Improved assessment of donor liver steatosis using Banff consensus recommendations and deep learning algorithms.

BACKGROUND & AIMS: The Banff Liver Working Group recently published consensus recommendations for steatosis assessment in donor liver biopsy, but few studies reported their use and no automated deep-learning algorithms based on the proposed criteria have been developed so far. We evaluated Banff recommendations on a large monocentric series of donor liver needle biopsies by comparing pathologists' scores with those generated by convolutional neural networks (CNNs) we specifically developed for automated steatosis assessment. METHODS: We retrospectively retrieved 292 allograft liver needle biopsies collected between January 2016 and January 2020 and performed steatosis assessment using a former intra-institution method (pre-Banff method) and the newly introduced Banff recommendations. Scores provided by pathologists and CNN models were then compared, and the degree of agreement was measured with the intraclass correlation coefficient (ICC). RESULTS: Regarding the pre-Banff method, poor agreement was observed between the pathologist and CNN models for small droplet macrovesicular steatosis (ICC: 0.38), large droplet macrovesicular steatosis (ICC: 0.08), and the final combined score (ICC: 0.16) evaluation, but none of these reached statistically significance. Interestingly, significantly improved agreement was observed using the Banff approach: ICC was 0.93 for the low-power score (p <0.001), 0.89 for the high-power score (p <0.001), and 0.93 for the final score (p <0.001). Comparing the pre-Banff method with the Banff approach on the same biopsy, pathologist and CNN model assessment showed a mean (±SD) percentage of discrepancy of 26.89 (±22.16) and 1.20 (±5.58), respectively. CONCLUSIONS: Our findings support the use of Banff recommendations in daily practice and highlight the need for a granular analysis of their effect on liver transplantation outcomes. IMPACT AND IMPLICATIONS: We developed and validated the first automated deep-learning algorithms for standardized steatosis assessment based on the Banff Liver Working Group consensus recommendations. Our algorithm provides an unbiased automated evaluation of steatosis, which will lay the groundwork for granular analysis of steatosis's short- and long-term effects on organ viability, enabling the identification of clinically relevant steatosis cut-offs for donor organ acceptance. Implementing our algorithm in daily clinical practice will allow for a more efficient and safe allocation of donor organs, improving the post-transplant outcomes of patients.

Liver transplantation with uncontrolled versus controlled DCD donors using normothermic regional perfusion and ex-situ machine perfusion.

In Italy, 20 minutes of continuous, flat-line electrocardiogram are required for death declaration, which significantly increases the risks of donation after circulatory death (DCD) LT. Despite prolonged warm ischemia time, Italian centers reported good outcomes in controlled donation after circulatory death LT by combining normothermic regional and end-ischemic machine perfusion. However, data on uncontrolled DCD (uDCD) LT performed by this approach are lacking. This was a multicenter, retrospective study performed at 3 large-volume centers comparing clinical outcomes of uncontrolled versus controlled DCD LT. The aim of the study was to assess outcomes of sequential normothermic regional perfusion and end-ischemic machine perfusion in uncontrolled DCD liver transplantation (LT). Of 153 DCD donors evaluated during the study period, 40 uDCD and 59 donation after circulatory death grafts were transplanted (utilization rate 52% vs. 78%, p = 0.004). Recipients of uDCD grafts had higher MEAF (4.9 vs. 3.5, p < 0.001) and CCI scores at discharge (24.4 vs. 8.7, p = 0.026), longer ICU stay (5 vs. 4 d, p = 0.047), and a trend toward more severe AKI. At multivariate analysis, 90-day graft loss was associated with recipient BMI and lactate downtrend during normothermic regional perfusion. One-year graft survival was lower in uDCD (75% vs. 90%, p = 0.007) but became comparable when non-liver-related graft losses were treated as censors (77% vs. 90%, p = 0.100). The incidence of ischemic cholangiopathy was 10% in uDCD versus 3% in donation after circulatory death, p = 0.356. uDCD LT with prolonged warm ischemia is feasible by the sequential use of normothermic regional perfusion and end-ischemic machine perfusion. Proper donor and recipient selection are key to achieving good outcomes in this setting.

