The role of hypercoagulability in liver fibrogenesis

Anticoagulation for stroke prevention in atrial fibrillation and treatment of venous thromboembolism and portal vein thrombosis in cirrhosis: guidance from the SSC of the ISTH

While advanced liver disease was previously considered to be an acquired bleeding disorder, there is increasing recognition of an associated prothrombotic state with patients being at higher risk of atrial fibrillation (AF) and stroke and venous thromboembolism (VTE) including portal vein thrombosis (PVT). We review the available literature on epidemiology, pathophysiology, and risk factors and provide guidance on anticoagulant management of these conditions in adults with cirrhosis. In patients with Child-Pugh A or B cirrhosis and AF, we recommend anticoagulation with standard-dose direct oral anticoagulants (DOACs) in accordance with cardiology guideline recommendations for patients without liver disease. In those with Child-Pugh C cirrhosis, there is inadequate evidence with respect to the benefit and risk of anticoagulation for stroke prevention in AF. In patients with cirrhosis and acute deep vein thrombosis or pulmonary embolism, we recommend anticoagulation and suggest use of either a DOAC or low-molecular-weight heparin (LMWH)/vitamin K antagonist (VKA) in Child-Pugh A or B cirrhosis and LMWH alone (or as a bridge to VKA in patients with a normal baseline international normalized ratio) in Child-Pugh C cirrhosis. We recommend anticoagulation for patients with cirrhosis and symptomatic PVT. We suggest anticoagulation for those with asymptomatic, progressing PVT and recommend continuing extended anticoagulation for liver transplant candidates with PVT.

Anticoagulation against portal vein thrombosis reduces mortality and liver cirrhosis-related complications: A propensity score-matched study

AIM

Portal vein thrombosis (PVT) is one of the common complications of liver cirrhosis. Although anticoagulation contributes to thrombus resolution and is considered the first-choice treatment, its impact on patients' prognosis is still controversial. This study aimed to clarify the benefit of anticoagulation on mortality, liver function, and the incidence of liver cirrhosis-related complications in cirrhotic PVT patients.

METHODS

We conducted a multicenter retrospective review in which we included 78 eligible patients with PVT out of 439. After propensity score matching, 21 cirrhotic PVT patients were included in each one of the untreated control and anticoagulation groups.

RESULTS

Overall survival was significantly improved in the anticoagulation group compared with the control group (p = 0.041), along with PVT size reduction (53.3% vs. 108.2%, p = 0.009). At the time of CT follow-up, the anticoagulation group showed a lower ALBI score (p = 0.037) and its prevalence of massive ascites was significantly lower (p = 0.043) compared with the control group. The incidence of overt encephalopathy was also lower in the anticoagulation group (p = 0.041). The cumulative incidence of bleeding events did not differ significantly between the two groups.

CONCLUSIONS

Anticoagulation improves the survival of patients with cirrhotic PVT. Preserved liver function and reduced risks of cirrhosis-related complications under the treatment may have contributed to a better prognosis. Given its efficacy and safety, anticoagulation is worth initiating in patients with PVT.

Potential utility of a multi-component coagulation factor panel to calculate MELD scores and assess the risk of portal vein thrombosis in chronic liver disease

BACKGROUND

Current quantitative approaches to assess chronic liver disease (CLD) severity have limitations. Further, portal vein thrombosis (PVT) pre-liver transplant (LT) is a major contributor to morbidity in CLD; the means of detecting and/or predicting PVT are limited. We sought to explore whether plasma coagulation factor activity levels can serve as a substitute for prothrombin time/international normalized ratio (PT/INR) in the Model for End-stage Liver Disease (MELD), and/or help assess the risk of PVT.

METHODS

Plasma activity levels of Factor V (FV), Factor VIII (FVIII), Protein C (PC), and Protein S (PS) and the concentrations of D-dimer, sP-selectin, and asTF were assessed in two cohorts of CLD patients (ambulatory, n = 42; LT, n = 43).

RESULTS

FV and PC activity levels strongly correlated with MELD scores, which enabled the development of a novel scoring system based on multiple linear regressions of the correlations of FV and PC activity with MELD-Na that substitutes PT/INR. Six-month and 1-year follow-up revealed that our novel approach was non-inferior to MELD-Na at predicting mortality. A significant inverse correlation between FVIII activity levels and PVT was found in the LT cohort (p = 0.010); FV and PS activity levels were in-trend (p = 0.069, p = 0.064). We developed a logistic regression-based compensation score to identify patients at risk of PVT.

CONCLUSIONS

We demonstrate that FV and PC activity levels may be used to replace PT/INR in MELD scoring. We also show the potential of using the combination of FV, FVIII, and PS activity levels to assess the risk of PVT in CLD.

Machine learning predicts portal vein thrombosis after splenectomy in patients with portal hypertension: Comparative analysis of three practical models

BACKGROUND

For patients with portal hypertension (PH), portal vein thrombosis (PVT) is a fatal complication after splenectomy. Postoperative platelet elevation is considered the foremost reason for PVT. However, the value of postoperative platelet elevation rate (PPER) in predicting PVT has never been studied.

AIM

To investigate the predictive value of PPER for PVT and establish PPER-based prediction models to early identify individuals at high risk of PVT after splenectomy.

METHODS

We retrospectively reviewed 483 patients with PH related to hepatitis B virus who underwent splenectomy between July 2011 and September 2018, and they were randomized into either a training (n = 338) or a validation (n = 145) cohort. The generalized linear (GL) method, least absolute shrinkage and selection operator (LASSO), and random forest (RF) were used to construct models. The receiver operating characteristic curves (ROC), calibration curve, decision curve analysis (DCA), and clinical impact curve (CIC) were used to evaluate the robustness and clinical practicability of the GL model (GLM), LASSO model (LSM), and RF model (RFM).

RESULTS

Multivariate analysis exhibited that the first and third days for PPER (PPER1, PPER3) were strongly associated with PVT [odds ratio (OR): 1.78, 95% confidence interval (CI): 1.24-2.62, P = 0.002; OR: 1.43, 95%CI: 1.16-1.77, P < 0.001, respectively]. The areas under the ROC curves of the GLM, LSM, and RFM in the training cohort were 0.83 (95%CI: 0.79-0.88), 0.84 (95%CI: 0.79-0.88), and 0.84 (95%CI: 0.79-0.88), respectively; and were 0.77 (95%CI: 0.69-0.85), 0.83 (95%CI: 0.76-0.90), and 0.78 (95%CI: 0.70-0.85) in the validation cohort, respectively. The calibration curves showed satisfactory agreement between prediction by models and actual observation. DCA and CIC indicated that all models conferred high clinical net benefits.

CONCLUSION

PPER1 and PPER3 are effective indicators for postoperative prediction of PVT. We have successfully developed PPER-based practical models to accurately predict PVT, which would conveniently help clinicians rapidly differentiate individuals at high risk of PVT, and thus guide the adoption of timely interventions.

Investigational drugs in early clinical development for portal hypertension

INTRODUCTION

Advanced chronic liver disease is considered a reversible condition after removal of the primary aetiological factor. This has led to a paradigm shift in which portal hypertension (PH) is a reversible complication of cirrhosis. The pharmacologic management of PH is centered on finding targets to modify the natural history of cirrhosis and PH.

AREAS COVERED

This paper offers an overview of the use of pharmacological strategies in early clinical development that modify PH. Papers included were selected from searching clinical trials sites and PubMed from the last 10 years.

EXPERT OPINION

A paradigm shift has generated a new concept of PH in cirrhosis as a reversible complication of a potentially curable disease. Decreasing portal pressure to prevent decompensation and further complications of cirrhosis that may lead liver transplantation or death is a goal. Therapeutic strategies also aspire achieve total or partial regression of fibrosis thus eliminating the need for treatment or screening of PH.

