MAUDE Adverse Event Report: BOSTON SCIENTIFIC CORPORATION WATCHMAN FXD Curve? Access System; system, appendage closure, left atrial

Model Number	M635TU80020
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Code	Thrombosis/Thrombus (4440)
Date of Event	09/23/2026
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported thrombosis occurred.A left atrial appendage closure (laac) procedure was being performed.A watchman fxd double curve access system (was) and a 24mm watchman flx pro laa closure device and delivery system (wds) was selected for use.Transseptal puncture was successfully completed, and the activated clotting time (act) was 373 seconds.The was was inserted, and a 24mm wds was advanced and deployed.After assessment, the 24mm wds was determined to be undersized.The device was recaptured, removed, and exchanged for a larger 27mm wds.As the 27 mm wds was introduced through the was, transesophageal echocardiography (tee) revealed a long, fibrous clot within the left atrial appendage.The 27mm wds was removed from the sheath, and the physician aspirated 30ml of blood through the was.Following aspiration, the clot was no longer visualized on tee; however, no clot was identified in the aspirated blood.The physician then reintroduced and began advancing the same wds.As the device approached the tip of the was sheath, the same fibrous clot was again observed on tee.The device was removed, and aspiration was repeated, this time with 50ml of blood.The clot again disappeared from tee but was not identified in the aspirated blood.It was suspected that the clot was attached to the tip of the sheath, so the was was removed and replaced with a new was, and a new wds was selected.Despite these measures, the same fibrous clot was again visualized on tee.Given the recurrent appearance of the clot and in the interest of patient safety, the procedure was aborted.The plan is to reattempt the procedure in approximately two months.The patient was discharged the next day.

• Brand Name: WATCHMAN FXD Curve? Access System
• 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; multitenant #2, street #58 zon; cartago, 03 30106 ; CS 30106
• Manufacturer Contact: mary crawford ; 4100 hamline ave n; arden hills, MN 55112 ; +1(651)440-0979
• MDR Report Key: 50932308
• Report Number: 2124215-2026-51651
• Device Sequence Number: 16137243
• Product Code: DQY
• UDI-Device Identifier: 00191506013813
• Combination Product (Y/N): N
• Initial Reporter State: OR
• Initial Reporter Country: US
• PMA/510(K) Number: K212228
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Health Professional,Company Representative
• Initial Reporter Occupation: Physician
• Type of Report: Initial
• Report Date (Section B): 09/29/2026

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: M635TU80020
• Device Catalogue Number: M635TU80020
• Device Lot Number: 0038903121
• 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: 09/23/2026
• Initial Report FDA Received Date: 09/29/2026
• Date Device Manufactured: 03/23/2026
• 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: Other
• Patient Age: 80 YR
• Patient Sex: Male