Effect of macrovescicular steatosis and other donor and recipient characteristics on the outcome of liver transplantation

Liver transplantation using fatty livers: always feasible?

Steatotic liver grafts represent the most common type of "extended criteria" organs that have been introduced during the last two decades due to the disparity between liver transplant candidates and the number available organs. A precise definition and reliable and reproducible method for steatosis quantification is currently lacking and the potential influence of the chemical composition of hepatic lipids has not been addressed. In our view, these shortcomings appear to contribute significantly to the inconsistent results of studies reporting on graft steatosis and the outcome of liver transplantation. In this review, various definitions, prevalence and methods of quantification of liver steatosis will be covered. Ischemia/reperfusion injury of the steatotic liver and its consequences on post-transplant outcome will be discussed. Selection criteria for organ allocation and a number of emerging protective strategies are suggested.

Frozen-section diagnosis in donor livers: error rate estimation of steatosis degree

A high degree of macrovesicular steatosis is associated with a significant risk of graft dysfunction. Most centers, including ours, consider 60% the limit value for transplantability, while others have adopted 30% as a cutoff. Pretransplant frozen-section (PFS) evaluation is used for reliable quantification of steatosis. However, the accuracy of PFS analysis for the degree of steatosis has largely been debated due to its high grade of variability and subjectivity. The aim of our study was to evaluate the accuracy of PFS diagnosis compared with subsequent paraffin histology samples. We retrospectively analyzed PFS from 52 consecutive liver donors. All PFS were blindly reviewed by two pathologists. The results were graded according to two classifications: (A) lower or higher than 60% steatosis, or (B) mild (0%-30%), moderate (30%-60%), or severe (>60%) steatosis. The rate of error for A (two-grade classification score) was 1.9% with the erroneous discharge of a viable organ. The error rate for B (three-grade classification score) was 7.7% with four discrepancies. In three cases, the discrepancy was related to the mild to moderate cutoff value, leading to a clinical error rate of 5.8% (discharging organs with statosis >30%, when we used more strict criteria). Our study validated PFS analysis as a reliable technique when the maximum value for organ transplantation was 60% steatosis. There was a higher error rate when a cutoff value of 30% was used. This finding suggests the usefulness of another technique to support a more precise steatosis evaluation.

Noncirrhotic human nonalcoholic fatty liver disease induces portal hypertension in relation to the histological degree of steatosis

INTRODUCTION

We earlier showed in an animal model that steatosis, in the absence of fibrosis or inflammation, induces a significant rise in portal pressure. The relevance of these findings for human pathology is unknown till date.

AIMS

To study portal pressure in nonalcoholic fatty liver disease patients and to identify factors possibly related to steatosis-induced changes in liver haemodynamics.

MATERIALS AND METHODS

Patients presenting with a problem of overweight and with noninvasive signs of liver involvement were proposed for transjugular liver biopsy. The biopsy was scored according to the Nonalcoholic Steatohepatitis Clinical Research Network scoring system.

RESULTS

Fifty consecutive patients were studied. Mean age was 47.9 ± 13.6 years; 31 (62%) of them were female. Hepatic venous pressure gradient (HVPG) was normal in 27 patients (54%), borderline (5 mmHg) in nine (18%) and elevated in 14 patients (28%). For further analysis those with a HVPG of 5 mmHg were considered normal (group 1). HVPG was 8.8 ± 2.6 mmHg in those with an elevated HVPG (group 2) versus 3.4 ± 1.2 mmHg in group 1 (P < 0.0001). In both the groups, only one patient had cirrhosis; 26 of 36 (group 1) and nine of 14 patients (group 2) had fibrosis score 0. Fibrosis score was not significantly different (P = 0.530). Perisinusoidal fibrosis score was not significantly different (P = 0.186). Steatosis was the only histological feature that significantly differed between the groups (P = 0.016). The degree of steatosis (P = 0.010) was the only independent predictor of the presence of portal hypertension.

CONCLUSION

Human nonalcoholic fatty liver disease can, even in the absence of significant fibrosis, induce portal hypertension, correlated with the severity of the steatosis.

Assessment of hepatic steatosis in patients undergoing liver resection: comparison of US, CT, T1-weighted dual-echo MR imaging, and point-resolved 1H MR spectroscopy

PURPOSE

To compare the diagnostic performance of ultrasonography (US), computed tomography (CT), T1-weighted dual-echo magnetic resonance (MR) imaging, and point-resolved proton (hydrogen 1[(1)H]) MR spectroscopy in the assessment of hepatic steatosis in patients undergoing liver resection.

MATERIALS AND METHODS

This prospective study was approved by the institutional review board, and patients gave written informed consent. US, CT, T1-weighted MR imaging, and (1)H MR spectroscopy were performed preoperatively in 46 patients. Imaging results were correlated (Spearman correlation coefficient) with histopathologic analysis of results of intraoperative liver biopsies. To assess differences between groups, one-way analysis of variance was used. Sensitivity and specificity were calculated for each imaging modality by using receiver operating characteristic curve analysis, with a histopathologic cut-off value of 5% macrovesicular steatosis. Differences in sensitivity and specificity were assessed by means of McNemar analysis.

RESULTS

At histopathologic examination, 23 patients had no (0%-5%) macrovesicular steatosis, 11 had mild (5%-33%), nine had moderate (33%-66%), and three had severe (>66%). MR imaging and (1)H MR spectroscopic measurements of hepatic fat had stronger correlation with histopathologic steatosis assessment (r = 0.85, P < .001 and r = 0.86, P < .001, respectively) than did US (r = 0.66, P < .001) and CT (r = -0.55, P < .001). Only T1-weighted MR imaging and (1)H MR spectroscopy showed differences across steatosis grades: none versus mild (P = .001 for both), mild versus moderate (P < .001 for both), and moderate versus severe (P = .04 and .01, respectively). Sensitivity of US, CT, T1-weighted MR imaging, and (1)H MR spectroscopy was 65% (13 of 20), 74% (17 of 23), 90% (19 of 21), and 91% (21 of 23), respectively, and specificity was 77% (17 of 23), 70% (14 of 20), 91% (20 of 22), and 87% (20 of 23), respectively.

CONCLUSION

In contrast to US and CT, T1-weighted MR imaging and (1)H MR spectroscopy strongly correlate with histopathologic steatosis assessment and are able to demonstrate differences across steatosis grades. T1-weighted dual-echo MR imaging and (1)H MR spectroscopy had the best diagnostic accuracy in depicting hepatic steatosis.

The biopsied donor liver: incorporating macrosteatosis into high-risk donor assessment

To expand the donor liver pool, ways are sought to better define the limits of marginally transplantable organs. The Donor Risk Index (DRI) lists 7 donor characteristics, together with cold ischemia time and location of the donor, as risk factors for graft failure. We hypothesized that donor hepatic steatosis is an additional independent risk factor. We analyzed the Scientific Registry of Transplant Recipients for all adult liver transplants performed from October 1, 2003, through February 6, 2008, with grafts from deceased donors to identify donor characteristics and procurement logistics parameters predictive of decreased graft survival. A proportional hazard model of donor variables, including percent steatosis from higher-risk donors, was created with graft survival as the primary outcome. Of 21,777 transplants, 5051 donors had percent macrovesicular steatosis recorded on donor liver biopsy. Compared to the 16,726 donors with no recorded liver biopsy, the donors with biopsied livers had a higher DRI, were older and more obese, and a higher percentage died from anoxia or stroke than from head trauma. The donors whose livers were biopsied became our study group. Factors most strongly associated with graft failure at 1 year after transplantation with livers from this high-risk donor group were donor age, donor liver macrovesicular steatosis, cold ischemia time, and donation after cardiac death status. In conclusion, in a high-risk donor group, macrovesicular steatosis is an independent risk factor for graft survival, along with other factors of the DRI including donor age, donor race, donation after cardiac death status, and cold ischemia time.

