Biliary complications after liver transplantation: Assessment with MR cholangiopancreatography and MR imaging at 3T device

Imaging of Ischemic Cholangiopathy Following Donation after Circulatory Death Liver Transplant

Ischemic cholangiopathy (IC) is the leading cause of inferior long-term outcomes following donation after circulatory death (DCD) liver transplant. Biliary strictures related to IC are nonanastomotic strictures (NASs) by definition and involve the donor hepatic ducts proximal to the anastomosis, compared with postsurgical anastomotic strictures that form due to fibrotic healing. IC-related NASs can be microangiopathic with patent hepatic artery or macroangiopathic with occluded or stenotic hepatic artery. Recently, IC with NASs have been described to have four distinct patterns at imaging: diffuse necrosis, multifocal progressive, confluence dominant, and minor form, which correlate clinically with graft prognosis. Severe IC can lead to ductal wall breakdown with subsequent bile leaks that can cause significant patient morbidity, with imaging playing a vital role in diagnosis and guiding intervention. IC also predisposes the transplanted liver to biliary stasis and subsequent formation of stones, casts, and sludge. Some cases of posttransplant biliary stricturing are not IC but are a sequela of reflux cholangitis seen with choledochojejunal anastomosis. Other biliary findings in the posttransplant liver can be explained by sphincter of Oddi dysfunction that results from denervation. The authors describe and comprehensively categorize the various IC types and their imaging patterns at MRI and MR cholangiopancreatography, review the prognostic significance of these imaging patterns, and discuss imaging features of additional biliary complications associated with IC after DCD liver transplant. ©RSNA, 2024 Supplemental material is available for this article.

Sequential Normothermic Regional Perfusion and End-ischemic Ex Situ Machine Perfusion Allow the Safe Use of Very Old DCD Donors in Liver Transplantation

BACKGROUND

In Italy, 20 min of continuous, flat-line electrocardiogram are required for death declaration. Despite prolonged warm ischemia time, Italian centers reported good outcomes in controlled donation after circulatory death (cDCD) liver transplantation by combining normothermic regional and end-ischemic machine perfusion (MP). The aim of this study was to evaluate the safety and feasibility of the use of septuagenarian and octogenarian cDCD donors with this approach.

METHODS

All cDCD older than 70 y were evaluated during normothermic regional perfusion and then randomly assigned to dual hypothermic or normothermic MP.

RESULTS

In the period from April 2021 to December 2022, 17 cDCD older than 70 y were considered. In 6 cases (35%), the graft was not considered suitable for liver transplantation, whereas 11 (65%) were evaluated and eventually transplanted. The median donor age was 82 y, being 8 (73%) older than 80. Median functional warm ischemia and no-flow time were 36 and 28 min, respectively. Grafts were randomly assigned to ex situ dual hypothermic oxygenated MP in 6 cases (55%) and normothermic MP in 5 (45%). None was discarded during MP. There were no cases of primary nonfunction, 1 case of postreperfusion syndrome (9%) and 2 cases (18%) of early allograft dysfunction. At a median follow-up of 8 mo, no vascular complications or ischemic cholangiopathy were reported. No major differences were found in terms of postoperative hospitalization or complications based on the type of MP.

CONCLUSIONS

The implementation of sequential normothermic regional and end-ischemic MP allows the safe use of very old donation after circulatory death donors.

An extensive evaluation of hepatic markers of damage and regeneration in controlled and uncontrolled donation after circulatory death

Livers from donations after circulatory death (DCDs) are very sensitive to ischemia/reperfusion injury and thus need careful reconditioning, such as normothermic regional perfusion (NRP). So far, its impact on DCDs has not been thoroughly investigated. This pilot cohort study aimed to explore the NRP impact on liver function by evaluating dynamic changes of circulating markers and hepatic gene expression in 9 uncontrolled DCDs (uDCDs) and 10 controlled DCDs. At NRP start, controlled DCDs had lower plasma levels of inflammatory and liver damage markers, including α-glutathione s-transferase, sorbitol-dehydrogenase, malate dehydrogenase 1, liver-type arginase-1, and keratin-18, but higher levels of osteopontin, sFas, flavin mononucleotide, and succinate than uDCDs. During 4-hour NRP, some damage and inflammatory markers increased in both groups, while IL-6, HGF, and osteopontin increased only in uDCDs. At the NRP end, the tissue expression of early transcriptional regulators, apoptosis, and autophagy mediators was higher in uDCDs than in controlled DCDs. In conclusion, despite initial differences in liver damage biomarkers, the uDCD group was characterized by a major gene expression of regenerative and repair factors after the NRP procedure. Correlative analysis among circulating/tissue biomarkers and the tissue congestion/necrosis degree revealed new potential candidate biomarkers.

