Mild hepatic macrovesicular steatosis may be a risk factor for hyperbilirubinaemia in living liver donors following right hepatectomy

Development and validation of MRI-PDFF cutoffs for living liver donor eligibility assessment

Hepatic steatosis (HS) criteria for living donor liver transplantation (LDLT) donor eligibility should be based on large droplet fat as per Banff consensus recommendations. We aimed to establish magnetic resonance imaging proton density fat fraction cutoffs for HS assessment in potential LDLT donors. This retrospective study included consecutive potential LDLT donors who underwent MRI and liver biopsy between 2013 and 2023 at 2 tertiary institutions, each as development (n = 3062; 2015 men; median [IQR] age of 32 [25-38] y) and external validation (n = 472; 287 men; 35 [26-44] y) data sets. Proton density fat fraction (PDFF) was measured using dedicated MRI sequences. Histologic HS, defined as a large droplet fat fraction, was used as the reference standard. Dual PDFF cutoffs aimed at 95% sensitivity or 95% specificity, for diagnosing histologic HS of ≥10%, ≥20%, ≥30%, and ≥40%, were determined in the development data set using 10-fold cross-validation. The cutoffs were then validated in the external validation data set. The equation for estimating histologic HS from PDFF was also derived using linear regression. The PDFF cutoffs for histologic HS of ≥10%, ≥20%, ≥30%, and ≥40%, targeting 95% sensitivity, were 3.7%, 5.5%, 8.0%, and 10.0%, respectively. External validation demonstrated high sensitivities ≥97.9% with specificities ranging from 60.9% to 95.1%. The PDFF cutoffs targeting 95% specificity were 6.3%, 8.0%, 9.1%, and 10.1%, respectively. External validation rendered high specificities ranging from 88.5% to 95.3%, with sensitivities ranging from 76.6% to 100%. For diagnosing histologic HS ≥30%, which is the most prevalently used threshold for LDLT donor eligibility assessment, the PDFF cutoffs achieved sensitivities and specificities of over 90%. The equation of (Histologic HS = -2.95 + 1.93 × PDFF) was derived.

Safety of right liver donation after improving steatosis through weight loss in living donors: a retrospective study

BACKGROUND

Living donor liver transplantation using hepatic steatosis-improved grafts mitigates donor shortage. Herein, we aimed to evaluate the safety and feasibility of right-lobe adult-to-adult living donor liver transplantation using grafts improved through donor weight loss.

METHODS

In this retrospective study conducted in a single institution in the Republic of Korea, we reviewed the medical records of living liver donors who lost ≥ 10% of their body weight to improve steatosis before right lobe donation between January 2015 and December 2020. Overall, 1040 right-lobe donors were included, with 150 and 890 donors in the weight loss and control (non-steatosis) groups, respectively.

RESULTS

We performed 1:1 individual matching using the greedy matching method, by which 124 patients were included in each group. The median period from the date of the first visit to donation was 113 (interquartile range: 78-184) days in the weight loss group. As body weight changed from 82.8 ± 13.7 kg to 70.8 ± 11.8 kg (p < 0.0001), body mass index also improved from 27.8 ± 3.9 kg/m2 to 23.8 ± 3.1 kg/m2 (p < 0.0001). No significant between-group differences existed in the postoperative laboratory data for living donors and recipients. The incidence of postoperative complications in donors was comparable between the groups (control group, 9.7%; weight loss group, 13.7%; p = 0.3185). The graft and recipient survival rates were comparable between the groups (p = 1.000).

CONCLUSION

Weight loss through diet and exercise significantly could improve hepatic steatosis in living donor candidates for liver transplantation, with the surgical outcomes in recipients and donors being equivalent to those in recipients and non-steatotic donors.

Outcomes and Risk Factors for Liver Transplantation Using Graft-to-Recipient Weight Ratio Less Than 0.8 Graft From Living Donors: Multicentric Cohort Study

OBJECTIVE

To compare graft survival after living donor liver transplantation (LDLT) in patients receiving graft-to-recipient weight ratio (GRWR) <0.8 versus GRWR≥0.8 grafts and identify risk factors for graft loss using GRWR<0.8 grafts.

BACKGROUND

Favorable outcomes after LDLT using GRWR<0.8 grafts were recently reported; however, these results have not been validated using multicenter data.

METHODS

This multicentric cohort study included 3450 LDLT patients. Graft survival was compared between 1:3 propensity score-matched groups and evaluated using various Cox models in the entire population. Risk factors for graft loss with GRWR<0.8 versus GRWR≥0.8 grafts were explored within various subgroups using interaction analyses, and outcomes were stratified according to the number of risk factors.

RESULTS

In total, 368 patients (10.7%) received GRWR<0.8 grafts (GRWR<0.8 group), whereas 3082 (89.3%) received GRWR≥0.8 grafts (GRWR≥0.8 group). The 5-year graft survival rate was significantly lower with GRWR<0.8 grafts than with GRWR≥0.8 grafts (85.2% vs 90.1%, P =0.013). Adjusted hazard ratio for graft loss using GRWR<0.8 grafts in the entire population was 1.66 (95% CI: 1.17-2.35, P =0.004). Risk factors exhibiting significant interactions with GRWR<0.8 for graft survival were age ≥60 years, Model for End-stage Liver Disease score ≥15, and male donor. When ≥2 risk factors were present, GRWR<0.8 grafts showed a higher risk of graft loss compared with GRWR≥0.8 graft in LDLT (hazard ratio 2.98, 95% CI: 1.79-4.88, P <0.001).

CONCLUSIONS

GRWR<0.8 graft showed inferior graft survival than controls (85.2% vs 90.1%), especially when ≥2 risk factors for graft loss (among age 60 years or above, Model for End-stage Liver Disease score ≥15, or male donor) were present.

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Association between nonalcoholic fatty liver disease and increased glucose-to-albumin ratio in adults without diabetes

Background

Nonalcoholic fatty liver disease (NAFLD) affects approximately 30% of individuals globally. Both serum glucose and albumin were demonstrated to be potential markers for the development of NAFLD. We hypothesized that the risk of NAFLD may be proportional to the glucose-to-albumin ratio (GAR).

Methods

Based on information from the National Health and Nutrition Examination Survey (NHANES) 1999-2018, it was determined that GAR was associated with an increased risk of NAFLD and liver fibrosis utilizing weighted multivariable logistic regression. Participants with a fatty liver index (FLI) over 60 were identified with NAFLD, and those with an NAFLD fibrosis score (NFS) >0.676 with evidence of NAFLD were labeled with advanced hepatic fibrosis (AHF). The liver biopsy was utilized to verify the relationship between GAR and FLD in our center cohort. Mendelian randomization analysis investigated the genetic relationship between GAR and NAFLD.

Results

Of 15,534 eligible participants, 36.4% of participants were identified as NAFLD without AHF. GAR was positively correlated with the probability of NAFLD following full adjustment for possible variables (OR = 1.53, 95% CI: 1.39-1.67). It was confirmed that patients with NAFLD and AHF had an inferior prognosis. The relationship between GAR and NFS was favorable (R = 0.46, P< 0.0001), and NAFLD patients with a higher GAR tended to develop poor survival. In our center cohort, the association between GAR and NAFLD was verified.

Conclusion

Among participants without diabetes, greater GAR was linked to higher risks of NAFLD. In addition, NAFLD patients with higher GAR tended to develop liver fibrosis and adverse outcomes.

