ISTH Bleeding Assessment Tool Research Articles

PF334 EPIDURAL/SPINAL ANESTHESIA IN PREGNANT JEWISH ASHKENAZI WOMEN HETEROZYGOTES FOR FACTOR XI DEFICIENCY, A SINGLE CENTER PROSPECTIVE STUDY

Background:Factor XI deficiency is a rare bleeding disorder worldwide. The prevalence of heterozygous and homozygotes among Ashkenazi Jews is 8–9% and 0.22–0.53%, respectively. The severity of bleeding does not always correlate with plasma factor XI levels and many heterozygotes patients, with factor XI levels of 20–70 IU dl−1 are undiagnosed. Data regarding bleeding phenotype is scarce. Likewise, there is no consensus regarding safety of neuro‐axial anesthesia (epidural/spinal) in these women. During pregnancy, aPTT is shortened due to physiological changes of pregnancy such as elevation in factor VIII, while the level of factor XI remains stable. Thus, in Ashkenazi Jews there is no indication to test aPTT or factor XI levels before neuro‐axial anesthesia. We assume that up to 10% of the Ashkenazi Jewish women who had neuro‐axial anesthesia in our center each year undergo neuro axial anesthesia without knowing factor XI deficiency status.Aims:1. Assess the incidence of Jewish Ashkenazi women heterozygotes for factor XI deficiency who underwent neuro‐axial anesthesia in our center. 2. Asses the bleeding tendency, aPTT and thrombin generation in Jewish women of Ashkenazi descent with/without factor XI deficiency.Methods:Jewish women from Ashkenazi origin who underwent neuro‐axial anesthesia during labor in our center were recruited. After labor and signing an informed consent form, women were asked to complete the SSC ISTH bleeding assessment tool (BAT) and had blood drawn for PT, aPTT, fibrinogen, factor XI and thrombin generation. Thrombin generation was tested on a fully automated coagulation analyzer using low concentration of tissue factor 0.3pM. Reduced factor XI was defined as below 70 IU dl−1. Patients were divided according to factor XI levels; group A <70 IU dl−1 and group B ≥ 70 IU dl−1.Results:Between August 2017 and October 2018, 248 women were recruited. Of them 81% were of full Ashkenazi ethnicity. Group A included 39 (16%) women with median factor levels of 63 IU dl−1 (range: 32–69.6 IU dl−1) and group B included 209 women with a median of 96 IU dl−1 (range: 70.1–270 IU dl−1). Among group A, 20 women (51%) underwent neuro‐axial anesthesia in previous labors and 17 women (44%) underwent amniocentesis in the current pregnancy. No bleeding complications were noted in these procedures as well as in the present neuro‐axial anesthesia. Only 1 patient (group B) reported a family history of FXI deficiency. 240 women (97%) completed the BAT. There was no difference in bleeding history as reported in BAT between the 2 groups. 9 women (23%) from group A reported any bleeding complications (2 epistaxis, 1 menorrhagia, 6 postpartum hemorrhages (PPH);1 in the present labor) compared to 48 (23%) women from group B (including 13 women with PPH). Thrombin generation did not differ between the groups (Table 1). Although aPTT was within the normal range in all women, aPTT levels were significantly lower in group A compared to group B.Summary/Conclusion:A significant number of Jewish Ashkenazi women with undiagnosed partial FXI deficiency undergo neuro‐axial anesthesia. Bleeding phenotype does not differ between women with or without partial factor XI deficiency. Thrombin generation at delivery does not differ between women with or without factor XI deficiency, suggesting that hypercoagulability of pregnancy may compensate for factor XI deficiency and neuro‐axial anesthesia may be safe in these women.image

Thromboelastometry as a diagnostic tool in mild bleeding disorders: A prospective cohort study.

Major guidelines emphasise the potential of visco-elastic methods to overcome the limitations of conventional laboratory assays in the peri-operative setting. Their sensitivity regarding mild bleeding disorders (MBDs), the most common bleeding disorders in the general population, is however unknown. The aim of this study was to investigate the sensitivity of thromboelastometry for diagnosis of MBD. A single-centre prospective cohort study. Haematology outpatient unit of a tertiary general hospital in Central Switzerland. All consecutive patients referred over a 32-month period with a suspected bleeding disorder were included and thromboelastometry was conducted using a ROTEM delta (EXTEM, INTEM and FIBTEM). Diagnostic work-up was performed according to current guidelines including the ISTH bleeding assessment tool (ISTH BAT). Distribution of clotting time (CT) and maximum clot firmness (MCF) results in relation to the presence of MBD. Two hundred and seventeen patients were assessed; the median [IQR] age was 39 years [28 to 57]; 151 patients were women (70%). MBD was diagnosed in 97 patients (45%), no MBD was found in 100 patients (46%) and a systemic disorder recognised in 20 patients (9%). Presence of MBD was not associated with a significant difference in thromboelastometry variables (0.2 s in CT EXTEM, 95% CI -2.3 to 2.7; -0.2 mm in MCF EXTEM, 95% CI -1.8 to 1.5; -0.7 s in CT INTEM, 95% CI -12.6 to 11.2; 0.6 mm in MCF INTEM, 95% CI -1.2 to 1.3; 0.8 mm in MCF FIBTEM, 95% CI -1.6 to 1.4) and most results were within the established reference ranges. Our data did not support the use of thromboelastometry as a diagnostic tool in patients with MBD.

Prospective Diagnosis of VWD in a Large Cohort of Patients with Bleeding Symptoms through the Zimmerman Program

Prospective Diagnosis of VWD in a Large Cohort of Patients with Bleeding Symptoms through the Zimmerman Program

