How to improve the quality of kidneys from non-heart-beating donors: a randomised controlled trial of thrombolysis in non-heart-beating donors

Use of perfusion device for free flap salvage after ischemia in swine

INTRODUCTION

In free flap reconstruction, improving flap tolerance to warm ischemia (WI) is fundamental. WI is the result of a venous or arterial thrombosis, which can only be addressed through surgical revision. No additional treatments have shown superior efficacy at salvaging free flaps after or during WI. Custom perfusion machines (PM), used to reduce the intensity of lesions of the flap stored in cold ischemia, have not been evaluated for WI flap salvage. This proof-of-concept study assessed whether the Lifeport® perfusion machine could improve the salvage procedure's success rates after one hour of venous WI.

METHODS

Five different groups were evaluated with four porcine latissimus dorsi free flaps included in each group. Depending on the group, the flaps were subjected to one hour of WI followed by revascularization, static hypothermic submersion, or dynamic Lifeport® perfusion. Additionally, two flap perfusion liquids were evaluated: KPS-1® and IGL-1®. Biopsies were performed before in vivo warm ischemia of the flap, after in vivo warm ischemia of the flap, and after one and two hours of preservation. Interstitial edema, muscular cell size and muscular diffuse necrosis were quantified by histological assessment.

RESULTS

Static submersion did not demonstrate any efficacy for venous flap salvage. Dynamic perfusion on Lifeport® machine showed a significant improvement in tissue parameters. Thrombi and fibrine, present during the WI period, were no longer visible inside vessels and the perfusion machine flow evacuated the inflammatory cells and their substrates from the flap. The flap weights did not increase during perfusion time, confirming the benefits of the Lifeport® perfusion machine.

CONCLUSION

Evaluating Lifeport® advantages on human free flap salvage is necessary to confirm the benefits for the tissue and to increase post-operative results after congestive free flap revision surgery.

Salvaging donated kidneys from prolonged warm ischemia during ex vivo hypothermic oxygenated perfusion

Prolonged warm ischemic is the main cause discarding donated organs after cardiac death. Here, we identified that prolonged warm ischemic time induced disseminated intravascular coagulation and severe capillary vasospasm after cardiac death of rat kidneys. Additionally, we found a significant accumulation of fibrinogen in a hypoxic cell culture of human umbilical vein epithelial cells and in isolated kidneys exposed to prolonged warm ischemic following flushing out of blood. However, pre-flushing the kidney with snake venom plasmin in a 90-minute warm ischemic model maximized removal of micro thrombi and facilitated the delivery of oxygen and therapeutic agents. Application of carbon monoxide-releasing CORM-401 during ex vivo hypothermic oxygenated perfusion achieved multipath protective effects in prolonged warm ischemic kidneys. This led to significant improvements in perfusion parameters, restoration of the microcirculation, amelioration of mitochondrial injury, oxidative stress, and apoptosis. This benefit resulted in significantly prolonged warm ischemic kidney recipient survival rates of 70%, compared with none in those receiving ex vivo hypothermic oxygenated perfusion alone. Significantly, ex vivo hypothermic oxygenated perfusion combined with cytoprotective carbon monoxide releasing CORM-401 treatment meaningfully protected the donated kidney after cardiac death from ischemia-reperfusion injury by reducing inflammation, oxidative stress, apoptosis, and pathological damage. Thus, our study suggests a new combination treatment strategy to potentially expand the donor pool by increasing use of organs after cardiac death and salvaging prolonged warm ischemic kidneys.

The British transplantation society guidelines on organ donation from deceased donors after circulatory death

Recipient outcomes after transplantation with organs from donation after circulatory death (DCD) donors can compare favourably and even match recipient outcomes after transplantation with organs from donation after brain death donors. Success is dependent upon establishing common practices and accepted protocols that allow the safe sharing of DCD organs and maximise the use of the DCD donor pool. The British Transplantation Society 'Guideline on transplantation from deceased donors after circulatory death' has recently been updated. This manuscript summarises the relevant recommendations from chapters specifically related to organ donation.

Ex-vivo Kidney Machine Perfusion: Therapeutic Potential

Kidney transplantation remains the gold standard treatment for patients suffering from end-stage kidney disease. To meet the constantly growing organ demands grafts donated after circulatory death (DCD) or retrieved from extended criteria donors (ECD) are increasingly utilized. Not surprisingly, usage of those organs is challenging due to their susceptibility to ischemia-reperfusion injury, high immunogenicity, and demanding immune regulation after implantation. Lately, a lot of effort has been put into improvement of kidney preservation strategies. After demonstrating a definite advantage over static cold storage in reduction of delayed graft function rates in randomized-controlled clinical trials, hypothermic machine perfusion has already found its place in clinical practice of kidney transplantation. Nevertheless, an active investigation of perfusion variables, such as temperature (normothermic or subnormothermic), oxygen supply and perfusate composition, is already bringing evidence that ex-vivo machine perfusion has a potential not only to maintain kidney viability, but also serve as a platform for organ conditioning, targeted treatment and even improve its quality. Many different therapies, including pharmacological agents, gene therapy, mesenchymal stromal cells, or nanoparticles (NPs), have been successfully delivered directly to the kidney during ex-vivo machine perfusion in experimental models, making a big step toward achievement of two main goals in transplant surgery: minimization of graft ischemia-reperfusion injury and reduction of immunogenicity (or even reaching tolerance). In this comprehensive review current state of evidence regarding ex-vivo kidney machine perfusion and its capacity in kidney graft treatment is presented. Moreover, challenges in application of these novel techniques in clinical practice are discussed.

Assessing Kidney Graft Viability and Its Cells Metabolism during Machine Perfusion

Kidney transplantation is the golden treatment for end-stage renal disease. Static cold storage is currently considered the standard method of preservation, but dynamic techniques, such as machine perfusion (MP), have been shown to improve graft function, especially in kidneys donated by extended criteria donors and donation after circulatory death. With poor organ quality being a major reason for kidneys not being transplanted, an accurate, objective and reliable quality assessment during preservation could add value and support to clinicians’ decisions. MPs are emerging technologies with the potential to assess kidney graft viability and quality, both in the hypothermic and normothermic scenarios. The aim of this review is to summarize current tools for graft viability assessment using MP prior to implantation in relation to the ischemic damage.

