Device Profile: The Watchman Device

Called a “replacement for blood thinners,” what is the Watchman device and how does it work?

The Watchman is a permanent implant placed in the left atrial appendage of a patient’s heart. After experiencing atrial fibrillation, the left atrial appendage is where thrombosis is most likely to develop in the heart. The device is fitted with a 160-micron membrane PET cap to stop clots that may form and break away. Designed for non-valvular atrial fibrillation patients, the Watchman prevents blood clots from entering into the bloodstream and potentially causing a stroke.

According to Boston Scientific, the device’s parent company, the implant is good for patients who experience trouble with their anticoagulants, such as those who have compliance issues, have trouble stabilizing their INR, or have a high risk for bleeding.

The FDA reports that the Watchman was tested in four clinical studies.

“Two clinical studies suggested that warfarin was better than the WATCHMAN in preventing strokes caused by a blocked blood vessel in the brain,” reports the FDA. “However, the number of strokes caused by bleeding in the brain was lower in the WATCHMAN patients compared to the warfarin patients.”

In terms of bleeding risk, the FDA reports, “The overall rate of serious bleeding was similar in the WATCHMAN and warfarin patients. Within several months after the device was implanted, the rate of serious bleeding was higher in the WATCHMAN patients as compared to warfarin patients. However, beginning six months after the device implant procedure, the rate of serious bleeding was lower in WATCHMAN patients.”


The Watchman device is implanted through the use of a delivery catheter. It is inserted in a vein in the leg and then pushed through the bloodstream. It eventually enters the right atrium and, through a hole in the atrial septum, is placed into the left atrial appendage.

For a closer look at the Watchman’s implantation, see Boston Scientific Cardiology’s video below:


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