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

Model Number	M635WU60400
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Pericardial Effusion (3271)
Date of Event	03/04/2026
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported that pericardial effusion (pe) occurred.A left atrial appendage (laa) closure procedure was being performed.The laa anatomy was described as having a wide ostium with shallow depth.A 40mm watchman flx pro closure device and delivery system (wds) was inserted.Multiple deployment attempts of the wds were made using different access lobes in an effort to achieve a deployment that met release criteria; however, appropriate positioning and fixation could not be achieved.During recapture of the wds following the 19th deployment attempt, echocardiography demonstrated motion displacing the laa tissue and a pe was identified.The patient was monitored and imaging confirmed no further increase in pe fluid and no additional changes.The physician considered that the pe occurred during the final recapture attempt and cancelled the procedure as it was not possible to meet the release criteria and ensure fixation despite multiple attempts.
Event or Problem Description
It was reported that pericardial effusion (pe) occurred.A left atrial appendage (laa) closure procedure was being performed.The laa anatomy was described as having a wide ostium with shallow depth.A 40mm watchman flx pro closure device and delivery system (wds) was inserted.Multiple deployment attempts of the wds were made using different access lobes in an effort to achieve a deployment that met release criteria; however, appropriate positioning and fixation could not be achieved.During recapture of the wds following the 19th deployment attempt, echocardiography demonstrated motion displacing the laa tissue and a pe was identified.The patient was monitored and imaging confirmed no further increase in pe fluid and no additional changes.The physician considered that the pe occurred during the final recapture attempt and cancelled the procedure as it was not possible to meet the release criteria and ensure fixation despite multiple attempts.
Additional Manufacturer Narrative
The device was not returned for analysis as the device was discarded; 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: 24534659
• Report Number: 2124215-2026-12669
• Device Sequence Number: 15686837
• Product Code: NGV
• UDI-Device Identifier: 00191506004637
• UDI-Public: (01)00191506004637(17)281125(10)38052971
• 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,Health Professional,Company Representative
• Initial Reporter Occupation: Physician
• Type of Report: Initial,Followup
• Report Date (Section B): 04/24/2026

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: M635WU60400
• Device Catalogue Number: M635WU60400
• Device Lot Number: 0038052971
• 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: 03/04/2026
• Supplement Date Received by Manufacturer: 04/15/2026
• Initial Report FDA Received Date: 03/06/2026
• Supplement Report FDA Received Date: 04/24/2026
• Date Device Manufactured: 11/26/2025
• 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 Sex: Unknown