Hepatic artery thrombosis after orthotopic liver transplantation: a review of nonsurgical causes

Thrombotic complications post liver transplantation: Etiology and management

Liver transplantation (LT) is the life saving therapeutic option for patients with acute and chronic end stage liver disease. This is a routine procedure with excellent outcomes in terms of patient survival and quality of life post LT. Orthotopic LT (OLT) patients require a critical care as they are prone to variety of post-operative vascular, cardiovascular, biliary, pulmonary and abdominal complications. Thrombotic complications (both arterial and venous) are not uncommon post liver transplant surgery. Such vascular problems lead to increased morbidity and mortality in both donor and graft recipient. Although thromboprophylaxis is recommended in general surgery patients, no such standards exist for liver transplant patients. Drastic advancements of surgical and anesthetic procedures have improvised survival rates of patients post OLT. Despite these, haemostatic imbalance leading to thrombotic events post OLT cause significant graft loss and morbidity and even lead to patient’s death. Thus it is extremely important to understand pathophysiology of thrombosis in LT patients and shorten the timing of its diagnosis to avoid morbidity and mortality in both donor and graft recipient. Present review summarizes the current knowledge of vascular complications associated with LT to highlight their impact on short and long-term morbidity and mortality post LT. Also, present report discusses the lacunae existing in the literature regarding the risk factors leading to arterial and venous thrombosis in LT patients.

Donor Atheromatous Disease is a Risk Factor for Hepatic Artery Thrombosis After Liver Transplantation

The increasing age of liver donors and transplant candidates, together with the growing prevalence of metabolic comorbidities, could impact the risk of vascular complications after liver transplantation. We enrolled a consecutive cohort of adult patients undergoing liver transplantation from 2012 to 2021 who had a blinded pathological assessment of atherosclerosis in the donor and recipient hepatic arteries (HA). Patients receiving partial or reduced grafts, retransplantation, or combined organ transplantation were excluded. The relationship between HA atherosclerosis and HA thrombosis after liver transplantation was evaluated using logistic regression in the whole study cohort and in a propensity score-matched subpopulation. Among 443 eligible patients, 272 had a full pathological evaluation of the donor and recipient HA and were included in the study. HA atheroma was present in 51.5% of donors and in 11.4% of recipients. HA thrombosis occurred in 16 patients (5.9%), being more likely in patients who received a donor with HA atherosclerosis than in those without (10.7% vs. 0.8%; p < 0.001). Donor HA atherosclerosis was an independent risk factor of HA thrombosis (OR = 17.79; p = 0.008), and this finding was consistent in the propensity score-matched analysis according to age, sex, complex arterial anastomosis, and alcoholic liver disease (OR = 19.29; p = 0.007). Atheromatous disease in the recipient had no influence on the risk of HA thrombosis (OR = 1.70; p = 0.55). In conclusion, patients receiving donors with HA atherosclerosis are at increased risk for HA thrombosis after liver transplantation. The evaluation of the donor graft vasculature could guide antiplatelet therapy in the postoperative period.

A 29-mRNA host-response classifier identifies bacterial infections following liver transplantation - a pilot study

PURPOSE

Infections are common complications in patients following liver transplantation (LTX). The early diagnosis and prognosis of these infections is an unmet medical need even when using routine biomarkers such as C-reactive protein (CRP) and procalcitonin (PCT). Therefore, new approaches are necessary.

METHODS

In a prospective, observational pilot study, we monitored 30 consecutive patients daily between days 0 and 13 following LTX using the 29-mRNA host classifier IMX-BVN-3b that determine the likelihood of bacterial infections and viral infections. True infection status was determined using clinical adjudication. Results were compared to the accuracy of CRP and PCT for patients with and without bacterial infection due to clinical adjudication.

RESULTS

Clinical adjudication confirmed bacterial infections in 10 and fungal infections in 2 patients. 20 patients stayed non-infected until day 13 post-LTX. IMX-BVN-3b bacterial scores were increased directly following LTX and decreased until day four in all patients. Bacterial IMX-BVN-3b scores detected bacterial infections in 9 out of 10 patients. PCT concentrations did not differ between patients with or without bacterial, whereas CRP was elevated in all patients with significantly higher levels in patients with bacterial infections.

CONCLUSION

The 29-mRNA host classifier IMX-BVN-3b identified bacterial infections in post-LTX patients and did so earlier than routine biomarkers. While our pilot study holds promise future studies will determine whether these classifiers may help to identify post-LTX infections earlier and improve patient management.

CLINICAL TRIAL NOTATION

German Clinical Trials Register: DRKS00023236, Registered 07 October 2020, https://drks.de/search/en/trial/DRKS00023236.

Immunomonitoring via ELISPOT Assay Reveals Attenuated T-Cell Immunity to CMV in Immunocompromised Liver-Transplant Patients

Assessing immune responses to cytomegalovirus (CMV) after liver transplant in patients on immunosuppressive therapy remains challenging. In this study, employing ELISPOT assays, 52 liver-transplant recipients were evaluated for antiviral T-cell activity in peripheral blood mononuclear cells (PBMCs), measuring interferon-γ (IFN-γ) secretion upon stimulation with CMV-specific peptides (CMV peptide pool, CMV IE-1, and pp65 antigens). Parameters such as stimulation index, mean spot size, and mean spot count were measured. The study found that heightened immunosuppression, especially with prednisolone in triple therapy, significantly dampened CMV-specific immune responses. This was demonstrated by decreased IFN-γ production by CMV-specific T-cells (CMV peptide pool: p = 0.036; OR = 0.065 [95% CI: 0.005-0.840], pp65 antigen: p = 0.026; OR = 0.048 [95% CI: 0.003-0.699]). Increased immunosuppression correlated with reduced IFN-γ secretion per cell, reflected in smaller mean spot sizes for the CMV peptide pool (p = 0.019). Notably, shorter post-transplant intervals correlated with diminished antiviral T-cell IFN-γ release at two years (CMV peptide pool: p = 0.019; IE antigen: p = 0.010) and five years (CMV peptide pool: p = 0.0001; IE antigen: p = 0.002; pp65 antigen: p = 0.047), as did advancing age (pp65 antigen: p = 0.016, OR = 0.932, 95% CI: 0.881-0.987). Patients with undetectable CMV antigens had a notably higher risk of CMV reactivation within six months from blood collection, closely linked with triple immunosuppression and prednisolone use. These findings highlight the intricate interplay between immunosuppression, immune response dynamics, and CMV reactivation risk, emphasizing the necessity for tailored immunosuppressive strategies to mitigate CMV reactivation in liver-transplant recipients. It can be concluded that, particularly in the early months post-transplantation, the use of prednisolone as a third immunosuppressant should be critically reconsidered. Additionally, the use of prophylactic antiviral therapy effective against CMV in this context holds significant importance.

