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Background and Objectives: Quantifying the contribution of individual coagulation factors to haemostasis may aid our understanding of the haemostatic function in patients with rare coagulation deficiencies (RCDs) and the exploration of suitable treatments., Materials and Methods: Reconstituted blood prepared from specific coagulation factor-deficient plasma (factor [F]II; prothrombin, FV, FVII, FVIII, FIX, FX, FXI or FXII) and red blood cell/platelet products were used to simulate the whole blood of patients with RCD. We prepared in vitro treatment models for patients with prothrombin deficiency using coagulation factor agents and fresh frozen plasma. Haemostatic function was measured using a microchip flow chamber system at 600 s -1 ., Results: The haemostatic function was low, especially in blood samples reconstituted with prothrombin- and FX-deficient plasma. In a plasma transfusion model of prothrombin deficiency, haemostatic function recovered after 10% replacement with normal plasma and reached a plateau at ≧60% replacement. A treatment model of prothrombin deficiency with prothrombin complex concentrates revealed dose-dependent therapeutic effects in the range of 0-50 IU/kg., Conclusion: Microchip flow chamber system-based quantification of haemostatic function using reconstituted blood could predict haemostasis and therapeutic effects of treatments in patients with prothrombin deficiency., (© 2024 International Society of Blood Transfusion.)

Introduction: Thrombin generation assays (TGAs) assess the overall functionality of the hemostatic system and thereby provide a reflection of the hemostatic capacity of patients with disorders in this system. Currently, four (semi-)automated TGA platforms are available: the Calibrated Automated Thrombogram, Nijmegen Hemostasis Assay, ST Genesia and Ceveron s100. In this study, we compared their performance for detecting patients with congenital single coagulation factor deficiencies., Materials and Methods: Pooled patient samples, healthy control samples and normal pooled plasma were tested on all four platforms, using the available reagents that vary in tissue factor and phospholipid concentrations. The TGA parameters selected for analysis were peak height and thrombin potential. Results were normalized by using the calculated mean of healthy controls and a correction for between-run variation. Outcomes were presented as relative values, with the mean of healthy controls standardized to 100 %., Results: Across all platforms and reagents used, thrombin potentials and peak heights of samples with coagulation factor deficiencies were lower than those of healthy controls. Reagents designed for bleeding tendencies yielded the lowest values on all platforms (relative median peak height 19-32 %, relative median thrombin potential 19-45 %). Samples representing more severe coagulation factor deficiencies generally exhibited lower relative peak heights and thrombin potentials., Conclusions: Thrombin generation assays prove effective in differentiating single coagulation factor deficient samples from healthy controls, with modest discrepancies observed between the platforms. Reagents designed for assessing bleeding tendencies, featuring the lowest tissue factor and phospholipid concentrations, emerged as the most suitable option for detecting coagulation factor deficiencies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: There are significant differences in the activated partial thromboplastin time (APTT) critical values reported in different studies, most of which does not make recommendations for any specific clear detection systems. The International Council for Standardization in Hematology (ICSH) recommends that APTT critical values be established based on the reagent type, coagulation factor sensitivity and heparin response. The objective of this study was to establish APTT critical values by using different reagents and based on single coagulation factor deficiencies., Methods: The APTT values were determined in commercial endogenous coagulation factor-deficient plasma at concentrations of 1 IU/dL, 2 IU/dL, 5 IU/dL, 10 IU/dL, 20 IU/dL, and 30 IU/dL by using four assay systems. The retrospective collection of data from patients who lacked factor VIII (FVIII), FIX, or FXI alone was performed. Receiver operating characteristic (ROC) curves were constructed to assess the diagnostic accuracy of APTT for identifying patients with an endogenous coagulation factor activity < 5 IU/dL., Results: The APTT values in the plasma samples with the same concentrations of endogenous coagulation factors were significantly different among the four assay systems (P < 0.001). The suggested critical values of APTT were 40.0 s for Sysmex CS5100 (Actin FSL), 58.0 s for Sysmex CS5100 (Actin), 51.8 s for STA-R Evolution (STA-PTTA), and 64.8 s for ACL TOP 700 (HemosIL SynthasIL). On the basis of the ROC curve, the optimal threshold values for APTT (STA-PTTA) were 55.8 s in patients with a simple deficiency of FVIII (sensitivity = 100%, specificity = 85.7%, area under the ROC curve (AUC) = 0.982), 54.3 s in patients with a simple deficiency of FIX (sensitivity = 100%, specificity = 92.9%, AUC = 0.986), and 71.7 s in patients with a simple deficiency of FXI (sensitivity = 100%, specificity = 94.1%, AUC = 0.992), which were closer (difference of 0.6-2.5 s) to the cutoff points for commercial plasma at equal factor levels., Conclusions: APTT critical values need to be established for different reagents based on the presence of a single coagulation factor deficiency., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Coagulopathies are well documented after acute radiation exposure at hematopoietic doses, and radiation-induced bleeding is notably one of the two main causes of mortality in the hematopoietic acute radiation syndrome. Despite this, understanding of the mechanisms by which radiation alters hemostasis and induces bleeding is still lacking. Here, male Göttingen minipigs received hematopoietic doses of 60Co gamma irradiation (total body) and coagulopathies were characterized by assessing bleeding, blood cytopenia, fibrin deposition, changes in hemostatic properties, coagulant/anticoagulant enzyme levels, and markers of inflammation, endothelial dysfunction, and barrier integrity to understand if a relationship exists between bleeding, hemostatic defects, bone marrow aplasia, inflammation, endothelial dysfunction and loss of barrier integrity. Acute radiation exposure induced coagulopathies in the Göttingen minipig model of hematopoietic acute radiation syndrome; instances of bleeding were not dependent upon thrombocytopenia. Neutropenia, alterations in hemostatic parameters and damage to the glycocalyx occurred in all animals irrespective of occurrence of bleeding. Radiation-induced bleeding was concurrent with simultaneous thrombocytopenia, anemia, neutropenia, inflammation, increased heart rate, decreased nitric oxide bioavailability and endothelial dysfunction; bleeding was not observed with the sole occurrence of a single aforementioned parameter in the absence of the others. Alteration of barrier function or clotting proteins was not observed in all cases of bleeding. Additionally, fibrin deposition was observed in the heart and lungs of decedent animals but no evidence of DIC was noted, suggesting a unique pathophysiology of radiation-induced coagulopathies. These findings suggest radiation-induced coagulopathies are the result of simultaneous damage to several key organs and biological functions, including the immune system, the inflammatory response, the bone marrow and the cardiovasculature., (©2021 by Radiation Research Society. All rights of reproduction in any form reserved.)

Rattlesnakes are a diverse clade of pit vipers (snake family Viperidae, subfamily Crotalinae) that consists of numerous medically significant species. We used validated in vitro assays measuring venom-induced clotting time and strength of any clots formed in human plasma and fibrinogen to assess the coagulotoxic activity of the four medically relevant Mexican rattlesnake species Crotalus culminatus, C. mictlantecuhtli, C. molossus , and C. tzabcan . We report the first evidence of true procoagulant activity by Neotropical rattlesnake venom in Crotalus culminatus . This species presented a strong ontogenetic coagulotoxicity dichotomy: neonates were strongly procoagulant via Factor X activation, whereas adults were pseudo-procoagulant in that they converted fibrinogen into weak, unstable fibrin clots that rapidly broke down, thereby likely contributing to net anticoagulation through fibrinogen depletion. The other species did not activate clotting factors or display an ontogenetic dichotomy, but depleted fibrinogen levels by cleaving fibrinogen either in a destructive (non-clotting) manner or via a pseudo-procoagulant mechanism. We also assessed the neutralization of these venoms by available antivenom and enzyme-inhibitors to provide knowledge for the design of evidence-based treatment strategies for envenomated patients. One of the most frequently used Mexican antivenoms (Bioclon Antivipmyn®) failed to neutralize the potent procoagulant toxic action of neonate C. culminatus venom, highlighting limitations in snakebite treatment for this species. However, the metalloprotease inhibitor Prinomastat substantially thwarted the procoagulant venom activity, while 2,3-dimercapto-1-propanesulfonic acid (DMPS) was much less effective. These results confirm that venom-induced Factor X activation (a procoagulant action) is driven by metalloproteases, while also suggesting Prinomastat as a more promising potential adjunct treatment than DMPS for this species (with the caveat that in vivo studies are necessary to confirm this potential clinical use). Conversely, the serine protease inhibitor 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) inhibited the direct fibrinogen cleaving actions of C. mictlantecuhtli venom, thereby revealing that the pseudo-procoagulant action is driven by kallikrein-type serine proteases. Thus, this differential ontogenetic variation in coagulotoxicity patterns poses intriguing questions. Our results underscore the need for further research into Mexican rattlesnake venom activity, and also highlights potential limitations of current antivenom treatments., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Seneci, Zdenek, Chowdhury, Rodrigues, Neri-Castro, Bénard-Valle, Alagón and Fry.)

