[Willebrand factor deficiency and septorhinoplasty]. / Déficit en facteur Willebrand et septorhinoplastie.

INTRODUCTION: Willebrand disease can be diagnosed late, sometimes only when hemorrhage complicates surgery. French guidelines do not recommend investigation before surgery when no personal or familial hemorrhagic diathesis is reported. OBJECTIVE: To consider the advantages of Willebrand factor dosage before septorhinoplasty. METHOD: Three cases of septorhinoplasty and Willebrand factor deficiency complicated with hemorrhage compromising the functional result are reported. The routine tests (platelet count, bleeding time, and activated partial thromboplastin time) and Willebrand factor dosage were done before or after surgery. RESULTS: In the three cases, no personal or familiar hemorrhagic diathesis was found. For two cases, a hemorrhage occurred during surgery. One of them had prolonged and repeated nose bleedings after surgery. In this case, iterative packings damaged the result of surgery and a new rhinoplasty had to be done. In one case, a prolonged activated partial thromboplastin time before surgery revealed a Willebrand factor deficiency, leading to prophylactic treatment (desmopressin) of bleeding. CONCLUSION: The cases described suggest that systematic dosage of Willebrand factor before septorhinoplasty could be advantageous and that functional prognosis can be impaired by uncontrolled epistaxis.

Role of the leucine-rich domain of platelet GPIbalpha in correct post-translational processing--the Nancy I Bernard-Soulier mutation expressed on CHO cells.

The mechanisms governing the biosynthesis and surface expression of platelet adhesive receptors on parent megakaryocytes are as yet poorly understood. In particular, the assembly and processing of the multisubunit glycoprotein (GP) Ib-IX-V complex, a receptor for von Willebrand factor (vWf) is not fully understood. In the present work, these questions were addressed by reproducing a natural mutation of GPIbalpha found in a variant case of Bernard-Soulier syndrome (Nancy I), due to the deletion of leucine 179 in the seventh leucine-rich repeat of the polypeptide. Wild type and mutated GPIbalpha were transfected into CHO cells expressing GPlbbeta and GPIX. Flow cytometry showed surface expression of the three subunits of both GPIb-IX complexes, but GPlbalphadeltaLeu was present at lower levels (20-40%) and was recognized only by a sub class of monoclonal antibodies which epitopes were not modified by the mutation. These properties reproduce the defect found in the patient's platelets, demonstrating the causative nature of the mutation and validate the use of the CHO cells model. Biochemical studies were performed in an attempt to elucidate the mechanism of the conformational change of GPIbalphadeltaLeu. They unexpectedly revealed a major glycosylation deficiency of the mutated GPIbalpha leading to a 40% decrease in molecular weight. The other two subunits of the complex were however normal and present at the plasma membrane. The deletion led to complete functional deficiency with lack of vWf binding of CHOalphadeltaLeu transfected cells in the presence of botrocetin and defective adhesion to a vWf coated surface under static conditions. Finally, in contrast to normal CHOalphabetaIX cells, which displayed rolling and deceleration when perfused over a vWf surface, CHOalphadeltaLeubetaIX cells were unable to roll over or attach to a vWf substratum. These results show that the integrity of the leucine-rich region of GPIbalpha is essential for normal processing and function of the GPIb-IX complex. In addition, these results obtained in a cellular system supported the suspected role of the macroglycopeptide region of GPIbalpha in maintaining a suitable conformation of this multisubunit receptor to perform its adhesive function.

A cross-over pharmacokinetic study of a double viral inactivated factor IX concentrate (15 nm filtration and SD) compared to a SD factor IX concentrate.

A double blind randomized cross-over multi-center study has been conducted to compare the pharmacokinetic and coagulation activation markers of high-purity factor IX concentrate subjected to both solvent/ detergent (SD) treatment and 15 nm-filtration (FIX-SD-15) with the licensed product subjected only to solvent-detergent (FIX-SD). This filtration process allows the elimination of small particles, such as non-enveloped viruses (i.e., hepatitis A and parvovirus B19). Eleven severe hemophilia B patients (FIX coagulant activity <2 IU/dl) received one infusion of 60 IU/kg of FIX-SD and one infusion of 60 IU/kg of FIX-SD-15 at least at 10 days interval. Blood samples were obtained before and at various time up to 72 h after infusion. The decay curves of factor IX (FIX:C and FIX:Ag) were evaluated by a model independent method. Bioequivalence was found between the two concentrates using the Schuirmann test. The mean FIX:C and FIX:Ag recovery of FIX-SD-15 was 1.08 and 0.89 IU/dl/IU/kg respectively with a mean half-life of 33.3 h for FIX:C and 25.6 h for FIX:Ag. Six months after initial enrollment, pharmacokinetic parameters were similar in the 7 patients tested. There was no significant variation of prothrombin fragment 1+2 and thrombin-antithrombin complexes measured up to 6 h after infusion, indicating that there was no activation process after administration of FIX. In conclusion, these data demonstrate that the introduction of a 15 nm filtration does not alter the pharmacokinetic profile of a well characterized SD FIX concentrate while providing additional viral safety.