Review of Current Machine Perfusion Therapeutics for Organ Preservation

Because of the high demand of organs, the usage of marginal grafts has increased. These marginal organs have a higher risk of developing ischemia-reperfusion injury, which can lead to posttransplant complications. Ex situ machine perfusion (MP), compared with the traditional static cold storage, may better protect these organs from ischemia-reperfusion injury. In addition, MP can also act as a platform for dynamic administration of pharmacological agents or gene therapy to further improve transplant outcomes. Numerous therapeutic agents have been studied under both hypothermic (1-8°C) and normothermic settings. Here, we review all the therapeutics used during MP in different organ systems (lung, liver, kidney, heart). The major categories of therapeutic agents include vasodilators, mesenchymal stem cells, antiinflammatory agents, antiinfection agents, siRNA, and defatting agents. Numerous animal and clinical studies have examined MP therapeutic agents, some of which have even led to the successful reconditioning of discarded grafts. More clinical studies, especially randomized controlled trials, will need to be conducted in the future to solidify these promising results and to define the role of MP therapeutic agents in solid organ transplantation.

Lysis of cold-storage-induced microvascular obstructions for ex vivo revitalization of marginal human kidneys

Thousands of kidneys from higher-risk donors are discarded annually because of the increased likelihood of complications posttransplant. Given the severe organ shortage, there is a critical need to improve utilization of these organs. To this end, normothermic machine perfusion (NMP) has emerged as a platform for ex vivo assessment and potential repair of marginal organs. In a recent study of 8 transplant-declined human kidneys on NMP, we discovered microvascular obstructions that impaired microvascular blood flow. However, the nature and physiologic impact of these lesions were unknown. Here, in a study of 39 human kidneys, we have identified that prolonged cold storage of human kidneys induces accumulation of fibrinogen within tubular epithelium. Restoration of normoxic conditions-either ex vivo during NMP or in vivo following transplant-triggered intravascular release of fibrinogen correlating with red blood cell aggregation and microvascular plugging. Combined delivery of plasminogen and tissue plasminogen activator during NMP lysed the plugs leading to a significant reduction in markers of renal injury, improvement in indicators of renal function, and improved delivery of vascular-targeted nanoparticles. Our study suggests a new mechanism of cold storage injury in marginal organs and provides a simple treatment with immediate translational potential.

A steady decline in pancreas transplantation rates

BACKGROUND/OBJECTIVES

After years of growth in many pancreas transplant programs, UNOS has reported declining transplant numbers in the USA. This precipitating trend urges for an evaluation of the transplant numbers and scientific productivity in the Eurotransplant region and the UK.

METHODS

We performed a trend analysis of pancreas transplantation rates, between 1997 and 2016, adjusting for changes in population size, and an analysis of scientific publications in this field. We used information from the UNOS, Eurotransplant, and UK transplant registry and bibliometric information from the Web of Science database.

RESULTS

Between 2004 and 2016 there was an average annual decline in pancreas transplantation rates per million inhabitants of 3.3% in the USA and 2.5% in the Eurotransplant region. In the UK, transplant numbers showed an average annual decline of 1.0% from 2009 to 2016. Publications in Q1 journals showed an annual change of -2.1% and +20.1%, before 2004, and a change of -3.8% and -5.5%, between 2004 and 2016, for USA and Eurotransplant publications, respectively.

CONCLUSIONS

Adjusting pancreas transplantation rates for changes in population size showed a clear decline in transplant numbers in both the USA and Eurotransplant region, with first signs of decline in the UK. Following this trend, the number of scientific publications in this field have declined worldwide.

The impact of alteplase on pulmonary graft function in donation after circulatory death - An experimental study

Objective

Lung transplantation is hampered by the lack of organs resulting in deaths on the waiting list. The usage of donation after circulatory death (DCD) lungs would dramatically increase donor availability. The most optimal organ preservation method, and the need for antithrombotic and fibrinolytic treatment to prevent thrombosis in the donor lungs is currently on debate. The present study investigated, in a simulated clinical DCD situation, whether the addition of alteplase in the flush-perfusion solution at the time of pulmonary graft harvesting could prevent thrombosis in the donor lung and thereby improve pulmonary graft function.

Methods

Twelve Swedish domestic pigs were randomized into two groups. All animals underwent ventricular fibrillation and were then left untouched for 1 h after declaration of death. None of the animals received heparin. The lungs were then harvested and flush-perfused with Perfadex^® solution and the organs were then stored at 8 °C for 4 h. In one group alteplase was added to the Perfadex^® solution (donation after cardiac death with alteplase (DCD-A)) and in the other, it was not (DCD). Lung function was evaluated, using ex vivo lung perfusion (EVLP), with blood gases at different oxygen levels, pulmonary vascular resistance (PVR), lung weight, and macroscopic appearance.

Results

During EVLP, there were no significant differences between groups in PaO₂ at any investigated FiO₂ level (1.0, 0.5, or 0.21). At FiO₂ 1.0, the PaO₂ in the DCD and DCD-A was 51.7 ± 2.05 kPa and 60.3 ± 3.67 kPa, respectively (p = 0.1320). There were no significant differences between groups PVR levels, in the DCD (372 ± 31 dyne x s/cm⁵) and in the DCD-A (297 ± 37 dyne x s/cm⁵) groups (p = 0.1720). There was no significant difference between groups in macroscopic appearance.

Conclusions

All the lungs showed excellent blood gases after EVLP, and they all meet the criteria's for clinical lung transplantation. The use of alteplase did not seem to have any obvious benefit to the donor lungs in a DCD situation. The donor lungs treated with alteplas showed slightly better blood gases and slightly lower PVR compared to the group without alteplas, however the difference was not significant. DCD appears to be a safe and effective method to expand the donor pool.

Thrombolytic-Enhanced Extracorporeal Cardiopulmonary Resuscitation After Prolonged Cardiac Arrest

OBJECTIVE

To investigate the effects of the combination of extracorporeal cardiopulmonary resuscitation and thrombolytic therapy on the recovery of vital organ function after prolonged cardiac arrest.

