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

Indocyanine green fluorescence quantification during normothermic ex situ perfusion for the assessment of porcine liver grafts after circulatory death

Current graft evaluation during normothermic ex situ liver perfusion lacks real-time parameters for predicting posttransplant hepatocyte and biliary function. Indocyanine green (ICG) imaging has been widely used in liver surgery, enabling the visualization of hepatic uptake and excretion through bile using near-infrared light. In this research, porcine livers under various ischemic conditions were examined during a 5-hour normothermic ex situ liver perfusion procedure, introducing ICG at 1 hour through the hepatic artery. These conditions included livers from heart-beating donors, donation after circulatory death (DCD) with warm ischemic durations of 60 minutes (DCD60) and 120 minutes (DCD120), as well as interventions utilizing tissue plasminogen activator in DCD120 cases (each n = 5). Distinct hepatic fluorescence patterns correlated with different degrees of ischemic injury ( p = 0.01). Low ICG uptake in the parenchyma (less than 40% of maximum intensity) was more prevalent in DCD120 (21.4%) compared to heart-beating donors (6.2%, p = 0.06) and DCD60 (3.0%, p = 0.02). Moreover, ICG clearance from 60 minutes to 240 minutes was significantly higher in heart-beating donors (69.3%) than in DCD60 (17.5%, p < 0.001) and DCD120 (32.1%, p = 0.01). Furthermore, thrombolytic intervention using tissue plasminogen activator in DCD120 resulted in noteworthy outcomes, including significantly reduced ALP levels ( p = 0.04) and improved ICG clearance ( p = 0.02) with a trend toward mitigating fibrin deposition similar to DCD60, as well as enhancements in bile production ( p = 0.09). In conclusion, ICG fluorescence imaging during normothermic ex situ liver perfusion provides real-time classification of hepatic vascular and biliary injuries, offering valuable insights for the more accurate selection and postintervention evaluation of marginal livers in transplantation.

Better liver transplant outcomes by donor interventions?

PURPOSE OF REVIEW

Donor risk factors and events surrounding donation impact the quantity and quality of grafts generated to meet liver transplant waitlist demands. Donor interventions represent an opportunity to mitigate injury and risk factors within donors themselves. The purpose of this review is to describe issues to address among donation after brain death, donation after circulatory determination of death, and living donors directly, for the sake of optimizing relevant outcomes among donors and recipients.

RECENT FINDINGS

Studies on donor management practices and high-level evidence supporting specific interventions are scarce. Nonetheless, for donation after brain death (DBD), critical care principles are employed to correct cardiocirculatory compromise, impaired tissue oxygenation and perfusion, and neurohormonal deficits. As well, certain treatments as well as marginally prolonging duration of brain death among otherwise stable donors may help improve posttransplant outcomes. In donation after circulatory determination of death (DCD), interventions are performed to limit warm ischemia and reverse its adverse effects. Finally, dietary and exercise programs have improved donation outcomes for both standard as well as overweight living donor (LD) candidates, while minimally invasive surgical techniques may offer improved outcomes among LD themselves.

SUMMARY

Donor interventions represent means to improve liver transplant yield and outcomes of liver donors and grafts.

Bile Chemistry During Ex Situ Normothermic Liver Perfusion Does Not Always Predict Cholangiopathy

BACKGROUND

Bile chemistry during normothermic ex situ liver perfusion (NESLiP) has been suggested to be an indicator of cholangiopathy. The normal range of biochemical variables in bile of livers undergoing NESLiP has not been defined, nor have published biliary viability criteria been assessed against instances of posttransplant nonanastomotic bile strictures (NASs).

METHODS

The bile and perfusate chemistry of 200 livers undergoing NESLiP between February 1, 2018, and October 30, 2023, was compared. In addition, 11 livers that underwent NESLiP and later developed NAS were selected and their bile chemistry was also examined.

RESULTS

In livers that did not develop cholangiopathy, concentrations of sodium, potassium, and chloride were slightly higher in bile than in perfusate, whereas the concentration of calcium was slightly lower. Bile was alkali and had a lower glucose concentration than perfusate. Cholangiocyte glucose reabsorption was shown to saturate at high perfusate concentrations and was more impaired in livers donated after circulatory death than in livers donated after brain death. Published criteria failed to identify all livers that went on to develop NASs.

CONCLUSIONS

A significant false-negative rate exists with current biliary viability criteria, probably reflecting the patchy and incomplete nature of the development of NASs in the biliary tree. The data presented here provide a benchmark for future assessment of bile duct chemistry during NESLiP.

Current Techniques and Indications for Machine Perfusion and Regional Perfusion in Deceased Donor Liver Transplantation

Since the advent of University of Wisconsin preservation solution in the 1980s, clinicians have learned to work within its confines. While affording improved outcomes, considerable limitations still exist and contribute to the large number of livers that go unused each year, often for fear they may never work. The last 10 years have seen the widespread availability of new perfusion modalities which provide an opportunity for assessing organ viability and prolonged organ storage. This review will discuss the role of in situ normothermic regional perfusion for livers donated after circulatory death. It will also describe the different modalities of ex situ perfusion, both normothermic and hypothermic, and discuss how they are thought to work and the opportunities afforded by them.

Modern-Day Practice of DCD Liver Transplantation: Controversies, Innovations, and Future Directions

PURPOSE OF REVIEW

Over the past decade, donation after circulatory death (DCD) liver transplantation has expanded in the United States due to improved surgical experience and perioperative management. Despite these advances, there remains a reluctance towards broader utilization of DCD liver allografts due to lack of standardized donation process, concern for inferior graft survival, and risk of ischemic cholangiopathy associated with temporary lack of oxygenated perfusion during withdrawal of life-supporting treatment during procurement.

RECENT FINDINGS

New perfusion technologies offer potential therapeutic options to mitigate biliary complications and expand utilization of marginal DCD grafts. As these modalities enter routine clinical practice, DCD utilization will continue to increase, and liver allocation policies in turn will evolve to reflect this growing practice. This review describes recent progress in DCD LT, current challenges with utilization of DCD liver allografts, and how novel technologies and policies could impact the future of the field.

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.

