Minimizing Risks of Liver Transplantation With Steatotic Donor Livers by Preferred Recipient Matching

Outcomes and risk factors for liver transplantation using steatotic grafts for hepatocellular carcinoma: a multicenter study

INTRODUCTION

A growing number of steatotic grafts have been used in liver transplantation (LT), including hepatocellular carcinoma (HCC) patients. However, the impact of steatotic grafts on the prognosis of HCC recipients remains unclear. This study aims to evaluate the impact of steatotic graft in long-term prognosis for HCC recipients and development an algorithm for minimizing the risk of these grafts.

MATERIALS AND METHODS

The clinicopathologic data of HCC patients undergoing LT from 2003 to 2022 in the United Network for Organ Sharing database was analyzed. The disease-free survival (DFS) and overall survival (OS) of recipients were compared between non-steatotic (macrosteatosis <30 %) and steatotic (macrosteatosis ≥30 %) graft groups after propensity score matching (PSM). Interaction analysis was conducted to identify factors that amplified the negative impact of steatotic grafts on DFS.

RESULTS

A total of 8345 eligible HCC patients were included. Three factors exhibited significant interaction effect with steatotic grafts: cold ischemia time ≥6h (HR = 1.447; P = 0.023), donor body mass index ≥40 (HR = 1.771; P = 0.018) and recipient with non-alcoholic fatty liver disease (HR = 1.632; P = 0.032). Hazard Associated with Macrosteatotic Liver (HAML) score was created based on these three factors. In HAML ≥1 cohort, the DFS and OS of steatotic graft group were significantly reduced compared to non-steatotic graft group. But in HAML = 0 cohort, no significant differences in DFS and OS were observed between the two groups.

CONCLUSIONS

The risk of steatotic grafts in LT for HCC could be minimized through evaluating HAML score.

Insulin-induced gene 2 alleviates ischemia-reperfusion injury in steatotic liver by inhibiting GPX4-dependent ferroptosis

Hepatic steatosis significantly elevates the vulnerability of the graft to ischemia-reperfusion (I/R) injury during liver transplantation (LT). We investigated the protective role of insulin-induced gene 2 (Insig2) in steatotic liver's I/R injury and underlying mechanisms. Employing mouse model with Insig2 knock-out or hepatocyte-specific overexpression and high-fat diets to induce steatosis, we subjected these mice to hepatic I/R injury. The primary hepatocytes isolated from steatotic liver were used in in vitro hypoxia/reoxygenation (H/R) experiment. Our integrated in vivo and in vitro approach uncovered that Insig2 deficiency exacerbated steatotic liver's damage following hepatic I/R injury, whereas its overexpression offers protection. Mechanically, integrative analysis of transcriptome, proteome, and metabolome found that Insig2 deficiency disturbed lipid metabolism and oxidative stress homeostasis, particularly inhibiting GPX4 expression to induce ferroptosis. Furthermore, chemical inhibition of ferroptosis reversed the deleterious effect of Insig2 deficiency; whereas the protective influence of Insig2 overexpression was negated by the target inhibition of GPX4, leading to an exacerbation of hepatic I/R damage. These insights underscored the potential of the Insig2-GPX4 axis as a therapeutic target, presenting a novel avenue for enhancing the resilience of steatotic liver grafts against I/R injury.

Recipient toll-like receptor 4 determines the outcome of ischemia-reperfusion injury in steatotic liver transplantation in mice

Toll-like receptor 4 (TLR4) plays a crucial role in ischemia-reperfusion injury (IRI) after liver transplantation (LT). However, the role of TLR4 in the context of steatotic grafts remains unclear. In this study, we developed a mouse model to explore IRI mechanisms in steatotic LT using TLR4 knockout mice as recipients. We successfully transplanted steatotic grafts with approximately 35% macrosteatosis and 5 hours of cold storage. Compared to normal LT, steatotic LT resulted in significantly higher serum level of alanine aminotransferase and high mobility group box 1 (HMGB1), higher transcriptional expression of inflammatory markers (C-X-C motif chemokine ligand 2, caspase-1, and caspase-11), and increased infiltration of CD11b-positive cells, correlating with lower survival. Serum HMGB1 and cleaved caspase-3 activation peaked earlier than serum alanine aminotransferase, with cold-stored steatotic grafts releasing more HMGB1. Notably, TLR4 knockout recipients demonstrated improved survival, attenuated inflammatory response, and reduced apoptosis. These findings suggest that TLR4 deficiency in recipients ameliorates IRI in steatotic LT, highlighting the importance of recipient immune modulation in mitigating steatotic graft injury.

