Early-onset versus late-onset nonanastomotic biliary strictures post liver transplantation: risk factors reflect different pathogenesis

Return of the cold: How hypothermic oxygenated machine perfusion is changing liver transplantation

Hypothermic Oxygenated machine PErfusion (HOPE) has recently emerged as a preservation technique which can reduce ischemic injury and improve clinical outcomes following liver transplantation. First developed with the advent solid organ transplantation techniques, hypothermic machine perfusion largely fell out of favour following the development of preservation solutions which can satisfactorily preserve grafts using the cheap and simple method, static cold storage (SCS). However, with an increasing need to develop techniques to reduce graft injury and better utilise marginal and donation after circulatory death (DCD) grafts, HOPE has emerged as a relatively simple and safe technique to optimise clinical outcomes following liver transplantation. Perfusing the graft with cold, acellular, oxygenated perfusate either via the portal vein (PV) alone, or via both the PV and hepatic artery (HA), HOPE is generally commenced for a period of 1-2 h immediately prior to implantation. The technique has been validated by multiple randomised control trials, and pre-clinical evidence suggests HOPE primarily reduces graft injury by decreasing the accumulation of harmful mitochondrial intermediates, and subsequently, the severity of post-reperfusion injury. HOPE can also facilitate real time graft assessment, most notably via the measurement of flavin mononucleotide (FMN) in the perfusate, allowing transplant teams to make better informed clinical decisions prior to transplantation. HOPE may also provide a platform to administer novel therapeutic agents to ex situ organs without risk of systemic side effects. As such, HOPE is uniquely positioned to revolutionise how liver transplantation is approached and facilitate optimised clinical outcomes for liver transplant recipients.

Histological Assessment of the Bile Duct before Liver Transplantation: Does the Bile Duct Injury Score Predict Biliary Strictures?

INTRODUCTION

Histological injury to the biliary tree during organ preservation leads to biliary strictures after liver transplantation. The Bile Duct Injury (BDI) score was developed to assess histological injury and identify the grafts most likely to develop biliary strictures. The BDI score evaluates the bile duct mural stroma, peribiliary vascular plexus (PVP) and deep peribiliary glands (DPGs), which were correlated with post-transplant biliary strictures. However, the BDI score has not been externally validated. The aim of this study was to verify whether the BDI score could predict biliary strictures at our transplant centre.

METHODS

Brain-dead donor liver grafts transplanted at a single institution from March 2015 to June 2016 were included in this analysis. Bile duct biopsies were collected immediately before transplantation and assessed for bile duct injury by two blinded pathologists. The primary outcome was the development of clinically significant biliary strictures within 24 months post-transplant.

RESULTS

Fifty-seven grafts were included in the study which included 16 biliary strictures (28%). Using the BDI score, mural stromal, PVP and DPG injury did not correlate with biliary strictures including Non-Anastomotic Strictures. Severe inflammation (>50 leucocytes per HPF) was the only histological feature inversely correlated with the primary outcome (absent in the biliary stricture group vs. 41% in the no-stricture group, p = 0.001).

CONCLUSIONS

The current study highlights limitations of the histological assessment of bile duct injury. Although all grafts had bile duct injury, only inflammation was associated with biliary strictures. The BDI score was unable to predict post-transplant biliary strictures in our patient population.

Does an Additional Bile Duct Flush With Low-viscosity Preservation Solution Reduce Bile Duct Injury? A Single-blinded Randomized Clinical Trial

Biliary complications are a common cause of morbidity after liver transplantation and associated with bile duct injury. To reduce injury, a bile duct flush is performed with high-viscosity preservation solution. It has been suggested that an earlier additional bile duct flush with low-viscosity preservation solution may reduce bile duct injury and biliary complications. This study aimed to investigate whether an earlier additional bile duct flush would reduce bile duct injury or biliary complications.

Methods

A randomized trial was conducted using 64 liver grafts from brain dead donors. The control group received a bile duct flush with University of Wisconsin (UW) solution after donor hepatectomy. The intervention group received a bile duct flush using low-viscosity Marshall solution immediately after the onset of cold ischemia and a bile duct flush with University of Wisconsin solution after donor hepatectomy. The primary outcomes were the degree of histological bile duct injury, assessed using the bile duct injury score, and biliary complications within 24 mo of transplant.

