An unbalance between von Willebrand factor and ADAMTS13 in acute liver failure: implications for hemostasis and clinical outcome

Von Willebrand Factor Antigen Improves Risk Stratification for Patients with a Diagnosis of Resectable Hepatocellular Carcinoma

BACKGROUND

Posthepatectomy liver failure (PHLF), complications of portal hypertension, and disease recurrence determine the outcome for hepatocellular carcinoma (HCC) patients undergoing liver resection. This study aimed to evaluate the von Willebrand factor antigen (vWF-Ag) as a non-invasive test for clinically significant portal hypertension (CSPH) and a predictive biomarker for time to recurrence (TTR) and overall survival (OS).

METHODS

The study recruited 72 HCC patients with detailed preoperative workup from a prospective trial (NCT02118545) and followed for complications, TTR, and OS. Additionally, 163 compensated patients with resectable HCC were recruited to evaluate vWF-Ag cutoffs for ruling out or ruling in CSPH. Finally, vWF-Ag cutoffs were prospectively evaluated in an external validation cohort of 34 HCC patients undergoing liver resection.

RESULTS

In receiver operating characteristic (ROC) analyses, vWF-Ag (area under the curve [AUC], 0.828) was similarly predictive of PHLF as indocyanine green clearance (disappearance rate: AUC, 0.880; retention rate: AUC, 0.894), whereas computation of future liver remnant was inferior (AUC, 0.756). Cox-regression showed an association of vWF-Ag with TTR (per 10%: hazard ratio [HR], 1.056; 95% confidence interval [CI] 1.017-1.097) and OS (per 10%: HR, 1.067; 95% CI 1.022-1.113). In the analyses, VWF-Ag yielded an AUC of 0.824 for diagnosing CSPH, with a vWF-Ag of 182% or lower ruling out and higher than 291% ruling in CSPH. Therefore, a highest-risk group (> 291%, 9.7% of patients) with a 57.1% incidence of PHLF was identified, whereas no patient with a vWF-Ag of 182% or lower (52.7%) experienced PHLF. The predictive value of vWF-Ag for PHLF and OS was externally validated.

CONCLUSION

For patients with resectable HCC, VWF-Ag allows for simplified preoperative risk stratification. Patients with vWF-Ag levels higher than 291% might be considered for alternative treatments, whereas vWF-Ag levels of 182% or lower identify patients best suited for surgery.

Evaluating the potential mediating role of ADAMTS13 activity in the relationship between obesity and the severity of COVID-19: A retrospective cohort study

Obesity and low enzyme A disintegrin and metalloproteinase with thrombospondin type-1 motif-13 (ADAMTS13) activity have been linked to poor coronavirus disease 2019 (COVID-19). Given that obesity may influence ADAMTS13 activity, it is feasible; however, it remains unclear whether ADAMTS13 activity acts as a mediator between obesity and COVID-19 outcomes. We investigated the link between body mass index (BMI) and COVID-19 outcomes, using ADAMTS13 activity as a mediator. ADAMTS13 activity was measured in 86 hospitalized COVID-19 patients. BMI, ADAMTS13 activity, and COVID-19 outcomes were assessed. Obese patients had a high odds ratio for low ADAMTS13 levels. When different levels of ADAMTS13 activity were considered, the severity of COVID-19 in obese patients was 4.5 times that in the normal BMI group. Furthermore, increased coagulopathy indicators correlated with low ADAMTS13 activity. Patients with elevated ALT and AST levels showed a 3 to 4-fold increase in the chances of low ADAMTS13 activity (OR:3.19, 95% CI:1.22-8.90, P = .021; OR:2.17, 95% CI:0.91-5.27, P = .082, respectively). When ADAMTS13 activity was considered, obese patients had greater COVID-19 severity and slower viral clearance than those with normal BMI. Low ADAMTS13 activity and impaired liver function are associated with poor COVID-19 outcomes. These findings encourage researchers to use molecular component identification to study the effects of obesity on the von Willebrand factor (VWF)/ADAMTS13 axis, COVID-19 pathogenesis, and outcomes.

Combined metabolomic and proteomic analysis of sepsis related acute liver injury and its pathogenesis research

BACKGROUND

Sepsis-induced acute liver injury is common in patients in intensive care units. However, the exact mechanism of this condition remains unclear. The purpose of this study was to investigate the roles and mechanisms of proteins and metabolites in the liver tissue of mice after sepsis and elucidate the molecular biological mechanisms of sepsis-related liver injury.

METHODS

First, a lipopolysaccharide (LPS)-induced sepsis mouse model was established. Then, according to alanine aminotransferase (ALT) and aspartate aminotransferase (AST) detection in mouse serum and liver histopathological examination (HE) staining, the septic mice were divided into two groups: acute liver injury after sepsis and nonacute liver injury after sepsis. Metabolomics and proteomic analyses were performed on the liver tissues of the two groups of mice to identify significantly different metabolites and proteins. The metabolomics and proteomics results were further analysed to identify the biological indicators and pathogenesis related to the occurrence and development of sepsis-related acute liver injury at the protein and metabolite levels.

RESULTS

A total of 14 differentially expressed proteins and 46 differentially expressed metabolites were identified. Recombinant Erythrocyte Membrane Protein Band 4.2 (Epb42) and adenosine diphosphate (ADP) may be the key proteins and metabolites responsible for sepsis-related acute liver injury, according to the correlation analysis of proteomics and metabolomics. The expression of the differential protein Epb42 was further verified by western blot (WB) detection.

CONCLUSIONS

Our study suggests that the differential protein Epb42 may be key proteins causing sepsis-associated acute liver injury, providing new and valuable information on the possible mechanism of sepsis-associated acute liver injury.

VWF/ADAMTS13 Ratio as a Potential Predictive Biomarker for Acute Kidney Injury Onset in Cirrhosis

AIM

We investigated the von Willebrand factor to ADAMTS13 ratio (von Willebrand factor [VWF]:Ag/ADAMTS13:AC) as a potential biomarker for the outcomes of acute kidney injury (AKI) in liver cirrhosis (LC).

METHODS

This retrospective cross-sectional study included patients with LC who developed AKI (AKI group: n = 91) and patients with LC who did not develop AKI [non-AKI (NAKI) group, n = 91] as a control group. Plasma levels of the von Willebrand factor antigen (Ag) and ADAMTS13 activity (AC) were measured in patients with AKI or NAKI. Moreover, risk factors for onset of AKI, AKI-associated 90-day mortality, and poor AKI treatment response were identified.

RESULTS

The AKI group had a significantly higher VWF:Ag/ADAMTS13:AC than the NAKI group. Values of VWF:Ag/ADAMTS13:AC ≥ 5.7 were identified as risk factors for AKI onset in patients with LC (odds ratio [OR] 2.56; 95% CI 1.26-4.99; p < 0.001). Among patients with AKI, values of VWF:Ag/ADAMTS13:AC ≥ 9.0 were identified as risk factors for 90-day mortality (OR 6.83; 95% CI 2.32-20.10; p < 0.001). Cumulative survival was significantly lower in those with high (≥ 9.0) than in those with low (< 9.0) VWF:Ag/ADAMTS13:AC. Furthermore, values of VWF:Ag/ADAMTS13:AC ≥ 7.4 were identified as risk factors for poor treatment response (OR 4.2; 95% CI 1.39-12.70; p < 0.001). The treatment response rates were significantly higher in those with low (< 7.4) VWF:Ag/ADAMTS13:AC than in those with high (≥ 7.4) VWF:Ag/ADAMTS13:AC.

CONCLUSION

VWF:Ag/ADAMTS13:AC potentially predicts the onset, prognosis, and treatment response of AKI in patients with LC.

Serum/Plasma Proteome in Non-Malignant Liver Disease

The liver is the central metabolic organ and produces 85-90% of the proteins found in plasma. Accordingly, the plasma proteome is an attractive source of liver disease biomarkers that reflects the different cell types present in this organ, as well as the processes such as responses to acute and chronic injury or the formation of an extracellular matrix. In the first part, we summarize the biomarkers routinely used in clinical evaluations and their biological relevance in the different stages of non-malignant liver disease. Later, we describe the current proteomic approaches, including mass spectrometry and affinity-based techniques, that allow a more comprehensive assessment of the liver function but also require complex data processing. The many approaches of analysis and interpretation and their potential caveats are delineated. While these advances hold the promise to transform our understanding of liver diseases and support the development and validation of new liver-related drugs, an interdisciplinary collaboration is needed.

