The prevalence of symptomatic von Willebrand disease in primary care practice

Point-of-Care Testing in Patients with Hereditary Disorders of Primary Hemostasis: A Narrative Review

Inherited disorders of primary hemostasis, such as von Willebrand disease and congenital platelet disorders, can cause extensive, typically mucocutaneous bleeding. Assays to diagnose and monitor these disorders, such as von Willebrand factor activity assays and light transmission aggregometry, are performed in specialized hemostasis laboratories but are commonly not available in local hospitals. Due to the complexity and relative scarcity of these conventional assays, point-of-care tests (POCT) might be an attractive alternative in patients with hereditary bleeding disorders. POCTs, such as thromboelastography, are increasingly used to assess hemostasis in patients with acquired hemostatic defects, aiding clinical decision-making in critical situations, such as during surgery or childbirth. In comparison, the use of these assays in patients with hereditary hemostasis defects remains relatively unexplored. This review aims to give an overview of point-of-care hemostasis tests in patients with hereditary disorders of primary hemostasis. A summary of the literature reporting on the performance of currently available and experimental POCTs in these disorders is given, and the potential utility of the assays in various use scenarios is discussed. Altogether, the studies included in this review reveal that several POCTs are capable of identifying and monitoring severe defects in the primary hemostasis, while a POCT that can reliably detect milder defects of primary hemostasis is currently lacking. A better understanding of the strengths and limitations of POCTs in assessing hereditary defects of primary hemostasis is needed, after which these tests may become available for clinical practice, potentially targeting a large group of patients with milder defects of primary hemostasis.

Cost-effectiveness of Voncento prophylaxis vs on-demand treatment in von Willebrand disease in the United Kingdom

ABSTRACT

von Willebrand factor (VWF) concentrates may be required for on-demand treatment (ODT) or long-term prophylaxis (LTP) in von Willebrand disease (VWD). This study assesses the cost-effectiveness of LTP compared with ODT in patients with VWD treated with Voncento in the United Kingdom. A Markov structure was developed to estimate the quality-adjusted life years (QALYs) and costs of VWD treatment over a lifetime horizon. Treatment options included ODT or LTP. For both options, we assumed plasma-derived VWF/factor VIII 2.4:1 (Voncento) as the VWF product used. Clinical parameters were obtained from published literature and Voncento's summary characteristics. Utility weights were obtained from published literature. Costs (in 2021 GBP [£]) and outcomes were discounted annually by 3.5%. Sensitivity analyses were conducted. Three baseline annual bleed rate (ABR) scenarios (11, 26.5, and 39.6) were considered. In the base-case analyses, Voncento LTP resulted in lower costs (-£831 206) and greater QALYs (6.14) vs ODT. Savings were primarily due to reductions in product use required (-£529 571) and bleed-related other medical costs (-£301 352). Compared with ODT, LTP also resulted in 322.52 fewer major bleeds and 515.68 fewer minor bleeds over a lifetime horizon. Probabilistic sensitivity analyses showed dominance in 96.12% of simulations and cost-effectiveness in 97.68% of simulations. For the 39.6 ABR scenario also, LTP was dominant compared with ODT. Results suggest that Voncento LTP is more effective and cost saving than ODT in the United Kingdom for patients with VWD with higher ABR. Prophylaxis for patients with frequent bleeds is likely to be a cost-saving and effective strategy.

Plasma-Derived von Willebrand Factor/Factor VIII Concentrate (Haemate P) in von Willebrand Disease: A Systematic Review and Pharmacovigilance Update

BACKGROUND

Von Willebrand disease (VWD) is an inherited bleeding disorder caused by deficient or dysfunctional von Willebrand factor (VWF). VWF replacement therapy is indicated in VWD management.

METHODS

This systematic review was conducted to evaluate all available evidence of the efficacy, safety, dosing and consumption of pasteurized plasma-derived human coagulation FVIII/human VWF (pdVWF/FVIII; Haemate P/Humate-P) concentrate for on-demand (OD) treatment, surgical prophylaxis and long-term prophylaxis of patients with VWD. A systematic search was performed in MEDLINE and Cochrane Library databases to identify studies (7 June 1982-31 May 2023) reporting the use of pdVWF/FVIII in VWD according to predefined selection criteria. Pharmacovigilance data were also retrieved for the same period.

RESULTS

Fifteen studies were identified, 12 being observational and three interventional. Efficacy and safety assessments and treatment protocols varied across the studies which hindered direct comparisons. Haemostatic efficacy of pdVWF/FVIII was rated excellent/good for OD treatment in 95%-98% of bleeds and in 94%-100% of surgeries. In two separate studies, prophylactic efficacy was rated excellent/good in 100% of treatment cycles. Where reported, median annualized bleeding rates decreased from 3-24 prior prophylaxis to 0.5-6 during prophylaxis. Analysis of pharmacovigilance safety reports showed that pdVWF/FVIII was associated with a low rate of adverse events.

CONCLUSIONS

This systematic literature review and analysis of pharmacovigilance data summarize evidence of over 40 years of clinical use of pdVWF/FVIII, supporting its safety and efficacy in VWD.

Development and validation of an algorithm to better identify pregnant women with inherited bleeding disorders within electronic health records

BACKGROUND

When using electronic health records (EHRs) to conduct population-based studies on inherited bleeding disorders (IBDs), using diagnosis codes alone results in a high number of false positive identifications.

OBJECTIVE

The objective of this study was to develop and validate an algorithm that uses multiple data elements of EHRs to identify pregnant women with IBDs.

METHODS

The population included pregnant women who had at least one live birth or fetal death (>20 weeks gestation) at our institution from 2016 to 2023. We iteratively developed the algorithm using a composite criteria of encounter diagnosis codes, laboratory and medications data. We assessed the performance of the algorithm for sensitivity and positive predictive value (PPV) using our local registry and manual chart review.

RESULTS

Using the source population between 2016 and 2020, the initial algorithm identified 25 pregnant women with IBDs. Eight women with a known diagnosis of an IBD were missed resulting in a sensitivity of 75.8 % and a PPV of 100 %. We revised the algorithm to remove certain IBD diagnosis codes that resulted in contamination and added additional criteria to improve the sensitivity. The revised algorithm had a sensitivity of 97.0 % and a PPV of 91.4 %. The revised algorithm was validated using the source population between 2021 and 2023 and had a sensitivity of 97.1 % and a PPV of 91.7 %.

CONCLUSION

This study demonstrates the utility of an algorithm to better identify pregnant women with specific types of IBD, mainly hemophilia and hemophilia carriers, and von Willebrand disease, within EHRs.

A Ten-Year Experience with the Diagnosis of Von Willebrand Disease in Mexico Based on a Cost-Effective Strategy

BACKGROUND

Von Willebrand disease (VWD), is the most common inherited bleeding disorder worldwide, but its diagnosis is complicated, expensive, and poorly evaluated in several countries.

OBJECTIVE

To report our long-term experience with the diagnosis of VWD based on a cost-effective strategy.

METHODS

We studied 802 Mexican patients, men and women, children, and adults, with clinical suspicion of VWD. The following tests were performed: blood count, bleeding time, prothrombin time, activated partial thromboplastin time, fibrinogen concentration, VWF antigen, ristocetin cofactor activity, collagen binding assay, ristocetin-induced platelet aggregation, FVIII activity, and VWF multimers analysis.

RESULTS

VWD was diagnosed in 639 patients; 582 had type 1 VWD (91.1%). Type 2 VWD was found in 52 patients (8.1%). Type 2A was present in 25 cases (48.1%), while types 2B and 2 M accounted for 21 (40.4) and six (11.5%) cases, respectively. Type 3 VWD was present in five patients (0.8%). The mean age of patients with VWD was 25.3 years (range: 2-71) for males and 22.1 (range: 1-54) for females. The diagnosis was inconclusive in 40 cases (5.0%) and was discarded in 123 (15.3%). Blood group O was the most common among patients with VWD.

CONCLUSION

Using a low-cost diagnostic strategy, we confirmed that VWD is as common in Mexico as in other countries. Review of the patient's history is mandatory when VWD is suspected, although laboratory confirmation may be difficult and expensive. The consequences of a lack of accurate and timely diagnosis affect the promptness and quality of treatment.

The future of siRNA-mediated approaches to treat von Willebrand disease

INTRODUCTION

The clinical management of the inherited bleeding disorder von Willebrand disease (VWD) focuses on normalizing circulating levels of von Willebrand factor (VWF) and factor VIII (FVIII) to prevent or control bleeding events. The heterogeneous nature of VWD, however, complicates effective disease management and development of universal treatment guidelines.

AREAS COVERED

The current treatment modalities of VWD and their limitations are described and why this prompts the development of new treatment approaches. In particular, RNA-based therapeutics have gained significant interest because of their ability to reversibly alter gene expression with long-term efficacy. In the field of VWD, small-interfering RNAs (siRNAs) have been explored through various strategies to improve disease phenotypes. These different approaches are discussed as well as their potential impact on reshaping the future therapeutic landscape.

