjected to 25-min warm ischemia, and reperfused for 60 min using Langendorff apparatus. IL-11 or saline was administered intravenously before the procurement, added to maintenance buffer, and infused via perfusion during reperfusion. IL-11 group exhibited significantly better cardiac function post-reperfusion. Severely damaged mitochondria was found in the electron microscopic analysis of control hearts whereas the mitochondrial structure was better preserved in the IL-11 treated hearts. Immunoblot analysis using neonatal rat cardiomyocytes revealed increased signal transducer and activator of transcription 3 (STAT3) phosphorylation at Ser727 after IL-11 treatment, suggesting its role in mitochondrial protection. Consistent with expected activation of mitochondrial respiration by mitochondrial STAT3, immunohistochemical staining demonstrated a higher mitochondrial cytochrome c oxidase subunit 2 expression. In summary, IL-11 protects the heart from warm ischemia reperfusion injury by alleviating mitochondrial injury and could be a viable therapeutic option for DCD heart transplantation.

Donation After Cardiac Death: Origins, Current State, and New Directions

Donation after cardiac death (DCD) is a growing source of organs for transplantation. DCD can be challenging to understand due to variations in practice. DCD also holds great potential for ethical compromise making it uncomfortable for many practitioners. This article traces the origin of DCD from the beginnings of organ transplant and lays out the general pattern of the process before touching on advances to this rapidly changing field.

Mitochondrial injury during normothermic regional perfusion (NRP) and hypothermic oxygenated perfusion (HOPE) in a rodent model of DCD liver transplantation

BACKGROUND

Normothermic regional perfusion (NRP) and hypothermic-oxygenated-perfusion (HOPE), were both shown to improve outcomes after liver transplantation from donors after circulatory death (DCD). Comparative clinical and mechanistical studies are however lacking.

METHODS

A rodent model of NRP and HOPE, both in the donor, was developed. Following asystolic donor warm ischemia time (DWIT), the abdominal compartment was perfused either with a donor-blood-based-perfusate at 37 °C (NRP) or with oxygenated Belzer-MPS at 10 °C (donor-HOPE) for 2 h. Livers were then procured and underwent 5 h static cold storage (CS), followed by transplantation. Un-perfused and HOPE-treated DCD-livers (after CS) and healthy livers (DBD) with direct implantation after NRP served as controls. Endpoints included the entire spectrum of ischemia-reperfusion-injury.

FINDINGS

Healthy control livers (DBD) showed minimal signs of inflammation during 2 h NRP and achieved 100% posttransplant recipient survival. In contrast, DCD livers with 30 and 60 min DWIT suffered from greater mitochondrial injury and inflammation as measured by increased perfusate Lactate, FMN- and HMGB-1-levels with subsequent Toll-like-receptor activation during NRP. In contrast, donor-HOPE (instead of NRP) led to significantly less mitochondrial-complex-I-injury and inflammation. Results after donor-HOPE were comparable to ex-situ HOPE after CS. Most DCD-liver recipients survived when treated with one HOPE-technique (86%), compared to only 40% after NRP (p = 0.0053). Following a reduction of DWIT (15 min), DCD liver recipients achieved comparable survivals with NRP (80%).

INTERPRETATION

High-risk DCD livers benefit more from HOPE-treatment, either immediately in the donor or after cold storage. Comparative prospective clinical studies are required to translate the results.

FUNDING

Funding was provided by the Swiss National Science Foundation (grant no: 32003B-140776/1, 3200B-153012/1, 320030-189055/1, and 31IC30-166909) and supported by University Careggi (grant no 32003B-140776/1) and the OTT (grant No.: DRGT641/2019, cod.prog. 19CT03) and the Max Planck Society. Work in the A.G. laboratory was partially supported by the NIH R01NS112381 and R21NS125466 grants.

Screening for mitochondrial function before use-routine liver assessment during hypothermic oxygenated perfusion impacts liver utilization

BACKGROUND

To report on a concept of liver assessment during ex situ hypothermic oxygenated perfusion (HOPE) and its significant impact on liver utilization.

METHODS

An analysis of prospectively collected data on donation after circulatory death (DCD) livers, treated by HOPE at our institution, during a 11-year period between January 2012 and December 2022.

FINDINGS

Four hundred and fifteen DCD Maastricht III livers were offered during the study period in Switzerland, resulting in 249 liver transplants. Of those, we performed 158 DCD III liver transplants at our institution, with 1-year patient survival and death censored graft survival (death with functioning graft) of 87 and 89%, respectively, thus comparable to benchmark graft survivals of ideal DBD and DCD liver transplants (89% and 86%). Correspondingly, graft loss for primary non-function or cholangiopathy was overall low, i.e., 7/158 (4.4%) and 11/158 (6.9%), despite more than 82% of DCD liver grafts ranked high (6-10 points) or futile risk (>10 points) according to the UK-DCD score. Consistently, death censored graft survival was not different between low-, high-risk or futile DCD III livers. The key behind these achievements was the careful development and implementation of a routine perfusate assessment of mitochondrial biomarkers for injury and function, i.e., release of flavin mononucleotide from complex I, perfusate NADH, and mitochondrial CO2 production during HOPE, allowing a more objective interpretation of liver quality on a subcellular level, compared to donor derived data.

INTERPRETATION

HOPE after cold storage is a highly suitable and easy to perform perfusion approach, which allows reliable liver graft assessment, enabling surgeons to make a fact based decision on whether or not to implant the organ. HOPE-treatment should be combined with viability assessment particularly when used for high-risk organs, including DCD livers or organs with relevant steatosis.

FUNDING

This study was supported by the Swiss National Foundation (SNF) grant 320030_189055/1 to PD.

Getting out of the box: the future of the UK donation after circulatory determination of death heart programme

Heart failure imposes a significant burden on all health care systems and has a 5-year mortality of 50%. Heart transplantation and ventricular assist device (VAD) implantation are the definitive therapies for end stage heart disease, although transplantation appears to offer superior long-term survival and quality of life over VAD implantation. Transplantation is limited by a shortage in donor hearts, resulting in considerable waiting list mortality. Donation after circulatory determination of death (DCD) offers a significant uplift in the number of donors for heart transplantation. The outcomes both from the UK and internationally have been exciting, with outcomes at least as good as conventional donation after brain death (DBD) transplantation. Currently, DCD hearts are reperfused using ex-situ machine perfusion (ESMP). Whilst ESMP has enabled the development of DCD transplantation, it comes at significant cost, with the per run cost of approximately GBP £90,000. In-situ perfusion of the heart, otherwise known as thoraco-abdominal normothermic regional perfusion (taNRP) is cheaper, but there are ethical concerns regarding the potential to restore cerebral perfusion in the donor. We must determine whether there is any cerebral circulation during in-situ perfusion of the heart to ensure that it does not invalidate the diagnosis of death and potentially violate the dead donor rule. Besides this, there is a need for a randomised controlled trial to definitively determine whether taNRP offers any clinical advantages over ex-situ machine perfusion. This viewpoint article explores these issues in more detail.

Older liver grafts from donation after circulatory death are associated with impaired survival and higher incidence of biliary non-anastomotic structure

BACKGROUND

Grafts from older donors after circulatory death were associated with inferior outcome in liver transplants in the past. But it has seemed to remain controversial in the last decade, as a result of modified clinical protocols, selected recipients, and advanced technology of organ perfusion and preservation. The present study aimed to examine the impact of older donor age on complications and survival of liver transplant using grafts from donation after circulatory death (DCD).

METHODS

A total of 944 patients who received DCD liver transplantation from 2015 to 2020 were included and divided into two groups: using graft from older donor (aged ≥ 65 years, n = 87) and younger donor (age < 65 years, n = 857). Propensity score matching (PSM) was applied to eliminate selection bias.

