Von Willebrand disease-associated angiodysplasia: a few answers, still many questions

von Willebrand factor Ristocetin co-factor activity to von Willebrand factor antigen level ratio for diagnosis of acquired von Willebrand syndrome caused by aortic stenosis

Background

Severe aortic stenosis (AS) causes acquired von Willebrand syndrome by the excessive shear stress-dependent cleavage of high molecular weight multimers of von Willebrand factor (VWF). While the current standard diagnostic method is so-called VWF multimer analysis that is western blotting under nonreducing conditions, it remains unclear whether a ratio of VWF Ristocetin co-factor activity (VWF:RCo) to VWF antigen levels (VWF:Ag) of <0.7, which can be measured with an automated coagulation analyzer in clinical laboratories and is used for the diagnosis of hereditary von Willebrand disease.

Objectives

To evaluated whether the VWF:RCo/VWF:Ag is useful for the diagnosis of AS-induced acquired von Willebrand syndrome.

Methods

VWF:RCo and VWF:Ag were evaluated with the VWF large multimer index as a reference, which represents the percentage of a patient's VWF high molecular weight multimer ratio to that of standard plasma in the VWF multimer analysis.

Results

We analyzed 382 patients with AS having transaortic valve maximal pressure gradients of >30 mmHg, 27 patients with peripheral artery disease, and 46 control patients free of cardiovascular disease with osteoarthritis, diabetes, and so on. We assumed a large multimer index of <80% as loss of VWF large multimers since 59.0% of patients with severe AS had the indices of <80%, while no control patients or patients with peripheral artery disease, except for 2 patients, exhibited the indices of <80%. The VWF:RCo/VWF:Ag ratios, measured using an automated blood coagulation analyzer, were correlated with the indices (rs = 0.470, P < .001). When the ratio of <0.7 was used as a cut-off point, the sensitivity and specificity to VWF large multimer indices of <80% were 0.437 and 0.826, respectively.

Conclusion

VWF:RCo/VWF:Ag ratios of <0.7 may indicate loss of VWF large multimers with high specificity, but low sensitivity. VWF:RCo/VWF:Ag ratios in patients with AS having a ratio of <0.7 may be useful for monitoring the loss of VWF large multimers during their clinical courses.

Effectiveness of aortic valve replacement in Heyde syndrome: a meta-analysis

AIMS

Heyde syndrome is the co-occurrence of aortic stenosis, acquired von Willebrand syndrome, and gastrointestinal bleeding. Aortic valve replacement has been demonstrated to resolve all three associated disorders. A systematic review and meta-analysis were performed to obtain best estimates of the effect of aortic valve replacement on acquired von Willebrand syndrome and gastrointestinal bleeding.

METHODS AND RESULTS

A literature search was performed to identify articles on Heyde syndrome and aortic valve replacement up to 25 October 2022. Primary outcomes were the proportion of patients with recovery of acquired von Willebrand syndrome within 24 h (T1), 24-72 h (T2), 3-21 days (T3), and 4 weeks to 2 years (T4) after aortic valve replacement and the proportion of patients with cessation of gastrointestinal bleeding. Pooled proportions and risk ratios were calculated using random-effects models. Thirty-three studies (32 observational studies and one randomized controlled trial) on acquired von Willebrand syndrome (n = 1054), and 11 observational studies on gastrointestinal bleeding (n = 300) were identified. One study reported on both associated disorders (n = 6). The pooled proportion of Heyde patients with acquired von Willebrand syndrome recovery was 86% (95% CI, 79%-91%) at T1, 90% (74%-96%) at T2, 92% (84%-96%) at T3, and 87% (67%-96%) at T4. The pooled proportion of Heyde patients with gastrointestinal bleeding cessation was 73% (62%-81%). Residual aortic valve disease was associated with lower recovery rates of acquired von Willebrand syndrome (RR 0.20; 0.05-0.72; P = 0.014) and gastrointestinal bleeding (RR 0.57; 0.40-0.81; P = 0.002).

CONCLUSION

Aortic valve replacement is associated with rapid recovery of the bleeding diathesis in Heyde syndrome and gastrointestinal bleeding cessation. Residual valve disease compromises clinical benefits.

Targeting von Willebrand disease: the current status and future directions of management therapies

INTRODUCTION

von Willebrand disease (VWD) is the commonest inherited bleeding disorder, and is typically caused by deficits in the quantity or quality of von Willebrand factor (VWF).

AREAS COVERED

This review describes the main clinical, diagnostic, and therapeutic aspects of VWD, with particular attention to its management. In addition, standard and avant-garde replacement therapies based on the use of VWF are discussed.

EXPERT OPINION

The goal of treatment for VWD is to reverse the double hemostatic defect resulting from the abnormal or reduced expression of VWF and the concomitant factor VIII (FVIII) deficiency. Treatment consists of managing any bleeds and both short-term prophylaxis (i.e. for surgery or invasive procedures) and long-term prophylaxis. While desmopressin is suitable for most patients with type 1 VWD, VWF/FVIII concentrates are the treatment of choice for the other types of VWD. Beside plasma-derived VWF/FVIII concentrates, whose safety and efficacy have been demonstrated by several clinical trials, products containing only VWF, obtained by plasma fractionation and recombinant DNA technology, have become available and marketed more recently. The clinical use of these VWF-only products is particularly attractive in the setting of surgery and long-term prophylaxis, such as the prevention of recurrent gastrointestinal bleeding in cases of angiodysplasia.

Gastrointestinal bleeding in von Willebrand patients: special diagnostic and management considerations

INTRODUCTION

Severe and recurrent gastrointestinal (GI) bleeding caused by angiodysplasia is a significant problem in patients with von Willebrand disease (VWD) and in those with acquired von Willebrand syndrome (AVWS). At present, angiodysplasia-related GI bleeding is often refractory to standard treatment including replacement therapy with von Willebrand factor (VWF) concentrates and continues to remain a major challenge and cause of significant morbidity in patients despite advances in diagnostics and therapeutics.

AREAS COVERED

This paper reviews the available literature on GI bleeding in VWD patients, examines the molecular mechanisms implicated in angiodysplasia-related GI bleeding, and summarizes existing strategies in the management of bleeding GI angiodysplasia in patients with VWF abnormalities. Suggestions are made for further research directions.

