Living donor liver transplantation using dual grafts from two donors: a feasible option to overcome small-for-size graft problems?

Benefit and harm of waiting time in liver transplantation for HCC

Liver transplantation is the most successful treatment for limited-stage HCC. The waiting time for liver transplantation (LT) can be a critical factor affecting the oncological prognosis and outcome of patients with HCC. Efficient strategies to optimize waiting time are essential to maximize the benefits of LT and to reduce the harm of delay in transplantation. The ever-increasing demand for donor livers emphasizes the need to improve the organization of the waiting list for transplantation and to optimize organ availability for patients with and without HCC. Current progress in innovations to expand the donor pool includes the implementation of living donor LT and the use of grafts from extended donors. By expanding selection criteria, an increased number of patients are eligible for transplantation, which necessitates criteria to prevent futile transplantations. Thus, the selection criteria for LT have evolved to include not only tumor characteristics but biomarkers as well. Enhancing our understanding of HCC tumor biology through the analysis of subtypes and molecular genetics holds significant promise in advancing the personalized approach for patients. In this review, the effect of waiting time duration on outcome in patients with HCC enlisted for LT is discussed.

A Novel Method for the Prevention and Treatment of Small-for-Size Syndrome in Liver Transplantation

BACKGROUND

Currently there is no consensus on the optimal management of small-for-size syndrome following liver transplantation. Here we describe a technique to alleviate portal hypertension and improve the hepatocyte reperfusion in small-for-size liver transplantation in a Lewis rat model.

METHODS

The rats underwent trans-portal vein intra-hepatic portosystemic shunt using a self-developed porous conical tube (TPIPSS: Fig. 1) on small-for-size liver transplants (SFS) with right lobe graft. The treatment effect was evaluated by comparing hemodynamic parameters, morphological changes, serum parameters, ET-1 and eNOS expression, hepatocyte proliferation and apoptosis, CYP3A2 levels, postoperative complications, and survival between the two groups with SFS liver transplants.

RESULTS

Porous conical prosthesis prolonged the filling time of small-for-size grafts. Moreover, grafts with TPIPSS showed a lower portal vein pressure, improved microcirculatory flow, alleviated histological changes, decreased ET-1 and increased eNOS expressions, and significantly less damage to liver function comparing to grafts without TPIPSS. Mean survival and overall 30-day survival were significantly higher in the TPIPSS group.

CONCLUSIONS

These results demonstrate that porous conical tube as trans-portal vein intra-hepatic portosystemic shunt device is an effective way to alleviate portal vein hypertension and improve hepatocyte reperfusion after small-for-size liver transplantation.

Small-for-size syndrome in liver transplantation: Definition, pathophysiology and management

BACKGROUND

Since the first success in an adult patient, living donor liver transplantation (LDLT) has become an universally used procedure. Small-for-size syndrome (SFSS) is a well-known complication after partial LT, especially in cases of adult-to-adult LDLT. The definition of SFSS slightly varies among transplant physicians. The use of a partial liver graft has risks of SFSS development. Persistent portal vein (PV) hypertension and PV hyper-perfusion after LT were identified as the main factors. Hence, various approaches were explored to modulate PV flow and decrease PV pressure in order to alleviate this syndrome. Herein, the definition, clinical symptoms, pathophysiology, basic research, as well as preventive and treatment strategies for SFSS are reviewed based on an extensive review of the literature and on our own experiences.

DATA SOURCES

The articles were collected through PubMed using search terms "liver transplantation", "living donor liver transplantation", "living liver donation", "partial graft", "small-for-size graft", "small-for-size syndrome", "graft volume", "remnant liver", "standard liver volume", "graft to recipient body weight ratio", "sarcopenia", "porcine", "swine", and "rat". English publications published before March 31, 2020 were included in this review.

RESULTS

Many transplant surgeons performed PV flow modulation, including portocaval shunt, splenic artery ligation and splenectomy. With these techniques, patient outcome has been improved even when using a "small" graft. Other factors, such as preoperative recipients' nutritional and skeletal muscle status, graft congestion, and donor factors, were also identified as risk factors which all have been addressed using various strategies.

CONCLUSIONS

The surgical approach controlling PV flow and pressure could help to prevent SFSS especially in severely ill recipients. In the absence of efficacious medications to resolve SFSS, conservative treatments, including aggressive fluid balance correction for massive ascites, anti-microbiological therapy to prevent or control sepsis and intensive nutritional therapy, are all required if SFSS could not be prevented.