Effects of Desflurane versus sevoflurane on graft outcome of patients with cirrhosis receiving steatotic liver graft in deceased donor liver transplantation

STUDY OBJECTIVE

This study aimed to analyze the effects of two volatile anesthetic agents, desflurane and sevoflurane, on graft outcomes in patients undergoing deceased donor liver transplantation (DDLT) for cirrhosis, with a specific focus on fatty grafts.

DESIGN

A retrospective observational study.

SETTING

A tertiary hospital (Severance Hospital, Korea).

PATIENTS

This study included 151 patients with liver cirrhosis who underwent DDLT for cirrhosis between January 2006 and December 2022.

INTERVENTIONS

Patients were grouped according to maintenance anesthesia received (desflurane or sevoflurane), the model for end-stage liver disease (MELD) score, and macrovesicular steatosis (MVS) of the liver graft.

MEASUREMENTS

Survival curves were constructed from the date of surgery to graft failure or death. After propensity score matching (PSM), Cox regression analysis was used to compare hazards ratios (HR) for 5-year graft and overall survival. Subgroup analyses were performed for the MELD score and MVS of the liver graft. Incidences of 1-month acute rejection and early allograft dysfunction (EAD) were also compared between the two groups.

MAIN RESULTS

Among 151 eligible patients, 49 patients remained in each group after PSM, with 14 (28.6 %) graft failures and deaths occurring in each group. In matched analysis, sevoflurane showed poorer 5-year graft and overall survival compared to desflurane in recipients of graft with ≥10 % MVS, and this trend was significant in patients with MELD score of ≥35. In Cox regression model, compared to desflurane sevoflurane showed a propensity score-matched HR of 5.8 (95 % CI, 1.13-30.50 for both 5-year graft and overall survival. Additionally, sevoflurane showed an increased risk of 1-month acute rejection; however, no difference was observed for EAD.

CONCLUSIONS

Sevoflurane as a maintenance agent during DDLT in recipients with high MELD scores and fatty grafts may be associated with poorer outcomes compared to desflurane.

Graft Steatosis and Donor Diabetes Mellitus Additively Impact on Recipient Outcomes After Liver Transplantation-A European Registry Study

BACKGROUND AND AIMS

Biopsy-proven severe graft steatosis is associated with adverse outcomes after liver transplantation. The concomitant presence of metabolic risk factors might further increase this risk. We studied the association between graft steatosis and metabolic risk factors in the donor, with recipient outcomes after liver transplantation.

METHODS

We analyzed data from all consecutive first adult full-graft donation after brain death (DBD) liver transplantations performed in the Eurotransplant region between 2010 and 2020. The presence of graft steatosis and metabolic risk factors was assessed through a review of donor (imaging) reports, and associations with recipient retransplantation-free survival were studied through survival analyses.

RESULTS

Of 12 174 transplantations, graft steatosis was detected in 2689 (22.1%), and donor diabetes mellitus (DM), hypertension, and dyslipidemia were present in 1245 (10.2%), 5056 (41.5%), and 524 (4.3%). In multivariable Cox regression analysis, graft steatosis (adjusted HR [aHR] 1.197, p < 0.001) and donor DM (aHR 1.157, p = 0.004) were independently associated with impaired retransplantation-free survival. Graft steatosis and donor DM conferred an additive risk of retransplantation or death (DM alone, aHR: 1.156 [p = 0.0185]; steatosis alone, aHR: 1.200 [p < 0.001]; both steatosis and DM, aHR: 1.381 [p < 0.001]). Findings were consistent in sensitivity analyses focusing on retransplantation-free survival within 7 days.

CONCLUSIONS

Graft steatosis and donor diabetes mellitus additively increase the risk of retransplantation or death in adult DBD liver transplantation. Future studies should focus on methods to assess and improve the quality of these high-risk grafts. Until such time, caution should be exercised when considering these grafts for transplantation.

