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

Temporal evolution of living donor liver transplantation survival-A United Network for Organ Sharing registry study

Living donor liver transplantation (LDLT) is a curative treatment for various liver diseases, reducing waitlist times and associated mortality. We aimed to assess the overall survival (OS), identify predictors for mortality, and analyze differences in risk factors over time. Adult patients undergoing LDLT were selected from the United Network for Organ Sharing database from inception (1987) to 2023. The Kaplan-Meier method was used for analysis, and multivariable Cox proportional hazard models were conducted. In total, 7257 LDLT recipients with a median age of 54 years (interquartile range [IQR]: 45-61 years), 54% male, 80% non-Hispanic White, body mass index of 26.3 kg/m2 (IQR: 23.2-30.0 kg/m2), and model for end-stage liver disease score of 15 (IQR: 11-19) were included. The median cold ischemic time was 1.6 hours (IQR: 1.0-2.3 hours) with 88% right lobe grafts. The follow-up was 4.0 years (IQR: 1.0-9.2 years). The contemporary reached median OS was 17.0 years (95% CI: 16.1, 18.1 years), with the following OS estimates: 1 year 95%; 3 years 89%; 5 years 84%; 10 years 72%; 15 years 56%; and 20 years 43%. Nine independent factors associated with mortality were identified, with an independent improved OS in the recent time era (adjusted hazards ratio: 0.53; 95% CI: 0.39, 0.71). The median center-caseload per year was 5 (IQR: 2-10), with observed center-specific improvement of OS. LDLT is a safe procedure with excellent OS. Its efficacy has improved despite an increase of risk parameters, suggesting its limits are yet to be met.

EASL Clinical Practice Guidelines on the management of hepatocellular carcinoma

Liver cancer is the third leading cause of cancer-related deaths worldwide, with hepatocellular carcinoma (HCC) accounting for approximately 90% of primary liver cancers. Advances in diagnostic and therapeutic tools, along with improved understanding of their application, are transforming patient treatment. Integrating these innovations into clinical practice presents challenges and necessitates guidance. These clinical practice guidelines offer updated advice for managing patients with HCC and provide a comprehensive review of pertinent data. Key updates from the 2018 EASL guidelines include personalised surveillance based on individual risk assessment and the use of new tools, standardisation of liver imaging procedures and diagnostic criteria, use of minimally invasive surgery in complex cases together with updates on the integrated role of liver transplantation, transitions between surgical, locoregional, and systemic therapies, the role of radiation therapies, and the use of combination immunotherapies at various stages of disease. Above all, there is an absolute need for a multiparametric assessment of individual risks and benefits, considering the patient's perspective, by a multidisciplinary team encompassing various specialties.

Comparison of Clinical Outcomes Using Left and Right Liver Grafts in Adult-to-adult Living-donor Liver Transplantation: A Retrospective Cohort Study Using the Korean Organ Transplantation Registry

BACKGROUND

Living-donor liver transplantation has been widely performed as an alternative to the scarce liver grafts from deceased donors. More studies are reporting favorable outcomes of left liver graft (LLG). This study compared the clinical outcomes between living-donor liver transplantation using LLG and right liver graft (RLG) with similar graft-to-recipient body weight ratios.

METHODS

This study analyzed 4601 patients from a multicenter observational cohort using the Korean Organ Transplantation Registry between 2014 and 2021. After matching the Model for End-stage Liver Disease score and graft-to-recipient body weight ratios because of the extremely different number in each group, the LLG and RLG groups comprised 142 (25.1%) and 423 (74.9%) patients, respectively.

RESULTS

For donors, the median age was higher in the LLG group than in the RLG group (34 y [range, 16-62 y] versus 30 y [16-66 y] ; P  = 0.002). For recipients, the LLG group showed higher 90-d mortality than the RLG group (11 [7.7%] versus 9 [2.1%]; P  = 0.004). The long-term graft survival was significantly worse in the LLG group ( P  = 0.011). In multivariate Cox proportional hazards regression analysis for graft survival, LLG was not a significant risk factor (hazard ratio, 1.01 [0.54-1.87]; P  = 0.980). Otherwise, donor age (≥40 y; 2.18 y [1.35-3.52 y]; P  = 0.001) and recipients' body mass index (<18.5 kg/m 2 ; 2.98 kg/m 2 [1.52-5.84 kg/m 2 ]; P  = 0.002) were independent risk factors for graft survival.

