Diagnosing Czech Patients with Inherited Platelet Disorders.

A single-center study was conducted on 120 patients with inherited disorders of primary hemostasis followed at our hematological center. These patients presented a variety of bleeding symptoms; however, they had no definitive diagnosis. Establishing a diagnosis has consequences for the investigation of probands in families and for treatment management; therefore, we aimed to improve the diagnosis rate in these patients by implementing advanced diagnostic methods. According to the accepted international guidelines at the time of study, we investigated platelet morphology, platelet function assay, light-transmission aggregometry, and flow cytometry. Using only these methods, we were unable to make a definitive diagnosis for most of our patients. However, next-generation sequencing (NGS), which was applied in 31 patients, allowed us to establish definitive diagnoses in six cases (variants in ANKRD26, ITGA2B, and F8) and helped us to identify suspected variants (NBEAL2, F2, BLOC1S6, AP3D1, GP1BB, ANO6, CD36, and ITGB3) and new suspected variants (GFI1B, FGA, GP1BA, and ITGA2B) in 11 patients. The role of NGS in patients with suspicious bleeding symptoms is growing and it changes the diagnostic algorithm. The greatest disadvantage of NGS, aside from the cost, is the occurrence of gene variants of uncertain significance.

Hereditary antithrombin deficiency in pregnancy - severe thrombophilic disorder as a danger for mother and foetus

SETTING: In the article, we remember the role of antithrombin (AT) in hemostasis, escalation of AT-potential with heparin and difficulties with monitoring the effectiveness of LMWH therapy (low molecular weight heparin) in patients with AT deficiency. We pay most of our attention to hereditary AT deficiency and its thromboembolic risk in pregnancy. METHODS: In the introduction, the principle of AT function, its two main domains and the regulation of synthesis are cleared. We describe the causal mutations of hereditary AT deficiency in SERPINC1 gen and the relation to a thromboembolic risk. The general recommendations for patients with hereditary AT deficiency and pregnant women are mentioned. As the risk of thromboembolic disease is escalated in pregnancy, the LMWH should always be considered. There has been frequently observed that patients with AT deficiency do not elevate anti-Xa-levels when standard prophylactic LMWH doses are used. This fact well illustrates that heparin without AT may not inhibit the active coagulant factors efficiently enough. Therefore, if a high thromboembolic risk in the patient's anamnesis is present, the LMWH dosing should be escalated. In individual cases, concomitant administration of an antithrombin concentrate to the heparin treatment is recommended at the time of delivery or in the case of deep venous thrombosis. In this article, three cases of unusual pregnancy in patients with different types of AT deficiency are reported. The case reports are summarized from the Department of Hematology at Hospital Kolín, the Centre of Hemostasis and Thrombosis at Institute of Hematology and Blood Transfusion in Prague and from cooperating obstetrical departments in the Czech Republic. RESULTS: We demonstrated the threat of hereditary AT deficiency in three case reports. In one case, the estimated risk of thromboembolism ­ type I of AT-deficiency (quantitative) ­ was in a good correlation with real peripartal complications. In the next two cases with different types of AT deficiency, we showed surprising courses of complicated pregnancies. CONCLUSION: As it has been shown, it is not safe to estimate the risk of thromboembolism on the base of causal mutation for AT deficiency. For present clinical practice, we should still remember AT deficiency as a potentially very dangerous thromboembolic disorder for mother and fetus; thus, excellent cooperation of an obstetrician and a hematologist is necessary.

International recommendations on the diagnosis and treatment of acquired hemophilia A.