Biliary complications after liver transplantation: A computed tomography and magnetic resonance imaging pictorial review

Biliary complications are the most common complications after liver transplantation. Computed tomography (CT) and magnetic resonance imaging (MRI) are cornerstones for timely diagnosis of biliary complications after liver transplantation. The diagnosis of these complications by CT and MRI requires expertise, mainly with respect to identifying subtle early signs to avoid missed or incorrect diagnoses. For example, biliary strictures may be misdiagnosed on MRI due to size mismatch of the common ducts of the donor and recipient, postoperative edema, pneumobilia, or susceptibility artifacts caused by surgical clips. Proper and prompt diagnosis of biliary complications after transplantation allows the timely initiation of appropriate management. The aim of this pictorial review is to illustrate various CT and MRI findings related to biliary complications after liver transplantation, based on time of presentation after surgery and frequency of occurrence.

The role of sequential normothermic regional perfusion and end-ischemic normothermic machine perfusion in liver transplantation from very extended uncontrolled donation after cardiocirculatory death

The use of pre-procurement normothermic regional perfusion (NRP) allowed us to implement controlled DCD liver transplantation with results comparable to brain death donors, but the use of uncontrolled DCD is declining due to logistic challenges and the high incidence of post-transplant complications. In Italy, the mandatory stand-off period of 20 min for DCD donors has driven the combined use of NRP and ex-situ machine perfusion with the intent to counterbalance the negative impact of prolonged warm ischemia. Organ viability during NRP is based on duration of warm ischemia, regional perfusion flow, lactate, transaminases values and histology, and those used in Italy are the widest worldwide. However, this evaluation can be difficult, especially when the acute damage is particularly severe. The use of ex-situ NRP could provide a safe organ evaluation. In the period from 06/2020 to 06/2022, all DCD grafts exceeding NRP viability criteria at a single center were eventually evaluated using ex-situ normothermic machine perfusion. Machine perfusion viability criteria were based on lactate clearance, irrespectively to bile production, unless 1-h transaminases perfusate level were not exceeding 5000 IU/L. Three cases of uncontrolled DCD grafts in excess of NRP viability criteria underwent ex-situ graft evaluation. Two matched ex-situ normothermic machine perfusion viability criteria and were successfully transplanted. Both recipients are doing well after 26 and 5 months after surgery with no signs of ischemic cholangiopathy. This experience suggests that the sequential use of NRP and normothermic machine perfusion may further expand the boundaries of organ viability in uncontrolled DCD liver transplantation.

Radiologic findings of biliary complications post liver transplantation

Liver transplantation is a potentially curative treatment for patients with acute liver failure, end-stage liver disease, and primary hepatic malignancy. Despite tremendous advancements in surgical techniques and immunosuppressive management, there remains a high rate of post-transplant complications, with one of the main complications being biliary complications. In addition to anastomotic leak and stricture, numerous additional biliary complications are encountered, including ischemic cholangiopathy due to the sole arterial supply of the bile ducts, recurrence of primary biliary disease, infections, biliary obstruction from stones, cast, or hemobilia, and less commonly cystic duct remnant mucocele, vanishing duct syndrome, duct discrepancy and kinking, post-transplant lymphoproliferative disorder, retained stent, and ampullary dysfunction. This article presents an overview of biliary anatomy and surgical techniques in liver transplantation, followed by a detailed review of post-transplant biliary complications with their corresponding imaging findings on multiple modalities with emphasis on magnetic resonance imaging and MR cholangiopancreatography.

Viability Criteria during Liver Ex-Situ Normothermic and Hypothermic Perfusion

With the increased use of extended-criteria donors, machine perfusion became a beneficial alternative to cold storage in preservation strategy for donor livers with the intent to expand donor pool. Both normothermic and hypothermic approach achieved good results in terms of mid- and long-term outcome in liver transplantation. Many markers and molecules have been proposed for the assessment of liver, but no definitive criteria for graft viability have been validated in large clinical trials and key parameters during perfusion still require optimization.In this review, we address the current literature of viability criteria during normothermic and hypothermic machine perfusion and discuss about future steps and evolution of these technologies.

