D-MELD, a simple predictor of post liver transplant mortality for optimization of donor/recipient matching

The Future Frontier of Liver Transplantation Exploring Young Donor Allocation Strategies for HCC Recipients

Background

The role of donor age in liver transplantation (LT) outcomes for hepatocellular carcinoma (HCC) is controversial. Given the significant risk of HCC recurrence post-LT, optimizing donor/recipient matching is crucial. This study reassesses the impact of young donors on LT outcomes in patients with HCC.

Methods

A retrospective review of 11 704 LT cases from the United Network for Organ Sharing database (2012-2021) was conducted. The study focused on the effect of donor age on recurrence-free survival, using hazard associated with LT for HCC (HALT-HCC) and Metroticket 2.0 scores to evaluate post-LT survival in patients with HCC.

Results

Of 4706 cases with young donors, 11.0% had HCC recurrence or death within 2 y, and 18.3% within 5 y. These outcomes were comparable with those of non-young donors. A significant correlation between donor age and post-LT recurrence or mortality (P = 0.04) was observed, which became statistically insignificant after tumor-related adjustments (P = 0.32). The Kaplan-Meier curve showed that recipients with lower HALT-HCC scores (<9) and Metroticket 2.0 scores (<2.2) significantly benefited from young donors, unlike those exceeding these score thresholds. Cox regression analysis showed that donor age significantly influenced outcomes in recipients below certain score thresholds but was less impactful for higher scores.

Conclusions

Young donors are particularly beneficial for LT recipients with less aggressive HCC, as indicated by their HALT-HCC and Metroticket 2.0 scores. These findings suggest strategically allocating young donors to recipients with less aggressive tumor profiles, which could foster more efficient use of the scarce donor supply and potentially enhance post-LT outcomes.

Preoperative DLCO predicts severe early complications after liver transplantation

BACKGROUND

Severe early complications are common after liver transplantation (LT) and are a key determinant of LT-related morbidity and mortality. The aim of this study was to assess whether lung function measured in the pre-operative period predicted complicated outcomes in the first month after LT.

MATERIAL AND METHODS

Patients with mild-to-moderate liver disease (Model for End stage Liver Disease-MELD score≤30) who underwent LT between October 2015 and May 2020 in a single centre were retrospectively included. The primary endpoint was the occurrence of severe early complications after LT defined by mechanical ventilation duration > 2 days or length of ICU stay > 7 days or reintubation or death < 1 month after LT.

RESULTS

One hundred and twenty patients were included (age 59 [53-64] years, 72 % men). Forty patients (33 %) had early complications after LT. Measured and%predicted hemoglobin-corrected lung transfer capacity for carbon monoxide (DLCOc) were significantly lower in patients with severe early complications after LT. DLCOc was the only variable that associated independently with severe early complications by multivariate analysis. DLCOc under 16.3 ml.min-1.mmHg-1 predicted respiratory complications with a sensitivity of 67.5 % and a specificity of 62.9 %. DLCOc%pred under 61.5 % had a sensitivity of 56.8 % and a specificity of 72 %. DLCOc independently associated with forced vital capacity (FVC), pulmonary emphysema, and the muscle mass index.

CONCLUSION

A decrease in DLCOc indicated an increased risk of severe early complications after LT.

LIVER RETRANSPLANTATION: PROGNOSTIC SCORES AND RESULTS IN THE STATE OF PARANÁ

BACKGROUND

Hepatic retransplantation is associated with higher morbidity and mortality when compared to primary transplantation. Given the scarcity of organs and the need for efficient allocation, evaluating parameters that can predict post-retransplant survival is crucial.

AIMS

This study aimed to analyze prognostic scores and outcomes of hepatic retransplantation.

METHODS

Data on primary transplants and retransplants carried out in the state of Paraná in 2019 and 2020 were analyzed. The two groups were compared based on 30-day survival and the main prognostic scores of the donor and recipient, namely Model for End-Stage Liver Disease (MELD), MELD-albumin (MELD-a), Donor MELD (D-MELD), Survival Outcomes Following Liver Transplantation (SOFT), Preallocation Score to Predict Survival Outcomes Following Liver Transplantation (P-SOFT), and Balance of Risk (BAR).

RESULTS

A total of 425 primary transplants and 30 retransplants were included in the study. The main etiology of hepatopathy in primary transplantation was ethylism (n=140; 31.0%), and the main reasons for retransplantation were primary graft dysfunction (n=10; 33.3%) and hepatic artery thrombosis (n=8; 26.2%). The 30-day survival rate was higher in primary transplants than in retransplants (80.5% vs. 36.7%, p=0.001). Prognostic scores were higher in retransplants than in primary transplants: MELD 30.6 vs. 20.7 (p=0.001); MELD-a 31.5 vs. 23.5 (p=0.001); D-MELD 1234.4 vs. 834.0 (p=0.034); SOFT 22.3 vs. 8.2 (p=0.001); P-SOFT 22.2 vs. 7.8 (p=0.001); and BAR 15.6 vs. 8.3 (p=0.001). No difference was found in terms of Donor Risk Index (DRI).

CONCLUSIONS

Retransplants exhibited lower survival rates at 30 days, as predicted by prognostic scores, but unrelated to the donor's condition.

A novel scoring system to predict short-term mortality after living donor liver transplantation for acute liver failure

Liver transplantation is often the only lifesaving option for acute liver failure (ALF); however, the predictors of short-term mortality (death within one year) after living donor liver transplantation (LDLT) for ALF have yet to be defined. We retrospectively collected patients ≥18 years old who underwent LDLT for ALF between 2010 and 2020 at 35 centers in Asia. Univariate and multivariate logistic regression analyses were conducted to identify the clinical variables related to short-term mortality and establish a novel scoring system. The Kaplan-Meier method was performed to explore the association between the score and overall survival. Of the 339 recipients, 46 (13.6%) died within 1 year after LDLT. Multivariate analyses revealed 4 independent risk factors for death: use of vasopressors or mechanical ventilation, the higher model for end-stage liver disease score, and a lower graft-to-recipient weight ratio. The internally validated c-statistic of the short-term mortality after transplant (SMT) score derived from these 4 variables was 0.80 (95% confidence interval: 0.74-0.87). The SMT score successfully stratified recipients into low-, intermediate-, and high-risk groups with 1-year overall survival rates of 96%, 80%, and 50%, respectively. In conclusion, our novel SMT score based on 4 predictors will guide ALF recipient and living donor selection.

Current Understanding of Marginal Grafts in Liver Transplantation

End-stage liver disease (ESLD), stemming from a spectrum of chronic liver pathologies including chronic liver failure, acute cirrhosis decompensation and hepatocellular carcinoma, imposes a significant global healthcare burden. Liver transplantation (LT) remains the only treatment for ESLD. However, the escalating mortality on transplant waitlists has prompted the utilization of marginal liver grafts in LT procedures. These grafts primarily encompass elderly livers, steatotic livers, livers from donation after circulatory death, split livers and those infected with the hepatitis virus. While the expansion of the donor pool offers promise, it also introduces concomitant risks. These encompass graft failure, biliary and cardiovascular complications, the recurrence of liver disease and reduced patient and graft survival. Consequently, various established strategies, ranging from improved donor-recipient matching to surgical interventions, have emerged to mitigate these risks. This article undertakes a comprehensive assessment of the current landscape, evaluating the viability of diverse marginal liver grafts. Additionally, it synthesizes approaches aimed at enhancing the quality of such marginal liver grafts. The overarching objective is to augment the donor pool and ameliorate the risk factors associated with the shortage of liver grafts.

The role of donor sex on the post-liver transplant outcomes in patients with primary sclerosing cholangitis

BACKGROUND AND AIMS

Primary sclerosing cholangitis (PSC) can result in hepatic decompensation and require liver transplantation (LT). This study investigates the effect of the sex of the donor and recipient as a prognostic risk factor for adverse outcomes after LT in patients with PSC.

METHODS

UNOS registry was used to select LT patients with PSC from 1987 to 2019. The study cohort was stratified based on the sex of the recipient and further subdivided based on the sex of the donor. The primary endpoints of this study were all-cause mortality and graft failure, which were evaluated using a sequential Cox regression analysis.