Results

Bile duct injury scores were not different between the 2 groups. Similar rates of biliary complications occurred in the intervention group (31% [n = 9]) and controls (23% [n = 8]) (P = 0.573). No difference between groups was observed for anastomotic strictures (24% versus 20%, P = 0.766) or nonanastomotic strictures (7% versus 6%, P = 1.00).

Conclusions

This is the first randomized trial to investigate an additional bile duct flush using low-viscosity preservation solution during organ procurement. The findings from this study suggest that performing an earlier additional bile duct flush with Marshall solution does not prevent biliary complications and bile duct injury.

Prognostic Factors for Non-anastomotic Biliary Strictures Following Adult Liver Transplantation: A Systematic Review and Meta-Analysis

INTRODUCTION

The development of non-anastomotic biliary strictures (NAS) following orthotopic adult liver transplantation (OLT) is associated with significant morbidity. We performed a systematic review and meta-analysis to identify all prognostic factors for the development of NAS.

METHODS

A systematic review was conducted following preferred reporting items for systematic reviews and meta-analyses (PRISMA) and the meta-analysis of observational studies in epidemiology (MOOSE) guidelines. We used the Newcastle-Ottawa scale to assess the quality of the included studies. Using the random-effects model, we calculated the weighted pooled odds ratios (OR), mean differences (MD), hazard ratios (HR), and 95% confidence intervals (CI) of the risk factors.

RESULTS

Based on 19 international studies that included a total of 8269 adult LT patients, we calculated an 8% overall incidence of NAS. In this study, 7 potential prognostic factors were associated with a statistically significant hazard ratio for NAS in pooled analyses including (1) DCD donors compared to DBD donors (2) PSC as an indication for a liver transplant (3) Roux-en-Y bile duct reconstruction compared to duct-to-duct reconstruction (4) hepatic artery thrombosis (5) longer cold ischemia time (6) longer warm ischemia time (7) and total operative times.

CONCLUSION

In this systematic review and meta-analysis, we identified 7 prognostic factors for the development of NAS following OLT. These findings might lay the groundwork for development of diagnostic algorithms to better risk stratify patients at risk for development of NAS.

Risk Factors for Development of Biliary Stricture After Liver Transplant in Adult Patients: A Single-Center Retrospective Study

Identification of risk factors for biliary stricture after liver transplant and its potential prevention is crucial to improve the outcomes and reduce the complications. We retrospectively analyzed donor and recipient characteristics with intraoperative and postoperative parameters to identify the risk factors for development of post-transplant anastomotic and nonanastomotic biliary strictures with additional analysis of the time onset of those strictures. A total of 412 patients were included in this study. Mean (SD) follow-up time was 79 (35) months (range, 1-152 months). Biliary stricture was diagnosed in 84 patients (20.4%). Multivariate analysis indicated that postoperative biliary leakage (odd ratio [OR], 3.94; P = .001), acute cellular rejection (OR, 3.05; P < .001), donor age older than 47.5 years (OR, 2.05; P = .032), preoperative recipient platelet value < 77.5 × 10³/mL (OR, 1.91; P = .023), University of Wisconsin solution (OR, 1.73; P = .041)), recipient male sex (OR, 1.78; P = .072), portal/arterial flow ratio > 4 (OR, 1.76; P = .083), and intraoperative bleeding > 2850 mL (OR, 1.70; P = .053) were independent risk factors for biliary stricture regardless of the time of their appearance. Multiple risk factors for biliary stricture were determined in this study. Some of these risk factors are preventable, and implementation of strategies to eliminate some of those factors should reduce the development of post-transplant biliary stricture.

CEUS detection of biliary ischaemia during the first 4 weeks after liver transplantation predicts non-anastomotic biliary stricture

BACKGROUND

Biliary ischaemia is an important factor in the pathogenesis of non-anastomotic biliary stricture (NAS) after liver transplantation (LT). Contrast-enhanced ultrasound (CEUS) can be used to detect biliary ischaemia, but no study has examined the utility of CEUS in predicting NAS.

OBJECTIVE

To evaluate whether repeated CEUS as a non-invasive method of biliary ischaemia can identify NAS.

METHODS

Consecutive LT patients who underwent CEUS examinations at 1-4 weeks after LT from September 2012 to December 2015 at our institution were included. The CEUS images and clinical data were analysed.

