Thrombotic risk factors and liver histologic lesions in non-alcoholic fatty liver disease

No evidence of association between inherited thrombophilia and increased risk of liver fibrosis

BACKGROUND

Preliminary evidence suggests that inherited hypercoagulable disorders can lead to an increased risk of significant liver fibrosis.

OBJECTIVE

We aimed to investigate the prevalence of significant fibrosis in patients with inherited thrombophilia, assessed by using liver stiffness (LS), and to compare this prevalence to that found in a large population-based cohort from the same region.

METHODS

This was a single-center, cross-sectional study. A complete laboratory analysis for liver disease, LS by transient elastography and an abdominal ultrasound were performed in patients with inherited thrombophilia diagnosed between May 2013-February 2017. These patients were propensity score matched (ratio 1:4) with a population-based cohort from the same region (PREVHEP-ETHON study; NCT02749864; N = 5988).

RESULTS

Of 241 patients with inherited thrombophilia, eight patients (3.3%) had significant fibrosis (LS ≥8 kPa). All of them had risk factors for liver disease and met diagnostic criteria for different liver diseases. After matching 221 patients with thrombophilia with 884 patients of the PREVHEP-ETHON cohort, the prevalence of significant fibrosis was similar between both cohorts (1.8% vs. 3.6%, p = 0.488). Multivariate analysis showed that age and liver disease risk factors, but not belonging to the thrombophilia cohort, were associated with the presence of significant fibrosis. The magnitude of the increased risk of significant fibrosis in patients with risk factors for liver disease was also similar in both cohorts.

CONCLUSIONS

Our findings do not provide evidence supporting an association between inherited thrombophilia and an increased risk of significant liver fibrosis, independent of the presence of liver-related causes of fibrosis.

Portal Vein Thrombosis in Patients with Liver Cirrhosis: What Went Wrong?

Purpose

This study aimed to explore inflammatory biomarkers, stool's functional bacterial groups and their possible link to portal vein thrombosis (PVT) in patients with liver cirrhosis (LC).

Materials and Methods

An observational study of 300 participants: 200 inhospital cirrhotic patients, who met inclusion criteria, equally assigned into two groups, based on the presence or absence of PVT and 100 healthy controls was carried out.

Results

The PVT group displayed significant differences related to older age, cigarettes smoking history, emergency admission, higher Child-Pugh score, metabolic related disorders and nonalcoholic fatty liver disease, as well as non-obstructive aspects, with chronic thrombi. The PVT group exhibited significant differences related to biomarkers such as tumor necrosis factor (TNF)-alpha, C-reactive protein (CRP), D-dimers (D-D), as well as gut overall dysbiosis (DB) and alteration of different functional bacterial groups of the gut microbiota. Strong positive correlations were observed between PVT severity, and TNF-alpha, CRP, D-D as well as lipopolysaccharide (LPS) positive bacteria. Esophageal varices, age and abdominal pain were independent predictors for PVT severity as well as CRP, TNF-alpha and D-D.

Conclusion

Patients with LC and PVT displayed elevation of TNF-alpha, CRP, D-D alterations of the functional gut microbiota, as well as several morphological and clinical particularities. Although the LPS positive gut microbiota was linked to inflammatory biomarkers and PVT severity, it was not proven to be an independent predictor of the PVT severity like CRP, TNF-alpha and D-D.

Insight into increased risk of portal vein thrombosis in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the leading chronic liver diseases with increased morbidity and mortality rates for extrahepatic diseases (including cardiovascular disease, portal vein thrombosis, etc.). There is an increased risk of thrombosis in both the portal and systemic circulation in patients with NAFLD, independent of traditional liver cirrhosis. However, increased portal pressure, the most critical factor, is frequently observed in NAFLD patients, predisposing them to portal vein thrombosis (PVT). It has been reported that there is an 8.5% incidence of PVT among patients with non-cirrhotic NAFLD in a prospective cohort study. Based on the prothrombotic status of NAFLD itself, patients combined with cirrhosis may accelerate the development of PVT and lead to a poor prognosis. Moreover, PVT has been shown to complicate the procedure and adversely affect the outcome during liver transplantation surgery. NAFLD is in a prothrombotic state, and its underlying mechanisms have not been fully understood so far. Particularly noteworthy is that gastroenterologists currently overlook the higher risk of PVT in NAFLD. We investigate the pathogenesis of NAFLD complicated with PVT from the perspective of primary, secondary, and tertiary hemostasis, and also summarize relevant studies in humans. Some treatment options that may affect NAFLD and its PVT are also explored to improve patient-oriented outcomes.

Coagulation and Endothelial Dysfunction Associated with NAFLD: Current Status and Therapeutic Implications

Non-alcoholic fatty liver disease (NAFLD) is closely related to insulin resistance, type 2 diabetes mellitus and obesity. It is considered a multisystem disease and there is a strong association with cardiovascular disease and arterial hypertension, which interfere with changes in the coagulation system. Coagulation disorders are common in patients with hepatic impairment and are dependent on the degree of liver damage. Through a review of the literature, we consider and discuss possible disorders in the coagulation cascade and fibrinolysis, endothelial dysfunction and platelet abnormalities in patients with NAFLD.