Artificial Intelligence Algorithm-Based CTA Imaging for Diagnosing Ischemic Type Biliary Lesions after Orthotopic Liver Transplantation

The study focused on the clinical application value of artificial intelligence-based computed tomography angiography (CTA) in the diagnosis of orthotopic liver transplantation (OLT) after ischemic type biliary lesions (ITBL). A total of 66 patients receiving OLT in hospital were selected. Convolutional neural network (CNN) algorithm was used to denoise and detect the edges of CTA images of patients. At the same time, the quality of the processed image was subjectively evaluated and quantified by Hmax, Ur, Cr, and other indicators. Then, the digital subtraction angiography (DSA) diagnosis and CTA diagnosis based on CNN were compared for the sensitivity, specificity, positive predictive value, negative predictive value, and patient classification results. It was found that CTA can clearly reflect the information of hepatic aorta lesions and thrombosis in patients with ischemic single-duct injury after liver transplantation. After neural network algorithm processing, the image quality is obviously improved, the lesions are more prominent, and the details of lesion parts are also well displayed. ITBL occurred in 40 (71%) of 56 patients with abnormal CTA at early stage. ITBL occurred in only 8 (12.3%) of 65 patients with normal CTA at early stage. Early CTA manifestations had high sensitivity (72.22%), specificity (87.44%), positive predictive value (60.94%), and negative predictive value (92.06%) for the diagnosis of ITBL. It was concluded that artificial intelligence-based CTA had high clinical application value in the diagnosis of ITBL after OLT.

Biliary complications in recipients of living donor liver transplantation: A single-centre study

BACKGROUND

Biliary complications (BCs) after liver transplantation (LT) remain a considerable cause of morbidity, mortality, increased cost, and graft loss.

AIM

To investigate the impact of BCs on chronic graft rejection, graft failure and mortality.

METHODS

From 2011 to 2016, 215 adult recipients underwent right-lobe living-donor liver transplantation (RT-LDLT) at our centre. We excluded 46 recipients who met the exclusion criteria, and 169 recipients were included in the final analysis. Donors' and recipients' demographic data, clinical data, operative details and postoperative course information were collected. We also reviewed the management and outcomes of BCs. Recipients were followed for at least 12 mo post-LT until December 2017 or graft or patient loss.

RESULTS

The overall incidence rate of BCs including biliary leakage, biliary infection and biliary stricture was 57.4%. Twenty-seven (16%) patients experienced chronic graft rejection. Graft failure developed in 20 (11.8%) patients. A total of 28 (16.6%) deaths occurred during follow-up. BCs were a risk factor for the occurrence of chronic graft rejection and failure; however, mortality was determined by recurrent hepatitis C virus infection.

CONCLUSION

Biliary complications after RT-LDLT represent an independent risk factor for chronic graft rejection and graft failure; nonetheless, effective management of these complications can improve patient and graft survival.

Serum bile acid levels assist the prediction of biliary stricture and survival after liver transplantation in children

Biliary stricture is an important biliary complication after liver transplant in children. We aimed to investigate the utility of serum bile acid levels for prediction of biliary stricture in children after liver transplant. This study enrolled 60 children who underwent liver transplantation at a mean age of 2.04±0.30 years; serum bile acid levels were surveyed in a cross-sectional design. These patients were followed regularly at our institute, and the clinical data were collected prospectively. The major indication of liver transplant in this pediatric cohort was biliary atresia (78.33%). During the follow-up period (3.08±0.30 years), nine patients (15%) developed biliary stricture after the check of serum bile acid. A receiver operating characteristic curve analysis yielded a serum bile acid cutoff of >40 μM for the prediction of biliary stricture (P = 0.002). A serum bile acid level >40 is the most important predictor of a biliary stricture after liver transplant (odds ratio=65.65, P = 0.003) after adjusting for gender and GGT levels. The phenomenon remained on Cox's proportional hazard survival analysis (hazard ratio =15.42, P = 0.001). The mortality risk after liver transplant was significantly higher in subjects with serum bile acid levels >40 μM than in those with levels ≤40 μM (log-rank test, P = 0.004).Conclusion: Serum bile acid levels can be used for non-invasive screening and prediction of biliary stricture and mortality in children after liver transplantation. What is Known: • Biliary stricture is a major biliary complication after pediatric liver transplantation, and we showed the serum bile acid level significantly associates with biliary stricture. What is New: • In this study, we demonstrated the serum bile acid level may assist in the early detection of biliary stricture and mortality non-invasively.