RESULTS

A progressively increased proportion of liver transplants with grafts from older donors was observed from 1.68% to 15.44% during the study period. The well-balanced older donor (n = 79) and younger donor (n = 79) were 1:1 matched. There were significantly more episodes of biliary non-anastomotic stricture (NAS) in the older donor group than the younger donor group [15/79 (19.0%) vs. 6/79 (7.6%); P = 0.017]. The difference did not reach statistical significance regarding early allograft dysfunction (EAD) and primary non-function (PNF). Older livers had a trend toward inferior 1-, 2-, 3-year graft and overall survival compared with younger livers, but these differences were not statistically significant (63.1%, 57.6%, 57.6% vs. 76.9%, 70.2%, 67.7%, P = 0.112; 64.4%, 58.6%, 58.6% vs. 76.9%, 72.2%, 72.2%, P = 0.064). The only risk factor for poor survival was ABO incompatible transplant (P = 0.008) in the older donor group. In the subgroup of ABO incompatible cases, it demonstrated a significant difference in the rate of NAS between the older donor group and the younger donor group [6/8 (75.0%) vs. 3/14 (21.4%); P = 0.014].

CONCLUSIONS

Transplants with grafts from older donors (aged ≥ 65 years) after circulatory death are more frequently associated with inferior outcome compared to those from younger donors. Older grafts from DCD are more likely to develop NAS, especially in ABO incompatible cases.

Heart Transplant and Donors After Circulatory Death: A Clinical-Preclinical Systematic Review

INTRODUCTION

Heart transplantation is the treatment of choice for end-stage heart failure. There is a mismatch between the number of donor hearts available and the number of patients awaiting transplantation. Expanding the donor pool is critically important. The use of hearts donated following circulatory death is one approach to increasing the number of available donor hearts.

MATERIALS AND METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines utilizing Pubmed/MEDLINE and Embase. Articles including adult human studies and preclinical animal studies of heart transplantation following donation after circulatory death were included. Studies of pediatric populations or including organs other than heart were excluded.

RESULTS

Clinical experience and preclinical studies are reviewed. Clinical experience with direct procurement, normothermic regional perfusion, and machine perfusion are included. Preclinical studies addressing organ function assessment and enhancement of performance of marginal organs through preischemic, procurement, preservation, and reperfusion maneuvers are included. Articles addressing the ethical considerations of thoracic transplantation following circulatory death are also reviewed.

CONCLUSIONS

Heart transplantation utilizing organs procured following circulatory death is a promising method to increase the donor pool and offer life-saving transplantation to patients on the waitlist living with end-stage heart failure. There is robust ongoing preclinical and clinical research to optimize this technique and improve organ yield. There are also ongoing ethical considerations that must be addressed by consensus before wide adoption of this approach.

Air-ventilated normothermic machine perfusion alleviates hepatic injury from DCD rat through CYP1A2

BACKGROUND

Normothermic machine perfusion (NMP) could provide protection to organs from donation after circulatory death (DCD) before transplantation, and its molecular mechanism remains unclear. Our previous study discovered that the air-ventilated NMP confers a better DCD liver recovery than oxygen-ventilated NMP. The purpose in the current study was to investigate the protective mechanism of air-ventilated NMP in a rat model of DCD liver by metabolomics, and to select biomarker to predict liver function recovery.

MATERIALS AND METHODS

Peroxisome proliferator activator receptor-α (PPARα) agonist or antagonist was administered via the perfusion circuit in the air-ventilated NMP. Perfusate samples were taken for measurements of aminotransferases using standard biochemical methods, tumor necrosis factor-alpha and interleukin-6. Liver biopsies were allocated for detection of metabolomics, PPARα and cytochrome P450 1A2 (CYP1A2).

RESULTS

Metabolomics analysis revealed the significant increased γ-linolenic acid and decreased adrenic acid during the air-ventilated NMP, indicating linoleic acid metabolism pathway was associated with a better DCD liver recovery; as a major enzyme involved in linolenic acid metabolism, CYP1A2 was found correlated with a less inflammation and better liver function with the air-ventilated NMP; PPARα agonist could increase CYP1A2 expression and activity, decrease inflammation response, and improve liver function with the air-ventilated NMP, while PPARα antagonist played the opposite.

CONCLUSION

Air-ventilated NMP confers a better liver recovery from DCD rats through the activated linoleic acid metabolism and CYP1A2 upregulation; CYP1A2 expression and activity might function as biomarker to predict DCD liver function recovery with NMP.

The impact of thoracoabdominal normothermic regional perfusion on early outcomes in donation after circulatory death lung transplantation

Thoracoabdominal normothermic regional perfusion has emerged as an alternative method to procure donation after circulatory death (DCD) hearts, but its impact on concomitantly procured lung allografts remains unclear. The United Network for Organ Sharing database identified 627 DCD donors whose hearts were procured (211 in situ perfused, 416 directly procured) between December 2019 to December 2022. Lung utilization rates were 14.9% (63/422) for in situ perfused donors and 13.8% (115/832) for directly procured donors (p = 0.80). Following transplantation, lung recipients from in situ perfused donors required numerically lower rates of extracorporeal membrane oxygenation (7.7% vs 17.0%, p = 0.26) and mechanical ventilation (34.6% vs 47.2%, p = 0.29) at 72 hours. Six-month post-transplant survival was similar between groups (85.7% vs 89.1%, p = 0.67). These results suggest that the use of thoracoabdominal normothermic regional perfusion in DCD heart procurement may not adversely impact recipients of concomitantly procured lung allografts.

Machine perfusion and the prevention of ischemic type biliary lesions following liver transplant: What is the evidence?

The widespread uptake of different machine perfusion (MP) strategies for liver transplant has been driven by an effort to minimize graft injury. Damage to the cholangiocytes during the liver donation, preservation, or early posttransplant period may result in stricturing of the biliary tree and inadequate biliary drainage. This problem continues to trouble clinicians, and may have catastrophic consequences for the graft and patient. Ischemic injury, as a result of compromised hepatic artery flow, is a well-known cause of biliary strictures, sepsis, and graft failure. However, very similar lesions can appear with a patent hepatic artery and these are known as ischemic type biliary lesions (ITBL) that are attributed to microcirculatory dysfunction rather than main hepatic arterial compromise. Both the warm and cold ischemic period duration appear to influence the onset of ITBL. All of the commonly used MP techniques deliver oxygen to the graft cells, and therefore may minimize the cholangiocyte injury and subsequently reduce the incidence of ITBL. As clinical experience and published evidence grows for these modalities, the impact they have on ITBL rates is important to consider. In this review, the evidence for the three commonly used MP strategies (abdominal normothermic regional perfusion [A-NRP], hypothermic oxygenated perfusion [HOPE], and normothermic machine perfusion [NMP] for ITBL prevention has been critically reviewed. Inconsistencies with ITBL definitions used in trials, coupled with variations in techniques of MP, make interpretation challenging. Overall, the evidence suggests that both HOPE and A-NRP prevent ITBL in donated after circulatory death grafts compared to cold storage. The evidence for ITBL prevention in donor after brain death grafts with any MP technique is weak.

Expanding the Lung Donor Pool: Donation After Circulatory Death, Ex-Vivo Lung Perfusion and Hepatitis C Donors

"Organ shortage remains a limiting factor in lung transplantation. Traditionally, donation after brain death has been the main source of lungs used for transplantation; however, to meet the demand of patients requiring lung transplantation it is crucial to find innovative methods for organ donation. The implementation of extended donors, lung donation after cardiac death (DCD), the use of ex-vivo lung perfusion (EVLP) systems, and more recently the acceptance of hepatitis C donors have started to close the gap between organ donors and recipients in need of lung transplantation. This article focuses on the expansion of donor lungs for transplantation after DCD, the use of EVLP in evaluating extended criteria lungs, and the use of lung grafts from donors with hepatitis C."

