Under an American Heart Association grant, physicians at several Strategically Focused Research Network institutions are implanting the newly redesigned Watchman FLX device in patients with atrial fibrillation (AFib) who can’t take long-term anticoagulants.¹ Results of this trial will help formulate best practices for closing off the left atrial appendage (LAA) to eradicate the leading cause of stroke in these patients.

“Ablation, followed by lifelong anticoagulant therapy, was once the expectation for most patients. But many have bleeding issues, are intolerant to the drug, can’t afford it or can’t maintain their Coumadin levels in a safe range,” said Christopher Ellis, M.D., director of the Left Atrial Appendage Closure Program at Vanderbilt University Medical Center. “Now there are not only better drug options, but there are minimally invasive procedures, and we are testing all of of these—the Lariat procedure and the Amulet, Watchman and Watchman FLX devices—as part of our current research.”

“For people with challenging anatomies, the seal on the new device is a significant improvement over the old Watchman.”

Ellis and his team recently implanted the new Watchman FLX device in 41 patients. Using transesophageal echocardiography (TEE) to study 45-day outcomes, they looked for evidence of thrombus, integrity of the implant (stability and absence of leakage) and endothelialization over the device. “For people with challenging anatomies, the seal on the new device is a significant improvement over the old Watchman,” said Ellis. “The imaging looks promising.”

Recently, Boston Scientific reduced the size of the metal hub on the Watchman FLX to further discourage thrombus formation around the hardware. Thrombus formation ceases to be a concern once endothelialization occurs, with a translucent cap forming over the top of the device.

©2018 Boston Scientific Corporation or its affiliates. All rights reserved. The WATCHMAN FLX™ Left Atrial Appendage Closure Device is an investigational device and is not available for sale in the U.S.

Rising Incidence and High Stakes

About 90 percent of clots that originate in the heart form in the LAA. “When a clot forms here, it’s usually not a small one. If a stroke follows, the result is often permanent and severe disability,” Ellis said. While blood thinners have high efficacy in preventing clot formation, stroke can still occur, even when the patient is medication compliant.

The bigger risk is borne by those who can’t or don’t take blood thinners. “About 50 percent of patients with AFib don’t take their blood thinner, don’t take it as instructed or are intolerant to it. That’s about a million people out there in the U.S. alone who are living with a very high risk for stroke,” Ellis said.

Flexibility Is a Design Advantage

Ellis, who has performed over 500 LAA closures, is pleased with how the Watchman FLX design changes impact implantation. “For the 16 percent of patients who have ‘chicken wing’ morphology [an early and severe bend in the ostial neck], the flexibility of the Watchman FLX is needed to get around the bend and place the device,” he said.

It also allows repeat capture and recapture for improved implanter control. “You can push it in and pull it out multiple times. I can also squeeze it into a spot where I could not have fit the old device, and I don’t have to get as deep into the appendage to deliver it.”

Broadening the Field of Candidates

“My experience is that the Watchman FLX is one of the safer implants and will provide protection to a broader population of patients,” Ellis said. He expects that by 2022 all four of the procedures under review will be made available. “We are delivering prophylaxis and stroke prevention, but I want to give this to patients with almost zero risk involved. We’re getting there.”

Patients who are able to take anticoagulants long-term may be the next candidates for a Watchman FLX implant and the other minimally invasive procedures. “For many patients, the greater peace of mind when they don’t have to worry about bleeding risks is immeasurable,” Ellis said.

About the Expert

Christopher Ellis, M.D.

Christopher R. Ellis, M.D., is an associate professor of medicine and director of the Left Atrial Appendage Closure Program at Vanderbilt University Medical Center. His clinical practice and research interests focus on electrophysiology, ablation, atrial fibrillation and other arrhythmia.

FOOTNOTES

All patients receiving the implant were contraindicated for long-term anticoagulant therapy, but eligibility requirements included the ability to tolerate short-term use of anticoagulants following the implant. The primary endpoint of    the trial will be patency of the closure as determined through a TEE one year from the procedure, and the absence of intervening events. At that point, outcomes will also be compared with those of patients who only took blood thinners.