MAUDE Adverse Event Report: MICROVENTION, INC. WEB; INTRASACCULAR FLOW DISRUPTION DEVICE

Model Number	W5-4.5-2-MVI-3
Medical Device Problem Code	Adverse Event Without Identified Device or Use Problem (2993)
Health Effect - Clinical Codes	Aneurysm (1708); Muscle Weakness/Atrophy (1967)
Date of Event	03/31/2026
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
Investigation findings: without the return and physical evaluation of the device, the investigation cannot further examine if a condition existed that would have contributed to the reported event.Without imaging, the investigation cannot further verify if the event occurred as described, nor could the investigation further evaluate the cause of the reported event.Based on a review of the device¿s risk documentation, the reported event did not indicate there were the presence of any potential or new manufacturing, design, quality, or other systemic issues, or non-conformances.The complaint code is monitored through the trending process; corrective action is determined, as needed, through this process.Investigations of historic complaint files with similar complaint category coding are recorded in the complaint handling system; without the ability to perform an analysis of the device, this investigation cannot identify with certainty any potential root causes.Batch review: a search for non-conformances associated with this part/lot number combination did not reveal any production-related issues relevant to the complaint that occurred during manufacturing of the device.Complaint system review: there are no similar complaints based on the complaint category regarding this batch number from the last two years recorded in the complaint system at the time of this investigation.Ifu review (additional information can be found in the ifu): potential complications: potential complications include but are not limited to the following: vessel puncture site hematoma, aneurysm perforation or rupture, hemorrhage, edema, thromboemboli, transient ischemic attack, ischemic stroke, neurologic deficits, parent artery occlusion, ischemia, vessel dissection or perforation, vascular thrombosis, vasospasm, device migration or misplacement, premature detachment, headache, post-embolization syndrome, infection and death.Warnings: advance and retract the web embolization device slowly.Do not advance the delivery device with excessive force.Determine the cause of any unusual resistance.Remove the web embolization device if excessive friction is noted and check for damage.Do not rotate the delivery device during or after delivery of the web embolization device.Rotating the web embolization device may result in damage or premature detachment.The web embolization device cannot be detached with any other power source other than a web detachment control device.Ensure that at least two web detachment control devices are available before initiating an embolization procedure.Instructions for use: detachment of the web embolization device: 34.The detachment control device is pre-loaded with batteries and will activate when the delivery device is properly connected.35.Verify that the rhv is firmly locked around the delivery device before attaching the detachment control device to ensure that the web embolization device does not move during the connection process.36.Ensure that the delivery device gold connectors are clean and free from blood or contrast.If necessary, wipe the connectors with sterile water and dry before connecting.37.Insert the proximal end of the delivery device into the detachment control device.When the delivery device is properly connected, the light will flash green and an intermittent tone will be heard.38.Verify the web embolization device position before pressing the detachment button.39.Push the detachment button.During firing, the light should be solid green and the beep should be continuous.40.Verify detachment by first loosening the rhv valve, then pulling back slowly on the delivery device and verifying that there is not web embolization device movement.If the web embolization device does not detach, push the detachment button again.If the web embolization device is still not detached, obtain a new detachment control device and attempt detachment up to two additional times.If it does not detach, remove the delivery device.41.Verify the position of the web embolization device angiographically through the guide catheter.42.Prior to removing the microcatheter from the treatment site, place an appropriately sized guidewire completely through the microcatheter lumen to ensure that no part of the web embolization device remains within the microcatheter.Investigation conclusion: the physical device was not available for evaluation to investigate if a condition existed that would have contributed to the reported event.Supplemental imaging was also unavailable for review; without imaging, the investigation cannot verify the event occurred as described, nor could the investigation further examine the cause of the reported event.This study is ongoing and device/procedure relatedness determinations can be re-adjudicated by independent reviewers/physicians.The study device and study procedure relatedness can change as a result of these reviews.Microvention is submitting this report to comply with fda reporting regulations under 21 cfr parts 4 and 803.This report is based upon information obtained by microvention, which the company may not have been able to fully investigate or verify prior to the date the report was required by the fda.Microvention has made reasonable efforts to obtain more complete information and has provided as much relevant information as is available to the company as of the submission date of this report.This report does not constitute an admission or a conclusion by fda, microvention, or its employees that the device, microvention, or its employees caused or contributed to the event described in the report.This statement should be included with any information or report disclosed to the public under the freedom of information act.Any required fields that are unpopulated are blank because the information is currently unknown or unavailable.A good faith effort will be made to obtain the applicable information relevant to the report.
Event or Problem Description
As reported through the complex aneurysm registry (car): a patient with a history of hypertension who presented with a severe headache on the morning of admission and was found to have a diffuse subarachnoid hemorrhage.On arrival, patient was noted to be drowsy, and repeat imaging demonstrated hydrocephalus.Cta revealed a right mca aneurysm.The patient underwent successful evd placement and aneurysm embolization.Due to the wide-necked nature of the right mca aneurysm, web embolization with stent assistance was performed.However, on routine follow-up angiography, the aneurysm remained significantly patent, and a second embolization attempt with coils was performed twelve days post-index procedure.The patient did well post-op.On the thirteenth day post-index procedure, the patient developed acute weakness in the left upper extremity along with a decreased level of consciousness.A non-contrast ct head (cth) was negative for new hemorrhage, and clinical vasospasm was considered in the differential diagnosis.A cerebral angiogram with intra-arterial treatment for vasospasm was recommended.Preoperative diagnosis: symptomatic vasospasm after aneurysmal subarachnoid hemorrhage.Postoperative diagnosis: 1.Moderate vasospasm of right a1 artery and moderate vasospasm of right middle cerebral artery territory distal branches.2.Status post infusion of 15 mg of verapamil in the right ica.3.Moderate vasospasm of the left a1 and moderate distal mca territory status post 10 mg intraarterial verapamil into the left ica.Patient current condition: no discharge note is available.Hospitalization status is unknown.

• Brand Name: WEB
• Common Device Name: INTRASACCULAR FLOW DISRUPTION DEVICE
• Manufacturer (Section D): MICROVENTION, INC.; 35 enterprise; aliso viejo CA 92656
• Manufacturer Contact: terrence callahan ; 35 enterprise; aliso viejo, CA 92656 ; 7142478000
• MDR Report Key: 24955822
• Report Number: 2032493-2026-00270
• Device Sequence Number: 10029913
• Product Code: OPR
• UDI-Device Identifier: 00842429110799
• UDI-Public: 00842429110799
• Combination Product (Y/N): N
• Initial Reporter State: FL
• Initial Reporter Country: US
• PMA/510(K) Number: P170032
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2026
• Serviced by Third Party (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Study,Health Professional,User Facility,Company Representative
• Initial Reporter Occupation: Physician
• Type of Report: Initial
• Report Date (Section B): 04/22/2026

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: W5-4.5-2-MVI-3
• Device Lot Number: 0000868553
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Was the Report Sent to FDA?: No
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 03/31/2026
• Initial Report FDA Received Date: 04/22/2026
• Was Device Evaluated by Manufacturer? (Y/N): No
• Date Device Manufactured: 01/14/2025
• 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; Required Intervention
• Patient Sex: Female