Therapeutic potential of policosanol in the concurrent management of dyslipidemia and non-alcoholic fatty liver disease

Background

High-fat diet (HFD) possesses a major cause of cardiovascular disease, and hepatosteatosis. Unfortunately, long-term use of statins has a theoretical possibility of worsening of hepatic histology in the patients with non-alcoholic fatty liver disease (NAFLD). The objective of the study was to explore hepatoprotective potential of policosanol as an alternative to statins in experimental NAFLD. For the same, young male Wistar rats were fed with HFD for 8 weeks to induce NAFLD. 48 adult Wistar rats were distributed into six investigational groups: normal control, HFD control, and four treatment groups, receiving policosanol (50 and 100 mg/kg/day), atorvastatin (30 mg/kg/day), and silymarin (100 mg/kg/day) for 8 weeks along with HFD.

Result

HFD consumption caused profound hepatotoxicity evident by hepatic oxidative stress, increased Serum glutamic oxaloacetic transaminase (SGOT), Serum glutamic pyruvic transaminase (SGPT), Alkaline phosphatase (ALP), and bilirubin content. Treatment with policosanol (100 mg/kg) markedly reduced the elevated SGOT, SGPT, and ALP levels in HFD-fed rats. Moreover, policosanol significantly reduced hepatic oxidative stress manifest by reduced malondialdehyde (MDA) and increased glutathione (GSH) level. The treatment with policosanol (100 mg/kg) was found to be more active in attenuating the HFD-induced hepatotoxicity as compared to policosanol (50 mg/kg) and atorvastatin (30 mg/kg). Moreover, we observed that the hepatoprotective potential of policosanol was comparable to the silymarin.

Conclusions

The results of the study clearly indicated that the policosanol could be considered an intriguing approach for the treatment of NAFLD.

Plasminogen activator inhibitor is significantly elevated in liver transplant recipients with decompensated NASH cirrhosis

Background

Non-alcoholic fatty liver disease is a prohaemostatic state with abnormal primary, secondary and tertiary haemostasis. Plasminogen activator inhibitor (PAI)-1 is the best-established marker for prohaemostasis in non-alcoholic fatty liver disease. While epidemiological studies demonstrate decompensated non-alcoholic steatohepatitis (NASH) cirrhosis patients have increased rates of venous thromboembolism, including portal vein thrombosis, mechanistic studies have focused exclusively on patients without or with compensated cirrhosis. We aimed to characterizecharacterise PAI-1 levels in decompensated NASH cirrhosis.

Methods

PAI-1 level was measured in consecutive adult liver transplant recipients immediately prior to liver transplantation. Multivariable models were constructed using linear regression to assess factors related to PAI-1 level.

Results

Forty-six subjects with mean age 57 (IQR 53–62) years and Model for Endstage Liver Disease (MELD) score of 34 (IQR 30–40) were enrolled. Baseline characteristics were similar between NASH (n=10) and non-NASH (n=36) subjects except for rates of diabetes and hyperlipidaemia. Mean PAI-1 level was greater in NASH (53.9, 95% CI 33.3 to 74.5 mg/mL) when compared with non-NASH (36.1, 95% CI 28.7 to 43.5), p=0.040. NASH remained independently predictive of PAI-1 level prior to transplant on adjusted multivariable modelling (β 40.13, 95% CI 14.41 to 65.86, p=0.003). Conclusions: PAI-1 level is significantly elevated in decompensated NASH cirrhosis independent of other pro-haemostatic factors. This may explain the greater rates of venous thromboembolism in decompensated NASH cirrhosis. Future study focusing on prevention of venous thromboembolism in this population is paramount to improve patient-oriented outcomes given the high morbidity and mortality of venous thromboembolism and the significant impact it has on transplant candidacy.

Hemostatic alterations linked to body fat distribution, fatty liver, and insulin resistance

OBJECTIVE

Obesity, in particular visceral obesity, and insulin resistance emerged as major risk factors for severe coronavirus disease 2019 (COVID-19), which is strongly associated with hemostatic alterations. Because obesity and insulin resistance predispose to thrombotic diseases, we investigated the relationship between hemostatic alterations and body fat distribution in participants at risk for type 2 diabetes.

SUBJECTS

Body fat distribution (visceral and subcutaneous abdominal adipose tissue) and liver fat content of 150 participants - with impaired glucose tolerance and/or impaired fasting glucose - were determined using magnetic resonance imaging and spectroscopy. Participants underwent precise metabolic characterization and major hemostasis parameters were analyzed.

RESULTS

Procoagulant factors (FII, FVII, FVIII, and FIX) and anticoagulant proteins (antithrombin, protein C, and protein S) were significantly associated with body fat distribution. In patients with fatty liver, fibrinogen (298 mg/dl vs. 264 mg/dl, p = 0.0182), FVII (99% vs. 90%, p = 0.0049), FVIII (114% vs. 90%, p = 0.0098), protein C (124% vs. 111%, p = 0.0006), and protein S (109% vs. 89%, p < 0.0001) were higher than in controls. In contrast, antithrombin (97% vs. 102%, p = 0.0025) was higher in control patients. In multivariate analyses controlling for insulin sensitivity, body fat compartments, and genotype variants (PNPLA3^I148MM/MI/TM6SF2^E167kK/kE), only protein C and protein S remained significantly increased in fatty liver.

CONCLUSIONS

Body fat distribution is significantly associated with alterations of procoagulant and anticoagulant parameters. Liver fat plays a key role in the regulation of protein C and protein S, suggesting a potential counteracting mechanism to the prothrombotic state in subjects with prediabetes and fatty liver.

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.

