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 merge the findings of previous studies to calculate an overall or ‘absolute’ effect)
  • 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 WATCHMAN FLX vs. Amplatzer Amulet reveals superior procedural safety, higher procedural success, and better LAA closure with WATCHMAN FLX.

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 
  • WATCHMAN FLX demonstrated lower DRT than Amulet (1% vs 1.6%) 
  • No difference was observed for death or stroke between groups 


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,