Investigation of von Willebrand factor multimer abnormalities before and after aortic valve replacement using the Hydragel-5 assay.

BACKGROUND: Severe aortic stenosis (sAS) is associated with acquired von Willebrand syndrome (AVWS) by loss of high-molecular-weight multimers (HMWM) of von Willebrand factor (VWF), potentially resulting in perioperative bleeding. Analysis of VWF multimers remains challenging. Recently, the new, rapid Hydragel 5 assay has been developed, using electrophoretic protein separation for dividing VWF-multimers into low (LMWM), intermediate (IMWM), and HMWM, the hemostatically active part of VWF. Here, we evaluated its impact on predicting blood loss in presence of AVWS after surgical aortic valve replacement (SAVR). METHODS: We prospectively examined 52 patients (age: 68 ± 7 years; 54 % male) admitted to SAVR. They were divided in two groups (A: normal VWF, n = 28; B: abnormal VWF, n = 24, defined as VWF-activity/antigen (VWF:Ac/Ag)-ratio < 0.7 and/or HMWM loss). Blood samples and echocardiographic data were collected before, seven days and three months after SAVR. Blood loss and transfusions were recorded. RESULTS: Baseline characteristics and clinical data were similar in both groups. HMWM loss was present in 38.5 % of all patients. HMWM, the VWF:Ac/Ag- and HMWM/(IMWM+LMWM)-ratios were significantly decreased preoperatively in group B but normalized after SAVR. Bleeding, re-thoracotomy and transfusion rates were comparable. HMWM loss was inversely correlated with the peak aortic gradient (Pmax) and positively with the aortic valve area (AVA), while HMWM/(IMWM+LMWM)-ratio negatively correlated with the mean aortic gradient (Pmean). CONCLUSION: HMWM and HMWM/(IMWM+LMWM)-ratio inversely correlate with severity of AS and normalize after SAVR. The Hydragel-5 assay's might be valuable for routine diagnostics to assess bleeding risk and postoperative normalization of AS and VWF abnormalities in SAVR patients.

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

BACKGROUND: Von Willebrand disease type 2N (VWD2N) is usually perceived as a mild bleeding disorder that can be treated by desmopressin (DDAVP). However, VWD2N-patients can be compound heterozygous or homozygous for different variants, p.Arg854Gln (R854Q) being the most frequent causative one. There is limited data about the impact of 2N-variants on VWD2N phenotype and DDAVP-response. OBJECTIVES: To describe the phenotype of VWD2N, including DDAVP-response, according to genotype. PATIENTS/METHODS: VWD2N-patients with a complete genotype/phenotype characterization by the French reference center for VWD, including MCMDM-1VWD bleeding score (BS) were eligible to the study. Results of 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 one 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 to R854QHmz-ones (p<0.001 and p<0.0001 respectively). R854QNeg-patients were diagnosed earlier due to bleeding symptoms and had a higher BS than R854QPos-patients (p<0.001). In DDAVP-trial, FVIII:C survival was lower in VWD type 2N than in type 1. 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.

Haemostatic management of von Willebrand disease during childbirth with a plasma-derived VWF/FVIII concentrate.

BACKGROUND: Females with VWD do not show the same increases in VWF and FVIII levels during pregnancy as females without VWD and are at higher risk of excessive bleeding associated with childbirth. Data on haemostatic management for childbirth in VWD patients are limited. OBJECTIVES: To evaluate the dosing, efficacy and safety of plasma-derived VWF/FVIII (wilate) for prevention of excessive bleeding associated with childbirth in females with any type of VWD. METHODS: Data for females with VWD who received wilate for haemostatic coverage for childbirth during two prospective clinical studies were analysed. RESULTS: Ten females with VWD and a mean age at enrolment of 29.6 years were treated with wilate to prevent excessive bleeding associated with childbirth. Two patients had Type 1, four had Type 2 (two 2A, one 2B and one 2M) and four had Type 3 VWD. Of the ten deliveries, five were by caesarean section. Patients received a mean of 9.5 infusions of wilate over 6.8 exposure days, with a mean total dose of 234 IU/kg per delivery and 25 IU/kg per infusion. Haemostatic management for all deliveries was rated excellent or good, with no excessive bleeding during delivery and no postpartum bleeds during the period of wilate treatment in any patient. Two patients experienced eight possible or probable treatment-related adverse events; all were mild or moderate and resolved. No thromboembolic events were observed. CONCLUSION: The results of this case series indicate that wilate provided effective haemostatic cover for childbirth in females with VWD during delivery and postpartum.