Recipient hepatectomy technique may affect oncological outcomes of liver transplantation for hepatocellular carcinoma.

To date, caval sparing (CS) and total caval replacement (TCR) for recipient hepatectomy in liver transplantation (LT) have been compared only in terms of surgical morbidity. Nonetheless, the CS technique is inherently associated with an increased manipulation of the native liver and later exclusion of the venous outflow, which may increase the risk of intraoperative shedding of tumor cells when LT is performed for HCC. A multicenter, retrospective study was performed to assess the impact of recipient hepatectomy (CS vs. TCR) on the risk of posttransplant HCC recurrence among 16 European transplant centers that used either TCR or CS recipient hepatectomy as an elective protocol technique. Exclusion criteria comprised cases of non-center-protocol recipient hepatectomy technique, living-donor LT, HCC diagnosis suspected on preoperative imaging but not confirmed at the pathological examination of the explanted liver, HCC in close contact with the IVC, and previous liver resection for HCC. In 2420 patients, CS and TCR approaches were used in 1452 (60%) and 968 (40%) cases, respectively. Group adjustment with inverse probability weighting was performed for high-volume center, recipient age, alcohol abuse, viral hepatitis, Child-Pugh class C, Model for End-Stage Liver Disease score, cold ischemia time, clinical HCC stage within Milan criteria, pre-LT downstaging/bridging therapies, pre-LT alphafetoprotein serum levels, number and size of tumor nodules, microvascular invasion, and complete necrosis of all tumor nodules (matched cohort, TCR, n = 938; CS, n = 935). In a multivariate cause-specific hazard model, CS was associated with a higher risk of HCC recurrence (HR: 1.536, p = 0.007). In conclusion, TCR recipient hepatectomy, compared to the CS approach, may be associated with some protective effect against post-LT tumor recurrence.

Combined transarterial chemoembolization and thermal ablation in candidates to liver transplantation with hepatocellular carcinoma: pathological findings and post-transplant outcome.

OBJECTIVES: Evaluating the pathological response and the survival outcomes of combined thermal ablation (TA) and transarterial chemoembolization (TACE) as a bridge or downstaging for liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) > 3 cm. MATERIALS AND METHODS: A retrospective review encompassed 36 consecutive patients who underwent combined TA-TACE as bridging or downstaging before LT. Primary objectives included necrosis of the target lesion at explant pathology, post-LT overall survival (OS) and post-LT recurrence-free survival (RFS). For OS and RFS, a comparison with 170 patients subjected to TA alone for nodules <3 cm in size was also made. RESULTS: Out of the 36 patients, 63.9% underwent TA-TACE as bridging, while 36.1% required downstaging. The average node size was 4.25 cm. All cases were discussed in a multidisciplinary tumor board to assess the best treatment for each patient. Half received radiofrequency (RF), and the other half underwent microwave (MW). All nodes underwent drug-eluting beads (DEB) TACE with epirubicin. The mean necrosis percentage was 65.9% in the RF+TACE group and 83.3% in the MW+TACE group (p-value = 0.099). OS was 100% at 1 year, 100% at 3 years and 94.7% at 5 years. RFS was 97.2% at 1 year, 94.4% at 3 years and 90% at 5 years. Despite the different sizes of the lesions, OS and RFS did not show significant differences with the cohort of patients subjected to TA alone. CONCLUSIONS: The study highlights the effectiveness of combined TA-TACE for HCC>3 cm, particularly for bridging and downstaging to LT, achieving OS and RFS rates significantly exceeding 80% at 1, 3 and 5 years.

Liver transplantation for tumor entities.