Predictors of portal vein thrombosis after laparoscopic splenectomy and azygoportal disconnection in hepatitis B cirrhosis: a prospective study

BACKGROUND

The thrombosis of the main and intrahepatic branches of the portal vein (TMIP) is potentially lethal and deemed a common complication following laparoscopic splenectomy and azygoportal disconnection (LSD) in patients with cirrhosis and portal hypertension (PH). The predictors of TMIP after LSD remain unclear. The aim of this prospective study was to explore the predictive and risk factors for TMIP after LSD in cirrhotic patients with PH caused only by hepatitis B virus.

METHODS

From September 2014 to March 2017, we enrolled 115 patients with hepatitis B cirrhosis and PH who successfully underwent LSD. Patients were subdivided into a TMIP group and a non-TMIP group. Univariate and multivariate logistic regression analysis was conducted on 24 items of demographic and preoperative data, to explore the risk factors of TMIP.

RESULTS

Twenty-nine (25.22%) patients developed TMIP on postoperative day (POD) 7 and 26 (22.81%) patients developed TMIP on POD 30. From POD 7 to POD 30, 12 patients who did not have TMIP at POD 7 were newly diagnosed with TMIP, with portal vein diameter 15.05 ± 2.58 mm. Another 14 patients in whom TMIP had resolved had portal vein diameter 14.02 ± 1.76 mm. Univariate analysis and multivariate logistic regression revealed that portal vein diameter ≥ 13 mm [relative risk (RR) 5.533, 95% confidence interval (CI) 1.222-25.042; P = 0.026] and portal vein diameter ≥ 15 mm (RR 3.636, 95% CI 1.466-9.021; P = 0.005) were significant independent risk factors for TMIP on POD 7 and 30, respectively.

CONCLUSION

Portal vein diameter ≥ 13 mm and ≥ 15 mm were significant independent predictors for TMIP after LSD in patients with hepatitis B cirrhosis and PH on POD 7 and POD 30, respectively.

TRIAL REGISTRATION

We registered our research at https://www.

CLINICALTRIALS

gov/ . The name of research registered is "Warfarin Prevents Portal Vein Thrombosis in Patients After Laparoscopic Splenectomy and Azygoportal Disconnection." The trial registration identifier at clinicaltrials.gov is NCT02247414.

Pulmonary Arterial Hypertension and Consecutive Right Heart Failure Lead to Liver Fibrosis

Hepatic congestion occurs in patients with right heart failure and can ultimately lead to liver fibrosis or cardiac cirrhosis. Elevated pulmonary arterial pressure is found in patients with hepatic congestion. However, whether pulmonary arterial hypertension (PAH) can be a cause of liver fibrosis is unknown. The aim of this study was to investigate whether rats in the SuHx model with severe PAH develop liver fibrosis and to explore the mechanisms of congestive hepatic fibrosis both in rats and humans. To achieve this, PAH was induced in six to eight-week old male Sprague Dawley rats by a single subcutaneous injection of the VEGFR 2 inhibitor SU5416 and subsequent hypoxia for 3 weeks, followed by a 6-week period in room air. SuHx-exposed rats developed severe PAH, right ventricular hypertrophy (RVH), and consecutive right ventricular failure. Cardiac magnetic resonance imaging (MRI) and histological analysis revealed that PAH rats developed both hepatic congestion and liver fibrosis. Gene set enrichment analysis (GSEA) of whole liver RNA sequencing data identified a hepatic stellate cell specific gene signature in PAH rats. Consistently, tissue microarray from liver of patients with histological evidence of hepatic congestion and underlying heart disease revealed similar fibrogenic gene expression patterns and signaling pathways. In conclusion, severe PAH with concomitant right heart failure leads to hepatic congestion and liver fibrosis in the SU5416/hypoxia rat PAH model. Patients with PAH should therefore be screened for unrecognized liver fibrosis.

Effects of Salvia hispanica L. (chia) seed on blood coagulation, endothelial dysfunction and liver fibrosis in an experimental model of Metabolic Syndrome

The aim of this study was to analyze blood coagulation, endothelial dysfunction and liver fibrosis in an experimental model of Metabolic Syndrome (MS) induced by chronic administration of a sucrose-rich diet (SRD) and to evaluate the effects of chia seed as a therapeutic strategy. Male Wistar rats were fed with a reference diet (RD) - 6 months - or a SRD - 3 months. Then, the last group was randomly divided into two subgroups. One subgroup continued receiving the SRD for up to 6 months and the other was fed with a SRD where whole chia seed was incorporated as the source of dietary fat for the next 3 months (SRD + CHIA). Results showed that rats fed a SRD for a long period of time develop dyslipidemia, visceral adiposity, insulin resistance, and a hypercoagulable and hypofibrinolytic basal state. Hepatic VCAM-1 (main adhesion molecules involved in endothelial dysfunction) expression was significantly increased. In addition, the SRD group presented hepatic steatosis, a significant increase in interstitial collagen deposition and hydroxyproline content. Liver TGF-β1 (a key cytokine involved in fibrogenesis) levels increased and a negative correlation with PPARα protein mass levels was found. The administration of chia seed for 3 months reversed dyslipidemia, visceral adiposity and insulin resistance. Platelet count, coagulation parameters and plasma fibrinogen levels were normalized. In the liver tissue, VCAM-1 expression, steatosis, interstitial collagen deposition and the hydroxyproline content decreased. TGF-β1 expression was decreased and this was associated with an increase in the PPARα protein levels. The present study showed new aspects in the progression from liver steatosis to fibrosis in dyslipidemic insulin-resistant rats chronically fed a sucrose-rich diet. Chia seed supplementation could be used as a functional food and a potential dietary strategy to prevent or ameliorate disorders related to atherothrombotic cardiovascular events and NASH.

Non-contrast enhanced magnetic resonance imaging for characterization of Fontan associated liver disease

OBJECTIVES

To evaluate the ability of non-contrast enhanced magnetic resonance imaging (MRI) techniques to characterize Fontan associated liver disease (FALD) in adolescent and adult Fontan patients.

METHODS

Fontan patients (n = 29) and healthy controls (n = 13) underwent an MRI protocol with T₁, T₂ and Apparent Diffusion Coefficient (ADC) mapping. Routine FALD screening included abdominal ultrasound and laboratory testing.

RESULTS

Median follow-up after Fontan operation was 15.1 (IQR 12.0-16.8) years. Distinct differences in tissue characteristics were visualized. T₁ and T₂ relaxation times were prolonged in Fontan patients, particularly of the right lobe (T₁: 745 (IQR 715-784) ms vs. 586 (IQR 555-602) ms, p < 0.001; T₂: 63 (IQR 59-64) ms vs. 58 (IQR 56-60) ms, p = 0.002). Left lobe ADC was lower in Fontan patients (1.10 (IQR 1.06-1.18) x 10^-3 mm²/s vs. 1.23 (IQR 1.19-1.29) x 10^-3 mm²/s, p < 0.001). T₂ mapping was able to differentiate between controls and Fontan patients with different FALD severity. Right lobe T₂ was higher in patients with moderate or severe in comparison to those with no or mild changes and healthy controls (64 (IQR 61-67) ms vs. 60 (IQR 59-63) ms vs. 58 (IQR 56-60) ms, p = 0.001).

CONCLUSIONS

Non-contrast enhanced MRI methods are able to visualize regional differences in liver tissue characteristics. T₁ and T₂ relaxation times were prolonged in Fontan patients suggestive of fibrosis or congestive hepatopathy, while reduced ADC might reflect impaired microperfusion. These methods have promising clinical potential for detection of liver abnormalities in Fontan patients. The usefulness of T₂ mapping to grade FALD severity merits further investigation.

Resistance to thrombomodulin correlates with liver stiffness in chronic liver disease a prospective single-center cohort study

INTRODUCTION

Chronic liver disease (CLD) is characterized by changes in haemostasis, embracing both hypo- and hypercoagulability. Global hemostatic tests such as thrombin generation assays evaluate the hemostatic balance, to better assess bleeding and thrombotic risks. In addition, procoagulant state in patients with CLD has been demonstrated using modified thrombin generation assays with thrombomodulin, a cofactor for protein C activation. In this study, we prospectively determined thrombin generation and thrombomodulin resistance in patients with CLD staged with liver stiffness measurement (LSM), using both the fully automated analyzer ST Genesia® Thrombin Generation System (STG) and the calibrated automated thrombogram assay (CAT).

