scholarly journals Bleeding Outcomes in People with Von Willebrand Disease Receiving Antithrombotic Therapy

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3196-3196
Author(s):  
Aisling Barrett ◽  
Catherine Bergin ◽  
Mary Byrne ◽  
Kevin Ryan ◽  
Niamh M O'Connell ◽  
...  
Keyword(s):  
Antithrombotic Therapy ◽  
Bleeding Risk ◽  
Von Willebrand Disease ◽  
Cumulative Exposure ◽  
Bleeding Complications ◽  
Gi Bleeding ◽  
Von Willebrand

Abstract Aging brings additional challenges in the management of people with von Willebrand Disease (VWD). Plasma von Willebrand Factor (VWF) levels may increase but the impact on bleeding phenotype is unclear. With the development of age-related comorbidities, the use of antiplatelet (AP) or anticoagulant (AC) therapies may be warranted. As highlighted in the 2021 international VWD guidelines, limited evidence exists regarding the bleeding risk and safety of AP/AC use in people with VWD. 1 We sought to address this knowledge gap through a retrospective review of a large cohort of people with VWD attending a tertiary referral center. The records of all patients aged >50 years (y) attending our center registered with VWD were retrospectively reviewed. We identified all individuals treated with AP and/or AC, recording the indication for and duration of therapy. We also recorded disease subtype, baseline and most recent plasma VWF levels and bleeding on AP and/or AC. Bleeding episodes were stratified according to the World Health Organization (WHO) Bleeding Scale. From 255 eligible patients, 18 patients (7 male, 11 female) were identified who received AP and/or AC over a period of 22y. The median age at commencement was 60.2 years (range 40.0-74.5). 15 patients had Type 1 with baseline levels 30-50 IU/dL, (median VWF antigen, VWF:Ag, 57.5, range 39-87 IU/dL; median VWF ristocetin cofactor levels, VWF:RCo, 43, range 35-54 IU/dL). 3 patients had type 2 VWD (median VWF:Ag 64, range 27-90 IU/dL; median VWF:RCo of 16, range 10-66 IU/dL). The type of AP/AC used and indications for treatment are outlined in Table 1. Overall, 12 patients were treated with AP and 7 with AC therapy (19 therapies in total as one patient received first aspirin then warfarin therapy). The cumulative exposure to AP therapy was 61.9y with a median exposure time of 3.2y/patient (range 0.3-14.1y). Duration of AC therapy was shorter, with a cumulative exposure of 17.6y and a median of 1.5 y/patient (range 0.3-6.3y). Overall, 85.7% of patients on AC therapy had at least one episode of bleeding (6/7; 10 episodes total) in contrast to 58.3% of patients on AP (7/12; 12 episodes total). Of these 22 episodes, 5 (22.7%) were grade 1 bleeding. Grade 2 bleeding (iron deficiency or gastrointestinal (GI), gynecological or genitourinary bleeding) occurred in 5 patients (41.7%) treated with AP and 4 patients (57.1%) on AC (total of 14 episodes). 1 episode of grade 3 bleeding occurred in both the AP (8.3%) and AC (14.3%) group (GI bleeding requiring transfusion and abdominal hematoma respectively). The single grade 4 bleed was an intracranial hemorrhage (ICH) and occurred in a patient with type 2 VWD (VWF:RCo 10 IU/dL) on warfarin for atrial fibrillation; this required prothrombin complex concentrate, VWF concentrate, neurosurgical intervention and cessation of AC. Bleeding complications resulted in discontinuation of therapy in 2 patients (11.1%) treated; the individual with ICH and a patient with type 1 VWD on warfarin (baseline VWF:RCo 43 IU/dL) due to recurrent GI bleeding. No patients treated with AP therapy required discontinuation of use. The overall rate of major bleeding (WHO grade >/=3) in our study was 11.4 events/100 patient-years in VWD patients receiving AC therapy, in comparison to the rate of bleeding in the general population using AC of 7.2 events per 100 patient-years. 2 For patients with type 1 VWD, plasma VWF levels were seen to increase during follow up (median 8.5y, VWF:Ag median +13 IU/dL, VWF:RCo +18 IU/dL), resulting in plasma VWF levels >50 IU/dL for 66.6% of patients in this cohort. Despite this, bleeding while on AP and/or AC was still experienced in 8/10 patients whose levels had normalized, necessitating cessation in one instance. In conclusion, this study provides important insights into the use of AP and/or AC in patients with VWD. Bleeding rates were higher in patients treated with AC therapy than AP resulting in cessation of therapy in 28.6% of those on AC. Bleeding events still occurred despite normalization of plasma VWF levels in patients with type 1 VWD. These data highlight the need for close follow up of patients with VWD whilst on antithrombotic therapy, particularly AC. 1. Connell NT et al. ASH ISTH NHF WFH 2021 guidelines on the management of von Willebrand disease. Blood Adv 2021;5(1):301-325. 2. Shoeb M, Fang M. Assessing Bleeding Risk in Patients Taking Anticoagulants. J Thromb Thrombolysis 2013;35(3):312-319. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Toward Personalized Treatment for Patients with Low von Willebrand Factor and Quantitative von Willebrand Disease