Analysis of biological phenotypes from 42 patients with inherited factor VII deficiency: can biological tests predict the bleeding risk?

BACKGROUND AND OBJECTIVES: Inherited factor VII (FVII) deficiency is a rare bleeding disorder characterized by a poor relationship between reported FVII clotting activity (FVII:C) and bleeding tendency. Our study was aimed at defining biological parameters that are possibly predictive for bleeding risk in this condition. DESIGN AND METHODS: Forty-two FVII-deficient patients (FVII:C <30%) were classified into two opposite clinical groups defined as severe and non-or-mild bleeders. For each patient, plasma samples were collected and then investigated for FVII:C (using a sensitive method and human recombinant thromboplastin as the reagent), FVII antigen, activated FVII coagulant activity (FVIIa:C) and the free-form of tissue factor pathway inhibitor. RESULTS: None of these tests could be used as highly accurate predictors of bleeding. Nevertheless, both FVII:C and FVIIa:C differed significantly between the two clinical groups. Using ROC-curve analysis, two critical values of 8% and 3mIU/mL for FVII:C and FVIIa:C, respectively, could be proposed to discriminate between severe bleeders and non-or-mild bleeders. INTERPRETATION AND CONCLUSIONS: A highly accurate diagnostic test for predicting bleeding tendency in inherited FVII deficiency still eludes definition, highlighting the fact that factors other than FVII itself interfere with the expression of bleeding phenotypes in this condition. Nevertheless, potential critical values using sensitive FVII:C and FVIIa:C methods may be useful in clinical laboratories for FVII-deficient patients. Those patients with FVII:C levels higher than 8% FVII:C or FVIIa:C higher than 3 mIU/mL, with no other hemostatic defect, seem to have a minimal risk of severe bleeding. Extended clinical studies are needed to support these findings.

Interferon alpha therapy in haemophilic patients with chronic hepatitis C: a French multicentre pilot study of 58 patients.

BACKGROUND AND OBJECTIVES: Information about the long-term efficacy of interferon alpha (interferon-alpha) in haemophilic patients with chronic hepatitis not co-infected with the human immunodeficiency virus (HIV-1) is still limited. Previous studies seemed to indicate a low rate of response. The aim of this study was to evaluate the safety and long-term efficacy of interferon treatment in multi-transfused haemophiliacs. METHODS: Fifty-eight haemophiliacs were scheduled to receive 3 MU of interferon-alpha 2b three times a week for 12 months. The patients were followed up for at least 24 months post-treatment. Response was assessed by measurements of serum hepatitis C virus (HCV) RNA. RESULTS: Twenty-four patients (41.4%) dropped out. Except for seven patients, the symptoms that led to interrupting interferon treatment would probably not have resulted in the same decision in non-haemophilic patients. One patient developed an inhibitor to the deficient clotting factor without haemorrhagic consequences. In an intent to treat, the sustained virological response rate was 14%. However, when considering only the 34 patients who received the full treatment, HCV-RNA was cleared in eight patients (23%). CONCLUSIONS: This study suggests that multi-transfused haemophiliacs with chronic hepatitis not co-infected with HIV-1 respond to prolonged treatment with interferon-alpha in a similar proportion to that observed in non-haemophiliacs. There was a high rate of patients who did not complete the interferon-alpha treatment, and this seems to be characteristic of this patient population.

Experiences with continuous infusion of recombinant activated factor VII.

A questionnaire was sent to 28 haemophilia treatment centres known to have used recombinant activated factor VII (rFVIIa; NovoSeven, Novo Nordisk, Bagsvaerd, Denmark), to collect data on continuous infusion of this product. This mode of administration was recently introduced for rFVIIa but there are several questions which remain to be answered in order to optimize this technique. Of the 26 responding centres, 14 had used rFVIIa in continuous infusion for 40 treatment episodes over a total of 283 days. In most of the cases the treatment was targeted at a factor VII level of 10 IU/ml, monitored by the one-stage clotting assay. This seemed to be adequate for most of the haemorrhagic and surgical procedures. Pretreatment pharmacokinetic evaluation was performed in only a minority of the cases but is probably of great importance given the wide variation observed in the clearance values. A strategy was necessary to prevent local thrombophlebitis, at least for infusions in peripheral veins; parallel infusion of heparin, saline or dextrose-saline proved effective. The question of optimal monitoring needs further attention. Haemorrhagic complications were significantly less frequent when treatment was combined with the antifibrinolytic tranexamic acid.

