The Silent Threat of AVMs
What happens when malformed blood vessels go undetected?
“Brain arteriovenous malformations (AVM) are a silent risk,” said Dr. Fady T. Charbel, an internationally recognized surgical expert and head of the Department of Neurosurgery at the University of Illinois Chicago (UIC). “People may go through life without symptoms, yet the consequences of rupture can be severe.”
Brain AVMs are clusters of malformed blood vessels that pose a risk of brain hemorrhage or seizures. Often, these malformations may not be discovered until a significant complication occurs, such as a hemorrhagic stroke. Brain AVMs make up a small percentage of hemorrhagic strokes each year. However, when left untreated, the annual risk of rupture is estimated at 2-4%, according to the National Institutes of Health (NIH).
While most strokes and hemorrhages affect older adults, on average, these malformations are a more common cause of brain hemorrhages in children and young adults.
At UIC, neurosurgeons employ advanced microsurgical and endovascular techniques to carefully manage complex brain AVMs. “When these malformations are detected, our team evaluates each case using a collaborative, multidisciplinary approach,” Dr. Charbel explained. “This allows us to reduce rupture risk while preserving healthy brain tissue and function for the most effective care possible.”
What is an AVM?
AVMs are abnormal tangles of blood vessels where arteries connect directly to veins, bypassing the small capillaries (the smallest vessels) that normally perfuse brain tissue.
In a healthy brain, blood flows like a river, moving freely downstream. But when rocks scatter the path, the proper flow is disrupted. Similarly, the tangled vessels prevent blood from flowing evenly, occasionally depriving surrounding brain tissue of oxygen while putting stress on the fragile vessels, making them prone to rupture.
While these malformations can develop throughout the body, those developed in the brain are especially threatening, since certain areas of the brain can be much more vulnerable to bleeding, leading to permanent brain damage.
According to the National Institute of Health:
Clinically known as ‘the silent disease,’ only 12% of AVMs are estimated to become symptomatic.
Why AVMs Often Go Undetected?
The cause of these vascular malformations remains unclear, though many researchers believe they form during fetal development. Because brain AVMs are often asymptomatic, they’re usually discovered incidentally on imaging for unrelated issues.
Subtle warning signs—such as chronic headaches, confusion, or seizures—can be easily mistaken for other common conditions, but these warning signs are all dependent on the size and location.
Brain AVMs are a notable cause of brain hemorrhage in children and young adults (ages 10–40), more so than in older adults.
“Unlike in older patients—where strokes and hemorrhages are often anticipated—bleeding in younger people is unexpected, making early recognition and treatment even more critical to prevent long-term neurological damage,” explained Dr. Ali Alaraj, Professor and Section Chief, Endovascular Neurosurgery at UIC. “This points to the importance of regular medical examination and early evaluation.”
Multidisciplinary Treatment at UIC
“What makes UIC stand out is our truly integrated, multidisciplinary approach,” says Dr. Gursant Atwal, an endovascular neurosurgeon who specializes in blood vessel disorders. “Every AVM case is reviewed by a team of specialists who bring their own expertise for the best outcome for the patient.”
At UIC, diagnosing and treating these malformations relies on a uniquely collaborative, multidisciplinary approach. Neurosurgeons, neuroradiologists, neurologists, endovascular neurosurgeons, and radiation oncologists work closely together to evaluate each patient’s condition from every angle to determine the best course of treatment.
Because AVMs often sit near areas of the brain responsible for movement or speech, every intervention requires precise planning and mapping to minimize risk.
Using Non-invasive Optimal Vessel Analysis (NOVA) software, developed by Dr. Charbel, the team can precisely measure blood flow in intracranial vessels—providing quantitative data that helps guide treatment decisions and assess rupture risk based on the AVM’s size, location, and hemodynamic profile.
This level of coordination allows experts at UIC to design highly individualized treatment plans—whether through observation or intervention.
Such interventions include a resection, which uses a high-powered microscope to seal off the tangled vessels with tiny clips to stop blood flow, then carefully separating it from the surrounding brain tissue. This is typically reserved for vascular tangles that can be removed with minimal risk of hemorrhage or seizure.
“When the tangles have developed to the point where they are at risk of hemorrhage, endovascular embolization can be a life-saving option,” says Dr. Atwal. “It’s a procedure we’ve continued to refine and specialize here at UIC.” During the procedure, a catheter is placed in one of the arteries that supply the brain AVM. An embolizing agent is then injected to block the artery and reduce blood flow to it. This targeted approach significantly lowers the risk of rupture and helps stabilize patients for further treatment if needed.
Dr. Charbel on UIC's Multidisciplinary approach
When these malformations are detected, our team evaluates each case using a collaborative, multidisciplinary approach. This allows us to reduce rupture risk while preserving healthy brain tissue and function for the most effective care possible.
The Department of Neurosurgery
The Department of Neurosurgery at UIC continues to deliver positive outcomes as one of the nation’s top centers by transforming patient care with innovation, precision, and collaboration. The team’s vast experience with cerebrovascular anatomy and function, as well as advanced imaging and surgical technology, provides each patient with the most informed, personalized care possible.