The purpose of this study is to evaluate the safety of the Apollo™ Onyx™ Delivery Microcatheter used for delivery of the Onyx™ Liquid Embolic System during brain arteriovenous malformation (AVM) embolization procedures.

This study is a prospective, single-arm, multicenter, post-market safety evaluation of subjects indicated for embolization of brain AVMs with the study device. The study device was developed to potentially minimize the side effects of catheter retainment and increased procedural risk associated with alternative methods necessary for removing entrapped catheters. In the event of catheter retainment, using the Apollo™ Onyx™ Delivery Microcatheter versus any a standard catheter represents leaving behind a 1.5 - 3.0 cm long detachable tip in the Onyx™ Onyx™ Delivery Microcatheter cast versus an average 165 cm long catheter in the vasculature.

Inclusion Criteria:

• The Subject or Subject's legally authorized representative has signed and dated an informed consent form.
• The Subject has a confirmed diagnosis of a brain AVM.
• The Subject is clinically and neurologically stable for a minimum of 48 hours prior to embolization.
• The Subject has a life expectancy of at least 1 year.
• The Subject agrees to and is capable of completing all study-required procedures.

Exclusion Criteria:

• Current participation in another investigational drug or device study that evaluates treatments for brain AVMs or other cerebrovascular disease.
• The Subject has a bleeding disorder.
• The Subject is not a candidate for the use of vasodilators.

Generally we do not plan to share the IPD. Researchers can contact the Sponsor if interested.

Adverse events were collected from the point of enrollment in the study until a subject exited the study (at 30-days or 12-months)

The adverse event data was adjudicated by a three member independent Clinical Events Committee (CEC). All data presented within this section has been CEC adjudicated. Adjudicable events met the following criteria:

• All Serious Adverse Events (SAEs)
• All device-related Adverse Events
• All procedure-related Adverse Events
• All AEs with an underlying neurological cause (neurological adverse event)

Study was completed.