Ischemic-type biliary complications after orthotopic liver transplantation

From Patients to Providers: Assessing Impact of Normothermic Machine Perfusion on Liver Transplant Practices in the US

BACKGROUND

Normothermic machine perfusion (NMP) of livers allows for the expansion of the donor pool and minimization of posttransplant complications. Results to date have focused on both donor and recipient outcomes, but there remains potential for NMP to also impact transplant providers.

STUDY DESIGN

Using United Network for Organ Sharing Standard Transplant Analysis file data, adult deceased donors who underwent transplantation between January 1, 2016, and December 31, 2022, were identified. Transplanted livers were divided by preservation methods (static cold storage [SCS] and NMP) and case time (day-reperfusion 8 am to 6 pm ). Patient factors, transplant characteristics, and short-term outcomes were analyzed between Mahalanobis-metric-matched groups.

RESULTS

NMP livers represented 742 (1.4%) of 52,132 transplants. NMP donors were more marginal with higher Donor Risk Index scores (1.78 ± 0.50 NMP vs 1.49 ± 0.38 SCS, p < 0.001) and donation after cardiac death frequency (36.9% vs 8.4%, p < 0.001). NMP recipients more often had model for end-stage liver disease (MELD) exception status (29.9% vs 23.4%, p < 0.001), lower laboratory MELD scores (20.7 ± 9.7 vs 24.3 ± 10.9, p < 0.001), and had been waitlisted longer (111.5 [21.0 to 307.0] vs 60.0 [9.0 to 245.0] days, p < 0.001). One-year graft survival (90.2% vs 91.6%, p = 0.505) was similar between groups, whereas length of stay was lower for NMP recipients (8.0 [6.0 to 14.0] vs 10.0 [6.0 to 16.0], p = 0.017) after adjusting for confounders. Notably, peak case volume occurred at 11 am with NMP livers (vs 9 pm with SCS). Overall, a higher proportion of transplants was performed during daytime hours with NMP (51.5% vs 43.0%, p < 0.001).

CONCLUSIONS

NMP results in increased use of marginal allografts, which facilitated transplantation in lower laboratory MELD recipients who have been waitlisted longer and often have exception points. Importantly, NMP also appeared to shift peak caseloads from nighttime to daytime, which may have significant effects on the quality of life for the entire liver transplant team.

The Role of Microbiota in Liver Transplantation and Liver Transplantation-Related Biliary Complications

Liver transplantation as a treatment option for end-stage liver diseases is associated with a relevant risk for complications. On the one hand, immunological factors and associated chronic graft rejection are major causes of morbidity and carry an increased risk of mortality due to liver graft failure. On the other hand, infectious complications have a major impact on patient outcomes. In addition, abdominal or pulmonary infections, and biliary complications, including cholangitis, are common complications in patients after liver transplantation and can also be associated with a risk for mortality. Thereby, these patients already suffer from gut dysbiosis at the time of liver transplantation due to their severe underlying disease, causing end-stage liver failure. Despite an impaired gut-liver axis, repeated antibiotic therapies can cause major changes in the gut microbiome. Due to repeated biliary interventions, the biliary tract is often colonized by several bacteria with a high risk for multi-drug resistant germs causing local and systemic infections before and after liver transplantation. Growing evidence about the role of gut microbiota in the perioperative course and their impact on patient outcomes in liver transplantation is available. However, data about biliary microbiota and their impact on infectious and biliary complications are still sparse. In this comprehensive review, we compile the current evidence for the role of microbiome research in liver transplantation with a focus on biliary complications and infections due to multi-drug resistant germs.

Liver Transplantation in Recipients With a Positive Crossmatch: A Retrospective Single-Center Match-Pair Analysis

A positive crossmatch (XM+) is considered a contraindication to solid abdominal organ transplantation except liver transplantation (LT). Conflicting reports exist regarding the effects of XM+ on post-transplant outcomes. The goal of this retrospective single-center analysis is to evaluate the influence of XM+ on relevant outcome parameters such as survival, graft rejection, biliary and arterial complications. Forty-nine adult patients undergoing LT with a XM+ between 2002 and 2017 were included. XM+ LT recipients were matched 1:2 with crossmatch negative (XM-) LT recipients based on the balance of risk (BAR) score. Patient and graft survival were compared using Kaplan-Meier survival analysis and the log-rank test. Comparative analysis of clinical outcomes in XM+ and XM- groups were conducted. Patient and graft survival were similar in XM+ and XM- patients. Rejection episodes did not differ either. Recipients with a strong XM+ were more likely to develop a PCR+ CMV infection. A XM+ was not associated with a higher incidence of biliary or arterial complications. Donor age, cold ischemia time, PCR+ CMV infection and a rejection episode were associated with the occurrence of ischemic type biliary lesions. A XM+ has no effects on patient and graft survival or other relevant outcome parameters following LT.

Four Decades of Clinical Liver Transplantation Research: Results of a Comprehensive Bibliometric Analysis

BACKGROUND

Nearly 40 y have passed since the 1983 National Institutes of Health Consensus-Development-Conference, which has turned liver transplantation (LT) from a clinical experiment into a routine therapeutic modality. Since' clinical LT has changed substantially. We aimed to comprehensively analyze the publication trends in the most-cited top-notch literature in LT science over a 4-decade period.

METHODS

A total of 106 523 items were identified between January 1981 and May 2021 from the Web of Science Core Collection. The top 100 articles published were selected using 2 distinct citation-based strategies to minimize bias. Various bibliometric tools were used for data synthesis and visualization.

RESULTS

The citation count for the final dataset of the top 100 articles ranged from 251 to 4721. Most articles were published by US authors (n = 61). The most prolific institution was the University of Pittsburgh (n = 15). The highest number of articles was published in Annals of Surgery, Hepatology, and Transplantation ; however, Hepatology publications resulted in the highest cumulative citation of 9668. Only 10% of the articles were classified as evidence level 1. Over 90% of first/last authors were male. Our data depict the evolution of research focus over 40 y. In part, a disproportional flow of citations was observed toward already well-cited articles. This might also project a slowed canonical progress, which was described in other fields of science.

CONCLUSIONS

This study highlights key trends based on a large dataset of the most-cited articles over a 4-decade period. The present analysis not only provides an important cross-sectional and forward-looking guidance to clinicians, funding bodies, and researchers but also draws attention to important socio-academic or demographic aspects in LT.

Are short-term complications associated with poor allograft and patient survival after liver transplantation? A systematic review of the literature and expert panel recommendations

BACKGROUND

Maximizing patient and allograft survival after liver transplant (LT) is important from both a patient care and organ utilization perspective. Although individual studies have addressed the effects of short-term post-LT complications on a limited scale, there has not been a systematic review of the literature formally assessing the potential effects of early complications on long-term outcomes.

OBJECTIVES

To identify whether short-term complications after LT affect allograft and overall survival, to identify short-term complications of particular clinical interest and significance, and to provide recommendations to improve post-LT graft and patient survival.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central.

