WATCHMAN FLX device close up with decorative teal overlay

Procedural and short-term follow-up outcomes of WATCHMAN FLX™ Device vs Amplatzer™ Amulet™ Occluder: a meta-analysis

Study design

  • Meta-analysis (published in Heart Rhythm) of 4186 patients from 21 studies (a meta-analysis is a statistical technique used to systematically combine data from a number of independent studies to develop a single conclusion that is statistically stronger than the analysis of any single study)
  • 3187 Amulet implants
  • 999 WATCHMAN FLX implants
  • No difference in TE risk between groups
  • CHA2DSC2-VASc: 4.3±1.5 for Amulet
  • CHA2DSC2-VASc 4.2±1.5 for WATCHMAN FLX
  • Data from a first imaging study performed within 3-month were used to assess the incidence of peri-device leaks >5mm and device-related thrombosis (DRT).

Safety endpoint

Safety endpoint was the occurrence of death, stroke, major bleeding, myocardial infarction, major vascular complications, device embolization, or pericardial effusion within 7 days post-procedure.

The largest comparison of peri-procedural success and short-term outcomes of LAAC devices, Amplatzer Amulet vs. WATCHMAN FLX reveals superior procedural safety, higher procedural success, and better LAA closure with WATCHMAN FLX.

WATCHMAN FLX device with decorative teal overlay

Key results


WATCHMAN FLX showed a significantly lower incidence of peri-procedural complications (p<0.01)

Adverse Events graph
  • WATCHMAN FLX  superior on primary safety endpoint (0.6% FLX vs 4.7% Amulet, p<0.01) 
  • WATCHMAN FLX  superior on overall pericardial effusion/tamponade (0.1% FLX vs 2.5% Amulet, p<0.01) 
  • WATCHMAN FLX  superior on clinically relevant pericardial effusion/tamponade (0.01% FLX vs 0.7% Amulet, p=0.01) 
  • WATCHMAN FLX  superior on peri-procedural major/intracranial bleeding (0.1% FLX vs 2.3% Amulet, p=0.01) 
  • 0 device embolizations occurred with WATCHMAN FLX vs. 15 with Amulet (0.1%; 95% CI: 0-0.3) 
  • WATCHMAN FLX demonstrated lower DRT than Amulet (1% vs 1.6%) 
  • No difference was observed for death or stroke between groups 

Procedural performance

WATCHMAN FLX showed a trend towards higher procedural success (p=0.08). Procedural success was achieved in 99.9% of WATCHMAN FLX patients (99.4% for Amulet, P=0.08)


WATCHMAN FLX showed a trend towards more frequent appendage occlusion (leaks >5mm; p=0.06). WATCHMAN FLX demonstrated fewer peri-device leaks >5mm than Amulet (0.01% vs 0.34%, p=0.06)

Peri Device
WATCHMAN FLX device with decorative teal overlay

1. Della Rocca, D., Magnocavallo, M., Gianni, C., Horton, R., Biase, L., Natale, A., Procedural and short-term follow-up outcomes of Amplatzer Amulet Occluder versus Watchman FLX Device: A Meta-Analysis, Heart Rhythm, February 2022,