MATERIALS AND METHODS

Demographic, clinical and laboratory characteristics, and blood samples were collected from 65 patients with CLD. Liver stiffness was measured by transient elastography, and thrombin generation and thrombomodulin resistance, by STG and CAT.

RESULTS

Patients were separated based on LSM of <21 and ≥21 kilopascals (kPa). The propagation rate of thrombin generation was higher in patients with LSM ≥21 kPa and the thrombin generation rate increased as LSM increased. In addition, thrombomodulin resistance assessed by STG and CAT was higher in patients with LSM ≥21 kPa. However, ETP inhibition by activated protein C was comparable in patients with LSM <21 and ≥21 kPa. Finally, LSM correlated with most thrombin generation parameters.

CONCLUSION

The STG automated system may have value in the assessment of patients with chronic liver disease in the routine coagulation laboratory. LSM ≥21 kPa identify a procoagulant phenotype in these patients, including thrombomodulin resistance.

Usage of Direct Acting Oral Anticoagulants in Cirrhotic and Non-Cirrhotic Portal Vein Thrombosis: A Systematic Review

Thrombosis of the portal vein (PVT) is generally seen in the setting of liver cirrhosis and to a lesser extent in the absence of cirrhosis. There is no clear guidance in relation to approaching treatment with anticoagulation in this condition. The professional societies and guidelines recommend treatment with traditional anticoagulation like low-molecular-weight heparin and vitamin-K antagonists in patients presenting with acute portal vein thrombosis. There is no clarity in relation to treatment in the setting of chronic PVT and in patients with cirrhosis. Also, the role of direct-acting oral anticoagulants (DOACs) that are becoming a preferred choice for anticoagulation for various other indications is not clear in the case of PVT. There are a very few studies in the medical literature that have investigated the role of DOACs in patients with PVT in different settings. Thus, we performed a systematic review of the literature to study the use of DOACs in PVT in patients with and without cirrhosis. The results of the available studies show that DOACS appears to be a promising choice for the treatment of patients with PVT. The availability of more data in the future along with better availability of the approved reversal agents for various DOACs is expected to make DOACS a preferred choice for the clinicians to treat patients with PVT.

Exploring the Complex Role of Coagulation Factor VIII in Chronic Liver Disease

Chronic liver disease is one of the leading causes of death in the United States. Coagulopathy is often a sequela of chronic liver disease, however, the role and regulation of coagulation components in chronic liver injury remain poorly understood. Clinical and experimental evidence indicate that misexpression of the procoagulant factor VIII (FVIII) is associated with chronic liver disease. Nevertheless, the molecular mechanism of FVIII-induced chronic liver injury progression remains unknown. This review provides evidence supporting a pathologic role for FVIII in the development of chronic liver disease using both experimental and clinical models.

Lenvatinib prevents liver fibrosis by inhibiting hepatic stellate cell activation and sinusoidal capillarization in experimental liver fibrosis

Molecular targeted agents are pharmacologically used to treat liver fibrosis and have gained increased attention. The present study examined the preventive effect of lenvatinib on experimental liver fibrosis and sinusoidal capillarization as well as the in vitro phenotypes of hepatic stellate cells. LX-2, a human stellate cell line, was used for in vitro studies. In vivo liver fibrosis was induced in F344 rats using carbon tetrachloride by intraperitoneal injection for 8 weeks, and oral administration of lenvatinib was started two weeks after initial injection of carbon tetrachloride. Lenvatinib restrained proliferation and promoted apoptosis of LX-2 with suppressed phosphorylation of extracellular signal-regulated kinase 1/2 and AKT. It also down-regulated COL1A1, ACTA2 and TGFB1 expressions by inhibiting the transforming growth factor-β1/Smad2/3 pathway. Treatment with lenvatinib also suppressed platelet-derived growth factor-BB-stimulated proliferation, chemotaxis and vascular endothelial growth factor-A production, as well as basic fibroblast growth factor-induced LX-2 proliferation. In vivo study showed that lenvatinib attenuated liver fibrosis development with reduction in activated hepatic stellate cells and mRNA expression of profibrogenic markers. Intrahepatic neovascularization was ameliorated with reduced hepatic expressions of Vegf1, Vegf2 and Vegfa in lenvatinib-treated rats. Collectively, these results suggest the potential use of lenvatinib as a novel therapeutic strategy for liver fibrosis.

COVID-19 With Preexisting Hypercoagulability Digestive Disease

The outbreak of coronavirus disease of 2019 (COVID-19) has become a global public health and economic crisis. The advent of hypercoagulability and thrombotic complications can substantially influence the prognosis of COVID-19 patients. In this review, we elaborate on the clinical findings, potential underlying pathogenesis, and therapeutic strategy of hypercoagulability and thromboembolism in COVID-19, particularly focusing on the COVID-19 patients with preexisting digestive hypercoagulability disease.

Mortality and Hepatic Decompensation in Patients With Cirrhosis and Atrial Fibrillation Treated With Anticoagulation

BACKGROUND AND AIMS

Outcomes with anticoagulation (AC) are understudied in advanced liver disease. We investigated effects of AC with warfarin and direct oral anticoagulants (DOACs) on all-cause mortality and hepatic decompensation as well as ischemic stroke, major adverse cardiovascular events, splanchnic vein thrombosis, and bleeding in a cohort with cirrhosis and atrial fibrillation (AF).

APPROACH AND RESULTS

This was a retrospective, longitudinal study using national data of U.S. veterans with cirrhosis at 128 medical centers, including patients with cirrhosis with incident AF, from January 1, 2012 to December 31, 2017 followed through December 31, 2018. To assess the effects of AC on outcomes, we applied propensity score (PS) matching and marginal structural models (MSMs) to account for confounding by indication and time-dependent confounding. The final cohort included 2,694 veterans with cirrhosis with AF (n = 1,694 and n = 704 in the warfarin and DOAC cohorts after PS matching, respectively) with a median of 4.6 years of follow-up. All-cause mortality was lower with warfarin versus no AC (PS matched: hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.55-0.76; MSM models: HR, 0.54; 95% CI, 0.40-0.73) and DOACs versus no AC (PS matched: HR, 0.68; 95% CI, 0.50-0.93; MSM models: HR, 0.50; 95% CI, 0.31-0.81). In MSM models, warfarin (HR, 0.29; 95% CI, 0.09-0.90) and DOACs (HR, 0.23; 95% CI, 0.07-0.79) were associated with reduced ischemic stroke. In secondary analyses, bleeding was lower with DOACs compared to warfarin (HR, 0.49; 95% CI, 0.26-0.94).

CONCLUSIONS

Warfarin and DOACs were associated with reduced all-cause mortality. Warfarin was associated with more bleeding compared to no AC. DOACs had a lower incidence of bleeding compared to warfarin in exploratory analyses. Future studies should prospectively investigate these observed associations.

Healing gone wrong: convergence of hemostatic pathways and liver fibrosis?

Fibrosis results from a disordered wound healing response within the liver with activated hepatic stellate cells laying down dense, collagen-rich extracellular matrix that eventually restricts liver hepatic synthetic function and causes increased sinusoidal resistance. The end result of progressive fibrosis, cirrhosis, is associated with significant morbidity and mortality as well as tremendous economic burden. Fibrosis can be conceptualized as an aberrant wound healing response analogous to a chronic ankle sprain that is driven by chronic liver injury commonly over decades. Two unique aspects of hepatic fibrosis - the chronic nature of insult required and the liver's unique ability to regenerate - give an opportunity for pharmacologic intervention to stop or slow the pace of fibrosis in patients early in the course of their liver disease. Two potential biologic mechanisms link together hemostasis and fibrosis: focal parenchymal extinction and direct stellate cell activation by thrombin and Factor Xa. Available translational research further supports the role of thrombosis in fibrosis. In this review, we will summarize what is known about the convergence of hemostatic changes and hepatic fibrosis in chronic liver disease and present current preclinical and clinical data exploring the relationship between the two. We will also present clinical trial data that underscores the potential use of anticoagulant therapy as an antifibrotic factor in liver disease.