D-dimer Release From Livers During Ex Situ Normothermic Perfusion and After In Situ Normothermic Regional Perfusion: Evidence for Occult Fibrin Burden Associated With Adverse Transplant Outcomes and Cholangiopathy

BACKGROUND

Deceased donor livers are prone to biliary complications, which may necessitate retransplantation, and we, and others, have suggested that these complications are because of peribiliary vascular fibrin microthrombi. We sought to determine the prevalence and consequence of occult fibrin within deceased donor livers undergoing normothermic ex situ perfusion (NESLiP) and evaluate a role for fibrinolysis.

METHODS

D-dimer concentrations, products of fibrin degradation, were assayed in the perfusate of 163 livers taken after 2 h of NESLiP, including 91 that were transplanted. These were related to posttransplant outcomes. Five different fibrinolytic protocols during NESLiP using alteplase were evaluated, and the transplant outcomes of these alteplase-treated livers were reviewed.

RESULTS

Perfusate D-dimer concentrations were lowest in livers recovered using in situ normothermic regional perfusion and highest in alteplase-treated livers. D-dimer release from donation after brain death livers was significantly correlated with the duration of cold ischemia. In non-alteplase-treated livers, Cox proportional hazards regression analysis showed that D-dimer levels were associated with transplant survival ( P  = 0.005). Treatment with alteplase and fresh frozen plasma during NESLiP was associated with significantly more D-dimer release into the perfusate and was not associated with excess bleeding postimplantation; 8 of the 9 treated livers were free of cholangiopathy, whereas the ninth had a proximal duct stricture.

CONCLUSIONS

Fibrin is present in many livers during cold storage and is associated with poor posttransplant outcomes. The amount of D-dimer released after fibrinolytic treatment indicates a significant occult fibrin burden and suggests that fibrinolytic therapy during NESLiP may be a promising therapeutic intervention.

Risk factors and management of hepatic artery stenosis post liver transplantation

BACKGROUND

Hepatic Artery Stenosis (HAS) after liver transplantation (LT), if untreated, can lead to hepatic artery thrombosis (HAT) that carries significant morbidity.

AIMS

To identify risk factors associated with HAS and determine if endovascular therapy (EVT) reduces the occurrence of HAT.

METHODS

This is a retrospective cohort study of adult LT patients between 2013 and 2018. The primary outcome was development of HAT, and secondary outcomes included graft failure and mortality. Logistic regression was used to ascertain the odds ratio of developing HAS. Outcomes between intervention types were compared with Fisher's-exact test.

RESULTS

The odds of HAS doubled in DCD-donor recipients (OR=2.27; P = 0.04) and transplants requiring vascular reconstruction for donor arterial variation (OR=2.19, P = 0.046). Of the 63 identified HAS patients, 44 underwent EVT, 7 with angioplasty alone, 37 combined with stenting. HAT was not significantly different in those who underwent angioplasty with or without stenting than conservative treatment (P = 0.71). However, compared to patients without HAS, patients with HAS had higher odds of biliary stricture and decreased graft and overall patient survival (log-rank P < 0.001 & P = 0.019, respectively).

CONCLUSION

HAS is significantly higher in DCD-graft recipients. EVT was not associated with reduction in HAT progression. HAS has poor graft and overall survival.

Antemortem Heparin in Organ Donation After Circulatory Death Determination: A Systematic Review of the Literature

Donation after circulatory death determination frequently involves antemortem heparin administration to mitigate peri-arrest microvascular thrombosis. We systematically reviewed the literature to: (1) describe heparin administration practices and (2) explore the effects on transplant outcomes. We searched MEDLINE and EMBASE for studies reporting donation after circulatory death determination heparin practices including use, dosage, and timing (objective 1). To explore associations between antemortem heparin and transplant outcomes (objective 2), we (1) summarized within-study comparisons and (2) used meta-regression analyses to examine associations between proportions of donors that received heparin and transplant outcomes. We assessed risk of bias using the Newcastle Ottawa Scale and applied the GRADE methodology to determine certainty in the evidence. For objective 1, among 55 eligible studies, 48 reported heparin administration to at least some donors (range: 15.8%-100%) at variable doses (up to 1000 units/kg) and times relative to withdrawal of life-sustaining therapy. For objective 2, 7 studies that directly compared liver transplants with and without antemortem heparin reported lower rates of primary nonfunction, hepatic artery thrombosis, graft failure at 5 y, or recipient mortality (low certainty of evidence). In contrast, meta-regression analysis of 32 liver transplant studies detected no associations between the proportion of donors that received heparin and rates of early allograft dysfunction, primary nonfunction, hepatic artery thrombosis, biliary ischemia, graft failure, retransplantation, or patient survival (very low certainty of evidence). In conclusion, antemortem heparin practices vary substantially with an uncertain effect on transplant outcomes. Given the controversies surrounding antemortem heparin, clinical trials may be warranted.

Thromboelastography profiles for controlled circulatory death donors: Validating the role of heparin

Controlled donation after circulatory death (cDCD) liver transplants are associated with increased ischemic-type biliary complications. Microvascular thrombosis secondary to decreased donor fibrinolysis may contribute to bile duct injury. We hypothesized that cDCD donors are hypercoagulable with impaired fibrinolysis and aim to use thromboelastography to characterize cDCD coagulation profiles.

Regulations and Procurement Surgery in DCD Liver Transplantation: Expert Consensus Guidance From the International Liver Transplantation Society

Donation after circulatory death (DCD) donors are an increasingly more common source of livers for transplantation in many parts of the world. Events that occur during DCD liver recovery have a significant impact on the success of subsequent transplantation. This working group of the International Liver Transplantation Society evaluated current evidence as well as combined experience and created this guidance on DCD liver procurement. Best practices for the recovery and transplantation of livers arising through DCD after euthanasia and organ procurement with super-rapid cold preservation and recovery as well as postmortem normothermic regional perfusion are described, as are the use of adjuncts during DCD liver procurement.

Early Allograft Dysfunction After Liver Transplantation With Donation After Circulatory Death and Brain Death Grafts: Does the Donor Type Matter?

Background.

Early allograft dysfunction (EAD) after liver transplantation has been associated with long-term reduced graft and patient survival.

Methods.

In this single-center cohort study, we aimed to compare incidence, risk factors, and outcomes in liver transplant recipients who developed EAD. Patients who received donation after circulatory death (DCD) or donation after brain death (DBD) grafts between January 2007 and December 2017 were included. EAD was defined as bilirubin of ≥10 mg/dL (171 μmol/L) or an international normalized ratio of ≥1.6 on postoperative day 7 or transaminases >2000 U\L in the first-week posttransplantation as previously described.

