Thrombosis and haemostasis
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Dabigatran is an oral, reversible thrombin inhibitor that has shown promising results in large clinical trials. Laboratory monitoring is not needed but the effects on common coagulation assays are incompletely known. Dabigatran was added to plasma from healthy subjects in the concentration range 0-1,000 μg/l and analysed using several reagents for activated thromboplastin time (APTT), prothrombin time (PT), fibrinogen, antithrombin, and activated protein C resistance. ⋯ The APC-resistance methods over-estimated the APC-ratio, which may lead to miss-classification of factor V Leiden patients as being normal. Different coagulation assays, and even different reagents within an assay group, display variable effects at therapeutic concentrations of dabigatran. Some of these assay variations are of clinical importance, thus knowledge is needed for a correct interpretation of results.
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Randomized Controlled Trial
Does ambulation modify venous thromboembolism risk in acutely ill medical patients?
In the US, ambulatory status is often a criterion for stopping prophylaxis for venous thromboembolism (VTE). In an analysis of the prophylaxis in MEDical patients with ENOXaparin (MEDENOX) trial, ambulatory status was assessed as outcome and patients grouped accordingly for further analysis. Rates of VTE and bleeding were evaluated. ⋯ By multivariate regression analysis, VTE risk in ambulatory patients was lower with enoxaparin vs. placebo (odds ratio [OR] = 0.28; 95% CI, 0.11-0.74; p=0.01), but higher in patients with a history of VTE (OR = 3.74; 95% CI, 1.59-8.84; p=0.003) or cancer (OR = 2.12; 95% CI, 1.00-4.48; p=0.049). Despite timely mobilisation, patients who become ambulatory are at VTE risk and experience a significant risk reduction with enoxaparin 40 mg. Therefore, it is essential that ambulatory patients receive recommended thromboprophylaxis.
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Review Comparative Study
Cost-effectiveness of rivaroxaban versus enoxaparin for the prevention of postsurgical venous thromboembolism in Canada.
This study aimed to evaluate the cost-effectiveness of prophylaxis with rivaroxaban vs. enoxaparin in the prevention of venous thromboembolism (VTE) after total hip replacement (THR) and total knee replacement (TKR) from the perspective of the Canadian healthcare system. A model was developed that included both acute VTE (represented as a decision tree) and long-term complications (represented as a Markov process with one-year cycles). Transition probabilities were derived from phase III clinical trials comparing rivaroxaban with enoxaparin and published literature. ⋯ Similarly, rivaroxaban dominates enoxaparin in patients undergoing TKR, achieving a gain of 0.0018 QALYs, a reduction of 0.0192 symptomatic venous thromboembolic events and savings of C$129 per patient. Rivaroxaban is a cost-effective alternative to enoxaparin for VTE prophylaxis in patients undergoing THR and TKR. Over a five-year horizon, rivaroxaban dominated enoxaparin in the prevention of VTE events in patients undergoing THR and TKR, providing more quality-of-life benefit at a lower cost.
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Randomized Controlled Trial
Oral direct factor Xa inhibition with edoxaban for thromboprophylaxis after elective total hip replacement. A randomised double-blind dose-response study.
Edoxaban is a new oral direct factor Xa inhibitor. The purpose of this study was to evaluate the efficacy and safety of different doses of edoxaban for the prevention of venous thromboembolism (VTE) in patients undergoing elective total hip replacement. A total of 903 patients were randomised to oral edoxaban 15, 30, 60 or 90 mg once daily or subcutaneous dalteparin once daily (initial dose 2,500 IU, subsequent doses 5,000 IU). ⋯ There was a statistically significant (p<0.001) dose-response for efficacy across the edoxaban dose groups for total VTE and for major VTE. The incidence of clinically relevant bleeding was low and similar across the groups. Oral edoxaban once daily is effective for preventing VTE after total hip replacement.