Splenic devascularization can replace splenectomy during adult living donor liver transplantation - a historical cohort study

Simultaneous splenectomy (SSPX) in adult living donor liver transplantation (ALDLT) has definitely beneficial roles such as portal flow modulation in small-for-size graft and correction of hypersplenism-related pancytopenia, and so on, but disastrous complications after SSPX often occur. For the first time, we devised unique and innovative splenic devascularization (SDV) procedure to alleviated untoward effects of SSPX but to maintain its benefits for the indicated patients. From April 2013 to December 2014, 520 recipients underwent ALDLT, and the SSPX and SDV were simultaneously performed in 62 (11.9%) and 61 (11.7%) patients, respectively. The most common indication was hypersplenism-related pancytopenia (n = 101), small-for-size graft (n = 14), hepatitis C virus (HCV) (n = 7), and splenic artery aneurysm (n = 1). Postoperative small-for-size graft syndrome (SFSS) was absent in both SSPX and SDV, and preoperative pancytopenia was improved in both groups since postoperative 1 week, although SSPX was more substantial than SDV. Preoperative splenic volume (706.2 ± 282.9 ml) after SDV significantly decreased to 425.5 ± 204.4 ml on 1 month, respectively. In contrast to SDV, SSPX resulted in longer operation time and higher incidence of postoperative complications including mortality. In conclusion, SDV can replace SSPX during ALDLT without hampering its beneficial roles seriously, but get rid of splenectomy-related lethal complication.

The International Liver Transplantation Society Living Donor Liver Transplant Recipient Guideline

Living donor liver transplantation (LDLT) has been increasingly embraced around the world as an important strategy to address the shortage of deceased donor livers. The aim of this guideline, approved by the International Liver Transplantation Society (ILTS), is to provide a collection of expert opinions, consensus, and best practices surrounding LDLT. Recommendations were developed from an analysis of the National Library of Medicine living donor transplantation indexed literature using the Grading of Recommendations Assessment, Development and Evaluation methodology. Writing was guided by the ILTS Policy on the Development and Use of Practice Guidelines (www.ilts.org). Intended for use by physicians, these recommendations support specific approaches to the diagnostic, therapeutic, and preventive aspects of care of living donor liver transplant recipients.

Compared to cadaveric liver transplantation, live donor LT (LDLT) is challenged by ethical, medical and surgical considerations, many of which are still unresolved. The aim of this guideline is to provide a collection of expert opinions, consensus, and best practices surrounding LDLT.

A review of current status of living donor liver transplantation

Living donor liver transplantation (LDLT) has become an inevitable procedure in Asia due to its shortage of deceased donor under the influence of the religion and native cultures. Through a broad variety of experience, LDLT has been evolved and extended its indication. Although there have been many surgical and ethical efforts to prevent donor risk, concerns of donor's safety still are remaining questions due to its strict selection criteria. Therefore, dual grafts LDLT or ABO incompatible (ABO-I) LDLT may be effective means in its application and safety aspect. Many Asian LDLT centers have pointed out the useful extended criteria of LDLT for hepatocellular carcinoma (HCC), but the applicability of extended criteria should be validated and standardized by worldwide prospective studies based on the Milan criteria. Recent struggling efforts have been reported to surmount extensive portal vein thrombosis and Budd-Chiari syndrome which were previously contraindicated to LDLT. There is no doubt that LDLT is a surely complicated therapy to be performed successfully and requires devoted efforts by surgeons and co-workers. Nonetheless, comprehensive increasing understandings of partial graft LT and improvements of surgical techniques with challenges to obstacles in LDLT will make its prosperity with satisfactory outcomes.

Endoscopic management of bile leakage after liver transplantation

BACKGROUND/AIMS

Endoscopic retrograde cholangiopancreatography (ERCP) can be an effective treatment for bile leakage after liver transplantation. We evaluated the efficacy of endoscopic treatment in liver transplantation in patients who developed bile leaks.

METHODS

Forty-two patients who developed bile leaks after liver transplantation were included in the study. If a bile leak was observed on ERCP, a sphincterotomy was performed, and a nasobiliary catheter was then inserted. If a bile leak was accompanied by a bile duct stricture, either the stricture was dilated with balloons, followed by nasobiliary catheter insertion across the bile duct stricture, or endoscopic retrograde biliary drainage was performed.