Results.

In our cohort of 1068 patients, incidence of EAD was 44%. EAD occurred more frequently in the DCD versus DBD group (71% versus 41%, P < 0.01). Overall, recipients who developed EAD showed a significantly lower graft and patient survival at 1, 3, and 5 y after transplantation (all P < 0.05). This was also the case for recipients of DBD grafts. However, for recipients of DCD grafts, patient and graft survival were not affected by the presence of EAD. For recipients of DBD grafts, donor age, body mass index (BMI) and gender, recipient BMI and model for end-stage liver disease score and warm and cold ischemia time were associated with EAD. For DCD recipients, donor BMI and cold ischemia time were associated with EAD.

Conclusions.

In our cohort study, EAD resulted in reduced long-term patient and graft survival only for DBD recipients but not for DCD recipients. Predictive markers for EAD were dependent on the donor type.

Thrombolytic Therapy During ex-vivo Normothermic Machine Perfusion of Human Livers Reduces Peribiliary Vascular Plexus Injury

Background: A major limitation in expanding the use of donation after circulatory death (DCD) livers in transplantation is the increased risk of graft failure secondary to ischemic cholangiopathy. Warm ischemia causes thrombosis and injury to the peribiliary vascular plexus (PVP), which is supplied by branches of the hepatic artery, causing higher rates of biliary complications in DCD allografts.

Aims/Objectives: We aimed to recondition discarded DCD livers with tissue plasminogen activator (tPA) while on normothermic machine perfusion (NMP) to improve PVP blood flow and reduce biliary injury.

Methods: Five discarded DCD human livers underwent 12 h of NMP. Plasminogen was circulated in the base perfusate prior to initiation of perfusion and 1 mg/kg of tPA was administered through the hepatic artery at T = 0.5 h. Two livers were split prior to perfusion (S1, S2), with tPA administered in one lobe, while the other served as a control. The remaining three whole livers (W1-W3) were compared to seven DCD control liver perfusions (C1-C7) with similar hepatocellular and biliary viability criteria. D-dimer levels were measured at T = 1 h to verify efficacy of tPA. Lactate, total bile production, bile pH, and difference in biliary injury scores before and after perfusion were compared between tPA and non-tPA groups using unpaired, Mann-Whitney tests.

Results: Average weight-adjusted D-dimer levels were higher in tPA livers in the split and whole-liver model, verifying drug function. There were no differences in perfusion hepatic artery resistance, portal vein resistance, and arterial lactate between tPA livers and non-tPA livers in both the split and whole-liver model. However, when comparing biliary injury between hepatocellular and biliary non-viable whole livers, tPA livers had significantly lower PVP injury scores (0.67 vs. 2.0) and mural stroma (MS) injury scores (1.3 vs. 2.7).

Conclusion: This study demonstrates that administration of tPA into DCD livers during NMP can reduce PVP and MS injury. Further studies are necessary to assess the effect of tPA administration on long term biliary complications.

Donation after circulatory death liver transplantation: An in-depth analysis and propensity score-matched comparison

BACKGROUND

Careful donor-recipient matching and reduced ischemia times have improved outcomes following donation after circulatory death (DCD) liver transplantation (LT). This study examines a single-center experience with DCD LT including high-acuity and hospitalized recipients.

METHODS

DCD LT outcomes were compared to a propensity score-matched (PSM) donation after brain death (DBD) LT cohort (1:4); 32 DCD LT patients and 128 PSM DBD LT patients transplanted from 2008 to 2018 were included. Analyses included Kaplan-Meier estimates and Cox proportional hazards models examining patient and graft survival.

RESULTS

Median MELD score in the DCD LT cohort was 22, with median MELD of 27 for DCD LT recipients with decompensated cirrhosis. No difference in mortality or graft loss was found (p < .05) between DCD LT and PSM DBD LT at 3 years post-transplant, nor was DCD an independent risk factor for patient or graft survival. Post-LT severe acute kidney injury was similar in both groups. Ischemic-type biliary lesions (ITBL) occurred in 6.3% (n = 2) of DCD LT recipients, resulting in 1 graft loss and 1 death.

CONCLUSION

This study supports that DCD LT outcomes can be similar to DBD LT, with a low rate of ITBL, in a cohort including high-acuity recipients. Strict donor selection criteria, ischemia time minimization, and avoiding futile donor/recipient combinations are essential considerations.

Evolving utilization of donation after circulatory death livers in liver transplantation: The day of DCD has come

Compared to donation after brain death (DBD), livers procured for transplantation from donation after circulatory death (DCD) donors experience more ischemia-reperfusion injury and higher rates of ischemic cholangiopathy due to the period of warm ischemic time (WIT) following withdrawal of life support. As a result, utilization of DCD livers for liver transplant (LT) has generally been limited to short WITs and younger aged donor grafts, causing many recovered DCD organs to be discarded without consideration for transplant. This study assesses how DCD liver utilization and outcomes have changed over time, using OPTN data from adult, first-time, deceased donor, whole-organ LTs between January 1995 and December 2019. Results show that increased clinical experience with DCD LT has translated into increased use of livers from DCD donors, shorter ischemic times, shorter lengths of hospitalization after transplant, and lower rates of retransplantation. The data also reveal that over the past decade, the rate of increase in DCD LTs conducted in the United States has outpaced that of DBD. Together, these trends signal an opportunity for the field of liver transplantation to mitigate the organ shortage by capitalizing on DCD liver allografts that are currently not being utilized.

Liver Transplantation in a Patient With Acute-on-Chronic Liver Failure Due to Traditional Chinese Medicine Intoxication Using Donation After Circulatory Death From a Renal Transplant Recipient: A Case Report

Acute-on-chronic liver failure (ACLF) is a clinical manifestation of acute liver failure and decompensation on the basis of chronic liver disease. To date, hepatitis B virus-related ACLF is still the main cause of liver failure in China. Liver transplantation is currently the most likely treatment option to cure ACLF, but the shortage of donor livers is a barrier to its widespread use. The shortage of organs has led to increased use of expanded-criteria donors (ECDs), that is, donation after cardiac death (DCD) and its variant donation after brain and cardiac death (DBCD-China, DCBD-Switzerland). Here we report a case of liver transplantation, whose recipient was diagnosed with ACLF as a result of use of traditional Chinese medicine while the donor liver was retrieved from a renal transplant patient 4 years after transplantation. This transplant was carried out in accordance with the Helsinki Congress and the Declaration of Istanbul.