Postoperative Bloodstream Infection Is Associated with Early Vascular Complications in Pediatric Liver Transplant Recipients with Biliary Atresia

Bloodstream infection (BSI) after pediatric liver transplantation (PLT) is a common and severe complication that affects patient survival. Children with biliary atresia (BA) are at an increased risk for clinically significant infections. This study evaluated the impact of post-PLT BSI on clinical outcomes in children with BA. A total of 67 patients with BA aged <18 years who underwent PLT between April 2006 and September 2020 were analyzed and divided into two groups according to the occurrence of post-PLT BSI within 1 month (BSI vs. no BSI = 13 [19.4%] vs. 54 [80.6%]). The BSI group was significantly younger at the time of PLT and had a higher frequency of BSI at the time of PLT than the no BSI group. Early vascular complications within 3 months and reoperations were significantly more frequent in the BSI group. Univariate and multivariate analyses revealed that bacteremia within 1 month of PLT and graft-to-recipient weight ratio >4% were significantly associated with vascular complications. In conclusion, BSI after PLT is associated with increased vascular complications and reoperations. Proper control of bacterial infections and early liver transplantation before uncontrolled BSI may reduce vascular complications and unexpected reoperations in children with BA.

Vascular complications after liver transplantation: contemporary approaches to detection and treatment. A literature review

Vascular complications (VCs) after liver transplantation (LT) are rare but are one of the most dreaded conditions that can potentially lead to graft loss and recipient death. This paper has analyzed the international experience in the early diagnosis of various VCs that can develop following LT, as well as the optimal timing and methods of treatment of these complications.

The Impact of Hepatic Artery Thrombosis on the Outcome of Pediatric Living Donor Liver Transplantations

The aim of our study was to assess risk factors for hepatic artery thrombosis (HAT) and to evaluate the impact of HAT management on long-term outcomes after pediatric living donor liver transplantation (LDLT). We retrospectively analyzed 400 patients who underwent primary LDLT between 1999 and 2020. We compared preoperative data, surgical factors, complications, and patient and graft survivals in patients with HAT (HAT Group) and without HAT (non-HAT Group). A total of 27 patients (6.75%) developed HAT. Acute liver failure, a hepatic artery (HA) anastomosis diameter below 2 mm, and intraoperative HA flow dysfunction were significantly more common in the HAT Group (p < 0.05, p = 0.02026, and p = 0.0019, respectively). In the HAT Group, 21 patients (77.8%) underwent urgent surgical revision. The incidence of biliary stenosis and retransplantation was significantly higher in the HAT Group (p = 0.00002 and p < 0.0001, respectively). Patient and graft survivals were significantly worse in the HAT Group (p < 0.05). The close monitoring of HA flow with Doppler ultrasound during the critical period of 2 to 3 weeks after LDLT and the immediate attempt of surgical revascularization may attenuate the elevated risk of biliary stenosis, graft loss, and the need for retransplantation due to HAT.

Real-world effectiveness of preemptive therapy (PET) for cytomegalovirus (CMV) disease prevention in CMV high-risk donor seropositive/recipient seronegative (D+R-) liver transplant recipients (LTxR)

BACKGROUND

Despite superiority of preemptive therapy (PET) compared to universal prophylaxis for prevention of cytomegalovirus (CMV) disease in the CAPSIL randomized trial among CMV D+R- liver transplant recipients (LTxRs), real-world effectiveness may be lower because of logistical concerns about feasibility of PET.

METHODS

We retrospectively assessed PET as standard clinical care at a single transplant center among 50 consecutive adult CMV D+R- LTxRs undergoing a first liver transplant between 4/4/2019 and 5/18/2021 and compared outcomes and adherence to those randomized to PET in the CAPSIL study (N = 100). The primary outcome was CMV disease and secondary outcomes were biopsy-confirmed acute allograft rejection, retransplant, invasive fungal infections, and death, all assessed by 1-year post-transplant. Exploratory outcomes included virologic parameters and measures of adherence to protocol-specified CMV qPCR monitoring.

RESULTS

Baseline characteristics were similar between groups. The cumulative incidence of CMV disease at 1-year post-transplant was 4/50 (8%) versus 9/100 (9%) in the real-world and CAPSIL cohorts, respectively, p = 1.0. The rate of breakthrough CMV disease during the 100-day PET period was low (2/50 [4%]) and similar to the PET cohort from the CAPSIL study (3/100 [3%]).  All secondary and exploratory outcomes were not significantly different between the real-world and CAPSIL PET cohorts.

CONCLUSIONS

In this first reported study of real-world PET, the feasibility and effectiveness for CMV disease prevention and for other clinical outcomes in CMV D+R- LTxRs were similar to those reported with PET in a clinical trial. Additional studies to confirm feasibility and generalizability in other settings are warranted.

Post-Transplantation Cytomegalovirus Infection Interplays With the Development of Anastomotic Biliary Strictures After Liver Transplantation

Background: Anastomotic biliary stricture (ABS) remains the most frequent complication after liver transplantation (LT). This study aimed to identify new anastomotic biliary stricture risk factors, with a specific focus on postoperative events. Additionally, ABS management and impact on patient and graft survival were assessed.

Methods: All consecutive patients who underwent LT with duct-to-duct anastomosis between 2010 and 2019 were included. All patients who died within 90 days after LT due to non-ABS-related causes were excluded.

Results: Among 240 patients, 65 (27.1%) developed ABS after a median time of 142 days (range, 13–1265). Median follow-up was 49 months (7–126). Upon multivariable analysis, donor BMI (OR=0.509, p = 0.037), post-LT CMV primoinfection (OR = 5.244, p &lt; 0.001) or reactivation (OR = 2.421, p = 0.015) and the occurrence of post-LT anastomotic biliary fistula (OR = 2.691, p = 0.021) were associated with ABS. Anastomotic technical difficulty did not independently impact the risk of ABS (OR = 1.923, p = 0.051). First-line ABS treatment was systematically endoscopic (100%), and required a median of 2 (range, 1–11) procedures per patient. Repeat LT was not required in patients developing ABS. The occurrence of ABS was not associated with overall patient survival (p = 0.912) nor graft survival (p = 0.521).

Conclusion: The risk of developing ABS after LT seems driven by the occurrence of postoperative events such as CMV infection and anastomotic fistula. In this regard, the role of CMV prophylaxis warrants further investigations.

Consensus Statement on Hemostatic Management, Anticoagulation, and Antiplatelet Therapy in Liver Transplantation

Anticoagulation and antiplatelet therapies are increasingly used in liver transplant (LT) candidates and recipients due to cardiovascular comorbidities, portal vein thrombosis, or to manage posttransplant complications. The implementation of the new direct-acting oral anticoagulants and the recently developed antiplatelet drugs is a great challenge for transplant teams worldwide, as their activity must be monitored and their complications managed, in the absence of robust scientific evidence. In this changing and clinically heterogeneous scenario, the Spanish Society of Liver Transplantation and the Spanish Society of Thrombosis and Haemostasis aimed to achieve consensus regarding the indications, drugs, dosing, and timing of anticoagulation and antiplatelet therapies initiated from the inclusion of the patient on the waiting list to post-LT surveillance. A multidisciplinary group of experts composed by transplant hepatologists, surgeons, hematologists, transplant-specialized anesthesiologists, and intensivists performed a comprehensive review of the literature and identified 21 clinically relevant questions using the patient-intervention-comparison-outcome format. A preliminary list of recommendations was drafted and further validated using a modified Delphi approach by a panel of 24 transplant delegates, each representing a LT institution in Spain. The present consensus statement contains the key recommendations together with the core supporting scientific evidence, which will provide guidance for improved and more homogeneous clinical decision making.