Nonalcoholic steatohepatitis Fitness Intervention in Thrombosis (NASHFit): Study protocol for a randomized controlled trial of a supervised aerobic exercise program to reduce elevated clotting risk in patients with NASH

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide affecting upwards of one third the global population. For reasons not fully understood, individuals with NAFLD and its more severe variant, nonalcoholic steatohepatitis (NASH), are at increased risk for venous thromboembolism which significantly increases morbidity and mortality. Lifestyle changes centering around exercise training are the mainstay of treatment for NAFLD/NASH. While exercise training can lessen venous thromboembolic risk in healthy persons and those with cardiovascular disease, whether or not this benefit is seen in patients with NAFLD/NASH remains unknown. In order to better understand how exercise training impacts thrombosis risk in NAFLD, we present the design of a thirty-two week randomized controlled clinical trial of 42 sedentary subjects age 18-69 with biopsy proven NASH. The main aim is to determine the impact of an aerobic exercise training program on the abnormal hemostatic system unique to NAFLD/NASH. The main outcome is change in plasminogen activator inhibitor one level, an established marker for venous thromboembolism. Secondary outcomes include body composition, cardiorespiratory fitness, control of comorbid metabolic conditions (e.g., obesity, hypertension, hyperlipidemia, diabetes), dietary composition, health related quality of life, liver enzymes and histology, NAFLD/NASH disease activity (e.g., biomarkers, clinical decision aids), microbiome, other markers of hemostasis, and PNPLA3 gene expression. The study represents the first clinical trial of an exercise training program to reduce elevated clotting risk in subjects with NAFLD/NASH.

Nonalcoholic Fatty Liver Disease Pandemic Fuels the Upsurge in Cardiovascular Diseases

Cardiovascular diseases (CVDs) remain a leading cause of death worldwide. Among the major risk factors for CVD, obesity and diabetes mellitus have received considerable attention in terms of public policy and awareness. However, the emerging prevalence of nonalcoholic fatty liver disease (NAFLD), as the most common liver and metabolic disease and a cause of CVD, has been largely overlooked. Currently, the number of individuals with NAFLD is greater than the total number of individuals with diabetes mellitus and obesity. Epidemiological studies have established a strong correlation between NAFLD and an increased risk of CVD and CVD-associated events. Although debate continues over the causal relationship between NAFLD and CVD, many mechanistic and longitudinal studies have indicated that NAFLD is one of the major driving forces for CVD and should be recognized as an independent risk factor for CVD apart from other metabolic disorders. In this review, we summarize the clinical evidence that supports NAFLD as a risk factor for CVD epidemics and discuss major mechanistic insights regarding the acceleration of CVD in the setting of NAFLD. Finally, we address the potential treatments for NAFLD and their potential impact on CVD.

Effectiveness of venous thromboembolism prophylaxis in patients with liver disease

BACKGROUND

Patients with liver disease are concomitantly at increased risk of venous thromboembolism (VTE) and bleeding events due to changes in the balance of pro- and anti-hemostatic substances. As such, recommendations for the use of pharmacological VTE prophylaxis are lacking. Recent studies have found no difference in rates of VTE in those receiving and not receiving pharmacological VTE prophylaxis, though most studies have been small. Thus, our study sought to establish if pharmacological VTE prophylaxis is effective and safe in patients with liver disease.

AIM

To determine if there is net clinical benefit to providing pharmacological VTE prophylaxis to cirrhotic patients.

METHODS

In this retrospective study, 1806 patients were propensity matched to assess if pharmacological VTE prophylaxis is effective and safe in patients with cirrhosis. Patients were divided and evaluated based on receipt of pharmacological VTE prophylaxis.

RESULTS

The composite primary outcome of VTE or major bleeding was more common in the no prophylaxis group than the prophylaxis group (8.7% vs 5.1%, P = 0.002), though this outcome was driven by higher rates of major bleeding (6.9% vs 2.9%, P < 0.001) rather than VTE (1.9% vs 2.2%, P = 0.62). There was no difference in length of stay or in-hospital mortality between groups. Pharmacological VTE prophylaxis was independently associated with lower rates of major bleeding (OR = 0.42, 95%CI: 0.25-0.68, P = 0.0005), but was not protective against VTE on multivariable analysis.

CONCLUSION

Pharmacological VTE prophylaxis was not associated with a significant reduction in the rate of VTE in patients with liver disease, though no increase in major bleeding events was observed.

Clinical significance of hepatic steatosis according to coronary plaque morphology: assessment using controlled attenuation parameter

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) plays a significant role in coronary atherosclerosis, independent of shared metabolic risk factors. The measurement of the controlled attenuation parameter (CAP) has shown to allow early and noninvasive detection of NAFLD at subclinical stage. We evaluated the significance of CAP-defined NAFLD in association with the presence of any type of coronary plaques and different plaque compositions.

METHODS

We conducted a retrospective cohort of apparently healthy subjects who had liver Fibroscan and coronary computed tomography during health screening exams.

RESULTS

A greater number of subjects with CAP-defined NAFLD was found in group with coronary plaques (61.3% vs. 73.5%, p = 0.005 without vs. with any type of plaque). From multivariate regression model, CAP ≥ 222 dB/m was an independent and significant parameter associated with the presence of coronary plaques, after adjusting possible confounders (OR 1.624, 95% 1.047-2.518, p = 0.030). Interestingly, CAP ≥ 222 dB/m was significantly associated with non-calcified plaque (adjusted OR 3.528, 95% CI 1.463-8.511, p = 0.005), whereas it was not significant in calcified plaques (p = 0.171).

CONCLUSION

CAP-defined NAFLD is independently associated with coronary plaques, especially non-calcified plaques. The association between NAFLD and non-calcified plaques suggests that particular attention should be given to the subjects with NAFLD for primary prevention.

