Five-year Follow-up Data Demonstrate the WATCHMAN™ Left Atrial Appendage Closure Device Provides Stroke Risk Reduction Comparable to Warfarin Therapy
Late-breaking Clinical Trial Data Presented at TCT 2017 with Simultaneous Publication in the Journal of the American College of Cardiology

DENVER and MARLBOROUGH, Mass., Nov. 2, 2017 /PRNewswire/ -- Boston Scientific (NYSE: BSX) announced final five-year outcomes data from the PREVAIL study of the WATCHMAN™ Left Atrial Appendage Closure (LAAC) Device today during a late-breaking clinical trial session at the 29th Transcatheter Cardiovascular Therapeutics (TCT), the annual scientific symposium of the Cardiovascular Research Foundation, in Denver. The PREVAIL data, combined with final five-year outcomes from the PROTECT-AF clinical trial, demonstrated the WATCHMAN device continues to be a safe and effective alternative to long-term warfarin therapy offering comparable stroke risk reduction for patients with non-valvular atrial fibrillation (AF). The study was also published online today in the Journal of the American College of Cardiology 

In the PREVAIL and PROTECT-AF randomized clinical trials, LAAC with the WATCHMAN device was compared to warfarin for stroke prevention in high-risk patients with non-valvular AF. Upon completion of five-year follow up in both trials, study authors conducted a meta-analysis combining all data from the 1,114 randomized patients for a total of 4,343 patient-years. In addition to stroke prevention comparable to warfarin, the analysis concluded the WATCHMAN device also effectively reduced non-procedure related major bleeding, disabling or fatal stroke, and mortality. 

"With complete five-year follow up in two randomized clinical trials, left atrial appendage closure with the WATCHMAN device continues to demonstrate statistically significant reductions in death," said Vivek Reddy, M.D., principal investigator and director of Cardiac Arrhythmia Services for The Mount Sinai Hospital and the Mount Sinai Health System. "Importantly, the data further prove the WATCHMAN device is a safe and effective therapeutic alternative for stroke prevention in appropriate patients, enabling them to stop taking warfarin."

The comprehensive analysis confirmed a 55% reduction in disabling or fatal stroke, largely driven by an 80% statistically significant reduction in hemorrhagic stroke. Further, the combined data demonstrated a 52% decrease in non-procedure related major bleeding and 27% reduction in all-cause mortality when compared to long-term warfarin therapy.

"The data presented today lend additional credence to the long-term safety and efficacy for the WATCHMAN device," said Kenneth Stein, M.D., senior vice president and chief medical officer, Rhythm Management and Global Health Policy, Boston Scientific. "The totality of the data from both randomized trials and observational studies convincingly demonstrates ischemic stroke reduction similar to that observed with warfarin, when accounting for differences in CHA2DS2-VASc score."

The WATCHMAN device continues to be observed in post-market studies, including the national LAAO Registry™ sponsored by the American College of Cardiology. The registry will capture post-approval data on left atrial appendage occlusion procedures, as outlined as a condition of coverage by the Centers for Medicare and Medicaid Services in the LAAC National Coverage Determination.

For more information on the WATCHMAN device, visit

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