The saga of liver replacement, with particular reference to the reciprocal influence of liver and kidney transplantation (1955-1967)

Liver Transplantation for Unresectable Colorectal Liver Metastasis: Perspective and Review of Current Literature

The treatment of unresectable colorectal liver metastasis (CRLM) has previously been limited to palliative chemotherapy. Traditionally, the role of liver transplant has not been associated with sufficient survival to justify a patient undergoing a major operation with the associated requirement for postoperative immunosuppression. With improvements in chemotherapy options, a certain subset of patients can experience stable disease for years, which has prompted investigation into the role of liver transplant in these patients. Several recent studies have shown promising results in well-selected patients, with posttransplant survival approaching that of liver transplant recipients for other diseases. Here, we present a review of the data and current protocols for liver transplant for unresectable CRLM.

SHock-INduced Endotheliopathy (SHINE): A mechanistic justification for viscoelastography-guided resuscitation of traumatic and non-traumatic shock

Irrespective of the reason for hypoperfusion, hypocoagulable and/or hyperfibrinolytic hemostatic aberrancies afflict up to one-quarter of critically ill patients in shock. Intensivists and traumatologists have embraced the concept of SHock-INduced Endotheliopathy (SHINE) as a foundational derangement in progressive shock wherein sympatho-adrenal activation may cause systemic endothelial injury. The pro-thrombotic endothelium lends to micro-thrombosis, enacting a cycle of worsening perfusion and increasing catecholamines, endothelial injury, de-endothelialization, and multiple organ failure. The hypocoagulable/hyperfibrinolytic hemostatic phenotype is thought to be driven by endothelial release of anti-thrombogenic mediators to the bloodstream and perivascular sympathetic nerve release of tissue plasminogen activator directly into the microvasculature. In the shock state, this hemostatic phenotype may be a counterbalancing, yet maladaptive, attempt to restore blood flow against a systemically pro-thrombotic endothelium and increased blood viscosity. We therefore review endothelial physiology with emphasis on glycocalyx function, unique biomarkers, and coagulofibrinolytic mediators, setting the stage for understanding the pathophysiology and hemostatic phenotypes of SHINE in various etiologies of shock. We propose that the hyperfibrinolytic phenotype is exemplified in progressive shock whether related to trauma-induced coagulopathy, sepsis-induced coagulopathy, or post-cardiac arrest syndrome-associated coagulopathy. Regardless of the initial insult, SHINE appears to be a catecholamine-driven entity which early in the disease course may manifest as hyper- or hypocoagulopathic and hyper- or hypofibrinolytic hemostatic imbalance. Moreover, these hemostatic derangements may rapidly evolve along the thrombohemorrhagic spectrum depending on the etiology, timing, and methods of resuscitation. Given the intricate hemochemical makeup and changes during these shock states, macroscopic whole blood tests of coagulative kinetics and clot strength serve as clinically useful and simple means for hemostasis phenotyping. We suggest that viscoelastic hemostatic assays such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are currently the most applicable clinical tools for assaying global hemostatic function-including fibrinolysis-to enable dynamic resuscitation with blood products and hemostatic adjuncts for those patients with thrombotic and/or hemorrhagic complications in shock states.

The Choice between Plasma-Based Common Coagulation Tests and Cell-Based Viscoelastic Tests in Monitoring Hemostatic Competence: Not an either-or Proposition

There has been a significant interest in the last decade in the use of viscoelastic tests (VETs) to determine the hemostatic competence of bleeding patients. Previously, common coagulation tests (CCTs) such as the prothrombin time (PT) and partial thromboplastin time (PTT) were used to assist in the guidance of blood component and hemostatic adjunctive therapy for these patients. However, the experience of decades of VET use in liver failure with transplantation, cardiac surgery, and trauma has now spread to obstetrical hemorrhage and congenital and acquired coagulopathies. Since CCTs measure only 5 to 10% of the lifespan of a clot, these assays have been found to be of limited use for acute surgical and medical conditions, whereby rapid results are required. However, there are medical indications for the PT/PTT that cannot be supplanted by VETs. Therefore, the choice of whether to use a CCT or a VET to guide blood component therapy or hemostatic adjunctive therapy may often require consideration of both methodologies. In this review, we provide examples of the relative indications for CCTs and VETs in monitoring hemostatic competence of bleeding patients.

Liver transplantation for colorectal secondaries: on the way to validation

PURPOSE OF REVIEW

Liver transplantation for nonresectable colorectal liver metastases (CRLMs) is an emerging field within transplant oncology. This review summarizes recent developments within this field.

RECENT FINDINGS

More stringent selection criteria can yield 5-year survival rates that are similar to conventional indications for liver transplantation. Response to chemotherapy, low carcinoembryonic antigen levels, limited tumor volume and stable disease with observation time exceeding 12 months are fundamental requirements in this context. Radiomic analysis of pre transplant PET/computed tomography scans to determine metabolic tumor volume (MTV) in the liver seems particularly promising with regards to prediction of a favorable tumor biology. MTV values below 70 cm3 are associated with excellent long-term survival after transplantation, whereas the MTV threshold for liver resection seem far smaller. Recent studies put into question whether technical nonresectability per se is a valid inclusion criterion for liver transplantation. In patients with high hepatic tumor burden, but otherwise favorable prognostic features as assessed by the Oslo score, liver transplantation could possibly give a clinically relevant survival benefit compared with liver resection.

