The donor risk index: A decade of experience

Performance of risk prediction models for post-liver transplant patient and graft survival over time

Given liver transplantation organ scarcity, selection of recipients and donors to maximize post-transplant benefit is paramount. Several scores predict post-transplant outcomes by isolating elements of donor and recipient risk, including the donor risk index, Balance of Risk, pre-allocation score to predict survival outcomes following liver transplantation/survival outcomes following liver transplantation (SOFT), improved donor-to-recipient allocation score for deceased donors only/improved donor-to-recipient allocation score for both deceased and living donors (ID2EAL-D/-DR), and survival benefit (SB) models. No studies have examined the performance of these models over time, which is critical in an ever-evolving transplant landscape. This was a retrospective cohort study of liver transplantation events in the UNOS database from 2002 to 2021. We used Cox regression to evaluate model discrimination (Harrell's C) and calibration (testing of calibration curves) for post-transplant patient and graft survival at specified post-transplant timepoints. Sub-analyses were performed in the modern transplant era (post-2014) and for key donor-recipient characteristics. A total of 112,357 transplants were included. The SB and SOFT scores had the highest discrimination for short-term patient and graft survival, including in the modern transplant era, where only the SB model had good discrimination (C ≥ 0.60) for all patient and graft outcome timepoints. However, these models had evidence of poor calibration at 3- and 5-year patient survival timepoints. The ID2EAL-DR score had lower discrimination but adequate calibration at all patient survival timepoints. In stratified analyses, SB and SOFT scores performed better in younger (< 40 y) and higher Model for End-Stage Liver Disease (≥ 25) patients. All prediction scores had declining discrimination over time, and scores relying on donor factors alone had poor performance. Although the SB and SOFT scores had the best overall performance, all models demonstrated declining performance over time. This underscores the importance of periodically updating and/or developing new prediction models to reflect the evolving transplant field. Scores relying on donor factors alone do not meaningfully inform post-transplant risk.

Reappraisal of Donor Age in Liver Transplantation: NASH as a Potential Target to Safely Utilize Old Liver Grafts

BACKGROUND

With the chronic shortage of donated organs, expanding the indications for liver transplantation (LT) from older donors is critical. Nonalcoholic steatohepatitis (NASH) stands out because of its unique systemic pathogenesis and high recurrence rate, both of which might make donor selection less decisive. The present study aims to investigate the usefulness of old donors in LT for NASH patients.

METHODS

The retrospective cohort study was conducted using the Scientific Registry Transplant Recipient database. The cohort was divided into 3 categories according to donor age: young (aged 16-35), middle-aged (36-59), and old donors (60-). Multivariable and Kaplan-Meier analyses were performed to compare the risk of donor age on graft survival (GS).

RESULTS

A total of 67 973 primary adult donation-after-brain-death LTs (2002-2016) were eligible for analysis. The multivariable analysis showed a reduced impact of donor age on GS for the NASH cohort (adjusted hazard ratio = 1.13, 95% confidence interval, 1.00-1.27), comparing old to middle-aged donors. If the cohort was limited to NASH recipients plus 1 of the following, recipient age ≥60, body mass index <30, or Model of End Stage Liver Disease score <30, adjusted hazard ratios were even smaller (0.99 [0.84-1.15], 0.92 [0.75-1.13], or 1.04 [0.91-1.19], respectively). Kaplan-Meier analysis revealed no significant differences in overall GS between old- and middle-aged donors in these subgroups ( P = 0.86, 0.28, and 0.11, respectively).

CONCLUSIONS

Donor age was less influential for overall GS in NASH cohort. Remarkably, old donors were equivalent to middle-aged donors in subgroups of recipient age ≥60, recipient body mass index <30, or Model of End Stage Liver Disease score <30.

A narrative review: predicting liver transplant graft survival using artificial intelligence modeling

Liver transplantation is the only treatment for patients with liver failure. As demand for liver transplantation grows, it remains a challenge to predict the short- and long-term survival of the liver graft. Recently, artificial intelligence models have been used to evaluate the short- and long-term survival of the liver transplant. To make the models more accurate, suitable liver transplantation characteristics must be used as input to train them. In this narrative review, we reviewed studies concerning liver transplantations published in the PubMed, Web of Science, and Cochrane databases between 2017 and 2022. We picked out 17 studies using our selection criteria and analyzed them, evaluating which medical characteristics were used as input for creation of artificial intelligence models. In eight studies, models estimating only short-term liver graft survival were created, while in five of the studies, models for the prediction of only long-term liver graft survival were built. In four of the studies, artificial intelligence algorithms evaluating both the short- and long-term liver graft survival were created. Medical characteristics that were used as input in reviewed studies and had the biggest impact on the accuracy of the model were the recipient's age, recipient's body mass index, creatinine levels in the recipient's serum, recipient's international normalized ratio, diabetes mellitus, and recipient's model of end-stage liver disease score. To conclude, in order to define important liver transplantation characteristics that could be used as an input for artificial intelligence algorithms when predicting liver graft survival, more models need to be created and analyzed, in order to fully support the results of this review.

Characterization of Perioperative Serotonin in Patients Undergoing Orthotopic Liver Transplantation

Background: Platelets were shown to be relevant for liver regeneration. In particular, platelet-stored serotonin (5-HT) proved to be a pro-regenerative factor in this process. The present study aimed to investigate the perioperative course of 5-HT and evaluate associations with patient and graft outcomes after othotopic liver transplantation (OLT). Methods: 5-HT was quantified in plasma and serum of 44 OLT recipients perioperatively, and in their respective donors. Olthoff's criteria for early allograft dysfunction (EAD) were used to evaluate postoperative outcomes. Results: Patients with higher donor intra-platelet 5-HT per platelet (IP 5-HT PP) values had significantly lower postoperative transaminases (ASAT POD1: p = 0.006, ASAT POD5: p = 0.006, ASAT POD10: p = 0.02, ALAT POD1: p = 0.034, ALAT POD5: p = 0.017, ALAT POD10: p = 0.04). No significant differences were seen between postoperative 5-HT values and the occurrence of EAD. A tendency was measured that donor IP 5-HT PP is lower in donor-recipient pairs that developed EAD (p = 0.07). Conclusions: Donor IP 5-HT PP might be linked to the postoperative development of EAD after OLT, as higher donor levels are correlated with a more favorable postoperative course of transaminases. Further studies with larger cohorts are needed to validate these findings.

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.

The Predictive Value of Graft Viability and Bioenergetics Testing Towards the Outcome in Liver Transplantation

Donor organ biomarkers with sufficient predictive value in liver transplantation (LT) are lacking. We herein evaluate liver viability and mitochondrial bioenergetics for their predictive capacity towards the outcome in LT. We enrolled 43 consecutive patients undergoing LT. Liver biopsy samples taken upon arrival after static cold storage were assessed by histology, real-time confocal imaging analysis (RTCA), and high-resolution respirometry (HRR) for mitochondrial respiration of tissue homogenates. Early allograft dysfunction (EAD) served as primary endpoint. HRR data were analysed with a focus on the efficacy of ATP production or P-L control efficiency, calculated as 1-L/P from the capacity of oxidative phosphorylation P and non-phosphorylating respiration L. Twenty-two recipients experienced EAD. Pre-transplant histology was not predictive of EAD. The mean RTCA score was significantly lower in the EAD cohort (-0.75 ± 2.27) compared to the IF cohort (0.70 ± 2.08; p = 0.01), indicating decreased cell viability. P-L control efficiency was predictive of EAD (0.76 ± 0.06 in IF vs. 0.70 ± 0.08 in EAD-livers; p = 0.02) and correlated with the RTCA score. Both RTCA and P-L control efficiency in biopsy samples taken during cold storage have predictive capacity towards the outcome in LT. Therefore, RTCA and HRR should be considered for risk stratification, viability assessment, and bioenergetic testing in liver transplantation.

A contemporary analysis of 20,086 deceased donor liver biopsies

BACKGROUND

Pre-transplant deceased donor liver biopsy may impact decision making; however, interpretation of the results remains variable and depends on accepting center practice patterns.

METHODS

In this cohort study, adult recipients from 04/01/2015-12/31/2020 were identified using the UNOS STARfile data. The deceased donor liver biopsies were stratified by risk based on degree of fibrosis, macrovesicular fat content, and level of portal infiltration (low-risk: no fibrosis, no portal infiltrates, and <30% macrosteatosis; moderate-risk: some fibrosis or mild infiltrates and <30% macrosteatosis; high-risk: most fibrosis, moderate/marked infiltrates, or ≥30% macrosteatosis). Graft utilization, donor risk profile, and recipient outcomes were compared across groups.

