What are the current recommendations for antiplatelet vs anticoagulation therapy in patients with a Watchman (Left Atrial Appendage Closure Device) implant?

Antiplatelet vs Anticoagulation After Watchman Implantation

Following Watchman device implantation, the standard protocol requires warfarin (INR 2.0-3.0) plus aspirin for 45 days, followed by dual antiplatelet therapy (aspirin plus clopidogrel) from 45 days to 6 months, then aspirin monotherapy indefinitely. 1, 2

Standard Three-Phase Anticoagulation Protocol

The established regimen is based on the PROTECT-AF and PREVAIL trials that demonstrated non-inferiority to warfarin for stroke prevention 1, 2:

Phase 1: Days 0-45

• Warfarin (target INR 2.0-3.0) plus aspirin 81-162 mg daily 1, 2
• A transesophageal echocardiogram (TEE) must be performed at 45 days to evaluate for device-related thrombus and peridevice leak before discontinuing anticoagulation 1
• This initial period carries high bleeding risk and requires close monitoring 1

Phase 2: Days 45 to 6 Months

• Dual antiplatelet therapy with aspirin 81-162 mg plus clopidogrel 75 mg daily 1, 2
• Warfarin is discontinued at 45 days only if TEE shows minimal peridevice leak (≤5mm) and no device-related thrombus 3
• This transition reduces intracranial and extracranial hemorrhage risk 1

Phase 3: Beyond 6 Months

• Aspirin 81-162 mg daily indefinitely 1, 2
• Another TEE is recommended at 1 year for continued surveillance 1

Alternative Regimens for High Bleeding Risk Patients

For patients with absolute contraindications to oral anticoagulation (the primary indication for Watchman), dual antiplatelet therapy alone for 6 months followed by aspirin indefinitely may be considered. 3, 4

• Real-world data suggests that shortened anticoagulation duration (discontinuation at 45 days in 70% of patients) and early cessation of dual antiplatelet therapy (discontinuation at 90 days in 89% of patients) did not significantly increase stroke risk 4
• Some centers use 3 months of DAPT alone or DOACs at full or reduced dose as alternatives to warfarin during the initial 45-day period 2
• In patients with prior intracranial hemorrhage, 19% were managed with DAPT alone post-procedurally with 95% remaining free of death, stroke, or major bleeding at 6 months 5

Critical Monitoring Requirements

Any peridevice leak detected by TEE, regardless of size, is associated with increased risk of thromboembolism and requires careful characterization. 1

High-Risk Features Requiring Extended Surveillance

• Non-paroxysmal atrial fibrillation increases device-related thrombus risk (OR 1.90-2.24) 1, 6
• Renal insufficiency increases device-related thrombus risk (OR 4.02) 1, 6
• History of TIA or stroke increases device-related thrombus risk (OR 2.31) 1, 6
• Deep device implantation >10mm from pulmonary vein limbus increases device-related thrombus risk (OR 2.41) 1

Device-Related Thrombus Management

Device-related thrombus occurs in 1.7-7.2% of patients per year and is significantly associated with increased stroke risk (HR 4.6). 1, 6

• If device-related thrombus is detected, switching from dual antiplatelet therapy to a DOAC (such as apixaban) can achieve complete thrombus resolution 7
• After thrombus resolution, patients can return to dual antiplatelet therapy for the remainder of the 6-month period, then aspirin monotherapy 7

Important Clinical Caveats

The FDA approval specifies that patients must be deemed suitable for at least short-term warfarin and can tolerate at least 45 days of postprocedural anticoagulation. 1

• The paradox of requiring post-procedural antithrombotic therapy exposes patients to bleeding risks that may be equivalent to DOACs, which creates a clinical dilemma for patients who received the device specifically due to bleeding contraindications 2, 6
• Serious periprocedural complications occur in approximately 6-7% of cases, including device embolization, major bleeding, and pericardial effusions requiring drainage 2
• Patients with concurrent coronary artery disease requiring DAPT for stent thrombosis prevention should remain on DAPT beyond 6 months 2

Guideline Recommendations

The 2019 AHA/ACC/HRS guidelines state that percutaneous LAA occlusion may be considered (Class IIb, Level B-NR) in patients with atrial fibrillation at increased risk of stroke who have contraindications to long-term anticoagulation 1, 2. The 2024 ESC Guidelines note that with DOACs demonstrating similar bleeding rates to aspirin, the role of Watchman in current practice is unclear, as the device trials compared against warfarin, not modern DOACs 1.