EXPERT OPINION

Bleeding from angiodysplasia poses a significant challenge for individuals with abnormal VWF. Diagnosis remains a challenge and may require multiple radiologic and endoscopic investigations. Additionally, there is a need for enhanced understanding at a molecular level to identify effective therapies. Future studies of VWF replacement therapies using newer formulations as well as other adjunctive treatments to prevent and treat bleeding will hopefully improve care.

Real-world healthcare costs and resource utilization in patients with von Willebrand disease and angiodysplasia

OBJECTIVE

To describe the economic burden among VWD patients with angiodysplasia compared to VWD patients without angiodysplasia and the general population.

METHODS

This was a retrospective analysis using the Merative MarketScan Commercial and Medicare Databases® (January 2011-September 2020). Selected patients had ≥1 medical claim for VWD or low VWF, ≥1 medical claim for AGD, and ≥3 GI-related bleeding episodes within a year. HCRU and all-cause costs were compared with the VWD (only) and the general cohorts.

RESULTS

The mean total all-cause costs were $150,101 among patients with VWD and angiodysplasia (n = 34), higher compared to $48,249 among matched VWD patients without angiodysplasia (n = 136) and $31,029 among matched individuals of the general population [n = 136; p-value < 0.0001]. The differences in costs between groups were primarily due to inpatient care. During the 12-month follow-up, VWD patients with symptomatic (n = 35), asymptomatic (n = 81), and suspected (n = 378) angiodysplasia had an average of 4.1, 0.6, and 3.8 gastrointestinal (GI) bleeds, respectively. Desmopressin, VWF concentrates, and aminocaproic acid were the most frequent treatments used. The most frequent procedures to treat GI-related bleeding and underlying lesions were blood transfusion and laser therapy.

CONCLUSIONS

Despite recent therapeutic advances, there is room for considerable reduction of the disease burden in patients with VWD and angiodysplasia.

von Willebrand factor neutralizing and non-neutralizing alloantibodies in 213 subjects with type 3 von Willebrand disease enrolled in 3WINTERS-IPS

BACKGROUND

Type 3 von Willebrand disease (VWD) is the most severe form of this disease owing to the almost complete deficiency of von Willebrand factor (VWF). Replacement therapy with plasma-derived products containing VWF or recombinant VWF rarely cause the development of alloantibodies against VWF that may be accompanied by anaphylactic reactions.

OBJECTIVE

The objective of this study was to assess the prevalence of anti-VWF alloantibodies in subjects with type 3 VWD enrolled in the 3WINTERS-IPS.

METHODS

An indirect in-house enzyme-linked immunosorbent assay has been used to test all the alloantibodies against VWF. Neutralizing antibodies (inhibitors) have been tested with a Bethesda-based method by using a VWF collagen binding (VWF:CB) assay. Samples positive for anti-VWF antibodies were further tested with Bethesda-based methods by using the semiautomated gain-of-function glycoprotein-Ib binding (VWF:GPIbM) and a VWF antigen (VWF:Ag) enzyme-linked immunosorbent assay.

RESULTS

In total, 18 of the 213 (8.4%) subjects tested positive for anti-VWF antibodies and 13 of 213 (6%) had VWF:CB inhibitors. These 13 were among the 18 with anti-VWF antibodies. Of the 5 without VWF:CB inhibitors, 3 had non-neutralizing antibodies, 1 only inhibitor against VWF:GPIbM, and one could not be tested further. Ten of the 13 subjects with VWF:CB inhibitors also had VWF:GPIbM inhibitors, 6 of whom also had VWF:Ag inhibitors. Subjects with inhibitors were homozygous for VWF null alleles (11/14), homozygous for a missense variant (1/14), or partially characterized (2/14).

CONCLUSIONS

Anti-VWF antibodies were found in 8.4% of subjects with type 3 VWD, whereas neutralizing VWF inhibitors were found in 6%, mainly in subjects homozygous for VWF null alleles. Because inhibitors may be directed toward different VWF epitopes, their detection is dependent on the assay used.

Jejunal Angiodysplasia in an Elderly Patient with Aortic Stenosis: Significance of Von Willebrand Factor as an Etiologic Factor

Heyde's syndrome is a disease in which patients with aortic stenosis (AS) bleed from angiodysplasia. An 80-year-old woman with a history of severe AS was referred to our hospital with melena and anemia. The patient underwent jejunal resection after repeated blood transfusions. A pathological examination revealed angiodysplasia, and the patient's plasma lacked high-molecular-weight von Willebrand factor (VWF) multimers, leading to the diagnosis of Heyde's syndrome. The patient underwent transcatheter aortic valve implantation (TAVI) one year after the diagnosis, and the VWF index recovered. This is a valuable case in which the pathological analysis of angiodysplasia associated with Heyde's syndrome was possible.

A Case of Heyde's Syndrome With Subvalvular Aortic Stenosis

Heyde's syndrome is a constellation of severe aortic stenosis, gastrointestinal arteriovenous malformations (AVMs), and an acquired von Willebrand type 2A coagulopathy resulting in moderate-to-severe gastrointestinal bleeding. Additional cardiac lesions have been observed to cause Heyde's syndrome including aortic regurgitation, mitral regurgitation, aortic/mitral valve prosthetic dysfunction, ventricular septal defects, hypertrophic cardiomyopathy, left ventricular assist devices, and extracorporeal life support devices. Repairing the cardiac lesion or removing the device decreases the incidence of gastrointestinal bleeding by normalizing the acquired von Willebrand coagulopathy and decreasing the amount of gastrointestinal AVMs likely to bleed. We describe a case of a 67-year-old woman found to have Heyde's syndrome arising from a subvalvular aortic membrane resulting in severe subaortic stenosis with no other significant cardiac lesion. She underwent successful resection of the membrane with septal myectomy, relieving the severe subaortic stenosis and resolving her anemia. Years later, she re-presented with severe gastrointestinal bleeding from gastrointestinal malformations. Early recognition of these cardiac lesions with gastrointestinal bleeds may help decrease the morbidity and mortality that Heyde's syndrome portends and provide evidence for early intervention.

