Clinical relevance of 3D gait analysis in patients with haemophilia.

Haemophilia is characterized by a congenital deficiency of clotting factor VIII or IX. One of the consequences of haemophilia is joint bleedings. Repetitive haemathroses induce cartilage damage and chronic synovitis leading to joint deterioration, and to definitive haemophilic arthropathy which is source of walking disability. Three-dimension gait analysis (3DGA) appears particularly relevant in the case of haemophilia because it allows an evaluation of several joints in weight-bearing situations. The purpose of this study was to review the interest and the contribution of 3DGA in the management of patients with haemophilia. The greatest interest of gait analysis would be to detect early walking changes with a non-invasive and well-tolerated examination, especially in paediatric population. In adulthood, this technic may be also useful to help detect walking worsening in patients known to have already arthropathy. However, it takes time to realize and needs expensive equipment, which limits its possibility of routine use. Although generalizations of these results remain difficult, especially to compare patients with haemophilia to normal population. Indeed, in the studies, patient groups are small and usually heterogeneous in terms of age and target joints. It certainly results of the rarity of the disease. So, it could be interesting to perform a study with a larger cohort in order to allow subgroup analysis, helping to define clearly the place of 3DGA in the strategy of haemophilia evaluation.

European retrospective study of real-life haemophilia treatment.

INTRODUCTION: Haemophilia treatment varies significantly between individuals, countries and regions and details of bleed rates, factor consumption and injection frequency are often not available. AIM: To provide an overview of the FVIII/FIX treatment practice and outcome for patients with haemophilia A (HA) or haemophilia B (HB) across Europe. METHODS: Non-interventional, 12-month retrospective study where anonymized data were retrieved from haemophilia centres/registers in Belgium, France, Germany, Italy, Spain, Sweden and the United Kingdom. Male patients (all ages) receiving coagulation factor treatment 24 months prior to the study, with basal FVIII/FIX levels ≤5 IU dL-1 , without inhibitors, were included. Data were summarized descriptively. RESULTS: In total, 1346 patients with HA and 312 with HB were included in the analysis; 75% and 57% had severe disease (FVIII/FIX < 1 IU dL-1 ) respectively. Prophylaxis was most common for severe haemophilia, especially for children, whereas on-demand treatment was more common for moderate haemophilia in most countries. The mean (SD) prescribed prophylactic treatment ranged from 67.9 (30.4) to 108.4 (78.1) (HA) and 32.3 (10.2) to 97.7 (32.1) (HB) IU kg-1 per week, across countries. Most patients on prophylaxis were treated ≥3 times/week (HA) or two times/week (HB). The median annual bleeding rate (ABR) for patients on prophylaxis ranged from 1.0 to 4.0 for severe HA, and from 1.0 to 6.0 for severe HB, while those with moderate haemophilia generally had slightly higher ABRs. Median ABRs for on-demand-treated severe HA ranged from 4.5 to 18.0, and for HB, 1.5 to 14.0. CONCLUSION: Treatment practice varied greatly between centres and countries and patients treated on-demand and prophylactically both experienced bleeds, emphasizing the need for further optimization of care.

Platelet function analyser (PFA-100) results and von Willebrand factor deficiency: a 16-year 'real-world' experience.

The platelet function analyser (PFA-100) is a biological tool designed to explore primary haemostasis. This system has thus been widely demonstrated as reliable in detecting von Willebrand factor (VWF) deficiency. However, most studies were based on patients benefitting from regular medical care and accurate diagnosis, and it would seem probable that the results were somewhat optimistic, and do not reflect its performances in 'real-world' situations. We have chosen to study the reliability of PFA-100 for screening VWF ristocetin cofactor (VWF:RCo) deficiency. We retrospectively analysed the results (n = 6431) of 4027 patients referred to our centre between October 1997 and June 2013 and in whom PFA-Epi, PFA-ADP, and VWF:RCo activity had been evaluated. We studied the influence of blood group on the results and the performances of each method in a subgroup of 213 patients with genetically confirmed von Willebrand disease. We have shown that the PFA-100 system, in our experience, constitutes an excellent screening test for detecting VWF:RCo deficiency, whatever the clinical situation, in 'real-world' conditions. The negative predictive value (NPV), the positive predictive value, the sensitivity and the specificity were respectively: 0.98, 0.51, 0.98 and 0.40. When values adjusted for blood group are used, NPV and sensitivity are inferior to those using normal values which have not been adjusted for blood group. We have shown the PFA-100 method to be more efficient in screening for VWF deficiency than the VWF:RCo technique.