2021 ◽  
Vol 47 (02) ◽  
pp. 192-200
Author(s):  
James S. O'Donnell
Keyword(s):  
Von Willebrand Factor ◽  
Bleeding Risk ◽  
Von Willebrand Disease ◽  
Personalized Treatment ◽  
Treatment Plans ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

AbstractThe biological mechanisms involved in the pathogenesis of type 2 and type 3 von Willebrand disease (VWD) have been studied extensively. In contrast, although accounting for the majority of VWD cases, the pathobiology underlying partial quantitative VWD has remained somewhat elusive. However, important insights have been attained following several recent cohort studies that have investigated mechanisms in patients with type 1 VWD and low von Willebrand factor (VWF), respectively. These studies have demonstrated that reduced plasma VWF levels may result from either (1) decreased VWF biosynthesis and/or secretion in endothelial cells and (2) pathological increased VWF clearance. In addition, it has become clear that some patients with only mild to moderate reductions in plasma VWF levels in the 30 to 50 IU/dL range may have significant bleeding phenotypes. Importantly in these low VWF patients, bleeding risk fails to correlate with plasma VWF levels and inheritance is typically independent of the VWF gene. Although plasma VWF levels may increase to > 50 IU/dL with progressive aging or pregnancy in these subjects, emerging data suggest that this apparent normalization in VWF levels does not necessarily equate to a complete correction in bleeding phenotype in patients with partial quantitative VWD. In this review, these recent advances in our understanding of quantitative VWD pathogenesis are discussed. Furthermore, the translational implications of these emerging findings are considered, particularly with respect to designing personalized treatment plans for VWD patients undergoing elective procedures.

scholarly journals Bleeding Symptoms and von Willebrand Factor Levels: 30-Year Experience in a Tertiary Care Center

2019 ◽  
Vol 25 ◽  
pp. 107602961986691
Author(s):  
Chatphatai Moonla ◽  
Benjaporn Akkawat ◽  
Yaowaree Kittikalayawong ◽  
Autcharaporn Sukperm ◽  
Mukmanee Meesanun ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Care Center ◽  
Tertiary Care ◽  
Bleeding Risk ◽  
Binding Activity ◽  
Von Willebrand Disease ◽  
Von Willebrand ◽  
Willebrand Factor

