For a patient with non‑valvular atrial fibrillation, CHA2DS2‑VASc (Congestive heart failure, Hypertension, Age ≥ 75 years, Diabetes mellitus, prior Stroke/TIA, Vascular disease, Age 65‑74 years, Sex category) score ≥ 2 (or 1 in women) and contraindication to long‑term oral anticoagulation because of high bleeding risk (HAS‑BLED [Hypertension, Abnormal renal/liver function, Stroke, Bleeding history, Labile INR, Elderly, Drugs/alcohol] score ≥ 3), is the Watchman left atrial appendage occlusion device indicated and what is the recommended post‑implant antithrombotic regimen?

Watchman Device for Left Atrial Appendage Closure in High-Risk AF Patients

The Watchman left atrial appendage occlusion device is indicated for patients with non-valvular atrial fibrillation, CHA₂DS₂-VASc score ≥2, and contraindications to long-term oral anticoagulation due to high bleeding risk (HAS-BLED ≥3). 1, 2

Device Indication and Patient Selection

The FDA-approved indication specifically includes patients with non-valvular AF who are at risk for stroke, suitable for short-term anticoagulation, but have a rationale for seeking a non-pharmacologic alternative to long-term oral anticoagulation. 1

Qualifying Criteria:

• CHA₂DS₂-VASc score ≥2 (or ≥1 in women when counting sex as a point) indicating elevated thromboembolic risk 1
• HAS-BLED score ≥3 indicating high bleeding risk, which represents a contraindication to long-term anticoagulation 2
• Absolute contraindications to anticoagulation include: active major bleeding, severe uncontrolled hypertension (>180/120 mmHg), history of intracranial hemorrhage with high recurrence risk, end-stage liver disease with coagulopathy, severe thrombocytopenia (<50,000/μL), or hypersensitivity to all available anticoagulants 2

Important Context:

The pivotal PROTECT AF trial demonstrated non-inferiority of Watchman to warfarin for stroke prevention, but enrolled only warfarin-eligible patients. 3 The ASAP study specifically evaluated patients deemed ineligible for warfarin (mean CHADS₂ 2.8, CHA₂DS₂-VASc 4.4), with 93% having history of hemorrhagic/bleeding tendencies, and demonstrated an ischemic stroke rate of 1.7% per year compared to an expected 7.3% per year based on risk scores. 3

Post-Implant Antithrombotic Regimen

The recommended post-implant antithrombotic strategy differs based on the patient's ability to tolerate any anticoagulation:

Standard Post-Implant Protocol (for patients who can tolerate short-term anticoagulation):

• Warfarin (INR 2.0-3.0) for 45 days post-implantation 4, 5
• Transition to dual antiplatelet therapy (aspirin plus clopidogrel) after 45-day transesophageal echocardiography (TEE) confirms adequate LAA closure without device-related thrombus 4, 5
• Continue dual antiplatelet therapy until 6 months post-implant 3
• Transition to aspirin monotherapy indefinitely after 6 months 3

Alternative Protocol for Patients Unable to Tolerate Warfarin:

The ASAP study protocol used dual antiplatelet therapy (aspirin 325 mg plus clopidogrel 75 mg) immediately post-procedure without warfarin transition, demonstrating safety and efficacy in patients with absolute contraindications to anticoagulation. 3

• Aspirin 325 mg plus clopidogrel 75 mg daily for 6 months post-implant 3
• Transition to aspirin 325 mg monotherapy indefinitely after 6 months 3

NOAC Alternative:

Direct oral anticoagulants (DOACs) may be used as an alternative to warfarin for the initial 45-day period, with 55% of patients in contemporary registries receiving NOACs post-procedure. 6

Procedural Safety and Outcomes

Device implantation success rates exceed 98% in experienced centers, with serious adverse event rates of 1.4-8.7% at 30 days. 4, 6, 5

Key Safety Metrics:

• Device-related thrombus formation occurs in approximately 4% of patients at 45-day follow-up 4
• Pericardial effusion requiring intervention occurs in <2% of cases 6, 5
• Device embolization is rare (<1%) with proper sizing and technique 4, 5
• Peridevice leak >5mm occurs in approximately 25% initially but typically resolves by 45-day follow-up 5

Critical Follow-Up Requirements

Mandatory TEE at 45 days post-implant to assess:

• Device position and stability 4, 5
• Presence of device-related thrombus 4, 5
• Peridevice leak assessment 5
• Determination of whether anticoagulation can be safely discontinued 4

Additional follow-up TEE at 6 months and 12 months to monitor for late complications and confirm continued adequate LAA closure. 4

Common Pitfalls to Avoid

• Do not implant Watchman in patients with valvular AF (moderate-to-severe mitral stenosis or mechanical valves), as these patients require lifelong anticoagulation regardless 1, 7
• Do not discontinue anticoagulation before 45-day TEE confirmation of adequate device positioning without thrombus 4, 5
• Do not use aspirin monotherapy as stroke prevention in AF patients—it is ineffective and still carries bleeding risk 1, 8
• Do not assume all patients with HAS-BLED ≥3 are contraindicated for anticoagulation—address modifiable bleeding risk factors first (hypertension control, alcohol cessation, medication adjustments) 2, 8
• Do not proceed with Watchman implantation without confirming patient can tolerate at least short-term antithrombotic therapy (either warfarin/NOAC for 45 days or dual antiplatelet therapy for 6 months) 3

Institutional Requirements

Watchman implantation should only be performed at centers with:

• Multidisciplinary team including interventional cardiology, electrophysiology, and cardiac imaging expertise 1
• Immediate cardiac surgery backup capability for emergency complications 1
• Operators with specific training and credentialing in LAA closure techniques 1
• TEE capability for procedural guidance and follow-up assessment 1, 5