Causes of early acute graft failure after liver transplantation: analysis of a 17-year single-centre experience

Early Graft Loss With Suspected Seventh-Day Syndrome Following Pediatric Liver Transplantation

INTRODUCTION

Allograft dysfunction within the first week posttransplant is an uncommon but known complication following liver transplantation. Seventh-Day Syndrome (7DS) is a rare complication of allograft dysfunction following liver transplantation characterized by the rapid clinical deterioration of a formerly well-functioning allograft within the first week posttransplant. The etiology of 7DS is unknown, and treatment options remain limited. While cases of graft survival have been reported, the risk of mortality remains exceedingly high without urgent retransplantation.

METHODS

Patient data was retrospectively analyzed and a literature review performed.

RESULTS

We present a unique case of split liver transplantation into two pediatric recipients in which one recipient developed rapidly progressive graft failure approximately 1 week postoperatively requiring urgent retransplantation while the other recipient had an unremarkable postoperative course. Upon clinical manifestation of progressive graft failure, the patient was treated with thymoglobulin, rituximab, intravenous immunoglobulin, and plasmapheresis. Despite this, the patient's clinical status continued to decline and she underwent retransplantation 11 days following her initial liver transplant.

CONCLUSION

Seventh-Day Syndrome is a rare complication following liver transplantation that is associated with a high risk of morbidity and mortality. Our case adds to the limited literature on 7DS in children and is the first to report a comparative posttransplant clinical course in two recipients who received split grafts from the same donor.

Short-Term and Long-Term Effects of Ischemic Conditioning on Liver Transplantation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Although liver transplantation (LT) is one of the definitive treatments for patients with end-stage liver failure, it inevitably results in ischemic reperfusion injury. It is known that prognosis is improved when temporary ischemic conditioning (IC) is applied to patients with ischemic reperfusion injury. The objective of this meta-analysis was to determine the short-term and long-term effects of IC on the clinical outcomes of LT recipients.

METHODS

Randomized controlled studies on IC in patients with LTs were included. Patients were compared between an IC group and a sham group. Studies were retrieved from PubMed, Embase, and Cochrane Library. The risk of bias was evaluated using RoB 2.0. Mortality, graft function, and major complications were synthesized using RevMan 5.4.1.

RESULTS

Among 316 papers, 17 articles (1196 patients) were included. There was an insignificant increase in short-term mortality (risk ratio [RR]: 3.00, 95% CI: 0.32-28.14, P = .34). However, long-term mortality was lower in the IC group than in the sham group, but not significantly (RR: 0.75; 95% CI: 0.47-1.20, P = .23). Short-term graft function (acute graft rejection and primary graft non-function) was not improved by IC. One-year graft loss tended to show better results in the IC group (RR: 0.53, 95% CI: 0.26-1.07, P = .08).

CONCLUSION

Ischemic conditioning did not have a beneficial effect on LT. Although long-term outcomes appear to be better in the IC group than in the sham group, further randomized controlled trials are needed.

Endogenous Interleukin-33 Acts as an Alarmin in Liver Ischemia-Reperfusion and Is Associated With Injury After Human Liver Transplantation

Ischemia and reperfusion injury is an early inflammatory process during liver transplantation that impacts on graft function and clinical outcomes. Interleukin (IL)-33 is a danger-associated molecular pattern involved in kidney ischemia/reperfusion injury and several liver diseases. The aims were to assess whether IL-33 was released as an alarmin responsible for ischemia/reperfusion injury in a mouse model of warm hepatic ischemia, and whether this hypothesis could also apply in the setting of human liver transplantation. First, a model of warm hepatic ischemia/reperfusion was used in wild-type and IL-33–deficient mice. Severity of ischemia/reperfusion injury was assessed with ALT and histological analysis. Then, serum IL-33 was measured in a pilot cohort of 40 liver transplant patients. Hemodynamic postreperfusion syndrome, graft dysfunction (assessed by model for early allograft scoring >6), renal failure, and tissue lesions on time-zero biopsies were assessed. In the mouse model, IL-33 was constitutively expressed in the nucleus of endothelial cells, immediately released in response to hepatic pedicle clamping without neosynthesis, and participated in the recruitment of neutrophils and tissue injury on site. The kinetics of IL-33 in liver transplant patients strikingly matched the ones in the animal model, as attested by serum levels reaching a peak immediately after reperfusion, which correlated to clinical outcomes including postreperfusion syndrome, posttransplant renal failure, graft dysfunction, and histological lesions of ischemia/reperfusion injury. IL-33 was an independent factor of graft dysfunction with a cutoff of IL-33 at 73 pg/ml after reperfusion (73% sensitivity, area under the curve of 0.76). Taken together, these findings establish the immediate implication of IL-33 acting as an alarmin in liver I/R injury and provide evidence of its close association with cardinal features of early liver injury-associated disorders in LT patients.

Technical characteristics and quality of grafts in liver procurement from brain-dead donors: A single-center study in Vietnamese population

Introduction

Donor liver graft quality plays an especially important role that contributes to the success of organ transplantation. Almost all local and international authors are interested in the techniques and results of transplantation, however, in Vietnam, there have not been any studies that report the results of liver procurement from brain-dead donors from a technical perspective as well as the morphology and function of the transplanted organ.

Materials and method

This study is descriptive cross-section study with analysis of retrospective occurrences of a series of cases of liver procurement from brain-dead donors from March 2010 to March 2020. All cases were proceeded the multiple organ procurement with warm liver dissection and in vivo cannulation and perfusion.

Results

The average age of brain-dead donors was 29.7 ± 10.7 (18–69), 92.16% of the harvested organs were of good quality macroscopically; and the rate of anatomical modification was 33.3% that occurred mostly in the left hepatic artery (LHA). Technically, warm dissection was proceeded in majority of cases (98,0%), the graft implantation was performed by this technique with mean cold ischemia time (CIT) of 190,0 ± 100,5 min and WIT of 74,0 ± 39,2 s. There were no complications relating to graft injuries occurring during procurement and no primary liver failure, good results accounted for 94.1% of the total number of transplants postoperatively.

Conclusion

Multiple organ procurement with warm liver dissection and in vivo cannulation and perfusion was a safe technique and may be effective by avoiding any donor's damages in cold-phase dissection.

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Liver transplantation in brain-dead donors had developed rapidly in recent decades.

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Several techniques were proceeded depend on experience and faculties of institute.

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In vivo perfusion and warm dissection can avoid graft's damages in cold dissection.

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Long-term follow-up is needed to evaluate quality of graft and overall survival.