Hepatic Artery Thrombosis After Orthotopic Liver Transplant: Experience in the Last 10 Years

BACKGROUND

Hepatic artery thrombosis (HAT) is the second cause of graft failure, after primary disfunction. It has a significant morbidity, with a retransplant and mortality rate in early hepatic artery thrombosis of 50%. The incidence of this event goes from 2% to 9% in the adult population.

METHODS

The objective is to assess the incidence of HAT in a third-level hospital. The study design is an observational retrospective study, collecting data of the transplant recipient from 2010 to 2020.

RESULTS

Incidence of HAT was 5.33% (39/732). A statistical difference was found with the blood intraoperative administration (P = .002) and with the presence of anatomic abnormalities in the hepatic artery between the HAT and the non-HAT group. We did not find any statistical difference with portal thrombosis (P = .73) between the groups.

CONCLUSIONS

HAT is a fatal complication after an orthotopic liver transplant, which can lead to graft loss and even recipient death. For these reasons, we should early identify risk factors associated with this event early and try to minimize them to avoid the devastating consequences.

Rescue Thrombectomy for Early Hepatic Artery Thrombosis Using Stent Retriever in a Child Post Combined Deceased Donor Liver and Renal Transplant

We report this case of a 5-year-old child post combined liver and renal transplant for primary hyperoxaluria. Patient developed hepatic artery thrombosis on day 3 posttransplant that was managed by reexploration and reanastomosis of the hepatic artery. On day 4, the patient again developed hepatic artery thrombosis that failed to revascularize by surgical exploration and reanastomosis. Tissue plasminogen activator was injected into the hepatic artery intraoperatively to lyse any clot; however, no revascularization could be achieved. Subsequently, catheter angiogram confirmed no flow in the hepatic artery. A4 × 22 mm revive stent retriever was deployed across the site of occlusion and retrieved after 5 minutes of indwell time. Two such passes were made and complete recanalization of the hepatic artery was achieved. The hepatic artery remained patent as confirmed on serial Doppler images post intervention.

Automatic Liver Viability Scoring with Deep Learning and Hyperspectral Imaging

Hyperspectral imaging (HSI) is a non-invasive imaging modality already applied to evaluate hepatic oxygenation and to discriminate different models of hepatic ischemia. Nevertheless, the ability of HSI to detect and predict the reperfusion damage intraoperatively was not yet assessed. Hypoxia caused by hepatic artery occlusion (HAO) in the liver brings about dreadful vascular complications known as ischemia-reperfusion injury (IRI). Here, we show the evaluation of liver viability in an HAO model with an artificial intelligence-based analysis of HSI. We have combined the potential of HSI to extract quantitative optical tissue properties with a deep learning-based model using convolutional neural networks. The artificial intelligence (AI) score of liver viability showed a significant correlation with capillary lactate from the liver surface (r = −0.78, p = 0.0320) and Suzuki’s score (r = −0.96, p = 0.0012). CD31 immunostaining confirmed the microvascular damage accordingly with the AI score. Our results ultimately show the potential of an HSI-AI-based analysis to predict liver viability, thereby prompting for intraoperative tool development to explore its application in a clinical setting.

Early Hepatic Artery Thrombosis After Living Donor Liver Transplant: A 13-Year Single-Center Experience in Jordan

OBJECTIVES

Early hepatic artery thrombosis is a serious complication that may follow living donor liver transplant. Acute graft loss and patient morbidity and mortality are possible consequences. The therapeutic algorithm includes surgical or interventional revascularization, conservative approaches, or retransplantation.

MATERIALS AND METHODS

Among 155 patients who underwent living donor liver transplant at our transplant center from 2004 to 2020, there were 5 who developed hepatic artery thrombosis. From our 13- year experience, we herein present their demographic and clinical characteristics, radiological imaging findings, perioperative courses, and the postoperative follow-up.

RESULTS

All patients displayed advanced liver disease with a Child-Pugh score of C and a mean Model for End-Stage Liver Disease score of 32. Underlying causes for end-stage liver disease included hepatitis B and C infection and cryptogenic liver cirrhosis. The mean patient age was 49 years; 2 patients were female. Living donor liver transplant was performed with donor tissue from immediate kin, according to Jordanian allocation rules. The diagnosis of hepatic artery thrombosis was made by Doppler ultrasonography and confirmed via computed tomography. After surgical revision of the anastomosis, our first patient experienced thrombotic recurrence. All patients received interventional catheterization with local thrombolysis and subsequently developed rethrombosis. Despite prevalent thrombosis, 4 patients achieved long-term survival without further deterioration of liver function. Cumulative 1-year, 5-year, and 10-year survival rates were 80%, 80%, and 60%, respectively. Spontaneous recanalization of the hepatic artery was observed in 1 patient.

CONCLUSIONS

Favorable long-term outcomes are achievable in patients with persistent hepatic artery thrombosis. When retransplant is not feasible and interventional approaches fail, conservative treatment with careful observation of liver function should be implemented. Attentive observation of collateral circulation toward the liver, distal of the thrombosis, may be beneficial to both graft and patient survival.

Cytomegalovirus Hepatitis in Immunocompetent and Immunocompromised Hosts

Human cytomegalovirus (HCMV) infection is common and affects between 40-100% of the worldwide population. However, the majority of cases are asymptomatic and when severe disease occurs, it is usually restricted to immunocompromised patients. Liver involvement by HCMV differs significantly, accordingly to the immune status of the host. In immunocompromised patients, particularly liver transplant patients, it often causes clinically significant hepatitis. On the other hand, in immunocompetent patients, HCMV hepatitis requiring hospitalization is extremely rare. This review aims to appraise studies regarding the pathophysiology of HCMV hepatitis, including mechanisms of latency and reactivation and its contribution to disease development, clinical presentation, diagnostic modalities and treatment, with a focus on comparing different aspects between immunocompromised and immunocompetent hosts.

Plasma cytomegalovirus DNA load predicts outcomes in liver transplant recipients

Objective

Cytomegalovirus (CMV) infection has a significant negative impact on liver transplant (LT) recipients. We aimed to evaluate the efficacy of real‐time DNA quantitative polymerase chain reaction (qPCR) in the early detection of CMV and predicting post‐transplant outcomes.

Materials and Methods

This was a retrospective study that enrolled a total of 49 adult LT recipients between December 2016 and October 2019. Serial CMV qPCR were tested weekly. We used operating characteristic curve analysis to quantify qPCR replication numbers to decide the optimal threshold to predict posttransplant complications and overall survival.

Results

The optimal cut‐off value of 180 copies/ml (=164 IU/ml) was determined. We had 40 patients in the low qPCR group (<180 copies/ml) and nine patients in the high qPCR group (≥180 copies/ml). Higher qPCR was associated with more severe CMV disease, early allograft dysfunction, major posttransplant complications, longer ICU stays, and lower 2‐year overall survival (OS; all p < .05). In the univariate logistic regression model, persistent DNAemia ≥ 4 weeks after anti‐CMV treatment, coexisted bacterial and/or fungal infection, and high CMV qPCR ≥ 180 copies/ml with p < .100. High CMV qPCR ≥ 180 copies/ml (p = .016; hazard ratio [HR] = 19.5; 95% confidence interval [CI] = 1.73–219.49) remained to be the only independent risk factors for major complication by the multivariate analysis. The overall 2‐year OS rates were 92.5% and 66.7% in the low and the high qPCR group, respectively (p = .030).