The Role of the von Willebrand Factor Collagen-Binding Assay (VWF:CB) in the Diagnosis and Treatment of von Willebrand Disease (VWD) and Way Beyond: A Comprehensive 36-Year History

The von Willebrand factor (VWF) collagen binding (VWF:CB) assay was first reported for use in von Willebrand diagnostics in 1986, by Brown and Bosak. Since then, the VWF:CB has continued to be used to help diagnose von Willebrand disease (VWD) (correctly) and also to help assign the correct subtype, as well as to assist in the monitoring of VWD therapy, especially desmopressin (DDAVP). However, it is important to recognize that the specific value of any VWF:CB is predicated on the use of an optimized VWF:CB, and that not all VWF:CB assays are so optimized. There are some good commercial assays available, but there are also some "not-so-good" commercial assays available, and these may continue to give the VWF:CB "a bad reputation." In addition to VWD diagnosis and management, the VWF:CB found purpose in a variety of other applications, from assessing ADAMTS13 activity, to investigation into acquired von Willebrand syndrome (especially as associated with use of mechanical circulatory support or cardiac assist devices), to assessment of VWF activity in disease states in where an excess of high-molecular-weight VWF may accumulate, and lead to increased (micro)thrombosis risk (e.g., coronavirus disease 2019, thrombotic thrombocytopenic purpura). The VWF:CB turns 37 in 2023. This review is a celebration of the utility of the VWF:CB over this nearly 40-year history.

Laboratory investigation and diagnosis of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a rare and potentially fatal disease for which rapid diagnosis is crucial for patient outcomes. Deficient activity (< 10%) of the liver enzyme, ADAMTS13, is the pathophysiological hallmark of TTP, and measurement of the enzyme activity can establish the diagnosis of TTP with high accuracy. Thus, along with the clinical history, appropriate laboratory assessment of a suspected case of TTP is essential for diagnosis and treatment. Here, we present a review of the available laboratory tests that can assist clinicians in establishing the diagnosis of TTP, with special focus on ADAMTS13 assays, including the measurement of the antigen and activity, and detection of autoantibodies to ADAMTS13.

Von Willebrand factor is an independent predictor of short-term mortality in acutely ill patients with cirrhosis

BACKGROUND AND AIMS

Levels of von Willebrand factor (VWF) are elevated in patients with cirrhosis, and correlate well with disease severity. In patients with decompensated cirrhosis (DC), plasma VWF is associated with mortality. The value of VWF in predicting short-term mortality risk in patients with acute-on-chronic liver failure (ACLF) is, however, unclear.

METHODS

We included patients with DC (n = 111) and ACLF (n = 105). We measured VWF levels and correlated these with other laboratory parameters and prediction models for mortality. Also, we assessed the predictive value of VWF in the prediction of 90- and 30-day mortality in patients with DC and ACLF, respectively, and compared this to the predictive value of clinically used prediction models. Finally, we determined the optimal cut-off value for VWF in patients with ACLF.

RESULTS

Sixteen of 111 (14%) patients with DC and 35 of 105 (33%) with ACLF died within 90 and 30 days, respectively. VWF was associated with mortality and correlated closely with other prediction models. In patients with ACLF, VWF levels had a discrimination for 30-day mortality comparable with these models and accurately identified ACLF patients with high 30-day mortality risk.

CONCLUSIONS

Levels of VWF associate closely with risk of mortality in patients with DC and ACLF, and may have predictive utility as a laboratory marker of prognosis. Further research is warranted to assess the additional value of VWF in the prediction of mortality and associated complications in chronic liver failure syndromes.

Von Willebrand Factor as a Biomarker for Liver Disease - An Update

The von Willebrand factor (vWF) is best known for its role in the hemostatic pathway, aiding platelet adhesion and aggregation, as well as circulating along with coagulation factor VIII, prolonging its half-life. However, vWF is more than a hemostatic protein and is a marker of endothelial dysfunction in patients with cirrhosis. The levels of vWF increase progressively as cirrhosis progresses. Despite its qualitative defects, it can support and carry out its hemostatic role and contribute to a pro-coagulant disbalance. Moreover, it has been shown to be a good noninvasive marker for predicting clinically significant portal hypertension (CSPH). The vWF has been shown to predict decompensation and mortality among cirrhosis patients independently of the stage of liver disease and severity of portal hypertension. Increased vWF levels in the setting of endothelial injury predict bacterial translocation and systemic inflammation. The vWF-to-thrombocyte ratio (VITRO) score adds to the diagnostic ability of vWF alone in detecting CSPH non-invasively. Not only have vWF levels been shown to help predict the risk of hepatocellular carcinoma (HCC) among cirrhosis patients, but they also predict the risk of complications post-resection for HCC and response to systemic therapies. vWF-induced portal microthrombi have been purported to contribute to the pathogenesis of acute liver failure progression as well as non-cirrhotic portal hypertension. The prospect of modulation of vWF levels using drugs such as non-selective beta-blockers, statins, anticoagulants, and non-absorbable antibiotics and its use as a predictive biomarker for the response to these drugs needs to be explored.

Robust coagulation activation and coagulopathy in mice with experimental acetaminophen-induced liver failure

BACKGROUND

Patients with acetaminophen (APAP)-induced acute liver failure (ALF) display both hyper- and hypocoagulable changes not necessarily recapitulated by standard hepatotoxic doses of APAP used in mice (eg, 300 mg/kg).

OBJECTIVES

We sought to examine coagulation activation in vivo and plasma coagulation potential ex vivo in experimental settings of APAP-induced hepatotoxicity and repair (300-450 mg/kg) and APAP-induced ALF (600 mg/kg) in mice.

RESULTS

APAP-induced ALF was associated with increased plasma thrombin-antithrombin complexes, decreased plasma prothrombin, and a dramatic reduction in plasma fibrinogen compared with lower APAP doses. Hepatic fibrin(ogen) deposits increased independent of APAP dose, whereas plasma fibrin(ogen) degradation products markedly increased in mice with experimental ALF. Early pharmacologic anticoagulation (+2 hours after 600 mg/kg APAP) limited coagulation activation and reduced hepatic necrosis. The marked coagulation activation evident in mice with APAP-induced ALF was associated with a coagulopathy detectable ex vivo in plasma. Specifically, prolongation of the prothrombin time and inhibition of tissue factor-initiated clot formation were evident even after restoration of physiological fibrinogen concentrations. Plasma endogenous thrombin potential was similarly reduced at all APAP doses. Interestingly, in the presence of ample fibrinogen, ∼10 times more thrombin was required to clot plasma from mice with APAP-induced ALF compared with plasma from mice with simple hepatotoxicity.

CONCLUSION

The results indicate that robust pathologic coagulation cascade activation in vivo and suppressed coagulation ex vivo are evident in mice with APAP-induced ALF. This unique experimental setting may fill an unmet need as a model to uncover mechanistic aspects of the complex coagulopathy of ALF.

Impact of the von Willebrand factor-ADAMTS-13 axis on the risk of future venous thromboembolism

BACKGROUND

von Willebrand factor (VWF) and its cleaving protease, ADAMTS-13, form a pivotal axis that regulates hemostasis. However, the role of the VWF-ADAMTS-13 axis in the risk of future venous thromboembolism (VTE) is unknown.

OBJECTIVES

To investigate whether plasma ADAMTS-13 levels and an imbalance with VWF levels, assessed as the VWF/ADAMTS-13 ratio, are associated with the risk of future VTE.

PATIENTS/METHODS

A population-based nested case-control study, comprising 383 incident VTE cases and 780 age- and sex-matched controls, was derived from the Tromsø study cohort (1994-2007). Antigen levels of ADAMTS-13 and VWF were measured in plasma samples obtained at cohort baseline. Odds ratios (ORs) with 95% CIs were estimated according to quartile cutoffs of ADAMTS-13 and VWF/ADAMTS-13 ratio determined in controls.

RESULTS

In age- and sex-adjusted analysis, ADAMTS-13 levels were inversely associated with the VTE risk, with an OR of 1.40 (95% CI, 0.99-1.99) for the lowest vs highest quartiles. The VWF/ADAMTS-13 ratio was linearly associated with the VTE risk (P for trend = .001), with an OR of 1.70 (95% CI, 1.19-2.43) for the highest vs lowest quartiles, and the association was particularly pronounced for unprovoked VTE (OR, 2.81; 95% CI, 1.65-4.81). The ORs were only slightly attenuated after additional adjustments for body mass index and C-reactive protein.

CONCLUSIONS

Lowered ADAMTS-13 levels and an imbalance between ADAMTS-13 and VWF levels, reflected by an increased VWF/ADAMTS-13 ratio, were associated with an increased risk of future VTE. Our findings suggest that the VWF-ADAMTS-13 axis is involved in the pathogenesis of VTE.

Transfusion Strategies in the 21st Century: A Case-Based Narrative Report

The transfusion of all blood components (red blood cells, plasma, and platelets) has been associated with increased morbidity and mortality in children. It is essential that pediatric providers weigh the risks and benefits before transfusing a critically ill child. A growing body of evidence has demonstrated the safety of restrictive transfusion practices in critically ill children.