Detection of early allograft dysfunction at 30 min of reperfusion in liver transplantation: An intraoperative diagnostic tool with real time assessment of graft function

INTRODUCTION

During the anhepatic phase of liver transplantation (LT), fibrinolytic activity increases, since the liver clears tissue plasminogen activator (tPA). We hypothesize that patients who fail to reduce fibrinolytic activity following graft reperfusion will have an increased rate of early allograft dysfunction (EAD).

METHODS

Assessment of fibrinolysis in liver transplant recipients was quantified with thrombelastography (TEG) LY30. Changes in LY30 were assessed after graft reperfusion. The 30-min post-reperfusion LY30 was subtracted from the anhepatic LY30 quantifying fibrinolytic changes (delta-LY30).

RESULTS

Seventy-three primary LT patients were included in the analysis. Receiver operating characteristic curve (ROC) analysis identified an inflection point of delta-LY30-5.3% as a risk factor for EAD. EAD occurred in 44% of these patients compared to 5% in high delta-LY30 (p = 0.002).

CONCLUSION

LT recipients that develop hyperfibrinolysis who fail to reduce fibrinolytic activity 30 min after graft reperfusion had an EAD rate 8-fold higher than patients who had a large reduction in LY30 following reperfusion.

A Share 21 model in liver transplantation: Impact on waitlist outcomes

With the introduction of Model for End-Stage Liver Disease-Sodium (MELD-Na)-based allocation, the score at which patients benefit from liver transplantation (LT) has shifted from a score of 15 to 21. This study aimed to evaluate waitlist outcomes in patients with MELD-Na scores <21 and explore the utility of replacing "Share 15" with "Share 21." The study uses data from the Organ Procurement and Transplantation Network/United Network for Organ Sharing registry. All adult patients registered for LT after implementation of the MELD-Na-based allocation were evaluated. Waitlist patients with initial and final scores <21 were eligible. Patients with exception scores were excluded. To explore the potential impact of a Share 21 model, patients with an initial MELD-Na score of 6-14 (Group 1) and those with a score of 15-20 (Group 2) were compared for waitlist outcomes. There were 3686 patients with an initial score of 6-14 (Group 1) and 3282 with a score of 15-20 (Group 2). Group 2, when compared to Group 1, showed comparable risk of mortality (adjusted hazard ratio [aHR] 1.00, P = .97), higher transplant probability (aHR 3.25, P < .001), and lower likelihood of removal from listing because of improvement (aHR 0.74, P = .011). Share 21 may enhance transplant opportunities and increase parity for patients with higher MELD-Na scores without compromising waitlist outcomes.

Donation after Circulatory Death: Potential Mechanisms of Injury and Preventative Strategies

Donation after circulatory death (DCD) donors represent a potential means to help address the disparity between the number of patients awaiting liver transplantation (LT) and the availability of donor livers. While initial enthusiasm for DCD LT was high in the early 2000s, early reports of high rates of biliary complications and inferior graft survival resulted in reluctance among many transplant centers to use DCD liver grafts. As with all innovations in transplant practice, there is undoubtedly a learning curve associated with the optimal utilization of liver grafts from DCD donors. More contemporary data has demonstrated that results with DCD LT are improving and the number of DCD LT performed annually has been steadily increasing. In this concise review, potential mechanisms of injury for DCD livers are discussed along with strategies that have been employed in clinical practice to improve DCD LT outcomes.

Donation after circulatory death liver transplantation: consensus statements from the Spanish Liver Transplantation Society

Livers from donation after circulatory death (DCD) donors are an increasingly more common source of organs for transplantation. While there are few high-level studies in the field of DCD liver transplantation, clinical practice has undergone progressive changes during the past decade, in particular due to mounting use of postmortem normothermic regional perfusion (NRP). In Spain, uncontrolled DCD has been performed since the late 1980s/early 1990s, while controlled DCD was implemented nationally in 2012. Since 2012, the rise in DCD liver transplant activity in Spain has been considerable, and the great majority of DCD livers transplanted in Spain today are recovered with NRP. A panel of the Spanish Liver Transplantation Society was convened in 2018 to evaluate current evidence and accumulated experience in DCD liver transplantation, in particular addressing issues related to DCD liver evaluation, acceptance criteria, and recovery as well as recipient selection and postoperative management. This panel has created a series of consensus statements for the standard of practice in Spain and has published these statements with the hope they might help guide other groups interested in implementing new forms of DCD liver transplantation and/or introducing NRP into their clinical practices.

Liver graft from donation after circulatory death donor: Real practice to improve graft viability

Donation after circulatory death (DCD) is an increasing source of liver grafts for transplantation, yet outcomes have been inferior compared to donation after brain death liver transplantation. These worse outcomes are mainly due to the severe graft injury resulting from mandatory warm ischemia during DCD organ recovery. New evidence, however, indicates that improved donor selection and surgical techniques can decrease the risk of graft failure and ischemic cholangiopathy (IC). Under current best practices, DCD organs are retrieved with the super-rapid technique, optimizing timing and protecting the liver graft from detrimental warm ischemia. Graft viability is influenced by both the quantity and quality of warm ischemia, which is unique to each donor and causes various degrees of pathophysiologic consequences. Evidence also shows that the choice of preservation solution and premortem heparin administration influences graft viability. Additionally, although the precise mechanism of IC remains unknown, stasis of blood during donor warm ischemia may cause the formation of microthrombi in the peribiliary vascular plexus and ischemia of the bile duct. Importantly, thrombolytic protocols show a possible preventive modality for IC. Finally, while ex vivo machine perfusion technology has gained an interest in DCD liver transplantation, further studies are necessary to evaluate the effectiveness of this evolving field to improve graft quality and transplant outcomes.

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.

Donation after circulatory death liver transplantation: What are the limits for an acceptable DCD graft?

The utilization of donation after circulatory death (DCD) livers has been growing over the last decade. In large-volume centers, survival outcomes have improved and are comparable to outcomes with brain death donor (DBD) liver transplantation (LT). The relatively concentrated success with DCD LT demonstrated by high-volume transplant centers has rekindled international enthusiasm. The combination of increasing expertise in DCD LT and ongoing shortage in transplantable organs has promoted expansion of the DCD donor pool with regards to donor age, body mass index and donor warm ischemia time. In this review, we focused on the practice patterns in DCD liver graft utilization in the last decade, along with the possibilities for further expansion of DCD liver graft utilization and new technologies, such as machine perfusion.

