ASH ISTH NHF WFH 2021 guidelines on the diagnosis of von Willebrand disease

Cost-effectiveness and cost-utility analysis of Haemate-P versus other von Willebrand disease treatments in Spain

OBJECTIVE

von Willebrand Disease (vWD) is the most common congenital bleeding disorder, with an estimated prevalence in Spain of 0.01%. The aim was to assess the cost-utility of Haemate-P compared with present alternatives in the treatment of vWD in Spain.

METHODS

A Markov model was developed in Microsoft Excel to estimate the cost-effectiveness of various treatments for vWD over a lifetime horizon. Transition probabilities among health states were based on age and number of bleeding events. Treatment strategies compared included Haemate-P, Fanhdi, and Wilate in long-term prophylaxis (LTP) or on-demand treatment (ODT). Costs and quality-of-life were measured based on patient age, treatment, and number of bleeding events incurred. Both costs and utilities were discounted at 3%. One-way and probabilistic sensitivity analyses were performed.

RESULTS

When comparing LTP regimens, Haemate-P was less costly and numerically more effective than both Fanhdi (incremental costs = -€1,313,845; incremental quality-adjusted life-years [QALY] = 0.13) and Wilate (incremental costs = -€2,233,940; incremental QALY = 0.29). For ODT, Haemate-P was assumed to have equal effectiveness as Fanhdi and Wilate but reduced the costs by €696,857 and €1,145,780, respectively. Haemate-P prophylaxis was more effective and less costly compared with Haemate-P on-demand in the base case (incremental costs = -€633,317; incremental QALY = 0.90). Results were generally robust to sensitivity analyses.

CONCLUSIONS

In patients with severe vWD experiencing a high bleed rate, Haemate-P prophylaxis is a less costly and potentially more effective treatment strategy and Haemate-P is cost-saving among on-demand strategies.

Loss of von Willebrand factor large multimers in patients undergoing hemodialysis: A single-center, retrospective study

INTRODUCTION

Von Willebrand factor (VWF) is produced by vascular endothelial cells as large multimers and is cleaved by ADAMTS13 into an appropriate size in a shear stress-dependent manner. Excessive shear stress enhances VWF cleavage, leading to a hemorrhagic disease known as acquired von Willebrand syndrome. No clear reports on the prevalence of the loss of VWF large multimers in patients receiving hemodialysis are currently available. Therefore, this study investigated the prevalence of the loss of VWF large multimers in patients undergoing hemodialysis.

METHODS

This single-center, retrospective study involved 90 patients undergoing hemodialysis and 32 healthy participants as controls. VWF antigen levels (VWF:Ag), VWF activity (VWF:RCo), and ADAMTS13 activity were measured. VWF multimer analysis was performed by modified western blotting with an agarose gel electrophoresis, followed by densitometric evaluation of band intensities to calculate the VWF large multimer index (VWF-LMI). A VWF-LMI <80 % was defined as the loss of VWF large multimers, and the prevalence of the loss of VWF large multimers was calculated.

RESULTS

VWF:Ag and VWF:RCo levels in patients undergoing hemodialysis were significantly higher than those in healthy individuals (p < 0.01 both) and were negatively correlated with ADAMTS13 activity (p < 0.01, R = -0.353 and p < 0.01, R = -0.392, respectively). A VWF-LMI <80 % was present in 24 of 90 patients.

CONCLUSIONS

The loss of VWF large multimers was identified in 26.7 % of patients receiving hemodialysis. However, the prevalence of the loss of VWF multimers in these patients may be underestimated, as their relatively high VWF activity makes significant bleeding manifestations less likely.

A rare case of type 2A von Willebrand disease with compound heterozygous mutation

von Willebrand disease (VWD) is defined by a quantitative or qualitative deficiency of von Willebrand factor, which impairs platelet adhesion and aggregation. Here we describe a rare case of type 2A VWD with compound heterozygous mutation. A 27-year-old girl presented with oral bleeding for two days after dental surgery. A systemic physical examination turned up unremarkable. Type 2 von Willebrand disease was confirmed by laboratory tests. Further genetic investigation revealed the existence of compound mutations of VWF (von Willebrand factor) gene, inherited separately from her parents. Interestingly, her mother presented decreased VWF antigen and activity, but that was not found in her father.

Glanzmann thrombasthenia: a multi-center study of demographics, clinical spectrum, and treatment efficacy

Glanzmann thrombasthenia (GT) is a rare inherited bleeding disorder caused by quantitative or qualitative defects of platelet integrin GPIIb/IIIa (CD41 and CD61). This study intended to describe the demographics, clinical features, and treatment response of GT patients in several hematology centers in Egypt. A cross-sectional multi-center study involved 87 children (<18 years old) diagnosed with GT. Clinical data were recorded as bleeding manifestations, response to treatment modalities, and laboratory results. The study included eighty-seven children (61 females and 26 males) with a median age of 8 years. Sixty-one children (55.2%) were born to parents who were consanguineous. The median age at presentation was 3 years (birth-14 years). The most frequent initial presenting symptom was epistaxis (39.1%), followed by cutaneous bleeding (29.9%), gastrointestinal bleeding (23%), heavy menstrual bleeding (19.5%), bleeding per gum (10.3%), and post-circumcision bleeding (5.7%), while one patient initially presented with intracranial hemorrhage (1.1%). These also constituted common bleeding sites. Eighty children (92%) received treatment. Platelet transfusions were given to 65 patients, with a response rate of 73.8%, and recombinant factor VII concentrates were given to 71 patients, with a response rate of 90.1%. Type I GT represented most of our patients (79.3%), followed by type III (11.5%) and type II (9.2%). No significant correlation was found between CD41/CD61 expression and other parameters as the patient's age, bleeding frequency, and treatment response. There was no evident difference between the three forms of GT regarding clinical characteristics such as bleeding severity or response to treatment. What is known: • Glanzmann thrombasthenia is the most common inherited platelet function abnormality. • Treatment is based on general supportive measures, platelet transfusion and recombinant factor VIIa. What is new: • Glanzmann thrombasthenia is an underestimated disorder, with a significant delay in diagnosis. • Although it has three types, there is no significant variation in bleeding phenotype between them.

DDAVP response and its determinants in bleeding disorders: a systematic review and meta-analysis

ABSTRACT

Desmopressin (1-desamino-8-d-arginine vasopressin [DDAVP]) can be used to prevent or stop bleeding. However, large interindividual variability is observed in DDAVP response and determinants are largely unknown. In this systematic review and meta-analysis, we aimed to identify the response to DDAVP and the factors that determine DDAVP response in patients. We included studies with patients with any bleeding disorder receiving DDAVP. First and second screening round and risk of bias assessment were performed by independent reviewers. The main outcome was proportion of patients with complete (factor level >50 U/dL) or partial (30-50 U/dL) response to DDAVP. Determinants of response including disease type, age, sex, von Willebrand factor (VWF) and factor VIII (FVIII) mutations, and baseline factor levels were investigated. In total, 591 articles were found and 103 were included. Of these, 71 articles (1772 patients) were suitable for the study's definition of response. Meta-analysis showed a pooled response proportion of 0.71 (0.64; 0.78) and a significant difference in response between disease subtypes. For hemophilia A, baseline FVIII activity (FVIII:C) was a borderline significant determinant of response. In patients with von Willebrand disease (VWD) type 1, VWF antigen (VWF:Ag), VWF activity, and FVIII:C were significant determinants. A large variation in response was observed for specific mutations in VWF and FVIII. Response to DDAVP varied between disease subtypes and was largely determined by the baseline levels of FVIII:C for hemophilia A and VWF:Ag for VWD. Our findings highlight the significant differences in response and emphasize the need for a standardized response definition and further research into response mechanisms.

