A Worldwide Survey of Live Liver Donor Selection Policies at 24 Centers With a Combined Experience of 19 009 Adult Living Donor Liver Transplants

Indications and results of right-lobe living donor liver transplantation

The shortage of deceased liver donor organs over the years has always posed the need to expand the donor pool. A viable alternative to deceased donors is that of the living donor. Indeed, the living donor in liver transplantation, initially in pediatric transplantation, but for several years now also in adult transplantation, is a more than viable alternative to deceased liver donation. In fact, right liver lobe donation has proven to be a surgical procedure with low impact on the donor's life in terms of morbidity and mortality, with excellent results in recipients of such organs. In recent years, an increasing number of studies have been published that show excellent results in right-lobe living donor liver transplantation, encouraging this practice not only in countries that have historically had a shortage of deceased donor organs, such as Asian countries, but making it a practice of increasing use in Western countries as well. In addition, thanks to improvements in surgical technique and the experience of high-volume centers, this surgery has also begun to be performed using minimally invasive surgical techniques, allowing us to envision ever better outcomes for both donor and recipient in the coming years.

Psychosocial evaluation of living liver donors-State of current practices in the United States

We surveyed living donor liver transplant programs in the United States to describe practices in the psychosocial evaluation of living donors focused on (1) composition of psychosocial team; (2) domains, workflow, and tools of the psychosocial assessment; (3) absolute and relative mental health-related contraindications to donation; and (4) postdonation psychosocial follow-up. We received 52 unique responses, representing 33 of 50 (66%) of active living donor liver transplant programs. Thirty-one (93.9%) provider teams included social workers, 22 (66.7%) psychiatrists, and 14 (42.4%) psychologists. Validated tools were rarely used, but domains assessed were consistent. Respondents rated active alcohol (93.8%), cocaine (96.8%), and opioid (96.8%) use disorder, as absolute contraindications to donation. Active suicidality (97%), self-injurious behavior (90.9%), eating disorders (87.9%), psychosis (84.8%), nonadherence (71.9%), and inability to cooperate with the evaluation team (78.1%) were absolute contraindications to donation. There were no statistically significant differences in absolute psychosocial contraindications to liver donation between geographical areas or between large and small programs. Programs conduct postdonation psychosocial follow-up (57.6%) or screening (39.4%), but routine follow-up of declined donors is rarely conducted (15.8%). Psychosocial evaluation of donor candidates is a multidisciplinary process. The structure of the psychosocial evaluation of donors is not uniform among programs though the domains assessed are consistent. Psychosocial contraindications to living liver donation vary among the transplant programs. Mental health follow-up of donor candidates is not standardized.

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Hilar Anatomy in 3035 Living Liver Donors: A Novel Classification for Donor Surgery and Suitability, Hepatic Surgeries, and Hepatobiliary Interventions

BACKGROUND

This study examines the vascular and biliary variations in 3035 liver donors. We propose a novel classification of hepatic arteries, portal veins, and bile ducts and clinically relevant donor classification.

METHODS

Preoperative imaging and operative details of 3035 donors from 2005 to 2020 were reviewed. Hilar anatomical variations were identified and grouped on the basis of incidence and clinical relevance.

RESULTS

Hilar structures are classified according to the numbers supplying or draining the graft: for the hepatic artery, right (R) and left (L), RA1/LA1 (1 artery), RA2/LA2 (2 arteries), and RA3/LA3 (3 arteries), respectively, further defined on the basis of the inflow trunk into C (for common hepatic artery), S (for superior mesenteric artery), and L (for left gastric artery); for the portal vein, RP1 (1 vein) and RP2 (2 veins) for the right lobe; and for the hepatic duct, RB1/LB1 (1 duct), RB2/LB2 (2 ducts), RB3 (3 right ducts), and RB4 (4 right ducts). Donors were classified on the basis of anatomical variations into 3 groups: class 1 and class 2 donors, who can donate liver with acceptable risks, and class 3 donors, who are high-risk donors because they are anatomically unacceptable ( Figures S1 to S4, SDC , http://links.lww.com/TP/C918 ).

CONCLUSIONS

Defining hilar anatomical variations and donor grouping into anatomy-based clinical classes helps in operative planning of donors, hepatobiliary surgeries, and interventional procedures.

Unusual grafts for living-donor liver transplantation

PURPOSE

Unusual grafts, including extended left liver plus caudate lobe, right anterior section, and right posterior section grafts, are alternatives to left and right lobe grafts for living-donor liver transplantation. This study aimed to investigate unusual grafts from the perspectives of recipients and donors.

METHODS

From 2016 to 2021, 497 patients received living-donor liver transplantation at Severance Hospital. Among them, 10 patients received unusual grafts. Three patients received extended left liver plus caudate lobe grafts, two patients received right anterior section grafts, and five patients received right posterior section grafts. Liver volumetrics and anatomy were analyzed for all recipients and donors. We collected data on laboratory examinations (alanine aminotransferase, total bilirubin, international normalized ratio), imaging studies, graft survival, and complications. A 1:2 ratio propensity-score matching method was used to reduce selection bias and balance variables between the unusual and conventional graft groups.

RESULTS

The median of Model for End-stage Liver Disease score of unusual graft recipients was 13.5 (interquartile range 11.5-19.3) and that of graft-recipient weight ratio was 0.767 (0.7-0.9). ABO incompatibility was observed in four cases. The alanine aminotransferase level, total bilirubin level, and international normalized ratio decreased in both recipients and donors. Unusual and conventional grafts had similar survival rates (p = 0.492). The right and left subgroups did not differ from each counter-conventional subgroup (p = 0.339 and p = 0.695, respectively). The incidence of major complications was not significantly different between unusual and conventional graft recipients (p = 0.513). Wound seromas were reported by unusual graft donors; the complication ratio was similar to that in conventional graft donors (p = 0.169).