EXPERT OPINION

Current treatments for VWD often require frequent intravenous administration of VWF concentrates or desmopressin, with only short-term benefits. Moreover, remaining circulating mutant VWF can cause detrimental effects. Allele-selective siRNA-based therapies could provide more reliable and long-term disease correction by specifically targeting mutant VWF. This approach could be applied to a large part of the population aligning with the growing emphasis on personalized treatment and patient-centered care in VWD management.

Genetic insights and therapeutic avenues: unraveling the role of polyunsaturated fatty acids as mediators between hypothyroidism and Von Willebrand disease through Mendelian randomization

Background

Previous observational studies have shown that Hypothyroidism is associated with Von Willebrand Disease (VWD), but the causal relationship has not been confirmed because of conflicting findings and confounding by mixing factors. There are also some studies suggesting that polyunsaturated fatty acids (PUFA) may be one of the potential mediators. In this study, we used a Mendelian randomization study to analyze the causal relationship between Hypothyroidism and VWD and to investigate whether polyunsaturated fatty acids mediate the effects of Hypothyroidism on VWD.

Methods

Using a large publicly available genome-wide association study of predominantly European ancestry to obtain data on Hypothyroidism, VWD, and PUFA, we conducted a two-sample Mendelian randomization study to assess the causal relationship between Hypothyroidism and VWD and assess the potential role of Polyunsaturated fatty acids in mediating the causal pathway between Hypothyroidism and VWD. Finally, we also inferred reverse causality between VWD and Hypothyroidism. Inverse variance weighting (IVW) was the primary analytical method.

Results

We found that Hypothyroidism may be negatively causally associated with the development of VWD and that PUFA have a role in mediating role in this process (the ratio of the mediating effect: 24.33%). The causal effects of Hypothyroidism and PUFA on VWD remained significant (p < 0.05) after correction of each other by MVMR.

Conclusion

Our study unveils a novel negative correlation between hypothyroidism and VWD, further enriched by the discovery of partial mediation by PUFA. This groundbreaking finding not only advances our comprehension of VWD etiology but also opens promising avenues for its control and treatment. By elucidating the intricate interplay between hypothyroidism, PUFA, and VWD, our research pioneers a paradigm shift in therapeutic approaches, offering fresh perspectives for the management of this complex disorder.

Genotyping R1336X and Eliminating the Pseudogene Amplification in Type 3 von Willebrand Disease Patients

Among inherited bleeding disorders, von Willebrand disease (VWD) is the most common disease worldwide. Type 3, the most severe form, is more prevalent in developing countries primarily due to consanguineous marriages. The enormous size of the von Willebrand factor gene, different kinds of mutations, and a partial unprocessed pseudogene make variation detection more difficult. To distinguish the VWF gene and the pseudogene sequence and prevent pseudogene amplification, it is necessary to utilize a suitable method. In this study, 42 unrelated VWD type 3 patients and 22 normal controls were included. Tetra-primer ARMS-PCR was applied for genotyping the single nucleotide variation, R1336X located on exon 28, which overlaps the pseudogene. The High percentage of heterozygotes (17% in VWD patients and 13% in controls) raised the suspicion of concomitant amplification of the VWF gene and it's pseudogene due to similarity in their primer-binding site sequence. To overcome this issue, we applied a two-step method using touch-down PCR followed by a tetra-primer ARMS-PCR. All cases with the heterozygous pattern on the first tetra-primer ARMS PCR were found to be normal homozygotes. In type 3 VWD patients genotyping is essential in decreasing the incidence of the disease, but the presence of a pseudogene with 97% homology makes it difficult. Applying appropriate methods that combine touch-down PCR and tetra-primer ARMS-PCR in terms of reliability, sensitivity, and accuracy can help to eliminate the pseudogene effect and diagnose more affected individuals.

Current and emerging therapies as potential treatment for people with von Willebrand disease

INTRODUCTION

Von Willebrand disease (VWD) reflects the most common inherited bleeding disorder, arising from defects or deficiencies in the von Willebrand factor (VWF). VWD treatment mostly relies on the replacement of missing or defective VWF, but additional ('adjunct') therapies are useful in select patients/situations. Patients with VWD are often misdiagnosed and therefore non-optimally managed.

AREAS COVERED

We provide a narrative review, following relevant literature searches in PubMed related to the topic up to September 2024. After an overview of VWF, VWD, and current treatments, we explore the use of nonstandard or emerging therapies for VWD. For example, FVIII replacement or antibody-based FVIII bypassing strategies (e.g. emicizumab) may prove useful in some cases or in initial treatment of certain VWD patients, including those with type 2N or 3 VWD, or those with inhibitors. Additional emerging therapies may also be useful, including hemostasis rebalancing agents.

EXPERT OPINION

Just as hemophilia is experiencing a renaissance of treatment options, so too will the landscape of VWD treatment change over time. This will be fueled by the concept of personalized treatment, meaning potentially different treatments for different VWD patients, or for given patients according to treatment aims.

Preoperative Testing

Preoperative medical evaluation can minimize inefficiencies and improve outcomes. Thoughtful use of preoperative testing can aid in that effort, but, conversely, indiscriminate testing can detract from it. The United Kingdom National Institute for Health Care and Excellence, European Society of Anaesthesiology, and American Society of Anesthesiologists (ASA) have all stated that routine preoperative testing is not supported by evidence. Testing is supported only when clinical indications are present. Particularly in low-risk patients, such as those with an ASA classification of 1 or 2 who are undergoing ambulatory procedures, evidence suggests that preoperative testing fails to reduce the risk of complications.

Analytical and Clinical Validation of a Non-Ristocetin Based VWF Assay on 2 Automated Analyzers in a Large Reference Laboratory

BACKGROUND

Historically, von Willebrand factor (VWF) activity assays utilized ristocetin despite limitations including poor limits of detection and high imprecision. Newer VWF activity assays such as the INNOVANCE® VWF Ac assay, however, do not rely on ristocetin to measure platelet-dependent VWF function. The purpose of this study was to evaluate the analytical and clinical performance of the Siemens Healthineers INNOVANCE VWF Ac Assay on the Siemens BCS® XP and the Sysmex® CS-2500 systems in a large reference laboratory setting.

METHODS

Performance indicators for the INNOVANCE VWF Ac assay were the limit of quantitation (LoQ), precision, and method comparison. Method comparison studies were performed using remnant plasma patient samples from routine coagulation tests and analyzed using both the INNOVANCE VWF Ac assay and the Siemens Healthineers ristocetin-dependent BC von Willebrand Reagent.

RESULTS

Evaluation of the INNOVANCE VWF Ac assay on the BCS® XP and CS-2500 systems demonstrated good precision and a lower LoQ compared to the BC von Willebrand Reagent. Method comparisons support the use of the INNOVANCE VWF Ac assay on the BCS® XP and CS-2500 systems to measure platelet-dependent VWF function. The INNOVANCE VWF Ac assay was able to further assist in von Willebrand disease classification in 6/7 (86%) samples when the result was below the LoQ for the BC von Willebrand Reagent (ristocetin cofactor activity).

CONCLUSIONS

These data are consistent with the 2021 American Society of Hematology/International Society on Thrombosis and Haemostasis/National Hemophilia Foundation/World Federation of Hemophilia von Willebrand disease guidelines that suggest using newer assays such as the INNOVANCE VWF Ac assay in place of ristocetin cofactor activity assays.

Review of interventions and effectiveness for heavy menstrual bleeding in women with moderate and severe von Willebrand disease

INTRODUCTION

Women with VWD have an increased risk of gynaecological complications due to haemostatic challenges of menstruation.

AIM

Review gynecological bleeding symptoms and their management in women with moderate-severe VWD.

MATERIALS AND METHODS

Retrospective cohort analysis of prospectively collected data for women with moderate and severe VWD attending a joint multidisciplinary clinic between January 2010 and December 2020. Data was collected from electronic patient records on response to treatment options using PBAC, quality of life (QoL) assessment using SF-36 scores, haemoglobin and ferritin in comparison to pre-treatment values.

RESULTS

Of the 67 women managed in the clinic; all reported heavy menstrual bleeding (HMB). Combination therapy with concurrent hormonal agents and tranexamic acid was required in 80% of women. There was an overall 64% improvement in PBAC scores in the first year, reflecting on QoL with 35% improvement in SF-36 score and correction of anaemia in 21% of cases. The cumulative effect of continued treatment culminated in greater reduction of blood loss, with an overall 71% improvement in PBAC scores by 5 years. One in 10 women required surgical treatment for a gynaecological pathology. Non-compliance was the cause of excessive unscheduled bleeding in 50% of adolescents. After 3 years, one in five women experienced a relapse of symptom, of whom 46% became perimenopausal and 54% discontinued hormonal treatments due to concerns about fertility, hair loss and weight gain.