The Influence of Donor and Recipient Complement C3 Polymorphisms on Liver Transplant Outcome

Despite early reports of an impact of complement C3 polymorphism on liver transplant patient and graft survival, subsequent evidence has been conflicting. Our aim was to clarify the contributions of donor and recipient C3 genotype, separately and together, on patient and graft outcomes and acute rejection incidence in liver transplant recipients. Eight donor/recipient groups were analyzed according to their genotype and presence or absence of C3 F allele (FFFS, FFSS, FSFF, FSFS, FSSS, SSFF, SSFS, and SSSS) and correlated with clinical outcomes of patient survival, graft survival, and rejection. The further impact of brain death vs. circulatory death during liver donation was also considered. Over a median 5.3 y follow-up of 506 patients with clinical information and matching donor and recipient tissue, five-year patient and graft survival (95% confidence interval) were 90(81-91)% and 77(73-85)%, respectively, and 72(69-94)% were rejection-free. Early disadvantages to patient survival were associated with donor C3 F variant, especially in brain-death donors. Recipient C3 genotype was an independent determinant of graft survival by Cox proportional hazards analysis (hazard ratio 0.26, P = 0.04), and the C3 F donor variant was again associated with worse liver graft survival, particularly in brain-death donors. C3 genotype did not independently determine rejection incidence, but a greater proportion of recipient C3 F carriers were rejection-free in the circulatory death, but not the brain-death cohort. Cox proportional hazards analysis revealed significant effects of acute rejection on patient survival (hazard ratio 0.24, P = 0.018), of retransplantation on rejection risk (hazard ratio 6.3, P = 0.009), and of donor type (circulatory-death vs. brain-death) on rejection incidence (hazard ratio 4.9, P = 0.005). We conclude that both donor and recipient complement C3 genotype may influence patient and graft outcomes after liver transplantation but that the type of liver donor is additionally influential, possibly via the inflammatory environment of the transplant.

RISK FACTORS ASSOCIATED WITH HEPATIC ARTERY THROMBOSIS: ANALYSIS OF 1050 LIVER TRANSPLANTS

Background:

Hepatic artery thrombosis is an important cause of graft loss and ischemic biliary complications. The risk factors have been related to technical aspects of arterial anastomosis and non-surgical ones.

Aim:

To evaluate the risk factors for the development of hepatic artery thrombosis.

Methods:

The sample consisted of 1050 cases of liver transplant. A retrospective and cross-sectional study was carried out, and the variables studied in both donor and recipient.

Results:

Univariate analysis indicated that the variables related to hepatic artery thrombosis are: MELD (p=0.04) and warm time ischemia (p=0.005). In the multivariate analysis MELD=14.5 and warm ischemia time =35 min were independent risk factors for hepatic artery thrombosis. In the prevalence ratio test for analysis of the anastomosis as a variable, it was observed that patients with continuous suture had an increase in thrombosis when compared to interrupted suture.

Conclusions:

Prolonged warm ischemia time, calculated MELD and recipient age were independent risk factors for hepatic artery thrombosis after liver transplantation in adults. Transplanted patients with continuous suture had an increase in thrombosis when compared to interrupted suture. Re-transplantation due to hepatic artery thrombosis was associated with higher recipient mortality.

Post-operative assessment in patients after liver transplantation: imaging parameters associated with 1-year graft failure

PURPOSE

To identify post-liver transplant CT findings which predict graft failure within 1 year.

MATERIALS AND METHODS

We evaluated the CT scans of 202 adult liver transplants performed in our institution who underwent CT within 3 months after transplantation. We recorded CT findings of liver perfusion defect (LPD), parenchymal homogeneity, and the diameters and attenuations of the hepatic vessels. Findings were correlated to 1-year graft failure, and interobserver variability was assessed.

RESULTS

Forty-one (20.3%) of the 202 liver grafts failed within 1 year. Graft failure was highly associated with LPD (n = 18/25, or 67%, versus 15/98, or 15%, p < 0.001), parenchymal hypoattenuation (n = 20/41, or 48.8% versus 17/161, or 10.6%, p < 0.001), and smaller diameter of portal veins (right portal vein [RPV], 10.7 ± 2.7 mm versus 14.7 ± 2.2 mm, and left portal vein [LPV], 9.8 ± 3.0 mm versus 12.4 ± 2.2 mm, p < 0.001, respectively). Of these findings, LPD (hazard ratio [HR], 5.43, p < 0.001) and small portal vein diameters (HR, RPV, 3.33, p < 0.001, and LPV, 3.13, p < 0.05) independently predicted graft failure. All the measurements showed fair to moderate interobserver agreement (0.233~0.597).

CONCLUSION

For patients who have CT scan within the first 3 months of liver transplantation, findings of LPD and small portal vein diameters predict 1-year graft failure.

KEY POINTS

•Failed grafts are highly associated with liver perfusion defect, hypoattenuation, and small portal vein. •Right portal vein < 11.5 mm and left portal vein < 10.0 mm were associated with poor graft outcome. •Liver perfusion defect and small portal vein diameter independently predicted graft failure.

Liver graft preservation methods during cold ischemia phase and normothermic machine perfusion

The growing demand for donor organs requires measures to expand donor pool. Those include extended criteria donors, such as elderly people, steatotic livers, donation after cardiac death, etc. Static cold storage to reduce metabolic requirements developed by Collins in late 1960s is the mainstay and the golden standard for donated organ protection. Hypothermic machine perfusion provides dynamic organ preservation at 4°C with protracted infusion of metabolic substrates to the graft during the ex vivo period. It has been used instead of static cold storage or after it as short perfusion in transplant center. Normothermic machine perfusion (NMP) delivers oxygen, and nutrition at physiological temperature mimicking regular environment in order to support cellular function. This would minimize effects of ischemia/reperfusion injury. Potentially, NMP may help to estimate graft functionality before implantation into a recipient. Clinical studies demonstrated at least its non-inferiority or better outcomes vs static cold storage. Regular grafts donated after brain death could be safely preserved with convenient static cold storage. Except for prolonged ischemia time where hypothermic machine perfusion started in transplant center could be estimated to provide possible positive reconditioning effect. Use of hypothermic machine perfusion in regular donation instead of static cold storage or in extended criteria donors requires further investigation. Multicenter randomized clinical trial supposed to be completed in December 2021. Extended criteria donors need additional measures for graft storage and assessment until its implantation. NMP is actively evaluating promising method for this purpose. Future studies are necessary for precise estimation and confirmation to issue clinical practice recommendations.

Recipient Selection for Optimal Utilization of Discarded Grafts in Liver Transplantation

BACKGROUND

In France, liver grafts that have been refused by at least 5 teams are considered for rescue allocation (RA), with the choice of the recipient being at the team's discretion. Although this system permits the use of otherwise discarded grafts in a context of organ shortage, outcomes and potential benefits need to be assessed.

METHODS

Between 2011 and 2015, outcomes of RA grafts (n = 33) were compared with SA grafts (n = 321) at a single French center.

RESULTS

Liver grafts in the RA group were older (63 ± 17 years vs 54 ± 18 years, P = 0.007) and had a higher DRI (1.86 ± 0.45 vs 1.61 ± 0.47, P = 0.010). Recipients in this group had a lower Model for End-Stage Liver Disease score (14 ± 5 vs 22 ± 10, P < 0.001) and had mostly hepatocellular carcinoma (67.0% vs 40.4%, P = 0.010). The balance of risk score was significantly lower in the RA group (5.5 ± 2.9 vs 9.2 ± 5.5, P < 0.001). There were higher rates of early and delayed hepatic artery thrombosis (15.2% vs 3.1%, P = 0.001) and retransplantation (18.2% vs 4.7%, P = 0.002) in the RA group. Patient survival was not different between groups, but graft survival was impaired (95% vs 82% at 1 year and 94% vs 74% at 3 years, P = 0.001).

CONCLUSION

Our results show that discarded liver grafts can be used provided that there is a strict recipient selection process, although hepatic artery thrombosis and retransplantation are more frequent. This strategy enables utilization of otherwise discarded grafts in the context of organ shortage.