Nonalcoholic Fatty Liver Disease-Evidence for a Thrombophilic State?

Nonalcoholic fatty liver disease is the leading cause of liver disease worldwide. It has expansive extrahepatic morbidity and mortality including increased rates of both cardiovascular disease and venous thromboembolism. Derangements in primary, secondary and tertiary hemostasis are found in nonalcoholic fatty liver disease independent of those ascribed to end-stage liver disease. The abnormalities across all stages of hemostasis explain the increased rates of clinically relevant thrombotic events, including pulmonary embolism, deep vein thrombosis and portal vein thrombosis, which on an epidemiologic basis appears to be independent of obesity and other traditional venous thromboembolic risk factors. However, given the complex interaction between obesity, body composition and nonalcoholic fatty liver disease and the potential for exercise to benefit all three, more research is needed to further define the role of each in contributing to the prohemostatic state of nonalcoholic fatty liver disease in order to improve patient oriented outcomes.

Imaging of Fontan-associated liver disease

The Fontan operation has dramatically altered the natural history of functionally single ventricle congenital heart disease. Patients who have undergone the Fontan operation are living longer and, thus, noncardiac morbidity resulting from the Fontan operation is increasingly being recognized. Fontan-associated liver disease (FALD), one of the chief morbidities following the Fontan operation, is believed to be a multifactorial process that manifests as hepatic congestion and fibrosis, portal hypertension, and development of focal liver lesions, including malignant tumors. This article reviews the imaging findings of FALD in the pediatric and young adult population, reviews the literature related to the imaging of FALD and discusses possible screening algorithms for this population. The need for further research to better understand the causes of FALD, to establish if early liver stiffness measurements (or their change over time) predict long-term outcomes and complications, and to define optimal liver screening procedures is highlighted.

Liver fibrosis is driven by protease-activated receptor-1 expressed by hepatic stellate cells in experimental chronic liver injury

BACKGROUND

Blood coagulation protease activity is proposed to drive hepatic fibrosis through activation of protease-activated receptors (PARs). Whole-body PAR-1 deficiency reduces experimental hepatic fibrosis, and in vitro studies suggest a potential contribution by PAR-1 expressed by hepatic stellate cells. However, owing to a lack of specific tools, the cell-specific role of PAR-1 in experimental hepatic fibrosis has never been formally investigated. Using a novel mouse expressing a conditional PAR-1 allele, we tested the hypothesis that PAR-1 expressed by hepatic stellate cells contributes to hepatic fibrosis.

METHODS

PAR-1flox/flox mice were crossed with mice expressing Cre recombinase controlled by the lecithin retinol acyltransferase (LRAT) promoter, which induces recombination in hepatic stellate cells. Male PAR-1flox/flox/LRATCre and PAR-1flox/flox mice were challenged twice weekly with carbon tetrachloride (CCl4, 1 mL/kg i.p.) for 6 weeks to induce liver fibrosis.

RESULTS

PAR-1 mRNA levels were reduced (>95%) in hepatic stellate cells isolated from PAR-1flox/flox/LRATCre mice. Hepatic stellate cell activation was evident in CCl4-challenged PAR-1flox/flox mice, indicated by increased α-smooth muscle actin labeling and induction of several profibrogenic genes. CCl4-challenged PAR-1flox/flox mice displayed robust hepatic collagen deposition, indicated by picrosirius red staining and type I collagen immunolabeling. Notably, stellate cell activation and collagen deposition were significantly reduced (>30%) in PAR-1flox/flox/LRATCre mice. Importantly, the reduction in liver fibrosis was not a consequence of reduced acute CCl4 hepatotoxicity in PAR-1flox/flox/LRATCre mice.

CONCLUSIONS

The results constitute the first direct experimental evidence that PAR-1 expressed by stellate cells directly promotes their profibrogenic phenotype and hepatic fibrosis in vivo.

Platelet C-Type Lectin-Like Receptor 2 Reduces Cholestatic Liver Injury in Mice

Cholestatic liver injury leads to liver dysfunction. The available evidence suggests that platelets can either promote or reduce liver injury and fibrosis. This study focused on the functions of the C-type lectin-like receptor 2 (CLEC-2), a new special platelet receptor that binds with podoplanin-activating platelets. The role of CLEC-2 and podoplanin in cholestatic liver injury was investigated. Mice were injected intraperitoneally with weekly doses of anti-CLEC-2 antibody (2A2B10) to achieve effective CLEC-2 inhibition in their platelets. Next, left and middle hepatic bile duct ligation (BDL) procedures were performed, and mice were euthanized 1 week later (2A2B10-BDL group). In addition, mice were prepared for control groups, and relevant histological and laboratory variables were compared among these groups. The inhibition of CLEC-2 resulted in increasing hepatocellular necrosis, hepatic inflammation, and liver fibrosis. In addition, podoplanin was strongly expressed in hepatic sinusoidal endothelial cells in BDL-treated mice. Moreover, in 2A2B10-BDL mice, total plasma bile acid levels were significantly increased. In summary, podoplanin is expressed on hepatic sinusoidal endothelial cells upon BDL. Platelets bind with podoplanin via CLEC-2 and become activated. As a result, the total bile acid pool is decreased. Therefore, the CLEC-2-podoplanin interaction promotes liver protection and inhibits liver fibrosis after cholestatic liver injury.

Silencing of tissue factor by antisense deoxyoligonucleotide mitigates thioacetamide-induced liver injury

BACKGROUND

Retinoid receptors (RRs), RAR-α and RXR-α, work as transcription factors that regulate cell growth, differentiation, survival, and death. Hepatic stellate cells (HSCs) store retinoid and release its RRs as lipid droplets upon their activation.

PURPOSE

We test the hypothesis that loss of retinoid receptors RAR-α and RXR-α from HSCs is dependent on tissue factor (TF) during thioacetamide (TAA)-induced liver injury.

METHODS

Liver toxicity markers, TF, fibrin, cleaved caspase-3, and cyclin D1 as well as histopathology were investigated.

RESULTS

Increased TF, fibrin, cleaved caspase-3, and cyclin D1 protein expression is seen in zone of central vein after TAA injection compared with vehicle-treated mice. A strong downregulation of RAR-α and RXR-α is seen in TAA-induced liver injury. In addition, histopathological obliteration and pericentral expression of cleaved caspase 3 and cyclin D1 are observed after TAA injection compared with the normal vehicle-treated mice. No changes have been seen in TAA/TF-sense (SC) in whole parameters compared with TAA-treated animals. TAA/TF-antisense (AS)-treated mice show normal expression of all parameters and normal histopathological features when compared with the control mice. In conclusion, this study declares that the strong downregulation of RAR-α and RXR-α may cause liver injury and particularly activation of HSCs in TAA-induced toxicity. TF-AS treatment not only downregulates TF protein expression but also alleviates loss of liver RAR-α and RXR-α and suppresses the activated apoptosis signals in TAA-induced liver toxicity. Finally, TF and RAR-α/RXR-α are important regulatory molecules in TAA induced acute liver injury.

Role of ncRNAs in modulation of liver fibrosis by extracellular vesicles

Extracellular vesicles (EVs) are small membrane vesicles carrying bioactive lipids, proteins and nucleic acids of the cell of origin. In particular, EVs carry non-coding RNAs (ncRNAs) and the vesicle membrane may protect them from degradation. Once released within the extracellular space, EVs can transfer their cargo, including ncRNAs, to neighboring or distant cells, thus inducing phenotypical and functional changes that may be relevant in several physio-pathological conditions. This review provides an overview of the role of EV-carried ncRNAs in the modulation of liver fibrosis. In particular, we focused on EV-associated microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) involved into the development of liver fibrosis and on the potential use of EV-associated ncRNAs as diagnostic and prognostic biomarkers of liver fibrosis.