Prophylactic management of patients with von Willebrand disease

Von Willebrand disease, the most common inherited bleeding disorder that affects both males and females, is due to quantitative or qualitative defects of the multimeric glycoprotein von Willebrand factor, which cause mucous membrane bleeding but also soft tissue bleeding owing to the secondary deficiency of factor VIII. The aim of treatment is to correct this dual defect of hemostasis. In addition to the episodic management of bleeding episodes, therapy includes their short- or long-term prevention. Short-term prophylaxis is mainly warranted in order to provide effective hemostatic coverage to patients undergoing surgery or invasive procedures and to affected women at the time of delivery or during menstruations associated with excessive bleeding. The aim of long-term prophylaxis is to prevent bleeding in particular categories of patients at increased risk of frequent and spontaneous bleeding in the joints, nose, and gastrointestinal tract.

A Comparative Study of Invasive Modalities for Evaluation of Pulmonary Arteriovenous Fistula after Bidirectional Glenn Shunt

Development of pulmonary AV fistula (PAVF) after bidirectional glenn shunt (BDG) results in significant cyanosis, impaired exercise performance, and increased morbidity and mortality. We attempted to detect and quantify PAVF in post-BDG patients by saline contrast transesophageal echocardiography (TEE) and compare with pulmonary angiography and pulmonary vein oximetry. This was a prospective study done between 2017 and 2018. Twenty-five children who underwent BDG and planned for cardiac catheterization prior to Fontan completion were included in the study. All patients underwent pulmonary angiography, oximetry, and saline contrast TEE at the time of cardiac catheterization. Twenty-two patients had undergone unilateral BDG surgery and three were palliated by bilateral BDG. The mean oxygen saturation was 80 ± 5.2%. Thirteen patients (52%) had preserved antegrade pulmonary blood flow. Eighteen patients (72%) had PAVF by angiography and oximetry, while 19 (76%) had PAVF identified by contrast echocardiography. There was moderate correlation between the degree of pulmonary venous desaturation and grading of PAVF by contrast echocardiography. PAVF was predominantly located in the lower zones of the lungs. Higher grades of PAVF were not seen in patients with preserved antegrade flow after BDG. Angiographically detected PAVF showed a steady increase with increasing delay to cardiac catheterization from BDG. Significant reduction in systemic saturation was limited to advanced grades of PAVF in patients after BDG. Saline contrast TEE, pulmonary venous oximetry, and pulmonary angiography equally identified PAVF in patients after BDG. Prognostic utility of the same needs to be assessed by long-term follow-up of these subjects.

Aortic stenosis and Heyde’s syndrome: A comprehensive review

Heyde’s syndrome is an under reported systemic disease of gastrointestinal and cardiac manifestation in older adults. It is characterized by a triad of aortic stenosis, angiodysplasia with bleeding and acquired von Willebrand syndrome. It is characterized by proteolysis of high molecular weight multimers of von Willebrand Factor and loss of platelet mediated homeostasis. Heyde’s syndrome is a treatable condition in most cases, especially in the current era of evolution in interventional cardiology and gastroenterology. There are currently no established guidelines in the management of this condition due to paucity of high quality studies, which warrant future trials. High index of suspicion and increasing the awareness of the syndrome among the general practitioners and sub-specialists will improve the diagnostic potential of Heyde’s syndrome. Future studies may change the management aspect of Heyde's syndrome and pave a path for drawing specific guidelines and algorithms. The aim of our review article is to summarize the basic pathophysiology, diagnostics and management of Heyde’s syndrome with a special attention to Transcatheter aortic valve replacement.

Gastrointestinal bleeding from angiodysplasia in von Willebrand disease: Improved diagnosis and outcome prediction using videocapsule on top of conventional endoscopy

BACKGROUND

Despite a high prevalence of angiodysplasia, no specific guidelines are available for the modalities of endoscopic exploration of gastrointestinal (GI) bleeding in von Willebrand disease (VWD). Whether VWD patients could benefit from video capsule endoscopy (VCE) looking for angiodysplasia eligible to endoscopic treatment or at high risk of bleeding is unknown.

OBJECTIVES

To assess the diagnostic efficacy for angiodysplasia and the prognostic value of VCE on top of conventional endoscopy in VWD patients with GI bleeding.

PATIENTS/METHODS

A survey was sent to the 30 centers of the French-network on inherited bleeding disorders to identify VWD patients referred for endoscopic exploration of GI bleeding from January 2015 to December 2017. Data obtained included patient characteristics, VWD phenotype/genotype, GI bleeding pattern, results of endoscopic investigations, and medical management applied including endoscopic therapy. We assessed by Kaplan-Meier analysis the recurrence-free survival after the first GI bleeding event according to endoscopic categorization and, in patients with angiodysplasia, to the presence of small-bowel localizations on VCE exploration.

RESULTS

GI bleeding source localization was significantly improved when including VCE exploration (P < .01), even in patients without history of angiodysplasia (P < .05). Patients with angiodysplasia had more GI bleeding recurrences (P < .01). A lower recurrence-free survival was observed in patients with angiodysplasia (log-rank test, P = .02), and especially when lesions were located in the small bowel (log-rank test, P < .01), even after endoscopic treatment with argon plasma coagulation (log-rank test, P < .01).

CONCLUSION

VCE should be more systematically used in VWD patients with unexplained or recurrent GI bleeding looking for angiodysplasia eligible to endoscopic treatment or at high risk of relapse.

Bleeding symptoms in patients diagnosed as type 3 von Willebrand disease: Results from 3WINTERS-IPS, an international and collaborative cross-sectional study

BACKGROUND

Type 3 von Willebrand's disease (VWD) patients present markedly reduced levels of von Willebrand factor and factor VIII. Because of its rarity, the bleeding phenotype of type 3 VWD is poorly described, as compared to type 1 VWD.

AIMS

To evaluate the frequency and the severity of bleeding symptoms across age and sex groups in type 3 patients and to compare these with those observed in type 1 VWD patients to investigate any possible clustering of bleeding symptoms within type 3 patients.

METHODS

We compared the bleeding phenotype and computed the bleeding score (BS) using the MCMDM-1VWD bleeding questionnaire in patients enrolled in the 3WINTERS-IPS and MCMDM-1VWD studies.