RESULTS

This study included 2829 patients; 906 female recipients were transplanted from 441 male donors and 465 female donors. 1923 male recipients were transplanted from 1194 male donors and 729 female donors. Within the mismatch analyses, the male-to-male recipients also had a significantly reduced hazard ratio of graft failure compared to female-to-male transplants [aHR 0.51, 95% confidence interval (CI) 0.33-0.79, P  = 0.003]. No difference in graft failure was observed in the mismatched female recipient subgroup. The mismatched male recipient group also showed a decreased hazard ratio of mortality from graft rejection and respiratory causes. No differences in specific mortality causes were identified in the mismatched female recipient group.

CONCLUSION

This study demonstrated an increase in the risk of graft failure and mortality secondary to graft failure in male recipients of female donor livers. No differences in mortality or graft failure were identified in female recipients of male livers.

Changes of long-term survival of resection and liver transplantation in hepatocellular carcinoma throughout the years: A meta-analysis

BACKGROUND

Hepatocellular Carcinoma (HCC) still is one of the most detrimental malignant diseases in the world. As two curative surgical therapies exist, the discussion whether to opt for liver resection (LR) or transplantation (LT) is ongoing, especially as novel techniques to improve outcome have emerged for both. The aim of the study was to investigate how the utilization and outcome of the respective modalities changed through time.

METHODS

We searched Medline and PubMed for relevant publications comparing LT and LR in HCC patients during the time period from 1990 to 2022, prior to March 31, 2023. A total of 63 studies involving 19,804 patients - of whom 8178 patients received a liver graft and 11,626 underwent partial hepatectomy - were included in this meta-analysis.

RESULTS

LT is associated with significantly better 5-year overall survival (OS) (64.83%) and recurrence-free survival (RFS) (70.20%) than LR (OS: 50.83%, OR: 1.79, p < 0.001; RFS: 34.46%, OR: 5.32, p < 0.001). However, these differences are not as evident in short-term intervals. Older cohorts showed comparable disparities between the outcome of the respective modalities, as did newer cohorts after 2005. This might be due to the similar improvement in survival rates that were observed for both, LT (15-23%) and LR (12-20%) during the last 30 years.

CONCLUSION

LT still outperforms LR in the therapy of HCC in terms of long-term survival rates. Yet, LR outcome has remarkably improved which is of major importance in reference to the well-known limitations that occur in LT.

Establishing a HOPE Program in a Real-life Setting: A Brazilian Case Series

Background

Although hypothermic oxygenated perfusion (HOPE) improves posttransplant outcomes, setting up machine perfusion programs may be subjected to specific obstacles under different conditions. This study aims to describe the establishment of HOPE in a real-life setting in Brazil.

Methods

Extended criteria donors in donation after brain death organs preserved by HOPE were accepted for higher-risk candidates needing expedited transplantation, perceived as those who would benefit most from the technique because of its limited availability. Extended criteria donors was defined by the Eurotransplant criteria. High-risk transplant candidates were characterized by suboptimal surgical conditions related to the recipient or the procedure.

Results

Six HOPE-preserved grafts were transplanted from February 2022 to August 2022. The mean donor risk index was 1.7 (SD 0.5). One organ was severely steatotic, and 3 had an anticipated cold ischemia time above 12 h. Recipients' mean model for end-stage liver disease was 28.67 (SD 6.79), with 1 case of retransplant, 1 of refractory ascites, and 1 of acute-on-chronic liver failure. The mean cold ischemia time was 5 h 42 min (SD 82 min), HOPE 6 h 3 min (SD 150 min), and total preservation time 11 h 46 min (SD 184 min). No case had early allograft dysfunction. The mean length of hospital stay was 10 d with 100% graft and patient survival and no ischemic cholangiopathies at a median follow-up of 15 mo (min 12, max 18). Costs and country-specific legal regulations for device utilization were the major hurdles to implementing the program.

Conclusion

We presented a pathway to introduce and rationalize the use of HOPE in a scenario of challenging donor-recipient matching with good results. These findings may aid in implementing machine perfusion programs, especially in settings with limited resources or complex transplant logistics.

The novel SALT-M score predicts 1-year post-transplant mortality in patients with severe acute-on-chronic liver failure

BACKGROUND & AIMS

Twenty-eight-day mortality ranges from 30-90% in patients with acute-on-chronic liver failure grades 2/3 (severe ACLF). Though liver transplantation (LT) has demonstrated a survival benefit, the scarcity of donor organs and uncertainty regarding post-LT mortality among patients with severe ACLF may cause hesitancy. We developed and externally validated a model to predict 1-year post-LT mortality in severe ACLF, called the Sundaram ACLF-LT-Mortality (SALT-M) score, and estimated the median length of stay (LoS) after LT (ACLF-LT-LoS).

METHODS

In 15 LT centers in the US, we retrospectively identified a cohort of patients with severe ACLF transplanted between 2014-2019, followed up to Jan'2022. Candidate predictors included demographics, clinical and laboratory values, and organ failures. We selected predictors in the final model using clinical criteria and externally validated them in two French cohorts. We provided measures of overall performance, discrimination, and calibration. We used multivariable median regression to estimate LoS after adjusting for clinically relevant factors.

RESULTS

We included 735 patients, of whom 521 (70.8%) had severe ACLF (120 ACLF-3, external cohort). The median age was 55 years, and 104 with severe ACLF (19.9%) died within 1-year post-LT. Our final model included age >50 years, use of 1/≥2 inotropes, presence of respiratory failure, diabetes mellitus, and BMI (continuous). The c-statistic was 0.72 (derivation) and 0.80 (validation), indicating adequate discrimination and calibration based on the observed/expected probability plots. Age, respiratory failure, BMI, and presence of infection independently predicted median LoS.

CONCLUSIONS

The SALT-M score predicts mortality within 1-year after LT in patients with ACLF. The ACLF-LT-LoS score predicted median post-LT stay. Future studies using these scores could assist in determining transplant benefits.

IMPACT AND IMPLICATIONS

Liver transplantation (LT) may be the only life-saving procedure available to patients with acute-on-chronic liver failure (ACLF), but clinically instability can augment the perceived risk of post-transplant mortality at 1 year. We developed a parsimonious score with clinically and readily available parameters to objectively assess 1-year post-LT survival and predict median length of stay after LT. We developed and externally validated a clinical model called the Sundaram ACLF-LT-Mortality score in 521 US patients with ACLF with 2 or ≥3 organ failure(s) and 120 French patients with ACLF grade 3. The c-statistic was 0.72 in the development cohort and 0.80 in the validation cohort. We also provided an estimation of the median length of stay after LT in these patients. Our models can be used in discussions on the risks/benefits of LT in patients listed with severe ACLF. Nevertheless, the score is far from perfect and other factors, such as patient's preference and center-specific factors, need to be considered when using these tools.

Evaluating the outcomes of donor-recipient age differences in young adults undergoing liver transplantation

The current liver allocation system may be disadvantaging younger adult recipients as it does not incorporate the donor-recipient age difference. Given the longer life expectancy of younger recipients, the influences of older donor grafts on their long-term prognosis should be elucidated. This study sought to reveal the long-term prognostic influence of the donor-recipient age difference in young adult recipients. Adult patients who received initial liver transplants from deceased donors between 2002 and 2021 were identified from the UNOS database. Young recipients (patients 45 years old or below) were categorized into 4 groups: donor age younger than the recipient, 0-9 years older, 10-19 years older, or 20 years older or above. Older recipients were defined as patients 65 years old or above. To examine the influence of the age difference in long-term survivors, conditional graft survival analysis was conducted on both younger and older recipients. Among 91,952 transplant recipients, 15,170 patients were 45 years old or below (16.5%); these were categorized into 6,114 (40.3%), 3,315 (21.9%), 2,970 (19.6%), and 2,771 (18.3%) for groups 1-4, respectively. Group 1 demonstrated the highest probability of survival, followed by groups 2, 3, and 4 for the actual graft survival and conditional graft survival analyses. In younger recipients who survived at least 5 years post-transplant, inferior long-term survival was observed when there was an age difference of 10 years or above (86.9% vs. 80.6%, log-rank p <0.01), whereas there was no difference in older recipients (72.6% vs. 74.2%, log-rank p =0.89). In younger patients who are not in emergent need of a transplant, preferential allocation of younger aged donor offers would optimize organ utility by increasing postoperative graft survival time.

