von Willebrand factor as a biomarker of clinically significant portal hypertension and severe portal hypertension: a systematic review and meta-analysis

Reappraisal of the conventional hemostasis tests as predictors of perioperative bleeding in the era of rebalanced hemostasis in cirrhosis

New global laboratory procedures mimicking the in vivo hemostasis process led to the changing paradigm of cirrhosis from the prototype of hemorrhagic diseases to a condition in which hemostasis is normal but fragile, thus justifying the hemorrhagic/thrombotic tendencies that affect these patients. The new paradigm was instrumental to change the management of cirrhosis. For example, international guidelines warn against the entrenched practice of testing patients with conventional hemostasis tests and infusing those with abnormalities with fresh-frozen plasma, coagulation factor concentrates, or platelets, prior to surgery/invasive procedures. These recommendations are, however, largely disattended. The practice of testing patients with the prothrombin time or viscoelastometry and using arbitrary cutoffs to make decisions on perioperative prophylaxis is still common and probably driven by medicolegal issues. There is no doubt that prothrombin time and congeners tests are unable to predict bleeding in cirrhosis. However, it cannot be excluded that some tests may be useful in patients who are severely decompensated. Large prospective collaborative studies are warranted. Enrolled patients should be randomized to receive perioperative prophylaxis based on laboratory testing (eg, viscoelastometry, thrombomodulin-modified thrombin generation) or to usual care. However, for these trials to be useful, a third group of patients who do not receive prophylaxis should be included. In conclusion, until results from these studies are available, physicians attending cirrhosis should refrain from using laboratory tests with arbitrary cutoffs to make decision on perioperative prophylaxis. Decision should be made by considering the clinical history of individual patients and the risk of hemorrhage of specific procedures.

Von Willebrand factor processing in patients with advanced chronic liver disease and its relation to portal hypertension and clinical outcome

BACKGROUND AND AIMS

Endothelial dysfunction and portal hypertension (PH) are reflected by increased von Willebrand factor antigen (VWF-Ag) levels in advanced chronic liver disease (ACLD). This study investigated VWF release and cleavage and their association with PH and clinical outcomes.

METHODS

Levels of VWF-Ag, VWF-N (VWF-propeptide), and VWF-A (VWF processed by the main VWF-cleaving protease ADAMTS13) were assessed in 229 patients with clinically stable ACLD (hepatic venous pressure gradient [HVPG] ≥ 6 mmHg; absence of bacterial infections or acute decompensation) undergoing HVPG-measurement. Liver-healthy individuals served as controls (n = 24).

RESULTS

VWF-Ag and VWF-N were similarly accurate for the identification of clinically significant PH (CSPH; HVPG ≥ 10 mmHg) in compensated ACLD (AUROC: VWF-Ag 0.748; VWF-N 0.728). ADAMTS13 activity was similar between patients with ACLD and controls and did not correlate with PH and disease severity, whereas VWF cleavage decreased in patients with CSPH (i.e., VWF-Ag/-A-ratio increased). In vitro VWF activity strongly reflected VWF-Ag levels (Spearman's r = 0.874, p < 0.001), but decreased (vs. controls) in patients with CSPH when normalized to VWF-Ag levels (VWF-activity/-Ag-ratio). VWF-Act/-Ag ratio correlated negatively with ADAMTS13 activity (r =- 0.256, p < 0.001). ADAMTS13 activity was independently predictive for (i) portal vein thrombosis (PVT) and (ii) hepatic decompensation or liver-related death.

CONCLUSIONS

VWF-Ag levels and its propeptide are similarly suitable surrogates of PH in patients with compensated ACLD. ADAMTS13-Act was not linked to disease and PH severity, however, when normalized to VWF-Ag, both VWF cleavage and VWF activity were decreased in patients with CSPH, as compared to liver-healthy individuals. Low ADAMTS13-Act was associated with presumably more procoagulant VWF and adverse outcomes.

CLINICAL TRIAL NUMBER

NCT03267615.