RESULTS

Among 116 eligible LT patients, 39 (33.6%) were diagnosed with NAS within 1 year after LT. The patients with NAS had a significantly higher CEUS score at weeks 2-4 (all P <  0.05) and a higher slope of CEUS score progression (0.480 vs -0.044, P <  0.001). The accuracy of CEUS in identifying NAS improved over time after LT, reaching its maximum at week 4, with a sensitivity of 66.7%, a specificity of 87.9%, a positive predictive value (PPV) of 75.9%, a negative predictive value (NPV) of 82.3%, and an accuracy of 80.2%in the full cohort when a CEUS score≥3 was used as the cut-off. Multivariate analysis identified gamma-glutamyl transpeptidase (GGT), alanine transaminase (ALT) and the CEUS score at week 4 as independent predictors of NAS. In the task of identifying NAS, an NAS score combining the above 3 variables at week 4 showed areas under the receiver operating characteristic curve of 0.88 (95%CI, 0.78-0.99) in the estimation group (n = 60) and 0.82 (95%CI, 0.69-0.96) in the validation group (n = 56). An NAS score cut-off of 0.396 identified 87.2%of NAS cases in the estimation group, with a PPV of 93.3%; and 75.0%of NAS cases in the validation group, with a PPV of 58.8%.

CONCLUSIONS

CEUS examination during the first 4 weeks is useful in assessing the risk of NAS within 1 year after LT. In particular, an NAS score combining the CEUS score, GGT level, and ALT level at week 4 can be used to accurately predict the risk of NAS in LT patients.

Association between indocyanine green clearance test and ischemic type biliary lesions within one year after orthotopic liver transplantation

BACKGROUND

Ischemic type biliary lesions (ITBLs), a particular subset of non-anastomotic biliary strictures (NAS), are characterized by intra and extrahepatic strictures that occur in the absence of either hepatic artery thrombosis or stenosis. When they occur within the first year after liver transplantation their development is mostly related to ischemia-reperfusion injury (IRI). The indocyanine green plasma disappearance rate (ICG-PDR) might be able to predict the probability of IRI-induced graft damage after liver transplantation.

OBJECTIVE

Our aim was to evaluate the association between ICG-PDR and the occurrence of ITBLs. Secondly, we searched for evidence of IRI in patients presenting ITBLs.

METHODS

This retrospective single-center observational study assessed a cohort of 60 liver transplant patients. Each patient underwent ICG-PDR on the 1st postoperative day. ITBLs were identified by means of either cholangiography or magnetic resonance imaging evidence of a deformity and narrowing of the biliary tree in the absence of hepatic artery thrombosis/stenosis.

RESULTS

ITBLs were discovered in 10 patients out of 60 liver recipients (16.67%) within one year after transplantation. A low ICG-PDR value was found to be a significant predictive factor for ITBL development, with an OR of 0.87 and a 95% CI of 0.77-0.97. Liver biopsies were performed in 56 patients presenting unexplained abnormal liver function test results. A statistically significant association was found between the development of ITBLs and anatomopathological evidence of IRI.

LIMITATIONS

Retrospective, single-center study.

CONCLUSIONS

The findings from this study show a relationship between low ICG-PDR values on first post-operative-day and the occurrence of ITBLs within 1 year after transplantation.

Predicting the Safe Use of Deceased After Circulatory Death Liver Allografts in Primary Sclerosing Cholangitis

OBJECTIVES

The use of deceased after circulatory death liver allografts in patients with primary sclerosing cholangitis is controversial, given the increased risk of graft complications in patients with primary sclerosing cholangitis. We hypothesized that transplant of deceased after circulatory death livers into recipients with primary sclerosing cholangitis when appropriately selected using the UK deceased after circulatory death scoring system is not associated with increased graft failure and mortality.

MATERIALS AND METHODS

We analyzed 99 229 transplants (between January 2001 and December 2018) from the Organ Procurement and Transplantation Network database. Deceased after circulatory death transplants were stratified by the UK scoring system as low risk or high risk. We identified 3958 patients with primary sclerosing cholangitis who received deceased after brain death transplant and 95 patients with primary sclerosing cholangitis who received deceased after circulatory death transplant.