Identifying a targeted population at high risk for infections after liver transplantation in the MELD era

Impact of model for end-stage liver disease (MELD) scoring system on post-transplant infections and associated risk factors are unknown. Infections <90 d post-transplant were assessed in 277 consecutive liver transplant recipients from 1999 to 2008. "High-risk" factors for infections were pre-defined as MELD score >30, ICU stay >48 h prior to transplant, intraoperative transfusion ≥15 units, retransplantation, post-transplant dialysis, or reoperation. Of the 240 recipients in the MELD era (2002-2008), 48.5% had any high-risk factor. The OR for infection was 1.69, 2.00, 18.00, and 4.50 in recipients with any 1, 2, 3, and ≥4 high-risk factors, respectively (χ(2) for trend, p < 0.001). In logistic regression model, recipient age (OR 1.12, p < 0.05) and any high-risk factor (OR 2.42, p < 0.05) were associated with infections. Compared with 37 pre-MELD recipients, the overall infections and mortality at 12 months did not differ in the two eras. In Cox regression model, recipient age (OR 1.09, p < 0.05) and any high-risk factor (OR 2.42, p < 0.05) remained associated with infections. The overall frequency of infections did not increase in the MELD era. Pre-defined risk factors accurately predicted the risk of infections in these patients.

Non-alcoholic steatohepatitis induces non-fibrosis-related portal hypertension associated with splanchnic vasodilation and signs of a hyperdynamic circulation in vitro and in vivo in a rat model

INTRODUCTION

Steatosis, without fibrosis, may lead to changes in liver blood flow, which are poorly understood, and to date have not been correlated to portal pressure and related haemodynamics.

AIMS

To study the temporal relation between progressive steatosis, portal pressure, systemic haemodynamics, vascular responsiveness, mesenteric and portal blood flow in methionine-choline-deficient diet (MCDD)-fed rats.

METHODS

Male Wistar rats fed the MCDD were examined at week (w) 0-1-2-3-4-5-6-7-8, respectively, including systemic haemodynamics and portal pressure. At w0-4-8, in vivo blood flow was measured in the portal vein and the superior mesenteric artery. Dose-response curves to phenylephrine (PE) were established in abdominal aortic rings.

RESULTS

Histology showed 100% steatosis from w3 on. Fibrosis was absent. Significant inflammation was nearly absent upon w4. Portal pressure slightly increased at w2, reached a maximum at w4 [9.4 +/- 0.3 vs 2.9 +/- 0.6 mmHg at w0 (P=0.003)] and remained stable upon w8. Mean arterial blood pressure (MABP) decreased from w2 on [98.7 +/- 5.7 mmHg on w4 compared with 123.8 +/- 1.8 on w0 (P=0.002)]. Portal flow increased from 1.85 +/- 0.11 to 3.07 +/- 0.44 ml/min/100 g on w0 and w8 respectively (P=0.039). Mesenteric artery flow increased from 3.40 +/- 0.26 to 4.56 +/- 0.30 ml/min/100 g on w0 and w8 respectively (P=0.043). Vascular responsiveness to PE gradually decreased from 138 +/- 3% on w0 to 110 +/- 5% on w4 (P=0.013).

CONCLUSION

Steatohepatitis induces significant portal hypertension (PHT) in the absence of fibrosis, associated with an increase in mesenteric arterial and portal venous flow, arterial hyporesponsiveness to vasoconstrictors and a decrease in MABP, indicating the presence of splanchnic vasodilation and hyperdynamic circulation. These alterations resemble those seen in cirrhotic PHT.

Microvesicular liver graft steatosis as a risk factor of initial poor function in relation to suboptimal donor parameters

OBJECTIVE

We sought to examine the role of microvesicular graft steatosis in relation to donor parameters.

MATERIALS AND METHODS

We performed 269 consecutive orthotopic liver transplantations (OLT) between 2004 and 2006. Donor parameters of age, body mass index (BMI), intensive care unit (ICU) stay, hypotension, cardiac arrest, pressors, sodium concentration, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transpeptidase (GGT), bilirubin, and activated partial thromboplastin time (APTT), as well as the degree of microvesicular graft steatosis were collected into the study. The endpoint of the study was liver graft dysfunction (AST or ALT > 2500 IU/L or prothrombin index < 50% during the first 7 days after OLT).

RESULTS

The risk of initial poor function (IPF) at day 7 posttransplantation was significantly related to hepatic microvesicular steatosis (odds ratio [OR] = 1.38 per 1 SD = 9.3%; P < .021). Accounting for the influence of the other donor factors produced little change in the numerical values of relative risk: from 1.22 (following exclusion of GGT) to 1.46 (after elimination of the influence of bilirubin concentration). A 50% increased risk of IPF was equivalent to 12% of the extent of steatosis.

CONCLUSION

Microvesicular steatosis is a risk factor for early hepatic dysfunction after OLT.

Toll-like receptor 4 is a key mediator of murine steatotic liver warm ischemia/reperfusion injury

Steatotic donors are routinely rejected for transplantation because of their increased rate of primary nonfunction. These grafts are more sensitive to ischemia/reperfusion (I/R) during transplantation. Removal of endotoxin before reperfusion improves liver performance post-I/R. We hypothesize that the main modality of injury in steatotic livers is toll-like receptor 4 (TLR4) signaling. We fed 4-week-old control and TLR4-deficient (TLR4KO) mice a normal diet (ND) or a 60% high-fat diet (HFD) for 4 weeks to induce steatosis. Mice were subjected to total hepatic ischemia (35 minutes) and reperfusion (1 or 24 hours). Survival improved and liver pathology decreased at 24 hours in TLR4KO HFD animals compared to control HFD animals. An investigation of infiltrates showed that neutrophils and CD4+ cells were increased at 24 hours in control HFD animals, whereas TLR4KO HFD animals were similar to ND controls. Messenger RNA levels of interleukin 6 (IL-6), IL-12, and interferon gamma were elevated at 1 hour in control HFD animals, whereas TLR4KO HFD animals were similar to ND controls. IL-10 levels at 1 hour of reperfusion in control HFD and TLR4KO animals were decreased versus control ND animals. In conclusion, these improvements in liver function in TLR4KO HFD animals implicate TLR4 as a mediator of steatotic graft failure after I/R.

