Hemostatic Challenges Research Articles

G331(P) Haemophilia: a lot to learn from a near miss event

Introduction A two year old girl presented with prolonged bleeding following a fall. A strong family history of haemophilia was ignored during visits to health professionals due to the misconception that female carriers are unaffected! She was extensively investigated and was found to have Factor VIII deficiency which did not respond to Tranexamic acid and Desmopressin. This was discovered three weeks prior to her preoperative assessment for an adenotonsillectomy. Routine pre op checks, which do not always involve clotting and the above misconception, could have affected her severely perioperatively. This case highlights the importance of detailed history taking including family history and remembering that Haemophilia can, and does affect females. Case report AG was born without complication, at term by forceps delivery. Mother had heavy postpartum bleeding. She developed obstructive sleep apnoea, and adeno-tonsillectomy was planned. Three weeks before her pre-operative assessment she fell, tearing her frenulum. Persistent bleeding led to a paediatric assessment. Initial investigation revealed her haemoglobin was 88, APTT 1.5 and APTT ratio 45 and rest normal. Further investigation revealed low Factor VIIIc levels (36), 72% of expected. Other factors were normal. Detailed history taking revealed a family history of Factor VIII deficiency (maternal grandmother: carrier, maternal aunt: affected). AG received Tranexamic Acid and a Desmopressin infusion, followed by a Factor VIII infusion at the Haematology unit due to persistent bleeding. Communications between ENT a haematology is ongoing to carry out a safe surgery. Conclusion This was a near miss event which will require ongoing care from a consultant haematologist. Clinicians need to be aware that Haemophilia can, and does, affect females. 28% of female carriers of Haemophilia A are known to have Factor VIII levels consistent with mild Haemophilia. This case should raise our awareness about thorough history taking, and updating our knowledge about Haemophilia, to avoid future catastrophes. There are also important implications for her mother. We recommend checking Factor VIII activity levels in all haemophilia carriers before haemostatic challenge, such as pregnancy.

The Rate of Pregnancy Loss in Von Willebrand Disease: A Cross-Sectional Study

Pregnancy and delivery represent a major hemostatic challenge in von Willebrand disease (VWD). In addition to maintaining adequate hemostasis, von Willebrand factor (VWF) is an important regulator of angiogenesis, with angiodysplasia contributing to morbidity in patients with VWD. Placental development is complex, with vascular development important for fetal growth and viability. It has been hypothesized that antepartum bleeding or abnormal placental angiogenesis may lead to pregnancy loss in women with VWD. Large studies have reported an increased risk of postpartum bleeding in patients with VWD, however, little information is available for rates of pregnancy loss. We conducted a cross-sectional study to determine the rate of pregnancy loss in women with VWD, when compared to a control population. We invited all women with VWD followed by the Southern Alberta Rare Blood and Bleeding Disorders Comprehensive Care Program to participate in an online or paper questionnaire, along with a control group of women without VWD identified through a low-risk obstetrical clinic in Calgary, Alberta. We included patients who were 18 years of age or older with a diagnosis of VWD, defined as VWF antigen and activity levels less than 50 percent or a historical diagnosis, in combination with a bleeding score of 4 or more (condensed MCMDM-1 bleeding questionnaire). Patients were excluded if they had no past pregnancies, no mailing address, or had an alternative bleeding disorder. Our 20-item questionnaire was reviewed and pre-tested by hematologists, obstetricians and laypeople. With patient consent, data was supplemented from clinical and hospital records to verify and expand on the information collected in the questionnaire. The primary outcome was the incidence of spontaneous abortion (fetal loss <20 weeks) or late pregnancy loss (≥20 weeks) in women with VWD. The secondary outcomes were antepartum and postpartum bleeding. Data on co-morbidities including placental abnormalities were also collected. Confidence intervals for proportions were calculated using the Wilson’s score method. Groups were compared using χ2 testing, with p values < 0.05 considered significant. Of the 98 women with VWD who met the study inclusion criteria, 31 (32%) completed the questionnaire. The mean bleeding score was 10.3 in VWD patients (SD 3.6). The majority (81%) of participants were diagnosed with Type 1 VWD, with 16% and 3% diagnosed as Type 2 and 3 VWD, respectively. Twenty-two women in the control group completed the questionnaire. The mean age at recruitment was 46.1 (SD 13.7) and 32.6 (SD 4.2) in the VWD and control group, respectively. There were 83 and 48 pregnancies in the VWD and control group, respectively. Two women in the VWD group and 1 woman in the control group had an elective pregnancy termination. In women with VWD, the rate of pregnancy loss was 24.7% out of 81 pregnancies (95% confidence interval 16.6-35.1), with 17 (85%) losses occurring less than 20 weeks, and 3 (15%) with unknown timing. In contrast, the rate of pregnancy loss in the control group was 12.8% (95% CI 5.96-25.17) (p=0.106), all occurring less than 20 weeks. In 83 pregnancies, the number of antepartum bleeding episodes in VWD women was 45 (29 first trimester, 9 second trimester, 7 third trimester), compared to the control group (9 first trimester, 3 second trimester, 1 third trimester) in 48 pregnancies. More women with VWD reported excessive postpartum bleeding compared to controls (56.7% versus 13.6%, p=0.002), with more delayed (>24 hour) bleeding post-delivery in women with VWD. In VWD women with and without pregnancy loss, there was no difference in mean bleeding score (9.7 vs. 10.9). There was also no difference in cases of pre-eclampsia, placental abruption or gestational hypertension in VWD women with and without pregnancy loss. Two VWD patients with previous pregnancy loss developed gastrointestinal angiodysplasia later in life. There was no significant increase in the rate of pregnancy loss in women with VWD, however, a larger cohort study is needed to confirm the rate of pregnancy loss before further conclusions can be made. Disclosures No relevant conflicts of interest to declare.

