Asian Patients with Stroke plus Atrial Fibrillation and the Dose of Non-Vitamin K Oral Anticoagulants

Abstract

After recent randomized control trials (RCTs), non-vitamin K oral anticoagulants (NAOAs) are now widely being used in patients with atrial fibrillation (AF) worldwide. However, current guidelines for the use of NOACs in patients with AF are derived mostly using a Caucasian population and non-stroke patients. Relatively few Asian patients with AF and stroke are included in the recent RCTs. As a result, the optimal use of NOACs in this particular group of patients is remains to be settled. The optimal dose of NOACs and response to current dose of NOACs of Asian patients with AF and stroke may differ from those of westerners and patients without stroke. We reviewed available research on NOACs by searching PubMed and ClinicalTrials.gov published in English up to December 2015. In this review, the characteristics of Asian AF patients with prior stroke/transient ischemic attack, which might influence the efficacy and safety profiles of NOACs, are discussed. In addition, we summarize the risk factors for bleeding complications on NOACs, which are related or unrelated with the blood level of NOACs. Lastly, we provide recent data of reduced dose of NOACs from RCTs or large cohorts. The results reviewed herein call for clinical trials to test whether a reduced dose of NOACs is beneficial in Asian patients with AF and stroke. In the meantime, further researches are needed to establish the safety and efficacy of dose-adjusted NOACs considering both blood levels of NOACs and fragility of patients in Asian patients with AF and stroke.

Efficacy and Safety of Apixaban, Dabigatran, Rivaroxaban, and Warfarin in Asians With Nonvalvular Atrial Fibrillation

“…Recent real-world practice showed a worldwide trend toward the use of low-dose NOACs. [31][32][33] Because anticoagulation is usually a preventative treatment in AF patients, physicians tend to play it safe by using low-dose NOACs in order to prevent bleeding. Similarly, we observed a high prevalence of low-dose NOAC prescriptions in the present Asian cohort.…”

The East Asian Paradox: An Updated Position Statement on the Challenges to the Current Antithrombotic Strategy in Patients with Cardiovascular Disease

“…2). 30,54 In addition, there is an increasing percentage of AF patients undergoing PCI, where combination therapy of DOAC and antiplatelet therapy is required.…”

Left atrial appendage closure with WATCHMAN in Asian patients: 2 year outcomes from the WASP registry

“…Compared to non-Asians, Asians are at significantly higher risk of warfarin-related intracranial bleeding (HR = 4.06) [2]. Although NOAC trial meta-analysis demonstrated greater proportional reduction compared with warfarin for rates of intracranial haemorrhage for Asian patients versus non-Asians, the absolute rates still remain higher [4,11]. Attention has also been focused on the possible link between macro and micro-angiopathies which are more prevalent in Asian populations and show an increased risk of intracranial haemorrhage [11].…”

“…Although NOAC trial meta-analysis demonstrated greater proportional reduction compared with warfarin for rates of intracranial haemorrhage for Asian patients versus non-Asians, the absolute rates still remain higher [4,11]. Attention has also been focused on the possible link between macro and micro-angiopathies which are more prevalent in Asian populations and show an increased risk of intracranial haemorrhage [11]. Results from a Korean study suggested that among NVAF patients with a recent ischaemic stroke, 17.2% were classified as AF-unrelated, highlighting the complexity surrounding mixed aetiologies of stroke in Asians [12].…”