TCT: Amulet LAA Occluder Hot on the Heels of Watchman

WASHINGTON -- The Amplatzer Amulet left atrial appendage (LAA) occlusion device exhibited high closure rates and was tied to few early adverse events, the lead investigator of the AMULET study reported here.

There was a 99% rate of full LAA closure at Amulet implantation and up to 3 months later on transesophageal echocardiography (TEE), said David Hildick-Smith, MD, of Brighton and Sussex University Hospitals in England, presenting his late-breaking trial at the annual Transcatheter Cardiovascular Therapeutics (TCT) meeting.

After placement of the Amulet, the proportion of patients on non-vitamin K antagonist oral anticoagulants fell from 18% to 8.4% on follow-up. Three-quarters were on single or dual antiplatelet agents.

Meanwhile, there was a relatively low 2.7% incidence of adverse events, including the following:

• Death 0.3%
• Stroke 0.3%
• Pericardial effusion 0.5%
• Bleeding 0.9%

"Antiplatelet therapy is appears to be a reasonable treatment strategy post-implantation in the short-term," Hildick-Smith suggested.

The FDA approved another LAA closure device, the Watchman, in 2015, after previous rejections over questions of its efficacy. Confusion followed when the Centers for Medicare & Medicaid Services restricted coverage to patients contraindicated for warfarin (Coumadin); that limitation was eased earlier this year.

"For a while it was hurtful for hospitals to put them in," recalled D. Christopher Metzger, MD, of Wellmont CVA Heart Institute in Kingsport, Tenn., at a TCT press conference, yet "patients in general don't want to take anticoagulants if they don't have to."

He called LAA occlusion technology "exciting," although commented that it should be performed by centers of excellence for now.

The Amulet data showed similar rates of implant success, LAA closure, and device-related complications with the Watchman's EWOLUTION study, according to Hildick-Smith.

AMULET was a multicenter, prospective registry of 711 patients who got the device and completed follow-up. Operators achieved an implant success rate of 98.8%.

A prior history of major bleeding was reported in 72.5% of patients before the intervention. In addition, the average CHA₂DS₂-VASc score was 4.2; HAS-BLED scores averaged 3.3.

The Amplatzer Amulet was implanted as a means of stroke prevention in patients with atrial fibrillation. Accordingly, most patients (85%) got the device because of a contraindication to oral anticoagulation, while 9% did so because they experienced ischemic stroke despite oral anticoagulation; another 5% personally opted for the intervention.

The Amplatzer Amulet is distinct from the Amplatzer PFO Occluder, which was recently given regulatory clearance by the FDA for patients with cryptogenic stroke. Amulet is currently approved in Europe but remains investigational in the U.S. Manufacturer St. Jude Medical said it has begun a multinational trial including up to 100 U.S. sites.

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