RESULTS

Of the 51,094 donor livers available, 20,086 (39.3%) were biopsied, and 34,606 (67.7%) were transplanted. Of the transplanted livers, 14,908 (43.1%) were biopsied. The transplanted grafts had lower mean macrovesicular fat content (9.3% transplanted vs. 26.9% non-transplanted, P < 0.001) and less often had any degree of fibrosis (20.9% vs. 39.9%, P < 0.001) or portal infiltration (51.3% vs. 58.2%, P < 0.001) versus non-transplanted grafts. Post-transplant recipient LOS (14.2 days high-risk vs. 15.2 days low-risk, P = 0.170) and 1-year graft survival (90.5% vs. 91.7%, P = 0.137) did not differ significantly between high- versus low-risk groups. Kaplan-Meier survival estimates further revealed no differences in the 5-year graft survival across risk strata (P = 0.833). Of the 5178 grafts biopsied and turned down, PSM revealed 1338 (26.0%) were potentially useable based on biopsy results and donor characteristics.

CONCLUSION

Carefully matched deceased donor livers with some fibrosis, inflammation, or steatosis ≥30% may be suitable for transplantation. Further study of this group of grafts may decrease turndowns of potentially useable organs.

Ventilator support in the pretransplant period predisposes early graft failure after deceased donor liver transplantation

Purpose

Deceased donor liver transplantation (DDLT) recipients in Korea are generally sicker due to an increasing organ shortage. In the present study, the risk factors for early 30-day liver graft failure after DDLT were identified.

Methods

From August 2017 to February 2021, 265 adult DDLTs were performed. The characteristics of patients with and without 30-day graft failure were compared.

Results

Liver graft failure occurred in 11 patients (17.7%) after DDLT. Baseline and perioperative characteristics of donors and recipients were not statistically significantly different between the 2 groups. The cumulative graft and overall survival rates at 6 months were 83.9% and 88.7%, respectively. Multivariate analysis showed ventilator support in the pretransplant period was a predisposing factor for 30-day graft failure after DDLT.

Conclusion

Present study indicates that cautious decision is required when allocating DDLT in critically ill patients on mechanical ventilatory support.

The Impact of Donor Risk Index, Recipients' and Operative Characteristics on Post Liver Transplant One-Year Graft Failure: A Cohort Analysis

Background and Aims

The donor risk index (DRI) quantifies donor-related characteristics potentially associated with increased risk of early graft failure. We aimed to assess the impact of the DRI, recipient and perioperative factors on post liver transplant (LT) outcomes.

Methods

This was a single-center retrospective cohort study including all adult (≥18 years) patients who underwent LT from 01/2019 to 12/2019 at Curry Cabral Hospital, Lisbon, Portugal. Primary endpoint was 1-year graft failure post LT. Associations were studied with logistic regression.

Results

A total of 131 cadaveric donor LT procedures were performed in 116 recipients. Recipients' median (IQR) age was 57 (47-64) years and 101/131 (77.1%) were males. Cirrhosis was the underlying etiology in 95/131 (81.2%) transplants. Based on 8 predefined donors' characteristics, median (IQR) DRI was 1.96 (1.67-2.16). Following adjustment for MELDNa score pre LT and SOFA score (adjusted odds ratio [aOR], 95% confidence interval [CI] = 0.91 [0.56-1.47]) or lactate (aOR [95% CI] = 2.76 [0.71-10.7]) upon intensive care unit (ICU) admission post LT, DRI was not associated with 1-year graft failure. However, higher SOFA score (aOR [95% CI] = 1.20 [1.05-1.37]) or lactate (aOR [95% CI] = 1.27 [1.10-1.46]) upon ICU admission post LT were independently associated with higher odds of 1-year graft failure.

Conclusions

In a recent cohort of patients who underwent LT, DRI, despite being high, was not associated with 1-year graft failure, but SOFA score or lactate upon ICU admission post LT were.

Transplanting hepatitis B surface antigen-positive livers in the United States: Outcomes and opportunities

Livers from donors with positive hepatitis B surface antigens (HBsAg+) have been used to expand the donor pool; however, outcome data are limited. We aim to evaluate survival following liver transplant (LT) from HBsAg+ donors. Using the United Network for Organ Sharing registry, we identified HBsAg+ donors used for LT from 2009 to 2020. We used Kaplan-Meier survival and Cox proportional hazards regression to compare post-LT survival in hepatitis B virus-negative recipients who utilized HBsAg+ donors to propensity-matched cohorts who utilized other types of donors. From 2009-2020, 70 patients received HBsAg+ livers, and 58 of them did not carry a diagnosis of chronic hepatitis B virus. The 1- and 3-year post-LT survival for hepatitis B virus-negative patients who received livers from HBsAg+ donors were 96.6% and 91.4%, respectively, with no statistical differences compared with patients who received livers from hepatitis C virus viremic donors (96.5%/93.0%, P = .961/.427), donation after cardiac death donors (93.0%/86.0%, P = .651/.598), average-risk donors (89.5%/86.0%, P = 0.264/0.617), and a combination of extended-criteria donors, including donation after cardiac death, donor age over 70, and graft with greater than 30% steatosis (93.0%/91.2%, P = .621/.785). Recipients of HBsAg+ livers have similar post-LT survival compared with those receiving other types of grafts. Increasing the utilization of HBsAg+ livers could safely expand the donor pool.

Perioperative clinical practice in liver transplantation: a cross-sectional survey

PURPOSE

The objective of this study was to describe some components of the perioperative practice in liver transplantation as reported by clinicians.

METHODS

We conducted a cross-sectional clinical practice survey using an online instrument containing questions on selected themes related to the perioperative care of liver transplant recipients. We sent email invitations to Canadian anesthesiologists, Canadian surgeons, and French anesthesiologists specialized in liver transplantation. We used five-point Likert-type scales (from "never" to "always") and numerical or categorical answers. Results are presented as medians or proportions.

RESULTS

We obtained answers from 130 participants (estimated response rate of 71% in Canada and 26% in France). Respondents reported rarely using transesophageal echocardiography routinely but often using it for hemodynamic instability, often using an intraoperative goal-directed hemodynamic management strategy, and never using a phlebotomy (medians from ordinal scales). Fifty-nine percent of respondents reported using a restrictive fluid management strategy to manage hemodynamic instability during the dissection phase. Forty-two percent and 15% of respondents reported using viscoelastic tests to guide intraoperative and postoperative transfusions, respectively. Fifty-four percent of respondents reported not pre-emptively treating preoperative coagulations disturbances, and 91% reported treating them intraoperatively only when bleeding was significant. Most respondents (48-64%) did not have an opinion on the maximal graft ischemic times. Forty-seven percent of respondents reported that a piggyback technique was the preferred vena cava anastomosis approach.

CONCLUSION

Different interventions were reported to be used regarding most components of perioperative care in liver transplantation. Our results suggest that significant equipoise exists on the optimal perioperative management of this population.

Artificial Intelligence Applications in Hepatology

Over the past 2 decades, the field of hepatology has witnessed major developments in diagnostic tools, prognostic models, and treatment options making it one of the most complex medical subspecialties. Through artificial intelligence (AI) and machine learning, computers are now able to learn from complex and diverse clinical datasets to solve real-world medical problems with performance that surpasses that of physicians in certain areas. AI algorithms are currently being implemented in liver imaging, interpretation of liver histopathology, noninvasive tests, prediction models, and more. In this review, we provide a summary of the state of AI in hepatology and discuss current challenges for large-scale implementation including some ethical aspects. We emphasize to the readers that most AI-based algorithms that are discussed in this review are still considered in early development and their utility and impact on patient outcomes still need to be assessed in future large-scale and inclusive studies. Our vision is that the use of AI in hepatology will enhance physician performance, decrease the burden and time spent on documentation, and reestablish the personalized patient-physician relationship that is of utmost importance for obtaining good outcomes.

Radiological-histopathological discordance in patients transplanted for HCC and its impact on post-transplant outcomes

BACKGROUND AND AIMS

Contrast-enhanced cross-sectional imaging is the cornerstone in the diagnosis, staging, and management of HCC, including eligibility for liver transplantation (LT). Radiological-histopathological discordance may lead to improper staging and may impact patient outcomes. We aimed to assess the radiological-histopathological discordance at the time of LT in HCC patients and its impact on the post-LT outcomes.

METHODS

We analyzed further the effect of 6-month waiting policy on the discordance. Using United Network for Organ Sharing-Organ Procurement and Transplantation Network (UNOS-OPTN) database, we examined the discordance between pre-LT imaging and explant histopathology for all adult HCC patients who received liver transplants from deceased donors between April 2012 and December 2017. Kaplan-Meier methods and Cox regression analyses were used to evaluate the impact of discordance on 3-year HCC recurrence and mortality.

