Watchman Procedure for Stroke Prevention in Non-Valvular Atrial Fibrillation
The Watchman procedure is used to mechanically close the left atrial appendage (LAA) in patients with non-valvular atrial fibrillation who are at high risk for stroke but have contraindications to long-term oral anticoagulation therapy or high bleeding risk. 1
Patient Selection Criteria
The American Heart Association, American College of Cardiology, and Heart Rhythm Society recommend the Watchman procedure for:
- Patients with non-valvular atrial fibrillation who have:
- Increased stroke risk (CHA₂DS₂-VASc score ≥3 for women or ≥2 for men)
- Contraindications to long-term oral anticoagulation therapy
- High bleeding risk (HAS-BLED score ≥3)
- An appropriate rationale to seek a non-pharmacological alternative to warfarin 1
Mechanism of Action
The Watchman device works by mechanically occluding the left atrial appendage, which is the source of approximately 90% of thrombi in patients with non-valvular atrial fibrillation. By closing off this structure, the device aims to prevent thrombus formation and subsequent stroke or systemic embolism. 1, 2
Procedure Details
The procedure is performed under general anesthesia with transesophageal echocardiography (TEE) guidance and involves:
- Transseptal puncture to access the left atrium
- Device sizing based on LAA anatomy
- Deployment of the Watchman device at the ostium of the LAA 1
Post-Procedure Anticoagulation Regimen
The standard anticoagulation protocol after Watchman implantation includes:
| Time Period | Recommended Regimen |
|---|---|
| 0-45 days | Warfarin (target INR 2.0-3.0) + Aspirin (81-100mg daily) |
| 45 days-6 months | Dual antiplatelet therapy: Aspirin (81-325mg daily) + Clopidogrel (75mg daily) |
| >6 months | Aspirin (81-325mg daily) indefinitely [1] |
At 45 days post-procedure, a TEE is performed to:
- Check device position
- Assess for peri-device leak (should be ≤5mm)
- Detect any device-related thrombus 1, 3
Clinical Efficacy
The Watchman device has demonstrated:
- Non-inferiority to warfarin for the composite endpoint of stroke, systemic embolism, and cardiovascular death
- Significantly lower hemorrhagic stroke rates
- Reduced cardiovascular death
- Reduced bleeding beyond the immediate post-procedural period 1
Real-world data from the EWOLUTION trial showed:
- 83% reduction in stroke rates compared to historic data
- 46% reduction in major bleeding events
- Particularly beneficial outcomes in patients with prior ischemic stroke (76% reduction in stroke) or hemorrhagic stroke (81% reduction in stroke) 4
Potential Complications
Important procedure-related complications include:
- Pericardial effusion (4.4-7.1% of patients)
- Device embolization
- Procedure-related ischemic stroke
- Device-related thrombus formation (observed in approximately 4.1% of patients) 1, 2, 4
Special Considerations
For patients with absolute contraindications to oral anticoagulants:
- Dual antiplatelet therapy (aspirin and clopidogrel) for six months followed by aspirin indefinitely may be considered 3
Direct oral anticoagulants (DOACs) may be a convenient and non-inferior substitute for warfarin in the post-implantation period, though evidence is still limited 3
Important Caveats
The Watchman procedure is considered a Class IIb recommendation (may be considered) with Level B-NR evidence according to the 2019 AHA/ACC/HRS guidelines 1
Oral anticoagulation (preferably NOACs) remains the first-line therapy for stroke prevention in atrial fibrillation 1
A multidisciplinary team approach is recommended for patient selection, as operator experience significantly impacts complication rates 1
Regular follow-up with imaging is essential to monitor for device-related complications, particularly thrombus formation 1, 3