Homotransplantation of the liver

Organ Donation After Out-of-Hospital Cardiac Arrest: A Scientific Statement From the International Liaison Committee on Resuscitation

AIM OF THE REVIEW

Improving rates of organ donation among patients with out-of-hospital cardiac arrest who do not survive is an opportunity to save countless lives. The objectives of this scientific statement were to do the following: define the opportunity for organ donation among patients with out-of-hospital cardiac arrest; identify challenges and opportunities associated with organ donation by patients with cardiac arrest; identify strategies, including a generic protocol for organ donation after cardiac arrest, to increase the rate and consistency of organ donation from this population; and provide rationale for including organ donation as a key clinical outcome for all future cardiac arrest clinical trials and registries.

METHODS

The scope of this International Liaison Committee on Resuscitation scientific statement was approved by the International Liaison Committee on Resuscitation board and the American Heart Association, posted on ILCOR.org for public comment, and then assigned by section to primary and secondary authors. A unique literature search was completed and updated for each section.

RESULTS

There are a number of defining pathways for patients with out-of-hospital cardiac arrest to become organ donors; however, modifications in the Maastricht classification system need to be made to correctly identify these donors and to report outcomes with consistency. Suggested modifications to the minimum data set for reporting cardiac arrests will increase reporting of organ donation as an important resuscitation outcome. There are a number of challenges with implementing uncontrolled donation after cardiac death protocols, and the greatest impediment is the lack of legislation in most countries to mandate organ donation as the default option. Extracorporeal cardiopulmonary resuscitation has the potential to increase organ donation rates, but more research is needed to derive neuroprognostication rules to guide clinical decision-making about when to stop extracorporeal cardiopulmonary resuscitation and to evaluate cost-effectiveness.

CONCLUSIONS

All health systems should develop, implement, and evaluate protocols designed to optimize organ donation opportunities for patients who have an out-of-hospital cardiac arrest and failed attempts at resuscitation.

Organ Donation After Out-of-Hospital Cardiac Arrest: A Scientific Statement From the International Liaison Committee on Resuscitation

AIM OF THE REVIEW

Improving rates of organ donation among patients with out-of-hospital cardiac arrest who do not survive is an opportunity to save countless lives. The objectives of this scientific statement were to do the following: define the opportunity for organ donation among patients with out-of-hospital cardiac arrest; identify challenges and opportunities associated with organ donation by patients with cardiac arrest; identify strategies, including a generic protocol for organ donation after cardiac arrest, to increase the rate and consistency of organ donation from this population; and provide rationale for including organ donation as a key clinical outcome for all future cardiac arrest clinical trials and registries.

METHODS

The scope of this International Liaison Committee on Resuscitation scientific statement was approved by the International Liaison Committee on Resuscitation board and the American Heart Association, posted on ILCOR.org for public comment, and then assigned by section to primary and secondary authors. A unique literature search was completed and updated for each section.

RESULTS

There are a number of defining pathways for patients with out-of-hospital cardiac arrest to become organ donors; however, modifications in the Maastricht classification system need to be made to correctly identify these donors and to report outcomes with consistency. Suggested modifications to the minimum data set for reporting cardiac arrests will increase reporting of organ donation as an important resuscitation outcome. There are a number of challenges with implementing uncontrolled donation after cardiac death protocols, and the greatest impediment is the lack of legislation in most countries to mandate organ donation as the default option. Extracorporeal cardiopulmonary resuscitation has the potential to increase organ donation rates, but more research is needed to derive neuroprognostication rules to guide clinical decision-making about when to stop extracorporeal cardiopulmonary resuscitation and to evaluate cost-effectiveness.

CONCLUSIONS

All health systems should develop, implement, and evaluate protocols designed to optimise organ donation opportunities for patients who have an out-of-hospital cardiac arrest and failed attempts at resuscitation.

Invasive Fungal Infections: The Early Killer after Liver Transplantation

BACKGROUND

Liver transplantation is a standard of care and a life-saving procedure for end-stage liver diseases and certain malignancies. The evidence on predictors and risk factors for poor outcomes is lacking. Therefore, we aimed to identify potential risk factors for mortality and to report on overall 90-day mortality after orthotopic liver transplantation (OLT), especially focusing on the role of fungal infections.

METHODS

We retrospectively reviewed medical charts of all patients undergoing OLT at a tertiary university center in Europe.

RESULTS

From 299 patients, 214 adult patients who received a first-time OLT were included. The OLT indication was mainly due to tumors (42%, 89/214) and cirrhosis (32%, 68/214), including acute liver failure in 4.7% (10/214) of patients. In total, 8% (17/214) of patients died within the first three months, with a median time to death of 15 (1-80) days. Despite a targeted antimycotic prophylaxis using echinocandins, invasive fungal infections occurred in 12% (26/214) of the patients. In the multivariate analysis, patients with invasive fungal infections had an almost five times higher chance of death (HR 4.6, 95% CI 1.1-18.8; p = 0.032).

CONCLUSIONS

Short-term mortality after OLT is mainly determined by infectious and procedural complications. Fungal breakthrough infections are becoming a growing concern. Procedural, host, and fungal factors can contribute to a failure of prophylaxis. Finally, invasive fungal infections may be a potentially modifiable risk factor, but the ideal perioperative antimycotic prophylaxis has yet to be determined.

