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	02/16/2026
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported that there was a device related thrombus.A left atrial appendage (laa) closure procedure was being performed.A watchman access system (was) and a 27mm watchman flx laa closure device & delivery system (wds) were selected to be used.The procedure was successfully completed with the closure device implanted in the laa of the patient.There were no patient complications that were reported to have occurred.Three (3) years post procedure the patient was having an open-heart surgery.A transesophageal echocardiogram (tee) imaging procedure was performed.The imaging showed a mass/thrombus on the face of the closure device.The closure device is well positioned with no leaks or gaps.The physician removed the mass without complications.There were no other complications that were reported to have occurred.The patient remains hospitalized due to normal recovery period post open-heart surgery.
Additional Manufacturer Narrative
The device was not returned for analysis as the device remains implanted; therefore, a technical analysis could not be performed.It was confirmed this device met manufacturing specification prior to distribution and there were no manufacturing deviations which could have contributed to the reported event.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 there was a device related thrombus.A left atrial appendage (laa) closure procedure was being performed.A watchman access system (was) and a 27mm watchman flx laa closure device & delivery system (wds) were selected to be used.The procedure was successfully completed with the closure device implanted in the laa of the patient.There were no patient complications that were reported to have occurred.Three (3) years post procedure the patient was having an open-heart surgery.A transesophageal echocardiogram (tee) imaging procedure was performed.The imaging showed a mass/thrombus on the face of the closure device.The closure device is well positioned with no leaks or gaps.The physician removed the mass without complications.There were no other complications that were reported to have occurred.The patient remains hospitalized due to normal recovery period post open-heart surgery.

• 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: 24405090
• Report Number: 2124215-2026-09654
• Device Sequence Number: 15521266
• Product Code: NGV
• UDI-Device Identifier: 08714729860501
• UDI-Public: (01)08714729860501(17)260713(10)32016951
• Combination Product (Y/N): N
• Initial Reporter State: FL
• 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,Followup
• Report Date (Section B): 04/28/2026

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 Expiration Date: 07/13/2026
• Device Model Number: M635WU50270
• Device Catalogue Number: M635WU50270
• Device Lot Number: 0032016951
• 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: 02/16/2026
• Supplement Date Received by Manufacturer: 04/22/2026
• Initial Report FDA Received Date: 02/20/2026
• Supplement Report FDA Received Date: 04/28/2026
• Date Device Manufactured: 07/14/2023
• 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: Required Intervention
• Patient Age: 71 YR
• Patient Sex: Male