CONCLUSION

Although unusual grafts require a complex indication, they may show feasible surgical outcomes for recipients with an acceptable donor complication.

Preventing Small-for-size Syndrome in Living Donor Liver Transplantation: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference

Small-for-size syndrome (SFSS) is a well-recognized complication following liver transplantation (LT), with up to 20% developing this following living donor LT (LDLT). Preventing SFSS involves consideration of factors before the surgical procedure, including donor and recipient selection, and factors during the surgical procedure, including adequate outflow reconstruction, graft portal inflow modulation, and management of portosystemic shunts. International Liver Transplantation Society, International Living Donor Liver Transplantation Group, and Liver Transplant Society of India Consensus Conference was convened in January 2023 to develop recommendations for the prediction and management of SFSS in LDLT. The format of the conference was based on the Grading of Recommendations, Assessment, Development, and Evaluation system. International experts in this field were allocated to 4 working groups (diagnosis, prevention, anesthesia, and critical care considerations, and management of established SFSS). The working groups prepared evidence-based recommendations to answer-specific questions considering the currently available literature. The working group members, independent panel, and conference attendees served as jury to edit and confirm the final recommendations presented at the end of the conference by each working group separately. This report presents the final statements and evidence-based recommendations provided by working group 2 that can be implemented to prevent SFSS in LDLT patients.

Donor safety of remnant liver volumes of less than 30% in living donor liver transplantation: A systematic review and meta-analysis

PURPOSE

This meta-analysis aimed to investigate the acceptability of donor remnant liver volume (RLV) to total liver volume (TLV) ratio (RLV/TLV) being <30% as safe in living donor liver transplantations (LDLTs).

METHODS

Online databases were searched from January 2000 to June 2022. Pooled odds ratios (ORs) and standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated using fixed- or random-effects model.

RESULTS

One prospective and seven retrospective studies comprising 1935 patients (164 RLV/TLV <30% vs. 1771 RLV/TLV ≥30%) were included. Overall (OR = 1.82; 95% CI [1.24, 2.67]; p = .002) and minor (OR = 1.88; 95% CI [1.23, 2.88]; p = .004) morbidities were significantly lower in the RLV/TLV ≥30% group than in the RLV/TLV <30% group (OR = 1.82; 95% CI [1.24, 2.67]; p = .002). No significant differences were noted in the major morbidity, biliary complications, and hepatic dysfunction. Peak levels of bilirubin (SMD = .50; 95% CI [.07, .93]; p = .02) and international normalized ratio (SMD = .68; 95% CI [.04, 1.32]; p = .04) were significantly lower in the RLV/TLV ≥ 30% group than in the RLV/TLV <30% group. No significant differences were noted in the peak alanine transferase and aspartate transaminase levels and hospital stay.

CONCLUSIONS

Considering the safety of the donor as the top priority, the eligibility of a potential liver donor in LDLT whose RLV/TLV is expected to be <30% should not be accepted.

Subcutaneous Fat Obesity in a High Body Mass Index Donor Is Not a Contraindication to Living Donor Hepatectomy

Background

Living donor liver transplantation (LDLT) has revolutionized the field of transplantation without compromising donor safety. Donor safety is of paramount concern to the transplant team. BMI >35 kg/m2 is mostly considered a contraindication to liver donation. Here, we present a successful right donor hepatectomy from a donor with a BMI of 36.5 kg/m2. Case Summary. A 39-year-old wife donated her right lobe of liver to her 43-year-old husband with nonalcoholic steatohepatitis-related chronic liver disease (CLD). His indications were refractory ascites, hepatic encephalopathy, acute kidney injury, recurrent elbow and urine infections leading to cachexia. She was initially rejected due to a high BMI but failed to lose weight over the next 2 months, and the need for a transplant in her husband was imminent. With no other potential living donors, we decided to proceed with donor evaluation as she had no other comorbidity. We were surprised to find normal liver function tests and a good liver attenuation index (LAI) of +16 on a computed tomography (CT) scan. Magnetic resonance (MR) imaging revealed a fat fraction of 3%. Volumetry confirmed a remnant of 37.9% and a potential graft-to-recipient weight ratio of 1.23. V/S ratio on CT scan (visceral fat area/subcutaneous fat area at L4-level) was <0.4 confirming subcutaneous fat obesity. Both surgeries were uneventful and both donor and recipient recovered well except recipient re-exploration on postoperative day (POD)-1 due to surgical bleeding. The donor was discharged on POD-6 and recipient was discharged on POD-15. At 3 weeks of follow-up, the donor's wound is clean and well-healed, and she is already back to doing her daily life activities without any pain with normal laboratory parameters.

Conclusion

Subcutaneous fat obesity should not be considered as a contraindication to liver donation even with a BMI >35 kg/m2. A small percentage of healthy individuals will not have visceral fat obesity and may not have steatotic livers. The CT scan and MR fat fraction estimation can confirm the findings. Biopsy may be avoided if MR fat estimation is <10% in obese donors. Intraoperative visualization in these donors remains the gold standard to decide the need for biopsy. Living donor hepatectomy may be safely performed in a select group of high BMI patients (>35 kg/m2) with pure subcutaneous fat obesity in the absence of other suitable living donors.

The role of Roux-en-Y hepaticojejunostomy for the management of biliary complications after living donor liver transplantation

INTRODUCTION

Post living donor liver transplantation (LDLT) biliary complications can be troublesome over the post-operative course of patients, especially those with recurrent cholangitis or choledocholithiasis. Thus, in this study, we aimed to evaluate the risks and benefits of Roux-en-Y hepaticojejunostomy (RYHJ) performed after LDLT as a last option to deal with post-LDLT biliary complications.

