Characteristics associated with liver graft failure: the concept of a donor risk index

Liver Transplantation Outcomes From Controlled Circulatory Death Donors: Static cold storage vs in situ normothermic regional perfusion vs ex situ normothermic machine perfusion

OBJECTIVE

To compare the outcomes of livers donated after circulatory death (DCD) and undergoing either in situ normothermic regional perfusion (NRP) or ex situ normothermic machine perfusion (NMP) with livers undergoing static cold storage (SCS).

SUMMARY OF BACKGROUND DATA

DCD livers are associated with increased risk of primary nonfunction, poor function, and nonanastomotic strictures (NAS), leading to underutilization.

METHODS

A single center, retrospective analysis of prospectively collected data on 233 DCD liver transplants performed using SCS, NRP, or NMP between January 2013 and October 2020.

RESULTS

Ninety-seven SCS, 69 NRP, and 67 NMP DCD liver transplants were performed, with 6-month and 3-year transplant survival (graft survival noncensored for death) rates of 87%, 94%, 90%, and 76%, 90%, and 76%, respectively. NRP livers had a lower 6-month risk-adjusted Cox proportional hazard for transplant failure compared to SCS (hazard ratio 0.30, 95%CI 0.08-1.05, P = 0.06). NRP and NMP livers had a risk-adjusted estimated reduction in the mean model for early allograft function score of 1.52 (P < 0.0001) and 1.19 (P < 0.001) respectively compared to SCS. Acute kidney injury was more common with SCS (55% vs 39% NRP vs 40% NMP; P = 0.08), with a lower risk-adjusted peak-to-baseline creatinine ratio in the NRP (P = 0.02). No NRP liver had clinically significant NAS in contrast to SCS (14%) and NMP (11%, P = 0.009), with lower risk-adjusted odds of overall NAS development compared to SCS (odds ratio = 0.2, 95%CI 0.06-0.72, P = 0.01).

CONCLUSION

NRP and NMP were associated with better early liver function compared to SCS, whereas NRP was associated with superior preservation of the biliary system.

Expedited evaluation for liver transplantation: A critical look at processes and outcomes

BACKGROUND

Most patients are listed for liver transplant (LT) following extensive workup as outpatients ("conventional evaluation"). Some patients undergo urgent evaluation as inpatients after being transferred to a transplant center ("expedited evaluation"). We hypothesized that expedited patients would have inferior survival due to disease severity at the time of transplant and shorter workup time.

METHODS

Patients who underwent evaluation for LT at our institution between 2012 and 2016 were retrospectively reviewed. The expedited and conventional cohorts were defined as above. Living donor LT recipients, combined liver-kidney recipients, acute liver failure patients, and re-transplant patients were excluded. We compared patient characteristics and overall survival between patients who received a transplant following expedited evaluation and those who did not, and between LT recipients based on expedited or conventional evaluation.

RESULTS

Five-hundred and nine patients were included (110 expedited, 399 conventional). There was no difference in graft or patient survival at 1 year for expedited versus conventional LT recipients. In multivariable analysis of overall survival, only Donor Risk Index (HR 1.97, CI 1.04-3.73, P = .037, per unit increase) was associated with increased risk of death.

CONCLUSIONS

Patients who underwent expedited evaluation for LT had significant demographic and clinical differences from patients who underwent conventional evaluation, but comparable post-transplant survival.

The Effect of Acuity Circles on Deceased Donor Transplant and Offer Rates Across Model for End-Stage Liver Disease Scores and Exception Statuses

Acuity circles (AC), the new liver allocation system, was implemented on February 4, 2020. Difference-in-differences analyses estimated the effect of AC on adjusted deceased donor transplant and offer rates across Pediatric End-Stage Liver Disease (PELD) and Model for End-Stage Liver Disease (MELD) categories and types of exception statuses. The offer rates were the number of first offers, top 5 offers, and top 10 offers on the match run per person-year. Each analysis adjusted for candidate characteristics and only used active candidate time on the waiting list. The before-AC period was February 4, 2019, to February 3, 2020, and the after-AC period was February 4, 2020, to February 3, 2021. Candidates with PELD/MELD scores 29 to 32 and PELD/MELD scores 33 to 36 had higher transplant rates than candidates with PELD/MELD scores 15 to 28 after AC compared with before AC (transplant rate ratios: PELD/MELD scores 29-32, _2.34 3.32_4.71 ; PELD/MELD scores 33-36, _1.70 2.51_3.71 ). Candidates with PELD/MELD scores 29 or higher had higher offer rates than candidates with PELD/MELD scores 15 to 28, and candidates with PELD/MELD scores 29 to 32 had the largest difference (offer rate ratios [ORR]: first offers, _2.77 3.95_5.63 ; top 5 offers, _3.90 4.39_4.95 ; top 10 offers, _4.85 5.30_5.80 ). Candidates with exceptions had lower offer rates than candidates without exceptions for offers in the top 5 (ORR: hepatocellular carcinoma [HCC], _0.68 0.77_0.88 ; non-HCC, _0.73 0.81_0.89 ) and top 10 (ORR: HCC, _0.59 0.65_0.71 ; non-HCC, _0.69 0.75_0.81 ). Recipients with PELD/MELD scores 15 to 28 and an HCC exception received a larger proportion of donation after circulatory death (DCD) donors after AC than before AC, although the differences in the liver donor risk index were comparatively small. Thus, candidates with PELD/MELD scores 29 to 34 and no exceptions had better access to transplant after AC, and donor quality did not notably change beyond the proportion of DCD donors.

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.

The Practice of Retransplantation for Recurrent Alcohol-associated Liver Disease in the United States Is Uncommon With Acceptable Outcomes

Alcohol-associated liver disease (ALD) is the leading indication for liver transplantation (LT) in the United States. Alcohol use disorder relapse can lead to graft failure and the need for liver retransplantation (re-LT). Despite the rising incidence of LT for ALD, the practice of re-LT for recurrent ALD is not well understood. We aimed to define the practice of re-LT for recurrent ALD during the last 20 y.

METHODS

Using the US national transplant registry, adults who underwent re-LT for recurrent ALD were compared with LT recipients who died from recurrent ALD and propensity score-matched re-LT recipients with non-ALD indications. All groups had at least 1-y survival of their primary graft. Kaplan-Meier analysis was used to calculate 1- and 5-y survivals.

RESULTS

Between 2000 and 2020, 74 re-LTs were performed for recurrent ALD (1.0% of all re-LTs). There was an increase in recurrent ALD re-LT practice from 2017 to 2020 versus 2014 to 2016 (20 versus 2). At the time of re-LT, patients with recurrent ALD had a significant decrease in body mass index (median 25.1 versus 28.8 kg/m²; P < 0.001) versus the index LT. Patient and graft survivals were similar between patients who underwent re-LT for ALD and non-ALD (56.4% versus 56.9% 5-y graft survival, P = 0.96; 62.8% versus 59.0% 5-y patient survival, P = 0.58).

CONCLUSIONS

The practice of re-LT for recurrent ALD is uncommon in the United States. Graft and patient survivals seem to be acceptable and support the occasional practice of re-LT for recurrent ALD should the patient be deemed an appropriate candidate.