Organ donation by Maastricht-III pediatric patients: Recommendations of the Groupe Francophone de Réanimation et Urgences Pédiatriques (GFRUP) and Association des Anesthésistes Réanimateurs Pédiatriques d'Expression Française (ADARPEF). Part II: Specific organizational and technical considerations

A panel of pediatric experts met to develop recommendations on the technical requirements specific to pediatric controlled donation after planned withdrawal of life-sustaining therapies (Maastricht category III). The panel recommends following the withdrawal of life-sustaining therapies protocol usually applied in each unit, which may or may not include immediate extubation. The organ retrieval process should be halted if death does not occur within 3 h of life-support discontinuation. Circulatory arrest is defined as loss of pulsatile arterial pressure and should be followed by a 5-min no-touch observation period. Death is declared based on a list of clinical criteria assessed by two senior physicians. The no-flow time should be no longer than 30, 45, and 90 min for the liver, kidneys, and lungs, respectively. At present, the panel does not recommend pediatric heart donation after death by circulatory arrest. The mean arterial pressure cutoff that defines the start of the functional warm ischemia (FWI) phase is 45 mmHg in patients older than 5 years and/or weighing more than 20 kg. The panel recommends normothermic regional perfusion in these patients. The FWI phase should not exceed 30 and 45 min for retrieving the pancreas and liver, respectively. There is no time limit to the FWI phase for the lungs and kidneys. The panel recommends routine sharing of experience with Maastricht-III donation among all healthcare institutions involved in order to ensure optimal outcome assessment and continuous discussion on the potential difficulties, notably those related to the management of normothermic regional perfusion in small children.

Presence of CD163+ macrophages in DCD kidneys with high DGF reduces the risk for acute cellular rejection in 6 months after kidney transplantation

Acute cellular rejection (ACR) occurs in 10% of renal allograft recipients and is characterized by leukocyte infiltration as observed in needle biopsies. ACR onset is subject to several risk factors, including delayed graft function (DGF). As the impact of DGF on the etiology of ACR remains unclear, this study analyzed the association between presence of leukocyte subsets and ACR onset, in DCD kidney biopsies with extensive DGF following transplantation. Immunohistochemical analysis of protocol biopsies taken 10 days after kidney transplantation revealed that patients with high levels of renal CD163⁺ macrophages have a decreased risk (OR = 0.021, P = 0.008) for ACR in the first 6 months after transplantation. In pre-transplant biopsies of a comparable DCD cohort, with >80% DGF, presence of donor CD163+ macrophages showed no effect on ACR risk. Therefore, leukocyte infiltrate present during the inflammatory response at the time of DGF may contain anti-inflammatory macrophages that exert a protective effect against ACR development.

Donation After Circulatory Death in lung transplantation

The continuing shortage of pulmonary grafts from donors after brain death has led to a resurgence of interest in lung transplantation from donors after circulatory death (DCD). Most lungs from donors after withdrawal from life-sustaining therapy can be recovered rapidly and transplanted directly without ex-vivo assessment in case functional warm ischemic time is limited to 30 to 60 min. The potential of the DCD lung pool is still underutilized and should be maximized in countries with existing legislation. Countries lacking a DCD pathway should be encouraged to develop national ethical, professional, and legal frameworks to address public and professional concerns.

Cytokine mass balance levels in donation after circulatory death donors using hemoadsorption: Case series report

The use of hemadsorption has been purposed to reduce cytokine levels during the reperfusion phase during donation after circulatory death (DCD) programs. This paper aims to describe a cases series of the inflammatory cytokine levels before and after hemadsorption during normothermic reperfusion in DCD donors of liver and kidneys. In this observational pilot paper, we describe 8 DCD donors of liver or kidneys in our center from the year 2018 to 2019. All DCD donor subjects had similar age, were younger than 60 years, without evident critical conditions, no liver or kidney dysfunction known, and they presented with poor neurological outcomes instrumentally and clinically documented. We observed in our patients an interesting reduction of IL-10 and TNF-α levels during the normothermic reperfusion with hemadsorption. We transplanted all livers and kidneys from DCD donors without significant compliances.

Heart Transplant Donor Selection Guidelines: Review and Recommendations

PURPOSE OF REVIEW

The rate of heart transplants, while steadily increasing, is insufficient to meet the growing list of transplant candidates. Marginal donors expand the donor pool. However, criteria used to identify donors greatly vary by institution.

RECENT FINDINGS

The International Society of Heart and Lung Transplant (ISHLT) heart transplant report of 2020 reinforced the importance of donor selection criteria on heart transplant outcomes. Existing literature challenges and reinforces the report's findings. Newer methods, such as donation after circulatory death (DCD), also recontextualize existing donor selection criteria. Transplant prediction models from international databases are poor predictors of individual centers' outcome. Further study is needed to understand associations among donor risk factors, and update the methods used for donor heart selection. In this review, we examine the current literature on extended donor criteria and recommend a model for donor selection.

A multicentre outcome analysis to define global benchmarks for donation after circulatory death liver transplantation

BACKGROUND & AIMS

The concept of benchmarking is established in the field of transplant surgery; however, benchmark values for donation after circulatory death (DCD) liver transplantation are not available. Thus, we aimed to identify the best possible outcomes in DCD liver transplantation and to propose outcome reference values.

METHODS

Based on 2,219 controlled DCD liver transplantations, collected from 17 centres in North America and Europe, we identified 1,012 low-risk, primary, adult liver transplantations with a laboratory MELD score of ≤20 points, receiving a DCD liver with a total donor warm ischemia time of ≤30 minutes and asystolic donor warm ischemia time of ≤15 minutes. Clinically relevant outcomes were selected and complications were reported according to the Clavien-Dindo-Grading and the comprehensive complication index (CCI). Corresponding benchmark cut-offs were based on median values of each centre, where the 75^th-percentile was considered.

RESULTS

Benchmark cases represented between 19.7% and 75% of DCD transplantations in participating centres. The 1-year retransplant and mortality rates were 4.5% and 8.4% in the benchmark group, respectively. Within the first year of follow-up, 51.1% of recipients developed at least 1 major complication (≥Clavien-Dindo-Grade III). Benchmark cut-offs were ≤3 days and ≤16 days for ICU and hospital stay, ≤66% for severe recipient complications (≥Grade III), ≤16.8% for ischemic cholangiopathy, and ≤38.9 CCI points 1 year after transplant. Comparisons with higher risk groups showed more complications and impaired graft survival outside the benchmark cut-offs. Organ perfusion techniques reduced the complications to values below benchmark cut-offs, despite higher graft risk.

CONCLUSIONS

Despite excellent 1-year survival, morbidity in benchmark cases remains high. Benchmark cut-offs targeting morbidity parameters offer a valid tool to assess the protective value of new preservation technologies in higher risk groups and to provide a valid comparator cohort for future clinical trials.

LAY SUMMARY

The best possible outcomes after liver transplantation of grafts donated after circulatory death (DCD) were defined using the concept of benchmarking. These were based on 2,219 liver transplantations following controlled DCD donation in 17 centres worldwide. Donor and recipient combinations with higher risk had significantly worse outcomes. However, the use of novel organ perfusion technology helped high-risk patients achieve similar outcomes as the benchmark cohort.