The evolution of the liver transplant candidate

The first successful human liver transplant (LT) was done over 60 years ago; since the early pioneering days, this procedure has become a routine treatment with excellent outcomes for the great majority of recipients. Over the last six decades, indications have evolved. Use of LT for hepatic malignancy is becoming less common as factors that define a successful outcome are being increasingly defined, and alternative therapeutic options become available. Both Hepatitis B and C virus associated liver disease are becoming less common indications as medical treatments become more effective in preventing end-stage disease. Currently, the most common indications are alcohol-related liver disease and metabolic associated liver disease. The developing (and controversial) indications include acute on chronic liver failure, alcoholic hepatitis and some rarer malignancies such as non-resectable colorectal cancer liver metastases, neuroendocrine tumours and cholangiocarcinoma. Candidates are becoming older and with greater comorbidities, A relative shortage of donor organs remains the greatest cause for reducing access to LT; therefore, various countries have developed transparent approaches to allocation of this life saving and life enhancing resource. Reliance on prognostic models has gone some way to improve transparency and increase equity of access but these approaches have their limitations.

Maximizing utility of nondirected living liver donor grafts using machine learning

Objective

There is an unmet need for optimizing hepatic allograft allocation from nondirected living liver donors (ND-LLD).

Materials and method

Using OPTN living donor liver transplant (LDLT) data (1/1/2000-12/31/2019), we identified 6328 LDLTs (4621 right, 644 left, 1063 left-lateral grafts). Random forest survival models were constructed to predict 10-year graft survival for each of the 3 graft types.

Results

Donor-to-recipient body surface area ratio was an important predictor in all 3 models. Other predictors in all 3 models were: malignant diagnosis, medical location at LDLT (inpatient/ICU), and moderate ascites. Biliary atresia was important in left and left-lateral graft models. Re-transplant was important in right graft models. C-index for 10-year graft survival predictions for the 3 models were: 0.70 (left-lateral); 0.63 (left); 0.61 (right). Similar C-indices were found for 1-, 3-, and 5-year graft survivals. Comparison of model predictions to actual 10-year graft survivals demonstrated that the predicted upper quartile survival group in each model had significantly better actual 10-year graft survival compared to the lower quartiles (p<0.005).

Conclusion

When applied in clinical context, our models assist with the identification and stratification of potential recipients for hepatic grafts from ND-LLD based on predicted graft survivals, while accounting for complex donor-recipient interactions. These analyses highlight the unmet need for granular data collection and machine learning modeling to identify potential recipients who have the best predicted transplant outcomes with ND-LLD grafts.

Delta Neutrophil Index as a New Early Mortality Predictor after Liver Transplantation

Background: Patients with liver disease display numerous defects of the immune system, so infection is a frequent complication of both acute and chronic liver disease. These infections are independently associated with poor outcomes after liver transplantation. Our objective was to evaluate the delta neutrophil index (DNI), a new inflammation marker, as a predictor of survival after liver transplantation (LT). Methods: This observational study retrospectively evaluated the records of 712 patients who underwent LT from January 2010 to February 2018. DNI was evaluated at pre-transplantation and 1, 7, 14, and 30 days after operation. Statistical analysis was performed using the T-test or chi-square test, and logistic regression analysis. Results: The mean MELD score was 16.7 ± 9.4 (0–48). There were 125 mortality cases (17.8%) after liver transplantation. Mean DNI was 1.61 at pre-transplantation, 3.94 one day after operation, 2.67 seven days after operation, 1.61 fourteen days after operation, and 1.64 thirty days after operation, respectively. In multivariate analysis, DNI seven and fourteen days after operation was revealed as an independent prognostic factor for mortality after liver transplantation (p = 0.040 and p < 0.0001). Conclusions: The DNI is a simple and reliable predictor of patient mortality after liver transplantation.

How Can Machine Perfusion Change the Paradigm of Liver Transplantation for Patients with Perihilar Cholangiocarcinoma?

Perihilar cholangiocarcinomas (pCCA) are rare yet aggressive tumors originating from the bile ducts. While surgery remains the mainstay of treatment, only a minority of patients are amenable to curative resection, and the prognosis of unresectable patients is dismal. The introduction of liver transplantation (LT) after neoadjuvant chemoradiation for unresectable pCCA in 1993 represented a major breakthrough, and it has been associated with 5-year survival rates consistently >50%. Despite these encouraging results, pCCA has remained a niche indication for LT, which is most likely due to the need for stringent candidate selection and the challenges in preoperative and surgical management. Machine perfusion (MP) has recently been reintroduced as an alternative to static cold storage to improve liver preservation from extended criteria donors. Aside from being associated with superior graft preservation, MP technology allows for the safe extension of preservation time and the testing of liver viability prior to implantation, which are characteristics that may be especially useful in the setting of LT for pCCA. This review summarizes current surgical strategies for pCCA treatment, with a focus on unmet needs that have contributed to the limited spread of LT for pCCA and how MP could be used in this setting, with a particular emphasis on the possibility of expanding the donor pool and improving transplant logistics.

Pre-transplant Biomarkers of Immune Dysfunction Improve Risk Assessment of Post-transplant Mortality Compared to Conventional Clinical Risk Scores

Introduction

There is a critical need to accurately stratify liver transplant (LT) candidates' risk of post-LT mortality prior to LT to optimize patient selection and avoid futility. Here, we compare previously described pre-LT clinical risk scores with the recently developed Liver Immune Frailty Index (LIFI) for prediction of post-LT mortality. LIFI measures immune dysregulation based on pre-LT plasma HCV IgG, MMP3 and Fractalkine. LIFI accurately predicts post-LT mortality, with LIFI-low corresponding to 1.4% 1-year post-LT mortality compared with 58.3% for LIFI-high (C-statistic=0.85).

Methods

LIFI was compared to MELD, MELD-Na, MELD 3.0, D-MELD, MELD-GRAIL, MELD-GRAIL-Na, UCLA-FRS, BAR, SOFT, P-SOFT, and LDRI scores on 289 LT recipients based on waitlist data at the time of LT. Survival, hazard of early post-LT death, and discrimination power (C-statistic) were assessed.

Results

LIFI showed superior discrimination (highest C-statistic) for post-LT mortality when compared to all other risk scores, irrespective of biologic MELD. On univariate analysis, the LIFI showed a significant correlation with mortality 6-months, as well as 1-, 3-, and 5-years. No other pre-LT scoring system significantly correlated with post-LT mortality. On bivariate adjusted analysis, African American race (p<0.05) and pre-LT cardiovascular disease (p=0.053) were associated with early- and long-term post-LT mortality. Patients who died within 1-yr following LT had a significantly higher incidence of infections, including 30-day and 90-day incidence of any infection, pneumonia, abdominal infections, and UTI (p<0.05).

Conclusions

LIFI, which measures pre-LT biomarkers of immune dysfunction, more accurately predicts risk of post-LT futility compared with current clinical predictive models. Pre-LT assessment of immune dysregulation may be critical in predicting mortality after LT and may optimize selection of candidates with lowest risk of futile outcomes.

Validation of risk scores for allograft failure after liver transplantation in Germany: a retrospective cohort analysis

A growing number of clinical risk scores have been proposed to predict allograft failure after liver transplantation. However, validation of currently available scores in the Eurotransplant region is still lacking. We aimed to analyze all clinically relevant donor and recipient risk scores on a large German liver transplantation data set and performed a retrospective cohort analysis of liver transplantations performed at the Charité-Universitätsmedizin Berlin from January 2007 until December 2021 with organs from donation after brain death. We analyzed 9 previously published scores in 906 liver transplantations [Eurotransplant donor risk index (ET-DRI/DRI), donor age and model for end-stage liver disease (D-MELD), balance of risk (BAR), early allograft dysfunction (EAD), model for early allograft function (MEAF), liver graft assessment following transplantation (L-GrAFT7), early allograft failure simplified estimation (EASE), and a score by Rhu and colleagues). The EASE score had the best predictive value for 3-month, 6-month, and 12-month graft survival with a c-statistic of 0.8, 0.77, and 0.78, respectively. In subgroup analyses, the EASE score was suited best for male recipients with a high-MELD (>25) and an EAD organ. Scores only based on pretransplant data performed worse compared to scores including postoperative data (eg, ET-DRI vs. EAD, p<0.001 at 3-month graft survival). Out of these, the BAR score performed best with a c-statistic of 0.6. This a comprehensive comparison of the clinical utility of risk scores after liver transplantation. The EASE score sufficiently predicted 12-month graft and patient survival. Despite a relatively complex calculation, the EASE score provides significant prognostic value for patients and health care professionals in the Eurotransplant region.