Background: Congenital disorders of glycosylation are rare inherited diseases affecting many different proteins. The lack of glycosylation notably affects the hemostatic system and leads to deficiencies of both procoagulant and anticoagulant factors., Objective: To assess the hemostatic balance in patients with multiple coagulation disorders by using a thrombin generation assay., Method: We performed conventional coagulation assays and a thrombin generation assay on samples from patients with congenital disorder of glycosylation. The thrombin generation assay was performed before and after activation of the protein C system by the addition of soluble thrombomodulin., Results: A total of 35 patients were included: 71% and 57% had low antithrombin and factor XI levels, respectively. Protein C and protein S levels were abnormally low in 29% and 26% of the patients, respectively, whereas only 11% displayed low factor IX levels. Under baseline conditions, the thrombin generation assay revealed a significantly higher endogenous thrombin potential and thrombin peak in patients, relative to controls. After spiking with thrombomodulin, we observed impaired involvement of the protein C system. Hence, 54% of patients displayed a hypercoagulant phenotype in vitro. All the patients with a history of stroke-like episodes or thrombosis displayed this hypercoagulant phenotype., Conclusion: A thrombin generation assay revealed a hypercoagulant in vitro phenotype under baseline condition; this was accentuated by impaired involvement of the protein C system. This procoagulant phenotype may thus reflect the risk of severe vascular complications. Further research will have to determine whether the thrombin generation assay is predictive of vascular events., (© 2019 French National Institute of Health and Medical Research. © 2019 International Society on Thrombosis and Haemostasis.)

Background: Conventional coagulation assays (CCAs), prothrombin time (PT)/international normalized ratio (INR) and activated partial thromboplastin time (aPTT), detect clotting factor (CF) deficiencies in hematologic disorders. However, there is controversy about how these CCAs should be used to diagnose, treat, and monitor trauma-induced coagulopathy. Study objectives were to determine whether CCA abnormalities are reflective of deficiencies of coagulation factor activity in the setting of severe injury., Methods: Patients without previous CF deficiency within a prospective database at an ACS-verified Level I trauma center had CF activity levels, PT/INR, aPTT, and fibrinogen levels measured upon emergency department arrival from 2014 to 2017. Linear regression assessed how CF activity explained the aPTT and PT/INR variation. Prolonged CCA values were set as INR greater than 1.3 and aPTT greater than 34 seconds. CF deficiency was defined as less than 30% activity, except for fibrinogen, defined as less than 150 mg/dL., Results: Sixty patients with a mean age of 35.8 (SD, 13.6) years and median New Injury Severity Score of 32 (interquartile range, 12-43) were included; 53.3% sustained blunt injuries, 23.3% required massive transfusion, and mortality was 11.67%. Overall, 44.6% of the PT/INR variance and 49.5% of the aPTT variance remained unexplained by CF activity. Deficiencies of CFs were: common pathway, 25%; extrinsic pathway, 1.7%; and intrinsic pathway, 6.7%. The positive predictive value for CF deficiencies were: (1) PT/INR greater than 1.3:4.4% for extrinsic pathway, 56.5% for the common pathway; (2) aPTT greater than 34 seconds:16.7% for the intrinsic pathway, 73.7% for the common pathway., Conclusion: Almost half of the variances of PT/INR and aPTT were unexplained by CF activity. Prolonged PT/INR and aPTT were poor predictors of deficiencies in the intrinsic or extrinsic pathways; however, they were indicators of common pathway deficiencies., Level of Evidence: Prognostic, level III.

Background: Four-factor prothrombin complex concentrate (4F-PCC) is US Food and Drug Administration approved for the urgent reversal of coagulation factor deficiency induced by a vitamin K antagonist complicated by acute major bleeding or in situations in which invasive procedures are urgently needed. Although recent evidence suggests the superiority of 4F-PCC over plasma for on-label indications, the off-label use of 4F-PCC has not been rigorously studied., Study Design and Methods: Eighty-nine patients receiving 4F-PCC at a single institution from July 2016 to December 2017 were retrospectively analyzed. Two cohorts, "On-Label" and "Off-Label" uses of 4F-PCC, were evaluated, comparing patient characteristics, blood utilization, and clinical outcomes including in-hospital mortality., Results: Patients receiving 4F-PCC for off-label reasons (n = 46) were younger and sicker compared to those receiving 4F-PCC for on-label reasons (n = 43). Notably, the mortality rate for off-label use was approximately twofold greater than the mortality rate for on-label use (26 of 46 [56.5%] vs. 12 of 43 [27.9%]; p = 0.006). Patients receiving 4F-PCC for off-label reasons received more units per patient of each blood component than their on-label counterparts. The average cost estimate per patient for 4F-PCC was similar (approx. $4300) in each cohort., Conclusion: 4F-PCC is an effective but expensive treatment option for those requiring urgent reversal of vitamin K antagonist-induced coagulopathy. However, providers should be conscious of the high costs and questionable efficacy when using 4F-PCC off-label., (© 2019 AABB.)

Objective: To explore the change of coagulation function and associated potential mechanisms and the relationship between coagulation disorders and deep venous thrombosis (DVT) after subarachnoid hemorrhage (SAH) within 3 days of onset., Methods: A total of 150 patients with SAH within 3 days of onset and 100 healthy individuals were recruited. Thrombelastography analysis and traditional laboratory tests were performed. Tissue factor (TF), tissue factor pathway inhibitor (TFPI) and activated protein C (APC) were tested by using enzyme-linked immunoassay kits. Extremities of patients with SAH were scanned by Doppler ultrasonography. Subgroup analysis was performed in patients with SAH based on the presence or lack of DVT., Results: Compared with control groups, R (an indicator of coagulation factor function in thrombelastography) was significantly decreased (4.32 ± 0.99 minutes vs. 6.00 ± 0.75 minutes; P < 0.001), especially in patients with DVT. TF was significantly increased (20.84 ± 4.15 pg/mL vs. 5.24 ± 1.86 pg/mL; P < 0.001). TFPI was decreased (50.42 ± 5.81 ng/mL vs. 64.10 ± 6.04 ng/mL). APC had no apparent changes. R was negatively correlated with TF (r = 0.358; P < 0.05) and positively correlated with TFPI (r = 0.325; P < 0.05) and APC (r = 0.162; P < 0.05). TF, TFPI, and APC had the same variation characteristics in the DVT subgroup compared with the no DVT subgroup. DVT was associated with R through association analysis (r = 0.369; P < 0.05). The R cutoff value for estimating the presence of DVT was 3.65 minutes., Conclusions: Coagulation factor hyperfunction may be mainly accompanied within 3 days of SAH onset and may induce DVT. This situation may be associated with TF-TFPI-APC imbalance. R = 3.65 minutes was a potential intervention point to prevent the risk of DVT in this population., (Copyright © 2017. Published by Elsevier Inc.)