Acquired hemophilia A (AHA), a rare bleeding disorder caused by neutralizing autoantibodies against coagulation factor VIII (FVIII), occurs in both men and women without a previous history of bleeding. Patients typically present with an isolated prolonged activated partial thromboplastin time due to FVIII deficiency. Neutralizing antibodies (inhibitors) are detected using the Nijmegen-modified Bethesda assay. Approximately 10% of patients do not present with bleeding and, therefore, a prolonged activated partial thromboplastin time should never be ignored prior to invasive procedures. Control of acute bleeding and prevention of injuries that may provoke bleeding are top priorities in patients with AHA. We recommend treatment with bypassing agents, including recombinant activated factor VII, activated prothrombin complex concentrate, or recombinant porcine FVIII in bleeding patients. Autoantibody eradication can be achieved with immunosuppressive therapy, including corticosteroids, cyclophosphamide and rituximab, or combinations thereof. The median time to remission is 5 weeks, with considerable interindividual variation. FVIII activity at presentation, inhibitor titer and autoantibody isotype are prognostic markers for remission and survival. Comparative clinical studies to support treatment recommendations for AHA do not exist; therefore, we provide practical consensus guidance based on recent registry findings and the authors' clinical experience in treating patients with AHA.

Identifying risk factors and optimizing standard of care for patients with acquired haemophilia A: Results from a Czech patient cohort.

INTRODUCTION: Acquired haemophilia A (AHA) is a rare autoimmune disorder, characterized by bleeds of varying severity caused by autoantibodies against factor VIII (FVIII). AIM: Identify risk factors associated with AHA-related deaths/relapses and assess the effect of increased corticosteroid doses. METHODS: AHA patients treated across two specialist centres in the Czech Republic, generally receiving first-line haemostatic therapy with rFVIIa and immunosuppression with corticosteroids/cyclophosphamide, were included. We analysed the association between early death (within 8 weeks of diagnosis [considered disease-related]) and age, malignancy, FVIII levels and bleeding severity. Risk factors associated with reduced 2-year survival and relapse incidence, and the effect of increased corticosteroid doses on early death and remission were also assessed. RESULTS: The demographics of the described cohort (n = 66) were similar to other AHA registries. Early death occurred in 20% of cases. Unlike age and malignancy, FVIII levels <1% and severe bleeding were associated significantly with early death (P = .010 and P = .046, respectively). Patients with underlying malignancy or requiring continued haemostatic therapy exhibited significantly decreased 2-year survival compared with those without these risk factors (P = .007 and P = .006, respectively). Patients with an underlying autoimmune disease relapsed significantly more than those without (P = .015). Higher corticosteroid doses were associated with a significantly increased incidence of early deaths (P < .001), but also with early remission (P < .001). CONCLUSION: Based on this rather large patient cohort, we were able to evaluate the significance of several risk factors associated with treatment outcomes in AHA and the effect of initial treatment with corticosteroids on survival and time to remission.

Range of motion after total knee arthroplasty in hemophilic arthropathy.

BACKGROUND: Outcomes of total knee replacement in cases of hemophilic patients are worse than in patients who undergo operations due to osteoarthritis. Previous publications have reported varying rates of complications in hemophilic patients, such as infection and an unsatisfactory range of motion, which have influenced the survival of prostheses. Our retrospective study evaluated the data of hemophilic patients regarding changes in the development of the range of motion. METHODS: The data and clinical outcomes of 72 total knee replacements in 45 patients with hemophilia types A and B were reviewed retrospectively. Patients were operated between 1998 and 2013. All of the patients were systematically followed up to record the range of motion and other parameters before and after surgery. RESULTS: The mean preoperative flexion contracture was 17° ± 11° (range, 0°-40°), and it was 7° ± 12° (range, 0°-60°) postoperatively. The mean flexion of the knee was 73° ± 30° (range, 5°-135°) before the operation and 80° ± 19° (range, 30°-110°) at the last follow-up. The mean range of motion was 56° ± 34° (range, 0°-130°) before the operation and 73° ± 24° (range, 10°-110°) at the last follow-up. CONCLUSIONS: Statistical analysis suggested that the range of motion could be improved until the 9th postoperative week. The patient should be operated on until the flexion contracture reaches 22° to obtain a contracture < 15° postoperatively or until the contracture reaches 12° to obtain less than 5°. The operation generally does not change the flexion of the knee in cases of hemophilic patients, but it reduces the flexion contracture and therefore improves the range.

Congenital and acquired bleeding disorders.