Correlations between bleeding symptoms and von Willebrand factor (VWF) levels may help to predict hemorrhagic severity in the Westerners with von Willebrand disease (VWD), but data in Asians are lacking. In this study, Thai patients with VWF levels <50 IU/dL without any secondary causes were enrolled from 1988 to 2018 to determine the relationship between VWF levels and hemorrhagic manifestations. According to the current concept, we reclassified VWD and low VWF by VWF levels ≤30 and 30 to 50 IU/dL, respectively. Type 2 VWD was diagnosed if VWF activity to antigen ratio was ≤0.6. Bleeding severity was determined by the condensed MCMDM-1VWD bleeding score (BS). Among 83 patients, VWF activities showed negative correlations with BS ( P = .001), which were higher in type 2 (median: 7, interquartile range [IQR]: 5-11) compared with type 1 VWD (median: 3, IQR: 2-4) and low VWF (median: 4, IQR: 2-8). Bleeding symptoms were indistinguishable between type 1 VWD and low VWF using the 30 IU/dL cutoff point. However, VWF ristocetin cofactor activity or gain-of-function mutant glycoprotein Ib binding activity <36.5 IU/dL and VWF collagen binding activity <34.5 IU/dL could predict increased bleeding risk (BS ≥3) by 92.3% specificity and 70.0% sensitivity ( P < .0001).

Recessive von Willebrand Disease Type 2 Normandy: Variable Expression of Mild Hemophilia and VWD Type 1

2009 ◽  
Vol 121 (2-3) ◽  
pp. 119-127 ◽  
Author(s):  
Jan Jacques Michiels ◽  
Alain Gadisseur ◽  
Inge Vangenegten ◽  
Wilfried Schroyens ◽  
Zwi Berneman
Keyword(s):  
Disease Type ◽  
Von Willebrand Disease ◽  
Variable Expression ◽  
Von Willebrand

Identification of Type 2 von Willebrand Disease in Previously Diagnosed Type 1 Patients: a Reappraisal Using Phenotypes, Genotypes and Molecular Modelling

2000 ◽  
Vol 84 (12) ◽  
pp. 998-1004 ◽  
Author(s):  
Ioana Nitu-Whalley ◽  
Anne Riddell ◽  
K. Pasi ◽  
Dale Owens ◽  
M. Enayat ◽  
...  
Keyword(s):  
Molecular Modelling ◽  
Correct Diagnosis ◽  
Von Willebrand Disease ◽  
Single Amino Acid ◽  
Elisa Assay ◽  
Modelling Analysis ◽  
A1 Domain ◽  
Von Willebrand

SummaryIn order to investigate the possibility that qualitative type 2 defects in von Willebrand factor (VWF) occurred in patients previously diagnosed with quantitative type 1 von Willebrand disease (VWD), the phenotypes and genotypes were reanalysed in 30 patients who exhibited discrepant VWF activity/VWF:Ag ratios of less than 0.7. The capacity of VWF to bind to glycoprotein Ib (GpIb) was reassessed using the ristocetin co-factor activity (VWF:RiCo) assay compared to an in-house and a commercial ELISA assay (based on a mAb directed against the GpIb binding site on VWF). This was supplemented by multimeric analysis and the amplification and sequencing of a 936 bp fragment of exon 28 of the VWF gene with the aim of identifying mutations in the A1 domain. On reappraisal, using the VWF:RiCo assay all patients demonstrated a disproportionately reduced VWF:RiCo/VWF:Ag ratio, indicative of a qualitative defect, while abnormal ratios were detected in only seven kindreds using the in-house ELISA assay and in only one kindred with the commercial ELISA assay. Eight single amino acid substitutions were found in nine kindreds, four of which were novel candidate VWF mutations and four previously described in association with type 2 VWD. In agreement with the phenotype, the novel VWF mutations were located in the VWF-A1 crystal structure at positions that corresponded to potential type 2M defects. This study underlines the difficulties of correct diagnosis of the subtype of VWD and emphasises the importance of using sensitive phenotypic assays, the relevance of the VWF:RiCo/ VWF:Ag ratio, multimeric analysis and molecular modelling analysis.