METHODS

A systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel.

RESULTS

The literature review and analysis provided show that short-term complications have a large impact on allograft and patient survival after LT. The complications with the strongest effect on survival are acute kidney injury (AKI), biliary complications, and early allograft dysfunction (EAD).

CONCLUSION

This panel recommends taking measures to reduce the risk and incidence of short-term complications post-LT. Clinicians should pay particular attention to preventing or ameliorating AKI, biliary complications, and EAD (Quality of evidence; Moderate | Grade of Recommendation; Strong).

Protective mechanisms and current clinical evidence of hypothermic oxygenated machine perfusion (HOPE) in preventing post-transplant cholangiopathy

The development of cholangiopathies after liver transplantation impacts on the quality and duration of graft and patient survival, contributing to higher costs as numerous interventions are required to treat strictures and infections at the biliary tree. Prolonged donor warm ischaemia time in combination with additional cold storage are key risk factors for the development of biliary strictures. Based on this, the clinical implementation of dynamic preservation strategies is a current hot topic in the field of donation after circulatory death (DCD) liver transplantation. Despite various retrospective studies reporting promising results, also regarding biliary complications, there are only a few randomised-controlled trials on machine perfusion. Recently, the group from Groningen has published the first randomised-controlled trial on hypothermic oxygenated perfusion (HOPE), demonstrating a significant reduction of symptomatic ischaemic cholangiopathies with the use of a short period of HOPE before DCD liver implantation. The most likely mechanism for this important effect, also shown in several experimental studies, is based on mitochondrial reprogramming under hypothermic aerobic conditions, e.g. exposure to oxygen in the cold, with a controlled and slow metabolism of ischaemically accumulated succinate and simultaneous ATP replenishment. This unique feature prevents mitochondrial oxidative injury and further downstream tissue inflammation. HOPE treatment therefore supports livers by protecting them from ischaemia-reperfusion injury (IRI), and thereby also prevents the development of post-transplant biliary injury. With reduced IRI-associated inflammation, recipients are also protected from activation of the innate immune system, with less acute rejections seen after HOPE.

Multimodality Imaging after Liver Transplant: Top 10 Important Complications

Patients who have undergone liver transplant are now regularly seen in day-to-day radiology practice. All surgical techniques for liver transplant require arterial, portal venous, hepatic venous and caval, and biliary anastomoses. This review is focused on the 10 "not to be missed" complications of liver transplant that affect the health and life of the graft and graft recipient. Arterial complications are the most common and devastating. Early hepatic artery thrombosis may be catastrophic because the biliary tree is solely dependent on the hepatic artery after transplant and collateral vessels have not yet formed. In contrast, delayed hepatic artery thrombosis may be more insidious as collateral arteries develop. US findings of delayed hepatic artery thrombosis may be similar to those of hepatic artery stenosis and celiac artery stenosis. Splenic artery steal syndrome is an increasingly recognized cause of graft ischemia. Venous complications are much less common. Hepatic venous and caval complications are notable for their increased incidence in living-donor and pediatric transplants. Biliary complications often result from arterial ischemia. Biliary cast syndrome is a notable example in which ischemic biliary mucosa sloughs into and obstructs the duct lumens. Neoplasms also may occur within the hepatic graft and may be due to recurrent malignancy, posttransplant lymphoproliferative disorder, or metastases. US is the initial imaging modality of choice, particularly in the acute postoperative setting. Further evaluation with contrast-enhanced US, CT, or MRI; catheter angiography; endoscopic retrograde cholangiopancreatography; and/or nuclear medicine studies is performed as needed. An invited commentary by Bhargava is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

The Prognostic Utility of Intraoperative Allograft Vascular Inflow Measurements in Donation After Circulatory Death Liver Transplantation

Donation after circulatory death (DCD) liver transplantation improves deceased donor liver use and decreases waitlist burden, albeit at an increased risk of biliary complications and inferior graft survival. Employing liver vascular inflow measurements intraoperatively permits allograft prognostication. However, its use in DCD liver transplantation is hitherto largely unknown and further explored here. DCD liver transplantation patient records at a single center from 2005 to 2018 were retrospectively scrutinized. Intraoperative flow data and relevant donor parameters were analyzed against endpoints of biliary events and graft survival. A total of 138 cases were chosen. The incidence of cumulative biliary complications was 38%, the majority of which were anastomotic strictures and managed successfully by endoscopic means. The ischemic cholangiopathy rate was 6%. At median thresholds of a portal vein (PV) flow rate of <92 mL/minute/100 g and buffer capacity (BC) of >0.04, both variables were independently associated with risk of biliary events (P = 0.01 and 0.04, respectively). Graft survival was 90% at 12 months and 75% at 5 years. Cox regression analysis revealed a PV flow rate of <50 mL/minute/100 g as predictive of poorer graft survival (P = 0.01). Furthermore, 126 of these DCD livers were analyzed against a propensity-matched group of 378 contemporaneous donation after brain death liver allografts (1:3), revealing significantly higher rates (P < 0.001) of both early allograft dysfunction (70% versus 30%) and biliary complications (37% versus 20%) in the former group. Although flow data were comparable between both sets, PV flow and BC were predictive of biliary events only in the DCD cohort. Intraoperative inflow measurements therefore provide valuable prognostication on biliary/graft outcomes in DCD liver transplantation, can help inform graft surveillance, and its routine use is recommended.

Ultrasound-Based Multimodal Imaging Predicting Ischemic-Type Biliary Lesions After Living-Donor Liver Transplantation

BACKGROUND

Ischemic-type biliary lesions (ITBL) are accepted as the most incomprehensible biliary complications after living-donor liver transplantation (LDLT). Early predicting the development of ITBL in pediatric patients permits more preventive strategies. However, few studies have focused on the early prediction of ITBL.

OBJECTIVE

This study aimed to establish a nomogram including ultrasound-based multimodal imaging to predict ITBL in children with biliary atresia (BA) within 2 years after receiving LDLT.

METHODS

The records of 94 BA children with at least one year of follow-up after LDLT were reviewed retrospectively. They were randomly divided into a training cohort for constructing a nomogram (n=64) and a validation cohort (n=30). In the training cohort, patients diagnosed as ITBL were included in the ITBL group and those without any vascular and biliary complication were included in the non-ITBL group. Multivariate Cox regression was used for the establishment of the nomogram in predicting the risk of ITBL within 2 years post-LDLT. The discrimination and calibration of the nomogram were internally and externally validated. The performances of the nomogram and the individual components were compared by the area under the curve (AUC) of receiver operating characteristic (ROC) curve.

RESULTS

In the training cohort, 18 BA children were included in the ITBL group and 46 were in the non-ITBL group. Last pediatric end-stage liver disease (PELD) score, gamma-glutamyl transpeptidase (GGT), resistive index (RI), and liver stiffness measurement (LSM) were the independent predictors for the development of ITBL within 2 years post-LDLT. The nomogram incorporating these independent predictors showed good discrimination and calibration by the internal and external validation. Its performance was better than any individual component in predicting the prognosis (P < 0.05).

