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

Model Number	M635WU50350
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Codes	Stroke/CVA (1770); Thrombosis/Thrombus (4440)
Date of Event	04/08/2024
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
B3: estimated as 08-apr-2024 as the accepted date for the article is noted as such.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.Literature citation: chatani, r., kubo, s., tasaka, h., maruo, t., kadota, k.(2024).Ischemic stroke associated with high-grade pedunculated device-related thrombosis following left atrial appendage closure.J arrhythmia.2024; 40: 620-623.Doi.Org/10.1002/joa3.13042.
Event or Problem Description
Reported via literature article.It was reported that thrombosis and cerebral vascular accident occurred.An 80-year-old male patient underwent percutaneous left atrial appendage closure (laac) using a 35mm watchman flx closure device due to prior embolic events despite oral anticoagulation (oac) and elevated bleeding risk, resulting in the effective sealing of the left atrial appendage.The patient was discharged without complications on postoperative day two (2).A follow-up transesophageal echocardiography (tee) was performed on day 44 and confirmed closure device stability without leak or thrombus.According to local protocol, apixaban was discontinued, and dual antiplatelet therapy (aspirin and prasugrel) was initiated.On postoperative day 236, follow-up coronary angiography revealed no restenosis, leading to the decision to continue only prasugrel 3.75 mg daily, with the discontinuation of aspirin.On postoperative day 314, the patient was hospitalized with left homonymous hemianopia.Brain magnetic resonance imaging (mri) confirmed an ischemic stroke, and tee revealed a high-grade pedunculated grade 3 device-related thrombus (drt) measuring 17 x 20 mm attached to the surface of the closure device.The patient was restarted on apixaban 5 mg twice a day.At two months follow-up, tee showed complete thrombus resolution.Long-term anticoagulation with apixaban was continued due to high risk of recurrent thromboembolism.There were no further thromboembolic or bleeding events during follow-up.

• 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: 23379575
• Report Number: 2124215-2025-76116
• Device Sequence Number: 15753692
• Product Code: NGV
• UDI-Device Identifier: 08714729860525
• UDI-Public: (01)08714729860525
• Combination Product (Y/N): N
• Initial Reporter Country: JA
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Other,Foreign,Literature,Health Professional
• Initial Reporter Occupation: Physician
• Type of Report: Initial
• Report Date (Section B): 10/24/2025

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: M635WU50350
• Device Catalogue Number: M635WU50350
• 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: 10/17/2025
• Initial Report FDA Received Date: 10/24/2025
• 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: Hospitalization; Required Intervention
• Patient Age: 80 YR
• Patient Sex: Male