Exploring nonreplacement therapies' impact on hemophilia and other rare bleeding disorders.

The management of hemophilia, von Willebrand disease (VWD), and rare coagulation disorders traditionally relied on replacement therapies, such as factor concentrates, to address clotting factor deficiencies. However, in recent years, the emergence of nonreplacement therapies has shown promise as an adjunctive approach, especially in hemophilia, and also for patients with VWD and rare bleeding disorders. This review article offers an overview of nonreplacement therapies, such as FVIII-mimicking agents and drugs aimed at rebalancing hemostasis by inhibiting natural anticoagulants, particularly in the management of hemophilia. The utilization of nonreplacement therapies in VWD and rare bleeding disorders has recently attracted attention, as evidenced by presentations at the International Society on Thrombosis and Haemostasis 2023 Congress. Nonreplacement therapies provide alternative methods for preventing bleeding episodes and enhancing patients' quality of life, as many of them are administered subcutaneously and allow longer infusion intervals, resulting in improved quality of life and comfort for patients.

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

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

Laparoscopic liver resection for a patient of hepatocellular carcinoma with von Willebrand disease: a case report.

BACKGROUND: The safety of laparoscopic hepatectomy for inherited coagulation disorders is unclear; however, the safety of open hepatectomy has been reported in several studies. Herein, we report the first case of a laparoscopic hepatectomy for a patient with von Willebrand Disease (VWD). CASE PRESENTATION: A 76-year-old male with a history of chronic hepatitis C and VWD type 2B was advised surgical resection of a 4 cm hepatocellular carcinoma in segment 7 of the liver. The patient was diagnosed with VWD in his 40 s due to gastrointestinal bleeding caused by gastric erosion. The von Willebrand factor (VWF) ristocetin cofactor activity was 30%, and VWF large multimer deficiency and increased ristocetin-induced platelet agglutination were observed. The preoperative platelet count was reduced to 3.5 × 104/µL; however, preoperative imaging findings had no evidence of liver cirrhosis, such as any collateral formations and splenomegaly. The indocyanine green retention rate at 15 min was 10%, and his Child-Pugh score was 5 (classification A). Perioperatively, VWF/factor VIII was administered in accordance with our institutional protocol. A laparoscopic partial hepatectomy of the right posterior segment was performed. The most bleeding during surgery occurred during the mobilization of the right lobe of the liver due to inflammatory adhesion between the retroperitoneum and the tumor. Bleeding during parenchymal transection was controlable. The duration of hepatic inflow occlusion was 65 min. The surgical duration was 349 min, and the estimated blood loss was 2150 ml. Four units of red blood cells and fresh frozen plasma were transfused at the initiation of parenchymal transection, and 10 units of platelets were transfused at the end of the parenchymal transection. On postoperative day 1, the transection surface drainage fluid became hemorrhagic, and emergency contrast-enhanced computed tomography showed extravasation in the greater omentum. Percutaneous transcatheter arterial embolization of the omental branch of the right gastroepiploic artery was performed. No further postoperative interventions were required. The patient was discharged on postoperative day 14. CONCLUSION: The indications for laparoscopic hepatectomy in patients with VWD should be carefully considered, and an open approach may still be the standard approach for patients with VWD.

Magnetic resonance imaging-guided focused ultrasound thalamotomy for essential tremor in a patient with von Willebrand disease: perioperative optimization for patients with coagulopathies. Illustrative case.