The Role of Normothermic Perfusion in Liver Transplantation (TRaNsIT Study): A Systematic Review of Preliminary Studies

INTRODUCTION

The success of liver transplantation has been limited by the unavailability of suitable donor livers. The current organ preservation technique, i.e., static cold storage (SCS), is not suitable for marginal organs. Alternatively, normothermic machine perfusion (NMP) promises to recreate the physiological environment and hence holds promise for the better organ preservation. The objective of this systematic review is to provide an overview of the safety, benefits, and insight into the other potential useful parameters of NMP in the liver preservation.

MATERIAL AND METHODS

We searched the current literature following registration in the International Prospective Register of Systematic Reviews (PROSPERO) with registration number CRD42018086034 for prospective trials comparing the role of NMP device to SCS in liver transplant by searching the PubMed, EMBASE, Cochrane, BIOSIS, Crossref, and Scopus databases and clinical trial registry.

RESULTS

The literature search identified five prospective clinical trials (four being early phase single institutional and single randomized multi-institutional) comparing 187 donor livers on NMP device to 273 donor livers on SCS. The primary outcome of interest was to assess the safety and graft survival at day 30 after transplant following NMP of the donor liver. Secondary outcomes included were early allograft dysfunction (EAD) in the first seven days; serum measures of liver functions as bilirubin, aspartate aminotransferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), and international normalized ratio (INR) on days 1-7; major complications as defined by a Clavien-Dindo score ≥ 3; and patient and graft survival and biliary complications at six months. The peaked median AST level between days 1 and 7 in the five trials was 417-1252 U/L (range 84-15009 U/L) while on NMP and 839-1474 U/L (range 153-8786 U/L) in SCS group. The median bilirubin level on day 7 ranged within 25-79 µmol/L (range 8-344 µmol/l) and 30-47.53 µmol/l (range 9-340 µmol/l) in NMP and SCS groups, respectively. A single case of PNF was reported in NMP group in the randomized trial while none of the other preliminary studies reported any in either group. There was intertrial variability in EAD which ranged within 15-56% in NMP group while being within 23-37% in SCS group. Biliary complications observed in NMP group ranged from 0 to 20%. Single device malfunction was reported in randomized controlled trial leading to renouncement of transplant while none of the other trials reported any machine failure, although two user related device errors inadvertent were reported.

CONCLUSION

This review outlines that NMP not only demonstrated safety and efficacy but also provided the favourable environment of organ preservation, repair, and viability assessment to donor liver prior to the transplantation with low rate of posttransplantation complication as PNF, EAD, and biliary complication; however further studies are needed to broaden our horizon.

Glycome Patterns of Perfusate in Livers Before Transplantation Associate With Primary Nonfunction

BACKGROUND & AIMS

Primary nonfunction (PNF) is a rare complication after liver transplantation that requires urgent retransplantation. PNF is associated with livers from extended criteria donors. Clinical and biochemical factors have not been identified that reliably associate with graft function after liver transplantation. Serum patterns of N-glycans associate with changes in the liver. We analyzed perfusate from grafted liver to identify protein glycosylation patterns associated with PNF.

METHODS

We performed a prospective study of consecutive patients who underwent liver transplantation (66 patients, from 1 center, in the derivation set, and 56 patients, from 2 centers, in the validation set) in Belgium, from October 1, 2011, through April 30, 2017. All donor grafts were transported using cold static storage, and perfusate samples were collected from the livers by flushing of hepatic veins before transplantation. Protein-linked N-glycans were isolated from perfusate samples and analyzed with a multicapillary electrophoresis-based ABI3130 sequencer. We compared glycan patterns between patients with vs without PNF of transplanted livers. PNF was defined as the need for urgent retransplantation when a graft had no evidence of function, after exclusion of other causes, such as hepatic artery thrombosis or acute cellular rejection.

RESULTS

The relative abundance of a single glycan, agalacto core-alpha-1,6-fucosylated biantennary glycan (NGA2F) was significantly increased in perfusate of livers given to 4 patients who developed PNF after liver transplantation compared with livers given to patients who did not develop PNF. Level of NGA2F identified patients with PNF with 100% accuracy. This glycomarker was the only factor associated with PNF in multivariate analysis in the derivation and the validation sets (P < .0001).

CONCLUSIONS

In an analysis of patients who underwent liver transplantation, we associated graft perfusate level of glycan NGA2F present on perfusate proteins with development of PNF with 100% accuracy, and validated this finding in a separate cohort of patients. This biomarker might be used to assess grafts before transplantation, especially when high-risk organs are under consideration.

Actual Risk of Using Very Aged Donors for Unselected Liver Transplant Candidates: A European Single-center Experience in the MELD Era

OBJECTIVE

To evaluate the whole experience of liver transplantation (LT) with donors ≥70 years in a single center not applying specific donor/recipient matching criteria.

BACKGROUND

LT with very old donors has historically been associated with poorer outcomes. With the increasing average donor age and the advent of Model for End-stage Liver Diseases (MELD) score-based allocation criteria, an optimal donor/recipient matching is often unsuitable.

METHODS

Outcomes of all types of LTs were compared according to 4 study groups: patients transplanted between 1998 and 2003 with donors <70 (group 1, n = 396) or ≥70 years (group 2, n = 88); patients transplanted between 2004 and 2010 with donors <70 (group 3, n = 409), or ≥70 years (group 4, n = 190). From 2003, graft histology was routinely available before cross-clamping, and MELD-driven allocation was adopted.

RESULTS

Groups 1 and 2 were similar for main donor and recipient variables, and surgical details. Group 4 had shorter donor ICU stay, lower rate of moderate-to-severe graft macrosteatosis (2.3% vs 8%), and higher recipient MELD score (22 vs 19) versus group 3. After 2003, median donor age, recipient age, and MELD score significantly increased, whereas moderate-to-severe macrosteatosis and ischemia time decreased. Five-year graft survival was 63.6% in group 1 versus 59.1% in group 2 (P = 0.252) and 70.9% in group 3 versus 67.6% in group 4 (P = 0.129). Transplants performed between 1998 and 2003, recipient HCV infection, balance of risk score >18, and pre-LT renal replacement treatments were independently associated with worse graft survival.

CONCLUSIONS

Even without specific donor/recipient matching criteria, the outcomes of LT with donors ≥70 and <70 years are comparable with appropriate donor management.

The postoperative Model for End stage Liver Disease score as a predictor of short-term outcome after transplantation of extended criteria donor livers

BACKGROUND

Recently, the postoperative Model for End stage Liver Disease score (POPMELD) was suggested as a definition of postoperative graft dysfunction and a predictor of outcome after liver transplantation (LT).

AIM

The aim of the present study was to validate this concept in the context of extended criteria donor (ECD) organs.

PATIENTS AND METHODS

Single-center prospectively collected data (OPAL study/01/11-12/13) of 116 ECD LTs were utilized. For each recipient, the Model for End stage Liver Disease (MELD) score was calculated for 7 postoperative days (PODs). The ability of international normalized ratio, bilirubin, aspartate aminotransferase, Donor Risk Index, a recent definition of early allograft dysfunction, and the POPMELD was compared to predict 90-day graft loss. Predictive abilities were compared by receiver operating characteristic curves, sensitivity and specificity, and positive and negative predictive values.