Donor livers with steatosis are safe to use in hepatitis C virus-positive recipients

Whether donor graft steatosis affects liver function and influences survival after liver transplantation is still open to debate. The aim of this study was to assess the impact of donor graft steatosis on long-term liver histology after liver transplantation. One hundred sixteen consecutive liver transplants were performed in 56 hepatitis C virus-positive (HCV+) patients and 60 HCV- patients who had protocol liver biopsies at 6, 12, 24, and 36 months after liver transplantation. Liver biopsies were obtained from all grafts. No steatosis was seen in 50.9% of the biopsies taken at the back table before implantation, whereas steatosis was mild in 39.6% of the samples and moderate/severe in 9.5% of the samples. In the 56 HCV+ recipients, fibrosis stage 3 was seen in 22.2% and stage 4 was seen in 2.2% of 45 biopsies at 36 months after liver transplantation. There was no correlation between donor graft steatosis and fibrosis after liver transplantation, regardless of the etiology of liver disease. No difference in 36-month survival after liver transplantation was seen, regardless of whether the etiology of the patient's liver disease was HCV-related or non-HCV-related (80.3% versus 75%; P = 0.4) and whether the steatosis in the graft was reportedly absent, mild, or moderate/severe (79.7% versus 73.9% versus 81.1%; P = 0.7). In conclusion, nearly one-quarter of HCV+ recipients have precirrhosis/cirrhosis 3 years after liver transplantation. Steatotic grafts do not seem to exacerbate the progression of fibrosis in HCV+ recipients, nor do they seem to negatively affect 3-year patient survival.

Variable activation of phosphoinositide 3-kinase influences the response of liver grafts to ischemic preconditioning

BACKGROUND/AIMS

The efficacy of ischemic preconditioning (IPC) in preventing reperfusion injury in human liver transplants is still questioned. Phosphoinositide-3-kinase (PI3K) is essential for IPC development in rodent livers. This work investigates whether PI3K-dependent signals might account for the inconsistent responses to IPC of transplanted human livers.

METHODS

Forty livers from deceased donors were randomized to receive or not IPC before recovery. PI3K activation was evaluated in biopsies obtained immediately before IPC and 2 h after reperfusion by measuring the phosphorylation of the PI3K downstream kinase PKB/Akt and the levels of the PI3K antagonist phosphatase tensin-homologue deleted from chromosome 10 (PTEN).

RESULTS

IPC increased PKB/Akt phosphorylation (p = 0.01) and decreased PTEN levels (p = 0.03) in grafts, but did not significantly ameliorate post-transplant reperfusion injury. By calculating T(2h)/T(0) PKB/Akt phosphorylation ratios, 10/19 (53%) of the preconditioned grafts had ratios above the control threshold (IPC-responsive), while the remaining nine grafts showed ratios comparable to controls (IPC-non-responsive). T(2h)/T(0) PTEN ratios were also decreased (p < or = 0.03) only in IPC-responsive grafts. The patients receiving IPC-responsive organs had ameliorated (p < or = 0.05) post-transplant aminotransferase and bilirubin levels, while prothrombin activity was unchanged.

CONCLUSIONS

Impaired PI3K signaling might account for the variability in the responses to IPC of human grafts from deceased donors.

Successful use of extended criteria donor grafts with low to moderate steatosis in patients with model for end-stage liver disease scores below 27

Liver transplantation may be performed using extended criteria donor grafts (ECDg). The characteristics of ECDg include age >60 years, long intensive care unit (ICU) stay, history of malignancy or steatosis. Grafts are often discarded due to steatosis, which can be macrovesicular (MaS) or microvesicular (MiS). MaS is the variety most frequently involved with unfavorable outcomes due to primary nonfunction (PNF) or primary dysfunction (PDF). As of January 2000, all livers referred to our institution were considered potentially transplantable. Steatosis was defined as the presence of fat droplets in more than 5% of hepatocytes. We observed 35 steatotic grafts. Grafts were stratified according to MaS and MiS as follows: low steatosis (5%-15%), mild steatosis (16%-30%), moderate steatosis (31%-60%), or severe steatosis (>60%). Fifteen grafts with moderate (n = 2) or severe (n = 13) MaS were discarded. Twenty grafts were harvested: 18 of them were transplanted at our institution, the remaining 2, discarded by our donor team, were transplanted by other Italian centers. Low MaS was detected in 10 grafts (50%), mild MaS in 4 (20%), and moderate MaS in 2 (10%). Low MiS was detected in 8 grafts (40%), mild MiS in 5 (25%), and moderate MiS in 1 (5%). Steatotic grafts were transplanted only into recipients with model for end-stage liver disease (MELD) scores <27. The 6-month graft survival was 80%; the PNF rate was 10%; and the PDF rate was 15%. The careful use of ECDg with low to moderate steatosis is possible if particular care is taken to avoid additional risk factors related to the recipient.

Biological changes after liver transplantation according to the presence or not of graft steatosis

AIM

To assess the consequences of graft steatosis on postoperative liver function as compared with normal liver grafts.

PATIENTS AND METHODS

From January 2005 to December 2007, liver transplant patients were prospectively included, excluding those who experienced arterial or biliary complications or presented acute rejection. All patients had a surgical biopsy after reperfusion. Patients were compared according to the rate of macrovacuolar steatosis: namely above or below 20%.

RESULTS

Fifty-three patients were included: 10 in the steatosis group and 43 in the control group. No significant difference was observed in terms of morbidity, mortality, and primary non- or poor function. Nevertheless, biological changes after the procedure were significantly different during the first postoperative week. Prothrombin time, serum bilirubin, and transaminases were significantly increased among the steatosis group compared with the control group (P < .05).

CONCLUSION

This case-controlled study including a small number of patients, described postoperative biological changes among liver transplantations with steatosis in the graft.

D-MELD, a simple predictor of post liver transplant mortality for optimization of donor/recipient matching

Numerous donor and recipient risk factors interact to influence the probability of survival after liver transplantation. We developed a statistic, D-MELD, the product of donor age and preoperative MELD, calculated from laboratory values. Using the UNOS STAR national transplant data base, we analyzed survival for first liver transplant recipients with chronic liver failure from deceased after brain death donors. Preoperative D-MELD score effectively stratified posttransplant survival. Using a cutoff D-MELD score of 1600, we defined a subgroup of donor-recipient matches with significantly poorer short- and long-term outcomes as measured by survival and length of stay (LOS). Avoidance of D-MELD scores above 1600 improved results for subgroups of high-risk patients with donor age >/=60 and those with preoperative MELD >/=30. D-MELD >/=1600 accurately predicted worse outcome in recipients with and without hepatitis C. There is significant regional variation in average D-MELD scores at transplant, however, regions with larger numbers of high D-MELD matches do not have higher survival rates. D-MELD is a simple, highly predictive tool for estimating outcomes after liver transplantation. This statistic could assist surgeons and their patients in making organ acceptance decisions. Applying D-MELD to liver allocation could eliminate many donor/recipient matches likely to have inferior outcome.