Impact of the Kasai Procedure and the Length of Native Liver Survival Time on Outcomes of Liver Transplantation for Biliary Atresia

The aim is to explore the impact of the Kasai procedure (KP) and the length of native liver survival time (NLST) on outcomes of liver transplantation (LT). Patients with biliary atresia (BA), who underwent LT in Beijing Friendship Hospital from January 2017 to December 2019, were enrolled and divided into non-KP (N-KP) and post-KP (P-KP) groups. The patients in the P-KP group were further divided into early failure (KP-EF) defined by NLST <1 year, medium failure (KP-MF, NLST 1-5 years), and late failure (KP-LF, NLST >5 years) subgroups. Clinical data at baseline and during follow-up were collected. The inverse probability of treatment weighting method was used to evaluate the independent effect of KP and the length of NLST on clinical outcomes. Among 197 patients with BA, the N-KP group accounted for 43 (21.8%), KP-EF 71 (46.1%), KP-MF 59 (38.3%), and KP-LF 24 (15.6%) cases, respectively. The N-KP and KP-EF groups had significantly longer hospitalization and intensive care unit stays after LT. Graft and overall survival rates were 93.0% in the N-KP group and 97.4% in P-KP group, respectively. The mortality rate in the P-KP group were significantly lower compared with that of the N-KP group with a hazard ratio (HR) of 0.2 (P = 0.02). The risks of biliary and vascular complications and cytomegalovirus (CMV) infection after LT were significantly higher in KP-EF group than those in the KP-MF and KP-LF groups (HRs = 0.09, 0.2, and 0.3, respectively; all P < 0.001). The KP significantly improved after LT overall survival. Patients with early native liver failure after KP have significantly higher risks for biliary and vascular complications and CMV infection.

The Effect of Priority Given to Donor Card Holders on the Allocation of Livers for Transplant-Evidence From 7 Years of the Israeli Priority Program

BACKGROUND

The Israeli Transplant Law grants priority in organ allocation to patients signing a donor card. Liver transplant candidates get additional 2 points on their Model for End Stage Liver Disease score for signing a donor card, 0.1 points for a relative holding a card, and 5 points if a relative donated an organ. We studied the effect of the priority program on waiting list mortality and allocation changes due to priority.

METHODS

Using Israeli Transplant data of 531 adult liver transplant candidates with chronic liver disease listed between 2012 and 2018 we compared waitlist mortality and transplant rate of candidates with and without priority. Then we analyzed liver allocations resulting from additional priority points and followed outcome of patients who were skipped in line.

RESULTS

Of the 519 candidates, 294 did not sign a donor card, 82 signed, 140 had a relative sign, and for 3, a relative donated an organ. The rates of waitlist mortality in these 4 groups were 22.4%, 0%, 21.4%, and 0%, respectively, and the transplant rates were 50%, 59.8%, 49.3%, and 100%, respectively. Of the 30 patients who were skipped because of priority, 24 subsequently underwent transplant, 2 are on the waiting list, and 4 died within 0.75, 1.75, 7, and 17 mo.

CONCLUSIONS

The 2 points added to the Model for End Stage Liver Disease score were associated with lower waitlist mortality and higher transplant rate for candidates signing a donor card without significantly affecting access to transplant during allocation. Further research and consideration of optimal policy when granting priority for candidates signing a donor card should continue.

Comparison of thermal variations in post-retrieval graft conditioning on rat livers

BACKGROUND

Machine perfusion was found an effective tool to recover organ grafts from ischemic insults during preservation. It could be observed that organ integrity is significantly affected by abrupt temperature shifts during hypothermic storage and implantation periods. Studies showed that a gentle and controlled rise of the temperature during oxygenated machine perfusion prior to implantation can protect the tissue from reperfusion injury. Now, the possible role of temperature kinetics upon retrieval of the graft and prior to later cold storage should be investigated.

METHODS

Rat livers were retrieved after cardiac arrest and subjected to a brief ex situ machine perfusion with either hypothermic resuscitation (HR) at 8°C, near-normothermic resuscitation (NR) at 30°C or progressive resuscitation with lowering the temperature in a controlled fashion from 30°C to 8°C (PR). After cold storage (CS), liver functional parameters were evaluated by an established ex vivo reperfusion system.

RESULTS

NR and PR resulted in significantly lower release of hepatic enzymes and less production of tumor necrosis factor upon reperfusion compared to CS while HR had a far less protective effect. An increase in bile production was only observed in the PR group, which also significantly increased the recovery of tissue adenosine triphosphate, the amount of which was, however, nearly paralleled by the NR protocol.

CONCLUSION

Within the limitations of this model, it seems that normothermic recirculation appears to be a superior approach for the restitution of warm-ischemically injured liver grafts than immediate hypothermic machine perfusion.

Impact of Pretransplantation CT on Liver Donation in Potential Deceased Organ Donors

BACKGROUND

Computed tomography (CT) is routinely used to determine the suitability of potential living donor liver transplants, providing important information about liver size, vascular anatomy, and the presence of other diseases that would preclude it from safe donation. CT is not routinely used, however, when evaluating eligible deceased organ donors after brain death, a group which comprises most orthotopic liver transplants. After the installation of a CT scanner at a local procurement facility, CTs have been performed on potential deceased organ donors and used, in conjunction with other evaluative protocols, to help direct donation decisions and assist in procurement procedures.

STUDY DESIGN

A retrospective analysis of data from 373 cases spanning 5 years was systematically collected and analyzed, including information pertaining to patient's medical histories, biopsy results, operative findings, and CT results.

RESULTS

CT findings directly impacted the directive decision-making process in 29% of cases in this patient cohort, likely an underestimate, and reliably evaluated important factors including variant vascular anatomy and the presence and severity of hepatic steatosis and cirrhosis.

CONCLUSION

Overall, this study suggests that CT has the potential to play a significant role in procurement procedures and the directive decision-making process, thereby improving the efficiency and accuracy by which potential deceased organ donors are evaluated.

Surgical Considerations Regarding Transplantation for the Patient With Acute-on-Chronic Liver Failure

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Building a Utility-based Liver Allocation Model in Preparation for Continuous Distribution

Background.

The current model for end-stage liver disease-based liver allocation system in the United States prioritizes sickest patients first at the expense of long-term graft survival. In a continuous distribution model, a measure of posttransplant survival will also be included. We aimed to use mathematical optimization to match donors and recipients based on quality to examine the potential impact of an allocation system designed to maximize long-term graft survival.

Methods.

Cox proportional hazard models using organ procurement and transplantation network data from 2008 to 2012 were used to place donors and waitlist candidates into 5 groups of increasing risk for graft loss (1—lowest to 5—highest). A mixed integer programming optimization model was then used to generate allocation rules that maximized graft survival at 5 and 8 y.

Results.

Allocation based on mathematical optimization improved 5-y survival by 7.5% (78.2% versus 70.7% in historic cohort) avoiding 2271 graft losses, and 8-y survival by 9% (71.8% versus 62.8%) avoiding 2725 graft losses. Long-term graft survival for recipients within a quality group is highly dependent on donor quality. All candidates in groups 1 and 2 and 43% of group 3 were transplanted, whereas none of the candidates in groups 4 and 5 were transplanted.

Conclusions.

Long-term graft survival can be improved using a model that allocates livers based on both donor and recipient quality, and the interaction between donor and recipient quality is an important predictor of graft survival. Considerations for incorporation into a continuous distribution model are discussed.

A Clinical Tool to Guide Selection and Utilization of Marginal Donor Livers With Graft Steatosis in Liver Transplantation

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Background.

Donor liver biopsy (DLBx) in liver transplantation provides information on allograft quality; however, predicting outcomes from these allografts remains difficult.

Methods.

Between 2006 and 2015, 16 691 transplants with DLBx were identified from the Standard Transplant Analysis and Research database. Cox proportional hazard regression analyses identified donor and recipient characteristics associated with 30-d, 90-d, 1-y, and 3-y graft survival. A composite model, the Liver Transplant After Biopsy (LTAB) score, was created. The Mini-LTAB was then derived consisting of only donor age, macrosteatosis on DLBx, recipient model for end-stage liver disease score, and cold ischemic time. Risk groups were identified for each score and graft survival was evaluated. P values <0.05 were considered significant.