DESIGN

Laboratory investigation.

SETTING

University laboratory.

SUBJECTS

Pigs.

INTERVENTIONS

Animals underwent 30-minute untreated ventricular fibrillation cardiac arrest followed by extracorporeal cardiopulmonary resuscitation for 6 hours. Animals were allocated into two experimental groups: t-extracorporeal cardiopulmonary resuscitation (t-ECPR) group, which received streptokinase 1 million units, and control extracorporeal cardiopulmonary resuscitation (c-ECPR), which did not receive streptokinase. In both groups, the resuscitation protocol included the following physiologic targets: mean arterial pressure greater than 70 mm Hg, cerebral perfusion pressure greater than 50 mm Hg, PaO2 150 ± 50 torr (20 ± 7 kPa), PaCO2 40 ± 5 torr (5 ± 1 kPa), and core temperature 33°C ± 1°C. Defibrillation was attempted after 30 minutes of extracorporeal cardiopulmonary resuscitation.

MEASUREMENTS AND MAIN RESULTS

A cardiac resuscitability score was assessed on the basis of success of defibrillation, return of spontaneous heart beat, weanability from extracorporeal cardiopulmonary resuscitation, and left ventricular systolic function after weaning. The addition of thrombolytic to extracorporeal cardiopulmonary resuscitation significantly improved cardiac resuscitability (3.7 ± 1.6 in t-ECPR vs 1.0 ± 1.5 in c-ECPR). Arterial lactate clearance was higher in t-ECPR than in c-ECPR (40% ± 15% vs 18% ± 21%). At the end of the experiment, the intracranial pressure was significantly higher in c-ECPR than in t-ECPR. Recovery of brain electrical activity, as assessed by quantitative analysis of electroencephalogram signal, and ischemic neuronal injury on histopathologic examination did not differ between groups. Animals in t-ECPR group did not have increased bleeding complications, including intracerebral hemorrhages.

CONCLUSIONS

In a porcine model of prolonged cardiac arrest, t-ECPR improved cardiac resuscitability and reduced brain edema, without increasing bleeding complications. However, early electroencephalogram recovery and ischemic neuronal injury were not improved.

Flushing the liver with urokinase before transplantation does not prevent nonanastomotic biliary strictures

The aim of the present study was to assess whether flushing the donor liver with urokinase immediately before implantation reduces the incidence of nonanastomotic biliary strictures (NASs) after liver transplantation, without causing increased blood loss, analyzed as a historical cohort study. Between January 2005 and October 2012, all liver (re-)transplantations were included. Of the 185 liver transplant recipients included, 63 donor livers between January 2010 and October 2012 received urokinase (study group), whereas the donor liver of 122 consecutive recipients, who served as a historical control group, between January 2005 and January 2010 did not receive urokinase. Basic donor (Eurotransplant donor risk index) and recipient (age, body mass index, laboratory Model for End-Stage Liver Disease score) characteristics did not significantly differ in both groups. Thirty-three recipients developed NASs: 22 in the control group (18%) and 11 (17.5%) in the study group (P = 0.68). Analyzed separately for donation after circulatory death (P = 0.42) or donation after brain death (P = 0.89), there was no difference between the groups in incidence of NAS. Of all the recipients developing NAS, 7 (21%) needed retransplantation and all others were treated conservatively. Autologous blood transfusion requirements did not differ significantly between both groups (P = 0.91), whereas interestingly, more heterologous blood transfusions were needed in the control group (P < 0.001). This study has its limitations by its retrospective character. A multi-institutional prospective study could clarify this issue. In conclusion, arterial flushing of the liver with urokinase immediately before implantation did not lead to a lower incidence of NAS in this study, nor did it lead to increased blood loss.

Enhancing kidney function with thrombolytic therapy following donation after cardiac death: a multicenter quasi-blinded prospective randomized trial

Kidneys from donors after cardiac death (DCD) are at risk for inferior outcomes, possibly due to microthrombi and additional warm ischemia. We describe an organ procurement organization-wide trial utilizing thrombolytic tissue plasminogen activator (tPA) during machine pulsatile perfusion (MPP). A kidney from each recovered kidney pair was prospectively randomized to receive tPA (50 mg Alteplase) or no tPA (control) in the MPP perfusate. From 2011 to 2013, 24 kidneys were placed with enrolled recipients from 19 DCD kidney donors. There were no significant differences for absolute values of flow or resistance while undergoing MPP between the groups, nor rates of achieving discrete flow and resistance targets. While there was a trend toward lower creatinine and higher glomerular filtration rates in the tPA group at 3, 6, 9, and 12 months, these differences were not significant. Delayed graft function (DGF) rates were 41.7% in the tPA group vs. 58.4% in the control group (OR 0.51, 95%CI 0.10-2.59, p = 0.68). Death-censored graft survival was similar between the groups. In this pilot study, encouraging trends are seen in kidney allograft function independent of MPP parameters following DCD kidney transplantation for those kidneys receiving thrombolytic tPA and MPP, compared with standard MPP.

Recommendations for donation after circulatory death kidney transplantation in Europe

Donation after circulatory death (DCD) donors provides an invaluable source for kidneys for transplantation. Over the last decade, we have observed a substantial increase in the number of DCD kidneys, particularly within Europe. We provide an overview of risk factors associated with DCD kidney function and survival and formulate recommendations from the sixth international conference on organ donation in Paris, for best-practice guidelines. A systematic review of the literature was performed using Ovid Medline, Embase and Cochrane databases. Topics are discussed, including donor selection, organ procurement, organ preservation, recipient selection and transplant management.

Utilization of organs from donors after circulatory death for vascularized pancreas and islet of Langerhans transplantation: recommendations from an expert group

Donation after circulatory death (DCD) donors are increasingly being used as a source of pancreas allografts for vascularized organ and islet transplantation. We provide practice guidelines aiming to increase DCD pancreas utilization. We review risk assessment and donor selection criteria. We report suggested factors in donor and recipient clinical management and provide an overview of the activities and outcomes of vascularized pancreas and islet transplantation.