BACKGROUND: Essential tremor (ET) is one of the most common movement disorders worldwide. In medically refractory ET, deep brain stimulation (DBS) of the ventral intermediate nucleus of the thalamus is the current standard of care. However, DBS carries an inherent 2% to 3% risk of hemorrhage, a risk that can be much higher in patients with concomitant coagulopathy. Magnetic resonance imaging-guided focused ultrasound (MRgFUS) thalamotomy is a surgical alternative that is highly effective in treating ET, with no reports of intracranial hemorrhage to date. OBSERVATIONS: This is the first documented case of successful MRgFUS thalamotomy in a patient with von Willebrand disease (VWD). A 60-year-old left-handed male had medically refractory ET, VWD type 2B, and a family history of clinically significant hemorrhage after DBS. He underwent right-sided MRgFUS thalamotomy and received a perioperative course of VONVENDI (recombinant von Willebrand factor) to ensure appropriate hemostasis. Postprocedure imaging confirmed a focal lesion in the right thalamus without evidence of hemorrhage. The patient reported 90% improvement of his left-hand tremor and significant improvement in his quality of life without obvious side effects. LESSONS: MRgFUS thalamotomy with peri- and postoperative hematological management is a promising alternative to DBS for patients with underlying coagulopathies.

Direct tumoral puncture embolization of onyx before endoscopic endonasal resection of a massive juvenile angiofibroma for a patient with Von Willebrand disease - A case report and review of literature.

INTRODUCTION: Standard treatment of a juvenile angiofibroma (JNA) is surgical resection, usually with an endoscopic endonasal surgery and a preoperative embolization. However, standard intra-arterial embolization may fail to completely devascularize tumors. A novel technique of direct intranasal intratumoral onyx embolization has been described. The aim of this study is to demonstrate the safety and the usefulness of this embolization technique on a pediatric case of JNA and to compare our results to previously reported cases. PRESENTATION OF CASE: A twelve-year-old patient suffering from Von Willebrand disease presented with a voluminous JNA with intracranial extension. Internal carotid artery (ICA) branches partially vascularized the tumor. The patient had two previous incomplete surgical resections, which were preceded by a standard embolization, due to massive perioperative bleeding. DISCUSSION: A direct intratumoral embolization of onyx safely allowed complete tumoral devascularization. Tumoral resection was then completed by an endonasal endoscopic approach. Surgery time was decreased (4,5 h versus 5,5 and 6,5 h) and blood loss were minimized (300 ml versus 1 l and 1,3 l). No complication occurred. Twelve articles previously reported this embolization technique. We present the first reported case of onyx embolization being used for a pediatric patient with a coagulation disorder and a voluminous tumor. CONCLUSION: A direct intratumoral onyx embolization allowed complete resection of a massive JNA, for a patient with Von Willebrand disease. Our data suggest that this technique is safe and may be instrumental for a JNA's resection, even if little vascularization comes from ICA branches.

Von Willebrand's disease in breast surgery: case report.

Von Willebrand disease is an inherited disorder characterized by deficiency of von Willebrand factor, which contributes to platelet adhesion to the endothelium. Patients with coagulation disorders present a challenge at the time of surgery due to the high risk of presenting heavy bleeding within the procedure or postoperative hematomas. We present a case of a 56-year-old woman with Type 1 von Willebrand's disease who was scheduled for breast explantation with autologous reconstruction, due to the presence of long-standing breast implants. The case was satisfactorily managed by a multidisciplinary team formed by plastic surgery, hematology, and anesthesiology, individualizing the management for the patient's case, obtaining good results and a safe procedure.

Evaluation of an automated von Willebrand factor glycoprotein IbM activity assay compared with 3 alternative von Willebrand factor activity assays.