Donation after circulatory death donors in lung transplantation

Transplantation of any organ into a recipient requires a donor. Lung transplant has a long history of an inadequate number of suitable donors to meet demand, leading to deaths on the waiting list annually since national data was collected, and strict listing criteria. Before the Uniform Determination of Death Act (UDDA), passed in 1980, legally defined brain death in the U.S., all donors for lung transplant came from sudden death victims [uncontrolled Donation after Circulatory Death donors (uDCDs)] in the recipient’s hospital emergency department. After passage of the UDDA, uDCDs were abandoned to Donation after Brain Death donors (DBDs)—perhaps prematurely. Compared to livers and kidneys, many DBDs have lungs that are unsuitable for transplant, due to aspiration pneumonia, neurogenic pulmonary edema, trauma, and the effects of brain death on lung function. Another group of donors has become available—patients with a devastating irrecoverable brain injury that do not meet criteria for brain death. If a decision is made by next-of-kin (NOK) to withdraw life support and allow death to occur by asphyxiation, with NOK consent, these individuals can have organs recovered if death occurs relatively quickly after cessation of mechanical ventilation and maintenance of their airway. These are known as controlled Donation after Circulatory Death donors (cDCDs). For a variety of reasons, in the U.S., lungs are recovered from cDCDs at a much lower rate than kidneys and livers. Ex-vivo lung perfusion (EVLP) in the last decade has had a modest impact on increasing the number of lungs for transplant from DBDs, but may have had a larger impact on lungs from cDCDs, and may be indispensable for safe transplantation of lungs from uDCDs. In the next decade, DCDs may have a substantial impact on the number of lung transplants performed in the U.S. and around the world.

Donation After Circulatory Death: A New Frontier

PURPOSE OF REVIEW

To highlight the current global experience with DCD heart transplantation and explore the evolution of, and compare preservation strategies; examine early clinical outcomes, and discuss the growing use of DCD donors as a new frontier in heart transplantation.

RECENT FINDINGS

The two strategies of DCD heart preservation include NMP using the OCS Heart and TA-NRP followed by either: NMP or CSS. Better understanding the limits of cold ischaemia following TA-NRP will aid in distant procurement. Asystolic warm ischaemia plays an important role in determining immediate post-operative graft function and potential need for mechanical support. Large volume DCD heart transplant units show no difference in survival between DCD and DBD donor heart transplants. In a previously non-utilised source of donor hearts, often viewed as an "unknown frontier" in heart transplantation, DCD hearts are a suitable alternative to brain-dead donor hearts and are likely to remain a permanent part of the heart transplantation landscape. Global uptake is currently increasing, and as understanding of preservation strategies and tolerable ischaemic times improve, utilisation of DCD hearts will continue to grow.

Innovations in Heart Transplantation: A Review

Advanced heart failure affects tens of thousands of people in the United States alone with high morbidity and mortality. Cardiac transplantation offers the best treatment strategy but has been historically limited by donor availability. Recently, there have been significant advances in organ allocation, donor-recipient matching, organ preservation and expansion of the donor pool. The current heart allocation system prioritizes the sickest patients to minimize waitlist mortality. Advances in donor organ selection including predicted heart mass calculations and more sophisticated antibody detection methods for allosensitized patients offer more effective matching of donors and recipients. Innovations in organ preservation such as with organ preservation systems have geographically widened the donor pool. The use of hepatitis C donors is possible with the advent of effective direct-acting antiviral agents to cure donor-transmitted hepatitis C. Finally, further expansion of the donor pool is occurring with the utilization of higher-risk donors with advanced age, medical comorbidities, and left ventricular dysfunction and advances in donation after circulatory death. This review provides an update on the new technologies and transplantation strategies that serve to widen the donor pool and more effectively match donors and recipients so that heart transplant candidates may derive the best outcomes from heart transplantation.

Analysis of risk factors for donation after circulatory death kidney transplantation in Japan

Background

In Japan, donations after circulatory death kidney transplantation are widely performed due to legislation delays. The number of donations after brain death kidney transplantations is increasing, but the target remains unmet. We reviewed the outcomes of donation after circulatory death in Japan.

Methods

We analyzed 2923 deceased kidney transplantations (2239: donation after circulatory death (DCD), 684: donation after brain death (DBD)) performed in Japan from 2000 to 2019. The outcomes of the DCD and DBD groups were compared. We examined the risk factors for graft loss in the DCD group.

Results

The 5-year patient survival and death-censored graft survival rates of the DCD group, obtained by propensity score matching, were 93.6% and 95.2%, respectively, which were equivalent to 94.2% and 93.8%, respectively, obtained in the DBD group. Older donors (≥ 50 years) and prolonged cold ischemia time (≥ 12 h) were risk factors for graft loss; in the presence of these, graft survival was lower in the DCD group.

Conclusions

Older donors and prolonged cold ischemia time reduced graft survival in the DCD group. Proper evaluation of donors and careful preparation for transplant surgery are, therefore, essential to ensure good transplant outcomes.

Perceptions held by healthcare professionals concerning organ donation after circulatory death in an Australian intensive care unit without a local thoracic transplant service: A descriptive exploratory study

BACKGROUND AND OBJECTIVE

Organ donation rates continue to be low in Australia compared with demand. Donation after circulatory death (DCD) has been an important strategy to increase donation rates, facilitated by advances in cardiopulmonary support in intensive care units (ICUs). However, DCD may harbour greater logistical challenges and unfavourable perceptions amongst some ICU healthcare professionals. The aim of this study was to evaluate and understand DCD perceptions at an Australian tertiary hospital.

METHODS

This descriptive exploratory study was conducted at an Australian tertiary hospital. Participants were recruited voluntarily for interview via email and word-of-mouth through the hospital's ICU network. The study used a mixed-methods approach; five close-ended questions were included in the form of Likert scales followed by a semistructured interview with open-ended questions designed to understand participants' perceptions of DCD. Interviews were recorded, transcribed, and thematically analysed.

RESULTS

Sixteen participants were interviewed including eight intensive care doctors, four donation specialist nursing coordinators (DSNCs), and four bedside nurses. Likert responses demonstrated clinicians' support for both DCD and donation after brain death (DBD). Thematic analysis of the transcripts yielded three overarching themes including 'Contextual and environmental influences on DCD decision-making', 'Personal difficulties faced by clinicians in DCD decision-making', and 'Family influences on DCD decision-making'. Significant geographical separation between donation and organ retrieval teams, incurring significant resource utilisation, impacted the donation team's decision-making around DCD, as did a perceived disruption of ICU care to facilitate donation especially for cases where successful DCD was identified to be unlikely.

CONCLUSIONS

Overall, DCD was as acceptable to participants as DBD. However, the geographical separation of this centre meant that logistical barriers potentially impacted the DCD process. Open lines of communication with transplant centres, local resourcing, and a culture of education, experience, and leadership may facilitate the DCD programs where distant retrieval is commonplace.

Implementation of donation after circulatory death kidney transplantation can safely enlarge the donor pool: A systematic review and meta-analysis

BACKGROUND

Donation after circulatory death (DCD) kidney transplantation has been introduced to address organ shortage. However, DCD kidneys are not accepted worldwide due to concerns about inferior quality. To investigate whether these concerns are justified, we performed a systematic review and meta-analysis to investigate DCD graft outcomes compared to donation after brain death (DBD).

MATERIALS AND METHODS

EMBASE, Medline, Cochrane, Web of Science and Google Scholar were searched from database inception until September 2020. Exclusion criteria were studies reporting on pediatric/dual kidney transplants, multi-organ transplants or studies including normothermic perfusion techniques. The primary outcome was graft survival. Secondary outcomes were primary non-function (PNF), delayed graft function (DGF), 3-months biopsy-proven acute rejection (BPAR), 1-year estimated Glomerular Filtration Rate (eGFR), patient survival, and urologic complications. A random-effects model was used for meta-analysis. Meta-regression analysis was performed in case of high between-study heterogeneity.

