Embolization for Arteriovenous Malformation (AVM)
Fellowship-trained cerebrovascular neurosurgeons • 12 hospital affiliations across New JerseyAVM embolization is an endovascular procedure in which a liquid embolic agent or coils are injected through a microcatheter directly into the feeding arteries of a brain arteriovenous malformation (AVM), reducing blood flow through the abnormal vessels. It is most commonly used as a pre-surgical or pre-radiosurgery adjunct to reduce AVM size and bleeding risk, though small AVMs can occasionally be cured with embolization alone.
Key takeaways
- An arteriovenous malformation (AVM) is a tangle of abnormal blood vessels that connects arteries directly to veins without a normal capillary bed, creating a lifelong risk of bleeding.
- Embolization uses liquid embolic agents or coils delivered through a microcatheter to reduce or eliminate blood flow to the AVM.
- It is most commonly performed before microsurgery or stereotactic radiosurgery to improve the safety and effectiveness of definitive treatment.
- For carefully selected small, simply configured AVMs, embolization alone may achieve complete obliteration.
- Atlantic Brain and Spine's multidisciplinary cerebrovascular team develops an individualized treatment plan that may include embolization, microsurgery, stereotactic radiosurgery, or a combination of these approaches.
| Procedure type | Endovascular embolization of AVM feeding arteries |
| Purpose | Reduce blood flow before microsurgery or stereotactic radiosurgery; occasionally curative for selected small AVMs |
| Embolic agents | Onyx (EVOH), n-BCA glue, coils (selected cases) |
| Anesthesia | General anesthesia |
| Sessions required | One to three sessions depending on AVM size and complexity |
| Hospital stay | Typically one to two nights per treatment session |
| Role in treatment | Most commonly performed as part of a multidisciplinary treatment plan |
Timing and stay vary by patient and complexity. Your surgeon will confirm what to expect in your case.
What is a brain AVM?
An arteriovenous malformation (AVM) is a tangle of abnormal blood vessels in which arteries connect directly to veins without a normal capillary network in between. In the brain, this abnormal connection creates high-pressure, high-flow shunting from the arterial to the venous circulation, placing the thin-walled veins under arterial pressure.
The primary risk of a brain AVM is hemorrhage. If an AVM ruptures, it can cause bleeding into the brain, resulting in stroke, permanent neurological deficits, or death. The annual risk of hemorrhage for an unruptured brain AVM is approximately 2% to 4%, although the risk varies depending on the AVM’s size, location, and other characteristics. AVMs can also cause seizures, headaches, or progressive neurological deficits due to vascular steal, in which blood is diverted away from surrounding normal brain tissue.
How AVM embolization is performed
Under general anesthesia, a microcatheter is navigated from the femoral or radial artery to the arteries supplying the AVM. The catheter is advanced as close as possible to the AVM nidus the core of the abnormal blood vessel tangle. A liquid embolic agent, most commonly Onyx, is then injected slowly while blood flow is monitored using real-time fluoroscopy. The embolic material hardens within the abnormal vessels, blocking blood flow to the AVM.
The goal of embolization is to reduce blood flow to the AVM and, when appropriate, decrease the size or complexity of the malformation before definitive treatment. By reducing blood flow through the nidus, embolization may decrease operative blood loss, improve visualization during microsurgery, or increase the effectiveness of stereotactic radiosurgery. In carefully selected patients with small, favorable AVMs, embolization alone may achieve complete obliteration.
Multimodal AVM treatment
Most brain AVMs are treated using a multimodal approach tailored to the AVM’s size, location, and anatomy:
- Embolization + microsurgical resection: Preoperative embolization reduces blood flow to the AVM before surgical removal of the nidus. This approach is preferred for many accessible AVMs when complete cure is the goal.
- Embolization + CyberKnife radiosurgery: For AVMs in deep or eloquent brain regions where surgery carries higher risk, embolization may reduce the size or blood flow of the nidus before CyberKnife treatment in appropriately selected patients.
- Embolization alone: In selected small, simply configured AVMs with a limited number of feeding vessels, embolization alone may achieve complete obliteration, which is confirmed with follow-up catheter angiography.
Benefits and risks
Potential benefits
- Reduces blood flow to the AVM, making microsurgery or radiosurgery safer and more effective.
- May achieve complete obliteration in selected small AVMs without open surgery.
- Minimally invasive, catheter-based procedure performed through the groin or wrist.
- Reduces blood loss and facilitates microsurgical resection when used before surgery.
Possible risks
- Stroke if embolic material inadvertently blocks a normal brain artery risk minimized through detailed imaging, careful catheter positioning, and continuous fluoroscopic guidance.
- Rare risk of AVM rupture during embolization due to changes in blood flow or vessel pressure.
- Temporary or permanent neurological deficits if normal brain tissue is affected by the procedure.
- Partial embolization may change blood flow within the AVM, sometimes requiring additional embolization, surgery, or radiosurgery to complete treatment.
Your surgeon will review the benefits and risks specific to your diagnosis during your consultation.
What recovery looks like
Recovery after AVM embolization depends on the size and location of the AVM, the extent of embolization performed, and whether additional treatment is planned.
- Day of procedure Recovery in a monitored setting for several hours followed by overnight neurological observation. The groin or wrist access site is monitored closely.
- Days 1 to 2 Most patients are discharged after a stable neurological examination. Avoid strenuous activity and heavy lifting while the arterial access site heals.
- Between sessions If staged embolization is planned, light activity may be resumed as directed. Most patients return to normal daily activities within 1 to 2 weeks after each treatment session.
- After definitive treatment Recovery depends on the final stage of treatment. Patients undergoing stereotactic radiosurgery typically resume normal activities quickly, while recovery after microsurgical resection is generally longer and depends on the complexity of surgery.
Frequently asked questions
Can embolization alone cure an AVM?
Sometimes. In carefully selected patients with small, compact AVMs supplied by only a few feeding arteries, embolization alone may completely obliterate the AVM. However, most AVMs are too large or complex to be cured with embolization alone and require additional treatment with microsurgery or CyberKnife radiosurgery. Follow-up catheter angiography is performed to confirm whether the AVM has been completely eliminated.
How many embolization sessions are needed?
Most AVMs require 1 to 3 embolization sessions before definitive surgery or radiosurgery, spaced 2 to 4 weeks apart. Very small AVMs may be cured in a single session.
Will I still need surgery or radiosurgery after embolization?
Usually, yes. Embolization is most often performed to reduce blood flow to an AVM before definitive treatment with microsurgery or stereotactic radiosurgery. By decreasing the size, complexity, or blood supply of the malformation, embolization can improve the safety and effectiveness of subsequent treatment. In carefully selected patients with small, favorable AVMs, embolization alone may completely eliminate the AVM. Follow-up catheter angiography is used to determine whether additional treatment is necessary.
What is the cure rate for AVM radiosurgery after embolization?
CyberKnife or Gamma Knife achieves complete AVM obliteration in approximately 75 to 90% of cases when the nidus volume is under 10 cc. Obliteration takes 2 to 3 years after radiosurgery, during which the AVM still carries hemorrhage risk.
This page is for general education and does not replace medical advice. Treatment decisions should be made with a qualified neurosurgeon based on your individual diagnosis and imaging. To discuss your options, call Atlantic Brain and Spine Vascular Neurosurgical Care at 973.993.7100 or request a consultation.
Neurovascular Specialists at Atlantic Brain and Spine
Your care is provided by Atlantic Brain and Spine's multidisciplinary cerebrovascular team, including fellowship-trained cerebrovascular and endovascular neurosurgeons.