Major haemorrhage related to surgery in patients with type 1 and possible type 1 von Willebrand disease

2008 ◽  
Vol 100 (05) ◽  
pp. 797-802 ◽  
Author(s):  
Alicia Blanco ◽  
Roberto Chuit ◽  
Susana Meschengieser ◽  
Ana Kempfer ◽  
Cristina Farías ◽  
...  
Keyword(s):  
Family History ◽  
Surgical Procedures ◽  
Tooth Extraction ◽  
Positive Family History ◽  
Major Haemorrhage ◽  
Von Willebrand Disease ◽  
Bleeding Complications ◽  
Laboratory Test Results ◽  
Von Willebrand

SummaryPatients with von Willebrand disease (VWD) frequently bleed under a challenge. The aim of our study was to identify predictive markers of perioperative major haemorrhage in type 1 (VWF:RCo = 15–30 IU dl-1) and possible type 1 (VWF:RCo = 31–49 IU dl-1)VWD patients. We recorded perioperative bleeding complications previous to diagnosis and laboratory parameters in 311 patients with 498 surgical procedures. The patients were grouped according to the absence (A) or presence (B) of perioperative major haemorrhages. Eighty-one patients (26%) and 87 surgical procedures (17.5%) presented major haemorrhages associated with surgeries. There was no difference between the percentage of type 1 and possible type 1 VWD patients who had major haemorrhages (32.6% and 24.8% respectively; p=ns). No difference in the prevalence of O blood group, age, gender, positive family history and laboratory test results (FVIII and VWF) was observed, independent of the haemorrhagic tendency. Bleeding after tooth extraction was the most frequent clinical feature observed in patients with perioperative major haemorrhages. The bleeding score and the number of bleeding sites (≥3) were not predictors of major haemorrhage associated with surgery. Caesarean section and adenotonsillectomy showed the highest frequency of major haemorrhages (24.6% and 22.3%, respectively). In conclusion, type 1 and possible type 1VWD patients showed similar incidence of perioperative major haemorrhages. Laboratory tests and positive family history did not prove to be effective at predicting major haemorrhages in patients that had either type 1 or possible type 1 VWD. The history of bleeding after tooth extraction could define risk factors of major haemorrhage.

Incidence of Bleeding Complications in Pediatric Patients with Type 1 von Willebrand Disease Undergoing Adenotonsillar Procedures

2009 ◽  
Vol 155 (1) ◽  
pp. 68-72 ◽  
Author(s):  
Char M. Witmer ◽  
Lisa Elden ◽  
Regina B. Butler ◽  
Catherine S. Manno ◽  
Leslie J. Raffini
Keyword(s):  
Pediatric Patients ◽  
Von Willebrand Disease ◽  
Bleeding Complications ◽  
Von Willebrand

Limitations of Current Plasma VonWillebrand Factor (VWF) Activity Tests: A Comprehensive Comparison of Five VWF Activity Assays.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3376-3376
Author(s):  
Dong Chen ◽  
Rajiv Pruthi ◽  
William L. Nichols ◽  
John A. Heit
Keyword(s):  
Activity Ratio ◽  
Light Transmission ◽  
Von Willebrand Disease ◽  
Assay Method ◽  
Type I ◽  
Platelet Activity ◽  
Platelet Aggregometry ◽  
Von Willebrand