RESULTS

In the bile leakage alone group (22 patients), endoscopic treatment was technically successful in 19 (86.4%) and clinically successful in 17 (77.3%) cases. Among the 20 patients with bile leaks with bile duct strictures, endoscopic treatment was technically successful in 13 (65.0%) and clinically successful in 10 (50.0%) cases. Among the 42 patients who underwent ERCP, technical success was achieved in 32 (76.2%) cases and clinical success was achieved in 27 (64.3%) cases.

CONCLUSIONS

ERCP is an effective and safe therapeutic modality for bile leaks after liver transplantation. ERCP should be considered as an initial therapeutic modality in post-liver transplantation patients.

Living donor liver transplantation using dual grafts: Experience and lessons learned from cases worldwide

In living donor liver transplantation (LDLT), insufficient graft volume could result in small-for-size syndrome in recipients, whereas major liver donation predisposes the donor to a high risk of posthepatectomy liver failure. Dual graft LDLT is therefore introduced to obtain combined graft sufficiency. To date, 367 patients have been reported worldwide. We reviewed all the relevant literature, with a special focus on 43 case reports containing enough data to extract and analyze. A simple decision-making algorithm was developed. Dual graft LDLT is indicated when (1) a single donation is unacceptable due to graft-to-recipient size mismatch; (2) the future liver remnant is insufficient in the single donor after major resection; or (3) there is a significant underlying disorder or anatomical variation within the donor liver. The outcome of dual graft LDLT is reported to be comparable with that of single donor LDLT. Unilateral graft atrophy was found in 7 of the 43 patients, predominantly in the right-sided, heterotopic and initially smaller grafts. Technically, the heterotopic implantation and complex vascular reconstruction are the most demanding. Elaborate surgical planning and modification are needed. Ethical concerns about involving a second living donor need to be addressed. In conclusion, dual graft LDLT should be prudently performed in select cases by surgeons of proven expertise when single donation is unacceptable and a second living donor is available. The decision-making criteria need to be standardized. More surgical modification and clinical research are needed.

The role of adult living donor liver transplantation and recent advances

Twenty years since the first cases were described, adult living donor liver transplantation (ALDLT) is now considered a valid option to expand the donor pool in view of the ongoing shortage of organs and the high waiting list mortality rate. Despite the rapid evolution and acceptance of this complex process of donation and transplantation in clinical practice, the indications, outcome, ethical considerations and quality and safety aspects continue to evolve based on new data from large cohort studies. This article reviews the surgical and clinical advances in the field of liver transplantation, focusing on technical refinements and discussing the issues that may lead to a further expansion of this complex surgical procedure and the role of ALDLT.

Early Graft Dysfunction in Living Donor Liver Transplantation and the Small for Size Syndrome

LDLT has arisen as a viable means to reduce waitlist mortality. However, its widespread embrace by the liver transplant community has been met with frustration centered on donor morbidity and small-for-size-syndrome. Focusing on the later entity, we describe the initial recognition of this early graft dysfunction, the theorized pathophysiology and solutions to remedy its emergence.

Outcome of patients undergoing right lobe living donor liver transplantation with small-for-size grafts

AIM: To investigate the outcome of living donor liver transplantation (LDLT) recipients transplanted with small-for-size grafts (SFSGs).

METHODS: Between November 2001 and December 2010, 196 patients underwent LDLT with right lobe liver grafts at our center. Recipients were divided into 2 treatment groups: group A with an actuarial graft-to-recipient weight ratio (aGRWR) < 0.8% (n = 45) and group B with an aGRWR ≥ 0.8% (n = 151). We evaluated serum liver function markers within 4 wk after transplantation. We also retrospectively evaluated the outcomes of these patients for potential effects related to the recipients, the donors and the transplantation procedures based upon a review of their medical records.

RESULTS: Small-for-size syndrome (SFSS) developed in 7 of 45 patients (15.56%) in group A and 9 of 151 patients (5.96%) in group B (P = 0.080). The levels of alanine aminotransferase and aspartate aminotransferase in group A were higher than those in group B during early period after transplantation, albeit not significantly. The cumulative 1-, 3- and 5-year liver graft survival rates were 82.22%, 71.11% and 71.11% for group A and 81.46%, 76.82%, and 75.50% for group B patients, respectively (P = 0.623). However, univariate analysis of risk factors associated with graft survival in group A demonstrated that the occurrence of SFSS after LDLT was the only significant risk factor affecting graft survival (P < 0.001). Furthermore, multivariate analysis of our data did not identify any additional significant risk factors accounting for poor graft survival.

