From the Guidelines
Anticoagulation with a vitamin K antagonist (VKA) is recommended for all patients with mechanical aortic valve replacements, with a target INR of 2.5 for patients with a mechanical bileaflet or current-generation single-tilting disk AVR and no risk factors for thromboembolism, and an INR of 3.0 for patients with additional risk factors for thromboembolism or an older-generation prosthesis. The indications for anticoagulation in patients with mechanical aortic valve (AV) replacement are based on the type of valve and the presence of risk factors for thromboembolism. According to the 2020 ACC/AHA guideline for the management of patients with valvular heart disease 1, anticoagulation with a VKA is recommended for all patients with mechanical prosthetic valves.
The target INR for anticoagulation varies depending on the type of valve and the presence of risk factors for thromboembolism. For patients with a mechanical bileaflet or current-generation single-tilting disk AVR and no risk factors for thromboembolism, an INR of 2.5 is recommended 1. For patients with additional risk factors for thromboembolism, such as atrial fibrillation, previous thromboembolism, left ventricular dysfunction, or a hypercoagulable state, or an older-generation prosthesis, an INR of 3.0 is recommended 1.
Some key points to consider when managing anticoagulation in patients with mechanical aortic valve replacements include:
- The use of low-dose aspirin (75-100 mg daily) in addition to VKA for additional protection 1
- The contraindication of direct oral anticoagulants (DOACs) like apixaban and rivaroxaban in mechanical valves 1
- The importance of regular INR monitoring, typically every 2-4 weeks once stable, with more frequent checks during medication changes or illness
- The need for patient education about bleeding risks, medication interactions, and the importance of consistent vitamin K intake through diet.
Overall, the goal of anticoagulation in patients with mechanical aortic valve replacements is to prevent valve thrombosis and systemic embolism, particularly stroke, while minimizing the risk of bleeding complications.
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 indications for anticoagulation in patients with mechanical aortic valve (AV) replacement are:
- All patients with mechanical prosthetic heart valves, including those with a mechanical aortic valve replacement, should receive warfarin.
- A target INR of 2.5 (range, 2.0 to 3.0) is recommended for patients with a mechanical aortic valve replacement, such as a St. Jude Medical bileaflet valve in the aortic position 2.
From the Research
Indications for Anticoagulation in Patients with Mechanical Aortic Valve Replacement
The indications for anticoagulation in patients with mechanical aortic valve (AV) replacement are based on the risk of thromboembolism and valve thrombosis. Key points to consider include:
- The use of vitamin-K-antagonists (VKA) such as warfarin is currently recommended for anticoagulation in patients with mechanical aortic valve replacement 3
- The target international normalized ratio (INR) for patients with mechanical aortic valve replacement is typically between 2.0 and 3.0, but some studies suggest that a lower INR target of 1.8 (range 1.5-2.0) may be safe and effective in certain patients 4
- Patients with additional risk factors for thromboembolism, such as atrial fibrillation, may require higher intensity anticoagulation, but the optimal INR target for these patients is not well established 5
Alternative Anticoagulation Therapies
Alternative anticoagulation therapies, such as direct oral anticoagulants (DOACs), are being investigated for use in patients with mechanical aortic valve replacement. Key points to consider include:
- DOACs, such as apixaban and rivaroxaban, have shown promising results in smaller studies and case reports, but larger trials are needed to establish their safety and efficacy 3
- The use of DOACs may offer advantages over VKA therapy, including reduced risk of bleeding and improved quality of life 3
Management of Bleeding Complications
Bleeding complications are a significant concern in patients with mechanical aortic valve replacement who are receiving anticoagulation therapy. Key points to consider include:
- The management of major bleeding episodes, such as intracranial hemorrhage or gastrointestinal bleeding, typically involves reversing warfarin-induced coagulopathy with vitamin K supplementation, fresh frozen plasma, or prothrombin complex concentrate (PCC) 6
- The safe resumption of anticoagulation after a bleeding episode is not well established, and guidelines are limited to case reports and series 6