Boston Scientific’s Watchman LAAC device found to reduce stroke risk

13 May 2012 (Last Updated May 13th, 2012 18:30)

Boston Scientific's Watchman left atrial appendage closure (LAAC) device has reduced the risk of ischemic stroke by 75% in patients with atrial fibrillation who have a contraindication to oral anticoagulants, such as warfarin, within a multicentre study.

Boston Scientific

Boston Scientific's Watchman left atrial appendage closure (LAAC) device has reduced the risk of ischemic stroke by 75% in patients with atrial fibrillation who have a contraindication to oral anticoagulants, such as warfarin, within a multicentre study.

The CE-marked Watchman LAAC device is a self-expanding nitinol frame consisting of an access sheath and delivery system that allows device placement in the LAA via the femoral vein and inter-atrial septum crossing into the left atrium.

The Watchman device is designed to close the LAA, preventing clots forming within the appendage and being dislodged into the bloodstream, where they can potentially cause a stroke.

"Watchman is the most studied LAA closure device, with more than 2,000 patients enrolled in prospective studies."

The prospective multicentre ASA Plavix (ASAP) study implanted 150 patients with the Watchman LAAC device and treated them with dual antiplatelet therapy for six months post-procedure.

Patients implanted with the Watchman device showed an ischemic stroke rate of 1.7% a year, a 75% reduction in stroke risk from the predicted stroke rate measured using the CHADS2 risk stratification score.

Boston Scientific global chief medical officer Keith Dawkins said Watchman is the most studied LAA closure device, with more than 2,000 patients enrolled in prospective studies and nearly 4,000 patient-years of follow-up.

"This novel device has been well received in more than 30 countries, where it offers a safe and effective alternative to long-term treatment with oral anticoagulants," Dawkins added.

Mount Sinai Medical Center, US, director and coordinating investigator of the study Vivek Reddy said findings from the ASAP study are promising in that closure of the LAA with the Watchman device produced a considerable reduction in the expected ischemic stroke rate.

"These results are very impressive and show potential for an effective device-based solution for higher-risk patients with limited pharmacologic options to reduce their risk of stroke," Reddy added.

Currently, Boston is enrolling US patients in the Prevail study, a confirmatory study designed to gain US Food and Drug Administration approval for the Watchman LAAC device.


Image: Boston Scientific's Corporate Headquarters in Natick, Massachusetts, US. Photo courtesy of: Boston Scientific.