What is the recommended Dual Anti-Platelet Therapy (DAPT) regimen for patients undergoing aortic valve replacement?

Recommended DAPT for Aortic Valve Replacement

For patients with bioprosthetic aortic valves, aspirin 75-100 mg daily alone is recommended for long-term management, while dual antiplatelet therapy with aspirin plus clopidogrel is recommended only for the first 3-6 months after transcatheter aortic valve implantation (TAVI). 1

Antithrombotic Therapy Based on Valve Type

Mechanical Aortic Valve Replacement

• Primary therapy: Vitamin K antagonist (VKA) therapy is mandatory
  • Target INR 2.5 (range 2.0-3.0) for bileaflet or current-generation single-tilting disk mechanical valves without risk factors 1
  • Target INR 3.0 (range 2.5-3.5) for mechanical valves with additional risk factors (AF, previous thromboembolism, LV dysfunction, hypercoagulable state) or older-generation prosthesis 1
• Additional antiplatelet therapy:
  • Addition of low-dose aspirin (75-100 mg daily) to VKA therapy is reasonable for patients at low risk of bleeding 1
  • DOACs are contraindicated with mechanical valves 1

Bioprosthetic Surgical Aortic Valve Replacement (SAVR)

• First 3-6 months:
  • Option 1: Low-dose aspirin (75-100 mg daily) 1
  • Option 2: VKA therapy (target INR 2.5, range 2.0-3.0) for 3-6 months in patients at low risk of bleeding 1
• Long-term therapy (beyond 3-6 months):
  • Aspirin 75-100 mg daily lifelong in the absence of other indications for anticoagulation 1

Transcatheter Aortic Valve Replacement (TAVI)

• First 3-6 months:
  • Dual antiplatelet therapy: Aspirin (75-100 mg daily) plus clopidogrel (75 mg daily) 1
  • For patients at high bleeding risk, single antiplatelet therapy may be considered 1
  • VKA therapy (target INR 2.5) may be reasonable for at least 3 months after valve implantation 1
• Long-term therapy (beyond 3-6 months):
  • Aspirin 75-100 mg daily lifelong in the absence of other indications for anticoagulation 1

Special Considerations

Patients with Existing Indications for Anticoagulation

• For patients with concurrent atrial fibrillation or other indications for long-term anticoagulation:
  • Continue oral anticoagulation lifelong 1
  • Avoid triple therapy (dual antiplatelet plus anticoagulant) when possible due to excessive bleeding risk 1

On-X Mechanical Aortic Valve

• For patients with On-X mechanical aortic valve without thromboembolic risk factors:
  • Lower INR target (1.5-2.0) may be reasonable starting ≥3 months after surgery
  • Continue aspirin 75-100 mg daily 1, 2

Evidence Update

Recent evidence suggests that aspirin alone may be preferable to DAPT after TAVI. A meta-analysis of randomized controlled trials showed that aspirin monotherapy was associated with decreased risk of bleeding without increasing the risk of mortality, stroke, or myocardial infarction compared to DAPT 3. However, current guidelines still recommend DAPT for the initial period after TAVI.

Common Pitfalls to Avoid

1. Inappropriate use of DOACs: Direct oral anticoagulants are contraindicated for mechanical valves and should not be used 1

2. Excessive anticoagulation: Triple therapy (dual antiplatelet plus anticoagulant) significantly increases bleeding risk and should be avoided when possible 1

3. Inadequate monitoring: Regular INR monitoring is essential for patients on VKA therapy, especially during the initial period of anticoagulation

4. Discontinuing antiplatelet therapy prematurely: For bioprosthetic valves, lifelong aspirin therapy is recommended in the absence of contraindications 1

5. One-size-fits-all approach: Bleeding risk assessment is crucial when determining the appropriate antithrombotic regimen, especially when considering combination therapy

By following these evidence-based recommendations, clinicians can optimize the balance between preventing thromboembolism and minimizing bleeding risk in patients with aortic valve replacement.