RESULTS

Of 6842 patients included in the study, 66.7% were within Milan criteria on both imaging and explant histopathology, and 33.3% were within the Milan based on imaging but extended beyond Milan on explant histopathology. Male gender, increasing numbers of tumors, bilobar distribution, larger tumor size, and increasing AFP are associated with increased discordance. Post-LT HCC recurrence and death were significantly higher in patients who were discordant, with histopathology beyond Milan (adj HR 1.86, 95% CI 1.32-2.63 for mortality and 1.32, 95% CI 1.03-1.70 for recurrence). Graft allocation policy with 6-month waiting time led to increased discordance (OR 1.19, CI 1.01-1.41), although it did not impact post-LT outcome.

CONCLUSION

Current practice for staging of HCC based on radiological imaging features alone results in underestimation of HCC burden in one out of three patients with HCC. This discordance is associated with a higher risk of post-LT HCC recurrence and mortality. These patients will need enhanced surveillance to optimize patient selection and aggressive LRT to reduce post-LT recurrence and increase survival.

Characteristics, Risk Factors, and Outcome of New-onset Systolic Heart Failure After Liver Transplantation: A Single-center Cohort

New-onset systolic heart failure (HF) after liver transplantation (LT) is a significant cause of morbidity and mortality; however, its characteristics are still insufficiently delineated. HF may involve the left ventricle (LV), right ventricle (RV), or both ventricles. We explored the incidence, characteristics, etiologies, risks, involved cardiac chambers, and outcomes of HF after LT.

Methods

This study included 528 adult patients with preoperative LV ejection fraction ≥ 55% who underwent LT between 2016 and 2020. The primary outcome was new-onset systolic HF, defined by the presence of clinical signs, symptoms, and echocardiographic evidence of reduced LVejection fraction <50% and RV dysfunction within the first year after LT.

Results

Thirty-one patients (6%) developed systolic HF within a median of 9 d (1-364). Of those, 23% of patients had ischemic HF, whereas 77% had nonischemic HF. Nonischemic HF was caused by stress (11), sepsis (8), or other factors (5). Nonischemic HF was secondary to isolated LV failure in 58% of patients or RV ± LV failure in 42% of patients. Recursive partitioning identified subgroups with varying risks and uncovered interaction between variables. HF risk increased from 4.2% to 13% when epinephrine and/or norepinephrine drips were used intraoperatively (P < 0.01). When no epinephrine and/or norepinephrine were used, HF risk increased from 3.1% to 38.5% if baseline hemoglobin was <7.2 g/dL (P < 0.01). When baseline hemoglobin was ≥7.2 g/dL, HF risk increased from 0% to 5.2% when ≥3500 mL crystalloid was used intraoperatively (P < 0.01). Posttransplant first-year survival and reversibility of HF depended on the etiology (stress, sepsis, ischemia, etc) and cardiac chamber involvement (isolated LV or RV ± LV). RV dysfunction was associated with inferior recovery of cardiac function and poorer survival than nonischemic isolated LV dysfunction (50% versus 70%, respectively).

Conclusions

Posttransplant new-onset HF is mostly nonischemic in nature and is associated with increased morbidity and mortality.

Assessing Donor Liver Quality and Restoring Graft Function in the Era of Extended Criteria Donors

Liver transplantation (LT) is the final treatment option for patients with end-stage liver disease. The increasing donor shortage results in the wide usage of grafts from extended criteria donors across the world. Using such grafts is associated with the elevated incidences of post-transplant complications including initial nonfunction and ischemic biliary tract diseases, which significantly reduce recipient survival. Although several clinical factors have been demonstrated to impact donor liver quality, accurate, comprehensive, and effective assessment systems to guide decision-making for organ usage, restoration or discard are lacking. In addition, the development of biochemical technologies and bioinformatic analysis in recent years helps us better understand graft injury during the perioperative period and find potential ways to restore graft function. Moreover, such advances reveal the molecular profiles of grafts or perfusate that are susceptible to poor graft function and provide insight into finding novel biomarkers for graft quality assessment. Focusing on donors and grafts, we updated potential biomarkers in donor blood, liver tissue, or perfusates that predict graft quality following LT, and summarized strategies for restoring graft function in the era of extended criteria donors. In this review, we also discuss the advantages and drawbacks of these potential biomarkers and offer suggestions for future research.

The impact of perceived donor liver quality on post-transplant outcome

BACKGROUND

We analysed the impact of perceived liver donor quality on transplant recipient outcomes.

METHODS

this prospective cohort study included all deceased liver donors during 2008-2018 in the Swiss Transplant Cohort Study. Perceived low-quality liver donors were defined when refused for ≥5 top listed recipients or for all recipients in at least one centre before being transplanted. The effect of liver donor quality on relisting or recipient death at 1 week and 1 year after transplantation was analysed using Kaplan-Meier and Cox proportional hazard models. A 1:3 matching was also performed using a recipient score.

RESULTS

Of 973 liver donors, 187 (19.2%) had perceived poor-quality. Males, obesity, donation after circulatory death and alanine aminotransferase values were significantly associated with perceived poor-quality, with no significant effect of the perceived quality on re-listing or death within the first week and first year post-transplant [(aHR) = 1.45, 95% CI: (0.6, 3.5), P = 0.41 and aHR = 1.52 (95% CI 0.98-2.35), P = 0.06], adjusting by recipient age and gender, obesity, diabetes, prior liver transplantation and model for end-stage liver disease (MELD) score. At 1 year, prior liver transplantation and higher MELD score associated with higher risk of re-listing or death.

CONCLUSION

Comparable post-transplant outcomes with different perceived quality liver donors stresses the need to improve donor selection in liver transplantation.

Defining Surgical Difficulty of Liver Transplantation

OBJECTIVE

To define technically Diff-LT.

SUMMARY OF BACKGROUND DATA

Currently, there is no acknowledged definition of Diff-LT.

METHODS

This retrospective study included all first consecutive liver-only transplantations performed in 2 centers from 2011 to 2015. Diff-LT was defined as the combination of the number of blood units transfused, cold ischemia time, and duration of operation, all at or above the median value of the entire population. The correlation of Diff-LT with short- (including the comprehensive complication index) and long-term outcomes was assessed. Outcomes were also compared to the 90-day benchmark cutoffs of LT. Predictors of Diff-LT were identified by multivariable analysis, first using only recipient data and then using all recipient, donor, graft, and surgical data.

RESULTS

The study population included 467 patients. The incidence of Diff- LT was 18.8%. Diff-LT was associated with short-term outcomes, including the comprehensive complication index and mortality, but not with patient or graft long-term survival. Previous abdominal surgery, intensive care unitbound at the time of LT, split graft use, nonstandard arterial reconstruction, and porto-systemic shunt ligation were independent predictors of Diff-LT. The proportion of variables below the corresponding LT 90-day benchmark cutoffs was 8/13 (61.5%) for non-Diff-LT, and 4/13 (30.8%) for Diff-LT.

CONCLUSIONS

Diff-LT, as defined, occurred frequently. Adjusting modifiable variables might decrease the risk of Diff-LT and improve the postoperative course. This definition of Diff-LT might be useful for patient information, comparison between centers and surgeons, and as a metric in future trials.

Liver Transplantation for Budd-Chiari Syndrome in the MELD Era

To evaluate clinical characteristics and factors associated with survival among liver transplantation (LT) recipients with Budd-Chiari syndrome (BCS), with or without transjugular intrahepatic portosystemic shunt (TIPS), in the post-Model for End-stage Liver Disease era.

METHODS

We extracted data from the United Network for Organ Sharing database on all adult (≥18 y old) waitlisted candidates and recipients of LT with BCS in the United States between 2002 and 2019. Multivariable Cox regression was used to determine predictors of mortality and hazard ratios (HRs).

RESULTS

A total of 647 BCS patients were waitlisted between 2002 and 2019. BCS was an indication for LT in 378 (0.2%) of all adult LT recipients during the study period. Of BCS patients who received LT, approximately three-fourths (72.3%) were alive for up to 10 y. We found no significant difference in LT outcomes in BCS patients with or without TIPS. Longer length of hospital stay following LT (HR, 1.32; 95% confidence interval [CI], 1.19-1.47), Black/African American race (HR, 2.24; 95% CI, 1.38-3.64), diabetes (HR, 3.17; 95% CI, 1.62-6.21), donor risk index (HR, 1.44; 95% CI, 1.05-1.99), and lower albumin levels at the time of transplantation (HR, 0.66; 95% CI, 0.50-0.88) were negatively associated with survival after LT. Interestingly, neither the Model for End-stage Liver Disease nor prior TIPS showed a significant association with survival after LT.

CONCLUSIONS

These findings demonstrate good comparable survival among TIPS versus no TIPS in LT recipients with BCS. The decision for TIPS versus LT should be individualized on a case-by-case basis.

New-Onset Atrial Fibrillation in Patients Undergoing Liver Transplantation: Retrospective Analysis of Risk Factors and Outcomes

OBJECTIVE

The authors aimed to identify predictors of new-onset postoperative atrial fibrillation (POAF) during the initial 90 days following liver transplantation, and to assess the association between POAF in-hospital and 1-year mortality.