CONCLUSION: Our study suggests that LDLT recipients with an aGRWR < 0.8% may have liver graft outcomes comparable to those who received larger size grafts. Further studies are required to ascertain the safety of using SFSGs.

Dual liver transplantation

Reperfusion is the key strategy in acute ST-segment elevation myocardial infarction (STEMI) care, and it is time-dependent. Shortening the time from symptom to reperfusion and choosing the optimal reperfusion strategy for STEMI patients are great challenges in practice. We need to improve upon the problems of low reperfusion rate, non-standardized treatment, and economic burden in STEMI care. This article briefly reviews the current status of reperfusion strategy in STEMI care, and also introduces what we will do to bridge the gap between the guidelines and implementation in the clinical setting through the upcoming China STEMI early reperfusion program.

Establishment of animal model of dual liver transplantation in rat

The animal model of the whole-size and reduced-size liver transplantation in both rat and mouse has been successfully established. Because of the difficulties and complexities in microsurgical technology, the animal model of dual liver transplantation was still not established for twelve years since the first human dual liver transplantation has been made a success. There is an essential need to establish this animal model to lay a basic foundation for clinical practice. To study the physiological and histopathological changes of dual liver transplantation, “Y” type vein from the cross part between vena cava and two iliac of donor and “Y’ type prosthesis were employed to recanalize portal vein and the bile duct between dual liver grafts and recipient. The dual right upper lobes about 45–50% of the recipient liver volume were taken as donor, one was orthotopically implanted at its original position, the other was rotated 180° sagitally and heterotopically positioned in the left upper quadrant. Microcirculation parameters, liver function, immunohistochemistry and survival were analyzed to evaluate the function of dual liver grafts. No significant difference in the hepatic microcirculatory flow was found between two grafts in the first 90 minutes after reperfusion. Light and electronic microscope showed the liver architecture was maintained without obvious features of cellular destruction and the continuity of the endothelium was preserved. Only 3 heterotopically positioned graft appeared patchy desquamation of endothelial cell, mitochondrial swelling and hepatocytes cytoplasmic vacuolization. Immunohistochemistry revealed there is no difference in hepatocyte activity and the ability of endothelia to contract and relax after reperfusion between dual grafts. Dual grafts made a rapid amelioration of liver function after reperfusion. 7 rats survived more than 7 days with survival rate of 58.3.%. Using “Y” type vein and bile duct prosthesis, we successfully established a novel rat model of dual right upper liver lobe transplantation.

Trends in liver transplantation 2011

This review will highlight some of the important recent trends in liver transplantation. When possible, we will compare and contrast these trends across various regions of the world, in an effort to improve global consensus and better recognition of emerging data.

Impact of human T cell leukemia virus type 1 in living donor liver transplantation

Human T cell leukemia virus type 1 (HTLV-1) is an endemic retrovirus in southwestern Japan, which causes adult T cell leukemia (ATL) or HTLV-1 associated myelopathy in a minority of carriers. Here, we investigated the impact of HTLV-1 status in living donor liver transplantation (LDLT). Twenty-six of 329 (7.9%) HTLV-1 carriers underwent primary LDLT. One recipient negative for HTLV-1 before LDLT received a graft from an HTLV-1 positive donor. Eight donors were HTLV-1 positive. Twenty-seven recipients (13 male and 14 female; mean age 52.5 years) were reviewed retrospectively. ATL developed in four recipients who ultimately died. The intervals between LDLT and ATL development ranged from 181 to 1315 days. Of the four ATL recipients, two received grafts from HTLV-1 positive donors and two from negative donors. The 1-, 3- and 5-year HTLV-1 carrier survival rates were 91.3%, 78.3% and 66.3%, respectively. Fulminant hepatic failure as a pretransplant diagnosis and a pretransplant MELD score ≥ 15 was identified as risk factors for ATL development in this study (p = 0.001 and p = 0.041, respectively). In conclusion, LDLT can be performed for HTLV-1 positive recipients. However, when fulminant hepatic failure is diagnosed, LDLT should not be performed until further studies have revealed the mechanisms of ATL development.