Thromboembolic Events Are Independently Associated with Liver Stiffness in Patients with Fontan Circulation

Background: Thromboembolism (TE) and Fontan-associated liver disease (FALD) are common and lead to significant morbidity in Fontan circulations. Risk factors for TE and the potential link between TE and FALD are not well understood. The objective of this study was to evaluate the association between TE and the severity of FALD based on radiologic liver stiffness. Methods: Using a retrospective cohort study design, 85 Fontan patients (aged 27.7 ± 8.2 years) who had liver stiffness measurement were included. Multivariable logistic regression was used to determine independent associations with TE. Results: Sixteen patients (19%) had a history of TE after the Fontan procedure at a mean age of 21.4 ± 15.0 years. Patients with TE were significantly older at the time of the last evaluation (33.8 ± 11.7 vs. 26.3 ± 6.5 years, p = 0.03). Liver stiffness by MRI and ultrasound was higher in the TE group (5.1 ± 1.4 vs. 4.3 ± 1.2 kPa, p = 0.04 and 2.8 ± 0.4 vs. 2.4 ± 0.5 m/s, p = 0.04, respectively). On multivariable analysis, higher liver stiffness (odds ratio (OR): 2.12, p = 0.03) and older age (OR: 1.11, p = 0.03) were associated with TE. Conclusions: This study found an association between TE, age, and radiologic liver stiffness.

Anticoagulation in Patients with Liver Cirrhosis (Literature Review)

Liver cirrhosis is accompanied by complex hemostatic disorders with an increase in the risk of both hemorrhagic and thrombotic complications. Reduced coagulation protein synthesis, such as factors II, VII, IX, X and thrombocytopenia are associated with an increased risk of bleeding. Reducing the synthesis of such anticoagulants as protein C, protein S, antithrombin III is accompanied by increased generation of thrombin, which leads to procoagulant status, increased risk of venous thrombosis, pulmonary embolism, and portal vein thrombosis. Activation of the coagulation cascade increases the risk of thrombosis, and also plays an important role in liver damage, contributing to the progression of fibrosis. Cirrhosis increases the risk of thromboembolic complications of atrial fibrillation.

Anticoagulants are necessary for the prevention of thrombosis and thromboembolic complications. However, there are no large prospective studies. There is insufficient data on the safety of anticoagulant therapy in cirrhosis. There are difficulties in monitoring anticoagulation in the application of vitamin K antagonists and low molecular weight heparins.

The review presents the available data on the use of warfarin, unfractionated heparin, low molecular weight heparins and direct oral anticoagulants in patients with liver cirrhosis, indicating the need for prevention of venous thrombosis in patients with risk factors, the possibility of preventing decompensation of cirrhosis, reducing the frequency of cardioembolic strokes in patients with atrial fibrillation.

Diagnosis, Development, and Treatment of Portal Vein Thrombosis in Patients With and Without Cirrhosis

Portal vein thrombosis unrelated to solid malignancy is common in patients with cirrhosis, but less frequently observed in patients without cirrhosis. Prompt diagnosis and management of acute symptomatic portal vein thrombosis are essential. Failure to detect and treat thromboses can result in mesenteric ischemia, chronic cavernous transformation, and complications of portal hypertension. In patients with cirrhosis, development of portal vein thrombosis is often insidious and remains undetected until its incidental detection. Management of portal vein thrombosis in patients with cirrhosis is more controversial. However, there are data to support treatment of specific patients with anticoagulation agents. We review the common and distinct features of portal vein thromboses in patients without liver tumors, with and without cirrhosis.

Liver stiffness and thrombin generation in compensated cirrhosis

BACKGROUND

Decompensated cirrhosis is associated with coagulation abnormalities that can increase the risk of thrombosis and bleeding. It is unclear precisely when these abnormalities arise and whether they are exacerbated as compensated cirrhosis progresses. Transient elastography using FibroScan generates liver stiffness measurements (LSM) that associate with portal hypertension, clinical outcomes and provides prognostic information at an earlier stage than traditional liver function scores eg, MELD score.

OBJECTIVE

To characterize thrombin generation in patients with compensated cirrhosis and to determine whether parameters of coagulation change throughout compensated cirrhosis, staged using LSM.

PATIENTS/METHODS

Blood samples were collected from well-compensated cirrhotic patients n = 61, All Child Pugh A stage) attending the Mater Misericordiae University Hospital, Ireland. Comprehensive clinical staging of liver disease, including LSM, was performed. Tissue Factor-stimulated thrombin generation was measured by calibrated automated thrombography.

RESULTS

Using LSM to stage well-compensated cirrhotic patients, we demonstrate a significant decrease in the rate of propagation, the rate of attenuation, and total thrombin generation as LSM increase. LSM correlated with endogenous thrombin potential, peak thrombin generation, the rate of propagation, and the rate of attenuation. This association between thrombin generation and LSM was still evident in sub-analyses excluding patients with ongoing alcohol use, active HCV infection, or a history of decompensation. In contrast, there was no significant correlation between thrombin generation, prothrombin times, Child-Pugh scores, or MELD scores.

CONCLUSION

Liver stiffness measurements identify differences in parameters of thrombin generation within a cohort of compensated cirrhotic patients before changes in clotting times occur.

Prediction of features of the course of chronic hepatitis C using Bayesian networks

MATERIALS AND METHODS

253 patients with chronic hepatitis C (CHC) and liver cirrhosis were included in the study. Assessment of gene polymorphisms of genes involved in inflammatory reactions and antiviral immunity (IL-1β-511C/T, IL-10 -1082G/A, IL28B C/T, IL28B T/G, TNF-α -238G/A, TGF-β -915G/C, IL-6 -174G/C), activators of local hepatic fibrosis (AGT G-6A, AGT 235 M/T, ATR1 1166 A/C), hemochromatosis (HFE C282Y, HFE H63D), platelet receptors (ITGA2 807 C/T, ITGB3 1565 T/C), coagulation proteins and endothelial dysfunction (FII 20210 G/A, FV 1691G/A, FVII 10976 G/A, FXIII 103 G/T, eNOS 894 G/T, CYBA 242 C/T, FBG -455 G/A, PAI-675 5G/4G, MTHFR 677 C/T) was carried. Using Bayesian networks we studied the predictor value of clinical and laboratory factors for the following conditions - end points (EP): development of cirrhosis (EP1), fibrosis rate (EP2), presence of portal hypertension (EP3) and cryoglobulins (EP4).

RESULTS AND DISCUSSION

In addition to traditional factors we have shown the contribution of the following mutations. Predicting EP1- liver cirrhosis - HFE H63D, C282Y, CYBA 242 C/T, AGT G-6G, ITGB31565 T/C gene mutations were significant. We also found a link between the rate of progression of liver fibrosis and gene polymorphisms of AGT G-6G, AGT M235T, FV 1691G/A, ITGB31565 T/C. Among the genetic factors associated with portal hypertension there are gene polymorphisms of PAI-I-675 5G/4G, FII 20210 G/A, CYBA 242 C/T, HFE H63D and Il-6 174GC. Cryoglobulins and cryoglobuliemic vasculitis (EP4) are associated with gene mutations MTHFR C677T, ATR A1166C and HFE H63D.

CONCLUSION

The results obtained allow to detect the major pathophysiological and genetic factors which determine the status of the patient and the outcome of the disease, to clarify their contribution, and to reveal the significance of point mutations of genes that control the main routes of HCV course and progression.

Inhibition of activated factor X; a new pathway in ameliorating carbon tetrachloride-induced liver fibrosis in rats

Activated factor X has a central role in the coagulation activation and also contributes to chronic inflammation and tissue fibrosis. In this study, rivaroxaban, a direct factor X inhibitor, attenuates liver fibrosis induced by carbon tetrachloride (CCl₄ ). Male rats were randomly allocated into three groups: a control group, CCl ₄ fibrotic group, and CCl ₄ +rivaroxaban (5 mg/kg) group. Liver fibrosis was induced by subcutaneous injection of CCl ₄ twice a week for 6 weeks. Rivaroxaban significantly restored the biochemical parameter including inflammatory and fibrosis markers with histopathological evidence using routine and Masson trichrome staining. It reduced also the expression of tissue factor, fibrin, transforming growth factor and α-smooth muscle actin in the liver tissues. This concludes that rivaroxaban attenuates liver injury caused by CCl ₄ , at least in part by inhibiting coagulation and proinflammatory activation. In conclusion, rivaroxaban may be used for the management of liver fibrosis.

