From the Guidelines
For patients with a metallic aortic valve, the target INR range should be 2.0-3.0, with a goal of 2.5, as this provides a reasonable balance between the risks of thromboembolism and bleeding. This recommendation is based on the 2020 ACC/AHA guideline for the management of patients with valvular heart disease 1. The guideline suggests that for current-generation mechanical valve prostheses in the aortic position, an INR of 2.5 (range, 2.0–3.0) is appropriate.
Key Considerations
- The INR target range may need to be adjusted based on individual patient risk factors, such as atrial fibrillation, previous thromboembolism, or hypercoagulable conditions, which may require a higher target INR of 3.0 (range, 2.5–3.5) 1.
- Regular INR monitoring is crucial to maintain the target range and minimize the risk of complications.
- Patients should be educated on the importance of consistent vitamin K intake and the need to carry medical identification indicating their mechanical valve and anticoagulation therapy.
Rationale
The recommended INR target range is based on studies demonstrating that moderate-intensity anticoagulation (INR 2.0-3.0) is effective in reducing the risk of thromboembolic events while minimizing the risk of bleeding complications in patients with metallic aortic valves 1. A randomized trial comparing moderate-intensity with high-intensity oral anticoagulation in patients with a single mechanical valve replacement found no difference in embolic events but a reduction in bleeding with the moderate-intensity group 1.
Patient Management
- Patients with a metallic aortic valve should be closely monitored for signs of thromboembolism or bleeding complications.
- INR levels should be checked regularly, initially weekly, then monthly once the target range is consistently achieved.
- Patients should be educated on the importance of adhering to their anticoagulation regimen and maintaining a consistent diet to minimize INR fluctuations.
From the FDA Drug Label
For all patients with mechanical prosthetic heart valves, warfarin is recommended. For patients with a St. Jude Medical (St. Paul, MN) bileaflet valve in the aortic position, a target INR of 2.5 (range, 2.0 to 3. 0) is recommended.
The target INR for a patient with a metallic aortic valve is 2.5 (range, 2.0 to 3.0) 2.
From the Research
INR Target for Metallic Aortic Valve
The International Normalized Ratio (INR) target for patients with a metallic aortic valve varies depending on the type of valve and the patient's risk factors for thromboembolism.
- For patients with a bileaflet mechanical aortic valve, the recommended INR target is 2-3 3, 4.
- For patients with a mechanical aortic valve and additional risk factors for thromboembolism, the recommended INR target is 2.5-3.5 3, 5, 4.
- However, some studies suggest that a lower INR target of 1.5-2.5 may be safe and effective for patients with an On-X aortic mechanical valve, especially when combined with low-dose aspirin 4, 6.
- Another study found that an INR target of 1.5-2.5 was non-inferior to a standard INR target of 2.0-3.0 in terms of thromboembolic events, and resulted in a significant reduction in bleeding events 7.
Specific Valve Types
- For On-X aortic valve recipients, an INR goal of 1.5-2.5 with low-dose aspirin may be considered, especially 3 months after valve implantation 4, 6.
- For bileaflet mechanical aortic valve recipients, an INR goal of 2-3 for low-risk patients and 2.5-3.5 for high-risk patients may be considered 4.