Hemostasis can be characterized as an array of physiological mechanisms providing both blood fluidity in the intact blood vessels and hemostasis in the event of impaired continuity of the blood vessel wall. The impaired hemo-static balance may lead on the one hand to an increased tendency to bleed, either spontaneously or only in response to an external stimulus. At the opposite end of bleeding are thrombophilic conditions characterized by an increased tendency to blood coagulation and thereby to the development of venous or arterial thrombosis. The hemostatic balance is the result of normal functioning of the blood vessel wall, platelets and plasma agents which include the coagulation and fibrinolytic systems and their inhibitors. By coagulation we understand the process leading to the formation of fibrin networks including the controlled interaction of coagulation factors. It is a physiological process as opposed to thrombosis which can be defined as increased coagulation under pathological conditions. Key words: coagulation - coagulation factors - coagulopathy - hemophilia - inhibitors of coagulation factors deficiencies - purpura - thrombocytopathy - thrombocytopenia.

Predicting the development of hemophilic arthropathy in patients with hemophilia based on patient age: a retrospective single-center database study.

BACKGROUND: Patients with hemophilia (PWH) develop hemophilic arthropathy of the major joints due to recurrent hemarthrosis. This study retrospectively estimated the age at which PWH may expect to develop hemophilic arthropathy and undergo joint replacement surgery. RESEARCH DESIGN AND METHODS: Using retrospective data from PWH at a Czech orthopedic center, Kaplan Meier analyses were used to estimate the cumulative proportions of patients with hemophilic arthropathy and undergoing joint replacement surgery as a function of age. RESULTS: Based on 1028 joint examinations in 167 PWH, hemophilic arthropathy of the knees, elbows, ankles and hips was estimated to develop by a median age of 48, 51, 52 and 61 years, respectively, with ≈80% of patients having such damage by ≈70 years of age. Hemophilic arthropathy of the shoulder occurred much later (median >80 years). In patients undergoing knee or hip replacement surgery, hemophilic arthropathy of the knee and hip occurred at a median age of ≈50 and ≈60 years, respectively, with replacement surgery occurring at a median of ≈70 and >75 years. CONCLUSIONS: In PWH, the risk of developing hemophilic arthropathy accumulates continuously over the patient's lifetime, allowing predictions about the ages at which such damage and joint replacement surgery may occur.

Two novel fibrinogen variants in the C-terminus of the Bß-chain: fibrinogen Rokycany and fibrinogen Znojmo.

Hereditary dysfibrinogenemia is a rare disorder wherein an inherited abnormality in fibrinogen structure may result in defective fibrin function and/or structure. Congenital hypofibrinogenemia is a rare autosomal bleeding disorder, either recessive or dominant, characterized by a low fibrinogen plasma level. A 28-year-old asymptomatic woman (fibrinogen Rokycany) and a 54-year-old man with thrombosis and pulmonary embolism (fibrinogen Znojmo) were investigated for a suspected fibrinogen mutation after abnormal coagulation tests results were obtained. DNA sequencing showed the heterozygous point mutation Bß Asn351Lys in fibrinogen Rokycany and the heterozygous point mutation Bß Arg237Ser in fibrinogen Znojmo, respectively. The kinetics of fibrinopeptide release was found to be normal in both cases. Fibrinolysis was impaired in the Znojmo variant. The average fibril diameters of Znojmo fibrin was slightly increased, but not differing significantly from normal; formed by less fibrils with abrupt fibril terminations. Rheological studies revealed a softer clot. Rokycany fibrin was formed by significantly narrower fibrils than normal fibrin; and the clot was denser than the control clot. Rheological studies revealed a stiffer clot. Impaired fibrinolysis and abnormal clot morphology may be the cause of thrombotic episodes in the patient with Znojmo mutation. New cases of hypofibrinogenemia and dysfibrinogenemia, found by routine coagulation testing, were genetically identified as a novel fibrinogen variants Bß Asn351Lys (fibrinogen Rokycany) and Bß Arg237Ser (fibrinogen Znojmo), respectively.