Vibration Controlled Transient Elastography to Evaluate Steatosis in Candidate Living Donors for Liver Transplantation

BACKGROUND

The ability of vibration controlled transient elastography (VCTE) to reliably exclude significant steatosis in living donor candidates could obviate the need for invasive liver biopsies, expedite the donor approval process, and reduce recipient wait time. We therefore aimed to determine whether VCTE controlled attenuation parameter (CAP) could be used to detect steatosis in potential living donors.

METHODS

Living donor candidates who presented for evaluation between 2016 and 2019 underwent standard donor workup, VCTE, and liver biopsy if indicated. CAP scores were compared with MRI-Fat Fraction and, when available, histologic fat fraction from liver biopsy. Receiver operating characteristic curves were used to identify cutoffs with appropriate sensitivity and specificity for screening. Statistical analysis was conducted using R (version 3.6.0).

RESULTS

Seventy-nine candidate living donors presented during the study period, of whom 71 were included in the final analysis and of whom 20 underwent liver biopsy. There was a positive correlation between MRI-Fat Fraction and CAP scores with an observed Spearman correlation coefficient of 0.424 ( P < 0.01). A CAP score of 271.5 dB/m or less was determined to have 89.8% sensitivity and 75% specificity for detecting <5% steatosis on MRI. The correlation between CAP and steatosis of available histologic samples had a Pearson correlation coefficient of 0.603 ( P = 0.005). A CAP cutoff of 276.0 dB/m demonstrated 66.7% sensitivity and 85.7% specificity for detecting <15% histopathologic steatosis and positive and negative predictive values of 71.5% and 82.7%, respectively.

CONCLUSIONS

VCTE can be integrated into living donor evaluation to accurately screen for hepatic steatosis.

Is there a role for preoperative liver reducing diet in hepatectomy? A systematic review

PURPOSE

Preoperative very low-calorie diets (VLCDs) have been shown to reduce liver volume, reduce the risk of liver injury and improve safety during bariatric surgery. Hepatic steatosis (HS) has been associated with poorer outcomes in liver resection. VLCD can be used to improve HS. We aim to explore if preoperative VLCD could improve outcomes for patients with HS undergoing liver resection.

METHODS

We performed a systematic review of MEDLINE, EMBASE, PubMed and Cochrane databases. Studies were included if they were full-text articles investigating the effect of a preoperative dietary intervention in patients undergoing liver resection on intra-operative and post-operative outcomes. The last search was performed on 11 Jun 2020. Evidence quality was assessed by "GRADE". A narrative review was undertaken.

RESULTS

Five studies were found: one RCT and four cohort studies including 133 patients in intervention groups and 181 controls. Three used diet-only strategies and two diet and exercise strategies with varying time courses and monitoring. The quality of evidence assessed by GRADE was "high" for the RCT and "low" for the four cohort studies. Steatosis objectively improved in three studies, with evidence of reduced liver volume and increased attenuation on imaging in one. All studies showed a reduction in body weight and body mass index (BMI). Intra-operative blood loss was decreased following a diet-only intervention in two studies, and liver mobility improved in one. No difference was found in morbidity, mortality or hospital length of stay between intervention and control groups.

CONCLUSIONS

There is evidence of poorer outcomes in liver resection patients with existing HS. There is an expected role for a preoperative VLCD to optimise these patients for surgery. Existing publications support this, but diet interventions and outcome measures are inconsistent, and patient numbers are small. There is scope for a well-designed, multi-centre randomised trial to investigate this further.

Validation of Accuracy of Non-Invasive Imaging Methods (Magnetic Resonance Imaging (MRI) Fat Fraction Calculation and Computed Tomography (CT) Liver Attenuation Index) for Hepatic Graft Fat Quantification in Living Liver Transplant Donors

BACKGROUND Diagnosis of significant hepatic graft steatosis remains vital for success of any transplant program as it has an impact on donor morbidity and recipient survival. Even histopathological quantification faces limitations. The present study compared the diagnostic accuracy of CT-LAI and MRI fat fraction imaging with histopathological analysis for donor graft parenchymal fat quantification. MATERIAL AND METHODS CT-LAI and MR-FF values and histopathological fat quantification results of 273 patients were identified from electronic records of the author's institutes from September 2015 to April 2020. Data analysis was done using SPSS version 21.0. RESULTS Most participants were young with nearly equal sex distribution and significant number of overweight and obese patients. Moderate agreement and significant positive correlation were found between MR fat fraction (%) and biopsy-macrosteatosis (%). Diagnostic accuracy and negative predictive value of MRI for fat fraction calculation was high (95.24% and 98.07% for fat fraction of 10% threshold, respectively), and it further improved for fat fraction threshold of 15%. CONCLUSIONS MRI-based fat quantification calculation displayed near-perfect negative predictive values and very high diagnostic accuracy, suggesting that it can obviate the need for biopsy in patients with graft fat percentage <10% on MRI.

Protective effect of ischemic postconditioning on ischemia reperfusion injury in steatotic rat livers

Background

Hepatic steatosis creates a significant risk of liver resection and transplantation and is extremely susceptible to ischemia/reperfusion (I/R) injury. Ischemic postconditioning (IPostC) has been shown to attenuate I/R injury in normal livers; however, its role in steatotic livers remains unknown. The current study sought to explore whether IPostC could attenuate normothermic I/R injury in rats with steatotic livers and to investigate potential protective measures.

Methods

Hepatic steatosis was triggered in Wistar rats fed high-fat diets. The role of IPostC was detected in normal and steatotic livers with 30 min of ischemia and 6 h of reperfusion. Blood and liver tissues were collected to assess hepatocyte damage, lipid peroxidation, inflammatory factors, neutrophil accumulation, and adenosine triphosphate (ATP) content.

Results

Compared to normal livers, steatotic livers were more susceptible to I/R damage, as evidenced by incremental concentrations of liver enzymes in the blood and more severe pathological changes in the liver. Hepatic I/R injury was significantly reduced by IPostC in both normal and steatotic livers. We further found that endogenous protective measures moderated lipid peroxidation, inflammatory cytokine expression and neutrophil accumulation, and reduced follow-up hepatic injury. The ATP content of steatotic livers was also significantly lower than that of Normal livers before and after I/R injury. IPostC greatly preserved the ATP content of normal and steatotic livers with I/R injury.

Conclusions

IPostC appears to provide important protection against hepatic I/R injury in normal and steatotic livers under normothermic conditions. These data have important clinical implications for liver surgery and transplantation.

Safe use of right lobe living donor livers with moderate steatosis in adult-to-adult living donor liver transplantation: a retrospective study

Hepatic steatosis (HS) beyond a certain degree can jeopardize living donor (LD) safety, particularly in right lobe (RL) donors, making it a major obstacle for donor pool expansion in adult-to-adult living donor liver transplantation (ALDLT). From July 2004 to June 2016, 58 LDs donated their RLs despite having moderate HS (30%-50% steatosis) determined by intraoperative biopsy at a single center. We performed greedy matching to compare the outcomes of the donors and recipients of this group with those of LDs with no HS. The mean left lobe (LL) HS value in the 58 cases was 20.9 ± 12.4%, which was significantly lower than the mean RL HS value (38.8 ± 6.7%, P < 0.001). The mean ratio of the remnant LL to the total liver volume was 37.8 ± 2.2. No differences were observed in the postoperative liver function and donor and recipient morbidity and mortality rates. The liver regeneration rates in recipients and donors at 1 month, 6 months, and 1 year postoperatively did not differ significantly. The patient and graft survival rates of the recipients showed no differences. The use of well-selected RL grafts with moderate steatosis does not impair graft function, recipient outcomes, or donor safety.

