Treatment of von Willebrand's Disease

Macrocyclic-based strategy in drug design: From lab to the clinic

Macrocyclic compounds have emerged as potent tools in the field of drug design, offering unique advantages for enhancing molecular recognition, improving pharmacokinetic properties, and expanding the chemical space accessible to medicinal chemists. This review delves into the evolutionary trajectory of macrocyclic-based strategies, tracing their journey from laboratory innovations to clinical applications. Beginning with an exploration of the defining structural features of macrocycles and their impact on drug-like characteristics, this discussion progresses to highlight key design principles that have facilitated the development of diverse macrocyclic drug candidates. Through a series of illustrative representative case studies from approved macrocyclic drugs and candidates spanning various therapeutic areas, particular emphasis is placed on their efficacy in targeting challenging protein-protein interactions, enzymes, and receptors. Additionally, this review thoroughly examines how macrocycles effectively address critical issues such as metabolic stability, oral bioavailability and selectivity. Valuable insights into optimization strategies employed during both approved and clinical phases underscore successful translation of promising leads into efficacious therapies while providing valuable perspectives on harnessing the full potential of macrocycles in drug discovery and development endeavors.

Critical hematological parameters in bleeding during extracorporeal membrane oxygenation support

Bleeding complications are frequently observed in patients undergoing extracorporeal membrane oxygenation and are associated with increased mortality. Due to the complex mechanisms, managing bleeding during ECMO remains a challenge. Acquired von Willebrand syndrome (AVWS) in ECMO highlights a potentially reduced affinity of von Willebrand factor (vWF) for binding to platelets and collagen in response to vascular damage, thus contributing to increased bleeding in ECMO patients. Conventional coagulation parameters are incomplete predictors for bleeding in ECMO patients, whereas AVWS is often overlooked due to the absence of vWF evaluation in the coagulation profile. Therefore, clinical physicians should evaluate AVWS in patients experiencing bleeding complications during ECMO support.

Factor VIII stimulants and other novel therapies for the treatment of von Willebrand disease: what's new on the horizon?

INTRODUCTION

Von Willebrand disease (VWD) is the most common inherited bleeding disorder, affecting about 0.6% to 1.3% of the population, and is characterized primarily by mucocutaneous bleeding secondary to defective platelet adhesion and aggregation. Current therapeutic options for those with severe disease are limited and require frequent intravenous infusions.

AREAS COVERED

This review discusses the current and recently completed clinical trials involving pathways to FVIII augmentation for the treatment of VWD. Clinical trials registered on clinicaltrials.gov and published data via PubMed searches through June 2024 were included.

EXPERT OPINION

Available treatment options to those with VWD are limited in part due to limited clinical trials, the complexity of VWD types, and the pharmacokinetics of current treatment options. The development of therapeutic options that reduce treatment burden is necessary to improve quality of life and reduce bleeding complications and in recent years there has been an increased interest from industry to apply novel therapeutics for VWD. The FVIII mimetic, emicizumab, has demonstrated early success in patients with severe VWD and is a promising treatment option for those who require prophylaxis. Furthermore, products like efanesoctocog alfa (Altuviiio®) and BT200 have achieved enhanced VWF/FVIII half-life extension could expand the current treatment landscape while concurrently minimizing treatment burden.

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.

Strategies to prevent blood loss and reduce transfusion in emergency general surgery, WSES-AAST consensus paper

Emergency general surgeons often provide care to severely ill patients requiring surgical interventions and intensive support. One of the primary drivers of morbidity and mortality is perioperative bleeding. In general, when addressing life threatening haemorrhage, blood transfusion can become an essential part of overall resuscitation. However, under all circumstances, indications for blood transfusion must be accurately evaluated. When patients decline blood transfusions, regardless of the reason, surgeons should aim to provide optimal care and respect and accommodate each patient's values and target the best outcome possible given the patient's desires and his/her clinical condition. The aim of this position paper was to perform a review of the existing literature and to provide comprehensive recommendations on organizational, surgical, anaesthetic, and haemostatic strategies that can be used to provide optimal peri-operative blood management, reduce, or avoid blood transfusions and ultimately improve patient outcomes.

Efficacy of a 1:1 ratio VWF/FVIII concentrate in patients with von Willebrand disease

INTRODUCTION

Patients with von Willebrand disease (VWD) require administration of von Willebrand factor (VWF) concentrates peri-operatively. Concerns about FVIII accumulation after repetitive injections of a 1:1 ratio VWF/FVIII clotting factor concentrate (CFC) led this study to explore the recovery and FVIII accumulation over time.

METHODS

This monocentre study examined patients with VWD receiving perioperative 1:1 ratio CFC infusions. CFC dosing was based on body weight and endogenous VWF/FVIII activity. FVIII and VWF activity was monitored at T0 (baseline), T1 (15 min postinfusion), and trough levels at T2-T6 (24-120 h).

RESULTS

We included 125 patients, undergoing 125 procedures (63 major surgeries, 62 minor), with a median of two CFC infusions (IQR 1-3). With a mean administered dose of 35.7 IU/kg CFC, recovery rates of FVIII and VWF were 2.6 IU/dL per IU/kg and 2.4 IU/dL per IU/kg, respectively. Mean FVIII levels at T0 were 62 (SD 51.9), T1: 164 (SD 80.4), T2: 155 (SD 62.8), T3: 162 (SD 59.8), T4: 124 (SD 78.4), and T5: 120 (SD 65.3) IU/dL. Mean VWF activity levels at T0 were 29 (SD 25.0), T1: 133 (SD 43.7), T2: 92 (SD 37.2), and T3: 86 (SD 37.5) IU/dL. Subgroup analysis in 47 patients with more than three infusions, showed no accumulation of mean FVIII levels.

CONCLUSION

This perioperative study demonstrated excellent FVIII and VWF recovery of a 1:1 ratio VWF product in patients with VWD. Stable FVIII and VWF activity levels were observed after repeated infusions, without accumulation. Most major surgeries required only three CFC infusions.