Inducible Co-Stimulator (ICOS) in transplantation: A review

Prevention of T cell activation is one of the goals of successful organ and tissue transplantation. Blockade of T cell co-stimulation, particularly of the CD28:B7 interaction, has been shown to prolong graft survival. Inducible Co-Stimulator (ICOS) is the third member of the B7 family and here we review the literature on ICOS, its receptor (B7RP-1), and blockade of this pathway in transplant models. ICOS:B7RP-1 are a single receptor:ligand pair with a loss of function of either being implicated in some autoimmune diseases. ICOS has multiple functions, related to its constitutive expression on B cells and activated T cells. In in vitro transplant models, ICOS:B7RP-1 blockade has produced mixed results as to its ability to modulate lymphocyte proliferation. Several in vivo transplant models demonstrate varying degrees of success in prolonging graft survival. Timing and dose of treatment appear important, and combination with other immunosuppressive treatments may also be of benefit. As ICOS has multiple functions, it may be that the observed variable results are due to inadvertent inactivation of graft protective functions. If these barriers can be overcome, ICOS:B7RP-1 blockade could provide an important target for future immunosuppression regimens.

Intraoperative Doppler Ultrasound for Detection of Early Postoperative Vascular Complications in Orthotopic Liver Transplants

Liver transplantation is currently the only curative treatment for patients with end-stage liver disease. However, liver transplantation can be associated with catastrophic complications in the early postoperative setting, including hepatic artery thrombosis (HAT) and portal vein thrombosis (PVT). Postoperative complications are associated with hepatic artery resistive index (RI) < 6, systolic acceleration time (SAT) > 0.08 seconds and peak systolic velocity (PSV) > 200 cm/s on doppler ultrasound (DUS). DUS is also used in an intraoperative setting to assess patency and early complications prior to the end of the operative period, allowing for early correction. This literature review evaluates the prevalence of DUS use in intraoperative settings to identify transplant complications. A lack of consistency and minimal knowledge of intraoperative DUS warrants additional research into its usage and standardization.

Clinical Outcomes of Liver Transplantation for Patients Over 60 Years Old: A Single-Center Experience

OBJECTIVES

Although advanced age is no longer considered an absolute contraindication for liver transplant, transplant in elderly patients with comorbid diseases remains debatable because of high risks with surgery. Here, we report patient outcomes in this population.

MATERIALS AND METHODS

We retrospectively reviewed medical records of 276 liver transplant recipients, grouped by age. Group 1 (≤59 years old) consisted of 247 recipients, and group 2 (≥60 years old) consisted of 29 recipients. Reviewed data included age, sex, cause of liver disease, presence of hepatocellular carcinoma, Child-Pugh and Model for End-Stage Liver Disease scores, survival, and posttransplant complications.

RESULTS

In both groups, most patients (n = 108) required liver transplant for hepatitis B virus. Mean age was 40 ± 12.3 and 63 ± 2.3 years in groups 1 and 2, respectively, with more men than women in both group 1 (71.7% vs 28.3%) and group 2 (75.9% vs 24.1%). No significant differences were shown between groups for patient characteristics, except group 1 had significantly higher Model for End-Stage Liver Disease score. Group 1 mean survival time was 10.2 ± 0.6 years, with patient survival rates at 1, 5, 10, and 15 years of 65.5%, 53%, 46.3%, and 40%, respectively. In group 2, respective results were 10.6 ± 1.3 years and 75.9%, 68.6%, 61%, and 48.8% (no significant difference vs group 1).

CONCLUSIONS

Liver transplant recipients >60 years of age had survival rates, acute rejection rates, and complications similar to younger recipients. Liver transplant should not be withheld from older recipients on the basis of age alone. However, comprehensive screening for comorbidities should be performed.

Application of various surgical techniques in liver transplantation: a retrospective study

Background

Surgical techniques of liver transplantation have continually evolved and have been modified. We retrospectively analyzed a single-center case series and compared the advantages and disadvantages of each method.

Methods

Six-hundred and seventy-four recipients’ perioperative data were assessed and analyzed stratified by different surgical technics [modified classic (MC), modified piggyback (MPB) and classic piggyback (CPB)].

Results

MELD score and Child-Pugh scores was significantly higher in CPB groups (P=0.008 and 0.003, respectively). Anhepatic time in MPB group was longer than those in CPB group (P<0.05). The operation duration in MPB group was significantly longer than those in MC group and CPB group (P=0.003). Three patients had outflow obstruction (P=0.035). The overall survival in MPB group were better than those in MC group and CPB group in general comparison (P<0.001). In patients with preoperative creatine >120 µmol/L, the overall survival in MC group was worst (P<0.001). In patients with a high MELD score (>24), the overall survival in MPB group tended to be the best (P<0.001).

Conclusions

The advantages and disadvantages are different for these three surgical techniques. A reasonable operation technique should be adopted considering the patient's unique condition to ensure the stability of hemodynamics.

Transcriptome and Exome Analyses of Hepatocellular Carcinoma Reveal Patterns to Predict Cancer Recurrence in Liver Transplant Patients

Hepatocellular carcinoma (HCC) is one of the most lethal human cancers. Liver transplantation has been an effective approach to treat liver cancer. However, significant numbers of patients with HCC experience cancer recurrence, and the selection of suitable candidates for liver transplant remains a challenge. We developed a model to predict the likelihood of HCC recurrence after liver transplantation based on transcriptome and whole‐exome sequencing analyses. We used a training cohort and a subsequent testing cohort based on liver transplantation performed before or after the first half of 2012. We found that the combination of transcriptome and mutation pathway analyses using a random forest machine learning correctly predicted HCC recurrence in 86.8% of the training set. The same algorithm yielded a correct prediction of HCC recurrence of 76.9% in the testing set. When the cohorts were combined, the prediction rate reached 84.4% in the leave‐one‐out cross‐validation analysis. When the transcriptome analysis was combined with Milan criteria using the k‐top scoring pairs (k‐TSP) method, the testing cohort prediction rate improved to 80.8%, whereas the training cohort and the combined cohort prediction rates were 79% and 84.4%, respectively. Application of the transcriptome/mutation pathways RF model on eight tumor nodules from 3 patients with HCC yielded 8/8 consistency, suggesting a robust prediction despite the heterogeneity of HCC. Conclusion: The genome prediction model may hold promise as an alternative in selecting patients with HCC for liver transplant.