Conclusion

Our findings support evidence that qPCR is effective in detecting CMV infection provides an objective perspective in predicting posttransplant outcomes. High plasma CMV DNA load (defined as CMV qPCR ≥ 180 copies/ml or 164 IU/ml) not only indicates a hazard in developing major posttransplant complications but also associates with prolonged and refractory treatment courses.

Medical care of liver transplant patients

INTRODUCTION

Liver transplantation is a life-changing event for patients and survival following transplantation has improved significantly since the first transplantation in 1967. Following liver transplantation, patients face a unique set of healthcare management decisions including transplantation-specific complications, recurrence of primary liver disease, as well as metabolic and malignancy concerns related to immunosuppression. As more patients with liver disease receive transplantation and live longer, understanding and managing these patients will require not only transplant specialist but also local subspecialist and primary care physicians.

AREAS COVERED

This review covers common issues related to the management of patients following liver transplantation including immunosuppression, liver allograft dysfunction, metabolic complications, as well as routine health maintenance such as immunizations and cancer screening.

EXPERT OPINION

Optimizing medical care for patients following liver transplant will benefit from ensuring all providers, not just transplant specialist, have a basic understanding of the common issues encountered in the post-transplant patient. This review provides an overview of common healthcare concerns and management options for patients following liver transplantation.

Inositol 1,4,5-trisphosphate receptor type 3 plays a protective role in hepatocytes during hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury is seen in a variety of clinical conditions, including hepatic thrombosis, systemic hypotension, and liver transplantation. Calcium (Ca²⁺) signaling mediates several pathophysiological processes in the liver, but it is not known whether and how intracellular Ca²⁺ channels are involved in the hepatocellular events secondary to ischemia-reperfusion. Using an animal model of hepatic ischemia-reperfusion injury, we observed a progressive increase in expression of the type 3 isoform of the inositol trisphosphate receptor (ITPR3), an intracellular Ca²⁺ channel that is not normally expressed in healthy hepatocytes. ITPR3 expression was upregulated, at least in part, by a combination of demethylation of the ITPR3 promoter region and the increased transcriptional activity of the nuclear factor of activated T-cells (NFAT). Additionally, expression of pro-inflammatory interleukins and necrotic surface area were less pronounced in livers of control animals compared to liver-specific ITPR3 KO mice subjected to hepatic damage. Corroborating these findings, ITPR3 expression and activation of NFAT were observed in hepatocytes of liver biopsies from patients who underwent liver ischemia caused by thrombosis after organ transplant. Together, these results are consistent with the idea that ITPR3 expression in hepatocytes plays a protective role during hepatic injury induced by ischemia-reperfusion.

Imaging post liver transplantation part I: vascular complications

Liver transplantation continues to rise in frequency, with over 1,000 procedures performed in the UK in 2018. Complications are increasingly uncommon but when they occur, early recognition and intervention is vital to save grafts. Imaging after the perioperative period is often performed at patients' local hospitals meaning that all radiologists and sonographers need to have an understanding of how to assess a transplant liver. Part I of this series will focus on vascular complications, including the normal postoperative vascular anatomy following liver transplantation, normal post-transplantation vascular imaging findings and abnormal findings that may prompt further investigation. Vascular complications following liver transplantation will be illustrated using a collection of cases.

Pyogenic liver abscess in liver transplant recipient: A warning signal for the risk of recurrence and retransplantation

BACKGROUND

Pyogenic liver abscesses in liver transplant recipients (PLA-LTR) are a rare disease whose specificities compared with PLA in non-transplanted patients (PLA-C) are unknown.

METHODS

A retrospective case-control study was conducted in a French academic hospital from January 1, 2010, to December 31, 2014.

RESULTS

Among 176 patients diagnosed with PLA, 14 were LTR; each case was matched with 3 PLA-C controls by date of PLA diagnosis and pathophysiological mechanism of PLA. Median time from liver transplantation to PLA diagnosis was 34.5 months. Among 14 PLA-LTR, 8/14 (57.1%) had bacteremia and 10/14 (71.4%) had positive PLA cultures. Most commonly isolated bacteria were Enterobacteriaceae (9/14; 64.3%), Enterococcus spp. (4/14; 28.6%), and anaerobic bacteria (3/14; 21.4%). Clinical, radiological, and microbiological characteristics did not significantly differ between PLA-LTR and PLA-C but there was a tendency toward more diabetic patients and a less acute presentation. All but one PLA-LTR were associated with ischemic cholangitis, whereas this was a rare cause among PLA-C (13/14 vs 3/42, respectively, P < .001) among patients with PLA-LTR. In contrast, hepatobiliary neoplasia was rare in PLA-LTR but frequent in PLA-C (1/14 vs 24/42, P = .001). No significant difference was found between PLA-LTR and PLA-C in terms of duration of antibiotic therapy (6.5 and 6 weeks, respectively), PLA drainage rates (10/14 and 26/42, respectively), or mortality at 12 months after PLA diagnosis (2/14 and 5/42, respectively). Recurrence rates within the first year were observed in 6/14 patients (42.9%), and retransplantation was needed in 5/14 (35.7%).

CONCLUSIONS

Occurrence of PLA in LTR is a severe event leading to high risk of recurrence and retransplantation.

Post liver transplant recurrent and de novo viral infections

Survival following liver transplantation has changed dramatically owing to improvement in surgical techniques, peri-operative care and optimal immunosuppressive therapy. Post-Liver transplant (LT) de novo or recurrent viral infection continues to cause major allograft dysfunction, leading to poor graft and patient survival in untreated patients. Availability of highly effective antiviral drugs has significantly improved post-LT survival. Patients transplanted for chronic hepatitis B infection should receive life-long nucleos(t)ide analogues, with or without HBIg for effective viral control. Patients with chronic hepatitis C should be commenced on directly acting antiviral (DAA) drugs prior to transplantation. DAA therapy for post-LT recurrent hepatitis C infection is associated with close to 100% sustained virological response (SVR), irrespective of genotype. De novo chronic Hepatitis E infection is an increasingly recognised cause of allograft dysfunction in LT recipients. Untreated chronic HEV infection of the graft may lead to liver fibrosis and allograft failure. CMV and EBV can reactivate leading to systemic illness following liver transplantation. With COVID-19 pandemic, post-transplant patients are at risk of SARS-Co-V2 infection. Majority of the LT recipients require hospitalization, and the mortality in this population is around 20%. Early recognition of allograft dysfunction and identification of viral aetiology is essential in the management of post-LT de novo or recurrent infections. Optimising immunosuppression is an important step in reducing the severity of allograft damage in the treatment of post-transplant viral infections. Viral clearance or control can be achieved by early initiation of high potency antiviral therapy.

Impact of ABO-incompatibility on hepatic artery thrombosis in living donor liver transplantation

Background

The current era of rituximab-based regimens brought improved survival in ABO-incompatible (ABO-I) living donor liver transplantation (LDLT). Nevertheless, the actual risk for hepatic artery thrombosis (HAT) still remains to be investigated. The aim of this study was to evaluate the impact of ABO-incompatibility on HAT in adult LDLT patients.