Lifestyle Modification Leads to Spatially Variable Reduction in Hepatic Steatosis in Potential Living Liver Donors

The spatial variability of hepatic fat reduction in potential living liver donors with hepatic steatosis (HS) who undergo lifestyle modification has not been investigated. Here, we aimed to examine the intrasegmental and intersegmental variability of changes in liver attenuation on computed tomography (CT) in potential living liver donors with HS after diet modification and exercise. A total of 87 living liver donor candidates (30.5 ± 7.0 years; 74 males) with biopsy-proven macrovesicular fat (MaF) ≥10% were included. All underwent diet modification and exercise to improve HS, baseline and follow-up unenhanced CT scans, and liver biopsies. Attenuation and its variability (mean and standard deviation, respectively, in Hounsfield units) in segmental, lobar, superficial, deep, and whole areas of the liver were measured across 32 different regions of interest on both baseline and follow-up CT. At baseline, the right lobe and superficial areas of liver showed significantly lower and more variable attenuation than left lobe and deep areas. Greater variability was noted in patients with more severe HS. Mean interval changes in liver attenuation and variability before and after diet modification and exercise were 13.7 (range, -10.6 to 46.2) and 4.7 (1.6-10.6), respectively. The mean interval change in liver attenuation was significantly higher in the right lobe than in the left (14.7 versus 12.7; P < 0.001), and in superficial areas than in deep areas (14.0 versus 13.4; P = 0.02). Greater variability and larger interval changes in liver attenuation were noted in those who responded (≥20% decrease in MaF) to diet modification and exercise than in those who did not. In conclusion, potential living liver donors with HS show significant intrasegmental and intersegmental variability in hepatic fat reduction on CT before and after diet modification and exercise.

Clinical Outcome of Residual Liver Volume and Hepatic Steatosis After Right-Lobe Living-Donor Hepatectomy

Background

We examine how residual liver volume (RLV) and hepatic steatosis (HS) of living liver donors affect the regeneration process and clinical outcomes.

Material/Methods

We longitudinally studied 58 donors who underwent right-lobe hepatectomy during the period February 2014 to February 2015 at a single medical institution. The patients were classified based on RLV (30–35%, 35–40%, 40–50%) subgroups and HS (<10%, 10–30%, 30–50%) subgroups. Clinical parameters such as clinical outcome, liver volumetric recovery (LVR,%) rate and remnant left-liver (RLL,%) growth rate were collected for analysis.

Results

The clinical features of postoperative peak total bilirubin (p=.024) were significant in the 3 RLV subgroups. Body mass index (p=.017), preoperative alanine transaminase (p<.001), and pleural effusion (p=.038) were significant in the 3 HS subgroups. The LVR rate and RLL growth rate equations showed significant variation in regeneration among the 3 RLV subgroups. The LVR rate and RLL growth rate equations did not show significant variation in regeneration among the 3 HS subgroups.

Conclusions

Hyperbilirubinemia was a risk factor in the small-RLV group, and a large amount of pleural effusion was a risk factor in the steatosis 30–50% group. Hepatic steatosis subgroups did not show significantly different degrees of regeneration. The safety of living donors was a major concern while we compiled the extended living-donor criteria presented in this paper.

Outcome of Living-Donor Liver Transplantation Using Grafts from Donors Treated for Fatty Liver

Background

The aim of this study was to determine the efficacy of treating donors’ fatty liver (FL) and to assess early graft function in recipients who received treated FL grafts in living-donor liver transplantation (LDLT).

Material/Methods

Data were collected for adult-to-adult LDLTs. Donors diagnosed with FL (FL group) received diet–exercise and pharmacological treatment. The perioperative findings and early transplanted graft function were compared with those of donors without FL (non-FL group) during the same period.

Results

Of 30 donors, 8 were determined to have FL. The median duration of treatment for FL was 58 days. The liver-to-spleen attenuation ratios on CT scan in the FL group were significantly improved after treatment: 0.95 (0.62–1.06) to 1.2 (1.12–1.46) (P=0.003). Liver biopsy prior to donor surgery showed ≤10% fatty infiltration. Postoperative laboratory findings of the donors in the FL group were comparable to those in the non-FL group: maximum alanine transaminase (189.6±94.7 IU/L vs. 196.8±57.4) and maximum total bilirubin (2.2±1.1 mg/dL vs. 1.7±0.5 mg/dL). No major complications were observed after donor hepatectomy in either group. There were no significant differences between the 2 groups in early graft function, as evaluated by laboratory data, ascites volume, and bile production 2 weeks postoperatively. Graft and patient survival were 100% in both groups at 3 months.

Conclusions

Preoperative intentional treatment for FL was effective. Early graft function and donor postoperative course were comparable in the 2 groups. These results suggest that well-treated steatotic grafts can be used without jeopardizing donor safety.

Comparison of CT methods for determining graft steatosis in living donor liver transplantation

PURPOSE

To evaluate and compare the diagnostic performance of non-enhanced computed tomography (NECT) and contrast-enhanced CT (CECT) attenuation indices in the assessment of hepatic steatosis by using biopsy as the reference standard.

MATERIALS AND METHODS

This retrospective study was approved by our Institutional Review Board. 55 Potential donors who underwent both NECT and triphasic CECT and core liver biopsy, were included the study. Average attenuation measurements that were obtained from multiple regions in liver, spleen, and psoas muscle on both unenhanced and CECT were used for analysis. Hepatic attenuation measurements were analyzed with and without normalization with the spleen and psoas muscle. Linear regression and receiver operating characteristic (ROC) curve analysis were used to evaluate the statistical association between CT indices and steatosis at histology.

RESULTS

Linear regression analysis confirmed the strongest correlation between steatosis and normalized measurements of hepatic attenuation with splenic attenuations on hepatic venous phase of CECT scan (R 0.821; R² 0.674 and R 0.816; R² 0.665, respectively). The use of ROC curve analysis also demonstrated that normalized measurements of hepatic attenuation with splenic attenuations on hepatic venous phase of CECT showed high diagnostic performance regarding the qualitative distinction of steatosis (AUC values greater than 0.9).

CONCLUSION

Attenuation measurements of liver normalized with spleen on hepatic venous phase may be useful in evaluating steatosis in donor candidates with moderate to severe steatosis who are unacceptable for liver donation. In this manner unnecessary liver biopsy may be avoided in those donor candidates.