CONCLUSION

The established nomogram may be used to predict the risk of ITBL within 2 years post-LDLT in BA children.

Intensified Endoscopic Evaluation for Biliary Complications After Orthotopic Liver Transplantation

Background

Biliary complications are common causes of morbidity and mortality after liver transplantation.

Material/Methods

From 2013 to 2018, 102 whole-organ liver transplantations were conducted in our department. Patients were closely monitored for biliary complication development. In all suspected cases, patients underwent either endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangial drainage. Patients’ demographic characteristics, preexisting conditions, and perioperative characteristics, as well as morbidity and mortality, were analyzed. Risk factors for 1-year survival were calculated.

Results

Of the 102 patients, 43 (42%) experienced biliary complications. In comparison with patients without biliary complications, patients with biliary complications exhibited the following risk factors: underlying liver disease (viral hepatitis; P=0.009), blood group A (P=0.005), and previous abdominal surgery (P=0.037). Neither perioperative characteristics, especially duration of cold ischemia (P=0.86), nor postoperative course differed between patients with and without biliary complications. Risk factors for mortality within 1 year were cirrhosis caused by entities other than viral hepatitis (P=0.017), cardiac comorbidities (P=0.019), re-transplantation (P=0.032), and reduced organ weight (P=0.002). Biliary complications, postoperative hemorrhage, primary nonfunction, and repeated surgery worsened outcome; moreover, serum bilirubin trough in the first 30 days after transplantation might be prognostic for mortality (P=0.043).

Conclusions

Biliary complications adversely affect outcome after liver transplantation. Neither frequency nor outcome of biliary complications was improved by intensified endoscopic evaluation. Patients on the waiting list for liver transplants should also be closely monitored for cardiac comorbidities.

Biliary calprotectin, lactoferrin and dimeric pyruvate kinase after liver transplantation are associated with biliary damage and graft survival in a case-control study

BACKGROUND

After liver transplantation (LT), biliary complications are associated with reduced graft survival. We tested inflammation markers for their association with biliary damage and graft loss in bile.

MATERIAL AND METHODS

The study design was a retrospective case-control study. Calprotectin, lactoferrin and pyruvate kinase were measured in endoscopically retrieved bile with ELISA.

RESULTS

Calprotectin and lactoferrin were significantly higher in bile of ischemic-type biliary lesions and donor duct non-anastomotic strictures than in control, bile leakage, Cytomegalovirus infection, anastomotic stricture or acute cellular rejection patients (p<0.001) independent of serum liver values at endoscopy. Calprotectin (p=0.02) was independently associated with retransplantation free survival in multivariate analysis, as was γGT (p=0.03) but not ERC radiographic classification of the bile duct or cold ischemia time.

CONCLUSION

Calprotectin and lactoferrin are bile markers for biliary damage and are associated with re-transplantation free survival. They can differentiate progressive biliary damage from non-biliary liver value alterations after LT.

Favorable Outcomes After Liver Transplantation With Normothermic Regional Perfusion From Donors After Circulatory Death: A Single-center Experience

BACKGROUND

Controlled donation after circulatory death (cDCD) has been associated with a high incidence of ischemic cholangiopathy and other perioperative complications. In an attempt to avoid these complications, we implemented an active protocol of cDCD liver transplant (LT) with normothermic regional perfusion (NRP) preservation.

METHODS

This is a descriptive analysis of data collected from a prospective date base of cDCD LT preserved with NRP from January 2015 to June 2017 with a minimum follow up of 9 months.

RESULTS

Fifty-seven potential cDCD donors were connected to the NRP system. Of these, 46 livers were transplanted over a 30-month period (80% liver recovery rate). The median posttransplant peak in alanine transaminase was 1136 U/L (220-6683 U/L). Seven (15%) patients presented postreperfusion syndrome and 11 (23%) showed early allograft dysfunction. No cases of ischemic cholangiopathy were diagnosed, and no graft loss was observed over a medium follow-up period of 19 months. Of note, 13 donors were older than 65 years, achieving comparable perioperative and midterm results to younger donors.

CONCLUSIONS

As far as we know, this represents the largest published series of cDCD LT with NRP preservation. Our results demonstrate that cDCD liver grafts preserved with NRP appear far superior to those obtained by the conventional rapid recovery technique.

A Review on the Management of Biliary Complications after Orthotopic Liver Transplantation

Orthotopic liver transplantation is the definitive treatment for end-stage liver disease and hepatocellular carcinomas. Biliary complications are the most common complications seen after transplantation, with an incidence of 10-25%. These complications are seen both in deceased donor liver transplant and living donor liver transplant. Endoscopic treatment of biliary complications with endoscopic retrograde cholangiopancreatography (commonly known as ERCP) has become a mainstay in the management post-transplantation. The success rate has reached 80% in an experienced endoscopist's hands. If unsuccessful with ERCP, percutaneous transhepatic cholangiography can be an alternative therapy. Early recognition and treatment has been shown to improve morbidity and mortality in post-liver transplant patients. The focus of this review will be a learned discussion on the types, diagnosis, and treatment of biliary complications post-orthotopic liver transplantation.

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.

The efficacy of extracorporeal membrane oxygenation in liver transplantation from non-heart-beating donors: A systemic review and meta-analysis

BACKGROUND

A systematic review and meta-analysis was made to see whether extracorporeal membrane oxygenation (ECMO) in liver transplantation could improve non-heart-beating donors (NHBDs) recipients' outcomes compared with donors after brain death (DBDs) recipients.

METHODS

We searched MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials for eligible studies. The study eligible criteria are cohort or case-control studies using ECMO in all NHBDs; studies involved a comparison group of DBDs; and studies evaluated 1-year graft and patient survival rate in NHBDs and DBDs groups.

RESULTS

Four studies with 704 patients fulfilled the inclusion criteria. The pooled odds ratio (OR) of 1-year patient survival rate in NHBDs recipients compared with DBDs recipients was 0.8 (95% confidence interval [CI], 0.41-1.55). The pooled OR of 1-year graft survival rate in NHBDs recipients compared with DBDs recipients was 0.46 (95% CI, 0.26-0.81). NHBDs recipients were at greater risks to the occurrence of primary nonfunction (PNF) (OR = 7.12, 95% CI, 1.84-27.52) and ischemic cholangiopathy (IC) (OR = 9.46, 95% CI, 2.76-32.4) than DBDs recipients.

CONCLUSIONS

ECMO makes 1-year patient survival acceptable in NHBDs recipients. One-year graft survival rate was lower in NHBDs recipients than in DBDs recipients. Compared with DBDs recipients, the risks to develop PNF and IC were increased among NHBDs recipients.

