ev3 Onyx Liquid Embolic System


ev3 Onyx Liquid Embolic System: Safety Communication – Risk of Catheter Entrapment

AUDIENCE: Neurology, Surgery

ISSUE: FDA notified physicians and patients about the risk of catheter entrapment associated with the use of Onyx. Catheter entrapment happens when the catheter becomes stuck in the implanted Onyx material. The most serious complications include hemorrhage and death. Other complications include migration of the Onyx plug or catheter fragment to other parts of the body. Patients with catheter entrapment may need to take antithrombotic drugs to prevent blood clots around the catheter, and may need to undergo one or more imaging procedures to locate a piece of the catheter and Onyx plug, increasing their exposure to radiation.

The FDA approved changes to the physician and patient labeling that reflect the risks related to catheter entrapment. The labeling also includes recommendations to help minimize the risk of entrapment. Physicians should expect to see this labeling in new orders of Onyx. 

BACKGROUND: The Onyx Liquid Embolic System (“Onyx”), manufactured by ev3, is a liquid material used to block blood flow in abnormally formed blood vessels in the brain, also know as brain arteriovenous malformations or brain AVMs, before their surgical removal. A catheter is used to deliver the Onyx liquid to blood vessels in the brain. 

RECOMMENDATIONS: Catheter entrapment is unlikely to affect the physician’s ability to surgically remove the patient’s AVM. However, neither Onyx nor the catheter is intended to be long-term implants, and patients may need additional medical interventions to have the catheter removed if it becomes entrapped.

  • Neuro interventionalists should select patients carefully, after reviewing the most recent device labeling and instructions.
  • Onyx is only approved for use in patients who will undergo surgical removal of the treated brain AVM.
  • Onyx has not been tested or approved as a long-term implant.
  • Healthcare professionals should be prepared to treat serious complications associated with the use of Onyx and ensure that your facility is staffed and equipped to address these complications should they arise.

Read the FDA Safety Communication for additional information.

Prompt reporting of adverse events can help the FDA identify and better understand the risks associated with medical devices. If you suspect a problem with the Onyx Liquid Embolic System, including a difficult to remove or entrapped (retained) catheter while using Onyx, we encourage you to file a voluntary report through MedWatch, the FDA Safety Information and Adverse Event Reporting Program. Health care personnel employed by facilities that are subject to the FDA’s user facility reporting requirements should follow the reporting procedures established by their facilities.

Please include the following information in your reports, if available:

  • Adverse event details (date adverse event occurred; complications that occurred, e.g. retained or plugged catheter, migration of Onyx plug, hemorrhage of the brain AVM; and the medical intervention required)
  • Type of Onyx used (e.g. Onyx 18 or Onyx 34)
  • Expiration dates of Onyx, delivery catheter and all accessories used
  • Model and size of catheter used with Onyx
  • Location in the anatomy where Onyx was used
  • Amount (distance) of reflux
  • Whether vessel was in vasospasm
  • Whether surgical resection is planned
  • Location in the pedicle being embolized where the catheter got stuck. For example, proximity to the origin of the pedicle vessel and proximity to the Onyx plug.
  • Whether additional medical therapies (e.g. antithrombotics) were needed

To report adverse events or side effects related to the use of this product:

  • Complete and submit the report Online: www.fda.gov/MedWatch/report.htm
  • Download form or call 1-800-332-1088 to request a reporting form, then complete and return to the address on the pre-addressed form, or submit by fax to 1-800-FDA-0178

Read the MedWatch safety alert, including a link to the FDA safety communication, at:


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