RESULTS

The median Donor Risk Index was 1.8. In all, 60.3% of recipients were men [median age of 54 (23-68) years]. The median POD1-7 peak-aspartate aminotransferase value was 1052 (194-17 577) U/l. The rate of early allograft dysfunction was 22.4%. The 90-day graft survival was 89.7%. Out of possible predictors of the 90-day graft loss MELD on POD5 was the best predictor of outcome (area under the curve=0.84). A MELD score of 16 or more on POD5 predicted the 90-day graft loss with a specificity of 80.8%, a sensitivity of 81.8%, and a positive and negative predictive value of 31 and 97.7%.

CONCLUSION

A MELD score of 16 or more on POD5 is an excellent predictor of outcome in ECD donor LT. Routine evaluation of POPMELD scores might support clinical decision-making and should be reported routinely in clinical trials.

Neurologic complications of transplantation

Major neurologic morbidity, such as seizures and encephalopathy, complicates 20-30% of organ and stem cell transplantation procedures. The majority of these disorders occur in the early posttransplant period, but recipients remain at risk for opportunistic infections and other nervous system disorders for many years. These long-term risks may be increasing as acute survival increases, and a greater number of "sicker" patients are exposed to long-term immunosuppression. Drug neurotoxicity accounts for a significant proportion of complications, with posterior reversible leukoencephalopathy syndrome, primarily associated with calcineurin inhibitors (i.e., cyclosporine and tacrolimus), being prominent as a cause of seizures and neurologic deficits. A thorough evaluation of any patient who develops neurologic symptoms after transplantation is mandatory, since reversible and treatable conditions could be found, and important prognostic information can be obtained.

Autoimmune conditions are associated with perioperative thrombotic complications in liver transplant recipients: A UNOS database analysis

BACKGROUND

End stage liver disease (ESLD) is associated with significant thrombotic complications. In this study, we attempted to determine if patients with ESLD, due to oncologic or autoimmune diseases, are susceptible to thrombosis to a greater extent than patients with ESLD due to other causes.

METHODS

In this retrospective study, we analyzed the UNOS database to determine the incidence of thrombotic complications in orthotopic liver transplant (OLT) recipients with autoimmune and oncologic conditions. Between 2000 and 2012, 65,646 OLTs were performed. We found 4,247 cases of preoperative portal vein thrombosis (PVT) and 1,233 cases of postoperative vascular thrombosis (VT) leading to graft failure.

RESULTS

Statistical evaluation demonstrated that patients with either hepatocellular carcinoma (HCC) or autoimmune hepatitis (AIC) had a higher incidence of PVT (p = 0.05 and 0.03 respectively). Patients with primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and AIC had a higher incidence of postoperative VT associated with graft failure (p < 0.0001, p < 0.0001, p = 0.05 respectively). Patients with preoperative PVT had a higher incidence of postoperative VT (p < 0.0001). Multivariable logistic regression demonstrated that patients with AIC, and BMI ≥40, having had a transjugular intrahepatic portosystemic shunt, and those with diabetes mellitus were more likely to have preoperative PVT: odds ratio (OR)(1.36, 1.19, 1.78, 1.22 respectively). Patients with PSC, PBC, AIC, BMI ≤18, or with a preoperative PVT were more likely to have a postoperative VT: OR (1.93, 2.09, 1.64, 1.60, and 2.01, respectively).

CONCLUSION

Despite the limited number of variables available in the UNOS database potentially related to thrombotic complications, this analysis demonstrates a clear association between autoimmune causes of ESLD and perioperative thrombotic complications. Perioperative management of patients at risk should include strategies to reduce the potential for these complications.

Overexpression of the long noncoding RNA TUG1 protects against cold-induced injury of mouse livers by inhibiting apoptosis and inflammation

Hepatic injury provoked by cold storage is a major problem affecting liver transplantation, as exposure to cold induces apoptosis in hepatic tissues. Long noncoding RNAs (lncRNAs) are increasingly understood to regulate apoptosis, but the contribution of lncRNAs to cold-induced liver injury remains unknown. Using RNA-seq, we determined the differential lncRNA expression profile in mouse livers after cold storage and found that expression of the lncRNA TUG1 was significantly down-regulated. Overexpression of TUG1 attenuated cold-induced apoptosis in mouse hepatocytes and liver sinusoidal endothelial cells LSECs, in part by blocking mitochondrial apoptosis and endoplasmic reticulum (ER) stress pathways. Moreover, TUG1 attenuated apoptosis, inflammation, and oxidative stress in vivo in livers subjected to cold storage. Overexpression of TUG1 also improved hepatocyte function and prolonged hepatic graft survival rates in mice. These results suggest that the lncRNA TUG1 exerts a protective effect against cold-induced liver damage by inhibiting apoptosis in mice, and suggests a potential role for TUG1 as a target for the prevention of cold-induced liver damage in liver transplantation.

DATABASES

RNA-seq data are available from GEO using accession number GSE76609.

Clinical outcomes and genetic expression profile in human liver graft dysfunction during ischemia/reperfusion injury

INTRODUCTION

This study aims to compare the molecular gene expression during ischemia reperfusion injury. Several surgical times were considered: in the beginning of the harvesting (T0), at the end of the cold ischemia period (T1), and after reperfusion (T2) and compared with graft dysfunction after liver transplant (OLT).

METHODS

We studied 54 patients undergoing OLT. Clinical, laboratory data, and histologic data (Suzuki classification) as well as the Survival Outcomes Following Liver Transplantation (SOFT) score were used and compared with the molecular gene expression of the following genes: Interleukin (IL)-1b, IL-6, tumor necrosis factor-α, perforin, E-selectin (SELE), Fas-ligand, granzyme B, heme oxygenase-1, and nitric oxide synthetase.

RESULTS

Fifteen patients presented with graft dysfunction according to SOFT criteria. No relevant data were obtained by comparing the variables graft dysfunction and histologic variables. We observed a statistically significant relation between SELE at T0 (P = .013) and IL-1β at T0 (P = .028) and early graft dysfunction.

CONCLUSIONS

We conclude that several genetically determined proinflammatory expressions may play a critical role in the development of graft dysfunction after OLT.

Interferon-γ, interleukin-10 and interferon-inducible protein 10 (CXCL10) as serum biomarkers for the early allograft dysfunction after liver transplantation

Orthotopic liver transplantation (LTP) is nowadays a standard procedure, and provides the chance of survival of patients with end-stage non-treatable chronic liver disease or acute liver failure. Despite long-term survival with a good quality of life in the majority of patients, about 20% develop early allograft dysfunction (EAD), which leads to death or the need for re-transplantation. Therefore, the early diagnosis of EAD and evaluation of its risk factors are very important. Many primary pathological processes leading to EAD are accompanied by the release of different mediators and by a change of biochemical parameters detectable in the peripheral blood. The aim of this study was to investigate cytokines as well as soluble mediators in the serum of patients with and without EAD from our LTP bank, and to evaluate their predictive and prognostic values for EAD. We demonstrated for the first time that the level of IFNγ during the nearest preoperative period may serve as a predictive parameter for EAD. We additionally found that IL-10 and CXCL10 (IP-10) levels in the early postoperative period can be prognostic for EAD. We believe our data expand the spectrum of predictive and prognostic parameters for EAD in LTP.