Thrombocytopenia and Bleeding in Chronic Kidney Disease: A Case of Acquired Von Willebrand Syndrome

Acquired von Willebrand disease is a rare condition with laboratory findings similar to the inherited type, which can be autosomal dominant or recessive. This case describes a rather rare clinical situation of a 65-year-old man with stage 4 chronic kidney disease who also had acquired von Willebrand syndrome (AvWS) with thrombocytopenia and bleeding. The patient had a complaint of easy fatigability, easy bruising, and prolonged bleeding from small cuts. The patient's initial laboratory workup included thrombocytopenia, which on further evaluation established the diagnosis of AvWS due to chronic kidney disease. More specific examination revealed reduced activity of the von Willebrand factor. The patient was managed with desmopressin and von Willebrand factor concentrates and there was a transient rise in platelet count and relief of symptoms of bleeding. This case underlines the importance of AvWS in any differential diagnosis of thrombocytopenia in patients with chronic kidney disease. This report aims to provide recommendations for early identification and management of AvWS to improve the outcome.

Tranexamic Acid: An Evergreen Hemostatic Agent

Tranexamic acid (TXA) is an important antifibrinolytic agent, which inhibits plasminogen activation and fibrinolysis. Several controlled randomized trials have investigated the role of TXA in preventing or decreasing blood loss across different surgical interventions or medical conditions characterized by excessive bleeding, consistently documenting its effectiveness and safety. Although the first clinical use of TXA dates back to more than 60 years ago, TXA remains the focus of intense research. This narrative review summarizes the more recent results and indications on the clinical use of TXA.

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.

Orthognathic Surgery in Patients With Von Willebrand's Disease: A Report of Four Cases and Literature Review

Von Willebrand's disease (VWD), characterized by quantitatively or qualitatively abnormal von Willebrand factor (VWF), is the most common inherited bleeding disorder. There is limited evidence of treatment using orthognathic surgery in patients with VWD. This report focuses on four patients with VWD who underwent orthognathic surgery and received Factor VIII/VWF concentrates (Confact F) preoperatively. One patient with type 3 (severe) VWD underwent delayed extubation owing to laryngeal edema and exhibited epistaxis thereafter. No perioperative complications were observed in any of the other patients. Two of the four patients were diagnosed with VWD during preoperative screening. Most young adults do not experience general anesthesia and, therefore, may not have undergone blood tests at a hospital. Thus, preoperative screening and adoption of a multidisciplinary approach to orthognathic surgery is important in patients with bleeding disorders such as VWD. Close communication between anesthetists, surgeons, and hematologists is essential to ensure effective management during the perioperative period.

Abdominoplasty in a Patient With Type 3 von Willebrand Disease: A Case Report

ABSTRACT

von Willebrand disease (vWD) is an inherited bleeding disorder that is characterized by a quantitative or qualitative deficiency of the von Willebrand factor (vWF). Type 3 is the most severe form of vWD with a near-complete absence of vWF and a significantly increased risk of excessive bleeding and hematoma during a surgical procedure. To date, no data on surgical and hemostatic management of a type 3 vWD patient undergoing body-contouring surgery has been published. We report the case of a 47-year-old woman with type 3 vWD requiring medically indicated abdominoplasty after massive weight loss due to bariatric surgery. The case was successfully managed with individualized bodyweight-adapted substitution of recombinant vWF vonicog alfa and tranexamic acid under close monitoring of vWF and factor VIII activity. For further risk stratification, we propose the multidisciplinary treatment of patients with severe vWF undergoing elective plastic surgery in specialized centers providing around-the-clock laboratory testing and access to a blood bank. In addition, strict hemostasis during surgery and early postoperative mobilization with fitted compression garments are recommended to further reduce the risk of bleeding and thromboembolic complications.

In vitro field study and worldwide survey assessing how clinical haemostasis laboratories analyse recombinant and plasma-derived von Willebrand factor products

INTRODUCTION

Several well-established clinical laboratory methods are available to measure von Willebrand factor (VWF) in plasma samples, but few data are available on their use for analysing recombinant VWF (rVWF).

AIM

To evaluate how clinical diagnostic laboratories analyse rVWF and plasma-derived VWF (pdVWF) spiked in vitro into VWF-deficient plasma using quantitative protein and functional assays of VWF.

METHODS

Human VWF-deficient plasma samples were spiked with rVWF (vonicog alfa; Takeda) or pdVWF/factor VIII (pdVWF/FVIII; antihemophilic factor/VWF complex [human], CSL Behring), each at final concentrations of 1.0, 0.6, 0.2, 0.1 IU/mL VWF:ristocetin cofactor activity (VWF:RCo) according to labelled VWF activity. The ISTH SSC secondary coagulation standard was used as a control. Participating laboratories received three sets of these blinded aliquots. Mean results per assay were compared with the expected potency based on the labelled VWF:RCo activity.

RESULTS

Among 39 laboratories, the most commonly established assay was VWF:RCo; 22 laboratories reported data from 2214 tests. Despite a trend to lower values, VWF:RCo activities for rVWF were in agreement with target concentrations (71%-109%), whereas VWF:platelet glycoprotein Ib (VWF:GpIb) and VWF collagen-binding activity (VWF:CB) assays gave high recoveries (up to 132% and 127%, respectively). In contrast, pdVWF/FVIII was substantially underestimated by VWF:GpIb and VWF:CB assays (56%-86% recoveries), whereas the VWF:RCo assay gave recoveries of 47%-112% for pdVWF/FVIII.

CONCLUSION

The results of VWF assays used in clinical laboratories differ between rVWF and pdVWF, particularly for VWF:GpIb and VWF:CB assays. These differences may arise from the higher multimeric structure of rVWF compared to pdVWF.