Variability in Bleeding Phenotype in Type 3 VWD Families

Type 3 von Willebrand Disease (VWD) is a rare and severe form of VWD characterized by complete absence of von Willebrand factor (VWF). Patients with type 3 VWD typically present with moderate to severe mucocutaneous bleeding as well as muscle hematomas and hemarthroses. While inheritance has classically been considered autosomal recessive, there is increasing evidence for co-dominant inheritance, with heterozygous carriers affected with low VWF levels.We sought to explore the bleeding phenotype in type 3 index cases (IC) and family members (FM) enrolled in the Zimmerman Program study using the ISTH bleeding assessment tool (ISTH-BAT), and to correlate baseline bleeding score (ISTH BS) and sequence variant (SV) location as well as analyze prospective bleeding diatheses over time using an interim bleeding score (iBAT).Analysis included type 3 VWD index cases (IC), type 3 FM, type 1 affected family members (AFM) and healthy controls (HC). Clinical laboratory phenotyping was performed at BloodCenter of Wisconsin and included FVIII, VWF:Ag, VWF:RCo, VWFpp, VWF:CB3 and multimer analysis. Genotyping involved full-length VWF sequencing, array comparative genomic hybridization to detect deletions and Fabric Genomics Opal software to determine pathological variants. Bleeding symptoms were quantified using the ISTH-BAT bleeding score where baseline scores (ISTH BS) included entire history at time of enrollment and interim bleeding scores (iBAT) that represented bleeding occurring since the initial ISTH BS was obtained. Type 3 obligate carriers (OC) were defined as either having offspring with type 3 VWD or being an offspring of an individual with type 3 VWD. Type 1 AFM cohort included subjects with type 1/low VWF who were related to a type 1 IC.The type 3 families consisted of 45 unrelated type 3 IC, 56 OC with type 1/low VWF (Type 3 OC), 23 normal unaffected OC, and 8 unaffected family members (UFM). Clinical phenotyping and study entry ISTH BS are detailed in Table 1. Type 3 OC with type 1/low VWF (n=56) had mean VWF:Ag and VWF:RCo lab values which were not different from type 1/low VWF AFM (n=483) however both FVIII (68 vs 56, p<0.001) and ISTH BS (1 vs 3, p<0.0001)were both significantly different. OC without evidence of VWD (n=23) had mean VWF:Ag (79) and FVIII (122) that was significantly different (p<0.01) from healthy controls, however there was no difference in ISTH BS.The median ISTH BS in the type 3 IC was 15, with no difference between males and females. Adults had a median ISTH BS of 18 that was significantly increased (p<0.0005) compared to a score of 11 in pediatric subjects (<18). Only 1 type 3 IC did not have an abnormal BS which was an 8 year old female.No difference in ISTH BS was observed according to number of SV or between those with or without null alleles. There was also no difference in ISTH BS (13) of IC with SV in the propeptide region compared to SV in other regions of VWF (15).The highest median baseline subscores reported were hemarthorsis (3), followed by nose bleeds (2), bruising (2), and oral cavity bleeding (2) and bleeding from minor wounds (1). 17 type 3 IC had at least one follow-up visit where median total iBAT score was 11 with most bleeding due to nosebleeds, bruising, bleeding from minor wounds and oral cavity bleeding (iBAT subscores=1).Prospective bleeding was analyzed in 12 adult type 3 IC using a baseline ISTH BS cutoff of 10 to evaluate if bleeding score would predict future bleeding. 10 subjects had ISTH BS >10 (mean age 33, BS 22) and 2 had BS<10 (mean age 33, BS 10). Those with a baseline ISTH BS >10 had a median iBAT of 13 compared to those with ISTH BS<10 with an iBAT of 6, however this was not significantly different (p=0.06) most likely due to the small number of subjects.While type 3 carriers may have low VWF levels, their bleeding is mild compared to type 1 affected family members, and not significantly different from OC with normal levels. There is a difference in type 3 index case bleeding subscores from baseline study entry compared to interim bleeding most likely reflecting the effect of treatment. In this small cohort of prospective bleeding data, the baseline bleeding score did not seem to predict future bleeding as measured by the interim bleeding score. Continued prospective studies of these patients should provide valuable insight into the variability and changes in bleeding in type 3 VWD families. [Display omitted] DisclosuresMontgomery:BCW: Patents & Royalties: GPIbM assay patent to the BloodCenter of Wisconsin.

Genotypic and Phenotypic Analysis of Adolescents with Heavy Menstrual Bleeding and Low Von Willebrand Activity - Interim Report of a Multi-Center Study

Genotypic and Phenotypic Analysis of Adolescents with Heavy Menstrual Bleeding and Low Von Willebrand Activity - Interim Report of a Multi-Center Study

Preoperative screening for bleeding disorders: A comprehensive laboratory assessment of clinical practice

Unlabelled Box BackgroundPatients with mild bleeding disorders are at risk of perioperative bleeding, but screening for these disorders remains challenging. ObjectivesWe aimed to assess the prevalence of hemostatic abnormalities in patients with and without reported bleeding symptoms on a preoperative questionnaire, consisting of guideline‐proposed questions, and appraised the diagnostic value of several screening modalities for the identification of patients with hemostatic abnormalities. MethodsIn this observational study, 240 patients with and 95 patients without bleeding symptoms on the preoperative questionnaire were included. Patients with known bleeding disorders, antithrombotic drugs, thrombocytopenia, and anemia were excluded. Preoperatively, all patients underwent elaborate hemostatic testing. Hemostatic abnormalities were defined as coagulation, vWF, or fibrinolysis factor levels below reference range and platelet function defects. Screening modalities included the ISTH Bleeding Assessment Tool (ISTH‐BAT), PT, aPTT, TT, Euglobulin Lysis Time (ELT), and Platelet Function Analyser (PFA). ResultsIn 21 of 240 (8.8%) patients reporting bleeding symptoms, hemostatic abnormalities were found, including 7 reduced coagulation factor levels, 10 platelet function abnormalities, and 4 reduced vWF levels. In comparison, 10 of 95 (10.5%) patients not reporting bleeding symptoms had abnormalities. The ISTH‐BAT could not identify patients with abnormalities, while PT, aPTT, TT, ELT, and PFA had high specificity but low sensitivity to detect abnormalities. ConclusionsThe prevalence of hemostatic abnormalities in both patients with and without reported bleeding symptoms was 9%‐10%. This suggests that the guideline‐based questionnaire cannot differentiate between patients with and without abnormalities, while the discriminative power of the screening modalities is also limited.