Factor XI replacement for inherited factor XI deficiency in routine clinical practice: results of the HEMOLEVEN prospective 3-year postmarketing study.

Factor XI (FXI)-deficient patients may develop excessive bleeding after trauma or surgery. Replacement therapy should be considered in high-risk situations, especially when FXI levels are below 20 IU dL(-1) . HEMOLEVEN is a human plasma-derived factor XI concentrate available in France since 1992, but there are few data regarding its use by physicians. This prospective study assessed the use, efficacy and safety of HEMOLEVEN in common clinical practice. HEMOLEVEN was evaluated in FXI-deficient patients in 13 French centres in a 3-year postmarketing study. Forty-four patients (30 females, 14 males) received 67 treatments. The median age was 37 years (8 months-91 years). Basal FXI levels were <1 to 51 IU dL(-1) (median: 5.5); 29 patients were severely FXI-deficient (<20 IU dL(-1) ). FXI was administered prophylactically before 43 surgical procedures, 10 invasive procedures, 8 vaginal deliveries, or as curative treatment for six bleeds. The efficacy was assessed as excellent/good in 63, moderate in two and undetermined in two treatments. Seven patients experienced seven adverse effects, including two rated as serious: one sudden massive pulmonary embolism with fatal outcome and one case of inhibitor to FXI. HEMOLEVEN is effective for bleeding prevention in FXI deficiency. However, considering the benefit/risk ratio observed in relation to dosage in this study; firstly, it should be used sparingly due to its potential prothrombotic effect; secondly, new prescription procedures should be defined to adapt the dosage, especially in patients with intrinsic and/or acquired risk factors for thrombosis.

Diagnosis and management challenges in patients with mild haemophilia A and discrepant FVIII measurements.

Thirty per cent of patients with mild haemophilia A (MHA) present markedly different FVIII: C level when assayed by one-stage clotting and two-stage chromogenic assays. It is, therefore, a real clinical challenge to predict the individual bleeding risk of these patients. The aim of the present work was to study the relationship between the bleeding tendency of these patients with the results of a panel of phenotypic and genotypic tools. Thirty-six patients with MHA were included in this multicentre prospective clinical study. The severity of bleeding symptoms was evaluated using the ISTH/SSC score. FVIII:C levels were measured using an activated partial thromboplastin time-based one-stage FVIII assay (FVIII: C1) and three commercial chromogenic kits (FVIII:CR). FVIII antigen levels, thrombin generation measurement and FVIII gene mutation analysis were also performed. Our results showed that a one-stage FVIII: C assay cannot rule out the diagnosis of MHA, a combined use of FVIII:C1 with a FVIII:CR is suitable for detecting MHA. We observed that FVIII:CR results better reflected the clinical bleeding tendency of patients compared to FVIII:C1. We also observed a relationship between thrombin generation (TG) capacity and FVIII:CR of these patients. FVIII gene mutation analysis showed mutations previously reported in MHA patients with discrepant FVIII:C measurements, but with no predictive value of the individual bleeding phenotype of patients. Overall, we observed a relationship between chromogenic FVIII:C results, TG assay and bleeding tendency of patients with discrepant FVIII:C measurements, while FVIII:C1 was not well correlated with clinical bleeding phenotype in this particular population.

