Genetic Modifiers of Thrombosis in Mice.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. SCI-44-SCI-44
Author(s):  
David Ginsburg
Keyword(s):  
Large Scale ◽  
Genetic Factors ◽  
Conflicts Of Interest ◽  
Factor V Leiden ◽  
Mouse Genetics ◽  
Von Willebrand Disease ◽  
Modifier Genes ◽  
Factor V ◽  
Genetic Modifiers ◽  
Von Willebrand

Abstract Abstract SCI-44 The genetic factors responsible for the highly variable clinical course of inherited bleeding disorders including von Willebrand disease and hemophilia are largely unknown. Similar factors are also likely to contribute to the variability of common thrombotic disorders, including factor V Leiden. Studies by our lab over the past 10 years have used the power of mouse genetics to identify genes contributing to this variability (referred to as ‘modifier‘ genes). By performing genetic crosses between inbred strains of mice with elevated plasma levels of von Willebrand Factor (VWF) and other strains with low levels, we have mapped a total of 6 genetic factors contributing to the control of murine plasma VWF levels. Similar studies in ADAMTS13-deficient mice are in progress aimed at characterizing genes modifying susceptibility thrombotic thrombocytopenic purpura. We have also conducted large scale mutagenesis studies in the mouse in an effort to identify larger numbers of genes contributing to thrombosis risk in the setting of Factor V Leiden, and most recently are extending this approach to similar genetic screens in zebrafish. Finally, recent advances in human genetics are expanding the potential opportunities for directly identifying bleeding and thrombosis modifier genes in humans. Disclosures No relevant conflicts of interest to declare.

Protein-Z-Mangel bei ungeklärter Neigung zu Thrombosen, Blutungen oder Aborten

2012 ◽  
Vol 32 (S 01) ◽  
pp. S95-S97
Author(s):  
H. Radtke ◽  
A. Jainz ◽  
F.-P. Schmidt ◽  
H. Kiesewetter
Keyword(s):  
Factor V Leiden ◽  
Disease Type ◽  
Von Willebrand Disease ◽  
Bleeding Complications ◽  
Factor V ◽  
Protein Z ◽  
Factor V Leiden Mutation ◽  
Vein Occlusion ◽  
Retinal Branch Vein Occlusion ◽  
Von Willebrand

SummaryA protein Z deficiency is presumably related with a threefold risk of venous and arterial thrombosis. Mucosal bleedings and post-operative haematomas can occur more frequently. This is seen in an increased in vivo bleeding time without other plasmatic coagulation disorders or thrombopathies. Pregnancy complications, especially abortions before the 15th week of gestation, are described as well. Patients, methods: Since May 2011 the plasmatic concentration of protein Z has been tested in 684 patients of the Hämostaseologicum. Results: In 74 patients a protein Z deficiency has been found. In other 45 patients protein Z was reduced because of the intake of phenprocoumon or coumadin. Of the 74 patients with diminished protein Z concentration 39 were marginally decreased (protein Z 1000–1500 μg/l). Of the 35 patients with a protein Z concentration <1000 μg/l 12 had had a thrombosis before (6 strokes, 3 DVT or PE, 1 arterial thrombosis, 1 retinal branch vein occlusion, 1 acute hearing loss). 7 had arterial hypertension, 2 suffered from diabetes mellitus. Of the patients who had a thrombosis 6 had a heterozygous factor V Leiden mutation. 10 had a microcirculation disorder (Raynaud’s phenomenon), 4 had had bleeding complications before, 3 had a von Willebrand disease type I, 6 patients had had abortions and 4 were healthy. Of the 39 patients with protein Z concentrations between 1000 and 1500 μg/l 18 had experienced a thrombosis before (9 DVT or PE, 3 myocardial infarctions, 1 CHD, 3 strokes, 1 retinal branch vein occlusion, 1 PAOD I, 1 tinnitus). 5 additionally had arterial hypertension. 13 suffered from Raynaud’s phenomenon, of which 7 had a hypotension. Of the patients with thromboses 3 had a heterozygous factor V Leiden mutation and one a protein C deficiency. 7 patients had had an abortion before. Bleeding complications were seen in 4 patients, of which 3 suffered from von Willebrand disease type 1.

