Boston Scientific suspended the sales of its second-generation Watchman FLX in Europe because of embolism concerns. Patients who received the device showed unexpectedly high embolic rates.

The Watchman FLX Left Atrial Appendage Closure (LAAC) Device was sold in Europe last November. Out of 207 implants, six reports (2.9 percent) showed high embolism rates post embedding. The complication resulted in one death that was linked to postoperative infection after the device was removed in a percutaneous medical procedure.

Boston Scientific said it is investigating the matter and looking for the cause of the higher-than-expected embolism rates, which could be found in the implant technique used and the physician's training.

The Watchman FLX LAAC Device provides a new method for reduction of stroke risk. It is designed for patients with non-valvular atrial fibrillation (irregular heartbeat) who are looking for other options for long-term anti-blood clotting treatment.

The implantation device seals off the left atrial appendage where the blood can potentially pool and clot. The device allows patients to stop taking the blood thinner drug warfarin.

In the United States, the Food and Drug Administration (FDA) approved the first-generation Watchman LAAC Device in 2015. According to, clinical trials for the FLX version are planned but they have yet to enroll study participants.

"This a device that is currently not available in the United States, so I don't think there should be any fear for any of the patients who are receiving the current device in the United States," said Dr. Roxana Mehran from the Icahn School of Medicine about the second-generation Watchman device during the 2016 Scientific Sessions of the American College of Cardiology.

Mehran added that these things happen when a device has new versions and expressed confidence that the company will do the necessary actions needed for the patients in Europe who were affected by the high embolism rates.

According to the U.S. Heart Rhythm Society, there are more than 3 million American patients who suffer from atrial fibrillation, which is the most common form of arrhythmia. These patients have higher chances (five times) of developing a stroke compared to people without the ailment.

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