METHODS

Retrospectively, of the 594 adult LDLTs performed in a single medical center in Changhua, Taiwan from July 2005 to September 2021, 22 patients underwent post-LDLT RYHJ. Indications for RYHJ included choledocholithiasis formation with bile duct stricture, previous intervention failure, and other factors. Restenosis was defined if further intervention was needed to treat biliary complications after RYHJ was performed. Thereafter, patients were categorized into success group (n = 15) and restenosis group (n = 4).

RESULTS

The overall success rate of RYHJ in the management of post-LDLT biliary complications was 78.9% (15/19). Mean follow-up time was 33.4 months. As per our findings, four patients experienced recurrence after RYHJ (21.2%), and mean recurrence time was 12.5 months. Three cases were recorded as hospital mortality (13.6%). Outcome and risk analysis presented no significant differences between the two groups. A higher risk of recurrence tended to be related to patients with ABO incompatible (ABOi).

CONCLUSION

RYHJ served well as either a rescue but definite procedure for recurrent biliary complications or a safe and effective solution to biliary complications after LDLT. A higher risk of recurrence tended to be related to patients with ABOi; however, further research would be needed.

A survey of transplant providers regarding attitudes, barriers, and facilitators to living donor liver transplantation in the United States

INTRODUCTION

A successful living donor liver transplant (LDLT) is the culmination of a multifaceted process coordinated among key stakeholders.

METHODS

We conducted an electronic survey of US liver transplant (LT) centers (August 26, 2021-October 10, 2021) regarding attitudes, barriers, and facilitators of LDLT to learn how to expand LDLT safely and effectively in preparation for the American Society of Transplantation Living Donor Liver Transplant Consensus Conference.

RESULTS

Responses were received from staff at 58 programs (40.1% of US LT centers). There is interest in broadening LDLT (100% of LDLT centers, 66.7% of non-LDLT centers) with high level of agreement that LDLT mitigates donor shortage (93.3% of respondents) and that it should be offered to all suitable candidates (87.5% of respondents), though LDLT was less often endorsed as the best first option (29.5% of respondents). Key barriers at non-LDLT centers were institutional factors and surgical expertise, whereas those at LDLT centers focused on waitlist candidate and donor factors. Heterogeneity in candidate selection for LDLT, candidate reluctance to pursue LDLT, high donor exclusion rate, and disparities in access were important barriers.

CONCLUSION

Findings from this study may help guide current and future expansion of LDLT more efficiently in the US. These efforts require clear and cohesive messaging regarding LDLT benefits, engagement of the public community, and dedicated resources to equitably increase LDLT access.

Living donor liver transplant candidate and donor selection and engagement: Meeting report from the living donor liver transplant consensus conference

INTRODUCTION

Living donor liver transplantation (LDLT) is a promising option for mitigating the deceased donor organ shortage and reducing waitlist mortality. Despite excellent outcomes and data supporting expanding candidate indications for LDLT, broader uptake throughout the United States has yet to occur.

METHODS

In response to this, the American Society of Transplantation hosted a virtual consensus conference (October 18-19, 2021), bringing together relevant experts with the aim of identifying barriers to broader implementation and making recommendations regarding strategies to address these barriers. In this report, we summarize the findings relevant to the selection and engagement of both the LDLT candidate and living donor. Utilizing a modified Delphi approach, barrier and strategy statements were developed, refined, and voted on for overall barrier importance and potential impact and feasibility of the strategy to address said barrier.

RESULTS

Barriers identified fell into three general categories: 1) awareness, acceptance, and engagement across patients (potential candidates and donors), providers, and institutions, 2) data gaps and lack of standardization in candidate and donor selection, and 3) data gaps regarding post-living liver donation outcomes and resource needs.

CONCLUSIONS

Strategies to address barriers included efforts toward education and engagement across populations, rigorous and collaborative research, and institutional commitment and resources.

Living donor liver transplantation: A multi-disciplinary collaboration towards growth, consensus, and a change in culture

INTRODUCTION

Living donor liver transplantation (LDLT) reduces liver transplant waitlist mortality and provides excellent long-term outcomes for persons with end stage liver disease. Yet, utilization of LDLT has been limited in the United States (US).

METHODS

In October 2021, the American Society of Transplantation held a consensus conference to identify important barriers to broader expansion of LDLT in the US, including data gaps, and make recommendations for impactful and feasible mitigation strategies to overcome these barriers. Domains addressed encompassed the entirety of the LDLT process. Representation from international centers and living donor kidney transplantation were included for their perspective/experience in addition to members across disciplines within the US liver transplantation community. A modified Delphi approach was employed as the consensus methodology.

RESULTS

The predominant theme permeating discussion and polling results centered on culture; the beliefs and behaviors of a group of people perpetuated over time.

CONCLUSIONS

Creating a culture of support for LDLT in the US is key for expansion and includes engagement and education of stakeholders across the spectrum of the process of LDLT. A shift from awareness of LDLT to acknowledgement of benefit of LDLT is the primary goal. Propagation of the maxim "LDLT is the best option" is pivotal.

High-resolution MR imaging with gadoxetate disodium for the comprehensive evaluation of potential living liver donors

OBJECTIVE

Several major transplantation centers have used composite multimodality evaluation for the preoperative evaluation of potential living liver donors. This approach can be time-consuming and, although rare, can cause complications. We aimed to demonstrate the clinical feasibility of our comprehensive preoperative MR protocol for the preoperative assessment of living liver donor candidates instead of composite multimodality evaluation.