Long-term follow-up of patients with congenital thrombotic thrombocytopenia purpura receiving a plasma-derived factor VIII (Koate) that contains ADAMTS13

BACKGROUND

Hereditary thrombotic thrombocytopenia purpura (hTTP) is an ultra-rare disorder resulting from an inherited deficiency of ADAMTS13, a von Willebrand factor (VWF)-cleaving metalloprotease. The plasma-derived factor VIII/VWF Koate (FVIII/VWFKoate ) has been shown to contain ADAMTS13, allowing for its use to treat hTTP at home by the patient/caregiver.

AIM

Based on prior demonstration of safe and effective use of FVIII/VWFKoate in eight patients with hTTP, we conducted a retrospective study to gather additional data regarding the use of FVIII/VWFKoate for hTTP.

METHODS

This was a multicentre, retrospective, noninterventional chart review of patients who had received FVIII/VWFKoate for the management of hTTP. Data collected included demographics, medical history, relevant family history, past use and tolerability of fresh frozen plasma, and details regarding FVIII/VWFKoate therapy.

RESULTS

The cohort included 11 patients (seven males, four females) with hTTP, ranging in age at study entry from 2 to 28 years. The average duration of FVIII/VWFKoate therapy was 4.8 years (range, 0.5-6.5 years). Among nine patients using FVIII/VWFKoate as prophylaxis, the normalized annual rate of breakthrough TTP episodes ranged from 0.2 to 1.1 episodes/year. All nine patients who received FVIII/VWFKoate prophylaxis had thrombocytopenia recorded at baseline, while eight (88.9%) did not have thrombocytopenia after using FVIII/VWFKoate . There was one AE (unspecified) attributed to FVIII/VWFKoate .

CONCLUSION

These data suggest that FVIII/VWFKoate is a safe and well-tolerated source of the missing ADAMTS13 enzyme in patients with hTTP, producing a marked reduction in thrombocytopenia prevalence, low frequency of TTP episodes, and with the added benefit of self- or caregiver-administration.

Coarse-grained simulations of von Willebrand factor adsorption to collagen with consequent platelet recruitment

A multimeric glycoprotein of blood plasma-Von Willebrand factor (VWF)-mediates platelet adhesion to the fibrillar collagen of the subendothelial matrix if the blood vessel walls are damaged. The adsorption of VWF to collagen is thus essential for the initial stages of platelet hemostasis and thrombosis, as it plays a role of a molecular bridge between the injury and platelet adhesion receptors. Biomechanical complexity and sensitivity to the hydrodynamics are inherent in this system, therefore, modern computational methods supplement experimental studies of biophysical and molecular mechanisms that underlie platelet adhesion and aggregation in the blood flow. In the present paper, we propose a simulation framework for the VWF-mediated platelet adhesion to a plane wall with immobilized binding sites for VWF under the action of shear flow. VWF multimers and platelets are represented in the model by particles connected by elastic bonds and immersed in a viscous continuum fluid. This work complements the scientific field by taking into account the shape of a flattened platelet, but keeping a compromise between the detail of the description and the computational complexity of the model.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Patient-centered care in von Willebrand disease: are we there yet?

INTRODUCTION

Von Willebrand Disease is the most common inherited bleeding disorder. Paradoxically, affected individuals are often misdiagnosed and experience substantial diagnostic delay. There are sex-specific health disparities in VWD rooted in the stigmatization of vaginal bleeding, which leads to symptom dismissal, lack of timely access to care and lower health-related quality of life.

AREAS COVERED

Following the core elements of patient-centered care - respect for patient preferences, values, and needs, we describe the current state of VWD care. Challenges of diagnostic delay, serial misrecognition of abnormal bleeding, and symptom dismissal are barriers that disproportionately affect women with VWD. These negative effects are further amplified in individuals living in low- and middle-income countries. We describe the importance of coordinated multidisciplinary care, as well as the need for patient education and empowered self-advocacy.

EXPERT OPINION

While tremendous work has been done to improve the diagnosis and management of VWD, timely and high-quality research is urgently needed to address care gaps. Systemic changes such as resource investment, dedicated research funding for novel treatment modalities, and effective knowledge translation strategies to address structural barriers are needed to facilitate effective patient-centered care for VWD.

Pharmacokinetic-Pharmacodynamic Comparison of Recombinant and Plasma-Derived von Willebrand Factor in Patients with von Willebrand Disease Type 3

Background

Recombinant von Willebrand factor (rVWF, vonicog alfa, Vonvendi/Veyvondi, Takeda Pharmaceuticals USA, Lexington, MA) and several plasma-derived VWF/factor VIII (pdVWF/FVIII) concentrates are available for treating bleeding episodes in patients with von Willebrand disease (VWD).

Purpose

To develop population pharmacokinetic (PK)/pharmacodynamic (PD) models that describe VWF:ristocetin cofactor (VWF:RCo) activity and its relationship with FVIII activity (FVIII:C) over time following intravenous administration of either rVWF or a pdVWF/FVIII concentrate (VWF:RCo/FVIII:C 2.4:1) in patients with VWD; to use the final PK/PD models for an in silico comparison of rVWF and pdVWF/FVIII.

Methods

The population PK model for rVWF was based on data from four clinical studies in which rVWF was administered to adult patients with VWD type 1, 2 or 3 (phase 1: NCT00816660; phase 3: NCT01410227 and NCT02283268) or severe hemophilia A (phase 1: EudraCT 2011-004314-42). The PK and PK/PD models for pdVWF/FVIII were based on data from the phase 1 study (NCT00816660) in patients with type 3 VWD who received either rVWF plus recombinant FVIII (rFVIII, octocog alfa, ADVATE^®, Takeda Pharmaceuticals USA, Lexington, MA, USA) or pdVWF/FVIII.

Results

There was a marked difference in clearance following rVWF administration compared with pdVWF/FVIII in type 3 VWD, leading to a ~1.75 longer mean residence time (ie, persistence of VWF:RCo activity in the body) and half-life for rVWF versus pdVWF/FVIII. Simulations showed that following repeated administration of rVWF (50 IU/kg), a FVIII:C activity of >40 IU/dL can be maintained for the full 72 h dosing interval.