Impact of Machine Perfusion on Biliary Complications after Liver Transplantation

We describe in this review the different types of injuries caused to the biliary tree after liver transplantation. Furthermore, we explain underlying mechanisms and why oxygenated perfusion concepts could not only protect livers, but also repair high-risk grafts to prevent severe biliary complications and graft loss. Accordingly, we summarize experimental studies and clinical applications of machine liver perfusion with a focus on biliary complications after liver transplantation. Key points: (1) Acute inflammation with subsequent chronic ongoing liver inflammation and injury are the main triggers for cholangiocyte injury and biliary tree transformation, including non-anastomotic strictures; (2) Hypothermic oxygenated perfusion (HOPE) protects livers from initial oxidative injury at normothermic reperfusion after liver transplantation. This is a unique feature of a cold oxygenation approach, which is effective also end-ischemically, e.g., after cold storage, due to mitochondrial repair mechanisms. In contrast, normothermic oxygenated perfusion concepts protect by reducing cold ischemia, and are therefore most beneficial when applied instead of cold storage; (3) Due to less downstream activation of cholangiocytes, hypothermic oxygenated perfusion also significantly reduces the development of biliary strictures after liver transplantation.

Preliminary results from the use of intraoperative real-time biliary oxygen monitoring in liver transplantation

BACKGROUND AND AIMS

Biliary anastomosis is a frequent area of complications after liver transplantation (LT) and a potential area of "microangiopathy". The concept of a "marginal bile duct" is unexplored. The main aim was to make a preliminary evaluation of the utility of an innovative real-time oxygen microtension (pO2mt) testing device for the assessment of bile duct viability during LT and to correlate these pO2mt values with microvascular tissue quality by histopathology and outcomes.

PATIENTS AND METHODS

Observational prospective cohort study with 23 patients. Oxygen microtension measurements were made placing a micropO2 probe in different areas of recipient and donor's bile duct intraoperative.

RESULTS

Mean pO2mt in the graft bile duct at the level of the anastomosis 103.82 (31-157) mm Hg, being 121.52 (55-174) mm Hg 1.5 cm proximal to the hilar plate (P < 0.001). Mean pO2mt in the recipient's bile duct was 117.87 (62-185) mm Hg, while a value of 137.30 (81-198) mm Hg was observed 1.5 cm distal to the anastomosis (P < 0.001). Cystic duct resection (12 cases) was also related with higher pO2mt values at anastomosis [117.8 (93-157) vs 88.54 (31-124) mm Hg] and distal to anastomosis [135.6 (111-174) vs 106.2 (55-133) mm Hg; P < 0.001]. Patients with 1-, 3-, and 12-month biliary complications had significantly lower pO2mt in the intraoperative measurements.

CONCLUSION

Our preliminary results show that distal borders of donor and recipient bile ducts may be low-vascularized areas. Tissue pO2mt is significantly higher in areas close to the hilar plate and to the duodenum in donor and recipient's sides, respectively. Bile duct injury and biliary complications are associated with worse tissue pO2mt.

Impact of machine perfusion of the liver on post-transplant biliary complications: A systematic review

AIM

To review the clinical impact of machine perfusion (MP) of the liver on biliary complications post-transplantation, particularly ischaemic-type biliary lesions (ITBL).

METHODS

This systematic review was performed in accordance with the Preferred Reporting Systematic Reviews and Meta-Analysis (PRISMA) protocol. The following databases were searched: PubMed, MEDLINE and Scopus. The keyword “liver transplantation” was used in combination with the free term “machine perfusion”. Clinical studies reporting results of transplantation of donor human livers following ex situ or in situ MP were analysed. Details relating to donor characteristics, recipients, technique of MP performed and post-operative biliary complications (ITBL, bile leak and anastomotic strictures) were critically analysed.

RESULTS

Fifteen articles were considered to fit the criteria for this review. Ex situ normothermic MP was used in 6 studies, ex situ hypothermic MP in 5 studies and the other 4 studies investigated in situ normothermic regional perfusion (NRP) and controlled oxygenated rewarming. MP techniques which have per se the potential to alleviate ischaemia-reperfusion injury: Such as hypothermic MP and NRP, have also reported lower rates of ITBL. Other biliary complications, such as biliary leak and anastomotic biliary strictures, are reported with similar incidences with all MP techniques. There is currently less clinical evidence available to support normothermic MP as a mitigator of biliary complications following liver transplantation. On the other hand, restoration of organ to full metabolism during normothermic MP allows assessment of hepatobiliary function before transplantation, although universally accepted criteria have yet to be validated.

CONCLUSION

MP of the liver has the potential to have a positive impact on post-transplant biliary complications, specifically ITBL, and expand extended criteria donor livers utilisation.

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.

Compared efficacy of preservation solutions on the outcome of liver transplantation: Meta-analysis

AIM

To compare the effects of the four most commonly used preservation solutions on the outcome of liver transplantations.

METHODS

A systematic literature search was performed using MEDLINE, Scopus, EMBASE and the Cochrane Library databases up to January 31st, 2017. The inclusion criteria were comparative, randomized controlled trials (RCTs) for deceased donor liver (DDL) allografts with adult and pediatric donors using the gold standard University of Wisconsin (UW) solution or histidine-tryptophan-ketoglutarate (HTK), Celsior (CS) and Institut Georges Lopez (IGL-1) solutions. Fifteen RCTs (1830 livers) were included; the primary outcomes were primary non-function (PNF) and one-year post-transplant graft survival (OGS-1).

RESULTS

All trials were homogenous with respect to donor and recipient characteristics. There was no statistical difference in the incidence of PNF with the use of UW, HTK, CS and IGL-1 (RR = 0.02, 95%CI: 0.01-0.03, P = 0.356). Comparing OGS-1 also failed to reveal any difference between UW, HTK, CS and IGL-1 (RR = 0.80, 95%CI: 0.80-0.80, P = 0.369). Two trials demonstrated higher PNF levels for UW in comparison with the HTK group, and individual studies described higher rates of biliary complications where HTK and CS were used compared to the UW and IGL-1 solutions. However, the meta-analysis of the data did not prove a statistically significant difference: the UW, CS, HTK and IGL-1 solutions were associated with nearly equivalent outcomes.

CONCLUSION

Alternative solutions for UW yield the same degree of safety and effectiveness for the preservation of DDLs, but further well-designed clinical trials are warranted.

Ischemic Type Biliary Lesions in Histidine-Tryptophan-Ketoglutarate (HTK) Preserved Liver Grafts

Ischemic type biliary lesions lead to considerable morbidity following orthotopic liver transplantation. The exact pathogenesis is unknown. One major hypothesis is that insufficient perfusion of the arterial vessels of the biliary tree, especially under perfusion with the high viscous University of Wisconsin solution, might be responsible for ischemic type biliary lesions. Due to low viscosity, HTK solution is reported to have a lower incidence of biliary complications. However, there is no data concerning ischemic type biliary lesions in HTK preserved livers. In this paper we report our results after orthotopic liver transplantation with special regard to ischemic type biliary lesions in liver grafts preserved with HTK solution. Between 09/1997 and 01/2005 300 liver transplantations were performed in our center. Thirty-two (10.7%) liver grafts were preserved with HTK solution, 268 (89.3%) were preserved with UW solution. Six and 43 grafts showed ischemic type biliary lesions after orthotopic liver transplantation in HTK- (18.8%) and UW- (16.0%) groups, respectively (p=0.696). There was no statistical significant difference between the two groups. Donor related factors, recipient age, indication for transplantation, transplantation technique, immunosuppression and ischemia time were comparable in both groups.

