The Focus of the Study is to Reduce the Risk of Stroke and Life-threatening Bleeding Events in Patients With Non-valvular Atrial FibrillationNCT05324371

WATCHMAN FLX™ CT Study

A study testing Watchman FLX Device in people with The Focus of the Study is to Reduce the Risk of Stroke and Life-threatening Bleeding Events in Patients With Non-valvular Atrial Fibrillation, run by Boston Scientific Corporation at 1 site in Denmark.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

WATCHMAN FLX™ CT is a prospective, single-arm, single-center, post-market investigation to assess device tissue coverage in subjects with non-valvular atrial fibrillation (AF) who receive the WATCHMAN FLX device to reduce the risk of stroke. Serial advanced imaging modalities such as CT and TEE will be used. Read more about this study

Who is it for?: Ages 18 years and older
Conditions the study is for: The Focus of the Study is to Reduce the Risk of Stroke and Life-threatening Bleeding Events in Patients With Non-valvular Atrial Fibrillation
What is being tested?: Watchman FLX Device
Type of treatment: Medical device
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 25 participants
Where: 1 siteDenmark
Study dates: 9 Nov 2022to 23 Jan 2025
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 years and older
All sexes
No healthy volunteers
Adult, Older adult

Who may be able to join

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 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.

Who cannot join

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 transient ischemic attack (TIA) within the 30 days prior to enrollment.

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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.

Trial locations and contacts

1 site in 1 country.

Denmark1 site

Aarhus University Hospital
Aarhus

Other trials in Denmark

About this study

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

Conditions: The Focus of the Study is to Reduce the Risk of Stroke and Life-threatening Bleeding Events in Patients With Non-valvular Atrial Fibrillation
Being tested: Watchman FLX Device

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Watchman FLX DeviceDevice
Left atrial appendage closure using the Watchman FLX device

Study groups in NCT05324371
Study group	Role	What they receive
Device Arm	Experimental	WATCHMAN FLX™ device implantation Receives: Device: Watchman FLX Device

What is being measured

The primary outcome is the main question the study is designed to answer.

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
Measured: 14 days to 3 months post implant

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

9 Nov 202223 Jan 2025

First posted12 Apr 2022
Study start9 Nov 2022
Primary completion30 May 2024
Study completion23 Jan 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for The Focus of the Study is to Reduce the Risk of Stroke and Life-threatening Bleeding Events in Patients With Non-valvular Atrial FibrillationStudies of the same condition, open and under way.
More trials run by Boston Scientific CorporationThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase N/A
Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Enrolment: 25 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05324371
Sponsor's protocol ID: S2423
Status last verified: May 2025
First submitted: 17 Mar 2022
Last updated: 1 Jul 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No: The data and study protocol for this clinical trial may be made available to other researchers in accordance with the Boston Scientific Data Sharing Policy (http://www.bostonscientific.com/en-US/data-sharing-requests.html).

Study at a glance

From the registry record, last updated by the sponsor on 1 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Pilot Study to Assess WATCHMAN FLX™ Implants by Cardiac Computed Tomography, Magnetic Resonance Imaging and Transesophageal Echocardiography: WATCHMAN FLX™ CT
ClinicalTrials.gov ID: NCT05324371
Acronym / sponsor ID: S2423
Conditions: The Focus of the Study is to Reduce the Risk of Stroke and Life-threatening Bleeding Events in Patients With Non-valvular Atrial Fibrillation
Study type: Interventional
Recruitment status: Completed
Enrolment: 25 participants (actual)
Lead sponsor: Boston Scientific CorporationIndustry (pharma, biotech, devices)
Study start: 9 Nov 2022 (actual)
Primary completion: 30 May 2024 (actual)
Study completion: 23 Jan 2025 (actual)
First posted: 12 Apr 2022 (actual)
Results: Posted 1 Jul 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Number of arms: 1

Arm	Type	Receives
Device Arm	Experimental	Device: Watchman FLX DeviceWATCHMAN FLX™ device implantation

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (6 listed)

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 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.

Key exclusion criteria (20 listed)

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.).

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Watchman FLX DeviceLeft atrial appendage closure using the Watchman FLX device	Device	Device Arm

Primary outcome

Number of Participants With Any Hypoattenuated Thickening (HAT) on the Surface of the Device
Time frame: 14 days to 3 months post implant
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

Results and safety

Results posted to the registry on 1 Jul 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Device Arm	25	23

Primary outcome: Number of Participants With Any Hypoattenuated Thickening (HAT) on the Surface of the Device

Time frame: 14 days to 3 months post implant. Count of participants. Unit: Participants

Measure	14 Days n = 24	45 Days n = 23	3 Months n = 23
Value	5	3	2

Adverse events

Time frame: 1 Year. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Device Arm	10 of 25 (40%)	4 of 25 (16%)	1 of 25

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 1 Jul 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: No. The data and study protocol for this clinical trial may be made available to other researchers in accordance with the Boston Scientific Data Sharing Policy (http://www.bostonscientific.com/en-US/data-sharing-requests.html).

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Jens Erik Nielsen-Kudsk, MD principal investigator

Aarhus University Hospital Skejby

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 6 inclusion and 20 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 1 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Denmark. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 1 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of Participants With Any Hypoattenuated Thickening (HAT) on the Surface of the Device (time frame: 14 days to 3 months post implant). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05324371.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Jul 2025.