Donation after circulatory determination of death: the university of michigan experience with extracorporeal support

Defining the optimal duration for normothermic regional perfusion in the kidney donor: A porcine preclinical study

Kidneys from donation after circulatory death (DCD) are highly sensitive to ischemia-reperfusion injury and thus require careful reconditioning, such as normothermic regional perfusion (NRP). However, the optimal NRP protocol remains to be characterized. NRP was modeled in a DCD porcine model (30 minutes of cardiac arrest) for 2, 4, or 6 hours compared to a control group (No-NRP); kidneys were machine-preserved and allotransplanted. NRP appeared to permit recovery from warm ischemia, possibly due to an increased expression of HIF1α-dependent survival pathway. At 2 hours, blood levels of ischemic injury biomarkers increased: creatinine, lactate/pyruvate ratio, LDH, AST, NGAL, KIM-1, CD40 ligand, and soluble-tissue-factor. All these markers then decreased with time; however, AST, NGAL, and KIM-1 increased again at 6 hours. Hemoglobin and platelets decreased at 6 hours, after which the procedure became difficult to maintain. Regarding inflammation, active tissue-factor, cleaved PAR-2 and MCP-1 increased by 4-6 hours, but not TNF-α and iNOS. Compared to No-NRP, NRP kidneys showed lower resistance during hypothermic machine perfusion (HMP), likely associated with pe-NRP eNOS activation. Kidneys transplanted after 4 and 6 hours of NRP showed better function and outcome, compared to No-NRP. In conclusion, our results confirm the mechanistic benefits of NRP and highlight 4 hours as its optimal duration, after which injury markers appear.

Donation after circulatory death and its expansion in Spain

PURPOSE OF REVIEW

Donation after circulatory death (DCD) is still performed in a limited number of countries. This article summarizes the development of DCD in Spain and presents recent Spanish contributions to gain knowledge on the potential benefits and the practical use of normothermic regional perfusion (nRP).

RECENT FINDINGS

DCD now contributes to 24% of deceased donors in Spain. The development of DCD has been based on an assessment of practices in the treatment of cardiac arrest and end-of-life care to accommodate the option of DCD; the creation of an adequate regulatory framework; and institutional support, professional training and public education. Appropriate posttransplant outcomes have been obtained with organs from both uncontrolled and controlled DCD donors. nRP is increasingly used, with preliminary data supporting improved results compared with other in-situ preservation/recovery approaches. Mobile teams with portable extracorporeal membrane oxygenation devices are making nRP possible in hospitals without these resources. To avoid the possibility of reestablishing brain circulation after the determination of death, a specific methodology has been validated.

SUMMARY

DCD has been successfully developed in Spain following a streamlined process. nRP may become a standard in DCD, although further evidence on the benefits of this technology is eagerly awaited.

Machine perfusion for liver transplantation in the era of marginal organs-New kids on the block

In the face of a critical organ shortage in the Western world, various strategies are employed to expand the donor pool for orthotopic liver transplantation (OLT). Among them is the transplantation of organs from extended criteria donors, a valuable source of liver allografts, however, characterized by potential risks for post-OLT complications and inferior outcomes. In recent years, machine perfusion (MP) of the explanted donor liver as well as regional perfusion techniques has witnessed significant advancements. Here, we aim to discuss different modes of dynamic organ preservation in OLT. These include hypothermic and normothermic MP, hypothermic oxygenated machine perfusion (HOPE), controlled oxygenated rewarming as well as regional perfusion protocols. Over recent years, multiple feasibility trials have demonstrated the clinical prospects of MP. In the context of OLT using organs from extended criteria donors, MP has numerous advantages compared to conventional cold storage, some of which include the preservation and reconditioning of borderline transplantable organs and the viability assessment of high-risk donor allografts. This review aims to address the topic of liver allograft MP, highlighting particularly the current trends in clinical applications and future perspectives. Furthermore, different approaches of liver storage and reconditioning are reviewed in the context of ongoing research.

Systematic review to assess the possibility of return of cerebral and cardiac activity after normothermic regional perfusion for donors after circulatory death

BACKGROUND

Normothermic regional perfusion (NRP) is a novel technique that aids organ recovery from donors after circulatory death (DCDs). However, ethical concerns exist regarding the potential return of spontaneous cerebral and cardiac activity (ROSCCA). This study aimed to determine the likelihood of ROSCCA in NRP-DCDs of abdominal organs.

