Recovery Outlook for Arteriovenous Malformation

Arteriovenous malformations (AVMs) are abnormal blood vessels with improper artery-to-vein connections. Most people do not experience symptoms until the AVM ruptures.

Fortunately, AVMs can be cured through surgery, sometimes in combination with other treatment options such as endovascular embolization and radiosurgery. Learn more about the recovery outlook of AVMs below.

AVM treatment options include surgery, endovascular embolization, and/or radiosurgery. The decision to pursue one treatment option over another is dependent on characteristics of the patient and the AVM. Prevention of AVM rupture is the primary goal of treatment, but the risk of AVM rupture is different for each patient.

The likelihood of AVM rupture is 2 – 4% each year, though this is higher in AVMs with associated aneurysms, AVMs located deep within the brain, or those with only a single draining vein.

The risk of rupture without treatment must be weighed against the risk of sustaining neurological complications following intervention.

Risks of surgery can be predicted by the grade of an AVM. A low grade AVM is typically smaller and/or located closer to the surface of the brain, allowing for easier and safer surgery with better outcomes.

Endovascular embolization and radiosurgery are other treatment options that may be used in combination with surgery to facilitate complete removal or can be used alone if surgery is too risky. Each treatment is further described below.

Surgery: The AVM is surgically removed, and blood flow is rerouted to healthy vessels. Because AVMs do not usually regrow, complete removal of the AVM results in an immediate and permanent cure.

AVMs positioned in deep areas of the brain pose higher risks for neurological complications following surgical removal and may not be amenable to safe resection.

Incomplete removal of AVMs is not safe and is associated with a higher risk of subsequent hemorrhage.

Embolization: Endovascular embolization is a minimally invasive approach that involves inserting a tiny flexible tube (catheter) into the groin. The catheter is advanced up to the blood vessels involved in the AVM.

A special glue is released which quickly solidifies and blocks off blood flow to the AVM. This may be performed prior to surgery to occlude deep AVM blood vessels that are difficult to surgically reach.

Radiosurgery: Despite having “surgery” in its name, radiosurgery is actually just a type of radiation therapy that uses targeted radiation beams to shrink, scar, and eventually choke off blood flow to the AVM over a period of time.

This can close off a small AVM in two to three years. It is important to note that during these few years, the AVM is still present and thus still has a risk of rupture. Cure rates vary with radiosurgery alone and radiosurgery is typically used if surgery is not feasible.

Another alternative is to simply observe the AVM. Observation may be favorable if interventional treatment is far too risky, or if an AVM is found at an older age and does not cause symptoms.

For older patients, the cumulative lifetime risk of rupture is lower than that of a younger patient. A thorough discussion of the risks and benefits of each treatment option is critical to determine which option will be best for you.

Arteriovenous malformation prognosis can vary depending on whether the AVM was found before or after rupture and what types of treatment methods were used.

Untreated AVM has a poor prognosis due to the aforementioned risk of bleeding (2 – 4% each year). This means the longer an AVM goes untreated, the greater the chance of a bleed occurring. Even if an AVM does not rupture, it could result in symptoms such as headaches, seizures and cognitive decline caused by increased pressure from abnormal blood flow to the brain. As such, it is crucial for patients with AVM to seek medical evaluation and appropriate treatment to manage their condition and reduce the risk of complications.

Advances in medical and surgical treatments have significantly improved the outlook of patients suffering from AVMs. Upon AVM rupture, most individuals will survive.

However, death can occur in up to 10% of patients, and 10 – 20% of patients may suffer from severe neurological disabilities that interfere with everyday functioning.

After the initial hemorrhage, the risk of another hemorrhage increases to approximately 6 – 15% in the first year, if the AVM is left untreated. Additionally, a fifth of patients may develop recurrent seizures (epilepsy) later in life.

Prevention of AVM rupture and these potential neurological complications is the primary goal of treatment. However, treatment comes with its own risks.

In general, all treatment options have low neurological complication (morbidity) rates of less than 10% and very low death (mortality) rates of 1 – 2%.

When comparing treatment methods in isolation, surgery offers the best chance of a cure. Other treatment options are typically used in combination with surgery to facilitate complete removal or are considered if surgery is not feasible or safe.

• After surgery, morbidity and mortality rates are 5% and less than 1%, respectively. The average cure rate is over 95%, and less than 1% of patients experience another bleed after the operation.
• After endovascular embolization, morbidity and mortality rates are 6% and 2%, respectively. The average cure rate is 30% and less than 10% of patients experience another bleed after the operation.
• After radiosurgery, morbidity and mortality rates are 7% and 1%, respectively. The average cure rate is 75%, and 7% of patients experience another bleed after the operation.   

These reported rates are more representative of treatment for low-grade AVMs and do not consider AVM prognosis for cases where different treatment methods are used in combination.

Higher rates of morbidity and mortality may be present for AVMs that are large, located deep within the brain, or neighbor critical brain regions. Although these numbers provide a useful reference to calculate risk, it is important to note that there are numerous other factors to account for when weighing the risks and benefits of treatment.

After surgery, an angiogram will be performed to ensure that no blood is flowing through the AVM. This indicates that the AVM has been effectively cured and removed from normal circulation.

Immediately after surgery, you will be taken to the intensive care unit (ICU) and likely spend a few days in the hospital for monitoring. During this time, you may also undergo rehabilitation to facilitate AVM recovery. Rehabilitation will help you regain strength, mobility, language, and other functions as needed.

For about a week after surgery, your scalp incision may be sore. Numbness surrounding the incision and swelling, and bruising around the eyes are possible side effects.

As the incision begins to heal, it may itch. Headaches, discomfort, swelling, and itching can be alleviated with pain-relief medications and ice packs. It is common to feel more weary than usual for several weeks as your body recovers.

After 4 to 6 weeks, you may feel ready to resume most of your normal activities. However, full AVM recovery will likely take 2 to 6 months.

Patients who have undergone surgical removal of their AVMs before they rupture can expect a return to their everyday activities and have a normal life. This is particularly true for younger patients.

Fortunately, most patients survive even if their AVMs rupture. Direct death related to AVM rupture has been reported to occur in up to 10% of patients, though more recent studies estimate lower rates of 1 – 2%.

A subset of patients (10 – 20%) experience severe neurological deficits that impair everyday activities and may even go on to develop recurrent seizures (epilepsy) later in life. AVM rupture can be life-threatening and cause neurological consequences. Thus, while AVM prognosis for most patients is positive, with successful treatment leading to a normal lifespan, it's crucial to acknowledge these potential long-term complications of a rupture. As such, prevention of rupture is the primary goal of treatment.

Overall, AVM prognosis is favorable with appropriate management. Although AVM rupture can be life threatening, most individuals survive. Surgery provides excellent cure rates, especially for low-grade AVMs. All treatment options have low morbidity and mortality rates and may be used in combination to successfully manage the AVM.

● AVMs can be cured through surgery.

● It can take up 2 to 6 months to fully recover after surgery for AVM removal.

● More than 90% of people who have an AVM bleed survive the incident.

● In general, AVM prognosis is good with proper evaluation and expert treatment.

• The Aneurysm and AVM Foundation 
• AVM Research Foundation
• Brain Aneurysm Foundation 
• Child Neurology Foundation 
• National Institute of Neurological Disorders and Stroke