Chronic liver injury drives non-traditional intrahepatic fibrin(ogen) crosslinking via tissue transglutaminase

Essentials Fibrin clots are often implicated in the progression of liver fibrosis. Liver fibrosis was induced in transgenic mice with defects in clot formation or stabilization. Liver fibrosis and fibrin(ogen) deposition do not require fibrin polymerization or factor XIIIa. Fibrin(ogen) is an in vivo substrate of tissue transglutaminase in experimental liver fibrosis. SUMMARY: Background Intravascular fibrin clots and extravascular fibrin deposits are often implicated in the progression of liver fibrosis. However, evidence supporting a pathological role of fibrin in hepatic fibrosis is indirect and based largely on studies using anticoagulant drugs that inhibit activation of the coagulation protease thrombin, which has other downstream targets that promote fibrosis. Therefore, the goal of this study was to determine the precise role of fibrin deposits in experimental hepatic fibrosis. Methods Liver fibrosis was induced in mice expressing mutant fibrinogen insensitive to thrombin-mediated proteolysis (i.e. locked in the monomeric form), termed FibAEK mice, and factor XIII A2 subunit-deficient (FXIII-/- ) mice. Female wild-type mice, FXIII-/- mice and homozygous FibAEK mice were challenged with carbon tetrachloride (CCl4 ) twice weekly for 4 weeks or 6 weeks (1 mL kg-1 , intraperitoneal). Results Hepatic injury and fibrosis induced by CCl4 challenge were unaffected by FXIII deficiency or inhibition of thrombin-catalyzed fibrin polymer formation (in FibAEK mice). Surprisingly, hepatic deposition of crosslinked fibrin(ogen) was not reduced in CCl4 -challenged FXIII-/- mice or FibAEK mice as compared with wild-type mice. Rather, deposition of crosslinked hepatic fibrin(ogen) following CCl4 challenge was dramatically reduced in tissue transglutaminase-2 (TGM2)-deficient (TGM2-/- ) mice. However, the reduction in crosslinked fibrin(ogen) in TGM2-/- mice did not affect CCl4 -induced liver fibrosis. Conclusions These results indicate that neither traditional fibrin clots, formed by the thrombin-activated FXIII pathway nor atypical TGM2-crosslinked fibrin(ogen) contribute to experimental CCl4 -induced liver fibrosis. Collectively, the results indicate that liver fibrosis occurs independently of intrahepatic fibrin(ogen) deposition.

Coagulation, Microenvironment and Liver Fibrosis

Fibrosis is the main consequence of any kind of chronic liver damage. Coagulation and thrombin generation are crucial in the physiological response to tissue injury; however, the inappropriate and uncontrolled activation of coagulation cascade may lead to fibrosis development due to the involvement of several cellular types and biochemical pathways in response to thrombin generation. In the liver, hepatic stellate cells and sinusoidal endothelial cells orchestrate fibrogenic response to chronic damage. Thrombin interacts with these cytotypes mainly through protease-activated receptors (PARs), which are expressed by endothelium, platelets and hepatic stellate cells. This review focuses on the impact of coagulation in liver fibrogenesis, describes receptors and pathways involved and explores the potential antifibrotic properties of drugs active in hemostasis in studies with cells, animal models of liver damage and humans.

Major Changes of von Willebrand Factor Multimer Distribution in Cirrhotic Patients with Stable Disease or Acute Decompensation

Background  There is an unstable balance between pro- and anti-haemostatic processes in patients with cirrhosis. We hypothesized, that in patients with acute decompensation (AD) the major alterations of von Willebrand factor (VWF) could contribute to the pro-thrombotic situation as compared to patients with stable (ST) cirrhosis.

Patients and Methods  We analysed different parameters of VWF, including detailed multimer distribution by densitometry and platelet adhesion, together with ad isintegrin-like a nd m etalloproteinase with t hrombo s pondin type-1 motifs 13 (ADAMTS13) activity and antigen and C-reactive protein (CRP) levels in patients with ST cirrhosis ( n  = 99), with AD ( n  = 54) and controls ( n  = 92).

Results  VWF antigen, ristocetin co-factor as well as collagen-binding activities were elevated in both cirrhotic groups in a stepwise manner. There was a decrease in high and an increase in low molecular weight multimer ratios in the majority of ST cirrhosis. However, in 24 out of 54 AD patients, ultra-large VWF multimers (ultra-large molecular weight multimers [ULMWM]) were found. ADAMTS13 activity in ST and AD patients without ULMWM was similar to controls (median [interquartile range; IQR]%: 98 [67–132] and 91 [60–110] vs. 106 [88–117], respectively). The presence of ULMWM in AD patients was associated with low ADAMTS13 activity [33 (24–49)%] and high CRP level [23 (7.1–83.6) mg/L]. Adhesion of normal platelets showed a stepwise increase in the presence of cirrhotic plasmas, reaching the highest level in AD patients with ULMWM.

Conclusion  Characteristic changes of VWF parameters are seen in ST cirrhosis. In AD patients, highly increased VWF and reduced ADAMTS13 activity could be found, along with the presence of ULMWM, which are possible markers and contributors of the disease progression.

The Role of Anticoagulation in Treating Portal Hypertension

PURPOSE OF REVIEW

To revise experimental and clinical data supporting a less traditional role of anticoagulation for treating portal hypertension in patients with cirrhosis.

RECENT FINDINGS

Portal hypertension is the main driver of complications such as ascites, variceal hemorrhage, and hepatic encephalopathy, with inflammation as a key component. The traditional view of cirrhosis as a pro-hemorrhagic condition has recently changed, prothrombotic complications being recognized as frequently as the hemorrhagic ones. Several data indicate a close relationship between inflammation, prothrombotic status, worsening of hepatic fibrosis, and portal hypertension both in animal models and in patients with chronic liver disease. These findings indicate that anticoagulation may represent a potent tool to act on fibrogenesis and therefore consequently to treat portal hypertension. All anticoagulants have good to optimal safety profiles and can be used in patients with advanced chronic liver disease with confidence.

SUMMARY

Anticoagulation has a role as a pleiotropic treatment of portal hypertension in cirrhosis.

Thrombin and factor Xa link the coagulation system with liver fibrosis

Background

Thrombin activates hepatic stellate cells via protease-activated receptor-1. The role of Factor Xa (FXa) in hepatic fibrosis has not been elucidated. We aimed to evaluate the impact of FXa and thrombin in vitro on stellate cells and their respective inhibition in vivo using a rodent model of hepatic fibrosis.

Methods

HSC-LX2 cells were incubated with FXa and/or thrombin in cell culture, stained for αSMA and relative gene expression and gel contraction calculated. C57BL/6 J mice were administered thioacetamide (TAA) for 8 weeks with Rivaroxaban (n = 15) or Dabigatran (n = 15). Control animals received TAA alone (n = 15). Fibrosis was scored and quantified using digital image analysis and hepatic tissue hydroxyproline estimated.

Results

Stellate cells treated with FXa and thrombin demonstrated upregulation of procollagen, TGF-beta, αSMA and significant cell contraction (43.48%+/− 4.12) compared to culturing with FXa or thrombin alone (26.90%+/− 8.90, p = 0.02; 13.1%+/− 9.84, p < 0.001). Mean fibrosis score, percentage area of fibrosis and hepatic hydroxyproline content (2.46 vs 4.08, p = 0.008; 2.02% vs 3.76%, p = 0.012; 276.0 vs 651.3, p = 0.0001) were significantly reduced in mice treated with the FXa inhibitor compared to control mice. FXa inhibition was significantly more effective than thrombin inhibition in reducing percentage area of fibrosis and hepatic hydroxyproline content (2.02% vs 3.70%,p = 0.031; 276.0 vs 413.1,p = 0.001).