SUMMARY

Liver transplantation is feasible treatment option in highly selected patients with nonresectable CRLMs. Robust and stringent selection criteria should be applied according to international consensus guidelines.

Thromboelastography for the Prevention of Perioperative Venous Thromboembolism in Orthopedics

We have reviewed a large number of relevant literature to determine the deficiencies of orthopedics in the diagnosis and prevention of venous thromboembolism（VTE）events during the perioperative period, and found that the TEG technology has been widely used after liver transplantation, which may make up for the deficiencies. This review expounds the detection principle and latest thromboelastography (TEG) development, and highlights the advantages of TEG over previous screening methods in diagnosing hypercoagulability. By analyzing the correlation and consistency between TEG and conventional coagulation test, reliable indexes for diagnosing hypercoagulability and important parameters for guiding perioperative anticoagulation treatment were summarized. Furthermore, our work contributes to further studies of TEG in orthopedics. Based on the research results, we believe that TEG may help orthopedists to identify and predict VTE events, use anticoagulants, eventually reduce the occurrence of VTE events.

Viscoelastic Hemostatic Assays: A Primer on Legacy and New Generation Devices

Viscoelastic hemostatic assay (VHAs) are whole blood point-of-care tests that have become an essential method for assaying hemostatic competence in liver transplantation, cardiac surgery, and most recently, trauma surgery involving hemorrhagic shock. It has taken more than three-quarters of a century of research and clinical application for this technology to become mainstream in these three clinical areas. Within the last decade, the cup and pin legacy devices, such as thromboelastography (TEG^® 5000) and rotational thromboelastometry (ROTEM^® delta), have been supplanted not only by cartridge systems (TEG^® 6S and ROTEM^® sigma), but also by more portable point-of-care bedside testing iterations of these legacy devices (e.g., Sonoclot^®, Quantra^®, and ClotPro^®). Here, the legacy and new generation VHAs are compared on the basis of their unique hemostatic parameters that define contributions of coagulation factors, fibrinogen/fibrin, platelets, and clot lysis as related to the lifespan of a clot. In conclusion, we offer a brief discussion on the meteoric adoption of VHAs across the medical and surgical specialties to address COVID-19-associated coagulopathy.

Role of liver transplantation in the management of colorectal liver metastases: Challenges and opportunities

The liver is the most common site of colorectal cancer metastasis. Complete resection of the metastatic tumor is currently the only treatment modality available with a potential for cure. However, only 20% of colorectal liver metastases (CRLM) are considered resectable at the time of presentation. Liver transplantation (LT) has been proposed as an alternative oncologic treatment for patients with unresectable CRLM. This review summarizes the published experiences of LT in the setting of unresectable CRLM from the previous decades and discusses the challenges and future horizons in the field. Contemporary experiences that come mostly from countries with broader access to liver grafts are also explored and their promising findings in terms of overall survival (OS) and disease-free survival (DFS) are outlined along with their study design and methods. The rationale of establishing specific patient selection criteria and the dilemmas around immunosuppressive regimens in patients undergoing LT for CRLM are also highlighted. Additionally, this review describes the findings of studies comparing LT vs chemotherapy alone and LT vs portal vein embolization plus resection for CRLM in terms of OS and DFS. Last but not least, we present current perspectives and ongoing prospective trials that try to elucidate the role of LT for CRLM.

Liver transplantation for non-resectable colorectal liver metastases: the International Hepato-Pancreato-Biliary Association consensus guidelines

Colorectal cancer is a prevalent disease worldwide, with more than 50% of patients developing metastases to the liver. Despite advances in improving resectability, most patients present with non-resectable colorectal liver metastases requiring palliative systemic therapy and locoregional disease control strategies. There is a growing interest in the use of liver transplantation to treat non-resectable colorectal liver metastases in well selected patients, leading to a surge in the number of studies and prospective trials worldwide, thereby fuelling the emerging field of transplant oncology. The interdisciplinary nature of this field requires domain-specific evidence and expertise to be drawn from multiple clinical specialities and the basic sciences. Importantly, the wider societal implication of liver transplantation for non-resectable colorectal liver metastases, such as the effect on the allocation of resources and national transplant waitlists, should be considered. To address the urgent need for a consensus approach, the International Hepato-Pancreato-Biliary Association commissioned the Liver Transplantation for Colorectal liver Metastases 2021 working group, consisting of international leaders in the areas of hepatobiliary surgery, colorectal oncology, liver transplantation, hepatology, and bioethics. The aim of this study was to standardise nomenclature and define management principles in five key domains: patient selection, evaluation of biological behaviour, graft selection, recipient considerations, and outcomes. An extensive literature review was done within the five domains identified. Between November, 2020, and January, 2021, a three-step modified Delphi consensus process was undertaken by the workgroup, who were further subgrouped into the Scientific Committee, Expert Panel, and Transplant Centre Representatives. A final consensus of 44 statements, standardised nomenclature, and a practical management algorithm is presented. Specific criteria for clinico-patho-radiological assessments with molecular profiling is crucial in this setting. After this, the careful evaluation of biological behaviour with bridging therapy to transplantation with an appropriate assessment of the response is required. The sequencing of treatment in synchronous metastatic disease requires special consideration and is highlighted here. Some ethical dilemmas within organ allocation for malignant indications are discussed and the role for extended criteria grafts, living donor transplantation, and machine perfusion technologies for non-resectable colorectal liver metastases are reviewed. Appropriate immunosuppressive regimens and strategies for the follow-up and treatment of recurrent disease are proposed. This consensus guideline provides a framework by which liver transplantation for non-resectable colorectal liver metastases might be safely instituted and is a meaningful step towards future evidenced-based practice for better patient selection and organ allocation to improve the survival for patients with this disease.