The impact of IL28B genetic variants on recurrent hepatitis C in liver transplantation: significant lessons from a dual graft case

IL28B genetic polymorphism is related to interferon-sensitivity in chronic hepatitis C, but the significance of grafts carrying different genotypes from recipients is still unclear in liver transplantation. A 51-year-old Japanese male carrying a minor genotype underwent dual liver transplantation for liver cirrhosis due to hepatitis C virus (HCV). The left lobe graft carried a major genotype, and the right a minor genotype. He achieved virological response during the course of pegylated-interferon and ribavirin therapy against recurrent hepatitis C for 2 years, but HCV relapsed immediately at the end of the therapy. Two years after antiviral therapy, liver biopsy was performed from each graft. The specimens showed A1F0 in the left lobe graft and A2F2 in the right. Moreover, quantitative polymerase chain reaction was performed using RNA extracted from each specimen to see there was no HCV RNA in the left lobe whereas there was in the right. This case provides clear evidence that IL28B genetic variants determine interferon sensitivity in recurrent hepatitis C following liver transplantation, which could result in new strategies for donor selection or for posttransplant antiviral therapy to HCV positive recipients.

Living donor liver transplantation

PURPOSE OF REVIEW

The widening gap between the growing number of liver transplant candidates and the supply of deceased donor organs became a strong motivation for the development of living donor liver transplantation (LDLT). LDLT has gone through its developmental phase and become an established life-saving procedure.

RECENT FINDINGS

Despite the challenging nature of the technique of LDLT, there have been continuous innovations. A better understanding of complex surgical anatomy and physiologic differences of partial hepatic allografts has helped to avoid graft congestion, small-for-size syndrome, or graft hypoperfusion from portal flow steal. LDLT for patients with high Model for End-Stage Liver Disease score can achieve comparable results with deceased donor liver transplantation (DDLT). Size limitation of partial grafts can be overcome with dual grafts. The extended application of LDLT for hepatocellular carcinoma beyond Milan criteria seems feasible but at the cost of slightly compromised survival. More information has become available for prospective donors about the consequences of living liver donation in terms of psychosocial impact.

SUMMARY

Although LDLT is still evolving, it has become the most effective alternative to DDLT. Proven or potential benefit of LDLT include the superior quality of the allograft despite the smaller size, selection of proper timing for transplantation and a reduced waiting time, which prevents waiting list mortality.

Living donor liver transplantation using dual grafts: Ultrasonographic evaluation

AIM: To evaluate the dual-graft living donor liver transplantation (LDLT) with ultrasonography, with special emphasis on the postoperative complications.

METHODS: From January 2002 to August 2007, 110 adult-to-adult LDLTs were performed in West China Hospital of Sichuan University. Among them, dual-graft implantations were performed in six patients. Sonographic findings of the patients were retrospectively reviewed.

RESULTS: All the six recipients survived the dual-graft adult-to-adult LDLT surgery. All had pleural effusion. Four patients had episodes of postoperative abdominal complications, including fluid collection between the grafts in three patients, intrahepatic biliary dilatation in two, hepatofugal portal flow of the left lobe in two, and atrophy of the left lobe in one.

CONCLUSION: Although dual-graft LDLT takes more efforts and is technically complicated, it is safely feasible. Postoperative sonographic monitoring of the recipient is important.

Dual living donor liver transplantation with ABO-incompatible and ABO-compatible grafts to overcome small-for-size graft and ABO blood group barrier

ABO blood group compatibility has been regarded as an essential prerequisite for successful adult living donor liver transplantation (LDLT). Novel strategies for overcoming the ABO blood group barrier, however, have markedly improved the results of ABO-incompatible (ABOi) LDLT. We describe our strategies for dual graft LDLT to cope with ABO-incompatibility and small-for-size graft syndrome in 3 patients who underwent dual graft LDLT with ABOi and ABO-compatible (ABOc) grafts. One patient received a modified right lobe graft from an ABOi living donor and a left lateral section graft from an ABOc deceased donor, whereas the other 2 patients received 2 left lobe or left lateral section grafts from ABOi and ABOc living donors. To overcome the ABO-blood barrier, each patient was treated with preoperative anti-CD20 antibody (rituximab 375 mg/m(2)), perioperative plasma exchange, and hepatic arterial infusion. All 3 patients were males, of mean age 47.7 years (range, 40 approximately 52 years) and mean Model for End-Stage Liver Disease score 12.3 (range, 9 approximately 15). The mean graft-to-recipient weight ratio was 0.99%. All patients remain alive after a mean follow-up period of 9.5 months (range, 8.0 approximately 10.7 months). All 6 grafts have functioned normally. There were no episodes of antibody-mediated rejection or biliary complication. Dual LDLT with ABOi and ABOc grafts can be a feasible solution for simultaneously overcoming both the ABO blood group barrier and small-for-size graft syndrome.