Two cases of congenital dysfibrinogenemia associated with thrombosis - Fibrinogen Praha III and Fibrinogen Plzen.

Congenital dysfibrinogenemia is a rare disease characterised by inherited abnormality in the fibrinogen molecule, resulting in functional defects. Two patients, a 26-year-old woman and a 61-year-old man, both with history of thrombotic events, had abnormal coagulation test results. DNA sequencing showed the heterozygous gamma Y363N mutation (Fibrinogen Praha III) and the heterozygous Aalpha N106D mutation (Fibrinogen Plzen), respectively. Fibrin polymerisation, after addition of either thrombin or reptilase, showed remarkably delayed polymerisation in both cases. Fibrinolysis experiments showed slower tPA initiated lysis of clots. SDS-PAGE did not show any difference between normal and Praha III and Plzen fibrinogens. Both mutations had a significant effect on platelet aggregation. In the presence of either ADP or TRAP, both mutations caused the decrease of platelet aggregation. SEM revealed abnormal clot morphology, with a large number of free ends and narrower fibres of both fibrin Praha III and Plzen. Praha III mutation was situated in the polymerisation pocket "a". The replacement of the bulky aromatic side chain of tyrosine by the polar uncharged small side chain of asparagine may lead to a conformational change, possibly altering the conformation of the polymerisation pocket. The Plzen mutation is situated in the coiled-coil connector and this replacement of polar uncharged asparagine residue by polar acidic aspartate changes the alpha-helical conformation of the coiled-coil connector; and may destabilise hydrogen bonds in its neighborhood. Although both mutations are situated in different regions of the molecule, both mutations have a very similar effect on fibrinogen functions and both are connected with thromboses.

Patients with acute coronary syndromes have low tissue factor activity and microparticle count, but normal concentration of tissue factor antigen in platelet free plasma: a pilot study.

OBJECTIVES: Tissue factor (TF) is a main initiator of coagulation cascade. Its determination in conditions of acute coronary syndrome is logistically difficult. Hence, in our study, the activity and the concentration of TF and the count of microparticles in the platelet free plasma (PFP) were determined. METHODS: Blood was drawn from both coronary sinus and femoral vein circulation in a cohort of 40 patients. TF activity was measured by activation of factor X in the presence of factor VIIa, whereas microparticles were detected using flow cytometry. TF antigen concentrations were determined using the ELISA test. RESULTS: TF activity in the stable angina subgroup was not significantly different from the control group (18.12 +/- 3.35 mOD/min vs. 17.72 +/- 4.05 mOD/min, respectively), but it was significantly lower in the unstable angina (7.62 +/- 4.19 mOD/min) and myocardial infarction (MI) (3.56 +/- 3.85 mOD/min) subgroups (P < 0.05). Results from the coronary sinus and femoral vein circulations were not significantly different. The count of microparticles decreased according to the severity of the acute coronary syndrome: control group, 520 +/- 172; stable angina subgroup, 532 +/- 167; unstable angina subgroup, 392 +/- 142; and MI subgroup, 165 +/- 30 (P < 0.05). There were no significant differences in concentrations of TF antigen in four subgroups. CONCLUSIONS: These results suggest that the procoagulant TF-bearing microparticles could be recruited from PFP by interaction with platelets and blood cells in the conditions of acute coronary syndrome.

CEBPA polymorphisms and mutations in patients with acute myeloid leukemia, myelodysplastic syndrome, multiple myeloma and non-Hodgkin's lymphoma.

The transcription factor CCAAT/enhancer binding protein (C/EBP)alpha is a myeloid-specific transcription factor which is required for normal myeloid differentiation. C/EBPalpha is encoded by an intronless gene that is 2783 bp long and maps to human chromosome 19q13.1. C/EBPalpha is a member of the basic region leucine zipper (bZIP) class of DNA-binding proteins. The loss of function of C/EBPalpha has leukemogenic potential. Four types of polymorphisms and 25 mutations (3 already known mutations and 22 novel mutations) were detected in CEBPA (gene for the transcription factor CCAAT/enhancer binding protein (C/EBP) alpha) in analysed samples from 390 patients with myelodysplastic syndrome (MDS) and hematologic malignancies. CEBPA mutations were found in 14/152 (9.2%) of acute myeloid leukemia (AML) patients' samples, 6/143 (4.2%) of MDS patients' samples, 2/56 (3.6%) of non-Hodgkin's lymphoma (NHL) patients' samples and 2/39 (5.1%) of multiple myeloma (MM) patients' samples. No C/EBPalpha mutations were detected in healthy donors (41 individuals). We discuss how these mutations can affect the cellular function of C/EBPalpha and block the myeloid differentiation.