RESULTS

Fifty-one studies were included, comprising 73,454 DCD and 518,229 DBD recipients. One-year graft loss was increased in DCD recipients (death-censored: risk ratio (RR) 1.10 (95%-confidence interval (CI) 1.04-1.16), all-cause: RR 1.13 (95%-CI 1.08-1.19)). Ten-year graft loss was similar to DBD (death-censored: RR 1.02 (95%-CI 0.92-1.13), all-cause: RR 1.03 (95%-CI 0.94-1.13)). DCD recipients had an increased risk of PNF (RR 1.43 (95%-CI 1.26-1.62)), DGF (RR 2.02 (95%-CI 1.88-2.16)), and 1-year mortality (RR 1.10 (95%-CI 1.01-1.21)). No differences were observed for 3-months BPAR, ureter stenosis/leakage, 1-year eGFR and 10-year mortality.

CONCLUSION

Long-term DCD kidney transplant outcomes are similar to DBD despite a higher risk of PNF, DGF, and a 13% increased risk of graft loss in the first year after transplantation. These results should encourage implementation of DCD programs.

An Audit of Lung Donor Pool: Optimal Current Donation Strategies and the Potential of Novel Time-Extended Donation After Circulatory Death Donation

BACKGROUND

In Australia, increased organ donation and subsequent lung transplantation (LTx) rates have followed enhanced donor identification, referral and management, as well as the introduction of a donation after circulatory death (DCD) pathway. However, the number of patients waiting for LTx still continues to exceed the number of lung donors and the search for further suitable donors is critical.

METHODS

All 2014-2018 Victorian DonateLife hospital deaths after intensive care unit (ICU) admission were analysed retrospectively to quantify unrecognised lung donors using current criteria, as well as novel time-extended (90 mins-24 hrs post-withdrawal) DCD lung donors.

RESULTS

Using standard lung donor eligibility criteria, we identified 473 potential lung donors and a further 122 time-extended DCD potential lung donors among 3,538 patients meeting general eligibility criteria. Detailed review of end-of-life discussions with patient families and the reasons why they were not offered donation revealed several categories of additional lung donors-traditional lung donors missed in current practice (n=2); hepatitis C infected lung donors potentially treatable with direct-acting antivirals (n=14), time-extended DCD lung donors (n=60); donor lungs potentially suitable for transplant with use of ex-vivo lung perfusion (EVLP) (n=7).

CONCLUSION

While the number of lung donor opportunities missed under existing DonateLife donor identification and management processes was limited, a time-extended DCD lung donation pathway could substantially expand the lung donor pool. The use of hepatitis C infected donors, and the possibility of EVLP to solve donor graft assessment or logistic issues, could also provide small additional lung donor opportunities.

Unexpected cardio-circulatory arrest during a brain-dead donor organ retrieval

According to the Maastricht classification category of donation after circulatory death (DCD), type IV DCD refers to brain-dead donors who are re-categorized after unexpected circulatory arrest before donor organ retrieval. Clinical management is challenging, even in intensive care units, where most of this type of organ donation occurs. We report a case of the first successful lung transplantation (LTx) using type IV DCD organ in Taiwan. The recipient's recovery was satisfactory, without acute or chronic organ dysfunction. When unexpected events made the brain-dead donors suffer from sudden onset of cardiac arrest before or during organ donation surgery, immediately switching the retrieval protocol from donation after brain death (DBD) to DCD could expand the donor pool and increase organ supply. The well-prepared and experienced transplant team and prompt protocol switch made this transplant surgery possible.

New Approaches to Donor Selection and Preparation in Heart Transplantation

Purpose of review

With increasing survival of patients with stage D heart failure, the demand for heart transplantation has increased. The supply of donor hearts remains relatively limited. Strategies have been investigated and new technologies have been developed to expand the current donor pool. These new approaches will be discussed herein.

Recent findings

Donor hearts are often considered “marginal” due to risk factors such as older age, size mismatch with the intended recipient, prolonged ischemic time, presence of left ventricular hypertrophy, and hepatitis B/C infection. We reviewed recent data regarding the use of donor hearts with these risk factors and suggest ways to safely liberalize current donor heart acceptance criteria. New technologies such as temperature-controlled transport systems and ex vivo cardiac perfusion methods have also demonstrated promising short-term and intermediate outcomes as compared with routine cold storage, by promoting heart preservation and enabling heart procurement from remote sites with shorter cold ischemic time. Recent use of hearts from donation after circulatory death donors has demonstrated comparable outcomes to conventional donation after brain death, which can further expand the current donor pool.

Summary

Careful selection of “marginal” donor hearts, use of ex vivo cardiac perfusion, and acceptance of hearts after circulatory death may expand our current cardiac donor pool with comparable outcomes to conventional donor selection and preparation methods.

Transplantation of donor hearts after circulatory death using normothermic regional perfusion and cold storage preservation

OBJECTIVES

Hearts donated after circulatory determination of death are usually preserved with normothermic machine perfusion prior to transplantation. This type of preservation is costly, requires bench time adding to warm ischaemia, and does not provide a reliable evaluation of the unloaded donor heart. We report on 4 successful donation after circulatory death (category III) hearts transplanted after thoraco-abdominal normothermic regional perfusion (NRP) and static cold storage.

METHODS

After life sustaining therapy was withdrawn and death was declared, perfusion to thoraco-abdominal organs was restored using extracorporeal circulation via cannulas in the femoral artery and vein and clamping of supra-aortic vessels. After weaning from extracorporeal circulation, cardiac function was assessed. Once approved, the heart was retrieved and stored using classic static cold storage. Data are expressed as median [min-max].

RESULTS

Donor and recipient ages were 44 years [12-60] (n = 4) and 53 years [14-64] (n = 4), respectively. Time from the withdrawal of life sustaining therapy to start of NRP was 22 min [18-31]. Cold storage time was 72 min [35-129]. Thirty-day survival was 100% with a left ventricle ejection fraction of 60% [50-60].

CONCLUSIONS

Donation after circulatory death heart transplantation using thoraco-abdominal NRP and subsequent cold storage preservation for up to 129 min was safe for 4 procedures and could be a way to expand the donor heart pool while avoiding costs of machine preservation.

Kidney transplantation from donation after circulatory death using abdominal normothermic oxygenated circulation: are the outcomes equivalent?

PURPOSE

To increase the pool of kidneys available for transplantation, a renewed interest in donation after circulatory death (DCD) has emerged. This study aims to determine the outcomes of kidney transplantation from DCD after abdominal normothermic oxygenated circulation (ANOR) support.

METHODS

From January 2016 to December 2018, 58 kidneys were implanted from uncontrolled DCD after ANOR support. We performed an observational prospective study, assessing graft function and cumulative incidence of surgical complications. A descriptive analysis was conducted. Potential determinants of the outcomes were evaluated, including donor and receptor gender and age, and warm and cold ischemia times. Regression coefficients (β) and odds ratio (OR) were calculated with 95% confidence intervals. A p-value < 0.05 was considered statistically significant. Statistical analysis was accomplished using Stata 11.0 software.

RESULTS

The median follow-up time was 31.2 months. Delayed graft function (DGF) was evident in 80%, with a mean Cr one month after transplantation of 1.81 mg/dL and 1.33 mg/dL after one year. Primary non-function (PNF) occurred in 5.2% of cases. Male donors were associated with a lower DGF (OR = 0.21, p < 0.05), and a higher donor age was a predictor of poorer graft function at one year (β = - 0.88, p < 0.05). Surgical complications occurred in 31% patients, predominantly vascular. Warm ischemia time superior to 60 min correlated with a higher risk of surgical complications (OR = 11.33, p < 0.05).