RESULTS

In 223 unrelated type 3 VWD patients, both the BS and the number of clinically relevant bleeding symptoms were increased in type 3 as compared to type 1 VWD patients (15 versus 6 and 5 versus 3). Intracranial bleeding, oral cavity, hemarthroses, and deep hematomas were at least five-fold over-represented in type 3 VWD. A more severe bleeding phenotype was evident in patients having von Willebrand factor antigen levels < 20 IU/dL at diagnosis in the two merged cohorts. In type 3 patients, there was an apparent clustering of hemarthrosis with gastrointestinal bleeding and epistaxis, whereas bleeding after surgery or tooth extraction clusters with oral bleeding and menorrhagia.

CONCLUSIONS

In the largest cohort of type 3 VWD patients, we were able to describe a distinct clinical phenotype that is associated with the presence of a more severe hemostatic defect.

A reappraisal of the pharmacologic management of gastrointestinal bleeding in patients with continuous flow left ventricular assist devices

Advancements in the design and functionality of continuous flow left ventricular assist devices (CF-LVADs), as well as a limited number of donor hearts, have resulted in an increased utilization of this therapy among advanced heart failure (HF) patients. Despite these advancements, gastrointestinal bleeding (GIB) remains a common complication after CF-LVAD implantation. The mechanism of GIB in these patients is complex and includes a combination of angiodysplasia, platelet dysfunction, acquired von Willebrand disease, and a variety of patient-specific factors including advanced age and history of GIB. Several pharmacotherapy options have been reported in the literature, though studies supporting the use of these agents are often small, retrospective reports. Within this review, we discuss the various pharmacologic agents, their proposed mechanisms of action, and the available literature pertaining to their effectiveness and tolerability. Additionally, we propose an evidence-based treatment algorithm, encompassing the updated literature, cost of therapy, medication side effects, and ease of administration.

Acquired von Willebrand Syndrome Hiding Inherited von Willebrand Disease Can Explain Severe Bleeding in Patients With Aortic Stenosis

OBJECTIVE

Aortic stenosis may be complicated by an acquired von Willebrand syndrome that rarely causes significant bleeding, raising the question of why it does so in a few cases. To seek an explanation, we studied 5 severe bleeder aortic stenosis patients in a cohort of 49 patients, using the flowchart for inherited von Willebrand disease. Approach and Results: All 5 patients were lacking in large and intermediate VWF (von Willebrand factor) multimers, 3 had reduced plasma and platelet VWF levels, and none showed PFA100 closure. Two patients (those with most multimers missing) also had a short VWF half-life. Genetic analyses on the 3 patients with reduced platelet VWF levels revealed that one carried both the c.1164C>G and the c.7880G>A mutations, and another carried the c.3390C>T mutation, while the third had one of the 2 VWF alleles relatively less expressed than the other (25% versus 75%). No genetic alterations emerged in the other 2 patients. Successful replacement of the stenotic aortic valve, performed in the 2 patients with VWF mutations, did not correct their abnormal VWF multimer picture-unlike what happened in the aortic stenosis patients without bleeding symptoms.

CONCLUSIONS

Our findings suggest that acquired von Willebrand syndrome can develop in patients with hitherto-undiagnosed inherited von Willebrand disease. Since von Willebrand disease is the most common bleeding disorder, this possibility should be considered in aortic stenosis patients-especially those with a more severe bleeding history and more disrupted VWF laboratory patterns-because they risk hemorrhage during aortic valve replacement.

Of aortic valve and bleeding: Heyde's syndrome

An 80-year-old woman with severe aortic stenosis presented with relapsing enterorrhagia and severe anemia. A video capsule pan-endoscopy showed multiple sites of complex mucosal angiodysplasia in the jejunum. Direct hemostatic treatment of accessible angiodysplasia was done with argon plasma coagulation, and the patient was urgently referred for trans-catheter aortic valve replacement (TAVR). At follow-up 1 month and 3 months later, she was doing well with no further episodes of bleeding. Heyde's syndrome is referred to as the association of aortic stenosis, gastrointestinal angiodysplasia, bleeding, and anemia. It is an acquired type2A von Willebrand syndrome caused by the proteolysis and loss of the largest polymers of vWF due to the high shear forces generated through the stenotic aortic valve. The qualitative and quantitative vWF defects play a central role in the angiogenesis and development of gastrointestinal angiodysplasia The vWF abnormalities are closely associated with the hemodynamic severity of the aortic valve stenosis. Valve replacement is the pivotal strategy to achieve the long-term resolution of bleeding recurrences. TAVR is a valuable option particularly in high-risk patients for whom surgical valve replacement is not feasible.

Coexistence of Von Willebrand disease and gastrointestinal stromal tumor (G.I.S.T): Case report of a rare and challenge association

Von Willebrand disease (VWD) is the most common inherited bleeding disorder and is caused by a quantitative (type 1 and 3) or qualitative (type 2) defect of Von Willebrand factor (VWF). Bleeding from the gastrointestinal (GI) tract is not uncommon in VWD and is usually associated with angiodysplasia. We report herein on the management of a patient affected by VWD2B with severe GI bleeding secondary to gastrointestinal stromal tumor (GIST) complicated by deep vein thrombosis (DVT). The current case demonstrated that the hemostatic balance, in RBDs under specific circumstances, can range from a tendency toward a hemorrhagic to normal or prothrombotic state. In these patients, a close collaboration between hematologists and surgeons can guarantee appropriate management in high-risk clinical scenarios.

Alternative trafficking of Weibel-Palade body proteins in CRISPR/Cas9-engineered von Willebrand factor-deficient blood outgrowth endothelial cells

BACKGROUND

Synthesis of the hemostatic protein von Willebrand factor (VWF) drives formation of endothelial storage organelles called Weibel-Palade bodies (WPBs). In the absence of VWF, angiogenic and inflammatory mediators that are costored in WPBs are subject to alternative trafficking routes. In patients with von Willebrand disease (VWD), partial or complete absence of VWF/WPBs may lead to additional bleeding complications, such as angiodysplasia. Studies addressing the role of VWF using VWD patient-derived blood outgrowth endothelial cells (BOECs) have reported conflicting results due to the intrinsic heterogeneity of patient-derived BOECs.

