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

Model Number	M635WU50240
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Thrombosis/Thrombus (4440)
Date of Event	12/19/2025
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
D6a: implant date estimated as exact date is unknown; event reported to have occurred in 2023.
Event or Problem Description
It was reported that thrombosis occurred.A left atrial appendage closure procedure was performed and a 24mm watchman flx closure device was implanted.Approximately 2 years later the patient presented for atrial fibrillation ablation and underwent transesophageal echocardiogram (tee).The tee identified a thrombus attached to the face of the closure device.The patient was restarted on anticoagulation, and the thrombus is expected to be reassessed in 45 days.The patient was discharged.

• 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: 23948648
• Report Number: 2124215-2026-00154
• Device Sequence Number: 21503602
• Product Code: NGV
• UDI-Device Identifier: 08714729860495
• UDI-Public: (01)08714729860495
• Combination Product (Y/N): N
• Initial Reporter State: IA
• Initial Reporter Country: US
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2023
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Health Professional,Company Representative
• Initial Reporter Occupation: Physician
• Type of Report: Initial
• Report Date (Section B): 01/02/2026

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: M635WU50240
• Device Catalogue Number: M635WU50240
• 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: 12/19/2025
• Initial Report FDA Received Date: 01/02/2026
• 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
• Patient Race: White