METHODS

Extracorporeal cardiopulmonary resuscitation (ECPR) for refractory out-of-hospital cardiac arrest (OOHCA) was identified as a comparator for NRP-DCDs and as a validation cohort. A systematic search identified all articles relating to NRP-DCDs and ECPR-OOHCA. Rates of ROSCCA and survival outcomes (ECPR-OOHCA only) were recorded and analysed according to the duration of no perfusion.

RESULTS

In NRP-DCDs, 12 of 410 articles identified by database searching were eligible for inclusion. There were no instances of ROSCCA recorded among 493 donors. In ECPR-OOHCA, eight of 947 screened articles were eligible for inclusion (254 patients). Where the absence of perfusion exceeded 5 min in ECPR-OOHCA, there were no survivors with a favourable neurological outcome.

CONCLUSION

ROSCCA is unlikely following commencement of NRP and has not occurred to date. Strict observance of the 5-min interval following asystole provides satisfactory assurance that ROSCCA will not occur following NRP.

The use of ECMO in ICU. Recommendations of the Spanish Society of Critical Care Medicine and Coronary Units

The use of extracorporeal membrane oxygenation systems has increased significantly in recent years; given this reality, the Spanish Society of Critical Intensive Care Medicine and Coronary Units (SEMICYUC) has decided to draw up a series of recommendations that serve as a framework for the use of this technique in intensive care units. The three most frequent areas of extracorporeal membrane oxygenation systems use in our setting are: as a cardiocirculatory support, as a respiratory support and for the maintenance of the abdominal organs in donors. The SEMICYUC appointed a series of experts belonging to the three working groups involved (Cardiological Intensive Care and CPR, Acute Respiratory Failure and Transplant work group) that, after reviewing the existing literature until March 2018, developed a series of recommendations. These recommendations were posted on the SEMICYUC website to receive suggestions from the intensivists and finally approved by the Scientific Committee of the Society. The recommendations, based on current knowledge, are about which patients may be candidates for the technique, when to start it and the necessary infrastructure conditions of the hospital centers or, the conditions for transfer to centers with experience. Although from a physiopathological point of view, there are clear arguments for the use of extracorporeal membrane oxygenation systems, the current scientific evidence is weak, so studies are needed that define more precisely which patients benefit most from the technique and when they should start.

Heart transplantation after the circulatory death; The ethical dilemma

Donors after brain death (DBD) have been the major source of organ donation due to good perfusion of the organs. However, owing to the mismatch in demand and supply of the organ donors and recipients, donors after circulatory death (DCDDs) has increased recently all over the world. Kidneys, liver, and lungs are being used for transplantation from DCDDs. Recently, heart transplantation from DCDDs has been started, which is under the firestorm of scrutiny by the ethicists. The ethical dilemma revolves around the question whether the donors are actually dead when they are declared dead by cardiocirculatory death criteria for organ procurement. The subsequent literature review addresses all the perspectives by differentiating between the donation methods known as DBDs and DCDDs, explaining the implications of the dead-donor rule on the organ donation pool, and categorizing the determinants of death leading to separation of the arguments under the two methods of donations.

"Super-rapid" Technique in Donation After Circulatory Death Liver Donors: Advantages and Disadvantages

In recent years, donation after circulatory death (DCD) has increased as an option to overcome the organ donor shortage crisis and to decrease the large number of patients on liver transplant waiting lists. The "super-rapid" technique is now the "gold standard" procurement method because of its availability, reproducibility, low cost, and extensive experience. Recently, extracorporeal support has been implemented, with encouraging results. Strict donor acceptance criteria have proven to be essential to optimize the DCD liver graft outcomes and minimize biliary complication rates. In this study we assessed the state of the art of DCD liver transplantation with regard to its development and the actual strategies to prevent graft complications, with aim of expanding the pool of marginal liver donors.

First Scandinavian Protocol for Controlled Donation After Circulatory Death Using Normothermic Regional Perfusion

Background

Donation after circulatory death (DCD) can increase the pool of available organs for transplantation. This pilot study evaluates the implementation of a controlled DCD (cDCD) protocol using normothermic regional perfusion in Norway.