OBJECTIVE

To generate a VWF-deficient endothelial cell model using clustered regularly interspaced short palindromic repeats (CRISPR) genome engineering of blood outgrowth endothelial cells.

METHODS

We used CRISPR/CRISPR-associated protein 9 editing in single-donor cord blood-derived BOECs (cbBOECs) to generate clonal VWF -/- cbBOECs. Clones were selected using high-throughput screening, VWF mutations were validated by sequencing, and cells were phenotypically characterized.

RESULTS

Two VWF -/- BOEC clones were obtained and were entirely devoid of WPBs, while their overall cell morphology was unaltered. Several WPB proteins, including CD63, syntaxin-3 and the cargo proteins angiopoietin (Ang)-2, interleukin (IL)-6, and IL-8 showed alternative trafficking and secretion in the absence of VWF. Interestingly, Ang-2 was relocated to the cell periphery and colocalized with Tie-2.

CONCLUSIONS

CRISPR editing of VWF provides a robust method to create VWF- deficient BOECs that can be directly compared to their wild-type counterparts. Results obtained with our model system confirmed alternative trafficking of several WPB proteins in the absence of VWF and support the theory that increased Ang-2/Tie-2 interaction contributes to angiogenic abnormalities in VWD patients.

Characterization of a Porcine Model for Von Willebrand Disease Type 1 and 3 Regarding Expression of Angiogenic Mediators in the Nonpregnant Female Reproductive Tract

Von Willebrand disease (VWD), a blood coagulation disorder, is also known to cause angiodysplasia. Hitherto, no animal model has been found with angiodysplasia that can be studied in vivo. In addition, VWD patients tend to have a higher incidence of miscarriages for reasons unknown. Thus, we aimed to examine the influence of von Willebrand factor (VWF) on the female reproductive tract histology and the expression and distribution of angiogenic factors in a porcine model for VWD types 1 and 3. The disease-causing tandem duplication within the VWF gene occurred naturally in these pigs, making them a rare and valuable model. Reproductive organs of 6 animals (2 of each mutant genotype and 2 wildtype (WT) animals) were harvested. Genotype plus phenotype were confirmed. Several angiogenic factors were chosen for possible connections to VWF and analyzed alongside VWF by immunohistochemistry and quantitative gene expression studies. VWD type 3 animals showed angiodysplasia in the uterus and shifting of integrin α_Vβ₃ from the apical membrane of uterine epithelium to the cytoplasm accompanied by increased vascular endothelial growth factor (VEGF) expression. Varying staining patterns for angiopoietin (Ang)-2 were observed among the genotypes. As compared with WT, the ovaries of the VWD type 3 animals showed decreased gene expression of ANG2 and increased gene expression of TIE (tyrosine kinase with immunoglobulin and epidermal growth factor homology domains) 2, with some differences in the ANG/TIE-system among the mutant genotypes. In conclusion, severely reduced VWF seems to evoke angiodysplasia in the porcine uterus. Varying distribution and expression of angiogenic factors suggest that this large animal model is promising for investigation of influence of VWF on angiogenesis in larger groups.

Heyde Syndrome: Aortic Stenosis and Beyond

Heyde described aortic stenosis and gastrointestinal bleeding in the 1950s. Since then, a link with intestinal angiodysplasia and abnormalities of von Willebrand factor (VWF) has been noted. Loss of the highest-molecular-weight multimers of VWF and bleeding also have been described in subaortic stenosis in hypertrophic cardiomyopathy, in isolated mitral and aortic insufficiency, in endocarditis, in patients with prosthetic valve stenosis or regurgitation, and in patients with left ventricular assist devices (LVADs). Bleeding tends to recur with local treatment of angiodysplasias, whereas cardiac repair or removal of LVAD eliminates VWF dysfunction is curative of bleeding in the majority.

Blood inflammatory and endothelial markers in women with von Willebrand disease

Introduction

VWD-affected females often experience menorrhagia. Periodical fluctuations of the sex steroids during the menstrual cycle cause changes both in the coagulation and immune system. The aim of the current study was to assess the changes in selected inflammatory and endothelial markers in women with VWD during two phases of the menstrual cycle (follicular and luteal) and to compare it with corresponding data from healthy controls.

Materials and methods

The study group included 12 VWD-affected females with regular menstrual cycle, with none of them being prescribed hormone treatment. They were not pregnant or breastfeeding. The control group consisted of 102 healthy females, matched for age and BMI.

Results

Within the VWD group, endostatin was higher during the follicular phase, compared to the luteal phase, although the difference was not significant (p = 0.062). sICAM-1 and IL-6 were higher in VWD-affected females, compared to the controls, sVCAM-1, cathepsin S and sP-selectin were lower (p<0.003 for all cases). The pattern was constant throughout the menstrual cycle.

Conclusions

Higher levels of endostatin during early follicular phase could potentially predispose women with VWD to the development of heavy menstrual bleeding, due to antiangiogenic properties and ability to suppress several coagulation factors. Lower p-selectin levels in VWD group, compared to controls, may also contribute to the bleeding tendency. Changes in other proteins, involved in angiogenesis are hypothetically related to the formation of angiodysplasia—common complication of VWF deficiency. The latter statement requires confirmation in larger studies.

[Von Willebrand disease]

Von Willebrand factor is involved in primary hemostasis (adhesion of platelets to subendothelium and platelet aggregation) and acts as the carrier of coagulation factor VIII. Von Willebrand disease, resulting from a quantitative or qualitative defect of this factor, is the most frequent inherited bleeding disorder. It is mainly responsible for symptoms such as mucocutaneous bleeding and excessive bleeding after trauma or invasive procedures, but can also cause gastro-intestinal bleeding or hemarthrosis in the most severe forms of the disease. There are numerous causes of physiological variation of von Willebrand factor plasma levels which can be responsible for diagnostic difficulty or changes in symptoms over time. Diagnosis relies primarily on clinical symptoms but requires the use of several laboratory analyses: von Willebrand factor activity and antigen testing and factor VIII activity. More specialized assays allow classification of the disease in various types and subtypes which imply different management strategies (types 1, 2A, 2B, 2M, 2N, and 3). Treatment is based on desmopressin, responsible for an increase in plasma concentration of von Willebrand factor, and plasma-derived von Willebrand factor concentrates which can be combined with factor VIII.

