What is the efficacy of the Watchman device for stroke prevention in patients with non-valvular atrial fibrillation (AF)?

Efficacy of Watchman Device for Stroke Prevention in Non-Valvular Atrial Fibrillation

The Watchman device may be considered for stroke prevention in patients with non-valvular atrial fibrillation who have contraindications to long-term oral anticoagulation therapy, but it is not a first-line therapy for most patients. 1, 2

Patient Selection and Indications

• The Watchman device is recommended for patients with:

  • Non-valvular atrial fibrillation
  • Increased stroke risk (CHA₂DS₂-VASc score ≥2 for men or ≥3 for women)
  • Contraindications to long-term oral anticoagulation therapy 2

• Contraindications to long-term oral anticoagulation may include:

  • History of major bleeding events
  • High bleeding risk (HAS-BLED score ≥3)
  • Inability to maintain stable INR on warfarin
  • Poor medication adherence or tolerance 2

Efficacy Evidence

• The Watchman device has been evaluated in randomized trials (PROTECT AF and PREVAIL) comparing it to warfarin:

  • Demonstrated significantly lower rates of hemorrhagic stroke compared to warfarin
  • Reduced cardiovascular death and bleeding beyond the immediate post-procedural period 2
  • When periprocedural events were excluded, there was no significant difference in ischemic stroke rates 1

• Recent evidence from the EWOLUTION trial showed:

  • Low rates of stroke (1.3/100 patient-years, 83% reduction versus historic data)
  • Reduced major nonprocedural bleeding events (2.7/100 patient-years, 46% reduction versus historic data) 2

• A 2024 retrospective cohort study comparing Watchman to DOACs in high-risk patients found:

  • Lower rates of major bleeding events (OR 0.24)
  • Lower rates of TIAs (OR 0.75)
  • Lower rates of ischemic strokes (OR 0.72) 3

Important Considerations and Limitations

• Oral anticoagulation remains the preferred therapy for stroke prevention for most patients with AF and elevated stroke risk 1

• There are important differences between FDA and CMS approval criteria:

  • FDA approval: Patients must be suitable for long-term warfarin but have a rationale to seek a non-pharmacological alternative
  • CMS approval: Patients must be suitable for short-term warfarin but deemed unable to take long-term oral anticoagulation 1, 2

• Post-implantation management requires:

  • Warfarin plus aspirin for 45 days
  • Followed by dual antiplatelet therapy for 6 months
  • Then aspirin indefinitely 2

• Potential complications include:

  • Pericardial effusion (4.4-7.1% of cases)
  • Device embolization
  • Procedure-related ischemic stroke
  • Device-related thrombus formation (approximately 3.4% of patients) 2, 4

Current Guideline Recommendations

• American Heart Association/American College of Cardiology/Heart Rhythm Society (2019):

  • Class IIb recommendation (may be considered)
  • Level B-NR evidence
  • For patients with non-valvular AF at increased risk of stroke who have contraindications to long-term oral anticoagulation 1, 2

• American Heart Association/American Stroke Association (2021):

  • Class 2b, Level B-R recommendation
  • For patients with stroke or TIA in the setting of non-valvular AF who have contraindications for lifelong anticoagulation but can tolerate at least 45 days of anticoagulation 1

The ongoing CHAMPION-AF trial is directly comparing Watchman FLX to DOACs in a broader AF population, which may provide more definitive evidence on whether LAAC could be considered as a first-line alternative to DOACs 5.