Effects of ischemic preconditioning in a pig model of large-for-size liver transplantation

OBJECTIVE

In most cases of pediatric liver transplantation, the clinical scenario of large-for-size transplants can lead to hepatic dysfunction and a decreased blood supply to the liver graft. The objective of the present experimental investigation was to evaluate the effects of ischemic preconditioning on this clinical entity.

METHODS

Eighteen pigs were divided into three groups and underwent liver transplantation: a control group, in which the weights of the donors were similar to those of the recipients, a large-for-size group, and a large-for-size + ischemic preconditioning group. Blood samples were collected from the recipients to evaluate the pH and the sodium, potassium, aspartate aminotransferase and alanine aminotransferase levels. In addition, hepatic tissue was sampled from the recipients for histological evaluation, immunohistochemical analyses to detect hepatocyte apoptosis and proliferation and molecular analyses to evaluate the gene expression of Bax (pro-apoptotic), Bcl-XL (anti-apoptotic), c-Fos and c-Jun (immediate-early genes), ischemia-reperfusion-related inflammatory cytokines (IL-1, TNF-alpha and IL-6, which is also a stimulator of hepatocyte regeneration), intracellular adhesion molecule, endothelial nitric oxide synthase (a mediator of the protective effect of ischemic preconditioning) and TGF-beta (a pro-fibrogenic cytokine).

RESULTS

All animals developed acidosis. At 1 hour and 3 hours after reperfusion, the animals in the large-for-size and large-for-size + ischemic preconditioning groups had decreased serum levels of Na and increased serum levels of K and aspartate aminotransferase compared with the control group. The molecular analysis revealed higher expression of the Bax, TNF-alpha, I-CAM and TGF-beta genes in the large-for-size group compared with the control and large-for-size + ischemic preconditioning groups. Ischemic preconditioning was responsible for an increase in c-Fos, IL-1, IL-6 and e-NOS gene expression.

CONCLUSION

Ischemia-reperfusion injury in this model of large-for-size liver transplantation could be partially attenuated by ischemic preconditioning.

Complications following hepatectomy

As the number of liver resections in the United States has increased, operations are more commonly performed on older patients with multiple comorbidities. The advent of effective chemotherapy and techniques such as portal vein embolization, have compounded the number of increasingly complex resections taking up to 75% of healthy livers. Four potentially devastating complications of liver resection include postoperative hemorrhage, venous thromboembolism, bile leak, and post-hepatectomy liver failure. The risk factors and management of these complications are herein explored, stressing the importance of identifying preoperative factors that can decrease the risk for these potentially fatal complications.

Effect of mannitol on postreperfusion cardiac output and central venous oxygen saturation during orthotopic liver transplant: a double-blind randomized clinical trial

CONTEXT

Attenuating postreperfusion syndrome during orthotopic liver transplant is very important for transplant anesthesiologists because of the syndrome's complications. Oxygen-derived free radicals play an important role in the genesis of postreperfusion syndrome, but the effect of mannitol (a free radical scavenger) on attenuating the syndrome is unclear.OBJECTIVES-To investigate the effectiveness of infusing mannitol during the anhepatic phase in preventing postreperfusion syndrome, as indicated by postreperfusion cardiac output and central venous oxygen saturation.

DESIGN

In a randomized clinical trial, 53 patients who had undergone orthotopic liver transplant were allocated to 2 groups. During the anhepatic phase, patients in the mannitol group received 1g/kg mannitol, whereas those in the control group received physiological saline. Mean arterial pressure, cardiac output, and central venous oxygen saturation were measured before and after the portal vein was declamped. Serum levels of sodium and potassium were recorded at baseline and after portal vein declamping.Setting-Shiraz Organ Transplant Center, Shiraz, Iran.

RESULTS

In the mannitol group, no significant change was found in mean arterial pressure, cardiac output, and central venous oxygen saturation before and after declamping of the portal vein (P= .78, P= .59, and P= .83, respectively). However, after declamping in the control group, mean arterial pressure, cardiac output, and central venous oxygen saturation were significantly lower than before declamping (P=.003, P=.001, and P<.001, respectively). No significant change in serum levels of sodium and potassium from baseline to after declamping were found in either group.

CONCLUSION

Infusion of mannitol 1 g/kg during the anhepatic phase was effective in attenuating postreperfusion syndrome without stress about hyperkalemia or hyponatremia during anesthesia.

Biomarkers to assess graft quality during conventional and machine preservation in liver transplantation

A global rising organ shortage necessitates the use of extended criteria donors (ECD) for liver transplantation (LT). However, poor preservation and extensive ischemic injury of ECD grafts have been recognized as important factors associated with primary non-function, early allograft dysfunction, and biliary complications after LT. In order to prevent for these ischemia-related complications, machine perfusion (MP) has gained interest as a technique to optimize preservation of grafts and to provide the opportunity to assess graft quality by screening for extensive ischemic injury. For this purpose, however, objective surrogate biomarkers are required which can be easily determined at time of graft preservation and the various techniques of MP. This review provides an overview and evaluation of biomarkers that have been investigated for the assessment of graft quality and viability testing during different types of MP. Moreover, studies regarding conventional graft preservation by static cold storage (SCS) were screened to identify biomarkers that correlated with either allograft dysfunction or biliary complications after LT and which could potentially be applied as predictive markers during MP. The pros and cons of the different biomaterials that are available for biomarker research during graft preservation are discussed, accompanied with suggestions for future research. Though many studies are currently still in the experimental setting or of low evidence level due to small cohort sizes, the biomarkers presented in this review provide a useful handle to monitor recovery of ECD grafts during clinical MP in the near future.

Quantifying tissue mechanical properties using photoplethysmography

Photoplethysmography (PPG) is a non-invasive optical method that can be used to detect blood volume changes in the microvascular bed of tissue. The PPG signal comprises two components; a pulsatile waveform (AC) attributed to changes in the interrogated blood volume with each heartbeat, and a slowly varying baseline (DC) combining low frequency fluctuations mainly due to respiration and sympathetic nervous system activity. In this report, we investigate the AC pulsatile waveform of the PPG pulse for ultimate use in extracting information regarding the biomechanical properties of tissue and vasculature. By analyzing the rise time of the pulse in the diastole period, we show that PPG is capable of measuring changes in the Young's Modulus of tissue mimicking phantoms with a resolution of 4 KPa in the range of 12 to 61 KPa. In addition, the shape of the pulse can potentially be used to diagnose vascular complications by differentiating upstream from downstream complications. A Windkessel model was used to model changes in the biomechanical properties of the circulation and to test the proposed concept. The modeling data confirmed the response seen in vitro and showed the same trends in the PPG rise and fall times with changes in compliance and vascular resistance.

Comparison of short- and long-term outcomes after early versus late liver retransplantation: a single-center experience

BACKGROUND

As the survival of patients after liver transplantation (LT) improves, the requirement of liver retransplantation (reLT) for late graft failure has grown. Although some have reported that the short-term outcome of late reLT was comparable with that of early reLT, it remains unknown whether long-term survival of late reLT is inferior to that of early reLT patients.

MATERIALS AND METHODS

We reviewed early (<6 mo after primary LT) and late (≥6 mo after primary LT) reLT cases performed between January 2000 and December 2010.