Left-Sided Prosthetic Valve Dysfunction and Gastrointestinal Bleeding

Introduction We sought to investigate the association between left-sided prosthetic valve dysfunction and gastrointestinal (GI) bleeding. Methods In a retrospective cohort of patients with left-sided prostheses, we identified those who experienced one or more GI bleeds. The latest or chronologically closest echocardiogram to the GI bleed was analyzed by a blinded investigator for prosthetic valve dysfunction. Results Among 334 unique patients, 166 had aortic prostheses, 127 had mitral prostheses, and 41 had both. A total of 58 (17.4%) subjects had GI bleeding events. Patients in the "GI Bleed" group had higher mean ejection fraction (56±14% vs. 49±15%; P = 0.003) and higher prevalence of hypertension, end-stage renal disease, and liver cirrhosis compared to the "No GI Bleed" group. There was a higher prevalence of moderate or severe prosthetic valve regurgitation in the GI Bleed vs. No GI Bleed group (8.6% vs. 2.2%; P = 0.027). Moderate or severe prosthetic valve regurgitation was independently associated with GI bleeding (odds ratio, 6.18; 95% confidence interval, 1.27-30.05; P = 0.024), after adjusting for ejection fraction, hypertension, end-stage renal disease and liver cirrhosis. Paravalvular regurgitation was associated with a higher incidence of GI bleeding compared to transvalvular regurgitation (35.7% vs. 11.9%; P = 0.044). The prevalence of prosthetic valve stenosis was similar between the GI Bleed and No GI Bleed groups (6.9% vs. 5.8%; P = 0.761). Conclusion In a cohort of patients with predominantly surgically placed prosthetic valves, moderate to severe left-sided prosthetic valve regurgitation was independently associated with GI bleeding.

Administration of spermidine attenuates concanavalin A-induced liver injury

A previous study revealed that treatment with the anticoagulant heparin attenuated concanavalin A (ConA)-induced liver injury. The administration of spermidine (SPD) increased urokinase-type plasminogen activator (uPA) levels in the serum. uPA is clinically used for the treatment of some thrombotic diseases such as cerebral infarction. Therefore, SPD may attenuate ConA-induced liver injury that is exacerbated by blood coagulation. The present study investigated the effect of SPD on liver injury in mice with autoimmune hepatopathy induced by ConA. A model of liver injury was created by intravenous injection of ConA into mice. SPD was administered in free drinking water and was biochemically and pathologically examined over time. The administration of SPD to ConA-treated mice significantly reduced liver injury. However, SPD treatment upregulated the mRNA expression of TNF-α and IFN-ϒ in the livers of ConA-treated mice. In contrast, the mRNA expression of tissue factor in the livers of SPD-treated mice was decreased after ConA injection. The frequency of lymphocytes and lymphocyte activation were not affected by SPD administration in ConA-treated mice. SPD treatment increased uPA levels in the serum and decreased the level of D-dimer in ConA-treated mice. Moreover, SPD decreased fibrin in the livers of ConA-treated mice. These results indicated that SPD treatment increased anticoagulant ability by increasing of uPA and attenuated ConA-induced liver injury.

The Ratio of von Willebrand Factor Antigen to ADAMTS13 Activity: Usefulness as a Prognostic Biomarker in Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) has a high risk of short-term mortality. A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) is a metalloproteinase that specifically cleaves multimeric von Willebrand factor (VWF). Imbalance between ADAMTS13 and VWF is associated with portal hypertension, which induces ACLF development. A previous study reported that ADAMTS13 activity (ADAMTS13:AC) and VWF antigen (VWF:Ag) are predictive biomarkers of ACLF development in patients with cirrhosis. This study investigated the changes in ADAMTS13:AC and VWF:Ag levels from before to after the development of ACLF to determine their usefulness as a prognostic biomarker in patients with ACLF. In total, 101 patients with cirrhosis were enrolled in this study. The level of ADAMTS13:AC and VWF:Ag was determined by an enzyme-linked immunosorbent assay. Cox proportional hazard regression analysis was conducted to determine independent prognostic factors for patients with liver cirrhosis in the post-ACLF group. ADAMTS13:AC levels gradually decreased in the order of non-ACLF group, pre-ACLF group, and finally post-ACLF group. VWF:Ag and the ratio of VWF:Ag to ADAMTS13:AC (VWF:Ag/ADAMTS13:AC) levels gradually increased in the order of non-ACLF group, pre-ACLF group, followed by post-ACLF group. VWF:Ag/ADAMTS13:AC and CLIF-C ACLF scores were associated with prognosis in the post-ACLF group in multivariate analysis. The cumulative survival of the post-ACLF group was significantly lower for patients with high VWF:Ag/ADAMTS13:AC (>9) compared with those with low VWF:Ag/ADAMTS13:AC (≤9) (HR: 10.72, 95% confidence interval: 1.39-82.78, p < 0.05). The VWF:Ag/ADAMTS13:AC increased according to the progression of ACLF in patients with cirrhosis and predicted prognosis in patients with cirrhosis with ACLF.

Nutritional Support in Acute Liver Failure

Acute liver failure (ALF) presents with an acute abnormality of liver blood tests in an individual without underlying chronic liver disease. The clinical course leads to the development of coagulopathy and hepatic encephalopathy. The role of nutrition in its prevention and treatment remains uncertain. We aimed to review literature data on the concept of ALF and the role of nutrition in its treatment and prevention, considering the impact of gut microbiota dysbiosis and eubiosis. We conducted a review of the literature on the main medical databases using the following keywords and acronyms and their associations: liver failure, nutrition, branched-chain amino acids, gut microbiota, dysbiosis, and probiotics. Upon their arrival at the emergency department, an early, accurate nutritional assessment is crucial for individuals with ALF. Branched-chain amino acids (BCAAs), stable euglycemia maintenance, and moderate caloric support are crucial for this subset of patients. An excessive protein load must be avoided because it worsens hepatic encephalopathy. Preclinical evidence supports future probiotics use for ALF treatment/prevention. Nutritional support and treatment for ALF are crucial steps against patient morbidity and mortality. BCAAs and euglycemia remain the mainstay of nutritional treatment of ALF. Gut dysbiosis re-modulation has an emerging and natural-history changing impact on ALF.

Ancient Herbal Formula Mahuang Lianqiao Chixiaodou Decoction Protects Acute and Acute-on-Chronic Liver Failure via Inhibiting von Willebrand Factor Signaling

BACKGROUND

Acute liver failure (ALF) and acute-on-chronic liver failure (ACLF) are characterized by systemic inflammation and high mortality, but there is no effective clinical treatment. As a classic traditional Chinese medicine (TCM) formula, MaHuang-LianQiao-ChiXiaoDou decoction (MHLQD) has been used clinically for centuries to treat liver diseases.

METHODS

The LPS/D-GalN-induced ALF mice model and the CCl4+LPS/D-GalN-induced ACLF mice model were used to observe the therapeutic effects of MHLQD on mice mortality, hepatocytes death, liver injury, and immune responses.

RESULTS

MHLQD treatment significantly improved mice mortality. Liver injury and systemic and hepatic immune responses were also ameliorated after MHLQD treatment. Mechanistically, proteomic changes in MHLQD-treated liver tissues were analyzed and the result showed that the thrombogenic von Willebrand factor (VWF) was significantly inhibited in MHLQD-treated ALF and ACLF models. Histological staining and western blotting confirmed that VWF/RAP1B/ITGB3 signaling was suppressed in MHLQD-treated ALF and ACLF models. Furthermore, mice treated with the VWF inhibitor ADAMTS13 showed a reduced therapeutic effect from MHLQD treatment.

CONCLUSIONS

Our study indicated that MHLQD is an effective herbal formula for the treatment of ALF and ACLF, which might be attributed to the protection of hepatocytes from death via VWF/RAP1B/ITGB3 signaling.

A look into hemostatic characteristics during pediatric liver transplantation using the thromboelastometry (ROTEM® ) test

There is a paucity of evidence about the coagulation profile regarding the complexity of children undergoing liver transplantation (LT). This study aimed to investigate intraoperative hemostatic changes during pediatric LT according to the etiology for LT and examine the ability of rotational thromboelastometry (ROTEM^® , TEM International GmbH, Munich, Germany) as a point-of-care monitoring method. We evaluated 106 patients aged 3 months to 17 years undergoing LT for acute liver failure (ALF) and chronic liver disease, which consists of patients with cholestatic disease, metabolic/genetic disease, and cancer. A total of 731 ROTEM^® measurements, including 301 ellagic acid to initiate clotting via the intrinsic pathway, 172 tissue factor to initiate the extrinsic clotting cascade (EXTEM), and 258 cytochalasin D to inhibit platelet activity reflecting fibrinogen (FIBTEM), were analyzed at predetermined time points (the preanhepatic, anhepatic, and postreperfusion phases). We simultaneously conducted conventional coagulation tests. In children with ALF, preanhepatic measurements of conventional coagulation tests and ROTEM^® showed a more hypocoagulable state than other diseases. During LT, the coagulation profile was deranged, with a prolonged clotting time and reduced clot firmness, changes that were more profound in the cholestatic disease group. Maximum clot firmness (MCF) on EXTEM and FIBTEM were well correlated with the platelet count and fibrinogen concentration (r = 0.830, p < 0.001 and r = 0.739, p < 0.001, respectively). On the EXTEM, MCF with 30 mm predicted a platelet count <30,000/mm³ (area under the curve, 0.985), and 6 mm predicted a fibrinogen concentration <100 mg/dl on the FIBTEM (area under the curve, 0.876). However, the activated partial thromboplastin time and prothrombin time were significant but only weakly correlated with the clotting time on the ROTEM^® . In children undergoing LT, coagulation profiles depend on the etiology for LT. During LT, ROTEM^® parameters could help detect thrombocytopenia and hypofibrinogenemia and guide transfusion therapy as a point-of-care monitoring method.