Increased risk of venous thromboembolism in hospitalized patients with cirrhosis due to non-alcoholic steatohepatitis

Objective

Patients with cirrhosis are at increased risk for venous thromboembolism (VTE) and portal vein thrombosis (PVT). Cirrhosis due to non-alcoholic steatohepatitis (NASH) appears to be particularly prothrombotic. We investigated hospitalized patients with NASH cirrhosis to determine if they are at increased risk for VTE.

Methods

Data on adult hospitalized patients with cirrhosis and VTE (deep vein thrombosis and/or pulmonary embolism) between November 1, 2010 and December 31, 2015 were obtained. Cases with VTE were matched by age, gender, and model for end stage liver disease (MELD) score to corresponding controls without VTE.

Results

Two hundred and ninety subjects (145 matched pairs) with mean age of 58.4 ± 11.8 years and MELD score of 16.0 ± 7.2 were included. Baseline characteristics were similar between cases and controls. Independent adjusted risk factors for VTE included NASH (OR: 2.46, 95% CI: 1.07–5.65, p = 0.034), prior VTE (OR: 7.12, 95% CI: 1.99–25.5, p = 0.003), and presence of PVT (OR: 2.18, 95% CI: 1.03–4.58, p = 0.041). Thrombocytopenia was associated with decreased risk (OR: 0.49, 95% CI: 0.26–0.95, p = 0.035).

Conclusions

NASH is an independent risk factor for VTE among cirrhosis patients and provides further evidence that NASH is a hypercoagulable state. While all hospitalized patients with cirrhosis at risk for VTE should be considered for medical thromboprophylaxis, those with NASH cirrhosis are at particularly increased risk and therefore a high index of suspicion for VTE should be maintained even in the presence of thromboprophylaxis.

Thrombin promotes diet-induced obesity through fibrin-driven inflammation

Obesity promotes a chronic inflammatory and hypercoagulable state that drives cardiovascular disease, type 2 diabetes, fatty liver disease, and several cancers. Elevated thrombin activity underlies obesity-linked thromboembolic events, but the mechanistic links between the thrombin/fibrin(ogen) axis and obesity-associated pathologies are incompletely understood. In this work, immunohistochemical studies identified extravascular fibrin deposits within white adipose tissue and liver as distinct features of mice fed a high-fat diet (HFD) as well as obese patients. Fibγ390-396A mice carrying a mutant form of fibrinogen incapable of binding leukocyte αMβ2-integrin were protected from HFD-induced weight gain and elevated adiposity. Fibγ390-396A mice had markedly diminished systemic, adipose, and hepatic inflammation with reduced macrophage counts within white adipose tissue, as well as near-complete protection from development of fatty liver disease and glucose dysmetabolism. Homozygous thrombomodulin-mutant ThbdPro mice, which have elevated thrombin procoagulant function, gained more weight and developed exacerbated fatty liver disease when fed a HFD compared with WT mice. In contrast, treatment with dabigatran, a direct thrombin inhibitor, limited HFD-induced obesity development and suppressed progression of sequelae in mice with established obesity. Collectively, these data provide proof of concept that targeting thrombin or fibrin(ogen) may limit pathologies in obese patients.

Coagulopathy Before and After Liver Transplantation: From the Hepatic to the Systemic Circulatory Systems

The hemostatic environment in patients with cirrhosis is a delicate balance between prohemostatic and antihemostatic factors. There is a lack of effective laboratory measures of the hemostatic system in patients with cirrhosis. Many are predisposed to pulmonary embolus, deep vein thrombosis, and portal vein thrombosis in the pretransplantation setting. This pretransplantation hypercoagulable milieu seems to extend for at least several months post-transplantation. Patients with nonalcoholic fatty liver disease, inherited thrombophilia, portal hypertension in the absence of cirrhosis, and hepatocellular carcinoma often require individualized approach to anticoagulation. Early reports suggest a potential role for low-molecular-weight heparins and direct-acting anticoagulants.

Preserved hemostatic status in patients with non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is associated with an increased risk of thrombosis. However, it remains unclear if hypercoagulability contributes to this risk. We, therefore, determined an in-depth hemostatic profile in a cohort of well-defined patients with NAFLD.

METHODS

We drew blood samples from 68 patients with biopsy-proven NAFLD (simple steatosis n=24, NASH n=22, and NASH cirrhosis n=22), 30 lean controls, 30 overweight controls (body mass index (BMI) >25kg/m²), and 15 patients with alcoholic (ASH) cirrhosis, and performed in-depth hemostatic profiling.

RESULTS

Basal and agonist-induced platelet activation, plasma levels of markers of platelet activation, and plasma levels of the platelet adhesion regulators von Willebrand factor and ADAMTS13 were comparable between patients with non-cirrhotic NAFLD and controls. Agonist-induced platelet activation was decreased in patients with cirrhosis. Thrombomodulin-modified thrombin generation was comparable between all patients and controls, although patients with cirrhosis had a reduced anticoagulant response to thrombomodulin. Thromboelastography test results were comparable between controls and non-cirrhotic NAFLD patients, but revealed moderate hypocoagulability in cirrhosis. Plasma fibrinolytic potential was decreased in overweight controls and non-cirrhotic NAFLD, but accelerated fibrinolysis was observed in ASH cirrhosis. Clot permeability was decreased in overweight controls and patients with NAFLD.

CONCLUSIONS

The overall hemostatic profile is comparable between patients with non-cirrhotic NAFLD and controls. Additionally, pro-thrombotic features (hypofibrinolysis and a pro-thrombotic structure of fibrin clot) in patients with NAFLD are likely driven by obesity. Our study suggests a limited role for hyperactive hemostasis in the increased thrombotic risk in NAFLD.

