INR Range and Duration of OAC
Recommended therapeutic range and duration by the Committee on Antithrombotic Therapy of the American College of Chest Physicians (ACCP) and the National Heart, Lung, and Blood Institute have been tabulated in the below Tables.
- INR Range75
- Duration of OAC76
Recommended therapeutic range for OAC therapy
Indication | INR |
---|---|
Treatment of venous thrombosis | 2.0–3.0 |
Treatment of pulmonary embolism | 2.0–3.0 |
Prophylaxis of venous thrombosis (high-risk surgery) | 2.0–3.0 |
Prevention of systemic embolism | 2.0–3.0 |
Tissue heart valves | 2.0–3.0 |
AMI (to prevent systemic embolism) | 2.0–3.0 |
Valvular heart disease | 2.0–3.0 |
Atrial fibrillation | 2.0–3.0 |
Bileaflet mechanical valve in aortic position | 2.0–3.0 |
Mechanical prosthetic valves (high-risk) | 2.5–3.5 |
Systemic recurrent emboli | 2.5–3.5 |
AMI, acute myocardial infarction; INR, international normalized ratio; OAC, oral anticoagulant.
Duration of anticoagulation after venous thromboembolism
Type of event or condition | Duration |
---|---|
First event, distal DVT, provoked by temporary risk factors | 6 weeks |
First event, distal DVT with idiopathic or permanent risk factor or any proximal DVT or pulmonary embolism | ≥6 months |
As above with an increased risk of bleeding Single life‐threatening event First event, active cancer |
3 months ≥12 months Until cancer resolved |
Second event, contralateral DVT Second event, ipsilateral main pulmonary thromboembolism |
≥6 months ≥12 months |
Third or subsequent event | Indefinite |
In the ninth edition of evidence-based management of anticoagulant therapy, American College of Chest Physicians (ACCP) recommends that rather than 4-week monitoring, patients with consistently stable INRs can be monitored every 12 weeks.77
DVT, deep vein thrombosis; INR, international normalized ratio; OAC, oral anticoagulant.