In vivo percutaneous reflectance spectroscopy of fatty liver development in rats suggests that the elevation of the scattering power is an early indicator of hepatic steatosis

This study assessed whether there was a scattering spectral marker quantifiable by reflectance measurements that could indicate early development of hepatic steatosis in rats for potential applications to pre-procurement organ evaluation. Sixteen rats were fed a methionine-choline-deficient (MCD) diet and eight rats were fed a normal diet. Direct assessment of the liver parenchyma of rats in vivo was performed by percutaneous reflectance spectroscopy using a single fiber probe at the beginning of diet-intake and arbitrary post-diet-intake times up to 11 weeks to render longitudinal comparison. Histological sampling of the liver over the duration of diet administration was performed on two MCD-diet treated rats and one control rat euthanized after reflectance spectroscopy measurement. The images of hematoxylin/eosin-stained liver specimens were analyzed morphometrically to evaluate the lipid size changes associated with the level of steatosis. The MCD-diet-treated group ([Formula: see text]) had mild steatosis in seven rats, moderate in three rats, severe in six rats, and no other significant pathology. No control rats ([Formula: see text]) developed hepatic steatosis. Among the parameters retrieved from per-SfS, only the scattering power (can be either positive or negative) appeared to be statistically different between MCD-treated and control livers. The scattering power for the 16 MCD-diet-treated livers at the time of euthanasia and presenting various levels of steatosis was [Formula: see text], in comparison to [Formula: see text] of the eight control livers [Formula: see text]. When evaluated at days 12 and 13 combined, the scattering power of the 16 MCD-diet-treated livers was [Formula: see text], in comparison to [Formula: see text] of the eight control livers ([Formula: see text]). All of four MCD-treated livers harvested at days 12 and 13 presented mild steatosis with sub-micron size lipid droplets, even though none of the MCD-treated livers were sonographically remarkable for fatty changes. The elevation of the scattering power may be a valuable marker indicating early hepatic steatosis before the steatosis is sonographically detectable.

Predictive Factors of Liver Dysfunction After Right Hemihepatectomy for Adult Living Donor Liver Transplantation

BACKGROUND

Living liver donors represent a special group of patients. They are healthy individuals who are exposed to a major surgery, in which the dominant liver proportion is extracted as a graft. Of all potential donor-related morbidities, posthepatectomy liver dysfunction (PHLD) is the most significant as it may be directly related to donor mortality. We aimed to review our data of adult living donor liver transplantation (LDLT) utilizing the right hemiliver grafts to determine the incidence and potential predictors for the development of PHLD, defined according to the International Study Group of Liver Surgery.

METHODS

We reviewed the data of all adult living donors who underwent right hemihepatectomy during the period between May 2004 and 2016.

RESULTS

During the study period, 434 cases underwent right hemihepatectomy for adult LDLT. We divided our cases into 2 groups according to the occurrence of PHLD. A significant lower residual liver volume and percentage were noted in PHLD group. Longer intensive care unit stay and hospital stay, and more postoperative morbidities, were observed in PHLD group. PHLD occurred in 50 cases (11.5%), and most of them were grade A (47 cases [10.8%]). Two cases (0.5%) had grade B requiring diuretic therapy, and 1 case (0.2%) had grade C requiring ultrasound guided tube drainage and surgical exploration finally.

CONCLUSIONS

We should not underestimate the risks of liver donation surgery, especially when utilizing the right hemiliver graft. Donor safety should be ensured by accurate preoperative volumetric assessment of the remnant liver and remnant liver volume limitations must be strictly followed.

Can negligible hepatic steatosis determined by magnetic resonance imaging-proton density fat fraction obviate the need for liver biopsy in potential liver donors?

The purpose of this study is to determine whether magnetic resonance (MR)-proton density fat fraction (PDFF) estimate of negligible hepatic fat percentage (<5%) can exclude significant hepatic steatosis (≥10%) in living liver donor candidates obviating the need for liver biopsy and to perform intraindividual comparisons between MR-PDFF techniques for hepatic steatosis quantification. In an ethics-approved retrospective study, 144 liver donor candidates with magnetic resonance spectroscopy (MRS) and 6-echo Dixon magnetic resonance imaging (MRI) between 2013 and 2015 were included. A subset of 32 candidates underwent liver biopsy. Hepatic fat percentage was determined using MR-PDFF and histopathology-determined fat fraction as the reference standard. A receiver operating characteristic analysis with positive predictive value, negative predictive value (NPV), sensitivity, and specificity was performed to discriminate between clinically significant steatosis (≥10%) or not (<10%) at MRS-PDFF and MRI-PDFF thresholds of 5% and 10%. Pearson correlation and Bland-Altman analyses between MRS-PDFF and MRI-PDFF were performed for intraindividual comparison of hepatic steatosis estimation. There was significant association between MRS-PDFF and MRI-PDFF with HP-FP. High NPV of 95% (95% confidence interval [CI], 78%-99%) and 100% (95% CI, 76%-100%) as well as an area under the curve of 0.90 (95% CI, 0.79-1.0) and 0.93 (95% CI, 0.84-1.0) were obtained with a cutoff threshold of 5% MRI-PDFF and MRS-PDFF, respectively, to exclude clinically significant steatosis (≥10%). Intraindividual comparison between MRS-PDFF and MRI-PDFF showed a Pearson correlation coefficient of 0.83. Bland-Altman analysis showed a mean difference of 1% with 95% limits of agreement between -1% and 3%. MR-PDFF estimate of negligible hepatic fat percentage (<5%) has sufficient NPV for excluding clinically significant hepatic steatosis (≥10%) in living liver donor candidates obviating the need for liver biopsy. It may be sufficient to acquire only the multiecho Dixon MRI-PDFF for hepatic steatosis estimation. Liver Transplantation 24 470-477 2018 AASLD.

Accuracy of MR Imaging and MR Spectroscopy for Detection and Quantification of Hepatic Steatosis in Living Liver Donors: A Meta-Analysis

Purpose To determine the accuracy of magnetic resonance (MR) imaging for detection and quantification of hepatic steatosis (HS) in living liver donor candidates. Materials and Methods A systematic search of the literature was performed to find studies on the diagnostic and quantitative accuracy of MR imaging for assessment of HS in liver donors. The Quality Assessment of Diagnostic Accuracy Studies 2 tool was used, and patient selection, index text, reference standard, and study flow and timing were assessed to evaluate the quality of each included study. Pooled sensitivity, specificity, positive and negative likelihood ratios, hierarchical summary receiver operating characteristic (ROC) curves, and the area under the curve were estimated by using hierarchical summary ROC and bivariate random-effects models. Results Eight studies involving 934 subjects were eligible for the meta-analysis. For detection of HS with MR imaging and/or MR spectroscopy in living liver donors, the pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio, respectively, were 0.89 (95% confidence interval [CI]: 0.75, 0.95), 0.84 (95% CI: 0.76, 0.89), 5.53 (95% CI: 3.71, 8.25), and 0.14 (95% CI: 0.06, 0.31). The area under the curve was 0.92 (95% CI: 0.89, 0.94). For detection of substantial HS (>10% to >30% HS at liver pathologic examination, as defined in each study), these corresponding diagnostic estimates were 0.91 (95% CI: 0.82, 0.95), 0.89 (95% CI: 0.84, 0.93), 8.30 (95% CI: 5.47, 12.59), 0.10 (95% CI: 0.05, 0.21), and 0.96 (95% CI: 0.93, 0.97), respectively. Moderate heterogeneity was detected. No publication bias was detected (P = .12). Conclusion MR imaging and MR spectroscopy show high sensitivity and specificity for detection of HS, especially when HS is substantial, and may be useful for noninvasive evaluation of HS in living liver donors. ^© RSNA, 2016 Online supplemental material is available for this article.