Transfusion Strategies for Hemostatic Blood Products in Critically Ill Children: A Narrative Review and Update on Expert Consensus Guidelines

Critically ill children commonly receive coagulant products (plasma and/or platelet transfusions) to prevent or treat hemorrhage or correct coagulopathy. Unique aspects of pediatric developmental physiology, and the complex pathophysiology of critical illness must be considered and balanced against known transfusion risks. Transfusion practices vary greatly within and across institutions, and high-quality evidence is needed to support transfusion decision-making. We present recent recommendations and expert consensus statements to direct clinicians in the decision to transfuse or not to transfuse hemostatic blood products, including plasma, platelets, cryoprecipitate, and recombinant products to critically ill children.

Anticoagulation in thrombocytopenic patients - Time to rethink?

One of the difficult clinical situations in the anticoagulation era is how to give these medications to patients with significantly reduced platelet counts. The concern is the heightened bleeding risk, and the current practice is to apply a certain platelet count threshold below which the use of anticoagulant is deemed unsafe. However, this is not an evidence-based approach especially because the thresholds arose from studies in patients with acute leukemia. In this forum article, we discuss the bleeding risk estimation in thrombocytopenic patients when the decreased counts may not be related to marrow underproduction and aim to identify possible markers which can help in this risk estimation beyond platelet counts. We exhort future studies to include a combination of these markers, which may then guide us to administer safe anticoagulation in patients with severe thrombocytopenia.

Management of Decompensated Cirrhosis in the Surgical ICU: an American Association for the Surgery of Trauma Critical Care Committee Clinical Consensus Document

Management of decompensated cirrhosis (DC) can be challenging for the surgical intensivist. Management of DC is often complicated by ascites, coagulopathy, hepatic encephalopathy, gastrointestinal bleeding, hepatorenal syndrome, and difficulty assessing volume status. This Clinical Consensus Document created by the American Association for the Surgery of Trauma Critical Care Committee reviews practical clinical questions about the critical care management of patients with DC to facilitate best practices by the bedside provider.

Haemostatic alterations and management of haemostasis in patients with cirrhosis

Patients with cirrhosis frequently acquire complex changes in their haemostatic system including a decreased platelet count and decreased levels of various haemostatic proteins. Although historically patients with cirrhosis were thought to have a haemostasis-related bleeding tendency, it is now widely accepted that the haemostatic system of patients with cirrhosis remains in balance as a result of simultaneous changes in pro- and anti-haemostatic systems. The concept of rebalanced haemostasis has led to changes in clinical management, although firm evidence from well-designed clinical studies is largely lacking. For example, many invasive procedures in patients with cirrhosis and a prolonged prothrombin time are now performed without prophylaxis with fresh frozen plasma. Conversely, clinicians have become more aware of the need for anti-thrombotic therapy, even in those patients with abnormal routine coagulation tests. This paper will outline recent advances in pathogenesis, prevention and treatment of both bleeding and thrombotic complications in patients with cirrhosis. Among other topics, we will discuss the haemostatic status of acutely ill patients with cirrhosis, the various causes of bleeding in patients with cirrhosis, and how best to prevent or treat bleeding. In addition, we will discuss the hypercoagulable features of patients with cirrhosis, new insights into the pathogenesis of portal vein thrombosis, and how best to prevent or treat thromboses.

Pathophysiology and management of bleeding and thrombosis in patients with liver disease

Patients with liver disease often develop complex changes in their haemostatic system. Frequently observed changes include thrombocytopaenia and altered plasma levels of most of the proteins involved in haemostasis. Although liver disease was historically classified as a haemostasis‐related bleeding disorder, it has now been well established that the antihaemostatic changes that promote bleeding are compensated for by prohaemostatic changes. Conventional coagulation tests however do not accurately reflect these prohaemostatic changes, resulting in an underestimation of haemostatic potential. Novel coagulation tests, such as viscoelastic tests (VETs) and thrombin generation assays (TGAs) better reflect the net result of the haemostatic changes in patients with liver disease, and demonstrate a new, “rebalanced” haemostatic status. Although rebalanced, this haemostatic status is more fragile than in patients without liver disease. Patients with liver disease are therefore not only at risk of bleeding but also at risk of thrombosis. Notably, however, many haemostatic complications in liver disease are not related to the haemostatic failure. It is, therefore, crucial to identify the cause of the bleed or thrombotic complication in order to provide adequate treatment. In this paper, we will elaborate on the haemostatic changes that occur in liver disease, reflect on laboratory and clinical studies over the last few years, and explore the pathophysiologies of bleeding and thrombosis in this specific patient group.

Acute liver failure

PURPOSE OF REVIEW

Present an outline of acute liver failure, from its definition to its management in critical care, updated with findings of selected newer research.

RECENT FINDINGS

Survival of patients with acute liver failure has progressively improved. Intracranial hypertension complicating hepatic encephalopathy is now much less frequent than in the past and invasive ICP monitoring is now rarely used. Early renal replacement therapy and possibly therapeutic plasma exchange have consolidated their role in the treatment. Further evidence confirms the low incidence of bleeding in these patients despite striking abnormalities in standard tests of coagulation and new findings of abnormalities on thromboelastographic testing. Specific coagulopathy profiles including an abnormal vWF/ADAMTS13 ratio may be associated with poor outcome and increased bleeding risk. Use of N-acetylcysteine in nonparacetamol-related cases remains unsupported by robust clinical evidence. New microRNA-based prognostic markers to select patients for transplantation are described but are still far from widespread clinical applicability; imaging-based prognostication tools are also promising. The use of extracorporeal artificial liver devices in clinical practice is yet to be supported by evidence.

SUMMARY

Medical treatment of patients with acute liver failure is now associated with significantly improved survival. Better prognostication and selection for emergency liver transplant may further improve care for these patients.

Ratio of von Willebrand factor antigen to ADAMTS13 activity is a useful biomarker for acute-on-chronic liver failure development and prognosis in patients with liver cirrhosis

AIM

Acute-on-chronic liver failure (ACLF) is associated with a high risk of short-term mortality after progression to multiple organ failure. A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) is a metalloproteinase that specifically cleaves multimeric von Willebrand factor (VWF). An imbalance between ADAMTS13 enzyme and VWF substrate is associated with liver cirrhosis progression that induces ACLF. This study examined the relationship between ADAMTS13 and VWF and ACLF development to determine whether ADAMTS13 and VWF are useful predictive biomarkers for ACLF development and prognosis of patients with liver cirrhosis.

METHODS

The study enrolled 67 patients with Child-Pugh class A and B liver cirrhosis. ADAMTS13 activity (ADAMTS13:AC) and VWF antigen (VWF:Ag) were measured using enzyme-linked immunosorbent assays. The ratio of VWF:Ag to ADAMTS13:AC (VWF:Ag/ADAMTS13:AC) was used to divide patients into two groups according to the classification and regression tree based on Gray model survival analysis.

RESULTS

Compared with patients with Child-Pugh class A liver cirrhosis, class B patients had a higher VWF:Ag/ADAMTS13:AC and a higher risk of ACLF development. Cumulative incidence of ACLF was significantly higher in patients with high (>7.9) versus low (≤7.9) VWF:Ag/ADAMTS13:AC (hazard ratio [HR], 6.50; 95% CI, 2.31-18.29; p < 0.001). Cumulative survival was significantly lower in cirrhotic patients with high versus low VWF:Ag/ADAMTS13:AC (HR 5.11; 95% CI, 1.85-14.14; p = 0.002).

CONCLUSIONS

For patients with liver cirrhosis, VWF:Ag/ADAMTS13:AC is associated with functional liver reserve and predicts the development of ACLF and the prognosis.