Impact of donor graft steatosis on overall outcome and viral recurrence after liver transplantation for hepatitis C virus cirrhosis

The aim of this study was to determine the influence of donor graft steatosis on overall outcome, viral recurrence, and fibrosis progression in orthotopic liver transplantation (OLT) for hepatitis C virus (HCV) cirrhosis. One hundred twenty patients who underwent OLT for HCV cirrhosis between 1995 and 2005 were included in the study. Donor steatosis was categorized as absent (0%-10%; n = 40), mild (10%-30%; n = 32), moderate (30%-60%; n = 29), or severe (>60%; n = 19). A Cox multivariate analysis for marginal donor variables and a Model for End-Stage Liver Disease index were performed. Fibrosis evolution was analyzed in liver biopsies (fibrosis < 2 or > or =2) 3, 6, and 12 months post-OLT and in the late post-OLT period. Fifty-six grafts were lost (46%). The survival of the grafts was inversely proportional to donor liver steatosis: 82%, 72%, and 72% at 1, 2, and 3 years post-OLT in the absence of steatosis; 73%, 63%, and 58% with mild steatosis; 74%, 62%, and 43% with moderate steatosis; and 62%, 49%, and 42% with severe steatosis (P = 0.012). HCV recurrence was earlier and more frequent in recipients with steatosis > 30% (46% versus 32% at 3 months, P = 0.017; 58% versus 43% at 6 months, P = 0.020; 70% versus 56% at 12 months, P = 0.058; and 95% versus 69% at 3 years post-OLT, P = 0.0001). Graft survival was lower in alcoholic liver disease recipients versus HCV recipients when steatosis was >30% at 3, 6, and 12 months post-OLT (P = 0.042) but not when steatosis was <30% (P = 0.53). A higher fibrosis score was obtained 3 months post-OLT (P = 0.033), 6 months post-OLT (P = 0.306), 12 months post-OLT (P = 0.035), and in the late post-OLT period (P = 0.009). In conclusion, donor graft steatosis influences the outcome of OLT for HCV cirrhosis. HCV recurrence is more frequent and earlier in recipients of moderately and severely steatotic livers. Fibrosis evolution is higher when graft steatosis is >30%. OLT with >30% steatotic donor livers should be precluded in HCV recipients.

National Organ Retrieval Imaging System: results of the pilot study

Efficient utilization of marginal liver grafts is dependant on the accurate assessment and relay of graft-related information to recipient units in an organ-sharing network. Currently, information is conveyed by the recovery team over the telephone and can sometimes be inconclusive or incomplete. We have developed a web-based instrument called the National Organ Retrieval Imaging System (NORIS) to improve this assessment process. The aim of this pilot study was to assess the feasibility of real-time data upload and the reliability of web-based remote assessment in identifying donor livers with significant macro-steatosis. Data from 153 donor livers uploaded to the website were analysed. Completeness of graft data uploads, accuracy of on-site and two separate remote assessments using a semi-objective graft score in identifying grafts with moderate or severe macro-vesicular steatosis were analysed. Uploads were complete in all recoveries. Liver grafts with moderate or severe macro-vesicular steatosis had a higher incidence of initial poor function (7/10 vs. 26/86, P = 0.029). Organ scores for steatotic grafts were significantly higher than nonsteatotic grafts in all three assessments (P < 0.001). Accuracy of the two remote assessors was similar to the actual on-site assessment. There was a substantial degree of inter-observer agreement between the assessments (kappa statistics = 0.658, 0.597, 0.698). Feasibility of real-time data upload and reliability of remote graft assessment have been confirmed.

Report of the Paris consensus meeting on expanded criteria donors in liver transplantation

Because of organ shortage and a constant imbalance between available organs and candidates for liver transplantation, expanded criteria donors are needed. Experience shows that there are wide variations in the definitions, selection criteria, and use of expanded criteria donors according to different geographic areas and different centers. Overall, selection criteria for donors have tended to be relaxed in recent years. Consensus recommendations are needed. This article reports the conclusions of a consensus meeting held in Paris in March 2007 with the contribution of experts from Europe, the United States, and Asia. Definitions of expanded criteria donors with respect to donor variables (including age, liver function tests, steatosis, infections, malignancies, and heart-beating versus non-heart-beating, among others) are proposed. It is emphasized that donor quality represents a continuum of risk rather than "good or bad." A distinction is made between donor factors that generate increased risk of graft failure and factors independent of graft function, such as transmissible infectious disease or donor-derived malignancy, that may preclude a good outcome. Updated data concerning the risks associated with different donor variables in different recipient populations are given. Recommendations on how to safely expand donor selection criteria are proposed.

The marginal liver donor--an update

The number of patients awaiting liver transplantation keeps steadily rising with no corresponding rise in suitable grafts for transplantation. There also is an increasing trend of patients dying or being taken off waiting lists because of deterioration while waiting for a transplant. Over the preceding years the use of marginal grafts in liver transplantation has been driven by the critical shortage of donor organs and by emerging data that their use has resulted in a favourable outcome. This review revisits the factors defining marginality of a graft, and the issues faced by transplant units in making the decision to use such a graft. It also looks at the innovations in transplantation geared towards increasing the donor pool and the resulting issues of matching marginal grafts to suitable recipients.

Utility of liver allograft biopsy obtained at procurement

Extended-donor criteria (EDC) liver allografts potentiate the role of procurement biopsy in organ utilization. To expedite allocation, histologic evaluation is routinely performed upon frozen-section (FS) specimens by local pathologists. This descriptive study compares FS reports by local pathologists with permanent-section (PS) evaluation by dedicated hepatopathologists, identifies histologic characteristics underrepresented by FS evaluation, and evaluates the efficacy of a biopsy decision analysis based on organ visualization. Fifty-two liver transplants using EDC allografts evaluated by FS with PS were studied. Pathologic worksheets created by an organ procurement organization were applied in 34 FS. PS analysis included 7 staining procedures for 8 histologic criteria. PS from 56 additional allografts determined not to require donor biopsy were also analyzed. A high correlation was observed between FS and PS. Underestimation of steatosis by FS was associated with allograft dysfunction. Surgical assessment of cholestasis, congestion, and steatosis was accurate whereas inflammation, necrosis, and fibrosis were underestimated in allografts suffering parenchymal injury. In conclusion, the correlation between FS and PS is high, and significant discrepancies are rare. Biopsy is not a prerequisite for EDC utilization but is suggested in hepatitis C, hypernatremia, donation after cardiac death, or multiple EDC indications. Implementation of a universal FS worksheet could standardize histologic reporting and facilitate data collection, allocation, and research.

Effect of graft steatosis on liver function and organ survival after liver transplantation

BACKGROUND

It was the aim to determine the effect of graft steatosis on intraoperative organ blood flow, postoperative liver function, and organ survival.

METHODS

A total of 225 consecutive liver transplants were reviewed. Liver blood flow, hepatic function (AST, ALT, prothrombin time), and organ survival were determined. Donor liver grafts were categorized into 2 subgroups: mild (<30%) (n = 175) and moderate to severe (>/=30%) (n = 50) macrovesicular steatosis.

RESULTS

Moderate to severe steatosis was associated with significantly increased AST and ALT levels and significantly diminished prothrombin time on the first and second postoperative day. By day 7 differences in liver function were no longer evident. Organ blood flow was not affected by steatosis. After adjustment for potential confounders, organ survival did not depend on the degree of donor steatosis (5-year-survival rates: 68% and 58% with steatosis <30%, or >/= 30%, respectively) (hazard ratio .754, confidence interval .458-1.242, P = .268).