Magnetic Resonance Imaging of Liver Transplant

MR imaging increasingly has been adopted for follow-up imaging post-liver transplantation and for diagnosis of its complications. These include vascular and biliary complications as well as post-transplant malignancies. Interpretation of postoperative MR imaging should take into account the surgical technique and expected post-transplant changes. Contrast-enhanced MR imaging has high sensitivity for identification of vascular complications. MR cholangiopancreatography on the other hand is the most accurate noninvasive method for evaluation of biliary complications.

2020 WSES guidelines for the detection and management of bile duct injury during cholecystectomy

Bile duct injury (BDI) is a dangerous complication of cholecystectomy, with significant postoperative sequelae for the patient in terms of morbidity, mortality, and long-term quality of life. BDIs have an estimated incidence of 0.4-1.5%, but considering the number of cholecystectomies performed worldwide, mostly by laparoscopy, surgeons must be prepared to manage this surgical challenge. Most BDIs are recognized either during the procedure or in the immediate postoperative period. However, some BDIs may be discovered later during the postoperative period, and this may translate to delayed or inappropriate treatments. Providing a specific diagnosis and a precise description of the BDI will expedite the decision-making process and increase the chance of treatment success. Subsequently, the choice and timing of the appropriate reconstructive strategy have a critical role in long-term prognosis. Currently, a wide spectrum of multidisciplinary interventions with different degrees of invasiveness is indicated for BDI management. These World Society of Emergency Surgery (WSES) guidelines have been produced following an exhaustive review of the current literature and an international expert panel discussion with the aim of providing evidence-based recommendations to facilitate and standardize the detection and management of BDIs during cholecystectomy. In particular, the 2020 WSES guidelines cover the following key aspects: (1) strategies to minimize the risk of BDI during cholecystectomy; (2) BDI rates in general surgery units and review of surgical practice; (3) how to classify, stage, and report BDI once detected; (4) how to manage an intraoperatively detected BDI; (5) indications for antibiotic treatment; (6) indications for clinical, biochemical, and imaging investigations for suspected BDI; and (7) how to manage a postoperatively detected BDI.

A novel MSC-based immune induction strategy for ABO-incompatible liver transplantation: a phase I/II randomized, open-label, controlled trial

BACKGROUND

ABO-incompatible liver transplantation (ABO-i LT) has become a rescue therapeutic option for patients with severe hepatic failure. Although the use of rituximab greatly reduces the morbidity of antibody-mediated rejection (AMR), severe adverse effects, such as infection and biliary complications, still seriously threaten the survival of transplant recipients. The aim of this study was to evaluate the safety and feasibility of using mesenchymal stem cells (MSCs) to replace rituximab in ABO-i LT.

METHODS

Twenty-two patients with severe hepatic failure undergoing ABO-i LT were enrolled and randomly divided into two groups: the MSC group and the rituximab group. The safety of the application of MSCs and the incidence of allograft rejection, including antibody-mediated rejection (AMR) and acute cellular rejection (ACR), were evaluated in both groups at the 2-year follow-up period as primary endpoints. Recipients and graft survival and other postoperative complications were compared as secondary endpoints.

RESULTS

No severe MSC-related adverse events were observed during the trial. MSC treatment yielded comparable, if not better, results than rituximab at decreasing the incidence of acute rejection (9.1% vs 27.3%). Inspiringly, compared to those in the rituximab group, the rates of biliary complications (0% vs 45.5%) and infection (9.1% vs 81.8%) were significantly decreased in the MSC group. In addition, there were no significant differences in 2-year graft and recipient survival between the two groups (81.8% vs 72.7%).

CONCLUSIONS

Our data show that MSC transfusion is comparable to rituximab treatment for AMR prophylaxis following ABO-i LT. Additionally, the results indicate that MSCs are more beneficial to the prevention of infection and biliary complications and may be introduced as a novel immunosuppressive approach for ABO-i LT.

TRIAL REGISTRATION

Trial registration: chictr.org.cn , ChiCTR2000037732. Registered 31 August 2020- Retrospectively registered, http://www.chictr.org.cn/showproj.aspx?proj=57074 .

