Background: Venous thromboembolism (VTE) is the third most common vascular disease. Medical inpatients, long-term care residents, persons with minor injuries, and long-distance travelers are at increased risk. Objective: These evidence-based guidelines from the American Society of Hematology (ASH) intend to support patients, clinicians, and others in decisions about preventing VTE in these groups. Methods: ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline-development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and adult patients. The Grading of Recommendations Assessment, Development and Evaluation approach was used to assess evidence and make recommendations, which were subject to public comment. Results: The panel agreed on 19 recommendations for acutely ill and critically ill medical inpatients, people in long-term care facilities, outpatients with minor injuries, and long-distance travelers. Conclusions: Strong recommendations included provision of pharmacological VTE prophylaxis in acutely or critically ill inpatients at acceptable bleeding risk, use of mechanical prophylaxis when bleeding risk is unacceptable, against the use of direct oral anticoagulants during hospitalization, and against extending pharmacological prophylaxis after hospital discharge. Conditional recommendations included not to use VTE prophylaxis routinely in long-term care patients or outpatients with minor VTE risk factors. The panel conditionally recommended use of graduated compression stockings or low-molecular-weight heparin in long-distance travelers only if they are at high risk for VTE.

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Odds ratios and their 95% confidence intervals (95% CI) were cal- open-access paper. doi:10.3324/haematol.2013 Recent studies suggest that leukocytes and erythrocytes play a role in coagulation. However, whether leukocytes, erythrocytes and other hematologic variables are associated with risk of venous thrombosis is not well known. To study this, we used data from 2473 patients with venous thrombosis and 2935 controls. The variables assessed were: total leukocytes, granulocytes, lymphocytes, monocytes, hematocrit, hemoglobin, erythrocytes and red cell indices (mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and red cell distribution width). We found a strong dose-response relation for higher red cell distribution width and monocyte count with risk of venous thrombosis, with odds ratios of 3.1 (95% confidence interval, 2.0-4.8) and 2.8 (95% confidence interval, 1.3-5.8), respectively, after adjustment for age, sex, C-reactive protein level, malignancy and co-morbidities. Monocyte count and red cell distribution width were associated with venous thrombosis even within reference ranges. A low monocyte count (<0.12x10 9 /L) was associated with a lower risk of venous thrombosis after full adjustment (odds ratios 0.6; 95% confidence interval, 0.4-0.8). In summary, high red cell distribution width and blood monocyte count, two parameters that are inexpensive and easily obtainable, were clearly associated with an increased risk of venous thrombosis. Future studies should evaluate the underlying mechanism and the use of these variables in prediction models for first and recurrent thrombosis. ©2013 Ferrata Storti Foundation. This is an Hematologic variables and venous thrombosis: red cell distribution width and blood monocyte count are associated with an increased risk

Key Points• The protein S SHBG-like domain and, more specifically, its LG1 subunit are important for binding and enhancement of TFPI.• TFPI binding to the protein S SHBG-like domain likely positions TFPI Kunitz domain 2 for optimal interaction with the active site of FXa.Protein S is a cofactor for tissue factor pathway inhibitor (TFPI), accelerating the inhibition of activated factor X (FXa). TFPI Kunitz domain 3 residue Glu226 is essential for enhancement of TFPI by protein S. To investigate the complementary functional interaction site on protein S, we screened 44 protein S point, composite or domain swap variants spanning the whole protein S molecule for their TFPI cofactor function using a thrombin generation assay. Of these variants, two protein S/growth arrestspecific 6 chimeras, with either the whole sex hormone-binding globulin (SHBG)-like domain (Val243-Ser635; chimera III) or the SHBG laminin G-type 1 subunit (Ser283-Val459; chimera I), respectively, substituted by the corresponding domain in growth arrest-specific 6, were unable to enhance TFPI. The importance of the protein S SHBG-like domain (and its laminin G-type 1 subunit) for binding and enhancement of TFPI was confirmed in FXa inhibition assays and using surface plasmon resonance. In addition, protein S bound to C4b binding protein showed greatly reduced enhancement of TFPI-mediated inhibition of FXa compared with free protein S. We show that binding of TFPI to the protein S SHBG-like domain enables TFPI to interact optimally with FXa on a phospholipid membrane. (Blood. 2014;123(25):3979-3987) IntroductionTissue factor pathway inhibitor (TFPI) is a ;41 kDa Kunitz-type protease inhibitor that consists of an acidic amino-terminal polypeptide, followed by 3 tandem Kunitz-type domains (Kunitz domains 1, 2, and 3) and a basic carboxy (C)-terminal tail. 1 It circulates in plasma at a concentration of ;1.6 nM. 2,3 The majority (;80%) of plasma TFPI is truncated and bound to lipoproteins, ;5% is localized in storage granules within platelets, ;5% circulates as free truncated variants, and only around 10% is considered to be free full-length TFPI, 4 with this having the greatest anticoagulant activity. [5][6][7] TFPI and its cofactor protein S downregulate tissue factor (TF)-induced thrombin generation, and a deficiency of either protein has been linked to an increased risk of venous thrombosis. [8][9][10] TFPI specifically inhibits the initiation of coagulation through direct binding and inhibition of factor Xa (FXa) and, in a FXa-dependent manner, inhibition of the TF/factor VIIa (FVIIa) complex by forming a quarternary TF/FVIIa/FXa/TFPI complex. 11,12 The P1 residue in the Kunitz domain 2 of TFPI is required for binding to FXa, whereas the P1 residue in Kunitz domain 1 is required for binding and inhibition of TF/FVIIa. 13 The kinetic mechanism of FXa inhibition by TFPI is described as a 2-step process where TFPI first forms an immediate encounter complex with FXa (FXa/TFPI), followed by a slow isomerization into a final tight complex (FXa/TFPI*...