Rare diseases are defined as life-threatening or chronically debilitating diseases with a prevalence of less than one per 2000 according to the European Union or one per 1250 according to the USA. Congenital rare bleeding disorders RBD are reported in most populations, with incidence varying from 1 in 5000 (Hemophilia A), 1:30,000 (Hemophilia B) to much rarer (1:500,000 for FVII deficiency, 1-3 million for Prothrombin or FXIII deficiency). Acquired Hemophilia A is also a rare bleeding disorder with estimated frequency of 1 in million. Most RBDs are inherited as autosomal recessive (AR); however, heterozygous carriers with varying degrees of corresponding factor deficiency may render an unpredictable propensity for bleeding. In patients with bleeding symptoms, laboratory assessment and especially molecular techniques currently enable accurate diagnosis and may provide tools for prenatal and family counseling. Currently hemostasis control is mainly based upon replacement of the missing coagulation factors (unless presence of inhibitors renders it impossible), however future gene therapy and disruptive, non-replacement alternatives may be promising for patients with RBD., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Recently several variants of clotting factors have shown a peculiar behavior so that they appear as new defects. The factors involved are FII, FV and FIX. Prothrombin deficiency is usually associated with bleeding. Recently a few prothrombin abnormalities involving Arg396 mutations, have been demonstrated to show antithrombin resistance with the consequent appearance of a thrombophilic state and venous thromboses in young age. The same is true for an abnormal FIX (FIX Padua). The thrombotic manifestations in the latter condition are also venous. The abnormal FIX (FIX Padua) is characterized by a great increase in FIX activity whereas FIX antigen is only slightly increased. The condition is due to an Arg338Lys mutation. The increased intrinsic clotting activity of this abnormal FIX is being investigated as a useful therapeutic approach in homophile B patients. Another new clotting disorder is represented by two abnormal FV (FV East Texas and FV Amsterdam). These are characterized by a deletion of part of the B domain of FV resulting in a "short" FV. The condition is characterized by a mild bleeding tendency due to high levels of Tissue Factor pathway inhibitor. The "short" factor V is in fact resistant to the action of Tissue Factor pathway inhibitor which is sharply increased in these patients. These new clotting entities have again demonstrated that the study of patients who show a tendency to venous thrombosis or a mild bleeding condition that cannot be explained on the basis of our current concepts of blood coagulation, may represent "new" coagulation disorders. All persons interested in thrombotic or hemorrhagic disorders should be informed about these new clinical and laboratory conditions.

Mixing tests in coagulation studies allow the laboratory to correctly differentiate factor deficiency from inhibitors as the cause of a prolonged clotting time. This is important in terms of subsequent laboratory follow-up and clinical patient management. In this chapter, a suggested method of performing mixing tests is given, with procedures applying two different formulas for interpretation, the percent correction and the index of circulating anticoagulant.

The activated partial thromboplastin time (APTT) is a useful global assay for the assessment of the contact factor pathway of hemostasis and its inhibitors. The test is usually performed on fully automated analyzers using commercially prepared reagents. The three main clinical areas of interest are detection of factor deficiencies, detection of lupus anticoagulants and in the monitoring of therapy with unfractionated heparin. Methods are described here for assessing APTT reagents for their sensitivity to clotting time prolongation in each of these areas of interest.

Pulmonary embolism is a complication of deep vein thrombosis. It occurs in the population with a normal clotting mechanism, but it may also occur in patients with congenital bleeding conditions. Here, we report on all cases of pulmonary embolism in congenital hemorrhagic disorders. All reported cases of pulmonary embolism in congenital coagulation disorders have been gathered by a time-unlimited PubMed search. Cross-checking of the references listed at the end of the single papers was carried out to avoid omissions. Seventy-two patients had an objectively demonstrated pulmonary embolism. The event occurred in patients with fibrinogen, factor V, factor VIII (FVII), FVIII, FIX, and FXI deficiency, and in those with von Willebrand's disease. No embolism was reported in FII, factor X, and FXIII deficiency. Thirty were women and 28 were men, whereas in the remaining 14 cases, sex was not reported. Age varied from 6 to 81 years (mean age 34.3 years). The management varied from only supportive to the administration of unfractionated heparin, low-molecular-weight heparin, and anti-vitamin K medications, accompanied by adequate replacement therapy. Evolution was fair or good in the majority of cases, but there were 10 fatalities. Risk factors were present in 61 patients. The most frequent of these were replacement therapy (35 cases), surgery (34), and old age (13). Some patients had more than one risk factor. Eleven patients had no risk factors. There are discrepancies in the prevalence of pulmonary embolism among different clotting disorders. The conditions most frequently affected are FVII deficiency and fibrinogen defects. The significance of the findings is discussed.

Introduction: Prothrombin time (PT) and activated partial thromboplastin time (APTT) sensitivity for detecting isolated factor deficiencies varies with different reagents and coagulometers. The Clinical and Laboratory Standards Institute (CLSI) H47A2 guideline proposed a method to calculate these sensitivities, but some inconsistency has been reported. This study aimed to calculate factor sensitivities using CLSI guideline and to compare them with those obtained from single factor-deficient patients' data., Methods: Different mixtures of normal pooled and deficient plasmas were prepared (<1IU/dL to 100 IU/dL) according to the CLSI H47A2 guideline. PT with rabbit brain (RB) and human recombinant (HR) thromboplastins, APTT and factors' activities were measured in an ACL TOP coagulometer. Sensitivities (maximum factor concentration that produces PT or APTT values out of the reference range) were calculated from mixtures and from patients with single-factor deficiencies: 17 factor FV, 36 FVII, 19 FX, 39 FVIII, 15 FIX 15 FXI and 24 FXII., Results: PT sensitivity with RB was as follows: FV 38 and 59, FVII 35 and 58, FX 56 and 64 IU/dL; PT sensitivity with HR was as follows: FV 39 and 45, FVII 51 and 50, FX 33 and 61 IU/dL; and APTT sensitivity was as follows: FV 39 and 45, FX 32 and 38, FVIII 47 and 60, FIX 35 and 44, FXI 33 and 43, FXII 37 and 46 IU/dL, respectively., Conclusions: Reagent-coagulometer combination has adequate sensitivities to factor deficiencies according to guideline recommendations (>30 IU/dL). These should not be considered as actual sensitivities because those obtained by analysing patients' plasmas with single-factor deficiencies were higher for most factors and could induce misinterpretation of the basic coagulation test results., (© 2015 John Wiley & Sons Ltd.)

Background: Rare factor deficiencies (RFDs) are autosomal recessively inherited coagulation factor deficiencies encountered at a frequency of between one in 500, 000 and one in two million., Materials and Methods: One hundred and ninety-two patients, diagnosed as having RFD, followed and treated in our clinic between 1990 and 2013 were retrospectively evaluated in this study., Results: From the 192 patients, 142 had FVII, 15 had FX, 14 had FXI, 10 had fibrinogen, six had FV, two had FXIII, two had FV + FVIII and one had FII deficiency. One hundred and thirty of the cases were boys and 62 were girls. The age range was 2 weeks to 24 years and the ages at the admission were between 2 weeks and 16 years. The rate of consanguinity was 49.4%. Eighty-eight of our patients were asymptomatic (45.8%) and 104 were symptomatic (54.2%). Asymptomatic patients were diagnosed by family histories (39.8%), preoperative laboratory studies (54.6%) and operational bleeding (5.6%). Sixty-eight of our symptomatic patients displayed grade II (65.4%) and 36 displayed grade III bleeding symptoms (34.6%). First bleeding regions were skin (33%), nose (28%), central nervous system (CNS) (15.5%), oral cavity (10.5%), soft tissue (6%), joint (3%), urinary system (2%) and gastrointestinal system (GIS) (2%), respectively. The bleeding prevalence rates of our symptomatic patients are listed as epistaxis 62.5%, skin bleedings 53%, oral cavity bleeding 28.8%, haematomas 18.3%, CNS bleedings 17.3%, haemarthrosis 14.4%, GIS bleedings 3.8%, menorrhagia 2.9%, haematuria 1.9%, bleeding because of operations 1.9% and iliopsoas bleedings 1.9%. CNS bleedings (41%) take the first place among the serious bleedings of our cases, followed by haemarthrosis (36.4%), GIS bleedings (18.1%) and iliopsoas bleedings (4.5%). Prophylaxy was applied to nine patients (five patients with FVII, two patients with fibrinogen and one each with FV and FX deficiency)., Conclusions: The characteristics of clinical presentations, first bleeding attacks, bleeding prevalence and severe bleedings as well as prophylactic approaches are discussed in this article.