CONCLUSION

Steatotic livers can be transplanted safely with good results for long-term organ survival if other contraindications are absent.

Use of severely steatotic grafts in liver transplantation: a matched case-control study

BACKGROUND

Although there is a worldwide need to expand the pool of available liver grafts, cadaveric livers with severe steatosis (>60%) are discarded for orthotopic liver transplantation (OLT) by most centers.

METHODS

We analyzed patients receiving liver grafts with severe steatosis between January 2002 and September 2006. These patients were matched 1:2 with control patients without severe steatosis according to status the waiting list, recipient age, recipient body mass index (BMI), and model for end-stage liver disease (MELD) score. Primary end points were the incidence of primary graft nonfunction (PNF), and graft and patient survival. Secondary end points included primary graft dysfunction (PDF), the incidence of postoperative complications, and histologic assessment of steatosis in follow-up biopsies. We also conducted a survey on the use of grafts with severe steatosis among leading European liver transplant centers.

RESULTS

During the study period, 62 patients dropped out of the waiting list and 45 of them died due to progression of disease. Of 118 patients who received transplants 20 (17%) received a graft with severe steatosis during this period. The median degree of total liver steatosis was 90% (R = 65%-100%) for the steatotic group. The steatotic (n = 20) and matched control group (n = 40) were comparable in terms of recipient age, BMI, MELD score, and cold ischemia time. The steatotic group had a significantly higher rate of PDF and/or renal failure. Although the median intensive care unit (ICU) and hospital stay were not significantly different between both groups, the proportion of patients with long-term ICU (> or =21 days) and hospital (> or =40 days) stay was significantly higher for patients with a severely steatotic graft. Sixty-day mortality (5% vs. 5%) and 3-year patient survival rate (83% vs. 84%) were comparable between the control and severe steatosis group. Postoperative histologic assessment demonstrated that the median total amount of liver steatosis decreased significantly (median: 90% to 15%, P < 0.001). Our survey showed that all but one of the European centers currently reject liver grafts with severe steatosis for any recipient.

CONCLUSION

Due to the urgent need of liver grafts, severely steatotic grafts should be no longer discarded for OLT. Maximal effort must be spent when dealing with these high-risk organs but the use of severely steatotic grafts may save the lives of many patients who would die on the waiting list.

Does donor's fatty liver change impact on early mortality and outcome of liver transplantation

BACKGROUND

The effect of donor fatty liver on graft survival is still uncertain. The aim of this study was to determine the influence of steatosis on the outcomes of OLT among our recipients.

METHODS

In this retrospective study, we evaluated the effect of donor liver steatosis on postoperative liver function and prognosis. Data obtained from liver transplantation data registry of our organ transplant center. Liver biopsies taken before transplantation were reviewed by two pathologists. Pathology reports were divided into four groups: normal pathology; mild fatty change (10%-30%); moderate (30%-60%); and severe steatosis (>60%). Livers with severe steatosis were excluded from transplantation. Factors determining transplantation outcome, such as early mortality, duration of intensive care unit (ICU) and hospital stay, clinical rejection episodes, and graft surgical complications, were compared between subjects who received donor liver, with various degrees of steatosis.

RESULTS

Three-month survival rates in recipients without donor liver fatty change, subjects with mild fatty change (10%-30%) and those with moderate (30%-60%) steatosis were 68%, 72%, and 76%, respectively, which were not significantly different (P>.05). Furthermore, short-term (hospital) mortality (20%, 14.3%, and 21.2%), hospital stay (30.89, 29.93, and 23.62 days), and length of ICU admission (5.06, 5.89, and 4.39 days) were not significantly different. In addition, Child score of recipients, pre- and postoperative liver function enzyme changes were similar.

CONCLUSION

Mild-to-moderate (up to 60%) liver fatty change was not found to be associated with a worse prognosis in OLT.

Unenhanced CT for assessment of macrovesicular hepatic steatosis in living liver donors: comparison of visual grading with liver attenuation index

PURPOSE

To retrospectively compare the accuracy of visual grading and the liver attenuation index in the computed tomographic (CT) diagnosis of 30% or higher macrovesicular steatosis in living hepatic donors, by using histologic analysis as the reference standard.

MATERIALS AND METHODS

Institutional review board approval was obtained with waiver of informed consent. Of 703 consecutive hepatic donor candidates, 24 patients (22 men and two women; mean age +/- standard deviation, 36.3 years +/- 9.7) who had 30% or higher macrovesicular steatosis at histologic analysis and same-day CT with subsequent needle biopsy in the right hepatic lobe (at least two samples per patient) were evaluated. An age- and sex-matched control group of 24 subjects included those who had less than 30% macrovesicular steatosis but otherwise met the same criteria as the patient group. A diagnostically difficult setting was made by selecting those with the highest degree of macrovesicular steatosis when there were multiple control subjects matched for a particular subject in the patient group. Two independent radiologists assessed steatosis of the right hepatic lobe by using two methods: a five-point visual grading system that used attenuation comparison between the liver and hepatic vessels and the liver attenuation index (CT(L-S)), defined as hepatic attenuation minus splenic attenuation and calculated with region of interest measurements of hepatic attenuation. Interobserver agreement was assessed. Accuracy in the diagnosis of 30% or higher macrovesicular steatosis was compared by using a multireader, multicase receiver operating characteristic (ROC) analysis.

RESULTS

For visual grading, kappa = 0.905 (95% confidence interval [CI]: 0.834, 0.976). Intraclass correlation coefficient for CT(L-S) was 0.962 (95% CI: 0.893, 0.983). The area under the ROC curve of visual grading and CT(L-S) were 0.927 (95% CI: 0.822, 1) and 0.929 (95% CI: 0.874, 0.983), respectively, indicating no statistically significant difference (P = .975).

CONCLUSION

Both visual grading and CT(L-S) are highly reliable and similarly accurate in the diagnosis of 30% or higher macrovesicular steatosis in living hepatic donor candidates.

The response of the hepatocyte to ischemia

BACKGROUND

Ischemia-reperfusion (I/R) injury associated with hepatic resections and liver transplantation remains a serious complication in clinical practice, in spite of several attempts to solve the problem.

AIMS

To evaluate the response of the hepatocyte to ischemia

METHODS

Published data are thus revised.

RESULTS

The response of the hepatocyte to ischemia is based on the sensitivity of hepatocytes to different types of ischemia, the kind of cell death of the hepatocyte when it is subjected to ischemia, and on the response of the hepatocyte to the different times and extents of ischemia. Clinical factors including starvation, graft, age, and hepatic steatosis, all of which contribute to enhancing liver susceptibility to ischemia/reperfusion injury.

CONCLUSION

Ischemic preconditioning, based on the induction of a brief ischemia to the liver prior to a prolonged ischemia, has been applied in tumor hepatic resections for reducing hepatic I/R injury and recent clinical studies suggest that this surgical strategy could be appropriate for liver transplantation.