Background: To overcome deficiencies of the traditional von Willebrand factor (VWF) ristocetin cofactor activity assay (VWF:RCo), several automated assays for VWF platelet-binding activity have been developed. Information on the performance of these assays and their diagnostic utility remains limited. Objectives: To validate the VWF:glycoprotein IbM assay INNOVANCE VWF Ac and compare it with an automated VWF:RCo assay as well as with an automated assay and a manual VWF:Ab assay and to generate reference ranges and analyze reproducibility of the VWF:glycoprotein IbM assay. Methods: Clinical sites enrolled healthy subjects and patients representing the intended use population; VWF activity assays were performed, and results were analyzed. The performance of the INNOVANCE VWF Ac assay was also compared between the BCS XP System and the CS-2500 and CS-5100 analyzers. Results: The INNOVANCE VWF Ac assay correlated well with the VWF:RCo assay and the automated HemosIL VWF:Ab assay, with Pearson coefficients of >.9 and a predicted bias of ≤5.0 IU/dL at VWF levels of 30 IU/dL and ≤5.8 IU/dL at the levels of 50 IU/dL, but correlation and bias were not as good when compared with the REAADS manual VWF:Ab assay. Reference ranges observed for healthy subjects correlated well with previously published findings. Reproducibility of the INNOVANCE VWF Ac assay on the BCS XP System and the CS analyzers was excellent, as was correlation among devices. Conclusion: The characteristics of the INNOVANCE VWF Ac assay regarding comparability with other VWF activity assays, reference ranges, and precision support the use of this assay for evaluation of patients with concern for von Willebrand disease.

Oral surgery in people with inherited bleeding disorder: A retrospective study.

INTRODUCTION: The objectives were to describe the peri-operative management of people with inherited bleeding disorders in oral surgery and to investigate the association between type of surgery and risk of developing bleeding complications. MATERIALS AND METHODS: This retrospective observational study included patients with haemophilia A or B, von Willebrand disease, Glanzmann thrombasthenia or isolated coagulation factor deficiency such as afibrinogenemia who underwent osseous (third molar extraction, ortho-surgical traction, dental implant placement) or nonosseous oral surgery between 2014 and 2021 at Bordeaux University Hospital (France). Patients and oral surgery characteristics were retrieved from medical records. Odds ratio (OR) and 95% confidence interval (CI) were estimated using logistic regression. RESULTS: Of the 83 patients included, general anaesthesia was performed in 16%. Twelve had a bleeding complication (14.5%) including six after osseous surgery. The most serious complication was the appearance of anti-FVIII inhibitor in a patient with moderate haemophilia A. All bleeding complications were managed by a local treatment and factor injections where indicated. No association was observed between type of surgery (osseous vs. nonosseous) and risk of bleeding complications after controlling for sex, age, disease type and severity, multiple extractions, type of anaesthesia and use of fibrin glue (OR: 3.21, 95% CI: .69-14.88). CONCLUSION: In this study, we have observed that bleeding complications after oral surgery in people with inherited bleeding disorders were moderately frequent and easily managed. However, in this study, we observed a serious complication highlighting the necessity of a thorough benefit-risk balance evaluation during the preoperative planning of the surgical and medical protocol.

Primary Total Knee Arthroplasty in Hemophilia and Allied Disorders: Revision Rates and Their Causes.

When patients with hemophilia and allied disorders (von Willebrand disease and other congenital bleeding disorders) do not receive adequate primary hematologic prophylaxis from infancy, their joints will suffer knee joint degeneration; when such joint degeneration becomes very advanced (painful and disabling) despite previous conservative treatment, the only way to alleviate the problem will be to implant a primary total knee arthroplasty (TKA). The literature has shown that twenty years after implantation, 71% of primary TKAs are still functional; on the other hand, 18% have to be revised as a consequence of periprosthetic joint infection (PJI). The main causes of revision total knee arthroplasty are PJI and aseptic loosening (39% each).

Unexpected massive bleeding during the modified LeFort III advancement surgery for Crouzon syndrome: A case report.

