Indications for Watchman Procedure in Non-Valvular Atrial Fibrillation
The Watchman procedure is indicated for patients with non-valvular atrial fibrillation who are at increased risk of stroke (CHADS₂ score ≥2 or CHA₂DS₂-VASc score ≥3) and have contraindications to long-term oral anticoagulation therapy. 1
Patient Selection Criteria
Primary Indications
- Patients with non-valvular AF at high risk of stroke who have:
- Contraindications to long-term oral anticoagulation 1
- History of major bleeding while on anticoagulation therapy
- High risk of bleeding (HAS-BLED score ≥3)
- Poor medication adherence or inability to maintain therapeutic INR levels on warfarin
Risk Assessment Requirements
- CHADS₂ score ≥2 or CHA₂DS₂-VASc score ≥3 1
- Patients must be suitable for short-term warfarin therapy (at least 45 days post-procedure) 1, 2
Contraindications
- Moderate to severe mitral stenosis
- Mechanical heart valves
- Inability to tolerate short-term anticoagulation or dual antiplatelet therapy
- Left atrial thrombus
Clinical Evidence Supporting Use
The recommendation for Watchman is classified as Class IIb (may be considered) with Level B-NR evidence according to the 2019 AHA/ACC/HRS guidelines 1. This indicates that the procedure may be reasonable in selected patients, but the evidence is not as strong as for first-line therapies.
Key findings from clinical trials:
- PROTECT AF and PREVAIL trials demonstrated non-inferiority to warfarin for the composite endpoint of stroke, systemic embolism, and cardiovascular death 1
- Meta-analysis of these trials showed:
Important Considerations and Limitations
Procedural Risks
- Pericardial effusion (4.4-7.1% in early studies) 1
- Device embolization
- Procedure-related ischemic stroke
- Device-related thrombus formation (up to 7.2% per year) 1
Post-Procedure Anticoagulation Requirements
- First 45 days: Warfarin (target INR 2.0-3.0) plus aspirin (81-100mg daily) 2
- 45 days to 6 months: Dual antiplatelet therapy (aspirin plus clopidogrel) after TEE confirms adequate LAA closure 2
- Beyond 6 months: Aspirin monotherapy indefinitely 2
Regulatory Differences
There are important differences between FDA and CMS approval criteria:
- FDA approval: For patients suitable for warfarin but with appropriate rationale to seek a non-pharmacological alternative 1
- CMS approval: For patients suitable for short-term warfarin but deemed unable to take long-term oral anticoagulation 1
Clinical Algorithm for Decision-Making
- Assess stroke risk: Calculate CHA₂DS₂-VASc score (must be ≥3 for women or ≥2 for men)
- Evaluate bleeding risk: Calculate HAS-BLED score
- Determine anticoagulation status:
- First consider oral anticoagulation (preferably NOACs) as first-line therapy 1
- If patient has contraindications to long-term anticoagulation, consider Watchman
- Verify patient can tolerate short-term anticoagulation (45 days of warfarin post-procedure)
- Exclude patients with valvular AF (moderate-severe mitral stenosis or mechanical valves)
Pitfalls and Caveats
- No direct comparison trials between Watchman and NOACs exist 1
- The procedure has a learning curve with higher complication rates for less experienced operators 1
- Incomplete occlusion of the LAA can occur and may not eliminate stroke risk completely
- Device-related thrombus can form and requires monitoring with TEE at 45 days and potentially at 12 months 3
- The need for post-procedure antiplatelet therapy still carries bleeding risk, which must be considered when selecting patients 1
In summary, while oral anticoagulation remains the preferred therapy for most AF patients at risk of stroke, the Watchman procedure provides a reasonable alternative for those who cannot tolerate long-term anticoagulation due to bleeding risk or other contraindications.