CONCLUSION

Management of HMB requires careful monitoring and follow-up by MDT with close collaboration between the gynaecology team and HTC. Control of HMB often requires a combination therapy.

Application of genetic testing for the diagnosis of von Willebrand disease

von Willebrand disease (VWD) is the most frequent inherited bleeding disorder, with an estimated symptomatic prevalence of 1 per 1000 in the general population. VWD is characterized by defects in the quantity, quality, or multimeric structure of von Willebrand factor (VWF), a glycoprotein being hemostatically essential in circulation. VWD is classified into 3 principal types: low VWF/type 1 with partial quantitative deficiency of VWF, type 3 with virtual absence of VWF, and type 2 with functional abnormalities of VWF, being classified as 2A, 2B, 2M, and 2N. A new VWD type has been officially recognized by the ISTH SSC on von Willebrand factor which has also been discussed by the joint ASH/ISTH/NHF/WFH 2021 guidelines (ie, type 1C), indicating patients with quantitative deficiency due to an enhanced VWF clearance. With the advent of next-generation sequencing technologies, the process of genetic diagnosis has substantially changed and improved accuracy. Therefore, nowadays, patients with type 3 and severe type 1 VWD can benefit from genetic testing as much as type 2 VWD. Specifically, genetic testing can be used to confirm or differentiate a VWD diagnosis, as well as to provide genetic counseling. The focus of this manuscript is to discuss the current knowledge on VWD molecular pathophysiology and the application of genetic testing for VWD diagnosis.

von Willebrand disease

von Willebrand disease (VWD) is the most common inherited bleeding disorder. The disorder is characterized by excessive mucocutaneous bleeding. The most common bleeding manifestations of this condition include nosebleeds, bruising, bleeding from minor wounds, menorrhagia or postpartum bleeding in women as well as bleeding after surgery. Other less frequent symptoms include gastrointestinal bleeding, haematomas or haemarthroses. VWD pathophysiology is complex and results from defects in von Willebrand factor (VWF) glycoprotein. Quantitative deficiencies are responsible for type 1 VWD with a partial decrease of VWF and type 3 with the complete absence of VWF. Qualitative abnormalities cause type 2 VWD, being further divided into types 2A, 2B, 2M and 2N. Although common, VWD is at risk of misdiagnosis, overdiagnosis and underdiagnosis owing to several factors, including complex diagnosis, variability of bleeding symptoms, presence of external variables (blood groups and other physiological modifiers such as exercise, thyroid hormones, oestrogens, and ageing), and lack of disease awareness among non-specialist health-care providers. Establishing the correct VWD diagnosis requires an array of specialized phenotypic assays and/or molecular genetic testing of the VWF gene. The management of bleeding includes increasing endogenous VWF levels with desmopressin or infusion of exogenous VWF concentrates (plasma-derived or recombinant). Fibrinolytic inhibitors, topical haemostatic agents and hormonal therapies are used as effective adjunctive measures.

Hereditary hemorrhagic telangiectasia may be the most morbid inherited bleeding disorder in women

ABSTRACT

Hereditary hemorrhagic telangiectasia (HHT) is the second-most common inherited bleeding disorder (BD) worldwide and remains without approved therapies. HHT causes serious mucosal bleeding resulting in severe iron-deficiency anemia, major psychosocial complications, and visceral arteriovenous malformations in the brain, lung, and liver, which can cause life-threatening hemorrhagic complications. No study has examined the relative morbidity of HHT and von Willebrand disease (VWD), which is the most common inherited BD in women. We performed an observational cohort study of women with HHT or VWD, comparing a representative sample of 100 randomly selected women with HHT to 100 randomly selected age-matched women with VWD. In HHT vs VWD, recurrent epistaxis and gastrointestinal bleeding were more likely (odds ratio [OR], 32.73 [95% confidence interval, 13.81-71.80]; P < .0001 and 5.69 [2.59-12.89]; P < .0001) and heavy menstrual bleeding was less likely (OR, 0.32 [0.18-0.57]; P < .0001). Iron-deficiency anemia was significantly more likely, and the lowest hemoglobin was significantly lower in HHT than in VWD. The odds of iron infusion dependence, requirement for red cell transfusion, and hemostatic surgical procedures were significantly higher-17-fold, threefold, and eightfold higher, respectively-and hospital admissions to manage disease complications were both ∼14 times more frequent in women with HHT vs those with VWD. In conclusion, much higher disease-related morbidity, mortality, and health care use were observed in women with HHT vs VWD, providing evidence that HHT may be the most clinically significant inherited BD in women. Given the vast gap in research funding for HHT compared with both hemophilia (a disease primarily of men) and VWD, these findings have significant implications for gender equity in hematology.

Type 2M/2A von Willebrand disease: a shared phenotype between type 2M and 2A

ABSTRACT

Four variants have been continuously subjected to debate and received different von Willebrand disease (VWD) classifications: p.R1315L, p.R1315C, p.R1374H, and p.R1374C. We chose to comprehensively investigate these variants with full set of VWD tests, protein-modeling predictions and applying structural biology. Patients with p.R1315L, p.R1315C, p.R1374H, and p.R1374C were included. A group with type 2A and 2M was included to better understand similarities and differences. Patients were investigated for phenotypic assays and underlying disease mechanisms. We applied deep protein modeling predictions and structural biology to elucidate the causative effects of variants. Forty-three patients with these variants and 70 with 2A (n = 35) or 2M (n = 35) were studied. Patients with p.R1315L, p.R1374H, or p.R1374C showed a common phenotype between 2M and 2A using von Willebrand factor (VWF):GPIbR/VWF:Ag and VWF:CB/VWF:Ag ratios and VWF multimeric profile, whereas p.R1315C represented a type 2M phenotype. There was an overall reduced VWF synthesis or secretion in 2M and cases with p.R1315L, p.R1374H, and p.R1374C, but not in 2A. Reduced VWF survival was observed in most 2A (77%), 2M (80%), and all 40 cases with p.R1315L, p.R1374H, and p.R1374C. These were the only variants that fall at the interface between the A1-A2 domains. p.R1315L/C mutants induce more compactness and internal mobility, whereas p.R1374H/C display a more extended overall geometry. We propose a new classification of type 2M/2A for p.R1315L, p.R1374H, and p.R1374C because they share a common phenotype with 2M and 2A. Our structural analysis shows the unique location of these variants on the A1-A2 domains and their distinctive effect on VWF.

Diagnosis and treatment of von Willebrand disease in 2024 and beyond

MANUSCRIPT BACKGROUND AND AIM

The diagnosis and clinical care of patients with von Willebrand disease (VWD) has continued to evolve since the characterization of the von Willebrand factor (VWF) gene in 1985. This condition is almost certainly the most common inherited bleeding disorder, and the major symptomatic burden of the disease is experienced by females during their reproductive years. Diagnosis relies on the identification of a personal and family history of excessive mucocutaneous bleeding, and laboratory features consistent with quantitative and/or qualitative abnormalities of VWF. This review focuses on three aspects of VWD management, with current updates and a look into the future.

MANUSCRIPT THEMES

First, we will address the role of genetics in the diagnosis and possible therapies for VWD. With current technologies, VWD genetic diagnosis is usually confined to the confirmation of type 2 subtypes of the disease and type 3 VWD analysis for family planning. While type 3 VWD is a potential candidate for the application of gene therapy, no treatments are currently close to entering the clinic. Second, the peri-procedural management of patients with VWD remains an important element of care. The choice of product, its dose and schedule all require careful consideration depending upon the type and disruptive nature of the planned procedure. Lastly, in addition to gene therapy, several other novel therapeutic interventions are also being developed for bleeding and prophylaxis in VWD. These include a VWF aptamer interfering with VWF clearance and bioengineered forms of VWF.

Diagnosis and treatment challenges in lower resource countries: State-of-the-art

The 2022 World Federation of Haemophilia Annual Global Survey (AGS) reports that 454,690 patients with inherited bleeding disorders (IBD) have been identified globally. While this represents noteworthy progress, haemophilia epidemiology data indicate that 75% of people with inherited bleeding disorders living in low-income and low-to-middle-income countries have yet to be diagnosed. The AGS also revealed that 11 billion clotting factor units are available to treat haemophilia A and B globally. Due to a lack of finance, these treatments are unavailable to haemophilia in low-income countries with a consequence lack of access equity for haemophilia treatment in these communities. This sobering reality is not limited to haemophilia but applies to von Willebrand Disease (VWD). While VWD is the most prevalent IBD, only 103,844 people living with this condition have been diagnosed globally. Of the diagnosed patients, only a fraction live in low- or middle-income countries. Moreover, the majority of VWD patients are still treated sub-optimally without replacement therapies or prophylaxis, both of which are now accepted as global standards of care. In this state-of-the-art review, the authors reflect on three issues. First, the minimum elements required to diagnose haemophilia in a resource-constrained setting are identified. Second, this review points to the critical stakeholders and outlines their roles in removing access to haemophilia treatment barriers. Finally, the authors examine von Willebrand disease's ongoing diagnostic and treatment challenges and compare these to haemophilia. With the rapidly evolving novel therapies, the therapeutic landscape of all IBD will likely change for the better.