Methods

Patients who received ABO-I LDLT were compared to those who received ABO-compatible (ABO-C) LDLT with a special focus on HAT.

Results

A total of 378 patients underwent LDLT from January 2012 to February 2018. Of those, ABO-I LDLT was performed in 78 consecutive patients. The other 300 patients with ABO-C LDLT constituted the comparator group. No significant differences were observed between the two groups in baseline and perioperative characteristics. HAT occurred in 11 (2.9%) patients, 2 and 9 patients in ABO-I and ABO-C LDLT groups, respectively, which didn't show any significant difference between the two groups (P=0.84). All were categorized into early HAT. Immediate revascularization by intraarterial thrombolysis was successfully employed in 8 patients. Surgical revision of anastomosis and retransplantation were performed in 1 and 2 patients, respectively. No one-year mortality was related to HAT in the two groups. The overall outcomes including biliary complications made no significant difference between the two groups.

Conclusions

ABO-incompatibility has no adverse impact on the incidence and treatment outcome of HAT in the current rituximab-based desensitization.

Antithrombin III in the prevention of thrombotic complications in high risk patients undergoing liver transplantation

Introduction. Recent studies have indicated an increased incidence of thrombotic vascular complications after liver transplantation. The reasons may be associated with surgical technique and “unbalanced” hemostasis in patients with diffuse liver diseases. The imbalance is determined by the deficiency of physiological procoagulants and anticoagulants due to a reduced protein-synthesis function of the liver in chronic hepatocyte injury. At the same time, 90% of all spontaneous antithrombin activity is associated with antithrombin III.

Aim. The aim of the study was to evaluate the efficacy of using antithrombin III concentrate in liver transplant patients.

Material and methods. A retrospective study included 46 patients undergoing liver transplantation who had nonocclusive thrombosis in the portal vein system prior to surgery and postoperative venous or arterial thrombosis.

Results. The treatment results were compared between the group with antithrombin III concentrate and the control group in patients with portal vein thrombosis before surgery and postoperative venous or arterial thrombosis; the antithrombin III activity dynamics in the early postoperative period was assessed; the incidence of infectious, and vascular complications and the mortality rates were analyzed.

Conclusion. The antithrombin III concentrate administration during liver transplantation and in the postoperative period contributes to a rapid normalization of antithrombin III activity in blood, the decrease in mortality and in the incidence of infectious and thrombotic complication rates.

Severe Sepsis in Pediatric Liver Transplant Patients: The Emergence of Multidrug-Resistant Organisms

OBJECTIVES

To describe characteristics of liver transplant patients with severe sepsis in the PICU.

DESIGN

Retrospective descriptive analysis.

SETTING

Tertiary children's hospital PICU.

PATIENTS

Liver transplant recipients admitted January 2010 to July 2016 for pediatric severe sepsis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Between January 2010 and July 2016, 173 liver transplants were performed, and 36 of these patients (21%) were admitted with severe sepsis (54 episodes total). Median age at admission was 2 years (1-6.5 yr), 47.2% were male. Bacterial infections were the most common (77.8%), followed by culture negative (12.9%) and viral infections (7.4%). Fungal infections accounted for only 1.9%. Median time from transplant for viral and culture negative infections was 18 days (8.25-39.75 d) and 25 days (9-41 d), whereas 54.5 days (17-131.25 d) for bacterial infections. Bloodstream and intra-abdominal were the most common bacterial sites (45% and 22.5%, respectively). Multidrug-resistant organisms accounted for 47.6% of bacterial sepsis. Vancomycin-resistant Enterococcus and extended-spectrum beta-lactamase producers were the most frequently identified multidrug-resistant organisms. Patients with multidrug-resistant organism sepsis demonstrated higher admission Pediatric Logistic Organ Dysfunction scores (p = 0.043) and were noted to have an odds ratio of 3.8 and 3.6 for mechanical ventilation and multiple organ dysfunction syndrome, respectively (p = 0.047 and p = 0.044). Overall mortality was 5.5% (n = 2 patients), with both deaths occurring in multidrug-resistant organism episodes.

CONCLUSIONS

We report that multidrug-resistant organisms are increasingly being identified as causative pathogens for sepsis in pediatric liver transplant recipients and are associated with significantly higher odds for mechanical ventilation and higher organ failure. The emergence of multidrug-resistant organism infections in pediatric liver transplant patients has implications for patient outcomes, antibiotic stewardship, and infection prevention strategies.

Infections in Liver Transplantation

Liver transplantation has become an important treatment modality for patients with end-stage liver disease/cirrhosis, acute liver failure, and hepatocellular carcinoma. Although surgical techniques and immunosuppressive regimens for liver transplantation have improved significantly over the past 20 years, infectious complications continue to contribute to the morbidity and mortality in this patient population. The use of standardized screening protocols for both donors and recipients, coupled with targeted prophylaxis against specific pathogens, has helped to mitigate the risk of infection in liver transplant recipients. Patients with chronic liver disease and cirrhosis have immunological deficits that place them at increased risk for infection while awaiting liver transplantation. The patient undergoing liver transplantation is prone to develop healthcare-acquired infections due to multidrug-resistant organisms that could potentially affect patient outcomes after transplantation. The complex nature of liver transplant surgery that involves multiple vascular and hepatobiliary anastomoses further increases the risk of infection after liver transplantation. During the early post-transplantation period, healthcare-acquired bacterial and fungal infections are the most common types of infection encountered in liver transplant recipients. The period of maximal immunosuppression that occurs at 1–6 months after transplantation can be complicated by opportunistic infections due to both primary infection and reactivation of latent infection. Severe community-acquired infections can complicate the course of liver transplantation beyond 12 months after transplant surgery. This chapter provides an overview of liver transplantation including indications, donor-recipient selection criteria, surgical procedures, and immunosuppressive therapies. A focus on infections in patients with chronic liver disease/cirrhosis and an overview of the specific infectious complications in liver transplant recipients are presented.

Efficacy and safety of partial splenic embolization for hypersplenism in pre- and post-liver transplant patients: A 16-year comparative analysis

PURPOSE

To report the effect of partial splenic embolization (PSE) on hematological indices and the procedure's safety in pre- and post-liver transplant (LT) patients.

MATERIALS AND METHODS

A single-center retrospective study evaluating all patients who underwent PSE over a 16-year period was performed. Inclusion criteria were splenomegaly confirmed by imaging and at least one of the following cytopenias: hemoglobin ≤10 g/dL, WBC count ≤1500 μL^-1, or platelet count ≤100,000 μL^-1. 38 of 102 patients (37%) met criteria (24 pre- and 14 post-LT) for a total of 40 PSEs.

RESULTS

No effect was seen on median hemoglobin beyond 2 weeks post-PSE. There was a significant and sustained increase in median WBC counts (from 3400 μL^-1 to 5400 μL^-1 at 2 years) and platelet count (from 65,000 μL^-1 to 117,000 μL^-1 at 3.5 years). In 6 out of 40 PSEs (15%) a major complication occurred which included pleural effusion, ascites, spontaneous bacterial peritonitis, pneumonia, and inferior vena cava thrombus. Similar efficacy was observed in pre- and post-LT cohorts, with a trend toward higher complication rate in pre-LT patients.