Ischemia–reperfusion injury in patients with fatty liver and the clinical impact of steatotic liver on hepatic surgery

Hepatic steatosis is one of the most common hepatic disorders in developed countries. The epidemic of obesity in developed countries has increased with its attendant complications, including metabolic syndrome and non-alcoholic fatty liver disease. Steatotic livers are particularly vulnerable to ischemia/reperfusion injury, resulting in an increased risk of postoperative morbidity and mortality after liver surgery, including liver transplantation. There is growing understanding of the molecular and cellular mechanisms and therapeutic approaches for treating ischemia/reperfusion injury in patients with steatotic livers. This review discusses the mechanisms underlying the susceptibility of steatotic livers to ischemia/reperfusion injuries, such as mitochondrial dysfunction and signal transduction alterations, and summarizes the clinical impact of steatotic livers in the setting of hepatic resection and liver transplantation. This review also describes potential therapeutic approaches, such as ischemic and pharmacological preconditioning, to prevent ischemia/reperfusion injury in patients with steatotic livers. Other approaches, including machine perfusion, are also under clinical investigation; however, many pharmacological approaches developed through basic research are not yet suitable for clinical application.

Risk of venous congestion in live donors of extended right liver graft

AIM: To investigate middle hepatic vein (MHV) management in adult living donor liver transplantation and safer remnant volumes (RV).

METHODS: There were 59 grafts with and 12 grafts without MHV (including 4 with MHV-5/8 reconstructions). All donors underwent our five-step protocol evaluation containing a preoperative protocol liver biopsy Congestive vs non-congestive RV, remnant-volume-body-weight ratios (RVBWR) and postoperative outcomes were evaluated in 71 right graft living donors. Dominant vs non-dominant MHV anatomy in total liver volume (d-MHV/TLV vs nd-MHV/TLV) was constellated with large/small congestion volumes (CV-index). Small for size (SFS) and non-SFS remnant considerations were based on standard cut-off- RVBWR and RV/TLV. Non-congestive RVBWR was based on non-congestive RV.

RESULTS: MHV and non-MHV remnants showed no significant differences in RV, RV/TLV, RVBWR, total bilirubin, or INR. SFS-remnants with RV/TLV < 30% and non-SFS-remnants with RV/TLV ≥ 30% showed no significant differences either. RV and RVBWR for non-MHV (n = 59) and MHV-containing (n = 12) remnants were 550 ± 95 mL and 0.79 ± 0.1 mL vs 568 ± 97 mL and 0.79 ± 0.13, respectively (P = 0.423 and P = 0.919. Mean left RV/TLV was 35.8% ± 3.9%. Non-MHV (n = 59) and MHV-containing (n = 12) remnants (34.1% ± 3% vs 36% ± 4% respectively, P = 0.148. Eight SFS-remnants with RVBWR < 0.65 had a significantly smaller RV/TLV than 63 non-SFS-remnants with RVBWR ≥ 0.65 [SFS: RV/TLV 32.4% (range: 28%-35.7%) vs non-SFS: RV/TLV 36.2% (range: 26.1%-45.5%), P < 0.009. Six SFS-remnants with RV/TLV < 30% had significantly smaller RVBWR than 65 non-SFS-remnants with RV/TLV ≥ 30% (0.65 (range: 0.6-0.7) vs 0.8 (range: 0.6-1.27), P < 0.01. Two (2.8%) donors developed reversible liver failure. RVBWR and RV/TLV were concordant in 25%-33% of SFS and in 92%-94% of non-SFS remnants. MHV management options including complete MHV vs MHV-4A selective retention were necessary in n = 12 vs n = 2 remnants based on particularly risky congestive and non-congestive volume constellations.

CONCLUSION: MHV procurement should consider individual remnant congestive- and non-congestive volume components and anatomy characteristics, RVBWR-RV/TLV constellation enables the identification of marginally small remnants.

Liver failure after hepatocellular carcinoma surgery

PURPOSE

The aim of this study was to construct a prediction model for posthepatectomy liver failure (PHLF), as defined by the International Study Group of Liver Surgery, and evaluate its accuracy in hepatocellular carcinoma (HCC) patients with cirrhosis or chronic hepatitis.

METHODS

A total of 277 consecutive hepatectomies for HCC between 2005 and 2013 were analyzed retrospectively. Multivariate logistic regression analysis was used to develop a predictive model for PHLF. The sensitivity, specificity, and area under the receiver operating characteristic (AUROC) curve were evaluated. The Hosmer-Lemeshow goodness-of-fit test was used to assess the model calibration. The constructed model was internally validated by k-fold cross-validation (k=5).

RESULTS

PHLF developed in 12.6% of hepatectomies. Multivariate analysis identified the following variables as predictors of PHLF: elevated preoperative serum bilirubin level, elevated preoperative international normalized ratio, and intraoperative packed red blood cell transfusion. The predictive model allowed discrimination between patients who developed PHLF and those who did not, with a sensitivity of 82.9%, specificity of 72.3%, and AUROC curve of 0.81 (95% CI, 0.74 to 0.89). The Hosmer-Lemeshow test indicated a good fit (P=0.545). The AUROC curve of the developed model was significantly greater than that of the model for end-stage liver disease (MELD) score (P=0.014), suggesting that the former model is better at predicting the PHLF than the latter one.

CONCLUSIONS

The developed model could be useful for predicting the occurrence of PHLF in HCC patients with underlying liver disease.

Hepatic steatosis in living liver donor candidates: preoperative assessment by using breath-hold triple-echo MR imaging and 1H MR spectroscopy

PURPOSE

To evaluate the diagnostic performance of both breath-hold T2*-corrected triple-echo spoiled gradient-echo water-fat separation magnetic resonance (MR) imaging (triple-echo imaging) and high-speed T2-corrected multiecho hydrogen 1 ((1)H) MR spectroscopy in the assessment of macrovesicular hepatic steatosis in living liver donor candidates by using histologic assessment as a reference standard.

MATERIALS AND METHODS

The institutional review board approved this retrospective study with waiver of the need to obtain informed consent. One hundred eighty-two liver donor candidates who had undergone preoperative triple-echo imaging and single-voxel (3 × 3 × 3 cm) MR spectroscopy performed with a 3.0-T imaging unit and who had also undergone histologic evaluation of macrovesicular steatosis were included in this study. In part 1 of the study (n = 84), the Pearson correlation coefficient was calculated. Receiver operating characteristic (ROC) curve analysis was performed to detect substantial (≥10%) macrovesicular steatosis. In part 2 of the study, with a different patient group (n = 98), diagnostic performance was evaluated by using the diagnostic cutoff values determined in part 1 of the study.

RESULTS

The correlation coefficients of triple-echo MR imaging and MR spectroscopy with macrovesicular steatosis were 0.886 and 0.887, respectively. The areas under the ROC curve for detection of substantial macrovesicular steatosis were 0.959 and 0.988, with cutoff values of 4.93% and 5.79%, respectively, and without a significant difference (P = .328). In the part 2 study group, sensitivity and specificity were 90.9% (10 of 11) and 86.2% (75 of 87) for triple-echo MR imaging and 90.9% (10 of 11) and 86.2% (75 of 87) for MR spectroscopy, respectively.

CONCLUSION

Either breath-hold triple-echo MR imaging or MR spectroscopy can be used to detect substantial macrovesicular steatosis in living liver donor candidates. In the future, this may allow selective biopsy in candidates who are expected to have substantial macrovesicular steatosis on the basis of MR-based hepatic fat fraction.