New Indications for Liver Transplantation

Liver transplantation (LT) is an important therapeutic option for the treatment of several liver diseases. Modern LT is characterized by remarkable improvements in post-transplant patient survival, graft survival, and quality of life. Thanks to these great improvements, indications for LT are expanding. Nowadays, clinical conditions historically considered exclusion criteria for LT, have been considered new indications for LT, showing survival advantages for patients. In this review, we provide an updated overview of the principal newer indications for LT, with particular attention to alcoholic hepatitis, acute-on-chronic liver failure (ACLF), cholangiocarcinoma and colorectal cancer metastases.

Current review of machine perfusion in liver transplantation from the Japanese perspective

In light of the present evidence, machine perfusion is opening up new horizons in the field of liver transplantation. Although many advances have been made in liver transplantation, organ preservation methods have so far changed very little. Static cold storage is universally used for graft preservation in liver transplantation; however, there is a need for better preservation methods, such as ex vivo machine perfusion, to improve the outcomes by decreasing warm ischemic damage. Based on the findings of basic and clinical trials, hypothermic and normothermic machine perfusion techniques are now commercially available and include the OrganOx metra, Liver Assist, Cleveland NMP device, Organ Care System, and LifePort Liver. Recent clinical trials have provided further evidence for the potential role of normothermic machine perfusion to resuscitate and subsequently improve utilization of marginal or currently discarded livers. Further studies are required to explore the longer-term outcomes, late biliary complications, outcomes in specific high-risk groups, viability biomarkers, optimum and maximum perfusion duration, perfusate composition, and liver-directed therapeutic interventions during normothermic machine perfusion. The use of organs from marginal donors after brain death, such as fatty livers and the livers from elderly donors with multiple comorbidities, may be accepted for machine perfusion in Japan in the near future.

Thirty Years of Tacrolimus in Clinical Practice

Tacrolimus was discovered in 1984 and entered clinical use shortly thereafter, contributing to successful solid organ transplantation across the globe. In this review, we cover development of tacrolimus, its evolving clinical utility, and issues affecting its current usage. Since earliest use of this class of immunosuppressant, concerns for calcineurin-inhibitor toxicity have led to efforts to minimize or eliminate these agents in clinical regimens but with limited success. Current understanding of the role of tacrolimus focuses more on its efficacy in preventing graft rejection and graft loss. As we enter the fourth decade of tacrolimus use, newer studies utilizing novel combinations (as with the mammalian target of rapamycin inhibitor, everolimus, and T-cell costimulation blockade with belatacept) offer potential for enhanced benefits.

Machine Learning for the Prediction of Red Blood Cell Transfusion in Patients During or After Liver Transplantation Surgery

Aim: This study aimed to use machine learning algorithms to identify critical preoperative variables and predict the red blood cell (RBC) transfusion during or after liver transplantation surgery. Study Design and Methods: A total of 1,193 patients undergoing liver transplantation in three large tertiary hospitals in China were examined. Twenty-four preoperative variables were collected, including essential population characteristics, diagnosis, symptoms, and laboratory parameters. The cohort was randomly split into a train set (70%) and a validation set (30%). The Recursive Feature Elimination and eXtreme Gradient Boosting algorithms (XGBOOST) were used to select variables and build machine learning prediction models, respectively. Besides, seven other machine learning models and logistic regression were developed. The area under the receiver operating characteristic (AUROC) was used to compare the prediction performance of different models. The SHapley Additive exPlanations package was applied to interpret the XGBOOST model. Data from 31 patients at one of the hospitals were prospectively collected for model validation. Results: In this study, 72.1% of patients in the training set and 73.2% in the validation set underwent RBC transfusion during or after the surgery. Nine vital preoperative variables were finally selected, including the presence of portal hypertension, age, hemoglobin, diagnosis, direct bilirubin, activated partial thromboplastin time, globulin, aspartate aminotransferase, and alanine aminotransferase. The XGBOOST model presented significantly better predictive performance (AUROC: 0.813) than other models and also performed well in the prospective dataset (accuracy: 76.9%). Discussion: A model for predicting RBC transfusion during or after liver transplantation was successfully developed using a machine learning algorithm based on nine preoperative variables, which could guide high-risk patients to take appropriate preventive measures.

Effect of remote ischemic preconditioning among donors and recipients following pediatric liver transplantation: A randomized clinical trial

BACKGROUND

Studies suggested that remote ischemic preconditioning (RIPC) may effectively lessen the harmful effects of ischemia reperfusion injury during organ transplantation surgery.

AIM

To investigate the protective effects of RIPC on living liver donors and recipients following pediatric liver transplantation.

METHODS

From January 2016 to January 2019 at Renji Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, 208 donors were recruited and randomly assigned to four groups: S-RIPC group (no intervention; n = 55), D-RIPC group (donors received RIPC; n = 51), R-RIPC group (recipients received RIPC, n = 51) and DR-RIPC group (both donors and recipients received RIPC; n = 51). We primarily evaluated postoperative liver function among donors and recipients and incidences of early allograft dysfunction, primary nonfunction and postoperative complications among recipients.

RESULTS

RIPC did not significantly improve alanine transaminase and aspartate aminotransferase levels among donors and recipients or decrease the incidences of early allograft dysfunction, primary nonfunction, and postoperative complications among recipients. Limited protective effects were observed, including a lower creatinine level in the D-RIPC group than in the S-RIPC group on postoperative day 0 (P < 0.05). However, no significant improvements were found in donors who received RIPC. Furthermore, RIPC had no effects on the overall survival of recipients.

CONCLUSION

The protective effects of RIPC were limited for recipients who received living liver transplantation, and no significant improvement of the prognosis was observed in recipients.