Role of Inherited Bleeding Disorders in Women with Pregnancy Loss

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4657-4657
Author(s):  
Manuela Krause ◽  
Daniele Pillitteri ◽  
Ann-Kathrin Pilgrimm ◽  
Thomas Scholz ◽  
Rainer Schwerdtfeger ◽  
...  
Keyword(s):  
Pregnancy Loss ◽  
Conflicts Of Interest ◽  
Fetal Loss ◽  
Factor V Leiden ◽  
Mthfr C677t ◽  
Von Willebrand Disease ◽  
Factor V ◽  
Bleeding Disorders ◽  
Increased Risk ◽  
Fv Leiden

Abstract Abstract 4657 Introduction: Pregnancy is a hypercoagulable state, and thromboembolism is the leading cause of antepartum and postpartum maternal mortality. Women with thrombophilic mutations (factor V leiden, prothrombin, and MTHFR) and inherited bleeding disorders, such as deficiency of factor XIII and fibrinogen, have been shown to be at increased risk of pregnancy loss. However, the risk of miscarriage in women with other inherited bleeding disorders has been discussed controversially. Due to the lack of data, it cannot be determined if the risk of miscarriage is increased in women with von Willebrand disease (vWD). The aim of our study was to clarify the association between inherited bleeding disorders and pregnancy loss. Patients and Methods: Subjects Concerning this investigation we included 91 female patients with two [n=46] or more [n=45] miscarriages occurring prior to 28 weeks of gestation and/or stillbirth without apparent reason. The median age of the examined group at the time of first fetal loss was 29 years, ranging from 17 to 41 years. Methods At first we compiled a detailed clinical history of bleedings of all patients. Subsequently, we performed various tests to gather information regarding coagulation abnormalities and thrombophilic defects. Therefore a molecular and functional assessment of the following data was performed: Coagulation factors, vWF:Ag, vWF:RCo, phospholipid antibodies, hyperhomocysteinaemia (HHCY), protein S (PS), protein C (PC), antithrombin (AT) and FV-Leiden mutation (G1691A), FII mutation (G20210A) and MTHFR C677T. Results: In our investigated population consisting of 91 women we registered 299 pregnancies of which 240 resulted in fetal loss, 232 prior to week 28 of pregnancy and 8 stillbirths. Seven out of 91 patients (8%) were carriers of inherited coagulation disorders; vWD: n=2 (2%), FVII deficiency: n=3 (3%), thrombocytopathy: n=2 (2%). In our study collective there was no increased rate of patients with vWD. None of the patients showed a FXIII- or fibrinogen deficiency. However, 17 patients (19%) have a bleeding diathesis. In 55 patients (60%) we could detect the following thrombophilic defects: FV-Leiden (G1691A): n=10, MTHFR C677T: n=42, PS: n=1, PC: n=1, APS: n=1. Conclusion: The incidence of vWD patients in our miscarriage collective is the same as the overall incidence of vWD patients in the general population. Therefore vWD is not associated with an increased risk of fetal loss. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Case-based discussion on the implications of exogenous estrogens in hemostasis and thrombosis: the obstetrician’s view

Hematology ◽  
2019 ◽  
Vol 2019 (1) ◽  
pp. 148-151
Author(s):  
Andra H. James
Keyword(s):  
Factor V Leiden ◽  
Von Willebrand Disease ◽  
Heavy Menstrual Bleeding ◽  
Menstrual Bleeding ◽  
Ovarian Cysts ◽  
Multiple Gestation ◽  
Factor V ◽  
Clinical Scenarios ◽  
Von Willebrand