LAY SUMMARY

The combined results of this study show that the overall hemostatic status is comparable between healthy individuals and patients with a fatty liver disease.

Increased risk of portal vein thrombosis in patients with cirrhosis due to nonalcoholic steatohepatitis

Portal vein thrombosis (PVT) is a common complication of cirrhosis sometimes implicated in hepatic decompensation. There are no consistent epidemiologic data to suggest an increased risk of thrombotic complications in nonalcoholic steatohepatitis (NASH); however, research suggests an increased risk of thrombosis. Our aim was to examine the independent association between NASH cirrhosis and PVT in patients who underwent liver transplantation (LT) in a cross-sectional study. Data on all LTs occurring in the United States between January 1, 2003 and December 31, 2012 were obtained from the United Network for Organ Sharing. Multivariable models were constructed to assess the statistical associations and risk factors for the development of PVT. A total of 33,368 patients underwent transplantation. Of these, 2096 (6.3%) had PVT. Of the patients with PVT, 12.0% had NASH. When we compared these patients to a composite of all other causes of cirrhosis, an increased prevalence of PVT was again found, with 10.1% having PVT at the time of transplantation versus 6.0% without NASH (P < 0.001). The strongest risk factor independently associated with a diagnosis of PVT in a multivariable analysis was NASH cirrhosis (odds ratio, 1.55; 95% confidence interval, 1.33-1.81; P < 0.001). NASH cirrhosis appears to predispose a patient to PVT independently of other risk factors. These epidemiological findings provide support for the idea that NASH is a prothrombotic state, and they should lead to more research in treatment and prevention in this population.

Safety and efficacy of pharmacological thromboprophylaxis for hospitalized patients with cirrhosis: a single-center retrospective cohort study

BACKGROUND

Hospitalized patients with cirrhosis are at increased risk for venous thromboembolism (VTE). The benefits and risks of pharmacological thromboprohylaxis in these patients have not been well studied.

OBJECTIVES

To examine the safety and efficacy of pharmacological VTE prophylaxis in hospitalized cirrhotic patients.

PATIENTS/METHODS

Retrospective cohort study of patients with cirrhosis hospitalized at an academic tertiary care referral center over a 5-year period.

RESULTS

Six hundred hospital admissions accounting for 402 patients were included. VTE prophylaxis was administered during 296 (49%) admissions. Patients receiving VTE prophylaxis were older (59 years vs. 55 years, P < 0.001), had longer lengths of stay (9.6 days vs. 6.8 days, P = 0.002), and lower Model for End-Stage Liver Disease scores (13.2 vs. 16.1, P < 0.001). In-hospital bleeding events (8.1% vs. 5.5%, P = 0.258), gastrointestinal bleeding events (3.0% vs. 3.2% P = 0.52), new VTE events (2.37% vs. 1.65%, P = 0.537), and mortality (8.4% vs. 7.3%, P = 0.599) were similar in the two groups. VTE prophylaxis did not reduce the risk of VTE (odds ratio 0.94, 95% confidence interval 0.23-3.71), and patients receiving unfractionated heparin, but not low molecular weight heparin, were at increased risk for in-hospital bleeding events (odds ratio 2.38, 95% confidence interval 1.15-4.94 vs. 0.87, 0.37-2.05, respectively).

CONCLUSION

The rate of VTE in this cohort of hospitalized cirrhotic patients was low and was unaffected by pharmacological thromboprophylaxis. Unfractionated heparin was associated with an increased risk for in-hospital bleeding, suggesting that if thromboprophylaxis is indicated, low molecular weight heparin may be favored.

Is there a rationale for treatment of chronic liver disease with antithrombotic therapy?

Recent advances in the understanding of the coagulopathy in chronic liver disease have provided a strong support for anticoagulation as a new therapeutic paradigm for patients with cirrhosis. Laboratory studies indicate that the net effect of changes in hemostasis in many patients with chronic liver disease is a hypercoagulable status. In turn, clinical thrombosis is increasingly recognized as a complication of liver disease. When occurring within the liver, thrombosis may even progress the disease course. Exciting preliminary data regarding the potential of low-molecular-weight heparin to slow down the progression of liver disease indicate that this class of drugs may improve outcome without a major increase in bleeding risk. However, this new era for antithrombotic therapy in chronic liver disease is still hindered by a persistent false notion that patients with cirrhosis are "auto-anticoagulated" by their underlying liver disease. In addition, there is insufficient clinical evidence on safety and efficacy of anticoagulant therapy in cirrhosis and the studies conducted so far are limited by small sample sizes, uncontrolled treatment arms, or by their retrospective nature. Finally, a lack of knowledge on how or when to monitor antithrombotic treatment to optimize the risk-benefit ratio has restricted a widespread application of anticoagulant treatment in clinical management algorithms. Nonetheless, by systematically covering possibilities and pitfalls, this review highlights the potential of antithrombotic therapy to improve the quality of life and the clinical outcome of patients with chronic liver disease.