CONCLUSIONS

Although the short-term and long-term graft survival was worse in the LLG group, LLG was not an independent risk factor for graft survival in multivariate analysis. LLGs are still worth considering for selected donors and recipients regarding risk factors for graft survival.

Benefits of liver transplant in critically ill patients with acute-on-chronic liver failure: Implementation of an urgent living-donor program

We evaluated the liver transplantation (LT) criteria in acute-on-chronic liver failure (ACLF), incorporating an urgent living-donor LT (LDLT) program. Critically ill patients with a Chronic Liver Failure Consortium (CLIF-C) ACLF score (CLIF-C_ACLF_score) ≥65, previously considered unsuitable for LT, were included to explore the excess mortality threshold of the CLIF-C_ACLF_score (CLIF-C_ACLF_score_threshold). We followed 854 consecutive patients with ACLF (276 ACLF grade 2 and 215 ACLF grade 3) over 10 years among 4432 LT recipients between 2008 and 2019. For advanced ACLF patients without immediate deceased-donor (DD) allocation, an urgent LDLT program was expedited. The CLIF-C_ACLF_score_threshold was determined by the metrics of transplant survival benefit: >60% 1-year and >50% 5-year survival rate. In predicting post-LT mortality, the CLIF-C_ACLF_score outperformed the (model for end-stage liver disease-sodium) MELD-Na and (model for end-stage liver disease) MELD-3.0 scores but was comparable to the Sundaram ACLF-LT-mortality score. A CLIF-C_ACLF_score ≥65 (n = 54) demonstrated posttransplant survival benefits, with 1-year and 5-year survival rates of 66.7% and 50.4% (P < .001), respectively. Novel CLIF-C_ACLF_score_threshold for 1-year and 5-year mortalities was 70 and 69, respectively. A CLIF-C_ACLF_score-based nomogram for predicting survival probabilities, integrating cardiovascular disease, diabetes, and donor type (LDLT vs DDLT), was generated. This study suggests reconsidering the criteria for unsuitable LT with a CLIF-C_ACLF_score ≥65. Implementing a timely salvage LT strategy, and incorporating urgent LDLT, can enhance survival rates.

Enhanced Artificial Intelligence Methods for Liver Steatosis Assessment Using Machine Learning and Color Image Processing: Liver Color Project

BACKGROUND

The use of livers with significant steatosis is associated with worse transplantation outcomes. Brain death donor liver acceptance is mostly based on subjective surgeon assessment of liver appearance, since steatotic livers acquire a yellowish tone. The aim of this study was to develop a rapid, robust, accurate, and cost-effective method to assess liver steatosis.

METHODS

From June 1, 2018, to November 30, 2023, photographs and tru-cut needle biopsies were taken from adult brain death donor livers at a single university hospital for the study. All the liver photographs were taken by smartphones then color calibrated, segmented, and divided into patches. Color and texture features were then extracted and used as input, and the machine learning method was applied. This is a collaborative project between Vall d'Hebron University Hospital and Barcelona MedTech, Pompeu Fabra University, and is referred to as LiverColor.

RESULTS

A total of 192 livers (362 photographs and 7240 patches) were included. When setting a macrosteatosis threshold of 30%, the best results were obtained using the random forest classifier, achieving an AUROC = 0.74, with 85% accuracy.

CONCLUSION

Machine learning coupled with liver texture and color analysis of photographs taken with smartphones provides excellent accuracy for determining liver steatosis.

The future of liver transplantation

Over the last 50 years, liver transplantation has evolved into a procedure routinely performed in many countries worldwide. Those able to access this therapy frequently experience a miraculous risk-benefit ratio, particularly if they face the imminently life-threatening disease. Over the decades, the success of liver transplantation, with dramatic improvements in early posttransplant survival, has aggressively driven demand. However, despite the emergence of living donors to augment deceased donors as a source of organs, supply has lagged far behind demand. As a result, rationing has been an unfortunate focus in recent decades. Recent shifts in the epidemiology of liver disease combined with transformative innovations in liver preservation suggest that the underlying premise of organ shortage may erode in the foreseeable future. The focus will sharpen on improving equitable access while mitigating constraints related to workforce training, infrastructure for organ recovery and rehabilitation, and their associated costs. Research efforts in liver preservation will undoubtedly blossom with the aim of optimizing both the timing and conditions of transplantation. Coupled with advances in genetic engineering, regenerative biology, and cellular therapies, the portfolio of innovation, both broad and deep, offers the promise that, in the future, liver transplantation will not only be broadly available to those in need but also represent a highly durable life-saving therapy.