CONCLUSION

Kidney transplantation from DCD is a valuable option, allowing an improvement in the balance between patients waiting for a transplant and the available kidneys.

Interobserver Agreement for Classifying Post-liver Transplant Biliary Strictures in Donation After Circulatory Death Donors

INTRODUCTION

Biliary strictures are a common complication of donation after circulatory death (DCD) liver transplantation (LT) and require multiple endoscopic retrograde cholangiopancreatography (ERCP) procedures. Three classification systems, based on cholangiograms, have been proposed for categorizing post-LT biliary strictures. We examined the interobserver agreement for each of the three classifications.

METHODS

DCD LT recipients from 2012 through March 2017 undergoing ERCP for biliary strictures were included in the study. Initial cholangiograms delineating the entire biliary tree prior to endoscopic intervention were selected. One representative cholangiogram was selected from each ERCP. Five interventional endoscopists independently viewed each anonymized cholangiogram and classified the post-LT stricture according to each of the three classification systems. The Ling classification proposes four types of post-LT strictures based on their location. The Lee classification proposes four classes based on location and number of intrahepatic strictures. The binary system classifies strictures into anastomotic or non-anastomotic types. The Krippendorff's alpha reliability estimate was used to grade the strength of agreement as "poor," "fair," "moderate," "good," or "excellent" for values between 0-0.20, 0.21-0.4, 0.41-0.6, 0.61-0.08, and 0.81-1, respectively.

RESULTS

One hundred DCD LT recipients (age 57.07 ± 8.8 years; 71 males) were initially evaluated. Of these, 49 patients who underwent 206 ERCP procedures for biliary strictures were included in the analysis. One hundred thirty-nine cholangiograms were selected and subsequently classified by five endoscopists. Interobserver agreement for post-LT biliary strictures was 0.354 for Ling classification (fair agreement), 0.405 for Lee classification (fair agreement), and 0.421 for the binary classification (moderate agreement). The binary classification provided the least amount of detail regarding the location and number of biliary strictures.

DISCUSSION

The currently available classification systems for assessing post-LT biliary strictures have sub-optimal interobserver agreement. A better-designed classification system is needed for categorizing post-LT biliary strictures.

Modulation of Interleukin-1 and -18 Mediated Injury in Donation after Circulatory Death Mouse Hearts

BACKGROUND

Donation after circulatory death donors (DCD) can expand the donor pool for heart transplantation, which primarily depends on brain death donors. Ischemia and reperfusion injury are inherent to the DCD process. We hypothesize that pharmacologic inhibition of interleukin-1 (IL-1) and/or IL-18 is protective to DCD hearts.

MATERIALS AND METHODS

Following clinical protocol, in-situ ischemia time in control beating-heart donor (CBD) and DCD groups was less than 5 and 40 min, respectively. Wild type (WT) C57Bl6/j, IL-1 receptor type I knockout (IL-1RI-KO), and IL-18 KO mice were used. Hearts were reanimated for 90 min on a Langendorff system with Krebs-Henseleit buffer at 37°C, to assess physiologic parameters. Recombinant IL-1 receptor antagonist (IL-1Ra) and/or IL-18 binding protein (IL-18BP) were added to the Krebs-Henseleit buffer to inhibit IL-1 and/or the IL-18 signaling, respectively.

RESULTS

Developed pressure and ± dP/dt were significantly impaired in the DCD-WT group compared to CBD-WT (P ≤ 0.05). Troponin release was higher in DCD-WT groups. Functional parameters were preserved, and troponin release was significantly less in the DCD knockout groups. Heart function was improved in DCD groups treated with IL-1Ra or IL-18BP compared to the DCD-WT group.

CONCLUSIONS

Heart function was significantly impaired in the DCD-WT group compared to CBD-WT. Genetic deletion or pharmacologic blockade of IL-1 or IL-18 was protective to DCD hearts.

Waiting list mortality and the potential of donation after circulatory death heart transplantations in the Netherlands

Background

With more patients qualifying for heart transplantation (HT) and fewer hearts being transplanted, it is vital to look for other options. To date, only organs from brain-dead donors have been used for HT in the Netherlands. We investigated waiting list mortality in all Dutch HT centres and the potential of donation after circulatory death (DCD) HT in the Netherlands.

Methods

Two different cohorts were evaluated. One cohort was defined as patients who were newly listed or were already on the waiting list for HT between January 2013 and December 2017. Follow-up continued until September 2018 and waiting list mortality was calculated. A second cohort of all DCD donors in the Netherlands (lung, liver, kidney and pancreas) between January 2013 and December 2017 was used to calculate the potential of DCD HT.

Results

Out of 395 patients on the waiting list for HT, 196 (50%) received transplants after a median waiting time of 2.6 years. In total, 15% died while on the waiting list before a suitable donor heart became available. We identified 1006 DCD donors. After applying exclusion criteria and an age limit of 50 years, 122 potential heart donors remained. This number increased to 220 when the age limit was extended to 57 years.

Conclusion

Waiting list mortality in the Netherlands is high. HT using organs from DCD donors has great potential in the Netherlands and could lead to a reduction in waiting list mortality. Cardiac screening will eventually determine the true potential.

Organ donation in the US and Europe: The supply vs demand imbalance

Organ donation and transplantation remain the best and most cost-effective clinical solution for end-stage organ failure. Several agencies across the US and Europe provide legislative, regulatory, and humanitarian services to generate smoother applications in all transplantation processes and donor-recipient relationships. US and European statistics present nine types of grafts, with kidneys being the most transplanted organ worldwide. However, organ shortage, religion, underrepresented minority groups, difficulties in obtaining consent, lack of understanding, and general ethical concerns present challenging barriers to organ donation, reflecting the complexity of graft procurement and allocation. Breaking down these barriers to reduce the organ-supply imbalance requires an appropriate multifaceted approach. Some of the key areas include increasing the potential donor pool and consent rates, apt organ allocation, and improving organ health. Additionally, suitable policies and standardized guidelines for both donors and recipients, alongside educational initiatives, are needed to ensure patient safety and global awareness. Looking forward, novel and effective research plans and initiatives are needed if we are to avoid a colossal supply-demand gap.

DCD donations and outcomes of heart transplantation: the Australian experience

Purpose

There is increasing clinical utilization of hearts from the donation after circulatory death (DCD) pathway with the aim of expanding the donor pool and mitigating the ever-present discrepancy between the inadequate availability of good quality donor hearts and the rising number of patients with end-stage heart failure.

Methods

This article reviews the rationale, practice, logistical factors, and 5-year experience of DCD heart transplantation at St Vincent's Hospital, Sydney.

Findings

Between July 2014 and July 2019, 69 DCD donor retrievals were undertaken resulting in 49 hearts being instrumented on an ex situ normothermic cardiac perfusion device. Seventeen (35%) of these hearts were declined and the remaining 32 (65%) were used for orthotopic DCD heart transplantation. At 5 years of follow-up, the 1-, 3-, and 5-year survival was 96%, 94%, and 94% for DCD hearts compared with 89%, 83%, and 82% respectively for donation after brain death (DBD) hearts (n.s). The immediate post-implant requirement for temporary extra-corporeal membrane oxygenation (ECMO) support for delayed graft function was 31% with no difference in rejection rates when compared with the contemporaneous cohort of patients transplanted with standard criteria DBD hearts.

Summary

DCD heart transplantation has become routine and incorporated into standard clinical practice by a handful of pioneering clinical transplant centres. The Australian experience demonstrates that excellent medium-term outcomes are achievable from the use of DCD hearts. These outcomes are consistent across the other centres and consequently favour a more rapid and wider uptake of heart transplantation using DCD donor hearts, which would otherwise be discarded.