RESULTS

As expected, 5-year graft survival was lower in the circulatory death recipient group (69.0% vs 78.4%; P = .02). However, 5-year graft survival was significantly lower in the high-risk versus low-risk UK scoring system group (60.0% vs 75.4%; P = .02), with rate in the low-risk group similar to the brain death recipient group (78.4% vs 75.4%; P = .52). On multivariate analysis, the high-risk group had significantly increased risk of graft loss (hazard ratio of 1.92; P = .01). However, the low-risk group had equivalent graft survival to the brain death recipient group (hazard ratio of 1.23; P = .31).

CONCLUSIONS

Graft failure was higher in patients with primary sclerosing cholangitis who received livers from deceased after circulatory death donors; however, the risk of graft loss was abrogated using appropriately matched donor and recipient combinations.

Biliary Complication in Pediatric Liver Transplantation: a Single-Center 15-Year Experience

BACKGROUND

The incidence and several risk factors of biliary complication (BC) following pediatric liver transplantation (LT) are widely known, but data on long-term outcomes and management is limited. This retrospective study aimed to investigate the incidence, associated risk factors, management, and outcomes of early and late BC in pediatric LT.

METHODS

This study enrolled 134 pediatric patients (< 18 years old) who underwent LT at a tertiary care center in Taiwan between January 2001 and December 2015. Diagnosis of BC was based on clinical, biochemical, and radiologic examinations. Clinical data and chart records were reviewed and compared between the groups.

RESULTS

Among the 134 children, 21 children (15.7%) had BC after LT. Nine children had early complications, including leakage plus stricture (n = 2), stricture only (n = 2), and leakage only (n = 5). Twelve children had late BC; all of whom had anastomotic stricture. Of the 21 patients with BC, 11 patients (52.4%) were treated without surgery. The median time of first treatment for BC was 6.5 months (range, 11 days to 6.2 years). Five of the 9 patients with early complications and two of the 12 patients with late complications died of biliary tract infection. The major risk factors of BC in pediatric LT were (1) recipient age > 2 years, (2) Kasai portoenterostomy revision, and (3) hepatic artery thrombosis.

CONCLUSIONS

Several risk factors of BC in pediatric LT were identified. Children with early BC appeared to have relatively unfavorable outcomes. However, late BC treated by either radiological or surgical methods appeared to have a relatively good long-term prognosis.

Ischemic-type biliary lesions: A leading indication of liver retransplantation with excellent results

BACKGROUND

Liver retransplantation (RLT) is the only life-saving treatment option for patients with a failing graft, but it remains a major challenge because of inferior outcomes and technical difficulties.

METHODS

This study aimed to evaluate the outcomes of and risk factors for adult RLT in a single center, focusing on the etiology of graft failure. Between 1987 and 2011, 1592 liver transplants (LTs) and 143 RLTs (9%) were performed at our institution.

RESULTS

The 1-, 5- and 10-year patient survival rates after RLT were 60%, 52% and 39%, and the graft survival rates were 55%, 46% and 32%. The 90-day mortality rate was 32%, mainly due to septic complications (45% of deaths). Ischemic-type biliary lesions (ITBL) were the leading indication for RLT (23%), and patient survival was significantly better in patients retransplanted for ITBL than for any other indication (P<0.02). Indications other than ITBL (P=0.015), the transfusion of more than 7 units (P=0.006) and preoperative dialysis (P=0.005) were the three parameters associated with poor survival after RLT.

CONCLUSION

Patients with ITBL benefit the most from elective RLT.

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.

Liver grafts procured from donors after circulatory death have no increased risk of microthrombi formation

Microthrombi formation provoked by warm ischemia and vascular stasis is thought to increase the risk of nonanastomotic strictures (NAS) in liver grafts obtained by donation after circulatory death (DCD). Therefore, potentially harmful intraoperative thrombolytic therapy has been suggested as a preventive strategy against NAS. Here, we investigated whether there is histological evidence of microthrombi formation during graft preservation or directly after reperfusion in DCD livers and the development of NAS. Liver biopsies collected at different time points during graft preservation and after reperfusion were triple-stained with hematoxylin-eosin (H & E), von Willebrand factor VIII (VWF), and Fibrin Lendrum (FL) to evaluate the presence of microthrombi. In a first series of 282 sections obtained from multiple liver segments of discarded DCD grafts, microthrombi were only present in 1%-3% of the VWF stainings, without evidence of thrombus formation in paired H & E and FL stainings. Additionally, analysis of 132 sections obtained from matched, transplanted donation after brain death and DCD grafts showed no difference in microthrombi formation (11.3% versus 3.3% respectively; P = 0.082), and no relation to the development of NAS (P = 0.73). Furthermore, no microthrombi were present in perioperative biopsies in recipients who developed early hepatic artery thrombosis. Finally, the presence of microthrombi did not differ before or after additional flushing of the graft with preservation solution. In conclusion, the results of our study derogate from the hypothesis that DCD livers have an increased tendency to form microthrombi. It weakens the explanation that microthrombi formation is a main causal factor in the development of NAS in DCD and that recipients could benefit from intraoperative thrombolytic therapy to prevent NAS following liver transplantation. Liver Transplantation 22 1676-1687 2016 AASLD.

