The WATCHMAN FLX™ left atrial appendage closure (LAAC) device is the first FDA-approved device indicated to reduce the risk of stroke in NVAF patients. Credit: Boston Scientific Corporation.
The WATCHMAN FLX LAAC device features a next-generation fully rounded frame design. Credit: Boston Scientific Corporation.
The PINNACLE FLX study evaluated the performance of the WATCHMAN FLX device. Credit: Boston Scientific Corporation.

The WATCHMAN FLX™ is the first US Food and Drug Administration (FDA) approved left atrial appendage closure (LAAC) device developed by Boston Scientific Corporation.

The device is indicated to minimise the risk of stroke in non-valvular atrial fibrillation (NVAF) patients who require an alternative to oral anticoagulation therapy by permanent closure of the left atrial appendage. The left atrial appendage is a region in the heart where stroke-causing blood clots typically generate in NVAF patients.

Boston Scientific received the European CE Mark for the WATCHMAN FLX LAAC device in November 2015 while its next-generation device received the CE Mark in March 2019.

The FDA approved the device in July 2020 and the company will soon begin the limited launch of the product in the US. The device has been implanted in more than 100,000 people worldwide by May 2020.

Details of WATCHMAN FLX device

The WATCHMAN FLX is a next-generation LAAC device with a fully rounded frame design for implantation in patients in a one-time procedure.

It is the first LAAC device that can be completely grasped, rearranged and redeployed for accurate positioning. The design of the new frame facilitates superior device engagement for long-term stability and ensures a rapid, and comprehensive seal. It allows the physicians to easily and safely reach the device within the left atrial appendage for manoeuvring during the procedure.

The device employs new stroke risk-reducing technology to improve its performance and safety during the procedure, as well as treat a range of patients with NVAF.

The WATCHMAN FLX LAAC system acts as a one-time solution to blood thinners in patients with NVAF to minimise stroke risk.

The device is available in multiple size options than the previous generation device to suit varying anatomies.

WATCHMAN FLX device functionality

Atrial fibrillation (AF) affects the heart’s capacity to pump blood naturally, which can lead to the accumulation of blood in the left atrial appendage (LAA) of the heart.

The blood accumulation in LAA increases the risk of blood clot formation in the area, which can gradually migrate to other parts of the body and cut off the blood supply to the brain, causing a stroke.

More than 90% of stroke-causing clots in the heart are formed in the LAA of patients with NVAF and closure of the LAA is a successful procedure to minimise the risk of stroke in those patients.

The WATCHMAN FLX device is implanted via a transfemoral approach, using a minimally invasive procedure. It is designed to completely close the LAA, which can allow many patients to avoid long-term use of blood thinners while minimising their associated bleeding risk and lifestyle challenges.

PINNACLE FLX clinical study

The PINNACLE FLX pivotal trial determined the procedural safety and closure efficacy of WATCHMAN FLX LAAC system.

It was a single-arm, non-randomised trial that evaluated the device as a substitute for oral anticoagulation therapy, including non-vitamin K antagonist oral anticoagulants (NOACs), for stroke risk reduction in patients with NVAF.

The trial was carried out on 400 patients at 29 locations across the US.

The rate of successful LAA closure was the primary endpoint of the trial, which was defined as any peri-device flow less than or equal to 5mm at 12 months shown by transesophageal echo (TEE) test.

The WATCHMAN FLX device achieved a low rate (0.5%) of adverse events at seven days after the procedure and higher rate (100%) of effective LAA closure at 12 months.

The data also showed a high (98.8%) implant success rate for the device.