Transient elastography and von Willebrand factor as predictors of portal hypertension and decompensation in children

Background & Aims

Von Willebrand factor antigen (vWFAg), a protein measured to test the level of vWF released from the vascular endothelium has gained much attention as a marker for portal hypertension (PHT) severity. The objectives of this study were to investigate the use of vWFAg as a biomarker along with liver and spleen stiffness measurements by transient elastography as potential predictors of clinically significant varices (CSV), variceal bleeding (VB) and decompensation in children with PHT.

Methods

This observational prospective cohort study included 117 children (median age 10 [IQR 6-14] years) who underwent oesophagogastroduodenoscopy between January'2012 to November'2021 and a validation group of 33 children who underwent the same procedure between December'2021 to March'2023. Measurements of vWFAg and glycoprotein Ib binding activity of VWF (GPIbR) were available in 97 patients in the study group and in all patients in the validation group.Results: vWFAg and GPIbR were significantly higher in children with CSV (223 IU/dl and 166 IU/dl; p = 0.015 and p = 0.04, respectively) and VB (218 IU/dl and 174 IU/dl; p = 0.077 and p = 0.03, respectively) than in those without CSV or VB, respectively. Ninety-six patients had liver and spleen stiffness measurements. Spleen stiffness was significantly higher in patients with CSV compared to those without CSV (p = 0.003). In a chronic liver disease subgroup, a predictive scoring tool based on vWFAg, GPIbR, platelet count, and spleen/liver stiffness measurements could predict CSV with an AUROC of 0.76 (p = 0.04).

Conclusions

This study suggests the predictive value of vWF for CSV and VB increases when combined with spleen stiffness, with AUROCs of 0.88 and 0.82, respectively. Hence, a combination of biomarkers could assist clinicians in diagnosing CSV, preventing unnecessary invasive procedures.

Impacts and implications

Surveillance endoscopies in children with portal hypertension (PHT) have their own risks and non-invasive markers, such as von Willebrand factor antigen, glycoprotein Ib binding activity of VWF (GPIbR), and transient elastography could be used to predict clinically significant varices, variceal bleeding and disease compensation in children with PHT. Such non-invasive markers for PHT and varices are lacking in the paediatric population. The results show that von Willebrand factor and GPIbR along with transient elastography can be used to formulate a scoring system which can be used as a clinical tool by paediatric hepatologists to monitor the progression of PHT and risk of bleeding, and hence to stratify the performance of invasive endoscopic procedures under general anaesthesia. However, there is a need to validate the scoring system in children with portal vein thrombosis and for hepatic decompensation in a multi-centre registry in the future.

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.

Effect of far-infrared radiation therapy on von Willebrand factor in patients with chronic kidney disease

Background

Hemostatic abnormality has contributed to vascular access thrombosis in patients with chronic kidney disease (CKD). Previous studies have demonstrated that far-infrared radiation (FIR) therapy can maintain the patency and maturity of arteriovenous fistulas of patients undergoing hemodialysis (HD). However, prolonged access bleeding is observed once FIR is conducted at the end of dialysis. FIR can block the binding of platelet and von Willebrand factor (vWF), a predictor of hemostatic abnormality and vascular access thrombosis. However, clinical studies exploring FIR and vWF are sparse.

Methods

We recruited 20 HD patients, 21 CKD patients, and 20 controls to examine the alteration of vWF and a disintegrin and metalloproteinase with thrombospondin type 1 repeats 13 (ADAMTS13) following a single 40-min session of FIR therapy. In addition, the alteration of these factors in the HD group was examined following a 40-min FIR session thrice a week for 3 months.

Results

A decreasing trend in the vWF activity-antigen ratio of participants in all groups following a single FIR session was observed. In addition, the ratio in the HD group was significantly lower following 3 months of FIR therapy. The subgroup analysis revealed a consistent trend and multiple regression analysis showed that participants not taking hydroxymethylglutaryl-coenzyme A reductase inhibitor, diabetes mellitus, and higher hemoglobin levels were the significant factors. The alteration of the vWF activity-antigen ratio correlated moderately to that of ADAMTS13 antigen and activity.

