Defining nonvalvular atrial fibrillation: A quest for clarification

Area of Science:

• Cardiology
• Pharmacology

Background:

• Non-vitamin K oral anticoagulants (NOACs) are recommended for nonvalvular atrial fibrillation (NVAF) based on pivotal trials.
• The definition of NVAF is inconsistent across trials and guidelines, causing clinical uncertainty.
• Many atrial fibrillation patients have valvular involvement, necessitating clear NOAC eligibility criteria.

Purpose of the Study:

• To clarify the definition of nonvalvular atrial fibrillation.
• To define eligibility for NOAC therapy in patients with various forms of valvular heart disease.

Main Methods:

• Review of major pivotal trials for NOACs in atrial fibrillation.
• Analysis of current European Heart Rhythm Association guidelines and position papers.
• Evaluation of patient populations with native, bioprosthetic, and repaired heart valves.

Main Results:

• NOACs are contraindicated only in patients with mechanical heart valves or moderate-to-severe mitral stenosis.
• Patients with native heart valve involvement are suitable for NOACs, irrespective of severity.
• NOACs may be used in patients with bioprosthetic valves or after mitral valve repair/transcatheter procedures, with specific post-operative considerations and careful bleeding risk assessment.

Conclusions:

• Clarification of 'nonvalvular atrial fibrillation' is essential for appropriate NOAC prescription.
• NOACs are suitable for a broader range of atrial fibrillation patients with valvular conditions than previously perceived.
• Further research is needed for NOAC use in specific high-risk groups, such as post-transaortic valve implantation or valvular surgery.