Utility of controlled attenuation parameter measurement for assessing liver steatosis in Japanese patients with chronic liver diseases

AIM

Steatosis is a common histological feature of chronic liver disease, especially alcoholic and non-alcoholic fatty liver disease, as well as chronic hepatitis C. A recent study showed that evaluating the controlled attenuation parameter (CAP) with transient elastography was an efficient way of non-invasively determining the severity of hepatic steatosis. The objective of this study was to prospectively evaluate the utility of CAP for diagnosing steatosis in patients with chronic liver disease.

METHODS

One hundred and fifty-five consecutive patients with suspected chronic liver disease underwent steatosis diagnosis using CAP, blood sample analyses, computed tomography for assessing the liver/spleen ratio and liver biopsy. Steatosis was graded according to the percentage of fat-containing hepatocytes: S0, less than 5%; S1, 5-33%; S2, 34-66%; and S3: more than 66%.

RESULTS

The CAP was significantly correlated with steatosis grade, and there were significant differences between the CAP value of the S0 patients and those of the patients with other grades of steatosis. S0 and S1-3 hepatic steatosis were considered to represent mild and significant steatosis, respectively. The CAP values of the patients with mild and significant steatosis were significantly different (P < 0.0001). The area under the receiver-operator curve (AUROC) value of the CAP for diagnosing significant steatosis was 0.878 (95% confidence interval, 0.818-0.939), and the optimal CAP cut-off value for detecting significant steatosis was 232.5 db/m. In multivariate analysis, the CAP (P = 0.0002) and the liver to spleen ratio (P = 0.004) were found to be significantly associated with significant steatosis.

CONCLUSION

The CAP is a promising tool for rapidly and non-invasively diagnosing steatosis.

[Alcoholic and non-alcoholic steatohepatitis: who is affected and what can we do for them?]

The most common causes of steatohepatitis are alcohol intake and metabolic disorders. Several methods based on biochemical determinations (carbohydrate deficient transferrin) and questionnaires (AUDIT, CAGE, MALE) are useful for detecting surreptitious alcohol intake. Although new non-invasive methods are under development, based both on lipidomics (Owl-Liver(®)) and on biochemical determinations and anthropometric parameters (NAFLD Fibrosis score) or imaging methods (DeMILI NASH-MRi(®)), none has been proposed as definitive and the gold standard continues to be liver biopsy. The pathogenesis of alcoholic and non-alcoholic steatohepatitis shares some elements such as insulin resistance, cytochrome CYP2E1-mediated oxidative stress, adiponutrin and its PNPLA3 gene, and the microbiota. The first-line treatment consists of lifestyle changes, including giving up alcohol, diet and exercise.

The impact of hepatic steatosis on liver regeneration after partial hepatectomy

BACKGROUND & AIM

Experimental studies in animals have suggested that liver regeneration is impaired in steatotic livers. However, few studies have focused on the impact of steatosis in patients undergoing partial hepatectomy (PH). This study aims to determine the role of steatosis on liver regeneration in humans following PH.

METHODS

Eighty-eight patients undergoing PH were included in this study. All patients underwent CT-scanning of the liver preoperatively and 7 days after surgery. Additional CT-scans were performed 6 months post-operatively. Preoperative and post-operative volumes of the total liver (TLV), future liver remnant (FLR) and liver remnant (LR) were measured on CT-scans. Regeneration indices (RI) were calculated at 7 days and 6 months using the formula: (Volume LR-Volume FLR)/Volume FLR × 100%. Based on histological examination of the resected part of the liver, patients were classified into three groups: (1) no steatosis, (2) mild steatosis (1-29%) and (3) moderate-to-severe steatosis (≥30%).

RESULTS

The early RI (at day 7) was 40%, 24% and 20% for patients in group 1, 2 and 3 respectively. Late RI (at 6 months) was 81% for group 1, 44% for group 2 and 22% for group 3 (P = 0.019). At 7 days, the LR represented 79%, 80% and 79% of the TLV for groups 1-3. At 6 months, this was 93%, 92% and 79% respectively.

CONCLUSION

Although early RI after PH did not differ in patients with or without steatosis, the late RI in patients with moderate-to-severe steatosis was lower, suggesting that late liver regeneration is impaired in these patients.

Underlying steatohepatitis, but not simple hepatic steatosis, increases morbidity after liver resection: a case-control study

Despite the high prevalence of fatty liver disease, the safety of liver resection in settings of steatohepatitis (SH) or hepatic steatosis is poorly understood. The aim of this study was to determine whether underlying SH or simple hepatic steatosis increases morbidity after liver resection. We compared patients undergoing liver resection with underlying SH or greater than 33% simple hepatic steatosis to controls selected for similar demographics, diagnoses, comorbidities, preoperative chemotherapy treatments, and extent of partial hepatectomy. Primary endpoints included postoperative overall and hepatic-related morbidity. One hundred and two patients with SH and 72 with greater than 33% simple hepatic steatosis who underwent liver resection from 2000 to 2011 were compared to corresponding controls. There were no differences in extent or approach of liver resection, malignant indications, preoperative chemotherapy treatment, elements of metabolic syndrome, alcohol use history, American Society of Anesthesiologists score, age, or gender between patients with SH or simple steatosis and corresponding controls. Ninety-day postoperative overall morbidity (56.9% versus 37.3%; P = 0.008), any hepatic-related morbidity (28.4% versus 15.7%; P = 0.043), surgical hepatic complications (19.6% versus 8.8%; P = 0.046), and hepatic decompensation (16.7% versus 6.9%; P = 0.049) were greater among SH patients, compared to corresponding controls. In contrast, there were no differences in postoperative overall morbidity (34.7% versus 44.4%; P = 0.310), any hepatic-related morbidity (19.4% versus 19.4%; P = 1.000), surgical hepatic complications (13.9% versus 9.7%; P = 0.606), or hepatic decompensation (8.3% versus 9.7%; P = 0.778) between simple hepatic steatosis patients and corresponding controls. Using multivariable logistic regression, SH was independently associated with postoperative overall (odds ratio [OR], 2.316; 95% confidence interval [95% CI]: 1.267-4.241; P = 0.007) and any hepatic-related (OR, 2.722; 95% CI: 1.201-6.168; P = 0.016) morbidity.

CONCLUSION

Underlying SH, but not simple hepatic steatosis, increases overall and hepatic-related morbidity after liver resection.

Decreased Mrp2 transport in severe macrovesicular fatty liver grafts

BACKGROUND

Severe macrosteatotic liver has been regarded as a donor contraindication for liver transplantation. However, it has not yet been determined whether hepatocytes lose function before cold ischemia. This study was designed to elucidate certain pathophysiological alterations and how to ameliorate such hepatic dysfunctions.

MATERIALS AND METHODS

Wistar rats were fed with a choline-deficient diet (CD) for up to 6 wk, and their livers were then perfused with Krebs-Henseleit buffer to examine bile output and biliary constituents. Organic anion transport from hepatocellular canalicular membranes through Mrp2 was examined by kinetic analyses for biliary exclusion of 5-carboxyfluorescein (CF), a fluoroprobe excreted through Mrp2.

RESULTS

Macrovesicular fatty deposits exceeded 60% and serum aspartate aminotransferase (AST) increased on 6-wk CD (CD6w), but not 3-wk CD (CD3w). Mrp2-deficient rat livers (Eisai hyperbilirubinemia) with 3-wk CD were more vulnerable than CD3w livers. In CD6w rats, bile flow rate and biliary glutathione significantly decreased. These declines coincided with the intracellular localization of Mrp2. Moreover, kinetic analyses for biliary CF revealed significant delay in 6-wk CD-fed rat livers. Pioglitazone, a ligand of PPARγ activating protein kinase A (PKA), significantly attenuated this delay by sorting Mrp2 into bile canalicular membranes. However, a PKA inhibitor blunted the increase in CF exclusion, re-localizing Mrp2 into the hepatocellular cytoplasm. A thromboxane A2 synthase inhibitor also ameliorated the CF exclusion delay.