Methods

Patients aged 16 to 60 years that are in coma with documented devastating brain injury in need of mechanical ventilation, who would most likely attain cardiac arrest within 60 minutes after extubation, were eligible. With the acceptance from the next of kin and their wish for organ donation, life support was withdrawn and cardiac arrest observed. After a 5-minute no-touch period, extracorporeal membrane oxygenation for post mortem regional normothermic regional perfusion was established. Cerebral and cardiac reperfusion was prevented by an aortic occlusion catheter. Measured glomerular filtration rates 1 year postengraftment were compared between cDCD grafts and age-matched grafts donated after brain death (DBD).

Results

Eight cDCD were performed from 2014 to 2015. Circulation ceased median 12 (range, 6-24) minutes after withdrawal of life-sustaining treatment. Fourteen kidneys and 2 livers were retrieved and subsequently transplanted. Functional warm ischemic time was 26 (20-51) minutes. Regional perfusion was applied for 97 minutes (54-106 minutes). Measured glomerular filtration rate 1 year postengraftment was not significantly different between cDCD and donation after brain death organs, 75 (65-76) vs 60 (37-112) mL/min per 1.73 m² (P = 0.23). No complications have been observed in the 2 cDCD livers.

Conclusion

A protocol for cDCD is successfully established in Norway. Excellent transplant outcomes have encouraged us to continue this work addressing the shortage of organs for transplantation.

Heparin but not tissue plasminogen activator improves outcomes in donation after circulatory death liver transplantation in a porcine model

Ischemic-type biliary lesions (ITBLs) arise most frequently after donation after circulatory death (DCD) liver transplantation and result in high morbidity and graft loss. Many DCD grafts are discarded out of fear for this complication. In theory, microvascular thrombi deposited during donor warm ischemia might be implicated in ITBL pathogenesis. Herein, we aim to evaluate the effects of the administration of either heparin or the fibrinolytic drug tissue plasminogen activator (TPA) as means to improve DCD liver graft quality and potentially avoid ITBL. Donor pigs were subjected to 1 hour of cardiac arrest (CA) and divided among 3 groups: no pre-arrest heparinization nor TPA during postmortem regional perfusion; no pre-arrest heparinization but TPA given during regional perfusion; and pre-arrest heparinization but no TPA during regional perfusion. In liver tissue sampled 1 hour after CA, fibrin deposition was not detected, even when heparin was not given prior to arrest. Although it was not useful to prevent microvascular clot formation, pre-arrest heparin did offer cytoprotective effects during CA and beyond, reflected in improved flows during regional perfusion and better biochemical, functional, and histological parameters during posttransplantation follow-up. In conclusion, this study demonstrates the lack of impact of TPA use in porcine DCD liver transplantation and adds to the controversy over whether the use of TPA in human DCD liver transplantation really offers any protective effect. On the other hand, when it is administered prior to CA, heparin does offer anti-inflammatory and other cytoprotective effects that help improve DCD liver graft quality. Liver Transplantation 24 665-676 2018 AASLD.

Donors after circulatory death pancreas transplantation

PURPOSE OF REVIEW

The use of organs from donors after circulatory death (DCD) has become standard practice in solid organ transplantation of most abdominal organs and has been used successfully in some centres for pancreas transplantation. Nevertheless, concerns regarding poor graft outcomes and complications remain. This review aims to discuss the current state of DCD pancreas transplantation and the associated outcomes.

RECENT FINDINGS

In many countries, whereas the number of donors after brainstem death (DBD) remains stable, the mean age and BMI have increased making these donors, previously considered to be low risk, now more marginal. Recent meta-analyses have confirmed previous single-centre and registry reports that graft and patient survival after DCD pancreas transplantation are comparable with outcomes using pancreases from DBD donors; DCD pancreas transplantation is now common practice in several countries in Europe, particularly the United Kingdom. Although there have been reports of higher thrombosis rates after DCD pancreas transplantation, the significance of this is difficult to judge as the impact has not been seen in overall graft survival.

SUMMARY

Pancreas transplantation using DCD organs is well tolerated and feasible when other risk factors are minimized. Although there has been some evidence of an increased risk of thrombosis, this has not translated into a significant difference in graft survival.

Canadian Guidelines for Controlled Pediatric Donation After Circulatory Determination of Death-Summary Report

OBJECTIVES

Create trustworthy, rigorous, national clinical practice guidelines for the practice of pediatric donation after circulatory determination of death in Canada.

