This article has been updated to include comments from Boston Scientific.
A recent review of FDA files has found nearly 3,000 adverse events related to Boston Scientific’s (NYSE:BSX) Watchman device.
The Watchman left atrial appendage closure device, approved by the agency in March 2015, is designed to prevent blood clots that form in the heart’s left atrial appendage from reaching the brain. Boston Scientific markets it as an alternative to blood-thinning drugs such as warfarin. More than 100,00 Watchman devices have been implanted worldwide, according to the website Watchman.com.
The review of the FDA’s Manufacturer and User Facility Device Experience (MAUDE) database found 2,974 Watchman-related adverse events had occurred between April 2015 and December 2018. They included:
- About 211 deaths.
- 42% pericardial effusion (fluid around the heart).
- 11% thrombus.
- 5.7% stroke.
- 5% device embolization.
The percentages of reported events rose steadily as well, with 10.2% in 2015, 20.8% in 2016, 34.4% in 2017 and 34.6% in 2018. Dr. Swaiman Singh, a cardiologist with Newark (N.J.) Beth Israel Medical Center, reported the findings at the recent TCT 2019 conference in San Francisco. Singh told attendees that rather than shying away from the Watchman, cardiologists should use the information to better manage these issues and improve patient outcomes, according to a report by TCTMD.
Management strategies in patients with pericardial effusion included no intervention in 32% (n = 400), pericardiocentesis in 62% (n = 777), pericardial window in 1.5% (n = 19), and open-heart surgery in 16.9% (n = 213). A total of 64 of these patients required intensive unit level of care, according to the study, which was published in the Journal of the American College of Cardiology.
The high rate of pericardiocentesis suggests “that most of these pericardial effusions occurred as macro-perforations,” Singh said, according to TCTMD. Experience in transseptal puncture or working with a colleague who has those skills is key to preventing this complication, he added.
“If you’re careful in reviewing what has been going on, and you’re careful in your technique, I think most of the adverse events that we see with Watchman can be prevented,” Singh told TCTMD.
Boston Scientific told MassDevice in an email that the rate of adverse events has continued to improve since the initial clinical trials of the Watchman device.
“We aim to have the lowest possible rate of adverse events associated with the device,” the company added. “Post-approval studies/surveillance and real-world outcomes continue to demonstrate the Watchman device is a safe, efficacious alternative option to long-term warfarin therapy for patients with non-valvular atrial fibrillation who are seeking another treatment to reduce their risk of stroke. Mortality rates reported in the post-market experience for the Watchman device are low, in line with clinical trial results and consistent with other left-sided heart procedures. Further, our robust training program and diligent clinical support are designed to support these safe outcomes.”
A Philadelphia cardiologist recently wrote a newspaper column questioning the efficacy and cost of the Watchman.