What is the recommended dual antiplatelet therapy (DAPT) regimen for patients undergoing Transcatheter Aortic Valve Replacement (TAVR)?

Dual Antiplatelet Therapy After Transcatheter Aortic Valve Replacement

Clopidogrel 75 mg daily for 3-6 months plus lifelong aspirin 75-100 mg daily is the recommended dual antiplatelet therapy (DAPT) regimen for patients undergoing TAVR without other indications for anticoagulation. 1

Standard Antithrombotic Regimen After TAVR

Primary Recommendation

• First 3-6 months post-TAVR:

  • Clopidogrel 75 mg daily PLUS
  • Aspirin 75-100 mg daily

• Beyond 3-6 months:

  • Aspirin 75-100 mg daily (lifelong)

This recommendation is based on clinical trial protocols used in the pivotal TAVR studies, where balloon-expandable valves typically used 6 months of DAPT and self-expanding valves used 3 months of DAPT 1.

Evidence Quality and Considerations

The recommendation for DAPT carries a Class IIb, Level of Evidence C designation in the 2014 AHA/ACC guidelines, indicating that it "may be reasonable" but is based on limited evidence 1. The 2017 ACC Expert Consensus Decision Pathway reaffirms this as the "current standard antithrombotic therapy" 1.

Special Circumstances

Patients with Existing Anticoagulation

For patients with chronic atrial fibrillation or other indications for long-term anticoagulation:

• Continue anticoagulation as per guidelines for AF in patients with prosthetic heart valves 1
• When vitamin K antagonist therapy is used, continuation of aspirin is reasonable
• Consider avoiding additional antiplatelet therapy due to increased bleeding risk with multiple antithrombotic agents 1

Subclinical Valve Thrombosis Concerns

• Subclinical leaflet thrombus formation may be more common after TAVR than previously appreciated 1
• Patients on vitamin K antagonist therapy have shown lower rates of reduced leaflet motion compared to those on antiplatelet therapy alone 1
• The 2017 AHA/ACC focused update states that anticoagulation with a 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 (Class IIb, Level of Evidence B-NR) 1

Emerging Evidence

Recent research challenges the standard DAPT recommendation:

• A 2020 randomized controlled trial (POPular TAVI) found that aspirin alone compared to DAPT resulted in:

  • Significantly less bleeding (15.1% vs 26.6%)
  • No increase in thromboembolic events
  • Better composite outcomes of cardiovascular death, non-procedure-related bleeding, stroke, or myocardial infarction 2

• Meta-analyses comparing SAPT vs DAPT after TAVR have shown:

  • Increased risk of significant bleeding with DAPT (RR = 2.52)
  • No significant difference in stroke, myocardial infarction, or all-cause mortality 3
  • Lower 30-day mortality with SAPT along with reduced bleeding risk and no increased risk of stroke 4

Common Pitfalls to Avoid

1. Inappropriate use of direct oral anticoagulants (DOACs):

   • Anticoagulant therapy with oral direct thrombin inhibitors or anti-Xa agents should NOT be used in patients with mechanical valve prostheses (Class III: Harm, Level of Evidence B) 1

2. Failure to adjust therapy for patients with multiple indications:

   • Patients with recent coronary stenting or acute coronary syndrome may require different DAPT durations based on their cardiac condition 1

3. Not recognizing increased bleeding risk:

   • DAPT increases bleeding risk compared to single antiplatelet therapy
   • Consider patient-specific bleeding risk factors when determining duration of therapy

Algorithm for Decision-Making

1. Assess if patient has indication for long-term anticoagulation:

   • If YES → Follow anticoagulation guidelines for patients with prosthetic heart valves; consider adding single antiplatelet therapy
   • If NO → Continue to step 2

2. Evaluate bleeding risk:

   • If HIGH bleeding risk → Consider aspirin alone (75-100 mg daily)
   • If LOW-MODERATE bleeding risk → Continue to step 3

3. Standard DAPT approach:

   • Clopidogrel 75 mg daily for 3-6 months
   • Aspirin 75-100 mg daily (lifelong)
   • Consider shorter DAPT duration (3 months) for patients with moderate bleeding risk

4. After completion of DAPT period:

   • Continue aspirin 75-100 mg daily indefinitely
   • Monitor for valve thrombosis and thromboembolic events

This approach balances the need to prevent valve thrombosis and thromboembolic events while minimizing bleeding risk in patients undergoing TAVR.