Ischemia/reperfusion during normothermic perfusion

INTRODUCTION

Cold storage of organs for preservation and transplantation is reaching its limits especially with extended criteria for heart beating donors and donation after cardiac death. We will discuss recent findings and perspectives in normothermic kidney preservation.

METHODS

A literature review was performed from original articles and syntheses selected by the search engine PubMed. Keywords used were: cold ischemia; warm ischemia, normothermic, organ preservation, preconditioning, organ perfusion.

RESULTS

We identified several ways to improve kidney preservation: Ischemic normothermic preconditioning; Pharmacologic normothermic preconditioning; Ex vivo normothermic reperfusion; Remote ischemic transplantation preconditioning; Ischemic postconditioning. In clinical practice, only uses of ECMO for organ preconditioning or ex vivo normothermic organ perfusion were used.

CONCLUSION

Promising experimental and clinical results make challenge cold preservation. The most suitable and physiological method seems to be a normothermic perfusion and conservation with autologous oxygenated blood using Extra Corporeal Membrane Oxygenation or Regional Normothermic Circulation.

Coagulation profiles of unexpected DCDD donors do not indicate a role for exogenous fibrinolysis

It has been suggested that vascular stasis during cardio-circulatory arrest leads to the formation of microvascular thrombi and the viability of organs arising from donation after circulatory determination of death (DCDD) donors may be improved through the application of fibrinolytic therapy. Our aim was to comprehensively study the coagulation profiles of Maastricht category II DCDD donors in order to determine the presence of coagulation abnormalities that could benefit from fibrinolytic therapy. Whole blood from potential DCDD donors suffering out-of-hospital cardiac arrest was sampled after declaration of death in the emergency department, and rotational thromboelastomeric analysis was performed. Between July 2012 and December 2013, samples from 33 potential DCDD donors were analyzed. All patients demonstrated hyperfibrinolysis (HF), as reflected by maximum clot lysis of 98-100% in all cases, indicating that there is no role for additional fibrinolytic therapy in this setting. As well, we observed correlations between thromboelastomeric lysis parameters and maximum hepatic transaminase levels measured in potential donors and renal artery flows measured during ex situ hypothermic oxygenated machine perfusion, indicating that further studies on the utility of thromboelastometry to evaluate organ injury and perhaps even viability in unexpected DCDD may be warranted.

Uncontrolled donors with controlled reperfusion after sixty minutes of asystole: a novel reliable resource for kidney transplantation

BACKGROUND

Organ shortage leads to usage of kidneys from donors after sudden cardiac death, or uncontrolled donors (UDCD). Ischemic injury due to cessation of circulation remains a crucial problem that limits adoption of UDCD. Our clinical investigation was to determine the applicability of kidneys obtained from UDCD and resuscitated by extracorporeal perfusion in situ after 60 minutes of asystole.

METHODS

In 2009-2011, organ procurement service of St. Petersburg, obtained kidneys from 22 UDCD with critically expanded warm ischemic time (WIT). No patients were considered as potential organ donors initially. All donors died after sudden irreversible cardiac arrest. Mean WIT was 61.4±4.5 minutes. For kidney resuscitation, the subnormothermic extracorporeal abdominal perfusion with thrombolytics and leukocyte depletion was employed. Grafts were transplanted into 44 recipients. The outcomes of transplantation of resuscitated kidneys were compared to outcomes of 87 KTx from 74 brain death donors (BDDs).

RESULTS

Immediate functioning of kidney grafts was observed in 21 of the 44 recipients, with no cases of primary non function. By the end of the first post-transplant year there was an acute rejection rate of 9.1% (4 episodes of rejection) in the UDCD group versus 14.2% (13 episodes of rejection) in the BDD group. The actual 1-year graft survival rate was 95.5% (n = 42) in UDCD group, and 94.6% (n = 87) in BDD group. Creatinine levels at the end of the first year were 0.116±0.008 and 0.115±0.004 mmol/l in UDCD and BDD groups, respectively.

CONCLUSIONS

UDCD kidneys with critically expanded WIT could be succefully used for transplantation if in situ organ "resuscitation" perfusion is included into procurement protocol. The results of 1-year follow-up meet the generally accepted criteria for graft survival and function. In situ reperfusion may exert a therapeutic effect on grafts before procurement. This approach could substantially expand the organ donors' pool.

The influence of perfusion solution on renal graft viability assessment

BACKGROUND

Kidneys from donors after cardiac or circulatory death are exposed to extended periods of both warm ischemia and intra-arterial cooling before organ recovery. Marshall's hypertonic citrate (HOC) and Bretschneider's histidine-tryptophan-ketoglutarate (HTK) preservation solutions are cheap, low viscosity preservation solutions used clinically for organ flushing. The aim of the present study was to evaluate the effects of these two solutions both on parameters used in clinical practice to assess organ viability prior to transplantation and histological evidence of ischemic injury after reperfusion.

METHODS

Rodent kidneys were exposed to post-mortem warm ischemia, extended intra-arterial cooling (IAC) (up to 2 h) with preservation solution and reperfusion with either Krebs-Hensleit or whole blood in a transplant model. Control kidneys were either reperfused directly after retrieval or stored in 0.9% saline. Biochemical, immunological and histological parameters were assessed using glutathione-S-transferase (GST) enzymatic assays, polymerase chain reaction and mitochondrial electron microscopy respectively. Vascular function was assessed by supplementing the Krebs-Hensleit perfusion solution with phenylephrine to stimulate smooth muscle contraction followed by acetylcholine to trigger endothelial dependent relaxation.

RESULTS

When compared with kidneys reperfused directly post mortem, 2 h of IAC significantly reduced smooth muscle contractile function, endothelial function and upregulated vascular cellular adhesion molecule type 1 (VCAM-1) independent of the preservation solution. However, GST release, vascular resistance, weight gain and histological mitochondrial injury were dependent on the preservation solution used.

CONCLUSIONS

We conclude that initial machine perfusion viability tests, including ischemic vascular resistance and GST, are dependent on the perfusion solution used during in situ cooling. HTK-perfused kidneys will be heavier, have higher GST readings and yet reduced mitochondrial ischemic injury when compared with HOC-perfused kidneys. Clinicians should be aware of this when deciding which kidneys to transplant or discard.