Exposure-Response Relationship between VWF/FVIII Activity and Spontaneous Bleeding Events Following Recombinant VWF Prophylaxis in Severe VWD

Background  Recombinant von Willebrand factor (rVWF, vonicog alfa, Takeda Pharmaceuticals USA) is indicated in adults diagnosed with von Willebrand disease (VWD). In this study, the exposure-response (ER) relationship between VWF activity (VWF:RCo) or factor VIII activity (FVIII:C) and spontaneous bleeding events (BEs) was evaluated in adults with severe VWD receiving rVWF prophylaxis for up to 1 year. Methods  This secondary analysis included 23 patients receiving rVWF prophylaxis in the open-label, phase 3 prophylaxis trial (NCT02973087). Population pharmacokinetic (PK) and PK/pharmacodynamic (PD) models were used to characterize VWF activity and endogenous FVIII:C, and PK/PD simulations were linked to spontaneous BEs to develop an ER model. Results  None of the five patients with VWD types 1 or 2A/B experienced spontaneous BEs. Five of 18 patients with VWD type 3 experienced ≥1 spontaneous BEs. An ER relationship was observed whereby higher VWF:RCo levels were associated with a numerically lower spontaneous BE risk ( p  < 0.10). This relationship was independent of patients' pretrial VWF treatment. A statistically significant ER relationship was observed after accounting for relevant data (average ± standard error exposure estimate for VWF:RCo over 24 hours prior to the spontaneous BE: -0.043 ± 0.021, p  = 0.041). The model-generated hazard ratio for a 10 IU/dL increment in the average exposure of VWF:RCo 24 hours before a spontaneous BE was 0.651 (95% confidence interval: 0.431-0.982). Conclusions  This ER analysis suggests a causal association between VWF:RCo and spontaneous BEs, with an increase of VWF:RCo exposure leading to a decrease in spontaneous BE risk.

Targeting a higher plasma VWF level at time of delivery in pregnant individuals with von Willebrand disease: Outcomes at a single-institution cohort study

INTRODUCTION

Guidelines on the management of pregnant individuals with von Willebrand disease (VWD) at the time of delivery recommend that von Willebrand factor (VWF) and factor VIII:C (FVIII:C) levels be ≥50% to prevent postpartum haemorrhage (PPH). Yet, high PPH rates persist despite these levels or with prophylactic factor replacement therapy to achieve these levels.

AIMS

The current practice at our centre has been to target peak plasma VWF and FVIII:C levels of ≥100 IU/dL at time of delivery. The objective of this study was to describe obstetric outcomes in pregnant individuals with VWD who were managed at our centre.

METHODS

Demographics and outcomes on pregnant individuals with VWD who delivered between January 2015 and April 2023 were collected.

RESULTS

Forty-seven singleton deliveries (among 41 individuals) resulting in 46 live births and one foetal death were included. Twenty-one individuals had at least one prior birth by the start date of this study, of which 11 (52.4%) self-reported a history of PPH. Early PPH occurred in 12.8% (6/47) of deliveries. Two individuals required blood transfusion, of which one also had an unplanned hysterectomy and transfer to ICU. There were no thrombotic events reported.

CONCLUSION

The strategy of targeting higher peak plasma VWF and FVIII:C levels (≥100 IU/dL) at the time of delivery may be effective in reducing the risk of delivery-associated bleeding complications in VWD patients. Yet, the rate of early PPH remains unsatisfactory compared to the non-VWD population.

Von Willebrand Factor (VWF) multiplex activity assay differentiation of type 1 von Willebrand Disease (VWD) and variant VWD

INTRODUCTION

VWD diagnosis is challenging requiring multiple VWF activity tests using many individual assays. We have developed an ELISA-based VWF Multiplex Activity Assay (VWF-MAA) to address this concern; however, the ability of the VWF-MAA to discriminate between type 1 VWD, variant VWD, and normal subjects has not been evaluated.

AIM

To evaluate the VWF-MAA and its ability to differentiate between type 1 VWD, variant VWD and normal subjects in individuals undergoing an initial laboratory evaluation for bleeding.

METHODS

A total of 177 plasma samples from the Zimmerman Program: Comparative Effectiveness in the Diagnosis of VWD were evaluated from 11 centres across the US and Canada. The VWF-MAA was compared to Versiti Blood Research Institute (VBRI) and Local Center (LC) assigned VWD diagnosis.

RESULTS

Overall, 129/177 (72.9%) were correctly assigned as normal (non-VWD), type 1, or variant VWD compared to the VBRI assigned diagnosis. VWF-MAA assigned non-VWD accurately in 29/57 (50.9%) samples, and type 1 VWD accurately in 93/110 (84.6%) samples. Considering LC diagnosis where there was agreement with VWF-MAA and not VBRI diagnosis, type 1 VWD was accurate in 105/110 (95.5%) samples. Bland-Altman analysis demonstrated good correlation between laboratory methods. VWD, types 2A, 2B, 1C VWD were also assigned by the VWF-MAA.

CONCLUSIONS

We demonstrate that the VWF-MAA has utility in differentiating type 1 VWD, variant VWD and normal subjects in individuals undergoing an initial laboratory evaluation for bleeding.

Management of pregnant women who have bleeding disorders

Bleeding disorders, including von Willebrand disease (VWD), hemophilia, other coagulation factor deficiencies, platelet disorders, defects of fibrinolysis, and connective tissue disorders, have both maternal and fetal implications. Successful management of bleeding disorders in pregnant women requires not only an understanding of bleeding disorders but also an understanding of when and how bleeding occurs in pregnancy. Bleeding does not occur during a normal pregnancy with a healthy placenta. Bleeding occurs during pregnancy when there is an interruption of the normal utero-placental interface, during miscarriage, during an ectopic pregnancy, or at the time of placental separation at the conclusion of pregnancy. Although mild platelet defects may be more prevalent, the most commonly diagnosed bleeding disorder among women is VWD. Other bleeding disorders are less common, but hemophilia carriers are unique in that they are at risk of bleeding themselves and of giving birth to an affected male infant. General guidance for maternal management of a woman who is moderately or severely affected includes obtaining coagulation factor levels at a minimum in the third trimester; planning for delivery at a center with hemostasis expertise; and anticipating the need for hemostatic agents. General guidance for fetal management includes pre-pregnancy counseling; the option of preimplantation genetic testing for hemophilia; delivery at a tertiary care center with pediatric hematology and newborn intensive care; consideration of cesarean delivery of a potentially severely affected infant; and avoidance of invasive procedures such as scalp electrodes and operative vaginal delivery in any potentially affected infant.

A case of delayed postoperative bleeding after excision of endometrial polyp using resectoscope in an infertile woman with von Willebrand disease:a case report and literature review

Von Willebrand disease (VWD) is a bleeding disorder caused by a congenital quantitative reduction, deficiency, or qualitative abnormality of the von Willebrand factor (VWF). Here, we report a case of delayed postoperative bleeding in an infertile woman with endometrial polyps complicated by VWD. The patient was a 39-year-old infertile woman with type 2A VWD. At 38 years of age, she was referred to our hospital for infertility and heavy menstrual bleeding. Hysteroscopy revealed a 15-mm polyp lesion in the uterus. The patient was scheduled for transcervical resection (TCR) of the endometrial polyp. Gonadotropin-releasing hormone agonists were preoperatively administered to prevent menstruation. The VWF-containing concentrate was administered for 3 days according to guidelines. The patient was discharged on postoperative day 3 after confirming the absence of uterine bleeding. Uterine bleeding began on postoperative day 6. The patient was readmitted on postoperative day 7 and treated with VWF-containing concentrate for 5 days, after which hemostasis was confirmed. TCR surgery for endometrial lesions is classified as a minor surgery, and guidelines recommend short-term VWF-containing concentrate replacement. However, it should be kept in mind that only short-term VWF-containing concentrate replacement may cause rebleeding postoperatively.

Population-based prevalence and mutational landscape of von Willebrand disease using large-scale genetic databases

Von Willebrand disease (VWD) is a common bleeding disorder caused by mutations in the von Willebrand factor gene (VWF). The true global prevalence of VWD has not been accurately established. We estimated the worldwide and within-population prevalence of inherited VWD by analyzing exome and genome data of 141,456 individuals gathered by the genome Aggregation Database (gnomAD). We also extended our data deepening by mining the main databases containing VWF variants i.e., the Leiden Open Variation Database (LOVD) and the Human Gene Mutation Database (HGMD) with the goal to explore the global mutational spectrum of VWD. A total of 4,313 VWF variants were identified in the gnomAD population, of which 505 were predicted to be pathogenic or already reported to be associated with VWD. Among the 282,912 alleles analyzed, 31,785 were affected by the aforementioned variants. The global prevalence of dominant VWD in 1000 individuals was established to be 74 for type 1, 3 for 2A, 3 for 2B and 6 for 2M. The global prevalences for recessive VWD forms (type 2N and type 3) were 0.31 and 0.7 in 1000 individuals, respectively. This comprehensive analysis provided a global mutational landscape of VWF by means of 927 already reported variants in the HGMD and LOVD datasets and 287 novel pathogenic variants identified in the gnomAD. Our results reveal that there is a considerably higher than expected prevalence of putative disease alleles and variants associated with VWD and suggest that a large number of VWD patients are undiagnosed.