Based on the premise that the capacity of plasma to generate thrombin in vitro is a comprehensive and precise functional test of the clotting system, we designed a cross-sectional, single-center study involving 83 patients with rare bleeding disorders (RBDs) to compare the usefulness of the thrombin generation (TG) assay versus conventional tests including prothrombin time (PT) and activated partial thromboplastin time (aPTT) in predicting bleeding risk in patients with RBD in southern Iran. The TG parameters consisted of endogenous thrombin potential, lag time, peak, time to peak (ttPeak), and start tail. The area under the receiver-operating characteristic (ROC) curve showed statistically significant associations between bleeding risk and lag time, ttPeak, and start tail. We determined cutoff values for these 3 TG parameters and obtained a negative predictive value of 86% to 90% in patients with RBD who had a bleeding score (BS) ≤13. The ROC curves for the association of PT and aPTT with BS did not indicate any significant association. Correlation analysis supported the results of ROC curve analysis, only lag time, ttPeak, and start tail showed significant positive correlations with BS (P < .05). Disease severity based on plasma factor activity was significantly associated with prolonged lag time and ttPeak and with prolonged PT (P <.05). We suggest that TG assay is a potentially more useful tool for predicting the bleeding risk in patients with RBD. However, the small sample size in different RBD subgroups precluded subgroup analysis. Prospective multicenter studies with larger numbers of patients are therefore advisable., (© The Author(s) 2013.)

This is a retrospective study on six multiple myeloma patients with upfront coagulopathy and bleeding. A detailed description and analysis of clinical characteristics, coagulation factor deficiencies, treatments and outcome of those six multiple myeloma patients are presented. All six patients presented with significant bleeding. One patient was detected with single factor X deficiency and another with single factor VII (FVII) deficiency, whereas four other patients had complex factor deficiencies. The time from symptom presentation to diagnosis ranged from 3 to 10 months. After correct diagnosis and coagulation factor supplementation, those patients were treated with bortezomib/adriamycin/dexamethasone (PAD) or melphalan/dexamethasone/thalidomide (MTD) regimen. It took 29-71 days (median time 46 days) to completely correct coagulation factor deficiencies since the start of therapy for multiple myeloma. Multiple myeloma patients with acquired bleeding disorders may present with large, deep and multiple sites of haematoma or other types of significant bleeding, which may affect bone marrow examination in some of the cases. Patients may be easily misdiagnosed. The routine examinations of erythrocyte sedimentation rate, serum immunoglobulins and blood urine light chain are the key to diagnosis, hence requiring the treating physician to think broadly and look for traits suggesting myeloma as the underlying cause.

Thrombin is a key enzyme of the coagulation system, having both pro- and anticoagulant functions. Thus, the generation of thrombin is one of the most important steps in coagulation. Global haemostasis assay, the so-called thrombin generation test is appropriate for its assessment. Since thrombin generation is sensible for both pro- and anticoagulant processes it can be applied for the general characterisation of the risk of thrombosis and bleeding, too. Clinical studies confirmed augmented thrombin generation in patients with high risk of venous or arterial thrombosis. Anticoagulant therapy (also novel oral anticoagulant treatment) can be monitored by thrombin generation. In case of haemophilia thrombin generation assays reflect bleeding severity. It is applicable for monitoring of both conventional haemophilia treatment and inhibitor-bypassing therapy, which is needed when inhibitors develop in patients. Standardization of thrombin generation methods and determination of cut off values are required before its application in clinical practice.

Congenital rare factor deficiencies may present in infancy by life-threatening bleedings or may not show any symptoms until adulthood. It is reported more commonly in countries having consanguineous marriages. Data regarding surgical interventions of rare congenital factor deficiencies are based on case reports and records of guidelines. There are no well documented and separately prepared directories related to pre-surgical and prophylactic approaches of surgical interventions of these deficiencies. Our retrospective study consisted of 171 rare factor deficiencies that were followed up in our clinic, and of whom 61 had 88 surgical interventions between 1990 and 2012. Of these patients, 45 were having factor VII deficiency, and factor V, X, XI, XIII and fibrinogen deficiencies were present in five, four, three, two and two patients, respectively. In 23 patients, factor coagulant activities were under 5% (37.7%), in 15 it was between 5 and 30% (24.6%), and in 23 between 30 and 50% (37.7%). Twenty-eight were symptomatic and 33 were asymptomatic. Information of 51 (83.6%) male and 10 (16.4%) female patients with an age range of 5-25 years (13 ± 5.27), whose age at presentation ranged between 3 weeks and 18 years (7 ± 4.66), were retrieved from patient records and from the records contained in the data-processing environment introduced in 2005. The rate of familial consanguinity was 49.2%. Of the surgical interventions, 24 (27.3%) were major, 24 (27.3%) were minor and 40 (45.4%) were circumcision. We used fresh frozen plasma in 32, recombinant factor (rF)VIIa in 20, prothrombin complex concentrate in five and fibrinogen in three patients during surgical interventions. In 18 patients, antifibrinolytic agents were also used. In 27 patients, surgical interventions were applied without any replacement therapy. No additional doses were required after surgical prophylaxis doses. Thrombotic events were not observed. Antibody occurrence was not detected in these patients. In our study, we evaluated preparation for surgical procedures, factor replacement therapy before surgical intervention and postoperative follow-up in patients with rare coagulation factor deficiency.

Background: Dysfibrinogenemia is a rare group of qualitative fibrinogen disorders caused by structural abnormalities in the fibrinogen molecule. The laboratory diagnosis of dysfibrinogenemia is controversial. Fibrinogen Paris V, clinically termed Dusart Syndrome, is a dysfibrinogenemia caused by a single base substitution in the gene coding for the Aα-chain of the fibrinogen molecule., Objectives: To diagnose the first Scandinavian family with Fibrinogen Paris V affecting several family members; the proband, a seven-year-old boy with cerebral vein thrombosis., Methods: The diagnosis was established following the ISTH guideline for laboratory testing supplemented with fibrin structure analysis and fibrinogen gene analysis., Results: Prolonged thrombin time and reduced ratio between the functional and the protein concentration of fibrinogen were observed in four family members who also were characterized by significantly reduced fibrin polymerization (p < 0.001), reduced fibrin fibre diameter (p < 0.001), reduced fibrin mass-length ratio (p < 0.001) and significantly reduced t-PA-induced fibrinolysis of the fibrin clots (p < 0.001) when compared to controls. Fibrinogen gene analysis demonstrated that five of the family members carried the Fibrinogen Paris V mutation. All laboratory tests were normal in the family members carrying the wild type of the fibrinogen gene. Four of the affected patients had suffered from thrombotic episodes. A noticeable feature in the present family was the presence of both venous and arterial thrombosis., Conclusions: Excellent concordance was observed between the screening and confirmatory tests, fibrin structure analysis and fibrinogen gene analysis. Fibrin structure analysis should be considered in the laboratory algorithm for diagnosis of dysfibrinogenemia.

Background: The outcomes of colorectal cancer are determined by host factors, including systemic inflammation. The purpose of this study was to evaluate the prognostic significance of fibrinogen and inflammation-based scores, as markers of the inflammatory response, in colon cancer., Methods: We retrospectively reviewed the medical records of patients with nonmetastatic colon cancer who underwent curative resection between January 2005 and December 2007. Fibrinogen, albumin, C-reactive protein, neutrophil, lymphocyte, and platelet counts were measured at the time of diagnosis. Correlations between preoperative plasma fibrinogen levels and clinicopathologic characteristics were analyzed. Univariate and multivariate survival analyses were performed to identify factors associated with disease-free and overall survival., Results: A total of 624 patients who underwent curative resection for colon cancer were eligible for this study. Mean preoperative plasma fibrinogen levels were 325.24±88.19 mg/dl. Higher preoperative plasma fibrinogen levels were associated with sex (male), old age, poorly/mucinous differentiated tumor, advanced tumor stage, elevated carcinoembryonic antigen (CEA) levels, higher modified Glasgow Prognostic Score, and higher neutrophil:lymphocyte and platelet:lymphocyte ratios. In multivariate analysis, elevated plasma fibrinogen level [disease-free survival: hazard ratio (HR) 1.999, 95% confidence interval (95% CI) 1.081-3.695, P=.027; overall survival: HR 3.138, 95% CI 1.077-9.139, P=.036], advanced tumor stage, and higher CEA levels were independently associated with worse disease-free survival and overall survival. None of the inflammation-based scores were significantly associated with survival., Conclusions: Fibrinogen as one of inflammatory markers may be considered a possible prognostic marker in colon cancer.