Ischemic type biliary lesions occurred with the same frequency in HTK preserved livers compared to UW preserved organs. We suggest that low viscosity of the preservation fluid by itself does not guarantee reliable perfusion of the small arteries of a liver graft and a pressure perfusion might be beneficial even in HTK solution.

Waitlist Outcomes for Patients Relisted Following Failed Donation After Cardiac Death Liver Transplant: Implications for Awarding Model for End-Stage Liver Disease Exception Scores

Understanding of outcomes for patients relisted for ischemic cholangiopathy following a donation after cardiac death (DCD) liver transplant (LT) will help standardization of a Model for End-Stage Liver Disease exception scheme for retransplantation. Early relisting (E-RL) for DCD graft failure caused by primary nonfunction (PNF) or hepatic artery thrombosis (HAT) was defined as relisting ≤14 days after DCD LT, and late relisting (L-RL) due to biliary complications was defined as relisting 14 days to 3 years after DCD LT. Of 3908 DCD LTs performed nationally between 2002 and 2016, 540 (13.8%) patients were relisted within 3 years of transplant (168 [4.3%] in the E-RL group, 372 [9.5%] in the L-RL group). The E-RL and L-RL groups had waitlist mortality rates of 15.4% and 10.5%, respectively, at 3 mo and 16.1% and 14.3%, respectively, at 1 year. Waitlist mortality in the L-RL group was higher than mortality and delisted rates for patients with exception points for both hepatocellular carcinoma (HCC) and hepatopulmonary syndrome (HPS) at 3- to 12-mo time points (p < 0.001). Waitlist outcomes differed in patients with early DCD graft failure caused by PNF or HAT compared with those with late DCD graft failure attributed to biliary complications. In L-RL, higher rates of waitlist mortality were noted compared with patients listed with exception points for HCC or HPS.

Liver Preservation by Aortic Perfusion Alone Compared With Preservation by Aortic Perfusion and Additional Arterial Ex Situ Back-Table Perfusion With Histidine-Tryptophan-Ketoglutarate Solution: A Prospective, Randomized, Controlled, Multicenter Study

Background

Arterial ex situ back-table perfusion (BP) reportedly reduces ischemic-type biliary lesion after liver transplantation. We aimed to verify these findings in a prospective investigation.

Methods

Our prospective, randomized, controlled, multicenter study involved livers retrieved from patients in 2 German regions, and compared the outcomes of standard aortic perfusion to those of aortic perfusion combined with arterial ex situ BP. The primary endpoint was the incidence of ischemic-type biliary lesions over a follow-up of 2 years after liver transplantation, whereas secondary endpoints included 2-year graft survival, initial graft damage as reflected by transaminase levels, and functional biliary parameters at 6 months after transplantation.

Results

A total of 75 livers preserved via standard aortic perfusion and 75 preserved via standard aortic perfusion plus arterial BP were treated using a standardized protocol. The incidence of clinically apparent biliary lesions after liver transplantation (n = 9 for both groups; P = 0.947), the 2-year graft survival rate (standard aortic perfusion, 74%; standard aortic perfusion plus arterial BP, 68%; P = 0.34), and incidence of initial graft injury did not differ between the 2 perfusion modes. Although 33 of the 77 patients with cholangiography workups exhibited injured bile ducts, only 10 had clinical symptoms.

Conclusions

Contrary to previous findings, the present study indicated that additional ex situ BP did not prevent ischemic-type biliary lesions or ischemia-reperfusion injury after liver transplantation. Moreover, there was considerable discrepancy between cholangiography findings regarding bile duct changes and clinically apparent cholangiopathy after transplantation, which should be considered when assessing ischemic-type biliary lesions.

Post-transplant cholangiopathy: Classification, pathogenesis, and preventive strategies

Biliary complications are the most frequent cause of morbidity, re-transplantation, and even mortality after liver transplantation. In general, biliary leakage and anastomotic and non-anastomotic biliary strictures (NAS) can be recognized. There is no consensus on the exact definition of NAS and different names and criteria have been used in literature. We propose to use the term post-transplant cholangiopathy for the spectrum of abnormalities of large donor bile ducts, that includes NAS, but also intraductal casts and intrahepatic biloma formation, in the presence of a patent hepatic artery. Combinations of these manifestations of cholangiopathy are not infrequently found in the same liver and ischemia-reperfusion injury is generally considered the common underlying mechanism. Other factors that contribute to post-transplant cholangiopathy are biliary injury due to bile salt toxicity and immune-mediated injury. This review provides an overview of the various types of post-transplant cholangiopathy, the presumed pathogenesis, clinical implications, and preventive strategies.

Comparison of longterm outcomes and quality of life in recipients of donation after cardiac death liver grafts with a propensity-matched cohort

The use of liver grafts from donation after cardiac death (DCD) has been limited due to the increased rate of graft failure, mostly related to ischemic cholangiopathy (IC). It is our hypothesis that longterm outcomes and quality of life (QOL) similar to patients undergoing liver transplantation (LT) with donation after brain death (DBD) can be achieved. Clinical outcomes of all patients undergoing DCD LT (n = 300) between 1998 and 2015 were compared with a propensity score-matched cohort of patients undergoing DBD LT (n = 300). Patients were contacted for a follow-up questionnaire and short-form (SF)-12 QOL Survey administration. Median follow-up was >5 years. Graft survival at 1-, 3-, and 5-years was 83.8%, 75.5%, and 70.1% in the DCD LT group and 88.4%, 80.3%, and 73.9% in the DBD LT group (P = 0.27). Patient survival at 1-, 3-, and 5-years was 92.3%, 86.1%, and 80.3% in the DCD LT group and 92.3%, 85.1%, and 79.5% in the DBD LT group (P = 0.81). IC developed in 11.7% and 2% of patients in the DCD LT group and DBD LT group, respectively (P < 0.001). DCD LT recipients who developed IC had inferior graft survival compared with both the DCD non-IC group (P < 0.001) and the DBD LT group (P < 0.001); no difference in graft survival was observed between the DCD non-IC group and the DBD LT group (P = 0.50). Physical and Mental Composite Scores on the SF-12 QOL questionnaire were similar between the DCD LT and DBD LT groups (44.0 versus 45.4; P = 0.34 and 51.9 versus 52.2; P = 0.83), respectively. Similar longterm survival and QOL scores can be achieved between DCD LT and DBD LT. Prevention of IC in DCD LT yields excellent graft and patient survival with virtually no difference compared with DBD LT. Liver Transplantation 23 342-351 2017 AASLD.