Conclusions

FXa promotes stellate cell contractility and activation. Early inhibition of coagulation using a FXa inhibitor significantly reduces TAA induced murine liver fibrosis and may be a viable treatment for liver fibrosis in patients.

Portal vein thrombosis in cirrhosis: diagnosis, natural history, and therapeutic challenges

Portal vein thrombosis (PVT) is a frequent complication in cirrhosis and its prevalence increases with disease severity. Several factors are involved in the development and progression of PVT. The challenge for the management of PVT is the precise evaluation of the bleeding risk as opposed to life-threatening extension of thrombosis. Nevertheless, the impact on the progression and outcome of liver disease is unclear. A critical evaluation of the available data discloses that treating PVT in cirrhotics is safe and effective. However, there are open issues, such as which anticoagulant could represent a safer therapeutic option, and when and for how long this treatment should be administered to cirrhotic patients with PVT.

Platelets as Modulators of Liver Diseases

Platelets are key players in thrombosis and hemostasis. Alterations in platelet count and function are common in liver disease, and may contribute to bleeding or thrombotic complications in liver diseases and during liver surgery. In addition to their hemostatic function, platelets may modulate liver diseases by mechanisms that are incompletely understood. Here, we present clinical evidence for a role of platelets in the progression of chronic and acute liver diseases, including cirrhosis, acute liver failure, and hepatocellular carcinoma. We also present clinical evidence that platelets promote liver regeneration following partial liver resection. Subsequently, we summarize studies in experimental animal models that support these clinical observations, and also highlight studies that are in contrast with clinical observations. The combined results of clinical and experimental studies suggest that platelets may be a therapeutic target in the treatment of liver injury and repair, but the gaps in our understanding of mechanisms involved in platelet-mediated modulation of liver diseases call for caution in clinical application of these findings.

Bleeding Risk with Invasive Procedures in Patients with Cirrhosis and Coagulopathy

PURPOSE OF REVIEW

Previous perceptions of cirrhosis as a hypocoagulable state have resulted in empirical blood product transfusions prior to invasive procedures. We evaluate procedure-related bleeding risks in patients with cirrhosis, assess the utility of conventional and newer global coagulation tests, and explore evidence surrounding prophylactic transfusion strategies.

RECENT FINDINGS

Recent literature supports the concept of a rebalanced, albeit fragile, haemostasis equilibrium in cirrhosis, with a potential hypercoagulable tendency in stable patients. Standard coagulation tests provide a poor reflection of bleeding risks and yet are relied upon for transfusion thresholds. Consequently, a sizeable proportion of patients receive unnecessary blood products. The role of viscoelastic tests to guide transfusions requires further evaluation. In stable cirrhotic patients, procedure-related bleeding rates appear low. Prophylactic transfusion strategies based on arbitrary thresholds lack evidence of clinical benefit. There is a pressing need for point-of-care coagulation tests that represent the complex coagulopathy of cirrhosis and well-powered randomised controlled trials to develop evidence-based pre-procedure transfusion guidelines.

Anticoagulation in chronic liver disease

In this Grand Round presentation, the case of a man with decompensated liver disease is described. He subsequently developed a fatal pulmonary embolism, which may not have occurred if he had been prescribed prophylactic anticoagulation to prevent venous thromboembolic disease. The burden of thrombotic disease in those with chronic liver disease is discussed, before a more detailed analysis of the current evidence, safety data, and clinical dilemmas regarding the use of anticoagulation in patients with chronic liver disease. Finally, the future directions within this field are explored.

Von Willebrand factor deficiency reduces liver fibrosis in mice

Liver diseases are associated with complex changes in the hemostatic system and elevated levels of the platelet-adhesive protein Von Willebrand factor (VWF) are reported in patients with acute and chronic liver damage. Although elevated levels of VWF are associated with fibrosis in the general population, the role of VWF in acute and chronic liver injury has not been examined in depth in experimental settings. We tested the hypothesis that VWF deficiency inhibits experimental liver injury and fibrosis. Wild-type (WT) and VWF-deficient mice were challenged with carbon tetrachloride (CCl₄) and the impact of VWF deficiency on acute liver injury and chronic liver fibrosis was determined. VWF deficiency did not significantly affect acute CCl₄-induced hepatocellular necrosis in mice. Chronic CCl₄ challenge, twice weekly for 6weeks, significantly increased hepatic stellate cell activation and collagen deposition in livers of WT mice. Interestingly, hepatic induction of several profibrogenic and stellate cell activation genes was attenuated in VWF-deficient mice. Moreover, birefringent sirius red staining (indicating type I and III collagens) and type I collagen immunofluorescence indicated a reduction in hepatic collagen deposition in CCl₄-exposed VWF-deficient mice compared to CCl₄-exposed WT mice. The results indicate that VWF deficiency attenuates chronic CCl₄-induced liver fibrosis without affecting acute hepatocellular necrosis. The results are the first to demonstrate that VWF deficiency reduces the progression of liver fibrosis, suggesting a mechanistic role of elevated plasma VWF levels in cirrhosis.

Portal vein thrombosis in patients with cirrhosis

Portal vein thrombosis (PVT) is frequent in patients with liver cirrhosis and possible severe complications such as mesenteric ischemia are rare, but can be life-threatening. However, different aspects of clinical relevance, diagnosis and management of PVT are still areas of uncertainty and investigation in international guidelines. In this article, we elaborate on PVT classification, geographical differences in clinical presentation and standards of diagnosis, and briefly on the current pathophysiological understanding and risk factors. This review considers and highlights the pitfalls of the various treatment approaches and prophylactic treatments. Finally, we review the controversial issue of clinical impact of PVT on prognosis, especially considering liver transplantation and future perspectives.

Impact of coagulation function and anticoagulation therapy on liver fibrosis

Liver cirrhosis and its complications, including esophageal and gastric variceal bleeding, hepatic encephalopathy, and ascites, can cause serious harm to human health. Therefore, treatment of liver fibrosis is key to the prevention and treatment of liver cirrhosis. In order to treat liver fibrosis to reduce human suffering, medical experts and scholars have performed many clinical and animal studies to find safe, efficient and reliable drugs to slow the progression of hepatic fibrosis and even reverse the liver function. This review introduces the definition of liver fibrosis in China and other countries, discusses the effect of coagulation on the process of liver fibrosis and various anticoagulation therapies for liver fibrosis, and summarizes the advantages, disadvantages, and side effects of different anticoagulants in the prevention and treatment of liver fibrosis.

Presence of atrial fibrillation is associated with liver stiffness in an elderly Finnish population

Background

Chronic liver injury from different etiologies drives liver fibrosis. However, little is known about the associated factors, systemic factors in particular. Recently, non-alcoholic fatty liver disease (NAFLD) and atrial fibrillation have been shown to be associated with each other. Thereby, we aimed to study the association between atrial fibrillation and liver stiffness.

Study

Extensive clinical measurements including echocardiography of the heart, transient elastography (TE) of the liver and the presence of atrial fibrillation were determined in elderly Finnish study subjects (n = 76, mean age 73 years) from OPERA (Oulu Project Elucidating the Risk of Atherosclerosis) study cohort. Half of the study subjects had non-alcoholic fatty liver disease, whereas others did not have any known hepatic morbidity. The present study was cross-sectional by nature.

Results

The subjects with atrial fibrillation had higher TE values (with atrial fibrillation TE = 9.3kPa, without atrial fibrillation TE = 6.3kPa, p = 0.018). When the cohort was divided to four subgroups (those without NAFLD or atrial fibrillation, with NAFLD but without atrial fibrillation, with both conditions, and with atrial fibrillation but without NAFLD), the TE value was the highest in the subjects with both conditions (5.3kPa, 7.4kPa, 10.8kPa and 7.8kPa, respectively, p = 0.019). Moreover, the higher the TE value, the more prevalent atrial fibrillation was (the atrial fibrillation prevalence by tertiles of TE 27% / 36% / 77%, p = 0.001). Likewise, the greater the TE value, the greater the left atrial diameter, a collateral of atrial fibrillation (left atrial diameters by tertiles of TE 39mm / 45mm / 48mm, p<0.001) was. All these p-values for continuous variables remained statistically significant even after adjustment for common clinically relevant risk factors.

