Key Points
- The AMULET Left Atrial Appendage Occluder was shown to be noninferior to the Watchman device for patients with atrial fibrillation; results of the AMULET-IDE trial were presented at the European Society of Cardiology In August, 2021.
- Primary AMULET IDE results showed not only safety at 12 months and effectiveness at 18 months, but closure at 45 days, defined as peridevice leak of <5 mm.
- 12 month follow up with core-lab echocardiographic analysis of perivalvular leak, fewer patients with the AMULET device had moderate peridevice leak when compared to the Watchman device. Long term implications and consequences of peridevice leak are yet unknown.
The AMULET left atrial appendage occlude is a newly FDA approved competitor to the Watchman device. In the landmark AMULET IDE trial, presented at ESC 2021 earlier this year, the device was found to be noninferior to Watchman with respect to safety and effectiveness. At a late-breaking clinical trial session at the 33rd annual TCT conference in Orlando, Florida, Dr. Dr. Dhanunjaya Lakkireddy, MD from the Kansas City Heart Rhythm Institute at HCA Midwest Health presented the one-year follow up data on peridevice leak (PDL) for both devices used in the AMULET IDE trial.
In the Amulet IDE open-label, randomized clinical trial, 1,878 patients (1,598 from 78 U.S. centers, and 280 from 30 centers outside the US) were randomized 1:1 to receive either the novel Amulet device, or the first-generation Watchman device. Eligibility criteria included non-valvular AF, high stroke risk (CHA2DS2-VASc score ≥3), being suitable for short-term warfarin but with an appropriate rationale to seek an alternative to anticoagulation therapy, and being suitable for LAA closure. The primary non-inferiority composite endpoint included mechanism of action (residual LAA jet around the device ≤5mm at 45 days), safety (procedure-related complications, major bleeding or all-cause death at 12 months), and effectiveness (ischemic stroke or systemic embolism at 18 months). Secondary endpoints included testing for superiority for each of the individual endpoints, as well as for major bleeding. Importantly, per protocol, patients treated with first-generation Watchman devices were mandated to remain on aspirin plus warfarin, while patients treated with Amulet could be treated with aspirin + clopidogrel or aspirin + direct oral anticoagulant.
Longitudinal data were assessed at 45 days and 12 months by core-lab analysis. PDL was graded as none (0 mm), mild (0-3 mm), moderate (3-5 mm), and severe (>5mm). At 45 days, fewer patients who received the AMULET device were left with moderate or greater PDL when compared to Watchman (11% vs. 26%, p<0.001). This trend held true at 12 months: 9% vs. 22%, p<0.001). The authors therefore suggested that the AMULET device is superior to the Watchman device when it comes to device leak. The implications and impact of peridevice leak, however, are yet to be understood. Long-term data will help shed light on the importance of these findings.