Biliary complications in right lobe living donor liver transplantation

Living donor liver transplantation is an alternative to deceased donor liver transplantation in the face of insufficient deceased donor liver grafts. Unfortunately, the incidence of biliary complication after living donor liver transplantation is significantly higher than that after deceased donor liver transplantation using grafts from non-cardiac-death donations. The two most common biliary complications after living donor liver transplantation are bile leakage and biliary anastomotic stricture. Early treatment with endoscopic and interventional radiological approaches can achieve satisfactory outcomes. If treatment with these approaches fails, the salvage measure for prompt rectification will be surgical revision, which is now seldom performed. This paper also discusses risk factors in donor biliary anatomy that can affect recipients.

The increasing burden of potentially preventable liver disease among adult liver transplant recipients: A comparative analysis of liver transplant indication by era in Australia and New Zealand

BACKGROUND

Hepatitis C (HCV), hepatitis B (HBV), alcohol-related liver disease (ALD), and non-alcohol-related fatty liver disease (NAFLD) are leading indications for adult liver transplantation in Australia and New Zealand. However, these diseases are potentially preventable through effective primary and/or secondary prevention strategies. This study evaluates the relative contribution of potentially preventable liver diseases to liver transplant numbers in Australia and New Zealand over time.

METHODS

Prospectively recorded clinical, demographic, and outcome data were collected from the Australian and New Zealand Liver Transplant Registry for all primary adult liver transplants performed in Australia and New Zealand from 1 January 1985 until 31 December 2012. Potentially preventable liver disease was defined as HBV, HCV, NAFLD, ALD, and HCC. The etiology of liver disease leading to liver transplantation and the proportion of preventable liver disease-related liver transplantation was compared between Era 1 (1985-1993), Era 2 (1994-2003), and Era 3 (2004-2012).

RESULTS

Overall, 1252 of 3266 adult primary liver transplants (38.3%) were performed for potentially preventable liver disease. There was a significant increase in the proportion of liver transplants because of preventable liver disease from 21.2% (93 of 439) in Era 1, to 49.8% (623 of 1252) in Era 2 and 63.5% (1000 of 1575) in Era 3 (P < 0.0001). Over time, there was a significant increase in HCV (P < 0.0001), ALD (P = 0.002), and NAFLD (P < 0.0001) as a primary indication for adult liver transplant, whereas HBV has significantly decreased from Era 1 to Era 3 as an indication for transplant (P < 0.0001). The number of transplants performed for HCC also increased across Eras (P < 0.0001), with 84% due to underlying potentially preventable liver disease.

CONCLUSION

Since 2004, the majority of primary adult liver transplants within Australia and New Zealand have been because of potentially preventable liver diseases and the prevalence of these diseases has increased over time. This finding represents an opportunity for clinicians to make a significant impact on the overall burden of advanced liver disease in Australia and New Zealand by improving primary and secondary prevention measures.

Biliary strictures and recurrence after liver transplantation for primary sclerosing cholangitis: A retrospective multicenter analysis