Overcoming the hurdles of steatotic grafts in liver transplantation: Insights into survival and prognostic factors

With increasing metabolic dysfunction-associated steatotic liver disease, the use of steatotic grafts in liver transplantation (LT) and their impact on postoperative graft survival (GS) needs further exploration. Analyzing adult LT recipient data (2002-2022) from the United Network for Organ Sharing database, outcomes of LT using steatotic (≥30% macrosteatosis) and nonsteatotic donor livers, donors after circulatory death, and standard-risk older donors (age 45-50) were compared. GS predictors were evaluated using Kaplan-Meier and Cox regression analyses. Of the 35,345 LT donors, 8.9% (3,155) were fatty livers. The initial 30-day postoperative period revealed significant challenges with fatty livers, demonstrating inferior GS. However, the GS discrepancy between fatty and nonfatty livers subsided over time ( p = 0.10 at 5 y). Long-term GS outcomes showed comparable or even superior results in fatty livers relative to nonsteatotic livers, conditional on surviving the initial 90 postoperative days ( p = 0.90 at 1 y) or 1 year ( p = 0.03 at 5 y). In the multivariable Cox regression analysis, the high body surface area (BSA) ratio (≥1.1) (HR 1.42, p = 0.02), calculated as donor BSA divided by recipient BSA, long cold ischemic time (≥6.5 h) (HR 1.72, p < 0.01), and recipient medical condition (intensive care unit hospitalization) (HR 2.53, p < 0.01) emerged as significant adverse prognostic factors. Young (<40 y) fatty donors showed a high BSA ratio, diabetes, and intensive care unit hospitalization as significant indicators of a worse prognosis ( p < 0.01). Our study emphasizes the initial postoperative 30-day survival challenge in LT using fatty livers. However, with careful donor-recipient matching, for example, avoiding the use of steatotic donors with long cold ischemic time and high BSA ratios for recipients in the intensive care unit, it is possible to enhance immediate GS, and in a longer time, outcomes comparable to those using nonfatty livers, donors after circulatory death livers, or standard-risk older donors can be anticipated. These novel insights into decision-making criteria for steatotic liver use provide invaluable guidance for clinicians.

Current Understanding of Marginal Grafts in Liver Transplantation

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

Deep Learning-Based Survival Analysis for Receiving a Steatotic Donor Liver Versus Waiting for a Standard Liver

BACKGROUND

An emerging strategy to expand the donor pool is the use of a steatotic donor liver (SDLs; ≥ 30% macrosteatosis on biopsy). With the obesity epidemic and prevalence of nonalcoholic fatty liver disease, SDLs have been reported in 59% of all deceased donors. Many potential candidates need to decide whether to accept an SDL offer or remain on the waitlist for a nonsteatotic donor liver (non-SDL). The objective of this study was to compare the survival of accepting an SDL vs using a non-SDL after waiting various times.

METHODS

Using data from the United States' organ procurement and transplantation network, deep survival learning predictive models were built to compare post-decision survival after accepting an SDL vs waiting for a non-SDL. The comparison subjects contain simulated 20,000 different scenarios of a candidate either accepting an SDL immediately or receiving a non-SDL after waiting various times. The research variables were selected using the LASSO-Cox and Random Survival Forest (RSF) models. The Cox proportional hazards and RSF models were also comparatively included for survival prediction. In addition, personalized survival curves for randomly selected candidates were generated.

RESULT

Deep survival learning outperformed Cox proportional hazards and RSF in predicting the survival of liver transplants. Among the simulations, 25% to 30% of scenarios demonstrated a higher 3-year survival post-decision for candidates accepting an SDL than waiting and receiving a non-SDL. The difference was only 1.43% in 3-year survival post-decision between accepting an SDL and waiting 260 days (mean waitlist time) for a non-SDL. As the number of days on the waitlist increases, the difference in survival between accepting SDLs and waiting for non-SDLs decreases.

CONCLUSIONS

Appropriately used SDLs could expand the donor pool and relieve the candidates' unmet need for donor livers, which presents long-term survival benefits for recipients.

Beyond donation to organ utilization in the USA

PURPOSE OF REVIEW

The deceased donor organ pool has broadened beyond young, otherwise healthy head trauma victims. But an abundance of donated organs only benefits patients if they are accepted, expeditiously transported and actually transplanted. This review focuses on postdonation challenges and opportunities to increase the number of transplants through improved organ utilization.