Liver transplantation for NAFLD cirrhosis: Age and recent coronary angioplasty are major determinants of survival

BACKGROUND AND AIMS

Liver transplantation (LT) is the treatment of end-stage non-alcoholic liver disease (NAFLD), that is decompensated cirrhosis and/or complicated by hepatocellular carcinoma (HCC). Few data on long-term outcome are available. The aim of this study was to evaluate overall patient and graft survivals and associated predictive factors.

METHOD

This retrospective multicentre study included adult transplant patients for NAFLD cirrhosis between 2000 and 2019 in participating French-speaking centres.

RESULTS

A total of 361 patients (69.8% of male) were included in 20 centres. The median age at LT was 62.3 years [57.4-65.9] and the median MELD score was 13.9 [9.1-21.3]; 51.8% of patients had HCC on liver explant. Between 2004 and 2018, the number of LT for NAFLD cirrhosis increased by 720%. A quarter of the patients had cardiovascular history before LT. Median follow-up after LT was 39.1 months [15.8-72.3]. Patient survival at 1, 5 and 10 years after LT was 89.3%, 79.8% and 68.1% respectively. The main causes of death were sepsis (37.5%), malignancies (29.2%) and cardiovascular events (22.2%). In multivariate analysis, three risk factors for overall mortality after LT were recipient pre-LT BMI < 32 kg/m² at LT time (OR: 2.272; p = .012), pre-LT angioplasty during CV check-up (OR: 2.916; p = .016), a combined donor and recipient age over 135 years (OR: 2.020; 95%CI: p = .035).

CONCLUSION

Survival after LT for NAFLD cirrhosis is good at 5 years. Donor and recipient age, and cardiovascular history, are major prognostic factors to consider.

Viability testing during liver preservation

PURPOSE OF REVIEW

Viability assessment is one of the main indications for machine perfusion (MP) in liver transplantation. This review summarizes the rationale, evolution and limitations of proposed viability criteria and suggests a framework for future studies.

RECENT FINDINGS

Liver viability is most frequently assessed during normothermic MP by combining parameters relative to perfusate and bile composition, vascular flows and macroscopic aspect. Assessment protocols are largely heterogeneous and have significantly evolved over time, also within the same group, reflecting the ongoing evolution of the subject. Several recent preclinical studies using discarded human livers or animal models have explored other approaches to viability assessment. During hypothermic MP, perfusate flavin mononucleotide has emerged as a promising biomarker of mitochondrial injury and function. Most studies on the subject suffer from limitations, including low numbers, lack of multicenter validation, and subjective interpretation of some viability parameters.

SUMMARY

MP adds a further element of complexity in the process of assessing the quality of a liver graft. Understanding the physiology of the parameters included in the different assessment protocols is necessary for their correct interpretation. Despite the possibility of assessing liver viability during MP, the importance of donor-recipient matching and operational variables should not be disregarded.

Radiomic analysis of liver grafts from brain-dead donors can predict early allograft dysfunction following transplantation: a proof-of-concept study

BACKGROUND

Selection of liver grafts suitable for transplantation (LT) mainly depends on a surgeon's subjective assessment. This study aimed to investigate the role of radiomic analysis of donor-liver CTs after brain death (DBD) to predict the occurrence of early posttransplant allograft dysfunction (EAD).

METHODS

We retrospectively extracted and analyzed the left lobe radiomic features from CT scans of DBD livers in training and validation cohorts. Multivariate analysis was performed to identify predictors of EAD.

RESULTS

From 126 LTs included in the study in the training cohort, 27 (21.4%) had an EAD. For each patient, 279 radiomic features were extracted of which 5 were associated with EAD (AUC = 0.81) (95% CI 0.72-0.89). Among donor and recipient clinical characteristics, cardiac arrest, steatosis on donor's CT, cold ischemic time and age of recipient were also identified as independent risk factors for EAD. Combined radiomic signature and clinical risk factors showed a strong predictive performance for EAD with a C-index of 0.90 (95% CI 0.84-0.96). A validation cohort of 23 patients confirmed these results.

CONCLUSION

Radiomic signatures extracted from donor CT scan, independently or combined with clinical risk factors is an objective and accurate biomarker for prediction of EAD after LT.

Development of a preoperative score to predict surgical difficulty in liver transplantation

BACKGROUND

A difficulty score to predict intraoperative surgical complexity in liver transplantation has never been developed. The aim of this study was to assess factors associated with a difficult liver transplant and develop a score to predict difficult surgery.

METHODS

All patients undergoing deceased donor whole liver transplantation from 2012 to 2019 at a single center were included. Estimated intraoperative blood loss (mL/kg) and surgery duration (skin-to-arterial reperfusion time) were used as surrogates of difficulty. Based on these variables, the study population was divided into 2 groups: high risk and standard risk of difficulty. Univariate and multivariate analyses were performed to identify predictors associated with a demanding liver transplantation and develop a difficulty score.

RESULTS

A total of 515 patients were included in the study population, and 101 (20%) were considered difficult operations. Patients with a higher risk of difficulty showed a significantly higher rate of Clavien-Dindo ≥III complications (50.5% vs 24.4%, P = .001) and a longer hospital stay (19 vs 16 days, P = .001). Preoperative factors associated with difficulty were retransplantation (odds ratio 4.34, P = .001), preoperative portal vein thrombosis (odds ratio 3.419, P = .001), previous upper abdominal surgery (odds ratio 2.161, P = .003), spontaneous bacterial peritonitis (odds ratio 1.985, P < .02), and prior variceal bleeding (odds ratio 1.401, P = .051). A 10-point difficulty score was created, showing a negative predictive value of 84% at 4 points.

CONCLUSION

Difficult liver transplantation surgery, as assessed by skin-to-arterial reperfusion time and estimated blood loss, is associated with worse perioperative outcomes. We developed a simple score with clinical preoperative variables that predicts difficult surgery, and therefore, it may help to optimize allocation policies and perioperative logistics.

Artificial intelligence for predicting survival following deceased donor liver transplantation: Retrospective multi-center study

BACKGROUND

Previous studies have indicated that the model for end-stage liver disease (MELD) score may fail to predict post-transplantation patient survival. Similarly, other scores (donor MELD score, balance of risk score) that have been developed to predict transplant outcomes have not gained widespread use. These scores are typically derived using linear statistical models. This study aimed to compare the performance of traditional statistical models with machine learning approaches for predicting survival following liver transplantation.

MATERIALS AND METHODS

Data were obtained from 785 deceased donor liver transplant recipients enrolled in the Korean Organ Transplant Registry (2014-2019). Five machine learning methods (random forest, artificial neural networks, decision tree, naïve Bayes, and support vector machine) and four traditional statistical models (Cox regression, MELD score, donor MELD score and balance of risk score) were compared to predict survival.

RESULTS

Among the machine learning methods, the random forest yielded the highest area under the receiver operating characteristic curve (AUC-ROC) values (1-month = 0.80; 3-month = 0.85; and 12-month = 0.81) for predicting survival. The AUC-ROC values of the Cox regression analysis were 0.75, 0.86, and 0.77 for 1-month, 3-month, and 12-month post-transplant survival, respectively. However, the AUC-ROC values of the MELD, donor MELD, and balance of risk scores were all below 0.70. Based on the variable importance of the random forest analysis in this study, the major predictors associated with survival were cold ischemia time, donor ICU stay, recipient weight, recipient BMI, recipient age, recipient INR, and recipient albumin level. As with the Cox regression analysis, donor ICU stay, donor bilirubin level, BAR score, and recipient albumin levels were also important factors associated with post-transplant survival in the RF model. The coefficients of these variables were also statistically significant in the Cox model (p < 0.05). The SHAP ranges for selected predictors for the 12-month survival were (-0.02,0.10) for recipient albumin, (-0.05,0.07) for donor bilirubin and (-0.02,0.25) for recipient height. Surprisingly, although not statistically significant in the Cox model, recipient weight, recipient BMI, recipient age, or recipient INR were important factors in our random forest model for predicting post-transplantation survival.

CONCLUSION

Machine learning algorithms such as the random forest were superior to conventional Cox regression and previously reported survival scores for predicting 1-month, 3-month, and 12-month survival following liver transplantation. Therefore, artificial intelligence may have significant potential in aiding clinical decision-making during liver transplantation, including matching donors and recipients.