Genomic testing for bleeding disorders (GT4BD): protocol for a randomised controlled trial evaluating the introduction of whole genome sequencing early in the diagnostic pathway for patients with inherited bleeding disorders as compared with standard of care

INTRODUCTION

The current diagnostic pathway for patients with a suspected inherited bleeding disorder is long, costly, resource intensive, emotionally draining for patients and often futile, as half of patients will remain without a diagnosis and be labelled 'bleeding disorder of unknown cause'. Advances in understanding the genetic basis of the inherited bleeding disorders, coupled with both increasing infrastructure for genetic/genomic testing and decreasing costs, have increased the feasibility of introducing genomic testing into the clinical diagnostic pathway as a potential solution to improve the care of these patients. Yet, there remain evidence gaps on the optimal integration of genomic analysis into the diagnostic pathway.

METHODS AND ANALYSIS

Using a multicentre randomised-controlled trial design, we will evaluate an early genomic testing strategy for the diagnosis of newly referred patients with a suspected inherited bleeding disorder. Eligible participants will be randomised to early genomic testing diagnostic pathway (intervention) or standard diagnostic pathway (control) and will be followed for a 12-month period. Patients in the control group who remain undiagnosed at study end will be offered identical early genomic testing to ensure equitable access to the intervention. The study will follow a parallel fixed design with waitlist control group and a 1:1 allocation ratio. The study will be conducted at three tertiary care centres in Ontario, Canada, with a target sample size of 212 participants. Clinical utility will be evaluated via the primary outcome of diagnostic yield, as well as the secondary outcome of time to diagnosis. Additional secondary outcomes will allow for assessment of patient impact via health-related quality of life and patient burden measures, as well as evaluation of economic impact through a cost-effectiveness analysis and budget impact analysis.

ETHICS AND DISSEMINATION

This investigator-initiated study was approved by the Queen's University Health Sciences and Affiliated Teaching Hospitals Research Ethics Board through Clinical Trials Ontario (CTO-4909). Participant informed consent/assent is required. Findings will be disseminated through academic publications.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT06736158.

A fully humanized von Willebrand disease type 1 mouse model as unique platform to investigate novel therapeutic options

Patients suffering from von Willebrand disease (VWD) have reduced quality-of-life despite current treatment options. Moreover, innovation in VWD therapeutic strategies has essentially stalled, and available treatments have remained unchanged for decades. Therefore, there is an unmet need to develop new therapeutic strategies for VWD patients, especially for the large portion of those with VWD-type 1. Due to species differences, the available VWD murine models are not suitable for preclinical studies, making it difficult to test new therapeutic approaches in vivo. With this in mind, we generated mice selectively expressing human von Willebrand factor (VWF) and human GPIbα. Because this fully humanized model was found to express low VWF (12%) and factor VIII (FVIII) (40%) levels with normal multimer profile and activity/antigen ratio, we repositioned it as a VWD-type 1 model (hVWD1 mice). In depth characterization of this model confirmed VWD-type 1 features with a decrease in platelet adhesion and thrombus formation in vitro. In vivo, a moderate bleeding phenotype was observed which was corrected upon the administration of recombinant-VWF or upon histamine-induced release of endothelial VWF. In search of new therapeutic options for VWD, we designed a bispecific single-domain antibody that bridges VWF to albumin (KB-V13A12). Remarkably, a single subcutaneous administration of KB-V13A12 coincided with a sustained 2-fold increase in VWF antigen levels for up to ten days and normalized hemostasis in a tail-clip model in hVWD1 mice. Here, we describe the development of our unique humanized mouse model for VWD-type 1 and a promising new therapeutic that corrected hemostasis in these mice.

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.

Clinical, Phenotypic and Genotypic Characteristics of Von Willebrand Disease in Afro-Caribbeans: Results From a Study in Martinique Island, French West Indies

BACKGROUND

Several cohort studies have investigated the molecular basis of von Willebrand disease (VWD); very few have focused on the Afro-Caribbean population.

OBJECTIVES

To determine the genotypic and phenotypic characterization of VWD in a large cohort of Afro-Caribbean patients living in Martinique.

MATERIALS AND METHODS

A total of 31 families comprising 63 Afro-Caribbean patients with VWD were enrolled. A standardized questionnaire and blood samples were collected for biological and molecular genetic analyses of von Willebrand factor (VWF). The impact of new missense variants has been predicted by in silico studies.

RESULTS

The median age of patients was 53 years (range 9-99). The most frequent symptoms were menorrhagia (49%), easy bruising (44%) and prolonged bleeding after tooth extraction (42%). Fifteen patients (24%) had quantitative deficiencies of VWF, of whom 13 (21%) were assigned as VWD-type 1, 1 (1%) as VWD-type 1C and 1 (2%) as VWD-type 3. Forty-five patients were diagnosed with VWD-type 2 (qualitative defects of VWF) (71%). VWD-type 2A was the most frequent, with 36 patients. Seven patients had VWD-type 2M and two patients had VWD-type 2B. Three patients (5%) had an indeterminate effect of the VWF defect due to ISTH BAT at 0. Forty-eight different VWF variants, including 4 novel variants, were identified in 63 patients. The variants consisted of 34 (71%) missense, 7 (15%) synonymous, 3 (6%) frameshifts, 2 (4%) small deletions and 2 (4%) gene conversions.

CONCLUSIONS

This study emphasizes the unique distribution of genotypes in our cohort of Afro-Caribbean VWD patients living in Martinique.

ESSENTIALS

Genotype-phenotype correlation was assessed in VWD Afro-Caribbean patients with one or more VWF variants. Menorrhagia, easy bruising and prolonged bleeding after tooth extraction are common in VWD patients. Efforts to increase the awareness and diagnosis of VWD have contributed to a better identification of patients with bleeding disorders.

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.

Platelet function analyzer (PFA-100) in patients with mild-to-moderate bleeding disorders and bleeding disorder of unknown cause

BACKGROUND

The sensitivity of the platelet function analyzer (PFA-100, Dade Behring Inc) was shown to be high for the detection of von Willebrand disease (VWD), but limited for platelet function defects.

OBJECTIVES

To study the diagnostic utility of PFA-100 in mild-to-moderate bleeding disorders and bleeding disorder of unknown cause (BDUC).

METHODS

PFA-100 closure times (CTs) were measured with collagen-epinephrine (EPI) and collagen-adenosine diphosphate (ADP) cartridges in 818 patients with mild bleeding disorders from the Vienna Bleeding Biobank. Patients on anticoagulation or antiplatelet therapy or thrombocytopenic patients were not included.