Management of bleeding in severe factor V deficiency with a factor V inhibitor.

Factor V (FV) inhibitor arises rarely after using fresh frozen plasma (FFP) to treat inherited FV deficiency and is often a real therapeutic challenge. Here, we report a patient with a severe FV deficiency who developed such an inhibitor and was then treated with recombinant activated FVII (rFVIIa) and platelet concentrates (PC). Monitoring was assessed by thrombin generation assay (TGA). PC were more effective than rFVIIa in treating bleeding, but there was no correlation between the TGA results and clinical efficacy.

Costs and management of patients with hemophilia A in France: the Hemraude study.

OBJECTIVE: The Hemraude study was conducted to describe the profile of patients with HA, disease management, and economic burden in a collective perspective. METHODS: This retrospective study was conducted using the French administrative healthcare claims database SNIIRAM/SNDS. Male patients treated for hemophilia A with a long-term illness (ALD) status or invalidity were included in the study between January 1, 2016 and December 31, 2017. Patients were classified in six treatment groups: no treatment, on-demand FVIII, prophylactic FVIII, FVIII in immune tolerance induction (ITI) protocol, on-demand bypassing agents, and prophylactic bypassing agents. Patients treated with FVIII in ITI protocol and those treated with bypassing agents are deemed to have developed inhibitors. HA patients were compared to a control population without coagulation disorder and matched (ratio 1:3) on age and sex. RESULTS: A total of 4172 patients were included in the analysis, aged on average 35.2 years, 5.3% had HIV infection, and 8.8% had hepatitis B or C. In 2017, half of the patients received no treatment for HA, 46.7% were treated with FVIII (25% on demand, 20.6% with prophylaxis, and 1.1% ITI), 1.5% with bypassing agents. Patients treated with prophylactic treatments, either inhibitor or non-inhibitor, were less likely to be hospitalized for severe bleeding compared to patients receiving on-demand treatments. The average annual costs for HA management per patient were 72,209.60 €. The highest costs were observed in patients treated with FVIII in ITI protocol and those receiving prophylactic bypassing agents. CONCLUSION: Direct costs of HA treatments for HA may be very high especially in the small percentage of patients developing inhibitors or treated with ITI protocol.

Validation of the first commercial ELISA for type 2N von Willebrand's disease diagnosis.

Type 2N von Willebrand's disease (VWD) is characterized by a factor VIII (FVIII) deficiency and a low FVIII/VWF ratio related to a markedly decreased affinity of von Willebrand factor (VWF) to FVIII. Type 2N VWD is diagnosed using assays allowing the measurement of plasma VWF capacity to bind FVIII (VWF:FVIIIB). These assays, crucial in order to distinguish type 2N VWD patients from mild haemophiliacs A and haemophilia A carriers, remain exclusively homemade and limited to laboratories possessing a high level of expertise in VWD. We evaluated the first commercial ELISA (Asserachrom® VWF:FVIIIB; Stago) comparated to a reference method in a multicentric study involving 205 subjects: 60 healthy volunteers, 37 haemophiliacs A, 17 haemophilia A carriers, 37 patients with type 2N VWD, 9 heterozygous carriers for a 2N mutation and 45 patients with miscellaneous other types of VWD (all previously characterized). A diluted plasma sample adjusted to 10 IU dL(-1) of VWF:Ag was incubated with a rabbit antihuman VWF polyclonal antibody. After removing the endogenous FVIII, recombinant FVIII (rFVIII) was added and bound rFVIII was quantified using a peroxydase-conjugated mouse antihuman FVIII monoclonal antibody. The intra-assay and inter-assay reproducibility was satisfactory. In all subgroups, both methods were well correlated. All type 2N VWD patients exhibited a markedly decreased VWF:FVIIIB (lower than 15%) and all heterozygous 2N carriers had a moderately decreased VWF:FVIIIB (between 30% and 65%). All controls (healthy subjects, haemophiliacs A and haemophilia A carriers) had a normal VWF:FVIIIB (higher than 80%) except one healthy volunteer and three haemophiliacs who exhibited a moderately decreased VWF:FVIIIB suggesting a heterozygous status for a 2N mutation. In conclusion, the Asserachrom® VWF:FVIIIB is easy to perform, standardized and accurate for type 2N VWD diagnosis with a 100% sensitivity and specificity.