The Transition to Microsurgical Technique for Hepatic Artery Reconstruction in Pediatric Liver Transplantation

BACKGROUND

Hepatic artery thrombosis represents a potentially fatal complication following liver transplantation. Rates of hepatic artery thrombosis are significantly higher in children, with mortality reported up to 80 percent. Microsurgical anastomosis has been shown to decrease the rate of hepatic artery thrombosis and now represents the standard of care at the authors' institution. In this article, the authors present the largest study of its type directly comparing rates of hepatic artery thrombosis with and without microsurgical reconstruction of the hepatic artery.

METHODS

All pediatric patients who underwent primary orthotopic liver transplantation between 1989 and 2018 were included. Patients were divided into two cohorts: standard anastomosis with loupes, and microsurgical anastomosis under the operating microscope. The authors' primary outcome was the rate of hepatic artery thrombosis. Secondary outcomes were graft survival, patient survival, retransplantation rate, requirement for intraoperative blood products, and length of stay.

RESULTS

Two hundred thirty-one children met criteria for inclusion. One hundred eighty cases were performed with loupe magnification and 51 cases were performed under the microscope. The hepatic artery thrombosis rate was lower, but not significantly so (p = 0.114), in the microsurgical group [n = 1 (2.0 percent)] compared with the standard cohort [n = 15 (8.3 percent)]. Survival analysis revealed a significant increase in graft survival with microsurgical anastomosis (p = 0.020), but not patient survival (p = 0.196). The retransplantation rate was significantly lower with microsurgical anastomosis (p = 0.021).

CONCLUSIONS

Microsurgical anastomosis was associated with a clinically important decrease in hepatic artery thrombosis compared with standard loupe anastomosis. The graft survival rate was significantly higher in the microsurgical cohort, with a reduced retransplantation rate at 1 year. On this basis, the authors recommend microsurgical hepatic artery anastomosis in cases of pediatric liver transplantation. .

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Expanding Donor Selection and Recipient Indications for Living Donor Liver Transplantation

There is an acute shortage of deceased donor organs for liver transplantation in the United States. Nearly a third of patients either die or become too sick for transplant while on the transplant waitlist. Living donor liver transplantation (LDLT) bridges the gap between demand and supply of organs for liver transplantation. This article reviews current living donor selection criteria, and avenues for expansion of criteria with novel surgical techniques and ongoing outcomes research. Ways in which institutions can establish and expand LDLT programs using the Living Donor Champion model are discussed. Efforts to expand recipient indications for LDLT are described.

Liver transplantation for secondary liver tumours: The difficult balance between survival and recurrence

Assessing the balance between survival and recurrence after transplantation for secondary liver tumours should be based on the type of cancer in question. For neuroendocrine liver metastases, high recurrence rates are clearly related to reduced long-term survival. For colorectal liver metastases, experience to date indicates that pulmonary recurrence alone has a modest impact on survival outcomes. Further studies focusing on this group of patients will be important for the development of this field of transplant oncology. Liver transplantation for secondary liver tumours should be implemented in accordance with stringent transplant criteria and preferably in the context of prospective trials. Expansion of the donor pool by utilising extended criteria donors and partial liver transplantation could be considered for this indication.

Hematopoietic Stem Cells and Their Roles in Tissue Regeneration

Hematopoietic stem cells (HSCs) are regarded as one of essential cell sources for treating regenerative diseases. Among many stem cells, the feasibility of using adult-derived hematopoietic stem cells in therapeutic approaches is very diverse, and is unarguably regarded as an important cell source in stem cell biology. So far, many investigators are exploring HSCs and modified HSCs for use in clinical and basic science. In the present review, we briefly summarized HSCs and their application in pathophysiologic conditions, including non-hematopoietic tissue regeneration as well as blood disorders. HSCs and HSCs-derived progenitors are promising cell sources in regenerative medicine and their contributions can be properly applied to treat pathophysiologic conditions. Among many adult stem cells, HSCs are a powerful tool to treat patients with diseases such as hematologic malignancies and liver disease. Since HSCs can be differentiated into diverse progenitors including endothelial progenitors, they may be useful for constructing strategies for effective therapy.

Comparison between liver transplantation and resection for hilar cholangiocarcinoma: A systematic review and meta-analysis

BACKGROUND

Hilar cholangiocarcinoma (hCCA) is a rare and aggressive malignancy with R0 resection being currently the only option for long-term survival. With the improvement in the outcomes of liver transplantation (LT), the indications for LT have expanded to include other malignant tumors, such as hCCA. The aim of the present analysis is to demonstrate and critically evaluate the outcomes of LT compared to resection with curative intent in patients with hCCA.

METHODS

We systematically searched the literature for articles published up to May 2018. The following algorithm was applied ((hilar cholangiocarcinoma) OR (perihilar cholangiocarcinoma) OR klatskin$ OR (bile duct neoplasm) OR cholangiocarcinoma) AND (transplant$ OR graft$).