MATERIALS AND METHODS

Thirty-five consecutive living liver donor candidates underwent multiphasic liver CT and comprehensive donor protocol MR examinations for preoperative evaluation in a single large-volume liver transplantation (LT) center. Three blinded abdominal radiologists reviewed the CT and MR images for vascular and biliary variations. The strength of agreement between CT and MR angiography was assessed using the kappa index. The detection rate of biliary anatomical variations was calculated. The sensitivity and specificity for detecting significant steatosis (>5%) were calculated. The estimated total volume and right lobe volumes measured by MR volumetry were compared with the corresponding CT volumetry measurements using the intraclass correlation coefficient (ICC).

RESULTS

Among the 35 patients, 26 underwent LT. The measurement of agreement showed a moderate to substantial agreement between CT and MR angiography interpretations (kappa values, 0.47-0.79; p < 0.001). Combining T2-weighted and T1-weighted MR cholangiography techniques detected all biliary anatomical variations in 9 of the 26 patients. MR-proton density fat fraction showed a sensitivity of 100% (3/3) and a specificity of 91.3% (21/23) for detecting pathologically determined steatosis (>5%). MR volumetry reached an excellent agreement with CT volumetry (reviewers 1 and 2: ICC, 0.92; 95% CI, 0.84-0.96).

CONCLUSION

Our one-stop comprehensive liver donor MR imaging protocol can provide complete information regarding hepatic vascular and biliary anatomies, hepatic parenchymal quality, and liver volume for living liver donor candidates and can replace composite multimodality evaluation.

Practice patterns of the medical evaluation of living liver donors in the United States

Living donor liver transplantation (LDLT) can help address the growing organ shortage in the United States, yet little is known about the current practice patterns in the medical evaluation of living liver donors. We conducted a 131-question survey of all 53 active LDLT transplant programs in the United States to assess current LDLT practices. The response rate was 100%. Donor acceptance rate was 0.33 with an interquartile range of 0.33-0.54 across all centers. Areas of high intercenter agreement included minimum age cutoff of 18 years (73.6%) and the exclusion of those with greater than Class 1 obesity (body mass index, 30.0-34.9 m/kg 2 ) (88.4%). Diabetes mellitus was not an absolute exclusion at most centers (61.5%). Selective liver biopsies were performed for steatosis or iron overload on imaging (67.9% and 62.3%, respectively) or for elevated liver enzymes (60.4%). Steatohepatitis is considered an exclusion at most centers (84.9%). The most common hypercoagulable tests performed were factor V Leiden (FVL) (88.5%), protein C (73.1%), protein S (71.2%), antithrombin III (71.2%) and prothrombin gene mutation (65.4%). At 41.5% of centers, donors were allowed to proceed with donation with FVL heterozygote status. Most programs discontinue oral contraceptive pills at least 28 days prior to surgery. At most centers, the need for cardiovascular ischemic risk testing is based on age (73.6%) and the presence of one or more cardiac risk factors (68.0%). Defining areas of practice consensus and variation underscores the need for data generation to develop evidence-based guidance for the evaluation and risk assessment of living liver donors.

Low utilization of adult-to-adult LDLT in Western countries despite excellent outcomes: International multicenter analysis of the US, the UK, and Canada

BACKGROUND & AIMS

Adult-to-adult living donor liver transplantation (LDLT) offers an opportunity to decrease the liver transplant waitlist and reduce waitlist mortality. We sought to compare donor and recipient characteristics and post-transplant outcomes after LDLT in the US, the UK, and Canada.

METHODS

This is a retrospective multicenter cohort-study of adults (≥18-years) who underwent primary LDLT between Jan-2008 and Dec-2018 from three national liver transplantation registries: United Network for Organ Sharing (US), National Health Service Blood and Transplantation (UK), and the Canadian Organ Replacement Registry (Canada). Patients undergoing retransplantation or multi-organ transplantation were excluded. Post-transplant survival was evaluated using the Kaplan-Meier method, and multivariable adjustments were performed using Cox proportional-hazards models with mixed-effect modeling.

RESULTS

A total of 2,954 living donor liver transplants were performed (US: n = 2,328; Canada: n = 529; UK: n = 97). Canada has maintained the highest proportion of LDLT utilization over time (proportion of LDLT in 2008 - US: 3.3%; Canada: 19.5%; UK: 1.7%; p <0.001 - in 2018 - US: 5.0%; Canada: 13.6%; UK: 0.4%; p <0.001). The 1-, 5-, and 10-year patient survival was 92.6%, 82.8%, and 70.0% in the US vs. 96.1%, 89.9%, and 82.2% in Canada vs. 91.4%, 85.4%, and 66.7% in the UK. After adjustment for characteristics of donors, recipients, transplant year, and treating transplant center as a random effect, all countries had a non-statistically significantly different mortality hazard post-LDLT (Ref US: Canada hazard ratio 0.53, 95% CI 0.28-1.01, p = 0.05; UK hazard ratio 1.09, 95% CI 0.59-2.02, p = 0.78).

CONCLUSIONS

The use of LDLT has remained low in the US, the UK and Canada. Despite this, long-term survival is excellent. Continued efforts to increase LDLT utilization in these countries may be warranted due to the growing waitlist and differences in allocation that may disadvantage patients currently awaiting liver transplantation.

LAY SUMMARY

This multicenter international comparative analysis of living donor liver transplantation in the United States, the United Kingdom, and Canada demonstrates that despite low use of the procedure, the long-term outcomes are excellent. In addition, the mortality risk is not statistically significantly different between the evaluated countries. However, the incidence and risk of retransplantation differs between the countries, being the highest in the United Kingdom and lowest in the United States.