RESULTS

Only 2% of the 532 BDUC patients had prolonged CTs in PFA (EPI) and PFA (ADP), and 64% in either PFA (EPI) or PFA (ADP). In total, 34% of BDUC patients did not have prolonged CTs in PFA (EPI) or PFA (ADP). These rates were similar to patients with coagulation factor deficiencies (n = 27). The rate of pathologic CTs was significantly higher in patients with VWD (n = 79) and, although less pronounced, in platelet function defect (n = 180). In 15 of 18 (83%) VWD patients with von Willebrand factor (VWF) antigen and/or VWF ristocetin cofactor activity levels <30 IU/dL, the PFA-100 was prolonged in both cartridges. No association of the PFA-100 with the bleeding severity was observed in BDUC patients. However, prolonged CTs were associated with higher age, lower hematocrit, lower VWF antigen or VWF ristocetin cofactor activity levels, lower platelet counts, and higher fibrinogen levels in BDUC patients.

CONCLUSION

We could not confirm a diagnostic utility for the PFA-100 in mild-to-moderate bleeding disorder patients, and specifically BDUC. No association between PFA-100 results and bleeding severity was observed in BDUC patients.

Translation and Cultural Adaptation of the ISTH-Bleeding Assessment Tool to European Portuguese

INTRODUCTION

A distinctive bleeding history is the first diagnostic stage of congenital hemorrhagic diseases. Furthermore, since it is in fact an assessment of the patient's phenotype, it is not a (mere) complementary diagnostic method or test - it is an integral and intrinsic step to establish the patient's clinical history, which is a medical act. The International Society on Thrombosis and Haemostasis-Bleeding Assessment Tool (ISTH-BAT) is a standardized bleeding assessment tool used during the diagnostic workup of suspected bleeding disorders. This study aimed to translate and culturally adapt the ISTH-BAT questionnaire to the European Portuguese language.

METHODS

The translation and cultural adaptation were based on the International Society for Pharmacoeconomics and Outcomes Research Guidelines and initiated after obtaining permission from the authors. The process involved three English to European Portuguese independent forward translations and a back translation. Discrepancies were gradually resolved. A harmonized version was presented to hemophilia patients and hemophilia carriers for cognitive debriefing.

RESULTS

The forward and back translations did not produce important discrepancies. However, some issues were identified in the cognitive debriefing, which led to the cultural adaptation of medical terms for better understanding.

CONCLUSION

A formal translation and cultural adaptation process ensures that the new version maintains the same concepts as the original. After translation, several changes were necessary to ensure that the questionnaire was understandable by non-medical patients. We propose a European Portuguese version of the ISTH-BAT, which will require validation in further studies.

Emicizumab in Type 3 von Willebrand Disease: Report of a Case with an Alloantibody and Literature Review

Type 3 von Willebrand disease (VWD), the most severe form of VWD, is an inherited recessive bleeding disorder caused by the complete deficiency of von Willebrand factor (VWF). The reported prevalence is 1 per million but varies worldwide according to the frequency of consanguineous marriages. The clinical phenotype is characterized not only by mucocutaneous bleedings, but also by hemarthroses and muscle hematoma, as in patients with moderate hemophilia. Long-term prophylaxis with factor (F)VIII/VWF concentrates is recommended in patients with a history of severe and frequent bleeds. A rare complication of replacement therapy is the development of alloantibodies against VWF, with the consequences of an ineffective therapy and risk of anaphylactic reactions upon treatment. Emicizumab is the first bispecific monoclonal antibody that mimics FVIII coagulant activity and is approved for prophylaxis of bleeding in patients with inherited hemophilia A with or without inhibitors and recently also for acquired hemophilia. In this manuscript we report and discuss available data in the literature on the use of emicizumab in type 3 VWD and describe the case of a female patient with type 3 VWD with a history of alloantibodies against VWF and posttransfusion anaphylaxis, recently and successfully put on off-label prophylaxis with emicizumab.

Clinical utility of panel-based genetic sequencing for von Willebrand disease

Background

von Willebrand disease (VWD) is the most prevalent inherited bleeding disorder with a wide spectrum of causative variants. Next-generation sequencing analyzes the entire VWF gene and provides concomitant assessment of other genes, allowing differentiation between genocopies.

Objectives

We aimed to assess the clinical impact of panel-based sequencing in all VWD patients sequenced at UZ Leuven.

Methods

We conducted a single-center retrospective study of all patients with confirmed or suspected VWD who were screened with panel-based whole-exome sequencing. Presequencing diagnosis was performed using laboratory measures of VWF activity and quantity. Postsequencing diagnosis was informed by variant curation in combination with laboratory measures. We measured clinically meaningful changes in the pre- vs postgenetic sequencing diagnosis and subtyping.

Results

The study included 108 patients. The population was predominantly composed of pediatric patients <18 years old (77/108; 71%) and females (66/108; 61%). The largest presequencing subgroup was those with low VWF (61/108; 56%), followed by type 1 VWD (21/108; 19%) and type 2 not otherwise specified (18/108; 17%). A clinically meaningful change in management occurred in 19% (20/108) of the study population. The largest effect was seen in the presequencing type 2 group (16/24; 67%). In the type 2 group who could not be accurately subtyped into 2A/B/M/N prior to sequencing (type 2 not otherwise specified), 15/18 (83%) were able to be subtyped or given a different diagnosis postsequencing.

Conclusion

Panel-based sequencing for VWD in a well-selected cohort, particularly those with type 2 and type 3 VWD, was clinically relevant in differentiating genocopies, directing therapies, and family planning. Sequencing in those with low VWF and type 1 VWD rarely changed management.

Pregnancy loss in individuals with von Willebrand disease and unspecified mucocutaneous bleeding disorders: a multicenter cohort study

BACKGROUND

While bleeding around pregnancy is well described in von Willebrand disease (VWD), the risk of pregnancy loss is less certain.

OBJECTIVES

We aimed to describe the frequency of pregnancy loss in females with VWD compared with those with a similar mucocutaneous bleeding phenotype and no VWD or compared with nonbleeding disorder controls.

METHODS

Female patients were consecutively approached in 8 specialty bleeding disorder clinics between 2014 and 2023. The VWD group was defined as having von Willebrand factor (VWF) antigen and VWF activity levels, each <0.50 IU/mL on ≥2 occasions, and a condensed MCMDM-1 score of ≥4. The non-VWD mucocutaneous bleeding disorder group had VWF levels ≥ 0.50 IU/mL on ≥2 occasions and an MCMDM-1 score ≥ 4. A nonbleeding disorder control group was recruited in pregnancy from a low-risk maternity clinic.

RESULTS

There were 150 females in the VWD group, 145 in the non-VWD mucocutaneous bleeding disorder group, and 137 in the control group. There was a similar frequency of individuals with ≥1 loss in the VWD group (45.3%, 68/150), the non-VWD group (56.6%; 82/145; -11.2%; 97.5% CI, -24.2%, 1.8%), and the nonbleeding disorder control group (37.2%; 51/137; 8.1%; 97.5% CI, -4.9%, 21.1%). Using a logistic regression, the odds ratio of pregnancy losses in the VWD group vs the non-VWD group was 0.94 (95% CI 0.65, 1.36). All groups experienced more recurrent losses compared with the literature.

