WATCHMAN FLX device close up with decorative teal overlay


SEAL FLX is the first study that compares complete occlusion results of the WATCHMAN FLXTM device and the AmplatzerTM AmuletTM device exclusively, using cardiac computed tomography (CT)1.

Study Design

  • Single-center, retrospective study of LAAO implantation at Aarhus 
 University Hospital (Denmark) between 2018-2020.
    1st cohort: Amplatzer Amulet (n=150) 2018 – 2019
    2nd cohort: WATCHMAN FLX (n=150) 2019 – 2020
  • Cardiac CT was performed 8 weeks after LAAO
Primary Outcome Complete Seal* Based on CT Imaging

WATCHMAN FLX Demonstrated Statistically Superior Complete Occlusion* vs Amulet (p=0.001)

Complete Occlusion* at 8 Weeks (per CT)

Complete LAA Occlusion graph

Complete Occlusion* on CT Imaging1

More Leak Pathways with a Two-Component Device at 8 Weeks (per CT)

Peri-Device Leak
Peri Device Leak graph

Leak Measurements were Significantly Larger with Amulet than WATCHMAN FLX (p=0.008) at 8 Weeks (per CT)

Leak Size (mm2)
Peri Device Leak graph

WATCHMAN FLX’s One-Component Design Translates to Clear Sealing Advantages

Simplified Sizing


WATCHMAN FLX sizing icon

Single Landing Zone and Overlapping Treatment Ranges


Amplatzer Amulet sizing icon

Complicated, Mis-Matched Measurements

Simplified Placement


WATCHMAN FLX placement icon

Precision Placement Control


Amplatzer Amulet placement icon

Trade-off Between Disc and Lobe Placement

Simplified Assessment


WATCHMAN FLX assessment icon

Full Visibility


Amplatzer Amulet assessment icon

Hidden Leaks

WATCHMAN FLX: Trusted Safety. Proven Efficacy. No Compromises.

WATCHMAN FLX device with decorative teal overlay

1. Korsholm-K et al.; TCT 2021.
2. Lakkireddy, Amulet Tips and Tricks in Simple and Complex Anatomy, TVT 2018.
3. Saw, Cardiac CT angiography for device surveillance after endovascular left atrial appendage closure, European Heart Journal - Cardiovascular Imaging, Volume 16, Issue 11, November 2015, Pages 1198–1206,
* Complete LAA occlusion defined as no visible peri-device leak (PDL) and absence of contrast patency in the distal LAA (LAA/left atrium Hounsfield ratio <0.25)