A novel fibrinogen variant--Liberec: dysfibrinogenaemia associated with gamma Tyr262Cys substitution.

OBJECTIVE: A 22-yr-old woman had abnormal preoperative coagulation test results and congenital dysfibrinogenaemia was suspected. PATIENTS AND METHODS: The patient from Liberec (Czech Republic) had a low fibrinogen plasma level as determined by Clauss method, normal fibrinogen level as determined by immunoturbidimetrical method, and prolonged thrombin time. To identify the genetic mutation responsible for this dysfibrinogen, genomic DNA extracted from the blood was analysed. Fibrin polymerisation measurement, kinetics of fibrinopeptide release, fibrinogen clottability measurement and scanning electron microscopy were performed. RESULTS: DNA sequencing showed the heterozygous fibrinogen gamma Y262C mutation. Kinetics of fibrinopeptide release was normal, however fibrin polymerisation was impaired. Fibrinogen clottability measurement showed that only about 45% molecules of fibrinogen are involved in the clot formation. Scanning electron microscopy revealed thicker fibres, which were significantly different from the normal control. CONCLUSION: A case of dysfibrinogenaemia, found by routine coagulation testing, was genetically identified as a novel fibrinogen variant (gamma Y262C) that has been named Liberec.

Acquired dysfibrinogenemia secondary to multiple myeloma.

Abnormal coagulation properties indicative of a dysfibrinogen were found in the plasma of a 72-year-old male with multiple myeloma (IgGkappa, stage IIIA). The patient had high paraprotein concentration (85.75 g/l) and prolonged thrombin time (76.8 s), activated partial thromboplastin time (39.5 s), prothrombin time (23.5 s) and reptilase time (72.0 s). The fibrinogen level was increased. The fibrin polymerization induced by both thrombin and reptilase was impaired. Scanning electron microscopy revealed abnormal clot morphology. After six months of treatment, the paraprotein level decreased (19.48 g/l) and coagulation normalized as well as fibrin polymerization and fibrin clot morphology. It was found that the paraprotein interacts with the gamma-chain of fibrinogen. Acquired dysfibrinogenemia associated with multiple myeloma was diagnosed in the 72-year-old patient.

High-resolution melting analysis for detection of MYH9 mutations.

May-Hegglin anomaly (MHA), Sebastian (SBS), Fechtner (FTNS) and Epstein (EPS) syndromes are rare autosomal dominant disorders with giant platelets and thrombocytopenia. Other manifestations of these disorders are combinations of the presence of granulocyte inclusions and deafness, cataracts and renal failure. Currently, MHA, SBS, FTNS and EPS are considered to be distinct clinical manifestation of a single illness caused by mutations of the MYH9 gene encoding the heavy chain of non-muscle myosin IIA (NMMHC-IIA). As the MYH9 gene has a high number of exons, it takes much time and material to use this method for the detection of MYH9 mutations. Recently, a new method has been introduced for scanning DNA mutations without the need for direct sequencing: high-resolution melting analysis (HRMA). Mutation detection with HRMA relies on the intercalation of the specific dye (LC Green plus) in double-strand DNA and fluorescence monitoring of PCR product melting profiles. In our study, we optimized the conditions and used HRMA for rapid screening of mutations in all MYH9 exons in seven affected individuals from four unrelated families with suspected MYH9 disorders. Samples identified by HRMA as positive for the mutation were analysed by direct sequencing. HRMA saved us over 85% of redundant sequencing.