Patients with bleeding of unknown cause and joint hypermobility: Clinical assessment and genetic screening

Symptomatic joint hypermobiliy has been associated with bleeding tendency, suggesting that collagen disorders could be the cause in some cases of bleeding. The aim of this study was to examine the clinical characteristics of patients with bleeding tendency of unknown cause and joint hypermobility and to perform a genetic study based on Next-Generation Sequencing (NGS). This was a single-centre, prospective, observational study. Patients included were a Haemophilia Centre (HC) for bleeding symptoms of unknown cause (normal or abnormal haemostatic tests not explaining the bleeding phenotype) and having joint laxity and Musculoskeletical Rehabilitation Unit (RHB) for joint laxity and reporting bleeding symptoms. Bleeding severity was assessed by the haematologist using the ISTH Bleeding assessment tool (ISTHBAT) and joint hyperlaxity by the physiatrist by the Beighton score. Molecular analysis was performed using TruSight One Sequencing Panel Kit (Illumina). Quality and population frequency filters were applied and the search was limited to 78 genes related with Heritable Disorders of Connective Tissue (HDCT). Forty-three patients were included between June 2016 and January 207. All were females; median age was 38.6 years (range 17–62 years). Median ISTH-BAT score was 8 (range 3–17) and Beighton score 7 to 9 (range 3–9). ISTH-BAT score was abnormal in 77% and Beighton score in 80%. In 25 patients, both scores were abnormal. A total of 175 potential mutations were identified in HDCT related genes for all except one patient. In 46.5% a direct correlation between the identified mutation and the clinical phenotype could be established. In 10 patients, mutations in COL5A1 , COL5A2 , COL1A1 and COL1A2 genes were identified and validated by Sanger sequencing. Clinical assessment for symptomatic joint hypermobility should be considered in patients with significant bleeding history of unknown cause. NGS could be a useful tool for the study of the responsible genes and the classification of patients.

Common VWF sequence variants associated with higher VWF and FVIII are less frequent in subjects diagnosed with type 1 VWD

Unlabelled Box BackgroundGenetic variation in the VWF gene is associated with von Willebrand factor (VWF) and factor VIII (FVIII) levels in healthy individuals. ObjectivesWe hypothesized that VWF sequence variants associated with higher VWF or FVIII could impact the diagnosis of type 1 von Willebrand disease (VWD). MethodsWe examined VWF antigen (VWF:Ag), VWF ristocetin cofactor activity (VWF:RCo), VWF propeptide (VWFpp), and FVIII levels along with VWF gene sequencing in 256 healthy control and 97 type 1 VWD subjects as part of a cross‐sectional study. ResultsWe found several VWF sequence variants (VWF c.2880G>A and VWF c.2365A>G(;)c.2385T>C, found in linkage disequilibrium) associated with higher VWF and FVIII levels in healthy controls (P<.001 for both variants). In addition, these variants were significantly more common in controls than in subjects diagnosed with type 1 VWD and VWF:Ag <30 (P<.005). The decreased variant frequencies in type 1 VWD was not seen in other VWD types. VWF:Ag, VWF:RCo, and FVIII were not statistically different in type 1 VWD subjects who had these VWF variants compared to type 1 VWD patients without them. There was no difference in ABO blood group, VWF propeptide levels (excluding subjects with known VWF clearance defects), or bleeding score using the ISTH bleeding assessment tool. ConclusionsThese data suggest that certain VWF sequence variants associated with elevated FVIII and VWF levels may protect against reduced VWF levels. These findings were independent of other pathogenic sequence variants in VWF, suggesting a possible independent effect of c.2880G>A and c.2365A>G(;)c.2385T>C on VWF levels.

The ISTH Bleeding Assessment Tool and the risk of future bleeding

Background The ISTH Bleeding Assessment Tool (ISTH-BAT) is a diagnostic tool used in subjects with suspected inherited bleeding disorders. Aim To evaluate whether the ISTH-BAT, applied at first work-up in a tertiary-care center, predicts the risk of subsequent bleeding events. Methods This was an observational cohort study including all consecutive subjects, of either sex and any age, referred between 2011 and 2015 because of a suspected bleeding disorder. The analysis was restricted to those with an ISTH-BAT score of ≥ 3. Incidence rates (IRs) of major bleeding (MB) and clinically relevant non-major bleeding (CRNMB) events were calculated as the number of events over accrued person-years. The main analysis was performed with Cox regression analysis, assessing an ISTH-BAT score of ≤ 5 versus a score of > 5, as well as the score as a continuous variable, and various covariates (sex, age, and presence/absence of a final diagnosis). Results One hundred and thirty-six subjects had a median ISTH-BAT score of 4 (range 3-18). Eleven subjects (8.1%) had a bleeding event during follow-up (one MB event; 10 CRNMB events). The overall IR of bleeding events per 100 person-years was 3.7 (95% confidence interval [CI] 1.8-6.6). No difference was observed between subjects with an ISTH-BAT score of ≤ 5 and those with a score of > 5 (hazard ratio [HR] 1.2, 95% CI 0.3-4.6). The results were similar when the ISTH-BAT score was considered as a continuous variable (HR 1.1, 95% CI 0.9-1.4). The IR of bleeding was increased in individuals with a diagnosis of a hemostatic defect (IR of 7.5 per 100 person-years; HR 3.0, 95% CI 0.8-11.8). Conclusions The ISTH-BAT does not identify patients at increased risk of future bleeding events.

Clinical and laboratory phenotype variability in type 2M von Willebrand disease

Background von Willebrand factor (VWF) is a multimeric coagulation factor that tethers platelets to injured subendothelium. Type 2M von Willebrand disease (VWD) is characterized by a qualitative defect in VWF with preserved multimer distribution. Objectives Through the Zimmerman Program for the Molecular and Clinical Biology for VWD, five VWF sequence variations were studied in subjects diagnosed with type 2M VWD. Methods Bleeding phenotype was assessed using the ISTH bleeding assessment tool. Full-length VWF gene sequencing was performed for each subject. Each variant was placed into a recombinant VWF vector using site-directed mutagenesis and expressed in HEK293T cells as homozygous or heterozygous VWF. Variant expression, collagen binding and platelet GPIbα binding were studied through ELISA assays. Multimer analysis was performed by gel electrophoresis. Results Bleeding scores were elevated for all subjects except for the p.P1162L and p.R1374C variants. Although all had reduced VWF ristocetin cofactor activity/VWF antigen ratios on plasma testing, recombinant VWF did not show a classic type 2M phenotype for any of the five variants. Homozygous expression of variants p.D1283Y, p.R1349C, p.R1374C and p.I1453N was consistent with type 2A VWD, although all had normal expression as heterozygous recombinant VWF. Variant p.P1162L had normal VWF expression and function, consistent with the lack of bleeding symptoms. Conclusions Although originally classified as type 2M VWD, these homozygous recombinant VWF variants do not fulfill complete 2M VWD diagnostic criteria. A better classification schema and improved testing for putative type 2M variants is needed in order to effectively diagnose and treat affected patients.