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.

Von Willebrand disease: Gaining a global perspective

INTRODUCTION

Recent guidelines for von Willebrand Disease (VWD) highlighted the challenges in diagnosis and management. Identifying the number of persons with VWD (PwVWD) internationally will help target support to aid diagnosis of PwVWD.

AIM

To examine international registration rates of PwVWD, the influence of income status, geographical region and the age and sex profile. Cumulatively, these data will be used to inform future strategy from the World Federation of Haemophilia (WFH) to address unmet clinical and research needs.

METHODS

Data from the 2018/2019 WFH Annual Global Survey (AGS) were analysed, providing a global perspective on VWD registration.

RESULTS

Registration rates are lowest in South Asia (0.6/million population) and highest in Europe/Central Asia (50.9/million population, 0.005%), but below the expected prevalence rate (0.1%). National economic status impacted VWD registration rates, reflecting variation in access to optimal healthcare infrastructure. Females represented the majority of PwVWD globally, however, in low-income countries (LIC) males predominated. Age profile varied, with markedly higher rates of paediatric registrations in North America, Middle East and North Africa and South Asia. Rates of type 3 VWD registrations were significantly influenced by economic status (81% of VWD diagnoses in LIC), suggesting only the most severe VWD types are diagnosed in resource limited settings.

CONCLUSION

Significant variation in registration rates of PwVWD exist internationally and is influenced by income status and the presence of HTC networks. Improved understanding of registration rates will enable targeting of advocacy to improve awareness, diagnosis and support for PwVWD internationally.

KEY POINTS

Registration rates of People with Von Willebrand Disease (PwVWD) vary internationally and are influenced by national income status Although females represent the majority of PwVWD globally, in low income countries (LIC) males predominated, possibly related to stigma surrounding gynaecological bleeding. Rates of type 3 VWD registration were significantly influenced by economic status (81% of VWD diagnoses in LIC), suggesting only the most severe VWD types are diagnosed in resource limited settings.

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.

Von Willebrand Disease Epidemiology, Burden of Illness and Management: A Systematic Review

Introduction

Although hereditary von Willebrand disease (VWD) is the most common bleeding disorder, its epidemiology is not well understood. A systematic review (PROSPERO CRD42020197674/CRD42021244374) on the epidemiology/burden of illness of VWD was conducted to better understand patients' unmet needs.

Methods

Observational studies (published January 1, 2010 to April 14, 2021) were identified in MEDLINE and Embase databases, using free-text keywords and thesaurus terms for VWD and outcomes of interest. Pragmatic web-based searches of the gray literature, including conference abstracts, were performed, and reference lists of retained publications were manually searched for additional sources. Case reports and clinical trials (phase 1-3) were excluded. Outcomes of interest were incidence, prevalence, mortality, patient characteristics, burden of illness, and therapeutic management/treatments currently used for VWD.

Results

Of the 3095 identified sources, 168 were included in this systematic review. Reported VWD prevalence (22 sources) ranged from 108.9 to 2200 per 100,000 in population-based studies and from 0.3 to 16.5 per 100,000 in referral-based studies. Reported times between first symptom onset and diagnosis (two sources; mean 669 days; median 3 years) highlighted gaps in timely VWD diagnosis. Bleeding events reported in 72-94% of the patients with VWD (all types; 27 sources) were mostly mucocutaneous including epistaxis, menorrhagia, and oral/gum bleeding. Poorer health-related quality of life (three sources) and greater health care resource utilization (three sources) were reported for patients with VWD than in general populations.

Conclusion

Available data suggest that patients with VWD experience high disease burden in terms of bleeding, poor quality of life, and health care resource utilization.

Building the foundation for a community-generated national research blueprint for inherited bleeding disorders: research priorities for mucocutaneous bleeding disorders

BACKGROUND

Excessive or abnormal mucocutaneous bleeding (MCB) may impact all aspects of the physical and psychosocial wellbeing of those who live with it (PWMCB). The evidence base for the optimal diagnosis and management of disorders such as inherited platelet disorders, hereditary hemorrhagic telangiectasia (HHT), hypermobility spectrum disorders (HSD), Ehlers-Danlos syndromes (EDS), and von Willebrand disease (VWD) remains thin with enormous potential for targeted research.

RESEARCH DESIGN AND METHODS

National Hemophilia Foundation and American Thrombosis and Hemostasis Network initiated the development of a National Research Blueprint for Inherited Bleeding Disorders with extensive all-stakeholder consultations to identify the priorities of people with inherited bleeding disorders and those who care for them. They recruited multidisciplinary expert working groups (WG) to distill community-identified priorities into concrete research questions and score their feasibility, impact, and risk.

RESULTS

WG2 detailed 38 high priority research questions concerning the biology of MCB, VWD, inherited qualitative platelet function defects, HDS/EDS, HHT, bleeding disorder of unknown cause, novel therapeutics, and aging.

CONCLUSIONS

Improving our understanding of the basic biology of MCB, large cohort longitudinal natural history studies, collaboration, and creative approaches to novel therapeutics will be important in maximizing the benefit of future research for the entire MCB community.

Prevalence of Bleeding Symptoms in Denmark Using the Patient-administered Bleeding Assessment Tool (self-BAT)

INTRODUCTION

The patient-administered bleeding assessment tool (self-BAT) is a screening tool developed to identify individuals in need of work-up for bleeding disorders. Nonetheless, large studies on self-BAT scores on healthy individuals according to gender and age are lacking.

AIM

Determine cut-offs for abnormal total score of self-BAT and investigate the prevalence of bleeding symptoms in blood donors and individuals representative of the general Danish population.

METHODS

Blood donors, 15,600 children (<18 years) and 18,200 adults from the general Danish population, were invited to complete a Danish version of the self-BAT. To determine cut-offs for abnormal total self-BAT score, findings from healthy young children (0-11 years old), healthy adolescents (12-17 years old), healthy adult women and healthy adult men were used.

RESULTS

Among healthy young children (244 girls, 260 boys), healthy adolescents (58 girls, 83 boys), healthy women (n = 437) and healthy men (n = 278) from the general population, along with healthy blood donors (116 women, 176 men), the 95^th percentile for total score was two for young girls, three for young boys, four for adolescent girls, three for adolescent boys, eight for women and four for men.

CONCLUSION

Our findings indicate that the abnormal total self-BAT score is ≥3 for girls aged 0-11 years old, ≥4 for boys aged 0-11 years old, ≥5 for girls aged 12-17 years old, ≥4 for boys aged 12-17 years old, ≥9 for women and ≥5 for men. To establish the accuracy of these cut-offs for diagnosing bleeding disorders, further studies are needed.

A need to increase von Willebrand disease awareness: vwdtest.com - A global initiative to help address this gap

Von Willebrand disease (VWD) is an inherited bleeding disorder caused by quantitative or qualitative deficiencies in von Willebrand factor (VWF). People with VWD may experience excessive, recurrent or prolonged bleeding, particularly during menstruation, childbirth, surgery or following trauma. However, many VWD patients are undiagnosed, and therefore inadequately treated. Reasons for the underdiagnosis of VWD include its relatively mild symptoms, complex diagnosis, lack of awareness among non-specialist healthcare providers and the general population, and a lack of prioritisation of disorders disproportionately affecting females. The vwdtest.com platform was launched as part of a global initiative to raise awareness and improve diagnosis of VWD. Besides providing VWD-specific educational resources, the website includes an online bleeding self-assessment tool and offers diagnostic support for individuals, and their providers, who have a score suggestive of a bleeding disorder. vwdtest.com helps to address these unmet needs, especially in regions with limited access to educational and diagnostic resources.

Clinical, economic, and health-related quality of life burden associated with von Willebrand disease in adults and children: Systematic and targeted literature reviews

INTRODUCTION

Debilitating clinical complications in von Willebrand disease (VWD) can affect health-related quality of life (HRQoL), increase healthcare costs and cause long-lasting consequences. However, the magnitude of these burdens needs to be more fully explored.

AIM

To estimate the prevalence and burden of clinical complications, the impact on HRQoL and the economic burden associated with VWD.

METHODS

Embase^® , MEDLINE^® , the Cochrane Library and conference proceedings were searched for studies on VWD evaluating clinical complications, HRQoL and cost and resource use.