CONCLUSIONS

PSE is efficacious in increasing WBC count out to 2 years and platelet count out to 3.5 years in patients with hypersplenism. Efficacy and safety appeared independent of pre- or post-LT status. The intervention is associated with major complications and special care should be taken when selecting patients for PSE.

Risk factors and outcomes of pyogenic liver abscess in adult liver recipients: a matched case-control study

BACKGROUND

Adult liver recipients (ALR) differ from the general population with pyogenic liver abscess (PLA) as they exhibit: reconstructed biliary anatomy, recurrent hospitalizations, poor clinical condition and are subjected to immunosuppression. The aim of this study was to identify risk factors associated with PLA in ALR and to analyze the management experience of these patients.

METHODS

Between 1996 and 2016, 879 adult patients underwent liver transplantation (LT), 26 of whom developed PLA. Patients and controls were matched according to the time from transplant to abscess in a 1 to 5 relation. A logistic regression model was performed to establish PLA risk factors considering clusters for matched cases and controls. Risk factors were identified and a multivariate regression analysis performed.

RESULTS

Patients with post-LT PLA were more likely to have lower BMI (p = 0.006), renal failure (p = 0.031) and to have undergone retransplantation (p = 0.002). A history of hepatic artery thrombosis (p = 0.010), the presence of Roux en-Y hepatojejunostomy (p < 0.001) and longer organ ischemia time (p = 0.009) were independent predictors for the development of post-LT PLA. Five-year survival was 49% (95%CI 28-67%) and 89% (95%CI 78%-94%) for post-LT PLA and no post-LT PLA, respectively (p < 0.001).

CONCLUSION

history of hepatic artery thrombosis, the presence of hepatojejunostomy and a longer ischemia time represent independent predictors for the development of post-LT PLA. There was a significantly poorer survival in patients who developed post-LT PLA compared with those who did not.

Cytomegalovirus infection in living donor liver transplant recipients significantly impacts the early post-transplant outcome: A single center experience

BACKGROUND

Cytomegalovirus (CMV) is the most common viral infection in liver transplant recipients that influences the outcomes of liver transplantation. However, its impact on early outcomes following living donor liver transplantation (LDLT) is not fully defined in the Indian subcontinent. This study was done to assess the impact of CMV infection on early post-transplant outcomes in LDLT recipients.

METHODS

Out of 272 LDLTs performed from January 2012 to April 2013, 151 recipients underwent CMV viral load analysis in plasma within 90 days post LDLT based on clinical suspicion. Patients with CMV infection (n = 55) were compared with those without CMV infection (n = 96).

RESULTS

The median time interval of CMV infection from LDLT was 25 days (range 2-90 days). The mean age of study population was 48.92 years. About 116 (76.8%) of the patients were male. Hepatitis C virus (HCV) (39.1%)-related chronic liver disease (CLD) was most common indication for liver transplant. No statistically significant difference was observed in etiology of liver disease (P = .38), Chid-Turcotte-Pugh (CTP) (P = .41), and Model for End-stage Liver Disease (MELD) (P = .12) scores between the groups. Patients with CMV infection had significantly higher incidence of acute cellular rejection (16.1% vs 5.4%, P = .02); longer ICU stay (P = .01); and a higher overall 90-day mortality (24.2% vs 6.7%, P = .001). Bacteremia and fungemia were significantly more common in the CMV infection group.

CONCLUSION

Cytomegalovirus infection significantly influences the early post LDLT outcomes and contributes to increased overall mortality.

Impact of aberrant left hepatic artery ligation on the outcome of liver transplantation

The preservation of a graft's aberrant left hepatic artery (LHA) during liver transplantation (LT) ensures optimal vascularization of the left liver but can also be considered a risk factor for hepatic artery thrombosis (HAT). In contrast, ligation of an aberrant LHA may lead to hepatic ischemia with the potential risk of graft dysfunction and biliary complications. The aim of this study was to prospectively analyze the impact on the surgical strategy for LT of 5 tests performed to establish whether an aberrant LHA was an accessory or a replaced artery, thus leading to the design of a decisional algorithm. From August 2005 to December 2016, 395 whole LTs were performed in 376 patients. Five parameters were evaluated to determine whether an aberrant LHA was an accessory or a replaced artery. On the basis of our decision algorithm, an aberrant LHA was ligated during surgery when assessed as accessory and preserved when assessed as replaced. A total of 138 anatomical variants of hepatic arterial vascularization occurred in 120/395 (30.4%) grafts. Overall, the incidence of an aberrant LHA was 63/395 (15.9%). The LHA was ligated in 33 (52.4%) patients and preserved in 30 (47.6%) patients. After a mean follow-up period of 50.9 ± 39.7 months, the incidence of HAT, primary nonfunction, early allograft dysfunction, biliary stricture or leaks, and overall survival was similar in the 2 groups. In conclusion, once shown to be an accessory, an LHA can be safely ligated without clinical consequences on the outcome of LT. Liver Transplantation 24 204-213 2018 AASLD.

Coagulation Management During Liver Transplantation: Use of Fibrinogen Concentrate, Recombinant Activated Factor VII, Prothrombin Complex Concentrate, and Antifibrinolytics

Coagulation management, and transfusion practice in liver transplantation (LT) have been evolving in the recent years due to better understanding of coagulation abnormalities in end-stage liver disease, and clinical management of LT patients. Avoidance of allogeneic blood components is feasible in some patients, but multi-modal coagulation therapies may be necessary in others who develop complex coagulopathy due to hemorrhage, hemodilution, hypothermia, and acid-base disturbances. Transfusions of plasma and cryoprecipitate remain to be the mainstay therapy for procoagulant factor replacement during LT. Clinical efficacy and safety of these products are limited by logistic issues (eg, thawing), and mostly noninfectious complications. Considering potential alternatives to conventional transfusion is thus important to improve hemostatic resuscitation in complex LT cases. The present review is mainly focused on procoagulant properties of plasma and platelet transfusion, and currently available plasma-derived and recombinant factor concentrates, and antifibrinolytic agents in LT patients. The role of viscoelastic coagulation tests to guide specific component therapies will be also discussed.

Thrombosis after liver transplantation for hepatocellular carcinoma

The influence of thrombosis on the prognosis of patients with hepatocellular carcinoma (HCC) after liver transplantation (LT) and the role of the commonest inherited thrombophilia abnormalities factor V Leiden and prothrombin G20210A in the development of thrombosis are unknown. We investigated a cohort of patients who underwent LT for HCC with the aim to estimate the incidence rate (IR) of thrombosis, its influence on mortality and re-transplantation rates and, in the frame of a nested case-control study, the role of thrombophilia in donors and recipients for the development of thrombosis. Four-hundred and thirty patients underwent LT and were followed for a median of 7.2 years. Twenty-six recipients (6%) developed thrombosis (IR 1.06 [95%CI: 0.71–1.53] per 100 pts-yr). Mortality rate after LT was 3.95 (95%CI: 3.22–4.79) per 100 pts-yr and was not influenced by thrombosis. Re-transplantation was planned for 33 patients and was more common in patients with thrombosis than in those without (HR 2.50 [95%CI: 0.87–7.17]). The risk of thrombosis was 4 times higher in recipients with thrombophilia than in those without (OR 4.23 [95%CI: 0.99–18.04]) and 6 times higher when the analysis was restricted to venous thrombosis (OR 6.26 [95%CI: 1.19–32.85]). The presence of inherited thrombophilia in the donors did not increase the risk of thrombosis of the recipient. In conclusion, thrombosis is a complication of 6% of patients transplanted for HCC and increases the risk of re-transplantation but not of mortality. The risk of thrombosis, particularly venous, is increased in the presence of thrombophilia abnormalities in the recipients.