Abstract Accurate measurement of plasma von Willebrand factor (VWF) activity is essential for the laboratory diagnosis and treatment monitoring of von Willebrand disease (VWD). Currently available VWF activity assays include VWF ristocetin cofactor activity by manual light transmission platelet aggregometry (VWF:RCo–Agg) or flow cytometry (VWF:RCo–FL), collagen I and III binding activity (VWF:Co–I and –III) (Technozym), and platelet activity by latex agglutination (VWF:Lx) (Instrumental Laboratory). In this study we evaluated and compared the accuracy and precision of these 5 assay methods. Plasma samples from 11 normal donors and 41 patients categorized as type 1 (n=20) or type 2 (n=21) VWD based on clinical evaluation, fVIII:C activity, VWF:RCo–Agg, VWF antigen (VWF:Ag) level and plasma VWF multimer analysis by agarose gel electrophoresis were assayed for VWF activity by VWF:RCo–FL, VWF:Co–I, VWF:Co–III and VWF:Lx methods. The VWF:Ag/VWF activity ratio by VWF activity assay method was calculated for each sample. For normal donors and type I VWD patients, VWF:RCo–FL and VWF:Lx correlated well with VWF:RCo–Agg (R2=0.87, and 0.97, respectively), while VWF:Co–I and –III were lower compared to VWF:RCo-Agg. For type 2 VWD patients, different VWF:Ag/VWF activity ratio cutoffs (range 0.3–0.7) were used (Figure). Both VWF:RCo–Agg and –FL were sensitive (95%) and specific (97%) for type 2 VWD while the VWF:Lx was slightly less sensitive (81%) but was very specific (100%). VWF:Co–I and –III were the least sensitive (<90%) and specific (<90%); both methods had high false positive and negative rates for type 2 VWD. In Summary, for normals and type 1 VWD patients, VWF:RCo–FL and VWF:Lx correlate well with VWF:RCo–Agg and have similar sensitivities and specificities for type 2 VWD. VWF:Co–I and –III are unreliable for assessing plasma VWF activity.

A Two-Year Prospective Study on Bleeding Tendency In 105 Patients with Type 2 A and M Von Willebrand Disease

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 543-543
Author(s):  
Giancarlo Castaman ◽  
Augusto B. Federici ◽  
Luciano Baronciani ◽  
Pier M. Mannucci ◽  
Francesco Rodeghiero
Keyword(s):  
Molecular Weight ◽  
Gastrointestinal Bleeding ◽  
High Molecular Weight ◽  
Von Willebrand Disease ◽  
Bleeding Tendency ◽  
Bleeding Episodes ◽  
Von Willebrand ◽  
High Molecular Weight Multimers

Abstract Abstract 543 Background: Type 2 A and 2 M von Willebrand Disease (VWD) are both characterized by the presence of a dysfunctional von Willebrand factor (VWF) and a variable bleeding tendency. The bleeding incidence and possible clinical differences between these two types have never been investigated prospectively in a large number of patients. Aims and design of the study: To investigate clinical history and determinants of bleeding in a cohort of patients (pts) with type 2 A and M VWD characterized by mutations over 24 months of follow-up. Patients and Methods: 10 families with type 2 A VWD (47 patients) and 15 with type 2 M (58 patients) with type 2 M VWD were diagnosed according to the recommendations of the ISTH-SSC subcommittee on VWF and prospectively followed-up from April 2007 to March 2009. Bleeding score (BS) was calculated in all the patients at enrollment by the administration of the same questionnaire tested in type 1 VWD. In case of VWF:RCo levels < 10 U/dL, all patients were tested with a more sensitive ELISA assay to calculate ratios between VWF:RCo and VWF:Ag. VWF mutations were identified in all the patients. Results: The 105 patients were characterized by the following mutations: type 2 A R202W/R1583Q 1 pt, S1506L 11 pts, S1543F 1 pt, R1596W 3 pts, V1607D 8 pts, I1628T 1 pt, G1629R 1 pt, G1631D 9 pts, V1665E 8 pts, Q2520P 2 pts, multiple changes 1 pt. Type 2 M: L1278P 6 pts, R1315L 3 pts, R1315C 9 pts, Y1321C 9 pts, L1361W 4 pts, R1374H 23 pts, C1927/c.8155+6C>T 1 pt, c.3831del-3 3 pts. The table summarizes the main demographic and laboratory characteristics. All the patients had a VWF:RCo/VWF:Ag ratio <0.6. The mean BS and VWF:Ag were significantly higher in type 2 A (P < 0.01). No correlation between VWF:RCo levels and the severity of BS was observed. During follow-up, the bleeding episodes in patients with type 2 M and R1374H or R1315C mutations were very few and mild while they were recurrent and severe in those with type 2 A and V1665E or G1631D mutations, the only laboratory difference being the lack of high molecular weight multimers in type 2 A VWD. Furthermore, 44 gastrointestinal bleeding episodes occurred in 15 patients with type 2 A (range 1–7) compared to 8 episodes in 2 patients with type 2 M (range 2–6). Older age was strongly related to the risk of recurrence of this type of bleeding. Conclusions: Bleeding tendency in type 2 A VWD is higher than that of type 2 M VWD and it is not related to the reduction of FVIII:C and VWF activity. The risk of gastrointestinal bleeding is greater in type 2 A and might be related to the lack of high molecular weight multimers and older age. Further analysis are required to evaluate the definite impact of some mutations on the different bleeding tendency. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Wish-Qol Study - Assessment of Health-Related Quality of Life (HRQoL) and Health-Economic Aspects in Patients with Von Willebrand Disease (VWD) in France: Results of the Women Cohort

