Watchman FLX Pro CT Pilot Study

A Pilot Study to Assess WATCHMAN FLX™ Pro Implants by Cardiac Computed Tomography, Magnetic Resonance Imaging and Transesophageal Echocardiography: WATCHMAN FLX Pro CT

The primary objective of this study is to measure device tissue coverage post-implantation of the WATCHMAN FLX™ Pro Left Atrial Appendage Closure (LAAC) Device (WATCHMAN FLX Pro) using the serial advanced imaging modalities of cardiac computed tomography (CT) and transesophageal echocardiography (TEE) and assess its relationship, if any, to clinical events.

Study Overview

• Status: Completed
• Conditions: Non-valvular Atrial Fibrillation (AF)
• Intervention / Treatment: Device: Left atrial appendage closure device WM FLX Pro

Detailed Description

WATCHMAN FLX™ Pro CT is a prospective, single-arm, single-center, premarket investigation to assess device tissue coverage in subjects with non-valvular atrial fibrillation (AF) who receive the WATCHMAN FLX Pro device to reduce the risk of stroke. Serial advanced imaging modalities such as CT and TEE will be used. A core laboratory will independently assess select results.

A subject is considered enrolled in the study when the subject or the subject's legally authorized representative signs an Informed Consent Form (ICF) approved by the Independent Ethics Committee (IEC). Up to 50 subjects in whom placement of a WATCHMAN FLX Pro device is attempted will be enrolled.

A baseline assessment including TEE and/or CT imaging with optional cardiac magnetic resonance imaging (MRI) will be done within 7 days prior to the index procedure following core laboratory guidelines. Follow-up clinical assessment and imaging will occur at 14 days, 45 days, and 3 months post index procedure; only clinical assessment will be required at 12 months (unless an in-person assessment is required based on other data). Subjects who are enrolled but not implanted with a WATCHMAN FLX Pro LAAC device will be followed for safety through 12 months after the initial attempted index procedure but will not undergo imaging assessments or evaluation of biochemical markers including measures of coagulation, platelet and endothelial activation and inflammation.

• Study Type: Interventional
• Enrollment (Actual): 43
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Aarhus, Denmark
    • Aarhus University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Subject is of legal age to participate in the study per the laws of their respective geography.
• Subject has documented non-valvular atrial fibrillation (i.e., atrial fibrillation in the absence of moderate or greater mitral stenosis or a mechanical heart valve).
• Subject is clinically indicated for a WATCHMAN FLX Pro device.
• Subject is deemed suitable for the protocol-defined pharmacologic regimen.
• Subject or legal representative is able to understand and willing to provide written informed consent to participate in the study.
• Subject is able and willing to return for required follow-up visits and examinations.

Exclusion Criteria:

• Exclusion criteria are listed below.
• Subject is currently enrolled in another investigational study, except if the subject is participating in a mandatory governmental registry, or a purely observational registry with no associated treatment.
• Subject has eGFR <30 mL/min (chronic kidney disease stage IV or stage V).
• Subject is contraindicated for TEE.
• Subject requires long-term anticoagulation therapy for reasons other than AF-related stroke risk reduction (e.g., due to an underlying hypercoagulable state).
• Subject had or is planning to have any cardiac or non-cardiac intervention or surgical procedure within 30 days prior to or 60 days after implant (including, but not limited to, cardioversion, percutaneous coronary intervention, cardiac ablation, cataract surgery, etc.).
• Subject had a prior stroke (of any cause, whether ischemic or hemorrhagic) or TIA within the 30 days prior to enrollment.
• Subject had a prior major bleeding event per ISTH definitions within the 30 days prior to enrollment. Lack of resolution of related clinical sequelae or planned and pending interventions to resolve bleeding/bleeding source are a further exclusion regardless of timing of the bleeding event.
• Subject has an active bleed.
• Subject has a reversible cause for AF or has transient AF.
• Subject has no LAA or the LAA is surgically ligated.
• Subject has had a myocardial infarction (MI) documented in the clinical record as either a non-ST elevation MI (NSTEMI) or as an ST-elevation MI (STEMI), with or without intervention, within 30 days prior to enrollment.
• Subject has a history of atrial septal repair or has an atrial septal defect/patent foramen ovale (ASD/PFO) device.
• Subject has a known contraindication to percutaneous catheterization procedure.
• Subject has a cardiac tumor.
• Subject has signs/symptoms of acute or chronic pericarditis.
• Subject has an active infection.
• There is evidence of tamponade physiology.
• Subject has New York Heart Association Class IV congestive heart failure at the time of enrollment.
• Subject is of childbearing potential and is, or plans to become, pregnant during the time of the study (method of assessment per study physician's discretion).
• Subject has a documented life expectancy of less than 6 months.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Watchman FLX Pro	Device: Left atrial appendage closure device WM FLX Pro; Left atrial appendage closure

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Any Hypoattenuated Thickening (HAT) on the Surface of the Device	Serial measurement of any HAT on the surface of the device at 14 days, 45 days and 3 months post implant as assessed by core lab using CT imaging	14 days to 3 months post implant

Collaborators and Investigators

• Sponsor: Boston Scientific Corporation

Study record dates

Study Major Dates

• Study Start (Actual): March 24, 2023
• Primary Completion (Actual): October 14, 2024
• Study Completion (Actual): June 18, 2025

Study Registration Dates

• First Submitted: September 29, 2022
• First Submitted That Met QC Criteria: October 3, 2022
• First Posted (Actual): October 5, 2022

Study Record Updates

• Last Update Posted (Estimated): December 9, 2025
• Last Update Submitted That Met QC Criteria: December 7, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Atrial Fibrillation
• Other Study ID Numbers: S2517

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No