Fibrinogen Nový Jicín and Praha II: cases of hereditary Aalpha 16 Arg-->Cys and Aalpha 16 Arg-->His dysfibrinogenemia.

INTRODUCTION: Various dysfibrinogenemias have been described worldwide. This paper describes two new cases of dysfibrinogenemia identified in the Czech Republic. MATERIALS AND METHODS: The proposita of fibrinogen Nový Jicín, a 12-year-old girl, presented with hemorrhagic complications, low Clauss fibrinogen level (0.3 g/l) and prolonged both thrombin (70.8 s) and reptilase (>180 s) time. Her mother and sister both presented with normal coagulation tests, normal fibrinogen level and reported no history of bleeding. The carriers of the fibrinogen Praha II were a 31-year-old man and his 11-year-old daughter. They both presented with low fibrinogen Clauss level (0.88 g/l) and prolonged thrombin and reptilase time. To identify the genetic mutation responsible for these dysfibrinogens, genomic DNA extracted from the blood was analyzed. The presence of the mutant chains in the circulation was determined by MALDI-TOF mass spectroscopy. Scanning electron micrographs of the patients' fibrin clots were obtained. RESULTS: The kinetics of fibrinopeptide release and fibrin polymerization were impaired for both fibrinogen Nový Jicín and Praha II. DNA sequencing showed heterogeneous fibrinogen Aalpha R16C mutation in the fibrinogen Nový Jicín case and heterogeneous fibrinogen Aalpha R16H in the fibrinogen Praha II case. The mutant chains were found to be expressed to the circulation by MALDI-TOF mass spectroscopy. Scanning electron micrographs of the patient's fibrin clot were found to be abnormal. CONCLUSIONS: The case of dysfibrinogenemia Aalpha R16C-fibrinogen Nový Jicín and the case of dysfibrinogenemia Aalpha R16H were found by routine coagulation testing and were genetically identified.

Rationale for individualizing haemophilia care.

Owing to the heterogeneity in the clinical phenotype of haemophilia A and B, it is now recognized that disease severity (based on factor VIII/IX activity) may no longer be the most appropriate guide for treatment and that a 'one-size-fits-all' approach is unlikely to achieve optimal therapy. Based on the present literature and consensus views of a group of experts in the field, this article highlights key gaps in the understanding of the diverse relationships between bleeding phenotype and factors such as joint health, genetic susceptibility, laboratory parameters, quality of life and management of pain. Early prophylaxis is a potential 'gold standard' therapy and issues surrounding inhibitor development, variations in its clinical use and long-term outcomes are discussed. Comprehensive treatment should be individualized for all patients (including those with mild or moderate haemophilia and carriers). Wherever possible all patients should be given prophylaxis. However, adult patients with a milder haemophilia phenotype may be candidates for ceasing prophylaxis and switching to on-demand treatment. Regardless, all treatment (on-demand and prophylaxis) should be tailored towards both the patient's personal needs and their clinical profile. In addition, as the associations between risk factors (psychosocial, condition-related and treatment-related) and clinical features are unique to each patient, an individualized approach is required to enable patients to alter their behaviour in response to them. The practical methodologies needed to reach this goal of individualized haemophilia care, and the health economic implications of this strategy, are ongoing topics for discussion.

Does asymptomatic carriage of FV Leiden and FII prothrombin mutations in heterozygous configuration pose an increased risk of thrombembolic complications in the course of pregnancy, labor and puerperium?

OBJECTIVE: To evaluate the course of pregnancy and puerperium in asymptomatic carriers of FV Leiden and FII prothrombin mutation in heterozygous configuration in terms of risk of thrombembolic disease (TED) and late pregnancy complications. To evaluate whether global prophylactic LMWH administration during pregnancy benefits these women. METHODS: We monitored the incidence of thrombembolic events and severe late pregnancy complications in 473 asymptomatic carriers of FV Leiden and FII prothrombin mutation in heterozygous configuration. In 253 women, preventive LMWH application was introduced already during pregnancy. In 220 women, the application of LMWH was commenced as late as on the delivery day. In both groups application of LMWH continued during the puerperium. RESULTS: The incidence of TED in the whole group of carriers of thrombophylic mutations accounted for 0.19%. The incidence of severe late pregnancy complications was low - 2.5% compared with general population of pregnant women (6.4%). CONCLUSIONS: No direct causal relationship was established between asymptomatic carriage of Leiden and prothrombin mutation in heterozygous configuration and the occurrence of severe late pregnancy complications. There was no benefit from general LMWH prophylaxis started as early as pregnancy in these women and thus we consider it unnecessary.