Results.

The LTAB model used 14 variables and 5 risk groups and identified low-, mild-, moderate-, high-, and severe-risk groups. Compared with moderate-risk recipients, severe-risk recipients had increased risk of graft loss at 30 d (hazard ratio, 3.270; 95% confidence interval, 2.568-4.120) and at 1 y (2.258; 1.928-2.544). The Mini-LTAB model identified low-, moderate-, and high-risk groups. Graft survival in Mini-LTAB high-risk transplants was significantly lower than moderate- or low-risk transplants at all time points.

Conclusions.

The LTAB and Mini-LTAB scores represent guiding principles and provide clinically useful tools for the successful selection and utilization of marginal allografts in liver transplantation.

Postreperfusion syndrome in liver transplantation: Outcomes, predictors, and application for recipient selection

BACKGROUND

This study aimed to identify risk factors for postreperfusion syndrome (PRS) and its impact on LT outcomes.

METHODS

Data analysis was performed in 1021 adult patients undergoing donation after brain death (DBD) LT to identify PRS incidence, the risk factors for PRS development, and its impact on LT outcomes.

RESULTS

The overall incidence of PRS was 16.1%. Independent risk factors for PRS included donor age (odds ratio (OR) 1.01, p = 0.02), donor body mass index (BMI) (OR 1.04, p = 0.003), moderate macrosteatosis (OR 2.48, p = 0.02), and cold ischemia time (CIT) (OR 1.06, p = 0.02). On multivariable analysis for 30-day graft failure, PRS (hazard ratio (HR) 3.49; p<0.001) and Model for End-stage Liver Disease (MELD) score (HR 1.01; p = 0.05) were independent risk factors. Patients were categorized into 4 distinct groups based on PRS risk groups and MELD groups, which showed different 1-year graft survival (p<0.001). There were comparable outcomes between low PRS risk - high MELD and high PRS risk - low MELD group (p = 0.33).

CONCLUSIONS

donor age, donor BMI, moderate macrosteatosis, and CIT were identified as risk factors for the development of PRS in LT using DBD grafts. PRS risk evaluation may improve donor-to-recipient matching based on their MELD scores. This article is protected by copyright. All rights reserved.

Impact of Portable Normothermic Blood-Based Machine Perfusion on Outcomes of Liver Transplant: The OCS Liver PROTECT Randomized Clinical Trial

Question

Can oxygenated portable normothermic perfusion of deceased donor livers for transplant improve outcomes compared with the current standard of care using ischemic cold storage?

Findings

In this multicenter randomized clinical trial of 300 recipients of liver transplants with the donor liver preserved by either normothermic perfusion or conventional ischemic cold storage, normothermic machine perfusion resulted in decreased early liver graft injury and ischemic biliary complications and greater organ utilization.

Meaning

In this study, portable normothermic oxygenated machine perfusion of donor liver grafts resulted in improved outcomes after liver transplant and in more livers being transplanted.

Importance

Ischemic cold storage (ICS) of livers for transplant is associated with serious posttransplant complications and underuse of liver allografts.

Objective

To determine whether portable normothermic machine perfusion preservation of livers obtained from deceased donors using the Organ Care System (OCS) Liver ameliorates early allograft dysfunction (EAD) and ischemic biliary complications (IBCs).

Design, Setting, and Participants

This multicenter randomized clinical trial (International Randomized Trial to Evaluate the Effectiveness of the Portable Organ Care System Liver for Preserving and Assessing Donor Livers for Transplantation) was conducted between November 2016 and October 2019 at 20 US liver transplant programs. The trial compared outcomes for 300 recipients of livers preserved using either OCS (n = 153) or ICS (n = 147). Participants were actively listed for liver transplant on the United Network of Organ Sharing national waiting list.

Interventions

Transplants were performed for recipients randomly assigned to receive donor livers preserved by either conventional ICS or the OCS Liver initiated at the donor hospital.

Main Outcomes and Measures

The primary effectiveness end point was incidence of EAD. Secondary end points included OCS Liver ex vivo assessment capability of donor allografts, extent of reperfusion syndrome, incidence of IBC at 6 and 12 months, and overall recipient survival after transplant. The primary safety end point was the number of liver graft–related severe adverse events within 30 days after transplant.

Results

Of 293 patients in the per-protocol population, the primary analysis population for effectiveness, 151 were in the OCS Liver group (mean [SD] age, 57.1 [10.3] years; 102 [67%] men), and 142 were in the ICS group (mean SD age, 58.6 [10.0] years; 100 [68%] men). The primary effectiveness end point was met by a significant decrease in EAD (27 of 150 [18%] vs 44 of 141 [31%]; P = .01). The OCS Liver preserved livers had significant reduction in histopathologic evidence of ischemia-reperfusion injury after reperfusion (eg, less moderate to severe lobular inflammation: 9 of 150 [6%] for OCS Liver vs 18 of 141 [13%] for ICS; P = .004). The OCS Liver resulted in significantly higher use of livers from donors after cardiac death (28 of 55 [51%] for the OCS Liver vs 13 of 51 [26%] for ICS; P = .007). The OCS Liver was also associated with significant reduction in incidence of IBC 6 months (1.3% vs 8.5%; P = .02) and 12 months (2.6% vs 9.9%; P = .02) after transplant.

Conclusions and Relevance

This multicenter randomized clinical trial provides the first indication, to our knowledge, that normothermic machine perfusion preservation of deceased donor livers reduces both posttransplant EAD and IBC. Use of the OCS Liver also resulted in increased use of livers from donors after cardiac death. Together these findings indicate that OCS Liver preservation is associated with superior posttransplant outcomes and increased donor liver use.

Trial Registration

ClinicalTrials.gov Identifier: NCT02522871

Risk factors of early liver dysfunction after liver transplantation using grafts from donation after citizen death donors

BACKGROUND

As an early complication after liver transplantation, early allograft dysfunction (EAD) indicates a poor prognosis. This study analyzes the risk factors related to early allograft dysfunction (EAD) after liver transplantation using grafts from donation after citizen death (DCD) to provide a reference for the prevention of EAD after DCD liver transplantation.

METHODS

A total of 32 patients who underwent DCD liver transplantation in the organ transplantation center of our hospital from September 2013 to January 2021 were enrolled in this study. The patients were divided into the EAD group and non-EAD group according to whether they developed EAD after transplantation. The general data of the donors and recipients before transplantation, intraoperative conditions, and clinical data within one week after transplantation were compared between the two groups, and related complications were statistically analyzed. The follow-up time was one week postoperatively or, if they died within the first week postoperatively, until the patient died.

RESULTS

The subjects included 10 females and 22 males, and the incidence of postoperative EAD was 25% (8/32). Four patients (12%) had primary malignant tumors (primary liver cancer and cholangiocarcinoma), and five donors (15%) had fatty liver. The univariate analysis revealed that the donor BMI (P = 0.005), degree of fatty liver (P = 0.025), aspartate aminotransferase (P = 0.001), alanine aminotransferase (P < 0.001), and total bilirubin (P = 0.009) were related to the occurrence of EAD after DCD liver transplantation. By analyzing the correlation between the incidence EAD and postoperative complications after liver transplantation using grafts from DCD donors, it was shown that the incidence of primary nonfunction (PNF) is related to EAD (P = 0.024).

CONCLUSION

Donor BMI, the degree of fatty liver, and preoperative liver function are risk factors for EAD after DCD liver transplantation, and the occurrence of EAD after DCD liver transplantation significantly increases the probability of PNF.