Artificial intelligence and liver transplantation: Looking for the best donor-recipient pairing

Decision-making based on artificial intelligence (AI) methodology is increasingly present in all areas of modern medicine. In recent years, models based on deep-learning have begun to be used in organ transplantation. Taking into account the huge number of factors and variables involved in donor-recipient (D-R) matching, AI models may be well suited to improve organ allocation. AI-based models should provide two solutions: complement decision-making with current metrics based on logistic regression and improve their predictability. Hundreds of classifiers could be used to address this problem. However, not all of them are really useful for D-R pairing. Basically, in the decision to assign a given donor to a candidate in waiting list, a multitude of variables are handled, including donor, recipient, logistic and perioperative variables. Of these last two, some of them can be inferred indirectly from the team's previous experience. Two groups of AI models have been used in the D-R matching: artificial neural networks (ANN) and random forest (RF). The former mimics the functional architecture of neurons, with input layers and output layers. The algorithms can be uni- or multi-objective. In general, ANNs can be used with large databases, where their generalizability is improved. However, they are models that are very sensitive to the quality of the databases and, in essence, they are black-box models in which all variables are important. Unfortunately, these models do not allow to know safely the weight of each variable. On the other hand, RF builds decision trees and works well with small cohorts. In addition, they can select top variables as with logistic regression. However, they are not useful with large databases, due to the extreme number of decision trees that they would generate, making them impractical. Both ANN and RF allow a successful donor allocation in over 80% of D-R pairing, a number much higher than that obtained with the best statistical metrics such as model for end-stage liver disease, balance of risk score, and survival outcomes following liver transplantation scores. Many barriers need to be overcome before these deep-learning-based models can be included for D-R matching. The main one of them is the resistance of the clinicians to leave their own decision to autonomous computational models.

Normothermic Regional Perfusion and Hypothermic Oxygenated Machine Perfusion for Livers Donated After Controlled Circulatory Death With Prolonged Warm Ischemia Time: A Matched Comparison With Livers From Brain-Dead Donors

Prolonged warm ischemia time (WIT) has a negative prognostic value in liver transplantation (LT) using grafts procured after circulatory death (DCD). To assess the value of abdominal normothermic regional perfusion (A-NRP) associated with dual hypothermic oxygenated machine perfusion (D-HOPE) in controlled DCD LT, prospectively collected data on LTs performed between January 2016 and July 2021 were analyzed. Outcome of controlled DCD LTs performed using A-NRP + D-HOPE (n = 20) were compared to those performed with grafts procured after brain death (DBD) (n = 40), selected using propensity-score matching. DCD utilization rate was 59.5%. In the DCD group, median functional WIT, A-NRP and D-HOPE time was 43, 246, and 205 min, respectively. Early outcomes of DCD grafts recipients were comparable to those of matched DBD LTs. In DCD and DBD group, incidence of anastomotic biliary complications and ischemic cholangiopathy was 15% versus 22% (p = 0.73) and 5% versus 2% (p = 1), respectively. One-year patient and graft survival was 100% versus 95% (p = 0.18) and 90% versus 95% (p = 0.82). In conclusion, the association of A-NRP + D-HOPE in DCD LT with prolonged WIT allows achieving comparable outcomes to DBD LT.

Outcome of liver transplantation with grafts from brain-dead donors treated with dual hypothermic oxygenated machine perfusion, with particular reference to elderly donors

Prompted by the utilization of extended criteria donors, dual hypothermic oxygenated machine perfusion (D-HOPE) was introduced in liver transplantation to improve preservation. When donors after neurological determination of death (DBD) are used, D-HOPE effect on graft outcomes is unclear. To assess D-HOPE value in this setting and to identify ideal scenarios for its use, data on primary adult liver transplant recipients from January 2014 to April 2021 were analyzed using inverse probability of treatment weighting, comparing outcomes of D-HOPE-treated grafts (n = 121) with those preserved by static cold storage (n = 723). End-ischemic D-HOPE was systematically applied since November 2017 based on donor and recipient characteristics and transplant logistics. D-HOPE use was associated with a significant reduction of early allograft failure (OR: 0.24; 0.83; p = .024), grade ≥3 complications (OR: 0.57; p = .046), comprehensive complication index (-7.20 points; p = .003), and improved patient and graft survival. These results were confirmed in the subset of elderly donors (>75-year-old). Although D-HOPE did not reduce the incidence of biliary complications, its use was associated with a reduced severity of ischemic cholangiopathy. In conclusion, D-HOPE improves postoperative outcomes and reduces early allograft loss in extended criteria DBD grafts.

Development of a risk score model for 1‐year graft loss after adult deceased donor liver transplantation in Japan based on a 20‐year nationwide cohort

Aim

Using nationwide data collected over the past 20 years, we aimed to investigate deceased donor liver transplantation (DDLT) outcomes to develop a unique risk model that can be used to establish a standard for organ acceptance in Japan.

Methods

Data were collected for 449 recipients aged ≥18 years who underwent DDLT between 1999 and 2019. Least absolute shrinkage and selection operator (LASSO) regression analysis was utilized to develop an original risk score model for 1‐year graft loss (termed the Japan Risk Index [JRI]). We developed risk indices according to recipient, donor, and surgery components (termed JRI‐R, D, and S, respectively). The JRI was validated via a 5‐fold cross‐validation. We also compared DDLT outcomes and risk indices among Era1 (−2011), Era2 (−2015), and Era3 (−2019).

Results

The 1‐year graft survival rate was 89.5% and improved significantly, reaching 84.7%, 87.6%, and 93.9% in Era1, Era2, and Era3, respectively. The JRI was calculated as JRI‐R (re‐transplantation, Model for End‐Stage Liver Disease score, medical condition in intensive care unit) × JRI‐D (age, catecholamine index, maximum sodium, maximum total bilirubin) × JRI‐S (total ischemic time) × 0.84. The risk model achieved a mean C‐statistic value of 0.81 in the validation analysis. The risk index was significantly lower in Era3 than in Era2.

Conclusion

Changes in the risk index over time indicated that avoiding risks contributed to the improved outcomes in Era3. The JRI is unique to adult DDLT in Japan and may be useful as a reference for organ acceptance in the future.

Development of a Novel Prognostic Nomogram for High Model for End-Stage Liver Disease Score Recipients Following Deceased Donor Liver Transplantation

Background

A high model of end-stage liver disease (MELD) score (>30) adversely affects outcomes even if patients receive prompt liver transplantation (LT). Therefore, balanced allocation of donor grafts is indispensable to avoid random combinations of donor and recipient risk factors, which often lead to graft or recipient loss. Predictive models aimed at avoiding donor risk factors in high-MELD score recipients are urgently required to obtain satisfactory outcomes.

Method

Data of patients with MELD score >30 who underwent LT at three transplantation institutes between 2015 and 2018 were retrospectively reviewed. Early allograft dysfunction (EAD), length of intensive care unit (ICU) stay, and graft loss were recorded. Corresponding independent risk factors were analyzed using stepwise multivariable regression analysis. A prediction model of graft loss was developed, and discrimination and calibration were measured.

Results

After applying the exclusion criteria, 778 patients were enrolled. The incidence of EAD was 34.8% (271/778). Donor graft macrovesicular steatosis, graft-to-recipient weight ratio (GRWR), warm ischemia time (WIT), cold ischemia time (CIT), and ABO blood incompatibility, together with donor serum albumins, were independent predictors of EAD. The incidence of ICU stay over 10 days was 64.7% (503/778). Donor age, recipient's MELD score, Child score, and CIT were independent predictors of ICU stay. The 3-year graft survival rates (GSRs) in the training and validation cohorts were 64.2 and 59.3%, respectively. The independent predictors of graft loss were recipient's Child score, ABO blood type incompatibility, donor serum total bilirubin over 17.1 μmol/L, and cold CIT. A nomogram based on these variables was internally and externally validated and showed good performance (area under the receiver operating characteristic curve = 70.8 and 66.0%, respectively). For a recipient with a high MELD score, the avoidance of ABO blood type incompatibility and CIT ≥6 h would achieve a 3-year GSR of up to 78.4%, whereas the presence of the aforementioned risk factors would decrease the GSR to 35.4%.

Conclusion

The long-term prognosis of recipients with MELD scores >30 could be greatly improved by avoiding ABO blood type incompatibility and CIT ≥6 h.