Identification of Qualitative Platelet Disorders in Adolescent Women with Heavy Menstrual Bleeding

Introduction: Nearly 40% of adolescent women experience heavy menstrual bleeding (HMB), and identifiable bleeding disorders are diagnosed in only 20-60% of these patients. We suspect that qualitative platelet disorders contribute to HMB, but are under-diagnosed. A pilot study was conducted to evaluate platelet function in adolescent women with HMB employing four novel, small-volume, whole blood platelet function assays. In addition, primary and secondary hemostasis, bleeding phenotype, and quality of life were assessed.Methods: Patients referred to the Young Women’s Hematology Clinic at Oregon Health & Science University for evaluation of HMB were offered participation in the study. Participants underwent standard review of their medical and family history and physical exam. Standard lab evaluation included CBC, PT, PTT, fibrinogen, thrombin time, Von Willebrand Panel, PFA-100, and iron studies with platelet aggregation or phenotyping performed if clinically indicated. Using less than 0.5 mL of whole blood, platelet function was assessed with four novel platelet function assays: assessment of platelet activation, secretion, and aggregation was assessed by flow cytometry analysis, while platelet adhesion and aggregation was assessed under shear in a capillary tube. Quality of life (QOL) was assessed using the PedsQL tool. Bleeding phenotype was assessed with the ISTH Bleeding Assessment Tool (ISTH BAT). Menorrhagia was assessed with the Pictorial Bleeding Assessment Chart (PBAC), the Philipp Tool and the clinical history.Results: Nine participants have enrolled on study to date, with 2 completing the 3-month visit. The median age of the cohort was 16 years (14-18 years). Eight out of nine categorized their period as heavy, 6 also had epistaxis, and 7 reported excessive bruising. The median ISTH BAT score was 4 (3-7). Of the 7 patients who had a Philipp Score obtained, 5 were positive. Median PBAC score was 161 (64-196). Median ferritin was 13 ng/mL (4-65 ng/mL). Median QOL psychosocial score was 70 (68.36-88.25), comparable to that of pediatric patients with cancer. Of the 9 participants, 6 had platelet aggregation and phenotyping. Four participants did not receive a bleeding disorder diagnosis, 1 was diagnosed with Type 1 VWD, 1 was diagnosed with bleeding disorder, NOS, and 1 was diagnosed with Ehlers Danlos Syndrome. Two participants were diagnosed with a qualitative platelet disorder (QPD): one based on platelet aggregation and one based on thromboelastography. The four novel platelet function assays confirmed platelet function abnormalities in the participants diagnosed with QPD’s (Figure 1&2). Impaired platelet response to agonist stimulation was also observed in participants with non-platelet disorder bleeding disorder diagnoses and in participants without a bleeding disorder diagnosis.Conclusions: In this pilot study, the etiology of HMB in adolescent women was evaluated with four novel platelet assays in addition to standard assays of hemostasis. A bleeding disorder diagnosis was not made with standard evaluations in 4 out of 9 participants. The novel assays detected platelet abnormalities not observed using currently available clinical labs, and confirmed the presence of abnormal platelet function in participants with abnormal platelet function testing. These assays require significantly less blood volume than currently available assays and expand investigation of platelet function to platelet adhesion and platelet interactions in whole and flowing blood. Further work is needed to determine the sensitivity and specificity of the novel assays in detecting platelet dysfunction. Continued investigation into the impact of HMB on the adolescent female population is needed. [Display omitted] [Display omitted] DisclosuresHaley:CSL Behring: Honoraria; Baxalta: Membership on an entity's Board of Directors or advisory committees. Recht:Biogen: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Biogen: Research Funding; Genentech: Research Funding; Novo Nordisk: Research Funding; Baxalta: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees.

Targeted Whole Exome Sequencing of 87 Predisposition Genes in 156 Patients from the Oresund Region with Bleeding Disorders

Introduction Rare inherited bleeding disorders are a common cause of bleeding tendency. To ensure a correct diagnosis, specialized laboratory analyses are required, and the mere complexity of these investigations renders a significant part of patients without proper diagnosis. Several inherited platelet disorders are part of a syndrome, and thus a correct diagnosis may have clinical consequences, beyond genetic counseling. The aim was to report the results of up front targeted whole exome sequencing (WES).Methods Patients from the Öresund Region referred for an inherited bleeding disorder, were screened for plasma coagulation factor deficiencies and scored by ISTH Bleeding assessment tool (BAT) score. Patients with a significant BAT score and/or chronic thrombocytopenia and without evidence of a coagulation factor deficiency were included. After informed consent, blood samples for genetic screening were obtained. When genetic analysis revealed a mutation or variant of uncertain significance (VUS), further evaluation with specific functional testing and transmission electron microscopy were done, followed by a concluding multidisciplinary conference.WES and variant filtering WES was selected to identify germline mutations, as well as enabling extending the number of genes analyzed. Genomic DNA was purified from whole blood. Illumina‘s HiSeq 2500 platform was used for sequencing. The exome was covered with an average of 84x, where 97 % was covered with at least 9 x. Based on literature search, 87 genes related to bleeding, thrombocytopathia, and thrombocytopenia were analyzed. Common single-nucleotide polymorphisms were subtracted. Variant Classification:The integrated Alamut Visual software (v.2.6.1) (http://www.interactive-biosoftware.com) was used to predict the pathogenicity of specific protein variants. To designate the clinical significance, a clinical score was developed, the Öresund score, combining inheritance pattern of known diseases within the Silico based prediction. Following classification of each variant according to the five-tier scheme, patients were individually evaluated for genetic predisposition.Results 156 patients were included in the study, age 38.6±15 years (mean +/- 1SD), whereof 25 were male (16%) and 131 (84%) were female. The majority of patients had a family history of increased bleeding tendency (111 patients, 71%) and 47 patients (30%) had thrombocytopenia (a value below the normal range). The majority of patients were of European ethnicity (90%). Mean BAT score was 8 +/- 6 (1SD). A total of 421 germline mutations/variants (2.7 variant pr. patient) were found. In 28 patients (18%) a class 4-5 mutation (previously published and/or confirmed by specific functional testing) were found. In 21 patients (13%), a possible contributing class 3 VUS was found. In 21/47 patients (45%) with thrombocytopenia and 27/119 patients (23%) with normal platelet counts (p < 0.0001), a pathogenic or possibly pathogenic class 3 VUS was detected. Incidental findings occured i 3 patients (2%).Discussion and conclusion We implemented targeted WES of 87 genes up front to diagnose rare inherited bleeding disorders. In 156 patients we report the finding of 4 previously published gene mutations and 42 previously non reported mutations or class 3 VUS in 25 genes. The success rate of finding a diagnostic or possible pathogenic VUS was significantly higher in patients with thrombocytopenia. The substantial finding of additional 368 variants required clinical designation and extensive functional testing, before final classification could be made. Our finding of multiple deleterious class 3 variants in COL3A1, COL5A2 and COL5A1 warrant further investigations into the role of collagen deficiency. Only 1 patient had a (tolerated) variant in protein disulfide isomerase (P4HB), a newly discovered gene described to play a key role in initiation of clot formation. In our hands, WES was an efficient tool in defining the underlying cause of bleeding disorders. However, the large number of previously non described variants required substantial efforts to sort out. In patients with rare inherited bleeding disorders, targeted WES is a feasible method to discover possible pathogenic mutations or VUS to direct the specific functional testing. DisclosuresNo relevant conflicts of interest to declare.