Endoscopic approach for management of biliary strictures in liver transplant recipients: A systematic review and meta-analysis

The most common biliary complication after liver transplantation is anastomotic stricture (AS) and it can occur isolated or in combination with other complications. Liver graft from a cadaveric donor or a living donor has an influence on the incidence of biliary strictures as well as on the response to endoscopic treatment. Endoscopic treatment using balloon dilation and insertion of biliary stents by endoscopic retrograde cholangiopancreatography (ERCP) is the initial approach to these complications.

AIM

The aim of this article is to compare different endoscopic techniques to treat post-liver transplantation biliary strictures.

METHODS

The search was carried out on MEDLINE, EMBASE, Scielo-LILACS and Cochrane Library databases through June 2015. A total of 1100 articles were retrieved. Ten clinical trials were analyzed, and seven were included in the meta-analysis.

CONCLUSIONS

The endoscopic treatment of AS was equally effective when compared the use of fully covered self-expandable metal stents (FCSEMS) vs. plastic stents, but the use of FCSEMS was associated with a lower complication risk. The treatment of AS with balloon dilation or balloon dilation associated with plastic stents presented similar results. Deceased donor liver transplantation reduced the risk of biliary stenosis and the endoscopic treatment in these patients was more effective when compared with Living donor liver transplantation.

Donations After Circulatory Death in Liver Transplant

The supply of liver grafts for treatment of end-stage liver disease continues to fall short of ongoing demands. Currently, most liver transplants originate from donations after brain death. Enhanced utilization of the present resources is prudent to address the needs of the population. Donation after circulatory or cardiac death is a mechanism whereby the availability of organs can be expanded. Donations after circulatory death pose unique challenges given their exposure to warm ischemia. Technical principles of donations after circulatory death procurement and pertinent studies investigating patient outcomes, graft outcomes, and complications are highlighted in this review. We also review associated risk factors to suggest potential avenues to achieve improved outcomes and reduced complications. Future considerations and alternative techniques of organ preservation are discussed, which may suggest novel strategies to enhance preservation and donor expansion through the use of marginal donors. Ultimately, without effective measures to bolster organ supply, donations after circulatory death should remain a consideration; however, an understanding of inherent risks and limitations is necessary.

Risk factors for and management of ischemic-type biliary lesions following orthotopic liver transplantation: A single center experience

INTRODUCTION

Biliary complications can cause morbidity, graft loss, and mortality after liver transplantation. The most troublesome biliary complications are ischemic-type biliary lesions (ITBL), which occur since transplants can now be performed after the donor has undergone circulatory death. The exact origin of this type of biliary complication remains unknown.

MATERIAL AND METHODS

A total of 528 patients were retrospectively analyzed following liver transplantation after excluding 30 patients with primary sclerosing cholangitis and those lost to follow-up from January 2007 to January 2014. The incidence of and risk factors for ITBL were evaluated.

RESULTS

Cold ischemia time (CIT) (P = 0.042) and warm ischemia time (WIT) (P = 0.006) were found to be independent risk factors for the development of ITBL. Use of the cytochrome P450 (CYP) 3A5 genotype assay to guide individualization of immunosuppressive medications resulted in significantly fewer ITBL (P = 0.027. Autoimmune hepatitis might be a risk factor for ITBL, as determined using univariate analysis (P = 0.047).

CONCLUSIONS

Efforts should be taken to minimize risk factors associated with ITBL, such as CIT and WIT. The CYP3A5 genotype assay should be used to guide selection of immunosuppressive therapy in an effort to reduce the occurrence of ITBL.

Von Willebrand factor and alkaline phosphatase predict re-transplantation-free survival after the first liver transplantation

BACKGROUND

After liver transplantation (LT), there are liver-related, infectious and cardiovascular complications that contribute to reduced graft survival. These conditions are associated with an increase in the Von Willebrand factor antigen (VWF-Ag), which was previously correlated with survival in cirrhotic patients.

OBJECTIVE

Evaluate VWF-Ag as a predictive marker of re-transplantation-free survival in patients after LT.

METHODS

We measured VWF-Ag in patients after first LT and then followed them prospectively with regard to the primary endpoint, namely re-transplantation-free survival.

RESULTS

There were 6 out of 80 patients who died or received re-LT during follow-up. In these patients, the median VWF-Ag was 510.6%, which was significantly higher (p = 0.001) than in the patients who were alive at the end of follow-up (with a median VWF-Ag = 186.8%). At a cut-off of 286.8%, VWF-Ag was significantly correlated with re-transplantation-free survival (p < 0.001). VWF-Ag was independently associated with re-transplantation-free survival in a multivariate analysis; as was alkaline phosphatase (ALP), but not the model of end-stage liver disease (MELD) score, donor age, nor cold ischemia time. A score combining VWF-Ag and ALP showed an impressive capability in the receiver operating characteristic (ROC) analysis (with area under the curve (AUC) = 0.958) to distinguish between patients with regard to the primary endpoint.

CONCLUSIONS

VWF-Ag is a non-invasive marker that can predict outcome in patients after LT. Its diagnostic performance increased when combined with ALP in a newly developed scoring system.

Sonographic Evaluation of Complications of Liver Transplantation

This article reviews several of the major complications that occur after liver transplantation and describes radiologic modalities used to diagnose and evaluate them. To illustrate the discussion, case presentations of five patients who under-went liver transplantation at the Nazih Zuhdi Transplantation Institute at Integris Baptist Medical Center in Oklahoma City are given. Many of the major complications of liver transplantation can be characterized as vascular or biliary in origin. Hepatic artery thrombosis is the most dreaded complication in the immediate postoperative period because it often necessitates retransplantation. Hepatic artery stenosis can alter graft function as well. Less common arterial complications include pseudoaneurysm formation, hepatic artery rupture and arteriovenous fistula formation. Venous complications include inferior vena cava and portal vein thrombosis and stenosis. Gray-scale and color Doppler ultrasound play a primary role in detection of vascular complications. Angiography or venography may be used for definitive diagnosis. Biliary complications, such as biliary leakage or stricture, occur with some frequency after transplantation and are best evaluated with sonography, cholangiography, and nuclear medicine studies. A late complication of liver transplantation is posttransplant lymphoproliferative disorder, which may be detected and evaluated by ultrasound, computed tomography, and magnetic resonance imaging. Graft rejection is better detected by nonradiologic means.

Radiologic Characterization of Ischemic Cholangiopathy in Donation-After-Cardiac-Death Liver Transplants and Correlation With Clinical Outcomes

OBJECTIVE

The purpose of this study was to define the cholangiographic patterns of ischemic cholangiopathy and clinically silent nonanastomotic biliary strictures in donation-after-cardiac-death (DCD) liver grafts in a large single-institution series. We also examined the correlation of the radiologic findings with laboratory data and clinical outcomes.

MATERIALS AND METHODS

Data were collected for all DCD liver transplants at one institution from December 1998 to December 2011. Posttransplant cholangiograms were obtained during postoperative weeks 1 and 3 and when clinically indicated. Intrahepatic biliary strictures were classified by anatomic distribution and chronologic development. Radiologic findings were correlated with laboratory data and with 1-, 3-, and 5-year graft and patient survival rates.