Assessment of Anastomotic Biliary Complications in Adult Patients Undergoing High-Acuity Liver Transplant

Importance

Anastomotic biliary complications (ABCs) constitute the most common technical complications in liver transplant (LT). Given the ever-increasing acuity of LT, identification of factors contributing to ABCs is essential to minimize morbidity and optimize outcomes. A detailed analysis in a patient population undergoing high-acuity LT is lacking.

Objective

To evaluate the rate of, risk factors for, and outcomes of ABCs and acuity level in LT recipients.

Design, Setting, and Participants

This retrospective cohort study included adult LT recipients from January 1, 2013, through June 30, 2016, at a single large urban transplant center. Patients were followed up for at least 12 months after LT until June 30, 2017. Of 520 consecutive adult patients undergoing LT, 509 LTs in 503 patients were included. Data were analyzed from May 1 through September 13, 2017.

Exposure

Liver transplant.

Main Outcomes and Measures

Any complications occurring at the level of the biliary reconstruction.

Results

Among the 503 transplant recipients undergoing 509 LTs included in the analysis (62.3% male; median age, 58 years [interquartile range {IQR}, 50-63 years), median follow-up was 24 months (IQR, 16-34 months). Overall patient and graft survival at 1 year were 91.1% and 90.3%, respectively. The median Model for End-stage Liver Disease (MELD) score was 35 (IQR, 15-40) for the entire cohort. T tubes were used in 199 LTs (39.1%) during initial bile duct reconstruction. Overall incidence of ABCs included 103 LTs (20.2%). Anastomotic leak occurred in 25 LTs (4.9%) and stricture, 77 (15.1%). Exit-site leak in T tubes occurred in 36 (7.1%) and T tube obstruction in 16 (3.1%). Seventeen patients with ABCs required surgical revision of bile duct reconstruction. Multivariate analysis revealed the following 7 independent risk factors for ABCs: recipient hepatic artery thrombosis (odds ratio [OR], 12.41; 95% CI, 2.37-64.87; P = .003), second LT (OR, 4.05; 95% CI, 1.13-14.50; P = .03), recipient hepatic artery stenosis (OR, 3.81; 95% CI, 1.30-11.17; P = .02), donor hypertension (OR, 2.79; 95% CI, 1.27-6.11; P = .01), recipients with hepatocellular carcinoma (OR, 2.66; 95% CI, 1.23-5.74; P = .01), donor death due to anoxia (OR, 2.61; 95% CI, 1.13-6.03; P = .03), and use of nonabsorbable suture material for biliary reconstruction (OR, 2.45; 95% CI, 1.09-5.54; P = .03).

Conclusions and Relevance

This large, single-center series identified physiologic and anatomical independent risk factors contributing to ABCs after high-acuity LT. Careful consideration of these factors could guide perioperative management and mitigate potentially preventable ABCs.

New Perspectives in Liver Transplantation: From Regeneration to Bioengineering

Advanced liver diseases have very high morbidity and mortality due to associated complications, and liver transplantation represents the only current therapeutic option. However, due to worldwide donor shortages, new alternative approaches are mandatory for such patients. Regenerative medicine could be the more appropriate answer to this need. Advances in knowledge of physiology of liver regeneration, stem cells, and 3D scaffolds for tissue engineering have accelerated the race towards efficient therapies for liver failure. In this review, we propose an update on liver regeneration, cell-based regenerative medicine and bioengineering alternatives to liver transplantation.

Technical Aspects of Orthotopic Liver Transplantation-a Survey-Based Study Within the Eurotransplant, Swisstransplant, Scandiatransplant, and British Transplantation Society Networks

BACKGROUND

Orthotopic liver transplantation (OLT) has emerged as the mainstay of treatment for end-stage liver disease. However, technical aspects of OLT are still subject of ongoing debate and are widely based on personal experience and local institutional protocols.

METHODS

An international online survey was sent out to all liver transplant centers (n = 52) within the Eurotransplant, Swisstransplant, Scandiatransplant, and British Transplant Society networks. The survey sought information on center-specific OLT caseload, vascular and biliary reconstruction, graft reperfusion, intraoperative control of hemodynamics, and drain policies.

RESULTS

Forty-two centers gave a valid response (81%). Out of these, 50% reported piggy-back and 40.5% total caval replacement as their standard technique. While 48% of all centers generally do not apply veno-venous bypass (vvBP) or temporary portocaval shunt (PCS) during OLT, vvBP/PCS are routinely used in six centers (14%). Portal vein first reperfusion is used in 64%, followed by simultaneous (17%), and retrograde reperfusion (12%). End-to-end duct-to-duct anastomosis without biliary drain (67%) is the most frequently performed method of biliary reconstruction. No significant associations were found between the center caseload and the surgical approach used. The predominant part of the centers (88%) stated that techniques of OLT are not evidence-based and 98% would participate in multicenter clinical trials on these topics.

CONCLUSION

Technical aspects of OLT vary widely among European centers. The extent to which center-specific variation of techniques affect transplant outcomes in Europe should be elucidated further in prospective multicenter trials.

Biochemical Markers for the Diagnosis and Monitoring of Wilson Disease

Wilson disease (WD) is an autosomal recessively-inherited disorder of copper metabolism and characterised by a pathological accumulation of copper. The ATP7B gene encodes for a transmembrane copper transporter essential for biliary copper excretion. Depending on time of diagnosis, severity of disease can vary widely. Almost all patients show evidence of progressive liver disease. Neurological impairments or psychiatric symptoms are common in WD patients not diagnosed during adolescence. WD is a treatable disorder, and early treatment can prevent the development of symptoms in patients diagnosed while still asymptomatic. This is why the early diagnosis of WD is crucial. The diagnosis is based on clinical symptoms, abnormal measures of copper metabolism and DNA analysis. Available treatment includes chelators and zinc salts which increase copper excretion and reduce copper uptake. In severe cases, liver transplantation is indicated and accomplishes a phenotypic correction of the hepatic gene defect. Recently, clinical development of the new copper modulating agent tetrathiomolybdate has started and direct genetic therapies are being tested in animal models. The following review focuses especially on biochemical markers and how they can be utilised in diagnosis and drug monitoring.