Impact of polysol, a newly developed preservation solution, on cold storage of steatotic rat livers

Chronic shortage of donor organs has led to acceptance of steatotic livers as grafts, although there is a higher risk of primary graft dysfunction. We herein report the beneficial impact of Polysol, a newly developed preservation solution, on cold storage of steatotic rat livers. Dietary hepatic steatosis was induced in Wistar rats by 2-day fasting and subsequent 3-day re-feeding with a fat-free, carbohydrate-rich diet. Fatty livers were retrieved, flushed and then stored at 4 degrees C for 24 hours with either HTK or Polysol. Functional integrity of the grafts was evaluated by isolated reperfusion with oxygenated Krebs-Henseleit buffer at 37 degrees C for 45 minutes in both groups. Polysol preservation resulted in significant reductions of not only parenchymal (AST (IU/L); 6728+/-824 in HTK vs. 3107+/-718 in Polysol; P < 0.001) but also mitochondrial (GLDH (IU/L); 3189+/-773 vs. 1282+/-365; P < 0.01) enzyme release throughout reperfusion. Moreover, PVP (16.9+/-2.7 vs. 7.8+/-1.5 mmHg; P < 0.05), hepatic O2 consumption (0.291+/-0.047 vs. 1.056+/-0.053 micromol/g liver/min; P < 0.001), tissue ATP content (0.695+/-0.086 vs. 1.340+/-0.157 micromol/g dry-liver; P < 0.005), bile production (0.79+/-0.11 vs. 4.08+/-0.66 microL/g liver/45-min; P < 0.001), malondialdehyde into the perfusate (1.922+/-0.198 vs. 0.573+/-0.094 nmol/L; P < 0.0001) and wet/dry-weight ratio of the liver tissues (5.20+/-0.31 vs. 3.85+/-0.15; P < 0.005) were all better preserved by Polysol. In line with these benefits, electron microscopy revealed that Polysol preservation substantially suppressed deleterious mitochondrial alterations in steatotic livers. In conclusion, cold storage using Polysol resulted in significantly better integrity and function of steatotic livers. Polysol, therefore, may be a new alternative especially for "marginal" organs.

Bacterial- and fungal-positive cultures in organ donors: clinical impact in liver transplantation

Infection transmission from donor to recipient is a dreadful complication in transplantation. Although bacteremia was previously detected in 5% of donors without negative impact on recipient outcome, the current expansion of graft pool requires consideration of the infectious risk associated with suboptimal donors. This study aims to evaluate the incidence and risk factors of infection in unselected cadaveric liver donors, the occurrence of microorganism transmission to recipient and its influence on patient survival. Results of microbiologic cultures obtained before harvesting in intensive care unit (ICU) and routinely at harvesting from 610 consecutive liver donors were retrospectively analyzed. Evidence for bacterial and fungal transmission to the recipient was searched for in each culture-positive donor. One or more cultures were positive in 293 donors (48%), while bacteremia was present in 128 (21%). Culture-positive and bacteremic donors were of significantly older age and had longer ICU stays. At multivariate analysis, an ICU stay of 3 or more days was the only significant predictor of donor infection. Although 1-year patient/graft survival rates were not influenced by donor culture positivity, pathogen transmission occurred in 11 cases with high recipient 1-year mortality (45%). In those 11 cases, median donor age was 74 years, significantly much older than that of the other culture-positive donors. In conclusion, donors with a prolonged ICU stay are at increased risk of infection, while older donor age is associated with pathogen transmission to the recipient. Adequate donor maintenance and careful microbiologic surveillance and treatment, especially of elderly donors, may limit transmission of donor infection.

The Role of Hepatic Biopsy to Detect Macrovacuolar Steatosis During Liver Procurement

The ability to predict graft function before transplantation has proven to be a difficult task, especially for macrovacuolar steatosis that is considered a major cause of posttransplant dysfunction. It is well known that macrovacuolar steatosis greater than 25% influences the short- and long-term outcomes of liver transplantation. We retrospectively analyzed frozen sections from 43 donor livers comparing preoperative laboratory/clinical values, and liver ultrasound of a cohort of donors without (group A, n=21) versus with steatosis of 25% to 35% (group B, n=22) upon liver biopsy performed during harvesting. We analyzed the possible correlations between preoperative donor data and the degree of macrovacuolar steatosis. None of the biochemical and clinical parameters were related to the degree of hepatic steatosis. The only difference between the two groups was the echographic pattern, with evidence of 27% fatty liver by ultrasound in group B and 5% in group A (p=.04). The specificity of hepatic ultrasound for macrovacuolar steatosis was 95% and the sensitivity was only 27%, while the positive and negative predictive value were 86% and 55%, respectively. In conclusion, liver biopsy during donor harvesting remains the gold standard to identify macrovacuolar steatosis greater than 25%. Hepatic ultrasound has a role to exclude the presence of steatosis in normal livers due to its high specificity, but it is not useful to make the diagnosis of a fatty liver since it has a low sensitivity and negative predictive value. Thereafter a liver ultrasound positive for hepatic steatosis alone should not be considered a valuable tool to discard an organ from transplantation.

The Marginal Donor: A Single-Center Experience in Orthotopic Liver Transplantation

The use of marginal donors has become more common worldwide due to the sharp increase in recipients with a consequent shortage of suitable organs. The definition of "marginal donor" has not been reached by all centers. We herein analyzed our single-center experience over the last 3 years in liver transplantation (OLT) to evaluate the outcomes of using a high percentage of so-called "marginal donors", according to the current classification from the National (Italian) Center of Transplantation (CNT). Among the 78 OLT performed in 77 patients from January 1, 2003 to October 31, 2005, donor livers were divided into three groups according to the CNT classification. We evaluated donor variables, cold ischemia time (CIT), warm ischemia time (WIT), MELD score, and length of hospital stay. Histologic graft steatosis was correlated with estimated steatosis by ultrasound. There were no differences among the three graft recipient groups concerning CIT, WIT, MELD score, and the length of hospital stay. Steatosis is indicated in all series as a definite variable for a higher risk of postoperative mortality. CIT is necessarily related to donor retrieval policy and organization. Donor age seemed also to be related to a possible increase in postoperative mortality, but there are significant variations in the definition of the age limit. We failed to observe a correlation between a higher mortality rate and any of the variables currently listed to define a "marginal donor." A shorter CIT seemed to positively influence the role played by the other variables identifying a "marginal liver." Finally, the use of HCV(+) or HBV(+) grafts did not lead to an increased mortality.

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

Transplant physicians and candidates have become increasingly aware that donor characteristics significantly impact liver transplantation outcomes. Although the qualitative effect of individual donor variables are understood, the quantitative risk associated with combinations of characteristics are unclear. Using national data from 1998 to 2002, we developed a quantitative donor risk index. Cox regression models identified seven donor characteristics that independently predicted significantly increased risk of graft failure. Donor age over 40 years (and particularly over 60 years), donation after cardiac death (DCD), and split/partial grafts were strongly associated with graft failure, while African-American race, less height, cerebrovascular accident and 'other' causes of brain death were more modestly but still significantly associated with graft failure. Grafts with an increased donor risk index have been preferentially transplanted into older candidates (>50 years of age) with moderate disease severity (nonstatus 1 with lower model for end-stage liver disease (MELD) scores) and without hepatitis C. Quantitative assessment of the risk of donor liver graft failure using a donor risk index is useful to inform the process of organ acceptance.