DESIGN

A retrospective cohort study.

SETTING

At a university hospital between 2005 and 2017.

PATIENTS

Adults without a history of preoperative atrial fibrillation who underwent orthotopicliver transplantation.

MEASUREMENT AND MAIN RESULTS

The authors assessed the univariate association between new-onset of POAF in the postoperative period and each potential factor through a logistic regression model. Moreover, they explored predictors for POAF through stepwise selection. Finally, the authors assessed the relationship between POAF and in-hospital and 1-year mortality using logistic regression models, and whether the duration of atrial fibrillation was associated with in-hospital and 1-year mortality. Among 857 patients, 89 (10.4%) developed POAF. Using only preoperative variables, pulmonary hypertension, age, Model for End-Stage Liver Disease (MELD) score, and White race were identified as the most important predictors. Model discrimination was 0.75 (95% CI: 0.69-0.80), and incorporating intraoperative variables was 0.77 (95% CI: 0.72-0.82). In-hospital mortality was observed in 7.2% (6/83) of patients with new-onset of POAF, and in 2.8% (22/768) without, with confounder-adjusted odds ratio (OR) 1.00 (97.5% CI: 0.29,3.45; p = 0.996). One-year mortality was 22.4% (20/89) in patients who developed POAF and 8.3% (64/768) in patients who did not, confounder-adjusted OR 2.64 (97.5% CI: 1.35-5.16; p = 0.001). The duration of POAF did not affect long-term postoperative mortality.

CONCLUSION

Preoperative, mostly unmodifiable comorbidities are important risk factors for new-onset POAF after liver transplantation. The POAF was not associated with in-hospital mortality, but with increased 1-year mortality. Once developed, the duration of POAF did not affect long-term mortality after a liver transplant.

How useful is the machine perfusion in liver transplantation? An answer from a national survey

Machine perfusion (MP) has been shown worldwide to offer many advantages in liver transplantation, but it still has some gray areas. The purpose of the study is to evaluate the donor risk factors of grafts, perfused with any MP, that might predict an ineffective MP setting and those would trigger post-transplant early allograft dysfunction (EAD). Data from donors of all MP-perfused grafts at six liver transplant centers have been analyzed, whether implanted or discarded after perfusion. The first endpoint was the negative events after perfusion (NegE), which is the number of grafts discarded plus those that were implanted but lost after the transplant. A risk factor analysis for NegE was performed and marginal grafts for MP were identified. Finally, the risk of EAD was analyzed, considering only implanted grafts. From 2015 to September 2019, 158 grafts were perfused with MP: 151 grafts were implanted and 7 were discarded after the MP phase because they did not reach viability criteria. Of 151, 15 grafts were lost after transplant, so the NegE group consisted of 22 donors. In univariate analysis, the donor risk index >1.7, the presence of hypertension in the medical history, static cold ischemia time, and the moderate or severe macrovesicular steatosis were the significant factors for NegE. Multivariate analysis confirmed that macrosteatosis >30% was an independent risk factor for NegE (odd ratio 5.643, p = 0.023, 95% confidence interval, 1.27–24.98). Of 151 transplanted patients, 34% experienced EAD and had worse 1- and 3-year-survival, compared with those who did not face EAD (NoEAD), 96% and 96% for EAD vs. 89% and 71% for NoEAD, respectively (p = 0.03). None of the donor/graft characteristics was associated with EAD even if the graft was moderately steatotic or fibrotic or from an aged donor. For the first time, this study shows that macrovesicular steatosis >30% might be a warning factor involved in the risk of graft loss or a cause of graft discard after the MP treatment. On the other hand, the MP seems to be useful in reducing the donor and graft weight in the development of EAD.

Modelling kidney outcomes based on MELD eras - impact of MELD score in renal endpoints after liver transplantation

Background

Acute kidney injury is a common complication in solid organ transplants, notably liver transplantation. The MELD is a score validated to predict mortality of cirrhotic patients, which is also used for organ allocation, however the influence of this allocation criteria on AKI incidence and mortality after liver transplantation is still uncertain.

Methods

This is a retrospective single center study of a cohort of patients submitted to liver transplant in a tertiary Brazilian hospital: Jan/2002 to Dec/2013, divided in two groups, before and after MELD implementation (pre-MELD and post MELD). We evaluate the differences in AKI based on KDIGO stages and mortality rates between the two groups.

Results

Eight hundred seventy-four patients were included, 408 in pre-MELD and 466 in the post MELD era. The proportion of patients that developed AKI was lower in the post MELD era (p 0.04), although renal replacement therapy requirement was more frequent in this group (p < 0.01). Overall mortality rate at 28, 90 and 365 days was respectively 7%, 11% and 15%. The 1-year mortality rate was lower in the post MELD era (20% vs. 11%, p < 0.01). AKI incidence was 50% lower in the post MELD era even when adjusted for clinically relevant covariates (p < 0.01).

Conclusion

Liver transplants performed in the post MELD era had a lower incidence of AKI, although there were more cases requiring dialysis. 1-year mortality was lower in the post MELD era, suggesting that patient care was improved during this period.

The Impact of Donor and Recipient Genetic Variation on Outcomes After Solid Organ Transplantation: A Scoping Review and Future Perspectives

At the outset of solid organ transplantation, genetic variation between donors and recipients was recognized as a major player in mechanisms such as allograft tolerance and rejection. Genome-wide association studies have been very successful in identifying novel variant-trait associations, but have been difficult to perform in the field of solid organ transplantation due to complex covariates, era effects, and poor statistical power for detecting donor-recipient interactions. To overcome a lack of statistical power, consortia such as the International Genetics and Translational Research in Transplantation Network have been established. Studies have focused on the consequences of genetic dissimilarities between donors and recipients and have reported associations between polymorphisms in candidate genes or their regulatory regions with transplantation outcomes. However, knowledge on the exact influence of genetic variation is limited due to a lack of comprehensive characterization and harmonization of recipients' or donors' phenotypes and validation using an experimental approach. Causal research in genetics has evolved from agnostic discovery in genome-wide association studies to functional annotation and clarification of underlying molecular mechanisms in translational studies. In this overview, we summarize how the recent advances and progresses in the field of genetics and genomics have improved the understanding of outcomes after solid organ transplantation.

Prädiktoren für erfolgreiche Lebertransplantationen und Risikofaktoren

Die Lebertransplantation ist die einzige kurative Therapieoption einer chronischen Leberinsuffizienz im Endstadium. Daneben stellen onkologische Lebererkrankungen wie das HCC eine weitere Indikation für die Lebertransplantation dar, ebenso wie das akute Leberversagen.

Seit der ersten erfolgreichen Lebertransplantation durch Professor Thomas E. Starzl im Jahr 1967 haben sich nicht nur die chirurgischen, immunologischen und anästhesiologischen Techniken und Möglichkeiten geändert, sondern auch die Indikationen und das Patientengut. Hinzu kommt, dass die Empfänger ein zunehmendes Lebensalter und damit einhergehend mehr Begleiterkrankungen aufweisen.

Die Zahl an Lebertransplantationen ist weltweit weiter ansteigend. Es benötigen aber mehr Menschen eine Lebertransplantation, als Organe zur Verfügung stehen. Dies liegt am zunehmenden Bedarf an Spenderorganen bei gleichzeitig weiter rückläufiger Zahl postmortaler Organspenden.

Diese Diskrepanz zwischen Spenderorganen und Empfängern kann nur zu einem kleinen Teil durch Split-Lebertransplantationen oder die Leberlebendspende kompensiert werden.

Um den Spenderpool zu erweitern, werden zunehmend auch marginale Organe, die nur die erweiterten Spenderkriterien („extended donor criteria [EDC]“) erfüllen, allokiert. In manchen Ländern zählen hierzu auch die sogenannten DCD-Organe (DCD: „donation after cardiac death“), d. h. Organe, die erst nach dem kardiozirkulatorischen Tod des Spenders entnommen werden.

Es ist bekannt, dass marginale Spenderorgane mit einem erhöhten Risiko für ein schlechteres Transplantat- und Patientenüberleben nach Lebertransplantation einhergehen.

Um die Qualität marginaler Spenderorgane zu verbessern, hat sich eine rasante Entwicklung der Techniken der Organkonservierung über die letzten Jahre gezeigt. Mit der maschinellen Organperfusion besteht beispielsweise die Möglichkeit, die Organqualität deutlich zu verbessern. Insgesamt haben sich die Risikokonstellationen von Spenderorgan und Transplantatempfänger deutlich geändert.