Conclusion

The slower elimination of VWF:RCo following rVWF administration results in a prolonged effect on FVIII turnover compared with pdVWF/FVIII administration.

Novel Aspects Targeting Platelets in Atherosclerotic Cardiovascular Disease—A Translational Perspective

Platelets are important cellular targets in cardiovascular disease. Based on insights from basic science, translational approaches and clinical studies, a distinguished anti-platelet drug treatment regimen for cardiovascular patients could be established. Furthermore, platelets are increasingly considered as cells mediating effects “beyond thrombosis”, including vascular inflammation, tissue remodeling and healing of vascular and tissue lesions. This review has its focus on the functions and interactions of platelets with potential translational and clinical relevance. The role of platelets for the development of atherosclerosis and therapeutic modalities for primary and secondary prevention of atherosclerotic disease are addressed. Furthermore, novel therapeutic options for inhibiting platelet function and the use of platelets in regenerative medicine are considered.

Structure and Function of Recombinant versus Plasma-Derived von Willebrand Factor and Impact on Multimer Pharmacokinetics in von Willebrand Disease

BACKGROUND

Recombinant von Willebrand factor (rVWF, vonicog alfa) is a purified VWF concentrate produced from Chinese hamster ovary cells. rVWF is not exposed to the VWF-cleaving protease ADAMTS13 and so is not subject to proteolytic degradation of large (L) and ultra-large (UL) VWF multimers by that enzyme.

PURPOSE

To compare the structure and function of rVWF with the human plasma-derived VWF [pdVWF] concentrates Haemate P®/Humate-P®, Voncento®, Wilate®/Eqwilate®, and Wilfactin®/Willfact®; to investigate the relationship between VWF multimeric pattern and VWF:ristocetin cofactor (VWF:RCo) activity through population pharmacokinetic (PK) modeling in patients with severe von Willebrand disease (VWD) treated with rVWF.

METHODS

Analyses included VWF:RCo activity, VWF:collagen-binding activity, VWF:platelet glycoprotein Ib receptor binding, factor VIII (FVIII) binding capacity, and VWF-mediated platelet adhesion under flow conditions. VWF multimeric structure was determined by agarose gel electrophoresis. Population PK models describing the activity-time profile of small, medium, and L/UL multimers following intravenous administration of rVWF in patients with severe VWD were developed.

RESULTS

Findings demonstrate that rVWF contains a non-degraded VWF multimer pattern including the UL multimers not present in pdVWF concentrates. rVWF displayed higher specific platelet-binding activity, and faster mediation of platelet adhesion to collagen under shear stress versus pdVWF concentrates. rVWF also demonstrated higher FVIII binding capacity than Haemate P®, Voncento® and Wilate®. Modeling provided evidence that VWF:RCo activity in patients with severe VWD treated with rVWF is associated with L/UL VWF multimers in the circulation.

CONCLUSIONS

Findings suggest that the L and UL multimers preserved in rVWF contribute to high biological activity and might be important for providing hemostatic efficacy.

Effect of desmopressin on bleeding during endoscopic sinus surgery: A randomized clinical trial

Background

This study aimed to evaluate the effect of local nasal desmopressin premedication on blood loss and the quality of surgical field in Functional Endoscopic Sinus Surgery (FESS).

Material and methods

In a randomized clinical trial, patients referred for FESS to treat their bilateral chronic rhinosinusitis were recruited. The participants were adults (≥18 years). They were randomly assigned (1:1:1) to receive low-dose (20 μg) or high-dose (40 μg) intranasal desmopressin (DDAVP) or placebo 60 min before the induction of general anesthesia. Standard FESS was performed by the same surgeon. The primary outcomes were volume of intraoperative bleeding and the quality of surgical field. Clean surgical field was defined as a score ≤2 on the Boezaart grading system.

Results

A total of 120 patients were included on an intention-to-treat basis (mean age: 41.0 years; 40 women, 80 men). There were no significant differences in primary outcomes between low-dose DDAVP and placebo. As for the volume of blood loss, however, there was a significant difference between high-dose DDAVP and placebo (mean difference: 29.6 ml; adjusted Cohen's d: -1.02; p < .001). Also, in the high-dose DDAVP, the probability of having a good surgical field over time was about two times higher than in the placebo group (RRs for first and second surgical sides: 1.89 and 2.18). The number needed to treat for the two time points was 1.6 and 1.3, respectively.

Conclusion

The present study showed that the use of desmopressin at a dose of 40 μg 1 h before surgery can reduce bleeding and improve the quality of the surgical field. Further studies are recommended to be able to generalize these findings to other ENT surgeries.

Level of evidence

1b.

Recent advances in therapeutic options for rare hemostatic disorders: selected poster extracts of recent research in hemophilia A, congenital hemophilia with inhibitors, von Willebrand disease, and thrombotic thrombocytopenic purpura presented at the 29th congress of the International Society on Thrombosis and Haemostasis (ISTH 2021, Jul 17-21; virtual congress)

Hemophilia, von Willebrand disease (VWD), and thrombotic thrombocytopenic purpura (TTP) are rare diseases affecting normal hemostasis. Although they differ in their pathogenesis and clinical manifestation, if left undiagnosed and untreated, all these conditions can result in severe long-term consequences and can be potentially life-threatening. This article summarizes a poster series funded by Takeda and presented virtually at the 29th annual congress of the International Society on Thrombosis and Haemostasis (ISTH) in 2021: Data from real-world evidence highlight the importance of joint health and personalized prophylaxis to prevent bleeding for patients with hemophilia, the need to further raise disease awareness in support of timely diagnosis and access to treatment in general practice settings for patients with VWD, and describe the clinical burden for patients with TTP and the importance to advance treatment options for these patients.