CONCLUSION

Pioglitazone activated PKA, increasing Mrp2 transports to detoxify xenobiotics. Pioglitazone may allow the donor indications for liver transplantation to be expanded to include severe macrovesicular fatty livers.

Mini-incision right hepatic lobectomy with or without laparoscopic assistance for living donor hepatectomy

Minimally invasive procedures are considered to be safe and effective approaches to the management of surgical liver disease. However, this indication remains controversial for living donor hepatectomy. Between 2000 and 2011, living donor right hepatectomy (LDRH) was performed 58 times. Standard right hepatectomy was performed in 30 patients via a subcostal incision with a midline extension. Minimally invasive procedures began to be used for LDRH in 2008. A hybrid technique (hand-assisted laparoscopic liver mobilization and minilaparotomy for parenchymal dissection) was developed and used in 19 patients. In 2010, an upper midline incision (10 cm) without laparoscopic assistance for LDRH was innovated, and this technique was used in 9 patients. The perioperative factors were compared, and the indications for minimally invasive LDRH were investigated. The operative blood loss was significantly less for the patients undergoing a minimally invasive procedure versus the patients undergoing the standard procedure (212 versus 316 mL, P = 0.001), and the operative times were comparable. The length of the hospital stay was significantly shorter for the minimally invasive technique group (5.9 versus 7.8 days, P < 0.001). The complication rates were 23% and 25% for the standard technique and minimally invasive technique groups, respectively (P = 0.88). Patients undergoing minilaparotomy LDRH had a body mass index (24.0 kg/m(2)) similar to that of the hybrid technique patients (25.8 kg/m(2), P = 0.36), but the graft size was smaller (780 versus 948 mL, P = 0.22). In conclusion, minimally invasive LDRH can be performed without safety being impaired. LDRH with a 10-cm upper midline incision and without laparoscopic assistance may be appropriate for donors with a smaller body mass. Laparoscopic assistance can be added as needed for larger donors. This type of LDRH with a 10-cm incision is innovative and is recommended for experienced centers.

Effects of donor steatosis on liver biochemistry and significance of body mass index in predicting steatosis

BACKGROUND

Hepatic steatosis is a major concern in living donor liver transplantation. Factors affecting hepatic functional status after a donor right hepatectomy (with the middle hepatic vein included in the graft) with a focus on changes owing to steatosis were retrospectively studied.

METHODS

Donors (n = 325) were categorized into three groups: G0 (no steatosis, n = 178), G1 (< = 10% steatosis, n = 128) and G2 (>10% steatosis, n = 19). Donors with >20% steatosis were excluded. Changes in aspartate aminotransferase (AST), alanine aminotransferase (ALT), bilirubin levels and prothrombin time (PT) were assessed. Factors predicting steatosis were also assessed. A liver biopsy was performed on selected donors.

RESULTS

The ALT level rose until day 3 in G1 and day 6 in G2 (P < 0.05). The AST level rose until day 7 in G2 (P < 0.05) but stayed unchanged in G1. The bilirubin level was higher only on day 1 in G2 (P < 0.05). By day 30, no significant difference between any groups was noted. Receiver-operating characteristic (ROC) area under the curve for body mass index (BMI) on predicting steatosis was 0.75 [confidence interval (CI) = 69-80]. Among donors with a BMI > 23.5 kg/m(2), 75% had steatosis. Five donors had >20% steatosis and were not assessed.

CONCLUSION

Using a liver with up to 20% steatosis in right liver donation, even if the middle hepatic vein is included in the graft, is safe. For Asian donors, a BMI > 23.5 kg/m(2) is a guide in deciding whether to perform a liver biopsy for steatosis.

Safety and feasibility of diet-treated donors with steatotic livers at the initial consultation for living-donor liver transplantation

BACKGROUND

The purpose of this study was to evaluate both safety of diet-treated donors and the feasibility of their use for living-donor liver transplantation (LDLT).

METHODS

A total of 128 living donors were enrolled in this study between April 2003 and March 2010. Of them, 41 were diagnosed with hepatic steatosis at the initial consultation. Donor selection was based on the findings of liver biopsy accompanied with normalization of liver function tests after diet treatment consisting of an 800 to 1400 kcal/day diet and a 100 to 400 kcal/day exercise without drug treatment, targeting body mass index of 22 kg/m².

RESULTS

Body mass index of diet-treated donors was significantly reduced with diet from 23.3 ± 0.6 to 21.9 ± 0.4 kg/m² (P<0.0001). Liver function tests associated with fatty liver, including alanine aminotransferase, gamma-glutamyl transpeptidase, and total cholesterol levels, also improved with diet (P=0.0128, 0.0016, and 0.0004, respectively). The liver biopsy results of most of these donors showed stage 0/1 fibrosis and minimal/mild steatosis after the diet therapy. Surgical outcomes, including postoperative liver function tests, perioperative complications, and liver regeneration rates, did not significantly differ between nondiet-treated and diet-treated donors. Surgical outcomes and the overall survival did not significantly differ between recipients of grafts from nondiet-treated and diet-treated donors.

CONCLUSION

The use of diet-treated donors for living-donor liver transplantation is feasible with respect to donor safety and the outcome of the recipient when strict selection criteria are used.

Surgical outcome of right liver donors in living donor liver transplantation: single-center experience with 500 cases

BACKGROUND

With the increasing number of living donor liver transplantation (LDLT), concerns regarding morbidity and mortality of donors have become inevitable. Thus, the aim of the present study was to find ways to reduce the rate of morbidity and mortality of donors by analyzing our experience.

METHODS

A retrospective clinicopathologic analysis was performed for 500 consecutive living donors who underwent donor right hepatectomy between May 1999 and February 2011. We chronologically divided those procedures into three periods: period A (n = 100), period B (n = 200), and period C (n = 200). Surgical outcomes according to each period were then compared.

RESULTS

Over time, the following factors have decreased: the operative time, the amount of transfusions during surgery, hospital stay, and the incidence of biliary complications. No mortality developed. Even though the total complication rate was high (21.6 %, n = 108) including 10.6 % (n = 53) of biliary complications, the grade 3 complication rate was only 9.4 % (n = 47). In most patients with grade 3 complication, interventional therapies via radiologic or endoscopic approaches corrected these complications, and reoperation was required for ten patients (2 %). Whereas biliary complications were related with operation period (period B or C compared to period A; relative risk [RR] 2.10, P = 0.049, 95 % CI 1.01-4.39) and operative time (RR 1.01, P = 0.027, 95 % CI 1.00-1.02), postoperative hyperbilirubinemia (serum total bilirubin ≥ 5 mg/dL) was related with male gender (RR 2.68, P = 0.039, 95 % CI 1.05-6.85) and ≥ 25 % liver steatosis (RR 3.35, P = 0.053, 95 % CI 0.99-11.38).

CONCLUSIONS

Optimization of donor selection as well as institutional experience is imperative to improve the surgical outcome. Even though donor hepatectomy was associated with relatively higher complication rate, most complications showed low-grade severity which could be corrected by interventional therapies.