Abstract This is the obstetrician’s view on 3 different clinical scenarios involving bleeding and thrombotic disorders. In the first scenario, an 18 year old with a history of heavy menstrual bleeding since menarche presents with abdominal pain and ultrasound findings suggestive of a hemorrhagic ovarian cyst. The association with an underlying bleeding disorder is recognized. The goals of management, which are controlling hemorrhage and preserving fertility, are stated. Ovarian suppression, the most effective method to prevent recurrent hemorrhagic ovarian cysts, is outlined. Long-term management of heavy menstrual bleeding with hormonal contraception is described. In the second scenario, the same patient returns 5 years later for a preconception visit. The potential risks to an unborn baby with von Willebrand disease (VWD) are addressed. The natural rise in von Willebrand factor (VWF) during pregnancy is discussed, but the fact that women with VWD do not achieve the same VWF levels as women without VWD is emphasized and the implications are presented. In anticipation of pregnancy, the need for nonhormonal management of heavy menstrual bleeding and hemorrhagic ovarian cysts is mentioned. In the third and final scenario, the patient’s cousin with factor V Leiden seeks consultation regarding the risks of thrombosis with in vitro fertilization. The steps of assisted reproductive technology are described. The strategies to prevent venous thromboembolism by preventing ovarian hyperstimulation and reducing the likelihood of multiple gestation are detailed.

Effect of hemostatic risk factors on the individual probability of thrombosis during pregnancy and the puerperium

2003 ◽  
Vol 90 (07) ◽  
pp. 77-85 ◽  
Author(s):  
Andrea Gerhardt ◽  
Rainer Zotz ◽  
Rüdiger Scharf
Keyword(s):  
Venous Thromboembolism ◽  
Odds Ratio ◽  
Factor V Leiden ◽  
Factor V ◽  
G20210a Mutation ◽  
Individual Probability ◽  
History Of ◽  
Normal Women ◽  
The Individual ◽  
Von Willebrand

SummaryIn a retrospective study of 190 women with a first history of venous thromboembolism during pregnancy and the puerperium and 190 age-matched women with at least one prior pregnancy and no history of venous thromboembolism, the individual probability of thrombosis was determined. Assuming an overall risk of 1 in 1500 pregnancies, the probability of pregnancy-related thrombosis in carriers of homozygous factor V Leiden was 1 in 80 (odds ratio 20.6, p=0.005) and among carriers of combined heterozygous factor V Leiden and heterozygous G20210A mutation in the prothrombin gene 1 in 20 (odds ratio 88, p<0.001). The probability of thrombosis per pregnancy among women with elevated levels of factor VIII:C (>172 % activity) was 1 in 385 (odds ratio 4.5, p<0.001) and among those with increased levels of von Willebrand factor antigen (>190 %) 1 in 435 (odds ratio 4.0, p=0.002), independent of elevated factor VIII:C levels. The high prevalence of combined and homozygous defects of hemostatic components (21.6%) in patients as compared with normal women (0.86%) supports the concept that venous thromboembolism is a multicausal disorder.

Mapping of the Binding Site within Glycoprotein Ibα for the Leukocyte Integrin Mac-1 (αMβ2).

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 472-472
Author(s):  
Adam D Munday ◽  
Yuandong Peng ◽  
Yunmei Wang ◽  
Daniel I Simon ◽  
Jose A. Lopez
Keyword(s):  
Binding Site ◽  
Platelet Adhesion ◽  
Conflicts Of Interest ◽  
Peptide Binding ◽  
Von Willebrand Disease ◽  
Targeted Mutagenesis ◽  
Dimensional Structure ◽  
Monocytic Cell ◽  
Platelet Surface ◽  
Von Willebrand