Liver Transplantation for Hepatitis D Virus in the United States: A UNOS Study on Outcomes in the MELD Era

BACKGROUND

Without available curative therapies for delta hepatitis (hepatitis delta virus [HDV]), hepatic decompensation and hepatocellular carcinoma (HCC) among HDV patients often necessitates liver transplantation (LT). The objective of this study was to evaluate outcomes of LT among hepatitis B virus (HBV)/HDV patients in the United States.

METHODS

We performed the first US-based retrospective study of patients who underwent LT for HDV compared with HBV (monoinfection) in the years 2002-2019. We evaluated posttransplant survival and predictors of survival.

RESULTS

We identified a total of 152 HBV/HDV and 5435 HBV patients who underwent LT. HDV patients were younger at transplant (52 versus 55, P < 0.001), less commonly Asian (16% versus 36%, P < 0.001), more likely to be HCV Ab positive (42% versus 28%, P < 0.001), and less likely to be listed for LT with HCC (38% versus 51%, P = 0.001), more likely to have ascites (73% versus 64%, P = 0.019), had worse coagulopathy (mean INR 2.0 versus 1.82, P = 0.04), and were more likely to receive a HCV-positive donor organ (7% versus 3%, P = 0.001). Post-LT overall survival and graft survival were similar between HDV and HBV patients, including among patients with HCC. Older age, HCV coinfection, HCC, and higher model for end-stage liver disease at transplant were associated with higher posttransplant mortality.

CONCLUSIONS

HDV patients were sicker and more likely to be listed for LT for decompensated disease compared with HBV patients. Post-LT survival was similar between HDV and HBV patients, in contrast to prior international studies that suggested worse post-LT survival in HBV patients due to higher rates of HBV reactivation.

Artificial Intelligence in hepatology, liver surgery and transplantation: Emerging applications and frontiers of research

The integration of artificial intelligence (AI) and augmented realities into the medical field is being attempted by various researchers across the globe. As a matter of fact, most of the advanced technologies utilized by medical providers today have been borrowed and extrapolated from other industries. The introduction of AI into the field of hepatology and liver surgery is relatively a recent phenomenon. The purpose of this narrative review is to highlight the different AI concepts which are currently being tried to improve the care of patients with liver diseases. We end with summarizing emerging trends and major challenges in the future development of AI in hepatology and liver surgery.

Prescriptive Analytics Determining Which Patients Undergoing Simultaneous Liver-Kidney Transplant May Benefit From High-Risk Organs

OBJECTIVES

Simultaneous liver-kidney transplant is a treatment option for patients with end-stage liver disease and concomitant irreversible kidney injury. We developed a decision toolto aid transplant programs to advise their candidates for simultaneous liver-kidney transplant on accepting high-risk grafts versus waiting for lower-risk grafts.

MATERIALS AND METHODS

To find the critical decision factors, we used the prescriptive analytic technique of microsimulation.All probabilities used in the simulation model were calculated from Organ Procurement and Transplantation Network data collected from February 27, 2002 to June 30, 2018.

RESULTS

The simulated patient population results revealed, on average, that high-risk candidates for simultaneous liver-kidney transplant who accept highrisk organs have 254.8 ± 225.4 weeks of life compared with 285.6 ± 232.4 weeks if they waited for better organs. However, critical decision factors included the specific organ offer rates within individual transplant programs and the rank of the candidate in each program's waitlist. Thus, for programs with lower organ offer rates or for candidates with a rare blood type, a high-risk simultaneous liver-kidney transplant candidate might accept a high-risk organ for longer survival.

CONCLUSIONS

Our model can be utilized to determine when acceptance of high-risk organs for patients being considered for simultaneous liver-kidney transplant would lead to survival benefit, based on probabilities specific for their program.

Disposal of donor livers in Brazil: how to optimize their utilization rate in transplants?

Objective:

To understand the professionals´ perception of the use of deceased donor liver for transplantation, the reasons to decline them, and propose strategies to increase their use safely.

Methods:

This is a cross-sectional, descriptive qualitative-quantitative study. Professionals working with liver transplantation answered a self-administered, structured, and electronic questionnaire comprising 17 questions distributed into four sessions (demographic factors, perception of use of organs, reasons for disposal, and measures to favor their usage).

Results:

A total of 42 professionals participated in the study. The rate of use of organs was considered low by 71.43% (n=30) of respondents or very low by 19.05% (n=8). Everyone agreed that it was possible to increase it. Thirty-one (73.81%) participants believed the expansion of the population of extended criteria donors affected this index negatively. Donor-related conditions were the most frequent category of reasons for refusing a liver for transplantation, being the findings during organ retrieval the most frequent reason in clinical practice. Enhanced training of intensive care teams in the treatment of donors was the primary measure selected to favor the use of the organs, followed by investment in new technologies to optimize its preservation/evaluate its function before transplantation.

Conclusion:

Implementation of strategies to increase the rate of acceptance of livers is expected. Improvements in donor intensive care and implementation of new preservation technologies should favor the use of the organs.

Reassessment of Relevance and Predictive Value of Parameters Indicating Early Graft Dysfunction in Liver Transplantation: AST Is a Weak, but Bilirubin and INR Strong Predictors of Mortality

Introduction: Early graft dysfunction (EAD) complicates liver transplantation (LT). The aim of this analysis was to discriminate between the weight of each variable as for its predictive value toward patient and graft survival. Methods: We reviewed all LT performed at the Medical University of Innsbruck between 2007 and 2018. EAD was recorded when one of the following criteria was present: (i) aspartate aminotransferase (AST) levels >2,000 IU/L within the first 7 days, (ii) bilirubin levels ≥10mg/dL or (iii) international normalized ratio (INR) ≥1.6 on postoperative day 7. Results: Of 616 LT, 30.7% developed EAD. Patient survival did not differ significantly (P = 0.092; log rank-test = 2.87), graft survival was significantly higher in non-EAD patients (P = 0.008; log rank-test = 7.13). Bilirubin and INR on postoperative day 7 were identified as strong mortality predictors (Bilirubin HR = 1.71 [1.34, 2.16]; INR HR = 2.69 [0.51, 14.31]), in contrast to AST (HR = 0.91 [0.75, 1.10]). Similar results were achieved for graft loss estimation. A comparison with the Model for Early Allograft Function (MEAF) and the Liver Graft Assessment Following Transplantation (L-GrAFT) score identified a superior discrimination potential but lower specificity. Conclusion: Contrarily to AST, bilirubin and INR have strong predictive capacity for patient and graft survival. This fits well with the understanding, that bile duct injury and deprivation of synthetic function rather than hepatocyte injury are key factors in LT.

Marginal allografts in liver transplantation have a limited impact on length of stay

The study of marginal liver transplant outcomes, including post-transplant length of stay (LOS), is necessary for determining the practicality of their use. 50 155 patients who received transplants from 2012 to 2020 were retrospectively analyzed with data from the Scientific Registry of Transplant Recipients database using Kaplan-Meier survival curves and multivariable Cox regression. Six different definitions were used to classify an allograft as being marginal: 90^th percentile Donor Risk Index (DRI) allografts, donation after cardiac death (DCD) donors, national share donors, donors over 70, donors with > 30% macrovesicular steatosis, or 90^th percentile Discard Risk Index donors. 24% (n = 12 124) of subjects received marginal allografts. Average LOS was 15.6 days among those who received standard allografts. Among those who received marginal allografts, LOS was found to be highest in those who received 90^th percentile DRI allografts at 15.6 days, and lowest in those who received DCD allografts at 12.7 days. Apart from fatty livers (95% CI .86-.98), marginal allografts were not associated with a prolonged LOS. We conclude that accounting for experience and recipient matching, transplant centers may be more aggressive in their use of extended criteria donors with limited fear of increasing LOS and its associated costs.