ADAMTS13, VWF, and Endotoxin Are Interrelated and Associated with the Severity of Liver Cirrhosis via Hypercoagulability

ADAMTS13 specifically cleaves the multimeric von Willebrand factor (VWF), and an imbalance between ADAMTS13 activity (ADAMTS13:AC) and VWF antigen (VWF:Ag) levels is associated with the severity of liver cirrhosis (LC). However, the reason for this imbalance in patients with LC is unknown. This study investigated the relationship among ADAMTS13:AC, VWF:Ag, and endotoxin (Et) levels in patients with LC. ADAMTS13:AC and VWF:Ag levels were determined using ELISA, whereas Et levels were estimated using a chromogenic substrate assay. The levels of ADAMTS13 inhibitor (ADAMTS13:INH) were evaluated by measuring the extent that heat-inactivated patient’s plasma reduces the ADAMTS13:AC of the control. The status (degraded, normal, or unusually large [UL]) of the VWF multimer (VWFM) was determined through vertical agarose gel electrophoresis. ADAMTS13:AC, VWF:Ag, and Et levels decreased, increased, and increased, respectively, with the severity of LC. Patients with cirrhosis with high Et levels had lower and higher ADAMTS13:AC and VWF:Ag levels, respectively, than those with low Et levels. Patients with cirrhosis with detectable ADAMTS13:INH had higher Et levels than those with undetectable ADAMTS13:INH. Patients whose VWFM was either normal or UL had higher Et levels than those with degraded VWFM. In conclusion, ADAMTS13, VWF, and Et may be interrelated and associated with the severity of LC via hypercoagulability.

Comparison of the Efficacy and Safety of Direct Oral Anticoagulants and Vitamin K Antagonists in Patients with Atrial Fibrillation and Concomitant Liver Cirrhosis: A Systematic Review and Meta-Analysis

BACKGROUND

Patients with atrial fibrillation (AF) have a higher risk of developing thromboembolic events. Current guidelines recommend the use of oral anticoagulants for stroke prevention in these patients. Several clinical trials demonstrated that direct oral anticoagulants (DOACs) have similar efficacy and are safer alternatives to traditional oral anticoagulants. However, patients with concomitant liver cirrhosis were excluded from these trials.

OBJECTIVE

We aimed to systematically identify and review published clinical studies on the use of DOACs in patients with AF and liver cirrhosis and assess the efficacy and safety of DOACs in these patients.

METHODS

A systematic review of clinical trials and retrospective studies was conducted by searching the PubMed, Cochrane Library, Embase, SCOPUS, and Web of Science databases up to September 2020.

RESULTS

Three retrospective studies were included, involving 4011 patients with AF and liver cirrhosis. The use of DOACs was associated with a significant reduction in ischemic stroke (hazard ratio [HR] 0.62; 95% confidence interval [CI] 0.42-0.90; p = 0.01), major bleeding events (HR 0.64; 95% CI 0.57-0.72; p < 0.001), and intracranial hemorrhage (HR 0.49; 95% CI 0.40-0.59; p < 0.001).

CONCLUSIONS

Compared with warfarin in patients with AF and liver cirrhosis, DOACs appear to be associated with improved efficacy and safety outcomes. Randomized controlled trials are warranted to confirm these findings.

Proceedings of ESPGHAN Monothematic Conference 2020: "Acute Liver Failure in Children": Diagnosis and Initial Management

OBJECTIVES

The Hepatology Committee of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) aims to educate pediatric gastroenterologists, members of ESPGHAN and professionals from other specialties promoting an exchange of clinical expertise in the field of pediatric hepatology. Herewith we have concentrated on detailing the recent advances in acute liver failure in infants and children.

METHODS

The 2020 ESPGHAN monothematic three-day conference on pediatric hepatology disease, entitled "acute liver failure" (ALF), was organized in Athens, Greece. ALF is a devastating disease with high mortality and most cases remain undiagnosed. As knowledge in diagnosis and treatment of ALF in infants and children has increased in the past decades, the objective was to update physicians in the field with the latest research and developments in early recognition, curative therapies and intensive care management, imaging techniques and treatment paradigms in these age groups.

RESULTS

In the first session, the definition, epidemiology, various causes of ALF, in neonates and older children and recurrent ALF (RALF) were discussed. The second session was dedicated to new aspects of ALF management including hepatic encephalopathy (HE), coagulopathy, intensive care interventions, acute on chronic liver failure, and the role of imaging in treatment and prognosis. Oral presentations by experts in various fields are summarized highlighting key learning points.

CONCLUSIONS

The current report summarizes the major learning points from this meeting. It also identifies areas where there is gap of knowledge, thereby identifying the research agenda for the near future.

Generation of neutrophil extracellular traps in patients with acute liver failure is associated with poor outcome

BACKGROUND AND AIMS

Acute liver failure (ALF) is characterized by significant changes in the hemostatic system and by systemic inflammation. The formation of neutrophil extracellular traps (NETs), in which an activated neutrophil expels its DNA, histones, and granular enzymes, such as myeloperoxidase (MPO), has been associated with immune-mediated and thrombotic diseases. We hypothesized that formation of NETs in patients with ALF contributes to progression of disease.

APPROACH AND RESULTS

A total of 676 patients with ALF (international normalized ratio [INR], ≥1.5) or severe acute liver injury (ALI; INR, ≥2.0) were recruited from the U.S. ALF Study Group Registry between 2011 and 2018, of whom 308 patients (45.6%) had acetaminophen-induced ALF. Up to 21 days after admission, 483 patients (71.5%) survived without liver transplantation (LT). Levels of cell-free DNA (cfDNA) and the specific NET marker MPO-DNA complexes were measured in plasma samples obtained on admission and compared to levels in healthy controls. In addition, liver tissue obtained at transplantation of 20 ALF patients was stained for NETs. Levels of cfDNA were 7.1-fold, and MPO-DNA complexes 2.5-fold, higher in patients with ALF compared to healthy controls. cfDNA levels were not associated with 21-day transplant-free survival, but were higher in those patients with more-severe disease on admission, as reflected by various laboratory and clinical parameters. MPO-DNA levels were 30% higher in patients with ALF who died or required urgent LT. Liver tissue of ALF patients stained positive for NETs in 12 of 18 evaluable patients.

CONCLUSIONS

Here, we provide evidence for NET formation in patients with ALF. Elevated plasma levels of MPO-DNA complexes in patients with ALF were associated with poor outcome, which suggests that NET formation contributes to disease progression.

Effects of Inflammation on Hemostasis in Acutely Ill Patients with Liver Disease

Patients with liver diseases are in a rebalanced state of hemostasis, due to simultaneous decline in pro- and anticoagulant factors. This balance seems to remain even in the sickest patients, but is less stable and might destabilize when patients develop disease complications. Patients with acute decompensation of cirrhosis, acute-on-chronic liver failure, or acute liver failure often develop complications associated with changes in the hemostatic system, such as systemic inflammation. Systemic inflammation causes hemostatic alterations by adhesion and aggregation of platelets, release of von Willebrand factor (VWF), enhanced expression of tissue factor, inhibition of natural anticoagulant pathways, and inhibition of fibrinolysis. Laboratory tests of hemostasis in acutely-ill liver patients may indicate a hypocoagulable state (decreased platelet count, prolongations in prothrombin time and activated partial thromboplastin time, decreased fibrinogen levels) due to decreased synthetic liver capacity or consumption, or a hypercoagulable state (increased VWF levels, hypofibrinolysis in global tests). Whether these changes are clinically relevant and should be corrected with antithrombotic drugs or blood products is incompletely understood. Inflammation and activation of coagulation may cause local ischemia, progression of liver disease, and multiorgan failure. Anti-inflammatory treatment in acutely-ill liver patients may be of potential interest to prevent thrombotic or bleeding complications and halt progression of liver disease.

Efficacy and safety of direct oral anticoagulants versus vitamin K antagonist for portal vein thrombosis in cirrhosis: A systematic review and meta-analysis

INTRODUCTION AND AIM

Portal vein thrombosis (PVT) is associated with a higher risk of liver-related complications. Recent guidelines recommend direct-acting anticoagulants (DOAC) in patients with cirrhosis and non-tumoral PVT. However, data on the efficacy and safety of DOAC in these patients remain limited. We aim to investigate the efficacy and safety of DOAC compared to vitamin K antagonists (VKA) to treat non-tumoral PVT in patients with cirrhosis.

METHODS

We performed a systematic search of six electronic databases using MeSH term and free text. We selected all studies comparing the use of DOACs with vitamin K antagonist to treat PVT in cirrhosis. The primary outcome was PVT recanalization. Secondary outcomes were and PVT progression, major bleeding, variceal bleeding and death.

RESULTS

From 944 citations, we included 552 subjects from a total of 11 studies (10 observational and 1 randomized trial) that fulfilled the inclusion criteria. We found that DOAC were associated with a higher pooled rate of PVT recanalization (RR = 1.67, 95%CI: 1.02, 2.74, I² = 79%) and lower pooled risk of PVT progression (RR = 0.14, 95%CI: 0.03-0.57, I² = 0%). The pooled risk of major bleeding (RR = 0.29, 95%CI: 0.08-1.01, I² = 0%), variceal bleeding (RR = 1.29, 95%CI: 0.64-2.59, I² = 0%) and death (RR = 0.31, 95%CI: 0.01-9.578, I² = 80%) was similar between DOAC and VKA.

CONCLUSION

For the treatment of PVT in patients with cirrhosis, the bleeding risk was comparable between DOAC and VKA. However, DOAC were associated with a higher pooled rate of PVT recanalization. Dedicated randomized studies are needed to confirm these findings.