CONCLUSION

There was no statistically significant difference in risk of pregnancy loss between females with VWD, females with a similar mucocutaneous bleeding phenotype, and nonbleeding disorder controls.

Current Diagnosis of Bleeding Disorders in Lower Income Countries

There have been considerable advances in diagnosing and treating bleeding disorders. But the scenario remains dismal in resource-constrained settings in low and lower-middle-income countries (LMICs). Seventy-five percent of the patients with inherited bleeding disorders do not get diagnosed in LMICs. In resource-constrained settings, infectious disease and malignancies take the major focus. Bleeding disorders do not get prioritised in LMICs, and this leads to underdiagnoses and suboptimal treatment. There are various challenges like financial status, inadequacy of health care infrastructure, lack of patient registry and lack of awareness across medical staff, general population and government stakeholders. The lack of skilled laboratory personnel and laboratory infrastructure for optimal bleeding disorder diagnosis adds on to the problem. World Federation of Hemophilia (WFH) has been at the forefront in developing strategies to overcome some of these inadequacies; however, more active participation of the stakeholders including patients, medical professionals and policy makers is the need of the hour. This review highlights the different challenges in LMICs in diagnosing bleeding disorders, the gap between high-income countries and LMICs and the possible strategies in closing the gap.

The severe von Willebrand disease variant p.M771V leads to impaired anterograde trafficking of von Willebrand factor in patient-derived and base-edited endothelial colony-forming cells

BACKGROUND

von Willebrand disease (VWD) is the most common inherited bleeding disorder caused by quantitative or qualitative defects in von Willebrand factor (VWF). The p.M771V VWF variant leads to a severe bleeding phenotype in homozygous patients. However, the exact molecular mechanism remains unclear, which prevents personalized treatment of those VWD patients.

OBJECTIVES

This study aimed to characterize the underlying molecular mechanisms of the p.M771V variant in multiple representative ex vivo cell models.

METHODS

Endothelial colony-forming cells (ECFCs) were isolated from venous blood of VWD patients from the Willebrand in the Netherlands cohort carrying homozygous and heterozygous p.M771V VWF variants. The p.M771V variant was also introduced in cord blood-derived ECFCs (CB-ECFCs) through adenine base editing and was overexpressed in HEK293 cells. Biosynthesis, storage, and secretion of VWF was studied using biochemical methods and confocal microscopy.

RESULTS

Two unrelated homozygous p.M771V patients presented with very low VWF activity and antigen levels in plasma. Patient ECFCs showed impaired uncleaved VWF processing into mature VWF, with secreted VWF being severely reduced when compared to ECFCs of healthy donors. Multimer analysis of p.M771V ECFCs showed a deficiency of high molecular weight VWF multimers. Immunofluorescent staining revealed VWF retention in the endoplasmic reticulum; this was confirmed in various populations of base-edited CB-ECFCs harboring the p.M771V variant.

CONCLUSION

The severe endothelial phenotype observed in patient-derived p.M771V ECFCs, HEK293 cells, and an original base-edited CB-ECFC modeling system show that endoplasmic reticulum retention of VWF and failure to undergo subsequent proteolytic processing underpins the severe bleeding phenotype of patients with homozygous variants at M771.

Does the VWF:CB Assay Help to Diagnose von Willebrand Factor Deficiency in Patients With a Bleeding Disorder of Unknown Cause?

INTRODUCTION

The entity entitled bleeding disorder of unknown cause (BDUC) qualifies individuals displaying a mild haemorrhagic profile but normal routine coagulation tests. This study was designed to evaluate whether collagen-binding assay for von Willebrand Factor (VWF) measurement (VWF:CB) could allow to diagnose VW disease in such patients.

METHODS

A large screening was conducted prospectively in two University Hospitals, using the bleeding assessment tool (BAT) recommended by the International Society of Thrombosis and Hemostasis. Patients with an abnormal BAT were confirmed to have a normal complete hemostatic evaluation. A large range of VWF assays was then carried out on a new blood sample for the 68 individuals (91% women) thus identified. Of note, five VWF:CB using different types of collagen were performed, as well as a comprehensive sequencing of the VWF gene.

RESULTS

Of this cohort, only 3 individuals (all blood group O), had a VWF:CB between 40 and 50 IU/dL. No unknown anomaly of the VWF gene was disclosed. Of note, 54% of these patients had unexplained abnormal occlusion times on PFA-200.

CONCLUSION

This study identified 68 cases of BDUC, after screening of a large population, indicating a low incidence. Only 3 cases were potentially confirmed as displaying moderate von Willebrand disease. VWF:CB tests were globally normal in the 65 other patients of the cohort.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT0279220.

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.

Coagulation factors VIII and factors IX testing practices in China: Results of the 5-year external quality assessment program

BACKGROUND AND AIMS

Testing for coagulation factors VIII (FVIII) and IX (FIX) plays significant importance in the diagnostic and treatment of hemophilia A and B. External quality assessment (EQA) scheme aimed to assess the participants' performance of testing for coagulation factors and identify shortcomings in clinical practice. This study aimed to investigate the performance trends of the participating laboratories in China national external quality assessment Scheme (China NEQAS) for FVIII and FIX over a five-year period (2019-2023).

MATERIALS AND METHODS

A total of ten external quality assessment (EQA) rounds were conducted from 2019 to 2023 in the China NEQAS for FVIII and FIX. The distribution of method, reagent and instrument were calculated. The trends of method- specific inter-laboratory coefficient of variation (CV) and pass rates were analyzed over 5 years. The dilutions for coagulation factor testing were also investigated.

RESULTS

All laboratories use one-stage assays to detect FVIII and FIX activity. The inter-laboratory overall CV decreased year by year (10.9 % to 9.3 % for FVIII and 13.5 % to 10.2 % for FIX), and the laboratory pass rate steadily increased (88.0 % to 93.4 % for FVIII and 81.3 % to 92.7 % for FIX). The majority of laboratories employed a single dilution methodology for the assessment of FVIII and FIX activity. The interlaboratory CV was elevated for the Siemens reagent (Actin FSL) during analysis of moderately abnormal FIX concentrations of EQA samples in most batches.

CONCLUSIONS

The implementation of the external quality assessment has contributed to facilitate the enhancement of testing quality. Chromogenic assay is a supplement to accurate determination when necessary. Laboratories may choose to perform dilution tests or direct assays to identify the presence of inhibitors, particularly when they are suspected.

Effective Pediatric Blood Management in Craniosynostosis Surgery: A Long-Term Update

BACKGROUND

Blood transfusion is common in cranial vault surgery, and protocolized efforts to minimize transfusion have been reported in recent years. This study assesses the long term, prospective outcomes of a pediatric blood management protocol for the cranial vault reconstruction (CVR) population.

MATERIALS AND METHODS

Data from a retrospective control cohort and a prospective cohort employing a protocol for preoperative hematologic optimization of patients undergoing CVR from January 2015 to October 2023 was reviewed. Preoperative hemoglobin (Hgb) determined the preoperative protocol. Intraoperative tranexamic acid (TXA) and/or aminocaproic acid, cell-saver technology, and postoperative iron or erythropoietin alfa supplementation were also used in the protocol. For statistical analysis, P <0.05 was deemed significant.