Artificial intelligence and human liver allocation: Potential benefits and ethical implications

Since its implementation almost two decades ago, the urgency allocation policy has improved the survival of patients on the waiting list for liver transplantation worldwide. The Model for End-Stage Liver Disease score is widely used to predict waiting list mortality. Due to some limitations related to its use, there is an active investigation to develop other prognostic scores. Liver allocation (LA) entails complex decision-making, and grafts are occasionally not directed to the recipients who are more likely to survive. Prognostic scores have, thus far, failed to predict post-operatory survival. Furthermore, the increasing use of marginal donors is associated with worse outcomes. Adequate donor-recipient pairing could help avoid retransplantation or futile procedures and reduce postoperative complications, mortality, hospitalization time, and costs. Artificial intelligence has applications in several medical fields. Machine learning algorithms (MLAs) use large amounts of data to detect unforeseen patterns and complex interactions between variables. Artificial neural networks and decision trees were the most common forms of MLA tested on LA. Some researchers have shown them to be superior for predicting waiting list mortality and graft failure than conventional statistical methods. These promising techniques are increasingly being considered for implementation.

BAR Score Performance in Predicting Survival after Living Donor Liver Transplantation: A Single-Center Retrospective Study

METHODS

146 adult liver transplant recipients were included. Univariate and multivariate analyses were used to determine the independent predictors of survival at 3 months, 1 year, and 5 years. The receiver operating characteristic (ROC) curve for the BAR score was plotted, and the area under the ROC curve (AUROC) was calculated. Kaplan-Meier curve and log-rank test were used to compare survival above and below the best cutoff values.

RESULTS

The mean age was 52.45 ± 8.54 years, and 59.6% were males. The survival rates were 89, 78.8, and 72% at 3 months, 1 year, and 5 years, respectively. The BAR score demonstrated a clinically significant value in the prediction of 3-month (AUROC = 0.89), 1-year (AUROC = 0.76), and 5-year survival (AUROC = 0.71). Among the investigated factors associated with survival, BAR score <10 points was the only independent predictor of 3-month (OR 7.34, p < 0.0001), 1-year (OR 3.37, p=0.001), and 5-year survival (OR 2.83, p=0.044).

CONCLUSIONS

BAR is a simple and easily applicable scoring system that could significantly predict short- and long-term survival after LDLT. A large multicenter study is warranted to validate our results in the Egyptian population.

Liver Transplantation for Hepatocellular Carcinoma: How Should We Improve the Thresholds?

Simple Summary

The ideal treatment for hepatocellular carcinoma (HCC) is liver transplantation (LT), which both eliminates the HCC and cures the diseased liver. Once considered an experimental treatment with dismal survival rates, LT for HCC entered a new era with the establishment of the Milan criteria over 20 years ago. However, over the last two decades, the Milan criteria, which are based on tumor morphology, have come under intense scrutiny and are now largely regarded as too restrictive, and limit the access of transplantation for many patients who would otherwise achieve good clinical outcomes. The liver transplant community has been making every effort to reach a goal of establishing more reliable selection criteria. This article addresses how the criteria have been extended, as well as the concept of pre-transplant down-staging to maximize the eligibility.

Abstract

Hepatocellular carcinoma (HCC) is the third highest cause of cancer-related mortality, and liver transplantation is the ideal treatment for this disease. The Milan criteria provided the opportunity for HCC patients to undergo LT with favorable outcomes and have been the international gold standard and benchmark. With the accumulation of data, however, the Milan criteria are not regarded as too restrictive. After the implementation of the Milan criteria, many extended criteria have been proposed, which increases the limitations regarding the morphological tumor burden, and incorporates the tumor’s biological behavior using surrogate markers. The paradigm for the patient selection for LT appears to be shifting from morphologic criteria to a combination of biologic, histologic, and morphologic criteria, and to the establishment of a model for predicting post-transplant recurrence and outcomes. This review article aims to characterize the various patient selection criteria for LT, with reference to several surrogate markers for the biological behavior of HCC (e.g., AFP, PIVKA-II, NLR, 18F-FDG PET/CT, liquid biopsy), and the response to locoregional therapy. Furthermore, the allocation rules in each country and the present evidence on the role of down-staging large tumors are addressed.

Improving Matching Between Recipient and Donor in Liver Transplantation: Are Scores Able to Predict Long-term Survival?

BACKGROUND

The primary goal was to calculate the value of delta Model for End-Stage Liver Disease (D-MELD) and Balance of Risk (BAR) scores in patients who underwent liver transplant. The secondary objective was to evaluate D-MELD and BAR scores' ability to predict patient and graft survival.

METHODS

We retrospectively evaluated 336 patients who underwent liver transplant in a tertiary medical center between January 2010 and December 2020. The D-MELD and the BAR scores were evaluated through a receiver operating characteristic curve with the calculation of area under the curve (AUC) to evaluate the predictive score power for 3-month, 6-month, 1-year, and 5-year patient and graft survivals.

RESULTS

The AUCs of D-MELD score in predicting 5-year patient and graft survival were 0.506 (95% CI, 0.43-0.57) and 0.49 (95% CI, 0.42-0.56), respectively. The AUCs of BAR score in predicting 5-year patient and graft survival were 0.50 (95% CI, 0.33-0.66) and 0.49 (95% CI, 0.30-0.67), respectively.

CONCLUSIONS

We could not confirm the ability to predict long-term survival by using D-MELD and BAR scores in our sample; however, there is a statistically significant trend in receiver operating characteristic curves of 5-year patient and graft survivals. We encourage the use of new scoring systems with a greater external validation to improve allograft allocation.

The impact of hepatitis C virus direct acting agents in liver transplant using very old donor grafts: a real-world single-center analysis

The correct timing of use of direct acting agents (DAAs) among transplanted patients remains unknown. The aim of this paperwork is to evaluate the impact of DAAs treatment in pre- or peri-operative period in liver transplantation when grafts ≥ 70 years are used. This is a retrospective analysis comparing adult liver transplant performed for HCV-related cirrhosis and/or hepatocarcinoma using a graft ≥ 70 in the period 2015-2018 (Group DAA-HCV-OLD, study group) to three different groups: (a) anti-HCV-Ab-negative patients receiving graft ≥ 70 (no-HCV-OLD), (b) anti-HCV-Ab-negative patients receiving a graft aged 18-69 years (no-HCV-YOUNG), and (c) anti-HCV-Ab-positive patients receiving a donor graft ≥ 70 in the period 2007-2011 (no-DAA-HCV-OLD). Totally, 528 liver transplants were considered: 164 in DAA-HCV-OLD, 143 in no-HCV-OLD, 120 in no-HCV-YOUNG and 101 in no-DAA-HCV-OLD Group. Graft survival rates at 1 and 3 years were 88% and 81% in DAA-HCV-OLD Group, 82% and 68% in no-DAA-HCV-OLD (p = 0.007), 89% and 84% in no-HCV-OLD (p = 0.76), and 94% and 92% in no-HCV-YOUNG (p = 0.02). No differences were observed among groups in the incidence of primary non-function, primary dysfunction, vascular or biliary complications. DAAs were able to zero HCV-related graft loss, with a 3-year graft survival > 80%. The outcomes of older graft recipients became equal irrespectively of their HCV serological status.

The Need to Update Endpoints and Outcome Analysis in the Rapidly Changing Field of Liver Transplantation

Liver transplantation (LT) survival rates have continued to improve over the last decades, mostly due to the reduction of mortality early after transplantation. The advancement is facilitating a liberalization of access to LT, with more patients with higher risk profiles being added to the waiting list. At the same time, the persisting organ shortage fosters strategies to rescue organs of high-risk donors. This is facilitated by novel technologies such as machine perfusion. Owing to these developments, reconsideration of the current and emerging endpoints for the assessment of the efficacy of existing and new therapies is warranted. While conventional early endpoints in LT have focused on the damage induced to the parenchyma, the fate of the bile duct and the recurrence of the underlying disease have a stronger impact on the long-term outcome. In light of this evolving landscape, we here attempt to reflect on the appropriateness of the currently used endpoints in the field of LT trials.

Liver transplantation: survival and indexes of donor-recipient matching

OBJECTIVE

The aim of this study was to determine the prospective capacity and impact of donor risk index, preallocation survival outcomes following liver transplant, donor model for end-stage liver disease, and balance of risk on patients' 30-day survival after liver transplantation.