Effect of ischemic preconditioning in whole liver transplantation from deceased donors. A pilot study

The effect of ischemic preconditioning (IPC) in orthotopic liver transplantation (OLT) has not yet been clarified. We performed a pilot study to evaluate the effects of IPC in OLT by comparing the outcomes of recipients of grafts from deceased donors randomly assigned to receive (IPC+ group, n = 23) or not (IPC- group, n = 24) IPC (10-min ischemia + 15-min reperfusion). In 10 cases in the IPC+ group and in 12 in the IPC- group, the expression of inducible nitric oxide synthase (iNOS), neutrophil infiltration, and hepatocellular apoptosis were tested by immunohistochemistry in prereperfusion and postreperfusion biopsies. Median aspartate aminotransferase (AST) levels were lower in the IPC+ group vs. the IPC- group on postoperative days 1 and 2 (398 vs. 1,234 U/L, P = 0.002; and 283 vs. 685 U/L, P = 0.009). Alanine aminotransferases were lower in the IPC+ vs. the IPC- group on postoperative days 1, 2, and 3 (333 vs. 934 U/L, P = 0.016; 492 vs. 1,040 U/L, P = 0.008; and 386 vs. 735 U/L, P = 0.022). Bilirubin levels and prothrombin activity throughout the first 3 postoperative weeks, incidence of graft nonfunction and graft and patient survival rates were similar between groups. Prereperfusion and postreperfusion immunohistochemical parameters did not differ between groups. iNOS was higher postreperfusion vs. prereperfusion in the IPC- group (P = 0.008). Neutrophil infiltration was higher postreperfusion vs. prereperfusion in both groups (IPC+, P = 0.007; IPC-, P = 0.003). Prereperfusion and postreperfusion apoptosis was minimal in both groups. In conclusion, IPC reduced ischemia/reperfusion injury through a decrease of hepatocellular necrosis, but it showed no clinical benefits.

Macrovesicular hepatic steatosis in living liver donors: use of CT for quantitative and qualitative assessment

PURPOSE

To determine prospectively the diagnostic performance of unenhanced computed tomography (CT) in the assessment of macrovesicular steatosis in potential donors for living donor liver transplantation by using same-day biopsy as a reference standard.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained. A total of 154 candidates, including 104 men (mean age, 30.2 years +/- 10.3 [standard deviation]) and 50 women (mean age, 31.8 years +/- 11.2), underwent same-day unenhanced CT and ultrasonography-guided liver biopsy. Histologic degree of macrovesicular steatosis was determined. Three liver attenuation indices were derived: liver-to-spleen attenuation ratio (CT(L)(/S)), difference between hepatic and splenic attenuation (CT(L)(-S)), and blood-free hepatic parenchymal attenuation (CT(LP)). Regression equations were used to quantitatively estimate the degree of macrovesicular steatosis. Limits of agreement between estimated macrovesicular steatosis and the reference standard were calculated. Receiver operating characteristic analyses were used to determine the performance of each index for qualitative diagnosis of macrovesicular steatosis of 30% or greater. The cutoff value that provided a balance between sensitivity and specificity and the highest cutoff value that yielded 100% specificity were determined.

RESULTS

Limits of agreement were -14% to 14% for CT(L)(/S) and CT(L)(-S) and -13% to 13% for CT(LP). Performance in diagnosing macrovesicular steatosis of 30% or greater was not significantly different among indices (P > .05). Cutoff values of 0.9, -7, and 58 were determined for CT(L)(/S), CT(L)(-S), and CT(LP), respectively, and provided a balance between sensitivity and specificity. Cutoff values of 0.8, -9, and 42 were determined for CT(L)(/S), CT(L)(-S), and CT(LP), respectively, and yielded 100% specificity for all indices, with corresponding sensitivities of 82%, 82%, and 73% for CT(L)(/S), CT(L)(-S), and CT(LP), respectively.

CONCLUSION

Diagnostic performance of unenhanced CT for quantitative assessment of macrovesicular steatosis is not clinically acceptable. Unenhanced CT, however, provides high performance in qualitative diagnosis of macrovesicular steatosis of 30% or greater.

Practice of adult liver transplantation in Italy. Recommendations of the Italian Association for the Study of the Liver (A.I.S.F.)

Liver transplantation is an efficient procedure as performed in Italy, yet major differences are present in terms of practice. In an effort to facilitate an homogeneous practice of liver transplantation in Italy, the Italian Association for the Study of Liver Disease has instituted a Commission aimed at providing recommendations on non-urgent liver transplantation in adults, based on current evidence. This nation-wide commission which included experienced hepatologists, surgeons and pathologists with major interest in liver transplantation has drafted a final document in October 2004, approved by the Italian Association for the Study of Liver Governing Board, whose key arguments and main conclusions are summarised in the present paper. The Commission has made specific recommendations on the following topics: the current needs of liver transplantation in Italy; the indications to liver transplantation and re-liver transplantation, with special reference to controversial issues and the minimal listing criteria; the use of marginal donors and the need to optimise donor/recipient matching; the use of living donor liver transplantation; the management of the waiting list and the introduction of Model for End-Stage Liver Disease to define priorities; the clinical management of liver transplantation recipients and disease recurrence; the implementation of audits and outcome monitoring; the training of transplant surgeons and hepatologists and the requirements for Centre accreditation; the pathology of liver transplantation.

Factors affecting graft survival after living donor liver transplantation

Living donor liver transplantation (LDLT) has been considered as an alternative option to resolve the shortage of cadaveric donor organs, despite the ethical aspects of the donor procedure. The objective of this study was to analyze the risk factors affecting graft survival in LDLT. From June 1996 to December 2002, 141 patients who underwent LDLT were retrospectively analyzed. Graft survival rates were 82.5%, 80%, 77.3%, and 77.3% at 6 months, 1 year, 3 years, and 5 years, respectively. The factors influencing graft survival in univariate analysis were graft-to-recipient body weight ratio (GRWR) less than 0.8% (P = .0009), intraoperative transfusion of more than six packed RBC units in addition to the use of cell saver amounts (P = .0001), left lobe grafts in adults causing small-for-size situations (P = .0135), and donor age (P = .0472). The multivariate analysis demonstrated that GRWR less than 0.8% (P = .002) and intraoperative transfusion of more than six packed RBC units (P = .014) were independent factors that decreased graft survival rates. The graft selection of greater than 0.8% of GRWR and reduction of intraoperative RBC transfusion improve graft survival.

Noninvasive evaluation of graft steatosis in living donor liver transplantation

BACKGROUND

Hepatic steatosis affects graft function as well as postoperative recovery of donors in living donor liver transplantation. Liver macrovesicular steatosis in living donors was assessed using quantitative X-ray computed tomography (CT) analysis and histological examination of intraoperative liver biopsy.

