Oral anticoagulants for Asian patients with atrial fibrillation
Nature Reviews Cardiology (Impact Factor: 9.18). 03/2014; 11(12). DOI: 10.1038/nrcardio.2014.22
Anticoagulation is the most-important intervention to prevent stroke in patients with atrial fibrillation (AF). Despite a lower point prevalence of AF in Asian communities and Asian countries than in other populations, individuals of Asian ethnicity are at a disproportionately high risk of stroke and have greater consequent mortality. Warfarin and other vitamin K antagonists are conventionally used for anticoagulation, and demonstrably reduce the risk of stroke and all-cause mortality in patients with AF. The use of warfarin in Asian countries is suboptimal, primarily owing to the universal challenge of achieving controlled anticoagulation with an unpredictable drug as well as concerns about the particularly high-risk of haemorrhage in Asian patients. Instead, antiplatelet therapy has been favoured in Asian communities, this strategy is neither safe nor effective for stroke prevention in these individuals. The non-vitamin K antagonist, oral anticoagulant drugs offer a solution to this challenge. The direct thrombin inhibitor dabigatran, and the direct factor Xa inhibitors apixaban, edoxaban, and rivaroxaban, have demonstrated noninferiority to warfarin in the prevention of stroke and systemic embolism in international, randomized, controlled trials. Importantly, some of these drugs are also associated with a significantly lower incidence of major haemorrhage, and all result in lower rates of intracranial haemorrhage and haemorrhagic stroke than warfarin. In this article, we review the use of the non-vitamin K antagonist anticoagulants in the management of AF in Asian populations.
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- "Moreover, warfarin, a vitamin K antagonist, also has been demonstrated to accelerate the calcification process of the arterial wall  and possibly increase the rate of ischemic events  . It remains unclear whether patients with ESRD should be aggressively anti-coagulated to prevent ischemic stroke in general population especially in Asians who bear higher incidence of hemorrhage, labile INR and less thrombosis events as compared with western people   . "
ABSTRACT: The risk/benefit profiles of anti-coagulant or anti-platelet agents in patients with end-stage renal disease (ESRD) and atrial fibrillation (AF) remained unclear. We aimed to investigate the stroke risks in these patients with or without anti-coagulant/anti-platelet therapy by using our national database. By using our national health insurance ESRD claim database, we searched patients with AF, more than 18years old and without prior history of ischemic stroke. Medication information as well as the events of ischemic stroke, hemorrhagic stroke, and transient ischemic accident during follow-up were identified from the database. Propensity score method was used to match all the potential confounders between patients with and without anti-platelets/warfarin treatment. A total of 134,410 ESRD patients were identified in the database. Among them, patients with non-valvular AF, over 18years old, without prior history of ischemic stroke and received monotherapy with anti-platelets (1622) or warfarin (294) served as case groups while patients (2983) without taking any anti-platelets and warfarin served as control groups. The incidences of ischemic stroke or transient ischemic attack (TIA) were not different among the control (6.6%), anti-platelet (6.2%) and warfarin (5.1%) groups in a follow-up period of approximately 4years. The results remained unchanged after propensity match. Cox-regression analyses also showed no beneficial effect of anti-platelet or warfarin therapy in overall and any subgroups. In this nationwide cohort analyses, we found that anti-platelet or warfarin treatment could not lower the risk of ischemic stroke in patients with ESRD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
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ABSTRACT: Background: We conducted a multicenter retrospective cohort study to elucidate the characteristics of intracranial hemorrhage (ICH) in patients with atrial fibrillation treated with non-vitamin K antagonist oral anticoagulants (NOACs). Method and results: We sent a questionnaire to the directors of 241 stroke centers in Japan to establish the clinical characteristics of NOAC-associated cerebral hemorrhage (CH), including hematoma size, hematoma enlargement (HE) and in-hospital mortality of patients treated in their institutions. We undertook a literature review to establish the clinical characteristics of warfarin-associated CH and compared these with our data. We received 174 responses (72.2%), of which 67 (38.5%) gave anonymous details of 130 eligible patients (male, 67.7%; mean age, 77.3±8.3 years, in-hospital mortality rate, 11.5%). We judged that 87 of the 130 patients had presented with CH: one-fifth had taken antiplatelet drugs. We found that the incidences of HE and mortality in the 87 patients presenting with NOAC-associated CH were lower than would have been expected in those with warfarin-associated CH (17% vs. 26%, and 16% vs. 35%, respectively). Conclusions: More than half the stroke center directors who responded to our questionnaire had not experienced cases of NOAC-associated ICH. Compared with warfarin, NOACs appear to present a lower risk of HE and death in patients with atrial fibrillation who develop CH.
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ABSTRACT: Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and is a growing health problem that is associated with a significantly increased risk of stroke and thromboembolism. Oral anticoagulant (OAC) therapy reduces the risk of stroke and all-cause mortality in patients with AF. OAC therapy is commonly given as a well-controlled vitamin K antagonist (VKA; e.g. warfarin) and can reduce the risk of stroke in AF patients by almost two-thirds. However the widespread use of VKAs has been hampered by the unpredictable pharmacokinetic and pharmacodynamic properties of the drugs and justifiable concerns about the consequent risk of haemorrhage. The non-VKA OACs (NOACs) have revolutionised thromboprophylaxis in AF by providing therapeutic options with predictable pharmacodynamic and pharmacokinetic properties that are as efficacious as warfarin in the prevention of stroke and thromboembolism but are more convenient to use. In this review, we provide a patient-centred framework to assist clinicians in recommending the right OAC therapy to fit the individual patient with AF, including methods for stratifying the risk of stroke and haemorrhage and the chances of achieving tight control of VKA anticoagulation, and we discuss the properties of the NOACs that favour their use in particular patient cohorts. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.