RESULTS

A total of 231 patients received DCD grafts. Cholangiograms were available for 184 of these patients. Postoperative cholangiographic findings were correlated with clinical data and divided into the following three groups: A, normal cholangiographic findings with normal laboratory values; B, radiologic abnormalities and cholangiopathy according to laboratory values; and C, radiologic abnormalities without laboratory abnormalities. Group B had four distinct abnormal cholangiographic patterns that were predictive of graft survival. Group C had mild nonprogressive multifocal stenoses and decreased graft and patient survival rates, although cholangiopathy was not detected in these patients according to laboratory data.

CONCLUSION

Patterns and severity of nonanastomotic biliary abnormalities in DCD liver transplants can be defined radiologically and correlate with clinical outcomes. Postoperative cholangiography can depict the mild biliary abnormalities that occur in a subclinical manner yet cause a marked decrease in graft and patient survival rates in DCD liver transplants.

Impact of non-anastomotic biliary strictures after liver transplantation on healthcare consumption, use of ionizing radiation and infectious events

BACKGROUND

Non-anastomotic biliary strictures (NAS) after orthotopic liver transplantation (OLT) have a negative influence on graft survival. Expert opinion suggests a negative effect of NAS on other important aspects of post-transplant care, although its impact is largely unknown as data are scarce.

METHODS

This retrospective single center study analyzed data on healthcare consumption, use of ionizing radiation, infectious complications and development of highly resistant microorganisms (HRMO) in adult patients with NAS. A comparison with a matched control group was made.

RESULTS

Forty-three liver recipients with NAS and 43 controls were included. Hospital admissions were higher in patients with NAS. Most common reason for admission was bacterial cholangitis (BC), with 70% of the patients having at least one episode compared to 9% in the control group. In patients with NAS, 67% received at least one ERCP compared to 21% in the control group (p = 0.001). This resulted in a larger yearly received radiation dose for patients with NAS (p = 0.001). Frequency of intravenous antibiotic therapy was higher (p = 0.001) for patients with NAS, consistently resulting in a higher number of cultures found with HRMO (p = 0.012).

CONCLUSION

NAS after OLT have a negative effect on post-transplant care, increasing readmission rates, interventional procedures, exposure to ionizing radiation, use of antibiotics, and development of HRMO.

Molecular hydrogen attenuates hypoxia/reoxygenation injury of intrahepatic cholangiocytes by activating Nrf2 expression

Hypoxia/reoxygenation (H/R) injury of cholangiocytes causes serious biliary complications during hepatobiliary surgeries. Molecular hydrogen (H2) has been shown to be effective in protecting various cells and organs against oxidative stress injury. Human liver cholangiocytes were used to determine the potential protective effects of hydrogen against cholangiocyte H/R injury and explore the underlying mechanisms. We found that H2 ameliorated H/R-induced cholangiocytes apoptosis. Our study revealed that H2 activated NF-E2-related factor 2 (Nrf2) and downstream cytoprotective protein expression. However, the protective function of H2 was abolished when Nrf2 was silenced. Apoptosis in cholangiocytes isolated from a rat model of liver ischemia/reperfusion injury indicated that H2 significantly attenuates ischemia/reperfusion cholangiocyte injury in vivo. In conclusion, our study shows that H2 protects intrahepatic cholangiocytes from hypoxia/reoxygenation-induced apoptosis in vitro or in vivo, and this phenomenon may depend on activating Nrf2 expression.

Spectrum of biliary complications following live donor liver transplantation

Liver transplantation is the optimal treatment for many patients with advanced liver disease, including decompensated cirrhosis, hepatocellular carcinoma and acute liver failure. Organ shortage is the main determinant of death on the waiting list and hence living donor liver transplantation (LDLT) assumes importance. Biliary complications are the most common post operative morbidity after LDLT and occur due to anatomical and technical reasons. They include biliary leaks, strictures and cast formation and occur in the recipient as well as the donor. The types of biliary complications after LDLT along with their etiology, presenting features, diagnosis and endoscopic and surgical management are discussed.

Ex Situ Normothermic Machine Perfusion of Donor Livers

In contrast to conventional static cold preservation (0-4 °C), ex situ machine perfusion may provide better preservation of donor livers. Continuous perfusion of organs provides the opportunity to improve organ quality and allows ex situ viability assessment of donor livers prior to transplantation. This video article provides a step by step protocol for ex situ normothermic machine perfusion (37 °C) of human donor livers using a device that provides a pressure and temperature controlled pulsatile perfusion of the hepatic artery and continuous perfusion of the portal vein. The perfusion fluid is oxygenated by two hollow fiber membrane oxygenators and the temperature can be regulated between 10 °C and 37 °C. During perfusion, the metabolic activity of the liver as well as the degree of injury can be assessed by biochemical analysis of samples taken from the perfusion fluid. Machine perfusion is a very promising tool to increase the number of livers that are suitable for transplantation.

Trps1 regulates biliary epithelial-mesenchymal transition and has roles during biliary fibrosis in liver grafts: a preliminary study

Objective

To investigate the role(s) of Trps1 in non-anastomotic biliary stricture (NABS) following liver transplantation.

Methods

Immunohistochemical and histological techniques were used to detect Trps1, E-cadherin, CK19, vimentin, α-SMA, and collagen deposition. Human intrahepatic biliary epithelial cells (HIBECs) were infected with a Trps1 adenovirus, or transfected with Trps1 short-interfering RNAs (siRNAs). Reverse transcription polymerase chain reaction (RT-PCR) assays and western blotting were used to determine expression levels of epithelial and mesenchymal markers, and Trps1 in HIBECs.

Results

Expression of Trps1 and epithelial markers was down-regulated or absent in NABS liver samples. Mesenchymal markers were seen in biliary epithelial cells (BECs), with collagen deposited around the bile duct. Trps1 expression positively correlated with epithelial markers. Expression of epithelial marker mRNAs and proteins in HIBECs decreased with prolonged cold preservation (CP), while mesenchymal marker expression increased. A 12-h CP period led to increased Trps1 mRNA and protein levels. Expression of E-cadherin was increased in HIBECs following Trps1 adenovirus infection and CP/reperfusion injury (CPRI), with vimentin expression levels reduced and CPRI-mediated epithelial-mesenchymal transition (EMT) inhibited. Transfection of HIBECs with Trps1 siRNAs in conjunction with CPRI revealed that E-cadherin expression was decreased, vimentin expression was increased, and CPRI-mediated EMT was promoted.

Conclusion

Trps1 is involved in NABS pathogenesis following liver transplantation and negatively correlates with BEC EMT and biliary fibrosis in liver grafts. Trps1 demonstrates antagonistic effects that could reverse EMT.