METHODS

We prospectively analyzed patient survival in a multicentric observational cohort of adult liver transplantation through the year of 2019 at the state of Paraná, Brazil. The receiver operating characteristic curve, the area under the curve, and the best cutoff point (i.e., the Youden's index) were estimated to analyze the prognostic value of each index.

RESULTS

In total, 252 liver transplants were included with an average model for end-stage liver disease score of 21.17 and a 30-day survival of 79.76%. The donor risk index was the only prognostic variable with no relation to patients' 30-day mortality model for end-stage liver disease and donor model for end-stage liver disease have no prognostic value on receiver operating characteristic curve, but preallocation survival outcomes following liver transplant, survival outcomes following liver transplant, and balance of risk presented good relationship with this observation. The cutoff value was estimated in 11-12 points for balance of risk and 9-12 for preallocation survival outcomes following liver transplant and survival outcomes following liver transplant. The 30-day survival for the group of transplants with scores up to 12 points (n=172) in all the three indexes was 87.79%, and for those transplants with scores higher than 12 it was 36.36%.

CONCLUSIONS

The 30-day survival is 79.76%, and balance of risk, survival outcomes following liver transplant, and preallocation survival outcomes following liver transplant are the good prognostic indexes. The cutoff value of 12 points has clinical usefulness to predict the post-liver transplantation results.

A New Dawn for the Use of Artificial Intelligence in Gastroenterology, Hepatology and Pancreatology

Artificial intelligence (AI) is rapidly becoming an essential tool in the medical field as well as in daily life. Recent developments in deep learning, a subfield of AI, have brought remarkable advances in image recognition, which facilitates improvement in the early detection of cancer by endoscopy, ultrasonography, and computed tomography. In addition, AI-assisted big data analysis represents a great step forward for precision medicine. This review provides an overview of AI technology, particularly for gastroenterology, hepatology, and pancreatology, to help clinicians utilize AI in the near future.

Limitations of current liver donor allocation systems and the impact of newer indications for liver transplantation

Liver transplantation represents a life-saving treatment for patients with decompensated cirrhosis, a severe condition associated with a high risk of waiting list mortality. When decompensation occurs rapidly in the presence of extrahepatic organ failures, the condition is called acute-on-chronic liver failure, which is associated with an even higher risk of death, though liver transplantation can also markedly improve survival in affected patients. However, there are still gaps in our understanding of how to optimise prioritisation and organ allocation, as well as survival among patients with acute-on-chronic liver failure (both before and after transplant). Moreover, it is urgent to address inequalities in access to liver transplantation in patients with severe alcoholic hepatitis and non-alcoholic steatohepatitis. Several controversies still exist regarding gender and regional disparities, as well as the use of suboptimal donor grafts. In this review, we aim to provide a critical perspective on the role of liver transplantation in patients with decompensated cirrhosis and address areas of ongoing uncertainty.

Combining Donor and Recipient Age With Preoperative MELD and UKELD Scores for Predicting Survival After Liver Transplantation

OBJECTIVES

The end-stage liver disease scoring systems MELD, UKELD, and D-MELD (donor age × MELD) have had mediocre results for survival assessment after orthotopic liver transplant. Here, we introduced new indices based on preoperative MELD and UKELDscores and assessed their predictive ability on survival posttransplant.

MATERIALS AND METHODS

We included 1017 deceased donor orthotopic liver transplants that were performed between 2008 (the year UKELD was introduced) and 2019. Donor and recipient characteristics, liver disease scores, transplant characteristics, and outcomes were collected for analyses. D-MELD, D-UKELD (donor age × UKELD),DR-MELD[(donor age + recipient age) × MELD], and DR-UKELD [(donor age + recipient age) × UKELD] were calculated.

RESULTS

No score had predictive value for graft survival. For patient survival,DR-MELD and DR-UKELD provided the best results but with low accuracy. The highest accuracy was observed at 1 year posttransplant (areas under the curve of 0.598 [95% CI, 0.529-0.667] and 0.609 [95% CI, 0.549-0.67]forDR-MELDandDR-UKELD). Addition of donor and recipient age significantly improved the predictive abilities of MELD and UKELD for patient survival, but addition of donor age alone did not. For 1-year mortality (using receiver operating characteristic curves), optimal cut-off points were DR-MELD>2345 and DR-UKELD>5908. Recipients with DR-MELD >2345 (P < .001) and DR-UKELD >5908 (P = .002) had worse patient survival within the first year, but only DR-MELD >2345 remained significant after multivariable analysis (P = .007).

CONCLUSIONS

DR-MELD and DR-UKELD scores provided the best, albeit mediocre, predictive ability among the 6 tested models, especially at 1 year after posttransplant, although only for patient but not for graft survival. A DR-MELD >2345 was considered to be an additional independent risk factor for worse recipient survival within the first postoperative year.

The liver transplant risk score prognosticates the outcomes of liver transplant recipients at listing

BACKGROUND

We assessed if the risk of post-liver transplant mortality within 24 h could be stratified at the time of listing using the liver transplant risk score (LTRS). Secondary aims were to assess if the LTRS could stratify the risk of 30-day, 1-year mortality, and survival beyond the first year.

METHODS

MELD, BMI, age, diabetes, and the need for dialysis were the five variables used to calculate the LTRS during patients' evaluation for liver transplantation. Mortality rates at 24 h, 30 days, and 1-year were compared among groups of patients with different LTRS. Patients with ABO-incompatibility, redo, multivisceral, partial graft and malignancies except for hepatocellular carcinoma were excluded. Data of 48,616 adult liver transplant recipients were extracted from the Scientific Registry of Transplant Recipients between 2002 and 2017.

RESULTS

24-h mortality was 0.9%, 1.0%, 1.1%, 1.7%, 2.3%, 2.0% and 3.5% for patients with LTRS of 0,1,2,3,4, 5 and ≥ 6, respectively (P < 0.001). 30-day mortality was 3.5%, 4.2%, 4.9%, 6.2%, 7.6%, 7.2% and 10.1% respectively (P < 0.001). 1-year mortality was 8.6%, 10.8%, 12.9%, 13.9%, 18.5%, 20.3% and 28.6% respectively (P < 0.001). 10-year survival was 61%, 56%, 57%, 54%, 47%, and 31% for patients with 0, 1, 2, 3, 4, 5 and ≥ 6 points respectively (P < 0.001).

CONCLUSION

Perioperative mortality and long-term survival of patients undergoing LT can be accurately estimated at the time of listing by the LTRS.

Impact of donor age on liver transplant outcomes in patients with hepatocellular carcinoma: analysis of the SRTR database

Background

Donor age is an important predictor for liver transplant recipients. Studies have not fully explored its impact on transplant outcomes in hepatocellular carcinoma (HCC) patients as well as its involvement in tumor recurrence.

Methods

HCC patients who received liver transplants during 2010–2017 from the Scientific Registry of Transplant Recipients database were included. The recipients were divided into four groups based on donor age: I (≤ 34 years), II (35–49 years), III (50–64 years), and IV (≥ 65 years). Transplant outcomes, including the overall survival (OS), tumor recurrence, and risks, were evaluated.

Results

A total of 13,276 HCC recipients were included in this study. Statistical significant differences were observed in OS among the four groups. The best 5-year survival was 76.0% in group I, followed by 73.5% in group II, 72.8% in group III, and 69.2% in group IV (P < 0.001). However, the liver-specific survival did not differ among these groups (P = 0.260). Donor age was found to be the independent predictor of OS after adjusting for other variables (P < 0.001, ref. group I; 1.087 (0.979–1.208) for group II, P = 0.119; 1.124 (1.015–1.246) for group III, P = 0.025; 1.395 (1.215–1.602) for group IV, P < 0.001). In subgroup analysis, OS was significantly different in recipients with hepatitis C virus (HCV), but there was no significant difference for recipients with hepatitis B virus (HBV), alcoholic liver diseases and nonalcoholic steatohepatitis (NASH). The post-transplant cumulative tumor recurrence rates were similar among the four groups (P = 0.382).

Conclusions

Older donor age was associated with decreased OS but not liver-specific survival as well as post-transplant tumor recurrence in HCC recipients. Donor age also had different effects in patients with different underlying liver diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01786-6.

A nomogram to predict survival in patients with acute-on-chronic hepatitis B liver failure after liver transplantation

BACKGROUND

Individualized prediction of survival after liver transplantation (LT) for patients with hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) has not been well investigated. This study aimed to develop a prognostic nomogram for patients with HBV-ACLF undergoing LT.