Abstract Abstract 472 To maintain hemostasis, the human body uses more that 7,000 platelets/μl of blood a day; 3.5 billion platelets a day in a 70 kg adult male. Lack of fully functional platelets results in bleeding disorders such as Bernard-Soulier syndrome, Glanzmann thrombasthenia and platelet-type von Willebrand disease. It is becoming increasingly well appreciated that in addition to their hemostatic role, platelets play important roles in inflammation and wound healing. The initial step of platelet adhesion is mediated by the glycoprotein (GP) Ib-IX-V complex on the platelet surface, which binds von Willebrand factor (VWF). This interaction leads to activation of the integrin αIIbβ3, platelet arrest, and spreading and aggregation. The GPIb-IX-V complex also has a key role in inflammation, mediating a key interaction of platelets with leukocytes by binding the integrin Mac-1 (αMβ2, CD11b/CD18). This interaction mediates the firm adhesion of leukocytes on platelet thrombi, enabling their migration through the thrombus into the vessel wall. Interestingly, the insert domain (I-domain) of the αM subunit of Mac-1 has a similar 3-dimensional structure to the A1 domain of VWF. Our previous studies showed that the I-domain of Mac-1 binds the C-terminal flanking sequence of GPIbα (Phe201-Gly268), demonstrated by the ability of the anti-GPIbα monoclonal antibody AP1 to inhibit the interaction. The epitope of AP1 has been mapped to a 10-amino acid sequence spanning Arg218 to Tyr228. In the current investigation, we constructed a series of cell lines expressing mutants of human GPIbα, either by replacement of the human sequence with the corresponding dog sequence (dog GPIbα does not bind human Mac-1) or by targeted mutagenesis, and tested their ability to bind the recombinant αM I domain. TheGPIbα region Phe201–Asn223 was crucial for Mac-1 binding, with residues Arg218, Asp222 and Asn223 playing vital roles. In addition, a peptide containing the AP1 epitope (Leu214–Val229) bound αM I-domain specifically and saturably. Peptide binding was blocked by LPM19c, a monoclonal anti-αM I-domain antibody, and soluble GPIbα, and by the M2 peptide, which corresponds to the GPIbα–binding site in the αM I domain (Phe201–Lys217). Peptide binding was also blocked by an antibody against the M2 sequence. The AP1 peptide inhibited the attachment of GPIb-IX complex–expressing CHO cells to immobilized αM I domain, and the adhesion of THP-1 cells—a monocytic cell line expressing Mac-1—to immobilized GPIbα. In summary, we have defined the GPIbα sequence Arg218 to Ala224 as a critical binding site for Mac-1. Because a peptide corresponding to this region inhibits GPIbα binding to Mac-1 but blocks neither platelet adhesion to immobilized VWF nor thrombin-induced platelet aggregation, it has potential to guide the development of agents that will specifically inhibit leukocyte-platelet complexes that promote vascular inflammation. Disclosures: No relevant conflicts of interest to declare.

Hemophilia in the Peruvian Social Security System: Report of Five Centers.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4446-4446
Author(s):  
Gloria Chumpitaz ◽  
Fernando Cauvi ◽  
Juan Ramon Navarro ◽  
Karina Pedraza
Keyword(s):  
Conflicts Of Interest ◽  
Age Groups ◽  
Coagulation Factor ◽  
Von Willebrand Disease ◽  
Severe Illness ◽  
Factor Deficiency ◽  
Coagulation Factor Deficiency ◽  
Receive Treatment ◽  
New Diagnosis ◽  
Von Willebrand

Abstract Abstract 4446 The Hemophilia Unit of the Hematology Department of the National Hospital Edgardo Rebagliatti Martins- ESSALUD, is one of the most important Hemophilia Centers through the country, that assists patients not only in its jurisdiction but also a great amount referred from other institutions due the complexity of their treatment, like acquired inhibitor disorders as well as orthopedic and mayor cardiovascular surgeries and severe hemorrhages. The Hemophilia ESSALUD system is compounded of centers in Lima (02), Callao (01) and provinces (05) (Arequipa, Chiclayo, Trujillo, Piura and Cuzco). The range of patients with new diagnosis is about 5 to 20 patients per year. The prevalence of Hemophilia in the last 5 years, accounts 83.38% patients of the global amount with coagulation disorders. Of the 331 patients in treatment, 228 (68.8%) have Hemophilia A. Considering the classification of status severity, 12.5% patients of this group belong to mild status hemophilia, 39.47% patients to moderate status, and 41.43% to severe status. In relation to Hemophilia B, we account 48 (14.5%) patients; 5.2% corresponds to mild status, 23.68% moderate status and 52.63% severe status. The rest of the patients have other disorders of coagulation such as Von Willebrand disease and rare coagulation factor deficiency (V, VII, XI and XII). According to the age group distribution for this series, a mayor proportion of 44.68%of patients belong to the group between 16 to 35 years old. The group above 35 years accounts 30%.The age groups of 6 to 15 years old and the group of 1 to 5 year old account 16.48% and 8.51%, respectively. Finally, it is important to point out that 37.76% of our hemophiliac patients are in the group of moderate illness status and 44.14% in the group of severe illness status. All the patients receive treatment with plasma-derived coagulation factor concentrates and in some cases recombinant therapy. Children receive prophylactic treatment. Disclosures: No relevant conflicts of interest to declare.