Introduction Brazil has the fourth largest world population of patients with haemophilia. However, mortality rates in this population are unknown. Aim To analyse mortality and its causes in Brazilian patients with haemophilia from 2000 to 2014. Methods The number of deceased patients with haemophilia and causes of death were obtained from the Brazilian National Mortality Information System (SIM), according to the 10th International Classification of Diseases (ICD‐10). Standardized mortality ratios (SMR) were calculated to estimate the rate of overall death of patients with haemophilia relative to that of the Brazilian general male population. Results A total of 784 deaths were identified in the period of 15 years. Mortality of patients with haemophilia was 13% higher when compared with the general male population (SMR 1.13, 95% CI: 1.01‐1.16). Haemorrhage was the main cause of death (n = 254; 32.4%) of which 137 (54%) was intracranial haemorrhage. The total number of deaths due to HIV decreased over the years, and an increase in deaths due to cancer and cardiovascular disease was observed. A total of 129 deaths (16.5%) were related to hepatitis infection, of whom, 109 (86.5%) patients also presented with cirrhosis and hepatocellular carcinoma or other liver diseases. Conclusion Mortality rate of Brazilian patients with haemophilia decreased over the evaluated period. Intracranial haemorrhage is still an important cause of death in these patients, which requires major effort for prevention. Death due to age‐related cardiovascular disease and cancer has increased over the years, following the same tendency observed in developed countries.

Protein S has an established role in the protein C anticoagulant pathway, where it enhances the factor Va (FVa) and factor VIIIa (FVIIIa) inactivating property of activated protein C (APC). Despite its physiological role and clinical importance, the molecular basis of its action is not fully understood. To clarify the mechanism of the protein S interaction with APC, we have constructed and expressed a library of composite or point variants of human protein S, with residue substitutions introduced into the Gla, thrombin-sensitive region (TSR), epidermal growth factor 1 (EGF1), and EGF2 domains. Cofactor activity for APC was evaluated by calibrated automated thrombography (CAT) using protein S-deficient plasma. Of 27 variants tested initially, only one, protein S D95A (within the EGF1 domain), was largely devoid of functional APC cofactor activity. Protein S D95A was, however, ␥-carboxylated and bound phospholipids with an apparent dissociation constant (Kd app ) similar to that of wildtype (WT) protein S. In a purified assay using FVa R506Q/R679Q, purified protein S D95A was shown to have greatly reduced ability to enhance APC-induced cleavage of FVa Arg306. It is concluded that residue Asp95 within EGF1 is critical for APC cofactor function of protein S and could define a principal functional interaction site for APC. (Blood. 2010;115(23): 4878-4885) IntroductionProtein S, a vitamin K-dependent plasma anticoagulant protein, functions as an enhancing cofactor to activated protein C (APC) in the inactivation of activated factors V (FVa) and VIII (FVIIIa). 1 Protein S also has an APC-independent activity that has recently been attributed to its ability to enhance tissue factor pathway inhibitor (TFPI). 2,3 Protein S has an important role in vivo, as is shown clinically by infants with complete deficiency, who suffer purpura fulminans, and by heterozygous carriers of PROS1 gene deletions and point mutations, who are at enhanced risk of venous thromboembolism. 4,5 The importance of protein S has also been demonstrated in murine knockouts, which fail to survive development. 6,7 Protein S binds phospholipids and helps to localize APC to the membrane surface, in proximity to FVa and FVIIIa. In doing so, rather than the preferential cleavage at Arg506 of FVa by APC, Arg306 is then favored, with cleavage enhanced approximately 20-fold. 8 Although this effect has generally been accepted to be due to protein S repositioning of the active site of APC, 9 this has recently been questioned. 10 Cleavage at Arg506 and Arg306 fully inactivates FVa, thereby efficiently down-regulating coagulation. 11 APC also inactivates FVIIIa by cleaving first at Arg336 and thereafter at Arg562. In the presence of protein S, it has been shown that the efficiency of cleavage after Arg336 by APC is enhanced approximately 3-fold. 12 Protein S is a 635-amino acid glycoprotein, circulating at a plasma concentration of approximately 350nM. It is composed of an N-terminal Gla domain (amino acids 1-45), a thrombinsensitive region (TSR; amino acids 46-75)...

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Inherited coagulopathies are bleeding disorders, which require treatment for life. Keeping an updated registry on these diseases is crucial for planning care, documenting prevalence of diseases and evaluating effectiveness of resources. We have analysed data from 26 treatment centres on coagulopathies in Brazil. Information included socio-demographic data, diagnosis of coagulopathies, severity of haemophilias A and B, presence and quantification of inhibitors in haemophilia, type of von Willebrand disease (VWD) and infection status for viral diseases. On 1 July 2007, there were 10 982 patients with inherited coagulopathies in Brazil, of which 6881 (62.7%) corresponded to haemophilia A, 1291 (11.7%) to haemophilia B, 2333 (21.2%) to VWD, 258 (2.4%) to other coagulopathies and 219 (2.0%) to undiagnosed bleeding disorders. Haemophilia A and B inhibitors were present in 9.9% and 1.9% of the patients, respectively. Human immunodeficiency virus infection was present is 6.5%, 4.8% and 1% of patients with haemophilia A, B and VWD, respectively. Hepatitis C virus infection was present in 34.9%, 29.7% and 12% of patients with haemophilia A, B and VWD, respectively. Infection by hepatitis B and human T-cell leukemia-lymphoma virus was also reported. This is the first report on the registry of patients with inherited coagulopathies in Brazil, supposed to be the third largest population of patients with haemophilia.