Boston Scientific Presents Imaging Findings From Premarket WATCHMAN FLX Pro CT Pilot Study

November 6, 2023—Boston Scientific recently announced results from the 25-patient prospective, single-center premarket WATCHMAN FLX Pro CT pilot study of the company’s Watchman FLX Pro left atrial appendage closure (LAAC) device.

The study, which was conducted at Aarhus University Hospital in Aarhus, Denmark, used multiple imaging modalities to assess tissue coverage around the Watchman FLX Pro LAAC device at 45 days postprocedure and the relationship, if any, to clinical outcomes in patients with nonvalvular atrial fibrillation receiving the device to reduce their risk of stroke. Jens Erik Nielsen-Kudsk, MD, presented the findings in a featured clinical science session at TCT 2023, the 35th annual Transcatheter Cardiovascular Therapeutics scientific symposium held October 23-26 in San Francisco, California.

According to Boston Scientific, the study was the first to image at 14 days using transesophageal echocardiogram (TEE), CT, and optional magnetic resonance imaging (MRI), which allowed a never-before-seen window into the healing process of an LAAC device at this point. The study leveraged the Hemocoat polymer coating on the Watchman FLX Pro LAAC device, which is designed to reduce device-related thrombus (DRT) and enable faster, controlled healing and endothelization of the device surface.

As outlined by Boston Scientific, the following findings were presented at TCT:

• Early healing—or tissue growth at 14 days—was observed in nearly all patients upon serial imaging, which is consistent with the preclinical work with the Watchman FLX Pro device.
• At 14 days, one patient at high risk for DRT demonstrated a suspected thrombus on TEE and CT; however, this resolved by 45 days under continued aspirin monotherapy.
• By 45 days, with no additional medical therapy beyond single antiplatelet therapy, site-reported data demonstrated that all patients exhibited signs of normal healing with no DRT. Follow-up serial imaging at 3-months was concluded to be consistent with normal healing.

FDA approval of the Watchman FLX Pro was announced on September 6, 2023. Boston Scientific advised it will continue assessing clinical outcomes for the Watchman FLX Pro device in a larger patient set in the HEAL-LAA postmarket study of 1,000 patients.