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

Model Number	M635WU50310
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Thrombosis/Thrombus (4440)
Date of Event	09/06/2024
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 31mm 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.The patient was discharged on a plavix and aspirin medication regiment.The patient came in for their 45 day follow up imaging procedure.The imaging showed that the closure device was well placed and there were no issues.Three (3) months later the patient had a computed tomography scan on their kidneys and the physician noted that there was a thrombus present on the closure device at this time.The patient had their six (6) month follow up transesophageal echocardiogram (tee) procedure.The tee imaging showed that the thrombus was still present on the closure device.The patient was then placed on warfarin in response to this event.Eight (8) months post procedure another tee was performed, and a large thrombus was still present on the closure device.The patient has remained on warfarin.There were no other complications that have been reported to have occurred with these events.
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 31mm 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.The patient was discharged on a plavix and aspirin medication regiment.The patient came in for their 45 day follow up imaging procedure.The imaging showed that the closure device was well placed and there were no issues.Three (3) months later the patient had a computed tomography scan on their kidneys and the physician noted that there was a thrombus present on the closure device at this time.The patient had their six (6) month follow up transesophageal echocardiogram (tee) procedure.The tee imaging showed that the thrombus was still present on the closure device.The patient was then placed on warfarin in response to this event.Eight (8) months post procedure another tee was performed, and a large thrombus was still present on the closure device.The patient has remained on warfarin.There were no other complications that have been reported to have occurred with these events.

• 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: 24292563
• Report Number: 2124215-2026-07136
• Device Sequence Number: 9332555
• Product Code: NGV
• UDI-Device Identifier: 08714729860518
• UDI-Public: (01)08714729860518(17)261009(10)32601585
• Combination Product (Y/N): N
• Initial Reporter State: MT
• 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: Consumer
• Initial Reporter Occupation: Other
• Type of Report: Initial,Followup
• Report Date (Section B): 04/09/2026

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: M635WU50310
• Device Catalogue Number: M635WU50310
• Device Lot Number: 0032601585
• 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: 01/28/2026
• Supplement Date Received by Manufacturer: 04/08/2026
• Initial Report FDA Received Date: 02/09/2026
• Supplement Report FDA Received Date: 04/09/2026
• Date Device Manufactured: 10/10/2023
• 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: Other
• Patient Age: 72 YR
• Patient Sex: Male