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	Chest Pain (1776); Dyspnea (1816); Cardiac Perforation (2513); Pericardial Effusion (3271); Thrombosis/Thrombus (4440); Pericarditis (4448)
Date of Event	11/19/2025
Type of Reportable Event	Serious Injury
Event or Problem Description
Reported via journal article.It was reported a pericardial effusion occurred.A left atrial appendage (laa) closure procedure was performed, and a 35mm watchman flx closure device was implanted.The procedure was uneventful, and the patient was discharged home on apixaban and aspirin.A transesophageal echocardiogram (tee) performed during the procedure confirmed successful device placement without any pericardial effusion (pe).A repeat tee 45 days later showed stable placement of the watchman flx closure device with no thrombus, leaks, or pe.Accordingly, the decision was made to stop apixaban and to start clopidogrel for a total of 6 months post procedure.Five months after implantation, the patient presented with chest pain and shortness of breath.A transthoracic echocardiogram revealed a small to moderate pe without signs of tamponade.The watchman flx closure device remained stable with no complications, and the patient was diagnosed with pericarditis and treated as per guidelines before being discharged.Six months post implantation, repeat transesophageal echocardiogram revealed a thrombus on the epicardial aspect of laa and a large posterior pericardial effusion.The patient subsequently underwent surgical removal of both the laa and the protruding watchman flx closure device.The patient was discharged to a skilled nursing facility for recovery.He was then sent home with no complications.He was seen in the clinic and was doing well with no recurrent dyspnea or chest pain.
Additional Manufacturer Narrative
B3.Date of event: estimated as 11/19/2025 as the published date for the article is noted as 19 november 2025.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: darwish, o, ghanta, s, randhawa, s.Et al.Late-onset pericardial effusion and device extrusion after left atrial appendage occluder implantation.J am coll cardiol case rep.2025 nov, 30 (37).Https://doi.Org/10.1016/j.Jaccas.2025.105726.
Additional Manufacturer Narrative
H6: patient code e0604 added.
Event or Problem Description
Reported via journal article.It was reported a pericardial effusion occurred.A left atrial appendage (laa) closure procedure was performed, and a 35mm watchman flx closure device was implanted.The procedure was uneventful, and the patient was discharged home on apixaban and aspirin.A transesophageal echocardiogram (tee) performed during the procedure confirmed successful device placement without any pericardial effusion (pe).A repeat tee 45 days later showed stable placement of the watchman flx closure device with no thrombus, leaks, or pe.Accordingly, the decision was made to stop apixaban and to start clopidogrel for a total of 6 months post procedure.Five months after implantation, the patient presented with chest pain and shortness of breath.A transthoracic echocardiogram revealed a small to moderate pe without signs of tamponade.The watchman flx closure device remained stable with no complications, and the patient was diagnosed with pericarditis and treated as per guidelines before being discharged.Six months post implantation, repeat transesophageal echocardiogram revealed a thrombus on the epicardial aspect of laa and a large posterior pericardial effusion.The patient subsequently underwent surgical removal of both the laa and the protruding watchman flx closure device.The patient was discharged to a skilled nursing facility for recovery.He was then sent home with no complications.He was seen in the clinic and was doing well with no recurrent dyspnea or chest pain.

• 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: 23973784
• Report Number: 2124215-2026-00586
• Device Sequence Number: 13441069
• Product Code: NGV
• UDI-Device Identifier: 08714729860525
• UDI-Public: (01)08714729860525
• Combination Product (Y/N): N
• Initial Reporter State: AR
• Initial Reporter Country: US
• 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: Literature,Health Professional
• Initial Reporter Occupation: Physician
• Type of Report: Initial,Followup
• Report Date (Section B): 01/29/2026

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: 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: 12/22/2025
• Supplement Date Received by Manufacturer: 01/28/2026
• Initial Report FDA Received Date: 01/06/2026
• Supplement Report FDA Received Date: 01/29/2026
• 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; Hospitalization
• Patient Age: 74 YR
• Patient Sex: Male