Delivering a Hemophilic Newborn with No Intracranial Hemorrhage: Is Caesarian Section the Answer?

Birth is not only considered the first hemostatic challenge for a child with hemophilia A, but also it can result in one of the most devastating and often preventable type of bleeding in hemophilic newborns. Three to four percent of infants with hemophilia experience a head bleed at delivery. The optimal mode of delivery of the hemophilic carrier expecting an affected child is still a matter of uncertainty and debate.The aim of this study was to evaluate the frequency of major bleeding in the neonatal period and to examine the association between mode of delivery and neonatal intracranial hemorrhage (ICH) in an Arab cohort of infants with hemophilia A.Subjects and methods:A retrospective multi-center study of children with severe hemophilia A (age 0-18 years) was conducted. Five hemophilia treatment centers distributed across four Arabian Gulf countries participated in the study. Two centers from Oman and one center of each of KSA, UAE and Kuwait were included.The collected data were date of birth, maternal parity, mode of delivery, duration of labor, admission to neonatal intensive care unit, symptomatic ICH, and other bleeding episodes. Review of electronic patient record along with telephone interviews when needed were the tools used for data collection.Results:A total of 153 patients were found. Most of them were born through spontaneous vaginal delivery (SVD) (125 patients; 82 %). Vacuum extraction was adopted in six patients (4%), while twenty two patients were offered caesarian section (CS) (14%).ICH was reported in a total of four patients (2.6%). All of them were full term babies with variable time interval between the onset of the bleed and birth. One patient presented at birth, another presented at the age of 4 weeks while the remaining two had the bleed at the age of 2 weeks.Vacuum extraction was associated with the highest risk of ICH (two patients; 33 %).The other two patients were born by SVD (1.6 %). CS was not associated with ICH.Conclusions:Normal vaginal delivery is still considered a safe journey through the birth canal for hemophilic newborns. Larger prospective studies are needed to define an evidence-based optimal mode of delivery for the hemophilia carrier expecting an affected child. DisclosuresNo relevant conflicts of interest to declare.

Coagulation and placenta-mediated complications.

Pregnancy is a physiological hypercoagulable state, preparing the mother for the hemostatic challenge of delivery. However, this is associated with an increased risk of venous thrombosis and placenta-mediated complications, which present major challenges for mother and fetus. Although these conditions are heterogeneous in their pathophysiology, hereditary and acquired thrombophilia has been associated with recurrent pregnancy loss and gestational vascular complications, such as early-onset pre-eclampsia and placental abruption. Prevention of such placenta-mediated complications, which collectively complicate up to 15% of pregnancies, is a major issue for women’s health. Prospective interventional studies stratified by current knowledge of pathophysiological mechanisms related to placental and systemic hemostatic alterations will impact on the management of pregnancies at risk of these complications.

Von Willebrand Disease

Von Willebrand Disease

Point of Care Perioperative Coagulation Management in Liver Transplantation and Complete Portal Vein Thrombosis

Liver transplantation (LT) is a serious hemostatic challenge in patients with portal vein thrombosis (PVT). Advances in monitoring systems have improved surgery in this setting. We report the successful application of a point-of-care (POC) rotational viscoelastic thromboelastometry-guided (TEM) testing system (ROTEM) which allowed management of coagulation during LT in a 64-year-old cirrhotic patient with a model for end-stage liver disease (MELD) score of 16. Perioperatively, the patient showed complete PVT, hepatomegaly, splenomegaly, recanalization of the umbilical vein, and portosystemic shunt. Macroscopic liver and spleen adherences with collateral circulation were evident. Coagulation factors and fibrinolysis were assessed preoperatively and at graft reperfusion to evaluate the need of hemostatic therapy. Based on ROTEM findings, the patient received 16 g of human fibrinogen concentrate, half preoperatively (with prothrombin complex concentrate 2000 IU, tranexamic acid 1 g, and platelets 2 IU), and two doses of 4 g before and after graft reperfusion; we achieved normalization of all monitored parameters. No ischemia-reperfusion syndrome was present. Postoperatively portal vein flux at Color-Doppler ultrasonography was normal. After a 3-day ICU stay, the patient was moved to the Department of Surgery and discharged on day 14. The postoperative course was uneventful and did not require any further haemostatic therapy.

