implanter wearing mask in hospital

Clinical evidence


Lives changed and counting


Recent studies

Pre-clinical data

The fluoropolymer-coated WATCHMAN FLX™ Pro device showed significantly less thrombus and reduced inflammation in a challenging canine model. Mechanistic studies demonstrated that the WATCHMAN FLX Pro device binds more albumin, leading to reduced platelet activation, less inflammation, and greater endothelial coverage (EC).1  


The SURPASS 1 Year Outcomes analysis of the NCDR-LAAO Registry™ now includes the largest number of commercial WATCHMAN FLX™ Device patients to date. These data continue to support the best-in-class safety and long-term efficacy of the WATCHMAN FLX Device.2


The Meta-Analysis is 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.3


SEAL FLX is the first study to compare Amulet exclusively to WATCHMAN FLX and the results demonstrated that statistically superior complete occlusion* was achieved when using WATCHMAN FLX.4


The U.S. IDE Trial was designed to establish the procedural safety and left atrial appendage closure efficacy of WATCHMAN FLX™ LAAC device.5

Clinical trials

Active trials


With over 400,000 patients implanted with the WATCHMAN platform, CHAMPION-AF extends Boston Scientific’s LAAC leadership by evaluating WATCHMAN FLX™ as a safe and effective first-line option versus NOAC to reduce stroke risk.

OPTION clinical trial

The OPTION clinical trial is a randomized controlled trial comparing the safety and effectiveness of left atrial appendage closure (LAAC) to oral anticoagulation (OAC) therapy for stroke protection in post-ablation patients with atrial fibrillation.

Clinical trial results

PINNACLE FLX clinical study

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

* 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)
1. Saliba et al. Enhanced Thromboresistance and Endothelialization of a Novel Fluoropolymer-Coated Left Atrial Appendage Closure Device, JACC: Clinical Electrophysiology, 2023.
2. Kapadia, S et al. Late Breaking Clinical Trial, CRT 2022.

3. Della Rocca et al, Procedural and Short-Term Follow-Up Outcomes of Amplatzer Amulet Occluder versus WATCHMAN FLX Device: A Meta-Analysis, Heart Rhythm 2022.
4. Korsholm-K et al. Left atrial appendage sealing performance of the Amplatzer Amulet and Watchman FLX device. J Interv Card Electrophysiol. 2022 Aug 11. doi: 10.1007/s10840-022-01336-4.
5. Kar S, et al. Primary Outcome Evaluation of a Next-Generation Left Atrial Appendage Closure Device: Results From the PINNACLE FLX Trial. Circulation. 2021;143:1754-1762.