Comprehensive Evaluation of Bleeding Disorders in Adolescents with Heavy Menstrual Bleeding

Introduction: Unpredictable, prolonged or heavy menstrual bleeding (HMB) is not unusual in many adolescents soon after menarche. Anovulation, owing to immaturity of the hypothalamic-pituitary-ovarian axis, is often the cause of HMB; however, it may coexist and mask an underlying bleeding disorder (BD). Retrospective data in adolescents with HMB suggest a prevalence of BDs from 10 to 62%. Prospective studies with uniform hemostatic evaluation and concurrent quality of life (QoL) assessments have not been performed. The incidence of BDs in adolescents, especially those with anovulatory bleeding, remains unknown. Methods: In this ongoing prospective cohort study (targeted n=200), 130 adolescents referred for HMB to multidisciplinary Young Women's Blood Disorders Clinics were enrolled. An assessment of menstrual loss using pictorial blood assessment chart (PBAC) and bleeding symptoms using ISTH-bleeding assessment tool (BAT) was undertaken. Participants underwent a comprehensive evaluation determined a priori, including assessment of hypermobility, standardized laboratory evaluation (prothrombin time, activated partial thromboplastin time, fibrinogen, thrombin time, von Willebrand disease (VWD) panel, whole blood platelet aggregation with ATP secretion, factor assays (FIX and FXIII), global hemostasis and hyperfibrinolysis using ROTEM, and a pelvic ultrasound (US). Patient reported outcomes for health related QoL(HR-QoL) was completed. Results: The mean age of participants was 14 (range 11-18) and mean age at menarche was 11.7 yrs. (range: 9-16). The mean PBAC score, before contraceptive initiation, was 504 (range: 100- 1200) and the mean ISTH BAT score was 3.8 (range: 1-8) in all participants. 62% had anovulatory menstrual bleeding. An inherited BD and/or bleeding risk was diagnosed in 24.6% (n=32); 9% (n=12) were diagnosed with VWD, 5% (n=6) with qualitative platelet dysfunction and 2 subjects were found to be hemophilia A (HA) carriers. Low VWF levels (VWF:Rco 30-50%) were detected in 9% (n=12). 15% had evidence of mild systemic hyperfibrinolysis (lysis 3-8% on ROTEM) but none met the criteria for further investigation for an inherited disorder of hyperfibrinolysis . Of those without BD, 2 were diagnosed to have VWF exon 28 polymorphism, and 3 were referred and ultimately diagnosed with hypermobility syndrome by Genetics. One was found to have endometriosis by laparoscopy and 3 were diagnosed with PCOS. Of those with BDs (all with low VWF), 3 were diagnosed with hypermobility syndrome (total 6) and 4 with PCOS (total 7). US was normal in all subjects. The PBAC scores were higher in BDs (634 vs. 410; SD ± 275 p=0.002), irrespective of the pattern of bleeding. No differences were found in the ISTH BAT scores (after excluding HA carriers) (3.6 vs. 4.8; SD ± 1.19, p=0.06), initial hbg or ferritin levels between the two groups. Only 6% (n=8) with BDs required ED visit and/or hospitalization for HMB vs. 14% (n=18) without a BD, of which majority had anovulatory bleeding. On multivariate logistic regression, no predictors of BDs were found. Adolescents with BDs had a decreased HR-QoL compared to those without a BD (QoL score 58 vs.87; SD± 12.5, p=&lt;0.001) even after control of HMB and correction of anemia. Conclusions: Inherited BDs are common in adolescents with HMB, confer a decreased HR-QoL and can be associated with anovulatory bleeding. A comprehensive evaluation is required to unravel disorders causing HMB. In this ongoing study, at this time, no predictor of an inherited BD was found in adolescents with HMB. Data accrual from the fully powered, ongoing, prospective study may offer further data to develop an ideal tool with a scoring system to take into account all prevalent causes of HMB to accurately predict a BD in adolescents. Disclosures Zia: NHLBI K23: Research Funding. Journeycake:CSL: Consultancy; Biogen: Consultancy; Baxalta/Shire: Consultancy. Jain:Novo Nordisk: Honoraria; Bayer: Membership on an entity's Board of Directors or advisory committees; Biogen: Speakers Bureau. Sarode:CSL Behring: Consultancy, Honoraria.

All too common: bleeding and genetic variation

Inherited bleeding disorders are both common and challenging to diagnose, particularly when the disorder is mild (reviewed in references [1, 2]). Most mild bleeding disorder patients are not routinely bleeding in their daily lives, and it can be difficult to differentiate bleeding events common in healthy populations from events which rise to the level of pathology. Fundamental to the diagnosis of bleeding disorders is a detailed assessment of the history of the patient and the family. This article is protected by copyright. All rights reserved.