RESULTS

The cohort consisted of 194 successive patients (20 control and 174 treatment). Age, sex, and weight were not significantly different between groups. Mean postoperative Hgb was significantly higher in the control group ( P <0.01). No difference was observed in Hgb at discharge between control and treatment groups. Mean estimated blood loss, volume of intraoperative packed red blood cells, rate of packed red blood cell transfusion, and mean total transfusion volume during hospitalization were significantly higher in the control group compared with the treatment group ( P <0.01). Mean length of stay did not differ between groups.

CONCLUSION

Efforts to optimize blood management in the CVR population are critical. This prospective study represents a robust and reproducible protocol for pediatric blood management with significant reductions in transfusion requirements.

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.

Challenges and considerations of genetic testing in von Willebrand disease

von Willebrand disease (VWD) is the most common inherited bleeding disorder characterized by defects in the quantity or function of the von Willebrand factor (VWF). The diagnosis of VWD is complex, requiring a battery of tests to evaluate the amount, functions, and multimeric structure of the VWF glycoprotein. The diagnosis can also be accomplished or confirmed by sequencing the VWF gene (VWF). Genetic testing of VWF has been around for 4 decades following the cloning of VWF, and nowadays, it has been integrated into the diagnostic panel of VWD. With the introduction of next-generation sequencing, genetic analysis of the VWF has become more practical than it was in the past, when Sanger sequencing was used. A number of laboratories have applied or started to use genetic testing with next-generation sequencing for VWD diagnosis. Considering the increasing application of genetic testing in VWD and the wide availability and decreasing cost of gene sequencing, we sought to discuss the challenges and considerations involved in applying genetic testing to VWD.

Early Postoperative Changes in Von Willebrand Factor Activity Are Associated With Future Bleeding and Stroke in HeartMate 3 Patients

Hemocompatibility-related adverse events (HRAEs), particularly gastrointestinal bleeding, remain a frequent complication after left ventricular assist device (LVAD) implantation. The current study sought to describe and analyze whether early (<60 days) postoperative von Willebrand factor (VWF) activity assays predict the risk of gastrointestinal bleeding and stroke. A prospective single-center study including 74 HeartMate 3 device recipients between 2016 and 2023 was undertaken. The postoperative trajectory of the VWF profile was analyzed using linear mixed-effect models and Cox models were used to quantify associations between an early postoperative dip (≤0.7) in VWF activity assay measurements and late outcomes. Preoperatively, the mean VWF:Activity (Act)/Antigen (Ag) and VWF:Collagen Binding (CB)/Ag ratios were 0.94 (95% confidence interval [CI] = 0.81-1.02) and 0.95 (95% CI = 0.80-1.03), respectively, decreasing to 0.66 (95% CI = 0.57-0.73) and 0.67 (95% CI = 0.58-0.74) within 40 days ( p < 0.05). In patients with VWF:CB/Ag and VWF:Act/Ag ratios ≤0.7 significantly more gastrointestinal bleeding (hazard ratio [HR]: 2.53; 95% CI = 1.1-5.8, and HR: 3.7; 95% CI = 1.5-9.2, respectively) and hemorrhagic stroke events (HR: 3.5; 95% CI = 1.6-7.6 and HR: 4.9; 95% CI = 2.1-11.7, respectively) were observed throughout the entire late (>60 days) postoperative period. In patients with VWF:Act/Ag ratio ≤0.7 less ischemic stroke events were observed (HR: 0.11; 95% CI = 0.01-0.85). In conclusion, VWF:Act/Ag and VWF:CB/Ag ratios ≤0.7 in the early postoperative phase can be used as biomarkers to predict HRAEs during long-term LVAD support.

Genetic variations of type 2 and type 3 von Willebrand diseases in Thailand

AIMS

Von Willebrand disease (VWD) is an inherited haemostatic disorder with a wide range of bleeding phenotypes based on von Willebrand factor (VWF) levels. Multiple assays including VWF gene analysis are employed to correctly diagnose VWD and its subtypes. However, data on VWF mutations among Southeast Asian populations are lacking. We, therefore, aimed to explore genetic variations in Thai patients with type 2 and type 3 VWD by whole exome sequencing (WES).

METHODS

In this multicentre study, Thai patients with type 2 and type 3 VWD, according to the definitions and VWF levels recommended by the international guidelines, were recruited. WES was performed using DNA extracted from peripheral blood in all cases. The novel variants were verified by Sanger sequencing.

RESULTS

Fifteen patients (73% females; median age at diagnosis 3.0 years) with type 2 (n=12) and type 3 VWD (n=3) from 14 families were enrolled. All patients harboured at least one VWF variant. Six missense (p.Arg1374Cys, p.Arg1374His, p.Arg1399Cys, p.Arg1597Trp, p.Ser1613Pro, p.Pro1648Arg) and one splice-site (c.3379+1G>A) variants in the VWF gene were formerly described. Notably, six VWF variants, including three missense (p.Met814Ile, p.Trp856Cys, p.Pro2032Leu), one deletion (c.2251delG) and two splice-site (c.7729+4A>C, c.8115+2delT) mutations were novelly identified. Compound heterozygosity contributed to type 2 and type 3 VWD phenotypes in two and one patients, respectively.

CONCLUSIONS

Type 2 and type 3 VWD in Thailand demonstrate the mutational variations among VWF exons/introns with several unique variants. The WES-based approach potentially provides helpful information to verify VWD diagnosis and facilitate genetic counselling in clinical practice.

Contrasting Approaches in the Implementation of GRADE Methodology in Guidelines for Haemophilia and Von Willebrand Disease

INTRODUCTION

The 2024 ISTH clinical practice guideline (CPG) for treatment of congenital haemophilia, the NBDF-McMaster Guideline on Care Models for Haemophilia Management, and ASH ISTH NBDF WFH guidelines on the diagnosis and management of VWD all utilised GRADE methodology.

AIM

Discuss missed opportunities and the methodological approach of the ISTH Guideline in contrast to how GRADE was previously applied in rare diseases.

METHODS

Critically analyse the methodology of each guideline along with best practices in the use of GRADE. Where applicable, the WFH Guidelines for the Management of Haemophilia were analysed.

RESULTS

Important differentiating features in applying GRADE were identified. Where a strong evidence base is lacking, data other than those from randomized controlled trials, which may not always be justified, need to be considered, including incorporation of outcomes important to people living with the disease. Justification and stakeholder input to prioritize questions requiring a new guideline, panel composition with necessary patient participation and content expertise were also found to be significant differentiating features.