Top Papers in Liver Transplantation 2017-2018

Organ shortage remains a major limitation in liver transplantation, and there has been a significant effort over the past decade to increase the existing deceased donor pool. Recent advances have included better selection and management of donors after circulatory arrest, application of hypothermic and normothermic perfusion, minimization of standard immunosuppression, and use of new immunosuppressive medications. Additionally, there has been renewed emphasis and understanding of liver immunology and the impact of antibody-mediated rejection. Together, these advances have allowed for expansion of the donor pool with concurrent improved patient outcomes. Furthermore, direct-acting antiviral agents for the treatment of hepatitis C virus infection has been management of this infection. These changes have affected the practice of solid organ transplantation by altering the framework by which patients with end-stage organ disease are managed and receive organ transplants. In this article, we analyze some of the top papers published in 2017-2018 dealing with these issues.

Addressing organ shortages: progress in donation after circulatory death for liver transplantation

Reducing wait list mortality among patients awaiting liver transplantation remains a substantial challenge because of organ shortage. In efforts to expand the donor pool there has been a trend toward increased use of donation after circulatory death (DCD) liver grafts. However, these marginal grafts are prone to higher complication rates, particularly biliary complications. In addition, many procured DCD livers are then deemed unsuitable for transplant. Despite these limitations, DCD grafts represent an important resource to address the current organ shortage, and as such there are research efforts directed toward improving the use of and outcomes for transplantation of these grafts. We review the current progress in DCD liver transplantation.

Transplant Outcomes of Donation After Circulatory Death Livers Recovered With Versus Without Premortem Heparin Administration

Premortem heparin administration during donation after circulatory death (DCD) organ recovery is thought to optimize liver perfusion. However, premortem heparinization is not universally practiced in the United States and limited data exist regarding its utility. US registry data were accessed between January 1, 2003, and March 10, 2017, and 2 cohorts were ascertained: (1) DCD donor livers recovered for transplantation (n = 5495) and (2) liver-only adult transplant recipients of DCD livers (n = 3754). Exclusions were donor unknown heparin status (n = 40), positive donor hepatitis B surface antigen (n = 4) and hepatitis C virus (n = 120) serologies, and for the outcomes analysis, livers placed outside the United States (n = 10). Discard rates and graft outcomes were examined from cohorts 1 and 2, respectively. Of 5495 DCD livers recovered for transplant, 589 (10.7%) donors did not receive premortem heparin (no heparin) and the remaining 4906 (89.3%) received heparin (heparin). Liver discard was similar between the no heparin (30.6%) and heparin groups (30.8%; P = 0.90). Heparin status was not associated with liver discard on multivariate analysis (adjusted odds ratio, 0.97; 95% confidence interval [CI], 0.80-1.18 P = 0.76). The cumulative probability of overall graft survival was lower in the no heparin group relative to the heparin group (P < 0.05), and this finding persisted on multivariate analysis. No heparin group transplants had an 18% higher hazard of overall graft failure compared with those that received heparin (adjusted hazard ratio, 1.18; 95% CI, 1.01-1.38; P < 0.05). In conclusion, organ recovery heparin administration status was not associated with liver discard. Failure to pretreat organ donors with premortem heparin correlates with worse liver transplant graft survival compared with heparin-treated livers.

Avoiding initial hypothermia does not improve liver graft quality in a porcine donation after circulatory death (DCD) model of normothermic perfusion

Background

Normothermic machine perfusion (NMP) of liver grafts donated after circulatory death (DCD) has shown promise in large animal and clinical trials. Following procurement, initial flush with a cold preservation solution is the standard of care. There is concern that initial cooling followed by warming may exacerbate liver injury, and the optimal initial flush temperature has yet to be identified. We hypothesize that avoidance of the initial cold flush will yield better quality liver grafts.

Methods

Twenty-four anaesthetized pigs were withdrawn from mechanical ventilation and allowed to arrest. After 60-minutes of warm ischemia to simulate a DCD procurement, livers were flushed with histidine-tryptophan-ketoglutarate (HTK) at 4°C, 25°C or 35°C (n = 4 per group). For comparison, an adenosine-lidocaine crystalloid solution (AD), shown to have benefit at warm temperatures in heart perfusions, was also used (n = 4 per group). During 12-hours of NMP, adenosine triphosphate (ATP), lactate, transaminase levels, and histological injury were determined. Bile production and hemodynamics were monitored continuously.

Results

ATP levels recovered substantially following 1-hour of NMP reaching pre-ischemic levels by the end of NMP with no difference between groups. There was no difference in peak aspartate aminotransferase (AST) or in lactate dehydrogenase (LDH). Portal vein resistance was lowest in the 4°C group reaching significance after 2 hours (0.13 CI -0.01,0.277, p = 0.025). Lactate levels recovered promptly with no difference between groups. Comparison to AD groups showed no statistical difference in the abovementioned parameters. On electron microscopy the HTK4°C group had the least edema with mean cell thickness of 2.92μm (p = 0.41) while also having the least sinusoidal dilatation with a mean diameter of 5.36μm (p = 0.04). For AD, the 25°C group had the lowest mean cell thickness at 3.14μm (p = 0.09).

Conclusions

Avoidance of the initial cold flush failed to demonstrate added benefit over standard 4°C HTK in this DCD model of liver perfusion.

Oxygenated UW Solution Decreases ATP Decay and Improves Survival After Transplantation of DCD Liver Grafts

BACKGROUND

Donation after circulatory death (DCD) liver grafts are known to be predisposed to primary nonfunction and ischemic cholangiopathy. Many DCD grafts are discarded because of older donor age or long warm ischemia times. Thus, it is critical to improve the quality of DCD liver grafts. Here, we have tested whether an enriched oxygen carrier added to the preservation solution can prolong graft survival and reduce biliary damage.

METHODS

We assessed the adenosine triphosphate (ATP) content decay of mouse liver grafts after cold ischemia, warm ischemia, and combined warm+cold ischemia. In addition, we used a rat model of liver transplantation to compare survival of DCD grafts preserved in high-oxygen solution (preoxygenated perfluorocarbon [PFC] + University of Wisconsin [UW] solution) versus lower oxygen solution (preoxygenated UW solution).

