MAUDE Adverse Event Report: BOSTON SCIENTIFIC CORPORATION WATCHMAN FLX?; SYSTEM, APPENDAGE CLOSURE, LEFT ATRIAL

Model Number	M635WU50350
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Thrombosis/Thrombus (4440)
Date of Event	09/08/2025
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported that thrombosis occurred.A left atrial appendage (laa) closure procedure was being performed and a 35mm watchman flx pro laa closure device was implanted on (b)(6) 2022, and the patient was discharged without incident.On (b)(6) 2025, the watchman coordinator informed of a non-mobile thrombus located in the left atrium on top of the closure device.The thrombus was discovered via computed tomography (ct) scan for an unrelated procedure.The patient was placed back on anticoagulation medication.
Additional Manufacturer Narrative
B5 describe event or problem: updated with additional information received.
Event or Problem Description
It was reported that thrombosis occurred.A left atrial appendage (laa) closure procedure was being performed and a 35 mm watchman flx pro laa closure device was implanted on (b)(6) 2022, and the patient was discharged without incident.On (b)(6) 2025, the watchman coordinator informed of a non-mobile thrombus located in the left atrium on top of the closure device.The thrombus was discovered via computed tomography (ct) scan for an unrelated procedure.The patient was placed back on anticoagulation medication.It was further reported that transesophageal echocardiography (tee) was performed to confirm the thrombus.

• Brand Name: WATCHMAN FLX?
• 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 ; EI
• Manufacturer Contact: rachel shields ; 4100 hamline ave n; arden hills, MN 55112 ; 6512422111
• MDR Report Key: 23168111
• Report Number: 2124215-2025-68137
• Device Sequence Number: 9639531
• Product Code: NGV
• UDI-Device Identifier: 08714729860525
• UDI-Public: (01)08714729860525(17)250830(10)30062691
• Combination Product (Y/N): N
• Initial Reporter State: IL
• Initial Reporter Country: US
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2022
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Health Professional,Company Representative
• Initial Reporter Occupation: Other Health Care Professional
• Type of Report: Initial,Followup
• Report Date (Section B): 10/18/2025

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 Expiration Date: 08/30/2025
• Device Model Number: M635WU50350
• Device Catalogue Number: M635WU50350
• Device Lot Number: 0030062691
• 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: 09/08/2025
• Supplement Date Received by Manufacturer: 10/16/2025
• Initial Report FDA Received Date: 09/29/2025
• Supplement Report FDA Received Date: 10/18/2025
• Date Device Manufactured: 08/31/2022
• 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: 88 YR
• Patient Sex: Male