Recipient and allograft survival following donation after circulatory death versus donation after brain death for renal transplantation: A systematic review and meta-analysis

BACKGROUND-OBJECTIVES

Current evidence based on retrospective and prospective studies demonstrates that donation after circulatory death (DCD) grafts are more susceptible to delayed graft function (DGF) than donation after brain death (DBD) grafts. The short- and long-term survival outcomes of the two cohorts are unclear. Therefore, we performed a systematic review and meta-analysis to estimate the patient and allograft survival outcomes for DCD and DBD in renal transplant surgery.

METHODS

Systematic literature searches were conducted by searching various databases. Fixed and random effects models were used to assess the accumulation of evidence over time.

RESULTS

The five-year patient survival rate was significantly better in the DBD than in the DCD cohort. Non-significant differences were observed in 1-, 3- and 10-year patient survival and in the 1-, 3-, 5-, and 10-year graft survival rates between the two cohorts. The acute rejection rate was lower in the DCD cohort than in the DBD cohort. Extended criteria of donor status, delayed graft function and primary non-function were significantly higher in the DCD cohort than in the DBD cohort.

CONCLUSIONS

This study demonstrates that the short- and long-term survival graft and patient benefits are similar between DCD and DBD kidney transplants. Therefore, large, controlled DCD kidney programmes are urgently needed worldwide in order to increase the number of kidney transplants.

Heme oxygenase-1-modified bone marrow mesenchymal stem cells combined with normothermic machine perfusion to protect donation after circulatory death liver grafts

BACKGROUND

Donation after circulatory death (DCD) liver grafts have a poor prognosis after transplantation. We investigated whether the outcome of DCD donor organs can be improved by heme oxygenase 1 (HO-1)-modified bone marrow-derived mesenchymal stem cells (BMMSCs) combined with normothermic machine perfusion (NMP), and explored its underlying mechanisms.

METHODS

BMMSCs were isolated, cultured, and transduced with the HO-1 gene. An NMP system was established. DCD rat livers were obtained, preserved by different methods, and the recipients were divided into 5 groups: sham operation, static cold storage (SCS), NMP, BMMSCs combined with NMP, and HO-1/BMMSCs combined with NMP (HBP) groups. Rats were sacrificed at 1, 7, and 14 days after surgery; their blood and liver tissue samples were collected; and liver enzyme and cytokine levels, liver histology, high-mobility group box 1 (HMGB1) levels in monocytes and liver tissues, and expression of Toll-like receptor 4 (TLR4) pathway-related molecules were evaluated.

RESULTS

After liver transplantation, the SCS group showed significantly increased transaminase levels, liver tissue damage, and shorter survival time. The HBP group showed lower transaminase levels, intact liver morphology, prolonged survival time, and decreased serum and liver proinflammatory cytokine levels. In the NMP and SCS groups, HMGB1 expression in the serum, monocytes, and liver tissues and TLR4 pathway-related molecule expression were significantly decreased.

CONCLUSIONS

HO-1/BMMSCs combined with NMP exerted protective effects on DCD donor liver and significantly improved recipient prognosis. The effect of HO-1/BMMSCs was greater than that of BMMSCs and was mediated via HMGB1 expression and TLR4 pathway inhibition.

Bone marrow mesenchymal stem cells combine with normothermic machine perfusion to improve rat donor liver quality-the important role of hepatic microcirculation in donation after circulatory death

Donation after circulatory death (DCD) can expand the donor pool effectively. A gap remains in outcome between DCD livers and living donor livers, warranting improved DCD liver quality and urgent resolution. Bone marrow mesenchymal stem cells (BMMSCs) can regulate immunity, participate in the anti-inflammatory response, and secrete cytokines. We investigated the effect of BMMSCs combined with normothermic machine perfusion (NMP) on DCD liver quality, and the role of microcirculation therein. Rat thoracic aortas were clipped to obtain DCD livers, and a rat NMP system was established. The DCD livers were grouped by preservation method: normal, static cold storage (SCS), NMP (P), and BMMSCs plus NMP (BP); storage time was up to 8 h. Liver function in outflow perfusate was detected by biochemical methods; liver tissue histopathology was observed by hematoxylin–eosin staining; hepatocyte ultrastructure was observed by transmission electron microscopy; hepatocyte apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling; liver microcirculation–related indicators were detected by immunofluorescence, immunohistochemistry, Western blotting, and enzyme-linked immunosorbent assay. Compared with SCS, P and BP significantly improved liver function and liver histological damage, reduced hepatocyte apoptosis, and repaired hepatocyte mitochondrial damage after 6 h in vitro. BP also significantly inhibited intrahepatic macrophage activation and intercellular adhesion, improved endothelial damage, and significantly improved endothelin 1–nitric oxide balance and microcirculation perfusion. In conclusion, BP can improve DCD liver microcirculation and quality. The mechanism may be the improvement of improve hepatic sinusoidal endothelial injury and microcirculation perfusion by inhibiting macrophage activation and intercellular adhesion.

Successful preservation and transplant of warm ischaemic lungs from controlled donors after circulatory death by prolonged in situ ventilation during normothermic regional perfusion of abdominal organs

OBJECTIVES

Donation after circulatory death (DCD) potentially provides transplantable lungs suitable for a transplant, but in Italy, the need for 20 min of a no-touch period after cardiac arrest for legal declaration of death poses real challenges to organ preservation.

METHODS

This is a single-institution, retrospective study using data collected prospectively between October and December 2017. After the approval of the multidisciplinary DCD study group of Regione Lombardia, Maastricht category III DCD donors became eligible for combined procurement of lungs and abdominal organs. Our group subsequently established a dedicated technical protocol. Our protocol consists of a non-rapid normothermic open-lung procurement process that takes place during abdominal normothermic regional perfusion, namely without pleural topical cooling before the start of pneumoplegia. After the lung is procured according to the technique described in the article, lung function is evaluated by ex vivo lung perfusion, which is run with the low-flow, open atrium, low haematocrit technique.

RESULTS

During the study, we managed 5 controlled DCDs. In 3 cases, the lungs were successfully transplanted. All 3 patients are alive after 1 year, with good respiratory function.

CONCLUSIONS

Our approach resulted in adequate lung preservation and successful transplants without detrimental effects on abdominal organ procurement, confirming the possibility of overcoming the obstacle of a long no-touch period in a DCD setting.

Lung procurement after circulatory death from donor supported on biventricular assist devices and functional assessment with portable normothermic ex vivo organ care system

The criteria for donor organ acceptance are broadening. We describe a successful lung transplantation following donation after circulatory death of extended criteria donor supported with biventricular assist devices. During the redo sternotomy, we used the biventricular assist devices cannulae to perfuse the lungs through the pulmonary artery cannula and draining via the left and right ventricle cannula, significantly minimizing the ischaemic time. Following procurement, we utilized portable ex vivo lung system (Transmedics™ Lung OCS) to optimize, assess and eventually to proceed to a successful transplant.

Risk analysis of extended pancreas donor selection criteria

INTRODUCTION

The success of pancreas transplantation, in combination with a stable number of available allografts has resulted in an increasing waiting list. This study investigated donor potential by expanding age and Body Mass Index (BMI) criteria.

METHODS

All reported donors in the Netherlands between 2013 and 2017 were analysed. Risk assessment of extended criteria donors was done by in-depth analysis of donor reports and calculation of the Pancreas Donor Risk Index (PDRI). The PDRI of these extended criteria donors was compared to standard criteria donors to evaluate the increased risk on graft failure.