Enhancement Of Endothelial Cell Barrier Function By Antibody-Driven Affinity Modulation Of PECAM-1

Endothelial integrity is a critical parameter of hemostasis, and loss of barrier function contributes to the etiology and pathogenesis of both autoimmune and infectious disease. PECAM-1 is a cellular adhesion and signaling receptor comprised of six extracellular immunoglobulin (Ig) – like homology domains, a short transmembrane domain, and a 118 amino acid cytoplasmic domain that becomes serine and tyrosine phosphorylated upon activation. PECAM-1 is a major constituent of the endothelial cell intercellular junction, where up to 2 x 106 molecules concentrate upon cell-cell contact. Previous studies have shown that PECAM-1–PECAM-1 homophilic interactions mediated by N-terminal Ig domain 1 (IgD1) are required for border localization, and contribute importantly to steady-state endothelial cell barrier stability as well as the ability of the vascular endothelium to recover, both in vitro and in vivo, following inflammatory or hemostatic challenge. To examine whether the homophilic adhesive properties of PECAM-1 might be subject to regulation, we prepared phospholipid bilayer nanodiscs containing purified, full-length PECAM-1 and examined their ability to bind intact PECAM-1-expressing cells. Preliminary transmission electron microscopy studies indicated that PECAM-1-containing nanodiscs harbored a single, high-density refraction shadow, suggesting the presence of a single inserted PECAM-1 protein per nanodisc. Binding of these nanodiscs to either human umbilical vein endothelial cells or to PECAM-1-transfected HEK 293 cells required IgD1, as Fab fragments of the IgD1-specific monoclonal antibody (mAb), PECAM-1.3, completely blocked their binding. Interestingly, Fab fragments of mAbs PECAM-1.2 or 4G6, which bind closely-spaced epitopes within membrane-proximal IgD6, were found to enhance PECAM-1 nanodisc binding by 200-300%, suggesting that they induced a conformational change leading to a high-affinity form of PECAM-1. In support of this notion, rotary-shadowed electron micrographs of the purified PECAM-1 ectodomain revealed an ensemble of straight and bent molecular isoforms, reminiscent of conformational isomorphs that exist among members of the integrin family of adhesion receptors. Finally, to determine whether regulatable affinity modulation of this Ig superfamily member might be exploited to enhance or reinforce endothelial cell-cell borders, endothelial cell monolayer resistance was quantitatively measured using Electric Cell-substrate Impedance Sensing (ECIS), a real-time reporter of barrier function. As predicted, IgD1-specific mAb PECAM-1.3 delayed barrier recovery following thrombin-induced disruption of the endothelial cell monolayer, while IgD6-specific mAb PECAM-1.2 markedly enhanced the rate of barrier restoration. Both antibodies were without effect on endothelial cell monolayers in which PECAM-1 had been knocked down using a lentivirally-introduced PECAM-1 siRNA. Taken together, these data demonstrate that the homophilic binding affinity of PECAM-1 can be enhanced by IgD6-specific antibodies, and suggest a novel therapeutic modality for treating vascular endothelial injury-related disorders. Disclosures:No relevant conflicts of interest to declare.

The Effect Of Thrombotic Markers On The Severity Of Bleeding Symptoms In Women With Inherited Bleeding Disorders