PURPOSE OF REVIEW: Tumor entities represent an increasing indication for liver transplantation (LT). This review addresses the most contentious indications of LT in transplant oncology. RECENT FINDINGS: Patient selection based on tumor biology in LT for colorectal cancer liver metastases (CRLM) demonstrated promising long-term outcomes and preserved quality of life despite high recurrence rates. In selected cases, LT for intrahepatic cholangiocarcinoma (iCCA) is feasible, with acceptable survival even in high-burden cases responsive to chemotherapy. LT following a strict neoadjuvant protocol for perihilar cholangiocarcinoma (pCCA) resulted in long-term outcomes consistently surpassing benchmark values, and potentially outperforming liver resection. SUMMARY: While preliminary results are promising, prospective trials are crucial to define applications in routine clinical practice. Molecular profiling and targeted therapies pave the way for personalized approaches, requiring evolving allocation systems for equitable LT access.

Improving outcomes of in situ split liver transplantation in Italy over the last 25 years.

BACKGROUND & AIMS: Split liver transplant(ation) (SLT) is still considered a challenging procedure that is by no means widely accepted. We aimed to present data on 25-year trends in SLT in Italy, and to investigate if, and to what extent, outcomes have improved nationwide during this time. METHODS: The study included all consecutive SLTs performed from May 1993 to December 2019, divided into three consecutive periods: 1993-2005, 2006-2014, and 2015-2019, which match changes in national allocation policies. Primary outcomes were patient and graft survival, and the relative impact of each study period. RESULTS: SLT accounted for 8.9% of all liver transplants performed in Italy. A total of 1,715 in situ split liver grafts were included in the analysis: 868 left lateral segments (LLSs) and 847 extended right grafts (ERGs). A significant improvement in patient and graft survival (p <0.001) was observed with ERGs over the three periods. Predictors of graft survival were cold ischaemia time (CIT) <6 h (p = 0.009), UNOS status 2b (p <0.001), UNOS status 3 (p = 0.009), and transplant centre volumes: 25-50 cases vs. <25 cases (p = 0.003). Patient survival was significantly higher with LLS grafts in period 2 vs. period 1 (p = 0.008). No significant improvement in graft survival was seen over the three periods, where predictors of graft survival were CIT <6 h (p = 0.007), CIT <6 h vs. ≥10 h (p = 0.019), UNOS status 2b (p = 0.038), and UNOS status 3 (p = 0.009). Retransplantation was a risk factor in split liver graft recipients, with significantly worse graft and patient survival for both types of graft (p <0.001). CONCLUSIONS: Our analysis showed Italian SLT outcomes to have improved over the last 25 years. These results could help to dispel reservations regarding the use of this procedure. IMPACT AND IMPLICATIONS: Split liver transplant(ation) (SLT) is still considered a challenging procedure and is by no means widely accepted. This study included all consecutive in situ SLTs performed in Italy from May 1993 to December 2019. With more than 1,700 cases, it is one of the largest series, examining long-term national trends in in situ SLT since its introduction. The data presented indicate that the outcomes of SLT improved during this 25-year period. Improvements are probably due to better recipient selection, refinements in surgical technique, conservative graft-to-recipient matching, and the continuous, yet carefully managed, expansion of donor selection criteria under a strict mandatory split liver allocation policy. These results could help to dispel reservations regarding the use of this procedure.

Alternative forms of portal vein revascularization in liver transplant recipients with complex portal vein thrombosis.