RECENT FINDINGS

We build upon recently proposed changes in terminology for measuring organ utilization. Among organs recovered for transplant, the nonuse rate (NUR REC ) has risen above 25% for kidneys and pancreata. Among donors, the nonuse rate (NUR DON ) has risen to 40% for livers and exceeds 70% for thoracic organs. Programme-level variation in offer acceptance rates vastly exceeds variation in the traditional, 1-year survival benchmark. Key opportunities to boost utilization include donation after circulatory death and hepatitis C virus (HCV)+ organs; acute kidney injury and suboptimal biopsy kidneys; older and steatotic livers.

SUMMARY

Underutilization of less-than-ideal, yet transplant-worthy organs remains an obstacle to maximizing the impact of the U.S. transplant system. The increased risk of inferior posttransplant outcomes must always be weighed against the risks of remaining on the waitlist. Advanced perfusion technologies; tuning allocation systems for placement efficiency; and data-driven clinical decision support have the potential to increase utilization of medically complex organs.

Impact of Donor Liver Macrovesicular Steatosis on Deceased Donor Yield and Posttransplant Outcome

BACKGROUND

The Scientific Registry of Transplant Recipients (SRTR) had not traditionally considered biopsy results in risk-adjustment models, yet biopsy results may influence outcomes and thus decisions regarding organ acceptance.

METHODS

Using SRTR data, which includes data on all donors, waitlisted candidates, and transplant recipients in the United States, we assessed (1) the impact of macrovesicular steatosis on deceased donor yield (defined as number of livers transplanted per donor) and 1-y posttransplant graft failure and (2) the effect of incorporating this variable into existing SRTR risk-adjustment models.

RESULTS

There were 21 559 donors with any recovered organ and 17 801 liver transplant recipients included for analysis. Increasing levels of macrovesicular steatosis on donor liver biopsy predicted lower organ yield: ≥31% macrovesicular steatosis on liver biopsy was associated with 87% to 95% lower odds of utilization, with 55% of these livers being discarded. The hazard ratio for graft failure with these livers was 1.53, compared with those with no pretransplant liver biopsy and 0% to 10% steatosis. There was minimal change on organ procurement organization-specific deceased donor yield or program-specific posttransplant outcome assessments when macrovesicular steatosis was added to the risk-adjustment models.

CONCLUSIONS

Donor livers with macrovesicular steatosis are disproportionately not transplanted relative to their risk for graft failure. To avoid undue risk aversion, SRTR now accounts for macrovesicular steatosis in the SRTR risk-adjustment models to help facilitate use of these higher-risk organs. Increased recognition of this variable may also encourage further efforts to standardize the reporting of liver biopsy results.

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.

A Novel Digital Algorithm for Identifying Liver Steatosis Using Smartphone-Captured Images

Access to lifesaving liver transplantation is limited by a severe organ shortage. One factor contributing to the shortage is the high rate of discard in livers with histologic steatosis. Livers with <30% macrosteatosis are generally considered safe for transplant. However, histologic assessment of steatosis by a pathologist remains subjective and is often limited by image quality. Here, we address this bottleneck by creating an automated digital algorithm for calculating histologic steatosis using only images of liver biopsy histology obtained with a smartphone.

Outcomes after Liver Transplantation with Steatotic Grafts: Redefining Acceptable Cutoffs for Steatotic Grafts

BACKGROUND

Graft macrosteatosis can predispose to a higher risk of graft loss so we sought to redefine acceptable cutoffs for graft steatosis.

METHODS

Data of 26,103 donors who underwent liver transplantation (LT) between January 2004 and December 2018 from the UNOS-STAR database were utilized. A high-risk steatotic (HRS) graft and a low-risk steatotic (LRS) graft were defined as ≥20% and <20% macrosteatosis, respectively. High-risk steatotic grafts were further classified as grafts with 20-29% (G1S grafts), 30-39% (G2S grafts), and ≥40% steatosis (G3S grafts). Outcomes between groups were compared.

RESULTS

LRS grafts had excellent graft (93.3 and 87.7%) and overall survival (95.4 and 90.5%) at 90 days and 1 year. Compared to LRS grafts, G1S, G2S, and G3S grafts had worse graft and overall survival at 90 days and 1-year (p <0.001). There was no difference in graft or overall survival of G1S or G3S grafts compared to G2S grafts until after adjustment in which G3S grafts were found to be associated with an increased risk of graft loss-aHR 1.27 (1.03-1.57), p = 0.02.