Background Women with inherited bleeding disorders demonstrate heterogenicity in bleeding symptoms that do not always correlate to underlying clotting factor levels. This is problematic when predicting the bleeding risk, especially when haemostatic challenge is anticipated. The effect of thrombotic variables in reducing the overall bleeding tendency, have demonstrated a protective effect in cases of severe haemophilia. Aims To assess the correlation between bleeding tendency, haemostatic and thrombotic variables in women with inherited bleeding disorders. Method Quantitative measurement of the bleeding tendency was assessed using the standardized ISTH Bleeding Assessment Tool. Pictorial Blood Assessment Chart (PBAC) was used to quantify the subjective assessment of menstrual blood loss. 78 women with inherited bleeding disorders (75 with von Willebrand disease and 3 carriers of haemophilia A) were included. Blood samples were then obtained from individuals for assessment of clotting factors (factor VIII and von Willebrand factor) and thrombophilia screen (lupus anticoagulant, antithrombin, protein C and protein S, factor V Leiden mutation and prothrombin mutation). Results Bleeding score was inversely related to von Willebrand factor antigen (vWF:Ag), ristocetin cofactor (vWF:RCo) levels. A positive correlation was demonstrated with antithrombin III activity. Ten women tested positive for thrombotic markers. Multiple regression analysis did not reveal a significant correlation with presence of thrombotic marker on bleeding score. Conclusion Bleeding score is a useful assessment for bleeding phenotype and seems to correlate with vWF:Ag and vWF:RCo, which may by useful for assessment of the bleeding risk. Although there was no significant correlation demonstrated by the presence of a thrombotic marker, the levels of antithrombin III appears to affect the bleeding phenotype and this requires further consideration. Disclosures: Halimeh: Octapharma AG: Investigator Other, Research Funding.

Validation Study Of The Composite Score To Identify Von Willebrand Disease in Children

BackgroundThe diagnosis of type 1 von Willebrand disease (VWD), the most common inherited bleeding disorder, presents a diagnostic challenge in children. In the absence of a prior hemostatic challenge in children, a VWD diagnosis may be missed by the Tosetto bleeding score, as it is based, in part, on bleeding symptoms, i.e. with surgery, menses, or childbirth, that may not occur until after childhood. In fact, 25% or more of children with VWD may be diagnosed only after they experience postoperative bleeding. Other bleeding scores, such as the James score, which assesses early life bleeding, e.g. cephalohematoma, macroscopic hematuria, and umbilical stump, post-circumcision, post-venipuncture bleeding, has been validated in children with VWD, but early life bleeding events are uncommon in VWD. We previously described a 4-variable Composite Score that has 92.5% sensitivity and 95% specificity for diagnosing VWD in children < 11 years of age, when at least two of four criteria are positive: 1) Tosetto bleeding score ≥ 1; 2) family history of VWD or bleeding; 3) personal history of iron deficiency anemia; and/or 4) positive James early bleeding score. The purpose of this study was to validate a Composite Score of ≥ 2 (i.e. at least 2 of 4 variables positive) for identifying children with VWD. MethodsWe designed and conducted a prospective validation study to determine the accuracy of the Composite Score for identification of children (<11 years of age) with VWD. Following parental consent, children without a prior history of VWD undergoing VWD testing were enrolled, and survey data were collected including personal bleeding history (including Tosetto and James scores), history of iron deficiency anemia, and family history of VWD or bleeding. Results of VWD testing were collected, including VWF:RCo, VWF:Ag, and VIII:C in addition to VWF multimers, if performed. Survey data and bleeding scores were compared between those with and without VWD, defined by VWF:RCo <30 (NIH 2008 criteria), or <40, or <50 IU/dL. Prior to study, it was determined that a Composite Score ≥ 2 would have 90% power to identify VWD defined by VWF:RCo <0.30 IU/dL, and 80% power to identify VWD by VWF:RCo <40 IU/dL. Categorical variables were compared using chi-square or Fischer's exact test. Continuous variables were compared using two-sample t-test or Wilcoxon's rank sum test. Sensitivity, specificity, positive and negative predictive value of the Composite Score of ≥ 2 to diagnose VWD were determined. ResultsA total of 195 subjects were enrolled from 12 participating centers from 2010-2013, of whom 193 patients with no missing data were included in the analysis. A total of 81 (41.9%) children had type 1 VWD, including 11 (5.7%) with VWF:RCo <30 IU/dL (Group A), 24 (12.4%) with VWF:RCo <40 IU/dL (Group B), and 46 (23.8%) with VWF:RCo <50 IU/dL (Group C); the remainder with VWF:RCo ≥50 IU/dL were unaffected. There were no significant demographic differences between groups: overall 54.9% were male, 82.4% were Caucasian, and the mean age was 4.7 years. A composite score of ≥ 2 had 63.6%, 75%, and 67.4% sensitivity in diagnosing type 1 VWD in Groups A, B, and C respectively; 33.5%, 34.9%, and 34% specificity in diagnosing type 1 VWD, respectively; and 93.8%, 90.8%, and 76.9% negative predictive value, respectively. Based on the performance of the composite, with VWD being defined by a VWF:RCo of <30, <40, or <50 IU/dL, 31.6%, 30.6%, and 25.9% of subjects, respectively, had a negative composite score and therefore would not have required VWD testing. DiscussionThis is the first study to prospectively validate the Composite Score to identify children with type 1 VWD. Although the sensitivity and specificity of the Composite Score were lower than in the original study (above), the latter included only VWD subjects, while this validation study included all, VWD and non-VWD, undergoing testing. The negative predictive value of the Composite Score was robust, especially at lower VWF:RCo, and indicates that VWD testing could be eliminated in nearly a third of children referred for VWD testing. Given the difficulty of diagnosing VWD in children, the Composite Score may be an important screening tool for diagnosis of type 1 VWD in children. Disclosures:Kerlin:Bayer Healthcare US: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; NovoNordisk A/S: Consultancy, Honoraria.