Liver transplantation (LT) is the only definitive treatment for patients with end-stage liver disease due to primary sclerosing cholangitis (PSC), but a high rate of biliary strictures (BSs) and of recurrent primary sclerosing cholangitis (recPSC) has been reported. In this multicenter study, we analyzed a large patient cohort with a long follow-up in order to evaluate the incidence of BS and recPSC, to assess the impact on survival after LT, and to identify risk factors. We collected clinical, surgical, and laboratory data and records on inflammatory bowel disease (IBD), immunosuppression, recipient and graft outcome, and biliary complications (based on cholangiography and histology) of all patients who underwent LT for PSC in 10 German transplant centers between January 1990 and December 2006; 335 patients (68.4% men; mean age, 38.9 years; 73.5% with IBD) underwent transplantation 8.8 years after PSC diagnosis with follow-up for 98.8 months. The 1-, 5-, and 10-year recipient and graft survival was 90.7%, 84.8%, 79.4% and 79.1%, 69.0%, 62.4%, respectively. BS was diagnosed in 36.1% after a mean time of 3.9 years, and recPSC was diagnosed in 20.3% after 4.6 years. Both entities had a significant impact on longterm graft and recipient survival. Independent risk factors for BS were donor age, ulcerative colitis, chronic ductopenic rejection, bilirubin, and international normalized ratio (INR) at LT. Independent risk factors for recPSC were donor age, IBD, and INR at LT. These variables were able to categorize patients into risk groups for BS and recPSC. In conclusion, BS and recPSC affect longterm graft and patient survival after LT for PSC. Donor age, IBD, and INR at LT are independent risk factors for BS and recPSC and allow for risk estimation depending on the recipient-donor constellation.

Biliary complications in liver transplantation: Impact of anastomotic technique and ischemic time on short- and long-term outcome

AIM: To elucidate the impact of various donor recipient and transplant factors on the development of biliary complications after liver transplantation.

METHODS: We retrospectively reviewed 200 patients of our newly established liver transplantation (LT) program, who received full size liver graft. Biliary reconstruction was performed by side-to-side (SS), end-to-end (EE) anastomosis or hepeaticojejunostomy (HJ). Biliary complications (BC), anastomotic stenosis, bile leak, papillary stenosis, biliary drain complication, ischemic type biliary lesion (ITBL) were evaluated by studying patient records, corresponding radiologic imaging and reports of interventional procedures [e.g., endoscopic retrograde cholangiopancreatography (ERCP)]. Laboratory results included alanine aminotransferase (ALT), gammaglutamyltransferase and direct/indirect bilirubin with focus on the first and fifth postoperative day, six weeks after LT. The routinely employed external bile drain was examined by a routine cholangiography on the fifth postoperative day and six weeks after transplantation as a standard procedure, but also whenever clinically indicated. If necessary, interventional (e.g., ERCP) or surgical therapy was performed. In case of biliary complication, patients were selected, assigned to different complication-groups and subsequently reviewed in detail. To evaluate the patients outcome, we focussed on appearance of postoperative/post-interventional cholangitis, need for rehospitalisation, retransplantation, ITBL or death caused by BC.

RESULTS: A total of 200 patients [age: 56 (19-72), alcoholic cirrhosis: n = 64 (32%), hepatocellular carcinoma: n = 40 (20%), acute liver failure: n = 23 (11.5%), cryptogenic cirrhosis: n = 22 (11%), hepatitis B virus /hepatitis C virus cirrhosis: n = 13 (6.5%), primary sclerosing cholangitis: n = 13 (6.5%), others: n = 25 (12.5%) were included. The median follow-up was 27 mo until June 2015. The overall biliary complication rate was 37.5% (n = 75) with anastomotic strictures (AS): n = 38 (19%), bile leak (BL): n = 12 (6%), biliary drain complication: n = 12 (6%); papillary stenosis (PS): n = 7 (3.5%), ITBL: n = 6 (3%). Clinically relevant were only 19% (n = 38). We established a comprehensive classification for AS with four grades according to clinical relevance. The reconstruction techniques [SS: n = 164, EE: n = 18, HJ: n = 18] showed no significant impact on the development of BCs in general (all n < 0.05), whereas in the HJ group significantly less AS were found (P = 0.031). The length of donor intensive care unit stay over 6 d had a significant influence on BC development (P = 0.007, HR = 2.85; 95%CI: 1.33-6.08) in the binary logistic regression model, whereas other reviewed variables had not [warm ischemic time > 45 min (P = 0.543), cold ischemic time > 10 h (P = 0.114), ALT init > 1500 U/L (P = 0.631), bilirubin init > 5 mg/dL (P = 0.595), donor age > 65 (P = 0.244), donor sex (P = 0.068), rescue organ (P = 0.971)]. 13% (n = 10) of BCs had no therapeutic consequences, 36% (n = 27) resulted in repeated lab control, 40% (n = 30) received ERCP and 11% (n = 8) surgical therapy. Fifteen (7.5%) patients developed cholangitis [AS (n = 6), ITBL (n = 5), PS (n = 3), biliary lesion BL (n = 1)]. One patient developed ITBL twelve months after LT and subsequently needed retransplantation. Rehospitalisation rate was 10.5 % (n= 21) [AS (n = 11), ITBL (n = 5), PS (n = 3), BL (n = 1)] with intervention or reinterventional therapy as main reasons. Retransplantation was performed in 5 (2.5%) patients [ITBL (n = 1), acute liver injury (ALI) by organ rejection (n = 3), ALI by occlusion of hepatic artery (n = 1)]. In total 21 (10.5%) patients died within the follow-up period. Out of these, one patient with AS developed severe fatal chologenic sepsis after ERCP.