Emergent right lobe adult-to-adult living-donor liver transplantation for high model for end-stage liver disease score severe hepatitis

The aim of this study was to explore the feasibility of emergency right lobe adult-to-adult living-donor liver transplantation (LDLT) for high model for end-stage liver disease (MELD) score severe hepatitis. Consecutive 10 high MELD score severe hepatitis patients underwent emergency right lobe adult-to-adult LDLT in our hospital from April to December 2007. The MELD score was 34.50 +/- 2.088. The outcomes of these recipients were retrospectively analyzed. Among them, eight cases of ABO blood group were identical and two cases compatible, one case was Rh negative. Two recipients died and the rest of the recipients and all donors are safe; perioperative and 2-year survival rate was 80%. The mean graft-recipient weight ratio (GRWR) was 1.27% +/- 0.25%, and graft volume to recipient standard liver volume ratio (GV/ESLVR) was 56.7% +/- 6.75%. Of the 10 patients, three received right lobe grafts with middle hepatic vein (MHV), four without MHV, three without MHV but followed by V and VIII hepatic vein outflow reconstruction. An encouraging outcome was achieved in this group: elevated serum creatinine, serum endotoxin, decreased serum prothrombin activity, and Tbil returned to normal on postoperative days 3, 7, 14, and 28, respectively. One-year survival rate was 80%. Outcomes of emergency right lobe adult-to-adult LDLT for high MELD score severe hepatitis were fairly encouraging and acceptable. Emergency right lobe adult-to-adult LDLT is an effective and life-saving modality for high MELD score acute liver failure patients following severe hepatitis.

New prediction factors of small-for-size syndrome in living donor adult liver transplantation for chronic liver disease

Small-for-size syndrome (SFSS), which is characterized by synthetic dysfunction and prolonged cholestasis, is a major cause of worse short-term prognoses after living donor adult liver transplantation (LDALT). However, the risks of SFSS remain unclear. The aim of this study was to clarify the risks of SFSS, which were analysed in 172 patients who underwent LDALT for chronic liver disease. Graft types included left lobe with caudate lobe graft (n = 110) and right lobe graft (n = 62). Thirty-four cases (24 with left lobe grafts and 10 with right lobe grafts) were determined as SFSS. SFSS developed even if the actual graft-to-recipient standard liver volume ratio was >40%. Logistic regression analysis revealed three independent factors associated with SFSS development in left and right lobe grafts: donor age, actual graft-to-recipient native liver volume ratio, and Child's score. Donor age and actual graft-to-recipient native liver volume ratio may become predictive factors for SFSS development in left and right lobe grafts in patients undergoing LDALT.

22 Levertransplantatie

In 1963 verrichtte Thomas Starzl in Denver de eerste levertransplantatie bij de mens. In 1966 werden in Nederland de eerste twee (auxiliaire, zie par. 22.3.6) levertransplantaties verricht in Leiden en Arnhem, in 1968 startte Cambridge. Helaas resulteerden de eerste levertransplantaties niet in langetermijnoverleving als gevolg van niet-optimale operatietechniek, matige immuunsuppressie en onbekendheid met complicaties.

Report of the Paris consensus meeting on expanded criteria donors in liver transplantation

Because of organ shortage and a constant imbalance between available organs and candidates for liver transplantation, expanded criteria donors are needed. Experience shows that there are wide variations in the definitions, selection criteria, and use of expanded criteria donors according to different geographic areas and different centers. Overall, selection criteria for donors have tended to be relaxed in recent years. Consensus recommendations are needed. This article reports the conclusions of a consensus meeting held in Paris in March 2007 with the contribution of experts from Europe, the United States, and Asia. Definitions of expanded criteria donors with respect to donor variables (including age, liver function tests, steatosis, infections, malignancies, and heart-beating versus non-heart-beating, among others) are proposed. It is emphasized that donor quality represents a continuum of risk rather than "good or bad." A distinction is made between donor factors that generate increased risk of graft failure and factors independent of graft function, such as transmissible infectious disease or donor-derived malignancy, that may preclude a good outcome. Updated data concerning the risks associated with different donor variables in different recipient populations are given. Recommendations on how to safely expand donor selection criteria are proposed.