A scoping review of nonmedical barriers to living donor liver transplant

This study aims to identify and categorize nonmedical barriers encountered by recipients, donors, and health care providers in the context of living donor liver transplantation (LDLT). Liver transplantation is vital for individuals with liver failure, yet high mortality rates on the transplant waitlist persist. LDLT was introduced to address deceased donor organ shortages; however, its adoption varies widely across regions, prompting the need to explore barriers hindering its implementation. The scoping review employed inclusion and exclusion criteria to identify studies focusing on nonmedical barriers to LDLT in both adult and pediatric populations. Qualitative, quantitative, and mixed-method studies were considered, covering the period from January 2005 to February 2023. The review's search strategy was conducted in the Ovid MEDLINE and Ovid EMBASE databases. Studies meeting the criteria were assessed for their characteristics and findings, which were synthesized into recipient, donor, and provider-level barriers. Among 2394 initially screened articles, 17 studies were eligible for inclusion. Recipient-level barriers encompassed systemic disparities in access, limited social support, immigration status, and inadequate awareness of LDLT. Donor-level barriers involved surgery-related risks, recovery time concerns, financial burdens, and religious beliefs. Provider-level barriers highlighted institutional support inadequacies and specialized surgeon shortages. The scoping review underscores nonmedical barriers to LDLT across recipient, donor, and provider levels. These barriers include socioeconomic disparities, information gaps, and inadequate institutional support. The findings underscore the need for comprehensive national efforts to raise awareness about LDLT and provide essential financial support.

Development and validation of MRI-PDFF cutoffs for living liver donor eligibility assessment

Hepatic steatosis (HS) criteria for living donor liver transplantation (LDLT) donor eligibility should be based on large droplet fat as per Banff consensus recommendations. We aimed to establish magnetic resonance imaging proton density fat fraction cutoffs for HS assessment in potential LDLT donors. This retrospective study included consecutive potential LDLT donors who underwent MRI and liver biopsy between 2013 and 2023 at 2 tertiary institutions, each as development (n = 3062; 2015 men; median [IQR] age of 32 [25-38] y) and external validation (n = 472; 287 men; 35 [26-44] y) data sets. Proton density fat fraction (PDFF) was measured using dedicated MRI sequences. Histologic HS, defined as a large droplet fat fraction, was used as the reference standard. Dual PDFF cutoffs aimed at 95% sensitivity or 95% specificity, for diagnosing histologic HS of ≥10%, ≥20%, ≥30%, and ≥40%, were determined in the development data set using 10-fold cross-validation. The cutoffs were then validated in the external validation data set. The equation for estimating histologic HS from PDFF was also derived using linear regression. The PDFF cutoffs for histologic HS of ≥10%, ≥20%, ≥30%, and ≥40%, targeting 95% sensitivity, were 3.7%, 5.5%, 8.0%, and 10.0%, respectively. External validation demonstrated high sensitivities ≥97.9% with specificities ranging from 60.9% to 95.1%. The PDFF cutoffs targeting 95% specificity were 6.3%, 8.0%, 9.1%, and 10.1%, respectively. External validation rendered high specificities ranging from 88.5% to 95.3%, with sensitivities ranging from 76.6% to 100%. For diagnosing histologic HS ≥30%, which is the most prevalently used threshold for LDLT donor eligibility assessment, the PDFF cutoffs achieved sensitivities and specificities of over 90%. The equation of (Histologic HS = -2.95 + 1.93 × PDFF) was derived.