CONCLUSION

The puristic approach taken in the ISTH Guideline development process, without consideration of accepted adaptations to GRADE implementation, created a missed opportunity for progressing haemophilia care, leading to guideline recommendations that have been widely deemed invalid and obsolete by expert healthcare professionals and by those living with the condition, the very people who are expected to implement or bear the impact of the recommendations. Lessons learnt from this comparative analysis should guide future guideline development and encourage collaboration to further advance haemophilia.

von Willebrand disease and heavy menstrual bleeding: when and how to test

von Willebrand disease (VWD) is a common inherited bleeding disorder caused by von Willebrand factor (VWF) deficiency and is an important cause of heavy menstrual bleeding in young patients. A clinical evaluation using standardized bleeding scores helps determine when screening hemostatic testing is indicated by identifying patients with a moderate or high probability of an inherited bleeding disorder. The diagnosis of VWD is made when VWF levels are under 30 IU/dL or between 30 and 50 IU/dL when there is a positive bleeding history. Activity levels above 100 IU/dL have a high negative predictive value. Multiple factors, including stress from acute bleeding and anemia, pregnancy, and medications, can affect VWF levels, hence testing for VWD is best performed when a person's health is at its baseline level, although this is not always possible in clinical practice. Variation in assay methodologies measuring VWF activity can have a significant impact on the diagnostic evaluation, and it is important for clinicians to be familiar with the limitations of the assay used by their local or reference laboratory. Genetic testing can be useful in establishing the VWD subtype and providing accurate reproductive counseling but is not required to make a diagnosis.

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.

Genetic variants, thrombocytopenia, and clinical phenotype of type 2B von Willebrand disease: a median 16-year follow-up study

BACKGROUND

Type 2B von Willebrand disease (VWD) is a bleeding disorder caused by gain-of-function variants in the VWF gene. The laboratory and clinical phenotype of type 2B VWD is heterogeneous.

OBJECTIVES

We investigated associations between genotype and phenotype over a median of 16 years follow-up in a large cohort of well-characterized patients.

METHODS

We included 64 genetically confirmed type 2B VWD patients from the national multicenter "Willebrand in the Netherlands" study and retrospectively collected clinical and laboratory data from electronic patient records. We analyzed associations between genotype and thrombocytopenia, bleeding phenotype, and events leading to endothelial activation and von Willebrand factor (VWF) secretion, including surgery, desmopressin administration, pregnancy, and delivery.

RESULTS

Thrombocytopenia manifested in 67.2% of patients, with varying occurrences between genetic variants (p.Arg1306Trp: 75.0%, p.Arg1308Cys: 58.3%). The most important determinant of thrombocytopenia was the p.Arg1306Trp VWF variant (odds ratio, 25.1). Platelet counts strongly varied over time and were continuously <150 × 109/L in 37.5% of patients with p.Arg1306Trp vs 8.3% in p.Arg1308Cys. In our analysis, endothelial activation was not an independent determinant (odds ratio, 1.3) for thrombocytopenia occurrence. No association was found between thrombocytopenia and cumulative bleeding scores or annual bleeding rates. Four women showed declining platelet counts in all full-term pregnancies (n = 8) during the third trimester with a sharp decrease in the week before delivery. Postpartum hemorrhage, defined as >500 mL estimated blood loss at delivery, occurred in 5 of 8 deliveries, despite prophylactic treatment with VWF concentrates.

CONCLUSION

This study reveals a strong association between VWF variant p.Arg1306Trp and thrombocytopenia in type 2B VWD patients.

Low von Willebrand factor-unraveling an enigma wrapped in a conundrum

The 2021 ASH ISTH NHF WFH guidelines recommendation that patients with von Willebrand factor (VWF) levels of 30 to 50 IU/dL and an increased bleeding phenotype be categorized as type 1 von Willebrand disease (VWD) rather than Low VWF has proved controversial. However, in support of that decision, recent data have demonstrated that individuals with partial quantitative VWF deficiency exhibit an age-dependent evolving phenotype and confirmed that Low VWF represents a subgroup within heterogeneous type 1 VWD. Nonetheless, type 1 VWD heterogeneity continues to pose significant diagnostic challenges. In this Forum article, we address outstanding issues critical to preventing the inappropriate overdiagnosis of type 1 VWD while maximizing access to healthcare and minimizing diagnostic delays. In addition, we propose an algorithm for type 1 VWD diagnosis. This algorithm pays special attention to individuals with plasma VWF levels in the 30 to 50 IU/dL range who have no or minimal bleeding history and have not yet been exposed to significant hemostatic challenges.

Innovative Diagnostic Solutions in Hemostasis

Hemostasis describes the process of blood clotting homeostasis. Hemostasis reflects a balance of procoagulant and anticoagulant mechanisms that aim to prevent both bleeding and thrombosis. If hemostasis is disrupted, and bleeding or thrombosis occur, then laboratory testing may ensue to either diagnose the reason for bleeding or thrombosis, or to manage patients under therapy or treatment for bleeding or thrombosis. A wide range of tests of hemostasis are available to laboratories and to clinicians, from routine coagulation assays to specialized hemostasis assays and platelet function. In the current narrative review, we highlight some of the history of innovative diagnostic solutions, such as the integration of chemiluminescence and flow cytometry in the hemostasis diagnostic armamentarium, as well as providing a glimpse to the possible future of diagnostic hemostasis testing. Future directions include the potential for artificial intelligence in diagnostics, the development of more global test systems that can assess both primary and secondary hemostasis, and several innovations to enable the ongoing evolution of therapies to rebalance hemostasis and requiring precise monitoring. This review underscores the ongoing need for innovation to enhance the diagnostic landscape of hemostasis, ensuring better patient outcomes through more accurate and efficient diagnostic methods.

Unravelling the spectrum of von Willebrand factor variants in quantitative von Willebrand disease: results from a German cohort study

BACKGROUND

Von Willebrand disease (VWD), the most prevalent hereditary bleeding disorder, results from deficiency of von Willebrand factor (VWF).

OBJECTIVES

This large cohort study aims to offer a comprehensive exploration of mutation spectra and laboratory features in quantitative VWF deficiencies, shedding light on genetic underpinnings and genotype-phenotype associations.

METHODS

Our cohort consisted of 221 Caucasian index patients with quantitative VWD, along with 47 individuals whose plasma VWF levels fell within the lower normal boundaries (50-70 IU/dL). We conducted comprehensive VWF assays and genetic analyses, encompassing VWF gene sequencing, copy number variation investigations, and bioinformatic assessments.

RESULTS

Following International Society on Thrombosis and Haemostasis-Scientific and Standardization Committee VWF guidelines, 77 index patients were characterized as having type 1 VWD (VWF antigen [VWF:Ag] < 30 IU/dL), 111 as having type 1 VWD (VWF:Ag, 30-50 IU/dL), and 33 as having type 3 VWD. Mutation detection rates were 88%, 65%, and 92%, respectively. Notably, blood group O overrepresentation was evident in type 1 with VWF:Ag of 30 to 50 IU/dL, particularly among mutation-negative patients, suggesting a potential causal role of blood group O. A total of 223 VWF variants, comprising 147 distinct variations, were identified in quantitative VWD patients, of which 57 were novel variants (39%). Additionally, approximately 70% of individuals with VWF levels within the lower normal boundaries (50-70 IU/dL) displayed VWF variants.

CONCLUSION

Our data advance our understanding of the molecular mechanisms underlying quantitative VWD, offering valuable insights for future research and clinical management. Distinct mutation patterns were observed among subgroups, particularly the contrast between type 1 VWD (VWF:Ag < 30 IU/dL) and type 1 VWD (VWF:Ag, 30-50 IU/dL), an area with limited prior investigation.