Gastrointestinal Bleeding in Congenital Bleeding Disorders

Gastrointestinal bleeding (GIB) is serious, intractable, and potentially life-threatening condition. There is considerable heterogeneity in GIB phenotypes among congenital bleeding disorders (CBDs), making GIB difficult to manage. Although GIB is rarely encountered in CBDs, its severity in some patients makes the need for a comprehensive and precise assessment of underlying factors and management approaches imperative. Initial evaluation of GIB begins with assessment of hematological status; GIB should be ruled out in patients with chronic anemia, and in presentations that include hematemesis, hematochezia, or melena. High-risk patients with recurrent GIB require urgent interventions such as replacement therapy for treatment of coagulation factor deficiency (CFD). However, the best management strategy for CFD-related bleeding remains controversial. While several investigations have identified CBDs as potential risk factors for GIB, research has focused on assessing the risks for individual factor deficiencies and other CBDs. This review highlights recent findings on the prevalence, management strategies, and alternative therapies of GIB related to CFDs, and platelet disorders.

Cardiac Surgery in Patients With Blood Disorders

Blood disorders that can contribute to abnormal bleeding can have a detrimental effect during cardiac surgery. Patients who are known to have such pathologies should be investigated thoroughly and cautious measures would need to be taken when cardiac surgery is needed in this cohort. The majority of current literature for cardiac surgery in patients with von Willebrand Disease and haemophilia are case reports. Nevertheless, evidence shows that optimising factor levels pre, intra and postoperatively offers outcomes similar to that of patients without these disorders. Preoperative screening followed by appropriate iron therapy reduces mortality for patients with anaemia. In this group, haemoglobin levels can be improved postoperatively through iron supplementation. The management strategy of cardiac surgery for people with blood disorders requires a multidisciplinary approach that is highly individualised for each patient. It is essential to adequately adjust preoperative, perioperative and postoperative care to the patient's blood disorder in order to achieve outcomes similar to that of patients without blood disorders.

Directed Donation: Special Considerations and Review for Contemporary Clinical Practices

Background: Directed blood donation is defined as the donation of blood or its components for the purpose of transfusion into a specified individual. Directed blood donation holds historic significance, and although practices as of 2021 encourage voluntary, nonrenumerated blood donations, public interest in directed donation remains. Requests to discuss the risks and benefits of directed donations are a common inquiry for transfusion medicine, transplant, and hematology/oncology professionals. This narrative review discusses the history of directed donation and summarizes directed donation considerations in the context of modern transfusion practices. Methods: We conducted a systematic search of PubMed for published literature on the topic of directed blood donation and gathered information about its benefits and potential harms with respect to the variety of products used in transfusion medicine. Results: The drawbacks of directed donation include transfusion-transmitted infection risk, alloimmunization risk, increased transfusion-associated graft vs host disease risk, decreased expediency in treatment, and increased administrative burdens. However, a role remains for directed blood donation in specific patient populations, such as individuals with rare blood types or immunoglobulin A deficiencies, because of the difficulties in finding compatible blood for transfusion. Conclusion: Clinicians should consider the risks and benefits when discussing directed blood donations with patients and family members.

Addressing unmet needs in rare bleeding disorders: selected poster extracts of recent research in hemophilia A and von Willebrand disease presented at the 14th Annual Congress of the European Association for Haemophilia and Allied Disorders (EAHAD) (Feb 3-5, 2021; virtual congress)

Hemophilia A and von Willebrand disease (VWD) are inherited rare bleeding disorders affecting normal hemostasis. Patients with VWD, especially those with severe disease types, share some similarities to patients with hemophilia A in their burden of disease: they suffer from an increased risk of potentially severe and life-threatening bleeds and associated long-term consequences, such as impaired joint health and overall lower quality of life. However, the two bleeding disorders differ in their primary cause and affected patient population, and comprise a range of different bleeding phenotypes with varying unmet needs. Generating scientific evidence to advance health care for patients with rare bleeding disorders is challenging due to the low prevalence and heterogeneity of affected populations, including patient demographics and symptom severities. Innovative study designs are needed to adequately answer relevant scientific questions and address patients' unmet needs. In support of advancing clinical outcomes and treatment options for these patients, at the recent EAHAD 2021 annual congress, novel approaches and data from clinical and real-world observational studies, as well as systematic literature analyses, were presented. Herein, extracts from seven selected posters reporting research in hemophilia A and VWD funded by Takeda are discussed.

Management of large volume liposuction in lipedema patients with von Willebrand disease: A systematic review and treatment algorithm

BACKGROUND

When performing large volume liposuction, perioperative management of lipedema patients with coagulation disorders remains challenging due to a lack of clinical experience. With a prevalence of 1% of von Willebrand disease (VWD) in the general population, basic knowledge on diagnostic and adapted surgical strategies are essential for patients' safety.

OBJECTIVE

Based on a selective literature review, the purpose of this article is to present a standardized algorithm for diagnosis and perioperative treatment of VWD patients undergoing large volume liposuction.

METHODS

The databases MEDLINE (via PubMed) and Web of Science were selectively searched with the term "(((liposuction) OR (surgery)) OR (lipectomy)) AND (((VWD) OR (hemostaseology)) OR (von Willebrand disease))". Included were articles published in English or German until November 2020.

RESULTS

The evidence for large volume liposuctions in patients with VWD is limited. Experience is largely based on operations with similar bleeding risks. A safe performance requires an adjustment of the surgical technique and a customized perioperative drug substitution plan. According to the current literature, perioperative thromboembolic events appear to be rare with adequate drug treatment.

CONCLUSION

The implementation of the developed diagnostic and treatment algorithm may help further reducing bleeding complications and improve the safety for treated patients.

Desmopressin nasal spray reduces blood loss and improves the quality of the surgical field during functional endoscopic sinus surgery

Background and Aims

Making a dry surgical field during functional endoscopic sinus surgery (FESS) is a challenge for anesthetists. This study was conducted to evaluate the pre-emptive hemostatic effects of a single dose of an intranasal spray of desmopressin (DDAVP) in sinus surgery.

Material and Methods

Sixty consecutive patient's as first-time candidates for FESS due to chronic sinusitis were enrolled. They were randomly allocated to receive either a nasal spray of DDAVP 20 μg or sterile water before induction of anesthesia. Management of anesthesia was achieved with propofol and remifentanil infusions. Blood loss, quality of the surgical field, and surgeon's satisfaction were compared between the two groups.

