Comparison of Amulet vs Watchman/FLX Devices in Patients Undergoing Left Atrial Appendage Closure - SWISS-APERO

Oct 24, 2023
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Author/Summarized by Author:
Dharam J. Kumbhani, MD, SM, FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC; Kim A. Eagle, MD, MACC
Trial Sponsor:
University Hospital of Bern, Switzerland; Abbott
Date Presented:
10/24/2023
Date Published:
10/24/2023
Date Updated:
10/24/2023
Original Posted Date:
11/06/2021
References

Contribution To Literature:

Highlighted text has been updated as of October 24, 2023.

The SWISS-APERO trial showed that Amulet is not superior to Watchman for LAA patency (assessed by CCTA) at 45 days among patients undergoing percutaneous LAAC.

Description:

The goal of the trial was to demonstrate the superiority of Amulet compared with Watchman FLX for patients undergoing left atrial appendage closure (LAAC).

Study Design

All patients were randomized in a 1:1 open-label fashion to LAAC with either Amulet (n = 111) or Watchman (n = 110).

Patients randomized to the Watchman group before October 2019 received Watchman 2.5 (22.7%), whereas all patients randomized to the Watchman group after October 2019, received Watchman FLX.

  • Total number screened: 423
  • Total number of enrollees: 221
  • Duration of follow-up: 45 days
  • Mean patient age: 76.9 years
  • Percentage female: 29.4%

Inclusion criteria:

  • Nonvalvular atrial fibrillation
  • Clinical indication for LAAC
  • Age ≥18 years
  • CHA2DS2-VASc score ≥2 and either HAS-BLED score ≥3 or presence of high bleeding risk features
  • LAA anatomy suitable for both devices

Exclusion criteria:

  • LAA thrombus
  • Creatinine clearance <30 ml/min
  • Enrollment in another cardiovascular device or investigational drug trial

Other salient features/characteristics:

  • HAS-BLED score: 3.2
  • Need for dual antiplatelet therapy due to coronary artery disease/stenting: 13%
  • On oral anticoagulation monotherapy: 36%

Principal Findings:

The primary outcome, LAA patency on coronary computed tomography angiography (CCTA) at 45 days for Amulet vs. Watchman FLX, was: 67.6% vs. 70% (p = 0.71).

  • Intradevice leak: 44.8% vs. 23% (p = 0.001)
  • Mixed leaks: 3.8% vs. 14% (p = 0.01)

Secondary outcomes for Amulet vs. Watchman FLX:

  • Transesophageal echocardiography (TEE)-defined peridevice leak (>5 mm): 13.7% vs. 27.5% (p = 0.02)
  • Definite device-related thrombosis: 0.9% vs. 3.0% (p = 0.29); definite or probable device-related thrombosis: 3.7% vs. 9.9% (p = 0.076)
  • Major procedure-related complications: 9.0% vs. 2.7% (p = 0.047), major bleeding: 7.2% vs. 1.8% (p = 0.05), clinically relevant pericardial effusion: 3.6% vs. 0% (p = 0.12)
  • Cardiovascular disease/stroke/systemic embolism: 2.7% vs. 4.5%
  • 45-day death: 1.8% vs. 0% (p = 0.5; all periprocedural)

13-month outcomes for Amulet vs. Watchman FLX:

  • Patent appendage rate: 53.6% vs. 48.8% (p = 0.54). 30.5% of patent appendages at 45 days resolved by 13 months; 13.2% new-onset patent appendages between 45 days and 13 months
  • Definite or possible device-related thrombus (DRT): 2.4% vs. 3.8% (p = 0.61)
  • Composite of cardiovascular death/stroke/systemic embolism: 9.5% vs. 10.2% (p = 0.83)
  • Any bleeding: 40.8% vs. 31.4% (p = 0.098)

Interpretation:

The results of this trial indicate that Amulet is not superior to Watchman for LAA patency (assessed by CCTA) at 45 days among patients undergoing percutaneous LAAC. Peridevice leaks were higher with Watchman on CTA and TEE, while intradevice leaks were higher with Amulet on CTA, although some of these could improve over time as the device endothelializes. Use of the Amulet device resulted in higher procedural complications, including major bleeding and pericardial effusions. A similar higher complication risk was noted in the Amulet IDE trial. Results are interesting and add to the available literature comparing the two devices for percutaneous LAAC.

At 13 months, LAA patency rates on CCTA were high but similar between the two devices, while DRT rates were low but also similar. Nearly two thirds of patients with patent appendage on CT still had evidence of patency at 13 months, while 13% developed new patency. The clinical significance of these findings is unclear and will need to be further ascertained in future studies.

References:

Galea R, Meneveau N, De Marco F, et al. One-Year Outcomes After Amulet or Watchman Device for Percutaneous Left Atrial Appendage Closure: A Pre-Specified Analysis of the SWISS-APERO Randomized Clinical Trial. Circulation 2023;Oct 24:[Epub ahead of print].

Presented by Dr. Roberto Galea at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2023), San Francisco, CA, October 24, 2023.

Galea R, De Marco F, Meneveau N, et al. Amulet or Watchman Device for Percutaneous Left Atrial Appendage Closure: Primary Results of the SWISS-APERO Randomized Clinical Trial. Circulation 2022;145:724-38.

Presented by Dr. Roberto Galea at the Transcatheter Cardiovascular Therapeutics (TCT) Conference, Orlando, FL, November 6, 2021.

Clinical Topics: Arrhythmias and Clinical EP, Atrial Fibrillation/Supraventricular Arrhythmias, Anticoagulation Management and Atrial Fibrillation, Invasive Cardiovascular Angiography and Intervention

Keywords: Anticoagulation Management, Atrial Fibrillation, Peripheral Intervention, TCT23, Transcatheter Cardiovascular Therapeutics


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