Gene Signatures Detect Damaged Liver Sinusoidal Endothelial Cells in Chronic Liver Diseases

Liver sinusoidal endothelial cells have a gatekeeper function in liver homeostasis by permitting substrates from the bloodstream into the space of Disse and regulating hepatic stellate cell activation status. Maintenance of LSEC's highly specialized phenotype is crucial for liver homeostasis. During liver fibrosis and cirrhosis, LSEC phenotype and functions are lost by processes known as capillarization and LSEC dysfunction. LSEC capillarization can be demonstrated by the loss of fenestrae (cytoplasmic pores) and the manifestation of a basement membrane. Currently, no protein or genetic markers can clearly distinguish healthy from damaged LSECs in acute or chronic liver disease. Single cell (sc)RNA sequencing efforts have identified several LSEC populations in mouse models for liver disease and in human cirrhotic livers. Still, there are no clearly defined genesets that can identify LSECs or dysfunctional LSEC populations in transcriptome data. Here, we developed genesets that are enriched in healthy and damaged LSECs which correlated very strongly with healthy and early stage- vs. advanced human liver diseases. A damaged LSEC signature comprised of Fabp4/5 and Vwf/a1 was established which could efficiently identify damaged endothelial cells in single cell RNAseq data sets. In LSECs from an acute CCl₄ liver injury mouse model, Fabp4/5 and Vwf/a1 expression is induced within 1-3 days while in cirrhotic human livers these 4 genes are highly enriched in damaged LSECs. In conclusion, our newly developed gene signature of damaged LSECs can be applicable to a wide range of liver disease etiologies, implicating a common transcriptional alteration mechanism in LSEC damage.

Von Willebrand factor exerts hepatoprotective effects in acute but not chronic cholestatic liver injury in mice

Acute and chronic liver disease are associated with substantial alterations in the hemostatic system, including elevated levels of the platelet-adhesive protein von Willebrand factor (VWF). Carbon tetrachloride-induced liver fibrosis is reduced in VWF-deficient mice, but it is unclear if VWF plays a pathologic role in all settings of liver fibrosis. Indeed, several studies suggest an anti-fibrotic role for components of the hemostatic system, including platelets, in experimental settings of bile duct fibrosis. However, the role of VWF in this specific pathology has not been examined. We tested the hypothesis that VWF exerts hepatoprotective effects in experimental bile duct injury. Wild-type and VWF-deficient (VWF^-/-) mice were challenged with the bile duct toxicant alpha-naphthylisothiocyanate (ANIT) and the impact of VWF deficiency on acute cholestatic liver injury and chronic liver fibrosis was determined. Acute ANIT (60 mg/kg, po)-induced cholestatic liver injury was associated with increased VWF plasma antigen and activity levels. VWF deficiency enhanced ANIT-induced hepatocellular injury, evidenced by increased plasma ALT activity and area of hepatocellular necrosis. Surprisingly, platelet accumulation within necrotic areas was increased in ANIT-challenged VWF^-/- mice compared to wild-type mice. Compared to acute ANIT challenge, hepatic platelet accumulation was modest and appeared to be VWF-dependent in mice exposed to ANIT diet (0.05 %) for 6 weeks. However, contrasting the role of VWF after acute ANIT challenge, VWF deficiency did not impact biliary fibrosis induced by chronic ANIT exposure. The results suggest that VWF plays dichotomous roles in experimental acute and chronic ANIT-induced cholestatic liver injury.

Altered von Willebrand Factor and ADAMTS13 Levels in Children With Cirrhosis and Extrahepatic Portal Hypertension

BACKGROUND/AIM

This study was concerned with whether vWF (von Willebrand factor) and a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13) has altered in patients with cirrhosis and extrahepatic portal hypertension (EPH). We aimed to investigate changes to vWF and ADAMTS13 in children with cirrhosis and EPH.

PATIENTS AND METHODS

This study was conducted between January and October 2019 with both cirrhosis and EPH patients and with healthy volunteers. The von Willebrand factor antigen (vWF:Ag), von Willebrand Ristocetin cofactor (vWF:RCo), and ADAMTS13 antigen and activity were studied.

RESULTS

Twenty-eight children with cirrhosis, 16 children with EPH, and 20 healthy controls were included in the study. vWF:Ag and vWF:RCo levels were higher in patients with cirrhosis than in healthy controls (171.65±101.67 vs. 85.86±30.58, P<0.01 and 121.62±55.83 vs. 61.52±27.03, P<0.01, respectively). vWF:Ag and vWF:RCo levels were higher in patients with EPH than in healthy controls (133.93±80.13 vs. 85.86±30.58, P<0.01 and 103.18±58.55 vs. 61.52±27.03, P=0.02, respectively). The ADAMTS13 antigen and activity levels were lower in patients with cirrhosis than in healthy controls (0.58±0.23 vs. 0.97±0.15, P<0.01 and 49.91±22.43 vs. 86.51±22.07, P=0.02, respectively). The ADAMTS13 antigen and activity levels were lower in patients with EPH than in healthy controls (0.69±0.11 vs. 0.97±0.15, P=0.03; and 68.50±13.29 vs. 86.51±22.07, P=0.02, respectively). The increase in vWF and the decrease in ADAMTS13 were more pronounced in cirrhotic patients with autoimmune hepatitis (AIH) than in non-AIH patients.

CONCLUSIONS

While levels of vWF:Ag and vWF:RCo increased in children with cirrhosis and EPH, levels of the ADAMTS13 antigen and ADAMTS13 activity decreased. These alterations were more pronounced in patients with AIH-derived cirrhosis.

The Addition of C-Reactive Protein and von Willebrand Factor to Model for End-Stage Liver Disease-Sodium Improves Prediction of Waitlist Mortality

BACKGROUND AND AIMS

Patients with cirrhosis on the liver transplant (LT) waiting list may die or be removed because of complications of portal hypertension (PH) or infections. von Willebrand factor antigen (vWF-Ag) and C-reactive protein (CRP) are simple, broadly available markers of these processes.

APPROACH AND RESULTS

We determined whether addition of vWF-Ag and CRP to the Model for End-Stage Liver Disease-Sodium (MELD-Na) score improves risk stratification of patients awaiting LT. CRP and vWF-Ag at LT listing were assessed in two independent cohorts (Medical University of Vienna [exploration cohort] and Mayo Clinic Rochester [validation cohort]). Clinical characteristics, MELD-Na, and mortality on the waiting list were recorded. Prediction of 3-month waiting list mortality was assessed by receiver operating characteristics curve (ROC-AUC). In order to explore potential mechanisms underlying the prognostic utility of vWF-Ag and CRP in this setting, we evaluated their association with PH, bacterial translocation, systemic inflammation, and circulatory dysfunction. In the exploration cohort (n = 269) vWF-Ag and CRP both improved the predictive value of MELD-Na for 3-month waitlist mortality and showed the highest predictive value when combined (AUC: MELD-Na, 0.764; MELD-Na + CRP, 0.790; MELD-Na + vWF, 0.803; MELD-Na + CRP + vWF-Ag, 0.824). Results were confirmed in an independent validation cohort (n = 129; AUC: MELD-Na, 0.677; MELD-Na + CRP + vWF-Ag, 0.882). vWF-Ag was independently associated with PH and inflammatory biomarkers, whereas CRP closely, and MELD independently, correlated with biomarkers of bacterial translocation/inflammation.

CONCLUSIONS

The addition of vWF-Ag and CRP-reflecting central pathophysiological mechanisms of PH, bacterial translocation, and inflammation, that are all drivers of mortality on the waiting list for LT-to the MELD-Na score improves prediction of waitlist mortality. Using the vWFAg-CRP-MELD-Na model for prioritizing organ allocation may improve prediction of waitlist mortality and decrease waitlist mortality.

Coagulopathy, Bleeding Events, and Outcome According to Rotational Thromboelastometry in Patients With Acute Liver Injury/Failure

BACKGROUND AND AIMS

Patients with acute liver injury or failure (ALI/ALF) experience bleeding complications uncommonly despite an abnormal hemostatic profile. Rotational thromboelastometry (ROTEM), which assesses clot formation in whole blood, was used to determine the nature of abnormal hemostasis and whether it contributes to bleeding events, illness severity, or survival.

APPROACH AND RESULTS

A total of 200 patients were recruited from sites of the ALF Study Group. Blood collected daily for up to 5 days was analyzed using ROTEM delta devices. Consistent with standard laboratory evidence of hypocoagulability (median international normalized ratio = 2.9 and platelet count = 144 × 109 /L), patients frequently exhibited ROTEM parameters outside the normal range (73% and 62% had abnormalities in clot formation from extrinsic and intrinsic clotting cascades, respectively); however, measures of clot stability were generally normal. Eighteen patients (9%) experienced bleeding events, in whom clot initiation, assembly, and firmness were more severely deranged than patients without bleeding. Abnormal ROTEM parameters were more frequently observed in patients with non-acetaminophen ALI/ALF than those with acetaminophen ALI/ALF (clot initiation [P < 0.001], assembly [P = 0.02], firmness at 10 minutes [P = 0.05], and maximal firmness [P = 0.06]). Patients with more severe systemic complications (high-grade hepatic encephalopathy and need for renal replacement therapy) also had a higher incidence of abnormal ROTEM parameters. Finally, more hypocoagulable ROTEM parameters (clot initiation (P = 0.005), stiffness at 10 minutes (P = 0.05), and maximal stiffness by fibrin assembly (P = 0.004)) were observed in patients who died or underwent liver transplantation than those who survived with their native liver.

