What are the indications for the Watchman device in patients with non-valvular atrial fibrillation (AF) and contraindications to anticoagulant therapy?

Indications for the Watchman Device

The Watchman device may be considered in patients with non-valvular atrial fibrillation at increased risk of stroke (CHA₂DS₂-VASc score ≥2 for men or ≥3 for women) who have contraindications to long-term oral anticoagulation, though it remains a second-line option with oral anticoagulation being the preferred first-line therapy. 1

Primary Patient Selection Criteria

Stroke Risk Requirements

• CHA₂DS₂-VASc score ≥2 for men or ≥3 for women is required to establish sufficient stroke risk to warrant intervention 1, 2
• The mean CHA₂DS₂-VASc score in the ASAP study was 4.4 ± 1.7, reflecting the high-risk population typically considered 3

Anticoagulation Status Requirements

The FDA and CMS have different wording that creates important distinctions 1:

FDA Approval Criteria:

• Patients must be deemed suitable for long-term warfarin (able to tolerate it medically)
• Must have an appropriate rationale to seek a non-pharmacologic alternative to warfarin 1
• Must be able to tolerate at least 45 days of post-procedural anticoagulation 1, 2

CMS Coverage Criteria:

• Patients must be suitable for short-term warfarin but deemed unable to take long-term oral anticoagulation 1
• This reflects real-world practice where the device targets patients who cannot sustain chronic anticoagulation 1

Specific Contraindications to Anticoagulation

The most common reasons for warfarin ineligibility include 3:

• History of hemorrhagic bleeding or bleeding tendencies (93% of patients in ASAP study) 3
• Recurrent falls or high fall risk 2
• Poor drug tolerance or adherence to oral anticoagulants 1
• Absolute contraindications to all oral anticoagulants 2

Exclusion Criteria

The following patients are NOT candidates for the Watchman device:

• Patients with moderate to severe mitral stenosis 1
• Patients with mechanical heart valves 1
• Patients who cannot tolerate any anticoagulation, even short-term (per FDA labeling, though real-world experience exists with antiplatelet-only regimens outside the US) 1

Clinical Context and Limitations

Oral Anticoagulation Remains First-Line

Oral anticoagulation is the preferred therapy for stroke prevention in most patients with AF and elevated stroke risk. 1 The Watchman device should only be considered when patients are poor candidates for long-term oral anticoagulation due to bleeding propensity, poor drug tolerance, or adherence issues 1

Evidence Limitations

• No randomized trials compare the Watchman device to direct oral anticoagulants (DOACs), which have better safety profiles than warfarin 2
• The PROTECT AF and PREVAIL trials only compared the device to warfarin, not modern DOACs 1, 2
• The CHAMPION-AF trial is ongoing to compare Watchman FLX to DOACs in a broader population 4

Periprocedural Risks

• Serious periprocedural complications occur in approximately 6-7% of cases, including pericardial effusion requiring drainage, device embolization, and major bleeding 2, 5
• The ASAP study reported serious procedure- or device-related safety events in 8.7% of patients 3

Device-Related Thrombus Risk

• Thrombus formation on the device occurs in up to 7.2% per year and is associated with increased ischemic stroke risk 2, 6
• Risk factors include non-paroxysmal AF (OR 1.90-2.24), renal insufficiency (OR 4.02), history of TIA/stroke (OR 2.31), and deep device implantation >10mm from pulmonary vein limbus (OR 2.41) 6

Post-Implantation Requirements

Mandatory Anticoagulation Protocol

Despite being placed for anticoagulation contraindications, patients require 2, 6:

• Warfarin (INR 2.0-3.0) plus aspirin for 45 days post-implantation 2, 6
• Dual antiplatelet therapy (aspirin plus clopidogrel) from 45 days to 6 months 2, 6
• Aspirin monotherapy indefinitely after 6 months 2, 6

Surveillance Requirements

• Transesophageal echocardiography (TEE) at 45 days and 1 year to evaluate for device-related thrombus and peridevice leak before discontinuing anticoagulation 5, 6
• Any peridevice leak detected is associated with increased thromboembolism risk 5, 6

Guideline Recommendation Strength

The recommendation carries a Class IIb indication with Level of Evidence B-NR, meaning it "may be considered" but is not strongly recommended 1. This reflects:

• Limited evidence compared to oral anticoagulants 2
• Lack of comparison to modern DOACs 2
• Significant periprocedural risks 2, 3
• Need for post-procedural anticoagulation despite bleeding contraindications 2, 6