Liver Paired Exchange: Programmatic Hopes and Fears

The dearth of deceased liver donors has created a supply demand gap, necessitating creation of living donor liver transplantation. However, living donor liver transplantation has relied on directed donation, whereby many potential directed donors are rejected based on ABO blood group incompatibility, hepatic size incompatibility, or the need for biliary or arterial reconstruction during transplant surgery. Much like kidney paired exchange, liver paired exchange (LPE) circumvents these incompatibility issues by relying on anonymous, nondirected, or bridge donors that are better anatomical or histological matches for recipients. Although Asia has taken the lead in LPE, the process has only recently been adopted in North America, with the first successful surgery done in the United States in 2019. Our review article sheds light on the process of LPE and the success of LPE in the United States thus far and, additionally, highlights the several logistical and ethical challenges that must be considered as transplant centers adopt and scale up LPE across the United States to address the increased demand for liver allografts.

Regional and National Trends of Adult Living Donor Liver Transplantation in the United States Over the Last Two Decades

BACKGROUND AND AIMS

Liver organ shortage remains a major health burden in the US, with more patients being waitlisted than the number of liver transplants (LTs) performed. This study investigated US national and regional trends in living donor LT (LDLT) and identified factors associated with recipient survival.

METHODS

We retrospectively analyzed LDLT recipients and donors from the United Network Organ Sharing/Organ Procurement Transplant Network database from 1998 until 2019 for clinical characteristics, demographic differences, and survival rate. National and regional trends in LDLT, recipient outcomes, and predictors of survival were analyzed.

RESULTS

Of the 223,571 candidates listed for an LT, 57.5% received an organ, of which only 4.2% were LDLTs. Annual adult LDLTs first peaked at 412 in 2001 but experienced a significant decline to 168 by 2009. LDLTs then gradually increased to 445 in 2019. Region 2 had the highest LDLT numbers (n=919), while region 1 had the highest proportion (11.1%). Overall, post-LT mortality was 21.4% among LDLT recipients. Post-LDLT survival rates after 1-, 5-, and 10-years were 92%, 87%, and 70%, respectively. Interval analysis (2004-2019) showed that patients undergoing LDLT in recent years had lower mortality than in earlier years (hazard ratio=0.81, 95% confidence interval=0.75-0.88).

CONCLUSIONS

Following a substantial decline after a peak in 2001, the number of adult LDLTs steadily increased from 2011 to 2019. However, LDLTs still constitute the minority of the transplant pool in the US. Life-saving policies to increase the use of LDLTs, particularly in regions of high organ demand, should be implemented.

The role of graft to recipient weight ratio on enhanced recovery of the recipient after living donor liver transplantation - A systematic review of the literature and expert panel recommendations

BACKGROUND

There continues to be debate about the lower limit of graft-to-recipient weight ratio (GRWR) for living donor liver transplant (LDLT).

OBJECTIVES

To identify the lower limit of GRWR compatible with enhanced recovery after living donor liver transplant and to provide international expert panel recommendations.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central.

METHODS

Systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel. Studies assessing how GRWR affects recipient outcomes such as small for size syndrome, other complications, patient and graft survival, and length of stay were included.

PROTOCOL REGISTRATION

CRD42021260794.

RESULTS

Twenty articles were included in the qualitative synthesis, and all were retrospective observational studies. There was heterogeneity in the definition of study cohorts and key outcome measures such as small-for-size syndrome. Most studies lacked risk adjustment given limited single-center sample size. GRWR of ≥ .8% is associated with enhanced recovery. Recipients of grafts with GRWR < .8%, however, were found to have similar outcomes as those with ≥ .8% when appropriate consideration is made for portal flow modulation and recipient illness severity.

CONCLUSIONS

GRWR ≥ .8% is often compatible with enhanced recovery, but grafts < .8% can be used in selected LDLT recipients with optimal donor-recipient selection, surgical technique, and perioperative management (Quality of Evidence; Low | Grade of Recommendation; Strong).

Expanding the living liver donor pool in countries having limited deceased donor activity: Pakistani perspective

Over the last decades, liver transplantation (LT) has evolved into a life-saving procedure. Due to limited deceased donor activities in the eastern world, living donor liver transplantation (LDLT) had flourished tremendously in most Asian countries. Yet, these LDLT activities fall short of meeting the expected demands. Pakistan, a developing country, bears a major burden of liver diseases. Currently, only few centers offer LDLT services in the country. On the other hand, deceased donor liver transplantation (DDLT) activities have not started due to social, cultural, and religious beliefs. Various strategies can be adopted successfully to overcome the scarcity of live liver donors (LLDs) and to expand the donor pool, keeping in view donor safety and recipient outcome. These include consideration of LLDs with underlying clinical conditions like G6PD deficiency and Hepatitis B core positivity. Extended donor criteria can also be utilized and relaxation can be made in various donors' parameters including upper age and body mass index after approval from the multidisciplinary board. Also, left lobe grafts, grafts with various anatomical variations, and a low graft-to-recipient ratio can be considered in appropriate situations. ABO-incompatible LT and donor swapping at times may help in expanding the LLDs pool. Similarly, legislation is needed to allow live non-blood-related donors for organ donations. Finally, community education and awareness through various social media flat forms are needed to promote deceased organ donation.