RESULTS

Neoadjuvant treatment with chemotherapy and radiation therapy was far more common in the LT group, with very few patients having received preoperative therapy in the resection group (p = 0.0005). Moreover, length of hospital stay was shorter after LT than after resection (p<0.00001). In contrast, no difference was found between the two treatment methods concerning postoperative mortality (p = 0.57). There was a trend towards longer overall survival after LT in comparison with resection. This was not obvious in the first year postoperatively, however, the advantage of LT over resection became obvious at 3 years after the operation (p = 0.02).

CONCLUSIONS

In non-disseminated unresectable tumors, LT seems to have a non-inferior survival. In the same patients, neoadjuvant chemoradiotherapy and/or strict selection criteria may contribute to superior survival outcomes compared to curative-intent resection. Due to the scarcity of level 1 evidence, it remains unclear whether LT should be increasingly considered for technically resectable early stage hCCA.

Liver transplantation in patients with liver metastases from neuroendocrine tumors

The prevalence of metastatic disease in neuroendocrine tumors (NETs) is very high (60-80%) and cancer-related death among these patients is generally due to metastatic disease. Numerous treatment options for cure and disease control have been investigated for patients with neuroendocrine liver metastases (NELM). Despite the success of liver directed therapy on slowing tumor progression and palliating symptoms, the chance of being cured by liver resection is 40-50% and only roughly 20% of patients have potentially resectable disease. As such, there has been interest in liver transplantation (LT) as a potentially curative option for patients with unresectable disease. Several criteria have been proposed in order to balance long-term outcomes of patients with NELM and the problem of organ shortage including the Milan-NET criteria, the UNOS criteria and the ENETS guidelines. In the most representative studies, recurrence rate after LT has ranged from 30% to 60% with a 5-year OS ranging from 50% to 97%. This large variability is due to the retrospective nature of the studies available, which used different inclusion criteria. As such, outcomes and the prognostic factors associated with LT for NELM warrant further investigation.

Use of Viscoelastography in Malignancy-Associated Coagulopathy and Thrombosis: A Review

The relationship between malignancy and coagulopathy is one that is well documented yet incompletely understood. Clinicians have attempted to quantify the hypercoagulable state produced in various malignancies using common coagulation tests such as prothrombin time, activated partial thromboplastin time, and platelet count; however, due to these tests' focus on individual aspects of coagulation during one specific time point, they have failed to provide clinicians the complete picture of malignancy-associated coagulopathy (MAC). Viscoelastic tests (VETs), such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM), are whole blood analyses that have the advantage of providing information related to the cumulative effects of plasma clotting factors, platelets, leukocytes, and red cells during all stages of the coagulation and fibrinolytic processes. VETs have gained popularity in the care of trauma patients to objectively measure trauma-induced coagulopathy (TIC), but the utility of VETs remains yet unrealized in many other medical specialties. The authors discuss the similarities and differences between TIC and MAC, and propose a mechanism for the hypercoagulable state of MAC that revolves around the thrombomodulin-thrombin complex as it switches between activating the protein C anticoagulation pathway or the thrombin activatable fibrinolysis inhibitor coagulation pathway. Additionally, they review the current literature on the use of TEG and ROTEM in patients with various malignancies. Although limited research is currently available, early results demonstrate the utility of both TEG and ROTEM in the prediction of hypercoagulable states and thromboembolic complications in oncologic patients.

Pretreatment neutrophil-lymphocyte ratio: useful prognostic biomarker in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common liver malignancy and the third most common cause of cancer-related deaths. Liver resection (LR) and liver transplantation (LT) are the only curative modalities for HCC. Despite recent advances and the adoption of the Milan and University of California, San Francisco, criteria, HCC recurrence after LR and LT remains a challenge. Several markers and prognostic scores have been proposed to predict tumor aggressiveness and supplement radiological data; among them, neutrophil–lymphocyte ratio (NLR) has recently gained significant interest. An elevated NLR is thought to predispose to HCC recurrence by creating a protumorigenic microenvironment through both relative neutrophilia and lymphocytopenia. In the present review, we attempted to summarize the published work on the role of pretreatment NLR as a prognostic marker for HCC following LR and LT. A total of 13 LT and 18 LR studies were included from 2008 to 2015. Pretransplant NLR was most often predictive of HCC recurrence, recurrence-free survival, and overall survival. NLR was, however, more variably and less clearly associated with worse outcomes following LR.

The Potential Role of Liver Transplantation as a Treatment Option in Colorectal Liver Metastases

Liver resection is the only potentially curative treatment option in patients with liver metastases from colorectal cancer, but only about 20% of the patients are resectable. Liver transplantation of patients with unresectable liver metastases was attempted in the early era but it was abandoned due to poor survival. During the last decade, several case reports, a controlled pilot study, and a retrospective cohort study indicated that prolonged disease-free survival and overall survival can be obtained in a proportion of these patients. Strict selection criteria have not yet been well defined, but tumor load, response to chemotherapy, pretransplant carcinoembryonic antigen level, and time interval from resection of the primary tumor to transplant are all factors related to outcome. Carefully selected patients may obtain 5-year overall survival that approaches conventional indications for liver transplant. The scarcity of liver grafts is a significant problem, but this can possibly to some extent be addressed by use of extended criteria grafts and novel surgical techniques. There is an increasing interest in liver transplantation in these patients in the transplant community, and currently 4 clinical trials are active and are recruiting.