Key Clinical Message: Vigilant monitoring for postoperative complications, including bleeding and dysrhythmia, is crucial in patients with craniosynostosis syndromes like Crouzon syndrome undergoing craniofacial surgery, with a thorough evaluation, including coagulation tests, assisting in diagnosing underlying conditions such as von Willebrand disease subtype 1 to inform appropriate management strategies. Abstract: Crouzon syndrome is a rare genetic disorder affecting craniofacial structures. Its etiology is the premature fusion of cranial sutures. The LeFort III advancement surgery is a commonly used approach to correct malformations related to midface hypoplasia. Complications following surgical treatment of craniosynostosis and craniofacial syndromes can include both intracranial and extracranial problems. Reporting of this syndrome and the surgery complications, in addition to consideration of other differential diagnoses, can help improve the treatment plan and surgery outcomes. The aim of the article is to report a 14-year-old female with Crouzon syndrome who underwent the modified LeFort III osteotomy and developed unexpected massive bleeding during the surgery. Post-surgery, she experienced complications including dysrhythmia, hypothermia, and cyanosis. Treatment included fluid therapy, blood transfusions, and antibiotic therapy for suspected septic shock. Differential diagnosis was disseminated intravascular coagulation but was ruled out. Post-discharge, coagulation tests suggested von Willebrand disease subtype 1 as the diagnosis. Excessive bleeding during surgery for craniosynostosis syndromes is a significant and concerning issue in the surgical management of Crouzon syndrome. For patients with von Willebrand disease who are candidates for elective surgeries, von Willebrand factor concentrates or recombinant von Willebrand factor can be used.

Navigating the challenges: a case report on managing a complicated postpartum course in type 3 von Willebrand disease with alloantibodies.

Background: Von Willebrand disease (VWD) type 3 is characterized by a complete deficiency of von Willebrand factor (VWF), resulting in a severe bleeding phenotype. Treatment often requires administration of VWF concentrates/factor (F)VIII. However, the development of alloantibodies is a rare complication, resulting in ineffective recovery and allergic reactions. Emicizumab, a bispecific antibody mimicking FVIII function, has emerged as a potential alternative, with promising results reported in several case reports. Key Clinical Question: Description of multiple approaches to control highly severe postpartum hemorrhage in type 3 VWD with alloantibodies, including off-label use of emicizumab. Clinical Approach: Here we present a 28-year-old patient with type 3 VWD and alloantibodies, known to have arthropathy of the right elbow. Previous immune tolerance induction was unsuccessful. Despite receiving negative pregnancy advice during preconception counseling, the patient became pregnant. Delivery was induced at 38 4/7 weeks with prostaglandin, and recombinant FVIIa (rFVIIa) was administered every 2 hours. Despite administration of rFVIIa, bleeding persisted, requiring manual placental removal and insertion of a Bakri balloon. Since bleeding persisted, plasma-derived VWF was administered with an initial excellent recovery and successful embolization of the uterine artery. Twelve days postpartum, she developed endometritis and recurrent vaginal bleeding treated with antibiotics, rFVIIa every 2 hours, and multiple erythrocyte transfusions. Plasma-derived VWF was administered but was complicated by anaphylaxis and no recovery. Due to persistent vaginal bleeding, reembolization of uterine arteries was performed and off-label emicizumab was initiated. Twenty-nine days postpartum, she developed septic shock requiring an abdominal hysterectomy, again complicated by severe bleeding necessitating direct intraabdominal packing after rFVIIa. A computed tomography scan 9 days postsurgery revealed thrombosis in the left iliac vein and asymptomatic pulmonary embolisms. rFVIIa was stopped and prophylactic low-molecular-weight heparin was started. The patient was discharged 2 months after delivery on low-dose low-molecular-weight heparin, emicizumab, and antibiotics for an intra-abdominal abscess. During 2.5 years of emicizumab prophylaxis, she has had no rebleeding in her arthropathic right elbow. Conclusion: The current case emphasizes the postpartum clinical challenges of patients with type 3 VWD and alloantibodies. It underscores the potential role of emicizumab in maintaining hemostatic control.

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.

Gynecological bleeding in women with congenital bleeding disorders: A comprehensive cohort from Iran.