CONCLUSION: In our data biliary reconstruction technique and ischemic times seem to have little impact on the development of BCs.

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.

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.

Delayed rearterialization unlikely leads to nonanastomotic stricture but causes temporary injury on bile duct after liver transplantation

Nonanastomotic strictures (NAS) are common biliary complications after liver transplantation (LT). Delayed rearterialization induces biliary injury in several hours. However, whether this injury can be prolonged remains unknown. The correlation of this injury with NAS occurrence remains obscure. Different delayed rearterialization times were compared using a porcine LT model. Morphological and functional changes in bile canaliculus were evaluated by transmission electron microscopy and real-time PCR. Immunohistochemistry and TUNEL were performed to validate intrahepatic bile duct injury. Three months after LT was performed, biliary duct stricture was determined by cholangiography; the tissue of common bile duct was detected by real-time PCR. Bile canaliculi were impaired in early postoperative stage and then exacerbated as delayed rearterialization time was prolonged. Nevertheless, damaged bile canaliculi could fully recover in subsequent months. TNF-α and TGF-β expressions and apoptosis cell ratio increased in the intrahepatic bile duct only during early postoperative period in a time-dependent manner. No abnormality was observed by cholangiography and common bile duct examination after 3 months. Delayed rearterialization caused temporary injury to bile canaliculi and intrahepatic bile duct in a time-dependent manner. Injury could be fully treated in succeeding months. Solo delayed rearterialization cannot induce NAS after LT.

Biliary complications after orthotopic liver transplantation

PURPOSE OF REVIEW

The incidence, pathogenesis and management of the most common biliary complications are summarized, with an emphasis on nonanastomotic biliary strictures (NAS) and potential strategies to prevent NAS after liver transplantation.

RECENT FINDINGS

NAS have variable presentations in time and localization, suggesting various underlying pathogeneses. Early-onset NAS (presentation within 1 year) have shown to be largely related to ischemia-induced bile duct injury, whereas late-onset NAS [>1 year after orthotopic liver transplantation (OLT)] have more immune-mediated causes. Cytotoxic hydrophobic bile salts and impaired biliary HCO3 secretion may also play a role in the occurrence of NAS. Recently, insufficient biliary epithelial regeneration capacity after transplantation has also been suggested to play a major role in the pathogenesis of NAS. A potential strategy to prevent NAS has been proposed to be preservation by machine perfusion instead of classical static cold storage. Although machine perfusion has been shown to be a better preservation method for the liver parenchyma, efficacy in preventing ischemic injury of the biliary epithelium is largely unknown.

SUMMARY

The potential advantages of machine perfusion are very promising as it may provide better protection of the vulnerable bile ducts against ischemia-reperfusion injury. Clinical trials will be needed to demonstrate the impact of machine perfusion in reducing the incidence of biliary complications, especially NAS, after OLT.

MicroRNA profiles in graft preservation solution are predictive of ischemic-type biliary lesions after liver transplantation

BACKGROUND & AIMS

Ischemic-type biliary lesions (ITBL) are the second most common cause of graft loss after liver transplantation. Though the exact pathophysiology of ITBL is unknown, bile duct injury during graft preservation is considered to be a major cause. Here we investigated whether the release of cholangiocyte-derived microRNAs (CDmiRs) during graft preservation is predictive of the development of ITBL after liver transplantation.