The investigation of inherited bleeding disorders with routine tests of hemostasis will yield clear diagnostic information in the majority of subjects with an unequivocal history of bleeding and especially in those where the phenotypic severity is severe and where an obvious family history of bleeding is present. Nevertheless, a significant minority of subjects with obvious bleeding symptoms will remain without a definite diagnosis after extensive hemostatic testing. With these facts in mind, the role of molecular testing for inherited disorders of hemostasis now includes the following: confirmation of a phenotypic diagnosis through targeted genetic analysis, the distinction of bleeding phenocopies by molecular analysis, and provision of genetic testing as the investigation of choice in situations such as prenatal diagnosis and detection of the carrier state for inherited bleeding traits. In addition, molecular testing can sometimes be used to provide supplementary knowledge that can be used to enhance clinical care. Finally, the utility of genome-wide approaches to identify novel genetic associations may provide new information to explain the cause of bleeding in the population of bleeders without established diagnoses., (© 2013 Blackwell Publishing Ltd.)

The Q analyzer is a recently launched fully automated photo-optical analyzer equipped with primary tube cap-piercing and capable of clotting, chromogenic, and immunoturbidometric tests. The purpose of the present study was to evaluate the performance characteristics of the Q analyzer with reagents from the instrument manufacturer. We assessed precision and throughput when performing coagulation screening tests, prothrombin time (PT)/international normalized ratio (INR), activated partial thromboplastin time (APTT), and fibrinogen assay by Clauss assay. We compared results with established reagent instrument combinations in widespread use. Precision of PT/INR and APTT was acceptable as indicated by total precision of around 3%. The time to first result was 3  min for an INR and 5  min for PT/APTT. The system produced 115 completed samples per hour when processing only INRs and 60 samples (120 results) per hour for PT/APTT combined. The sensitivity of the DG-APTT Synth/Q method to mild deficiency of factor VIII (FVIII), IX, and XI was excellent (as indicated by APTTs being prolonged above the upper limit of the reference range). The Q analyzer was associated with high precision, acceptable throughput, and good reliability. When used in combination with DG-PT reagent and manufacturer's instrument-specific international sensitivity index, the INRs obtained were accurate. The Q analyzer with DG-APTT Synth reagent demonstrated good sensitivity to isolated mild deficiency of FVIII, IX, and XI and had the advantage of relative insensitivity to mild FXII deficiency. Taken together, our data indicate that the Q hemostasis analyzer was suitable for routine use in combination with the reagents evaluated.

Background: Coagulopathic bleeding is a leading cause of in-hospital death after injury. A recently proposed transfusion strategy calls for early and aggressive frozen plasma transfusion to bleeding trauma patients, thus addressing trauma-associated coagulopathy (TAC) by transfusing clotting factors (CFs). This strategy may dramatically improve survival of bleeding trauma patients. However, other studies suggest that early TAC occurs by protein C activation and is independent of CF deficiency. This study investigated whether CF deficiency is associated with early TAC., Methods: This is a prospective observational cohort study of severely traumatized patients (Injury Severity Score ≥ 16) admitted shortly after injury, receiving minimal fluids and no prehospital blood. Blood was assayed for CF levels, thromboelastography, and routine coagulation tests. Critical CF deficiency was defined as ≤ 30% activity of any CF., Results: Of 110 patients, 22 (20%) had critical CF deficiency: critically low factor V level was evident in all these patients. International normalized ratio, activated prothrombin time, and, thromboelastography were abnormal in 32%, 36%, and 35%, respectively, of patients with any critically low CF. Patients with critical CF deficiency suffered more severe injuries, were more acidotic, received more blood transfusions, and showed a trend toward higher mortality (32% vs. 18%, p = 0.23). Computational modeling showed coagulopathic patients had pronounced delays and quantitative deficits in generating thrombin., Conclusions: Twenty percent of all severely injured patients had critical CF deficiency on admission, particularly of factor V. The observed factor V deficit aligns with current understanding of the mechanisms underlying early TAC. Critical deficiency of factor V impairs thrombin generation and profoundly affects hemostasis.

Antithrombin (AT), in the presence of heparin, is able to inhibit the catalytic activity of factor VIIa bound to tissue factor (TF) on cell surfaces. The clinical meaning of FVIIa-AT complexes plasma levels is unknown. It was the objective of this study to evaluate FVIIa-AT complexes in subjects with thrombosis. Factor VIIa-AT complexes plasma levels in 154 patients consecutively referred to our Department with arterial or venous thrombosis and in a group of 154 healthy subjects, were measured. Moreover, FVIIa-AT complexes were determined in: i) n = 53 subjects belonging to 10 families with inherited factor VII deficiency; ii) n = 58 subjects belonging to seven families with AT deficiency; iii) n = 49 patients undergoing oral anticoagulant therapy (OAT). Factor VIIa-AT levels were determined by a specific ELISA kit (R&D, Diagnostica Stago, Gennevilliers, France). Factor VIIa-AT complexes mean plasma levels were lower in patients with either acute arterial (136 +/- 40 pM) or venous (142 +/- 53 pM) thrombosis than subjects with previous thrombosis (arterial 164 +/- 33 pM and venous 172 +/- 61 pM, respectively) and than healthy controls (156 +/- 63 pM). Differences between acute and previous thrombosis, were statistically significant (p < 0.05). Subjects with inherited and acquired (under OAT) factor VII deficiency had statistically significant lower FVIIa-AT complexes plasma levels (80 +/- 23 pM and 55 +/- 22 pM, respectively) than controls (150 +/- 51 pM, p < 0.0001 and 156 +/- 63 pM, p < 0.00001, respectively). Factor VIIa-AT complexes are positively correlated with plasma factor VII/VIIa levels. Further investigations are needed to verify the possible role of higher FVIIa-AT complex plasma levels in predicting hypercoagulable states and thrombosis.

Thrombin generation is thought to be mediated predominantly by the tissue factor or ''extrinsic'' coagulation pathway. An alternate pathway to thrombin generation (the ''intrinsic'' pathway or contact system) has been observed when blood or plasma comes in contact with artificial surfaces. Here we present evidence for a new route to thrombin formation that begins with the activation of the contact system protein prekallikrein by oversulfated heparin (OS-HB). Kallikrein, instead of activated factor X, cleaves prothrombin to form thrombin. Thrombin then cleaves fibrinogen to form fibrin clots. Moreover, we show that OS-HB by-products induce kallikrein- and thrombin-like activities in normal human plasma and in human plasma devoid of coagulation factor X or downstream contact system components factor IX or factor XI. Oversulfated heparin by-product-induced thrombin generation may have had a role in the adverse reactions associated with the recent clinical use of contaminated heparin.

Objective: To correlate blood coagulation factor levels with disease severity in cirrhotic patients evaluated as candidates for liver transplantation., Material and Method: We included 87 patients (75.9% men) with a mean age of 54+/-9.4 years. Etiology and Child-Turcotte-Pugh (CTP) class were as follows: alcohol-related (36.8%), hepatitis C virus infection (35.6%), hepatitis B virus infection (11.5%) and other (16.1%); class A (13.8%), class B (40.2%) and class C (46%), respectively. The mean value of the Model for End-Stage Liver Disease (MELD) score was 14.5+/-5.9. Levels of factors II, V, VII, VIII, IX and X were compared between each CTP grade and with the MELD score., Results: Except for factor VIII, all the clotting factors were reduced in our series (in particular factors II, V and VII) and deficiencies in these factors were closely related to CTP grade with statistical significance for stage C (p <0.05). We also found a marked inverse correlation between the MELD score and factors II, V, VII, IX and X values (p <0.05)., Conclusions: A correlation was found between reduced levels of factors II, V, VII, IX and X in liver cirrhosis and the severity of liver disease.

We studied the prevalence of acquired and genetic thrombophilia in 198 women with recurrent fetal loss who were having three or more than three abortions. Seventy-nine women had only early pregnancy losses, that is, first trimester abortions, 30 women had only late pregnancy losses, that is, second and third trimester abortions whereas 89 had both early and late pregnancy losses. The control group included 100 age-matched fertile parous women who did not have any obstetric complications and had at least one normal healthy child. Several genetic and acquired thrombophilia markers were studied. The strongest association was observed with anticardiolipin (odds ratio 22.6, confidence interval 5.7-89, P = 0) followed by lupus anticoagulant, anti-beta2 glycoprotein-1, antiannexin. Association of antiphospholipid antibody syndromes was detected with the time of pregnancy loss in anticardiolipin, lupus anticoagulants, which was significantly associated with early pregnancy loss as compared with second and third trimester loss. In case of beta2 glycoprotein-1, antiannexin it was less significantly associated with early pregnancy loss as compared with second and third trimester loss. The risk of fetal loss with protein S deficiency was the highest risk observed for any heritable thrombophilia, followed by protein C, factor V Leiden, endothelial protein C receptor, antithrombin III deficiency and beta448 fibrinogen polymorphism. Modest risks were also observed with 5,10-methylenetetrahydrofolate reductase, plasminogen activator inhibitor 4G/4G polymorphisms and beta448 fibrinogen polymorphism. A combination of two or more than two genetic risk factors were observed in 55 (27.7%), whereas the genetic and acquired risk factors were observed in 107 (54%) of the cases. Thrombophilia is an important contributing factor for both early and late pregnancy losses; approximately two-thirds of our cases of unexplained fetal losses could be explained by acquired or heritable thrombophilia or both, which is in line with other western studies.