RESULTS

Sixteen early and 32 late reLT cases were analyzed. There was no significant difference regarding the number of units of red blood cells transfused during the transplantation between the groups, whereas operative time was significantly longer in the late reLT cases. Graft loss within 3 mo after early and late reLT was 18.6% and 15.6%, respectively. Patient and graft survival rates after 1, 3, 5, and 10 y in the late reLT group were 80.6%, 73.3%, 73.3%, and 67.7% and 80.7%, 69.1%, 63.3%, and 54.3%, respectively, whereas those in the early reLT group were 75.0%, 75.0%, 64.3%, and 64.3% and 81.3%, 75.0%, 64.3%, and 32.1%, respectively. There was no significant difference in patient or graft survival rates between the groups (P = 0.91 and 0.91, respectively).

CONCLUSIONS

Acceptable short- and long-term survival were provided in early and late reLT. The time between the primary LT and reLT does not seem to play significant role in the prognosis of reLT in the long term.

Predicting early allograft failure and mortality after liver transplantation: the role of the postoperative model for end-stage liver disease score

Early allograft dysfunction (EAD) is a serious complication after liver transplantation (LT). There is no uniform definition of EAD, and most definitions are based on arbitrary laboratory values. The aim of this study was to devise a definition of EAD that maximizes the predictive power for early death and graft failure. In this single-center, retrospective study, the ability of the international normalized ratio (INR), total bilirubin, aspartate aminotransferase (AST), physiological Model for End-Stage Liver Disease (MELD) score, and serum albumin levels within 7 days after LT to predict 90-day mortality or graft loss was compared with 2 previously used definitions of EAD: (1) peak total bilirubin level >10 mg/dL on days 2 to 7 and (2) either a total bilirubin level >10 mg/dL or an INR >1.6 on day 7 or an AST or alanine aminotransferase level >2000 IU/L within the first 7 days. Of 572 enrolled LT patients 38 died or required retransplantation within 90 days. Peak INR, total bilirubin level, AST levels, and MELD scores were predictors of 90-day graft failure. MELD score on postoperative day 5 was the best predictor with an area under the curve of the receiver operating characteristic curve of 0.812 (95% CI: 0.739-0.886, P < 0.001). The best cutoff of MELD score on day 5 for predicting 90-day mortality or graft loss was 18.9. A MELD score >18.9 on postoperative day 5 was a better predictor than any other laboratory value or definition of EAD. This study has demonstrated that the MELD score can be a useful tool not only for pretransplant graft allocation but also for postoperative risk stratification.

The immunomodulatory role of carbon monoxide during transplantation

The number of organ and tissue transplants has increased worldwide in recent decades. However, graft rejection, infections due to the use of immunosuppressive drugs and a shortage of graft donors remain major concerns. Carbon monoxide (CO) had long been regarded solely as a poisonous gas. Ultimately, physiological studies unveiled the endogenous production of CO, particularly by the heme oxygenase (HO)-1 enzyme, recognizing CO as a beneficial gas when used at therapeutic doses. The protective properties of CO led researchers to develop uses for it, resulting in devices and molecules that can deliver CO in vitro and in vivo. The resulting interest in clinical investigations was immediate. Studies regarding the CO/HO-1 modulation of immune responses and their effects on various immune disorders gave rise to transplantation research, where CO was shown to be essential in the protection against organ rejection in animal models. This review provides a perspective of how CO modulates the immune system to improve transplantation and suggests its use as a therapy in the field.

Have we changed the liver retransplantation survival?

INTRODUCTION

Orthotropic liver retransplantation (RT) is the therapeutic option for the failure of an allograft. Patient and graft survival rates after RT are inferior to primary liver transplantation (OLT). Because of the limited number of donors, it is essential that we optimize their use. We reviewed 68 consecutive retransplantations to evaluate their results.

MATERIALS AND METHODS

Using registry data from our Liver Transplantation Unit, we performed a retrospective cohort study of adult RT between 1991 and 2010. Patients were divided into 2 groups (urgent vs elective RT) to compare the utility of RT. We also analyzed data collected at the time of RT, including age, gender, indications for primary OLT and RT (hepatitis C virus [HCV]+ and HCV-). At various stages (1991-2000, 2001-2006, and 2007-2010), we calculated probability survival curves according to the Kaplan-Meier method with comparisons using the log-rank test.

RESULTS

Among 771 adult liver transplantations, 68 (8.8%) underwent late secondary OLT. 21 (31%) cases were urgent and 47 elective RT (69%). Vascular complications was the most common cause for urgent RT, and chronic rejection, for elective RT. Differences were also detected in the overall survival of RT patients; mortality was significantly lower among the urgent procedures (15% vs 47.8%). Significantly differences were also detected in overall survival for RT patients between 2007 and 2010 (81.7% with urgent RT and 76.5% with elective situations).

CONCLUSION

These data confirmed the utility of RT in elective and emergency situations. Overall survival of elective RT patients has improved in recent years. Liver RT requires a multidisciplinary team to decide the inclusion and prioritization of elective RT cases on the OLT waiting list.

Long-term management of the liver transplant recipient: pearls for the practicing gastroenterologist

Liver transplantation is becoming more common and patients are surviving longer after transplantation. Special care must be paid to the long-term management of these patients because they are at increased risk for medical problems, malignancies, and adverse effects from immunosuppression. A stable and continuing relationship must be developed between the physician and the patient to optimize the long-term outcomes for these individuals.

Pharmacological postconditioning protects against hepatic ischemia/reperfusion injury

Postconditioning is a procedure based on the induction of intracellular protective reactions immediately after the onset of reperfusion. Because of the growing need to prevent ischemia/reperfusion (I/R) injury during liver surgery and transplantation, we investigated the possibility of pharmacologically inducing hepatic postconditioning. The effects of the adenosine A2A receptor agonist 2p-(2-carboxyethyl)-phenyl-amino-5'-N-ethylcarboxyamido-adenosine (CGS21680; 5 μmol/L) and the phosphatase and tensin homologue deleted from chromosome 10 (PTEN) inhibitor dipotassium bisperoxo-(5-hydroxypyridine-2-carboxyl)-oxovanadate [bpV(HOpic); 250 nmol/L] were investigated in primary rat hepatocytes during reoxygenation after 24 hours of cold storage and in an in vivo model of rat liver warm I/R. The addition of CGS21680 at reoxygenation significantly reduced hepatocyte death through the activation of the phosphoinositide 3-kinase (PI3K)-protein kinase B (PKB)/Akt signal pathway and through the reduction of the intracellular level of PTEN. PTEN lowering was associated with the increased generation of reactive oxygen species after A2A receptor-mediated stimulation of β-nicotinamide adenine dinucleotide phosphate oxidase (NOX). The inhibition of PI3K or NOX with wortmannin or diphenyleneiodonium chloride, respectively, and the addition of the antioxidant N,N'-diphenyl-p-phenylenediamine reversed the effects of CGS21680. The PTEN inhibitor bpV(HOpic) mimicked the protection provided by CGS21680 against reoxygenation damage. An in vivo rat treatment with CGS21680 or bpV(HOpic) during reperfusion after 1 hour of partial hepatic ischemia also promoted PKB/Akt activation and ameliorated alanine aminotransferase release and histological lesions induced by 2 hours of reperfusion. We conclude that adenosine A2A receptor agonists and PTEN inhibitors are possibly useful agents for the pharmacological induction of postconditioning in the liver.

