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	Low Blood Pressure/ Hypotension (1914); Cardiac Tamponade (2226); Pericardial Effusion (3271)
Date of Event	03/02/2026
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported a pericardial effusion occurred.A left atrial appendage closure (laac) procedure was being performed.Prior to the procedure, a trivial pericardial effusion was noted at baseline on imaging.A watchman access system (was) and a 20mm watchman flx pro laa closure device & delivery system (wds) were selected for use.The transseptal puncture (tsp) was performed and was noted to be difficult due to a thick septum.The 20mm wds was deployed in the laa.Imaging was difficult to view in the mitral view.While repositioning for a higher angle, it was noted that there was fluid around the left ventricle (lv).The patient blood pressure was checked and noted to be 65 systolic.A pericardial tap kit was prepared, and a transthoracic echocardiogram (tte) was taken.A pericardial effusion was noted on both the lv and right ventricle (rv).Approximately 1l of blood was drained to treat the effusion.The patient stabilized after 60 ml protamine was administered and 1000ml of blood was drained.The blood was transfused back into the patient.Tte showed improvement of the effusion and the patient blood pressure stabilized at 120 systolic.The patient was monitored for 15 minutes.Transesophageal echocardiography (tee) confirmed the closure device was in a stable position and meeting position, anchor, size and seal (pass) criteria.The closure device was released.The patient was sent to the intensive care unit (icu) for recovery and was scheduled to receive an additional two units of blood later.There were no further complications and the patient was discharged.
Additional Manufacturer Narrative
The device was not returned for analysis as the device remains implanted; 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.
Event or Problem Description
It was reported a pericardial effusion occurred.A left atrial appendage closure (laac) procedure was being performed.Prior to the procedure, a trivial pericardial effusion was noted at baseline on imaging.A watchman access system (was) and a 20mm watchman flx pro laa closure device & delivery system (wds) were selected for use.The transseptal puncture (tsp) was performed and was noted to be difficult due to a thick septum.The 20mm wds was deployed in the laa.Imaging was difficult to view in the mitral view.While repositioning for a higher angle, it was noted that there was fluid around the left ventricle (lv).The patient blood pressure was checked and noted to be 65 systolic.A pericardial tap kit was prepared, and a transthoracic echocardiogram (tte) was taken.A pericardial effusion was noted on both the lv and right ventricle (rv).Approximately 1l of blood was drained to treat the effusion.The patient stabilized after 60 ml protamine was administered and 1000ml of blood was drained.The blood was transfused back into the patient.Tte showed improvement of the effusion and the patient blood pressure stabilized at 120 systolic.The patient was monitored for 15 minutes.Transesophageal echocardiography (tee) confirmed the closure device was in a stable position and meeting position, anchor, size and seal (pass) criteria.The closure device was released.The patient was sent to the intensive care unit (icu) for recovery and was scheduled to receive an additional two units of blood later.There were no further complications and the patient was discharged.

• 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: 24524327
• Report Number: 2124215-2026-12381
• Device Sequence Number: 18573006
• Product Code: NGV
• UDI-Device Identifier: 00191506004583
• UDI-Public: (01)00191506004583(17)280910(10)37435660
• Combination Product (Y/N): N
• Initial Reporter State: MI
• Initial Reporter Country: US
• PMA/510(K) Number: P130013
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2026
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Health Professional,Company Representative
• Initial Reporter Occupation: Physician
• Type of Report: Initial,Followup
• Report Date (Section B): 04/15/2026

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: 0037435660
• 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: 03/02/2026
• Supplement Date Received by Manufacturer: 04/02/2026
• Initial Report FDA Received Date: 03/05/2026
• Supplement Report FDA Received Date: 04/15/2026
• Date Device Manufactured: 09/11/2025
• 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: Hospitalization; Required Intervention
• Patient Age: 78 YR
• Patient Sex: Female
• Patient Race: White