Ischemia-Reperfusion Injury and Ischemic-Type Biliary Lesions following Liver Transplantation

Ischemia-reperfusion (I-R) injury after liver transplantation (LT) induces intra- and/or extrahepatic nonanastomotic ischemic-type biliary lesions (ITBLs). Subsequent bile duct stricture is a significant cause of morbidity and even mortality in patients who underwent LT. Although the pathogenesis of ITBLs is multifactorial, there are three main interconnected mechanisms responsible for their formation: cold and warm I-R injury, injury induced by cytotoxic bile salts, and immunological-mediated injury. Cold and warm ischemic insult can induce direct injury to the cholangiocytes and/or damage to the arterioles of the peribiliary vascular plexus, which in turn leads to apoptosis and necrosis of the cholangiocytes. Liver grafts from suboptimal or extended-criteria donors are more susceptible to cold and warm I-R injury and develop more easily ITBLs than normal livers. This paper, focusing on liver I-R injury, reviews the risk factors and mechanisms leading to ITBLs following LT.

Liver transplantation using Donation after Cardiac Death donors

The success of solid organ transplantation has brought about burgeoning waiting lists with insufficient donation rates and substantial waiting list mortality. All countries have strived to expand donor numbers beyond the standard Donation after Brain Death (DBD). This has lead to the utilization of Donation after Cardiac Death (DCD) donors, also frequently referred to as Non-Heart Beating Donors (NHBD). Organs from these donors inevitably sustain warm ischaemic damage which varies in its extent and affects early graft function as well as graft survival. As a consequence, 'non-vital' organs such as renal transplants have increased rapidly from DCD donors but more 'vital' organ transplants such as the liver have lagged behind. However, an increasing proportion of liver transplants are now derived from DCD donors. This article covers this expansion, current results, pitfalls, and steps taken to minimize complications and to improve outcome, and future developments that are likely to occur.

Applicability and results of Maastricht type 2 donation after cardiac death liver transplantation

Maastricht type 2 donation after cardiac death (DCD) donors suffer sudden and unexpected cardiac arrest, typically outside the hospital; they have significant potential to expand the donor pool. Herein, we analyze the results of transplanted livers and all potential donors treated under our type 2 DCD protocol. Cardiac arrest was witnessed; potential donors arrived at the hospital after attempts at resuscitation had failed. Death was declared based on the absence of cardiorespiratory activity during a 5-min no-touch period. Femoral vessels were cannulated to establish normothermic extracorporeal membrane oxygenation, which was maintained until organ recovery. From April 2002 to December 2010, there were 400 potential donors; 34 liver transplants were performed (9%). Among recipients, median age, model for end-stage liver disease and cold and reperfusion warm ischemic times were 55 years (49-60), 19 (14-21) and 380 (325-430) and 30 min (26-35), respectively. Overall, 236 (59%) and 130 (32%) livers were turned down due to absolute and relative contraindications to donate, respectively. One-year recipient and graft survivals were 82% and 70%, respectively (median follow-up 24 months). The applicability of type 2 DCD liver transplant was <10%; however, with better preservation technology and expanded transplant criteria, we may be able to improve this figure significantly.

Current status and recent advances of liver transplantation from donation after cardiac death

The last decade saw increased organ donation activity from donors after cardiac death (DCD). This contributed to a significant proportion of transplant activity. Despite certain drawbacks, liver transplantation from DCD donors continues to supplement the donor pool on the backdrop of a severe organ shortage. Understanding the pathophysiology has provided the basis for modulation of DCD organs that has been proven to be effective outside liver transplantation but remains experimental in liver transplantation models. Research continues on how best to further increase the utility of DCD grafts. Most of the work has been carried out exploring the use of organ preservation using machine assisted perfusion. Both ex-situ and in-situ organ perfusion systems are tested in the liver transplantation setting with promising results. Additional techniques involved pharmacological manipulation of the donor, graft and the recipient. Ethical barriers and end-of-life care pathways are obstacles to widespread clinical application of some of the recent advances to practice. It is likely that some of the DCD offers are in fact probably “prematurely” offered without ideal donor management or even prior to brain death being established. The absolute benefits of DCD exist only if this form of donation supplements the existing deceased donor pool; hence, it is worthwhile revisiting organ donation process enabling us to identify counter remedial measures.

Derivation of the uncontrolled donation after circulatory determination of death protocol for New York city

Evidence from Europe suggests establishing out-of-hospital, uncontrolled donation after circulatory determination of death (UDCDD) protocols has potential to substantially increase organ availability. The study objective was to derive an out-of-hospital UDCDD protocol that would be acceptable to New York City (NYC) residents. Participatory action research and the SEED-SCALE process for social change guided protocol development in NYC from July 2007 to September 2010. A coalition of government officials, subject experts and communities necessary to achieve support was formed. Authorized NY State and NYC government officials and their legal representatives collaboratively investigated how the program could be implemented under current law and regulations. Community stakeholders (secular and religious organizations) were engaged in town hall style meetings. Ethnographic data (meeting minutes, field notes, quantitative surveys) were collected and posted in a collaborative internet environment. Data were analyzed using an iterative coding scheme to discern themes, theoretical constructs and a summary narrative to guide protocol development. A clinically appropriate, ethically sound UDCDD protocol for out-of-hospital settings has been derived. This program is likely to be accepted by NYC residents since the protocol was derived through partnership with government officials, subject experts and community participants.

Preservation techniques for donors after cardiac death kidneys

PURPOSE OF REVIEW

The purpose of the present review is to describe the techniques currently used to preserve kidneys from donors after cardiac death.

RECENT FINDINGS

Automated chest compression devices may be used to improve organ perfusion between cardiac death and preservation measures. Normothermic extracorporeal membrane oxygenation reduces warm ischemic injury and has the ability to improve organ viability in donors after cardiac death.

