The PROTECT AF clinical trial, involving 707 randomized patients that were treated with either the WATCHMAN Device or standard Warfarin therapy, was performed to evaluate the safety and effectiveness of the WATCHMAN LAA Closure Technology. Consistent with the data recently reported in the Lancet, the primary analyses support a statistically significant finding of non-inferiority for the WATCHMAN group relative to the Control group for the primary efficacy endpoint, and this finding was consistent across a wide range of secondary analyses. Data from the Control group demonstrate both the difficulties associated with the use of and complications due to Warfarin therapy. Control patients experienced time in therapeutic range of 66% which was consistent with other randomized, controlled clinical trials.

The PROTECT AF clinical trial results with 1065 patient years of follow up support the following statements:⁴

• The WATCHMAN Device was associated with a 38% reduction in endpoint events (stroke, cardiovascular death, and systemic embolism) compared to patients on a standard Warfarin therapy.
• The WATCHMAN Device was successfully implanted in 91% of patients in whom an implant was attempted.
• After successful implant of the WATCHMAN Device, 87% of patients were able to discontinue Warfarin therapy after 45 days. This percentage increased as follow-up continued.
• While there was an increased risk associated with the WATCHMAN implant procedure, these risks declined over the course of the trial as investigators gained experience with the procedure and the device.
• Patients who were successfully implanted and in whom Warfarin was discontinued, resulted in a 60% reduction in the rate of the composite endpoint of all stroke, cardiovascular death and systemic embolism.

The PROTECT AF data demonstrate that the WATCHMAN LAA Closure Technology is a safe and effective alternative to Warfarin therapy for use in reducing the risk of stroke, cardiovascular death and systemic thromboembolism in patients with non-valvular atrial fibrillation.

4. Holmes D R et al, Percutaneous closure of the left atrial appendage versus warfarin therapy for prevention of stroke in patients with atrial fibrillation: a randomized non-inferiority trial, Lancet 2009;374:534-42.

The WATCHMAN® LAA Closure Technology is CE Marked and is currently available For Investigational Use Only in the United States.