METHODS

We followed a process of clinical practice guideline development based on World Health Organization and Canadian Medical Association methods. This included application of Grading of Recommendations Assessment, Development, and Evaluation methodology. Questions requiring recommendations were generated based on 1) 2006 Canadian donation after circulatory determination of death guidelines (not pediatric specific), 2) a multidisciplinary symposium of national and international pediatric donation after circulatory determination of death leaders, and 3) a scoping review of the pediatric donation after circulatory determination of death literature. Input from these sources drove drafting of actionable questions and Good Practice Statements, as defined by the Grading of Recommendations Assessment, Development, and Evaluation group. We performed additional literature reviews for all actionable questions. Evidence was assessed for quality using Grading of Recommendations Assessment, Development, and Evaluation and then formulated into evidence profiles that informed recommendations through the evidence-to-decision framework. Recommendations were revised through consensus among members of seven topic-specific working groups and finalized during meetings of working group leads and the planning committee. External review was provided by pediatric, critical care, and critical care nursing professional societies and patient partners.

RESULTS

We generated 63 Good Practice Statements and seven Grading of Recommendations Assessment, Development, and Evaluation recommendations covering 1) ethics, consent, and withdrawal of life-sustaining therapy, 2) eligibility, 3) withdrawal of life-sustaining therapy practices, 4) ante and postmortem interventions, 5) death determination, 6) neonatal pediatric donation after circulatory determination of death, 7) cardiac and innovative pediatric donation after circulatory determination of death, and 8) implementation. For brevity, 48 Good Practice Statement and truncated justification are included in this summary report. The remaining recommendations, detailed methodology, full Grading of Recommendations Assessment, Development, and Evaluation tables, and expanded justifications are available in the full text report.

CONCLUSIONS

This process showed that rigorous, transparent clinical practice guideline development is possible in the domain of pediatric deceased donation. Application of these recommendations will increase access to pediatric donation after circulatory determination of death across Canada and may serve as a model for future clinical practice guideline development in deceased donation.

Improving the Outcomes of Organs Obtained From Controlled Donation After Circulatory Death Donors Using Abdominal Normothermic Regional Perfusion

The use of donation after circulatory death (DCD) has increased significantly during the past decade. However, warm ischemia results in a greater risk for transplantation. Indeed, controlled DCD (cDCD) was associated with inferior outcomes compared with donation after brain death. The use of abdominal normothermic regional perfusion (nRP) to restore blood flow before organ recovery in cDCD has been proposed as better than rapid recovery to reverse the effect of ischemia and improve recipients' outcome. Here, the first Spanish series using abdominal nRP as an in situ conditioning method is reported. A specific methodology to avoid restoring circulation to the brain after death determination is described. Twenty-seven cDCD donors underwent abdominal nRP during at least 60 min. Thirty-seven kidneys, 11 livers, six bilateral lungs, and one pancreas were transplanted. The 1-year death-censored kidney survival was 91%, and delayed graft function rate was 27%. The 1-year liver survival rate was 90.1% with no cases of ischemic cholangiopathy. Transplanted lungs and pancreas exhibited primary function. The use of nRP may represent an advance to increase the number and quality of grafts in cDCD. Poor results in cDCD livers could be reversed with nRP. Concerns about restoring brain circulation after death are easily solved.

Decellularized Human Liver Is Too Heterogeneous for Designing a Generic Extracellular Matrix Mimic Hepatic Scaffold

Decellularized human livers are considered the perfect extracellular matrix (ECM) surrogate because both three-dimensional architecture and biological features of the hepatic microenvironment are thought to be preserved. However, donor human livers are in chronically short supply, both for transplantation or as decellularized scaffolds, and will become even scarcer as life expectancy increases. It is hence of interest to determine the structural and biochemical properties of human hepatic ECM to derive design criteria for engineering biomimetic scaffolds. The intention of this work was to obtain quantitative design specifications for fabricating scaffolds for hepatic tissue engineering using human livers as a template. To this end, hepatic samples from five patients scheduled for hepatic resection were decellularized using a protocol shown to reproducibly conserve matrix composition and microstructure in porcine livers. The decellularization outcome was evaluated through histological and quantitative image analyses to evaluate cell removal, protein, and glycosaminoglycan content per unit area. Applying the same decellularization protocol to human liver samples obtained from five different patients yielded five different outcomes. Only one liver out of five was completely decellularized, while the other four showed different levels of remaining cells and matrix. Moreover, protein and glycosaminoglycan content per unit area after decellularization were also found to be patient- (or donor-) dependent. This donor-to-donor variability of human livers thus precludes their use as templates for engineering a generic "one-size fits all" ECM-mimic hepatic scaffold.