BACKGROUND & AIMS: Complex portal vein thrombosis (PVT) is a challenge in liver transplantation (LT). Extra-anatomical approaches to portal revascularization, including renoportal (RPA), left gastric vein (LGA), pericholedochal vein (PCA), and cavoportal (CPA) anastomoses, have been described in case reports and series. The RP4LT Collaborative was created to record cases of alternative portal revascularization performed for complex PVT. METHODS: An international, observational web registry was launched in 2020. Cases of complex PVT undergoing first LT performed with RPA, LGA, PCA, or CPA were recorded and updated through 12/2021. RESULTS: A total of 140 cases were available for analysis: 74 RPA, 18 LGA, 20 PCA, and 28 CPA. Transplants were primarily performed with whole livers (98%) in recipients with median (IQR) age 58 (49-63) years, model for end-stage liver disease score 17 (14-24), and cold ischemia 431 (360-505) minutes. Post-operatively, 49% of recipients developed acute kidney injury, 16% diuretic-responsive ascites, 9% refractory ascites (29% with CPA, p <0.001), and 10% variceal hemorrhage (25% with CPA, p = 0.002). After a median follow-up of 22 (4-67) months, patient and graft 1-/3-/5-year survival rates were 71/67/61% and 69/63/57%, respectively. On multivariate Cox proportional hazards analysis, the only factor significantly and independently associated with all-cause graft loss was non-physiological portal vein reconstruction in which all graft portal inflow arose from recipient systemic circulation (hazard ratio 6.639, 95% CI 2.159-20.422, p = 0.001). CONCLUSIONS: Alternative forms of portal vein anastomosis achieving physiological portal inflow (i.e., at least some recipient splanchnic blood flow reaching transplant graft) offer acceptable post-transplant results in LT candidates with complex PVT. On the contrary, non-physiological portal vein anastomoses fail to resolve portal hypertension and should not be performed. IMPACT AND IMPLICATIONS: Complex portal vein thrombosis (PVT) is a challenge in liver transplantation. Results of this international, multicenter analysis may be used to guide clinical decisions in transplant candidates with complex PVT. Extra-anatomical portal vein anastomoses that allow for at least some recipient splanchnic blood flow to the transplant allograft offer acceptable results. On the other hand, anastomoses that deliver only systemic blood flow to the allograft fail to resolve portal hypertension and should not be performed.

Viability assessment and transplantation of fatty liver grafts using end-ischemic normothermic machine perfusion.

End-ischemic viability testing by normothermic machine perfusion (NMP) represents an effective strategy to recover liver grafts having initially been discarded for liver transplantation (LT). However, its results in the setting of significant (≥30%) macrovesicular steatosis (MaS) have not been specifically assessed. Prospectively maintained databases at two high-volume LT centers in Northern Italy were searched to identify cases of end-ischemic NMP performed to test the viability of livers with MaS ≥ 30% in the period from January 2019 to January 2022. A total of 14 cases were retrieved, representing 57.9% of NMP and 5.7% of all machine perfusion procedures. Of those patients, 10 (71%) received transplants. Two patients developed primary nonfunction (PNF) and required urgent re-LT, and both were characterized by incomplete or suboptimal lactate clearance during NMP. PNF cases were also characterized by higher perfusate transaminases, lower hepatic artery and portal vein flows at 2 h, and a lack of glucose metabolism in one case. The remaining eight patients showed good liver function (Liver Graft Assessment Following Transplantation risk score, -1.9 [risk, 13.6%]; Early Allograft Failure Simplified Estimation score, -3.7 [risk, 2.6%]) and had a favorable postoperative course. Overall, NMP allowed successful transplantation of 57% of livers with moderate-to-severe MaS. Our findings suggest that prolonged observation (≥6 h) might be required for steatotic livers and that stable lactate clearance is a fundamental prerequisite for their use.

Viability assessment of livers donated after circulatory determination of death during normothermic regional perfusion.

BACKGROUND: Abdominal normothermic regional perfusion (A-NRP) allows in-situ reperfusion and recovery of abdominal organs metabolism in donors after circulatory death (DCD). Besides improving liver transplantation outcomes, liver injury and function can be assessed during A-NRP. METHODS: To refine liver viability assessment during A-NRP, prospectively collected data of controlled DCD donors managed at our Institution between October 2019 and May 2022 were retrospectively analyzed. Baseline characteristics, procedural variables and A-NRP parameters of donors whose liver was successfully transplanted were compared to those of donors whose liver was discarded. RESULTS: Twenty-seven donors were included and in 20 (74%) the liver was accepted (positive outcome). No differences between study groups were observed concerning baseline characteristics and warm ischemia times (WIT). Initial lactate levels were positively correlated with functional WIT (r2 = 0.4, p = 0.04), whereas transaminase levels were not. Blood flow during A-NRP was comparable, whereas oxygen consumption (VO2 ) was significantly higher in the positive outcome group after 1 h. Time courses of lactate, AST and ALT were significantly different between study groups (p < 0.001). Donors whose liver was accepted showed faster lactate clearance, a difference which was amplified by normalizing lactate clearance to oxygen delivery (DO2 ) and VO2 . Lactate clearance was correlated to transaminase levels and DO2 -normalized lactate clearance was the parameter best discriminating between study groups. CONCLUSIONS: DO2 -normalized lactate clearance may represent an element of liver viability assessment during A-NRP.