BACKGROUND: Gynecological bleeding including menorrhagia and postpartum hemorrhage (PPH) face women's quality of life constantly with difficulties, especially those suffering from inherited bleeding disorders. In this study, we aim to evaluate gynecological bleeding particularly menorrhagia among Iranian women patients with inherited bleeding disorders admitted to the Iranian Comprehensive Hemophilia Care Center (ICHCC). METHODS: This study was conducted on 156 females aged ≥ 12 diagnosed with an inherited bleeding disorder in ICHCC. Demographic and laboratory data were documented for all patients. Bleeding questionnaires (the International Society on Thrombosis and Hemostasis bleeding assessment tool (ISTH-BAT), Molecular and Clinical Markers for the Diagnosis and Management of Type 1 von Willebrand disease (MCMDM-1), and Pictorial blood loss assessment chart (PBAC)) were filled out for all patients. For comparing metric and categorical parameters, Mann-Whitney was performed. Spearman's rho test was used for analyzing correlation. RESULTS: The mean age of patients was 33. Von Willebrand disease (VWD), Factor (F) VII deficiency and combined factor deficiency were the most diagnosed disorders. The median of ISTH-BAT, MCMDM-1, and PBAC was 7,7, and 517, respectively. Menorrhagia was the most common reason for diagnosis. Menorrhagia and PPH domain scores ≥ 2 were recorded in 82 and 34 patients, respectively, and PBAC scores > 100 were seen in 118 patients. Significant positive correlations were observed between bleeding scores and menorrhagia and PPH scores. No significant correlations were recorded for VWF: Ag and VWF: RCo with menorrhagia and PPH scores; however, significant correlations were seen for VWF: Ag and VWF: RCo with bleeding score questionnaires. CONCLUSION: Menorrhagia is the most common problem in females affected by different types of inherited bleeding disorders, particularly VWD. Increased awareness among gynecologists and hematologists about bleeding disorders in cases with unexplained menorrhagia is an essential step for optimal management.

Severe haemorrhages leading to a diagnosis of rare bleeding disorder occur at a very young age: A study from the FranceCoag network.

INTRODUCTION: In the context of severe unexplained haemorrhage (SH), it is usual to seek haematological evaluation and investigate for an inherited rare bleeding disorder (IRBD). In such circumstances, appropriate screen can discriminate between IRBD and suspected child abuse. Yet, little information is available about the frequency of SH in the population of patients with IRBD. AIM: To collect epidemiologic data about SH and IRBD. METHOD: The database of the FranceCoag network has collected information about IRBD since January 2004. Based on data gathered up to 16 March 2022, a retrospective search was conducted for of SH events having occurred before or at the time of IRBD diagnosis. Demographics and diagnosis circumstances were retrieved, as well as information about SH, defined as any life-threatening bleeding or intracranial haemorrhage. RESULTS: Among the 13,433 patients of the database, 109 (0.8%) fulfilled inclusion criteria including a known date of IRBD diagnosis, haemophilia A or B (HA/HB) being the most frequent (82.5%). IRBD was discovered as a consequence of an SH event in 82.6% of the cases while CNS was involved in 55%. Severe and moderate HA/HB and other severe IRBD presented significantly more intracranial haemorrhage (p < .02) and a lower age at diagnosis (p = .03). CONCLUSIONS: These data support that any unusual SH should raise a suspicion of IRBD. Particularly before 1-year of age, it is suggested to first confirm moderate or severe haemophilia and severe IRBD by standard coagulation tests (APTT, PT and fibrinogen), combined with a clotting FXIII assay as first-line investigation. Subsequent assays of coagulation factors should be performed in the case of abnormal values, in second-line investigation.

Early diagnosis of persons with von Willebrand disease using a machine learning algorithm and real-world data.

BACKGROUND: Von Willebrand disease (VWD) is underdiagnosed, often delaying treatment. VWD claims coding is limited and includes no severity qualifiers; improved identification methods for VWD are needed. The aim of this study is to identify and characterize undiagnosed symptomatic persons with VWD in the US from medical insurance claims using predictive machine learning (ML) models. RESEARCH DESIGN AND METHODS: Diagnosed and potentially undiagnosed VWD cohorts were defined using Komodo longitudinal US claims data (January 2015-March 2020). ML models were built using key characteristics predictive of VWD diagnosis from the diagnosed cohort. Two ML models predicted VWD diagnosis with the highest accuracy in females (random forest; 84%) and males (gradient boosting machine; 85%). Undiagnosed persons suspected to have VWD were identified using an 80% cutoff probability; profiles of key characteristics were constructed. RESULTS: The trained ML models were applied to the undiagnosed cohort (28,463 females; 20,439 males) with suspected VWD. Fifty-two percent of undiagnosed females had heavy menstrual bleeding, a key pre-diagnosis symptom. Undiagnosed males tended to have more frequent medical procedures, hospitalizations, and emergency room visits compared with undiagnosed females. CONCLUSIONS: ML algorithms successfully identified potentially undiagnosed symptomatic people with VWD, although many may remain undiagnosed and undertreated. External validation of the algorithms is recommended.

