Antithrombotic Therapy After TAVR
Dual antiplatelet therapy with clopidogrel 75 mg daily for the first 6 months plus lifelong aspirin 75-100 mg daily is recommended after TAVR for patients without indications for anticoagulation. 1
Standard Antithrombotic Regimen for TAVR Patients
- For patients without indications for anticoagulation, the recommended regimen is clopidogrel 75 mg daily for 3-6 months plus lifelong aspirin 75-100 mg daily 1, 2
- This recommendation is based on protocols used in prospective randomized controlled trials of balloon-expandable TAVR, though the specific issue of antiplatelet therapy was not directly assessed in these trials 1
- The metallic expandable frame of the TAVR valve poses a thrombotic risk until the prosthesis becomes fully endothelialized 1
Special Considerations for Different Patient Groups
Patients with Atrial Fibrillation or Other Indications for Anticoagulation
- For patients with chronic atrial fibrillation or other indications for long-term anticoagulation, oral anticoagulation should be prescribed according to guidelines for atrial fibrillation in patients with prosthetic heart valves 1, 2
- Oral anticoagulation alone may be preferable to combination therapy with antiplatelet agents in these patients, as the combination significantly increases bleeding risk without reducing stroke risk 3, 4
- Pre-existing atrial fibrillation is present in approximately 25% of patients undergoing TAVR, and new-onset atrial fibrillation after TAVR occurs in 0.6% to 8.6% of patients 1
Valve Thrombosis Considerations
- Subclinical leaflet thrombus formation may be more common after valve replacement than previously appreciated 1
- Vitamin K antagonist therapy may be considered in the first 3 months after TAVR in patients at risk of valve thrombosis, depending on the specific risk-benefit ratio 1
- Anticoagulation with a vitamin K antagonist (VKA) to achieve an INR of 2.5 may be reasonable for at least 3 months after TAVR in patients at low risk of bleeding 1
- In observational studies, antiplatelet therapy has little effect on bioprosthetic valve thrombosis, whereas anticoagulation is effective in both prevention and treatment of thrombosis 5
Monitoring and Follow-up
- Patients should be followed closely by the implanting physician team for the first 30 days after TAVR to diagnose and follow any procedural complications 1
- Evaluations should include a post-TAVR baseline echocardiogram and ECG to document any conduction abnormalities 1
- After 30 days, follow-up should continue at 6 months, 1 year, and annually thereafter 1
- The frequency of follow-up evaluations should be increased if there is significant post-TAVR paravalvular leak or any change in clinical status or echocardiographic findings 1
Potential Pitfalls and Caveats
- Direct oral anticoagulants (DOACs) should not be used in patients with mechanical valve prostheses due to increased risk of thrombotic complications 1
- For patients with high bleeding risk, consideration of single antiplatelet therapy rather than dual antiplatelet therapy may be reasonable 2, 4
- When vitamin K antagonist therapy is used, continuation of aspirin is reasonable, but it may be prudent to avoid other antiplatelet therapy in some patients given the increased risk of bleeding with multiple simultaneous antithrombotic agents 1
- Careful monitoring for bleeding complications is essential, especially in elderly TAVR patients who often have multiple comorbidities 2
Emerging Evidence
- Recent data suggest that dual-antiplatelet therapy may be associated with an increased risk for bleeding events compared with single-antiplatelet therapy with aspirin, particularly early after the procedure 4
- Several ongoing trials are evaluating different antithrombotic strategies after TAVR, including the use of direct oral anticoagulants 6, 5
- Limited evidence suggests that DOAC therapy after TAVR may be safe and well-tolerated in patients who have indications for anticoagulation and are poor warfarin candidates 7