Implementing an innovated preservation technology: The American Society of Transplant Surgeons' (ASTS) Standards Committee White Paper on Ex Situ Liver Machine Perfusion

The pervasive shortage of deceased donor liver allografts contributes to significant waitlist mortality despite efforts to increase organ donation. Ex vivo liver perfusion appears to enhance preservation of donor organs, extending viability and potentially evaluating function in organs previously considered too high risk for transplant. These devices pose novel challenges for organ allocation, safety, training, and finances. This white paper describes the American Society of Transplant Surgeons' belief that organ preservation technology is a vital advance, but its use should not change fundamental aspects of organ allocation. Additional data elements need to be collected, made available for organ assessment by transplant professionals to allow determination of organ suitability in the case of reallocation and incorporated into risk adjustment methodology. Finally, further work is needed to determine the optimal strategy for management and oversight of perfused organs prior to transplantation.

Liver ex situ machine perfusion preservation: A review of the methodology and results of large animal studies and clinical trials

Ex vivo machine perfusion (MP) is a promising way to better preserve livers prior to transplantation. Currently, no methodology has a verified benefit over simple cold storage. Before becoming clinically feasible, MP requires validation in models that reliably predict human performance. Such a model has been found in porcine liver, whose physiological, anatomical, and immunological characteristics closely resemble the human liver. Since the 1930s, researchers have explored MP as preservation, but only recently have clinical trials been performed. Making this technology clinically available holds the promise of expanding the donor pool through more effective preservation of extended criteria donor (ECD) livers. MP promises to decrease delayed graft function, primary nonfunction, and biliary strictures, which are all common failure modes of transplanted ECD livers. Although hypothermic machine perfusion (HMP) has become the standard for kidney ex vivo preservation, the precise settings and clinical role for liver MP have not yet been established. In research, there are 2 schools of thought: normothermic machine perfusion, closely mimicking physiologic conditions, and HMP, to maximize preservation. Here, we review the literature for porcine ex vivo MP, with an aim to summarize perfusion settings and outcomes pertinent to the clinical establishment of MP. Liver Transplantation 23 679-695 2017 AASLD.

New insights after the first 1000 liver transplantations at The University of Hong Kong

BACKGROUND/OBJECTIVE

One thousand liver transplantations have been performed at the only liver transplant center in Hong Kong over a period of 22 years, which covered the formative period of living donor liver transplantation. These 1000 transplantations, which marked the journey of liver transplantation from development to maturation at the center, should be educational. This research was to study the experience and to reflect on the importance of technical innovations and case selection.

METHODS

The first 1000 liver transplantations were studied. Key technical innovations and surgical therapeutics were described. Recipient survival including hospital mortality was analyzed. Recipient survival comparison was made for deceased donor liver transplantation and living donor liver transplantation indicated by hepatocellular carcinoma and other diseases.

RESULTS

Among the 1000 transplantations, 418 used deceased donor grafts and 582 used living donor grafts. With the accumulation of experience, hospital mortality improved to < 2% in the past 2 years. In the treatment of diseases other than hepatocellular carcinoma, living donor liver transplantation was superior to deceased donor liver transplantation, with a 10-year recipient survival around 90%.

CONCLUSION

Transplant outcomes have been improving consistently over the series, with a very low hospital mortality and a predictably high long-term survival.

Normothermic perfusion machine in liver transplant with cardiac death donor grafts

The increasing difference between the number of patients in waiting lists for liver transplantation and the number of available donors has generated a great interest in the use of non-ideal organs, like grafts obtained from cardiac death donors (DCD). However, the extreme sensibility to ischemia of these livers results in a low utilization rate and a high percentage of post-transplant complications and re-transplantation. Normothermic perfusion machines (NMP) emerged as an alternative that tries to maintain the viability of the organ and even to improve its function. This review focuses on current results of DCD liver transplantation and on the role that NMP may have in this field.

Rationale of personalized immunosuppressive medication for hepatocellular carcinoma patients after liver transplantation

Liver transplantation is the only potentially curative treatment for hepatocellular carcinoma (HCC) that is not eligible for surgical resection. However, disease recurrence is the main challenge to the success of this treatment. Immunosuppressants that are universally used after transplantation to prevent graft rejection could potentially have a significant impact on HCC recurrence. Nevertheless, current research is exclusively focused on mammalian target of rapamycin inhibitors, which are thought to be the only class of immunosuppressive agents that can reduce HCC recurrence. In fact, substantial evidence from the bench to the bedside indicates that other classes of immunosuppressants may also exert diverse effects; for example, inosine monophosphate dehydrogenase inhibitors potentially have antitumor effects. In this article, we aim to provide a comprehensive overview of the potential effects of different types of immunosuppressants on HCC recurrence and their mechanisms of action from both experimental and clinical perspectives. To ultimately improve the outcomes of HCC patients after transplantation, we propose a concept and approaches for developing personalized immunosuppressive medication to be used either as immunosuppression maintenance or during the prevention/treatment of HCC recurrence.