Assessing Bleeding Risk in Pediatric Patients Undergoing Major Spinal Surgery

Preoperative screening for bleeding disorders in pediatric patients is problematic due to children's limited exposures to significant hemostatic challenges and the inherent difficulty in obtaining blood samples from young patients. Overcoming these challenges is of particular importance for surgical procedures that carry a significant bleeding risk, such as spinal surgeries. Many pediatric surgeons, including the Pediatric Orthopedic team at our Institution, rely on an unfocused history and measurement of general markers of hemostasis for preoperative screening. In order to improve preoperative screening of pediatric patients undergoing spinal procedures, we instituted the use of a detailed semi-quantitative questionnaire based on the ISTH Bleeding Assessment Tool (BAT), in combination with evaluation of PT, aPTT, platelet count, and PFA. The BAT gives positive points for a personal or family history of bleeding, and negative points for significant hemostatic challenges that did not result in bleeding complications. It was decided a priori that a BAT score of ≥3 would result in referral to Pediatric Hematology. A total of 212 patients presenting for major spinal surgeries (e.g., spinal fusion, growth rod placement) ranging in age from 3 to 25 years were prospectively evaluated in this fashion. A total of 41 patients (19.3%) had a prolongation of the PT and/or aPTT, none of which had a high BAT score. The majority of the abnormal PT/aPTT values were minimal prolongations that were not reproducible on repeat testing. Prolongation of the PT and/or aPTT revealed 3 patients with mild deficiencies of either factors VII, X, or XI, none of which were felt to be clinically significant. Prolonged PFAs were observed in 32 patients (16%), 1 of which was diagnosed with type I VWD (BAT score = 1), and the other with "possible VWD" based on a borderline VWF antigen level (BAT score = 0). Both were treated with Humate P. The remainder of the patients with a prolonged PFA were determined not to have a significant bleeding disorder after further testing. A total of 15 patients were referred to Hematology based on a high BAT score. Of these, 2 had a history of thrombocytopenia (1 with known DiGeorge syndrome and 1 with Depakote-related thrombocytopenia). Neither required platelet transfusion. One patient with a high BAT score was known to have type I VWD and was treated with Humate P, another was diagnosed with low expression of glycoprotein GP1b and was treated with Humate P and platelet transfusion. The remainder of the patients with high BAT scores were not felt to have a clinically significant bleeding disorder based on a Hematologist's assessment. None of the 212 patients evaluated were felt to have excessive intraoperative bleeding by the surgical team, suggesting that none of the patients had a significant undiagnosed hemostatic defect. Together, these results suggest that reliance on history or screening labs alone may not be sufficient for many pediatric surgery patients. While the PFA identified 2 patients with mild/possible VWD that would have been missed by the BAT, the PFA also had a significant number of apparent false positives. The combination of a BAT and a platelet count, as well as assessment of VWF activity for patients without previous hemostatic system challenges, may provide a more effective screening methodology for institutions with ready access to VWF activity measurement. DisclosuresNo relevant conflicts of interest to declare.

One-Stage FVIII Activity Is Inversely Correlated with Heavy Menstrual Bleeding in Hemophilia a Carriers

IntroductionThe majority of carriers of hemophilia A have historically been considered to have normal hemostasis (FVIII:C >50%) and thus not have an increased bleeding tendency. However, our research group has demonstrated that some hemophilia A carriers can experience increased bleeding compared to normal women despite this normal FVIII activity. In our recently published study in adult hemophilia A carriers there was no correlation between FVIII:C, as measured by a one-stage coagulation assay, and bleeding phenotype, as measured by the MCMDM-1 VWD bleeding score. In this follow up study we sought to determine which of these hemophilia A carriers with normal FVIII:C are at risk for bleeding. The goal of this study is to determine the relationship between FVIII assays (one-stage and chromogenic) and thrombin generation with both menstrual bleeding and an overall bleeding tendency. MethodsWe recruited mothers of children with hemophilia A in the Emory University pediatric bleeding disorders clinic. We included only adult (>18 year of age) obligate hemophilia A carriers that did not have a concomitant bleeding disorder or chronic disease that would increase their bleeding tendency. We gathered basic demographic information and evaluated the overall bleeding tendency using the ISTH Bleeding Assessment Tool (ISTH BAT), a semi-quantitative assessment of bleeding scored from 0 to 56. We considered a score of 6 or higher consistent with pathologic bleeding. In addition, we inventoried menstrual bleeding with the Pictorial Bleeding Assessment Chart (PBAC), a visual representation of menstrual blood loss. We considered a PBAC greater than 100 consistent with heavy menstrual bleeding. Plasma samples were collected from each subject at the time of the survey in sodium citrate tubes without corn trypsin inhibitor. Samples were double spun at 2,500 rpm for 15 minutes and stored at -80°C.Laboratory evaluation for each subject included FVIII:C, measured by one-stage coagulation assay (aPTT reagent with micronized silica) and chromogenic assay (COATEST SP4 FVIII kit, Chromogenix), as well as thrombin generation (Calibrated Automated Thrombogram, PPP-Reagent Low, FluCa Kit) to evaluate endogenous thrombin potential (ETP, nM*min), peak thrombin (nM) and lag time (min). We performed linear regression using GraphPad Prism; p<0.05 was considered significant. ResultsOver a three-month period, we approached 32 adult obligate hemophilia A carriers; 23 agreed to participate in the survey, 16 consented to blood draw. One carrier was excluded in extreme outlier analysis and due to an autoimmune disorder, leaving 15 evaluable subjects. Our cohort is relatively young with a median age of 41 years (range 23-51), predominantly Caucasian (53%, 8/15) and the majority carry a severe mutation (10/15 severe, 2/15 moderate, 3/15 mild).Reproductive bleeding (post-partum hemorrhage and/or menstrual bleeding) was commonly reported (93%, 14/15). The median ISTH BAT bleeding score for subjects was 2 (range 1-8). The median PBAC score was 148 (range 10-608). The carriers had a relatively normal FVIII:C by one-stage assay with a median of 0.78 U/mL (range 0.30 - 1.06) and by chromogenic assay with a median of 1.15 U/mL (range 0.66 - 1.9). FVIIIC by one-stage assay was inversely correlated to PBAC (r2 =0.4; p=0.01, figure 1A). Conversely, FVIII:C by chromogenic assay did not correlate with PBAC, however trended toward significance (r2 = 0.19; p=0.10, figure 1A). Additionally, there was no correlation found between FVIII:C (one-stage or chromogenic assay) and ISTH BAT bleeding score (figure 1B). There was also no correlation found between bleeding score or PBAC and the parameters of the thrombin generation assay or between severity of the closest male relative's hemophilia and any of the assays performed. ConclusionsIn our cohort of adult obligate hemophilia A carriers, as the FVIII:C (one-stage assay) decreased, the menstrual bleeding tendency increased as measured by the PBAC. We were unable to find a correlation between other measures of hemostasis, including the chromogenic assay and thrombin generation, and commonly used bleeding assessment tools. Further larger studies are warranted to help determine which hemophilia A carriers would be at risk for bleeding. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Value of Platelet Esoteric Testing in Laboratory Diagnosis of Platelet Disorders: A Single Center Experience

