What is the target International Normalized Ratio (INR) for a patient with Atrial Fibrillation (AFib), Mitral Regurgitation (MR), and Tricuspid Regurgitation (TR) on warfarin?

Target INR for Patients with Atrial Fibrillation, Mitral Regurgitation, and Tricuspid Regurgitation on Warfarin

For patients with atrial fibrillation (AFib), mitral regurgitation (MR), and tricuspid regurgitation (TR) on warfarin, the target INR should be 2.0-3.0, with an optimal target of 2.5. 1, 2, 3

Rationale for Target INR Range

The recommended INR range is based on extensive evidence showing that:

• INR values below 2.0 significantly increase the risk of thromboembolism and stroke 1, 2
• INR values above 3.0 are associated with increased risk of major bleeding, particularly intracranial hemorrhage when INR exceeds 3.5 1, 4
• The optimal balance between stroke prevention and bleeding risk occurs at an INR of approximately 2.5 2, 4

Specific Considerations for AFib with Valvular Heart Disease

For patients with AFib and valvular heart disease such as mitral regurgitation (MR) and tricuspid regurgitation (TR):

• The standard target INR range of 2.0-3.0 applies, as these valve conditions are considered non-mechanical valvular heart disease 1
• This differs from patients with mechanical heart valves, who may require higher INR targets (2.5-3.5) depending on valve type and position 1, 3
• The presence of MR and TR does not alter the recommended INR target range for AFib patients on warfarin 1, 2

Quality of Anticoagulation Management

To achieve optimal outcomes:

• Time in Therapeutic Range (TTR) should be maintained at ≥65% to maximize efficacy and safety 1, 2
• INR should be monitored at least weekly during initiation of therapy and at least monthly when anticoagulation is stable 1
• If TTR is consistently <65%, additional measures should be implemented:
  • More frequent INR testing
  • Medication adherence review
  • Patient education and counseling
  • Consideration of factors affecting INR control 1, 2, 5

Common Pitfalls to Avoid

1. Targeting too low an INR range: Some clinicians incorrectly target lower INR ranges (1.5-2.0) for elderly patients, which increases stroke risk without clear evidence of reduced bleeding 2, 6

2. Inadequate monitoring: Failure to check INR at appropriate intervals can lead to poor anticoagulation control and adverse outcomes 1, 7

3. Overlooking drug interactions: Many medications interact with warfarin and can significantly affect INR values, requiring dose adjustments 2

4. Ignoring TTR: Focusing only on individual INR values rather than the overall time in therapeutic range can lead to suboptimal management 1, 5

Alternative Approaches

If patients are unable to maintain a therapeutic INR level with warfarin (TTR <65% despite optimization efforts), consider:

• Switching to a direct oral anticoagulant (DOAC) if the patient has non-valvular AFib 1
• For patients with significant valvular disease who cannot maintain therapeutic INR, more frequent monitoring and dose adjustments may be necessary 1, 2

By maintaining the target INR of 2.0-3.0 with good TTR, patients with AFib, MR, and TR can achieve optimal protection against thromboembolic events while minimizing bleeding risk.