MAUDE Adverse Event Report: BOSTON SCIENTIFIC CORPORATION WATCHMAN FLX? Pro; system, appendage closure, left atrial

Model Number	M635WU60240
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Pericardial Effusion (3271)
Date of Event	09/15/2026
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported that pericardial effusion occurred.A left atrial appendage closure (laac) procedure was performed, and a 24mm watchman flx pro closure device was implanted.Approximately 8 months post implant the patient was scheduled to undergo atrial fibrillation ablation with a non-boston scientific ablation system.Baseline intracardiac echocardiogram was performed which noted a pericardial effusion that had not previously been seen in any of the post-laac transthoracic or transesophageal echocardiograms from post-procedure or 45-day follow-up.The ablation procedure was performed.No intervention was performed for the pericardial effusion.The treating physician commented that it was not large enough to perform pericardiocentesis.Computed tomography was ordered which the radiologist read as a trace effusion and noted the closure device looked fine.The treating physician was unsure why every other modality did not see the pericardial effusion and commented that the pericardial effusion was "definitely there".The treating physician is concerned the effusion was caused by erosion from the implanted closure device.The patient was asymptomatic and stable.

• 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 H91 Y 868; EI H91 Y868
• Manufacturer Contact: mary crawford ; 4100 hamline ave n; arden hills, MN 55112 ; +1(651)440-0979
• MDR Report Key: 50882216
• Report Number: 2124215-2026-50862
• Device Sequence Number: 9762381
• Product Code: NGV
• UDI-Device Identifier: 00191506004590
• Combination Product (Y/N): N
• Initial Reporter State: PA
• Initial Reporter Country: US
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2026
• Reporter Type: Manufacturer
• Report Source: Health Professional,Company Representative
• Initial Reporter Occupation: Physician
• Type of Report: Initial
• Report Date (Section B): 09/24/2026

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: M635WU60240
• Device Catalogue Number: M635WU60240
• Device Lot Number: 0037460697
• 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: 09/15/2026
• Initial Report FDA Received Date: 09/24/2026
• Date Device Manufactured: 09/16/2025
• 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: Other
• Patient Age: 69 YR
• Patient Sex: Male