[Is enoxaparine (PK 10169) a good anticoagulant in chronic hemodialysis?]. / L'énoxaparine (PK 10,169) est-elle un bon anticoagulant dans l'hémodialyse itérative?

Tolerance and efficacy of single i. v. injections of PK 10169 (1 mg/kg) during installation were evaluated in 10 patients with stable chronic renal insufficiency treated with 3 sessions of hemodialysis weekly (sessions of 4 and 5 hours). Tolerance was good in all cases. Efficacy was globally satisfactory (no complete coagulation) but by the 4th hour in 7 out of 30 sessions coagulation was apparent in the bubble trap with elevation of residual blood volume, recurring in the same patient but not affecting result of dialysis. In these cases anti-Xa activity was reduced from the 2nd hour and at end of dialysis, with a markedly elevated FPA level. For most patients it is possible to envisage 5-hour sessions, but in those few susceptible to develop coagulation repeated clinical surveillance of all circuit elements is necessary.

[Thrombogenic thrombopenia related to heparin. Clinical, biological and therapeutic results. Apropos of 32 cases]. / Thrombopénies thrombogéniques liées à l'héparine. Résultats cliniques, biologiques et thérapeutiques. A propos de 32 cas.

Heparin induced thrombocytopenia is characterized by often dramatic evolution of thrombotic arterial and venous complications. These occurred or are worsened in curative or preventive heparin therapy and the treatment remains delicate. The authors report 32 observations of thrombocytopenia complicated with thromboembolic events; seven deaths are to mention. The tests of platelet aggregation with standard heparin and platelets poor patient's plasma confirm the diagnosis in 28 cases of 30 very early studied and in 2 cases around the 6th day only after the stop of standard heparin. The choice of anticoagulant therapy is carried out the negative tests of platelet aggregation with low molecular weight heparin (L.M.W.H.) (CY 216, CY 222 Choay, PK 10109 Pharmuka). In L.M.W. heparin therapy, clinical and biological improvement is obtained in 26 cases of 30 treated cases. In three cases, the rapid climbing of platelet countings is not present although negative tests of platelet aggregation with selected L.M.W.H. In one case, after a initial climbing of platelet countings, the thrombocytopenia recurs rapidly with L.M.W. heparin after a operation. The immediate or secondary passage with K-antivitamins, platelet antiaggregant stabilized medium and long term's evolution.

[Role of the hemostasis laboratory in the etiologic approach to deep vein thrombosis]. / Place du laboratoire d'hémostase dans la démarche étiologique des thromboses veineuses profondes.

Thrombophilia is characterized by an inherited or acquired defect in the blood coagulation pathway leading to an increased risk for thrombosis. The etiological approach following confirmed venous thrombotic events should rule out medical or chirurgical risk factors. Thrombophilia should be sought by laboratory tests. The recent discovery of a blood coagulation defect: inherited resistance to activated protein C which is found to 20% of patients with former thrombotic events has changed current laboratory approach. Deficiencies of one of the anticoagulant proteins (antithrombin III, protein C, protein S) are found in 10% of the patients, similar to the frequency of antiphospholipid antibodies. These tests may be difficult to interpret immediately after the thrombotic event because of various factors such as inflammatory states or anticoagulant treatments. Therefore this abnormal tests should be confirmed on a later sample analysis far from the event. The discovery of an inherited blood coagulation pathway defect may affect the duration of treatment, prophylaxis in situations with circumstantial risk factors and requires familial analysis. Inherited resistance to activated protein C may be associated with another inherited defect leading to an increased risk for thrombosis.

[Multicenter study on purified protein C concentrates and defined plasma levels]. / Etude multicentrique sur les dosages de concentrés de protéine C purifiée et de plasmas à taux définis.

A variety of protein C assays are available as commercial kits. A collaborative study was undertaken to evaluate the performance of protein C assays. Various samples including calibrated plasmas and high purity concentrates destined to therapy were distributed among five laboratories. This comparison of protein C assays indicates that protein C levels measured by different functional or immunological assays and by five laboratories are very close for calibrated plasmas but not for high purity concentrates. The selection of the standard and the dilution buffer for protein C concentrates have important implications for the interpretation of the results. Dilution of purified protein C concentrates in protein C deficient plasma which restaure a total protein level similar to that of normal plasma improve the accuracy of functional protein C assays.