Liver transplantation for unresectable colorectal liver metastases: A systematic review

The use of liver transplantation (LT) for liver metastases attempted in the early 1990's was associated with poor perioperative outcomes and unacceptably low overall survival. Recently, there has been renewed interest in LT as a treatment option for colorectal liver metastases (CLM) in countries where organ supply is high. To date, no meticulous analysis about the efficacy, safety and outcomes of LT in CLM patients has been published. We present the first systematic review on the subject.

A novel prognostic nomogram accurately predicts hepatocellular carcinoma recurrence after liver transplantation: analysis of 865 consecutive liver transplant recipients

BACKGROUND

Although radiologic size criteria (Milan/University of California, San Francisco [UCSF]) have led to improved outcomes after liver transplantation (LT) for hepatocellular carcinoma (HCC), recurrence remains a significant challenge. We analyzed our 30-year experience with LT for HCC to identify predictors of recurrence.

STUDY DESIGN

A novel clinicopathologic risk score and prognostic nomogram predicting post-transplant HCC recurrence was developed from a multivariate competing-risk Cox regression analysis of 865 LT recipients with HCC between 1984 and 2013.

RESULTS

Overall patient and recurrence-free survivals were 83%, 68%, 60% and 79%, 63%, and 56% at 1-, 3-, and 5-years, respectively. Hepatocellular carcinoma recurred in 117 recipients, with a median time to recurrence of 15 months, involving the lungs (59%), abdomen/pelvis (38%), liver (35%), bone (28%), pleura/mediastinum (12%), and brain (5%). Multivariate predictors of recurrence included tumor grade/differentiation (G4/poor diff hazard ratio [HR] 8.86; G2-3/mod-poor diff HR 2.56), macrovascular (HR 7.82) and microvascular (HR 2.42) invasion, nondownstaged tumors outside Milan criteria (HR 3.02), nonincidental tumors with radiographic maximum diameter ≥ 5 cm (HR 2.71) and <5 cm (HR 1.55), and pretransplant neutrophil-to-lymphocyte ratio (HR 1.77 per log unit), maximum alpha fetoprotein (HR 1.21 per log unit), and total cholesterol (HR 1.14 per SD). A pretransplantation model incorporating only known radiographic and laboratory parameters had improved accuracy in predicting HCC recurrence (C statistic 0.79) compared with both Milan (C statistic 0.64) and UCSF (C statistic 0.64) criteria alone. A novel clinicopathologic prognostic nomogram included explant pathology and had an excellent ability to predict post-transplant recurrence (C statistic 0.85).

CONCLUSIONS

In the largest single-institution experience with LT for HCC, excellent long-term survival was achieved. Incorporation of routine pretransplantation biomarkers to existing radiographic size criteria significantly improves the ability to predict post-transplant recurrence, and should be considered in recipient selection. A novel clinicopathologic prognostic nomogram accurately predicts HCC recurrence after LT and may guide frequency of post-transplantation surveillance and adjuvant therapy.

Current challenges in liver transplantation for hepatocellular carcinoma

Liver transplantation (LT) is the best option of cure for hepatocellular carcinoma (HCC). Notwithstanding several alternatives, Milan Criteria remain the cornerstone for patient selection. Currently, expanded criteria patients are unsuitable for LT without taking downstaging approaches and response to therapies into consideration. Relative weight of HCC as indication to LT is increasing and that generates competition with MELD-described non-cancer indications. Allocation policies should be adjusted accordingly, considering principles of urgency and utility in the management of the waiting list and including transplant benefit to craft equitable criteria to deal with the limited resource of donated grafts. Maximization of cost-effectiveness of LT in HCC can be also pursued through changes in immunosuppression policies and multimodal management of post-transplant recurrences. This review is focused on those constantly mutating challenges that have to be faced by anyone dealing with the management of HCC in the context of liver transplantation.

Role of liver transplantation for hepatocellular carcinoma

This review evaluates the available evidence to establish the role of liver transplantation in the management of hepatocellular carcinoma in India. Most liver transplants in India are living donor transplants due to the paucity of brain dead organ donors. There is sufficient evidence to permit allocation of organs to patients with tumors within the Milan criteria. If the waiting list time is more than 6 months, a down-staging locoregional treatment modality such a trans-arterial chemoembolization, radiofrequency ablation, resection or percutaneous ethanol injection may be used to prevent disease progression. Allocating scarce livers to patients with more advanced tumors may not be justifiable. However, living donor liver transplantation may be offered to medically fit patients with hepatocellular carcinoma with cirrhosis, offering a guarded prognosis to patients beyond the Milan or UCSF criteria. Vascular invasion and extra-hepatic disease should be absolute contraindications to liver transplantation.