METHODS

A total of 266 living donors with complete pretransplant CT data and intraoperative "time 0" biopsy were included in the study. Liver biopsy specimen obtained during donor operation was examined for macrovesicular steatosis and was classified as none; mild (<30%); moderate (30%-60%); or severe (>60%). Liver-to-spleen CT attenuation values ratio (L/S ratio) on noncontrast-CT was evaluated for its usefulness as an index of hepatic steatosis in comparison with other parameters including body mass index (BMI) and serum liver function tests (gamma-glutamyl transpeptidase, alanine aminotransferase, aspartate aminotransferase, cholinesterase, and total cholesterol) using receiver operating characteristic (ROC) analysis. RESULTS.: Histological grade of macrovesicular steatosis was none in 198 patients (74.4%), mild in 50 (18.8%), moderate in 15 (5.7%), and severe in 3 (1.1%). The median L/S ratios for the respective histological grades were 1.20 (range: 1.00-1.46), 1.12 (0.83-1.37), 1.01 (0.74-1.21), and 0.90 (0.70-0.99) (P<0.0001). The ROC curve for L/S ratio was located closest to the upper left corner, and the area under the curve of L/S ratio was significantly larger than that of any other preoperative variables.

CONCLUSION

L/S ratio calculated from preoperative CT can be a useful tool to discriminate hepatic macrovesicular steatosis. Based on the present results, the optimal cut-off value for L/S ratio to exclude more than moderate steatosis would be 1.1.

Morphometric analysis of primary graft non-function in liver transplantation

AIMS

Primary graft non-function (PNF) is a life-threatening condition that is thought to be the consequence of microcirculation injury. The aim of the present study was to assess, with a computerized morphometric model, the morphological changes at reperfusion in liver biopsy specimens from patients who developed PNF after liver transplantation.

METHODS AND RESULTS

Biopsy specimens were obtained at maximum ischaemia and at the end of reperfusion. Morphology included many stereological parameters, such as volumes of all parenchymal components, surface density, size distribution and mean diameter of hepatocytes. Other variables examined were intensive care unit stay, degree of steatosis, serum liver function tests and ischaemic time. In the postoperative period, the PNF group showed elevated serum levels of alanine transferase, decreased daily rate of bile production and prothrombin activity. Blood lactates were significantly higher in the PNF group than in a control group. When comparing groups, the volumetric parameters related to hepatocytes and sinusoids and the surface densities of the hepatic cells showed an inverse relationship. At the end of reperfusion, in PNF group the volume fraction of hepatocyte cytoplasm was decreased; in contrast, the volume fraction of sinusoidal lumen was markedly increased. The cell profiles showed the same inverse trend: the surface density of the parenchymal border of hepatocytes was decreased in PNF when compared with the control group, while the surface density of the vascular border was increased. In the PNF group, the surface density of the sinusoidal bed was directly correlated with alanine transferase, daily rate of bile production, prothrombin activity and cold ischaemic time.

CONCLUSIONS

The alterations in hepatic architecture, as demonstrated by morphometric analysis in liver transplant recipients that developed PNF, provide additional information that may represent useful viability markers of the graft to complement conventional histological analysis.

Surgical advances in liver and bowel transplantation

Liver and intestinal transplantation are currently the treatments of choice for life-threatening hepatic and gastrointestinal failure. These technologies have evolved through contributions from the fields of immunology, anatomy, physiology, surgery, anesthesiology, critical care, ethics, epidemiology, and public health. Transplantation now accounts for the treatment of over 5,000 recipients per year who are in a state of organ failure. The available donor population, however, is not increasing to meet the demands of the faster growing recipient population. This discrepancy has led to the rapid development of novel strategies that require critical evaluation to build on the success rates in recent years. This article presents the most salient advances in liver and intestinal transplantation in the last 15 years.

Absence of impact of donor hepatic steatosis and posttransplantation lamivudine resistance in a patient with chronic hepatitis B

A patient with chronic hepatitis B underwent liver transplantation for end-stage cirrhosis. The donor liver graft had moderate steatosis and fibrosis. He was placed on lamivudine for hepatitis B prophylaxis but developed viral relapse due to emergence of a lamivudine-resistant mutant at week 72 posttransplantation. Results of liver biochemistry were normal liver histology revealed minimal steatosis and inflammation at weeks 151 and 128, respectively. This report illustrates that the use of a steatotic donor liver and the emergence of lamivudine resistance posttransplantation are not necessarily associated with significant graft damage. A marginal donor graft can be considered due to the donor shortage. Lamivudine monoprophylaxis for hepatitis B virus-related liver diseases post liver transplantation can be used in areas where hepatitis B immunoglobulin is not affordable.

Excellent outcome following transplantation of a domino donor liver with high-grade macrosteatosis

Severe macrosteatosis in the donor liver is considered a major predictive factor of primary graft non-function. Such livers are usually discarded despite an ever-growing need for donor livers. We report our recent experience in a patient (#1) who had an excellent outcome following liver transplantation (LT) of a 65-70% macrosteatotic graft and compare his findings with those of two other (#2 and #3) recipients of moderate to severe macrosteatotic grafts. Both patients (#2 and #3) had initial diminished function, with recovery in patient #2 but delayed graft non-function requiring re-LT (day 24) in patient #3. Patient #1 had no intra-operative complications, while patient #2 had mild complications due to prior adhesions and graft capsular laceration. In patient #3, extensive intra-abdominal adhesions resulting in excessive bleeding occurred during recipient hepatectomy. Total ischemic times: 2.48, 6.10, and 8.18 h; total blood product usage: 43, 81, and 223 units; post-LT hospital stay: 9, 21, and 69 days were seen in patients #1, #2 and #3, respectively. In conclusion, post-LT excellent graft function was seen in one recipient of 65-70% macrosteatotic graft. Transplantation of grafts with moderate/severe macrosteatosis may be inadvisable in patients with extensive intra-abdominal adhesions with expectant excessive bleeding and long ischemia times.

Therapeutic potential of interleukin-6 in preventing obesity- and alcohol-associated fatty liver transplant failure

Donor organ shortage significantly hinders orthotopic liver transplantation therapy, the only effective treatment for chronic end-stage liver disease and acute liver failure. Further complicating this matter is the prevalence of steatosis in 13% to 50% of donor livers obtained from obese and alcoholic individuals. When transplanted, these livers are associated with primary nonfunction and an elevated risk of dysfunction. New therapeutic approaches to render marginal fatty livers worthy for clinical transplantation are actively being sought. Study findings obtained from my group show that in vitro treatment with interleukin-6 (IL-6) dramatically reduces mortality, liver injury, and necrapoptosis in steatotic Zucker rat liver isografts. Findings of additional studies indicate that IL-6 induces hepatoprotection of steatotic liver isografts by preventing sinusoidal endothelial cell damage and, consequently, the amelioration of hepatic microcirculation, and by protecting against hepatocyte death, which is likely mediated through activation of signal transducer and activator of transcription 3/Bcl-x(L). Finally, in vitro IL-6 treatment also prevents mortality associated with alcoholic fatty liver transplants. Relative to the protective effect of IL-6 on steatotic Zucker rat liver, IL-6 is less effective in alcoholic fatty livers, which may be due to the inhibitory effects of ethanol on IL-6 activation of signal transducer and activator of transcription 3 in hepatocytes and sinusoidal endothelial cells. Collectively, these results support the assertion that in vitro IL-6 treatment of steatotic livers may render allografts usable for clinical transplantation, thereby decreasing the gap between the short supply of cadaver liver allografts and high demands for replacement livers. Higher concentrations of IL-6 may be required to protect against alcoholic fatty liver isograft injury because alcohol inhibits IL-6 signaling in the liver.