Results

Blood loss in the DDAVP group was 147 ± 43 mL and in the placebo group 212 ± 64 mL (mean ± SD, P < 0.01). The quality of the surgical field in the DDAVP group was better than the placebo group. (median score, 1 (1-2) vs. 2 (1-3), P = 0.017). Surgeons were more satisfied with the surgical field in the DDAVP group than in the control group (median score, 4 (2.8-5) vs. 3 (2-3), P = 0.04).

Conclusion

Premedication with nasal spray DDAVP 20 μg effectively reduces bleeding and improves the surgical field during FESS.

Population pharmacokinetics of the von Willebrand factor-factor VIII interaction in patients with von Willebrand disease

Recent studies have reported that patients with von Willebrand disease treated perioperatively with a von Willebrand factor (VWF)/factor VIII (FVIII) concentrate with a ratio of 2.4:1 (Humate P/Haemate P) often present with VWF and/or FVIII levels outside of prespecified target levels necessary to prevent bleeding. Pharmacokinetic (PK)-guided dosing may resolve this problem. As clinical guidelines increasingly recommend aiming for certain target levels of both VWF and FVIII, application of an integrated population PK model describing both VWF activity (VWF:Act) and FVIII levels may improve dosing and quality of care. In total, 695 VWF:Act and 894 FVIII level measurements from 118 patients (174 surgeries) who were treated perioperatively with the VWF/FVIII concentrate were used to develop this population PK model using nonlinear mixed-effects modeling. VWF:Act and FVIII levels were analyzed simultaneously using a turnover model. The protective effect of VWF:Act on FVIII clearance was described with an inhibitory maximum effect function. An average perioperative VWF:Act level of 1.23 IU/mL decreased FVIII clearance from 460 mL/h to 264 mL/h, and increased FVIII half-life from 6.6 to 11.4 hours. Clearly, in the presence of VWF, FVIII clearance decreased with a concomitant increase of FVIII half-life, clarifying the higher FVIII levels observed after repetitive dosing with this concentrate. VWF:Act and FVIII levels during perioperative treatment were described adequately by this newly developed integrated population PK model. Clinical application of this model may facilitate more accurate targeting of VWF:Act and FVIII levels during perioperative treatment with this specific VWF/FVIII concentrate (Humate P/Haemate P).

Anesthetic Management of Von Willebrand Disease in Pregnancy: A Retrospective Analysis of a Large Case Series

BACKGROUND

Although Von Willebrand disease (vWD) is the most common heritable bleeding disorder, there are limited reports regarding the safety of neuraxial anesthesia in the obstetric population and no definitive guidelines specifying recommended pretreatment or therapies for patients with vWD. The aim of this study is to describe the anesthetic management of pregnant patients with vWD at a large tertiary-care center.

METHODS

In this retrospective analysis, the study population was identified from vWD patients evaluated by our high-risk obstetric anesthesia consultation service and by diagnosis codes from our institutional research database registry. We manually reviewed records of patients with vWD in pregnancy who delivered at our institution between January 1, 2000 and January 1, 2019 for demographic characteristics, circumstances of vWD diagnosis, history of bleeding, laboratory studies, and overall management of vWD. Anesthetic management of vWD was at the discretion of individual providers, based on multidisciplinary consensus and the specific circumstances of each patient's disease and obstetric presentation.

RESULTS

We identified 106 deliveries among 71 individual vWD patients. Of the unique patients, 54 had vWD type 1, 6 had vWD type 2, and 11 had vWD type unknown. Forty-three cases (40.6%) were cesarean deliveries. Neuraxial techniques were used in 94 of 106 deliveries (88.7%). Treatment with desmopressin or Von Willebrand factor/factor VIII concentrate before neuraxial anesthesia occurred in 27 of 94 neuraxial anesthetics (28.7%). Eleven deliveries (10.4%) were complicated by postpartum hemorrhage (PPH), defined as estimated blood loss of ≥1000 mL. There were no noted adverse anesthetic outcomes (0 of 106; 0% [95% confidence interval, 0-3.4]), including neuraxial hematoma or thromboembolic events.

CONCLUSIONS

In this large case series, the majority of vWD patients received neuraxial anesthesia for labor and delivery, with no noted adverse events. This suggests that neuraxial anesthesia can be safely performed with the peripartum management that we describe. Pretreatment was dictated by the type and severity of vWD. Multidisciplinary planning is important to optimize the coagulation status of patients with vWD and facilitate options for analgesia and anesthesia.

Type 3 von Willebrand Disease in Pregnancy: A Systematic Literature Review

OBJECTIVE

von Willebrand disease (VWD) is a hereditary bleeding disorder. Type 3 VWD is the most severe and rare phenotype that presents many challenges for management of pregnant women. The aim of this study was to review the maternal characteristics and complications in pregnant women with Type 3 VWD.

STUDY DESIGN

A systematic literature search was performed to include all publications that address Type 3 VWD in pregnancy.

RESULTS

Thirteen studies met the inclusion criteria. There were 28 pregnancies with Type 3 VWD in 17 women. All were diagnosed with Type 3 VWD prior to pregnancy. Concentrate treatment was administered before delivery for 19 pregnancies and postpartum for 26 pregnancies. Eight pregnancies required blood products postpartum. Primary postpartum hemorrhage (PPH) was reported in 48% (10/21) and secondary PPH was reported in 56% (5/9). Secondary PPH occurred between 7 and 22 days. No study reported hysterectomies, intensive care unit admissions, or maternal mortality. All 28 pregnancies resulted in 28 live births at term.

CONCLUSION

Our review highlights the maternal outcomes in patients with Type 3 VWD and the different approaches in management during pregnancy and delivery. Despite prior knowledge of this bleeding disorder, PPH was still a significant complication.

