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

Model Number	M635WU60400
Medical Device Problem Codes	Use of Device Problem (1670); Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Thrombosis/Thrombus (4440)
Date of Event	12/15/2025
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported that thrombosis occurred.A left atrial appendage (laa) closure procedure was performed using transesophageal echocardiogram (tee) imaging.A watchman fxd double curve access system (was) was inserted and advanced along with a 40mm watchman flx pro closure device and delivery system (wds) which was inserted and deployed in the laa.A partial recapture was performed three times to optimize positioning.During the fourth deployment, tee at 90 degrees and 135 degrees demonstrated approximately one-third protrusion on the inferior and posterior aspect; however, anchor stability, device sizing, and seal were acceptable, and overall device frame contact within the laa appeared appropriate.During this release criteria assessment, hazy echo was noted within the closure device, and a thrombus-like finding measuring approximately 13.7 mm by 8 mm was visualized at the threaded insert/screw region.The activated clotting time (act) at that time was 275 seconds.Additional heparin was administered, and aspiration was performed through the wds with the core wire connected.Approximately 150 cc of blood was aspirated, and several large clots were retrieved.Repeat tee imaging demonstrated no significant residual thrombus at the screw site, and due to the desire to minimize left atrial dwell time, the closure device was released and implanted.At this time, a string like thrombus measuring approximately 7 mm in length was visualized adjacent to the closure device on tee.Heparin therapy was continued with a subsequent act of 374 seconds.The procedure was concluded.The patient remained neurologically intact post-procedure and is being observed.No patient adverse event occurred.
Event or Problem Description
It was reported that thrombosis occurred.A left atrial appendage (laa) closure procedure was performed using transesophageal echocardiogram (tee) imaging.A watchman fxd double curve access system (was) was inserted and advanced along with a 40mm watchman flx pro closure device and delivery system (wds) which was inserted and deployed in the laa.A partial recapture was performed three times to optimize positioning.During the fourth deployment, tee at 90 degrees and 135 degrees demonstrated approximately one-third protrusion on the inferior and posterior aspect; however, anchor stability, device sizing, and seal were acceptable, and overall device frame contact within the laa appeared appropriate.During this release criteria assessment, hazy echo was noted within the closure device, and a thrombus-like finding measuring approximately 13.7 mm by 8 mm was visualized at the threaded insert/screw region.The activated clotting time (act) at that time was 275 seconds.Additional heparin was administered, and aspiration was performed through the wds with the core wire connected.Approximately 150 cc of blood was aspirated, and several large clots were retrieved.Repeat tee imaging demonstrated no significant residual thrombus at the screw site, and due to the desire to minimize left atrial dwell time, the closure device was released and implanted.At this time, a string like thrombus measuring approximately 7 mm in length was visualized adjacent to the closure device on tee.Heparin therapy was continued with a subsequent act of 374 seconds.The procedure was concluded.The patient remained neurologically intact post-procedure and is being observed.No patient adverse event occurred.
Additional Manufacturer Narrative
H6 device code corrected from use of device problem to adverse event without identified device or use problem - as it was incorrectly coded initially.

• 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: 23863083
• Report Number: 2124215-2025-92249
• Device Sequence Number: 13114012
• Product Code: NGV
• UDI-Device Identifier: 00191506004637
• UDI-Public: (01)00191506004637(17)270502(10)33955738
• Combination Product (Y/N): N
• Initial Reporter Country: JA
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2025
• 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): 02/20/2026

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: 0033955738
• 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: 12/15/2025
• Supplement Date Received by Manufacturer: 02/19/2026
• Initial Report FDA Received Date: 12/22/2025
• Supplement Report FDA Received Date: 02/20/2026
• Date Device Manufactured: 05/02/2024
• 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
• Patient Age: 73 YR
• Patient Sex: Male