Liver transplantation for hepatic tumors: A systematic review

Improvements in the medical and pharmacological management of liver transplantation (LT) recipients have led to a better long-term outcome and extension of the indications for this procedure. Liver tumors are relevant to LT; however, the use of LT to treat malignancies remains a debated issue because the high risk of recurrence. In this review we considered LT for hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), liver metastases (LM) and other rare tumors. We reviewed the literature, focusing on the past 10 years. The highly selected Milan criteria of LT for HCC (single nodule < 5 cm or up to 3 nodules < 3 cm) have been recently extended by a group from the University of S. Francisco (1 lesion < 6.5 cm or up to 3 lesions < 4.5 cm) with satisfying results in terms of recurrence-free survival and the “up-to-seven criteria”. Moreover, using these criteria, other transplant groups have recently developed downstaging protocols, including surgical or loco-regional treatments of HCC, which have increased the post-operative survival of recipients. CCA may be treated by LT in patients who cannot undergo liver resection because of underlying liver disease or for anatomical technical challenges. A well-defined protocol of chemoirradiation and staging laparotomy before LT has been developed by the Mayo Clinic, which has resulted in long term disease-free survival comparable to other indications. LT for LM has also been investigated by multicenter studies. It offers a real benefit for metastases from neuroendocrine tumors that are well differentiated and when a major extrahepatic resection is not required. If LT is an option in these selected cases, liver metastases from colorectal cancer is still a borderline indication because data concerning the disease-free survival are still lacking. Hepatoblastoma and hemangioendothelioma represent rare primary tumors for which LT is often the only possible and effective cure because of the frequent multifocal, intrahepatic nature of the disease. LT is a very promising procedure for both primary and secondary liver malignancies; however, it needs an accurate evaluation of the costs and benefits for each indication to balance the chances of cure with actual organ availability.

Liver transplantation: past, present and future

The first human liver transplant operation was performed by Thomas Starzl in 1963. The next two decades were marked by difficulties with donor organ quality, recipient selection, operative and perioperative management, immunosuppression and infectious complications. Advances in each of these areas transformed liver transplantation from an experimental procedure to a standard treatment for end-stage liver disease and certain cancers. From the handful of pioneering programmes, liver transplantation has expanded to hundreds of programmes in >80 countries. 1-year patient survival rates have exceeded 80% and outcomes continue to improve. This success has created obstacles. Ongoing challenges of liver transplantation include those concerning donor organ shortages, recipients with more advanced disease at transplant, growing need for retransplantation, toxicities and adverse effects associated with long-term immunosuppression, obesity and NASH epidemics, HCV recurrence and the still inscrutable biology of hepatocellular carcinoma. This Perspectives summarizes this transformation over time and details some of the challenges ahead.

The first report of orthotopic liver transplantation in the Western world

Until the present time, the first experimental liver transplant which led to the development of human liver transplantation is attributed to C. Stuart Welch who performed a heterotopic transplant in the canine species in 1955. In 1956, Jack Cannon is credited with the first animal orthotopic liver transplant although the species was not disclosed. This report is intended to set the historical record straight by acknowledging that Vittorio Staudacher in 1952 was the first to perform a liver transplant in a large animal model.

A review of transplant immunology

Transplantation has been an accepted treatment for end-stage organ disease for more than 30 years. Advances in transplant immunology are the cornerstone to the success of the body’s ability to accept the allografted organ while continuing to perform immune functions such as tumor surveillance and fighting pathogenic organisms. This article describes immunosuppressant regimens and attendant nursing considerations in the care of transplant patients.

Neurologic complications in adult living donor liver transplant patients: an underestimated factor?

Liver transplantation is the only curative treatment in patients with end-stage liver disease. Neurological complications (NC) are increasingly reported to occur in patients after cadaveric liver transplantation. This retrospective cohort study aims to evaluate the incidence and causes of NC in living donor liver transplant (LDLT) patients in our transplant center. Between August 1998 and December 2005, 121 adult LDLT patients were recruited into our study. 17% of patients experienced NC, and it occurred significantly more frequently in patients with alcoholic cirrhosis (42%) and autoimmune hepatitis (43%) as compared with patients with hepatitis B or C (9/10%, P = 0.013). The most common NC was encephalopathy (47.6%) followed by seizures (9.5%). The choice of immunosuppression by calcineurin inhibitor (Tacrolimus or Cyclosporin A) showed no significant difference in the incidence of NC (19 vs. 17%). The occurrence of NC did not influence the clinical outcome, since mortality rate, median ICU stay and length of hospital stay were similar between the two groups. Most patients who survived showed a nearly complete recovery of their NC. NCs occur in approximately 1 in 6 patients after LDLT and seem to be predominantly transient in nature, without major impact on clinical outcome.

The development of perioperative practices for liver transplantation: advances and current trends

Transplantation is a young medical specialty that has grown rapidly over the past 50 years. Anesthesiologists, surgeons and hepatologists are all essential partners in the process of determining patient outcome. Each specialty has made landmark improvements in patient outcome. However, there is still variability in practice patterns in each of the 3 major specialties. This review will use a historic perspective to explore the unique forces that shaped specific transplant practices and those that gave rise to differences in perioperative practices. Anesthesiologists and surgeons have made significant improvements in the management of blood loss, and coagulation monitoring and intervention. This has improved operative survival and early patient outcome. Perioperative survival has improved despite a worldwide shortage of donor organs and a trend to transplant sicker patients. A smaller pool of donor organs is required to meet the needs of an expanding waiting list. The innovations to reduce deaths on the transplant wait list are reviewed along with their impact on overall patient outcome. The evolving organ shortage is the pinnacle point in shaping future transplant practices. Currently, institutional-specific practices may be reinforced by the informal "tutorship" that is used to train physicians and by the resources available at each site of practice. However, there is evidence that specific intraoperative practices such as the use of a low central venous pressure, selection of vasopressors and certain surgical techniques can modify patient outcome. Further investigation is needed to determine whether the good or the bad associated with each practice prevails and in what unique circumstance.

