Continuing to build a portfolio of transcatheter structural heart technology, Boston Scientific today signed a definitive merger agreement to acquire Atritech Inc. Atritech developed the Watchman device, which is designed to close the left atrial appendage (LAA) in patients with atrial fibrillation who are at risk for ischemic stroke.
The agreement calls for an upfront payment of $100 million plus additional potential payments of up to $275 million upon achievement of specified regulatory and revenue-based milestones through 2015. The closing transaction is expected to be complete in the first quarter of 2011.
The Watchman LAA closure technology is the first device proved in a randomized clinical trial to offer an alternative to anticoagulant drugs, which are associated with an increased risk of bleeding. Patients with atrial fibrillation are prone to developing blood clots in LAA. If these clots dislodge and enter the bloodstream they may block circulation to the brain, resulting in a stroke. The device closes the appendage, thereby preventing clots from being dislodged into the circulation.
Atritech has completed PROTECT-AF, an 800-patient randomized clinical trial of the Watchman, which 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 approval. The Watchman device is CE marked and was commercialized outside the United States in 2009.
"The acquisition of Atritech reinforces Boston Scientific's continued commitment to providing the broadest portfolio of less-invasive devices across the continuum of cardiovascular care," said Hank Kucheman, executive vice president and group president, cardiology, rhythm and vascular for Boston Scientific. "The Watchman device is implanted by both electrophysiologists and structural heart-focused interventional cardiologists. We will leverage expertise from our electrophysiology and interventional cardiology sales forces to drive commercialization of the Watchman device. Atritech will significantly strengthen our product offerings for patients with atrial fibrillation."
"Both Atritech and Boston Scientific believe that the Watchman device offers the best alternative to oral anticoagulation medication for patients who suffer from atrial fibrillation and are at high risk for stroke," said Jim Bullock, president and CEO of Atritech. "We look forward to working with Boston Scientific to expand the left atrial appendage closure market and to bring this technology to more patients worldwide."
"This is an important acquisition in the fast-growing areas of atrial fibrillation and structural heart therapy, both of which are among our priority growth initiatives," said Ray Elliott, president and CEO of Boston Scientific. "Left atrial appendage closure represents a significant growth opportunity for Boston Scientific. We are impressed by Atritech's technology, and we have the sales and marketing infrastructure to help realize the full potential of the Watchman device. Together with other recent acquisitions, we expect Atritech to play a key role in the realignment of our portfolio."
For more information: www.bostonscientific.com, www.atritech.net
November 14, 2025 
