What are the alternatives to Warfarin (coumarin) in patients with Rheumatic Heart Disease (RHD) and atrial fibrillation?

Alternatives to Warfarin in Rheumatic Heart Disease with Atrial Fibrillation

Vitamin K antagonists like warfarin remain the only recommended anticoagulants for patients with rheumatic heart disease (RHD) and atrial fibrillation, as direct oral anticoagulants (DOACs) have shown inferior outcomes in this specific population. 1

Evidence Against DOACs in Rheumatic Heart Disease

• The INVICTUS trial demonstrated that vitamin K antagonist therapy led to a lower rate of cardiovascular events and death compared to rivaroxaban in patients with RHD-associated atrial fibrillation, without a higher bleeding rate 1
• Rivaroxaban was associated with a higher incidence of death and worse outcomes compared to vitamin K antagonists in RHD patients with AF 1
• DOACs (dabigatran, rivaroxaban, apixaban) are specifically contraindicated in patients with mechanical heart valves or moderate-to-severe mitral stenosis, which are common in RHD 2

Recommended Anticoagulation in RHD with AF

• Vitamin K antagonists (warfarin) remain the standard therapy for patients with RHD and AF 1
• Target INR should be maintained between 2.0-3.0 with regular monitoring at least weekly during initiation and monthly when stable 2
• For patients unable to take oral anticoagulants, aspirin alone is recommended, though it provides less protection against thromboembolism 3

Anticoagulation Options for Non-Valvular AF (Not Applicable to RHD)

It's important to understand that while DOACs are preferred for non-valvular AF, they are not appropriate for RHD:

• DOACs (dabigatran, rivaroxaban, apixaban) are recommended over warfarin for eligible patients with non-valvular AF due to their superior safety profile 2
• The American College of Cardiology recommends DOACs as first-line therapy for stroke prevention in non-valvular AF 3
• Apixaban has shown lower rates of ischemic stroke, systemic embolism, and bleeding compared to rivaroxaban in patients with non-valvular AF and other types of valvular heart disease (excluding mechanical valves and moderate-to-severe mitral stenosis) 4, 5

Special Considerations

• Renal function should be evaluated before starting any anticoagulant and reassessed at least annually 2
• For patients with end-stage renal disease (CrCl <15 mL/min) with non-valvular AF, warfarin or apixaban might be reasonable options 2, 6
• Apixaban has demonstrated a lower risk of major bleeding compared to warfarin in patients with end-stage renal disease 6

Clinical Algorithm for RHD with AF

1. Confirm diagnosis of RHD with echocardiography
2. Assess stroke risk using CHA₂DS₂-VASc score
3. For patients with RHD and AF:
   • First-line: Vitamin K antagonist (warfarin) with target INR 2.0-3.0 1
   • Monitor INR at least weekly during initiation and monthly when stable 2
   • If unable to tolerate warfarin: Consider aspirin alone (though less effective) 3
4. Do NOT use DOACs (dabigatran, rivaroxaban, apixaban, edoxaban) in RHD with AF 1

Common Pitfalls to Avoid

• Mistakenly using DOACs in patients with RHD, particularly those with mitral stenosis 2
• Inadequate INR monitoring when using warfarin 2
• Failing to recognize that guidelines for non-valvular AF do not apply to RHD patients 3
• Discontinuing anticoagulation without appropriate bridging in high-risk patients 3