Biliary complications after adult-to-adult living-donor liver transplantation: An international multicenter study of 3633 cases

In living-donor liver transplantation, biliary complications including bile leaks and biliary anastomotic strictures remain significant challenges, with incidences varying across different centers. This multicentric retrospective study (2016-2020) included 3633 adult patients from 18 centers and aimed to identify risk factors for these biliary complications and their impact on patient survival. Incidences of bile leaks and biliary strictures were 11.4% and 20.6%, respectively. Key risk factors for bile leaks included multiple bile duct anastomoses (odds ratio, [OR] 1.8), Roux-en-Y hepaticojejunostomy (OR, 1.4), and a history of major abdominal surgery (OR, 1.4). For biliary anastomotic strictures, risk factors were ABO incompatibility (OR, 1.4), blood loss >1 L (OR, 1.4), and previous abdominal surgery (OR, 1.7). Patients experiencing biliary complications had extended hospital stays, increased incidence of major complications, and higher comprehensive complication index scores. The impact on graft survival became evident after accounting for immortal time bias using time-dependent covariate survival analysis. Bile leaks and biliary anastomotic strictures were associated with adjusted hazard ratios of 1.7 and 1.8 for graft survival, respectively. The study underscores the importance of minimizing these risks through careful donor selection and preoperative planning, as biliary complications significantly affect graft survival, despite the availability of effective treatments.

The aim of donor safety: surgical approaches and current results

Living liver donation (LLD) has been suggested as a potential solution to reduce the waitlist mortality for liver transplantation (LT) recipients by facilitating living donor liver transplantation (LDLT). Ensuring both donor and recipient safety is a critical aspect of LDLT. An accurate understanding of the complexity and extend of safety outcomes of the donor is imperative to maintain the high-quality standard this medical program requires. This review seeks to outline safety outcome parameters of interest for donors. Early postoperative mortality is very low with no significant differences comparing left lobe to right lobe LLD. Complications most commonly are biliary (leakage or strictures), bleeding, respiratory or pulmonary, gastrointestinal or infectious. Return to full-time work and quality of life are essential parameters in the mid and long term. As evidence continues to accumulate, outcomes may evolve with the expansion of minimal invasive surgery practice and currently laparoscopic approach is recommended in large experienced centers. By offering safer operations that require fewer incisions or liver resections, living liver donations can be further encouraged, and the perception of the procedure can be improved. Rational consideration of the safety of the donor and in-depth discussion and evaluation with the patient is of utmost importance.

Approach to Liver Transplantation: Is There a Difference between East and West?

Liver transplantation (LT) remains the only curative treatment for end-stage liver disease as well as acute liver failure. With the exponential increase in organ demand due to the increasing incidence and prevalence of liver diseases, the need to overcome the supply and demand mismatch has arisen. In this review, we discuss the current universal status of LT, emphasizing various LT practices worldwide.

Transplant oncology - Current indications and strategies to advance the field

Liver transplantation (LT) was originally described by Starzl as a promising strategy to treat primary malignancies of the liver. Confronted with high recurrence rates, indications drifted towards non-oncologic liver diseases with LT finally evolving from a high-risk surgery to an almost routine surgical procedure. Continuously improving outcomes following LT and evolving oncological treatment strategies have driven renewed interest in transplant oncology. This is not only reflected by constant refinements to the criteria for LT in patients with HCC, but especially by efforts to expand indications to other primary and secondary liver malignancies. With new patient-centred oncological treatments on the rise and new technologies to expand the donor pool, the field has the chance to come full circle. In this review, we focus on the concept of transplant oncology, current indications, as well as technical and ethical aspects in the context of donor organs as precious resources.

Increasing practice and acceptable outcomes of high-MELD living donor liver transplantation in the USA