Aus diesem Grunde ist es von großer Bedeutung, spezifische Prädiktoren für eine erfolgreiche Lebertransplantation sowie die entsprechenden Risikofaktoren für einen schlechten postoperativen Verlauf zu kennen, um das bestmögliche Transplantat- und Patientenüberleben nach Lebertransplantation zu ermöglichen.

Diese Einflussfaktoren, inklusive möglicher Risiko-Scores, sollen hier ebenso wie die neuen technischen Möglichkeiten in der Lebertransplantation beleuchtet werden.

High-risk liver transplant recipients with grade 3 acute on chronic liver failure should receive the good quality graft

BACKGROUND & AIM

We aimed to develop a risk score for LT recipients and donor selection among patients with ACLF-3.

METHODS AND RESULTS

A total of 7166 adult LT recipients (mean age 53 years, 63% males, 56% Caucasians, 42% obese, median MELD score 36.5) using deceased donor grafts in the UNOS database (01/2002-06/2018) who were in ACLF-3 at LT as per EASL-CLIF criteria were analysed. Cox regression model on the derivation dataset (N = 3583) showed recipient age, non-alcohol aetiology, pulmonary failure, brain failure and cardiovascular failure to be associated with 1-year patient survival. Observed and expected post-transplant 1-year survival showed excellent correlation (R = .920). Risk score from cox model on derivation dataset stratified 3583 recipients in validation cohort using cut-off scores 7.55 and 11.57 to low (N = 1211), medium (N = 1168) and high risk (N = 1199), with 1-year patient survival of 89%, 82% and 80% respectively. Based on poor versus good quality graft (donor risk index cut-off at 1.50), 1-year patient survival for low, medium and high-risk categories were 90 versus 89% (p = .490), 83 versus 82% (p = .390) and 83 versus 78% (p = .038) respectively. Among recipients with a high-risk score, donor factors of age ≥60 years, grafts obtained from national sharing and macro-steatosis >15% were associated with 1-year patient survival below 66%.

CONCLUSION

Among ACLF-3 liver transplant recipients, those with high risk at the time of transplant receiving better quality graft will improve post-transplant outcomes. Prospective studies using additional characteristics are needed to derive an accurate risk score model in predicting post-transplant outcomes among recipients with ACLF-3.

Relatively Poor Long-term Outcomes Following Liver Transplantation for NASH in the United States

BACKGROUND

Nonalcoholic steatohepatitis (NASH) continues to increase in frequency as an indication for liver transplantation (LT). Data on long-term outcomes for these patients are limited. We aimed to compare long-term patient and graft survival in patients undergoing LT for NASH in the United States to other indications.

METHODS

We analyzed data from the Scientific Registry of Transplant Recipients of adult patients who underwent primary deceased-donor LT from January 1, 2005, to December 31, 2019.

RESULTS

NASH has increased as an indication for LT by 4.5-fold, from 5.2% in 2005 to 23.4% in 2019. Patient (61.2%) and graft survival (59.2%) at 10 y are significantly poorer for NASH than for all other indications other than alcohol. Patients transplanted for NASH have higher body mass index (32.2 versus 27.6) and greater frequency of diabetes (13% versus 11.6%) than any other indication (P < 0.001). Portal vein thrombosis, location in intensive care unit, dialysis, and pre-LT diabetes (P < 0.001 for all) are independently predictive of patient death and graft loss. Body mass index is not predictive. NASH patients undergoing simultaneous liver kidney have markedly worse 10-y patient and graft survival than liver-only (52.3% versus 62.1%). Graft loss was attributed to recurrence of NASH in <1% of patients.

CONCLUSIONS

LT for NASH is associated with relatively poor long-term patient and graft survival when compared with patients transplanted for other indications, NASH patients undergoing simultaneous liver kidney have the worst long-term outcomes.

Recent Progress and Future Direction for the Application of Multiomics Data in Clinical Liver Transplantation

Omics data address key issues in liver transplantation (LT) as the most effective therapeutic means for end-stage liver disease. The purpose of this study was to review the current application and future direction for omics in LT. We reviewed the use of multiomics to elucidate the pathogenesis leading to LT and prognostication. Future directions with respect to the use of omics in LT are also described based on perspectives of surgeons with experience in omics. Significant molecules were identified and summarized based on omics, with a focus on post-transplant liver fibrosis, early allograft dysfunction, tumor recurrence, and graft failure. We emphasized the importance omics for clinicians who perform LTs and prioritized the directions that should be established. We also outlined the ideal workflow for omics in LT. In step with advances in technology, the quality of omics data can be guaranteed using an improved algorithm at a lower price. Concerns should be addressed on the translational value of omics for better therapeutic effects in patients undergoing LT.

Re-thinking of T-tube use in whole liver transplantation: an analysis on the risk of delayed graft function

The liver–gut axis has been identified as crucial mediator of liver regeneration. Thus, the use of a T-tube in liver transplantation (LT), which interrupts the enterohepatic bile circulation, may potentially have a detrimental effect on the early allograft functional recovery. We retrospectively analyzed a cohort of 261 patients transplanted with a whole liver graft, with a duct-to-duct biliary anastomosis, who did not develop any surgical complication within postoperative day 14. Early allograft dysfunction (EAD) was defined according to the criteria of Olthoff et al. (EAD-O), and graded according to the Model for Early Allograft Function (MEAF) score. EAD-O developed in 24.7% of recipients and the median MEAF score was 4.0 [interquartile range 2.9–5.5]. Both MEAF and EAD predicted 90-day post-LT mortality. A T-tube was used in 49.4% of cases (n = 129). After a propensity score matching for donor age, cold and warm ischemia time, donor risk index, balance of risk score, Child–Pugh class C, and MELD score, the T-tube group showed a significantly higher prevalence of EAD-O and value of MEAF than the no-T-tube group (EAD-O: 29 [34.1%] vs 16 [19.0%], p = 0.027; MEAF 4.5 [3.5–5.7] vs 3.7 [2.9–5.0], p = 0.014). In conclusion, T-tube use in LT may be a risk factor for EAD and higher MEAF, irrespective of graft quality and severity of pre-LT liver disease.

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.

Proposal and validation of a liver graft discard score for liver transplantation from deceased donors: a multicenter Italian study

Several studies have explored the risk of graft dysfunction after liver transplantation (LT) in recent years. Conversely, risk factors for graft discard before or at procurement have poorly been investigated. The study aimed at identifying a score to predict the risk of liver-related graft discard before transplantation. Secondary aims were to test the score for prediction of biopsy-related negative features and post-LT early graft loss. A total of 4207 donors evaluated during the period January 2004–Decemeber 2018 were retrospectively analyzed. The group was split into a training set (n = 3,156; 75.0%) and a validation set (n = 1,051; 25.0%). The Donor Rejected Organ Pre-transplantation (DROP) Score was proposed: − 2.68 + (2.14 if Regional Share) + (0.03*age) + (0.04*weight)-(0.03*height) + (0.29 if diabetes) + (1.65 if anti-HCV-positive) + (0.27 if HBV core) − (0.69 if hypotension) + (0.09*creatinine) + (0.38*log10AST) + (0.34*log10ALT) + (0.06*total bilirubin). At validation, the DROP Score showed the best AUCs for the prediction of liver-related graft discard (0.82; p < 0.001) and macrovesicular steatosis ≥ 30% (0.71; p < 0.001). Patients exceeding the DROP 90th centile had the worse post-LT results (3-month graft loss: 82.8%; log-rank P = 0.024).The DROP score represents a valuable tool to predict the risk of liver function-related graft discard, steatosis, and early post-LT graft survival rates. Studies focused on the validation of this score in other geographical settings are required.

Improved Survival With Higher-risk Donor Grafts in Liver Transplant With Acute-on-chronic Liver Failure

Supplemental Digital Content is available in the text.

Use of higher-risk grafts in liver transplantation for patients with acute-on-chronic liver failure (ACLF) has been associated with poor outcomes. This study analyzes trends in liver transplantation outcomes for ACLF over time based on the donor risk index (DRI).

Determinants of short-term outcomes after pediatric liver transplantation: a single centre experience over 20 years

BACKGROUND

Liver transplantation (LT) is a standard-of-care therapeutic modality for selected patients with life-threatening liver disease, including children. In addition to specific clinical characteristics of pediatric LT recipients due to initial liver disease (and related comorbidities) and level of liver failure, early postoperative outcome may be dependent on the surgical technique used, related to the type of organ donor and graft. Therefore, the aims of the present retrospective study from a large single centre cohort were to identify the prognostic factors for both 1-year patient and graft survival.

METHODS

Between October 1990 and October 2010, 151 children underwent a first LT in our centre.