The modern thrombin generation tests describe different phases of generation of thrombin that is initiation, amplification and inhibition of thrombin generation as well as the integral amount of generated thrombin. We investigated 55 patients with congenital deficiencies of different coagulation factors and analysed the relationship between the nature and the concentration of clotting factors, with different parameters of thrombin generation curve that is lag time, peak, time to peak and the area under curve or endogenous thrombin potential. The endogenous thrombin potential was unaffected by severe deficiency of factors XI and XII, and reduced in factor IX, VII and factor V and VIII deficiencies. The lag time was significantly prolonged in cases of severe factor VII, X and V deficiencies, and was almost normal in cases of factors VIII, IX, combined factors V and VIII, factor XI, XII and XIII deficiencies. The peak height was severely affected in cases of severe factor X, V, VIII and IX deficiency and combined deficiency of multiple vitamin K dependant coagulation factors, and significantly reduced in factor VIII, V, X, XIII and combined vitamin K deficiency.In all the patients with less than 40% thrombin generation, the clinical symptoms were severe. Bleeding symptoms were restricted to epistaxis and ecchymosis when thrombin generation was more than 90% of the normal. In the cases of combined deficiency of factors V and VIII all the values were intermediate as they exhibit mild deficiencies of both factors V and VIII and correlated well with the clinical symptoms. Endogenous thrombin potential of inherited isolated deficiencies of coagulation factors may thus provide an interesting insight about involvement of the deficient factor(s) at different phases of thrombin generation.

Desmopressin (DDAVP) affects haemostasis by the release of von Willebrand factor and coagulation factor VIII from endothelium. The aim of the study was to evaluate the results of DDAVP testing in paediatric patients with congenital bleeding disorders. Forty-one patients consisting of children with von Willebrand's disease (VWD, n = 26) and platelet function defects (PFD, n = 15) received DDAVP intravenously at a dosage of 0.3 mug/kg over 30 min. FVIII activity (FVIII), von Willebrand factor antigen (VWF:Ag), collagen-binding activity (VWF:CB) and PFA 100((R)) closure times (CT) were measured before, 60, 120 and 240 min after DDAVP. In VWD, the VWF:Ag increased threefold until 60 min and then it decreased continuously. Compared with baseline, VWF:Ag was significantly higher at 60 and 120 min but not at 240 min. In contrast, in PFD, the peak of VWF:Ag was reached after 120 min. Two hundred and forty minutes after DDAVP, the mean was still significantly elevated compared with baseline values. The course of VWF:CB corresponded to that of VWF:Ag. In patients with VWD and PFD, FVIII rose two- to threefold within 2 h after DDAVP. CT in patients with VWD shortened markedly within 120 min and then rose again. In all children with PFD, except one non-responder, the CT shortened within 240 min after DDAVP. Two non-responders with VWD were identified by the failed increase of VWF:Ag, VWF:CB and by prolonged CT. Haemostatic effects of DDAVP differ interindividually and dependent on the coagulation disorder. DDAVP was effective in most, but not in all patients. DDAVP testing is recommended to determine the individual haemostatic response.

The thrombin generation test is used to study coagulation in patients with haemorrhagic diseases or with high thrombotic risk. To our knowledge, this is the first study investigating the relative influence of coagulation factors on thrombin generation in plasma. The aim was to investigate the influence of coagulant factors, anticoagulant factors, and tissue factor (TF) on three parameters: endogenous thrombin potential (ETP), peak thrombin concentration, and lag time for the appearance of thrombin. At a low TF concentration, all factors except factor XI influenced thrombin generation. At a high TF concentration, only the factors of the extrinsic pathway exerted an influence. ETP and peak thrombin were linearly correlated to factor II concentration. Factor V and factor VII effects increased hyperbolically with factor concentration. The influence of factor X on thrombin generation depended on TF concentration. In the absence of factor VIII and factor IX, ETP fell to 60-70% of the normal when peak thrombin fell to 25-30% of the normal. Fibrinogen concentration influenced ETP and peak thrombin and decreasing fibrinogen levels shortened the lag time. As expected, decreasing antithrombin concentration caused dramatic increases in thrombin generation. Protein S prolonged the lag time, especially at a low TF concentration. No effect of protein C was observed, likely due to the absence of thrombomodulin. The thrombin generation test was more sensitive to factor deficiencies at low than at high TF concentration. ETP was not the most critical parameter for studying coagulation factor deficiencies. Instead, peak thrombin was the most sensitive parameter.

Introduction: The aim of this study was to assess the usefulness of different aPTT assays and the ecarin chromogenic assay reaction time (ECA) for measurement of argatroban concentration in plasma from healthy persons as well as in different patient subgroups., Methods: We spiked plasma samples from healthy individuals, patients under oral anticoagulation (OAT) or with liver dysfunction (LD) with increasing argatroban concentrations (0-2000 ng/ml) and performed 4 different aPTTs assays and the ECA., Results: Depending on argatroban concentrations aPTTs increased in a curvilinear fashion; in plasma from healthy individuals means of calculated argatroban concentration at 2-fold aPTT differed extensively depending on the aPTT reagent used (725 ng/ml to 1136 ng/ml) and were even more pronounced in plasma from coagulation factor deficient patients (460 ng/ml in patients with LD vs. 1172 ng/ml in patients with OAT), whereas ECA showed linear argatroban influence and reliable results in all subgroups., Conclusions: Because of wide differences in aPTT measurements depending on the aPTT reagent used, interindividual variations and different clinical conditions the aPTT is not the method of choice for monitoring argatroban and the ECA should be preferred.

Oxidized cellulose is an effective hemostat that works naturally to aid in blood coagulation. The mechanism of its action is not very well understood. Little effect on blood coagulation, but a pronounce decrease in platelet count has been reported upon the addition of the oxidized cellulose to the whole blood. As a marker of platelet activation and aggregation we used serotonin release reaction and turbidity changes in time. We found that oxidized cellulose did not activate washed platelets reconstituted in plasma-free medium or plasma-free medium with fibrinogen; no reduction of platelet count was observed. Serotonin release in platelet-rich plasma incubated with oxidized cellulose started in the range from 5 to 10 min. Serotonin release from platelets reconstituted in plasma deficient in either coagulation factor V, VIII, IX, or XII was delayed. Blood platelets activation by oxidized cellulose requires calcium ions present in dispersion of oxidized cellulose. Factor XIII deficiency had no influence on blood platelets activation by oxidized cellulose. Our results clearly indicate the significance of intrinsic coagulation pathway activation on blood platelets activation by oxidized cellulose and so indirectly on the hemostyptic effect of oxidized cellulose.

Disorders of coagulation in children often prove challenging to the medical care team. The aims of this study were to assess the spectrum and prevalence of coagulation disorders among children attending Mansoura University Children Hospital (MUCH), Mansoura, Egypt. A total of 105 pediatric patients were referred to MUCH. They were divided into two groups: congenital coagulation disorders (75 cases, age 45.36 +/- 48.59 months), and acquired coagulation disorders (30 cases, age 56.13 +/- 61.61 months). All patients were subjected to thorough history taking including the nature of bleeding, family, past history, mode of inheritance, and detailed physical findings. Hemostatic tests included: platelet count, bleeding time (BT), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT). Specific tests in the congenital group include assay of coagulation factors according to each disorder, Von Willebrand factor assay, ristocetin aggregation test, APTT mixing study for detection of inhibitors in complicated hemophilia cases, F VIII C to VWAg ratio with cut off 0.7 for detection of carriers in some hemophilia A families. Congenital disorders constituted 71.4% of the studied cases vs. 28.6% for acquired disorders. Hemophilia A (42.85%), hemophilia B (14.28%) and liver diseases (14.28%) represented the majority of the studied cases. Mild and moderate cases of hemophilia A and B are more frequent than severe cases in both types. Male sex is more frequent than female in the congenital group (94.7 vs. 5.3%, P < 0.001). Direct correlation existed between factor level assay and severity of hemophilia (r = 0.73, P = 0.006). Three mothers and one sister were identified as carrier out of four families. Anti-clotting factors inhibitor was detected in 18.2% of patients with hemophilia A and in 9.1% with hemophilia B. In conclusion, our study found that hemophilias are the most prevalent congenital coagulation disorders among children. Attention must be given for detection of hemophilia carriers and inhibitors of clotting factors.