Identification of hepatic steatosis in living liver donors by machine learning models

Selecting an optimal donor for living donor liver transplantation is crucial for the safety of both the donor and recipient, and hepatic steatosis is an important consideration. We aimed to build a prediction model with noninvasive variables to evaluate macrovesicular steatosis in potential donors by using various prediction models. The study population comprised potential living donors who had undergone donation workup, including percutaneous liver biopsy, in the Republic of Korea between 2016 and 2019. Meaningful macrovesicular hepatic steatosis was defined as >5%. Whole data were divided into training (70.5%) and test (29.5%) data sets based on the date of liver biopsy. Random forest, support vector machine, regularized discriminant analysis, mixture discriminant analysis, flexible discriminant analysis, and deep neural network machine learning methods as well as traditional logistic regression were employed. The mean patient age was 31.4 years, and 66.3% of the patients were men. Of the 1652 patients, 518 (31.4%) had >5% macrovesicular steatosis on the liver biopsy specimen. The logistic model had the best prediction power and prediction performances with an accuracy of 80.0% and 80.9% in the training and test data sets, respectively. A cut-off value of 31.1% for the predicted risk of hepatic steatosis was selected with a sensitivity of 77.7% and specificity of 81.0%. We have provided our model on the website (https://hanseungbong.shinyapps.io/shiny_app_up/) under the name DONATION Model. Our algorithm to predict macrovesicular steatosis using routine parameters is beneficial for identifying optimal potential living donors by avoiding superfluous liver biopsy results.

Practices and Perceptions of Living Donor Liver Transplantation, Nondirected Donation, and Liver Paired Exchange: A National Survey

Living donor liver transplantation (LDLT) remains underutilized in the United States. Barriers to LDLT and acceptance of nondirected living liver donation (ND-LLD) and liver paired exchange (LPE) are unclear. The medical and surgical directors of 99 unique transplantation programs (56 LDLT programs and 43 non-LDLT programs) were surveyed to gain insight into perceptions and practices of LDLT and types of donors utilized. The response rate was 84%. Most LDLT programs (65%) reported performing ND-LLD, though opinions regarding allocation and the need for additional evaluation of these donors were mixed. Only a minority of LDLT programs reported performing LPE (12%), but most programs (78%) would be open to cross-institutional LPE barring logistical barriers. There were significant differences between LDLT and non-LDLT programs with regard to perceived barriers to LDLT, with LDLT programs reporting mainly donor and recipient factors and non-LDLT programs reporting institutional factors (P < 0.001). Understanding perceptions and practices of LDLT, ND-LLD, and LPE is important to aid in the growth of LDLT.

Safety, clinical and laboratory characteristics of donors with thalassemia minor in living donor kidney transplant: a case series

Background

Due to the increasing demand for kidney transplants, sometimes donors with underlying medical conditions can be considered for living kidney donor transplant. Thalassemia is amongst the most common inherited disorders of hemoglobin globally, which is not restricted as an exclusion criterion. However, there is currently no study examine the safety and characteristics of kidney donors with thalassemia minor.

Methods

All eligible live kidney donors between 2016 and 2019 with thalassemia minor at a tertiary hospital were recruited. Baseline characteristics, clinical and laboratory outcomes were investigated.

Results

Fifteen donors (11 women, 55.5 ± 15.0 year-old) were included with a follow-up duration of 2 (1-4) years since operation. The most prevalent gene mutation among participants was DEL-SEA. No clinical manifestations of anemia were seen but 10 participants had mild anemia diagnosed from blood tests. Cardiovascular, liver and renal function were normal before nephrectomy. Until now, all donors are alive and maintain overall good health. Anemia condition is not affected, and the post-donation eGFR = 71.04 ± 11.54 mL/min/1.73m² is comparable to outcomes of healthy donors reported in previous studies. Two donors are at risk of proteinuria at 1-year post-transplant with A/C ratio > 30 mg/g.

Conclusions

Thalassemia minor individuals who are non-transfusion-dependent, without anemia clinical manifestations and have no contraindications to kidney donation are safe to be donors in short-term. An eGFR of at least 80 mL/min/1.73m² should be considered to avoid low post-donation eGFR, and awareness should be raised on thalassemia donors with even mild albuminuria. Nephrectomy does not worsen thalassemia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02609-2.

Outcomes of Highly Selected Live Donors With a Future Liver Remnant Less Than or Equal to 30%: A Matched Cohort Study

BACKGROUND

The main concern with live donor liver transplantation (LDLT) is the risk to the donor. Given the potential risk of liver insufficiency, most centers will only accept candidates with future liver remnants (FLR) >30%. We aimed to compare postoperative outcomes of donors who underwent LDLT with FLR ≤30% and >30%.

METHODS

Adults who underwent right hepatectomy for LDLT between 2000 and 2018 were analyzed. Remnant liver volumes were estimated using hepatic volumetry. To adjust for between-group differences, donors with FLR ≤30% and >30% were matched 1:2 based on baseline characteristics. Postoperative complications including liver dysfunction were compared between the groups.

RESULTS

A total of 604 live donors were identified, 28 (4.6%) of whom had a FLR ≤30%. Twenty-eight cases were successfully matched with 56 controls; the matched cohorts were mostly similar in terms of donor and graft characteristics. The calculated median FLR was 29.8 (range, 28.0-30.0) and 35.2 (range, 30.1-68.1) in each respective group. Median follow-up was 36.5 mo (interquartile range, 11.8-66.1). Postoperative outcomes were similar between groups. No difference was observed in overall complication rates (FLR ≤30%: 32.1% versus FLR >30%: 28.6%; odds ratio [OR], 1.22; 95% confidence interval [CI], 0.46-3.27) or major complication rates (FLR ≤30%: 14.3% versus FLR >30%: 14.3%; OR, 1.17; 95% CI, 0.33-4.10). Posthepatectomy liver failure was rare, and no difference was observed (FLR ≤30%: 3.6% versus FLR >30%: 3.6%; OR, 1.09; 95% CI, 0.11-11.1).

CONCLUSION

A calculated FLR between 28% and 30% on its own should not represent a formal contraindication for live donation.