Management of portal vein thrombosis in liver cirrhosis

Portal vein thrombosis (PVT) is a fairly common complication of liver cirrhosis. Importantly, occlusive PVT might influence the prognosis of patients with cirrhosis. Evidence from a randomized controlled trial has shown that anticoagulation can prevent the occurrence of PVT in patients with cirrhosis without prior PVT. Evidence from several case series has also demonstrated that anticoagulation can achieve portal vein recanalization in patients with cirrhosis and PVT. Early initiation of anticoagulation therapy and absence of previous portal hypertensive bleeding might be positively associated with a high rate of portal vein recanalization after anticoagulation. However, the possibility of spontaneous resolution of partial PVT questions the necessity of anticoagulation for the treatment of partial PVT. In addition, a relatively low recanalization rate of complete PVT after anticoagulation therapy suggests its limited usefulness in patients with complete PVT. Successful insertion of a transjugular intrahepatic portosystemic shunt (TIPS) not only recanalizes the thrombosed portal vein, but also relieves the symptomatic portal hypertension. However, the technical difficulty of TIPS potentially limits its widespread application, and the risk and benefits should be fully balanced. Notably, current recommendations regarding the management of PVT in liver cirrhosis are insufficient owing to low-quality evidence.

Future treatments of cirrhosis

Cirrhosis can be sub-classified in clinical stages with distinct differences in prognosis and can even be reversed in some cases with successful etiological treatment. In this article, we review potential future therapies of cirrhosis, mainly focusing in the expansion of indications of currently licensed drugs. We strongly advocate that future therapies should focus on preventing the advent of complications and further progression of liver disease and should involve both primary and secondary care physicians. Such strategies could be based on the combination of currently licensed, relatively safe and inexpensive drugs and such randomized controlled trials should be prioritized in patients with advanced liver disease. The paradigm should be similar to that of prevention in cardiovascular diseases and long-term follow-up trials are needed.

Procoagulant imbalance in patients with non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is characterized by increased risk of cardiovascular events and liver-fibrosis. Both could be explained by a procoagulant-imbalance that was surmised but never directly demonstrated. We investigated 113 patients with varying histological liver damage [steatosis (n=32), steatohepatitis (n=51), metabolic-cirrhosis (n=30)], 54 with alcoholic/viral-cirrhosis and 179 controls.

METHODS

Plasma was evaluated for levels of pro- and anti-coagulants, and for thrombin-generation assessed as endogenous-thrombin-potential (ETP) with and without thrombomodulin or Protac® as protein C activators. The procoagulant-imbalance was defined as ETP-ratio (with-to-without thrombomodulin) or as Protac®-induced-coagulation-inhibition (PICI%). High ETP-ratios or low PICI% indicate resistance to thrombomodulin or Protac® and hence a procoagulant-imbalance.

RESULTS

ETP-ratio increased from controls [0.57 (0.11-0.89)] to steatosis [0.72 (0.33-0.86)] and metabolic-cirrhosis [0.80 (0.57-0.95)], (p<0.001), the latter being comparable to that for alcoholic/viral-cirrhosis [0.80 (0.57-0.95) vs. 0.80 (0.44-0.96)]. Factor VIII (a potent procoagulant for thrombin-generation) increased from steatosis [99% (71-150)] to metabolic-cirrhosis [157% (64-232)], p<0.001. Protein C (a powerful anticoagulant) decreased from steatosis [103% (77-228)] to metabolic-cirrhosis [77 (17-146)], p<0.001. As a consequence, factor VIII-to-protein C ratio increased from steatosis [0.96 (0.36-1.60)] to metabolic-cirrhosis [2.05 (0.81-12.1)], p<0.001 and was correlated with the ETP-ratio (rho=0.543, p<0.001). Similar results were obtained for PICI%. Patients with procoagulant-imbalance detected as ETP-ratio greater or PICI% lower than the median value of controls tended to have a higher risk of metabolic-syndrome, higher intima-media thickness, fibrosis, steatosis or lobular inflammation, all considered clinical manifestations of NAFLD.

CONCLUSION

NAFLD is characterized by a procoagulant-imbalance progressing from the less severe (steatosis) to the most severe form of the disease (metabolic-cirrhosis). This imbalance appears to result from increased factor VIII and reduced protein C and might play a role in the risk of cardiovascular events and liver-fibrosis commonly observed in NAFLD.

Risk of cardiovascular, cardiac and arrhythmic complications in patients with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) has emerged as a public health problem of epidemic proportions worldwide. Accumulating clinical and epidemiological evidence indicates that NAFLD is not only associated with liver-related morbidity and mortality but also with an increased risk of coronary heart disease (CHD), abnormalities of cardiac function and structure (e.g., left ventricular dysfunction and hypertrophy, and heart failure), valvular heart disease (e.g., aortic valve sclerosis) and arrhythmias (e.g., atrial fibrillation). Experimental evidence suggests that NAFLD itself, especially in its more severe forms, exacerbates systemic/hepatic insulin resistance, causes atherogenic dyslipidemia, and releases a variety of pro-inflammatory, pro-coagulant and pro-fibrogenic mediators that may play important roles in the pathophysiology of cardiac and arrhythmic complications. Collectively, these findings suggest that patients with NAFLD may benefit from more intensive surveillance and early treatment interventions to decrease the risk for CHD and other cardiac/arrhythmic complications. The purpose of this clinical review is to summarize the rapidly expanding body of evidence that supports a strong association between NAFLD and cardiovascular, cardiac and arrhythmic complications, to briefly examine the putative biological mechanisms underlying this association, and to discuss some of the current treatment options that may influence both NAFLD and its related cardiac and arrhythmic complications.