Ex vivo normothermic machine perfusion and viability testing of discarded human donor livers

In contrast to traditional static cold preservation of donor livers, normothermic machine perfusion may reduce preservation injury, improve graft viability and potentially allows ex vivo assessment of graft viability before transplantation. We have studied the feasibility of normothermic machine perfusion in four discarded human donor livers. Normothermic machine perfusion consisted of pressure and temperature controlled pulsatile perfusion of the hepatic artery and continuous portal perfusion for 6 h. Two hollow fiber membrane oxygenators provided oxygenation of the perfusion fluid. Biochemical markers in the perfusion fluid reflected minimal hepatic injury and improving function. Lactate levels decreased to normal values, reflecting active metabolism by the liver (mean lactate 10.0 ± 2.3 mmol/L at 30 min to 2.3 ± 1.2 mmol/L at 6 h). Bile production was observed throughout the 6 h perfusion period (mean rate 8.16 ± 0.65 g/h after the first hour). Histological examination before and after 6 h of perfusion showed well-preserved liver morphology without signs of additional hepatocellular ischemia, biliary injury or sinusoidal damage. In conclusion, this study shows that normothermic machine perfusion of human donor livers is technically feasible. It allows assessment of graft viability before transplantation, which opens new avenues for organ selection, therapeutic interventions and preconditioning.

Completely steroid-free immunosuppression in liver transplantation: a randomized study

INTRODUCTION

Corticosteroids (CS) have been standard immunosuppression to prevent and treat rejection. However, CS are associated with increased risk of infection, obesity, hypertension, hyperlipidemia, diabetes, and accelerated hepatitis C virus (HCV) recurrence post-orthotopic liver transplantation (OLT). This study assesses the safety and efficacy of CS-free immunosuppressive regimen in adult OLT.

METHODS

A two-yr, prospective, randomized study of CS with delayed withdrawal (CS) or CS-free regimen with basiliximab, tacrolimus, and enteric-coated mycophenolate sodium (EC-MPS) was performed in 39 patients (CS=20; CS-free=19). CS group received intra-operative methylprednisolone weaned by six months. HCV patients had HCV PCR pre-OLT and 0.5, one, three, and six months post-OLT. Protocol liver biopsies were performed at OLT, 2 and 24 wk post-OLT or when indicated.

RESULTS

Rejection occurred in two patients. Patient survival at one yr (100% vs. 95%), three yr (85% vs. 63%), and five yr (80% vs. 63%) post-OLT were similar between CS and CS-free group, respectively. Death-censored graft survival at one yr (100% vs. 95%), three yr (85% vs. 63%), and five yr (75% vs. 63%) were also similar. The risk of new-onset DM, hypertension, hypercholesterolemia, and weight gain was similar between groups.

CONCLUSION

CS avoidance with basiliximab, calcineurin inhibitor, and EC-MPS is safe and effective as CS- containing immunosuppression in adult OLT.

Donation after cardiac death: where, when, and how?

The continuing shortage of donors has led to the increasing use of marginal grafts. Surgical techniques such as split, domino, and living donations have not been able to decrease waiting list mortality. Donation after cardiac death (DCD) was the only source of grafts prior to the establishment of brain death criteria in 1968. Thereafter, donation after brain death emerged as the leading source of grafts. The context in which irreversible cessation of circulatory and respiratory functions happens was the cornerstone to definite the four categories of DCD by the First International Workshop on DCD held in Maastricht in 1995. Controlled (CDCD) and uncontrolled (UDCD) categories now account for 10%-20% of the donor pool in several countries. Despite initial high rates of primary nonfunction and ischemic-type biliary lesions, refinements in protocols and surgical techniques have led to excellent 1- and 3-year graft survivals of 80% and 70%, respectively with PNF and ITBL rates below 3%. The institution of UDCD and CDCD depends on legal considerations of presumed consent and withdrawal of maneuvers, respectively. The potential for DCD programs is huge; it may be the only real, effective way to increase the grafts pool, both in adult and pediatric populations. Recent advances in perfusion machines will surely optimize this donor pool and allow new therapies for graft resuscitation.

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.

Cell therapies for liver diseases

Cell therapies, which include bioartificial liver support and hepatocyte transplantation, have emerged as potential treatments for a variety of liver diseases. Acute liver failure, acute-on-chronic liver failure, and inherited metabolic liver diseases are examples of liver diseases that have been successfully treated with cell therapies at centers around the world. Cell therapies also have the potential to be widely applied to other liver diseases, including noninherited liver diseases and liver cancer, and to improve the success of liver transplantation. Here we briefly summarize current concepts of cell therapy for liver diseases.

Impact of steroids on hepatitis C virus replication in vivo and in vitro

Chronic hepatitis C virus (HCV) infection is the leading indication for liver transplantation. Transplantation outcome is often compromised by a rapid re-infection of the graft. Several factors have been implicated in the increased severity of recurrence, including steroid-based immunosuppression. Evidence suggests that steroid boluses used to treat acute rejection are associated with an increase in HCV viral load and the severity of recurrence. Two possible mechanisms for a steroid-mediated effect on HCV viral loads can be postulated, the first being a direct effect of steroids on the virus by enhancing its replication. The second, an indirect effect due to the suppression of the HCV immune response, allows unrestricted HCV replication. To investigate the direct effect of steroids on HCV replication, dexamethasone (Dex) and prednisolone (Pred) were tested in an in vitro replicon model. HCV replication was assessed on the basis of luciferase reporter expression (luminescence) and HCV RNA (RT-PCR). At clinically relevant concentrations (1-10 nM), treatment with both Dex and Pred did not enhance, but resulted in a slight reduction of relative luciferase activity (HCV replication), which was independent of increased cellular protein content and reduced cell proliferation. This minor reduction of HCV replication was confirmed by RT-PCR showing more than 41% reduction in HCV RNA levels. In conclusion, despite clinical evidence that the use of steroids aggravates recurrence of HCV, our in vitro study suggests that there is no direct stimulatory effect of steroids on the replication of HCV. As such, the increased viral loads after high-dose steroid treatment are more likely due to a downregulation of the immune response. In such patients, a dampened immune response allows viruses like HCV to replicate free of immune-mediated killing of their host cells. When a change occurs, such as a tapering or an alteration of immunosuppressant drugs, the immune system reinitiates and vigorously attempts to control the virus, resulting in acceleration of liver damage. Therefore, either steroid avoidance or maintaining low levels, coupled with a slow tapering of corticosteroids, may be beneficial to HCV-infected transplantation recipients.