A Case of Heyde Syndrome with Resolution of Gastrointestinal Bleeding Two Weeks After Aortic Valve Replacement

Patient: Female, 56

Final Diagnosis: Heyde syndrome

Symptoms: Anemia • gastrointesinal haemorrhage

Medication: —

Clinical Procedure: Colonoscopy • EGD • TAVR

Specialty: Gastroenterology and Hepatology

von Willebrand factor regulation of blood vessel formation

Several important physiological processes, from permeability to inflammation to hemostasis, take place at the vessel wall and are regulated by endothelial cells (ECs). Thus, proteins that have been identified as regulators of one process are increasingly found to be involved in other vascular functions. Such is the case for von Willebrand factor (VWF), a large glycoprotein best known for its critical role in hemostasis. In vitro and in vivo studies have shown that lack of VWF causes enhanced vascularization, both constitutively and following ischemia. This evidence is supported by studies on blood outgrowth EC (BOEC) from patients with lack of VWF synthesis (type 3 von Willebrand disease [VWD]). The molecular pathways are likely to involve VWF binding partners, such as integrin αvβ3, and components of Weibel-Palade bodies, such as angiopoietin-2 and galectin-3, whose storage is regulated by VWF; these converge on the master regulator of angiogenesis and endothelial homeostasis, vascular endothelial growth factor signaling. Recent studies suggest that the roles of VWF may be tissue specific. The ability of VWF to regulate angiogenesis has clinical implications for a subset of VWD patients with severe, intractable gastrointestinal bleeding resulting from vascular malformations. In this article, we review the evidence showing that VWF is involved in blood vessel formation, discuss the role of VWF high-molecular-weight multimers in regulating angiogenesis, and review the value of studies on BOEC in developing a precision medicine approach to validate novel treatments for angiodysplasia in congenital VWD and acquired von Willebrand syndrome.

von Willebrand factor is a useful biomarker for liver fibrosis and prediction of hepatocellular carcinoma development in patients with hepatitis B and C

Background

Several noninvasive biomarkers are available for diagnosing liver fibrosis stage and predicting hepatocellular carcinoma (HCC) development in patients with chronic hepatitis and liver cirrhosis. However, these biomarkers are not sufficiently accurate. Recently, von Willebrand factor (VWF) has been related to angiogenesis and apoptosis. Furthermore, VWF is associated with hepatic spare ability and HCC.

Objective

We aimed to determine whether VWF is a potential biomarker for liver fibrosis and HCC development.

Methods

Two hundred and twelve patients with chronic hepatitis B and C were recruited. VWF antigen (VWF: Ag) levels in each patient were determined via enzyme-linked immunosorbent assay. Univariable and multivariable analyses were used to determine the risk factor of HCC.

Results

The VWF: Ag levels were higher in patients with severe liver fibrosis stage and/or HCC development than in those without. The area under the curve of VWF: Ag for diagnosis of severe liver fibrosis stage was 0.721. Multivariable analysis showed that only VWF: Ag was a predictive biomarker for HCC development.

Conclusions

VWF: Ag is related to liver fibrosis and may be useful for predicting HCC development. VWF is a potentially useful biomarker to diagnose severe liver fibrosis and predict HCC development.

Gastrointestinal Bleeding in Native and Prosthetic Valve Disease

Gastrointestinal bleeding with severe aortic stenosis was originally described in the 1950s by Heyde, although for years, the association was debated. Further discovery of mechanisms and the ubiquity and severity of acquired von Willebrand syndrome in the left ventricular assist device therapy have removed any doubts. At this time, gastrointestinal bleeding from intestinal angiodysplasia in patients with turbulence-related proteolysis of the highest molecular weight multimers of von Willebrand factor is now known to occur in patients with aortic stenosis, and also subaortic obstruction and associated mitral insufficiency in hypertrophic cardiomyopathy, isolated mitral and aortic insufficiency, endocarditis, and in patients with prosthetic valve dysfunction, either from stenosis or insufficiency. The degree of loss of high molecular weight multimers correlates with lesion severity, and tests of von Willebrand factor function have been proposed as important biomarkers of the severity of valve dysfunction, including in-lab testing for paravalvular leak during transcatheter aortic valve replacement. Bleeding tends to recur after endoscopic or surgical therapy, but cardiac repair is curative in the great majority.

Von Willebrand factor multimer quantitation for assessment of cardiac lesion severity and bleeding risk

BACKGROUND

von Willebrand factor (VWF) multimer quantitation has been utilized in the assessment of valvular heart disease, however, there is no standardized method for quantitation. We compared three methods of assessment which utilized a normal plasma control.

METHODS

We analyzed 476 samples and their control plasma from 368 patients with valvular heart disease, hypertrophic cardiomyopathy, or LVAD therapy, and 27 normal subjects. VWF multimers were assessed as normalized VWF multimer ratios (NMR) of gel bands >15/2-15 (NMR15) or gel bands >10/2-10 (NMR10). Associations of VWF laboratory and multimeric assessments with cardiac lesion severity and acquired bleeding were investigated.

RESULTS

Abnormal multimers were present in 78% of patients with moderate to severe hemodynamic abnormalities compared to 19% of patients with normal or mildly abnormal hemodynamics. NMR showed strong association with severe cardiac lesions (NMR15: OR 15.29, CI 9.04-27.18; NMR10: OR 14.18, CI 8.88-23.21). PFA-CADP was strongly associated with moderate to severe cardiac lesions (OR 14.91, CI 9.08-24.50). PFA-CADP and NMR15 showed excellent ability to discriminate ≥moderate (AUC 0.86, CI 0.83-0.89 and 0.83, CI 0.79-0.87 respectively) and severe cardiac lesions (AUC 0.84, CI 0.81-0.88 and 0.85, CI 0.81-0.88 respectively). NMR was less strongly associated with bleeding (OR 4.01 for NMR10, CI 2.49-6.58).