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1395-1395
Author(s):  
Annie Borel-Derlon ◽  
Jenny Goudemand ◽  
Dominique Desprez ◽  
Fabienne Volot ◽  
Yves Gruel ◽  
...  
Keyword(s):  
Interim Analysis ◽  
Research Funding ◽  
Von Willebrand Disease ◽  
Female Group ◽  
Bleeding Score ◽  
Type 3 ◽  
Von Willebrand

Abstract Background: Von Willebrand disease (VWD) is the most common inherited bleeding disorder with a prevalence of 1% in the general population. VWD results from a deficiency in or a dysfunction of von Willebrand factor which is a protein that is necessary for normal platelet adhesion and protection of factor VIII from proteolysis in the circulation. Nevertheless, prevalence of the most symptomatic forms such as bleeds requiring replacement treatment and /or hospitalization is about 0.01%. Although VWD affects both genders, there is a higher proportion in females than in males.VWD seems to be more symptomatic in women because of their reproductive life. Women with VWD have an increased bleeding risk in numerous situations including anemia, menorrhagia, bleeding during pregnancy, postpartum hemorrhage and impairments in their quality of life (QoL).The prevalence of menorrhagia in women with VWD is 74-92%. According to the Francecoag Network, the referral-based prevalence of moderate-to-severe VWD patients is about 1,750 cases in France. Aim: Since the disease and its treatment can affect every-day life of patients and their families, a French HRQoL Study (WiSH-QoL) exploring this impact started 22 months ago. Methods: This non-interventional 5-year study evaluates patients HRQoL and costs of care in France. At least 350 patients will be followed for 24 months in minimum 30 centers. HRQoL is assessed with the generic SF-36 and the disease-specific VWD-QoL questionnaires. Bleeding severity was measured using the Tosetto Bleeding Score (BS). Results: Since October 2014, 245 patients have been included. We present here the first interim analysis with a focus on the female group. At the first interim analysis, data from 140 patients were documented: 91 adults with a median age of 40.0 years [18.3-78.0] and 49 children with a median age of 10.1 years [2.9-17.5]. VWD Types were already identified for 122 (87%) of these patients: 33 with VWD type 1 (27%) including 5 type 1 Vicenza; 76 type 2 (62%) and 13 type 3 (11%). The median Tosetto bleeding score reported for 124 patients (males and females) was +7 ranging from -1 to +28. From the 95 female patients, 70 were aged ≥18 years, 21 were adolescents between 8-17 years and 4 were girls below 4 years of age. Median age was 29.4 (range 4.3-78.0) years. A total of 25 women had type 1 VWD (31%), 49 had type 2 VWD (60%), and 7 had type 3 VWD (9%), for 14 patients VWD type is undetermined. The median Tosetto bleeding score of the female group was +8 ranging from -1 to +28. Out of 95 patients, 45 patients (47.4%) have received a concomitant treatment due to menorrhagia, such as iron therapy, oral contraceptive, levonorgestrel intrauterin system: 5/21 patients in the group between 8 and 17 years and 40/70 in the group ≥18 years. Out of the 60 women of childbearing potential defined as age between 15-50 years, 6 women were pregnant at time of inclusion. A total of 46 patients, aged 18 years or more have had obstetrical history prior to study inclusion. The mean number of childbirth was more than 2 i.e 2.39 range (1-8) per woman, 75% of these deliveries were natural delivery and 25% were caesarean section. Out of 108 deliveries, 28 (26%) were experienced with post-partum hemorrhages. Conclusions: With the results of the WiSH-QoL study, the first prospective study of von Willebrand disease conducted in France, especially the VWD-specific evaluation of HRQoL and treatment satisfaction a deeper insight will be gathered into the patients' daily life, their perception of well-being and their specific health care needs. With the additional domain 'pregnancy' included in the French version of the VWD-QoL questionnaire for female adult patients, it will possible to better understand how women may be affected by VWD during childbearing years. Disclosures Borel-Derlon: LFB: Other: Reference expert and national coordinator for VWD; Octapharma: Research Funding; NovoNordisk: Other: Expert for scientific committee; Shire - Baxalta: Research Funding. Chatelanaz:LFB Biomedicaments: Employment. Doriat-Robin:LFB Biomedicaments: Employment. von Mackensen:SOBI: Research Funding; Shire: Research Funding.

