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

Model Number	M635WU60200
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Pericardial Effusion (3271)
Date of Event	03/13/2026
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported a pericardial effusion occurred.A concomitant ablation was performed prior to the left atrial appendage closure (laac) procedure.A watchman fxd double curve access system (was) and a 20 mm watchman flx pro laa closure device & delivery system (wds) were selected for the laac.At the start of the ablation procedure, the physician attempted to use 4d nuvision intracardiac echocardiography (ice) alone.After completing the ablation, the laac procedure began under ice guidance; however, image quality was suboptimal, prompting insertion of a transesophageal echocardiography (tee) probe.A baseline effusion assessment was not initially performed.Following several deployment attempts with the wds, the physician observed a pericardial effusion near the right ventricular apex, although the patient remained hemodynamically stable.It was unclear whether the effusion was pre-existing.There was no intervention required to treat the effusion.The 20mm closure device was successfully implanted, and the patient was kept overnight for observation.No patient complications were reported.
Event or Problem Description
It was reported a pericardial effusion occurred.A concomitant ablation was performed prior to the left atrial appendage closure (laac) procedure.A watchman fxd double curve access system (was) and a 20 mm watchman flx pro laa closure device & delivery system (wds) were selected for the laac.At the start of the ablation procedure, the physician attempted to use 4d nuvision intracardiac echocardiography (ice) alone.After completing the ablation, the laac procedure began under ice guidance; however, image quality was suboptimal, prompting insertion of a transesophageal echocardiography (tee) probe.A baseline effusion assessment was not initially performed.Following several deployment attempts with the wds, the physician observed a pericardial effusion near the right ventricular apex, although the patient remained hemodynamically stable.It was unclear whether the effusion was pre-existing.There was no intervention required to treat the effusion.The 20mm closure device was successfully implanted, and the patient was kept overnight for observation.No patient complications were reported.
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.

• 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 ; EI
• Manufacturer Contact: rachel shields ; 4100 hamline ave n; arden hills, MN 55112 ; 6512422111
• MDR Report Key: 24634188
• Report Number: 2124215-2026-15015
• Device Sequence Number: 8596569
• Product Code: NGV
• UDI-Device Identifier: 00191506004583
• UDI-Public: (01)00191506004583(17)280626(10)36855886
• Combination Product (Y/N): N
• Initial Reporter State: RI
• Initial Reporter Country: US
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2026
• 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): 05/04/2026

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: M635WU60200
• Device Catalogue Number: M635WU60200
• Device Lot Number: 0036855886
• 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: 03/13/2026
• Supplement Date Received by Manufacturer: 05/01/2026
• Initial Report FDA Received Date: 03/18/2026
• Supplement Report FDA Received Date: 05/04/2026
• Date Device Manufactured: 06/27/2025
• 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; Other
• Patient Age: 75 YR
• Patient Sex: Male
• Patient Race: White