Imaging Evaluation of Living Liver Donor Candidates: Techniques, Protocols, and Anatomy

The need for liver transplants is increasing because the prevalence of liver diseases and the indications for transplants are growing. In response to the shortage of grafts from deceased donors, more transplants are being performed worldwide with grafts from living donors. Radiologic evaluation is an integral component in the assessment of donor candidates to ensure their eligibility and to choose the most appropriate surgical approach. MRI is the preferred modality for evaluation of the liver parenchyma and biliary tree. In most centers, a combination of MRI and CT is used to take advantage of the higher spatial resolution of CT for evaluation of arteries. However, MRI-only assessment is feasible. In addition to assessment of the liver parenchyma for abnormalities such as steatosis, a detailed evaluation of the hepatic vascular and biliary system for pertinent anatomic variants is crucial, because these variants can affect surgical techniques and outcomes in both recipients and donors. In this pictorial article, after a brief review of the most common surgical techniques and postsurgical liver anatomy, the biliary and vascular anatomy are discussed, with specific attention paid to the variants that are pertinent to this surgical procedure. The roles of liver segmentation and volumetric assessment and current imaging techniques and protocols are also discussed. Online supplemental material is available for this article. ©RSNA, 2021.

Fatty liver disease in Living Liver Donors: A Single-Institute Experience of 220 Donors

We retrospectively reviewed 220 living liver donors, with a focus on the development of postoperative fatty liver. Data regarding demographics, comorbidities, imaging tests, operations, and biopsies were obtained from medical records. We used unenhanced CT and USG to diagnose fatty liver. Donor candidates with fatty liver underwent weight loss intervention until imaging tests no longer demonstrated any features of fatty liver. Among 220 donors, 61 were diagnosed with preoperative fatty liver. The mean BMI of these 61 donors significantly decreased from 24.9 at the first visit to 23.6 kg/m² immediately before surgery (p=0.0386). A multivariate analysis revealed the following significant risk factors for postoperative fatty liver: male sex (p=0.0033), BMI immediately before surgery (p=0.0028), and a history of treatment for preoperative fatty liver (p=0.0231). Postoperative fatty liver was often refractory to weight loss intervention. No improvement was observed in 14 of the 32 donors who had been diagnosed with fatty liver postoperatively, and 1 of the 14 donors even developed NASH. In conclusion, special attention should be paid to prevent fatty liver after surgery in male donors who show a high BMI immediately before surgery and with a history of treatment for preoperative fatty liver, and lifelong follow-up is recommended.

Assessment of the global practice of living donor liver transplantation

Criteria that drive the selection and utilization of living liver donors are limited. Herein, the global availability of living donor liver transplantation (LDLT) and components of donor selection and utilization were assessed via an international survey. There were 124 respondents representing 41 countries, including 47 from Asia/Middle East (A/ME), 20 from Europe, and 57 from the Americas. Responses were obtained from 94.9% of countries with ≥10 LDLT cases/year. Most centers (82.3%) have defined donor age criteria (median 18-60 years), while preset recipient MELD cutoffs (median 18-30) were only reported in 54.8% of programs. Overall, 67.5% of programs have preset donor BMI (body mass index) ranges (median 18-30), and the mean acceptable macrosteatosis was highest for A/ME (20.2 ± 9.2%) and lowest for Americas (16.5 ± 8.4%, P = 0.04). Americas (56.1%) and European (60.0%) programs were more likely to consider anonymous donors versus A/ME programs (27.7%, P = 0.01). There were no differences in consideration of complex anatomical variations. Most programs (75.9%) perform donor surgery via an open approach, and A/ME programs are more likely to use microscopic arterial reconstruction. Despite variations in practice, key aspects of living donor selection were identified. These findings provide a contemporary reference point as LDLT continues to expand into areas with limited access to liver transplantation.

Which is better to use "body weight" or "standard liver weight", for predicting small-for-size graft syndrome after living donor liver transplantation?

AIM

Little evidence about whether to apply graft-to-recipient body weight ratio (GRWR) or graft weight to standard liver weight (GW/SLW) for graft selection has been published. The aim of the present study was to clarify the importance of the correct use of GRWR and GW/SLW for selecting graft according to the recipients' physique in living donor liver transplantation (LDLT).

METHODS

Data were collected for 694 recipients who underwent LDLT between 1997 and 2020.

RESULTS

One of the marginal grafts meeting GW/SLW ≥ 35% but GRWR < 0.7% has been used in more recipients with men and higher body mass index (BMI), and the other meeting GRWR ≥ 0.7% but GW/SLW < 35% has been used in more recipients with women with lower BMI. In the cohort of BMI > 30 kg/m2, the recipients with GRWR < 0.7% had a significantly higher incidence of small-for-size graft syndrome (SFSS) compared to those with GRWR ≥ 0.7% (P = 0.008, 46.2% vs 5.9%), and using the cutoff of GW/SLW < 35% could not differentiate. In contrast, in the cohort of BMI ≤ 30 kg/m2, the recipients with GW/SLW < 35% also had a significantly higher incidence of SFSS (P = 0.013, 16.9% vs 9.4%). Multivariate analysis showed that GRWR < 0.7% [odds ratio (OR) 14.145, P = 0.048] was the independent risk factor for SFSS in obese recipients, and GW/SLW < 35% [OR 2.685, P = 0.002] was the independent risk factor in non-obese recipients.

CONCLUSION

Proper use of the formulas for calculating GRWR and GW/SLW in choosing graft according to recipient BMI is important, not only to meet metabolic demand for avoiding SFSS but also to ameliorate donor shortages.