Effects of the liver volume and donor steatosis on errors in the estimated standard liver volume

An accurate assessment of donor and recipient liver volumes is essential in living donor liver transplantation. Many liver donors are affected by mild to moderate steatosis, and steatotic livers are known to have larger volumes. This study analyzes errors in liver volume estimation by commonly used formulas and the effects of donor steatosis on these errors. Three hundred twenty-five Asian donors who underwent right lobe donor hepatectomy were the subjects of this study. The percentage differences between the liver volumes from computed tomography (CT) and the liver volumes estimated with each formula (ie, the error percentages) were calculated. Five popular formulas were tested. The degrees of steatosis were categorized as follows: no steatosis [n = 178 (54.8%)], ≤ 10% steatosis [n = 128 (39.4%)], and >10% to 20% steatosis [n = 19 (5.8%)]. The median errors ranged from 0.6% (7 mL) to 24.6% (360 mL). The lowest was seen with the locally derived formula. All the formulas showed a significant association between the error percentage and the CT liver volume (P < 0.001). Overestimation was seen with smaller liver volumes, whereas underestimation was seen with larger volumes. The locally derived formula was most accurate when the liver volume was 1001 to 1250 mL. A multivariate analysis showed that the estimation error was dependent on the liver volume (P = 0.001) and the anthropometric measurement that was used in the calculation (P < 0.001) rather than steatosis (P ≥ 0.07). In conclusion, all the formulas have a similar pattern of error that is possibly related to the anthropometric measurement. Clinicians should be aware of this pattern of error and the liver volume with which their formula is most accurate.

Metabolic syndrome and hepatic resection: improving outcome

OBJECTIVE

A review of the peri-operative risk associated with hepatic resection in patients with metabolic syndrome (MetS) and identification of measures for the improvement of cardiometabolic disturbances and liver-related mortality.

BACKGROUND

MetS and its hepatic manifestation non-alcoholic fatty liver disease (NAFLD) are associated with an increased operative mortality in spite of a significant improvement in peri-operative outcome after hepatic resection.

METHODS

A review of the English literature on MetS, liver resection and steatosis was performed from 1980 to 2011 using the MEDLINE and PubMed databases.

RESULTS

MetS is a predictor of NAFLD and patients with multiple metabolic risk factors may harbour non-alcoholic steatohepatitis (NASH) predictive of operative and cardiovascular mortality. Pre-operative diagnosis of unsuspected NASH with the selective use of a liver biopsy can modify the operative strategy by limiting the extent of hepatic resection, avoiding or altering the pre-operative chemotherapy regimen and the utilization of portal vein embolization. Thiazolidinediones are therapeutic for MetS and NASH and Vitamin E for active NASH; however, their utility in improving the peri-operative outcome after hepatic resection is unknown. A short-term regimen for weight loss improves post-operative patient and liver-related outcomes in patients with >30% steatosis. Cardiovascular disease associated with MetS or NAFLD should be managed aggressively. Peri-operative measures to minimize thrombotic events and acute renal injury secondary to the pro-inflammatory, prothrombotic state of MetS may further improve the outcome.

CONCLUSION

Potential candidates for hepatic resection should be screened for MetS as the pre-operative identification of NASH, short-term treatment of significant steatosis, cardiovascular risk assessment and optimization of each component of MetS may improve the peri-operative outcome in this high-risk subset of patients.

Systematic review and meta-analysis of steatosis as a risk factor in major hepatic resection

Background

The risk of major hepatic resection in patients with hepatic steatosis remains controversial. A meta-analysis was performed to establish the best estimate of the impact of steatosis on patient outcome following major hepatic surgery.

Methods

A systematic search was performed following Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. Risk ratios (RRs) for complication and mortality rates were calculated for patients with no, less than 30 per cent and at least 30 per cent steatosis, and a meta-analysis was carried out.

Results

Of six observational studies identified, four including a total of 1000 patients were subjected to meta-analysis; two others were tabulated separately. Compared with patients without steatosis, those with less than 30 per cent and at least 30 per cent steatosis had a significantly increased risk of postoperative complications, with a RR of 1·53 (95 per cent confidence interval (c.i.) 1·27 to 1·85) and 2·01 (1·66 to 2·44) respectively. Patients with at least 30 per cent steatosis had an increased risk of postoperative death (RR 2·79, 95 per cent c.i. 1·19 to 6·51).

Conclusion

Patients with steatosis had an up to twofold increased risk of postoperative complications, and those with excessive steatosis had an almost threefold increased risk of death.

Major adverse events, pretransplant assessment and outcome prediction

Liver cirrhosis and portal hypertension pose enormous loss of lives and resources throughout the world, especially in endemic areas of chronic viral hepatitis. Although the pathophysiology of cirrhosis is not completely understood, the accumulating evidence has paved the way for better control of the complications, including gastroesophageal variceal bleeding, hepatic encephalopathy, ascites, hepatorenal syndrome, hepatopulmonary syndrome and portopulmonary hypertension. Modern pharmacological and interventional therapies have been designed to treat these complications. However, liver transplantation (LT) is the only definite treatment for patients with preterminal end-stage liver disease. To pursue successful LT, the meticulous evaluation of potential recipients and donors is pivotal, especially for living donor transplantation. The critical shortage of cadaveric donor livers is another concern. In many Asian countries, cultural and religious concerns further limit the number of the donors, which lags far behind that of the recipients. The model for end-stage liver disease (MELD) scoring system has recently become the prevailing criterion for organ allocation. Initial results showed clear benefits of moving from the Child-Turcotte-Pugh-based system toward the MELD-based organ allocation system. In addition to the MELD, serum sodium is another important prognostic predictor in patients with advanced cirrhosis. The incorporation of serum sodium into the MELD could enhance the performance of the MELD and could become an indispensable strategy in refining the priority for LT. However, the feasibility of the MELD in combination with sodium in predicting the outcome for patients on transplant waiting list awaits actual outcome data before this becomes standard practice in the Asia-Pacific region.

Non-invasive assessment and quantification of liver steatosis by ultrasound, computed tomography and magnetic resonance

Hepatic steatosis is the most prevalent liver disorder in the developed world. It is closely associated with features of metabolic syndrome, especially insulin resistance and obesity. The two most common conditions associated with fatty liver are alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). Liver biopsy is considered the gold standard for the assessment of liver fat, but there is a need for less invasive diagnostic techniques. New imaging modalities are emerging, which could provide more detailed information about hepatic tissue or even replace biopsy. In the present review, available imaging modalities (ultrasound, computed tomography, magnetic resonance imaging and proton magnetic resonance spectroscopy) are presented which are employed to detect or even quantify the fat content of the liver. The advantages and disadvantages of the above-mentioned imaging modalities are discussed. Although none of these techniques is able to differentiate between microvesicular and macrovesicular steatosis and to reveal all features visible using histology, the proposed diagnostic modalities offer a wide range of additional information such as anatomical and morphological information non-invasively. In particular, magnetic resonance imaging and proton magnetic resonance spectroscopy are able to quantify the hepatic fat content hence avoiding exposure to radiation. Except for proton magnetic resonance spectroscopy, all modalities offer additional information about regional fat distribution within the liver. MR elastography, which can estimate the amount of fibrosis, also appears promising in the differentiation between simple steatosis and steatohepatitis.