RESULTS

The mean age was 5.3 ± 7.4 years, and the main indication was biliary atresia (BA) (49.0%). Living donor liver transplantation (LDLT) was performed in 39 cases (25.8%). Cadaveric liver graft was a whole liver in 50 cases (33.1%) and a partial liver (reduced or split) in 62 cases (41.1%). One-year patient and graft survival rates were 88.7% and 86.1%, respectively. Multivariate analysis disclosed that initial liver disease, location at time of LT, donor/recipient (D/R) delta age, early post-transplant hemodialysis and initial immunosuppression (induction) were significantly associated with patient survival and that D/R delta age, primary non-function, early post-transplant hemodialysis and initial immunosuppression (induction) were significantly associated with graft survival.

CONCLUSION

The results of our single-centre experience of pediatric LT emphasize that early patient and graft survivals depend on pre-operative/operative factors such as initial liver disease, D/R delta age and immunosuppressive regimen. Awareness of these factors can help in the decision making for children requiring LT.

Predicting Early Extubation After Liver Transplantation: External Validation and Improved Generalizability of a Proposed Fast-track Score

BACKGROUND

Early extubation of liver transplantation recipients is a cornerstone of fast-track (FT) pathways. Identifying suitable candidates has previously been accomplished using perioperative variables to develop a FT probability score. The objective of this study was to externally validate a proposed FT score.

METHODS

Following Research Ethics Board approval, data were extracted on liver transplants conducted at a single center from 2009 to 2017. Data extracted included patient characteristics, intraoperative variables, and postoperative outcome variables. The proposed FT score utilized 9 variables: age, gender, body mass index, model of end-stage liver disease, retransplant, preoperative hospital admission, blood transfusion, operative time, and vasopressor use. We calculated the FT score in our cohort, and assessed the discrimination and calibration of the model. Score performance was explored by subgroup analyses, customization and altering the outcome definition.

RESULTS

The FT score was found to predict higher rates of successful FT than was observed in the external cohort (n = 1385) and had reduced discrimination (area under the receiver operating curve, 0.711; 95% confidence interval, 0.682-0.741) compared with the original internal validation cohort (area under the receiver operating curve, 0.830; 95% confidence interval, 0.789-0.871; P < 0.0001). Discrimination was improved by customizing the transfusion (P < 0.0001) components of the simplified score or by level 1 customization of all regression model coefficients (P < 0.0001). A time-based definition of FT (early extubation) did not alter the accuracy of the prediction score (P = 0.914), improving the model's generalizability.

CONCLUSIONS

The proposed FT score may help identify patients suitable for early extubation and FT pathways after liver transplantation in conjunction with clinical judgment.

Baseline haemoglobin and thromboelastometry are predictive of red blood cell requirements and one-year mortality in liver transplantation

BACKGROUND

To determine the predictive capacity of baseline haemoglobin and maxim clot firmness (MCF) EXTEM thromboelastometry for intraoperative red blood cell (RBC) requirements and its influence on mortality.

METHODS

591 adult liver transplant (LT) recipients from ten Spanish centres were reviewed. The main outcomes were the percentage of patients who received RBC and massive transfusion (≥ 6 RBC units), RBC units transfused, and mortality.

RESULTS

76 % received a donor after brain death graft and 24 % a controlled donor after circulatory death graft. Median (interquartile ranges) RBC transfusion was 2 (0-4) units, and 63 % of patients were transfused. Comparing transfused and non-transfused patients, mean (standard deviation) for baseline haemoglobin was 10.4 (2.1) vs. 13.0 (1.9) g/dl (p = 0.001), EXTEM MCF was 51(11) vs. 55(9) mm (p = 0.001). Haemoglobin and EXTEM MCF were inversely associated with the need of transfusion odds ratio (OR) of 0.558 (95 % CI 0.497-0.627, p < 0.001) and OR 0.966 (95 % CI0.945-0.987, p = 0.002), respectively. Pre-operative baseline haemoglobin ≤ 10 g/dL predicted RBC transfusion, sensitivity of 93 % and specificity of 47 %. Massive transfusion (MT) was received by 19 % of patients. Haemoglobin ≤10 g/dL predicted MT with sensitivity 73 % and specificity of 52 %. One-year patient and graft survival were significantly lower in patients who required MT (78 % and 76 %, respectively) vs. those who did not (94 % and 93 %, respectively).

DISCUSSION

whereas EXTEM MCF is less dreterminant predicting RBC requirements, efforts are required to improve preoperative haemoglobin up to 10 g/dl in patients awaiting LT.

Liver Transplantation in Acute-on-chronic Liver Failure

Liver transplantation (LT) has revolutionized outcomes for cirrhotic patients. Current liver allocation policies dictate patients with highest short-term mortality receive the highest priority, thus, several patients become increasingly ill on the waitlist. Given cirrhosis is a progressive disease, it can be complicated by the occurrence of acute-on-chronic liver failure (ACLF), a syndrome defined by an acute deterioration of liver function associated with extrahepatic organ failures requiring intensive care support and a high short-term mortality. Successfully bridging to transplant includes accurate prognostication and prioritization of ACLF patients awaiting LT, optimizing intensive care support pre-LT, and tailoring immunosuppressive and anti-infective therapies post-LT. Furthermore, predicting futility (too sick to undergo LT) in ACLF is challenging. In this review, we summarize the role of LT in ACLF specifically highlighting (a) current prognostic scores in ACLF, (b) critical care management of the ACLF patient awaiting LT, (c) donor issues to consider in transplant in ACLF, and (d) exploring of recent post-LT outcomes in ACLF and potential opportunities to improve outcomes including current care gaps and unmet research needs.

Expression of MICA in Zero Hour Biopsies Predicts Graft Survival After Liver Transplantation

In search for novel biomarkers to assess graft quality, we investigated whether defined candidate genes are predictive for outcome after liver transplantation (LT).

Zero-hour liver biopsies were obtained from 88 livers. Gene expression of selected candidate markers was analyzed and correlated with clinical parameters as well as short and long-term outcomes post LT. Whereas both, the calculated Eurotransplant Donor-Risk-Index and the donor body mass index, had either a poor or no predictive value concerning serum levels indicative for liver function (ALT, AST, GGT, bilirubin) after 6 months, chronological donor age was weakly predictive for serum bilirubin (AUC=0.67). In contrast, the major histcompatibility complex class I related chain A (MICA) mRNA expression demonstrated a high predictive value for serum liver function parameters revealing an inverse correlation (e.g. for ALT: 3 months p=0.0332; 6 months p=0.007, 12 months 0.0256, 24 months p=0.0098, 36 months, p=0.0153) and proved significant also in a multivariate regression model. Importantly, high expression of MICA mRNA revealed to be associated with prolonged graft survival (p=0.024; log rank test) after 10 years of observation, whereas low expression was associated with the occurrence of death in patients with transplant related mortality (p=0.031). Given the observed correlation with short and long-term graft function, we suggest MICA as a biomarker for pre-transplant graft evaluation.

Association between intraoperative fluid balance, vasopressors and graft complications in liver transplantation: A cohort study

Introduction

Biliary complications following liver transplantation are common. The effect of intraoperative fluid balance and vasopressors on these complications is unknown.

Materials and methods

We conducted a cohort study between July 2008 and December 2017. Our exposure variables were the total intraoperative fluid balance and the use of vasopressors on ICU admission. Our primary outcome was any biliary complication (anastomotic and non-anastomotic strictures) up to one year after transplantation. Our secondary outcomes were vascular complications, primary graft non-function and survival.

Results

We included 562 consecutive liver transplantations. 192 (34%) transplants had a biliary complication, 167 (30%) had an anastomotic stricture and 56 had a non-anastomotic stricture (10%). We did not observe any effect of intraoperative fluid balance or vasopressor on biliary complications (HR = 0.97; 95% CI, 0.93 to 1.02). A higher intraoperative fluid balance was associated with an increased risk of primary graft non-function (non-linear) and a lower survival (HR = 1.40, 95% CI, 1.14 to 1.71) in multivariable analyses.

Conclusion

Intraoperative fluid balance and vasopressors upon ICU admission were not associated with biliary complications after liver transplantation but may be associated with other adverse events. Intraoperative hemodynamic management must be prospectively studied to further assess their impact on liver recipients’ outcomes.

Analysis of factors associated with discrepancies between predicted and observed liver weight in liver transplantation

BACKGROUND

Even using predictive formulas based on anthropometrics in about 30% of subjects, liver weight (LW) cannot be predicted with a ≤20% margin of error. We aimed to identify factors associated with discrepancies between predicted and observed LW.

METHODS

In 500 consecutive liver grafts, we tested LW predictive performance using 17 formulas based on anthropometric characteristics. Hashimoto's formula (961.3 × BSA_D-404.8) was associated with the lowest mean absolute error and used to predict LW for the entire cohort. Clinical factors associated with a ≥20% margin of error were identified in a multivariable analysis after propensity score matching (PSM) of donors with similar anthropometric characteristics.