RESULTS

Adenosine triphosphate levels under UW preservation fall to less than 10% after 30 minutes of warm ischemia. Preoxygenated UW solution with PFC reached a significantly higher PaO2. After 45 minutes of warm ischemia in oxygenated UW + PFC solution, grafts showed 63% higher levels of ATP (P = 0.011). In addition, this was associated with better preservation of morphology when compared to grafts stored in standard UW solution. Animals that received DCD grafts preserved in higher oxygenation solution showed improved survival: 4 out of 6 animals survived long-term whereas all control group animals died within 24 hours.

CONCLUSIONS

The additional oxygen provided by PFC during static cold preservation of DCD livers can better sustain ATP levels, and thereby reduce the severity of ischemic tissue damage. PFC-based preservation solution extends the tolerance to warm ischemia, and may reduce the rate of ischemic cholangiopathy.

Human Atrial Natriuretic Peptide in Cold Storage of Donation After Circulatory Death Rat Livers: An Old but New Agent for Protecting Vascular Endothelia?

BACKGROUND

Current critical shortage of donor organs has increased the use of donation after circulatory death (DCD) livers for transplantation, despite higher risk for primary nonfunction or ischemic cholangiopathy. Human atrial natriuretic peptide (hANP) is a cardiovascular hormone that possesses protective action to vascular endothelia. We aimed to clarify the therapeutic potential of hANP in cold storage of DCD livers.

METHODS

Male Wistar rats were exposed to 30-minute warm ischemia in situ. Livers were then retrieved and cold-preserved for 6 hours with or without hANP supplementation. Functional and morphological integrity of the livers was evaluated by oxygenated ex vivo reperfusion at 37°C.

RESULTS

hANP supplementation resulted in significant reduction of portal venous pressure (12.2 ± 0.5 versus 22.5 ± 3.5 mm Hg, P < 0.001). As underlying mechanisms, hANP supplementation significantly increased tissue adenosine concentration (P = 0.008), resulting in significant upregulation of endothelial nitric oxide synthase and significant downregulation of endothelin-1 (P = 0.01 and P = 0.004 vs. the controls, respectively). Consequently, hANP significantly decreased transaminase release (P < 0.001) and increased bile production (96.2 ± 18.2 versus 36.2 ± 15.2 μL/g-liver/h, P < 0.001). Morphologically, hepatocytes and sinusoidal endothelia were both better maintained by hANP (P = 0.021). Electron microscopy also revealed that sinusoidal ultrastructures and microvilli formation in bile canaliculi were both better preserved by hANP supplementation. Silver staining also demonstrated that hANP significantly preserved reticulin fibers in Disse space (P = 0.017), representing significant protection of sinusoidal frameworks/architectures.

CONCLUSIONS

Supplementation of hANP during cold storage significantly attenuated cold ischemia/warm reperfusion injury of DCD livers.

Expanding the Donor Pool With the Use of Extended Criteria Donation After Circulatory Death Livers

Use of donation after circulatory death (DCD) donor livers for transplantation has remained cautious in the United States. The aim of this study was to demonstrate the expansion of a DCD liver transplantation (LT) program with the use of extended criteria donor (ECD) DCD livers. After institutional review board approval, 135 consecutive DCD LTs were retrospectively studied. ECD DCD livers were defined as those with 1 of the following factors: donor age >50 years, donor body mass index >35 kg/m² , donor functional warm ischemia time >30 minutes, and donor liver macrosteatosis >30%. An optimization protocol was introduced in July 2011 to improve outcomes of DCD LT, which included thrombolytic donor flush and efforts to minimize ischemia times. The impact of this protocol on outcomes was evaluated in terms of graft loss, ischemic cholangiopathy (IC), and change in DCD LT volume. Of 135 consecutive DCD LTs, 62 were ECD DCDs. In total, 24 ECD DCD LTs were performed before (era 1) and 38 after the institution of optimization protocol (era 2), accounting for an increase in the use of ECD DCD livers from 39% to 52%. Overall outcomes of ECD DCD LT improved in era 2, with a significantly lower incidence of IC (5% versus 17% in era 1; P = 0.03) and better 1-year graft survival (93% versus 75% in era 1; P = 0.07). Survival outcomes for ECD DCD LT in era 2 were comparable to matched deceased donor LT. With the expansion of the DCD donor pool, the number of DCD LTs performed at our center gradually increased in era 2 to account for >20% of the center's LT volume. In conclusion, with the optimization of perioperative conditions, ECD DCD livers can be successfully transplanted to expand the donor pool for LT.

Heterogeneity of Bile Duct Management in the Development of Ischemic Cholangiopathy After Liver Transplantation: Results of a European Liver and Intestine Transplant Association Survey

BACKGROUND

Surgical factors and direct cytotoxicity of bile salts on cholangiocytes may play a role in the development of ischemic cholangiopathy (IC) after liver transplantation (LTx). There is no validated consensus on how to protect the bile ducts during procurement, static preservation, and LTx. Meanwhile, IC remains the most troublesome complication after LTx.

AIM

To characterize bile duct management techniques during the LTx process among European transplant centers in cases of donation after brain death (DBD) and circulatory death (DCD).

METHOD

An European Liver and Intestine Transplant Association-European Liver Transplant Registry web survey designed to conceal respondents' personal information was sent to surgeons procuring and/or transplanting livers in Europe.

RESULTS

Sixty-five percent of responses came from large transplant centers (>50 procurements/y). In 8% of DBDs and 14% of DCDs the bile duct is not rinsed. In 46% of DBDs and 52% of DCDs surgeons prefer to remove the gallbladder after graft reperfusion. Protocols concerning preservation solutions (nature, pressure, volume) are extremely heterogeneous. In 54% of DBDs and 61% of DCDs an arterial back table pressure perfusion is performed. Steroids (20%-10%), heparin (72%-60%), prostacyclin (3%-7%), and fibrinolytics (4%-11%) are used as donor-protective interventions in DBD and DCD cases, respectively. In 2% of DBD and 6% of DCD cases a hepatic artery reperfusion is performed first. In 4% of DBD and 6% of DCD cases, fibrinolytics are administered through the hepatic artery during the bench and/or implantation.

CONCLUSION

This European web survey shows for the first time the heterogeneity in the management of bile ducts during procurement, preservation, and transplantation in Europe. In the context of sharing more marginal liver grafts, an expert meeting must be organized to formulate guidelines to be applied to protect liver grafts against IC.