RESULTS

A total of 1273 donors were reported. Of these donors, 405 donors were reported as pancreas donor, of which 93 (23%) pancreata were transplanted. Extending age criterion with 5 years could result in additional 40 Donation after Brain Death donors and 37 Donation after Circulatory Death donors reported. In 24 (31%) extended age criteria donors the PDRI was below the upper limit of currently transplanted pancreata. Extending BMI criteria to 35 kg/m² could result in an additional 19 (6%) donors reported.

CONCLUSIONS

Extending BMI criteria could result in a slight increase of reported donors. Extending age criteria increased significantly the number of reported donors. In 24 (31%) of the older donors the PDRI showed a reduced risk compared to currently transplanted pancreata. This study suggest that, if other risk factors are absent, pancreata of extended age and/or BMI criteria donors should be considered for transplantation.

The UK-DCD-Risk-Score - practical and new guidance for allocation of a specific organ to a recipient?

Introduction: Multiple factors contribute to the overall outcome in donation after circulatory death liver transplantation. The majority is however inconsistently reported with various acceptance criteria and thresholds, when to decline a specific graft. Recent improvement in outcome was based on an increased awareness of the cumulative risk, combining donor and recipient parameters, which encouraged the community to accept livers with an overall higher risk. Areas covered: This review pictures the large number of risk factors in this field with a special focus on parameters, which contribute to available prediction models. Next, features of the recently developed UK-DCD-Risk-Score, which led to a significantly impaired graft survival, above a suggested threshold of >10 score points, are discussed. The clinical impact of this new model on the background of other prediction tools with their subsequent limitations is highlighted in a next chapter. Finally, we provide suggestions, how to further improve outcomes in this challenging field of transplantation. Expert opinion: Despite the recent development of new prediction models, including the UK-DCD-Risk-Score, which provides a sufficient prediction of graft loss after DCD liver transplantation, the consideration of other confounders is essential to better understand the overall risk and metabolic liver status to improve the comparability of clinical studies. More uniform definitions and thresholds of individual risk factors are required.

Survival advantage for patients accepting the offer of a circulatory death liver transplant

BACKGROUND & AIMS

Donation after circulatory death (DCD) in the UK has tripled in the last decade. However, outcomes following DCD liver transplantation are worse than for donation after brainstem death (DBD) liver transplants. This study examines whether a recipient should accept a "poorer quality" DCD organ or wait longer for a "better" DBD organ.

METHODS

Data were collected on 5,825 patients who were registered on the elective waiting list for a first adult liver-only transplant and 3,949 patients who received a liver-only transplant in the UK between 1 January 2008 and 31 December 2015. Survival following deceased donor liver transplantation performed between 2008 and 2015 was compared by Cox regression modelling to assess the impact on patient survival of accepting a DCD liver compared to deferring for a potential DBD transplant.

RESULTS

A total of 953 (23%) of the 3,949 liver transplantations performed utilised DCD donors. Five-year post-transplant survival was worse following DCD than DBD transplantation (69.1% [DCD] vs. 78.3% [DBD]; p <0.0001: adjusted hazard ratio [HR] 1.65; 95% CI 1.40-1.94). Of the 5,798 patients registered on the transplant list, 1,325 (23%) died or were removed from the list without receiving a transplant. Patients who received DCD livers had a lower risk-adjusted hazard of death than those who remained on the waiting list for a potential DBD organ (adjusted HR 0.55; 95% CI 0.47-0.65). The greatest survival benefit was in those with the most advanced liver disease (adjusted HR 0.19; 95% CI 0.07-0.50).

CONCLUSIONS

Although DCD liver transplantation leads to worse transplant outcomes than DBD transplantation, the individual's survival is enhanced by accepting a DCD offer, particularly for patients with more severe liver disease. DCD liver transplantation improves overall survival for UK listed patients and should be encouraged.

LAY SUMMARY

This study looks at patients who require a liver transplant to save their lives; this liver can be donated by a person who has died either after their heart has stopped (donation after cardiac death [DCD]) or after the brain has been injured and can no longer support life (donation after brainstem death [DBD]). We know that livers donated after brainstem death function better than those after cardiac death, but there are not enough of these livers for everyone, so we wished to help patients decide whether it was better for them to accept an early offer of a DCD liver than waiting longer to receive a "better" liver from a DBD donor. We found that patients were more likely to survive if they accepted the offer of a liver transplant as soon as possible (DCD or DBD), especially if their liver disease was very severe.

super-rapid recovery in controlled donation after circulatory death liver transplantation

BACKGROUND & AIMS

Although there is increasing interest in its use, definitive evidence demonstrating a benefit for postmortem normothermic regional perfusion (NRP) in controlled donation after circulatory death (cDCD) liver transplantation is lacking. The aim of this study was to compare results of cDCD liver transplants performed with postmortem NRP vs. super-rapid recovery (SRR), the current standard for cDCD.

METHODS

This was an observational cohort study including all cDCD liver transplants performed in Spain between June 2012 and December 2016, with follow-up ending in December 2017. Each donor hospital determined whether organ recovery was performed using NRP or SRR. The propensity scores technique based on the inverse probability of treatment weighting (IPTW) was used to balance covariates across study groups; logistic and Cox regression models were used for binary and time-to-event outcomes.

RESULTS

During the study period, there were 95 cDCD liver transplants performed with postmortem NRP and 117 with SRR. The median donor age was 56 years (interquartile range 45-65 years). After IPTW analysis, baseline covariates were balanced, with all absolute standardised differences <0.15. IPTW-adjusted risks were significantly improved among NRP livers for overall biliary complications (odds ratio 0.14; 95% CI 0.06-0.35, p <0.001), ischaemic type biliary lesions (odds ratio 0.11; 95% CI 0.02-0.57; p = 0.008), and graft loss (hazard ratio 0.39; 95% CI 0.20-0.78; p = 0.008).

CONCLUSIONS

The use of postmortem NRP in cDCD liver transplantation appears to reduce postoperative biliary complications, ischaemic type biliary lesions and graft loss, and allows for the transplantation of livers even from cDCD donors of advanced age.

LAY SUMMARY

This is a propensity-matched nationwide observational cohort study performed using livers recovered from donors undergoing cardiac arrest provoked by the intentional withdrawal of life support (controlled donation after circulatory death, cDCD). Approximately half of the livers were recovered after a period of postmortem in situ normothermic regional perfusion, which restored warm oxygenated blood to the abdominal organs, whereas the remainder were recovered after rapid preservation with a cold solution. The study results suggest that the use of postmortem normothermic regional perfusion helps reduce rates of post-transplant biliary complications and graft loss and allows for the successful transplantation of livers from older cDCD donors.

Age and liver transplantation

The average age of liver transplant donors and recipients has increased over the years. Independent of the cause of liver disease, older candidates have more comorbidities, higher waitlist mortality and higher post-transplant mortality than younger patients. However, transplant benefit may be similar in older and younger recipients, provided older recipients are carefully selected. The cohort of elderly patients transplanted decades ago is also increasingly raising issues concerning long-term exposure to immunosuppression and aging of the transplanted liver. Excellent results can be achieved with elderly donors and there is virtually no upper age limit for donors after brain death liver transplantation. The issue is how to optimise selection, procurement and matching to ensure good results with elderly donors. The impact of old donor age is more pronounced in younger recipients and patients with a high model for end-stage liver disease score. Age matching between the donor and the recipient should be incorporated into allocation policies with a multistep approach. However, age matching may vary depending on the objectives of different allocation policies. In addition, age matching must be revisited in the era of direct-acting antivirals. More restrictive limits have been adopted in donation after circulatory death. Perfusion machines which are currently under investigation may help expand these limits. In living donor liver transplantation, donor age limit is essentially guided by morbidity related to procurement. In this review we summarise changing trends in recipient and donor age. We discuss the implications of older age donors and recipients. We also consider different options for age matching in liver transplantation that could improve outcomes.