SUMMARY

Kidneys from donors after cardiac death expand the donor pool but are inevitably subjected to a period of warm ischemia. Reduction of warm ischemic injury to the organs improves transplant outcome. To reduce this injury in organs from donors after cardiac death, different preservation techniques are used. Automated chest compression devices improve organ perfusion between cardiac death and the start of organ preservation. In-situ preservation with double-balloon triple-lumen catheter is an easy technique to preserve organs in uncontrolled donors and is used in many centers to cool and flush the organs. In controlled donors, organs can also be flushed after laparotomy and direct cannulation of the aorta. Extracorporeal membrane oxygenation reduces warm ischemic injury and the use of normothermic perfusion seems promising. Optimal preservation is essential to improve the viability of kidneys from donors after cardiac death, to fully utilize this large donor pool.

Resuscitation of warm ischaemia predamaged porcine kidneys by fibrinolytic preflush with streptokinase: reduction of animal experiments

In order to reduce the number of animal experiments, the use of non-heart-beating donors (NHBDs) from a commercial abattoir has been proposed. Since the use of slaughterhouse organs is legally not defined as animal experiment, this would fulfil international standards as an alternative to animal experiments. The development of intravascular thrombosis after cardiac arrest negatively impacts organ preservation and thus viability during ischaemic storage and reperfusion. A fibrinolytic preflush with streptokinase might overcome these limitations. Therefore, the functional and histomorphological integrity of kidneys preserved immediately with intact circulation (control group A) and kidneys preserved after cardiac arrest with a 30 min period of warm ischaemia (WI) (group B) was compared with kidneys preflushed with 12.5 kU/L (group C) or 50 kU/L streptokinase (group D) after 30 min WI prior to preservation. We could demonstrate that kidneys preflushed with 12.5 kU/L streptokinase (group C) performed better than those without streptokinase pretreatment after WI (group B). Parameters like oxygen consumption, perfusion pressure, laboratory values, lactate dehydrogenase level and lipidperoxidation were closer to that of the control (group A) than in groups B and D. The higher streptokinase concentration of 50 kU/L (group D) resulted histologically in a more pronounced tissue damage and an attenuated renal function, indicating toxic effects. On the basis of our results we believe streptokinase preflushed slaughterhouse kidneys to be an adequate alternative to organs from laboratory animals with the potential to further reduce the number of animal experiments.

Use of tissue plasminogen activator in liver transplantation from donation after cardiac death donors

Ischemic-type biliary stricture (ITBS) occurs in up to 50% after liver transplantation (LT) from donation after cardiac death (DCD) donors. Thrombus formation in the peribiliary microcirculation is a postulated mechanism. The aim was to describe our experience of tissue plasminogen activator (TPA) administration in DCD-LT. TPA was injected into the donor hepatic artery on the backtable (n = 22). Two recipients developed ITBS including one graft failure. Although excessive postreperfusion bleeding was seen in 14 recipients, the amount of TPA was comparable between those with and without excessive bleeding (6.4 ± 2.8 vs. 6.6 ± 2.8 mg, p = 0.78). However, donor age (41 ± 12 vs. 29 ± 9 years, p = 0.02), donor BMI (26.3 ± 5.5 vs. 21.7 ± 3.6 kg/m(2) , p = 0.03), previous laparotomy (50% vs. 0%, p = 0.02) and lactate after portal reperfusion (6.3 ± 4.6 vs. 2.8 ± 0.9 mmol/L, p = 0.005) were significantly greater in recipients with excessive bleeding. In conclusion, the use of TPA may lower the risk of ITBS-related graft failure in DCD-LT. Excessive bleeding may be related to poor graft quality and previous laparotomy rather than the amount of TPA. Further studies are needed in larger population.

Biological modulation of liver ischemia-reperfusion injury

PURPOSE OF REVIEW

This review gives a broad overview of the key factors of ischemic injury to the liver and presents the current modifications of preservation solutions and the few strategies of biological modulation in clinical use today.

RECENT FINDINGS

Protective effects in human-liver transplantation were shown by methylprednisolone treatment in decreased donors, and by inhalation of a nontoxic dose of nitric oxide in recipients. In addition, recent results showed rescue of pig livers, donated after cardiac death by application of a cocktail of substances addressing several previously identified mechanisms of ischemia-reperfusion injury.

SUMMARY

The future of a pharmacological approach attenuating or preventing ischemia-reperfusion injury lies in a combination of drugs acting simultaneously on several steps of the injury cascades. Applying these substances during flush, before, and during implantation appears as an attractive strategy to protect extended criteria liver grafts.

Multifactorial biological modulation of warm ischemia reperfusion injury in liver transplantation from non-heart-beating donors eliminates primary nonfunction and reduces bile salt toxicity

OBJECTIVE

To design a multifactorial biological modulation approach targeting ischemia reperfusion injury to augment viability of porcine liver grafts from non-heart-beating donors (NHBD).

BACKGROUND DATA

Liver Transplantation (LTx) from NHBD is associated with an increased risk of primary nonfunction (PNF) and biliary complications. In porcine NHBD-LTx, we previously reported a 50% risk of PNF and toxic bile formation in grafts exposed to > or =30' warm ischemia (WI).

METHODS

Porcine livers exposed to 45' WI were cold stored, transplanted and either modulated (n = 6) or not (controls, n = 9). In the modulation group, donor livers were flushed with warm Ringers (avoiding cold-induced vasoconstriction), streptokinase (eliminating stagnating thrombi), and epoprostenol (vasodilator, platelet aggregation inhibitor) prior to cold storage. In recipients, glycine (Kupffer cell stabilizer), alpha1-acid-glycoprotein (anti-inflammatory protein), MAPKinase-inhibitor (pro-inflammatory cytokine generation inhibitor), alpha-tocopherol and glutathione (anti-oxidants), and apotransferrin (iron chelator) were administrated intravenously. PNF, survival, lactate, transaminase, TNF-alpha, redox-active iron, and biliary bile salt-to-phospholipid ratio were monitored.