Donation after brain circulation determination of death

Background

The fundamental determinant of death in donation after circulatory determination of death is the cessation of brain circulation and function. We therefore propose the term donation after brain circulation determination of death [DBCDD].

Results

In DBCDD, death is determined when the cessation of circulatory function is permanent but before it is irreversible, consistent with medical standards of death determination outside the context of organ donation. Safeguards to prevent error include that: 1] the possibility of auto-resuscitation has elapsed; 2] no brain circulation may resume after the determination of death; 3] complete circulatory cessation is verified; and 4] the cessation of brain function is permanent and complete. Death should be determined by the confirmation of the cessation of systemic circulation; the use of brain death tests is invalid and unnecessary.

Because this concept differs from current standards, consensus should be sought among stakeholders. The patient or surrogate should provide informed consent for organ donation by understanding the basis of the declaration of death.

Conclusion

In cases of circulatory cessation, such as occurs in DBCDD, death can be defined as the permanent cessation of brain functions, determined by the permanent cessation of brain circulation.

Ethical Issues in the Use of Extracorporeal Membrane Oxygenation in Controlled Donation After Circulatory Determination of Death

The use of donor extracorporeal membrane oxygenation (ECMO) to improve graft outcomes by some controlled donation after circulatory determination of death (cDCDD) programs raises ethical issues. We reviewed cDCDD protocols using ECMO and the relevant ethics literature to analyze these issues. It is not obvious that ECMO in cDCDD improves graft outcomes. In our opinion, ECMO implemented before death can interfere with end-of-life care and damage bodily integrity. By restoring systemic circulation, ECMO risks invalidating the preceding declaration of death if brain and cardiac perfusion is not adequately excluded because of malfunction or misplacement of the supradiaphragmatic aortic occlusion balloon. The use of ECMO is not compatible with the acronym DCDD because circulation is restored after the determination of death. Because of these deficiencies, we concluded that other techniques are preferable, such as rapid recovery or in situ cold infusion. If ECMO is performed, it requires a specific informed consent and transparency.

Can we prevent ischemic-type biliary lesions in donation after circulatory determination of death liver transplantation?

The pool of livers for transplantation consists of an increasingly greater proportion of marginal grafts, in particular those arising through donation after circulatory determination of death (DCD). However, a primary factor limiting the use of marginal livers, and, thereby, the applicability of liver transplantation in general, is concern over the subsequent development of ischemic-type biliary lesion (ITBL). ITBL is a devastating complication of liver transplantation; in its most severe forms, recipients suffer frequent infectious complications that require repeated invasive biliary procedures and ultimately result in either retransplantation or death. In the present review article, we discuss our current understanding of ITBL pathogenesis as it pertains to DCD, in particular. We discuss the most relevant theories regarding its development and provide a comprehensive overview of the most promising strategies we have available today to prevent the appearance of ITBL, strategies that may, furthermore, allow us to transplant a greater proportion of marginal livers in the future. Liver Transplantation 22 1025-1033 2016 AASLD.

An analysis of heart donation after circulatory determination of death

BACKGROUND

Heart donation after circulatory determination of death (DCDD) has provoked ethical debate focused primarily on whether heart DCDD donors are dead when death is declared and when organs are procured.

OBJECTIVE AND DESIGN

We rigorously analyse whether four heart DCDD programmes (Cape Town, Denver, Australia, Cambridge) respect the dead donor rule (DDR), according to six criteria of death: irreversible cessation of all bodily cells function (or organs), irreversible cessation of heart function, irreversible cessation of circulation, permanent cessation of circulation, irreversible cessation of brain function and permanent cessation of brain function.

CONCLUSIONS

Only death criteria based on permanency are compatible with the DDR under two conditions: (1) a minimum stand-off period of 5 min to ensure that autoresuscitation is impossible and that all brain functions have been lost and (2) no medical intervention is undertaken that might resume bodily or brain circulation. By our analysis, only the Australia heart DCDD programme using a stand-off period of 5 min respects the DDR when the criteria of death are based on permanency.