Prothrombotic factors in histologically proven nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

An independent role of nonalcoholic fatty liver disease (NAFLD) in the development of cardiovascular disease has been suggested, probably mediated through increased levels of prothrombotic factors. Therefore, we examined whether NAFLD is linked to a prothrombotic state, independently of metabolic risk factors in a large single-center cohort of overweight/obese patients. Patients presenting to the obesity clinic underwent a detailed metabolic and liver assessment, including an extensive panel of coagulation factors. If NAFLD was suspected, a liver biopsy was proposed. A series of 273 consecutive patients (65% female) with a liver biopsy were included (age, 44 ± 0.76 years; body mass index: 39.6 ± 0.40 kg/m(2)). Increase in fibrinogen, factor VIII, and von Willebrand factor and decrease in antithrombin III correlated with metabolic features, but not with liver histology. Levels of plasminogen activator inhibitor-1 (PAI-1) increased significantly with increasing severity of steatosis (P < 0.001), lobular inflammation (P < 0.001), ballooning (P = 0.002), and fibrosis (P < 0.001). Patients with nonalcoholic steatohepatitis had significantly higher PAI-1 values than those with normal liver (P < 0.001). In multiple regression, including anthropometric and metabolic parameters, steatosis remained an independent predictor of PAI-1 levels, explaining, together with fasting C-peptide and waist circumference, 21% of the variance in PAI-1. No consistent correlations with histology were found for the other coagulation factors.

CONCLUSION

In obesity, NAFLD severity independently contributes to the increase in PAI-1 levels, whereas other coagulation factors are unaltered. This finding might, in part, explain the increased cardiovascular risk associated with NAFLD.

Role of anticoagulant therapy in liver disease

Anticoagulant therapy is a cornerstone in the treatment of different liver diseases. In Budd-Chiari syndrome (BCS), survival rates have increased considerably since the introduction of a treatment strategy in which anticoagulation is the treatment of first choice. In all patients diagnosed with acute portal vein thrombosis (PVT), anticoagulant therapy for at least 3 months is indicated. Anticoagulation should also be considered in patients with chronic PVT and a concurrent prothrombotic risk factor. Current evidence suggests that patients with PVT in cirrhosis will benefit from treatment with anticoagulation as well. In severe chronic liver disease the levels of both pro- and anticoagulant factors are decreased, resetting the coagulant balance in an individual patient and making it more prone to deviate to a hypo- or hypercoagulable state. An increased activity of the coagulation cascade is not solely a feature of chronic liver disease; it influences the development of liver fibrosis as well. Several studies in animals and humans have shown that anticoagulation could prevent or improve fibrogenesis and even disease progression in cirrhosis. Anticoagulation is therefore a promising antifibrotic treatment modality.

High ambulatory blood pressure values associated with non-alcoholic fatty liver in middle-aged adults

OBJECTIVE

Nonalcoholic fatty liver and hypertension are associated with metabolic syndrome. Both conditions increase the risk for cardiovascular morbidity. The objective of this study was to analyze whether 24-h blood pressure (BP) levels and nondipping phenomenon associate with hepatic steatosis defined as liver brightness.

METHODS

Twenty-four hour ambulatory BP measurement (ABPM) and liver brightness were investigated in a population-based cohort of 890 hypertensive (n = 433) and normotensive (n = 457) individuals aged 40-60 years. ABPM was recorded using the fully automatic SpaceLabs90207 oscillometric unit.

RESULTS

Fatty liver was associated with male sex, increased alcohol consumption, high BMI, large waist (P < 0.001 for all) and increased prevalence of smoking (P < 0.03). Values of alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), triglycerides and high-sensitivity CRP (hsCRP) were higher and high-density lipoprotein cholesterol lower (P < 0.001 for all) in individuals with fatty liver. After adjustments for BMI, sex and age, fatty liver was associated with 24-h (P < 0.005), daytime (P < 0.02) and night-time (P < 0.005) SBP measurements and DBP at daytime (P < 0.03). The association with nondipping showed only a trend (P = 0.057).

CONCLUSION

Significantly higher ambulatory daytime and night-time SBP levels were seen in individuals with fatty liver. Nondipping does not seem to associate with liver fat. The coexistence of liver fat accumulation and high BP are likely to potentiate the risk for cardiovascular disease.

New therapeutic paradigm for patients with cirrhosis

Cirrhosis is a major health problem, being the 5th cause of death in the U.K. and 12th in the U.S., but 4th in the 45 to 54 age group. Until recently cirrhosis was considered a single and terminal disease stage, with an inevitably poor prognosis. However, it is now clear that 1-year mortality can range from 1% in early cirrhosis to 57% in decompensated disease. As the only treatment for advanced cirrhosis is liver transplantation, what is urgently needed is strategies to prevent transition to decompensated stages. The evidence we present in this review clearly demonstrates that management of patients with cirrhosis should change from an expectant algorithm that treats complications as they occur, to preventing the advent of all complications while in the compensated phase. This requires maintaining patients in an asymptomatic phase and not significantly affecting their quality of life with minimal impairment due to the therapies themselves. This could be achieved with lifestyle changes and combinations of already licensed and low-cost drugs, similar to the paradigm of treating risk factors for cardiovascular disease. The drugs are propranolol, simvastatin, norfloxacin, and warfarin, which in combination would cost £128/patient annually-equivalent to U.S. $196/year. This treatment strategy requires randomized controlled trials to establish improvements in outcomes. In the 21st century, cirrhosis should be regarded as a potentially treatable disease with currently available and inexpensive therapies.