Acquired immunologic tolerance: with particular reference to transplantation

The first unequivocally successful bone marrow cell transplantation in humans was recorded in 1968 by the University of Minnesota team of Robert A. Good (Gatti et al. Lancet 2: 1366-1369, 1968). This achievement was a direct extension of mouse models of acquired immunologic tolerance that were established 15 years earlier. In contrast, organ (i.e. kidney) transplantation was accomplished precociously in humans (in 1959) before demonstrating its feasibility in any experimental model and in the absence of a defensible immunologic rationale. Due to the striking differences between the outcomes with the two kinds of procedure, the mechanisms of organ engraftment were long thought to differ from the leukocyte chimerism-associated ones of bone marrow transplantation. This and other concepts of alloengraftment and acquired tolerance have changed over time. Current concepts and their clinical implications can be understood and discussed best from the perspective provided by the life and times of Bob Good.

Analysis of long-term outcomes of 3200 liver transplantations over two decades: a single-center experience

OBJECTIVE

Few studies have evaluated long-term outcomes after orthotopic liver transplantation (OLT). This work analyzes the experience of nearly 2 decades by the same team in a single center. Outcomes of OLT and factors affecting survival were analyzed.

METHODS

Retrospective analysis of 3200 consecutive OLTs that were performed at our institution, between February 1984 and December 31, 2001.

RESULTS

Of 2662 recipients, 578 (21.7%) and 659 (24.7%) were pediatric and urgent patients, respectively. Overall 1-, 5-, 10-, and 15-year patient and graft survival estimates were 81%, 72%, 68%, 64% and 73%, 64%, 59%, 55%, respectively. Patient survival significantly improved in the second (1992-2001) versus the era I (1984-1991) of transplantation (P < 0.001). Similarly, graft survival was better in the era II of transplantation (P < 0.02). However, biliary and infectious complications increased in era II. When OLT indications were considered, best recipient survival was obtained in children with biliary atresia (82%, 79%, and 78% at 1, 5, and 10 years, respectively), while malignant disease in adult patients resulted in the worst outcomes of 68% and 43% at 1 and 5 years, post-OLT. Further, patients <18 years and nonurgent recipients exhibited superior survival when compared with recipients >18 years (P < 0.001) or urgent patients (P < 0.001). Of 13 donor and recipient variables, era of OLT, recipient age, urgent status, donor age, donor length of hospital stay, etiology of liver disease, retransplantation, warm and cold ischemia, but not graft type (whole, split, living-donor), significantly impacted patient survival.

CONCLUSIONS

Long-term benefits of OLT are greatest in pediatric and nonurgent patients. Multiple factors involving the recipient, etiology of liver disease, donor characteristics, operative variables, and surgical experience influence long-term survival outcomes. By balancing and matching these factors with a given recipient, optimum results can be achieved.

Chimerism and tolerance in transplantation

Studies in experimental models (1953-1956) demonstrated that acquired donor-specific allotolerance in immunologically immature or irradiated animals is strongly associated with donor leukocyte chimerism. Bone marrow transplantation in immune-deficient or cytoablated human recipients was a logical extension (1968). In contrast, clinical (1959) and then experimental organ transplantation was systematically accomplished in the apparent absence of leukocyte chimerism. Consequently, it was assumed for many years that success with organ and bone marrow transplantation involved fundamentally different mechanisms. With the discovery in 1992 of small numbers of donor leukocytes in the tissues or blood of long-surviving organ recipients (microchimerism), we concluded that organ engraftment was a form of leukocyte chimerism-dependent partial tolerance. In this initially controversial paradigm, alloengraftment after both kinds of transplantation is the product of a double immune reaction in which responses, each to the other, of coexisting donor and recipient immune systems results in variable reciprocal clonal exhaustion, followed by peripheral clonal deletion. It was proposed with Rolf Zinkernagel that the individual alloresponses are the equivalent of the MHC-restricted T cell recognition of, and host response to, intracellular parasites and that the mechanisms of immune responsiveness, or nonresponsiveness, are governed by the migration and localization of the respective antigens. Elucidation of the mechanisms of nonresponsiveness (clonal exhaustion-deletion and immune ignorance) and their regulation removed much of the historical mystique of transplantation. The insight was then applied to improve the timing and dosage of immunosuppression of current human transplant recipients.

Role of tacrolimus in the evolution of liver transplantation

Once regarded as a last-resort therapy for patients with end-stage liver disease, liver transplantation has become a viable therapeutic option because of sweeping improvements in surgical techniques and the development of more powerful immunosuppressive agents. The addition of tacrolimus to the immunosuppression regimen represents a highly potent therapy and a powerful defense against acute rejection. In the decade since tacrolimus was approved for use in the United States, it has become a widely used immunosuppressant in the field of liver transplantation.

Lessons of organ-induced tolerance learned from historical clinical experience1

Although the reductionist approach has served science well for 400 years, the accumulation of details can obscure the truth if the original premise is incorrect. One such premise has been that successful organ transplantation and bone marrow engraftment are fundamentally different outcomes involving separate and distinct mechanisms. Some historical clinical observations pointed to a different conclusion almost from the beginning and included clues about how to induce tolerance with the aid of immunosuppression.