Introduction Patients with inherited and acquired platelet disorders (PD) frequently present with thrombocytopenia and/or mucocutaneous bleeding. Diagnosis of PDs relies on both clinical and laboratory investigation, which encompasses both routine and esoteric platelet testing. The former includes platelet indices, light transmission aggregation (LTA) and platelet function analyzer (PFA-100). The latter includes platelet glycoprotein (GP) assessment by flow cytometry and platelet transmission electron microscopy (PTEM). Several recent studies have demonstrated limited sensitivities of routine platelet testing. It is uncertain if a combination of both routine and esoteric testing can vastly improve the sensitivity. Our goal is to assess the value of platelet esoteric testing and the ultimate sensitivity of laboratory platelet testing in diagnosing PDs. Methods Patients (between year 2012 and 2015) with a known or suspected inherited or acquired platelet disorders were recruited for platelet routine and esoteric testing. Patients' clinical features including ISTH bleeding assessment tool (BAT) scores, platelet count, LTA, PFA-100 ADP (CADP) and epinephrine (CEPI) cartridge closure times, GP expression by flow cytometry and PTEM were performed. All clinical and laboratory variables were collected and statistically analyzed. Results A total of 69 patients (51 females; median age 40 years; range: 8 months to 76 years) were enrolled to this cohort study. By retrospective chart review, 34 patients (49%) had a positive ISTH-BAT score (range 0 to 16). The most common bleeding manifestations (on any degree of severity) were cutaneous bleeding present in 53% of patients (n=37), menorrhagia in 47% of females (n=24), epistaxis in 36% (n=25) and postoperative bleeding in 35% (n=24). Joint, muscle and CNS hemorrhage were the least frequent with 7%, 6% and 1% of patients reporting bleeding in these sites. A total of 22 patients (32%) had thrombocytopenia at the time of their evaluation. Fifty-eight patients (84%) had platelet aggregation studies and of those 15 (26%) had an abnormal study. PFA-100 was performed in 57 patients (83%) of whom 42% (n=24) had prolonged closure times with either ADP or epinephrine. PTEM was performed on all samples. Twenty-seven patients (39%) had abnormal platelet structure including 17 patients who had dense granule deficiency. GP by flow cytometry was performed in 41 patients (59%) and abnormal glycoprotein expression was detected in 6 patients (15%). Of the 55 patients who had all tests performed, 22 patients (40%) had completely normal results. Of the routine tests, only PFA-CEPI or -CADP prolongation is associated with the likelihood of a PTEM abnormality (P&lt;0.005). With the assistance of molecular testing, there were 2 cases of MYH-9 mutation-related platelet disorders, one of RUNX1 mutation-associated thrombocytopenia, one of York platelet syndrome, two of Bernard Soulier variants, one of Quebec syndrome and three of gray platelet syndrome or variants. Bleeding scores showed no statistically significant association with severity of any laboratory abnormalities. Conclusion In this cohort, the sensitivity of routine platelet testing in clinically suspected PDs is about 30-40%. Addition of platelet esoteric testing improves the sensitivity to 60%. However, the degree of platelet laboratory abnormalities do not predict severity of bleeding. The findings of this cohort underscore the importance of clinical assessment and both platelet routine and esoteric testing in investigation of patients with suspected PDs. Disclosures No relevant conflicts of interest to declare.

Evaluation of a Standardized Approach to the Diagnosis of Mild Platelet Function Defects: Recommendation for a Targeted Approach to the Diagnosis of Mild Platelet Function Defects and Identification of a Subset of Children with a "Developmental" Form

Mild platelet function defects (MPFD) are a variable group of common inherited disorders characterized by mucocutaneous bleeding and excessive bleeding with trauma, surgery and procedures. The diagnosis is often based on subjective interpretations of expensive platelet function tests that require a substantial volume of blood. Furthermore, the diagnosis of MPFD can significantly limit participation in contact sports and physically demanding careers. To explore these issues, a retrospective chart review of patients from the Comprehensive Center for Bleeding Disorders of the BloodCenter of Wisconsin with a diagnosis of MPFD, and who had at least one follow-up evaluation was undertaken. The majority of patients had been evaluated by a two-step process; initially screened with CBC, PT, PTT, TT and a von Willebrand factor (VWF) panel. If these tests were normal, platelet function was assessed with light transmission aggregometry and chemiluminesence detection of ATP release in platelet rich plasma by the agonists TRAP, arachidonic acid (0.5 nM), ADP (10 uM), collagen (2.5 ug/mL) and high and low dose ristocetin.One hundred forty-eight patients diagnosed with a primary MPFD between 1982-2014 and with at least one recorded follow-up were identified. Bleeding scores were assigned by a system incorporating principles developed for the ISTH bleeding assessment tool. Patients ranged in age from 2 months to 57 years. For assessment of age on platelet function, patients were grouped as follows: Group A <2 years (N=23), Group B 2-4 years (N=33), Group C 5-8 years (N=36), Group D 9-16 years (N=30), and group E >16 years (N=26).At diagnosis, median bleeding score was 3 (range 0-12). Bleeding scores increased with age (p<.0001); the median (range) score was 2 (0-8) for A, 2 (0-5) for B, 3 (0-9) for C, 3 (0-7) for D and 4 (0-12) for E. There was no difference in gender by age group except group E with 23 females and 1 male; twenty of the 23 females reported menorrhagia. One hundred twenty eight (86%) of the patients had abnormal ATP release (122) or platelet aggregation (6) in the presence of ADP, the most common defect identified. Of those with abnormal release of ATP, 50% had another platelet function abnormality; there was no difference in bleeding scores between those with either single or multiple abnormalities. Of those who did not have abnormal aggregation or release with ADP, 8 had an abnormal response(s) with collagen alone and 1 had abnormal ATP release with arachidonic acid alone. At the most recent follow-up visit, (median 97 months, range 1-368 ) after the initial evaluation, the interim median bleeding scores were lower; for each age group the bleeding score (range) was 2 (0-8) for A, 1 (0-6) for B, 3 (0-7) for C, 2 (0-8) for D and 3.5 (0-10) for E. When compared to the oldest group (E), groups B and D showed a statistically significant difference (p <0.05).Twenty-nine of the patients had follow-up platelet function studies; of these, 13 (all were children) had a significant decrease in bleeding score and normalization of platelet function studies. There were no differences in age, gender, or family history of bleeding between those with persistent MPFD and those with normal follow-up platelet function tests. The persistent group had higher initial (p<0.03) and follow-up (p<0.02) bleeding scores. Those with normalization had a significant decrease in bleeding scores from diagnosis to follow-up (p<0.01) while the persistent MPFD group had no difference.These results suggest that a more targeted approach utilizing the analysis of ATP release by ADP, with TRAP release to confirm the presence of granules, will identify the majority of patients with mild platelet function defects. For those with suspected MPFD and normal ATP release with ADP, a full panel of agonists followed by additional step-wise evaluation as recommended by the ISTH should be undertaken. Limiting initial platelet function testing will reduce the volume of blood required and the cost. The reassessment of platelet function studies in patients with MPFD whose bleeding symptoms subside will identify a subset of these patients with normalization of platelet function. This group will no longer require treatment for procedures and restrictions of career choices or athletic pursuits. Thus, by utilizing a standard approach, patients with MPFD can be diagnosed and managed more efficiently and effectively with less cost to both the patient and healthcare system. DisclosuresFriedman:Alexion: Speakers Bureau; Novo Nordisk: Consultancy; CSL-Behring: Consultancy; Instrumentation Laboratories: Consultancy. Flood:Baxter: Consultancy; CSL Behring: Consultancy. Jobe:Bayer: Membership on an entity's Board of Directors or advisory committees; Biogen: Membership on an entity's Board of Directors or advisory committees; CSL-Behring: Membership on an entity's Board of Directors or advisory committees. Gill:Bayer: Membership on an entity's Board of Directors or advisory committees; Baxalta: Membership on an entity's Board of Directors or advisory committees; CSL-Behring: Membership on an entity's Board of Directors or advisory committees.