Safe use of right lobe living donor livers with moderate steatosis in adult-to-adult living donor liver transplantation: a retrospective study

Hepatic steatosis (HS) beyond a certain degree can jeopardize living donor (LD) safety, particularly in right lobe (RL) donors, making it a major obstacle for donor pool expansion in adult-to-adult living donor liver transplantation (ALDLT). From July 2004 to June 2016, 58 LDs donated their RLs despite having moderate HS (30%-50% steatosis) determined by intraoperative biopsy at a single center. We performed greedy matching to compare the outcomes of the donors and recipients of this group with those of LDs with no HS. The mean left lobe (LL) HS value in the 58 cases was 20.9 ± 12.4%, which was significantly lower than the mean RL HS value (38.8 ± 6.7%, P < 0.001). The mean ratio of the remnant LL to the total liver volume was 37.8 ± 2.2. No differences were observed in the postoperative liver function and donor and recipient morbidity and mortality rates. The liver regeneration rates in recipients and donors at 1 month, 6 months, and 1 year postoperatively did not differ significantly. The patient and graft survival rates of the recipients showed no differences. The use of well-selected RL grafts with moderate steatosis does not impair graft function, recipient outcomes, or donor safety.

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.

Living-donor liver transplantation: Right versus left

A dilemma of graft selection between right or left livers occurs during the planning of living-donor liver transplantation (LDLT) as well as splitting a whole liver graft into full right/full left grafts in deceased-donor liver transplantation. The right liver's relation to the whole liver could be considered as the trunk of a tree; it has a larger volume, the main axis of bile ducts, and the inferior vena cava mainly belongs to the right liver. Therefore, it was considered as the standard graft in LDLTs. Whether to procure the middle hepatic vein (MHV) with a right liver graft or to leave it attached to the left-liver remnant largely depends on the transplant institute. Recently, most transplant institutes tend to leave the MHV with the left liver for the sake of donor safety. Unlike hepatectomy for liver tumors, it is vital to preserve inflow and outflow for both the resected as well as the remaining livers. While procuring any graft type, the most important is to procure a liver graft with reconstructable portal veins, hepatic arteries, hepatic veins, and bile ducts, which should be well preoperatively planned using 3D-computed tomography with considerations given to graft volume and potential congestion areas.

SHMT2 Promotes Liver Regeneration Through Glycine-activated Akt/mTOR Pathway

BACKGROUND

The development of liver transplantation (LT) is increasingly being limited by the unavailability of liver grafts. Unique regenerative capacity of liver in response to injuries makes living-donor liver transplantation (LDLT) a feasible strategy to meet clinical demands. Serine hydroxymethyl-transferase 2 (SHMT2) serves as the key enzyme in the biosynthesis of glycine. Glycine affects the activity of mammalian target of rapamycin (mTOR), which is important for cellular growth and proliferation. In this study, the effects of SHMT2 on mouse liver regeneration were investigated using a classical partial hepatectomy (PH) model.

METHODS

In vivo, PH was performed on mice with or without knockdown of SHMT2. In vitro, SHMT2 was overexpressed in primary hepatocytes, which were cultured in customized Dulbecco's modified eagle media and LY294002 (an Akt inhibitor). Relevant indexes of liver regeneration, cell proliferation, and Akt/mTOR signal pathways were analyzed.

RESULTS

After PH, the expression levels of SHMT2 fluctuated with time and knockdown of SHMT2 in vivo lowered the regenerative ability of liver, with reduced glycine levels compared to the scramble group. In addition, overexpression of SHMT2 in hepatocytes boosted glycine production while enhancing Akt/mTOR pathway activity. These results were validated by the application of LY294002 in vitro.

CONCLUSIONS

SHMT2 can contribute to liver regeneration after PH, and this is likely related to the activation of Akt/mTOR signaling pathway by its metabolic product, glycine, in hepatocytes. These results might have therapeutic implications for the prognosis of patients undergoing hepatic resection or transplantation.

Body Mass Index and Unenhanced CT as a Predictor of Hepatic Steatosis in Potential Liver Donors

BACKGROUND

In living-donor liver transplantation, donor hepatic steatosis is crucial for both the donor and the recipient. Body mass index (BMI) and the unenhanced computed tomography liver attenuation index (CT LAI) are noninvasive methods to predict hepatic steatosis in living-donor liver candidates.

AIM

To analyze the diagnostic accuracy of CT LAI in conjunction with different BMI values for macrovesicular steatosis in living-donor liver candidates.

METHODS

A total of 264 potential liver donors were included. The diagnostic accuracy of 2 CT LAI cut-offs and 3 BMI cut-off values for the assessment of hepatic steatosis ≥15% and ≤5% was determined.

RESULTS

Using CT LAI, the area under the receiver operating characteristic curve was 0.97 (95% CI = 0.89-0.99) for hepatic steatosis ≥15% in donors with BMI <25 kg/m². For detecting hepatic steatosis ≥15%, a CT LAI ≤0 had specificities of 100%, 76.2%, and 55.6% and positive predictive values of 100%, 95.5%, and 93.5% for patients with BMI values <25 kg/m², 25 to 29.9 kg/m², and ≥30 kg/m², respectively. According to logistic regression analyses, only CT LAI ≤0 was found to be independently associated with hepatic steatosis ≥15%.

CONCLUSIONS

In donors with BMI <30 kg/m² and a CT LAI value >6, liver biopsy might be avoided. Biopsy may be reserved solely for donors with CT LAI value >0 and BMI ≥30 kg/m² as the diagnostic accuracy of computed tomography for predicting hepatic steatosis decreases with increasing BMI.

Living Donor Liver Transplantation: Overview, Imaging Technique, and Diagnostic Considerations

OBJECTIVE. The purpose of this article is to discuss the process of becoming a liver donor, describe the surgical methods used for transplantation, and critically review preoperative and intraoperative imaging techniques. CONCLUSION. Radiologists play a vital role in ensuring the safety of living liver donors; however, consensus guidelines do not exist for imaging protocol or reporting. Standardization would provide more consistent image quality across centers, improve communication with the transplant team, and facilitate data mining for quality assurance and research.