Kidney transplantation under a tolerogenic regimen of recipient pretreatment and low-dose postoperative immunosuppression with subsequent weaning

OBJECTIVE

The purpose of this work was to perform kidney transplantation under a regimen of immunosuppression that facilitates rather than interferes with the recently defined mechanisms of alloengraftment and acquired tolerance.

SUMMARY BACKGROUND DATA

In almost all centers, multiple immunosuppressive agents are given in large doses after kidney transplantation in an attempt to reduce the incidence of acute rejection to near zero. With the elucidation of the mechanisms of alloengraftment and acquired tolerance, it was realized that such heavy prophylactic immunosuppression could systematically subvert the clonal exhaustion-deletion that is the seminal mechanism of tolerance. In addition, it has been established that the rejection response can be made more readily treatable by pretransplant immunosuppression. Consequently, we conducted kidney transplantation in compliance with 2 therapeutic principles: recipient pretreatment and the least possible use of posttransplant immunosuppression.

METHODS

One-hundred fifty unselected renal transplant recipients with a mean age of 51 +/- 15 years and multiple risk factors had pretreatment with approximately 5 mg/kg of rabbit antithymocyte globulin (Thymoglobulin) in the hours before transplantation, under covering bolus doses of prednisone to prevent cytokine reactions. Minimal posttransplant immunosuppression was with tacrolimus monotherapy to which steroids or other agents were added only for the treatment of rejection. At or after 4 months after transplant, spaced-dose weaning from tacrolimus monotherapy was begun in patients who had exhibited a satisfactory course.

RESULTS

One-year actuarial patient and graft survival was 97% and 92%, respectively. Although the incidence of early acute rejection was 37%, only 7% required prolonged treatment with any agent other than tacrolimus. After a follow-up of 6 to 21 months, the mean serum creatinine in patients with functioning grafts is 1.8 +/- 1.0 mg/dL. Seventy-three percent of the patients met the criteria for spaced weaning. Although rejection episodes occasionally required restoration of daily treatment, 94 (63%) of the 150 patients currently receive tacrolimus in spaced doses ranging from every other day to once a week.

CONCLUSIONS

With this approach to immunosuppression, it has been possible to avoid early posttransplant overimmunosuppression and thereby to promote the evolution of a degree of partial tolerance sufficient to undertake substantial dose reduction. The strategy, which is applicable for all organ grafts, constitutes a paradigm shift in transplant management at our center.

Overview of pediatric liver transplantation

Liver transplantation is a successful and useful therapy for children with chronic or end-stage liver disease and those with a variety of extrahepatic metabolic diseases that can be corrected by liver replacement. Major developments in medical management, donor availability and procurement, operative techniques, and post-operative management all contributed to the dramatic improvement in outcome and growth of liver transplantation from its inception in 1963 [1,7,21]. The excellent long-term outcomes that have been achieved are the product of the coordinated efforts of liver transplant surgeons, specialists in pediatric hepatology and other medical areas, nurses, local practitioners, and the patients and their families. Future advances in transplant immunobiology, organ availability and infection control are likely to lead to still greater improvements in short and long-term outcome [34].

The co-development of liver and kidney transplantation (1955-1967)

Between 1955 and the end of 1967, the framework of clinical transplantation that exists today was established in a small number of centers in continental Europe, Great Britain, and the United States. At first, the primary organ was the kidney, but efforts to transplant the kidney soon strongly influenced the development of liver and ultimately all other kinds of organ transplantation. This paper reviews the pertinent history of these developments as outlined in a lecture given in January 2003 in Bangkok on the occasion of the Prince Mahidol Award for a life's work in the field of organ transplantation.

Tolerogenic immunosuppression for organ transplantation

BACKGROUND

Insight into the mechanisms of organ engraftment and acquired tolerance has made it possible to facilitate these mechanisms, by tailoring the timing and dosage of immunosuppression in accordance with two therapeutic principles: recipient pretreatment, and minimum use of post-transplant immunosuppression. We aimed to apply these principles in recipients of renal and extrarenal organ transplants.

METHODS

82 patients awaiting kidney, liver, pancreas, or intestinal transplantation were pretreated with about 5 mg/kg of a broadly reacting rabbit antithymocyte globulin during several hours. Post-transplant immunosuppression was restricted to tacrolimus unless additional drugs were needed to treat breakthrough rejection. After 4 months, patients on tacrolimus monotherapy were considered for dose-spacing to every other day or longer intervals.

FINDINGS

We frequently saw evidence of immune activation in graft biopsy samples, but unless this was associated with graft dysfunction or serious immune destruction, treatment usually was not intensified. Immunosuppression-related morbidity was virtually eliminated. 78 (95%) of 82 patients survived at 1 year and at 13-18 months. Graft survival was 73 (89%) of 82 at 1 year and 72 (88%) of 82 at 13-18 months. Of the 72 recipients with surviving grafts, 43 are on spaced doses of tacrolimus monotherapy: every other day (n=6), three times per week (11), twice per week (15), or once per week (11).

INTERPRETATION

The striking ability to wean immunosuppression in these recipients indicates variable induction of tolerance. The simple therapeutic principles are neither drug-specific nor organ-specific. Systematic application of these principles should allow improvements in quality of life and long-term survival after organ transplantation.