Thrombosis and haemostasis
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Until recently, vitamin K antagonists (VKAs) were the only available oral anticoagulants evaluated for long-term treatment of patients with coronary heart disease (CHD), particularly after an acute coronary syndrome (ACS). Despite efficacy in this setting, VKAs are rarely used because they are cumbersome to administer. Instead, the more readily manageable antiplatelet agents are the mainstay of prevention in ACS patients. ⋯ The role for the NOACs in ACS management, although promising, is therefore complicated, because it is uncertain how they compare with newer antiplatelet agents, such as prasugrel, ticagrelor or vorapaxar, and because their safety in combination with these other drugs is unknown. Ongoing studies are also now evaluating the use of NOACs in non-valvular atrial fibrillation patients, where their role is established, with coexistent ACS or coronary stenting. Focusing on CHD, we review the results of clinical trials with the NOACs and provide a perspective on their future incorporation into clinical practice.
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The prognostic value of the European Society of Cardiology (ESC) 2014 algorithm and the Bova score has lacked adequate validation. According to the ESC 2014 guidelines and the Bova score, we retrospectively risk stratified normotensive patients with PE who were enrolled in the PROTECT study. This study used a complicated course (which consisted of death from any cause, haemodynamic collapse, or recurrent PE) as the primary endpoint, and follow-up occurred through 30 days after the PE diagnosis. ⋯ In conclusion, the ESC 2014 prognostic algorithm is effective in the risk stratification of normotensive patients with PE. Use of CTPA did not improve the ability for identification of low-risk PE. Bova risk scoring did not significantly improve identification of intermediate-high risk PE.
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Zinc released from activated platelets binds fibrin(ogen) and attenuates fibrinolysis. Although zinc also affects clot formation, the mechanism and consequences are poorly understood. To address these gaps, the effect of zinc on clot formation and structure was examined in the absence or presence of factor (F) XIII. ⋯ Whereas FXIII increased clot stiffness from 128 ± 19 Pa to 415 ± 27 Pa in rheological analyses, zinc reduced clot stiffness by 10- and 8.5-fold in the absence and presence of FXIII, respectively. Clots formed in the presence of zinc were more stable and resisted rupture with or without FXIII. Therefore, zinc accelerates clotting and reduces fibrin clot stiffness in a FXIII-independent manner, suggesting that zinc may work in concert with FXIII to modulate clot strength and stability.
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Identifying women at risk of venous thromboembolism (VTE) is a major public health issue. The objective of this study was to identify environmental and genetic determinants of VTE risk in a large sample of women under combined oral contraceptives (COC). A total of 968 women who had had one event of VTE during COC use were compared to 874 women under COC but with no personal history of VTE. ⋯ Family history poorly predicted thrombophilia as its prevalence was similar in patients with or without first degree family history of VTE (29.3% vs 23.9%, p=0.09). In conclusion, this study confirms the influence of smoking and obesity and shows for the first time the impact of ABO blood group on the risk of VTE in women under COC. It also confirms the inaccuracy of the family history of VTE to detect inherited thrombophilia.
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Randomized Controlled Trial Multicenter Study
Extended anticoagulation with apixaban reduces hospitalisations in patients with venous thromboembolism. An analysis of the AMPLIFY-EXT trial.
Treatment with apixaban versus placebo for 12 months significantly reduced symptomatic recurrent venous thromboembolism (VTE) or all-cause death without increasing the rate of major bleeding in the AMPLIFY-EXT trial. This analysis examined the effects of apixaban versus placebo on the rate of all-cause hospitalisations, time to first hospitalisation, and predictors of first hospitalisation in patients with VTE enrolled in AMPLIFY-EXT. Treatment with apixaban 2.5 mg and 5 mg twice daily significantly reduced the rate of all-cause hospitalisations versus placebo (hazard ratio [95% confidence interval], 0.64 [0.43, 0.95]; p=0.026 and 0.54 [0.36, 0.82]; p=0.004, respectively). ⋯ Median length of hospital stay during the first hospitalisation was longer for placebo than for apixaban 2.5 mg or 5 mg twice daily (7.0, 5.0, and 4.5 days, respectively). Treatment with apixaban was a significant predictor of lower rates of hospitalisations versus placebo, and severe/moderate renal impairment was a significant predictor of an increased rate. This study supports extended use of apixaban for reducing all-cause hospitalisations and extending time to first hospitalisation in patients with VTE enrolled in AMPLIFY-EXT (www.clinicaltrials.gov registration: #NCT00633893).