Recent deceased-donor allocation changes in the United States may have increased high-Model for End-Stage Liver Disease (MELD) living donor liver transplantation (LDLT); however, outcomes in these patients remain poorly defined. We aimed to examine the impact of the MELD score on LDLT outcomes. Using UNOS data (January 1, 2010-December 31, 2021), LDLT recipients were identified and stratified into low-MELD (<15), intermediate-MELD (15-24), and high-MELD (≥25) groups. We compared outcomes between MELD-stratified LDLT groups and between MELD-stratified LDLT and donation after brain death liver transplantation recipients. We used Kaplan-Meier analysis to compare graft survival rates and multivariable Cox proportional hazards modeling to identify factors associated with graft outcomes. Of 3558 LDLTs, 1605 (45.1%) were low-MELD, 1616 (45.4%) intermediate-MELD, and 337 (9.5%) high-MELD. Over the study period, the annual number of LDLTs increased from 282 to 569, and the proportion of high-MELD LDLTs increased from 3.9% to 7.7%. Graft survival was significantly higher in low-MELD versus high-MELD LDLT recipients (adjusted HR = 1.36, 95% CI: 1.03-1.79); however, 5-year survival exceeded 70.0% in both groups. We observed no significant difference in graft survival between high-MELD LDLT and high-MELD donation after brain death liver transplantation recipients (adjusted HR: 1.25, 95% CI:0.99-1.58), with a 5-year survival of 71.5% and 77.3%, respectively. Low LDLT center volume (<3 LDLTs/year) and recipient life support requirement were both associated with inferior graft outcomes among high-MELD LDLT recipients. While higher MELD scores confer graft failure risk in LDLT, high-MELD LDLT outcomes are acceptable with similar outcomes to MELD-stratified donation after brain death liver transplantation recipients. Future practice guidance should consider the expansion of LDLT recommendations to high-MELD recipients in centers with expertise to help reduce donor shortage.

Novel Benchmark for Adult-to-Adult Living-donor Liver Transplantation: Integrating Eastern and Western Experiences

OBJECTIVE

To define benchmark values for adult-to-adult living-donor liver transplantation (LDLT).

BACKGROUND

LDLT utilizes living-donor hemiliver grafts to expand the donor pool and reduce waitlist mortality. Although references have been established for donor hepatectomy, no such information exists for recipients to enable conclusive quality and comparative assessments.

METHODS

Patients undergoing LDLT were analyzed in 15 high-volume centers (≥10 cases/year) from 3 continents over 5 years (2016-2020), with a minimum follow-up of 1 year. Benchmark criteria included a Model for End-stage Liver Disease ≤20, no portal vein thrombosis, no previous major abdominal surgery, no renal replacement therapy, no acute liver failure, and no intensive care unit admission. Benchmark cutoffs were derived from the 75th percentile of all centers' medians.

RESULTS

Of 3636 patients, 1864 (51%) qualified as benchmark cases. Benchmark cutoffs, including posttransplant dialysis (≤4%), primary nonfunction (≤0.9%), nonanastomotic strictures (≤0.2%), graft loss (≤7.7%), and redo-liver transplantation (LT) (≤3.6%), at 1-year were below the deceased donor LT benchmarks. Bile leak (≤12.4%), hepatic artery thrombosis (≤5.1%), and Comprehensive Complication Index (CCI ® ) (≤56) were above the deceased donor LT benchmarks, whereas mortality (≤9.1%) was comparable. The right hemiliver graft, compared with the left, was associated with a lower CCI ® score (34 vs 21, P < 0.001). Preservation of the middle hepatic vein with the right hemiliver graft had no impact neither on the recipient nor on the donor outcome. Asian centers outperformed other centers with CCI ® score (21 vs 47, P < 0.001), graft loss (3.0% vs 6.5%, P = 0.002), and redo-LT rates (1.0% vs 2.5%, P = 0.029). In contrast, non-benchmark low-volume centers displayed inferior outcomes, such as bile leak (15.2%), hepatic artery thrombosis (15.2%), or redo-LT (6.5%).

CONCLUSIONS

Benchmark LDLT offers a valuable alternative to reduce waitlist mortality. Exchange of expertise, public awareness, and centralization policy are, however, mandatory to achieve benchmark outcomes worldwide.

Living donor liver transplantation can address disparities in transplant access for patients with primary sclerosing cholangitis

BACKGROUND

Liver transplantation (LT) is frequently lifesaving for people living with primary sclerosing cholangitis (PSC). However, patients are waitlisted for LT according to the model for end-stage liver disease-sodium (MELD-Na) score, which may not accurately reflect the burden of living with PSC. We sought to describe and analyze the clinical trajectory for patients with PSC referred for LT, in a mixed deceased donor/living donor transplant program.

METHODS

This was a retrospective cohort study from November 2012 to December 2019, including all patients with PSC referred for assessment at the University Health Network Liver Transplant Clinic. Patients who required multiorgan transplant or retransplantation were excluded. Liver symptoms, hepatobiliary malignancy, MELD-Na progression, and death were abstracted from chart review. Competing risk analysis was used for timing of LT, transplant type, and death.