Conclusions

There is an association between atrial fibrillation and liver stiffness. This novel association may have multiple explanations and mechanistic links, which are discussed here and need further studies, prospective studies in particular.

Anticoagulant therapy with fondaparinux in a liver transplant patient with thrombosis and liver fibrosis: a case report

The treatment with fondaparinux is the effective and safe anticoagulant therapy in liver transplant patient on immunosuppressive therapy with arterial thrombosis, and it seems able to reduce liver fibrosis. Although this treatment is not generalizable, further prospective large studies need to confirm this case report.

Lipoprotein(a) in patients with hepatocellular carcinoma and portal vein thrombosis

BACKGROUND

The mechanism for hypercoagulability in malignancy is not entirely understood. Although several studies report contrasting finding about the link between elevated plasma levels of the lipoprotein(a) [Lp(a)] and the possible recurrence of venous thromboembolism, we perform a study to evaluate the impact of the Lp(a) in the development of portal vein thromboembolism (PVT) in patients with HCC.

METHODS

We compared 44 PVT patients with 50 healthy subjects and 50 HCC patients.

RESULTS

The comparison between PVT patients and HCC showed in the former the mean value of serum lipoprotein levels was higher than 37.3 mg/dl (p = 0.000). The comparison between PVT versus healthy controls showed that in the former, mean value of serum lipoprotein levels was higher than 75 mg/dl (p = 0.000). The predictive value test of serum lipoprotein(a) on PVT was 0.72 and on HCC was 0.83. The odds ratio of lipoprotein(a) was 9.21 on PVT and 6.33 on HCC.

CONCLUSION

Patients with PVT and HCC showed a statistical significant serum lipoprotein(a) level higher than the subjects with HCC and no PVT or the healthy subject. So we assume a role of lipoprotein(a) as predictor of venous thromboembolism in neoplastic patients.

von Willebrand factor and procoagulant imbalance predict outcome in patients with cirrhosis and thrombocytopenia

BACKGROUND & AIMS

Several lines of evidence suggest that the hemostatic disorders of cirrhosis may have a significant clinical impact. We investigated the independent predictive value of components of the hemostatic system on the occurrence of ascites, variceal bleeding (VB), and survival.

METHODS

One hundred and two patients with thrombocytopenia (Child-Pugh class A/B/C: 34/34/34) were enrolled. Platelet counts, factors (F) II, V, VII, and VIII, antithrombin, protein C (PC), FVIII-to-PC ratio as an index of procoagulant imbalance, von Willebrand factor antigen (vWF-Ag), and model for end-stage liver disease (MELD) were evaluated. Two multivariate analyses were performed: one excluding (model 1) and one including MELD (model 2).

RESULTS

Higher vWF-Ag levels and FVIII-to-PC ratios were the most prominent hemostatic disorders in patients with cirrhosis. Increased levels of vWF-Ag and FVIII, and higher FVIII-to-PC ratios independently predicted the presence of ascites and varices at baseline. Independent predictors of ascites and VB during follow-up were vWF-Ag (model 1/2: p=0.001/p=0.009 and p=0.008/p=0.01, respectively) and FVIII-to-PC ratio (model 1/2: p=0.003/p=0.02 and p=0.01/p=0.03, respectively). vWF-Ag (model 1/2: p=0.007/p=0.002), FVIII-to-PC ratio (model 1/2: p=0.001/p=0.01), and MELD (p=0.02) independently predicted mortality. Patient groups with significantly higher probability of new-onset ascites, VB, and mortality were identified by certain cut-offs of vWF-Ag (213%, 466%, and 321%, respectively) and FVIII-to-PC ratio (1.99, 3.29, and 2.36, respectively). vWF-Ag and FVIII-to-PC ratio equaled MELD in mortality prediction.

CONCLUSIONS

Advanced cirrhosis is characterized by increased thrombotic potential. vWF-Ag and FVIII-to-PC ratio independently predict new-onset ascites, VB, and mortality. Targeting hypercoagulability could improve the outcome of patients with cirrhosis.

LAY SUMMARY

Higher von Willebrand factor antigen (vWF-Ag) levels and factor VIII-to-protein C (FVIII-to-PC) ratio are the prominent hemostatic disorders in patients with cirrhosis. vWF-Ag and FVIII-to-PC ratio independently predict new-onset ascites, variceal bleeding, and mortality in these patients.

A conceptual and practical approach to haemostasis in paediatric liver disease

Children with liver disease can develop severe bleeding episodes and thrombosis. Liver failure usually results in decreased levels of procoagulant and anticoagulant factors. Additional risk factors, including changes in vascular flow and endothelial function, are of importance for the development of bleeding or thrombosis in individual vascular beds. Detailed studies of haemostatic disturbances in the setting of paediatric liver disease are sparse and extrapolation from adult studies is common. The spectrum of liver diseases and the haemostatic system differs between children and adults. Specific paediatric liver diseases are reported to have more distinctive effects on haemostasis and the risk of bleeding and/or thrombosis.

CONCLUSION

we propose a model regarding haemostasis in paediatric liver disease, taking into account a number of specific variables and mechanisms, as well as the type of liver disease, which will provide a framework for clinical decision-making in these complex patients.

Role of hemostatic factors in hepatic injury and disease: animal models de-liver

Chronic liver damage is associated with unique changes in the hemostatic system. Patients with liver disease often show a precariously rebalanced hemostatic system, which is easily tipped towards bleeding or thrombotic complications by otherwise benign stimuli. In addition, some clinical studies have shown that hemostatic system components contribute to the progression of liver disease. There is a strong basic science foundation for clinical studies with this particular focus. Chronic and acute liver disease can be modeled in rodents and large animals with a variety of approaches, which span chronic exposure to toxic xenobiotics, diet-induced obesity, and surgical intervention. These experimental approaches have now provided strong evidence that, in addition to perturbations in hemostasis caused by liver disease, elements of the hemostatic system have powerful effects on the progression of experimental liver toxicity and disease. In this review, we cover the basis of the animal models that are most often utilized to assess the impact of the hemostatic system on liver disease, and highlight the role that coagulation proteases and their targets play in experimental liver toxicity and disease, emphasizing key similarities and differences between models. The need to characterize hemostatic changes in existing animal models and to develop novel animal models recapitulating the coagulopathy of chronic liver disease is highlighted. Finally, we emphasize the continued need to translate knowledge derived from highly applicable animal models to improve our understanding of the reciprocal interaction between liver disease and the hemostatic system in patients.

Role of Fibrin(ogen) in Progression of Liver Disease: Guilt by Association?

Strong experimental evidence indicates that components of the hemostatic system, including thrombin, exacerbate diverse features of experimental liver disease. Clinical studies have also begun to address this connection and some studies have suggested that anticoagulants can improve outcome in patients with liver disease. Among the evidence of coagulation cascade activation in models of liver injury and disease is the frequent observation of thrombin-driven hepatic fibrin(ogen) deposition. Indeed, hepatic fibrin(ogen) deposition has long been recognized as a consequence of hepatic injury. Although commonly inferred as pathologic due to protective effects of anticoagulants in mouse models, the role of fibrin(ogen) in acute liver injury and chronic liver disease may not be universally detrimental. The localization of hepatic fibrin(ogen) deposits within the liver is connected to the disease stimulus and in animal models of liver toxicity and chronic disease, fibrin(ogen) deposition may not always be synonymous with large vessel thrombosis. Here, we provide a balanced review of the experimental evidence supporting a direct connection between fibrin(ogen) and liver injury/disease pathogenesis, and suggest a path forward bridging experimental and clinical research to improve our knowledge on the nature and function of fibrin(ogen) in liver disease.