Similar Results in Liver Transplantation From Controlled Donation After Circulatory Death Donors With Normothermic Regional Perfusion and Donation After Brain Death Donors: A Case-Matched Single-Center Study

Although good results have been reported with the use of normothermic regional perfusion (NRP) in controlled donation after circulatory death (cDCD) liver transplantation (LT), there is a lack of evidence to demonstrate similar results to donation after brain death (DBD). We present a single-center retrospective case-matched (1:2) study including 100 NRP cDCD LTs and 200 DBD LTs and a median follow-up of 36 months. Matching was done according to donor age, recipient Model for End-Stage Liver Disease score, and cold ischemia time. The following perioperative results were similar in both groups: alanine transaminase peaks of 909 U/L in the DBD group and 836 U/L in the cDCD group and early allograft disfunction percentages of 21% and 19.2%, respectively. The 1-year and 3-year overall graft survival for cDCD was 99% and 93%, respectively, versus 92% and 87%, respectively, for DBD (P = 0.04). Of note, no cases of primary nonfunction or ischemic-type biliary lesion were observed among the cDCD grafts. Our results confirm that NRP cDCD LT meets the same outcomes as those obtained with DBD LT and provides evidence to support the idea that cDCD donors per se should no longer be considered as "marginal donors" when recovered with NRP.

Elevated levels of circulating mitochondrial DNA predict early allograft dysfunction in patients following liver transplantation

BACKGROUND AND AIM

The role of circulating mitochondrial DNA (cmtDNA) in transplantation remains to be elucidated. cmtDNA may be released into the circulation as a consequence of liver injury; yet recent work also suggests a causative role for cmtDNA leading to hepatocellular injury. We hypothesized that elevated cmtDNA would be associated with adverse events after liver transplantation (LT) and conducted an observational cohort study.

METHODS

Twenty-one patients were enrolled prospectively prior to LT.

RESULTS

Postoperative complications were observed in 47.6% (n = 10). Seven patients (33.3%) had early allograft dysfunction (EAD), and six patients (28.5%) experienced acute cellular rejection within 6 months of LT. cmtDNA levels were significantly elevated in all recipients after LT compared with healthy controls and preoperative samples (1 361 937 copies/mL [IQR 586 781-3 399 687] after LT; 545 531 copies/mL [IQR 238 562-1 381 015] before LT; and 194 562 copies/mL [IQR 182 359-231 515] in healthy controls) and returned to normal levels by 5 days after transplantation. cmtDNA levels were particularly elevated in those who developed EAD in the early postoperative period (P < 0.001). In all patients, there was initially a strong overall positive correlation between cmtDNA and plasma hepatocellular enzyme levels (P < 0.05). However, the patients with EAD demonstrated a second peak in cmtDNA at postoperative day 7, which did not correlate with liver function tests.

CONCLUSIONS

The early release of plasma cmtDNA is strongly associated with hepatocellular damage; however, the late surge in cmtDNA in patients with EAD appeared to be independent of hepatocellular injury as measured by conventional tests.

Early transplantation maximizes survival in severe acute-on-chronic liver failure: Results of a Markov decision process model

Background & Aims

Uncertainties exist surrounding the timing of liver transplantation (LT) among patients with acute-on-chronic liver failure grade 3 (ACLF-3), regarding whether to accept a marginal quality donor organ to allow for earlier LT or wait for either an optimal organ offer or improvement in the number of organ failures, in order to increase post-LT survival.

Methods

We created a Markov decision process model to determine the optimal timing of LT among patients with ACLF-3 within 7 days of listing, to maximize overall 1-year survival probability.

Results

We analyzed 6 groups of candidates with ACLF-3: patients age ≤60 or >60 years, patients with 3 organ failures alone or 4-6 organ failures, and hepatic or extrahepatic ACLF-3. Among all groups, LT yielded significantly greater overall survival probability vs. remaining on the waiting list for even 1 additional day (p <0.001), regardless of organ quality. Creation of 2-way sensitivity analyses, with variation in the probability of receiving an optimal organ and expected post-transplant mortality, indicated that overall survival is maximized by earlier LT, particularly among candidates >60 years old or with 4-6 organ failures. The probability of improvement from ACLF-3 to ACLF-2 does not influence these recommendations, as the likelihood of organ recovery was less than 10%.

Conclusion

During the first week after listing for patients with ACLF-3, earlier LT in general is favored over waiting for an optimal quality donor organ or for recovery of organ failures, with the understanding that the analysis is limited to consideration of only these 3 variables.

Lay summary

In the setting of grade 3 acute-on-chronic liver failure (ACLF-3), questions remain regarding the timing of transplantation in terms of whether to proceed with liver transplantation with a marginal donor organ or to wait for an optimal liver, and whether to transplant a patient with ACLF-3 or wait until improvement to ACLF-2. In this study, we used a Markov decision process model to demonstrate that earlier transplantation of patients listed with ACLF-3 maximizes overall survival, as opposed to waiting for an optimal donor organ or for improvement in the number of organ failures.

Development of the Eurotransplant Discard Risk Index to Predict Acceptance of Livers for Transplantation: A Retrospective Database Analysis

OBJECTIVES

The utilization of liver allografts could be optimized if nonacceptance is predicted. This study aimed to evaluate the prognostic ability of an updated Discard Risk Index in Eurotransplant.

MATERIALS AND METHODS

Potential deceased donors from January 2010 to December 2015 who had been reported to Eurotransplant were included in our analyses. Liver utilization was defined by transplant status as the primary outcome to evaluate the performance of the Eurotransplant-developed Discard Risk Index.

RESULTS

Of 11670 potential livers, 9565 (81%) were actually transplanted. Donor sex, age, history of diabetes, drug abuse, use of vasopressors, body mass index category, serum sodium, cause of death, donor type, and levels of C-reactive protein, bilirubin, aspartate and alanine aminotransferases, international normalized ratio, and gamma-glutamyltranspeptidase were associated with discard and combined in the Eurotransplant-developed Discard Risk Index. Correlation between the two Discard Risk Indexes was high (r = 0.86), and both achieved high C statistics of 0.72 and 0.75 (P < .001), respectively. Despite strong calibration, discard rates of 0.8% for overall donors and 6% of donors after circulatory death could be predicted with 80% accuracy.

CONCLUSIONS

The Eurotransplant-developed Discard Risk Index showed a high prognostic ability to predict liver utilization in a European setting. The model could therefore be valuable for identifying livers at high risk of not being transplanted in an early stage. These organs might profit the most from modified allocation strategies or advanced preservation techniques.

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.

Predicting recurrence of hepatocellular carcinoma after liver transplantation using a novel model that incorporates tumor and donor-related factors

Evidence suggests that liver graft quality impacts on posttransplant recurrence of hepatocellular carcinoma (HCC). As of today, selection criteria only use variables related to tumor characteristics. Within the Scientific Registry of Transplant Recipients, we identified patients with HCC who underwent liver transplantation between 2004 and 2016 (development cohort, n = 10 887). Based on tumor recurrence rates, we fitted a competing-risk regression incorporating tumor- and donor-related factors, and we developed a prognostic score. Results were validated both internally and externally in the Australia and New Zealand Liver Transplant Registry. Total tumor diameter (subhazard ratio [sub-HR] 1.52 [1.28-1.81]), alpha-feto protein (sub-HR 1.27 [1.23-1.32], recipient male gender (sub-HR 1.43 [1.18-1.74]), elevated donor body mass index (sub-HR 1.26 [1.01-1.58]), and shared graft allocation policy (sub-HR 1.20 [1.01-1.43]) were independently associated with tumor recurrence. We next developed the Darlica score (sub-HR 2.72 [2.41-3.08] P < 0.001) that allows identifying risky combinations between a given donor and a given recipient. Results were validated internally (n = 3 629) and externally in the Australia and New Zealand Liver Transplant Registry (n = 370). The current score is based on variables that are readily available at the time of graft offer. It allows identifying hazardous donor-recipient combinations in terms of risk of tumor recurrence and overall survival.

