Antithrombotic therapy for stroke prevention in patients with atrial fibrillation in Japan

ABSTRACT

Introduction

Stroke remains one of the major public health problems in Japan. The number of patients with atrial fibrillation (AF) has been steadily increasing with the aging of the Japanese population. Appropriate oral antithrombotic therapy is necessary to prevent AF-related stroke and bleeding complications.

Areas covered

The authors summarize the Japanese guidelines for antithrombotic therapy, as well as the current status of antithrombotic therapy, and future perspectives for antithrombotic therapy for patients with AF in Japan.

Expert opinion

Further improvement in adherence to guideline-recommended warfarin therapy may be difficult to achieve. After the introduction of direct oral anticoagulants (DOACs) into clinical practice, the proportion of patients with AF receiving oral anticoagulant therapy has increased in Japan. However, the proportion of patients treated with inappropriately reduced doses of DOACs has also been increasing. Inappropriate dose reduction of DOACs simply because of advanced age should be avoided to reduce stroke events in patients with AF. Among patients with AF receiving anticoagulant therapy who have coronary artery disease, inappropriately prolonged triple therapy or dual therapy should be avoided to reduce major bleeding complications. Shortening the duration of triple therapy or dual therapy may be promoted by simplified recommendations in the 2020-updated guidelines supported by solid evidence.

KEYWORDS:

• Atrial fibrillation
• stroke
• antithrombotic therapy
• warfarin
• direct oral anticoagulants

Article highlights

• The number of patients with atrial fibrillation (AF) has been increasing with the aging of the Japanese population, potentially leading to a further increase in the number of cardioembolic strokes in Japan.

• The recently updated 2020 Japanese Circulation Society (JCS) guidelines recommend that direct oral anticoagulants (DOACs) should be considered, whenever indicated, as the first-line therapy for stroke prevention in patients who have non-valvular AF with a CHADS₂ score ≥1, whereas warfarin therapy with a PT-INR 1.6-2.6 may be considered but is not strongly recommended when DOACs are not contraindicated in patients with non-valvular AF.

• Although the prescription rate of DOACs has been increasing in Japan, a community-based prospective survey showed that there is no significant difference between patients with AF receiving DOAC therapy and patients with AF receiving warfarin therapy with regard to the incidence rates of thromboembolic or major bleeding events, which may be due, in part, to inappropriate reductions of DOAC dose and poor adherence to DOAC therapy.

• Shortening the duration of triple therapy or dual therapy in patients receiving anticoagulant therapy with coronary artery disease may be promoted by an evidence-based simplified antithrombotic regimen without the need for initial assessment of bleeding risk in Japan.

• Considering the higher bleeding risk in the Japanese population than that in other populations, the number of mechanical LAA closure procedures may increase in the future in Japan.

• This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

The authors are supported by Grant-in-Aids for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan (Grant No. 18590815 and 21590898) and a Grant in Aid from the Japanese Arteriosclerosis Prevention Fund.