Thrombin Generation Assay During Orthopaedic Surgery In Hemophilia A With and Without Inhibitors: Results From In Vivo Studies

BackgroundAlthough surgery is considered the major haemostatic challenge in patients with hemophilia, laboratory monitoring is limited to the measurement of factor VIII (FVIII) levels in response to concentrate infusions and the global effect of replacement therapy on the activation and maintenance of coagulation activation has never been investigated. Moreover, in hemophilia complicated by inhibitors no routine coagulation monitoring is available to assess haemostasis during surgery in patients receiving by-passing agents (BPA; namely, recombinant activated FVII, rFVIIa and activated prothrombin complex concentrate, aPCC). Thrombin generation assay (TGA) may be used to monitor haemostatic treatment both in inhibitor and non-inhibitor patients with hemophilia. The aims of this study were to investigate if the use of TGA in the surgical setting is able to provide information on global coagulation activation during FVIII replacement therapy and if it is related to the haemostatic and clinical response after BPA therapy in patients with inhibitors. MethodsThrombin generation was assessed in vivo in platelet-rich (PRP) and platelet-poor (PPP) plasma with the addition of corn trypsin inhibitor (CTI) in 17 patients with severe hemophilia A (9 with high-responding inhibitors) aged 5-59 years (median: 39) undergoing orthopaedic surgery at a single center. Four main parameters of the thrombin generation curve were evaluated: lagtime, endogenous thrombin potential (ETP), peak and time-to-peak. TGA was assessed once daily prior and 30 minutes after concentrate administration (FVIII or BPA) starting from the first pre-operative infusion and for at least the 4 consecutive post-operative days. Peri- and post-operative FVIII and BPA dosing and regimens were established according to our practice irrespective of TGA results. In non-inhibitor patients, FVIII levels were measured on the same blood samples drawn for TGA. ResultsIn the group of 8 non-inhibitor patients TGA values increased after the first FVIII concentrate infusion (i.e. pre-operative bolus), however during the post-operative period, when FVIII trough levels were maintained above 50 IU/dL in all patients, TGA was scarcely sensitive to the significant variation observed in FVIII levels prior (median: 74 IU/dL) and after (median: 155 IU/dL; p<0.001) FVIII daily infusions. A correlation between TGA parameters and FVIII levels was observed only for ETP and peak measured in PPP+CTI. No bleeding complication was observed in non-inhibitor patients, therefore no correlation between laboratory measurements and clinical outcome could be done. In the group of 9 inhibitor patients TGA values always increased after BPA administration however the test was not able to distinguish different haemostatic responses with respect to the type of drug (either rFVIIa or aPCC), the dose used and/or the occurrence of bleeding complications (n=5). Moreover, a lack of haemostatic response was detected by TGA over the post-operative period irrespective of treatment adjustments in all inhibitor patients. The results obtained in inhibitor patients were consistent both in PRP and PPP, with or without CTI. Finally, in both inhibitor and non-inhibitor patients TGA values after drug administration (either BPA or FVIII concentrates) were far from reaching normal values obtained in 17 healthy male controls. ConclusionsOur results indicate that TGA is not a suitable tool to monitor hemophilia treatment in the surgical setting. In fact, in non-inhibitor patients TGA was moderately sensitive to the haemostatic response to FVIII replacement therapy as compared to FVIII levels monitoring. On the other hand, in inhibitor patients TGA was not able to predict either the haemostatic response to different BPA and/or dosing regimens nor the risk of bleeding complications. Disclosures:No relevant conflicts of interest to declare.

Haemostatic challenges in the cancer patient: Focus on the perioperative period

Cancer patients are at high risk of thrombo-embolism and haemorrhage - which is exacerbated in the perioperative period. The pathogenesis of this haemostatic dysfunction is complex and involves the interplay of multiple factors. A detailed understanding of the disease pathophysiology, including mechanisms of haemostasis and laboratory assessment, is imperative in the decision making. Thrombo-embolism is an important and preventable complication of cancer surgery - with appropriate application of thromboprophylaxis. The key outstanding issues surround timing of initiation, regimen and duration of therapy. A major limitation in both our understanding and our pre-emptive management of the haemostatic dysfunction is a lack of sensitive and specific tests of haemostatic potential that can provide predictive power for risk stratification. Routine laboratory tests do not accurately recognise hyper- or hypocoagulable states, or test the clinical effects of procoagulant or anticoagulant interventions. We need further development of cellular-based assays that incorporate all the components of the haemostatic system.