CONCLUSION

Quantification of VWF multimers may provide clinical utility in circumstances where clinical estimation of cardiac lesion severity is challenging, such as with dysfunctional prosthetic valves. The presence of abnormal VWF multimers is associated with bleeding, however further quantitation provided only modest improvement in risk stratification.

Gastrointestinal angiodysplasia and bleeding in von Willebrand disease

Von Willebrand disease (VWD), the most common genetic bleeding disorder, is characterised by a quantitative or qualitative defect of von Willebrand factor (VWF). Patients with VWD suffer from mucocutaneous bleeding, of severity usually proportional to the degree of VWF defect. In particular, gastrointestinal bleeding associated with angiodysplasia is often a severe symptom of difficult management. This review focuses on the pathophysiology, diagnosis and treatment of VWD-associated gastrointestinal angiodysplasia and related bleeding.

Systemic Octreotide Therapy in Prevention of Gastrointestinal Bleeds Related to Arteriovenous Malformations and Obscure Etiology in Atrial Fibrillation

OBJECTIVES

The present study describes the use of octreotide (OCT) in patients with atrial fibrillation (AF) receiving oral anticoagulation (OAC) who have gastrointestinal (GI) bleeding related to arteriovenous malformations (AVMs), as well as its effect on OAC tolerance and subsequent rebleeding.

BACKGROUND

AVMs cause significant GI bleeding, especially in patients with AF who are receiving OAC for stroke prevention. OCT has been shown to minimize recurrent GI bleeds related to AVMs.

METHODS

In a multicenter, observational study, 38 AF patients with contraindications to OAC because of AVM-related GI bleeding were started on 100 μg of subcutaneous OCT twice daily. OAC was resumed in all patients within 48 h. Incidence of recurrent GI bleeds was calculated, and hemoglobin levels were recorded at enrollment and at 3 and 6 months' follow-up.

RESULTS

After a median follow-up of 8 months, 36 patients (mean age 69 ± 8.0 years; mean CHA₂DS₂-VASc score 3 ± 1 and mean HAS-BLED score 3 ± 1) were available for analysis. All were able to successfully resume OAC, and 28 of 36 (78%) remained on OAC at the conclusion of the study, whereas 8 underwent left atrial appendage closure with subsequent OAC discontinuation. No systemic thromboembolic events occurred in follow-up. Of the 28 patients who continued receiving OAC, 19 (68%) were free of recurrent GI bleed, 4 had minor GI bleeds, 4 required transfusion, and 1 required colectomy for GI bleeding. Mean hemoglobin levels in all patients receiving OAC were significantly higher at 3- and 6-month follow-up than at baseline (p < 0.001).

CONCLUSIONS

Subcutaneous OCT therapy is an attractive option in AF patients receiving OAC who have AVM-related GI bleeds. It allows successful reinitiation of OAC as a bridge to left atrial appendage exclusion or short-term relief from bleeding.

Thalidomide for the Treatment of Gastrointestinal Bleeding Due to Angiodysplasia in a Patient with Glanzmann's Thrombasthenia

Angiodysplasia is a frequent cause of persistent gastrointestinal (GI) hemorrhage in elderly patients. Although GI bleeding isn't the most common manifestation in patients with bleeding disorders, when present, it represents a challenging complication. We describe a 62-year-old patient with Glanzmann's thrombasthenia, who used thalidomide for severe and recurrent GI bleeding. For 6 months, the patient experienced temporary control of GI bleeding with thalidomide in a daily oral dose of 100 mg. The anti-angiogenic effects of thalidomide have recently been explored by several groups, particularly in the management of bleeding from angiodysplasia, including cases with von Willebrand disease. Here, we review the relevant descriptions of the use of thalidomide in this situation, and also discuss potential reasons why we observed only a temporary control of the GI bleeding in our patient, such as the use of low-dose regimen due to limitations posed by thalidomide side effects.

Angiodysplasia in von Willebrand Disease: Understanding the Clinical and Basic Science

Severe and intractable gastrointestinal bleeding caused by angiodysplasia is a debilitating problem for up to 20% of patients with von Willebrand disease (VWD). Currently, the lack of an optimal treatment for this recurrent problem presents an ongoing challenge for many physicians in their management of affected patients. Over the past few years, studies have pointed to a regulatory role for the hemostatic protein, von Willebrand factor (VWF), in angiogenesis, providing a novel target for the modulation of vessel development. This article will review the clinical implications and molecular pathology of angiodysplasia in VWD.

Recombinant von Willebrand factor for severe gastrointestinal bleeding unresponsive to other treatments in a patient with type 2A von Willebrand disease: a case report

A recombinant von Willebrand factor (rVWF) was recently approved in the United States for on-demand treatment and control of bleeding episodes in adults with von Willebrand disease (VWD). In contrast to plasma-derived VWF products available in the United States, rVWF does not contain factor VIII (FVIII). To date, there is no published experience of rVWF in clinical practice. We report the acute and prophylactic use of rVWF in a patient with VWD type 2A and severe gastrointestinal bleeding. Dosing with plasma-derived VWF/FVIII concentrates was constrained by FVIII accumulation; the bleeding was unresponsive, and multiple red blood cell transfusions were required. After initiation of rVWF (4200 IU every other day), bleeding symptoms subsided, and no red blood cell transfusions were required during more than 3 months of prophylactic therapy (most recent dosage: 2800 IU every other day). rVWF may be effective in the prevention, as well as treatment, of severe bleeding symptoms in VWD.

Laboratory monitoring of replacement therapy for major surgery in von Willebrand disease

Von Willebrand disease (VWD) is an inherited haemorrhagic disorder caused by a quantitative or qualitative defect of von Willebrand factor (VWF), a multimeric plasma glycoprotein that plays a key role in platelet adhesion to the subendothelium and acts as a carrier of factor VIII (FVIII) in blood. Patients with VWD experience bleeding symptoms that are mainly localized in mucous membranes and soft tissues, and their severity depends on the degree of the primary reduction in VWF and the secondary deficiency of FVIII in plasma. Because VWD patients are also at increased risk of perioperative bleeding, a prophylactic treatment aimed to correct the dual haemostatic defect (i.e. VWF and FVIII) is warranted. This review summarizes knowledge on the current management of patients undergoing major surgery, focusing on the peri-surgical laboratory monitoring of replacement therapy with VWF/FVIII concentrates. We suggest to monitor plasma levels of FVIII coagulant activity in the postoperative period rather than a surrogate maker of platelet-binding VWF activity as the ristocetin cofactor assay and its recent modifications.