Autophagy and liver ischemia-reperfusion injury

Liver ischemia-reperfusion (I-R) injury occurs during liver resection, liver transplantation, and hemorrhagic shock. The main mode of liver cell death after warm and/or cold liver I-R is necrosis, but other modes of cell death, as apoptosis and autophagy, are also involved. Autophagy is an intracellular self-digesting pathway responsible for removal of long-lived proteins, damaged organelles, and malformed proteins during biosynthesis by lysosomes. Autophagy is found in normal and diseased liver. Although depending on the type of ischemia, warm and/or cold, the dynamic process of liver I-R results mainly in adenosine triphosphate depletion and in production of reactive oxygen species (ROS), leads to both, a local ischemic insult and an acute inflammatory-mediated reperfusion injury, and results finally in cell death. This process can induce liver dysfunction and can increase patient morbidity and mortality after liver surgery and hemorrhagic shock. Whether autophagy protects from or promotes liver injury following warm and/or cold I-R remains to be elucidated. The present review aims to summarize the current knowledge in liver I-R injury focusing on both the beneficial and the detrimental effects of liver autophagy following warm and/or cold liver I-R.

Clinical outcomes and costs associated with in-hospital biliary complications after liver transplantation: a cross-sectional analysis

INTRODUCTION

In-hospital biliary complications (BCs) after liver transplantation (LT) are reported in up to 20 % of patients and contribute to poor outcomes and increased costs. Existing single-center outcome and cost analyses studies are limited in scope.

METHODS

This is a cross-sectional analysis of national data involving 7,967 patients transplanted between 2011 and 2012 with the primary aim of determining the association between BCs and clinical outcomes and costs. Age, race, diagnosis, and severity of illness are associated with the development of BCs.

RESULTS

BCs develop in 14.6 % of LT recipients and have substantial implications for perioperative outcomes, including length of hospital and ICU stay (27.9 vs 19.6 mean days, p < 0.001 and 12.0 vs 8.3 mean days, p < 0.001, respectively), in-hospital morbidity (39 vs 27 %, p < 0.001), 30-day readmissions (14.8 vs 11.2 %, p < 0.001), and in-hospital mortality (5.8 vs 4.0 %, p < 0.001). BCs contributed to a mean increase in in-hospital costs of $36,212 (p < 0.001), due to increases in accommodations ($9,539, p < 0.001), surgical services ($3,988, p < 0.001), and pharmacy services ($8,445, p < 0.001).

DISCUSSION

BCs are a predominant etiology for in-hospital morbidity and mortality, while contributing significantly to the high cost of LT. Efforts should be focused on understanding salient and modifiable risk factors, while developing innovative strategies to reduce BCs.

The bile duct in donation after cardiac death donor liver transplant

PURPOSE OF REVIEW

This review considers the biliary complications associated with liver transplantation using donation after cardiac death (DCD) donor grafts.

RECENT FINDINGS

The increasing use of DCD liver grafts with their increased incidence of biliary complications is discussed. The ethics of this greater use is briefly analysed. Recent animal and human study evidence to support the peribiliary vascular plexus' role in ischaemic cholangiopathy is reviewed. Recent advances in in-vivo and ex-vivo perfusion are explored. In particular, the latest theories regarding perfusion's peribiliary plexus preserving effects and the mechanism by which biliary regeneration may be promoted as a consequence are discussed.

SUMMARY

This article explores the need for DCD liver graft use and the associated biliary complications. The current theories regarding the cause of DCD biliary complications are reviewed, as are the current strategies to reduce them.

Vasculobiliary complications following adult right lobe split liver transplantation from the perspective of reconstruction techniques

Split liver transplantation (SLT) compensates for the organ shortage and provides an alternative solution for recipients disadvantaged by a smaller body size. Variations in the hepatic arterial anatomy and reconstructive techniques may lead to more technical complications, and we sought to analyze the incidence and risk factors of vasculobiliary complications with respect to reconstructive techniques. We identified 171 adult right lobe SLT procedures and 1412 whole liver transplantation (WLT) procedures between January 2000 and June 2012 and compared the results of these 2 groups. In the SLT group, arterial reconstruction techniques were classified into 4 subgroups (I-IV), and biliary reconstruction was classified into 2 groups [duct-to-duct (DD) anastomosis and Roux-en-Y hepaticojejunostomy (RH)]. Specific surgical complications were analyzed against reconstruction techniques. The overall incidence of vascular and biliary complications in the SLT group was greater than that in the WLT group (P = 0.009 and P = 0.001, respectively). There was no difference in hepatic artery thrombosis (HAT), but we saw a tendency toward early HAT in the presence of multiple hepatic arteries supplying the right lobe graft (group IV; 20%) in comparison with the other arterial reconstruction groups (P = 0.052). No difference was noticed in the overall incidence of biliary complications in either DD or RH recipients across 4 arterial reconstruction groups. When the arterial reconstruction involved a right hepatic artery (groups II and III) combined with a DD biliary anastomosis, there was a significant preponderance of biliary complications (P = 0.04 and P = 0.01, respectively). There was no survival difference between SLT and WLT grafts. In conclusion, the complications of SLT are directly related to arterial and biliary reconstruction techniques, and this classification helps to identify high-risk reconstructive techniques.

Risk factors for early and late biliary complications in pediatric liver transplantation

BC are a common source of morbidity after pediatric LT. Knowledge about risk factors may help to reduce their incidence. Retrospective analysis of BC in 116 pediatric patients (123 LT) (single institution, 05/1990-12/2011, medium follow-up 7.9 yr). One-, five-, and 10-yr survival was 91.1%, no patient died of BC. Prevalence and risk factors for anastomotic and intrahepatic BC were examined. There were 29 BC in 123 LT (23.6%), with three main categories: 10 (8.1%) primary anastomotic strictures, eight (6.5%) anastomotic leaks, and three (2.4%) intrahepatic strictures. Significant risk factors for anastomotic leaks were total operation time (increase 1.26-fold) and early HAT (<30 days post-LT; increase 5.87-fold). Risk factor for primary anastomotic stricture was duct-to-duct choledochal anastomosis (increase 5.96-fold when compared to biliary-enteric anastomosis). Risk factors for intrahepatic strictures were donor age >48 yr (increase 1.09-fold) and MELD score >30 (increase 1.2-fold). To avoid morbidity from anastomotic BC in pediatric LT, the preferred biliary anastomosis appears to be biliary-enteric. Operation time should be kept to a minimum, and HAT must by all means be prevented. Children with a high MELD score or receiving livers from older donors are at increased risk for intrahepatic strictures.

Endoscopic retrograde cholangiography for biliary anastomotic strictures after liver transplantation

Biliary complications after liver transplantation (LT) are an important cause of morbidity and mortality. In most cases, an anastomosis of the bile duct is performed as a duct-to-duct reconstruction, which makes endoscopic therapy with endoscopic retrograde cholangiography (ERC) feasible. Biliary anastomotic strictures (AS) are the most common cause of biliary complications. The early detection of an AS, which can sometimes be challenging given that its clinical presentation is often subtle, is of key importance to obtain high treatment success. In this review, we focus on the management of AS after LT with a special emphasis on ERC.