New advances in the therapeutic and laboratory management of patients with haemophilia and inhibitors.

The management of haemophilia patients with high inhibitor titres remains a major clinical challenge. In this manuscript, we present the new developments in the treatment and laboratory monitoring of these patients. First, we discuss a general treatment algorithm to control severe bleeding episodes in these patients, established by an international panel of haemophilia specialists. The main features of this algorithm concern (i) the optimal timing of clinical and therapeutic decisions and (ii) the appropriate use of recombinant activated factor VII (rFVIIa) or activated prothrombin complex concentrates. However, until the clinical value of this algorithm is validated in real-world practice, the use of single high doses of rFVIIa should be considered as a valuable therapeutic option. Secondly, we present four laboratory assays, potential surrogate markers for the efficacy of bypassing agents used in haemophilia patients with high titre inhibitors. Preliminary data suggest that some of these tests, notably thromboelastography and the thrombin generation test, may be helpful for predicting the individual bleeding risk and for providing individually tailored treatment regimens. Overall, it may be hoped that these new developments will lead to a marked improvement in the clinical management of haemophilia patients with inhibitors in the near future.

Prospective evaluation of the '4Ts' score and particle gel immunoassay specific to heparin/PF4 for the diagnosis of heparin-induced thrombocytopenia.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a severe disease that is often difficult to diagnose. A clinical scoring system, the '4Ts' score, has been proposed to estimate its probability before laboratory testing, and a particle gel immunoassay (H/PF4 PaGIA) has also been developed for rapid detection of HIT antibodies. AIM: To evaluate the performance of both methods when HIT is suspected clinically. METHODS: Two hundred thirteen consecutive patients were included in four centers. The probability of HIT was evaluated using the 4Ts score blind to antibody test results. HIT was confirmed only when the serotonin release assay (SRA) was positive. RESULTS: The risk of HIT was evaluated by the 4Ts score as low (LowR), intermediate (IR) or high (HR) in 34.7%, 60.6% and 4.7% of patients, respectively. The negative predictive value (NPV) of the 4Ts score was 100%, as the SRA was negative in all LowR patients. PaGIA was negative in 176 patients without HIT (99.4%, NPV) and the negative likelihood ratio (LR-) was 0.05. PaGIA was positive in 37 patients, including 21 with HIT (positive predictive value = 56.8%), with a positive LR of 11.4. A negative PaGIA result decreased the probability of HIT in IR patients from 10.9% before assay to 0.6%, whereas a positive result did not substantially increase the likelihood for HIT. CONCLUSION: The use of the 4Ts score with PaGIA appears to be a reliable strategy to rule out HIT.

[Chemistry approach for therapeutic education of children with hemophilia and their parents: Representation of complex phenomena related to treatment]. / La chimie au service de l'éducation thérapeutique des enfants atteints d'hémophilie et de leurs parents : représentation de phénomènes complexes liés au traitement.