DISCUSSION

Liver grafts can be categorized into three categories: (1) <20% or "very low risk", (2) 20-39% or "low-to-moderate risk", and usually acceptable, and (3) ≥40% steatosis or "moderate-to-high risk".

HOW TO CITE THIS ARTICLE

Da BL, Satiya J, Heda RP, et al. Outcomes after Liver Transplantation with Steatotic Grafts: Redefining Acceptable Cutoffs for Steatotic Grafts. Euroasian J Hepato-Gastroenterol 2022;12(Suppl 1):S5-S14.

Impact of living donor liver with steatosis and idiopathic portal inflammation on clinical outcomes in pediatric liver transplantation: Beijing experience

BACKGROUND

To evaluate the impact of steatosis and/or idiopathic portal inflammation (IPI) in living donor livers on recipients' clinical outcomes.

METHODS

We assessed 305 qualified donor liver samples from June 2013 to December 2018. Donors and recipients' clinical characteristics, including follow-up data were retrieved. The graft and overall survival with/without steatosis or portal inflammation were compared by Kaplan-Meier analysis.

RESULTS

For living donors, the medium age of was 31.2 (28, 35.8) years old; liver histopathology showed macrovesicular steatosis: 0-5% 264/305 (86.6%) and 5-30% 41/305 (13.4%), IPI: no 220/305 (72.1%) and mild 85/305 (27.9%). For recipients, the medium age was 1.0 (0.6, 1.5) years old; the median pediatric-end-stage-liver-disease score was 16 (5.0, 26.0) and medium follow-up time was 32.8 (24.8, 52.0) months. Biliary atresia (69.5%) was the main indication for liver transplantation (LT).

CONCLUSIONS

The presence of steatosis and portal inflammation of the donor liver did not impact the clinical outcomes including transaminase or bilirubin normalization, short-/long-term complications and recipients' survival. However, recipients with high pediatric-end-stage-liver-disease score (>16) receiving donor liver with portal inflammation, but not steatosis, had trend negative effect on recipients' survival. In conclusion, donor livers with mild steatosis and portal inflammation were qualified for pediatric living donor LT. However, donor liver with mild portal inflammation would better not be allocated to recipients with high pediatric-end-stage-liver-disease score. This study provided new evidence in pediatric living donor liver allocation.

Evaluating Outcomes Related to Donor and Recipient Metabolic Environment: Macrosteatotic Allografts and Nonalcoholic Steatohepatitis

The increasing prevalence of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) affects both recipient and donor populations in liver transplantation. Presently, it is unclear whether transplantation of macrosteatotic allografts is affected by the metabolic milieu of liver transplant recipients. This study investigates fatty liver disease at the intersection of donor and recipient. A retrospective review of the Organ Procurement and Transplantation database identified 5167 NASH and 26,289 non-NASH transplant recipients who received transplants from January 1, 2004, to June 12, 2020. A total of 12,569 donors had allografts with no macrosteatosis (<5%), 16,140 had mild macrosteatosis (5%-29%), and 2747 had moderate to severe macrosteatosis (≥30%). Comparing recipients with NASH to propensity score-matched (PSM) recipients without NASH demonstrated noninferior graft and patient survival up to 10 years in patients with NASH. Similar trends were observed in subgroup analyses of transplants within each strata of allograft macrosteatosis. Assessing allograft macrosteatosis specifically in the NASH population demonstrated that allografts with ≥30% macrosteatosis were associated with reduced early graft survival (30 days, 93.32% versus 96.54% [P = 0.02]; 1 year, 84.53% versus 88.99% [P = 0.05]) compared with PSM grafts with <30% macrosteatosis. Long-term graft survival at 5 and 10 years, however, was similar. The use of carefully selected macrosteatotic allografts can be successful in both recipients with NASH and recipients without NASH. The metabolic environment of patients with NASH does not appear to adversely affect outcomes with regard to the allograft when controlled for numerous confounders. It is, however, important to remain cognizant of the potential for high-risk macrosteatotic allografts to negatively affect outcomes.

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

Supplemental Digital Content is available in the text.

Background.

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

Methods.

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

Results.

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

Conclusions.