Cytomegalovirus Infection in Liver Transplant Recipients: Current Approach to Diagnosis and Management

Cytomegalovirus (CMV) infection is the most common viral infection in liver transplant recipients, affecting post-transplant patients and graft survival. Recent advances in diagnosis and management of CMV have led to marked reduction in incidence, severity, and its associated morbidity and mortality. CMV DNA assay is the most commonly used laboratory parameter to diagnose and monitor CMV infection. Current evidence suggests that both pre-emptive and universal prophylaxis approaches are equally justified in liver transplant recipients. Intravenous ganciclovir and oral valganciclovir are the most commonly used drugs for treatment of CMV disease. Most of the centre use valganciclovir prophylaxis for prevention of CMV disease in liver trasplant recipient. The aim of this article is to review the current standard of care for diagnosis and management of CMV disease in liver transplant recipients.

Reducing the incidence of hepatic artery thrombosis in pediatric liver transplantation: Effect of microvascular techniques and a customized anticoagulation protocol

We aimed to assess the incidence of HAT over three eras following implementation of microvascular techniques and a customized anticoagulation protocol in a predominantly cadaveric split liver transplant program. We retrospectively reviewed pediatric liver transplants performed between April 1986 and 2016 and analyzed the incidence HAT over three eras. In E1, 1986-2008, each patient received a standard dose of 5 U/kg/h of heparin and coagulation profiles normalized passively. In E2, 2008-2012, microvascular techniques were introduced. In E3, 2012-2016, in addition, a customized anticoagulation protocol was introduced which included replacement of antithrombin 3, protein C and S, and early heparinization. A total of 317 liver transplants were completed during the study period, with a median age of 31.7 months. In E1, 22% of grafts were cadaveric in situ split grafts, while the second and third eras used split grafts in 59.0% and 64.9% of cases, respectively. HAT occurred in 9.5% in the first era, 11.5% (P=.661) in the second, and dropped to 1.8% in the third era (P=.043). A routine anticoagulation protocol has significantly reduced the incidence of HAT post-liver transplantation in children in a predominantly cadaveric in situ split liver transplant program.

The role of arterial conduits for revascularisation in adult orthotopic liver transplantation

The successful outcome in orthotopic liver transplantation (OLT) is critically dependent on the uncompromised hepatic graft blood inflow. Arterial conduits represent a good solution in cases where conventional revascularisation is not possible. The purpose of this systematic review is to analyse the published evidence on the use of arterial conduits in adult OLT. After review of the Pubmed and EMBASE databases, 19 relevant studies were identified and analysed. Even though patient survival was comparable, most large studies reported worse 1-, 3- and 5-year graft survival rates compared to grafts with standard arterial revascularisation. Primary grafts were more commonly affected than re-grafts. Early and late hepatic artery thrombosis occurred more commonly, while the use of an arterial conduit was identified as an independent risk factor. The overall biliary complications were comparable, however, ischaemic cholangiopathy was encountered about 3 times more in patients with arterial conduits and strongly correlated with the occurrence of late HAT. In conclusion, the use of arterial conduit is a useful option in adult OLT in cases that the conventional revascularisation technique cannot be used or results in suboptimal arterial inflow. More studies directly addressing issues such as pre-operative evaluation regarding the need for arterial conduit, the types of vessels used, positioning of the conduit and post-operative management are required.

De Novo Malignancies After Liver Transplantation With 14 Cases at a Single Center

OBJECTIVE

To analyze the clinical characteristics, risk factors, and prevention of de novo malignant tumors after liver transplantation.

METHODS

Fourteen patients who underwent liver transplantation were identified as having de novo malignancies. The clinical characteristics and survival of these patients were retrospectively reviewed.

RESULTS

Fourteen cases of de novo malignancies after liver transplantation occurred for an incidence rate of 1.94% (14/722), including 11 men (78.6%, mean age, 48 y) and 3 women (21.4%, mean age, 50 y). The mean period from transplantation to cancer diagnosis was 55 ± 35 months. The distribution of tumor histologic types included colon cancer, lung cancer, esophageal cancer, nasopharyngeal cancer, liver cancer, parotid carcinoma, bone cancer, post-transplantation lymphoproliferative disorder, stomach cancer, bladder cancer, and laryngeal cancer. Twelve cases (85.7%) had hepatitis B. Five patients (35.7%) underwent operations, and the other 9 patients underwent chemotherapy or radiotherapy. During a mean follow-up period of 37 ± 26 months after the diagnosis of de novo malignancy, 8 patients (57.1%) died, with only 1 dying of causes not related to the de novo malignancy. The survival analysis showed 1-, 5-, and 7-year survival rates of 85.7%, 71.4%, and 42.9%, respectively.

CONCLUSIONS

De novo malignancies after organ transplantation have been suggested to be a major cause of late mortality. De novo malignancy after orthotopic liver transplantation was found to be related to smoking, sex, and low immune function due to immunosuppressive agents. Solid tumors should be removed, and the patient should receive chemotherapy or radiotherapy as early as possible. Early diagnosis and treatment are very important for improving the prognosis.

Resolution of Hepatic Artery Thrombosis in 2 Pediatric Liver Transplant Patients

Hepatic artery thrombosis (HAT) is a serious complication after liver transplantation. This is the first report of spontaneous resolution of HAT in pediatric liver transplant patients on low molecular weight heparin therapy. A total of 2 patients, a 26-month-old boy who presented with acute liver failure and required emergent liver transplantation and a 15-year-old boy with ulcerative colitis and autoimmune hepatitis-primary sclerosing cholangitis overlap underwent liver transplantation for progressive cirrhosis; both developed HAT during the postoperative period. They were both treated with low molecular weight heparin. Follow-up imaging for both patients showed resolution of HAT without evidence of collateral flow.

Management of early hepatic artery occlusion after liver transplantation with failed rescue

Hepatic artery thrombosis is a serious complication after liver transplantation which often results in biliary complications, early graft loss, and patient death. It is generally thought that early hepatic artery thrombosis without urgent re-vascularization or re-transplantation almost always leads to mortality, especially if the hepatic artery thrombosis occurs within a few days after transplantation. This series presents 3 cases of early hepatic artery thrombosis after living donor liver transplantation, in which surgical or endovascular attempts at arterial re-vascularization failed. Unexpectedly, these 3 patients survived with acceptable graft function after 32 mo, 11 mo, and 4 mo follow-up, respectively. The literatures on factors affecting this devastating complication were reviewed from an anatomical perspective. The collective evidence from survivors indicated that modified nonsurgical management after liver transplantation with failed revascularization may be sufficient to prevent mortality from early hepatic artery occlusion. Re-transplantation may be reserved for selected patients with unrecovered graft function.