Prevalence and outcomes of Clostridioides difficile infection in liver transplant recipients

BACKGROUND AND AIM

Data are limited on whether Clostridioides difficile infection (CDI) in the first year after liver transplantation (LT) is associated with increased mortality. In an Australian setting without hypervirulent strain of C. difficile we investigated the prevalence, risk factors, and patient survival associated with CDI in LT.

METHODS

Consecutive patients who underwent deceased-donor LT from 2007 to 2017 were studied retrospectively. Prevalence and long-term outcomes of LT recipients with and without CDI were examined in the entire LT cohort. A case-control study was performed to investigate risk factors associated with CDI.

RESULTS

Six hundred and forty-nine patients underwent LT, of which 32 (4.9%) were diagnosed with CDI within the first 12 months post-LT. There was no difference in patient survival in the overall LT cohort on Kaplan-Meier analysis when stratified by CDI status (log-rank test, p = .08). Furthermore, age was the only predictor of mortality on Cox regression (hazard ratio (HR) 1.06, 95% confidence interval (CI) 1.00-1.13, p = .03). On multivariable logistic regression, rifaximin pre-LT reduced risk (odds ratio (OR) 0.22, 95% CI 0.65-0.74, p = .01) whereas antibiotics pre-LT (OR 7.02, 95% CI 1.26-39.01, p = .03) and length of hospital stay after LT (OR 1.03, 95% CI 1.01-1.06, p = .02) were associated with increased risk of CDI.

CONCLUSIONS

Within the local setting of our study, CDI within 12 months post-LT is of low severity, associated with pre-LT antibiotic exposure and longer hospital stay but no survival impact after LT. Rifaximin use pre-LT reduced the risk of CDI post-LT.

Transarterial chemoembolization of hepatocellular carcinoma before liver transplantation and risk of post-transplant vascular complications: a multicentre observational cohort and propensity score-matched analysis

BACKGROUND

Transarterial chemoembolization (TACE) in patients with hepatocellular cancer (HCC) on the waiting list for liver transplantation may be associated with an increased risk for hepatic artery complications. The present study aims to assess the risk for, primarily, intraoperative technical hepatic artery problems and, secondarily, postoperative hepatic artery complications encountered in patients who received TACE before liver transplantation.

METHODS

Available data from HCC liver transplantation recipients across six European centres from January 2007 to December 2018 were analysed in a 1 : 1 propensity score-matched cohort (TACE versus no TACE). Incidences of intraoperative hepatic artery interventions and postoperative hepatic artery complications were compared.

RESULTS

Data on postoperative hepatic artery complications were available in all 876 patients (425 patients with TACE and 451 patients without TACE). Fifty-eight (6.6 per cent) patients experienced postoperative hepatic artery complications. In total 253 patients who had undergone TACE could be matched to controls. In the matched cohort TACE was not associated with a composite of hepatic artery complications (OR 1.73, 95 per cent c.i. 0.82 to 3.63, P = 0.149). Data on intraoperative hepatic artery interventions were available in 825 patients (422 patients with TACE and 403 without TACE). Intraoperative hepatic artery interventions were necessary in 69 (8.4 per cent) patients. In the matched cohort TACE was not associated with an increased incidence of intraoperative hepatic artery interventions (OR 0.94, 95 per cent c.i. 0.49 to 1.83, P = 0.870).

CONCLUSION

In otherwise matched patients with HCC intended for liver transplantation, TACE treatment before transplantation was not associated with higher risk of technical vascular issues or hepatic artery complications.

Machine Perfusion in Liver Transplantation: A Systematic Review and Meta-Analysis

Background

Liver transplantation (LTx) is the only treatment option for patients with end-stage liver disease. Novel organ preservation techniques such as hypothermic machine perfusion (HMP) or normothermic machine perfusion (NMP) are under investigation in order to improve organ quality from extended criteria donors and donors after circulatory death. The aim of this study was to systematically review the literature reporting LTx outcomes using NMP or HMP compared to static cold storage (SCS).

Methods

The following data were retrieved: graft primary nonfunction rate, early allograft dysfunction (EAD) rate, biliary complication rate, and 12-month graft and patient survival. A total of 15 studies were included (6 NMP and 9 HMP studies), and meta-analysis was performed only for HMP studies because NMP had considerable differences.

Results

The systematic review showed the potential of NMP to reduce graft injury and lower the liver graft discard rate. The performed quantitative analyses showed that the use of HMP reduces the rate of EAD (odds ratio [OR] 0.51; 95% confidence interval [CI] 0.34–0.76; p = 0.001; I² = 0%) and non-anastomotic biliary strictures (OR 0.34; 95% CI 0.17–0.67; p = 0.002; I² = 0%) compared to SCS.

Conclusion

Our systematic review and meta-analysis revealed that the use of HMP reduces the rate of EAD and non-anastomotic biliary strictures compared to SCS.

Donor Hepatic Occult Collagen Deposition Predisposes to Peritransplant Stress and Impacts Human Liver Transplantation

BACKGROUND AND AIMS

Environmentally triggered chronic liver inflammation can cause collagen deposits, whereas early stages of fibrosis without any specific symptoms could hardly be detectable. We hypothesized that some of the human donor grafts in clinical liver transplantation (LT) might possess unrecognizable fibrosis, affecting their susceptibility to LT-induced stress and hepatocellular damage. This retrospective study aimed to assess the impact of occult hepatic fibrosis on clinical LT outcomes.

APPROACH AND RESULTS

Human (194) donor liver biopsies were stained for collagen with Sirius red, and positive areas (Sirius red-positive area; SRA) were measured. The body mass index, aspartate aminotransferase/alanine aminotransferase ratio, diabetes score was calculated using 962 cases of the donor data at the procurement. LT outcomes, including ischemia-reperfusion injury (IRI), early allograft dysfunction (EAD), and survival rates, were analyzed according to SRA and BARD scores. With the median SRA in 194 grafts of 9.4%, grafts were classified into low-SRA (<15%; n = 140) and high-SRA (≥15%; n = 54) groups. Grafts with high SRA suffered from higher rates of IRI and EAD (P < 0.05) as compared to those with low SRA. Interestingly, high SRA was identified as an independent risk factor for EAD and positively correlated with the donor BARD score. When comparing low-BARD (n = 692) with high-BARD (n = 270) grafts in the same period, those with high BARD showed significantly higher post-LT transaminase levels and higher rates of IRI and EAD.

CONCLUSIONS

These findings from the largest clinical study cohort to date document the essential role of occult collagen deposition in donor livers on LT outcomes. High-SRA and donor BARD scores correlated with an increased incidence of hepatic IRI and EAD in LT recipients. This study provides the rationale for in-depth and prospective assessment of occult fibrosis for refined personalized LT management.

Serum Glycomics on Postoperative Day 7 Are Associated With Graft Loss Within 3 Months After Liver Transplantation Regardless of Early Allograft Dysfunction

BACKGROUND

Prediction of outcome after liver transplantation (LT) is limited by the lack of robust predictors of graft failure. In this prospective study, we aimed to define a serum glycomic signature in the first week after LT that is associated with graft loss at 3 mo after LT.