[Heparin-induced thrombopenia]. / Thrombopénie induite par l'héparine.

Heparin-induced thrombocytopenia remains a topical subject for at least two reasons. The first reason is the increasing prescription of low molecular weight heparins (LMWH) rather than unfractionated heparins, with limited laboratory surveillance, raising the question concerning the need for twice-weekly platelet counts, according to the recommendations of the Vidal drug directory. The second reason is the recent release onto the market of two products, danaparoid (Orgaran) and lepirudin (Refludin) for this precise indication of heparin-induced thrombocytopenia. These products greatly facilitate the management of this complication. Many basic research teams are trying to optimize the detection of heparin-dependent antibodies and to more clearly elucidate the mechanism of this particular thrombocytopenia, which carries a risk of very severe thrombotic complications when the diagnosis is delayed.

[Surgery and the acquired inhibitor of factor VIII coagulant]. / Chirurgie et inhibiteur acquis du facteur VIII coagulant.

A case is reported of an 80 year old woman with old sarcoidosis and acquired factor VIIIc inhibitor undergoing orthopaedic surgery. This was successfully carried out after she had been given a total of 48,420 units of factor VIII concentrate: there were no haemorrhagic complications. The main pathological states in which acquired factor VIIIc inhibitor may be found are related: principal treatments available nowadays are discussed: immunosuppressors, human factor VIII, animal factor VIII, prothrombin complex concentrate, plasma exchange.

[Development of antifactor VIII circulating anticoagulant after surgery of the biliary tract]. / Apparition d'un anticoagulant circulant antifacteur VIII après chirurgie de la voie biliare.

In a 25-year-old woman, admitted with a haemorrhagic syndrome following biliary surgery, an inhibitor of factor VIII was detected. As bleeding was major, she was re-operated on under perioperative administration of the anti-inhibitory coagulant complex Autoplex-T, associated with polyvalent i.v. immunoglobulins. The other therapeutic agents are also considered and their indications discussed, after a review of the circumstances of the diagnosis of this disease.

[Which assessment of coagulation, for which operation?]. / Quel bilan de la coagulation, pour quel opéré?

Patient's bleeding history is an important part of preoperative evaluation but must be associated with hemostatic tests. The choice in between these different hemostatic tests will be made according to the knowledge of the bleeding history and; the type of surgery planned. In case of hemostatic abnormality, additional tests can be performed in order to determine a more precise state of the patient's hemostatic dysfunction. However, complete preoperative hemostatic evaluation (including patient's bleeding history and blood tests) may not entirely avoid per and post-operative hemostatic complications. Indeed, there is no absolute correlation between hemostatic screening and bleeding or thrombosis risks. Some other factors, completely independent from hemostatic function, such as shock, surgical bleeding, anoxia... may intervene.

Implementation of a hepatitis A prevention policy in haemophiliacs: results from the French cohort.

In the early nineties, the occurrence of hepatitis A outbreaks in some patients with haemophilia in some countries led French health authorities to recommend hepatitis A virus (HAV) vaccination in HAV-seronegative haemophiliacs. The French 'Suivi thérapeutique National des Hémophiles' cohort permitted to assess the implementation of this recommendation by the analysis of the vaccinal process, i.e. HAV seropositivity assessment and vaccination of HAV-seronegative patients, in a survival approach. In a subgroup of 812 patients diagnosed earlier than 1990 (prevalent cohort), the implementation of vaccinal process increased quickly from 0% in 1993 to 41.8% in 1994 and to 71.2% in 1996, suggesting a 'notification effect'. The vaccinal process was associated to three cofactors in a Cox model analysis (age, severity of haemophilia, centre of treatment). No infection was observed during the survey in this group. In another subgroup of 201 boys born since 1993 (incident cohort), 27.5% and 15.4% patients remained exposed to the risk at 3 and 5 years from diagnosis respectively, again with a 'centre effect', which might be linked to various factors such as regain in confidence for products or economic reasons. Only five infectious seroconversions were assessed over the 7-year survey, which represents 14.5 cases per 1000 person-year incidence without any relationship with products. Our data combined with the contemporary hepatitis A epidemiology and the current safety of anti-haemophilic concentrates, should lead to a new assessment of the risk of hepatitis A in haemophiliacs. We suggest that among patients with bleeding disorder, as well as in other populations, HAV prevention policy might be stressed on those who already suffer from chronic liver disease and/or travel in endemic countries.