Von Willebrand disease type 2N: An update

Quantitative or qualitative defects of von Willebrand factor (VWF) are responsible for the most common inherited bleeding disorder, von Willebrand disease (VWD). Type 2N VWD is an uncommon recessive disorder that results from gene mutations located in the region coding for the binding site of VWF for factor VIII (FVIII). This narrative review describes the pathophysiology, diagnostic procedures and treatment as well as the molecular biology of type 2N VWD. Although other VWF-dependent functions like binding to platelets and collagen are preserved, FVIII plasma levels are low due to the rapid clearance of this moiety in the absence or reduction of its binding to VWF. The diagnosis of type 2N should be considered in patients with low FVIII coagulant activity (FVIII:C) and disproportionally higher VWF antigen, especially when they present with an autosomal recessive pattern of inheritance. Because an accurate diagnosis is essential for genetic counseling and optimal treatment, type 2N must be distinguished from mild/moderate hemophilia A and its carrier state. This differential diagnosis can be obtained by using the laboratory assay of the FVIII binding capacity of VWF (VWF:FVIIIB) or analysis of the FVIII binding site on the VWF gene.

How I manage pregnancy in carriers of hemophilia and patients with von Willebrand disease

Women with inherited bleeding disorders, including carriers of hemophilia A and B, or with von Willebrand disease, have an increased risk of bleeding during pregnancy and delivery. The unborn child may also be affected by the bleeding disorder for which specific measures have to be considered. This requires a multidisciplinary approach, with a team that includes a hematologist, a pediatric hematologist, a clinical geneticist, an obstetrician-perinatologist, and an anesthesiologist. An optimal approach includes prepregnancy genetic counseling, prenatal diagnostic procedures, and a treatment plan for delivery for both the mother and child. Recent retrospective studies show that even if strict guidelines are followed, these women are still at risk of postpartum bleeding. This occurs even if coagulation factor levels are normalized, either due to the pregnancy-induced rise of factor levels or by infusion of coagulation factor concentrates at the time of delivery. In this article, we describe our current diagnostic and clinical management of pregnancy and delivery in women with inherited bleeding disorders. We also briefly discuss possible interventions to improve the outcome of current strategies by increasing target factor levels during and after delivery.

Efficacy and safety of a recombinant Von Willebrand Factor treatment in patients with inherited Von Willebrand Disease requiring surgical procedures

INTRODUCTION

Von Willebrand Disease is a common inherited haemorrhagic disorder due to a deficiency of Von Willebrand Factor (VWF). In case of surgical procedures in patients who are not responsive or have contraindications to desmopressin, replacement therapy with VWF concentrates is indicated. Until recently, only plasma-derived VWF concentrates were available. A new recombinant VWF (rVWF) concentrate that contains no Factor VIII (FVIII) but a high amount of high molecular weight VWF multimers has been available in France since 2018.

AIM

Describe real-world experience of using rVWF in surgical procedures.

METHODS

Sixty-three surgeries for 55 patients were retrospectively analysed in 7 French haemostasis centres.

RESULTS

During minor surgeries, the median (range) number of infusions was 1 (1-8) with a preoperative loading dose of 35 (19-56) rVWF IU/kg and a total median dose of 37.5 IU (12-288). During major surgeries, the median (range) number of infusions was only 3 (1-14) with a median preoperative loading dose of 36 IU (12-51) rVWF IU/kg, and a total median dose of 108 IU (22-340) rVWF IU/kg. The overall clinical efficacy was qualified as excellent/good in 61 of the procedures (97%), moderate in 1 (1.5%) and poor in 1 (1.5%). There was no accumulation of VWF or FVIII during postoperative monitoring. No thromboembolic events, anti-VWF antibodies or adverse events were reported.

CONCLUSION

This French 'real-world' experience shows that a few infusions and low doses of rVWF provided effective prevention of bleeding in major and minor surgeries in inherited VWD, with no clinically significant safety concerns.

Peripartum management of a parturient with type 1C (clearance) von Willebrand disease

Peripartum replacement of factor VIII and von Willebrand factor is not usually required in type 1 von Willebrand disease, as the levels of endogenous factors tend to increase to within the normal range as a physiological change of pregnancy. However, there is wide heterogeneity of genotypes and phenotypes associated with type 1 von Willebrand disease. Here, we describe the anesthetic management of a parturient with type 1C von Willebrand disease, a subtype characterized by decreased plasma von Willebrand factor survival.

Low von Willebrand factor in pediatric patients: Retrospective analysis of 293 cases informs diagnostic and therapeutic decision making

Low von Willebrand factor (VWF) poses diagnostic and therapeutic challenges for predicting bleed risk and need for empiric hemostatic therapy, particularly in children. Retrospective review identified 293 low VWF pediatric patients and investigated clinical and laboratory features. Low activity to antigen ratio was observed in 142 patients. When evaluation included VWF activity with gain-of-function glycoprotein Ib fragments (VWF:GPIbM) assay or VWF exon 28 sequencing, low VW was excluded in the majority (62%) of these patients. Application of a condensed bleeding assessment tool to quantify bleeding symptoms and use of the VWF:GPIbM assay may reduce the number of patients with bleed risk anxiety and unnecessary hemostatic management plans.

New therapies for von Willebrand disease

The management of von Willebrand disease (VWD) is based upon the dual correction of the primary hemostasis defect, due to the inherited deficiency of von Willebrand factor (VWF), and of the secondary defect of factor VIII coagulant activity (FVIII:C), due to the loss of binding and stabilization by VWF of this intrinsic coagulation factor in flowing blood. The traditional therapeutic weapons (the synthetic derivative of the antidiuretic hormone desmopressin and plasma-derived VWF/FVIII concentrates) are able to transiently correct both the defects. With the goal of tackling the primary deficiency in the disease, that is, VWF, but at the same time exploiting the normal capacity of patients to produce FVIII, the novel approach of replacing only VWF was implemented in the last 10 years. Following the manufacturing of a concentrate fractionated from human plasma and of one obtained by recombinant DNA technology, clinical studies have shown that VWF-only products correct not only the primary VWF deficiency but also the secondary FVIII:C deficiency. The demonstrated efficacy of these products in various clinical situations and, ultimately, in such a hemostasis-challenging context as surgery testifies to the effectiveness and safety of this approach. It remains to be seen whether VWF-only products are efficacious and safe in still-unexplored situations, such as use in children; the long-term use for prophylaxis; and in recurrent gastrointestinal (GI) bleeding due to angiodysplasia, a major therapeutic problem in VWD.