In situ normothermic perfusion of livers in controlled circulatory death donation may prevent ischemic cholangiopathy and improve graft survival

Livers from controlled donation after circulatory death (DCD) donors suffer a higher incidence of nonfunction, poor function, and ischemic cholangiopathy. In situ normothermic regional perfusion (NRP) restores a blood supply to the abdominal organs after death using an extracorporeal circulation for a limited period before organ recovery. We undertook a retrospective analysis to evaluate whether NRP was associated with improved outcomes of livers from DCD donors. NRP was performed on 70 DCD donors from whom 43 livers were transplanted. These were compared with 187 non-NRP DCD donor livers transplanted at the same two UK centers in the same period. The use of NRP was associated with a reduction in early allograft dysfunction (12% for NRP vs. 32% for non-NRP livers, P = .0076), 30-day graft loss (2% NRP livers vs. 12% non-NRP livers, P = .0559), freedom from ischemic cholangiopathy (0% vs. 27% for non-NRP livers, P < .0001), and fewer anastomotic strictures (7% vs. 27% non-NRP, P = .0041). After adjusting for other factors in a multivariable analysis, NRP remained significantly associated with freedom from ischemic cholangiopathy (P < .0001). These data suggest that NRP during organ recovery from DCD donors leads to superior liver outcomes compared to conventional organ recovery.

Liver graft preservation methods during cold ischemia phase and normothermic machine perfusion

The growing demand for donor organs requires measures to expand donor pool. Those include extended criteria donors, such as elderly people, steatotic livers, donation after cardiac death, etc. Static cold storage to reduce metabolic requirements developed by Collins in late 1960s is the mainstay and the golden standard for donated organ protection. Hypothermic machine perfusion provides dynamic organ preservation at 4°C with protracted infusion of metabolic substrates to the graft during the ex vivo period. It has been used instead of static cold storage or after it as short perfusion in transplant center. Normothermic machine perfusion (NMP) delivers oxygen, and nutrition at physiological temperature mimicking regular environment in order to support cellular function. This would minimize effects of ischemia/reperfusion injury. Potentially, NMP may help to estimate graft functionality before implantation into a recipient. Clinical studies demonstrated at least its non-inferiority or better outcomes vs static cold storage. Regular grafts donated after brain death could be safely preserved with convenient static cold storage. Except for prolonged ischemia time where hypothermic machine perfusion started in transplant center could be estimated to provide possible positive reconditioning effect. Use of hypothermic machine perfusion in regular donation instead of static cold storage or in extended criteria donors requires further investigation. Multicenter randomized clinical trial supposed to be completed in December 2021. Extended criteria donors need additional measures for graft storage and assessment until its implantation. NMP is actively evaluating promising method for this purpose. Future studies are necessary for precise estimation and confirmation to issue clinical practice recommendations.

The efficacy of extracorporeal membrane oxygenation in liver transplantation from non-heart-beating donors: A systemic review and meta-analysis

BACKGROUND

A systematic review and meta-analysis was made to see whether extracorporeal membrane oxygenation (ECMO) in liver transplantation could improve non-heart-beating donors (NHBDs) recipients' outcomes compared with donors after brain death (DBDs) recipients.

METHODS

We searched MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials for eligible studies. The study eligible criteria are cohort or case-control studies using ECMO in all NHBDs; studies involved a comparison group of DBDs; and studies evaluated 1-year graft and patient survival rate in NHBDs and DBDs groups.

RESULTS

Four studies with 704 patients fulfilled the inclusion criteria. The pooled odds ratio (OR) of 1-year patient survival rate in NHBDs recipients compared with DBDs recipients was 0.8 (95% confidence interval [CI], 0.41-1.55). The pooled OR of 1-year graft survival rate in NHBDs recipients compared with DBDs recipients was 0.46 (95% CI, 0.26-0.81). NHBDs recipients were at greater risks to the occurrence of primary nonfunction (PNF) (OR = 7.12, 95% CI, 1.84-27.52) and ischemic cholangiopathy (IC) (OR = 9.46, 95% CI, 2.76-32.4) than DBDs recipients.

CONCLUSIONS

ECMO makes 1-year patient survival acceptable in NHBDs recipients. One-year graft survival rate was lower in NHBDs recipients than in DBDs recipients. Compared with DBDs recipients, the risks to develop PNF and IC were increased among NHBDs recipients.

Systematic Review and Meta-Analysis on the Impact of Thrombolytic Therapy in Liver Transplantation Following Donation after Circulatory Death

Aim: The livers from DCD (donation after cardiac death) donations are often envisaged as a possible option to bridge the gap between the availability and increasing demand of organs for liver transplantation. However, DCD livers possess a heightened risk for complications and represent a formidable management challenge. The aim of this study was to evaluate the effects of thrombolytic flush in DCD liver transplantation. Methods: An extensive search of the literature database was made on MEDLINE, EMBASE, Cochrane, Crossref, Scopus databases, and clinical trial registry on 20 September 2018 to assess the role of thrombolytic tissue plasminogen activator (tPA) flush in DCD liver transplantation. Results: A total of four studies with 249 patients in the tPA group and 178 patients in the non-tPA group were included. The pooled data revealed a significant decrease in ischemic-type biliary lesions (ITBLs) (P = 0.04), re-transplantation rate (P = 0.0001), and no increased requirement of blood transfusion (P = 0.16) with a better one year graft survival (P = 0.02). Conclusions: To recapitulate, tPA in DCD liver transplantation decreased the incidence of ITBLs, re-transplantation and markedly improved 1-year graft survival, without any increased risk for blood transfusion, hence it has potential to expand the boundaries of DCD liver transplantation.

