For decades, warfarin has remained the standard oral anticoagulation for stroke prevention in atrial fibrillation (AF). Three novel oral anticoagulants (NOACs) have been recently approved for stroke prevention in non-valvular AF: dabigatran, rivaroxaban and apixaban. Better pharmacological and clinical profiles make these newcomers a preferable alternative over warfarin. Current AF guidelines do not endorse NOACs over warfarin, or one NOAC over another. Indeed, choice of the anticoagulation regimen should be personalized based on the relative efficacy and safety of different agents across subgroups stratified by thrombotic and bleeding risk, as well as on other clinical factors, including anticoagulation control on warfarin, drug interactions, compliance and need for coagulation monitoring. This review appraises i) the randomized evidence on approved NOACs versus warfarin in AF across subgroups stratified by risk factors of stroke and bleeding and by the anticoagulation level reached on warfarin; and ii) clinical factors impacting on the anticoagulation regimen selection. 相似文献
After a gap of almost 60 years following the development of warfarin, 2 new categories of oral anticoagulant agents have been approved for clinical use - the direct thrombin inhibitors and factor Xa inhibitors. These agents promise to be more convenient to administer with fixed dosing but still have equivalent efficacy and improved bleeding risk compared to warfarin. The clinical community is looking forward to the widespread usage of these agents but there is also some apprehension regarding bleeding risks, non-availability of specific reversal strategies and lack of specific monitoring parameters. This review article will attempt to educate the reader about three representative drugs from these classes: Dabigatran, Rivaroxaban and Apixaban. We will discuss the historical perspective to the development of these drugs, available research data and pharmacology of these agents. The best strategies for monitoring and reversal of these drugs in special situations will also be touched upon. 相似文献
BackgroundDirect oral anticoagulants (DOACs) have promised superior efficacy to low molecular weight heparins in the prevention of venous thromboembolism (VTE) in total hip and knee arthroplasty. However, there are concerns about raised associated bleeding and wound problems with these agents. This study aims to evaluate and compare the efficacy and safety of the 3 DOAC drugs: rivaroxaban, dabigatran and apixaban.MethodsThe primary outcome measures were rate of symptomatic VTE and major bleeding. Secondary outcome measures were wound healing problems and requirement for return to theater. A total of 2431 patients received one of the DOAC drugs as thromboprophylaxis following total hip arthroplasty (35 days) or total knee arthroplasty (14 days) between 2011 and 2015. Binary variables were compared between the 3 groups by using the chi-squared test or Fisher’s exact test. Relative risks of selected primary and secondary end points were also calculated for the prespecified pairwise comparison.ResultsThe overall symptomatic VTE rate was 2%. Rivaroxaban had a statistically significant superior efficacy for overall VTE prevention (0.8% vs 2.6%) compared with dabigatran (P < .01) and apixaban (P < .01), and deep vein thrombosis prevention (0.3% vs 2.2%) over dabigatran (P < .01). The overall rate of major bleeding was 1.2% with no significant difference observed between the 3 studied drugs.ConclusionAll 3 drugs had symptomatic VTE rates comparable with low molecular weight heparin from the published literature. Rivaroxaban appears to have superior efficacy in VTE prevention over apixaban and dabigatran. No statistical difference was observed for major bleeding with any of the 3 agents. 相似文献
Summary. Background: Apixaban is an oral, direct factor Xa (FXa) inhibitor in late-stage clinical development. This study assessed effects of the direct FXa inhibitors, apixaban and rivaroxaban, vs. the direct thrombin inhibitor, dabigatran, on venous thrombosis (VT), bleeding time (BT) and clotting times in rabbits. Methods: We induced the formation of non-occlusive thrombus in VT models by placing threads in the vena cava, and induced bleeding by the incision of cuticles in anesthetized rabbits. Apixaban, rivaroxaban and dabigatran were infused IV to achieve a stable plasma level. Clotting times, including the activated partial thromboplastin time (aPTT), prothrombin time (PT), modified PT (mPT) and thrombin time (TT), were measured. Results: Apixaban, rivaroxaban and dabigatran exhibited dose-related efficacy in preventing VT with EC50 of 65, 33 and 194 n m , respectively. At doses for 80% reduction of control thrombus, apixaban, rivaroxaban and dabigatran prolonged BT by 1.13 ± 0.02-, 1.9 ± 0.1-* and 4.4 ± 0.4-fold*, respectively (* P < 0.05, vs. apixaban). In the treatment model, these inhibitors equally prevented growth of a preformed thrombus. Antithrombotic doses of apixaban and rivaroxaban prolonged aPTT and PT by <3-fold with no effect on TT. Dabigatran was ≥50-fold more potent in prolonging TT than aPTT and PT. Of the clotting assays studied, apixaban, rivaroxaban and dabigatran responded the best to mPT. Conclusion: Comparable antithrombotic efficacy was observed between apixaban, rivaroxaban and dabigatran in the prevention and treatment of VT in rabbits. Apixaban and rivaroxaban exhibited lower BT compared with dabigatran at equivalent antithrombotic doses. The clinical significance of these findings remains to be determined. 相似文献
Introduction: Patients with atrial fibrillation have an increased risk for stroke, systemic embolism and cardiovascular events, including myocardial infarction and cardiovascular death. However, the majority of studies that have analyzed the efficacy of anticoagulants have been focused only on their effects on the risk of stroke.
Areas covered: The available evidence about the association between atrial fibrillation and cardiovascular disease as well as the effects of oral anticoagulation on cardiovascular death and myocardial infarction, with a particular focus on direct oral anticoagulants, was updated in this review.
Expert opinion: The management of patients with atrial fibrillation should not be limited to the prevention of stroke, but should also include the prevention of cardiovascular events. Despite treatment with vitamin K antagonists, many patients with atrial fibrillation still develop cardiovascular complications, particularly individuals whose anticoagulation is difficult to control. Direct oral anticoagulants overcome the majority of limitations of vitamin K antagonists and compared with warfarin, they lead to a greater reduction in the risk of stroke or systemic embolism, all-cause mortality, and intracranial hemorrhage. Although these drugs can only be compared indirectly, it seems that not all direct oral anticoagulants are equal with regard to the prevention of myocardial infarction. 相似文献