Conclusion

FIR may alter the ratio of ultra-large vWF multimers through ADAMTS13, contributing to inhibiting platelet-endothelium interactions of CKD patients.

Microvascular Thrombosis and Liver Fibrosis Progression: Mechanisms and Clinical Applications

Fibrosis is an unavoidable consequence of chronic inflammation. Extracellular matrix deposition by fibroblasts, stimulated by multiple pathways, is the first step in the onset of chronic liver disease, and its propagation promotes liver dysfunction. At the same time, chronic liver disease is characterized by alterations in primary and secondary hemostasis but unlike previously thought, these changes are not associated with an increased risk of bleeding complications. In recent years, the role of coagulation imbalance has been postulated as one of the main mechanisms promoting hepatic fibrogenesis. In this review, we aim to investigate the function of microvascular thrombosis in the progression of liver disease and highlight the molecular and cellular networks linking hemostasis to fibrosis in this context. We analyze the predictive and prognostic role of coagulation products as biomarkers of liver decompensation (ascites, variceal hemorrhage, and hepatic encephalopathy) and liver-related mortality. Finally, we evaluate the current evidence on the application of antiplatelet and anticoagulant therapies for prophylaxis of hepatic decompensation or prevention of the progression of liver fibrosis.

Bibliometric-analysis visualization and review of non-invasive methods for monitoring and managing the portal hypertension

Background

Portal hypertension monitoring is important throughout the natural course of cirrhosis. Hepatic venous pressure gradient (HVPG), regarded as the golden standard, is limited by invasiveness and technical difficulties. Portal hypertension is increasingly being assessed non-invasively, and hematological indices, imaging data, and statistical or computational models are studied to surrogate HVPG. This paper discusses the existing non-invasive methods based on measurement principles and reviews the methodological developments in the last 20 years.

Methods

First, we used VOSviewer to learn the architecture of this field. The publications about the non-invasive assessment of portal hypertension were retrieved from the Web of Science Core Collection (WoSCC). VOSviewer 1.6.17.0 was used to analyze and visualize these publications, including the annual trend, the study hotspots, the significant articles, authors, journals, and organizations in this field. Next, according to the cluster analysis result of the keywords, we further retrieved and classified the related studies to discuss.

Results

A total of 1,088 articles or review articles about our topic were retrieved from WoSCC. From 2000 to 2022, the number of publications is generally growing. “World Journal of Gastroenterology” published the most articles (n = 43), while “Journal of Hepatology” had the highest citations. “Liver fibrosis” published in 2005 was the most influential manuscript. Among the 20,558 cited references of 1,088 retrieved manuscripts, the most cited was a study on liver stiffness measurement from 2007. The highest-yielding country was the United States, followed by China and Italy. “Berzigotti, Annalisa” was the most prolific author and had the most cooperation partners. Four study directions emerged from the keyword clustering: (1) the evaluation based on fibrosis; (2) the evaluation based on hemodynamic factors; (3) the evaluation through elastography; and (4) the evaluation of variceal bleeding.

Conclusion

The non-invasive assessment of portal hypertension is mainly based on two principles: fibrosis and hemodynamics. Liver fibrosis is the major initiator of cirrhotic PH, while hemodynamic factors reflect secondary alteration of splanchnic blood flow. Blood tests, US (including DUS and CEUS), CT, and magnetic resonance imaging (MRI) support the non-invasive assessment of PH by providing both hemodynamic and fibrotic information. Elastography, mainly USE, is the most important method of PH monitoring.

Ioxynil and diethylstilbestrol increase the risks of cardiovascular and thyroid dysfunction in zebrafish

