3-Year Outcomes From the Amplatzer Amulet Left Atrial Appendage Occluder Randomized Controlled Trial (Amulet IDE)

Area of Science:

• Cardiology
• Medical Devices
• Clinical Trials

Background:

• The Amulet (Abbott) left atrial appendage occluder investigational device exemption trial is the largest randomized trial evaluating the safety and effectiveness of the Amulet left atrial appendage occluder compared with the Watchman 2.5 device (Boston Scientific) through 5 years.
• Atrial fibrillation necessitates stroke risk reduction strategies, often involving anticoagulation or left atrial appendage occlusion devices.

Purpose of the Study:

• To evaluate the device effect on 3-year outcomes in the Amulet investigational device exemption trial.
• To compare the safety and effectiveness of the Amulet left atrial appendage occluder versus the Watchman 2.5 device.

Main Methods:

• A total of 1,878 patients at 108 sites were randomized.
• Key clinical outcomes including composite ischemic stroke or systemic embolism (SE), composite all strokes/SE/cardiovascular (CV) death, major bleeding, and all-cause/CV death were reported through 3 years.

Main Results:

• A significantly higher percentage of patients were free of oral anticoagulation usage at 3 years with Amulet (96.2%) vs Watchman (92.5%) (P < 0.01).
• Clinical outcomes were comparable for the composite of ischemic stroke or SE (5.0% vs 4.6%; P = 0.69); composite of all strokes, SE, or CV death (11.1% vs 12.7%; P = 0.31); major bleeding (16.1% vs 14.7%; P = 0.46); all-cause death (14.6% vs 17.9%; P = 0.08); and CV death (6.6% vs 8.5%; P = 0.14) for Amulet and Watchman, respectively.
• Device factors (thrombus or peridevice leak ≥3 mm) preceded ischemic stroke events and CV deaths more frequently in Watchman compared with Amulet patients through 3 years.

Conclusions:

• The Amulet occluder demonstrated continued safety and effectiveness with over 96% free of oral anticoagulation usage through 3 years in a high-risk population compared to the Watchman device.
• Device factors such as thrombus or peridevice leak were less frequent with the Amulet compared to the Watchman device, potentially contributing to comparable clinical outcomes.