INTRODUCTION: The therapeutic management of hemophilia is based on replacement therapy by clotting factor concentrates and may require several injections per week. In teenagers, non-compliance with treatment may be responsible for major orthopedic complications. The aim of this study was to develop and assess an educational intervention for children with hemophilia and their parents, thus illustrating the complex phenomena related to treatment and its adhesion. METHODS: The construction of the educational workshop and tools was based on the concrete, visual, and playful representation of the following concepts: pathophysiology, the replacement therapy's mechanism of action, drug elimination requiring repeated administrations, and inhibitor development. The procedure was then assessed by a sample of children and parents using a questionnaire. RESULTS: A 60- to 90-min workshop was developed. The different tools used to illustrate the severity of the disease, the effect of the injected drug, drug elimination, and the inhibitor effect were: a blue-to-transparent colorimetric scale in bottles, a weekly timeline, Muppets, and a slow redox reaction. Five children and eight parents assessed this educational intervention with a rating of 3.75/4 (±0.10) and 3.60/4 (±0.45), respectively. CONCLUSION: The intervention developed could be transposed to other chronic diseases with similar therapeutic characteristics (including replacement mechanism of action and pharmacokinetics). Understanding the transmitted pharmacological concepts in a playful way is a major challenge to encourage treatment adhesion during adolescence.

Inducible production of macrophage colony-stimulating factor (CSF-1) by malignant and normal human T cells.

The CEM-ON malignant T cell line and long-term cultured normal T cells can be induced to release CSF-1 in their culture supernatants. Chemical inducers (PMA + A23187) and, more interestingly, cytokines (tumor necrosis factor alpha (TNF alpha) and interleukin-1 alpha (IL-1 alpha)), as well as physiological (antigen + IL-2) or specific (anti-CD3 + IL-2 or PMA) stimuli, lead to rapid transient colony-stimulating factor-1 (CSF-1) gene expression and production of biologically active CSF-1. These data suggest that CSF-1 may play a role in the early phases of immune response.

Molecular basis of severe factor XI deficiency in seven families from the west of France. Seven novel mutations, including an ancient Q88X mutation.

Inherited factor (F)XI deficiency is a rare disorder in the general population, though it is commonly found in individuals of Ashkenazi Jewish ancestry. In particular, two mutations--a stop mutation (type II) and a missense mutation (type III)--which are responsible for FXI deficiency, predominate. The bleeding tendency associated with plasma FXI deficiency in patients is variable, with approximately 50% of patients exhibiting excessive post-traumatic or postsurgical bleeding. In this study, we identified the molecular basis of FXI deficiency in 10 patients belonging to six unrelated families of the Nantes area in France and one family of Lebanese origin. As in Ashkenazi Jewish or in French Basque patients, we have identified a new ancient mutation in exon 4 resulting in Q88X, specific to patients from Nantes, that can result in a severely truncated polypeptide. Homozygous Q88X was found in a severely affected patient with an inhibitor to FXI and in three other unrelated families, either as homozygous, heterozygous or compound heterozygous states. Other identified mutations are two nonsense mutations in the FXI gene, in exon 7 and 15, resulting in R210X and C581X, respectively, which were identified in three families. A novel insertion in exon 3 (nucleotide 137 + G), which causes a stop codon, was characterized. Finally, sequence analysis of all 15 exons of the FXI gene revealed three missense mutations resulting in G336R and G350A (exon 10) and T575M (exon 15). Two mutations (T575M and G350A) with discrepant antigen and functional values are particularly interesting because most of the described mutations are associated with the absence of secreted protein.

Prevalence and patient profile in activated protein C resistance.

Activated protein C resistance (APC-R) is a recently defined abnormality of the coagulation system predisposing to the development of a hypercoagulable state. The authors have attempted to evaluate the prevalence and clinical manifestation of APC-R by studying a population of 183 patients with a history of venous thromboembolic episodes. Laboratory evaluation of APC-R was performed using the test initially described by Dahlbäck and colleagues based on the activated partial thromboplastin time (APTT) with the Coatest APC resistance kit (Chromogenix, Sweden) on KC10 coagulometer (Amelung, Germany). These results showed a 13% prevalence of APC-R as demonstrated by an APC ratio below 2.0. The male-to-female ratio was 1:7. Most of the thrombotic episodes were deep venous thromboses (50%).

Coagulation activation in patients with an inflammatory syndrome: is there a link with acquired protein S deficiency?