CONCLUSIONS

In patients with ALI/ALF, abnormal ROTEM parameters are frequent and proportional to disease severity. Whether the increased bleeding risk associated with abnormal ROTEM indicates hemostatic failure or is a proxy for disease severity requires additional study.

The utility of biomarkers in prognosis assessment of patients with acute liver failure

BACKGROUND

Acute liver failure (ALF) is a rare but potential lethal condition characterized by the sudden development of jaundice, coagulopathy and hepatic encephalopathy in patients without underlying liver disease. In selected patients, emergency liver transplantation is required. Selection of these patients is based on clinical criteria such as the Kings College Criteria (KCC) or the Clichy criteria.

AIMS

The aim of this work is to provide an overview of potential biomarkers that could improve the prognostic value of KCC.

RESULTS

Several promising biomarkers involved in related pathophysiological processes have been identified. Some could be as stand-alone biomarkers; however, the best prognostic values have been observed in the combination of biomarkers with current models. Among these, the ALFSG Index that combines clinical parameters and circulating blood levels of CK18 claims a higher prognostic value than KCC.

CONCLUSIONS

In this review, all potential biomarkers for ALF have been summarized to give an overview of the work performed over the last years, and a glimpse of what to expect in this field in the coming years.

Targeting von Willebrand factor in liver diseases: A novel therapeutic strategy?

Acute and chronic liver disease are associated with substantial alterations in the hemostatic system. Evidence from both experimental and clinical studies suggests that anticoagulants slow the progression of liver disease. Efficacy of those anticoagulant drugs is, in part, attributed to a reduction of microthrombi formation within the liver. Although anticoagulant drugs show promising results, bleeding risk associated with these drugs is an obvious drawback, particularly in patients with a complex coagulopathy driven by decreased liver function. Identifying therapies that reduce intrahepatic thrombosis with minimal bleeding risk would significantly advance the field. Among the hemostatic alterations observed in patients are substantially increased levels of the platelet-adhesive protein von Willebrand factor (VWF). In contrast, levels of A Disintegrin and Metalloproteinase with Thrombospondin motifs, the enzyme that regulates VWF activity, are significantly reduced in patients with liver disease. Highly elevated VWF levels are proposed to accelerate intrahepatic thrombus formation and thus be a driver of disease progression. Strong clinical evidence suggesting a link between liver disease and changes in VWF is now being matched by emerging mechanistic data showing a detrimental role for VWF in the progression of liver disease. This review focuses on clinical and experimental evidence supporting a connection between VWF function and the progression of acute and chronic liver diseases. Furthermore, with the recent anticipated approval of several novel therapies targeting VWF, we discuss potential strategies and benefits of targeting VWF as an innovative therapy for patients with liver disease.

VWF/ADAMTS13 Imbalance, But Not Global Coagulation or Fibrinolysis, Is Associated With Outcome and Bleeding in Acute Liver Failure

BACKGROUND AND AIMS

Recent studies of acute liver failure (ALF) in man and animals have suggested that rebalanced hemostasis occurs, with distinct hypercoagulable features clinically evidenced by a low risk of bleeding. Rodent models have shown a link between intrahepatic microthrombus formation and progression of ALF. We sought to confirm these earlier findings in a large series of patients with well-characterized ALF from the Acute Liver Failure Study Group.

APPROACH AND RESULTS

Citrated plasma samples taken on admission from 676 patients with ALF or acute liver injury (international normalized ratio ≥2.0 without hepatic encephalopathy) were used to determine levels of von Willebrand factor (VWF), a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) activity, thrombomodulin-modified thrombin generation, and clot lysis time (CLT) and compared with the levels in 40 healthy controls. Patients had 3-fold increased VWF levels, 4-fold decreased ADAMTS13 activity, similar thrombin generating capacity, and 2.4-fold increased CLT, compared with controls. Increasing disease severity was associated with progressively more elevated VWF levels as well as hypofibrinolysis. Patients who died or underwent liver transplantation within 21 days of admission had higher VWF levels, lower ADAMTS13 activity, but similar thrombin generation and a similar proportion of patients with severe hypofibrinolysis, when compared with transplant-free survivors. Likewise, patients with bleeding complications had higher VWF levels and lower ADAMTS13 activity compared to those without bleeding. Thrombin generation and CLT did not differ significantly between bleeding and nonbleeding patients.

CONCLUSIONS

Rebalanced hemostatic status was confirmed in a large cohort of patients with acute liver injury/ALF, demonstrating that VWF/ADAMTS13 imbalance is associated with poor outcome and bleeding. The association between VWF/ADAMTS13 imbalance and bleeding suggests that bleeding in ALF relates more to systemic inflammation than a primary coagulopathy.

The concept of rebalanced hemostasis in patients with liver disease: Communication from the ISTH SSC working group on hemostatic management of patients with liver disease

Patients with liver diseases acquire complex alterations in their hemostatic system that may lead to abnormalities in routine diagnostic test of hemostasis. Thrombocytopenia, prolongations in the prothrombin time and activated partial thromboplastin time, and decreased plasma fibrinogen are common in patients with advanced liver disease. Historically, liver diseases therefore have been classified as an acquired bleeding disorder. Laboratory and clinical observations have demonstrated that although routine diagnostic tests of hemostasis suggest a hypocoagulable state, patients with liver disease also tend to develop thrombotic events. Overall, patients have commensurate changes in both pro- and antihemostatic pathways. This new hemostatic balance, however, appears much more fragile than the hemostatic balance in individuals with normal liver function, and patients with liver disease can readily experience both hemostasis-related bleeding and thrombotic events. These insights into the hemostatic balance in patients with liver disease have led to revised recommendations for clinical management of hemostasis. In 2020, an SSC working group within the ISTH has been founded with the aim to disseminate new concepts on prevention and treatment of bleeding and thrombosis in patients with liver disease. The current document will outline the hemostatic changes in patients with liver disease, the limitations of routine diagnostic tests of hemostasis, and the concept of rebalanced hemostasis.

Predictive Ability of Preoperative PT-INR and Postoperative MCP1 for Post-hepatectomy Liver Failure

BACKGROUND

We sought a diagnostic tool using perioperative variables that might predict post-hepatectomy liver failure (PHLF).

PATIENTS AND METHODS

In 68 patients undergoing major hepatectomy, data on inflammatory markers and coagulation factors were prospectively collected and were compared between patients with International Study Group of Liver Surgery definition grade B/C PHLF (LF group) and those without LF (non-LF group).

RESULTS

Preoperatively, the LF group (n=9; 13.2%) had a lower platelet count and a disintegrin-like and metalloproteinase with thrombospondin type 1 motifs 13 (ADAMTS13) activity and a higher prothrombin time-International Normalized Ratio (PT-INR) than the non-LF group. On postoperative day 1, the LF group had significantly higher serum interleukin 6 (IL6), C-C motif chemokine ligand 2 (CCL2), and IL10 levels than the non-LF group. The logistic regression model that included preoperative PT-INR and CCL2 on postoperative day 1 predicted grade B/C PHLF with 100% sensitivity and 89.8% specificity.

CONCLUSION

Our findings suggest that the combination of preoperative PT-INR and CCL2 on postoperative day 1 can predict PHLF earlier and precisely after major hepatectomy.

Clinical Considerations of Coagulopathy in Acute Liver Failure

Acute liver failure (ALF) is the rapid onset of severe liver dysfunction, defined by the presence of hepatic encephalopathy and impaired synthetic function (international normalized ratio of ≥1.5) in the absence of underlying liver disease. The elevated international normalized ratio value in ALF is often misinterpreted as an increased hemorrhagic tendency, which can lead to inappropriate, prophylactic transfusions of blood products. However, global assessments of coagulopathy via viscoelastic tests or thrombin generation assay suggest a reestablished hemostatic, or even hypercoagulable, status in patients with ALF. Although the current versions of global assays are not perfect, they can provide more nuanced insights into the hemostatic system in ALF than the conventional measures of coagulopathy.