Complications of liver transplant

Liver transplantation has become a definitive treatment for patients with end-stage liver disease and those meeting Milan criteria for hepatocellular carcinoma. The morbidity and mortality associated with liver transplantation continues to decrease thanks to refinements in surgical technique, immunosuppression, and imaging. In particular, imaging plays a vital role by facilitating early detection of post-operative complications and enabling prompt treatment. Post-operative complications that lead to graft failure and patient morbidity/mortality can be generally categorized as vascular, biliary, parenchymal, and malignant. Vascular complications include stenosis and thrombosis of the hepatic artery, portal vein, and inferior vena cava; hepatic artery pseudoaneurysm; arteriovenous fistula; and celiac stenosis. Biliary abnormalities include strictures, bile leak, obstruction, recurrent disease, and infection. While imaging is not primarily utilized to diagnose allograft rejection, it plays an important role in excluding mechanical causes of graft dysfunction that can mimic rejection. Ultrasound is routinely performed as the first-line imaging evaluation for the detection and follow-up of early and delayed complications. Cholangiography and magnetic resonance cholangiopancreatography are useful in detecting and characterizing biliary complications. Computed tomography is often used to further evaluate abnormal findings on ultrasound or for the characterization of post-operative fluid collections. The aim of this review is to discuss and illustrate the imaging findings of complications associated with liver transplantation and their role in facilitating treatment.

Can ultrasonography differentiate anastomotic and non-anastomotic biliary strictures after orthotopic liver transplantation- a single-center experience

PURPOSE

To evaluate the role of ultrasonography (US) in differentiating anastomotic biliary strictures (AS) and non-anastomotic biliary strictures (NAS) after orthotopic liver transplantation (OLT).

METHOD

This retrospective study included 1259 OLT recipients between 2005-2018. Seventy-six with anastomotic strictures (AS) and 103 with non-anastomotic strictures (NAS) were analyzed. The reference standard was cholangiography. The sensitivity, specificity, accuracy of US was evaluated.

RESULTS

There were significant differences between AS and NAS groups (p < 0.001) for skipped and irregular dilatation of intrahepatic bile duct and visualization of hilar biliary lumen. The better US imaging feature for NAS was poorly visualized and non- visible hilar bile duct luminal contour. The sensitivity, specificity and accuracy were 94.2 %, 84.2 % and 88.9 % respectively. Combined two predictors greatly increased the specificity to 93.4 % while diminished its sensitivity and accuracy.

CONCLUSION

US is useful and efficient to differentiate AS and NAS after OLT.

Percutaneous removal of biliary stones post-liver transplant in a pediatric patient: Case report and review of the literature

This case report describes an 8-year-old girl who underwent a segmental LT for a primary diagnosis of citrullinemia at the age of 12 months. She presented with cholangitis secondary to stenosis of the biliary-enteric anastomosis. MRI revealed dilatation of intrahepatic bile ducts associated with multiple stones. An endoscopic approach failed to decompress the bile ducts and remove the stones. A percutaneous approach was then undertaken. After placement of a temporary external biliary drain for 12 days, a 26 French sheath was placed to access the bile ducts. Using a 14Fr flexible cystoscope, 80%-90% of the biliary stones were removed. This was followed by antegrade balloon dilatation of the biliary-enteric anastomosis. Two months later, the procedure was repeated, resulting in complete clearance of the biliary stones. An internal-external biliary drain was maintained in placed for 10 months. The patient has been asymptomatic, with no evidence of stone recurrence for 13 months after drain removal. Percutaneous biliary stone removal is commonly performed in adults with non-transplanted livers, especially in complex cases, and has also been shown to be successful in the pediatric population. However, it is rarely reported in transplanted livers in adults, and to the best of our knowledge, no pediatric cases have been reported. This case illustrates that this technique can be successfully utilized in pediatric LT patients.

Endoscopic Retrograde Cholangiopancreatography: Deciphering the Black and White

Endoscopic Retrograde Cholangiopancreatography (ERCP) remains the conventional method of imaging the pancreatic and biliary tree and is performed by direct injection of iodinated contrast material via the major papilla. This diagnostic procedure gained popularity in the 1970s and subsequently paved way for ERCP guided interventions such as sphincterotomy, stone retrieval and stent placement. Currently, therapeutic ERCP is more widespread than diagnostic ERCP primarily due to the availability of noninvasive imaging. Nevertheless, more than half a million ERCPs are performed annually in the United States and radiologists need to be comfortable interpreting them. The following review will familiarize the reader with the imaging appearances of biliary and pancreatic disorders on conventional ERCP, and elaborate on therapeutic ERCP with illustrative examples.