Hypogranular Platelets in a 78-Year-Old Man

Patient: 78-year-old white man Chief Complaint : Abdominal aortic aneurysm with thrombocytopenia History of Present Illness: The patient has had a mildly decreased platelet count since 2004, which had become progressively lower. He had started taking a new oral hypoglycemic agent, sitagliptin phosphate (Januvia; Merck and Co, Inc, Whitehouse Station, NJ), in 2006 for his type-2 diabetes; there was speculation at the time that the decrease in platelets (Table 1) was related to the addition of this new medication to his regimen. No increased mucocutaneous bleeding was noted. No serious hemostatic challenges such as major surgery were recorded. Medical History: The patient has multiple comorbidities, including hypertension, hyperlipidemia, chronic renal insufficiency, coronary artery disease, post-myocardial infarction, atrial fibrillation, diabetes mellitus, congestive heart failure, erosive gastritis, and duodenal adenomas. Medications: The patient takes multiple medications, including warfarin sodium (Coumadin; Bristol-Myers Squibb Company, New York, NY), furosemide (Lasix; Sanofi-Aventis LLC, Paris, France), simvastatin (Zocor; Merck and Co, Inc), sitagliptin phosphate (Januvia), glimepiride (Amaryl; Sanofi-Aventis LLC), pioglitazone (Actos; Takeda Pharmaceutical Co Ltd, Osaka, Japan), lisinopril, colesevelam (Welchol; Daiichi Sankyo Co Ltd, Tokyo, Japan), and cholestyramine. Family History: No family history of abnormal bleeding or clotting is noted. Physical Examination: The patient was alert and oriented to person, place, and time without acute distress. No purpura, petechiae, or ecchymoses were observed. No lymphadenopathy, hepatomegaly, or splenomegaly was present. The patient reported no fevers, night sweats, or unexplained weight loss. The review of systems revealed no other pertinent hematologic findings. Laboratory Findings: The bone marrow was slightly to moderately hypercellular, and all 3 cell lineages were present. The bone marrow contained an adequate number of megakaryocytes with normal morphology and without clusters or dysplastic features. The immunohistochemical stain for factor VIII–related antigen helped to enhance visualization of megakaryocytes, platelets, and endothelial cells. Granulopoiesis was increased …

CHANGES OF VON WILLEBRAND FACTOR DURING PREGNANCY IN WOMEN WITHOUT AND WITH VON WILLEBRAND DISEASE

Delivery in von Willebrand disease (VWD) represents a significant hemostatic challenge because of the variable pattern of changes observed during pregnancy of von Willebrand factor (VWF) and factor VIII (FVIII), the protein carried by VWF. Since a wide heterogeneity of phenotypes and of the underlying pathophysiological mechanisms is associated with this disorder, a prompt and careful evaluation of pregnant women with VWD is requested in order to plan the most appropriate treatment at time of parturition. VWF and FVIII increase significantly during pregnancy in normal women, already within the first trimester, reaching levels by far >100 U/dL by the time of parturition. Women with VWD, levels at baseline of VWF and FVIII >30 U/dL have us a high likelihood to achieve normal levels at the end of pregnancy; thus specific anti-hemorrhagic prophylaxis is seldom required. Women with basal level <20 U/dL usually have a poor increase since most of these women carry mutations associated with increased VWF clearance or are compound heterozygous for different VWF mutations; that prevent the achievement of satisfactory hemostatic levels. While women with mutations associated with increased clearance show a full, albeit transitory correction of their hemostatic deficiency after desmopressin administration, compound heterozygous need replacement therapy because they do not respond well to this agent. Patients with abnormal VWF:RCo/VWF:Ag ratio at baseline (e.g. <0.6), typically associated with type 2 VWD, maintain the abnormality throughout pregnancy and VWF:RCo usually does not attain safe levels ≥50 U/dL. These women require replacement therapy with VWF-FVIII concentrates. Delayed post-partum bleeding may occur when replacement therapy is not continued for some days. Tranexamic acid may be useful at discharge to avoid excessive lochia.

