Boston Scientific has completed its acquisition of Atritech. The completion of the transaction follows the signing of a definitive merger agreement announced on Jan. 19, 2011.
Atritech's Watchman Left Atrial Appendage Closure Technology gives Boston Scientific a product designed for atrial fibrillation patients with high stroke risk. Atrial fibrillation patients are prone to developing blood clots in the left atrial appendage (LAA) that can dislodge and block circulation to the brain, resulting in a stroke. The device is designed to close the LAA, thereby preventing clots from being dislodged into circulation.
Atritech has completed PROTECT-AF, an 800-patient randomized clinical trial that demonstrated a 38 percent relative risk reduction for stroke, cardiovascular death and systemic embolism compared to long-term warfarin therapy. Atritech is currently enrolling patients in the PREVAIL study, a confirmatory study designed to gain U.S. Food and Drug Administration (FDA) approval. The Watchman device is CE Marked and was commercialized outside the United States in 2009.
Under the acquisition agreement, Boston Scientific purchased all outstanding Atritech shares for a total of $100 million. Additional payments of up to $275 million are contingent upon achievement of specified regulatory and revenue-based criteria through 2015.
For more information: www.bostonscientific.com, www.atritech.net
October 26, 2026 
