Left Atrial Appendage Closure Device

Built off the most studied, most implanted LAAC device in the world, WATCHMAN FLX is a proven alternative to long-term OAC therapy1 for stroke risk reduction in patients with non-valvular atrial fibrillation.

WATCHMAN FLX was studied in the PINNACLE FLX US IDE Clinical Trial. The study was designed to establish the procedural safety and closure efficacy of new generation LAAC device, WATCHMAN FLX.





Surpass Registry

The SURPASS analysis of the NCDR-LAAO Registry™ includes the largest number of commercial WATCHMAN FLX patients to date. This data reinforces the outstanding safety of WATCHMAN FLX with 0.37% major procedural adverse event rate within 7 days or hospital discharge and 98% procedural success rate in > 16,000 real-world NVAF patients.1

Study Design

  • SURPASS assesses the safety and efficacy outcomes in patients in the NCDR-LAAO Registry that received a commercial WATCHMAN FLX device
  • This SURPASS analysis includes 16,048 patients receiving a WATCHMAN FLX device between August 5, 2020 and March 31, 2021
  • SURPASS will continue to assess WATCHMAN FLX patients included in the NCDR-LAAO Registry from August 2020 through August 2022 and will follow these patients through 2 years post-implant.

Mean baseline patient characteristics (N=16,048)

  • Average age/years: 76.1 ± 7.9
  • CHA2DS2-VASc: 4.8 ± 1.5
  • HAS-BLED: 2.4 ± 1.0
  • 40% women
  • 62% with prior clinically relevant bleeding event
Safety Endpoint

SURPASS demonstrated 0.37% major procedural adverse event rate within 7 days or hospital discharge in 16,048 commercial patients and confirmed the trusted safety profile of WATCHMAN FLX in real-world clinical practice setting.
SURPASS data reinforces WATCHMAN FLX procedural success with 98% of patients implanted (N=16,048/16,446)1 across nearly all anatomies in a real-world setting, confirming that WATCHMAN FLX real world experience replicates clinical trial outcomes.

98% people icons


The SURPASS Data reinforces the excellent safety profile WATCHMAN FLX demonstrated in the PINNACLE FLX Trial, with the largest (n=16,048) real-world WATCHMAN FLX patients studied to date.


Comparison with PINNACLE FLX2
45-Day Outcomes

Comparison with PINNACLE FLX


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

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)



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

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

Primary Outcome Complete Seal* Based on CT Imaging

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

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



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



PINNACLE FLX Clinical Study


Primary Outcome Evaluation of a Next Generation LAAC Device: The PINNACLE FLX Trial

presented by Dr. Shephal K. Doshi

May 8, 2020

The PINNACLE FLX US IDE Trial was designed to establish the Procedural Safety and LAA Closure Efficacy with the WATCHMAN FLX LAAC Device.

Study Design

  • 400 patient, 29 US site, single arm, non-randomized trial evaluating WATCHMAN FLX for non-inferiority to safety and efficacy performance goals based on the WATCHMAN™ device.
  • Follow-up: 45 days (+TEE), 6 months, 12 months (+TEE), 18 months, and 24 months
  • Patient Characteristics: Average CHA2DS2-VASc of 4.2±1.5, Average HAS-BLED of 2.0±1.0
  • Post Implant Drug Regimen: NOAC/ASA for 45 days, Clopidogrel/ASA to 6 months, ASA post 6 months
  • Primary Safety Endpoint: All-cause death, ischemic stroke, systemic embolism, or device- or procedure-related adverse events requiring surgery or major endovascular intervention within 7 days following the procedure or by hospital discharge, whichever is later.
  • Primary Efficacy Endpoint: The rate of effective LAA closure defined as any peri-device flow ≤5mm demonstrated by TEE at 12 months
  • Secondary Efficacy Endpoint: The occurrence of ischemic stroke or systemic embolism at 24 months from the time of enrollment
  • Inclusion/exclusion criteria is consistent with WATCHMAN clinical study inclusion/exclusion criteria. Patients must be eligible for short-term NOAC vs warfarin in previous clinical studies.

Primary Safety Endpoints

All-cause death, ischemic stroke, systemic embolism, or device- or procedure-related adverse events requiring surgery or major endovascular intervention within 7 days following the procedure or by hospital discharge, whichever is later.
primary safety statistics
primary safety endpoint graph
* Based on the combined rate observed in PREVAIL(1) and CAP2(2), plus a clinically acceptable delta.
primary safety endpoint graph
1 Holmes, DR., et al, (2014). J AM Coll Cardiol 64(1): 1-12.
2 Holmes, DR., et al, JACC 2019.

Primary Efficacy Endpoints

The rate of effective LAA closure defined as any peri-device flow ≤5mm demonstrated by TEE at 12 months.


primary efficacy endpoint graph
*LAA closure at 12 months is defined as any peri-device flow with jet size ≤5mm per core laboratory-assessed TEE
** Performance goal pased on the rates observed in PREVAIL(1) and CAP2(2), minus a clinically relevant delta

Procedure Performance

98.8% Procedure/Implant Success
* Implant success defined as successful delivery and release of a WATCHMAN FLX device into the LAA


DRT at 12 months follow-up
*Device-Related Thrombus
**Doshi SK. Primary outcome evaluation of a next generation LAAC device: the PINNACLE FLX trial. Presented on: May 8, 2020. HRS 2020.

Designed to Treat Widest Range of Patient Anatomies

WATCHMAN FLX sizes range from (20mm - 35mm)





Discussion of the PINNACLE FLX Clinical Trial

Dr. Kenneth Stein, Senior Vice President, Chief Medical Officer, Rhythm Management at Boston Scientific
Dr. Ian Meredith, Executive Vice President, Global Chief Medical Officer, Boston Scientific