What is the stroke rate with a Watchman (Left Atrial Appendage Closure Device)?

From the Guidelines

The Watchman device is associated with an annual stroke rate of approximately 1.5-2.2% per year, which is non-inferior to warfarin therapy, as demonstrated in the most recent and highest quality study 1.

Key Points

• The Watchman device reduces stroke risk in patients with atrial fibrillation by closing off the left atrial appendage, where over 90% of stroke-causing blood clots form in atrial fibrillation patients.
• After Watchman implantation, patients typically follow an anticoagulation regimen that starts with warfarin for 45 days, followed by dual antiplatelet therapy (aspirin plus clopidogrel) for 6 months, and then lifelong aspirin therapy.
• The device is particularly beneficial for patients who have contraindications to long-term anticoagulation, history of bleeding complications, or difficulty maintaining therapeutic anticoagulation levels.
• While the Watchman effectively reduces cardioembolic strokes, patients remain at risk for other stroke types (like those caused by hypertension or atherosclerosis), so controlling cardiovascular risk factors remains important.

Evidence Summary

• A meta-analysis combining data from the PROTECT AF and PREVAIL trials and their registries demonstrated that patients receiving the Watchman device had significantly fewer hemorrhagic strokes than did those receiving warfarin, but there was an increase in ischemic strokes in the device group 1.
• The 2024 ESC guidelines for the management of atrial fibrillation recommend the Watchman device as an alternative for patients who are poor candidates for long-term oral anticoagulation 1.
• Observational studies have also supported the use of antiplatelet therapy without associated increases in device-related thrombosis or stroke 1.

Clinical Implications

• The Watchman device provides an alternative for stroke prevention in patients with atrial fibrillation who are at high risk of stroke and have contraindications to long-term anticoagulation.
• The device should be considered as part of a comprehensive stroke prevention strategy that includes controlling cardiovascular risk factors and optimizing antithrombotic therapy.
• Further studies are needed to determine the optimal patient selection and periprocedural antithrombotic regimen for the Watchman device.

From the Research

Stroke Rate with Watchman Device

• The stroke rate with the Watchman device has been studied in several research papers, with varying results:
  • A study published in 2019 2 found that the total stroke rate was significantly less than predicted by CHA2DS2-VASc score, with a 78% reduction in the CAP registry and a 69% reduction in the CAP2 registry.
  • Another study published in 2024 3 compared 5-year major bleeding and ischemic stroke rates in patients with nonvalvular atrial fibrillation who received a WATCHMAN device or DOAC therapy, and found that the WATCHMAN cohort had significantly lower rates of major bleeding events, TIAs, and ischemic strokes.
  • A study published in 2022 4 reported on patients with the Watchman LAAO device who were on single-antiplatelet therapy or no therapy, and found that patients experienced 1.4 ischemic strokes per 100 patient years despite a CHA2DS2-VASC score of 4.3 ± 1.6.
• The efficacy and safety of the Watchman device have been demonstrated in several studies, including a single-centre registry published in 2016 5, which found that the procedure was safe and effective, with no adverse events occurring during the index hospitalization or at 45 days.

Comparison to Other Therapies

• The Watchman device has been compared to other therapies, such as direct oral anticoagulants (DOACs) and warfarin:
  • A study published in 2023 6 found that the WATCHMAN device is non-inferior to warfarin and is a safe alternative for the prevention of stroke and systemic embolization related to non-valvular atrial fibrillation (NVAF).
  • The study published in 2024 3 found that the WATCHMAN device was comparable to DOAC therapy in the primary prevention of hemorrhagic strokes and may provide benefit in the rates of bleeding events, TIAs, and ischemic strokes.

Patient Outcomes

• Patient outcomes with the Watchman device have been studied in several research papers:
  • The study published in 2019 2 found that the primary composite endpoint occurred at a rate of 3.05 per 100 patient-years in the CAP registry and 4.80 per 100 patient-years in the CAP2 registry.
  • The study published in 2022 4 found that patients on single-antiplatelet therapy or no therapy after Watchman implantation experienced low rates of ischemic strokes and major bleeding events.