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 Codes	Pain (1994); Pericardial Effusion (3271)
Date of Event	08/18/2026
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported that pericardial effusion occurred.A left atrial appendage (laa) closure procedure was performed, and a 20mm watchman flx pro closure device was implanted.During the procedure, the patient was receiving antithrombotic therapy with plavix and aspirin (asa) per pre-procedure orders.Heparin was administrated and achieved an activated clotting time (act) of 436 seconds, which was higher than expected.A total of 7,000 units of iv heparin were administered, including 5,000 units prior to transseptal puncture (tsp) and an additional 2,000 units after tsp once the closure device was in the left atrium (la).The patient had pre-imaging via computed tomography (ct).The procedure was performed under conscious sedation using nurse-administered fentanyl and midazolam (versed), with guidance from mini transesophageal echocardiography (tee).The patient tolerated the procedure well and the total procedure time was 20 minutes.One deployment was performed with no recapture required.The position, anchor, size and seal (pass) criteria was met.No pericardial effusion was noted before or immediately after the procedure.During recovery, the patient complained of sharp pain with inhalation that was managed with medication.Electrocardiogram (ecg) findings remained unchanged, and vital signs were stable.A beside transthoracic echocardiogram (tte) was performed, and imaging showed a small effusion.The patient was stable and did not require pericardiocentesis.Discharged was planned for same day but the patient was admitted overnight for observation.A repeat tte showed a reduction in the size of the effusion.The patient was discharged the following day.

• 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 H91 Y 868; EI H91 Y868
• Manufacturer Contact: mary crawford ; 4100 hamline ave n; arden hills, MN 55112 ; +1(651)440-0979
• MDR Report Key: 50383799
• Report Number: 2124215-2026-45235
• Device Sequence Number: 14894348
• Product Code: NGV
• UDI-Device Identifier: 00191506004583
• UDI-Public: (01)00191506004583(17)270718(10)34459185
• Combination Product (Y/N): N
• Initial Reporter Country: CA
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2026
• Reporter Type: Manufacturer
• Report Source: Other,Foreign,Health Professional,Company Representative
• Initial Reporter Occupation: Physician
• Type of Report: Initial,Followup
• Report Date (Section B): 09/30/2026

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: 0034459185
• 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: Not provided
• Supplement Date Received by Manufacturer: 09/29/2026
• Initial Report FDA Received Date: 08/21/2026
• Supplement Report FDA Received Date: 09/30/2026
• Date Device Manufactured: 07/18/2024
• 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: Other; Hospitalization
• Patient Sex: Unknown