Background and Objectives: Mucocutaneous bleeding (MCB) is the main expression of inherited disorders of primary hemostasis. However, the relative prevalence of these disorders, their clinical differential diagnosis, and the proportion of patients with MCB of unknown cause (BUC) after an initial comprehensive laboratory testing are unknown., Design and Methods: We studied prospectively 280 consecutive patients with MCB and 299 matched controls, using strict inclusion and exclusion criteria. A single physician recorded the clinical data in a bleeding score and estimated the severity of bleeding in clinical categories. Laboratory criteria for the diagnosis of von Willebrand's disease (VWD) and platelet function defects were established from reference values derived from controls., Results: Fifty patients (17.9%) had VWD (type 1VWD=45, type 2=5). Platelet function defects and mild clotting factor deficiencies were found in 65 (23.2%) and 11 (3.9%) patients, respectively. Thirteen (11.5%) patients had combined defects. The remaining 167(59.6%) patients had BUC, with prolonged bleeding time in 18.6% as their only abnormality. All these disorders, including BUC, were clinically undistinguishable. Moreover, no relationship was found between the severity of bleeding and VWF/platelet function variables., Interpretation and Conclusions: The diagnostic efficacy of a first laboratory testing in patients with hereditary MCB is 40.4%. Most patients have a disease(s) of high prevalence but unknown pathogenesis. Concurrent bleeding disorders in the same patient are frequent. Our results support the proposal that low plasma VWF levels, but also platelet function defects, should be considered risk factors rather than unequivocal causes of hemorrhages.

The fibrinogen Aalpha R16C mutation is a common cause of dysfibrinogenaemia and has been previously associated with both bleeding and thrombosis. However, the mechanism underlying the thrombotic phenotype has not yet been elucidated. This report characterises the defect in fibrinolysis seen as a result of the Aalpha R16C mutation. A young patient with dysfibrinogenaemia (fibrinogen Hershey III) was found to be heterozygous for the Aalpha R16C mutation. Functional assays were performed on the purified fibrinogen to characterise clot formation and lysis with plasmin and trypsin. Consistent with previous results, clot formation was diminished. Unexpectedly, fibrinolysis was also delayed. Plasminogen activation was normal, ruling out decreased plasmin generation as the mechanism behind the fibrinolytic resistance. Western blot analysis showed no difference in the amount of bound alpha2-antiplasmin or albumin. When clot lysis was assayed with trypsin substituted for plasminogen, a significant delay was also observed, indicating that defective binding to plasminogen could not explain the fibrinolytic resistance. These results suggest that the defective fibrinolysis is due to increased proteolytic resistance, most likely reflecting changes in clot structure.

We tested the hypothesis that Chinese patients have a coagulation profile that is less prothrombotic than that of Caucasian counterparts after the Fontan procedure by determining the type and prevalence of anticoagulant and procoagulant deficiencies in Chinese patients and comparing the findings to those previously reported in Caucasian series. The liver function and coagulation factors were assessed in 21 ethnic Chinese patients, aged 17.0 +/- 5.6 years, at 10.7 +/- 4.0 years after the Fontan procedure. The results were compared to those of 21 age-matched Chinese controls with minor congenital heart disease. The prevalence of coagulation factor deficiencies in our patients was further compared to that reported in Caucasian patients. When compared with controls, patients had significantly lower protein C (p = 0.014), factors II (p = 0.024), V (p < 0.001), VII (p < 0.001), IX (p = 0.036), and X (p < 0.001), and higher bilirubin (p = 0.001) levels. The prevalence of protein C deficiency was 9.5%, whereas those of factor II, V, VII, IX, and X deficiencies were 0, 66.7, 9.5, 0, and 57.1%, respectively. When compared with Caucasian data, our data showed a significantly lower prevalence of protein C, total protein S, antithorombin III, factor II, and factor VII deficiencies. Furthermore, the previously reported increase in factor VIII levels was not found. In contrast, the prevalence of factor X deficiency was higher in our patients. This study provides the first evidence of ethnic differences in coagulation factor abnormalities after the Fontan procedure. The imbalance between procoagulant and anticoagulant pathways in Chinese patients favors a bleeding, rather than a thrombotic, tendency.

The sensitivity of commercial prothrombin time (PT) tests was assessed based on a dilution series of equine pooled plasma (EPP) (experiment 1) and on 40 equine plasma samples with reduced activity of coagulation factors II, V, VII and X (experiment 2). Two different PT reagents (reagent 1, human placental thromboplastin; reagent 2, recombinant human tissue factor) were used according to the manufacturers' instructions (standard test, PT([ST])) and compared to a modified test procedure (modified test, PT([MT])) using sample dilution and fibrinogen addition. In all samples, sensitivity was lower (P<0.01) when using PT([ST]) with reagent 2 (0.20) than when using either PT([ST]) with reagent 1 (0.65) or PT([MT]) with both reagents (reagent 1, 0.60-0.75, reagent 2, 0.58-0.70, depending on sample dilution). The highest sensitivity was found for PT([MT]) when using a 1:20 sample dilution. In those samples in which at least one coagulation factor activity was decreased (by 20%; n=18), the sensitivity of PT([ST]) with reagent 2 (0.33) was found to be inadequate, in contrast to all other test procedures (0.83-0.94). This low sensitivity corresponded to shorter time intervals between different coagulation activity levels prepared by EPP dilution. The results indicate that adequate sensitivity of PT measurements in equine plasma can be achieved using a standard test procedure as long as a suitable reagent is used.

Inherited thrombophilia can be defined as a genetically determined predisposition to the development of thromboembolic complications. Since the discovery of activated protein C resistance in 1993, several additional disorders have been described and, at present, it is possible to identify an inherited predisposition in about 60 to 70% of patients with such complications. These inherited prothrombotic risk factors include qualitative or quantitative defects of coagulation factor inhibitors, increased levels or function of coagulation factors, defects of the fibrinolytic system, altered platelet function, and hyperhomocysteinemia. In this review, the main inherited prothrombotic risk factors are analyzed from epidemiological, laboratory, clinical, and therapeutic points of view. Finally, we discuss the synergism between genetic and acquired prothrombotic risk factors in particular conditions such as childhood and pregnancy.

Patients with hereditary hemostatic disorders, characterized by a tendency to bleeding or thrombosis, constitute a serious challenge in the dental practice. Advances in the medical diagnosis of hemostatic disorders have exposed dental professionals to new patients not amenable to the application of the management protocols associated with other, more well-known, disorders. It is the aim of this paper to review the evidence, to highlight the areas of major concern, and to suggest management regimens for patients with hereditary hemostatic disorders. An extensive review has been made (PubMed, Science Direct, Web of Knowledge, etc.) of literature pertaining to hereditary disorders affecting blood coagulation factors and how they affect the practice of dentistry. Several aspects relating to the care of such patients must be recognized and taken into consideration when dental treatment is planned. Replacement of deficient coagulation factors ensures that safe dental treatment will be carried out. However, the half-life of such coagulation factors requires that dental treatment be specifically planned and adapted to the type of pathology involved.