Matched cohort study evaluating the hemostatic efficacy of fibrin sealant versus conventional approaches following dental surgery in patients with hemophilia

Patients with hemophilia frequently require supplementary interventions, either invasive (suturing, gel foam, or cauterization) or non-invasive (fibrin sealant/glue), to attain hemostasis post dental procedures. This study aimed to compare the efficacy of fibrin sealant against traditional methods for achieving hemostasis post dental surgery. The medical records of patients with factor VIII or IX deficiency, or von Willebrand disease, who underwent dental procedures in the Department of Dentistry, Seth GSMC and KEM Hospital, were evaluated for inclusion in this retrospective matched cohort study. Cohort-1 included those treated with a fibrin sealant (Tisseel Lyo) with/without traditional hemostatic measures post-procedure, while cohort-2 (controls) included those in whom no fibrin sealant was used. A total of 128 patients, 64 in each group, were evaluated. There was no statistically significant difference in demographics, disease-related variables, dental complaints, or preoperative treatment given between the groups. However, there was a significant reduction (P < 0.001) in the requirement for secondary procedures for hemostasis (suturing, gel foam application, and/or cauterization) and postoperative requirement for factor replacement (P = 0.003) in the fibrin glue group as compared to the controls. In this study, fibrin sealant demonstrated superior efficacy in mitigating the necessity for active hemostasis control.

Bleeding disorder of unknown cause: an illustrated review on current practice, knowledge gaps, and future perspectives

In more than half of the individuals with a clinically relevant bleeding tendency who are referred to hemostasis experts, no biological etiology can be found after extensive laboratory testing. These persons are diagnosed with an unexplained bleeding tendency or "bleeding disorder of unknown cause" (BDUC). The mucocutaneous bleeding phenotype of individuals with BDUC is generally comparable to that of individuals with inherited bleeding disorders such as von Willebrand disease or platelet function disorders. BDUC definitions applied in literature are heterogeneous, but all comprise 2 main criteria: (1) there is an increased bleeding tendency based on the clinical view of the physician and/or an increased bleeding score; (2) no abnormalities are found with available hemostasis laboratory tests. This is reflected in the recent published BDUC definition by the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis, stating that BDUC is a diagnosis of exclusion, characterized by normal hemostatic investigations despite a clinically significant bleeding tendency. Importantly, other nonhemostatic and acquired causes of bleeding should be excluded, but details on exclusion criteria and associated diagnostic testing remain undefined. Patients and health care providers are challenged by the uncertainty and lack of formal diagnosis particularly as there is no clear consensus regarding treatment. Research on the diagnostic value of new laboratory tests in individuals with BDUC has not yet been productive. In this illustrative review, the current practice and knowledge gaps in BDUC are addressed, previous research on BDUC is outlined and future directions with outstanding questions for future research in BDUC are highlighted.

A core outcome set for prophylaxis and perioperative treatment of von Willebrand disease: The coreVWD initiative

INTRODUCTION

Treatment options are expanding for von Willebrand disease (VWD). A core outcome set (COS)-a minimum set of agreed-upon outcomes to be used in every clinical trial for a given condition-provides guidance on which outcomes are most important to measure to ensure necessary data is collected for a variety of stakeholders and enable comparison across products and trials.

AIM

coreVWD aimed to develop a COS for trials for prophylaxis and perioperative treatments for VWD.

METHODS

A modified Delphi consensus process was used to condense/prioritize a long list of potential outcomes. Over three Delphi rounds, a multi-stakeholder panel (patients, clinicians, pharmaceutical company representatives, HTA organizations, payer, and government organization representatives) rated each outcome from 1 (not important to include in a COS) to 9 (essential to include). Outcomes were eliminated or retained based on pre-determined criteria; a special provision to elevate patient priorities was included. An in-person consensus meeting was held after Delphi round 2.

RESULTS

Thirty-nine panellists participated. The final COS for prophylaxis treatment included 18 outcomes, seven of which are part of a special subset selected for women, girls and people with the potential to menstruate. There were 11 outcomes in the final perioperative branch COS. Six outcomes overlapped both COS.

CONCLUSIONS

The coreVWD COS represents a consensus list of outcomes for clinical trials for both factor and non-factor VWD therapies. These outcomes will be useful across the lifecycle of a product, from clinical development through regulatory and market access phases and into patient-provider decision-making.

Patient-reported data on the severity of Von Willebrand disease

INTRODUCTION

The severity of Von Willebrand disease (VWD) is currently based on laboratory phenotype. However, little is known about the severity of the patient's experience with the disease. The most recent VWD guidelines highlight the need for patient-reported outcomes (PROs) in VWD.

AIM

The study aimed to investigate the patient-perspective on VWD severity and to identify key factors that determine the severity of disease experienced by patients.

MATERIALS AND METHODS

Patients participated in a nationwide cross-sectional study on VWD in the Netherlands (WiN-study). Patients filled in a questionnaire containing questions on the experienced severity of VWD (4-point scale), bleeding score (BS) and quality of life (QoL).

RESULTS

We included 736 patients, median age of 41.0 years (IQR 23.0-55.0) and 59.5% were women. A total of 443 had type 1, 269 type 2 and 24 type 3 VWD. Self-reported severity of VWD was categorized as severe (n = 52), moderate (n = 171), mild (n = 393) or negligible (n = 120). Classification by historically lowest FVIII:C levels < 0.20 IU/mL as a proxy for severe VWD aligned with patient-reported severity classification with a 72% accuracy. Type 3 VWD (OR = 4.02, 95%CI: 1.72-9.45), higher BS (OR = 1.09, 95%CI: 1.06-1.11), female sex (OR = 1.36, 95%CI: 1.01-1.83), haemostatic treatment in the year preceding study inclusion (OR = 1.53, 95%CI: 1.10-2.13) and historically lowest VWF:Act levels (OR = 0.26, 95%CI: 0.07-1.00) were independent determinants of patient-reported severity.

CONCLUSION

This study shows that patient-reported data provide novel insights into the determinants of experienced disease severity. Our findings highlight the need for studies on PROs with validated questionnaires to assess the burden of VWD.

Heyde Syndrome Unveiled: A Case Report with Current Literature Review and Molecular Insights

Heyde syndrome, marked by aortic stenosis, gastrointestinal bleeding from angiodysplasia, and acquired von Willebrand syndrome, is often underreported. Shear stress from a narrowed aortic valve degrades von Willebrand factor multimers, leading to angiodysplasia formation and von Willebrand factor deficiency. This case report aims to raise clinician awareness of Heyde syndrome, its complexity, and the need for a multidisciplinary approach. We present a 75-year-old man with aortic stenosis, gastrointestinal bleeding from angiodysplasia, and acquired von Willebrand syndrome type 2A. The patient was successfully treated with argon plasma coagulation and blood transfusions. He declined further treatment for aortic stenosis but was in good overall health with improved laboratory results during follow-up. Additionally, we provide a comprehensive review of the molecular mechanisms involved in the development of this syndrome, discuss current diagnostic and treatment approaches, and offer future perspectives for further research on this topic.

