INR Goal for Anticoagulation in Atrial Fibrillation

For patients with atrial fibrillation requiring anticoagulation, the target INR range should be 2.0 to 3.0 with a target of 2.5. 1, 2

Standard INR Target Recommendations

For patients with nonvalvular atrial fibrillation at high risk of stroke, oral anticoagulation with a vitamin K antagonist (warfarin) should be adjusted to achieve a target INR of 2.0 to 3.0 (target 2.5) 1
This INR range provides maximum protection against ischemic stroke while minimizing the risk of bleeding complications 1
The same INR target range applies regardless of the pattern of atrial fibrillation (paroxysmal, persistent, or permanent) 1
Atrial flutter should be managed with the same anticoagulation strategy and INR targets as atrial fibrillation 1

For elderly patients (≥75 years) at increased risk of bleeding but without frank contraindications to oral anticoagulant therapy, a lower INR target of 2.0 (range 1.6 to 2.5) may be considered 1, 3
For patients with AF who are on dialysis with a CHA₂DS₂-VASc score of 2 or greater, warfarin with a target INR of 2.0 to 3.0 is recommended 4
For patients with AF who have mechanical heart valves, the target INR should be at least 2.5, with specific targets based on valve type and position 1

INR should be determined at least weekly during initiation of therapy 1, 2
Once anticoagulation is stable, INR monitoring should occur at least monthly 1, 4, 2
Time in therapeutic range (TTR) should ideally be ≥70% to maximize efficacy and safety 1
For patients with consistently low time in therapeutic range (TTR <65%), additional measures should be implemented to improve INR control or switching to NOACs should be considered 1

Multiple randomized clinical trials have demonstrated that an INR range of 2.0 to 3.0 provides the optimal balance between stroke prevention and bleeding risk 1
Lower INR targets (1.5-2.0) have been associated with incomplete efficacy, estimated at approximately 80% of that achieved with higher-intensity anticoagulation 1, 5
A systematic review and meta-analysis found that lower INR targets reduce bleeding but increase thromboembolism in AF patients 5

Low-intensity anticoagulation requires special efforts to minimize time spent below the target range, during which stroke protection is sharply reduced 1, 3
INR variability (as measured by standard deviation of transformed INR) is a stronger predictor of adverse outcomes than time in therapeutic range alone 6
For patients undergoing procedures that carry a risk of bleeding, anticoagulation may be interrupted for up to 1 week without substituting heparin in patients without mechanical heart valves 1
Patients with AF and rheumatic mitral stenosis or mechanical heart valves require anticoagulation with warfarin at appropriate INR targets and are not candidates for NOACs 1

In patients with AF who are eligible for oral anticoagulation, NOACs are now recommended over vitamin K antagonists (VKAs) like warfarin 1
For patients with prior unprovoked bleeding or at high risk of bleeding, specific NOACs (apixaban, edoxaban, or dabigatran 110 mg where available) may be preferable as they demonstrate significantly less major bleeding compared with warfarin 1
Aspirin alone is not recommended for stroke prevention in AF patients, regardless of stroke risk 1