RESULTS

Of 172 PSC patients assessed, 84% (n = 144) were listed of whom 74% were transplanted. Mean age was 47.6 years, and 66% were male. Overall mortality was 18.2% at 2 years. During the follow-up, 16% (n = 23) were removed from the waitlist for infection, clinical deterioration, liver-related mortality or new cancer; 3 had clinical improvement. At listing, 82% (n = 118) had a potential living donor (pLD). Patients with pLD had significantly lower waitlist and liver-related waitlist mortality (HR 0.20, p<0.001 and HR 0.17, p<0.001, respectively), and higher rates of transplantation (HR 1.83, p = 0.05). Exception points were granted to 13/172 (7.5%) patients.

CONCLUSIONS

In a high-volume North American LT center, most patients with PSC assessed for transplant were listed and subsequently transplanted. However, this was a consequence of patients engaging in living donor transplantation. Our findings support the concern from patients with PSC that MELD-Na allocation does not adequately address their needs.

Breakthroughs in Hepatocellular Carcinoma Therapies

Several breakthroughs in hepatocellular carcinoma (HCC) therapy across tumor stages provide hope to improve its dismal prognosis. Although surgical and local ablative therapies have few significant changes in technique, an improved understanding of tumor biology has facilitated increase numbers of patients who are now eligible to undergo curative-intent procedures. Most notably, acceptable post-transplant outcomes can be achieved in well selected patients whose tumors are downstaged into Milan Criteria. Adjuvant therapy in patients at high risk of recurrence also significantly improves recurrence-free survival after resection or ablation. For patients with liver-localized disease who are not eligible for curative-intent procedures, transarterial chemoembolization (TACE) was historically the treatment modality of choice, regardless of tumor burden; however, there is now increased recognition of patients who are "TACE unsuitable" and may be better treated with systemic therapy. The greatest evolution in HCC treatment options has occurred with systemic therapy, where several new agents are now available in the first- and second-line setting, including immune checkpoint inhibitor combinations. Objective responses are observed in approximately 30% of patients and median survival is approaching 2 years. The availability of immune checkpoint inhibitors has renewed interest in combination therapies for earlier tumor stages, with several phase III trials ongoing. Considering increasing complexities of HCC care, requiring decisions between therapies delivered by different providers, multidisciplinary care is critical and is associated with improved clinical outcomes. In this review, we detail major breakthroughs in HCC therapy, how these breakthroughs can be applied in clinical practice, and remaining areas in need of further research.

Machine learning-based mortality prediction models using national liver transplantation registries are feasible but have limited utility across countries

Many countries curate national registries of liver transplant (LT) data. These registries are often used to generate predictive models; however, potential performance and transferability of these models remain unclear. We used data from 3 national registries and developed machine learning algorithm (MLA)-based models to predict 90-day post-LT mortality within and across countries. Predictive performance and external validity of each model were assessed. Prospectively collected data of adult patients (aged ≥18 years) who underwent primary LTs between January 2008 and December 2018 from the Canadian Organ Replacement Registry (Canada), National Health Service Blood and Transplantation (United Kingdom), and United Network for Organ Sharing (United States) were used to develop MLA models to predict 90-day post-LT mortality. Models were developed using each registry individually (based on variables inherent to the individual databases) and using all 3 registries combined (variables in common between the registries [harmonized]). The model performance was evaluated using area under the receiver operating characteristic (AUROC) curve. The number of patients included was as follows: Canada, n = 1214; the United Kingdom, n = 5287; and the United States, n = 59,558. The best performing MLA-based model was ridge regression across both individual registries and harmonized data sets. Model performance diminished from individualized to the harmonized registries, especially in Canada (individualized ridge: AUROC, 0.74; range, 0.73-0.74; harmonized: AUROC, 0.68; range, 0.50-0.73) and US (individualized ridge: AUROC, 0.71; range, 0.70-0.71; harmonized: AUROC, 0.66; range, 0.66-0.66) data sets. External model performance across countries was poor overall. MLA-based models yield a fair discriminatory potential when used within individual databases. However, the external validity of these models is poor when applied across countries. Standardization of registry-based variables could facilitate the added value of MLA-based models in informing decision making in future LTs.