RESULTS

Among 16 studies assessing clinical complications in VWD, the most prevalent bleeding symptoms were menorrhagia (2%-95% [n = 7 studies]), epistaxis (12%-80% [n = 6]) and easy bruising (46%-65% [n = 2]). Among 17 studies evaluating HRQoL, the most common assessment scales were the generic SF-36 (n = 8 studies) and the EQ-5D (n = 2). Bleeding symptoms were associated with reduced QoL in six of seven studies, and of six studies evaluating treatment impact, four reported improvements in one or more HRQoL components. Among 25 studies on cost and resource use, key observations included higher post-surgery healthcare costs in VWD versus non-VWD patients (n = 1 study) and higher costs and resource use in VWD patients with bleeding complications versus those without (n = 1).

CONCLUSION

Although limited, available evidence suggests that VWD patients experience a high burden of clinical complications, reduced QoL and high healthcare costs. Haemarthrosis is more common in severe VWD than is often assumed, and bleeds (including haemarthrosis) can reduce QoL. Research efforts to improve QoL and other outcomes should be prioritized.

Low von Willebrand Disease: A Bleeding Disorder of Unknown Cause?

von Willebrand disease (VWD) represents the most common inherited bleeding disorder. The majority of VWD cases are characterized by partial quantitative reductions in plasma von Willebrand factor (VWF) levels. Management of patients with mild to moderate VWF reductions in the range of 30 to 50 IU/dL poses a common clinical challenge. Some of these low VWF patients present with significant bleeding problems. In particular, heavy menstrual bleeding and postpartum hemorrhage can cause significant morbidity. Conversely, however, many individuals with mild plasma VWF:Ag reductions do not have any bleeding sequelae. In contrast to type 1 VWD, most patients with low VWF do not have detectable pathogenic VWF sequence variants, and bleeding phenotype correlates poorly with residual VWF levels. These observations suggest that low VWF is a complex disorder caused by variants in other genes beyond VWF. With respect to low VWF pathobiology, recent studies have shown that reduced VWF biosynthesis within endothelial cells likely plays a key role. However, pathological enhanced VWF clearance from plasma has also been described in approximately 20% of low VWF cases. For low VWF patients who require hemostatic treatment prior to elective procedures, tranexamic acid and desmopressin have both been shown to be efficacious. In this article, we review the current state of the art regarding low VWF. In addition, we consider how low VWF represents an entity that appears to fall between type 1 VWD on the one hand and bleeding disorders of unknown cause on the other.

The diagnosis, natural history, and management of von Willebrand disease in women in the age of guidelines

INTRODUCTION

Women and girls with bleeding disorders face multiple bleeding challenges throughout their life. The most significant morbidity and mortality are due to heavy menstrual bleeding and postpartum hemorrhage in their reproductive years. The ASH/ISTH/NHF/WFH 2021 guidelines on diagnosing and managing von Willebrand disease (VWD) provide several new updates.

AREAS COVERED

Women with VWD have a higher prevalence of heavy menstrual bleeding. The subpopulation of adolescents is particularly vulnerable, as the diagnosis is often delayed with increased comorbidity of iron deficiency anemia and associated symptoms. A detailed review is done on the prevalence of bleeding-related complications, especially heavy menstrual bleeding (HMB) and post-partum hemorrhage (PPH). The management strategies are also reviewed in detail, with a specific focus on the target factor levels and the use of antifibrinolytics.

EXPERT OPINION

The 2021 ASH/ISTH/NHF/WFH diagnostic and management recommendations are reviewed with a specific focus on hormonal methods of HMB management and antifibrinolytics in this situation. The reviewed topics include neuraxial anesthesia, factor cutoff, and tranexamic acid use in the postpartum period.

Patients with von Willebrand disease in China: Results of an online survey

INTRODUCTION

Little is known about the clinical characteristics of von Willebrand disease (VWD) patients in China, the impact of Covid-19 on them and their genetic mutation.

AIM

To describe the clinical characteristics of a group of VWD patients in China, the impact of Covid-19 on them and their genetic mutation.

METHODS

An online survey using a self-designed questionnaire was conducted among patients within a WeChat group of VWD patients in China. Data were analysed using t-test, the Chi-square test, Fisher's exact test and rank sum test.

RESULTS

Data from a total of 96 patients were collected. Several important findings are yielded. Above all, type 3 patients accounted for over half of the surveyed patients. Secondly, a surprising rate (>40%) of patients had experience of being misdiagnosed. Thirdly, treatment regimens were dominated by cryoprecipitate, blood-derived FVIII and plasma, and only a small percentage of patients received prophylaxis. Fourthly, we identified 17 new von Willebrand factor (VWF) mutant genes which merit further investigation. Additionally, Covid-19 was found to pose some challenges for the patients.

CONCLUSION

In China, the high rates of type 3 patients and misdiagnosis suggest that most of the VWD patients may never be diagnosed in China. When it comes to diagnosis and treatment, there is a large gap between developing countries like China and developed countries.

Special considerations in GI bleeding in VWD patients

Gastrointestinal (GI) bleeding is an important cause of morbidity and mortality in von Willebrand disease (VWD). It has been noted that GI bleeding caused by angiodysplasia is overrepresented in VWD patients compared to other causes. The bleeding from angiodysplasia is notoriously difficult to treat; recurrences and rebleeds are common. A growing body of basic science evidence demonstrates that von Willebrand factor negatively regulates angiogenesis through multiple pathways. VWD is clinically highly associated with angiodysplasia. The predisposition to angiodysplasia likely accounts for many of the clinical difficulties related to managing GI bleeding in VWD patients. Diagnosis and treatment are challenging with the current tools available, and much further research is needed to further optimize care for these patients with regard to acute treatment, prophylaxis, and adjunctive therapies. In this review we provide an overview of the available literature on GI bleeding in VWD and explore the molecular underpinnings of angiodysplasia-related GI bleeding. Considerations for diagnostic effectiveness are discussed, as well as the natural history and recurrence of these lesions and which therapeutic options are available for acute and prophylactic management.

What have we learned about the patient's experience of von Willebrand disease? A focus on women

Von Willebrand disease (VWD), the most common inherited bleeding disorder (IBD), disproportionately affects females, given the hemostatic challenges they may encounter throughout their lifetimes. Despite this, research about VWD remains grossly underrepresented, particularly compared to hemophilia, which is historically diagnosed in males. Structural sexism, stigmatization of menstrual bleeding, delayed diagnosis, and a lack of timely access to care result in an increased frequency of bleeding events, iron deficiency, iron deficiency anemia, and a decreased quality of life. However, we are only beginning to recognize and acknowledge the magnitude of the burden of this disease. With an increasing number of studies documenting the experiences of women with IBDs and recent international guidelines suggesting changes to optimal management, a paradigm shift in recognition and treatment is taking place. Here, we present a fictional patient case to illustrate one woman's history of bleeding. We review the evidence describing the impact of VWD on quality of life, normalization of vaginal bleeding, diagnostic delays, and the importance of access to multidisciplinary care. Furthermore, we discuss considerations around reproductive decision-making and the intergenerational nature of bleeding, which often renders patients as caregivers. Through incorporating the patient perspective, we argue for an equitable and compassionate path to overcome decades of silence, misrecognition, and dismissal. This path moves toward destigmatization, open dialogue, and timely access to specialized care.

Safety and Feasibility of Catheter Ablation Procedures in Patients with Bleeding Disorders

Aims/Objectives: Patients with bleeding disorders are a rare and complex population in catheter ablation (CA) procedures. The most common types of bleeding disorders are von Willebrand disease (VWD) and hemophilia A (HA). Patients with VWD or HA tend to have a higher risk of bleeding complications compared to other patients. There is a lack of data concerning peri- and postinterventional coagulation treatment. We sought to assess the optimal management of patients with VWD and HA referred for catheter ablation procedures. Methods and Results: In this study, we analyzed patients with VWD or HA undergoing CA procedures at two centers in Germany and Switzerland between 2016 and 2021. Clotting factors were administered in conjunction with hemostaseological recommendations. CA was performed as per the institutional standard. During the procedure, unfractionated heparin (UFH) was given intravenously with respect to the activated clotting time (ACT). Primary endpoints included the feasibility of the procedure, bleeding complications, and thromboembolic events during the procedure. Secondary endpoints included bleeding complications and thromboembolic events up to one year after catheter ablation. A total of seven patients (three VWD Type I, one VWD Type IIa, three HA) underwent 10 catheter ablation procedures (pulmonary vein isolation (PVI): two × radiofrequency (RF), one × laser balloon (LB), one × cryoballoon (CB); PVI + cavotricuspid isthmus (CTI): one × RF; PVI + left atrial appendage isolation (LAAI): one × RF; Premature ventricular contraction (PVC): three × RF; Atrioventricular nodal reentrant tachycardia (AVNRT): one × RF). VWD patients received 2000−3000 IE Wilate i.v. 30 to 45 min prior to ablation. Patients with HA received 2000−3000 IE factor VIII before the procedure. All patients undergoing PVI received UFH (cumulative dose 9000−18,000 IE) with a target ACT of >300 s. All patients after PVI were started on oral anticoagulation (OAC) 12 h after ablation. Two patients received aspirin (acetylsalicylic acid; ASA) for 4 weeks after the ablation of left-sided PVCs. No anticoagulation was prescribed after slow pathway modulation in a case with AVNRT. No bleeding complications or thromboembolic events were reported. During a follow-up of one year, one case of gastrointestinal bleeding occurred following OAC withdrawal after LAA occlusion. Conclusions: After the substitution of clotting factors, catheter ablation in patients with VWD and HA seems to be safe and feasible.

