An observational, prospective study found that there was a 98.8 percent technical success rate with the investigational Amplatzer Amulet LAA Occluder in patients with non-valvular atrial fibrillation.

Within seven days of the procedure, acute device- or procedure-related major adverse events occurred in 2.7 percent of the patients.

Lead researcher David Hildick-Smith, MD, presented the findings Nov. 2 in a late-breaking clinical trials session at the Transcatheter Cardiovascular Therapeutics scientific symposium in Washington, D.C. St. Jude Medical, which manufactures the Amplatzer, funded the study.

The Amplatzer Amulet LAA Occluder, which is not yet FDA-approved, is a percutaneous transcatheter left atrial appendage (LAA) closure device intended for stroke prevention in patients with non-valvular atrial fibrillation. St. Jude Medical announced Sept. 1 that it had launched the Amplatzer Amulet investigational device exemption trial to assess closure of the LAA in patients with non-valvular atrial fibrillation.

So far, the Watchman (Boston Scientific) is the only FDA-approved LAA occlusion device. The Centers for Medicare & Medicaid Services released a national coverage determination for percutaneous LAA closure for non-valvular atrial fibrillation in February that required patients undergoing LAA closure to be included in a national prospective registry.

In this trial, known as the Amulet Observational Study, the researchers enrolled 1,073 patients with non-valvular atrial fibrillation between June 2015 and September 2016 at 64 sites in 18 countries in Europe, the Middle East, Asia, Australia and South America. Of the patients, 85 percent had contraindications to anticoagulation.

The operators had a technical success rate of 98.8 percent and a closure rate of 99 percent at one- to three-month follow-up visits. Of the 13 patients who did not have a successful implant, seven had thrombus in the LAA, so the physicians did not attempt an implant in those seven patients. The researchers defined closure as absence of flow or flow or less than 3 mm jet into the LAA.

Within seven days of the procedure, the major adverse event rates were 0.3 percent for ischemic stroke, 0.5 percent for pericardial effusion requiring intervention, 0.1 percent for embolization and 0.9 percent for bleeding. There were also three deaths within seven days, including two of which were procedure- or device-related. The other death was not device-related.

“These results indicate that the Amplatzer Amulet is safe and associated with low rates of peri-procedural and early adverse events, as well as demonstrating high closure rates,” Hildick-Smith said in a news release. “In addition, antiplatelet therapy appears to be an effective treatment strategy post-implantation in the short-term. Additional long-term data is necessary to confirm these promising early findings.”