Objectives: To study the effect of an intensive programme to modify life-style on levels of plasma fibrinogen in patients without cardiovascular pathology, with high fibrinogen and normal cholesterol levels. To analyse whether the effect on fibrinogen is independent, or otherwise, of the effect on lipids., Design: Randomised clinical trial with a control., Setting: 11 health districts in L'Hospitalet de Llobregat and Barcelona., Participants: 436 patients will be included, 218 individuals between 35 and 75 years old in each group, and without cardiovascular pathology (ischaemic cardiopathy, cerebral vascular accident or peripheral arteriopathy), with hyperfibrinogenaemia (fibrinogen > 300 mg/dL) and with plasma control < 250 mg/dL., Interventions: One group of patients will receive an intensive intervention (in frequency and intensity of counselling and treatment) for life-style changes, i.e. stopping smoking, low-calorie diet in case of overweight or obesity, and physical exercise. The follow-up of the intervention group will be every 2 months. The control group will follow customary treatments., Measurements: Levels of plasma fibrinogen. In addition, other relevant events will be recorded over a 2-year monitoring period: modification of risk factors, changes in quality of life, cardiovascular events or death., Discussion: The introduction of an intensive primary prevention intervention (life-style changes) in patients with hyperfibrinogenaemia could be a more effective measure than the habitual intervention for reducing plasma fibrinogen figures. In addition, these measures could be translated into a reduction of cardiovascular risk and an improvement in the patient s quality of life.

Background: Thrombelastography (TEG) is used to assess coagulopathy. However, a comprehensive characterization of the effects of specific coagulation factor deficiencies and mode of activation on TEG data does not exist., Methods: Thrombelastography was performed for 15 min with control plasma and plasmas deficient (<1% activity) in Factors II, V, VII, VIII, IX, X, XI, XII, or XIII activated with celite (0.28 mg ml(-1)) or tissue factor (TF, 0.1%) (n = 6 per condition). Additional fibrinogen concentration activity (75-345 mg dl(-1)) and Factor II, VII, X and XII activity-response relationships (1%, 6.25%, 12.5%, 25%, 50% and 100% activity) were obtained (n = 8 per condition). Thrombelastography parameters included reaction time (R), angle (alpha), and clot strength (A, amplitude; G, elastic modulus)., Results: Celite activation of FXII-deficient plasma, TF activation of FVII-deficient and FX-deficient plasma, and celite or TF activation of FII-deficient plasma resulted in an almost undetectable clot. Compared to control values, celite activation of plasmas deficient in FXI, FIX and FVIII resulted in prolonged R and decreased alpha values, whereas TF activation resulted in decreased alpha values. Celite and TF activation of FV-deficient plasma resulted in prolonged R and decreased alpha values, whereas FXIII-deficient plasma had decreased alpha, A and G-values compared to control values., Conclusions: The fundamental finding of this study is that coagulation factor deficiencies affect TEG parameters in both a factor-dependent and activation-dependent fashion. Utilizing both celite and TF activation improves the diagnostic power of TEG. Based on such TEG data, more targeted administration of blood products could potentially help improve perioperative hemostatic outcomes.

Combined deficiency of factor (F)V and FVIII (F5F8D) and combined deficiency of vitamin K-dependent clotting factors (VKCFD) comprise the vast majority of reported cases of familial multiple coagulation factor deficiencies. Recently, significant progress has been made in understanding the molecular mechanisms underlying these disorders. F5F8D is caused by mutations in two different genes (LMAN1 and MCFD2) that encode components of a stable protein complex. This complex is localized to the secretory pathway of the cell and likely functions in transporting newly synthesized FV and FVIII, and perhaps other proteins, from the ER to the Golgi. VKCFD is either caused by mutations in the gamma-carboxylase gene or in a recently identified gene encoding the vitamin K epoxide reductase. These two proteins are essential components of the vitamin K dependent carboxylation reaction. Deficiency in either protein leads to under-carboxylation and reduced activities of all the vitamin K-dependent coagulation factors, as well as several other proteins. The multiple coagulation factor deficiencies provide a notable example of important basic biological insight gained through the study of rare human diseases.

Background: The prothrombin time (PT), also called thromboplastin time ("Quick"), is usually measured using citrated plasma from venous blood. Recently, portable coagulation monitors have been developed, which measure PT using non-anticoagulant capillary whole blood from a finger stick. In the present study, we compared the International Normalized Ratio (INR) of the standard laboratory method (INRven) with the newly developed reagent PT(N) for the CoaguChek Pro portable monitor (INRcap) in various patient groups: healthy individuals, patients with oral anticoagulation and patients with a deficiency of coagulation factor V, factor VII or factor X, respectively., Methods: One hundred and fifty-five patients were included in this prospective open comparison study. Capillary PT was measured with the portable coagulation monitor CoaguChek Pro using the new disposable cartridge PT(N) (containing rabbit brain thromboplastin). In comparison, PT was measured using citrated venous plasma and the reagent Innovin on the coagulation analyzer STA-R., Results: We found a correlation coefficient of 0.85 between capillary and venous INR values among the 100 patients with oral anticoagulation. The slope of the regression line was 1.4 and the y-intercept is -0.65. Agreement between both methods was found to be 80% (95% CI: 72-88%) and the standard-agreement was 85% (95% CI: 78-92%). Among the 30 healthy subjects, the individual differences between INRven and INRcap were in 4 cases 0, in 21 cases 0.1 and in 5 cases 0.2., Conclusion: The new test cartridge PT(N) was found to be a valuable tool for measuring PT among healthy subjects. However, among patients with oral anticoagulation, agreement between INRcap measured with the new cartridge PT(N) and INRven was only moderate. Our results show that improvements are necessary for a more valuable measurement of capillary PT with portable coagulation monitors.

Until now, no routinely used clotting assay has demonstrated the power to reflect significantly a patient's response to recombinant factor (rF)VIIa. Adopting a thrombelastographic principle, profiles of continuous whole blood (WB) coagulation were studied in minimally altered WB activated with a small amount of tissue factor (TF). Investigation of the WB clotting profile was performed before and after ex vivo addition of rFVIIa 20 nm to WB from 26 patients with hemophilia A, two patients with severe hemophilia B, and individuals with deficiencies of FV, FX, FXI, and FXIII. In five patients with hemophilia plus inhibitors, the response to ex vivo added rFVIIa and to activated complex concentrate (APCC) was studied. Patients with severe and moderate hemophilia A demonstrated remarkable variance in the hemostatic characteristics at baseline, even in groups with the same FVIII:C activity levels. The response to rFVIIa at 20 nm also varied extensively, the effect correlating with the continuous WB coagulation phenotype at baseline. This indicates that the efficacy of rFVIIa may be optimized by tailoring the dose according to the hemostatic response to varying doses tested prior to in vivo administration. In patients with inhibitors against FVIII and factor IX, rFVIIa and APCC substitution resulted in quite similar response patterns that appeared to be dose dependent. In severe FV, FX, and FXIII-deficient WB, rFVIIa addition induced minor changes only. In FXI deficiency, rFVIIa normalized the dynamic properties of clotting, although a reduced clot firmness remained unchanged. In conclusion, the thrombelastographic analysis of WB clotting, as activated with a minute amount of TF, seems an interesting method that detects phenotypic variation amongst hemophilia patients. The method appears useful for assessment of the hemostatic capacity and it seems a promising tool for evaluation of the individual response to rFVIIa or APCC before and during in vivo administration.

Thrombin causes platelet activation via multiple pathways, and deficient thrombin generation reduces platelet contractile force (PCF) during clot retraction. We hypothesized that PCF in blood samples from clotting factor-deficient patients would be diminished due to delayed or deficient thrombin generation. Blood samples from patients with fibrinogen, and factor V, VII, VIII, IX, X, XI and XIII deficiencies were compared to samples from normal controls. PCF in patient blood clotted with thrombin (1 NIH UmL(-1)) was compared to PCF in clots formed with batroxobin (0.25 micro g mL(-1)). PCF in the former should be normal, but PCF in the latter is dependent on thrombin generation within the sample and might be deficient. In factor VII-(n = 2, P < 0.05), factor VIII-(n = 6, P < 0.005) and factor XI-(n = 2, P < 0.05) deficient platelet-rich plasmas, PCF in batroxobin-induced clots was significantly lower than in thrombin-induced clots. In factor IX deficiency (n = 2), one patient had a dramatic reduction in PCF while a second patient had increased PCF. PCF was insignificantly (P = 0.346) reduced in two patients with factor X deficiency, and was normal in one patient with factor V deficiency. The factor X result is consistent with work in model systems, which indicates that as little as 1-3% factor X activity is sufficient to restore thrombin generation to normal. The factor V result probably indicates that the deficiency is incomplete. PCF in thrombin-induced clots was normal in all of these patients. Low fibrinogen and factor XIII deficiency reduced PCF in both thrombin- and batroxobin-induced clots. These results indicate that PCF is reduced, probably due to delayed thrombin generation, in some factor-deficient platelet-rich plasma samples.