Operative mortality after renal transplantation--does surgeon type matter?

PURPOSE

Currently there are 64 accredited renal transplantation fellowships in Canada and the United States. Only 27% are limited in scope to kidney transplants. In the remaining fellowships the trainee learns to transplant multiple abdominal organs. Given this evolution to the multiorgan transplant surgeon, we evaluated the effect of the current training paradigm on practice patterns and outcomes for kidney transplants.

MATERIALS AND METHODS

Using data from the Nationwide Inpatient Sample, discharge records for kidney transplants (6,674) were abstracted (1993 to 2003). Through the Nationwide Inpatient Sample unique surgeon identifier we determined the proportion of kidney transplants performed by multiorgan and kidney only transplant surgeons. We fit multilevel regression models to examine the relationship between surgeon type and transplant outcome.

RESULTS

We identified 99 multiorgan and 196 kidney only transplant surgeons who performed 3,255 and 3,419 kidney transplants, respectively. Kidney only transplant surgeons were more likely than multiorgan surgeons to practice in nonteaching, private, for-profit hospitals (p <0.05). Unadjusted operative mortality was higher in patients treated by kidney only vs multiorgan transplant surgeons (1.7% vs 0.9%, p = 0.002). After adjusting for patient and hospital factors, those who underwent renal transplantation performed by multiorgan transplant surgeons had 55% lower odds of inpatient death (OR 0.45, 95% CI 0.26-0.76) vs kidney only transplant surgeons.

CONCLUSIONS

Despite the current training paradigm, kidney only transplant surgeons have a prominent role in renal transplantation. However, given the current donor organ shortage and the implications for quality, the observed mortality difference suggests that additional investigation is needed to determine whether this role should be decreased.

[Intensive care treatment following transplant surgery]

Transplant-related intensive care treatment after transplantation of visceral organs, in Germany traditionally headed by transplant surgeons, is an integral part of postoperative therapy after liver, pancreas, intestinal, and combined organ transplantation, i.e. pancreas-kidney, liver-kidney, and multivisceral transplantation. Apart from adjustment and monitoring of immunosuppressive therapy, as well as common intensive care issues such as cardiopulmonary disease and complications, the avoidance, early detection, and rigorous treatment of transplant-related problems are the focus of surgical intensive care treatment of transplant patients. In the following article, its role after visceral organ transplantation is described regarding the most frequent transplant-related complications such as technical failure, various kinds of infection, and graft failure with different etiologies.

Donation after cardiac death as a strategy to increase deceased donor liver availability

OBJECTIVE

This study examines donation after cardiac death (DCD) practices and outcomes in liver transplantation.

SUMMARY BACKGROUND DATA

Livers procured from DCD donors have recently been used to increase the number of deceased donors and bridge the gap between limited organ supply and the pool of waiting list candidates. Comprehensive evaluation of this practice and its outcomes has not been previously reported.

METHODS

A national cohort of all DCD and donation after brain-death (DBD) liver transplants between January 1, 2000 and December 31, 2004 was identified in the Scientific Registry of Transplant Recipients. Time to graft failure (including death) was modeled by Cox regression, adjusted for relevant donor and recipient characteristics.

RESULTS

DCD livers were used for 472 (2%) of 24,070 transplants. Annual DCD liver activity increased from 39 in 2000 to 176 in 2004. The adjusted relative risk of DCD graft failure was 85% higher than for DBD grafts (relative risk, 1.85; 95% confidence interval, 1.51-2.26; P < 0.001), corresponding to 3-month, 1-year, and 3-year graft survival rates of 83.0%, 70.1%, and 60.5%, respectively (vs. 89.2%, 83.0%, and 75.0% for DBD recipients). There was no significant association between transplant program DCD liver transplant volume and graft outcome.

CONCLUSIONS

The annual number of DCD livers used for transplant has increased rapidly. However, DCD livers are associated with a significantly increased risk of graft failure unrelated to modifiable donor or recipient factors. Appropriate recipients for DCD livers have not been fully characterized and recipient informed consent should be obtained before use of these organs.

Donation after cardiac death as a strategy to increase deceased donor liver availability

OBJECTIVE

This study examines donation after cardiac death (DCD) practices and outcomes in liver transplantation.

SUMMARY BACKGROUND DATA

Livers procured from DCD donors have recently been used to increase the number of deceased donors and bridge the gap between limited organ supply and the pool of waiting list candidates. Comprehensive evaluation of this practice and its outcomes has not been previously reported.

METHODS

A national cohort of all DCD and donation after brain-death (DBD) liver transplants between January 1, 2000 and December 31, 2004 was identified in the Scientific Registry of Transplant Recipients. Time to graft failure (including death) was modeled by Cox regression, adjusted for relevant donor and recipient characteristics.

RESULTS

DCD livers were used for 472 (2%) of 24,070 transplants. Annual DCD liver activity increased from 39 in 2000 to 176 in 2004. The adjusted relative risk of DCD graft failure was 85% higher than for DBD grafts (relative risk, 1.85; 95% confidence interval, 1.51-2.26; P < 0.001), corresponding to 3-month, 1-year, and 3-year graft survival rates of 83.0%, 70.1%, and 60.5%, respectively (vs. 89.2%, 83.0%, and 75.0% for DBD recipients). There was no significant association between transplant program DCD liver transplant volume and graft outcome.

CONCLUSIONS

The annual number of DCD livers used for transplant has increased rapidly. However, DCD livers are associated with a significantly increased risk of graft failure unrelated to modifiable donor or recipient factors. Appropriate recipients for DCD livers have not been fully characterized and recipient informed consent should be obtained before use of these organs.