The pathogenic mechanisms of thrombosis during inflammatory syndromes are unknown. The aim of our study was to evaluate coagulation activation and fibrinolysis and to study an acquired protein S deficiency in 58 patients with an inflammatory syndrome of neoplastic (16), infectious (24) or systemic (18) origin and in 54 control subjects. The results indicated that coagulation activation, demonstrated by an increase in the prothrombin fragment 1+2, was present in patients with an inflammatory syndrome regardless of its origin. Free protein S, the only functionally active protein, was not reduced even though C4b-binding protein was increased in inflammatory syndromes. Thus, a prothrombotic state was found in inflammatory syndromes but is not explained by an acquired protein S deficiency. All except five patients had normal plasminogen activator inhibitor-1 levels.

[Hypersensitivity and resistance to antivitamins K]. / Hypersensibilité et résistance aux antivitamines K.

During the initial phase or during treatment with oral anticoagulants, hypersensitivity or resistance may be observed, requiring significant changes in prescribed dosage. A thorough knowledge of the mode of action of vitamin K and its antagonists is useful to improve understanding of unexpected response to oral anticoagulant therapy. These abnormal responses may be due to poor compliance to treatment by the patient, insufficient or excessive vitamin K intake, interference with other drugs or abnormalities of the hepatic enzymes which are the target of oral anticoagulant drugs. The search for a cause is justified by the risks associated with these abnormal responses. It must be rigorously undertaken with an accurate interrogation, use of an anticoagulation monitoring leaflet and, if necessary, measurement of plasma concentrations and pharmacokinetics of the anticoagulant drug.

[Effects of plasma substitutes on hemostasis]. / Effets des solutés de remplissage vasculaire sur l'hémostase.

OBJECTIVE: Data synthesis on haemostasis effects of cristalloids and colloids and clinical implications for their use for plasma volume replacement. DATA SOURCES: Data were searched in the Medline database from 1954 to 2000 using the following key-words: cristalloids, colloids, albumin, gelatin, dextran, hydroxyethyl starch, haemostasis, von Willebrand disease, haemodilution. DATA EXTRACTION: Publications from 1954 to 1990 were selected depending on the quality of their methodology. Most of articles published after 1990 and all types including case report were accepted. DATA SYNTHESIS: Cristalloids induces a moderate hypercoagulable state with 10 to 30% haemodilution. Hypocoagulation is observed above 50% haemodilution. Albumin does not impair hemostasis except with a 50% or more haemodilution where hypocoagulation is observed. Dextran dramatically impairs haemostasis and fibrinolysis. With increasing dose, a progressive decrease of all von Willebrand multimers, mostly the largest, is observed. Till 50% haemodilution, gelatin has a moderate impact on hemostasis, but platelet aggregation is moderately modified. However this moderate impairment of haemostasis may potentiate the haemostatic effect of other colloids when used in association with gelatin. More than 30% haemodilution with hydroxyethyl starch (HES) has a serious effect in vitro on platelet function and fibrinoformation. In most studies in human, less than 20 ml.kg-1 plasma volume replacement has no clinical impact, but in some evaluations postoperative bleeding is more important with HES, particularly HES 450, in comparison to other colloids. With HES 450 and HES 200 highly substituted (0.6 of degree of substitution) intravascular cumulation of large molecules leads to type I von Willebrand syndrome when doses overtake 80 ml.kg-1. Dextran and HES are prohibited in patients with impaired haemostasis due to congenital disease (haemophilia and von Willebrand disease) or acquired defect (thrombocytopenia). Caution is required in patients with renal failure or receiving antithrombotic or non-steroidal anti-inflammatory agents. Patients without a haemorrhagic diathesis must not received more than 1.5 g.kg-1.j-1 of dextran and restrictive conditions of use must be respected with HES. CONCLUSION: Except isotonic cristalloids, all colloids induce haemostastic changes particularly for haemodilution over 30%. Effects are more pronounced with HES and dextran.