Longitudinal bleeding assessment in von Willebrand disease utilizing an interim bleeding score

BACKGROUND

Assessment of bleeding phenotype is critically important in the diagnosis of von Willebrand disease (VWD). Despite advances in bleeding assessment tools (BATs), standardized tools to evaluate bleeding following diagnosis (interim bleeding) are lacking.

OBJECTIVES

We assessed the clinical utility of an interim bleeding protocol in a multicenter, international study involving patients with VWD.

METHODS

The enrolment ISTH BAT formed the original bleeding score (0 BS). At follow-up, the International Society on Thrombosis and Haemostasis BAT was repeated but included only interval bleeding (Interim BS, 1 BS). Both scores were annualized (0 BS/yr, 1 BS/yr). BS were analyzed by VWD subtype, plasma VWF level, sex, and age.

RESULTS

Interim BS discriminated by subtype, with significantly increased 0 BS and 1 BS in patients with type 3 VWD. In patients with type 1 VWD, a positive or negative 0 BS did not predict future bleeding, with similar 1 BS/yr (median 1.0 vs. 0.7, p = .2). Despite significantly higher 0 BS in females with type 1 VWD than males (median 7 vs. 5, p = .0012), 1 BS were not significantly different (median 4 vs. 4, p = .16). While 0 BS were lower in children than adults with type 1 VWD, interim BS were similar (median 5 vs. 3, p = .5; 1BS/yr, median 1 vs. 0.8, p = .7). Interestingly, in those with plasma von Willebrand factor:ristocetin cofactor levels >50 IU/dl, interim BS rates were similar to those 30-50 IU/dl (1 BS/yr 0.8 vs. 1.3, p = .5).

CONCLUSION

This study provides both a new approach to longitudinal bleeding assessment and insights into the evolution of bleeding in VWD.

Recombinant von Willebrand factor prophylaxis in patients with severe von Willebrand disease: phase 3 study results

International guidelines conditionally recommend long-term prophylaxis in patients with von Willebrand disease (VWD) and severe and frequent bleeding. As recombinant von Willebrand factor (rVWF; vonicog alfa) may reduce the frequency of treated spontaneous bleeding events (BEs), we investigated the efficacy and safety of rVWF prophylaxis in adults with severe VWD. Patients with BEs requiring VWF therapy in the past year (on-demand VWF therapy [prior on-demand group] or plasma-derived VWF prophylaxis [pdVWF; switch group]) were enrolled in a prospective, open-label, nonrandomized, phase 3 study. The planned duration of rVWF prophylaxis was 12 months; starting rVWF dose was 50 ± 10 VWF: ristocetin cofactor (VWF:RCo) IU/kg twice weekly (prior on-demand group) or based on prior pdVWF weekly dose/dosing frequency (switch group). The primary endpoint was annualized bleeding rate (ABR) of treated spontaneous BEs (sABR) during rVWF prophylaxis. Over the 12-month study period, treated sABR decreased by 91.5% on-study vs historical sABR in 13 patients in the prior on-demand group, and by 45.0% in 10 patients in the switch group (model-based analysis ratio, 0.085; 95% confidence interval [CI], 0.021-0.346 and 0.550; 95% CI, 0.086-3.523, respectively). No treated spontaneous BEs were recorded in 84.6% (11/13) and 70.0% (7/10) of patients, respectively. The safety profile of rVWF was consistent with the previously established profile, with no new adverse drug reactions identified. Findings suggest that rVWF prophylaxis can reduce treated spontaneous BEs in patients previously receiving on-demand VWF therapy and maintains at least the same level of hemostatic control in patients who switch from prophylaxis with pdVWF to rVWF, with a favorable safety profile. This trial was registered at www.clinicaltrials.gov (#NCT02973087) and www.clinicaltrialsregister.eu (#EudraCT 2016-001478-14).

Interaction of von Willebrand factor with blood cells in flow models: a systematic review

The presence of blood flow influences the interaction between von Willebrand factor (VWF) and blood cells, affecting characteristics of forming blood clots. The interactions between coagulation and inflammation have mainly been studied in thrombosis models, but it remains unclear whether these interactions might also play a role in reduced bleeding in patients with bleeding disorders. In this systematic review, we provide an overview of the literature investigating the interactions between VWF and blood cells in flow models. For article selection, a systematic search was performed in Embase, Medline-Ovid, Cochrane Library, Web of Science databases, and Google Scholar. After selection, 24 articles were included. These articles describe direct or platelet-dependent interactions between VWF and neutrophils, monocytes, erythrocytes, or lymphocytes under different flow conditions. Almost all the described interactions required the presence of activated platelets. Only erythrocytes, monocytes, and natural killer cells were capable of directly binding the VWF multimers. Overall, interactions between VWF and blood cells mainly occurred in the presence of platelets. Because of the large variation in study design and used flow rates, further research is necessary to compare the results between studies and draw firm conclusions on when and under what conditions these interactions can occur. After our findings, many questions remained unanswered. This review might provide a starting point for future research. Extended knowledge on the influence of blood flow on VWF and blood cell interactions can contribute to improved understanding of the variation in bleeding in patients with bleeding disorders.

Effectiveness of long-term prophylaxis using pdFVIII/VWF concentrate in patients with inherited von Willebrand disease

Background

Patients with symptomatic von Willebrand disease (VWD) should be offered long‐term prophylaxis (LTP) to prevent recurrent bleedings. Our objective was to evaluate the effectiveness and safety of Voncento®, a plasma‐derived FVIII/VWF concentrate (ratio 1:2.4), administrated in LTP.

Methods

We included patients from the OPALE study (May 2016 to April 2021), a French multicenter observational study following patients with inherited VWD, who received a Voncento® LTP during the study period.

Results

Among the 130 OPALE‐study patients, 23 patients (12 women) received a LTP and were therefore included. The median (range) age was 16 (1–85) years; 16 patients were type 3, 1 was type 2A, 6 were type 2B. Before inclusion, 19 (83%) were under LTP and 4 (17%) received on‐demand (OD) treatment. The indications for initiating prophylaxis in the overall population were joint bleeding (43%), ear, nose, and throat (ENT) bleeding including epistaxis or oral bleeding (39%), and recurrent muscle hematoma (22%). The medians (ranges) dose of Voncento® per infusion, frequency, and weekly dose were 45 (33–109) IU/kg, 2 infusions per week, and 96 (44–222) IU/kg/week, respectively. The median (range) annualized bleeding rate (ABR) was 0.8, 0.7 (0–3.5), and 0 (0–2.3) for type 2A, 2B, 3 patients, respectively. There was no difference regarding to the dose, frequency of infusion, or in terms of ABR in 9/19 patients who replaced previous concentrates with Voncento®. During the study period, no adverse event was reported.

Conclusion

These results suggest that Voncento® is effective to prevent recurrent bleedings in patients symptomatic VWD.

Laboratory Assays of VWF Activity and Use of Desmopressin Trials in the Diagnosis of VWD: A Systematic Review and Meta-Analysis

The findings of these reviews support VWF multimer analysis or VWF:CB/VWF:Ag to diagnose type 2 VWD.

The reviews confirm that desmopressin trial is the test of choice to confirm increased VWF clearance in patients with suspected VWD type 1C.

von Willebrand Disease (VWD) is associated with significant morbidity because of excessive bleeding. Early diagnosis and treatment are important to prevent and treat these symptoms. We systematically reviewed the accuracy of any von Willebrand factor (VWF) activity assay in the diagnosis and classification of patients for VWD. We searched Cochrane Central, MEDLINE, and EMBASE for eligible studies. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 and the certainty of evidence using the GRADE framework. We pooled estimates of sensitivity and specificity. The review included 77 studies that evaluated the use of newer tests of VWF platelet binding activity (VWF:GPIbR, VWF:GPIbM) and VWF:RCo for the diagnosis of VWD (13 studies), VWF propeptide to VWF:Ag ratio, and desmopressin trial for the diagnosis of type 1C VWD (5 studies), VWF multimer analysis and VWF:CB/VWF:Ag ratio for the classification of type 2 VWD (11 studies), genetic testing and ristocetin-induced platelet aggregation to diagnose type 2B VWD (14 studies), genetic testing and FVIII:VWF binding to diagnose type 2N VWD (17 studies). Based on available diagnostic test accuracy, there appear to be comparable test accuracy results between newer tests of platelet binding activity of VWF function and VWF:RCo. The findings of these reviews support VWF multimer analysis or VWF:CB/VWF:Ag to diagnose type 2 VWD. The desmopressin trial test with 1- and 4-hour postinfusion blood work is the test of choice to confirm increased VWF clearance in patients with suspected VWD type 1C. Additionally, genetic testing is most useful in diagnosing type 2B VWD and has a role in the diagnostic algorithm of suspected type 2N VWD.