Extracellular Vesicles in Liver Transplantation: Current Evidence and Future Challenges.

Extracellular vesicles (EVs) are emerging as a promising field of research in liver disease. EVs are small, membrane-bound vesicles that contain various bioactive molecules, such as proteins, lipids, and nucleic acids and are involved in intercellular communication. They have been implicated in numerous physiological and pathological processes, including immune modulation and tissue repair, which make their use appealing in liver transplantation (LT). This review summarizes the current state of knowledge regarding the role of EVs in LT, including their potential use as biomarkers and therapeutic agents and their role in graft rejection. By providing a comprehensive insight into this emerging topic, this research lays the groundwork for the potential application of EVs in LT.

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

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

Prolonged preservation by hypothermic machine perfusion facilitates logistics in liver transplantation: A European observational cohort study.

A short period (1-2 h) of hypothermic oxygenated machine perfusion (HOPE) after static cold storage is safe and reduces ischemia-reperfusion injury-related complications after liver transplantation. Machine perfusion time is occasionally prolonged for logistical reasons, but it is unknown if prolonged HOPE is safe and compromises outcomes. We conducted a multicenter, observational cohort study of patients transplanted with a liver preserved by prolonged (≥4 h) HOPE. Postoperative biochemistry, complications, and survival were evaluated. The cohort included 93 recipients from 12 European transplant centers between 2014-2021. The most common reason to prolong HOPE was the lack of an available operating room to start the transplant procedure. Grafts underwent HOPE for a median (range) of 4:42 h (4:00-8:35 h) with a total preservation time of 10:50 h (5:50-20:50 h). Postoperative peak ALT was 675 IU/L (interquartile range 419-1378 IU/L). The incidence of postoperative complications was low, and 1-year graft and patient survival were 94% and 88%, respectively. To conclude, good outcomes are achieved after transplantation of donor livers preserved with prolonged (median 4:42 h) HOPE, leading to a total preservation time of almost 21 h. These results suggest that simple, end-ischemic HOPE may be utilized for safe extension of the preservation time to ease transplantation logistics.

Impact of MELD 30-allocation policy on liver transplant outcomes in Italy.

BACKGROUND & AIMS: In Italy, since August 2014, liver transplant (LT) candidates with model for end-stage liver disease (MELD) scores ≥30 receive national allocation priority. This multicenter cohort study aims to evaluate time on the waiting list, dropout rate, and graft survival before and after introducing the macro-area sharing policy. METHODS: A total of 4,238 patients registered from 2010 to 2018 were enrolled and categorized into an ERA-1 Group (n = 2,013; before August 2014) and an ERA-2 Group (n = 2,225; during and after August 2014). A Cox proportional hazards model was used to estimate the hazard ratio (HR) of receiving a LT or death between the two eras. The Fine-Gray model was used to estimate the HR for dropout from the waiting list and graft loss, considering death as a competing risk event. A Fine-Gray model was also used to estimate risk factors of graft loss. RESULTS: Patients with MELD ≥30 had a lower median time on the waiting list (4 vs.12 days, p <0.001) and a higher probability of being transplanted (HR 2.27; 95% CI 1.78-2.90; p = 0.001) in ERA-2 compared to ERA-1. The subgroup analysis on 3,515 LTs confirmed ERA-2 (odds ratio 0.56; 95% CI 0.46-0.68; p = 0.001) as a protective factor for better graft survival rate. The protective variables for lower dropouts on the waiting list were: ERA-2, high-volume centers, no competition centers, male recipients, and hepatocellular carcinoma. The protective variables for graft loss were high-volume center and ERA-2, while MELD ≥30 remained related to a higher risk of graft loss. CONCLUSIONS: The national MELD ≥30 priority allocation was associated with improved patient outcomes, although MELD ≥30 was associated with a higher risk of graft loss. Transplant center volumes and competition among centers may have a role in recipient prioritization and outcomes. CLINICAL TRIAL NUMBER: NCT04530240 LAY SUMMARY: Italy introduced a new policy in 2014 to give national allocation priority to patients with a model for end-stage liver disease (MELD) score ≥30 (i.e. very sick patients). This policy has led to more liver transplants, fewer dropouts, and shorter waiting times for patients with MELD ≥30. However, a higher risk of graft loss still burdens these cases. Transplant center volumes and competition among centers may have a role in recipient prioritization and outcomes.