Economic evaluation of rFVIIa high initial dose compared to rFVIIa standard initial dose in patients with haemophilia with inhibitors using the Czech HemoRec registry.

INTRODUCTION: In the treatment of bleeds in haemophilia patients with inhibitors, a high initial dose of recombinant Factor VIIa (rFVIIa) provides at least equal efficacy and a similar safety profile to a standard initial dose. However, no pharmacoeconomic comparison between these dosing regimens has previously been performed. Here, we assess the pharmacoeconomics of high (>120 µg/kg) versus standard (≤120 µg/kg) initial rFVIIa dose in inhibitor patients and the impact of time to treatment initiation on costs and outcomes. METHODS: In a retrospective analysis, observational data on bleed characteristics, rFVIIa treatment, hospitalizations and outcomes were extracted from the Czech Republic HemoRec registry. Crude comparisons and generalized linear regression modelling (GLM; correcting for patient differences) were performed to compare costs and outcomes between the high and standard initial dosing groups. RESULTS: Of 314 rFVIIa-treated bleeding episodes (12 inhibitor patients), most were spontaneous joint bleeds and 67.5% were treated with a high initial dose. In the crude comparison, high initial rFVIIa dosing was associated with a lower mean number of doses needed to achieve haemostasis compared with standard dosing (p<0.001), but higher total dose and costs (p ≤ 0.008). However, regression analyses revealed that high initial dose was associated with similar costs (p=0.891) and a shorter time to bleeding resolution (p=0.014). Increasing time to treatment initiation increased both time to bleeding resolution and total costs. CONCLUSION: Compared with a standard dose, a high initial rFVIIa dose may improve treatment outcomes without increasing costs. Early treatment initiation may reduce treatment costs.

Two novel mutations in the fibrinogen γ nodule.

INTRODUCTION: Congenital dysfibrinogenemia and hypofibrinogenemia are rare diseases characterized by inherited abnormality in the fibrinogen molecule, resulting in functional defects (dysfibrinogenemia) or low fibrinogen plasma levels (hypofibrinogenemia). MATERIALS AND METHODS: We have described two abnormal fibrinogens - fibrinogen Hranice (γ Phe204Val) and Praha IV (γ Ser313Gly). The carrier of the Hranice mutation was a 40-year-old female with low fibrinogen levels. The carrier of the Praha IV mutation was a 42-year-old man with a history of idiopathic thrombosis, low functional fibrinogen levels, and a prolonged thrombin time. RESULTS: Fibrin polymerization kinetics measurement was normal in both cases (after the addition of either thrombin or reptilase), as well as was fibrinolysis. Scanning electron microscopy and confocal microscopy revealed significantly wider fibers in both cases, when compared with fibers prepared from healthy control samples. Although both cases are situated in the γ-nodule, they manifested differently. While the γ Ser313Gly mutation manifested as dysfibrinogenemia with a thrombotic background, the γ Phe204Val mutation manifested as hypofibrinogenemia without clinical symptoms. The mutation sites of both fibrinogens are in highly conserved regions of the fibrinogen γ chains. γ Ser313 is situated in a class 16:18 ß hairpin and is involved in hydrogen bonding with γ Asp320. γ Phe204 is situated in an inverse γ turn and may be involved in π-π interactions. CONCLUSIONS: Both mutations cause conformational changes in fibrinogen, which lead either to impaired fibrinogen assembly (fibrinogen Hranice) or abnormal fibrinogen function (fibrinogen Praha IV).