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

Model Number	M635WU60200
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Thrombosis/Thrombus (4440)
Date of Event	08/01/2025
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
D4 lot number: reported as 3632768 however batch/lot number provided has discrepancy in system.Good faith efforts have been made to attempt to get information.If additional information is received, a supplemental will be submitted with the updates.
Event or Problem Description
Reported via patient call center.It was reported thrombosis occurred.A left atrial appendage (laa) closure procedure was performed, and a 20mm watchman flx pro closure device was implanted on (b)(6) 2025.The patient was discharged.The patient reported into the watchman patient call center that they were placed on plavix/aspirin combination post watchman implant.Patient noted that the routine 45-day follow up visit, imaging showed device well seated and no evidence of thrombosis.The patient was taken off plavix at that time.The patient said that the surgeon told her that he did not request/require any additional follow ups at the 90 day or six (6) month time points.At the end of year 2025, the patient reported she went in for a computed tomography (ct) scan requested by her cardiologist unrelated to the watchman implant procedure and was told that there is evidence of thrombosis in the left atrial appendage.Patient noted she did not and has not contacted her watchman surgeon to notify the surgeon of what was happening.Patient was directed to reach out to the watchman surgeon to let him know what is going on.Patient taking aspirin at this time.
Additional Manufacturer Narrative
The device was not returned for analysis as the device remains implanted; therefore, a technical analysis could not be performed.Based on a thorough review of the reported complaint, boston scientific has assigned an investigation conclusion code of known inherent risk of device.
Event or Problem Description
Reported via patient call center.It was reported thrombosis occurred.A left atrial appendage (laa) closure procedure was performed, and a 20mm watchman flx pro closure device was implanted on (b)(6) 2025.The patient was discharged.The patient reported into the watchman patient call center that they were placed on plavix/aspirin combination post watchman implant.Patient noted that the routine 45-day follow up visit, imaging showed device well seated and no evidence of thrombosis.The patient was taken off plavix at that time.The patient said that the surgeon told her that he did not request/require any additional follow ups at the 90 day or six (6) month time points.At the end of year 2025, the patient reported she went in for a computed tomography (ct) scan requested by her cardiologist unrelated to the watchman implant procedure and was told that there is evidence of thrombosis in the left atrial appendage.Patient noted she did not and has not contacted her watchman surgeon to notify the surgeon of what was happening.Patient was directed to reach out to the watchman surgeon to let him know what is going on.Patient taking aspirin at this time.

• 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 ; EI
• Manufacturer Contact: rachel shields ; 4100 hamline ave n; arden hills, MN 55112 ; 6512422111
• MDR Report Key: 24403391
• Report Number: 2124215-2026-09633
• Device Sequence Number: 8168330
• Product Code: NGV
• UDI-Device Identifier: 00191506004583
• UDI-Public: (01)00191506004583
• Combination Product (Y/N): N
• Initial Reporter State: NY
• Initial Reporter Country: US
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2025
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Consumer
• Initial Reporter Occupation: Other
• Type of Report: Initial,Followup
• Report Date (Section B): 03/23/2026

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: M635WU60200
• Device Catalogue Number: M635WU60200
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: No
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 02/02/2026
• Supplement Date Received by Manufacturer: 03/18/2026
• Initial Report FDA Received Date: 02/20/2026
• Supplement Report FDA Received Date: 03/23/2026
• 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: 68 YR
• Patient Sex: Female