METHODS

Graft preservation solutions (perfusates) and paired liver biopsies collected at the end of cold ischemia were analysed by RT-qPCR for CDmiR-30e, CDmiR-222, and CDmiR-296 and hepatocyte-derived miRNAs (HDmiRs) HDmiR-122 and HDmiR-148a. MicroRNAs in perfusates were evaluated on their stability by incubation and fractionation experiments. MicroRNA profiles in perfusates from grafts that developed ITBL (n=20) and grafts without biliary strictures (n=37) were compared.

RESULTS

MicroRNAs in perfusates were proven to be stable and protected against degradation by interacting proteins. Ratios between HDmiRs/CDmiRs were significantly higher in perfusates obtained from grafts that developed ITBL (p<0.01) and were identified as an independent risk factor by multivariate analysis (p<0.01, HR: 6.89). The discriminative power of HDmiRs/CDmiRs in perfusates was validated by analysis of separate brain death- (DBD) and cardiac death donors (DBD; p ≤ 0.016) and was superior to expression in liver biopsies (C=0.77 in perfusates vs. C<0.50 in biopsies).

CONCLUSIONS

This study demonstrates that differential release of CDmiRs during graft preservation is predictive of the development of ITBL after liver transplantation. This provides new evidence for the link between graft-related bile duct injury and the risk for later development of ITBL.

Establishment of a rat liver transplantation model with prolonged biliary warm ischemia time

AIM: To investigate the impact of different time points of secondary warm ischemia on bile duct in a rat autologous liver transplantation model with external bile drainage.

METHODS: One hundred and thirty-six male inbred SD rats were randomly assigned to one of four groups (I-IV) according to the secondary warm ischemia time of 0, 10, 20 and 40 min. A rat model of autologous liver transplantation with continuous external biliary drainage under ether anesthesia was established. Ten rats in each group were used to evaluate the one-week survival rate. At 6 h, 24 h, 3 d and 7 d after reperfusion of the hepatic artery, 6 rats were killed in each group to collect the blood sample via the infrahepatic vena cava and the median lobe of liver for assay. Warm ischemia time of liver, cold perfusion time, anhepatic phase, operative duration for biliary external drainage and survival rates in the four groups were analyzed for the establishment of models.

RESULTS: No significant difference was shown in warm ischemia time, anhepatic phase and operative duration for biliary external drainage among the four groups. Five of the 40 rats in this study evaluated for the one-week survival rate died, including three deaths of severe pulmonary infection in group IV. A significant decrease of one-week survival rate in group IV was noted compared with the other three groups. With the prolongation of the biliary warm ischemia time, the indexes of the liver function assessment were significantly elevated, and biliary epithelial cell apoptosis index also increased. Pathological examinations showed significantly aggravated inflammation in the portal area and bile duct epithelial cell injury with the prolonged secondary warm ischemia time. Microthrombi were found in the micrangium around the biliary tract in some sections from groups III and IV.

CONCLUSION: The relationship between secondary warm ischemia time and the bile duct injury degree is time-dependent, and 20 min of secondary warm ischemia time is feasible for the study of bile duct injury.

Effects of warm ischemia time on biliary injury in rat liver transplantation

AIM: To investigate the effect of different secondary warm ischemia time (SWIT) on bile duct injury in liver-transplanted rats.

METHODS: Forty-eight male inbred Sprague-Dawley rats were randomly assigned into four groups: a sham-operation group and three groups with secondary biliary warm ischemia time of 0 min, 10 min and 20 min. A rat model of autologous liver transplantation under ether anesthesia was established, and six rats were killed in each group and blood samples and the median lobe of the liver were collected for assay at 6 h and 24 h after hepatic arterial reperfusion.

RESULTS: With prolongation of biliary warm ischemia time, the level of vascular endothelial growth factor-A was significantly decreased, and the value at 24 h was higher than that at 6 h after hepatic arterial reperfusion, but with no significant difference. The extended biliary SWIT led to a significant increase in bile duct epithelial cell apoptosis, and a decrease in the number of blood vessels, the bile duct surrounding the blood vessels and bile duct epithelial cell proliferation in the early postoperative portal area. Pathologic examinations showed that inflammation of the rat portal area was aggravated, and biliary epithelial cell injury was significantly worsened.

CONCLUSION: A prolonged biliary warm ischemia time results in aggravated injury of the bile duct and the surrounding vascular plexus in rat autologous orthotopic liver transplantation.