Risk factors associated with early hepatic artery thrombosis after orthotopic liver transplantation - univariable and multivariable analysis

Hepatic artery thrombosis (HAT) is a serious complication in patients undergoing orthotopic liver transplantation (OLT). It is associated with a high graft loss and mortality rate. In this study, possible risk factors associated with early HAT (occurring within the first postoperative month) were evaluated using univariable and multivariable analyses. Nine-hundred-and-fourteen consecutive OLTs in our institution were examined by univariable and multivariable analyses. Early HAT occurred in 43 patients (4.7%). Graft number, abnormal donor arterial anatomy, bench arterial reconstruction, aortic conduit use, multiple anastomoses, reperfusion time (interval between portal vein reperfusion and restoration of arterial flow) and the number of units of blood received intraoperatively were significantly associated with early HAT in the univariable analysis(P<0.1). These variables were included in a multivariable regression model which showed that bench arterial reconstruction was associated with a fourfold risk of early HAT(P<0.0001), whereas each additional 10min delay in reperfusion was associated with a 27% increase in the risk of early HAT (P<0.04). The main risk factors associated with early HAT are abnormal arterial anatomy in the graft requiring bench reconstruction and a delay in arterial reperfusion. Early recognition of these factors, strict surveillance protocols with arterial Doppler and selective anticoagulation for patients at risk need to be evaluated prospectively.

Indications for and survival after liver retransplantation

INTRODUCTION

Orthotopic liver retransplantation (re-OLT) is the therapeutic option for hepatic graft failures. Survival after re-OLT is poorer than after primary OLT. Given that there is an organ shortage, it is essential that we optimize our use of this scarce resource. We evaluated the results of re-OLT among 58 consecutive Re-OLT.

MATERIALS AND METHODS

Using registry data from our Liver Transplantation Unit, we performed a retrospective cohort study of adult urgent versus elective re-OLT between 1991 and 2008. We recorded the indications for the initial OLT, and the intervals from OLT to re-OLT as well as age and gender. Using the Rosen model to stratify patients into low-intermediate-, and high-risk groups we calculated survivals.

RESULTS

Among 661 adult liver transplantations, 56 patients (8.4%) underwent late re-OLT at a median of 654.4 days post-OLT. There were 17 (29%) urgent re-OLT and 41 elective cases (71%). Vascular complications were the most common cause of urgent re-OLT (64%); elective re-OLT was primarily due to chronic rejection (56.1%). Overall survival for retransplanted patients was significantly lower among urgent procedures (82.4% vs 48.8%), as well as for overall survival after re-OLT for patients with hepatitis C virus (HCV) versus other etiologies.

CONCLUSION

These data confirmed the utility of retransplantation in elective and emergency situations. Liver re-transplantation has a high morbidity and mortality. It requires multidisciplinary experience to decide inclusion and prioritization criteria for re-OLT, especially among patients with HCV.

TLR2 and TLR4 in ischemia reperfusion injury

Ischemia reperfusion (I/R) injury refers to the tissue damage which occurs when blood supply returns to tissue after a period of ischemia and is associated with trauma, stroke, myocardial infarction, and solid organ transplantation. Although the cause of this injury is multifactorial, increasing experimental evidence suggests an important role for the innate immune system in initiating the inflammatory cascade leading to detrimental/deleterious changes. The Toll-like Receptors (TLRs) play a central role in innate immunity recognising both pathogen- and damage-associated molecular patterns and have been implicated in a range of inflammatory and autoimmune diseases. In this paper, we summarise the current state of knowledge linking TLR2 and TLR4 to I/R injury, including recent studies which demonstrate that therapeutic inhibition of TLR2 has beneficial effects on I/R injury in a murine model of myocardial infarction.

Adrenomedullin in sinusoidal endothelial cells play protective roles against cold injury of liver

Donor organ damage caused by cold preservation is a major problem affecting liver transplantation. Cold preservation most easily damages liver sinusoidal endothelial cells (LSECs), and information about the molecules modulating LSECs function can provide the basis for new therapeutic strategies. Adrenomedullin (AM) is a peptide known to possess anti-apoptotic and anti-inflammatory properties. AM is abundant in vascular endothelial cells, but levels are comparatively low in liver, and little is known about its function there. In this study, we demonstrated both AM and its receptors are expressed in LSECs. AM treatment reduced LSECs loss and apoptosis under cold treatment. AM also downregulated cold-induced expression of TNFalpha, IL1beta, IL6, ICAM1 and VCAM1. AM reduced apoptosis and expression of ICAM1 and VCAM1 in an in vivo liver model subjected to cold storage. Conversely, apoptosis was exacerbated in livers from AM and RAMP2 (AM receptor activity-modifying protein) knockout mice. These results suggest that AM expressed in LSECs exerts a protective effect against cold-organ damage through modulation of apoptosis and inflammation.

Survival benefit after liver transplantation: a single European center experience

BACKGROUND

The evaluation of the survival achieved with liver transplantation (LT) compared with remaining on the waiting list, the transplant benefit, should be the underlying principle of organ allocation.

METHODS

During 2004 to 2007 with an allocation system based on Model for End-Stage Liver Disease (MELD) score with exceptions, we prospectively evaluated the transplant benefit and its relation to the match between recipient and donor characteristics.

RESULTS

Among 575 patients listed for chronic liver disease, 218 (37.9%) underwent LT and 115 (20%) were removed from the list (76 deaths, 25 tumor progressions, and 14 sick conditions). The 1- and 3-year survival rates on the list were significantly related to MELD score more than or equal to 20 (57% and 33% vs. 88% and 66%, P<0.001) and to its progression during the waiting time, such as s-Na levels less than or equal to 135 mEq/L (73% and 48% vs. 86% and 69%, P<0.001). These two variables had no impact on survival after LT, except in hepatitis C virus positive recipients. The multivariate Cox model confirmed a positive transplant benefit for all cases with MELD score more than or equal to 20 and without hepatocellular carcinoma (HR 2.9; CI 1.3-6.2) independently of the type of donors. Only hepatocellular carcinoma patients with low MELD scores showed a positive transplant benefit (MELD <15; HR 2; CI 1.1-5.1).

CONCLUSIONS

LT should be reserved for cirrhotic patients with MELD score more than or equal to 20 independently of other recipient and donor matches or for cases with lower MELD score but with hepatocellular carcinoma.

Increased risk of graft loss from hepatic artery thrombosis after liver transplantation with older donors

Hepatic artery thrombosis (HAT) is the most common vascular complication after liver transplantation; it has been reported to occur in 2% to 5% of liver transplant recipients. Most reports of HAT in the literature describe single-center series with small numbers of patients and lack the power to definitively identify nontechnical risk factors. We used the United Network for Organ Sharing database of adult deceased donor liver transplants from 1987 to 2006 to identify 1246 patients with graft loss from HAT. Univariate and multivariate regression analyses were performed to identify donor and graft risk factors for HAT-induced graft loss. Although most donor predictors of HAT-induced graft loss were surrogates for vessel size, donor age > 50 years was also a significant predictor of graft loss from HAT (relative risk = 1.45, P < 0.001). Furthermore, the risk of graft loss from HAT increased progressively with each decade of donor age > 50 years, such that a 61% increased risk of HAT-related graft loss (relative risk = 1.61, P < 0.001) was associated with donor age > 70 years. A separate analysis of risk factors for early HAT graft loss (<or=90 days) and late HAT graft loss (> 90 days) found that older donor age was associated with increased late HAT graft loss. These findings are of interest in an era of ongoing organ shortages requiring maximum utilization of potential allografts and increasing allocation of older allografts.