scholarly journals Semiautomatic VWF Multimer Densitometric Analysis: Validation of the Clinical Accuracy and Clinical Implications in Von Willebrand Disease

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 15-16
Author(s):  
Ferdows Atiq ◽  
Johan Boender ◽  
Marjon H. Cnossen ◽  
Johanna G van der Bom ◽  
Karin Fijnvandraat ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Research Funding ◽  
Von Willebrand Disease ◽  
Densitometric Analysis ◽  
Travel Grant ◽  
Bleeding Score ◽  
Type 3 ◽  
Von Willebrand

Introduction Von Willebrand factor (VWF) multimer analysis is an essential tool in the diagnosis and classification of von Willebrand disease (VWD). Current visual VWF multimer analysis is observer dependent, time consuming and is inaccurate in detecting subtle changes in multimer patterns. Therefore, recent studies have investigated VWF multimer quantification using semiautomatic densitometric analysis. The accuracy of VWF multimer densitometric analysis in clinical practice needs further investigation before it can be widely used. The aim of the study was to validate the accuracy of VWF multimer densitometric analysis in clinical practice. Additionally, we aimed to identify patient characteristics associated with VWF multimer densitometry outcomes in type 1 and type 2 VWD patients, and we investigated whether subtle differences in VWF multimer pattern are associated with the bleeding phenotype of VWD patients. Methods We included patients from the nationwide Willebrand in the Netherlands (WiN) study. The inclusion criteria of the WiN study were a personal hemorrhagic diathesis or family history of VWD, and historically lowest VWF antigen (VWF:Ag), VWF activity (measured with the monoclonal antibody assay: VWF:Ab) or VWF collagen binding (VWF:CB) ≤0.30 IU/mL or FVIII activity (FVIII:C) ≤0.40 IU/mL in case of type 2N VWD. At inclusion in the WiN study, blood was drawn and patients filled in an extensive questionnaire containing a self-administered Tosetto bleeding score (BS). For multimer analysis, citrated blood samples were separated on 0.9% agarose gel and visualized by Western blotting. We used IMAGEJ for densitometric analysis. The five smallest bands on densitometric images were defined as small multimers, next five bands were defined as medium multimers and the remaining bands were defined as large multimers. Medium-large VWF multimer index was calculated by dividing the patient's multimer ratio (intensity of the medium and large multimers divided by the total intensity of all multimers) by the multimer ratio of a normal control in the same western blot. If no multimers could be detected, the multimer index was set as 0. Results We included 561 VWD patients: 328 type 1, 211 type 2 and 21 type 3 patients. The median age was 44 [IQR 29-58] and 351 patients (62.7%) were female (Table 1). Figure 1 illustrates typical densitometric outcomes of a type 1 VWD patient with normal VWF multimers (A) and a type 2A patient with reduced high-molecular-weight (HMW) VWF multimers (B). Medium-large VWF multimer index was 1.06 [0.99-1.12] in type 1 and 0.53 [0.29-0.89] in type 2 and 0.00 [0.00-0.00] in type 3 VWD. Medium-large VWF