Successful Porcine Renal Transplantation After 60 Minutes of Donor Warm Ischemia: Extracorporeal Perfusion and Thrombolytics

Donation from uncontrolled circulatory determination of death donors (uDCD) is impractical in United States because of the time needed to organize procurement before irreversible organ damage. Salvaging organs after prolonged warm ischemic time (WIT) may address this limitation. We evaluated the combination of extracorporeal support (ECS) and thrombolytics in a porcine uDCD renal transplant model. Nonanticoagulated uDCD sustained 60 min of WIT, and two groups were studied. Rapid recovery (RR)-uDCD renal grafts procured using the standard quick topical cooling and renal flush, and ECS-assisted donation (E-uDCD), 4 hr ECS plus thrombolytics for in situ perfusion before procurement. All kidneys were flushed and cold stored, followed by transplantation into healthy nephrectomized recipients without immunosuppression. Delayed graft function (DGF) was defined as creatinine more than 5.0 mg/dl on any postoperative day. Twelve kidneys in E-uDCD and 6 in RR-uDCD group were transplanted. All 12 E-uDCD recipients had urine production and adequate function in the first 48 hr, but two grafts (16.7%) had DGF at 96 hr. All six recipients from RR-uDCD group had DGF at 48 hr and were killed. Creatinine and blood urea nitrogen (BUN) levels were significantly lower in E-uDCD compared with RR-uDCD group at 24 hr (2.9 ± 0.7 mg/dl vs. 5.2 ± 0.9 mg/dl) and 48 hr (3.2 ± 0.9 mg/dl vs. 7.2 ± 1.0 mg/dl); BUN levels at 24 and 48 hr were 28.3 ± 6.7 mg/dl vs. 39.5 ± 7.5 mg/dl and 23.9 ± 5.0 mg/dl vs. 46 ± 12.9 mg/dl, respectively. Thrombolytics plus ECS precondition organs in situ yielding functional kidneys in a porcine model of uDCD with 60 min of WIT. This procurement method addresses logistical limitations for uDCD use in the United States and could have a major impact on the organ donor pool.

Transplantation of kidneys from uncontrolled donation after circulatory determination of death: comparison with brain death donors with or without extended criteria and impact of normothermic regional perfusion

The aim of this study was to compare the outcomes of kidney transplants from uncontrolled DCD (uDCD) with kidney transplants from extended (ECD) and standard criteria donors (SCD). In this multicenter study, we included recipients from uDCD (n = 50), and from ECD (n = 57) and SCD (n = 102) who could be eligible for a uDCD program. We compared patient and graft survival, and kidney function between groups. To address the impact of preservation procedures in uDCD, we compared in situ cold perfusion (ICP) with normothermic regional perfusion (NRP). Patient and graft survival rates were similar between the uDCD and ECD groups, but were lower than the SCD group (P < 0.01). Although delayed graft function (DGF) was more frequent in the uDCD group (66%) than in the ECD (40%) and SCD (27%) groups (P = 0.08 and P < 0.001), graft function was comparable between the uDCD and ECD groups at 3 months onwards post-transplantation. The use of NRP in the uDCD group (n = 19) was associated with a lower risk of DGF, and with a better graft function at 2 years post-transplantation, compared to ICP-uDCD (n = 31) and ECD. In conclusion, the use of uDCD kidneys was associated with post-transplantation results comparable to those of ECD kidneys. NRP preservation may improve the results of uDCD transplantation.

The Use of Extracorporeal Circulation in Suspected Brain Dead Organ Donors with Cardiopulmonary Collapse

Donor shortage is a major limitation in organ transplantation. Several studies have reported that extracorporeal membrane oxygenation (ECMO)-assisted organ donation can be successfully completed without inducing warm ischemia in patients with brain death. The present report described clinical experience of three patients (23-yr old man, 32-yr old man, and 41-yr old woman) who underwent ECMO for the evaluation of brain death and organ donation. They donated six kidneys, three livers, and one both lungs without warm ischemia by ECMO. Six kidney recipients successfully recovered normal status without hemodialysis and two liver recipients survived with normal liver functions, but one liver recipient and one lung recipient died 3 and 15 days after transplantation. Our report strongly encourages ECMO-assisted organ donation from brain death patients with refractory cardiopulmonary collapse to achieve improved organ transplantation.