RESULTS

The total LW was underestimated with a ≥20% margin of error in 53/500 (10.6%) donors and overestimated in 62/500 (12%) donors. After PSM analysis, ages ≥ 65, (OR = 3.21; CI95% = 1.63-6.31; P = .0007), age ≤ 30 years, (OR = 2.92; CI95% = 1.15-7.40; P = .02), and elevated gamma-glutamyltransferase (GGT) levels (OR = 0.98; CI95% = 0.97-0.99; P = .006), influenced the risk of LW overestimation. Age ≥ 65 years, (OR = 5.98; CI95% = 2.28-15.6; P = .0002), intensive care unit (ICU) stay with ventilation > 7 days, (OR = 0.32; CI95% = 0.12-0.85; P = .02) and waist circumference increase (OR = 1.02; CI95% = 1.00-1.04; P = .04) were factors associated with LW underestimation.

CONCLUSIONS

Increased waist circumference, age, prolonged ICU stay with ventilation, elevated GGT were associated with an increase in the margin of error in LW prediction. These factors and anthropometric characteristics could help transplant surgeons during the donor-recipient matching process.

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.

Early Allograft Dysfunction Increases Hospital Associated Costs After Liver Transplantation-A Propensity Score-Matched Analysis

Concepts to ameliorate the continued mismatch between demand for liver allografts and supply include the acceptance of allografts that meet extended donor criteria (ECD). ECD grafts are generally associated with an increased rate of complications such as early allograft dysfunction (EAD). The costs of liver transplantation for the health care system with respect to specific risk factors remain unclear and are subject to change. We analyzed 317 liver transplant recipients from 2013 to 2018 for outcome after liver transplantation and hospital costs in a German transplant center. In our study period, 1-year survival after transplantation was 80.1% (95% confidence interval: 75.8%-84.6%) and median hospital stay was 33 days (interquartile rage: 24), with mean hospital costs of €115,924 (SD €113,347). There was a positive correlation between costs and laboratory Model for End-Stage Liver Disease score (r_s = 0.48, P < 0.001), and the development of EAD increased hospital costs by €26,229. ECD grafts were not associated with a higher risk of EAD in our cohort. When adjusting for recipient-associated risk factors such as laboratory Model for End-Stage Liver Disease score, recipient age, and split liver transplantation with propensity score matching, only EAD and cold ischemia increased total costs. Conclusion: Our data show that EAD leads to significantly higher hospital costs for liver transplantation, which are primarily attributed to recipient health status. Strategies to reduce the incidence of EAD are needed to control costs in liver transplantation.

Effect of Donor Transaminase Levels on Graft Survival Following Liver Transplant: An Analysis of the Organ Procurement and Transplantation Network Database

OBJECTIVES

Despite data showing equivalent outcomes between grafts from marginal versus standard criteria deceased liver donors, elevated donor transaminases constitute a frequent reason to decline potential livers. We assessed the effect of donor transaminase levels and other characteristics on graft survival.

MATERIALS AND METHODS

We performed a retrospective cohort analysis of adult first deceased donor liver transplant recipients with available transaminase levels registered in the Organ Procurement and Transplantation Network database (2008-2018). We used Cox proportional hazards regression to determine the effects of donor characteristics on graft survival.

RESULTS

Of 53 913 liver transplants, 52 158 were allografts from donors with low transaminases (≤ 500 U/L; group A) and 1755 were from donors with elevated transaminases (> 500 U/L; group B). Group A recipients were more likely to be hospitalized (P = .01) or in intensive care (P < .001) or to have mechanical assistance (P < .001), portal vein thrombosis (P = .01), diabetes mellitus (P = .003), or dialysis the week before liver transplant (P = .004). Multivariable analysis (controlling for recipient characteristics) showed donor risk factors of graft failure included diabetes mellitus (P < .001), donation after cardiac death (P < .001), total bilirubin > 3.5 mg/dL (P < .001), serum creatinine > 1.5 mg/dL (P = .01), and cold ischemia time > 6 hours (P < .001). Regional organ sharing showed lower risk of graft failure (P = .02). Donor transaminases > 500 U/L were not associated with graft failure (relative risk, 1.02; 95% CI, 0.91-1.14; P = .74).

CONCLUSIONS

Donor transaminases > 500 U/L should not preclude the use of liver grafts. Instead, donor total bilirubin > 3.5 mg/dL and serum creatinine > 1.5 mg/dL appear to be associated with higher likelihood of graft failure after liver transplant.

Transplant of Elderly Patients: Is There an Upper Age Cutoff?

Increased life expectancy and advances in the care of chronic liver disease has increased the number of elderly patients needing liver transplant. Organ donation policies prioritize transplant to the sickest. There is an ongoing debate with regard to balancing the principles of equity and utility. Several hospitals have adopted center-specific policies and there has been an increased trend of transplant in elderly patients since 2002. Appropriate patient selection and long-term outcomes in the setting of limited organ availability pose several challenges. This article reviews the data and discusses the pros and cons of transplants in the elderly.

A Novel Preservation Solution Containing Quercetin and Sucrose for Porcine Kidney Transplantation

In organ transplantation, the University of Wisconsin (UW) solution has been the gold standard for organ preservation. Quercetin (Que) has numerous antioxidant and anti-inflammatory activities, and sucrose (Suc) may be effective for cold storage (CS). This study aimed to investigate the in vitro protective effect of Que and Suc on cold injury to the kidney and to determine whether Que + Suc could improve ischemia-reperfusion injury during CS and hypothermic oxygenated perfusion (HOPE) in autologous transplantation models.

METHODS

BHK-21 cells were stored at 4°C for 3 days in UW solution for CS/machine perfusion (CS/MP-UW) with Que (33.1 μM, 3.3 μM, 0.33 μM) and Suc (0.1 M). In a porcine model of renal autologous transplantation, left kidney grafts were preserved under 3 conditions: group 1, CS preservation for 24 hours; group 2, CS preservation for 22 hours and HOPE with CS/MP-UW solution for 2 hours; and group 3, identical preservation as group 2, with Que and Suc added to the solution. Animals were euthanized on day 7 after autologous transplantation.

RESULTS

After 3 days of CS preservation, the CS/MP-UW solution with Que (33.1 μM, 3.3 μM) and Suc showed significant cell protection against cold injury. In the porcine model of renal autologous transplantation, the last blood Cre level and the blood lipid hydroperoxide on posttransplantation day 2 were significantly different between group 1 and group 3. Moreover, the total endothelial, glomerular, tubular, interstitial (EGTI) histology score in the kidney tissue was also significantly different. Regarding the change in renal resistance in HOPE, the decrease observed in group 3 was significantly larger than that in group 2.

CONCLUSIONS

Our results suggest that the addition of Que and Suc to a UW solution can improve kidney preservation and could potentially enhance the outcome of kidney transplantation.

Organ utilization - the next hurdle in transplantation?

Nonutilization of organs from consented deceased donors remains a significant factor in limiting patient access to transplantation. Critical to reducing waste is a clear understanding of why organs are not used: accurate metrics are essential to identify the extent and causes of waste but use of these measures as targets or comparators between units/jurisdictions must be done with caution as focus on any one measure may result in unintended adverse consequences. Comparison between centres or countries may be misleading because of variation in definitions, patient or graft characteristics. Two of the most challenging areas to improve appropriate deceased donor organ utilization are appetite for risk and lack of validated tools to help identify an organ that will function appropriately. Currently, the implanting surgeon is widely considered to be accountable for the use of a donated organ so guidelines must be clear to allow and support sensible decisions and recognition that graft failure or inadvertent disease transmission are not necessarily attributable to poor decision-making. Accepting an organ involves balancing risk and benefit for the potential recipient. Novel technologies such as machine perfusion may allow for more robust guidance as to the functioning of the organ.

RELATIONSHIP BETWEEN DONOR QUALITY AND RECIPIENT GRAVITY IN LIVER TRANSPLANT

Background:

Tools such as MELD score and DRI are currently used to predict risks and benefits on liver allocation for transplantation.

Aim:

To evaluate the relation between donor quality and recipient severity on liver allocation.

Methods:

Liver transplants performed in 2017 and 2018 were evaluated. Data were collected from Paraná’s State Government Registry. DRI was evaluated in relation to recipient MELD score and position on waiting list.

Results:

It was observed relation between DRI and position on waiting list: higher risk organs were allocated to recipients with worse waiting list position. There was no relation between DRI and MELD score. Afrodescendents and elderly donor organs were allocated to lower MELD score and worse waiting list position recipients.

Conclusion:

There is no relation between DRI and MELD on liver allocation. However, DRI interferes with allocation decision based on recipients waiting list position. Donor race and age interfere on both recipient MELD score and waiting list position

Metabonomic Profile of Macrosteatotic Allografts for Orthotopic Liver Transplantation in Patients With Initial Poor Function: Mechanistic Investigation and Prognostic Prediction

BACKGROUND

Our previous study revealled amplified hazardous effects of macrosteatosis (MaS) on graft failure (GF) in recipients with severe liver damage in short post-operative days, with vague mechanism inside.