Clinical Efficacy and Safety of Fanhdi®, a Plasma-Derived VWF/Factor VIII Concentrate, in von Willebrand Disease in Spain: A Retrospective Study

Objective

To evaluate the efficacy and safety of a plasma-derived factor VIII concentrate containing von Willebrand Factor (pdVWF/FVIII) in standard clinical practice in von Willebrand Disease (VWD) patients.

Methods

A retrospective, multicentric, observational study of VWD patients treated with Fanhdi^®, a pdVWF/FVIII concentrate, from January 2011 to December 2017 was conducted at 14 centers in Spain. Efficacy and safety were evaluated for acute bleeding episodes, for prevention of bleeding in surgeries, and for secondary long-term prophylaxis.

Results

Seventy-two eligible patients, type 1, 2, 3 VWD (25%/38.9%/36.1%) were treated for spontaneous and traumatic bleeding (140 episodes, n = 41 patients), to prevent surgical bleeding (69 episodes, n = 43 patients); and for secondary long-term prophylaxis (18 programs, n = 13 patients). Replacement therapy with pdVWF/FVIII showed an excellent to good clinical efficacy in 96.7% of the bleeding episodes, 100% during surgical procedures and 100% during prophylaxis. No adverse events (AEs), nor serious AEs related to the product were observed.

Conclusions

Fanhdi^® was effective, safe and well tolerated in the management of bleeding episodes, the prevention of bleeding during surgeries, and for secondary long-term prophylaxis in VWD patients.

von Willebrand factor levels in the diagnosis of von Willebrand disease: a systematic review and meta-analysis

von Willebrand disease (VWD) is associated with significant morbidity as a result of excessive mucocutaneous bleeding. Early diagnosis and treatment are important to prevent and treat these symptoms. We systematically reviewed the accuracy of diagnostic tests using different cutoff values of von Willebrand factor antigen (VWF:Ag) and platelet-dependent von Willebrand factor (VWF) activity assays in the diagnosis of VWD. We searched Cochrane Central Register for Controlled Trials, MEDLINE, and Embase databases for eligible studies. We pooled estimates of sensitivity and specificity and reported patient-important outcomes when relevant. This review included 21 studies that evaluated VWD diagnosis. The results showed low certainty in the evidence for a net health benefit from reconsidering the diagnosis of VWD vs removing the disease diagnosis in patients with VWF levels that have normalized with age. For the diagnosis of type 1 VWD, VWF sequence variants were detected in 75% to 82% of patients with VWF:Ag < 0.30 IU/mL and in 44% to 60% of patients with VWF:Ag between 0.30 and 0.50 IU/mL. A sensitivity of 0.90 (95% confidence interval [CI], 0.83-0.94) and a specificity of 0.91 (95% CI, 0.76-0.97) were observed for a platelet-dependent VWF activity/VWF:Ag ratio < 0.7 in detecting type 2 VWD (moderate certainty in the test accuracy results). VWF:Ag and platelet-dependent activity are continuous variables that are associated with an increase in bleeding risk with decreasing levels. This systematic review shows that using a VWF activity/VWF:Ag ratio < 0.7 vs lower cutoff levels in patients with an abnormal initial VWD screen is more accurate for the diagnosis of type 2 VWD.

The Cost of Von Willebrand Disease in Europe: The CVESS Study

Background

Von Willebrand disease (VWD) is one of the most common inherited bleeding disorders, imposing a substantial health impact and financial burden. The Cost of von Willebrand disease in Europe: A Socioeconomic Study (CVESS) characterises the socio-economic cost of VWD across Germany, Spain, Italy, France, and the UK.

Methods

A retrospective, cross-sectional design captured 12 months of patient disease management, collected from August-December 2018, for 974 patients. This enabled estimation of direct medical, direct non-medical and indirect costs, utilising prevalence estimates to extrapolate to population level.

Results

Total annual direct medical cost (including/excluding von Willebrand factor [VWF]) across all countries was the highest cost (€2 845 510 345/€444 446 023), followed by indirect costs (€367 330 271) and direct non-medical costs (€60 223 234). Differences were seen between countries: the UK had the highest direct medical costs excluding VWF (€159 791 064), Italy the highest direct-non medical (€26 564 496), and Germany the highest indirect cost burden (€197 036 052). Total direct medical costs per adult patient increased across VWD types with Type 1 having the lowest cost (€23 287) and Type 3 having the highest cost (€133 518).

Conclusion

A substantial financial burden arises from the prevalence of VWD for the European healthcare systems considered.

The lived experience of women with a bleeding disorder: A systematic review

BACKGROUND

Research studies have described the morbidity associated with inherited bleeding disorders such as hemophilia and von Willebrand disease in women, but their effect on daily living has long been underrecognized. This systematic review sought to document the lived experience of women with a bleeding disorder by assessing research findings on quality of health care, socioeconomic factors, and mental health.

METHODS

A systematic search was carried out in Web of Science, the Cumulative Index to Nursing and Allied Health Literature, and PubMed on July 31, 2020. References were hand searched. Abstracts of the 2019 and 2020 congresses on bleeding disorders were hand searched. Key journals were screened for relevant studies published after the search date until the analysis was completed on December 7, 2020.

RESULTS

Of 635 potentially eligible publications, 27 published since 1998 were selected for review. Most studies were of moderate to high quality but meta-analysis of quantitative studies was not possible due to difference in outcomes and assessment.Women with a bleeding disorder experience obstacles to accessing care, difficulties living with their disorder, interference with schooling and work, and poor mental health. Diagnostic delay and lack of recognition of symptoms mean treatment and support may not be available. Where comparisons with controls were made, women's negative experiences were greater than those of men.

CONCLUSIONS

Women with bleeding disorders experience major negative impacts of their disorders on daily life and mental well-being. Many of the challenges identified in earlier research are evident in more recent studies.

Bleeding assessment tools in the diagnosis of VWD in adults and children: a systematic review and meta-analysis of test accuracy

Von Willebrand disease (VWD) can be associated with significant morbidity. Patients with VWD can experience bruising, mucocutaneous bleeding, and bleeding after dental and surgical procedures. Early diagnosis and treatment are important to minimize the risk of these complications. Several bleeding assessment tools (BATs) have been used to quantify bleeding symptoms as a screening tool for VWD. We systematically reviewed diagnostic test accuracy results of BATs to screen patients for VWD. We searched Cochrane Central, MEDLINE, and EMBASE for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. Two investigators screened and abstracted data. Risk of bias was assessed using the revised tool for the quality assessment of diagnostic accuracy studies and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework. We pooled estimates of sensitivity and specificity. The review included 7 cohort studies that evaluated the use of BATs to screen adult and pediatric patients for VWD. The pooled estimates for sensitivity and specificity were 75% (95% confidence interval, 66-83) and 54% (29-77), respectively. Certainty of evidence varied from moderate to high. This systematic review provides accuracy estimates for validated BATs as a screening modality for VWD. A BAT is a useful initial screening test to determine who needs specific blood testing. The pretest probability of VWD (often determined by the clinical setting/patient population), along with sensitivity and specificity estimates, will influence patient management.

Unraveling the molecular basis underlying nine putative splice site variants of von Willebrand factor

Approximately 10% of von Willebrand factor (VWF) gene variants are suspected to disrupt messenger RNA (mRNA) processing, the number of which might be underestimated due to the lack of transcript assays. In the present study, we provided a detailed strategy to evaluate the effects of nine putative splice site variants (PSSVs) of VWF on mRNA processing as well as protein properties and establish their genotype-phenotype relationships. Eight of nine PSSVs affected VWF splicing: c.322A>T, c.1534-13_1551delinsCA, and c.8116-2del caused exon skipping; c.221-2A>C, c.323+1G>T, and c.2547-13T>A resulted in the activation of cryptic splice sites; c.2684A>G led to exon skipping and activation of a cryptic splice site; c.2968-14A>G created a new splice site. The remaining c.5171-9del was likely benign. The efficiency of nonsense-mediated mRNA decay (NMD) was much higher in platelets compared to leukocytes, impairing the identification of aberrant transcripts in 4 of 8 PSSVs. The nonsense variant c.322A>T partially impaired mRNA processing, leaking a small amount of correct transcripts with c.322T (p.Arg108*), while the missense variant c.2684A>G totally disrupted normal splicing of VWF, rather than produced mutant protein with the substitution of Gln895Arg. The results of this study would certainly add novel insights into the molecular events behind von Willebrand disease.