Machine perfusion in liver transplantation as a tool to prevent non-anastomotic biliary strictures: Rationale, current evidence and future directions

The high incidence of non-anastomotic biliary strictures (NAS) after transplantation of livers from extended criteria donors is currently a major barrier to widespread use of these organs. This review provides an update on the most recent advances in the understanding of the etiology of NAS. These new insights give reason to believe that machine perfusion can reduce the incidence of NAS after transplantation by providing more protective effects on the biliary tree during preservation of the donor liver. An overview is presented regarding the different endpoints that have been used for assessment of biliary injury and function before and after transplantation, emphasizing on methods used during machine perfusion. The wide spectrum of different approaches to machine perfusion is discussed, including the many different combinations of techniques, temperatures and perfusates at varying time points. In addition, the current understanding of the effect of machine perfusion in relation to biliary injury is reviewed. Finally, we explore directions for future research such as the application of (pharmacological) strategies during machine perfusion to further improve preservation. We stress the great potential of machine perfusion to possibly expand the donor pool by reducing the incidence of NAS in extended criteria organs.

Challenges in early clinical drug development for ischemia-reperfusion injury in kidney transplantation

INTRODUCTION

In an effort to expand the donor pool, kidneys from donation after cardiac death (DCD) donors are increasingly utilised in renal transplantation. These kidneys suffer greater ischemia-reperfusion injury (IRI) and have a higher incidence of delayed graft function. In the last 25 years, relatively few pharmacological therapies to reduce IRI have been tested in randomised controlled trials in renal transplantation and currently no pharmacological agents are routinely utilised for this purpose.

AREAS COVERED

The authors look at why promising treatments in pre-clinical studies have not translated to significant clinical benefit in human trials. This may reflect a translational disconnect between the pre-clinical models used and clinical problems that are encountered in the transplant population. They also discuss the issues in conducting clinical trials and its implication on drug development.

EXPERT OPINION

Translating pharmacological strategies for reducing IRI is highly challenging at every stage of development from pre-clinical studies to clinical trials. Scientific knowledge of the complexity of IRI is rapidly evolving and new treatments are expected to emerge. There are ethical barriers that prevent donor treatments, particularly in the DCD setting. However, new clinical techniques such as normothermic regional and ex-vivo perfusion represent exciting opportunities to utilise pharmacological agents earlier in the process of transplantation.

In situ normothermic regional perfusion for controlled donation after circulatory death--the United Kingdom experience

Organs recovered from donors after circulatory death (DCD) suffer warm ischemia before cold storage which may prejudice graft survival and result in a greater risk of complications after transplant. A period of normothermic regional perfusion (NRP) in the donor may reverse these effects and improve organ function. Twenty-one NRP retrievals from Maastricht category III DCD donors were performed at three UK centers. NRP was established postasystole via aortic and caval cannulation and maintained for 2 h. Blood gases and biochemistry were monitored to assess organ function. Sixty-three organs were recovered. Forty-nine patients were transplanted. The median time from asystole to NRP was 16 min (range 10-23 min). Thirty-two patients received a kidney transplant. The median cold ischemia time was 12 h 30 min (range 5 h 25 min-18 h 22 min). The median creatinine at 3 and 12 months was 107 µmol/L (range 72-222) and 121 µmol/L (range 63-157), respectively. Thirteen (40%) recipients had delayed graft function and four lost the grafts. Eleven patients received a liver transplant. The first week median peak ALT was 389 IU/L (range 58-3043). One patient had primary nonfunction. Two combined pancreas-kidney transplants, one islet transplant and three double lung transplants were performed with primary function. NRP in DCD donation facilitates organ recovery and may improve short-term outcomes.

Retrieval of the pancreas allograft for whole-organ transplantation

Proper pancreas retrieval during multi-organ recovery is one of the cornerstones of technically successful whole-organ pancreas transplantation. With evolving surgical approaches for organ retrieval and implantation, it has become standard to procure the pancreas in conjunction with other abdominal organs without compromising either vasculature, graft quality, or transplant outcomes. This review summarizes the major steps required for proper whole-organ retrieval of the pancreas allograft with suggestions and tips whenever alternative approaches are available.