Prevalence and characterization of anti-VWF antibodies in a population of patients with type 3 VWD

ABSTRACT

von Willebrand disease (VWD) is an inherited bleeding disorder caused by quantitative or qualitative defects in the von Willebrand factor (VWF) protein. Type 3 VWD has a severe bleeding phenotype caused by the absence of VWF, in which treatment usually involves replacement therapy with VWF-containing products. The immune system can react to the VWF product and form anti-VWF antibodies to neutralize or clear the VWF, which can compromise efficacy of treatment or lead to anaphylaxis. Current diagnostic testing is limited to the detection of anti-VWF antibodies that neutralize VWF binding to platelets by using a ristocetin cofactor assay. We set out to develop assays to identify both neutralizing and nonneutralizing antibodies to screen, quantify, and characterize anti-VWF antibodies in samples from the Zimmerman Program, a large multicenter study of patients with VWD. We detected anti-VWF immunoglobulin G (IgG) or IgM antibodies in 18% of 49 unrelated individuals with type 3 VWD. The antibodies ranged in concentration and consisted of 33% nonneutralizing and 67% neutralizing to factor VIII, collagen III, platelet glycoprotein Ib alpha (GPIbα), and/or collagen IV binding. Of the positive type 3 VWD samples, 8 of 9 were IgG, which were further subclassified into mostly IgG1 and IgG4 antibodies. Through a series of testing methods, we identified VWF-specific antibodies in 9 unrelated individuals with type 3 VWD with varying demographics, bleeding phenotypes, and genetic variants. This anti-VWF antibody testing strategy provides a useful tool to assess risk and better navigate treatment options for patients with type 3 VWD.

Utility of Global Hemostatic Assays in Patients with Bleeding Disorders of Unknown Cause

Bleeding disorder of unknown cause (BDUC) is a diagnosis of exclusion after exhaustive evaluation of plasmatic coagulation and platelet function. This review explores the utility of global hemostatic assays as confirmatory tests and in elucidating the pathophysiology of BDUC. Unlike traditional hemostatic tests that focus on coagulation factors, global assays are conducted both in plasma and also whole blood. These assays provide a more comprehensive understanding of the cell-based model of coagulation, aid in the identification of plasmatic factor abnormalities that may reduce hemostatic capacity, and allow for the assessment of impaired platelet-endothelial interactions under shear stress, as well as hyperfibrinolytic states. While clinical tests such as skin bleeding time and global assays such as PFA-100 exhibit limited diagnostic capacity, the role of viscoelastic testing in identifying hemostatic dysfunction in patients with BDUC remains unclear. Thrombin generation assays have shown variable results in BDUC patients; some studies demonstrate differences compared with healthy controls or reference values, whereas others question its clinical utility. Fibrinolysis assessment in vitro remains challenging, with studies employing euglobulin clot lysis time, plasma clot lysis time, and fluorogenic plasmin generation yielding inconclusive or conflicting results. Notably, recent studies suggest that microfluidic analysis unveils shear-dependent platelet function defects in BDUC patients, undetected by conventional platelet function assays. Overall, global assays might be helpful for exploring underlying hemostatic impairments, when conventional hemostatic laboratory tests yield no results. However, due to limited data and/or discrepant results, further research is needed to evaluate the utility of global assays as screening tools.

Type 2N von Willebrand disease: genotype drives different bleeding phenotypes and treatment needs

BACKGROUND

Type 2 Normandy von Willebrand disease (VWD2N) is usually perceived as a mild bleeding disorder that can be treated with desmopressin (DDAVP). However, VWD2N patients can be compound heterozygous or homozygous for different variants, with p.Arg854Gln (R854Q) being the most frequent causative one. There are limited data about the impact of 2N variants on VWD2N phenotype and DDAVP response.

OBJECTIVES

This study aims to describe the phenotype of VWD2N, including DDAVP response, according to genotype.

METHODS

VWD2N patients with a complete genotype/phenotype characterization by the French reference center for VWD, including MCMDM-1VWD bleeding score, were eligible to be included in the study. Results of the DDAVP trial were also collected.

RESULTS

A total of 123 VWD2N patients from the French registry were included in this study. Results were stratified according to the presence (R854QPos, n = 114) or absence (R854QNeg, n = 9) of at least 1 R854Q allele. Three R854QPos subgroups were further individualized: patients homozygous (R854QHmz, n = 55), compound heterozygous for R854Q and a null allele (R854Q/3, n = 48), or compound heterozygous for R854Q and another 2N variant (R854Q/2N, n = 11).

FVIII

C levels were significantly lower in R854QNeg and R854Q/3 patients compared with R854QHmz ones (P < .001 and P < .0001, respectively). R854QNeg patients were diagnosed earlier due to bleeding symptoms and had a higher bleeding score than R854QPos patients (P < .001). In DDAVP trial, FVIII:C survival was lower in VWD type 2N than in type 1 patients. R854QPos patients had a heterogeneous DDAVP response, which was best predicted by baseline FVIII:C level.

CONCLUSION

The heterogeneous genetic background of VWD2N drives different bleeding phenotypes and response patterns to DDAVP, underlining the clinical relevance of DDAVP trial to identify patients potentially eligible to alternative therapeutic options.

Awareness of von Willebrand disease among gynecologists: Investigating the referral of women with heavy menstrual bleeding to hematologists

Awareness of bleeding disorders, including von Willebrand disease, as a cause of heavy menstrual bleeding is low among gynecologists/obstetricians, potentially delaying diagnosis and appropriate treatment.

Examining variability in the diagnosis and management of people with bleeding disorders of unknown cause: communication from the ISTH SSC Subcommittee on von Willebrand Factor

BACKGROUND

Bleeding disorder of unknown cause (BDUC) is characterized by a bleeding phenotype in the setting of normal hemostatic testing. No standardized diagnostic criteria or treatment algorithms exist for people with BDUC. To address the unmet need, the International Society on Thrombosis and Haemostasis von Willebrand Factor Scientific Subcommittee performed a real-world survey aimed at addressing knowledge gaps, developing consensus pathways, and ultimately improving care.

OBJECTIVES

We sought to determine current international clinical practices in the investigation, registration, and treatment of people with BDUC internationally.

METHODS

An online structured survey was conducted of healthcare providers who managed patients with bleeding disorders using the ISTH RedCap tool.

RESULTS

Two hundred sixteen respondents from 39 countries were included in the final analysis. The clinical assessment of those with a possible bleeding disorder varied, with only 55% excluding hypermobility but high levels (80%) of bleeding assessment tool usage. In hemostatic testing, only the prothrombin time and activated partial thromboplastin time tests gained universal support. Tranexamic acid was favored for prophylaxis for minor (71%)/major (59%) surgeries and pregnancy (58%), but advice on the treatment if bleeding occurred was heterogeneous. The management of heavy menstrual bleeding in women despite combined oral contraceptive pill use also proved challenging, with healthcare providers selecting multiple alternative strategies.

CONCLUSION

Significant variation exists in the recognition, registration, and management of people with BDUC worldwide. This survey emphasizes the need for consensus pathways to diagnose and treat BDUC to standardize and improve care for patients internationally.