What is the recommended anticoagulation therapy after Watchman (Left Atrial Appendage Closure Device) placement?

Anticoagulation After Watchman Device Placement

After Watchman left atrial appendage closure device placement, patients should receive warfarin plus aspirin for at least 45 days, followed by dual antiplatelet therapy (aspirin plus clopidogrel) until 6 months post-procedure, and then aspirin alone indefinitely. 1

Standard Post-Implantation Anticoagulation Protocol

The evidence-based anticoagulation regimen following Watchman device implantation follows this sequence:

1. Initial 45 days:

   • Warfarin (target INR 2.0-3.0) plus aspirin 81-100 mg daily
   • Transesophageal echocardiography (TEE) at 45 days to assess device position and any thrombus formation

2. 45 days to 6 months:

   • If TEE shows adequate LAA closure (≤5mm residual peridevice flow) and no device-related thrombus:
   • Discontinue warfarin
   • Start clopidogrel 75 mg daily (continue aspirin)

3. After 6 months:

   • Discontinue clopidogrel
   • Continue aspirin 81-100 mg daily indefinitely

This protocol is based on the pivotal PROTECT-AF trial methodology, which demonstrated that LAA closure with the Watchman device was non-inferior to warfarin for preventing stroke, systemic embolism, and cardiovascular death 1.

Alternative Anticoagulation Options

DOACs as Alternative to Warfarin

Recent evidence suggests that direct oral anticoagulants (DOACs) may be a viable alternative to warfarin during the initial 45-day period:

• A meta-analysis of 10 cohort studies with 2,440 patients found that DOACs were associated with:
  • Reduced major bleeding (RR 0.52; 95% CI 0.30-0.89)
  • Reduced overall bleeding (RR 0.38; 95% CI 0.25-0.58)
  • Comparable rates of thromboembolism, device-related thrombus, and mortality 2

However, it's important to note that the pivotal trials used warfarin, and current guidelines still primarily recommend warfarin for the initial anticoagulation period.

Patients with Contraindications to Anticoagulation

For patients with absolute contraindications to oral anticoagulation:

• Dual antiplatelet therapy (aspirin plus clopidogrel) for 6 months followed by aspirin alone may be considered 3, 4
• This approach carries higher risk of device-related thrombus and should be carefully monitored with more frequent TEE imaging

Monitoring and Management of Complications

Device-Related Thrombus (DRT)

Device-related thrombus occurs in approximately 3-4% of patients 5 and requires prompt management:

• If DRT is detected on follow-up imaging:
  • Reinitiate or continue anticoagulation (warfarin or DOAC)
  • Repeat TEE in 1-3 months to confirm resolution
  • Case reports suggest DOACs like apixaban may successfully treat DRT 6

Risk Factors for Device-Related Thrombus

Factors associated with higher risk of device-related thrombus include:

• Persistent/permanent atrial fibrillation (vs. paroxysmal)
• Larger device size
• Premature discontinuation of anticoagulation/antiplatelet therapy 5

Important Considerations and Pitfalls

1. TEE follow-up is crucial: Ensure TEE is performed at 45 days to assess for proper device sealing and absence of thrombus before changing anticoagulation regimen.

2. Bleeding risk assessment: While the standard protocol is recommended, bleeding risk must be considered, especially during the period of combined anticoagulant and antiplatelet therapy.

3. Device selection: The Watchman device is indicated for patients who:

   • Are at increased risk for stroke based on CHA₂DS₂-VASc score
   • Are deemed suitable for warfarin therapy
   • Have an appropriate rationale to seek a non-pharmacological alternative to warfarin 1

4. Limited evidence in high bleeding risk patients: The pivotal trials excluded patients with absolute contraindications to anticoagulation, who would otherwise be ideal candidates for LAA closure 1.

The Watchman device represents an important alternative to long-term anticoagulation for stroke prevention in atrial fibrillation, but proper post-implantation anticoagulation management is essential to prevent device-related thrombosis while minimizing bleeding risk.