Debate: creating adequate pulse with a continuous flow ventricular assist device: can it be done and should it be done? Probably not, it may cause more problems than benefits!

PURPOSE OF REVIEW

The feasibility and benefits of creating adequate pulsatility with continuous flow left ventricular assist devices (LVADs) have long been debated. This review discusses recent technical and clinical findings to answer whether such intervention should be implemented in the standard patient management.

RECENT FINDINGS

Only a limited amount of pulsatility can be generated by periodic speed steps, both considerably smaller in flow increase and in pace rate than the natural circulation. Organ systems are not impeded in their normal function and even not in recovery by a continuous flow. Known problems such as gastrointestinal bleeding are not necessarily due to pulsatility per se, or not important for therapeutic progress, such as minor modifications of the arterial walls.

SUMMARY

The speculative benefits of augmented pulsatility with continuous flow LVADs could be overrated and are still incompletely evaluated. Potential risks that might arise from this strategy should be carefully weighed before implementing extensive pulsatility as standard patient management.

Usefulness of Von Willebrand Factor Activity Indexes to Predict Therapeutic Response in Hypertrophic Cardiomyopathy

Degraded by shear stress, loss of high-molecular-weight multimers of von Willebrand factor (VWF) correlates strongly with pressure gradient in aortic stenosis (AS) and obstructive hypertrophic cardiomyopathy (HC). We assessed VWF tests before and after interventions in HC and contrasted the severity of abnormalities in HC to patients with AS, mitral regurgitation, and left ventricular assist devices. Ninety patients with median (interquartile range) age 66 (53 to 72) years, 51% men, with HC had assessments of 3 VWF parameters and B-type natriuretic peptide before and after 26 discreet medical/pacing interventions, 22 alcohol septal ablations, and 28 ventricular septal myectomies. VWF multimers were abnormal in 87% of patients with obstructive HC versus 48% of patients with latent obstruction (p = 0.0001). VWF measurements correlated with peak instantaneous left ventricular outflow tract gradient, Spearman ρ 0.51 to 0.61, p <0.0001. For B-type natriuretic peptide, correlation with left ventricular outflow tract gradient was weaker, ρ = 0.37, p = 0.0005, but stronger with septal thickness or mitral E/e'. In pre-/post-medical treatment of HC, VWF multimers were abnormal in 73%/68% of patients, p = 0.74; pre-/post-septal ablation 74%/26%, p = 0.0035; and pre-/post-septal myectomy 75%/0%, p <0.0001. In obstructive HC, the degree VWF multimer loss was greater than in severe AS or severe mitral regurgitation and overlapped that seen in left ventricular assist devices. In conclusion, VWF activity indexes were predictably abnormal in patients with HC with resting obstruction to a degree where bleeding could be anticipated, accurately reflected gradient changes after intervention, and demonstrated complete normalization after septal myectomy.

Changes in bleeding patterns in von Willebrand disease after institution of long-term replacement therapy: results from the von Willebrand Disease Prophylaxis Network

Clinically, the leading symptom in von Willebrand disease (VWD) is bleeding, chiefly of mucosal type, for example, epistaxis, gingival, or gastrointestinal bleeding, and menorrhagia. In severe forms of VWD with secondary deficiency of factor VIII, spontaneous joint bleeding, resembling that observed in severe haemophilia A, may also be observed. The bleeding patterns of VWD can affect quality of life, and may be life-threatening. The von Willebrand Disease Prophylaxis Network is an international study group formed with the goal of investigating the role of prophylaxis in clinically severe VWD. The objective of the present study is to investigate the response to prophylaxis focusing primarily on epistaxis, joint bleeding, gastrointestinal bleeding, and heavy bleeding associated with menses. Data from 105 subjects, 10 enrolled in a prospective study and 95 in a retrospective study between 2008 and 2013, were available for analysis. The median annualized rate reductions in bleeding were significant for epistaxis (P < 0.0001), gastrointestinal bleeding (P = 0.0003), joint bleeding (P < 0.0001), and menorrhagia (P = 0.008). Doses on a group level were approximately the same prior to and during prophylaxis, but more patients with gastrointestinal bleeding had prophylaxis three or more times per week as well as higher dosages. Our study, which primarily used retrospective data, indicates that prospective studies are needed to better delineate the doses and dose intervals that should be used for prophylactic treatment of VWD.

Thalidomide for treatment of gastrointestinal bleedings due to angiodysplasia: a case report in acquired von Willebrand syndrome and review of the literature

INTRODUCTION

Acquired von Willebrand syndrome is a rare bleeding disorder and treatment of the associated gastrointestinal (GI) bleeding due to angiodysplasia is challenging.

AIM

The aim of this study was to present a new case on the successful use of thalidomide in a patient with acquired von Willebrand syndrome and recurrent angiodysplasia-related GI bleedings, and to conduct a literature review on the use of thalidomide in patients with GI angiodysplasia.

METHODS

A literature review was conducted, searching the electronic databases PubMed, Embase and Cochrane.

RESULTS

We present a 75-year-old woman with IgG MGUS-associated acquired von Willebrand syndrome (AVWS) who suffered from recurrent gastrointestinal (GI) bleedings and epistaxis. Treatment with immunoglobulins, desmopressin, Haemate-P and blood transfusions failed to achieve long-term haemostasis. Eventually, after these bleedings relapsed for almost a decade at 1- to 3-month intervals, thalidomide was prescribed. Since then, only one single nose bleed and one single melaena episode had occurred. She currently remains in remission of GI bleeds after 3 years and 3 months follow-up. The literature review revealed a beneficial effect of thalidomide in reducing GI bleeding due to angiodysplasia, including four case reports on inherited von Willebrand disease.

CONCLUSION

In conclusion, thalidomide can be a reasonable option for the treatment of recurrent GI bleeding due to angiodysplasia in AVWS and we report for the first time that refractory or relapsing GI bleeding in patients with AVWS can successfully be controlled with thalidomide.