ADAMTS13 In 4 Different VWF/VIII Concentrates and Its Impact on Therapy.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3677-3677
Author(s):  
Mirjeta Qorraj ◽  
Tanja Falter ◽  
Sarah Steinemann ◽  
Thomas Vigh ◽  
Inge Scharrer
Keyword(s):  
Von Willebrand Factor ◽  
Gel Electrophoresis ◽  
Conflicts Of Interest ◽  
Von Willebrand Disease ◽  
Relative Reduction ◽  
Hemorrhagic Diathesis ◽  
Adamts13 Activity ◽  
Kinetic Measurements ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Abstract 3677 Introduction: The hemostatic activity of von Willebrand Factor (VWF) is mainly controlled by the plasma metalloprotease ADAMTS13, which cleaves ultralarge VWF multimers. A qualitative or quantitative deficiency of VWF induces the most common hemorrhagic diathesis, the von Willebrand Disease (VWD). The current classification graduates the VWD in three major types. Depending on severity and the type of VWD the treatment with VWF/FVIII concentrates may by necessary. The commercially available VWF/FVIII concentrates differ in their multimer structure and furthermore also in their pharmacokinetics. We investigated commercial VWF concentrates with respect to their ADAMTS 13 activity and antigen levels with the newest available methods. Moreover, to detect a possible correlation, we analysed the VWF multimer structure of the concentrates. Methods: We analysed 4 human derived VWF/VIII-concentrates (over all 7charges) after reconstitution according to the manufacturer's instructions in different dilutions. Following methods were used: BCS Method according to Böhm detects the capacity of the concentrates for autoproteolysis. The VWF solutions were diluted with 5mol/l urea and then incubated for 14–16h at 37°C in low ionic TRIS buffer containing BaCl2 and different plasma samples: pool plasma; plasma from patients with TTP with neutralizing ADAMTS13 auto-antibodies; plasma from patients with TTP without auto-antibodies. The residual VWF:Ristocetin Cofactor (VWF:RCo) activity was subsequently measured using the BC von Willebrand Reagent from Dade Behring. ELISA Technozym®ADAMTS13 and Actifluor TM ADAMTS13 are based on the kinetic measurements of the activity with fluorescence resonance energy transfer (FRET). ADAMTS13 antigen was measured by use of the Technozym ELISA kit. SDS-Gel electrophoresis in 1% Agarose Gel was used to investigate the structure of VWF multimers. Results: The BCS Method according to Böhm is an indirect measurement for endogenous ADAMTS13 activity in the investigated concentrate. Important is the loss of the residual VWF:RCo in the concentrates in presence of TTP-plasma without antibodies and pool plasma compared to the residual VWF:RCo in presence of TTP-plasma with antibodies. All concentrates show some ADAMTS13 activity, however product 1 contains more ADAMTS13 than the other concentrates. The results of the two FRETS-assays correspond very well to the BCS-method results; in addition the assays detect directly the ADAMTS13 activity also in very low measurement range. In a dilution of 16U VWF per ml concentrate the ADAMTS13 activity in product 1 with 4.3% was the highest compared to product 2: 3.2%, product 3: 2.6% and product 4: 2%. The great variability of the test results in higher concentrations may be caused by interferences between some constituents of the concentrates and the analysis. In the same sample set and dilution the ADAMTS13 antigen values correlate very well with ADAMTS13 activity values. The SDS gel electrophoresis reveals the different VWF structure of product1; it has less large and ultralarge multimers. There could be a correlation to the relatively higher ADAMTS13 activity and antigen level. Conclusion: All the investigated VWF/VIII concentrates contain some ADAMTS13 activity and antigen. This was found especially by FRETs assay due to the high sensitivity. Because of the correlation between ADAMTS13 activity and modified VWF multimer structure we like to conclude that ADAMTS13 has influence on stability and therefore also on quality of the concentrates. This might have a therapeutic consequence especially for VWD type 2A. Type 2A is characterized by a relative reduction of intermediate and large VWF multimer. The multimeric abnormalities are commonly the result of in vivo proteolytic degradation of the von Willebrand factor caused by ADAMTS13. Disclosures: No relevant conflicts of interest to declare.