METHODS

The nomogram was derived from a retrospective study of 290 patients who underwent LT for HBV-ACLF at the Third Affiliated Hospital of Sun Yat-sen University between January 2012 and December 2017. Concordance index and determiner calibration curve was used to ascertain the predictive accuracy and discriminative ability of the nomogram. The predictive performance of the nomogram was compared with that of Child-Pugh score, model for end-stage liver disease (MELD), MELD-Na, chronic liver failure Consortium Organ Failure score (CLIF-C OFs), and CLIF-C ACLF.

RESULTS

The 1-year mortality rate was 23.1% (67/290). The Cox multivariate analysis showed that risk factors for 1-year survival rate included white blood cell count, alanine aminotransferase/aspartate aminotransferase ratio, and the organ failure numbers. The determiner calibration curve showed good agreement between prediction of the nomogram and actual observation. The concordance index of the nomogram for predicting 1-year survival was 0.707, which was significantly higher than that of other prognostic models: Child-Pugh score (0.626), MELD (0.627), MELD-Na (0.583), CLIF-C OF (0.674), and comparable to that of CLIF-C ACLF (0.684).

CONCLUSIONS

Our study developed a novel nomogram that could accurately predict individualized post-transplantation survival in patients with HBV-ACLF. The nomogram might be a useful tool for identifying HBV-ACLF patients who would benefit from LT.

Changing Trends in Liver Transplantation: Challenges and Solutions

Despite improvements in postliver transplant outcomes through refinements in perioperative management and surgical techniques, several changing trends in liver transplantation have presented challenges. Mortality on the waitlist remains high. In the United States, Europe, and the United Kingdom, there is an increasing need for liver transplantation, primarily as a result of increased incidence of nonalcoholic steatohepatitis-related cirrhosis and cancer indications. Meanwhile, donor suitability has decreased, as donors are often older and have more comorbidities. Despite a mismatch between organ need and availability, many organs are discarded. Notwithstanding this, many solutions have been developed to overcome these challenges. Innovative techniques in allograft preservation, viability assessment, and reconditioning have allowed the use of suboptimal organs with adequate results. Refinements in surgical procedures, including live donor liver transplantations, have increased the organ pool and are decreasing the time and mortality on the waitlist. Despite many challenges, a similar number of solutions and prospects are on the horizon. This review seeks to explore the changing trends and challenges in liver transplantation and highlight possible solutions and future directions.

Preoperative Stratification of Liver Transplant Recipients: Validation of the LTRS

BACKGROUND

The liver transplant risk score (LTRS) was developed to stratify 90-day mortality of patients referred for liver transplantation (LT). We aimed to validate the LTRS using a new cohort of patients.

METHODS

The LTRS stratifies the risk of 90-day mortality of LT recipients based on their age, body mass index, diabetes, model for end-stage liver disease (MELD) score, and need for dialysis. We assessed the performance of the LTRS using a new cohort of patients transplanted in the United States between July 2013 and June 2017. Exclusion criteria were age <18 years, ABO incompatibility, redo or multivisceral transplants, partial grafts, malignancies other than hepatocellular carcinoma and fulminant hepatitis.

RESULTS

We found a linear correlation between the number of points of the LTRS and 90-day mortality. Among 18 635 recipients, 90-day mortality was 2.7%, 3.8%, 5.2%, 4.8%, 6.7%, and 9.3% for recipients with 0, 1, 2, 3, 4, and ≥5 points (P < 0.001). The LTRS also stratified 1-year mortality that was 5.5%, 7.7%, 9.9%, 9.3%, 10.8%, and 15.4% for 0, 1, 2, 3, 4, and ≥5 points (P < 0.001). An inverse correlation was found between the LTRS and 4-year survival that was 82%, 79%, 78%, 82%, 78%, and 66% for patients with 0, 1, 2, 3, 4, and ≥5 points (P < 0.001). The LTRS remained an independent predictor after accounting for recipient sex, ethnicity, cause of liver disease, donor age, cold ischemia time, and waiting time.

CONCLUSIONS

The LTRS can stratify the short- and long-term outcomes of LT recipients at the time of their evaluations irrespective of their gender, ethnicity, and primary cause of liver disease.

Impact of Donor Age on the Outcome of Living-donor Liver Transplantation: Special Consideration to the Feasibility of Using Elderly Donors

BACKGROUND

The use of elderly donors (≥60 y) in living-donor liver transplantation (LDLT) remains controversial. In this study, we aimed to determine the safety of surgery for elderly donors and the impact of donor age on LDLT outcomes.

METHODS

We, retrospectively, reviewed 470 cases of LDLT at Kumamoto University Hospital from December 1998 to March 2017.

RESULTS

Donors were divided into 5 groups according to age: 20-29 (n = 109), 30-39 (n = 157), 40-49 (n = 87), 50-59 (n = 81), and ≥60 (n = 36). At our institution, elderly donor candidates required additional preoperative work-up. There were no significant differences in the incidence of postoperative complications and duration of postoperative hospital stay among the 5 donor groups. Regardless of graft type, elderly donors were comparable to younger donor groups (<30 y) in postoperative recovery of liver function. Risk-adjusted overall survival rates of recipients among donor groups were not significantly different. Additionally, donor age was not significantly associated with 6-month graft survival of adult and pediatric recipients.

CONCLUSIONS

Elderly candidates ≥60 years of age can safely be selected as LDLT donors after meticulous preoperative work-up.

The Impact of Portal Vein Thrombosis on Liver Transplant Outcomes: Does Grade or Flow Rate Matter?

BACKGROUND

Portal vein thrombosis (PVT) makes the technical aspect of liver transplantation challenging and also affects outcomes. Our aim was to study impact of PVT grade and postreperfusion portal flow on posttransplant outcomes.

METHODS

Patients who underwent transplantation with PVT between January 2007 and May 2017 were selected (n = 126). Data on grade of PVT and portal vein flow were collected. Patients were classified into 2 groups; low grade (Yerdel Grade I, n = 73) and high grade (Yerdel Grade II or III, n = 53). Using portal flow rate, patients were divided into high flow (≥1000 mL/min, n = 95) and low flow (<1000 mL/min, n = 31). Additional analyses of flow by graft weight and complications were performed.

RESULTS

Postoperatively, incidence of biliary strictures were significantly greater in high-grade PVT compared with low grade (P = 0.02). Incidence of postoperative portal vein thrombosis was higher in low flow after reperfusion compared with high flow (P = 0.02), as was bile leak (P = 0.02). On identifying factors associated with graft loss, moderate to severe ascites preoperatively, high PVT grade and bile leak were associated with worse graft survival. Subanalysis performed combining grade and flow showed that low grade, high flow had the highest graft survival while high grade, low flow had the lowest (P = 0.006). High-grade PVT with low flow also appeared to be an independent risk factor for biliary complications (P = 0.01).

CONCLUSIONS

In conclusion, biliary complications, especially strictures are more common in high-grade PVT and graft survival is worse in high-grade PVT and low portal flow.

Adult split liver transplantation: A PRISMA-compliant Chinese single-center retrospective case-control study

Although pediatric split liver transplantation (SLT) has been proven safe and the waitlist mortality rate has been successfully reduced, the safety of adult SLT has not been confirmed.Using 1:2 matching, 47 recipients who underwent adult SLT were matched to 94 of 743 recipients who underwent adult whole graft liver transplantation (WGLT). Eventually, 141 recipients were included in the case-control study. Subgroup analysis of 43 recipients in the SLT group was performed based on the presence of the middle hepatic vein (MHV) in the grafts.No significant differences in 5-year survival (80.8% vs 81.6%, P = .465) were observed between the adult SLT and WGLT groups. However, compared to recipients in the WGLT group, those in the SLT group had more Clavien-Dindo grade III-V complications, longer hospitalization duration, and higher mortality within 45 days. Furthermore, on multivariate analysis, 45-day postoperative mortality in recipients in the SLT group was mainly affected by hyperbilirubinemia within postoperative day (POD) 7-14, surgery time, and intraoperative blood loss. Subgroup analysis showed no significant differences in hyperbilirubinemia within POD 7-14, complications, and survival rate between SLTMHV(+) and SLTMHV [-].Adult SLT is safe and effective based on long-term survival rates; however, a reduction in the incidence of short-term complications is required. Non-obstructive hyperbilirubinemia within POD 7 to 14 is an independent predictor of short-term mortality after SLT.