Retrospective chart review of GI bleeding in people with von Willebrand disease.

INTRODUCTION: Gastrointestinal (GI) bleeding events (BEs) in von Willebrand disease (VWD) are difficult to diagnose and often recurrent. Limited data from clinical trials has led to lack of consensus on treatment options. AIM: Describe current treatments and outcomes for GI BEs in people with VWD. METHODS: This retrospective, observational, multicentre chart review study was conducted from January 2018 through December 2019 and included patients with inherited VWD with ≥1 GI BE in the preceding 5 years. Baseline characteristics, number and aetiology of BEs, associated GI-specific morbidities/lesions, treatment and outcomes were analysed descriptively. RESULTS: Sixty bleeds were reported in 20 patients with type 1 (20%), type 2 (50%) and type 3 (30%) VWD. During the 5-year study period, 31 (52%) BEs had one identified or suspected cause; multiple causes were reported in 11 (18%). Most GI BEs (72%) were treated with a combination of von Willebrand factor (VWF), antifibrinolytics and/or other haemostatic or non-haemostatic treatments. Time to resolution did not differ by VWF treatment use; however, BEs treated with non-VWF treatments tended to resolve later. In patients with GI-specific morbidities/lesions, 84% resolved with first-line treatment; time to resolution tended to be longer than in patients without such morbidities/lesions. Thirteen BEs occurred in patients receiving prophylaxis and 47 in patients receiving on-demand treatment; 18 BEs resulted in a switch to prophylaxis after bleed resolution. CONCLUSIONS: This study confirms the unmet need for the management of recurrent GI BEs in people with VWD and the need for prospective data, especially on prophylaxis.

Variant mapping using mass spectrometry-based proteotyping as a diagnostic tool in von Willebrand disease.

BACKGROUND: von Willebrand disease (VWD) is the most common inherited bleeding disorder, characterized by either partial or complete von Willebrand factor (VWF) deficiency or by the occurrence of VWF proteoforms of altered functionality. The gene encoding VWF is highly polymorphic, giving rise to a variety of proteoforms with varying plasma concentrations and clinical significance. OBJECTIVES: To address this complexity, we translated genomic variation in VWF to corresponding VWF proteoforms circulating in blood. METHODS: VWF was characterized in VWD patients (n = 64) participating in the Willebrand in the Netherlands study by conventional laboratory testing, DNA sequencing and complementary discovery, and targeted mass spectrometry-based plasma proteomic strategies. RESULTS: Unbiased plasma profiling combined with immune enrichment of VWF verified VWF and its binding partner factor VIII as key determinants of VWD and revealed a remarkable heterogeneity in VWF amino acid sequence coverage among patients. Subsequent VWF proteotyping enabled identification of both polymorphisms (eg, p.Thr789Ala, p.Gln852Arg, and p.Thr1381Ala), as well as pathogenic variants (n = 16) along with their corresponding canonical sequences. Targeted proteomics using stable isotope-labeled peptides confirmed unbiased proteotyping for 5 selected variants and suggested differential proteoform quantities in plasma. The variant-to-wild-type peptide ratio was determined in 6 type 2B patients heterozygous for p.Arg1306Trp, confirming the relatively low proteoform concentration of the pathogenic variant. The elevated VWF propeptide/VWF ratio indicated increased clearance of specific VWF proteoforms. CONCLUSION: This study highlights how VWF proteotyping from plasma could be the first step to bridge the gap between genotyping and functional testing in VWD.