Preconditioning, organ preservation, and postconditioning to prevent ischemia-reperfusion injury to the liver

Ischemia and reperfusion lead to injury of the liver. Ischemia-reperfusion injury is inevitable in liver transplantation and trauma and, to a great extent, in liver resection. This article gives an overview of the mechanisms involved in this type of injury and summarizes protective and treatment strategies in clinical use today. Intervention is possible at different time points: during harvesting, during the period of preservation, and during implantation. Liver preconditioning and postconditioning can be applied in the transplant setting and for liver resection. Graft optimization is merely possible in the period between the harvest and the implantation. Given that there are 3 stages in which a surgeon can intervene against ischemia-reperfusion injury, we have structured the review as follows. The first section reviews the approaches using surgical interventions, such as ischemic preconditioning, as well as pharmacological applications. In the second section, static organ preservation and machine perfusion are addressed. Finally, the possibility of treating the recipient or postconditioning is discussed.

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.

Early hepatic artery thrombosis after liver transplantation: a systematic review of the incidence, outcome and risk factors

To clarify inconsistencies in the literature we performed a systematic review to identify the incidence, risk factors and outcome of early hepatic artery thrombosis (eHAT) after liver transplantation. We searched studies identified from databases (MEDLINE, EMBASE, Science Citation Index) and references of identified studies. Seventy-one studies out of 999 screened abstracts were eligible for this systematic review. The incidence of eHAT was 4.4% (843/21, 822); in children 8.3% and 2.9% in adults (p < 0.001). Doppler ultrasound screening (DUS) protocols varied from 'no routine' to 'three times a day.' The median time to detection was at day seven. The overall retransplantation rate was 53.1% and was higher in children (61.9%) than in adults (50%, p < 0.03). The overall mortality rate of patients with eHAT was 33.3% (range: 0-80%). Mortality in adults (34.3%) was higher than in children (25%, p < 0.03). The reported risk factors for eHAT were, cytomegalovirus mismatch (seropositive donor liver in seronegative recipient), retransplantation, arterial conduits, prolonged operation time, low recipient weight, variant arterial anatomy, and low volume transplantation centers. eHAT is associated with significant graft loss and mortality. Uniform definitions of eHAT and uniform treatment modalities are obligatory to confirm these results and to obtain a better understanding of this disastrous complication.

[Liver transplantation: influence of donor-related factors]

OBJECTIVE

To detect donor characteristics related to graft function after orthotopic liver transplantation (OLT).

DESIGN

Retrospective cohort study.

CONTEXT

Polyvalent intensive care unit.

PATIENTS

145 liver transplant recipients and their respective donors.

INTERVENTIONS

None.

MAIN VARIABLES OF INTEREST

In donors: age, hypernatremia, and infection. In recipients: reperfusion syndrome, coagulopathy, infection, ARDS, shock, kidney failure, primary graft dysfunction, and mortality.

RESULTS

71.7% of recipients were male. Mean recipient age was 54.5 +/- 9.9 years; 66.2% of patients were classified as Child B and and 19.3% as Child C. The mean model for end-stage liver disease (MELD) score was 14.6 +/- 4.8 and the mean APACHE II score was 17.3 +/- 4.9. A total of 64.1% of the donors were male. Mean donor age was 42.3 +/- 16.3 years, and mean APACHE II score was 22.3 +/- 5.8. Donor age > 65 years was associated to higher recipient aspartate aminotransferase (AST) levels but not to increased complications or mortality. No other donor factors (including age, sex, serum sodium, severity level, transfusions, hemodynamic alterations, renal dysfunction, or infection) were associated to evolution or prognosis. Infection was diagnosed in 18 recipients (12.4%) in the postoperative period; the incidence of infection in recipients that received an organ from infected donors was not different from those that received an organ from an uninfected donor (14.6% versus 11.5%; p > 0.05).

CONCLUSIONS

We detected no donor characteristics related to graft function or the appearance of complications in recipients during the immediate postoperative period. Donor age > 65 years and documented but appropriately treated bacteremia posed no risk for the viability of the liver after transplantation.

Liver transplantations with donors aged 60 years and above: the low liver damage strategy

According to transplant registries, grafts from elderly donors have lower survival rates. During 1999-2005, we evaluated the outcomes of 89 patients who received a liver from a donor aged > or = 60 years and managed with the low liver-damage strategy (LLDS), based on the preoperative donor liver biopsy and the shortest possible ischemia time (group D > or = 60-LLDS). Group D > or = 60-LLDS was compared with 198 matched recipients, whose grafts were not managed with this strategy (89 donors < 60 years, group D < 60-no-LLDS and 89 donors aged > or =60 years, group D > or = 60-no-LLDS). In the donors proposed from the age group of > or =60 years, the number of donors rejected decreased during the study period and the LLDS was found to be responsible for this in a significant manner (47% vs. 60%, respectively P < 0.01). Among the recipients transplanted, the clinical features (age, gender, viral infection, child and model for end-stage liver disease score) were comparable among groups, but group D > or = 60-LLDS had a lower mean ischemia time: 415 +/- 106 min vs. 465 +/- 111 (D < 60-no-LLDS), P < 0.05 and vs. 476 +/- 94 (D > or = 60-no-LLDS), P < 0.05. After a median follow-up of 3 years, the 1- and 3-year graft survival rates of group D > or = 60-LLDS (84% and 76%) were comparable with group D < 60-no-LLDS (89% and 76%) and were significantly higher than group D > or = 60-no-LLDS (71% and 54%), P < 0.005. In conclusion, the LLDS optimized the use of livers from elderly donors.

Improving the outcome of liver transplantation with very old donors with updated selection and management criteria

Advanced donor age is a risk factor for poor outcome in liver transplantation (LT). We reviewed 553 consecutive transplants according to donor age categories [group 1 (n = 173): <50 years; group 2 (n = 96): 50-59 years; group 3 (n = 132): 60-69 years; group 4 (n = 111): 70-79 years; group 5 (n = 41): > or =80 years]. Clinical parameters were comparable between groups. Group 5 had the highest proportion of pretransplant liver biopsy (85%), with only 1 graft showing macrovesicular steatosis > 30%, and the lowest ischemia time. Five-year graft survival was significantly higher in group 1 (75%) versus groups 3 (60%) and 4 (62%; P = 0.01 and P = 0.001, respectively) and in group 5 (81%) versus groups 3 and 4 (P = 0.04 and P = 0.01, respectively). Donor age of 60-79 years, recipient hepatitis C virus-positive status, Model for End-Stage Liver Disease score > or = 25, and emergency LT were predictors of poor survival. In hepatitis C virus-positive patients, 5-year graft survival was 72% in group 1, 85% in group 2, 52% in group 3, 65% in group 4, and 71% in group 5 (group 1 versus group 3, P = 0.04; group 2 versus group 3, P = 0.03). In conclusion, older donor grafts managed with routine graft biopsy and short ischemia time may work effectively, regardless of the severity of the recipient's liver disease.