METHODS

Patients were included between January 1, 2011, and February 28, 2017. Glycomic analysis was performed using DNA sequencer-associated fluorophore-associated capillary electrophoresis on a serum sample 1 wk after LT. Making use of Lasso regression, an optimal glycomic signature was identified associated with 3-mo graft survival.

RESULTS

In this cohort of 131 patients, graft loss at 3 mo occurred in 14 patients (11.9%). The optimal mode, called the GlycoTransplantTest, yielded an area under the curve of 0.95 for association with graft loss at 3 mo. Using an optimized cutoff for this biomarker, sensitivity was 86% and specificity 89%. Negative predictive value was 98%. Odds ratio for graft loss at 3 mo was 70.211 (P < 0.001; 95% confidence interval, 10.876-453.231).

CONCLUSIONS

A serum glycomic signature is highly associated with graft loss at 3 mo. It could support decision making in early retransplantation.

Sex-based Disparities in Hepatocellular Carcinoma Recurrence After Liver Transplantation

BACKGROUND

Women with chronic liver disease have lower rates of hepatocellular carcinoma (HCC) as compared to men; it is unknown if there are sex-based differences in HCC recurrence postliver transplant.

METHODS

We conducted an analysis of patients who underwent liver transplant for HCC in the United Network for Organ Sharing/Organ Procurement and Transplantation Network from January 1, 2012 through December 31, 2017.

RESULTS

A total of 12 711 patients underwent liver transplant for HCC: 2909 (23%) women and 9802 (73%) men. Women had significantly lower rates of postliver transplant HCC recurrence than men (4.0% versus 5.4%, P = 0.002). A cox-regression analysis for postliver transplant HCC recurrence highlighted that even after accounting for etiology of cirrhosis, alpha-fetoprotein at liver transplant, tumor diameter, tumor pathology, and vascular invasion, female sex was associated with a 25% lower risk of postliver transplant HCC recurrence (95% confidence interval: 0.57-0.99). There were no interactions between female sex and the following variables: age, type of locoregional therapy, alpha-fetoprotein, donor sex, body mass index, or nonalcoholic steatohepatitis etiology (P > 0.05 for each).

CONCLUSIONS

This study demonstrates an independent effect of sex on risk for HCC recurrence postliver transplant. Our data highlight an opportunity to better understand HCC tumor biology by investigating the drivers of this sex-based difference in HCC recurrence.

Assessment of Donor Liver Pathology Predicts Survival After Liver Transplantation: A Retrospective Cohort Study

BACKGROUND

The aims of this study were to investigate the pathologic manifestation of pretransplant biopsy and to provide an accurate assessment method for liver graft of China Donation after Citizen's Death (CDCD).

METHODS

A retrospective analysis was performed based on clinical and biopsy data of 96 CDCD liver transplantations completed between January 2012 and December 2017. The pretransplant pathologic sections were semiquantitatively scored according to Banff Schema recommendations on liver allograft pathology. Graft overall survival (OS) and early allograft dysfunction (EAD) rates were observed.

RESULTS

The histologic analysis of the 96 CDCD liver graft biopsy specimens was summarized, including portal area neutrophilic infiltrate, macrovesicular steatosis, microvesicular steatosis, and hepatocellular swelling. Among these pathologic characteristics, only portal area neutrophilic infiltrate ≥20% was an independent risk factor for graft survival, although it has limited effect on the recipient's short-term prognosis.

CONCLUSIONS

We found that portal area neutrophilic infiltrate ≥20% was an independent risk factors for long-term graft survival. According to this criterion, we can identify liver transplant recipients at risk for poor prognosis and make timely interventions.

Urgent Liver Transplantation from Deceased Donor With a Calcified Hydatid Cyst: A Case Report

Liver transplantation is the final treatment option for end-stage liver disease and acute liver failure, although availability of donor organs is a major limitation. The large gap between the growing list of patients awaiting liver transplantation and the scarcity of donor organs has fueled efforts to maximize the existing donor pool and identify new avenues. We treated a 13-year-old boy who had acute liver failure, due to Wilson's disease, with transplantation of a liver from a deceased liver donor with a calcified hydatid cyst. After 3 years of follow-up, liver function tests remained normal, hydatid cyst serology was negative, and no hydatid cyst or other problems were observed.

Effluent Molecular Analysis Guides Liver Graft Allocation to Clinical Hypothermic Oxygenated Machine Perfusion

Hypothermic-oxygenated-machine-perfusion (HOPE) allows assessment/reconditioning of livers procured from high-risk donors before transplantation. Graft referral to HOPE mostly depends on surgeons' subjective judgment, as objective criteria are still insufficient. We investigated whether analysis of effluent fluids collected upon organ flush during static-cold-storage can improve selection criteria for HOPE utilization. Effluents were analyzed to determine cytolysis enzymes, metabolites, inflammation-related mediators, and damage-associated-molecular-patterns. Molecular profiles were assessed by unsupervised cluster analysis. Differences between "machine perfusion (MP)-yes" vs. "MP-no"; "brain-death (DBD) vs. donation-after-circulatory-death (DCD)"; "early-allograft-dysfunction (EAD)-yes" vs. "EAD-no" groups, as well as correlation between effluent variables and transplantation outcome, were investigated. Livers assigned to HOPE (n = 18) showed a different molecular profile relative to grafts transplanted without this procedure (n = 21, p = 0.021). Increases in the inflammatory mediators PTX3 (p = 0.048), CXCL8/IL-8 (p = 0.017), TNF-α (p = 0.038), and ANGPTL4 (p = 0.010) were observed, whereas the anti-inflammatory cytokine IL-10 was reduced (p = 0.007). Peculiar inflammation, cell death, and coagulation signatures were observed in fluids collected from DCD livers compared to those from DBD grafts. AST (p = 0.034), ALT (p = 0.047), and LDH (p = 0.047) were higher in the "EAD-yes" compared to the "EAD-no" group. Cytolysis markers and hyaluronan correlated with recipient creatinine, AST, and ICU stay. The study demonstrates that effluent molecular analysis can provide directions about the use of HOPE.

Machine Learning Prediction of Liver Allograft Utilization From Deceased Organ Donors Using the National Donor Management Goals Registry

Early prediction of whether a liver allograft will be utilized for transplantation may allow better resource deployment during donor management and improve organ allocation. The national donor management goals (DMG) registry contains critical care data collected during donor management. We developed a machine learning model to predict transplantation of a liver graft based on data from the DMG registry.

Methods

Several machine learning classifiers were trained to predict transplantation of a liver graft. We utilized 127 variables available in the DMG dataset. We included data from potential deceased organ donors between April 2012 and January 2019. The outcome was defined as liver recovery for transplantation in the operating room. The prediction was made based on data available 12-18 h after the time of authorization for transplantation. The data were randomly separated into training (60%), validation (20%), and test sets (20%). We compared the performance of our models to the Liver Discard Risk Index.

Results

Of 13 629 donors in the dataset, 9255 (68%) livers were recovered and transplanted, 1519 recovered but used for research or discarded, 2855 were not recovered. The optimized gradient boosting machine classifier achieved an area under the curve of the receiver operator characteristic of 0.84 on the test set, outperforming all other classifiers.

Conclusions

This model predicts successful liver recovery for transplantation in the operating room, using data available early during donor management. It performs favorably when compared to existing models. It may provide real-time decision support during organ donor management and transplant logistics.