Reduced Von Willebrand Factor Secretion Is Associated with Loss of Weibel-Palade Formation

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 541-541
Author(s):  
Giancarlo Castaman ◽  
Sofia Helene Giacomelli ◽  
Paula M. Jacobi ◽  
Tobias Obser ◽  
Reinhard Schneppenheim ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Conflicts Of Interest ◽  
Negative Impact ◽  
Von Willebrand Disease ◽  
Hek293 Cells ◽  
Wild Type ◽  
And Function ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Abstract 541 Background. Von Willebrand Disease (VWD) is caused by mutations in von Willebrand factor (VWF) that have different pathophysiologic effect in causing low plasma VWF levels. Type 1 VWD includes patients with quantitative plasma VWF deficiency with normal VWF structure and function. Aim of the study. We report three different novel type 1 VWF mutations (A1716P, C2190Y and R2663C) which although located in different VWF domains are associated with reduced secretion and lack of formation of Weibel-Palade body-like granules. Methods. Transient expression of recombinant mutant full-length VWF in 293 EBNA cells was performed and secretion, collagen binding, and GpIb binding assessed in comparison to wild-type VWF. Furthermore, expression was also examined in HEK293 cells that form Weibel-Palade body (WPB)-like granules when transfected with wt VWF. Results. The multimer analysis of plasma VWF was compatible with type 1 VWD. The results of 3 different expression experiments showed a slightly reduced VWF synthesis and drastically impaired secretion into the medium with homozygous expression. In HEK293 cells, homozygous A1716P and C2190Y VWF variants failed to form WPB-like granules, while R2663C was capable of forming granules, but had fewer cells with granules and more with ER-localized VWF. Heterozygous expression of A1716P and C2160Y VWF variants had a negative impact on wild-type VWF and WPB-like granules were observed in transfected cells. Conclusions. Our results demonstrate that homozygous and heterozygous quantitative VWF deficiency caused by missense VWF mutations can be associated with inability to form endothelial Weibel-Palade-like granules and mutations in different VWF domains can affect the formation of these organelles. Disclosures: No relevant conflicts of interest to declare.

Acquired Von Willebrand Syndrome In Mitral Valve Leak

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4657-4657
Author(s):  
Almudena Pérez-Rodríguez ◽  
Maria Joana Costa Pinto Prego de Faria ◽  
Esther Lourés Fraga ◽  
Angela Rodríguez-Trillo ◽  
José Joaquín Cuenca ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Oral Anticoagulation ◽  
Conflicts Of Interest ◽  
Relative Proportion ◽  
Von Willebrand Disease ◽  
Mitral Valve Stenosis ◽  
Bleeding Diathesis ◽  
Acquired Von Willebrand Syndrome ◽  
Von Willebrand ◽  
Valve Leak