Expanding the donor pool: Donation after circulatory death and living liver donation do not compromise the results of liver transplantation

Because of the shortfall between the number of patients listed for liver transplantation (LT) and the available grafts, strategies to expand the donor pool have been developed. Donation after circulatory death (DCD) and living donor (LD) grafts are not universally used because of the concerns of graft failure, biliary complications, and donor risks. In order to overcome the barriers for the implementation of using all 3 types of grafts, we compared outcomes after LT of DCD, LD, and donation after brain death (DBD) grafts. Patients who received a LD, DCD, or DBD liver graft at the University of Toronto were included. Between January 2009 through April 2017, 1054 patients received a LT at our center. Of these, 77 patients received a DCD graft (DCD group); 271 received a LD graft (LD group); and 706 received a DBD graft (DBD group). Overall biliary complications were higher in the LD group (11.8%) compared with the DCD group (5.2%) and the DBD group (4.8%; P < 0.001). The 1-, 3-, and 5-year graft survival rates were similar between the groups with 88.3%, 83.2%, and 69.2% in the DCD group versus 92.6%, 85.4%, and 84.7% in the LD group versus 90.2%, 84.2%, and 79.9% in the DBD group (P = 0.24). Furthermore, the 1-, 3-, and 5-year patient survival was comparable, with 92.2%, 85.4%, and 71.6% in the DCD group versus 95.2%, 88.8%, and 88.8% in the LD group versus 93.1%, 87.5%, and 83% in the DBD group (P = 0.14). Multivariate Cox regression analysis revealed that the type of graft did not impact graft survival. In conclusion, DCD, LD, and DBD grafts have similar longterm graft survival rates. Increasing the use of LD and DCD grafts may improve access to LT without affecting graft survival rates. Liver Transplantation 24 779-789 2018 AASLD.

The Role of Normothermic Perfusion in Liver Transplantation (TRaNsIT Study): A Systematic Review of Preliminary Studies

INTRODUCTION

The success of liver transplantation has been limited by the unavailability of suitable donor livers. The current organ preservation technique, i.e., static cold storage (SCS), is not suitable for marginal organs. Alternatively, normothermic machine perfusion (NMP) promises to recreate the physiological environment and hence holds promise for the better organ preservation. The objective of this systematic review is to provide an overview of the safety, benefits, and insight into the other potential useful parameters of NMP in the liver preservation.

MATERIAL AND METHODS

We searched the current literature following registration in the International Prospective Register of Systematic Reviews (PROSPERO) with registration number CRD42018086034 for prospective trials comparing the role of NMP device to SCS in liver transplant by searching the PubMed, EMBASE, Cochrane, BIOSIS, Crossref, and Scopus databases and clinical trial registry.

RESULTS

The literature search identified five prospective clinical trials (four being early phase single institutional and single randomized multi-institutional) comparing 187 donor livers on NMP device to 273 donor livers on SCS. The primary outcome of interest was to assess the safety and graft survival at day 30 after transplant following NMP of the donor liver. Secondary outcomes included were early allograft dysfunction (EAD) in the first seven days; serum measures of liver functions as bilirubin, aspartate aminotransferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), and international normalized ratio (INR) on days 1-7; major complications as defined by a Clavien-Dindo score ≥ 3; and patient and graft survival and biliary complications at six months. The peaked median AST level between days 1 and 7 in the five trials was 417-1252 U/L (range 84-15009 U/L) while on NMP and 839-1474 U/L (range 153-8786 U/L) in SCS group. The median bilirubin level on day 7 ranged within 25-79 µmol/L (range 8-344 µmol/l) and 30-47.53 µmol/l (range 9-340 µmol/l) in NMP and SCS groups, respectively. A single case of PNF was reported in NMP group in the randomized trial while none of the other preliminary studies reported any in either group. There was intertrial variability in EAD which ranged within 15-56% in NMP group while being within 23-37% in SCS group. Biliary complications observed in NMP group ranged from 0 to 20%. Single device malfunction was reported in randomized controlled trial leading to renouncement of transplant while none of the other trials reported any machine failure, although two user related device errors inadvertent were reported.

CONCLUSION

This review outlines that NMP not only demonstrated safety and efficacy but also provided the favourable environment of organ preservation, repair, and viability assessment to donor liver prior to the transplantation with low rate of posttransplantation complication as PNF, EAD, and biliary complication; however further studies are needed to broaden our horizon.

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.

A literature-based cost analysis of tissue plasminogen activator for prevention of biliary stricture in donation after circulatory death liver transplantation

INTRODUCTION

This study sought to approximate the cost-effectiveness of tPA utilization for prevention of biliary strictures (PTBS) in donation after circulatory death liver transplantation (DCD-LT).

METHODS

Previously-reported PTBS rates in DCD-LT with and without tPA were used to calculate the number needed to treat (NNT) for prevention of one PTBS. The incremental cost of PTBS was then used to determine the cost effectiveness of tPA for prevention of PTBS.

RESULTS

The incidence of PTBS in the setting of tPA administration was 20%, while incidence in patients without tPA use was 43% (p < 0.001). Meta-analysis demonstrated a risk reduction of 15.7%, which translated into a NNT of 6.4. Cost associated with treating 6.4 patients was $50,353. Based on an incremental cost of $81,888 associated with PTBS management, use of tPA in DCD-LT protocols was estimated to save $31,528 per PTBS prevented.

CONCLUSION

Utilization of tPA in DCD-LT protocols represents one possible cost-effective strategy for prevention of PTBS in DCD-LT.

Attitudes and barriers to the use of donation after cardiac death livers: Comparison of a United States transplant center survey to the united network for organ sharing data

Transplantation of liver grafts from donation after cardiac death (DCD) is limited. To identify barriers of DCD liver utilization, all active US liver transplant centers (n = 138) were surveyed, and the responses were compared with the United Network for Organ Sharing (UNOS) data. In total, 74 (54%) centers responded, and diversity in attitudes was observed, with many not using organ and/or recipient prognostic variables defined in prior studies and UNOS data analysis. Most centers (74%) believed lack of a system allowing a timely retransplant is a barrier to utilization. UNOS data demonstrated worse 1- and 5-year patient survival (PS) and graft survival (GS) in DCD (PS, 86% and 64%; GS, 82% and 59%, respectively) versus donation after brain death (DBD) recipients (PS, 90% and 71%; GS, 88% and 69%, respectively). Donor alanine aminotransferase (ALT), recipient Model for End-Stage Liver Disease (MELD), and cold ischemia time (CIT) significantly impacted DCD outcomes to a greater extent than DBD outcomes. At 3 years, relisting and retransplant rates were 7.9% and 4.6% higher in DCD recipients. To optimize outcome, our data support the use of DCD liver grafts with CIT <6-8 hours in patients with MELD ≤ 20. In conclusion, standardization of donor and recipient criteria, defining the impact of ischemic cholangiopathy, addressing donor hospital policies, and developing a strategy for timely retransplant may help to expand the use of these organs. Liver Transplantation 23 1372-1383 2017 AASLD.