Dental extraction in a patient with undiagnosed Von Willebrand's Disease: a case report

Dental extractions are a common part of general dental practice. While dentists routinely screen for medical contraindications during the preoperative assessment, undiagnosed coagulopathies have the potential to severely complicate a seemingly routine extraction. We report a case of surgical removal of a mandibular third molar in a patient with undiagnosed Von Willebrand Disease.

Management of von Willebrand disease with a factor VIII-poor von Willebrand factor concentrate: Results from a prospective observational post-marketing study

BACKGROUND

A triple-secured plasma-derived von Willebrand factor (pdVWF) almost devoid of factor VIII (FVIII):WILFACTIN® , was approved in France in 2003, and then in other countries for the treatment of patients with von Willebrand disease (VWD).

OBJECTIVE

To investigate long-term safety and efficacy of the product in real-life over the first 5 post-approval years.

PATIENTS/METHODS

This prospective, observational, national post-marketing study (PMS) enrolled patients of all ages and VWD types. Patients were observed for up to 3 years and treated for one or more occasions. Efficacy was assessed for each major event. Breakthrough bleeding rate 3 days post-infusion and annualized bleeding rate (ABR) were also evaluated for long-term prophylaxis.

RESULTS

Overall, 155 of 174 patients enrolled from 31 centers were eligible for efficacy assessment. Most patients (76.8%) were severely affected (VWF:RCo ≤ 15 IU/dL). They were treated for 743 bleeds and 140 surgeries including childbirth. Efficacy outcomes were excellent/good for 98.2% of 56 major surgeries and 94.0% of 67 major bleeds. Approximately 75% of 49 major mucosal bleeds were effectively managed without FVIII co-administration. In 32 patients receiving prophylaxis, breakthrough bleeding occurred in 1.5% of infusions and median ABR was 1.0 for 20 patients treated ≥ 12 months. Excellent tolerability was confirmed with no safety concerns. No thrombotic events were observed.

CONCLUSIONS

Results from this PMS increase the clinical experience of a FVIII-poor pdVWF in patients of all ages and VWD types including those with thrombotic risk factors and emphasize that giving FVIII is not always mandatory to effectively treat patients with severe VWD.

Strategies to minimize intraoperative blood loss during major surgery

Background

Reducing operative blood loss improves patient outcomes and reduces healthcare costs. The aim of this article was to review current surgical, anaesthetic and haemostatic intraoperative blood conservation strategies.

Methods

This narrative review was based on a literature search of relevant databases up to 31 July 2019 for publications relevant to reducing blood loss in the surgical patient.

Results

Interventions can begin early in the preoperative phase through identification of patients at high risk of bleeding. Directly acting anticoagulants can be stopped 48 h before most surgery in the presence of normal renal function. Aspirin can be continued for most procedures. Intraoperative cell salvage is recommended when anticipated blood loss is greater than 500 ml and this can be continued after surgery in certain situations. Tranexamic acid is safe, cheap and effective, and routine administration is recommended when anticipated blood loss is high. However, the optimal dose, timing and route of administration remain unclear. The use of topical agents, tourniquet and drains remains at the discretion of the surgeon. Anaesthetic techniques include correct patient positioning, avoidance of hypothermia and regional anaesthesia. Permissive hypotension may be beneficial in selected patients. Promising haemostatic strategies include use of pharmacological agents such as desmopressin, prothrombin complex concentrate and fibrinogen concentrate, and use of viscoelastic haemostatic assays.

Conclusion

Reducing perioperative blood loss requires a multimodal and multidisciplinary approach. Although high-quality evidence exists in certain areas, the overall evidence base for reducing intraoperative blood loss remains limited.

New therapies for von Willebrand disease

The management of von Willebrand disease (VWD) is based upon the dual correction of the primary hemostasis defect, due to the inherited deficiency of von Willebrand factor (VWF), and of the secondary defect of factor VIII coagulant activity (FVIII:C), due to the loss of binding and stabilization by VWF of this intrinsic coagulation factor in flowing blood. The traditional therapeutic weapons (the synthetic derivative of the antidiuretic hormone desmopressin and plasma-derived VWF/FVIII concentrates) are able to transiently correct both the defects. With the goal of tackling the primary deficiency in the disease, that is, VWF, but at the same time exploiting the normal capacity of patients to produce FVIII, the novel approach of replacing only VWF was implemented in the last 10 years. Following the manufacturing of a concentrate fractionated from human plasma and of one obtained by recombinant DNA technology, clinical studies have shown that VWF-only products correct not only the primary VWF deficiency but also the secondary FVIII:C deficiency. The demonstrated efficacy of these products in various clinical situations and, ultimately, in such a hemostasis-challenging context as surgery testifies to the effectiveness and safety of this approach. It remains to be seen whether VWF-only products are efficacious and safe in still-unexplored situations, such as use in children; the long-term use for prophylaxis; and in recurrent gastrointestinal (GI) bleeding due to angiodysplasia, a major therapeutic problem in VWD.

How I manage severe von Willebrand disease

Von Willebrand disease (VWD) is the most common inherited bleeding disorder. Most patients with mild and moderate VWD can be treated effectively with desmopressin. The management of severe VWD patients, mostly affected by type 2 and type 3 disease, can be challenging. In this article we review the current diagnosis and treatment of severe VWD patients. We will also discuss the management of severe VWD patients in specific situations, such as pregnancy, delivery, patients developing alloantibodies against von Willebrand factor and VWD patients with recurrent gastrointestinal bleeding. Moreover, we review emerging treatments that may be applied in future management of patients with severe VWD.