RESULTS

No PNF was observed in modulated versus 55% in control pigs (P = 0.025). Survival was 83% in modulated versus 22% in control pigs (P = 0.02). At 180' postreperfusion, lactate was lower in modulated (5.4 +/- 1.9 mmol/L) versus control pigs (9.4 +/- 2.2 mmol/L; P = 0.011). At 60' postreperfusion, there was a trend for lower AST in modulated versus control pigs at 60' (939 +/- 578 vs. 1683 +/- 873 IU/L; P = 0.089). Postreperfusion, TNF-alpha remained stable in modulated pigs (49 +/- 27 pg/mL at 15' and 85 +/- 26 pg/mL at 180'; P = 0.399) but increased in control pigs (107 +/- 36 pg/mL at 15' and 499 +/- 216 pg/mL at 180'; P = 0.023). At 180' postreperfusion, redox-active iron was higher in control pigs versus modulated pigs (0.21+/-0.18 vs. 0.042+/-0.062 mum; P = 0.038). Biliary bile salt-to-phospholipid ratio post-LTx was lower in modulated versus control pigs (1128 +/- 447 vs. 4836 +/- 4619; P = 0.05).

CONCLUSIONS

A multifactorial biological modulation eliminates PNF, improves liver function and increases survival. Biochemically, TNF-alpha and redox-active iron are suppressed and biliary bile salt toxicity is reduced. Translating this strategy clinically may lead to wider and safer use of NHBD.

Liver transplantation: Issues for the next 20 years

The growing numbers of potential transplant recipients on waiting lists is increasingly disproportionate to the supply of cadaveric donor organs. The hope for the next 20 years is that supply will satisfy demand. This requires both a reduction in indications for the procedure and an increase in the transplants performed. A multi-pronged approach is needed to increase cadaveric organ donation, generating enthusiasm for donation among both the general public and hospital staff. Accurate assessment of marginal grafts with stringent criteria known to predict graft function will diminish wastage of organs. Methods of rehabilitating marginal grafts during extracorporeal perfusion will increase organ availability. Supply of non-heart beating donors can be greatly expanded and protocols developed with ethical consent to optimize their initial function despite warm ischemia. Splitting livers that fulfill selection criteria, thus providing for two recipients, should be universally applied with acceptable incentives to those units who do not directly benefit. A proportion of recipients, though not those transplanted for autoimmune disease, will be spared the side-effects of immunosuppression thanks to immune tolerance. Protocols for close monitoring of those patients for rejection during treatment withdrawal must be carefully observed. In addition to gene therapy, it is highly likely that hepatocyte transplantation will replace orthotopic grafting in patients without cirrhosis, especially for inherited metabolic diseases. It is much more difficult to envisage that heterologous stem cell transplantation or xenotransplantation will have clinical impact in the next 20 years, although research in those areas has obvious long-term potential.

Liver transplantation using controlled donation after cardiac death donors: an analysis of a large single-center experience

The use of donation after cardiac death (DCD) donors may provide a valuable source of organs for liver transplantation. Concerns regarding primary nonfunction (PNF) and intrahepatic biliary stricture (IHBSs) have limited the enthusiasm for their use. A retrospective analysis of 1436 consecutive deceased donor liver transplants performed between December 1998 and October 2006 was conducted. These included 108 DCD liver transplants, which were compared to 1328 transplants performed with organs from donors meeting the criteria for donation after brain death (DBD). The median follow-up was 48 months. The 1-, 3-, and 5-year patient survival and graft survival for DCD donors were 91.5%, 88.1%, and 88.1% and 79.3%, 74.5%, and 71.0%, respectively. The 1-, 3-, and 5-year patient survival and graft survival for DBD donors were 87.3%, 81.1%, and 77.2% and 81.6%, 74.7%, and 69.1%, respectively. Patient survival and graft survival were not significantly different between DCD donors less than 60 years old, DCD donors greater than 60 years old, and DBD donors. Causes of graft loss included IHBSs (n = 9), PNF (n = 4), recurrent hepatitis C virus (n = 4), hepatic artery thrombosis (n = 1), rejection (n = 2), and patient death (n = 13). Contrary to previously published data, excellent long-term patient survival and graft survival can be obtained with DCD allografts, and in our experience, they are equivalent to those obtained from DBD allografts.

Peritoneal cooling may provide improved protection for uncontrolled donors after cardiac death: an exploratory porcine study

Uncontrolled donation after cardiac death (DCD) renal transplantation relies on rapid establishment of organ preservation interventions. We have developed a model of the uncontrolled DCD, comparing current in situ perfusion (ISP) techniques with additional peritoneal cooling (PC). Ten pigs were killed and subjected to a 2 h ischemia period. The ISP group modeled current DCD protocols. The PC group (PC) modeled current protocols plus PC. Two animals were used as controls and subjected to 2 h of warm ischemia. Core renal temperature and microdialysis markers of ischemia were measured. Preservation interventions began at 30 min, with rapid laparotomy and kidney recovery performed at 2 h, prior to machine perfusion viability testing. The final mean renal temperature achieved in the ISP group was 26.3 degrees C versus 16.9 degrees C in the PC group (p = 0.0001). A significant cryopreservation benefit was suggested by lower peak microdialysate lactate and glycerol levels (ISP vs. PC, p = 0.0003 and 0.0008), and the superiority of the PC group viability criteria (p = 0.0147). This pilot study has demonstrated significant temperature, ischemia protection and viability assessment benefits with the use of supplementary PC. The data suggests a need for further research to determine the potential for reductions in the rates of ischemia-related clinical phenomena for uncontrolled DCDs.

Intragraft coagulation events and delayed graft function in clinical renal transplantation

BACKGROUND

Cold preservation, reperfusion damage, immunosuppressive drugs, and uremia-induced acquired thrombophilias increase the risk of thrombotic complications in renal transplantation. Intragraft fibrin deposition may be associated with delayed graft function.

METHODS

We studied coagulation and fibrinolysis in 45 patients of a larger trial in renal transplantation: perioperative antithymocyte globulin (group A, n=15), perioperative basiliximab (group B, n=16), and conventional triple therapy (group C, n=14). Blood samples for prothrombin fragment F1+2, plasminogen activator inhibitor (PAI)-1, d-dimer, tPA antigen, tPA activity, and platelet counts were obtained simultaneously at 1 and 5 min after reperfusion from iliac artery and graft vein for calculation of transrenal changes. Because antithymocyte globulin activates coagulation and fibrinolysis, group A was analyzed separately. Groups B and C were pooled (group BC).