Clinical features and molecular basis of 102 Chinese patients with congenital dysfibrinogenemia

IntroductionCongenital dysfibrinogenemia (CD) is a rare qualitative disorder of fibrinogen (Fg) with heterogeneous clinical manifestations. We aimed to analyze clinical phenotype and molecular basis of 102 Chinese CD patients and to evaluate the application of thromboelastography (TEG). Materials and methodsClinical manifestations were recorded and quantified using the consensus ISTH bleeding assessment tool. Kaolin activated TEG and functional Fg TEG were applied in 30 patients. Genetic analysis of Fg genes were performed by direct sequencing. Results27.5% patients experienced bleeding, 3.9% had thrombosis and 68.6% were asymptomatic. Females were more prone to experience bleeding (P=0.01). Significant difference (P<0.05) in TEG results were found between patients with hot-spot mutations at AαArg35(16) and γArg301(275), but were not identified between patients with and without bleeding. Normal TEG results were found in patients with mutations at AαArg35(16), AαPro37(18) or AαArg38(19). Six novel mutations were identified, including AαGly33(14)del, AαAsp57(38)_Trp60(41)delIVS2+1_+2GTdel, AαPhe742(723)Tyr, γAsn334(308)Thr, γGly335(309)Cys and γTrp395(369)Leu. ConclusionsCD patients have similar clinical manifestations and hot-spot mutations worldwide with no ethnic difference. TEG results could not indicate the bleeding risk in patients, but priority of mutation screening at thrombin cleavage site or polymerization site on Aа chain may be given if TEG results are normal.

Impact of Age and Gender on Bleeding Score in Type 1 VWD Using the ISTH-BAT

▪The ISTH Bleeding Assessment Tool (ISTH-BAT) was introduced in 2010 to improve on the earlier BATs and in particular to have greater accuracy in the pediatric and female population by including additional questions for neonatal bleeding and menorrhagia. The recently published cut off for positive or abnormal bleeding score (BS) is ≥ 4 in adult males, ≥ 6 in adult females and ≥ 3 in children. Here we examine the use of the ISTH-BAT in type 1 VWD and its ability to better characterize bleeding in females and children as well as the impact of menorrhagia on bleeding scores in females during aging.We analyzed 323 Index Cases (IC) and 482 Affected Family Members (AFM) enrolled in the Zimmerman Program for the Molecular and Clinical Biology of VWD (ZPMCB-VWD) with a phenotypic diagnosis of type 1 (including type 1, type 1C, type 1-severe, and low VWF). Bleeding symptoms were quantified using three different scoring systems (MCMDM-1, PBQ and ISTH-BAT), however the BS results in this analysis focus on the ISTH-BAT. Subjects were categorized by the following age groups: infant (0-2), child (3-12), adolescent (13-17), young adult (18-35), middle age (36-55), older adult (>55).Mean BS were slightly higher in both infant and child-aged males (4.5 and 4.6) compared to females (1.8 and 4.4), but the difference is not significant (p= 0.2828 and 0.5455). Higher bleeding scores in infant males were due in part to neonatal bleeding score from circumcision (13.6% of neonatal cases). The most reported bleeding symptoms in infant and child-aged males were cutaneous bleeding (61.0%), epistaxis (52.5%) and oral bleeding (25.4%). Females of this age group also presented with similar symptoms of cutaneous bleeding (64.4%), epistaxis (54.2%) and oral bleeding (30.5%).Surprisingly, there was no significant difference in total BS between adolescent males and females (mean 5.0 and 5.65, p= 0.4607). The frequency of reported bleeding symptoms in adolescent males was due to epistaxis (69.6%), cutaneous bleeding (43.5%), and minor wound bleeding (39.1%), while adolescent females reported menorrhagia (80.3%), cutaneous bleeding (65.6%), minor wound bleeding (64.4%) and epistaxis (32.8%).Bleeding symptoms reported by adults (≥18) varied by gender with males most often reporting cutaneous bleeding (50.0%), epistaxis (42.9%), oral bleeding (42.9%) and surgery (39.3%), whereas females suffered from menorrhagia (85.9%), cutaneous bleeding (80.4%), epistaxis (42.4%), minor wound bleeding (38.0%), and bleeding following tooth extractions (34.8%).Female IC (n=212) and AFM (n=280) both showed a gradual increase of BS over time (2.8 and 1.2 points per decade) whereas the BS is relatively flat over time for male IC and AFM. Analysis of female unaffected family members (n=759) showed a similar increase of BS with age (1 point per decade). To show the contribution of female specific bleeding to the overall score, we calculated a modified BS removing the menorrhagia and postpartum subscores. Interestingly, the modified BS also increased over time suggesting that other bleeding symptoms contribute to female bleeding as they age.In summary, we have shown the utility of the ISTH-BAT to characterize the bleeding in our type 1 VWD, particularly in infants and females. Infant and child-aged subjects with type 1 VWD do not show any significant difference in BS between males and females and they report similar bleeding symptoms of cutaneous bleeding, epistaxis and oral bleeding. While adolescent males and females have similar total BS, their type of bleeding symptoms vary. The BS in adult females continues to increase with age, however menorrhagia and postpartum bleeding are not the only the contributors, suggesting that there are other bleeding symptoms that account for the gradual increase of BS in females over time. DisclosuresFriedman:Alexion: Speakers Bureau; Octapharma: Consultancy; Biogen Idec: Consultancy; CSL Behring: Consultancy.