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

Model Number	M635WU50270
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Thrombosis/Thrombus (4440)
Date of Event	04/26/2024
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
D4: detailed product information was not provided to bsc.We completed a good faith effort to obtain the information.Because the product is unknown at this time, we are unable to provide the complete udi and other product specific information.If additional details become available, a supplemental report will be submitted.
Event or Problem Description
It was reported that thrombosis occurred.A left atrial appendage (laa) closure procedure was performed, and a 27mm watchman flx closure device was implanted on (b)(6) 2024.The patient was discharged on warfarin for 6 weeks and then transitioned to dual antiplatelet therapy (dapt).On (b)(6) 2024, during a transesophageal echocardiography (tee), a small thrombus was noted.The patient was placed on xarelto for three (3) months.On (b)(6) 2024, tee imaging showed resolution of the thrombus.The patient was placed on 81mg of aspirin.During the routine one year follow up tee on (b)(6) 2025, imaging showed a thrombus on the insertion of the laao.The patient continued on 81mg aspirin.A computed tomography (ct) scan was performed on (b)(6) 2026, and imaging showed no thrombus.
Additional Manufacturer Narrative
D4: detailed product information was not provided to bsc.We completed a good faith effort to obtain the information.Because the product is unknown at this time, we are unable to provide the complete udi and other product specific information.If additional details become available, a supplemental report will be submitted.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
It was reported that thrombosis occurred.A left atrial appendage (laa) closure procedure was performed, and a 27mm watchman flx closure device was implanted on (b)(6) 2024.The patient was discharged on warfarin for 6 weeks and then transitioned to dual antiplatelet therapy (dapt).On (b)(6) 2024, during a transesophageal echocardiography (tee), a small thrombus was noted.The patient was placed on xarelto for three (3) months.On (b)(6) 2024, tee imaging showed resolution of the thrombus.The patient was placed on 81mg of aspirin.During the routine one year follow up tee on (b)(6) 2025, imaging showed a thrombus on the insertion of the laao.The patient continued on 81mg aspirin.A computed tomography (ct) scan was performed on (b)(6) 2026, and imaging showed no 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: 24389220
• Report Number: 2124215-2026-09299
• Device Sequence Number: 10622666
• Product Code: NGV
• UDI-Device Identifier: 08714729860501
• UDI-Public: (01)08714729860501
• Combination Product (Y/N): N
• Initial Reporter State: OR
• Initial Reporter Country: US
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2024
• 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): 03/24/2026

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: M635WU50270
• Device Catalogue Number: M635WU50270
• 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: 01/30/2026
• Supplement Date Received by Manufacturer: 03/20/2026
• Initial Report FDA Received Date: 02/19/2026
• Supplement Report FDA Received Date: 03/24/2026
• 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: 76 YR
• Patient Sex: Female