Abstract Abstract 4657 Background Several studies have shown that between 15% to 25% of patients with severe aortic stenosis present bleeding episodes that may be attributed to an acquired von Willebrand syndrome (AVWS). Until now, to our knowledge, no association of AVWS with mitral valve disfunction has been reported. Design and Methods Four patients with mitral valve leak presented acquired abnormalities of von Willebrand factor (VWF) and a bleeding history. Two of them presented severe bleedings requiring blood transfusions. All of them were within an adequate range of oral anticoagulation. Results Prior to surgery, these patients presented an APTT prolonged and in two of them the closure time determined by the platelet function analyzer (PFA-100®) (with COL/ADP and COL/Epi) was prolonged also. Factor VIII procoagulant activity (FVIII:C), VWF antigen (VWF:Ag), VWF ristocetin cofactor activity (VWF:RCo) and VWF collagen binding (VWF:CB) were considerably elevated and the VWF multimers in plasma, showed a lower relative proportion of the high molecular weight VWF multimers (HMWM), to some extent similar to type 2A congenital von Willebrand disease (VWD). In two of them, the VWF:RCo/VWF:Ag or VWF: CB/VWF:Ag ratios were less than normal range (>0.7) while in the other two were normal. After surgery, FVIII:C, and VWF properties were extremely increased and the ratios VWF:RCo/VWF:Ag and VWF: CB/VWF:Ag > 0.7. After surgery, FVIII:C, VWF:Ag, VWF:RCo and VWF:CB increased considerably. The ratios were > 0.7. The PFA-100® (COL/ADP and COL/Epi) was corrected in the two patients who had it prolonged. The multimeric VWF profile were also corrected in all of them. Conclusions The present study describes acquired VWF qualitative alterations for the first time in mitral valve leak. When such alterations are important they may be associated or to contribute to a bleeding diathesis. This problem was reported previously in aortic valve stenosis in relationship with a suspected very high shear stress. This situation may be not usually present in mitral valve stenosis, but it seems that it must occur in the presence of mitral valve leak. Consequently, the AVWS should be taken into account in patients with mitral valve leak that present a bleeding diathesis, not explained by an excess of oral anticoagulation. ACKNOWLEDGEMENTS This work was supported by the Fondo de Investigación Sanitaria, F.I.S. Carlos III, Ministerio de Sanidad, Spain (FIS PI# 07/0229), and Consellería de Innovación e Industria, Xunta de Galicia (INCITE08ENA916109ES). Disclosures: No relevant conflicts of interest to declare.

The Phenotypic Expression of Homozygous and Compound Heterozygous Factor V R506Q (Factor V Leiden, FVL) and Factor II A20210G: Ten Years Experience At a Referral Center

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 5252-5252
Author(s):  
Hamid A B Al-Mondhiry ◽  
Thomas P Nifong ◽  
Mary Elaine Eyster
Keyword(s):  
Recurrent Events ◽  
Conflicts Of Interest ◽  
Phenotypic Expression ◽  
Factor V Leiden ◽  
The Other ◽  
Compound Heterozygous ◽  
Factor V ◽  
Degree Relative ◽  
Referral Center ◽  
Factor Ii

Abstract Abstract 5252 Heterozygous Factor V Leiden, the most common inherited thrombotic disorder with an estimated incidence of about 5% in Caucasian population, poses a moderate risk of first venous thromboembolic (VTE) event. The homozygous and compound heterozygous states are comparatively rare but are thought to be associated with high risk of recurrent VTE. This report describes ten years experience with homozygous and compound heterozygous FVL and Factor II A20210G at a major referral center in central Pennsylvania, USA. Between January 2000 and December 2010, 31 homozygous F VL patients, 2 homozygous FII A20210G, 10 compound heterozygous FVL and F II A20210G and 6 compound heterozygous F VL and protein C (PC), protein S (PS) or antithrombin (AT) deficiency were encountered. The reasons for referral were personal or family history of VTE or a first degree relative diagnosed with any of these conditions. Among these patients, 5 homozygous F VL, 1 compound heterozygous F VL and F II A20210G, and 1 compound heterozygous factor VL and PC deficiency remained free of VTE at age 17–64 years, even though they were exposed to prothrombotic conditions, e.g., surgery, hormones or pregnancy. Two compound heterozygous F VL and PS deficient patients suffered ischemic strokes, one at age 3 ½ years and the other at age 45 years, but no VTE. The other patients suffered lower extremity deep vein thrombosis and/or pulmonary embolism or visceral thrombosis. Most had recurrent events. Our experience highlights the serious thrombotic risks associated with homozygous and compound heterozygous F VL and F II A20210G status but also indicates that some patients remain thrombosis free despite exposure to additional prothrombotic conditions. However, because of referral bias this series of patients may not truly reflect the overall occurrence of VTE in patients with homozygous or compound heterozygous inherited thrombophilia. Disclosures: No relevant conflicts of interest to declare.

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