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

A proof of concept study on real-time LiMAx CYP1A2 liver function assessment of donor grafts during normothermic machine perfusion

No single reliable parameter exists to assess liver graft function of extended criteria donors during ex-vivo normothermic machine perfusion (NMP). The liver maximum capacity (LiMAx) test is a clinically validated cytochromal breath test, measuring liver function based on 13CO2 production. As an innovative concept, we aimed to integrate the LiMAx breath test with NMP to assess organ function. Eleven human livers were perfused using NMP. After one hour of stabilization, LiMAx testing was performed. Injury markers (ALT, AST, miR-122, FMN, and Suzuki-score) and lactate clearance were measured and related to LiMAx values. LiMAx values ranged between 111 and 1838 µg/kg/h, and performing consecutive LiMAx tests during longer NMP was feasible. No correlation was found between LiMAx value and miR-122 and FMN levels in the perfusate. However, a significant inverse correlation was found between LiMAx value and histological injury (Suzuki-score, R = − 0.874, P < 0.001), AST (R = − 0.812, P = 0.004) and ALT (R = − 0.687, P = 0.028). Furthermore, a significant correlation was found with lactate clearance (R = 0.683, P = 0.043). We demonstrate, as proof of principle, that liver function during NMP can be quantified using the LiMAx test, illustrating a positive correlation with traditional injury markers. This new breath-test application separates livers with adequate cytochromal liver function from inadequate ones and may support decision-making in the safe utilization of extended criteria donor grafts.

Pilot study of a noninvasive real-time optical backscatter probe in liver transplantation

Transplantation of severely steatotic donor livers is associated with early allograft dysfunction and poorer graft survival. Histology remains the gold standard diagnostic of donor steatosis despite the lack of consensus definition and its subjective nature. In this prospective observational study of liver transplant patients, we demonstrate the feasibility of using a handheld optical backscatter probe to assess the degree of hepatic steatosis and correlate the backscatter readings with clinical outcomes. The probe is placed on the surface of the liver and emits red and near infrared light from the tip of the device and measures the amount of backscatter of light from liver tissue via two photodiodes. Measurement of optical backscatter (Mantel-Cox P < 0.0001) and histopathological scoring of macrovesicular steatosis (Mantel-Cox P = 0.046) were predictive of 5-year graft survival. Recipients with early allograft dysfunction defined according to both Olthoff (P = 0.0067) and MEAF score (P = 0.0097) had significantly higher backscatter levels from the donor organ. Backscatter was predictive of graft loss (AUC 0.75, P = 0.0045). This study demonstrates the feasibility of real-time measurement of optical backscatter in donor livers. Early results indicate readings correlate with steatosis and may give insight to graft outcomes such as early allograft dysfunction and graft loss.

Fatty liver: The metabolic syndrome increases major hepatectomy mortality

BACKGROUND

As the obesity epidemic worsens, the prevalence of fatty liver disease has increased. However, minimal data exist on the impact of combined fatty liver and metabolic syndrome on hepatectomy outcomes. Therefore, the aim of this analysis is to measure the outcomes of patients who do and do not have a fatty liver undergoing hepatectomy in the presence and absence of the metabolic syndrome.

METHODS

Patients with fatty and normal livers undergoing major hepatectomy (≥3 segments) were identified in the 2014 to 2018 American College of Surgeon National Surgical Quality Improvement Program database. Patients undergoing partial hepatectomy and those with missing liver texture data were excluded. Propensity matching was used and adjusted for multiple variables. A subgroup analysis stratified by the metabolic syndrome (body mass index ≥30 kg/m², hypertension and diabetes) was performed. Demographics and outcomes were compared by χ² and Mann-Whitney tests.

RESULTS

Of 2,927 hepatectomies, 30% of patients (N = 863) had a fatty liver. The median body mass index was 28.6, and the metabolic syndrome was present in 6.3% of patients (N = 184). After propensity matching, 863 patients with fatty and 863 with normal livers were compared. Multiple outcomes were significantly worse in patients with fatty livers (P <.05), including serious morbidity (32% vs 24%), postoperative invasive biliary procedures (15% vs 10%), organ space infections (11% vs 7.8%), and pulmonary complications. Patients with fatty livers and the metabolic syndrome had significantly increased postoperative cardiac arrests, pulmonary embolisms, and mortality (P < .05).

CONCLUSION

Fatty liver disease is associated with significantly worse outcomes after major hepatectomy. The metabolic syndrome confers an increased risk of postoperative mortality.