Predicted lifetimes for adult and pediatric split liver versus adult whole liver transplant recipients

Split liver transplantation allows 2 recipients to receive transplants from one organ. Comparisons of predicted lifetimes for two alternatives (split liver for an adult and pediatric recipient vs. whole liver for an adult recipient) can help guide the use of donor livers. We analyzed mortality risk for 48,888 waitlisted candidates, 907 split and 21,913 whole deceased donor liver transplant recipients between January 1, 1995 and February 26, 2002. Cox regression models for pediatric and adult patients assessed average relative wait list and post-transplant death risks, for split liver recipients. Life years gained compared with remaining on the waiting list over a 2-year period were calculated. Seventy-six splits (152 recipients) and 24 re-transplants resulted from every 100 livers (13.1% [adult] and 18.0% [pediatric] 2-year re-transplant rates, respectively). Whole livers used for 93 adults also utilized 100 livers (re-transplant rate 7.0%). Eleven extra life years and 59 incremental recipients accrued from each 100 livers used for split compared with whole organ transplants. Split liver transplantation could provide enough organs to satisfy the entire current demand for pediatric donor livers in the United States, provide more aggregate years of life than whole organ transplants and result in larger numbers of recipients.

The management of coagulopathy and blood loss in liver surgery

Liver surgery has long been associated with massive perioperative blood loss and high rates of postsurgery morbidity and mortality. Recent advances in our knowledge of hepatic segmental anatomy have led to the evolution of liver resection, and a growing awareness of the coagulopathy present in cirrhotic patients has produced a greater understanding of the factors influencing surgical hemostasis. This review will examine the risk factors for perioperative hemorrhage in liver disease patients, and will describe current pharmacological, surgical, and radiological methods available for controlling bleeding and achieving effective hemostasis during liver resection and orthotopic liver transplantation (OLT). The potential role of recombinant factor VIIa (rFVIIa) in providing safe hemostasis during such procedures will also be explored. Today, due to careful monitoring and correction of coagulopathy, improved surgical techniques, and judicious patient selection, liver surgery is no longer a high-risk specialty with an unfavorable risk profile, but a safe and widely practiced procedure.

Hepatic progenitors and strategies for liver cell therapies

Liver cell therapies, including liver cell transplantation and bioartificial livers, are being developed as alternatives to whole liver transplantation for some patients with severe liver dysfunction. Hepatic progenitors are proposed as ideal cells for use in these liver cell therapies given their ability to expand extensively, differentiate into all mature liver cells, have minimal immunogenicity, be cryopreservable, and reconstitute liver tissue when transplanted. We summarize our ongoing efforts to develop clinical programs of hepatic progenitor cell therapies with a focus on hepatic stem cell biology and strategies that have emerged in analyzing that biology.

Orthotopic hepatic transplantation in the dog

Orthotopic hepatic transplantation has become a well-established treatment modality for end-stage liver disease, and research in this field is constantly evolving. Of the 34 canine liver transplants performed in this study, 17 (50%) survived more than 3 days (mean survival time 15 days). Causes of perioperative death included hemorrhage (4), anesthetic complications (3), systemic anaphylaxis (3), portal vein thrombosis (3), hepatic venous outflow block (2), and hepatic artery thrombosis (2). Gentle handling with minimal dissection of the donor liver in situ resulted in a decreased incidence of hepatic venous outflow block. The incidence of biliary leak was similar irrespective of the method of biliary reconstruction, although the incidence of acute cholangitis was 56% in the cholecystoduodenostomy group compared with 0% in the choledochocholedochostomy cohort. Using celiac to common hepatic end-to-side arterial anastomosis with preservation of the gastroduodenal artery, thrombosis of the hepatic artery was encountered in four instances, an incidence similar to previously reported studies where end-to-end hepaticohepatic arterial anastomosis or donor aortic conduit was utilized. The incidence of postoperative intestinal intussusception was reduced from 40 to 0% in those who underwent transmesenteric intestinal plication following implantation of the liver. Among short-term survivors, sepsis was the most frequent noted complication (10), followed by intestinal intussusception (6), rejection (6), and gastrointestinal bleeding (1). Among recipient dogs that survived more than 3 days, rejection was the most common cause of graft loss (5), followed by biliary leak (4) and hepatic artery thrombosis (2).

Biliary tract reconstruction in liver transplantation

Biliary tract complications are often referred to as the "Achilles' heel" of liver transplantation and various techniques have been developed to overcome them. The two major methods of bile duct reconstruction currently in use consist of either (1) choledochocholedochostomy over a T-tube or, when duct-to-duct approximation is not feasible, choledochojejunostomy over an internal stent, or (2) interposition of the donor gallbladder as a conduit between the donor bile duct and either the recipient bile duct or a jejunal loop. Although these standardizations of biliary tract reconstruction have resulted in a reduction of biliary complications after liver transplantation, further advancement in the elucidation of ampullary obstruction and viability of the donor bile duct is needed.

Liver transplantation in man. I. Observations on technique and organization in five cases

In view of the extreme sensitivity of the human liver to ischaemic damage, the organization of clinical transplantation is of necessity complicated. From our preliminary experience of five human liver allografts we feel that active collaboration between hospitals is essential in order to practise human liver transplantation. It is unnecessary and undesirable to interfere in any way with potential liver donors. Nevertheless, the nature of the surgical technique requires that the liver is cooled within 15 minutes of death if satisfactory function is to result in the grafted organ.This report describes technical difficulties that were encountered which can limit successful liver transplantation. The first patient was in severe liver failure and had an accessory liver graft in the splenic fossa after splenectomy. This liver suffered irreversible ischaemic damage, which led to an uncontrollable haemorrhagic state with exsanguination that resulted in death the day after operation. The second patient, a 10-month-old infant with biliary atresia and liver failure, died from cardiac arrest shortly after the operation.The remaining three transplants developed good initial function. One patient survived 11 weeks, and one has returned to work.