Endocrine disruption results from exposure to chemicals that alter the function of the endocrine system in animals. Chronic 60 days of exposure to a low dose (0.1 μM) of ioxynil (IOX) or diethylstilbestrol (DES) via food was used to determine the effects of these chemicals on the physiology of the heart and thyroid follicles in juvenile zebrafish. Immunofluorescence analysis and subsequent 3D morphometric analysis of the zebrafish heart revealed that chronic exposure to IOX induced ventricle deformation and significant volume increase (p < 0.001). DES exposure caused a change in ventricle morphology, but volume was unaffected. Alongside, it was found that DES exposure upregulated endothelial related genes (angptl1b, mhc1lia, mybpc2a, ptgir, notch1b and vwf) involved in vascular homeostasis. Both IOX and DES exposure caused a change in thyroid follicle morphology. Notably, in IOX exposed juveniles, thyroid follicle hypertrophy was observed; and in DES-exposed fish, an enlarged thyroid field was present. In summary, chronic exposure of juvenile zebrafish to IOX and DES affected the heart and the thyroid. Given that both chemicals are able to change the morphology of the thyroid it indicates that they behave as endocrine disruptive chemicals (EDCs). Heart function dynamically changes thyroid morphology, and function and hence it is likely that the observed cardiac effects of IOX and DES are the source of altered thyroid status in these fish.

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.

Splenectomy ameliorates portal pressure and anemia in animal models of cirrhotic and non-cirrhotic portal hypertension

PURPOSE

Portal hypertension (PH)-associated splenomegaly is caused by portal venous congestion and splanchnic hyperemia. This can trigger hypersplenism, which favors the development of cytopenia. We investigated the time-dependent impact of splenectomy on portal pressure and blood cell counts in animal models of non-cirrhotic and cirrhotic PH.

MATERIALS AND METHODS

Ninety-six rats underwent either partial portal vein ligation (PPVL), bile duct ligation (BDL), or sham operation (SO), with subgroups undergoing additional splenectomy. Portal pressure, mean arterial pressure, heart rate, blood cell counts and hemoglobin concentrations were evaluated throughout 5 weeks following surgery.

RESULTS

Following PPVL or BDL surgery, the animals presented a progressive rise in portal pressure, paralleled by decreased mean arterial pressure and accelerated heart rate. Splenectomy curbed the development of PH in both models (PPVL: 16.25 vs. 17.93 ​mmHg, p ​= ​0.083; BDL: 13.55 vs. 15.23 ​mmHg, p ​= ​0.028), increased mean arterial pressure (PPVL: +7%; BDL: +9%), and reduced heart rate (PPVL: -10%; BDL: -13%). Accordingly, splenectomized rats had lower von Willebrand factor plasma levels (PPVL: -22%; BDL: -25%). Splenectomy resulted in higher hemoglobin levels in PPVL (14.15 vs. 13.08 ​g/dL, p ​< ​0.001) and BDL (13.20 vs. 12.39 ​g/dL, p ​= ​0.097) animals, and significantly increased mean corpuscular hemoglobin concentrations (PPVL: +9%; BDL: +15%). Thrombocytopenia only developed in the PPVL model and was alleviated in the splenectomized subgroup. Conversely, BDL rats presented with thrombocytosis, which was not affected by splenectomy.

CONCLUSIONS

Splenectomy improves both cirrhotic and non-cirrhotic PH, and ameliorates the hyperdynamic circulation. Hypersplenism related anemia and thrombocytopenia were only significantly improved in the non-cirrhotic PH model.

Von Willebrand Factor, Factor VIII, and Other Acute Phase Reactants as Biomarkers of Inflammation and Endothelial Dysfunction in Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGvHD) is an immune mediated late complication of allogeneic hematopoietic stem cell transplantation (alloHSCT). Discovery of adequate biomarkers could identify high-risk patients and provide an effective pre-emptive intervention or early modification of therapeutic strategy, thus reducing prevalence and severity of the disease among long-term survivors of alloHSCT. Inflammation, endothelial injury, and endothelial dysfunction are involved in cGvHD development. Altered levels of acute phase reactants have shown a strong correlation with the activity of several immune mediated disorders and are routinely used in clinical practice. Since elevated von Willebrand factor (VWF) and factor VIII (FVIII) levels have been described as acute phase reactants that may indicate endothelial dysfunction and inflammation in different settings, including chronic autoimmune diseases, they could serve as potential candidate biomarkers of cGvHD. In this review we focused on reported data regarding VWF and FVIII as well as other markers of inflammation and endothelial dysfunction, evaluating their potential role in cGvHD.