MAUDE Adverse Event Report: BOSTON SCIENTIFIC CORPORATION WATCHMAN FLX? Pro; system, appendage closure, left atrial

Model Number	M635WU60350
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Thrombosis/Thrombus (4440)
Date of Event	07/30/2026
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
With all the available information, boston scientific (bsc) concludes: device technical analysis the watchman flx? pro remains implanted; therefore, returned device analysis could not be completed.Device history record review a review was completed of the device history records (dhr) for the watchman flx? pro, part # m635wu60350 batch # 0036043535.The dhr review confirmed that the device met all material, assembly, and performance specifications prior to distribution.Labeling review there was no evidence to suggest that the device was used in a manner inconsistent with the labeling.Watchman flx? pro instructions for use (ifu) lists potential complications, risks and adverse events that may be associated with the use of this device which include thrombosis.Risk review a risk review was completed and confirmed that the event of thrombosis was defined in the risk documentation.This event type has been accounted for during product risk analysis to support acceptable risk benefit for the product.Investigation conclusion based on a thorough review of the reported complaint, boston scientific has assigned an investigation conclusion code of no problem detected.
Event or Problem Description
It was reported that thrombosis occurred.A left atrial appendage (laa) closure procedure was performed, and a 35mm watchman flx pro closure device was implanted on (b)(6) 2026.The patient was discharged on eliquis and switched to dual antiplatelet therapy (dapt) at the routine 45 day follow up.The patient had a routine five (5) months follow up computed tomography (ct) and imaging showed a non-mobile 7x10mm lobulated device related thrombus (drt) located on the posterior margin of the closure device.The patient was then placed back on eliquis on (b)(6) 2026 and planned for a follow up transesophageal echocardiography (tee) in three (3) months.
Event or Problem Description
It was reported that thrombosis occurred.A left atrial appendage (laa) closure procedure was performed, and a 35mm watchman flx pro closure device was implanted on (b)(6) 2026.The patient was discharged on eliquis and switched to dual antiplatelet therapy (dapt) at the routine 45 day follow up.The patient had a routine five (5) months follow up computed tomography (ct) and imaging showed a non-mobile 7x10mm lobulated device related thrombus (drt) located on the posterior margin of the closure device.The patient was then placed back on eliquis on (b)(6) 2026 and planned for a follow up transesophageal echocardiography (tee) in three (3) months.

• Brand Name: WATCHMAN FLX? Pro
• Common Device Name: system, appendage closure, left atrial
• Manufacturer (Section D): BOSTON SCIENTIFIC CORPORATION; 300 boston scientific way; marlborough MA 01752
• Manufacturer (Section G): Boston Scientific Corporation; ballybrit business park; galway H91 Y 868; EI H91 Y868
• Manufacturer Contact: mary crawford ; 4100 hamline ave n; arden hills, MN 55112 ; +1(651)440-0979
• MDR Report Key: 50600088
• Report Number: 2124215-2026-45686
• Device Sequence Number: 16108504
• Product Code: NGV
• UDI-Device Identifier: 00191506004620
• UDI-Public: (01)00191506004620(17)280310(10)36043535
• Combination Product (Y/N): N
• Initial Reporter State: WI
• Initial Reporter Country: US
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2026
• Reporter Type: Manufacturer
• Report Source: Health Professional,Company Representative
• Initial Reporter Occupation: Physician
• Type of Report: Initial,Followup
• Report Date (Section B): 09/24/2026

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Operator of Device: Health Professional
• Device Model Number: M635WU60350
• Device Catalogue Number: M635WU60350
• Device Lot Number: 0036043535
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: Not provided
• Supplement Date Received by Manufacturer: 09/23/2026
• Initial Report FDA Received Date: 09/03/2026
• Supplement Report FDA Received Date: 09/24/2026
• Date Device Manufactured: 03/11/2025
• Is the Device Labeled for Single Use? (Y/N): Yes
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Initial
• Patient Sequence Number: 1
• Outcome Attributed to Adverse Event: Other
• Patient Age: 80 YR
• Patient Sex: Male