Ischemic postconditioning improves the outcome of organs from donors after cardiac death in a pig liver transplantation model and provides synergistic protection with hypothermic machine perfusion

AIM

This study investigated whether ischemic postconditioning (IPO) improved the outcome of organs from donors after cardiac death and had a synergistic effect with hypothermic machine perfusion (HMP) in a pig liver transplantation model.

METHODS

A donor after cardiac death (DCD) model was developed in 48 healthy Bama miniature pigs randomly divided into four groups: simple cold storage group (SCS group), IPO group, HMP group, HMP-IPO group. The levels of serum alanine aminotransferase (ALT), total bilirubin, histopathological findings, apoptotic activity of hepatocytes, international normalized ratio (INR), tumor necrosis factor-α (TNF-α), and Malondialdehyde (MDA) were compared.

RESULTS

All recipients in the SCS group died within 6 h after transplantation. The livers of the recipients in the IPO had 50% survival on day 5. HMP allowed 83.3% survival and HMP-IPO allowed 100% survival. After reperfusion, the recipients in the IPO and HMP-IPO group had lower ALT and total bilirubin levels, less Suzuki score, less apoptosis, and less injury to hepatocytes and biliary ducts and attenuated inflammatory response and oxidative load.

CONCLUSIONS

IPO improved the outcome of organs from donors after cardiac death and had a synergistic effect with HMP in the pig liver transplantation model.

A review of split liver transplantation with full right/left hemi-liver grafts for 2 adult recipients

Liver transplantation has become a routine operation in many transplantation centers worldwide. However, liver graft availability fails to meet patient demands. Split liver transplantation (SPLT), which divides a deceased donor liver into 2 partial liver grafts, is a promising strategy for increasing graft availability for transplantation and ameliorating organ shortage to a certain degree. However, the transplantation community has not yet reached a consensus on SPLT because of the variable results. Specifically, SPLT for 2 adult recipients using full right/left hemi-liver grafts is clinically more challenging in terms of surgical technique and potential postoperative complications. Therefore, this review summarizes the current status of SPLT, focusing on the transplantation of adult recipients. Furthermore, the initiation of the SPLT program, donor allocation, surgical aspects, recipient outcomes, and obstacles to developing this procedure will be thoroughly discussed. This information might help provide an optimal strategy for implementing SPLT for 2 adult recipients among current transplantation societies. Meanwhile, potential obstacles to SPLT might be overcome in the near future with growing knowledge, experience, and refinement of surgical techniques. Ultimately, the widespread diffusion of SPLT may increase graft availability and mitigate organ donation shortages.

Contemporary strategies to assess and manage liver donor steatosis: a review

PURPOSE OF REVIEW

Due to a persistent shortage of donor livers, attention has turned toward ways of utilizing marginal grafts, particularly those with steatosis, without incurring inferior outcomes. Here we review the evaluation and utilization of steatotic liver allografts, highlight recently published data, and discuss novel methods of graft rehabilitation.

RECENT FINDINGS

Although severe liver allograft (>60%) steatosis has been associated with inferior graft and recipient outcomes, mild (<30%) steatosis has not. There is ongoing debate regarding safe utilization of grafts with moderate (30-60%) steatosis. Presently, no established protocols for evaluating steatosis in donor candidates or utilizing such grafts exist. Liver biopsy is accepted as the gold standard technique, though noninvasive methods have shown promise in accurately predicting steatosis. More recently, machine perfusion has been shown to enhance ex situ liver function and reduce steatosis, emerging as a potential means of optimizing steatotic grafts prior to transplantation.

SUMMARY

Steatotic liver allografts constitute a large proportion of deceased donor organs. Further work is necessary to define safe upper limits for the acceptable degree of steatosis, develop standardized evaluation protocols, and establish utilization guidelines that prioritize safety. Machine perfusion has shown promise in rehabilitating steatotic grafts and offers the possibility of expanding the deceased donor pool.

Pretransplant Hepatitis C Virus Treatment Decreases Access to High-quality Livers

Background

Despite the revolutionary role of direct-acting antivirals for hepatitis C virus (HCV), the treatment timing for liver transplant candidates remains controversial. We hypothesize that deferring treatment until after liver transplantation improves access to a larger and higher-quality donor pool without a detrimental impact on post-liver transplantation outcomes.

Methods

This single-center study includes recipients that underwent deceased-donor liver transplant with HCV as the primary indication January 1, 2014, to December 31, 2018. For recipients that were untreated (n = 87) versus treated (n = 42) pre-LT, we compared post-LT mortality using Cox regression with inverse probability of treatment-weighted data.

Results

Among pre-LT untreated recipients, 95% were willing to accept an HCV+ donor, and 44.8% received a positive HCV antibody and nucleic acid amplification test (NAT) liver. Among pre-LT treated recipients, 5% were willing to accept an HCV+ donor, and 100% received a negative HCV antibody and NAT liver. The median calculated model for end-stage liver disease at transplant was similar between pre-LT untreated (13, IQR = 9-22) and treated recipients (11, IQR = 8-14) (P = 0.1). Pre-LT treated recipients received livers from older (47 y old versus 37, P < 0.01) and higher body mass index donors (30.2 versus 26.6; P = 0.04) and spent longer on the waiting list (319 d 180, P < 0.001). Unadjusted post-LT mortality at 1 year was higher in the pre-LT treated recipients (14.6% versus 3.5%, P = 0.02). After adjusting for recipient factors, pre-LT treated recipients trended toward a 3.9 times higher risk of mortality compared with the pre-LT untreated recipients (adjusted hazard ratio = _0.973.86_15.4) (P = 0.06).

Conclusions

Deferring HCV treatment improves access to higher-quality donors and may improve post-LT survival.

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.

Association of Donor and Recipient Cytomegalovirus Serostatus on Graft and Patient Survival in Liver Transplant Recipients

Among solid organ transplant recipients, donor cytomegalovirus (CMV) seropositive (D+) and recipient seronegative (R-) status are associated with an increased risk of graft loss and mortality after kidney or lung transplantation. Whether a similar relationship exists among liver transplant recipients (LTR) is unknown. We assessed graft loss and mortality among adult LTRs from January 1, 2010, to March 14, 2020, in the Organ Procurement and Transplantation Network database. We used multivariable mixed Cox proportional hazards regression to analyze the association of donor and recipient CMV serostatus group with graft loss and mortality, with donor seronegative (D-) and recipient seronegative (R-) as the reference group. Among 54,078 LTRs, the proportion of D-R-, D- and recipient seropositive (R+), D+R-, and D+R+ was 13.4%, 22.5%, 22%, and 42%, respectively. By unadjusted Kaplan-Meier survival curve estimates, survival by the end of follow-up was 73.3%, 73.5%, 70.1%, and 69.7%, among the D-R-, D-R+, D+R-, and D+R+ groups, respectively. By multivariable Cox regression, the CMV D+R- serogroup, but not other serogroups, was independently associated with increased risks of graft loss (adjusted hazard ratio [aHR], 1.13; 95% confidence interval [CI], 1.05-1.22) and mortality (aHR, 1.13; 95% CI, 1.05-1.22). The magnitude of the association of the CMV D+R- serostatus group with mortality was similar when the Cox regression analysis was restricted to the first year after transplant and beyond the first year after transplant: aHR, 1.13 (95% CI, 1.01-1.27) and aHR, 1.13 (95% CI, 1.02-1.25), respectively. Even in an era of CMV preventive strategies, CMV D+R- serogroup status remains independently associated with increased graft loss and mortality in adult LTRs. Factors in addition to direct CMV-associated short-term mortality are likely, and studies to define the underlying mechanism(s) are warranted.