Anticoagulation and antiplatelets as prophylaxis for hepatic artery thrombosis after liver transplantation

Hepatic artery thrombosis (HAT) is the most serious vascular complication after liver transplantation. Multiple risk factors have been identified to impact its development. Changes in haemostasis associated with end stage liver disease and the disturbance of the coagulation and anticoagulation cascades play an important role in development of this lethal complication. Early recognition and therapeutic intervention is mandatory to avoid its consequences. Pharmacological prophylaxis, by the use of antiplatelet or anticoagulant agents, is an important tool to reduce its incidence and prevent graft loss. Only a few studies have shown a clear benefit of antiplatelet agents in reducing HAT occurrence, however, these studies are limited by being retrospective and by inhomogeneous populations. The use of anticoagulants such as heparin is associated with an improvement in the outcomes mainly when used for a high-risk patients like living related liver recipients. The major concern when using these agents is the tendency to increase bleeding complications in a setting of already unstable haemostasis. Hence, monitoring of their administration and careful selection of patients to be treated are of great importance. Well-designed clinical studies are still needed to further explore their effects and to formulate proper protocols that can be implemented safely.

Isolated hepatic artery thrombosis leading to multiple liver infarcts in a non-transplant patient

Patient: Female, 62

Final Diagnosis: Hepatic artery thrombosis

Symptoms: Abdominal pain • Nausea • Vomiting

Medication: —

Clinical Procedure: —

Specialty: Surgery

Risk factors associated with early and late HAT after adult liver transplantation

AIM: To identify risk factors that might contribute to hepatic artery thrombosis (HAT) after liver transplantation (LT).

METHODS: The perioperative and follow-up data of a total of 744 liver transplants, performed from February 1999 to July 2010, were retrospectively reviewed. HAT developed in 20 patients (2.7%). HAT was classified as early (occurring in fewer than 30 d post LT) or late (occurring more than 30 d post LT). Early HAT developed in 14 patients (1.9%). Late HAT developed in 6 patients (0.8%). Risk factors associated with HAT were analysed using the χ² test for univariate analysis and logistic regression for multivariate analysis.

RESULTS: Lack of ABO compatibility, recipient/donor weight ratio ≥ 1.15, complex arterial reconstruction, duration time of hepatic artery anastomosis > 80 min, duration time of operation > 10 h, dual grafts, number of units of blood received intraoperatively ≥ 7, number of units of fresh frozen plasma (FFP) received intraoperatively ≥ 6, postoperative blood transfusion and postoperative FFP use were significantly associated with early HAT in the univariate analysis (P < 0.1). After logistic regression, independent risk factors associated with early HAT were recipient/donor weight ratio ≥ 1.15 (OR = 4.499), duration of hepatic artery anastomosis > 80 min (OR = 5.429), number of units of blood received intraoperatively ≥ 7 (OR = 4.059) and postoperative blood transfusion (OR = 6.898). Graft type (whole/living-donor/split), duration of operation > 10 h, retransplantation, rejection reaction, recipients with diabetes preoperatively and recipients with a high level of blood glucose or diabetes postoperatively were significantly associated with late HAT in the univariate analysis (P < 0.1). After logistic regression, the independent risk factors associated with early HAT were duration of operation > 10 h (OR = 6.394), retransplantation (OR = 21.793) and rejection reactions (OR = 16.936).

CONCLUSION: Early detection of these risk factors, strict surveillance protocols by Doppler ultrasound and prophylactic anticoagulation for recipients at risk might be determined prospectively.

Management of cytomegalovirus infection and disease in liver transplant recipients

Cytomegalovirus (CMV) is one of the most common viral pathogens causing clinical disease in liver transplant recipients, and contributing to substantial morbidity and occasional mortality. CMV causes febrile illness often accompanied by bone marrow suppression, and in some cases, invades tissues including the transplanted liver allograft. In addition, CMV has been significantly associated with an increased predisposition to acute and chronic allograft rejection, accelerated hepatitis C recurrence, and other opportunistic infections, as well as reduced overall patient and allograft survival. To negate the adverse effects of CMV infection on transplant outcome, its prevention, whether through antiviral prophylaxis or preemptive therapy, is an essential component to the management of liver transplant recipients. Two recently updated guidelines have suggested that antiviral prophylaxis or preemptive therapy are similarly effective in preventing CMV disease in modest-risk CMV-seropositive liver transplant recipients, while antiviral prophylaxis is the preferred strategy over preemptive therapy for the prevention of CMV disease in high-risk recipients [CMV-seronegative recipients of liver allografts from CMV-seropositive donors (D+/R-)]. However, antiviral prophylaxis has only delayed the onset of CMV disease in many CMV D+/R- liver transplant recipients, and such occurrence of late-onset CMV disease was significantly associated with increased all-cause and infection-related mortality after liver transplantation. Therefore, a search for better strategies for prevention, such as prolonged duration of antiviral prophylaxis, a hybrid approach (antiviral prophylaxis followed by preemptive therapy), or the use of immunologic measures to guide antiviral prophylaxis has been suggested to prevent late-onset CMV disease. The standard treatment of CMV disease consists of intravenous ganciclovir or oral valganciclovir, and if feasible, reduction in pharmacologic immunosuppression. In one clinical trial, oral valganciclovir was as effective as intravenous ganciclovir for the treatment of mild to moderate CMV disease in solid organ (including liver) transplant recipients. The aim of this article is to provide a state-of-the art review of the epidemiology, diagnosis, prevention, and treatment of CMV infection and disease after liver transplantation.

Etiology and management of hepatic artery thrombosis after adult liver transplantation

Hepatic artery thrombosis (HAT) represents a major cause of graft loss and mortality after liver transplantation. It occurs in up to 9% of adult recipients. The early diagnosis of HAT decreases septic complications, multiorgan failure, and graft loss, and there are better outcomes after treatment. In this study, we reviewed 102 episodes of HAT, which were classified as early hepatic artery thrombosis (E-HAT) when they were diagnosed within the first 21 days after transplantation. The overall incidence of HAT was 7%: 31 episodes (30.4%) were identified as E-HAT, and 71 episodes (69.6%) were identified as late hepatic artery thrombosis (L-HAT). Graft dysfunction was the commonest presentation (30 cases or 29%). Most E-HAT cases were managed with retransplantation (74%), whereas early revascularization was carried out for only 13% with a 75% success rate. The incidence of retransplantation for L-HAT was only 41%, whereas 32% were too ill for relisting and eventually died. Successful conservative management was noted for 13 of the 102 patients (13%) with collateralization and good hepatic perfusion, with biliary complications encountered in 7 cases (54%) subsequently. A multivariate analysis showed that previous episodes of HAT, the number of arterial anastomoses, and a low donor weight were independent risk factors for E-HAT, whereas a history of upper abdominal operations (non-HAT), a previous history of HAT, a low donor weight, and a recipient age < 50 years were independent risk factors for L-HAT. The graft survival rates for HAT patients were 52%, 36.6%, and 27.4% at 1, 3, and 5 years, whereas the corresponding rates were 81.4%, 81.2%, and 76.4% for non-HAT patients. In conclusion, prompt revascularization for E-HAT patients decreases the incidence of serious, irreversible septic complications and graft loss and improves overall outcomes. A significant number of L-HAT patients do not require further intervention despite the high incidence of ischemic cholangiopathy.