Minimal modification in the factor VIII B-domain sequence ameliorates the murine hemophilia A phenotype

AbstractRecombinant canine B-domain deleted (BDD) factor VIII (FVIII) is predominantly expressed as a single-chain protein and exhibits greater stability after activation compared with human FVIII-BDD. We generated a novel BDD-FVIII variant (FVIII-RH) with an amino acid change at the furin cleavage site within the B domain (position R1645H) that mimics the canine sequence (HHQR vs human RHQR). Compared with human FVIII-BDD, expression of FVIII-RH protein revealed a 2.5-fold increase in the single-chain form. Notably, FVIII-RH exhibited a twofold increase in biological activity compared with FVIII-BDD, likely due to its slower dissociation of the A2-domain upon thrombin activation. Injection of FVIII-RH protein in hemophilia A (HA) mice resulted in more efficacious hemostasis following vascular injury in both the macro- and microcirculation. These findings were successfully translated to adeno-associated viral (AAV)-based liver gene transfer in HA mice. Expression of circulating FVIII-RH was approximately twofold higher compared with AAV-FVIII-BDD–injected mice. Moreover, FVIII-RH exhibits superior procoagulant effects compared with FVIII-BDD following a series of hemostatic challenges. Notably, the immunogenicity of FVIII-RH did not differ from FVIII-BDD. Thus, FVIII-RH is an attractive bioengineered molecule for improving efficacy without increased immunogenicity and may be suitable for both protein- and gene-based strategies for HA.

Is prophylaxis required for delivery in women with factor VII deficiency?

Factor VII (fVII) deficiency is a rare congenital bleeding disorder in which fVII activity level and bleeding tendency do not completely correlate. Pregnancy and delivery present a significant haemostatic challenge to women with fVII deficiency. Treatment with recombinant factor VIIa (rfVIIa) carries a thrombotic risk and the literature is not clear whether prophylaxis is necessary prior to delivery. The aim of this study was to define management, haemorrhagic and thrombotic complications of pregnant women with fVII deficiency through a systematic review. Medical databases (PubMed, MEDLINE, CINAHL, Academic Search Premier, Cochrane Library, Web of Science and Scopus) were searched using "factor VII deficiency" and "pregnancy" or "surgery." Overall 34 articles, four abstracts, and three institutional cases were reviewed. Literature from 1953 to 2011 reported 94 live births from 62 women with fVII deficiency. The median fVII activity was 5.5%. Haemostatic prophylaxis was used in 32% of deliveries. Without prophylaxis, 40 vaginal deliveries and 16 caesarean sections were completed. The odds of receiving prophylaxis were 2.9 times higher in women undergoing caesarean section compared to vaginal delivery. Post-partum haemorrhage occurred in 10% of deliveries with prophylaxis and 13% of deliveries without prophylaxis. The fVII level did not significantly differ between women who did and did not receive prophylaxis. We present the only systematic review of the management of pregnancy in fVII deficient women. No difference in post-partum haemorrhage was seen in deliveries with and without prophylaxis. Therefore, we recommend that rfVIIa be available in the case of haemorrhage or surgical intervention, but not as mandatory prophylaxis.

Newly diagnosed congenital factor VII deficiency and utilization of recombinant activated factor VII (NovoSeven&amp;reg;)

This case report presents a newly diagnosed congenital factor VII deficiency treated with recombinant activated factor VII (rFVIIa). Congenital factor VII deficiency is a rare autosomal-recessive bleeding disorder that occurs in fewer than 1/500,000 persons. Its presentation can vary from epistaxis to hemarthroses and severe central nervous system bleeding, and correlates poorly with factor VII levels. Our patient had not had a significant hemostatic challenge prior to his presentation and therefore never had any symptomatology suggestive of this disease. He was treated with rFVIIa, and was able to undergo repair of his fractures without bleeding.Case reportA 19-year-old African-American male presented to the emergency room after an altercation that resulted in significant trauma. He sustained bilateral mandibular angle fractures and orbital floor fractures, requiring urgent surgical correction. On initial evaluation, he was noted to have a prolonged prothrombin time of 40.1 seconds, with an International Normalized Ratio of 4.0, a normal activated partial thromboplastin time of 29.9 seconds, and a platelet count of 241. After receiving vitamin K and fresh frozen plasma, he was taken to the operating room for a temporary rigid maxillomandibular fixation. A 1:1 mixing study with normal plasma corrected the prothrombin time (decreasing from 40.7 to 14.7 seconds) and a factor VII assay revealed 5% of the normal factor VII level. The patient was diagnosed with congenital factor VII deficiency. Due to his coagulopathy and the extensive surgical correction needed, rFVIIa was administered and surgery was accomplished without hemorrhagic sequelae.ConclusionThis case report and review describes a rare congenital disease, the history of rFVIIa use, and its mechanism. rFVIIA use in our patient provided a treatment option that allowed the necessary surgical correction, but further prospective studies on dose optimization would ensure adequate dosing with minimal risk of severe side effects.