Disseminated intravascular coagulation: new identity as endotheliopathy-associated vascular microthrombotic disease based on in vivo hemostasis and endothelial molecular pathogenesis

Disseminated intravascular coagulation (DIC) can be correctly redefined as disseminated intravascular microthrombosis based on "two-path unifying theory" of in vivo hemostasis. "DIC" is a form of vascular microthrombotic disease characterized by "microthrombi" composed of platelets and unusually large von Willebrand factor multimers (ULVWF). Microthrombotic disease includes not only "DIC", but also microthrombosis occurring in thrombotic thrombocytopenic purpura (TTP), TTP-like syndrome, and focal, multifocal and localized microthrombosis. Being a hemostatic disease, microthrombotic disease occurs as a result of lone activation of ULVWF path via partial in vivo hemostasis. In endothelial injury associated with critical illnesses such as sepsis, the vascular damage is limited to the endothelial cell and activates ULVWF path. In contrast, in intravascular traumatic injury, the local damage may extend from the endothelial cell to subendothelial tissue and sometimes beyond, and activates both ULVWF and tissue factor (TF) paths. When endotheliopathy triggers exocytosis of ULVWF and recruits platelets, ULVWF path is activated and promotes microthrombogenesis to produce microthrombi composed of microthrombi strings, but when localized vascular damage causes endothelial and subendothelial tissue damage, both ULVWF and TF paths are activated and promote macrothrombogenesis to produce macrothrombus made of complete "blood clots". Currently, "DIC" concept is ascribed to activated TF path leading to fibrin clots. Instead, it should be correctly redefined as microthrombosis caused by activation of ULVWF path, leading to endotheliopathy-associated microthrombosis. The correct term for acute "DIC" is disseminated microthrombosis-associated hepatic coagulopathy, and that for chronic "DIC" is disseminated microthrombosis without hepatic coagulopathy. TTP-like syndrome is hematologic phenotype of endotheliopathy-associated microthrombosis. This correct concept of "DIC" is identified from novel theory of "in vivo hemostasis", which now can solve every mystery associated with "DIC" and other associated thrombotic disorders. Thus, sepsis-associated coagulopathy is not "DIC", but is endotheliopathy-associated vascular microthrombotic disease.

Coagulation status of critically ill patients with and without liver disease assessed using a novel thrombin generation analyzer

The liver synthesizes the majority of pro- and anti-coagulant and fibrinolytic proteins, and during liver dysfunction synthesis of these proteins is reduced. The end point of conventional hemostatic tests, such as the prothrombin time (PT), occurs when only 5% of thrombin generation (TG) has taken place and is not sensitive to the effects of natural anti-coagulants. The aim of this study was to determine whether TG in the presence of thrombomodulin (TM) provides more useful information about coagulation potential, in comparison to the PT. Analysis was performed on ST Genesia, a novel TG analyzer from Diagnostica Stago. TG was measured using STG-Thromboscreen, a reagent containing an intermediate concentration of human tissue factor (TF) ± rabbit TM to account for anti-coagulant protein C (PC) activity. Platelet-poor plasma (PPP) samples were from the Intensive Care Study of Coagulopathy-2 (ISOC-2), which recruited patients admitted to critical care with a prolonged PT (3 seconds above the reference range). Despite a prolonged PT, 48.0% and 60.7% of patients in the liver and non-liver groups had TG parameters within the normal range. Addition of TM reduced TG by 34.5% and 41.8% in the liver and non-liver groups, respectively. Interestingly, fresh frozen plasma (FFP) transfusion had no impact on TG. Measurement of TG with addition of TM provides a more informative assessment of coagulation capacity and indicates that hemostasis is balanced in patients with liver disease during critical illness, despite conventional tests suggesting that bleeding risk is increased.

Severe HELLP syndrome masquerading as thrombocytopenic thrombotic purpura: a case report

Background

Thrombotic microangiopathies (TMAs) occurring in the postpartum period may be difficult to manage. They present as the combination of mechanical hemolytic anemia and consumption thrombocytopenia due to endothelial dysfunction. The cause of this endothelial aggression can be multiple: thrombocytopenic thrombotic purpura (TTP), HELLP syndrome, antiphospholipid syndrome, atypical hemolytic and uremic syndrome or acute fatty liver of pregnancy. TTP results from a severe deficiency of ADAMTS13, which is a protease cleaving specifically von Willebrand factor chiefly produced by liver cells. There are two main causes, the production of anti-ADAMTS13 auto-antibodies and, more rarely, a genetic deficiency in ADAMTS13. First-line treatment is based on plasma exchange. HELLP syndrome occurs in the third trimester of pregnancy usually in association with preeclampsia and represents a form of TMA characterized by damage to the sinusoidal capillaries of the liver. Prompt delivery is the main treatment. We present a case illustrating the challenges in discriminating between different postpartum TMAs, with a focus on the distinction between TTP and HELLP syndrome. Specifically, we highlight how acute liver failure (ALF) stemming from HELLP may lead to TTP with a spectacular response to plasma exchanges.

Case

A 28-year-old, 33 + 4 weeks pregnant woman presented with severe preeclampsia complicated by ALF in the setting of partial liver necrosis, disseminated intravascular coagulation, microangiopathic hemolytic anemia and acute kidney injury. Greatly diminished levels of ADAMTS13 (< 5%) activity and neurological impairment suggested an initial diagnosis of thrombotic thrombocytopenic purpura (TTP). Therapeutic plasma exchange (TPE) was initiated and complete renal, neurological, hematological and hepatic recovery was observed. Secondary TTP induced by ALF due to HELLP syndrome was the final diagnosis.

Conclusion

Our case addresses the overlapping nature of postpartum TMAs and raises the possibility that HELLP-induced ALF may constitute an additional mechanism resulting in TTP, thereby opening a possible indication for TPE.

Traumatic injury results in prolonged circulation of ultralarge von Willebrand factor and a reduction in ADAMTS13 activity

BACKGROUND

Increases in plasma von Willebrand Factor (VWF) levels, accompanied by decreases in the metalloprotease ADAMTS13, have been demonstrated soon after traumatic injury while downstream effects remain unclear.

STUDY DESIGN AND METHODS

A cohort of 37 injured trauma patients from a randomized control trial investigating the use of prehospital plasma transfusion were analyzed for activity and antigen levels of ADAMTS13 and VWF at 0 and 24 hours after admission. Relevant clinical data were abstracted from the medical records. Trauma patient plasma was analyzed via agarose gel electrophoresis to evaluate the effects of injury on VWF multimer composition compared to healthy controls.

RESULTS

von Willebrand factor levels were elevated at presentation (189% [110%-263%] vs. 95% [74%-120%]), persisting through 24 hours (213% [146%-257%] vs. 132% [57%-160%]), compared to healthy controls. Ultralarge VWF (UL-VWF) forms were elevated in trauma patients at both 0 and 24 hours, when compared to pooled normal plasma (10.0% [8.9%-14.3%] and 11.3% [9.1%-21.2%], respectively, vs. 0.6%). Circulating plasma ADAMTS13 activity was decreased at 0 hours (66% [47%-86%] vs. 100% [98%-100%]) and at 24 hours (72.5% [56%-87.3%] vs. 103% [103%-103%]) in trauma patients. ADAMTS13 activity independently predicted the development of coagulopathy and correlated with international normalized ratio, thromboelastography values, injury severity, and blood product transfusion.

CONCLUSION

Traumatic injury is associated with acute coagulopathy that is characterized by increased UL-VWF multimers and reduction in ADAMTS13, which correlates with blood loss, transfusion requirement, and injury severity. These findings suggest the potential for future trials targeting ADAMTS13 repletion to enhance clearance of VWF multimers.

Coagulation abnormalities, bleeding, thrombosis, and management of patients with acute liver failure in Australia and New Zealand

BACKGROUND AND AIM

To study the management of coagulation and hematological derangements among severe acute liver failure (ALF) patients in Australia and New Zealand liver transplant intensive care units (ICUs).

METHODS

Analysis of key baseline characteristics, etiology, coagulation and hematological tests, use of blood products, thrombotic complications, and clinical outcomes during the first ICU week.

RESULTS

We studied 62 ALF patients. The first day median peak international normalized ratio was 5.5 (inter-quartile range [IQR] 3.8-8.7), median longest activated partial thromboplastin time was 62 s (IQR 44-87), and median lowest fibrinogen was 1.1 (IQR 0.8-1.6) g/L. Fibrinogen was only measured in 85% of patients, which was less than other tests (P < 0.0001). Median initial lowest platelet count was 83 (IQR 41-122) × 10⁹ /L. Overall, 58% of patients received fresh frozen plasma, 40% cryoprecipitate, 35% platelets, and 15% prothrombin complex concentrate. Patients with bleeding complications (19%) had more severe overall hypofibrinogenemia and thrombocytopenia. Thrombotic complications were less common (10% of patients), were not associated with consistent patterns of abnormal hemostasis, and were not immediately preceded by clotting factor administration and half occurred only after liver transplantation surgery.

CONCLUSION

In ALF patients admitted to dedicated Australia and New Zealand ICUs, fibrinogen was measured less frequently than other coagulation parameters but, together with platelets, appeared more relevant to bleeding risk. Blood products and procoagulant factors were administered to most patients at variable levels of hemostatic derangement, and bleeding complications were more common than thrombotic complications. This epidemiologic information and practice variability provide baseline data for the design and powering of interventional studies.