AIM

We aimed to uncover the molecular mechanism of donor MaS on GF, and construct the predictive model to monitor post-transplant prognosis based on "omics" perspective.

METHODS

Ultra-performance liquid chromatography coupled to mass spectrometry metabolomic analysis was performed in allograft tissues from 82 patients with initial poor function (IPF) from multi-liver transplant (LT) centers. Pathway analysis was performed by on-line toolkit Metaboanalyst (v 3.0). Predictive model was constructed based on combinative metabonomic and clinical data extracted by stepwised cox proportional analysis.

RESULTS

Principle component analysis (PCA) analysis revealled stratification on metabolic feature in organs classified by MaS status. Differential metabolits both associated with MaS and GF were significantly enriched on pathway of glycerophospholipid metabolism (P < 0.05). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) involved in glycerophospholipid metabolism was significantly decreased in cases with MaS donors and GF (P < 0.05). Better prediction was observed on graft survival by combinative model (area under the curve = 0.91) and confirmed by internal validation.

CONCLUSION

Metabonomic features of allografts can be clearly distinguished by MaS status in patients with IPF. Dysfunction on glycerophospholipid metabolism was culprit to link donor MaS and final GF. Decrement on PC and PE exerted the fatal effects of MaS on organ failure. Metabonomic data might help for monitoring long-term graft survival after LT.

[Declined Liver Grafts - Analysis of the German Donor Population from 2010 to 2018]

BACKGROUND

 The lack of suitable allografts limits the availability of liver transplantation in Germany. The quality of potentially available German donor livers has to date not been analyzed.

METHODS

 Analysis of all donors for potential liver transplantations reported to the Eurotransplant by the German Organ Transplantation Foundation from 2010 to 2018. Categorization of transplanted and discarded organs utilizing available histopathological reports and predefined extended criteria for organ donation.

RESULTS

 A total of 8594 livers were offered for transplantation, of which 15.2 % were discarded. During the analysis period the proportion of donor livers from extended criteria donors increased from 65 % to 70 % (p = 0.005). In 2018, 21.3 % of offered donor livers were discarded, more than half (56.4 %) of these organs came from donors meeting multiple extended criteria. Livers were significantly more likely to be not transplanted, when from donors of older age (> 65 years; 41 vs. 28 %), BMI > 30 kg/m² (29 vs. 14 %) or elevated transaminase levels (all p < 0,001).

CONCLUSION

 Despite the consistent organ scarcity in Germany, a relevant amount of livers cannot be transplanted due to a multitude of organ quality limitations. This should stimulate the search for concepts such as normothermic ex vivo machine perfusion to evaluate, protect and potentially improve organ quality.

Using Artificial Intelligence for Predicting Survival of Individual Grafts in Liver Transplantation: A Systematic Review

The demand for liver transplantation far outstrips the supply of deceased donor organs, and so, listing and allocation decisions aim to maximize utility. Most existing methods for predicting transplant outcomes use basic methods, such as regression modeling, but newer artificial intelligence (AI) techniques have the potential to improve predictive accuracy. The aim was to perform a systematic review of studies predicting graft outcomes following deceased donor liver transplantation using AI techniques and to compare these findings to linear regression and standard predictive modeling: donor risk index (DRI), Model for End-Stage Liver Disease (MELD), and Survival Outcome Following Liver Transplantation (SOFT). After reviewing available article databases, a total of 52 articles were reviewed for inclusion. Of these articles, 9 met the inclusion criteria, which reported outcomes from 18,771 liver transplants. Artificial neural networks (ANNs) were the most commonly used methodology, being reported in 7 studies. Only 2 studies directly compared machine learning (ML) techniques to liver scoring modalities (i.e., DRI, SOFT, and balance of risk [BAR]). Both studies showed better prediction of individual organ survival with the optimal ANN model, reporting an area under the receiver operating characteristic curve (AUROC) 0.82 compared with BAR (0.62) and SOFT (0.57), and the other ANN model gave an AUC ROC of 0.84 compared with a DRI (0.68) and SOFT (0.64). AI techniques can provide high accuracy in predicting graft survival based on donors and recipient variables. When compared with the standard techniques, AI methods are dynamic and are able to be trained and validated within every population. However, the high accuracy of AI may come at a cost of losing explainability (to patients and clinicians) on how the technology works.

Feasibility of Large Liver Grafts in Adults

INTRODUCTION

Size mismatch between donor and recipients may negatively influence postoperative results of liver transplantation (LT). In deceased donor LT for adults, large grafts are occasionally rejected due to the fear of primary nonfunction. The aim of this study is to assess the feasibility of using large liver grafts in adults undergoing deceased donor LT.

METHODS

We performed a retrospective study including adult patients who underwent deceased donor LT at our center between January 2006 and September 2019. Recipients with donors aged less than 18 years and those receiving split-liver grafts were excluded. Graft weight of 1800 grams was the cutoff used to divide patients in 2 groups: group 1 (graft weighing < 1800 g) and group 2 (grafts weighing ≥ 1800 g).

RESULTS

A total of 806 patients were included in the study. group 1 and 2 included 722 and 84 recipients, respectively. A larger proportion of male recipients was obseved in group 2: 64.8% vs 76.2% (P = .0037). Mean graft weight in group 1 and 2 was, respectively, 1348 ± 231.81 g and 1986.57 ± 165.51 g (P < .001), which resulted in significantly higher graft weight/recipient weight ratio and graft weight/standard liver volume ratio in group 2. In group 2, there were 9 (10.71%) patients with portal vein thrombosis as well as 24 patients (28.5%) with bulky ascites and 44 grafts (52.3%) with steatosis. Primary closure of the abdominal wall was not possible in 5 patients (5.9%) from this group. Primary nonfunction was diagnosed in 14 cases (16.6%), with liver retransplantation being performed in 6 of them. Male to female sex combination occurred in 19% of LT in group 2.

CONCLUSION

The use of large grafts is feasible; however, proper matching between donor and recipient is paramount, especially taking into consideration graft steatosis, portal vein thrombosis and the presence of bulky ascites.

Cell release during perfusion reflects cold ischemic injury in rat livers

The global shortage of donor organs has made it crucial to deeply understand and better predict donor liver viability. However, biomarkers that effectively assess viability of marginal grafts for organ transplantation are currently lacking. Here, we showed that hepatocytes, sinusoidal endothelial, stellate, and liver-specific immune cells were released into perfusates from Lewis rat livers as a result of cold ischemia and machine perfusion. Perfusate comparison analysis of fresh livers and cold ischemic livers showed that the released cell profiles were significantly altered by the duration of cold ischemia. Our findings show for the first time that parenchymal cells are released from organs under non-proliferative pathological conditions, correlating with the degree of ischemic injury. Thus, perfusate cell profiles could serve as potential biomarkers of graft viability and indicators of specific injury mechanisms during organ handling and transplantation. Further, parenchymal cell release may have applications in other pathological conditions beyond organ transplantation.

Perioperative Opioid Use and Chronic Post-Surgical Pain after Liver Transplantation: A Single Center Observational Study

OBJECTIVES

To investigate the opioid requirements and prevalence of chronic postsurgical pain (CPSP) in liver transplant (LT) recipients and to evaluate the association of opioid use with postoperative survival.

DESIGN

Retrospective analysis.

SETTING

A large academic medical center.

PATIENTS

Cadaveric liver transplants recipients from 2008 to 2016.

INTERVENTIONS

Analysis of demographic, perioperative, and outcome data.

MEASUREMENTS AND MAIN RESULTS

This study measured the incidence and quantity of preoperative opioid use, postoperative opioid requirements, the incidence of CPSP, and survival in patients with and without CPSP. Opioid requirements were calculated in morphine milligram equivalents. In total, 322 LT recipients satisfied the inclusion criteria. The cohort of interest included 61 patients (18.9%) who were prescribed opioids before LT, compared to the control group of 261. Postoperative opioid requirements were significantly higher in the cohort of interest in the first 24 hours (205.9 ± 318.5 v 60.4 ± 33.6 mg, p < 0.0001) and at 7 days after transplant (57.0 ± 70.6 mg v 19.2 ± 15.4 mg, p < 0.0001). Incidence of CPSP was significantly higher in the cohort of interest at 3 months (70.5% v 45.5%, p < 0.0001), at 2 years (38% v 12%), and at 5 years (29.8% v 6.9%) postoperatively. CPSP was a significant risk factor for patient mortality after transplantation (p = 0.038, HR 1.26).

CONCLUSIONS

Opioid use is relatively frequent in patients waiting for LT. It significantly affects the postoperative opioid requirements and the incidence of CSPS. CPSP may significantly affect survival after LT.