Hemostatic challenges in patients with chronic immune thrombocytopenia treated with eltrombopag

Chronic immune thrombocytopenia (ITP) is an autoimmune disease that results in chronically low platelet counts. Treatment guidelines recommend a platelet count of at least 50 000/µl before minor surgery and at least 80 000/µl before major surgery. This retrospective analysis explored invasive non-dental procedures associated with the risk of bleeding (hemostatic challenges) among patients with chronic ITP in five phase 2/phase 3 studies of the thrombopoietin-receptor agonist, eltrombopag. Data collection for patients who underwent hemostatic challenges included demographics, study medication, timing of the procedure, platelet counts at last assessment before and first assessment after the procedure, supplemental ITP treatment, and bleeding events. Among 494 patients who participated in the studies, 87 hemostatic challenges were recorded. Median platelet counts before 44 major procedures in 32 patients were 100 000/µl and 18 500/µl among patients who received eltrombopag and placebo, respectively; before 43 minor procedures in 38 patients, median platelet counts were 82 000/µl and 20 000/µl among patients who received eltrombopag and placebo, respectively. A minority of patients required supplemental ITP treatment. Only 2 of 87 hemostatic challenges were associated with bleeding events; both patients received eltrombopag and pre-procedural platelet counts were 83 000/µl and 2000/µl. Although the number of patients who did not undergo procedures due to thrombocytopenia was not captured, these data suggest a majority of patients with chronic ITP who receive eltrombopag and experience increases in platelet counts meet current pre-procedural platelet count recommendations. The potential role of eltrombopag in supporting preparation of chronic ITP patients for surgical procedures still needs to be clinically established.

Thrombosis in rare bleeding disorders

Inherited deficiencies of blood coagulation factors are usually associated with lifelong bleeding tendency. In addition to Hemophilias A and B and von Willebrand disease, congenital deficiencies of such factors as fibrinogen, prothrombin (FII)), FV, FVII, FX, FXI, FXIII, and combined deficiencies occur and can lead to a diversity of clinical conditions. Paradoxically, for some of these disorders associated with significant bleeding tendency there are reports of thrombotic events, both arterial and venous. Thrombosis in hemophilia patients has a multifactorial pathogenesis and the main conditions associated with this complication are the use of long-term central venous catheters, intensive replacement therapy usually in the setting of surgical procedures, the use of bypassing agents or the coexistence of acquired or inherited prothrombotic risk factors. Regarding other rare bleeding disorders, thrombotic phenomena has been described particularly in patients with afibrinogenemia, FXI and FVII deficiency and the events can occur even in young patients, in the presence of concomitant risk factors or spontaneously. Replacement therapy must be individualized and should take into account past history of haemostatic challenges, family history of bleeding and thrombosis, just like the level of factor. For mild deficiencies when patients are asymptomatic the use of antithrombotic prophylaxis must be considered with or without concomitant use of replacement therapy. In patients with history of thrombosis it may be helpful to perform a thrombophilia screening to exclude coexisting prothrombotic defects and for all patients it is recommended to control known cardiovascular disease risk factors.

A review of current methods for assessing hemostasis in vivo and introduction to a potential alternative approach

A validated method for assessing hemostasis in vivo is critical for testing the hemostatic efficacy of therapeutic agents in preclinical animal models and in patients with inherited bleeding disorders, such as von Willebrand disease (VWD) and hemophilia A, or with acquired bleeding disorders such as those resulting from medications or disease processes. In this review, we discuss current methods for assessing hemostasis in vivo and the associated challenges. We also present ARFI-Monitored Hemostatic Challenge; a new, potentially alternate method for in vivo hemostasis monitoring that is in development by our group.

Use of Desmopressin in Children With Inherited Platelet Dysfunctions Undergoing Adenotonsillar Procedures

Introduction and goalsAdenotonsillar surgery represents a major haemostatic challenge in paediatric patients with mild inherited platelet dysfunction. While there are recommendations for perioperative haemostatic management, there are no reports of the outcomes with the different recommendations in these children when undergoing adenotonsillectomy. Our objective was to evaluate the management of perioperative bleeding with desmopressin in children with mild platelet dysfunctions who underwent adenotonsillar surgery in our hospital. MethodsWe performed a retrospective study aimed at determining the perioperative bleeding and complication rate in children with mild inherited platelet dysfunction in whom desmopressin was used while undergoing adenotonsillar procedures. ResultsBetween 2004 and 2010, 27 children with mild inherited platelet dysfunction underwent adenotonsillar procedures in our hospital and were treated with desmopressin. One patient developed perioperative bleeding (3.7%) and there was 1 child (3.7%) who presented transitory hypotension as a side effect of desmopressin. ConclusionsThe use of desmopressin allowed adequate perioperative bleeding prophylaxis management in children with mild inherited platelet dysfunction who underwent adenotonsillar procedures without presenting severe complications.