[Anesthesia in the patient with impaired liver function]

We review information on impaired liver function, focusing on concepts relevant to anesthesia and postoperative recovery. The effects of impaired function are analyzed by systems of the body, with attention to the complications the patient with liver cirrhosis may develop according to type of surgery. Approaches to correcting coagulation disorders in the cirrhotic patient are particularly controversial because an increase in volume may be a factor in bleeding owing to increased portal venous pressure and imbalances in the factors that favor or inhibit coagulation. Perioperative morbidity and mortality correlate closely to Child-Pugh class and the score derived from the model for end-stage liver disease (MELD). Patients in Child class A are at moderate risk and surgery is therefore not contraindicated. Patients in Child class C or with a MELD score over 20, on the other hand, are at high risk and should not undergo elective surgical procedures. Abdominal surgery is generally considered to put patients with impaired liver function at high risk because it causes changes in hepatic blood flow and increases intraoperative bleeding because of high portal venous pressures.

Hypercoagulability in cirrhosis: causes and consequences

Decreased levels of most coagulation factors and thrombocytopenia are the main haemostatic abnormalities of cirrhosis. As a consequence, this condition was, until recently, considered as the prototype acquired coagulopathy responsible for bleeding. However, recent evidence suggests that it should, rather, be regarded as a condition associated with normal or even increased thrombin generation. The bleeding events that occur in these patients should, therefore, be explained by the superimposed conditions that frequently occur in this setting. Due to elevated levels of factor VIII (procoagulant driver) in combination with decreased protein C (anticoagulant driver), which are typically found in patients with cirrhosis, a procoagulant imbalance, defined as a partial resistance to the in vitro anticoagulant action of thrombomodulin, can be demonstrated. Whether this in vitro hypercoagulability is truly representative of what occurs in vivo remains to be established. However, the hypothesis that it may have clinical consequences is attractive and deserves attention. The possible consequences that we discuss herein include whether (i) cirrhosis is a condition associated with increased risk of venous thromboembolism or portal vein thrombosis; (ii) the hypercoagulability associated with cirrhosis has any other role outside coagulation (i.e. progression of liver fibrosis); and (iii) anticoagulation should be used in cirrhosis. Although apparently provocative, considering anticoagulation as a therapeutic option in patients with cirrhosis is now supported by a rationale of increasing strength. There may be subgroups of patients who benefit from anticoagulation to treat or prevent thrombosis and to slow hepatic fibrosis. Clinical studies are warranted to explore these therapeutic options.

Genetic modifiers of non-alcoholic fatty liver disease progression

Non-alcoholic fatty liver disease (NAFLD) is now recognised as the most common cause of liver dysfunction worldwide. However, whilst the majority of individuals who exhibit features of the metabolic syndrome including obesity and insulin resistance will develop steatosis, only a minority progress to steatohepatitis, fibrosis and cirrhosis. Subtle inter-patient genetic variations and environment interact to determine disease phenotype and influence progression. A decade after the sequencing of the human genome, the comprehensive study of genomic variation offers new insights into the modifier genes, pathogenic mechanisms and is beginning to suggest novel therapeutic targets. We review the current status of the field with particular focus on advances from recent genome-wide association studies.

Increased coagulation factor VIII, IX, XI and XII activities in non-alcoholic fatty liver disease

BACKGROUND AND AIMS

Obesity and the metabolic syndrome are established risk factors of venous thromboembolism. As most coagulation factors are produced exclusively by the liver and non-alcoholic fatty liver disease (NAFLD) is tightly related to metabolic disorders, we aimed at studying the association of liver fat with various coagulation factor activities.

METHODS

Plasma prothrombin (PT) and activated partial thromboplastin time, activities of vWF:RCo, FVII, FVIII, FIX, FXI, FXII, FXIII, fibrinogen and D-dimer concentrations were measured in 54 subjects with and 44 without NAFLD diagnosed by proton magnetic resonance spectroscopy. Subjects were recruited retrospectively for metabolic studies in our laboratory. The body composition and features of insulin resistance were measured in all subjects.

RESULTS

FVIII (107±30 vs. 84±22%, P<0.001), FIX (110±14 vs. 94±16%, P<0.001), FXI (109±16 vs. 96±19%, P=0.001) and FXII (113±21 vs. 99±32%, P=0.002) activities were consistently elevated in subjects with as compared with those without NAFLD. Liver fat percentage was positively related to FVIII (r=0.28, P=0.005), FIX (r=0.36, P=0.0003), FXI (r=0.29, P=0.004) and FXII (r=0.30, P=0.003) activities, again independent of age, gender and body mass index (BMI). PT%, vWF:RCo activity and fibrinogen were higher in subjects with as compared with those without NAFLD, but this difference disappeared after adjusting for age, gender and BMI.

CONCLUSION

FVIII, FIX, FXI and FXII activities are increased in human NAFLD and correlate with the features of insulin resistance. The relationships between NAFLD and these coagulation factors are independent of age, gender and BMI, suggesting that the fatty liver can contribute to the risk of thrombosis.

Hemostasis and thrombosis in patients with liver disease: the ups and downs

Patients with chronic or acute liver failure frequently show profound abnormalities in their hemostatic system. Whereas routine laboratory tests of hemostasis suggest these hemostatic alterations result in a bleeding diathesis, accumulating evidence from both clinical and laboratory studies suggest that the situation is more complex. The average patient with liver failure may be in hemostatic balance despite prolonged routine coagulation tests, since both pro- and antihemostatic factors are affected, the latter of which are not well reflected in routine coagulation testing. However, this balance may easily tip towards a hypo- or hypercoagulable situation. Indeed, patients with liver disease may encounter both hemostasis-related bleeding episodes as well as thrombotic events. During the 3rd International Symposium on Coagulopathy and Liver disease, held in Groningen, The Netherlands (18-19 September 2009), a multidisciplinary panel of experts critically reviewed the current data concerning pathophysiology and clinical consequences of hemostatic disorders in patients with liver disease. Highlights of this symposium are summarized in this review.