multimer index was in patients visually classified as normal, reduced and absent HMW VWF multimers, respectively 1.07 [1.02-1.12], 0.84 [0.71-0.91] and 0.31 [0.20-0.44] (p&lt;0.001, Figure 2A). With visual examination as gold standard, medium-large VWF multimer index had a very good accuracy in distinguishing normal VWF multimers from reduced HMW VWF multimers (AUC: 0.96 (0.94-0.98) p&lt;0.001, Figure 2B). It could also accurately distinguish reduced HMW VWF multimers from absence of HMW multimers, with an AUC of 0.95 (0.92-0.97, p&lt;0.001), and type 2A and 2B from type 2M and 2N (AUC: 0.96 (0.94-0.99), p&lt;0.001, Figure 2C and 2D). From VWF activity measurements, medium-large VWF multimer index was strongest correlated with VWF:CB (ρ=0.79, p&lt;0.001). From the ratio of the various functional VWF measurements (divided by VWF:Ag), the strongest correlation was again found for VWF:CB/VWF:Ag ratio (ρ=0.80, p&lt;0.001). In type 1 VWD, an increased clearance of VWF (defined as VWFpropeptide/VWF:Ag ratio ≥2.2) was independently associated with lower medium-large VWF multimer index (β=-0.10 (-0.14; -0.07), p&lt;0.001). Also, type 1 VWD patients with a VWF gene variant had relatively lower medium-large VWF multimer index compared to type 1 patients without a VWF variant, respectively 1.03 [0.95-1.10] vs 1.08 [1.04-1.12] (p&lt;0.001). In the total population, higher medium-large VWF multimer index was associated with a lower bleeding score: β=-4.6 (-7.2; -2.0), p=0.001, adjusted for age, sex, blood group and type of VWD. Conclusion Semiautomatic densitometric analysis of VWF multimers has an excellent accuracy in clinical practice, and may have an additional value in providing a better understanding of the clinical features such as the bleeding phenotype of VWD patients. Disclosures Atiq: CSL Behring: Research Funding; SOBI: Other: travel grant. Boender:SOBI: Current Employment; CSL Behring: Research Funding. Cnossen:Bayer: Research Funding; Novo Nordisk: Research Funding; Nordic Pharma: Research Funding; Sobi: Research Funding; Takeda: Research Funding; CSL behring: Research Funding; Pfizer: Research Funding; Shire: Research Funding; Baxter: Research Funding. van der Bom:Bayer: Speakers Bureau. Fijnvandraat:SOBI: Research Funding; NovoNordisk: Consultancy; Grifols: Consultancy; Takeda: Consultancy; Roche: Consultancy; CSL Behring: Research Funding; NovoNordisk: Research Funding. Van Galen:Bayer: Research Funding; Takeda: Speakers Bureau; CSL Behring: Research Funding. Laros-Van Gorkom:Baxter: Other: Educational grant; CSL Behring: Other: Educational grant. Meijer:Bayer: Research Funding; Sanquin: Research Funding; Pfizer: Research Funding; Bayer: Speakers Bureau; Sanquin: Speakers Bureau; Boehringer Ingelheim: Speakers Bureau; BMS: Speakers Bureau; Aspen: Speakers Bureau; Uniqure: Consultancy. Eikenboom:CSL Behring: Research Funding; Roche: Other: Teacher on educational activities. Leebeek:Roche: Other: DSMB member for a study; SOBI: Other: Travel grant; Novo Nordisk: Consultancy; Shire/Takeda: Consultancy; Uniqure: Consultancy; Shire/Takeda: Research Funding; CSL Behring: Research Funding.

Sign in / Sign up

Export Citation Format

Share Document