A multicentre outcome analysis to define global benchmarks for donation after circulatory death liver transplantation.

BACKGROUND & AIMS: The concept of benchmarking is established in the field of transplant surgery; however, benchmark values for donation after circulatory death (DCD) liver transplantation are not available. Thus, we aimed to identify the best possible outcomes in DCD liver transplantation and to propose outcome reference values. METHODS: Based on 2,219 controlled DCD liver transplantations, collected from 17 centres in North America and Europe, we identified 1,012 low-risk, primary, adult liver transplantations with a laboratory MELD score of ≤20 points, receiving a DCD liver with a total donor warm ischemia time of ≤30 minutes and asystolic donor warm ischemia time of ≤15 minutes. Clinically relevant outcomes were selected and complications were reported according to the Clavien-Dindo-Grading and the comprehensive complication index (CCI). Corresponding benchmark cut-offs were based on median values of each centre, where the 75th-percentile was considered. RESULTS: Benchmark cases represented between 19.7% and 75% of DCD transplantations in participating centres. The 1-year retransplant and mortality rates were 4.5% and 8.4% in the benchmark group, respectively. Within the first year of follow-up, 51.1% of recipients developed at least 1 major complication (≥Clavien-Dindo-Grade III). Benchmark cut-offs were ≤3 days and ≤16 days for ICU and hospital stay, ≤66% for severe recipient complications (≥Grade III), ≤16.8% for ischemic cholangiopathy, and ≤38.9 CCI points 1 year after transplant. Comparisons with higher risk groups showed more complications and impaired graft survival outside the benchmark cut-offs. Organ perfusion techniques reduced the complications to values below benchmark cut-offs, despite higher graft risk. CONCLUSIONS: Despite excellent 1-year survival, morbidity in benchmark cases remains high. Benchmark cut-offs targeting morbidity parameters offer a valid tool to assess the protective value of new preservation technologies in higher risk groups and to provide a valid comparator cohort for future clinical trials. LAY SUMMARY: The best possible outcomes after liver transplantation of grafts donated after circulatory death (DCD) were defined using the concept of benchmarking. These were based on 2,219 liver transplantations following controlled DCD donation in 17 centres worldwide. Donor and recipient combinations with higher risk had significantly worse outcomes. However, the use of novel organ perfusion technology helped high-risk patients achieve similar outcomes as the benchmark cohort.

Protective Role of Tacrolimus, Deleterious Role of Age and Comorbidities in Liver Transplant Recipients With Covid-19: Results From the ELITA/ELTR Multi-center European Study.