RESULTS

In group BC, transrenal D-dimer release occurred at 1 min, tPA-antigen release at 1 and 5 min, and transrenal PAI-1 uptake at 5 min postreperfusion. tPA activity increased marginally only at 1 min. High graft tPA-antigen release at 5 min and D-dimer release at 1 min were associated with delayed graft function. In group A, transrenal tPA-antigen release occurred at 1 and 5 min and D-dimer release at 1 min. There were no transrenal F1+2 changes in either group.

CONCLUSION

Although graft PAI-1 uptake inhibits tPA activity, graft releases D-dimer at early reperfusion without concomitant F1+2 release. Data suggest thrombin and fibrin formation already before cold preservation during donor care and organ retrieval. This fibrin deposition increases risk of delayed graft function.

Non heart-beating donors in England

When transplantation started all organs were retrieved from patients immediately after cardio-respiratory arrest, i.e. from non heart-beating donors. After the recognition that death resulted from irreversible damage to the brainstem, organ retrieval rapidly switched to patients certified dead after brainstem testing. These heart-beating-donors have become the principal source of organs for transplantation for the last 30 years. The number of heart-beating-donors are declining and this is likely to continue, therefore cadaveric organs from non-heart-beating donor offers a large potential of resources for organ transplantation. The aim of this study is to examine clinical outcomes of non-heart-beating donors in the past 10 years in the UK as an way of decreasing pressure in the huge waiting list for organs transplantation.

Ischemic cholangiopathy after liver transplantation from controlled non-heart-beating donors-a single-center experience

BACKGROUND

Previous reports have shown that livers from controlled non-heart-beating-donors (NHBD) are associated with higher rates of primary failure and ischemic cholangiopathy of orthotopic liver transplantation (OLT) as a complication of the prolonged warm ischemia.

METHODS

This retrospective review of activities from 1999 to 2006 examined donor characteristics of age, liver function tests, warm ischemic time before (1WITa) and after cardiac arrest (1WITb), cold ischemic time (CIT) and transplant results.

RESULTS

Eleven NHBD retrieved livers were transplanted from "ideal" donors except for one elderly donor (73 years). Of the 11 recipients, 3 developed biliary cholangiopathy (27%). There were no episodes of primary graft nonfunction, but one recipient displayed primary graft dysfunction. Two recipients died: one due to biliary complications with sepsis (long CIT >10 hours, fatty liver), and the other due to aspiration pneumonia and hypoxic brain damage with normal liver function. One recipient required retransplantation owing to ischemic cholangiopathy (1WITb 45 min) at 6 months after OLT with a good result. The other eight recipients are alive (observation period 72 to 14 months) including six with normal liver function, one with biopsy-proven biliary ischemia and one with recurrent primary sclerosing cholangitis without biliary ischemic changes on biopsy. Among 164 heart-beating donors recipients transplanted in the same period, biliary complications occurred in 27 patients (16%), of whom 12 were leaks and 15 anastomotic strictures.

CONCLUSION

NHBD were a good source for livers with reasonable early results. To avoid late complications especially ischemic cholangiopathy, caution is urged with the use of these organs as well as strict donor and ischemic time criteria.

In situ preservation of kidneys from donors after cardiac death: results and complications

OBJECTIVES

To describe the results and complications of in situ preservation (ISP) of kidneys from donors after cardiac death (DCD).

BACKGROUND

DCD donors are increasingly being used to expand the pool of donor kidneys. ISP reduces warm ischemic injury which is associated with DCD donation.

METHODS

Insertion of a double-balloon triple-lumen catheter allows selective perfusion of the abdominal aorta to preserve the kidneys in situ. From January 2001 until August 2005, 133 ISP procedures were initiated in our procurement area.

RESULTS

Fifty-six (42%) ISP procedures led to transplantation; in the remaining 77 cases (58%), the donation procedure was abandoned or both kidneys were discarded because of ISP complications (n = 31), poor graft quality (n = 23), no consent for donation (n = 13), medical contraindications (n = 8), or unknown cause (n = 2). Increasing donor age (odds ratio (OR) 1.06 per year, P < 0.001) and uncontrolled DCD donation (OR 5.4, P < 0.001) were independently correlated with ISP complications. After transplantation, prolonged double-balloon triple-lumen catheter insertion time was an independent predictor of graft failure (OR 2.0, P = 0.05). Selected controlled DCD donors were managed by rapid laparotomy and direct aortic cannulation; graft survival of these kidneys was superior to kidneys from controlled DCD donors managed by ISP.

CONCLUSIONS

A minority of initiated ISP procedures led to transplantation, resulting in a high workload compared with donation after brain death. The association between increasing catheter insertion time and inferior graft outcome emphasizes the need for fast and effective surgery. Therefore, rapid laparotomy with direct aortic cannulation is preferred over ISP in controlled DCD donation. Despite these limitations, we have expanded our donor pool 3- to 4-fold by procuring DCD kidneys that were preserved in situ.

In defense of the reverence of all life: Heideggerean dissolution of the ethical challenges of organ donation after circulatory determination of death

During the past 50 years since the first successful organ transplant, waiting lists of potential organ recipients have expanded exponentially as supply and demand have been on a collision course. The recovery of organs from patients with circulatory determination of death is one of several effective alternative approaches recommended to reduce the supply-and-demand gap. However, renewed debate ensues regarding the ethical management of the overarching risks, pressures, challenges and conflicts of interest inherent in organ retrieval after circulatory determination of death. In this article, the author claims that through the engagement of a Heideggerean existential phenomenological and hermeneutic framework what are perceived as ethical problems dissolve, including collapse of commitment to the dead donor rule. The author argues for a revisioned socially constructed conceptual and philosophical responsibility of humankind to recognize the limits of bodily finitude, to responsibly use the capacity of the transplantable organs, and to grant enhanced or renewed existence to one with diminished or life-limited capacity; thereby making the locus of ethical concern the donor-recipient as unitary ''life.'' What ethically matters in the life-cycle (life-world) of donor-recipient is the viability of the organs transplanted; thereby granting reverence to all life.