Anticoagulation for Valvular Atrial Fibrillation

Defining Valvular AF and Anticoagulation Recommendations

The American College of Cardiology recommends warfarin as the only anticoagulant for patients with valvular atrial fibrillation, defined as AF with moderate-to-severe rheumatic mitral stenosis or mechanical prosthetic heart valves, with a target INR of 2.0-3.0 for mitral stenosis and 2.5-3.5 for mechanical valves depending on valve type and position 1
Valvular AF refers exclusively to patients with moderate-to-severe rheumatic mitral stenosis or mechanical prosthetic heart valves, and DOACs are contraindicated in these patients due to lack of safety and efficacy data 1

For patients with rheumatic mitral stenosis and AF, warfarin with a target INR of 2.0-3.0 is mandatory, and DOACs must never be used, even if stenosis is mild 2, 1
For patients with mechanical prosthetic valves and AF, warfarin is the only acceptable anticoagulant, with a target INR depending on valve type and position 2

The American College of Cardiology recommends checking INR at least weekly during warfarin initiation and monthly once stable in therapeutic range 2, 1
The risk of thromboembolism is identical whether AF is paroxysmal, persistent, or permanent, and all patterns require the same anticoagulation intensity 2, 3, 1
The American College of Cardiology advises against using DOACs in patients with any degree of mitral stenosis or mechanical valves, and against underdosing warfarin due to bleeding concerns in high-risk patients 1, 2

For patients requiring cardioversion, the American College of Cardiology recommends maintaining therapeutic anticoagulation for ≥3 weeks before and ≥4 weeks after the procedure 4
Elderly patients (≥75 years) with valvular AF have higher bleeding risk but also higher stroke risk, making anticoagulation particularly beneficial despite age 2, 4
Patients with prior stroke or TIA are at highest risk and derive the greatest benefit from anticoagulation, according to the American College of Cardiology 2, 4