BACKGROUND AND AIMS: Despite concerns that liver transplant (LT) recipients may be at increased risk of unfavorable outcomes from COVID-19 due the high prevalence of co-morbidities, immunosuppression and ageing, a detailed analysis of their effects in large studies is lacking. METHODS: Data from adult LT recipients with laboratory confirmed SARS-CoV2 infection were collected across Europe. All consecutive patients with symptoms were included in the analysis. RESULTS: Between March 1 and June 27, 2020, data from 243 adult symptomatic cases from 36 centers and 9 countries were collected. Thirty-nine (16%) were managed as outpatients while 204 (84%) required hospitalization including admission to the ICU (39 of 204, 19.1%). Forty-nine (20.2%) patients died after a median of 13.5 (10-23) days, respiratory failure was the major cause. After multivariable Cox regression analysis, age >70 (HR, 4.16; 95% CI, 1.78-9.73) had a negative effect and tacrolimus (TAC) use (HR, 0.55; 95% CI, 0.31-0.99) had a positive independent effect on survival. The role of co-morbidities was strongly influenced by the dominant effect of age where comorbidities increased with the increasing age of the recipients. In a second model excluding age, both diabetes (HR, 1.95; 95% CI, 1.06-3.58) and chronic kidney disease (HR, 1.97; 95% CI, 1.05-3.67) emerged as associated with death CONCLUSIONS: Twenty-five percent of patients requiring hospitalization for COVID-19 died, the risk being higher in patients older than 70 and with medical co-morbidities, such as impaired renal function and diabetes. Conversely, the use of TAC was associated with a better survival thus encouraging clinicians to keep TAC at the usual dose.

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

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

Heterogeneous indications and the need for viability assessment: An international survey on the use of machine perfusion in liver transplantation.

Although machine perfusion (MP) is being increasingly adopted in liver transplantation, indications, timing, and modality are debated. To investigate current indications for MP a web-based Google Forms survey was launched in January 2021 and addressed to 127 experts in the field, identified among first and corresponding Authors of MP literature in the last 10 years. The survey presented 10 real-life cases of donor-recipient matching, asking whether the liver would be accepted (Q1), whether MP would be used in that particular setting (Q2) and, if so, by which MP modality (Q3) and at what timing during preservation (Q4). Respondents could also comment on each case. The agreement was evaluated using Krippendorff's alpha coefficient. Answers from 39 (30.1%) participants disclosed significant heterogeneity in graft acceptance, MP indications, technique, and timing. Agreement between respondents was generally poor (Q1, α = 0.11; Q2, α = 0.14; Q3, α = 0.12, Q4, α = 0.11). Overall, respondents preferred hypothermic MP and an end-ischemic approach in 56.3% and 81.1% of cases, respectively. A total of 18 (46.2%) participants considered only one MP approach, whereas 17 (43.6%) and 3 (7.7%) considered using alternatively 2 or 3 different techniques. Of 38 comments, 17 (44.7%) were about the use of MP for graft viability assessment before implantation. This survey shows considerable variability in MP indications, emphasizing the need to identify scenarios of optimal utilization for each technique. Viability assessment emerges as a fundamental need of transplant professionals when considering the use of MP.

Highlights from the Turin international workshop on liver machine perfusion.

The 1st Turin international workshop on liver machine perfusion, which was held in Turin (Italy) on June 10th-11th, 2022, gathered more than 50 key opinion leaders and more than 220 delegates from 11 countries. The purpose of the meeting was discussing several aspects of liver machine perfusion in liver transplantation, including the state of the art, real-world clinical indications, and potential developments of this technology. We herein provide a brief summary of the evidence, perspectives and controversies presented during the meeting.

A new ex-situ machine perfusion device. A preliminary evaluation using a model of donors after circulatory death pig livers.

We herein describe a new ex-situ machine perfusion device as a "technology spotlight" using a model of donors after circulatory death liver grafts procured from slaughterhouse pigs. Fourteen pig liver grafts were included. The device allowed stable perfusion in both hypothermic (n = 6) and normothermic (n = 8) conditions and no technical failure was observed. During perfusion, perfusate and bile samples were collected to assess liver metabolism and viability. An integrated adsorption device showed efficient removal of inflammatory cytokines during treatment. This preliminary experience represents the starting point for further investigations on the potential clinical benefits of cytokines and other inflammatory mediators adsorption during machine perfusion.