What Is An Arteriovenous Malformation?

So, you have an AVM. If you are like most of us, you never heard of an AVM until you found out you had one. Here is some information to help you navigate your AVM journey.

What is an AVM? An AVM (or arteriovenous malformation) is a congenital defect in the circulatory system, a malformation between an artery (or arteries) and a vein (or veins). There are other types of vascular anomalies that are similar to AVMs, such as cavernous malformations (CMs), venous malformations (VMs), or developmental venous anomalies (DVAs). If you have any of these, you are more than welcome here. If you have an aneurysm, you may wish to join our aneurysm community.

Some AVMs are hereditary, due to genetic conditions such as CM/AVM, HHT or Cowden Syndrome, and Cavernous malformations may also run in families. It is possible that all AVMs are due to genetic or inheritable factors – we don’t really know yet.

Why are AVMs a health issue? AVMs are problematic because the vessels may expand and become weakened and prone to rupture. In addition, because there are no capillaries in the malformation, the AVM may not allow nearby tissue to be properly nourished. In addition, AVMs may cause a variety of symptoms, depending on where they are located. Those in the brain may cause headaches, or a whooshing sound (bruit).

It is important to realize that some AVMs may never be symptomatic and may never become clinically significant, meaning they may never cause a problem. It is not accurate to say that all AVMs are “ticking time bombs,” and such catch phrases may cause patients undue anxiety. Unfortunately, it is not possible to predict with certainty which AVMs will remain stable throughout someone’s lifetime, and which are in danger of rupture.

Where are AVMs located? About 90% of the AVMs reported on this website are located in the brain. The other 10% are located in the face, neck, chest, arms, legs, hands, feet, internally, or anywhere in the circulatory system. If you have lung AVMs (pulmonary AVMs, or pAVMs), gastro-intestinal AVMs, or AVMs in other internal organs, you should be evaluated for HHT, preferably at an HHT Center of Excellence. If you have more than one AVM, you should be evaluated for HHT, Cowden Syndrome, or other conditions that may cause multiple AVMs. The vast majority of members on this community, however, report only one AVM.

How are brain AVMs treated? Brain AVMs may be treated by open brain surgery to remove the AVM (craniotomy), by radiosurgery (Gamma knife or Cyber Knife, for example), by embolization (a trans-catheter procedure blocking the flow of the AVM with “glue” or “Onyx”), or by a combination of treatments (for example, embolization followed by craniotomy or radiosurgery). There is also “watchful waiting,” which means that your doctor may advise no treatment at present, but will monitor and possibly offer medical management for symptoms.

AVMs are as unique as people, so what is best for one person is not necessarily best for another. Getting several opinions from doctors (typically neurosurgeons) who have extensive experience with AVMs and whose hospitals are in a position to offer any of these alternatives is essential to determine which option is the most appropriate for your AVM.

How are AVMs in other parts of the body treated? Small, focal AVMs outside the brain may be treated with surgery (resection). However, AVMs outside the brain may be large or diffuse, in which case other treatment options may be preferable, or a combination of surgery and other treatments. Embolization to “shut down” parts of the AVM or sclerotherapy to kill off some of the AVM vessels may be appropriate. Getting several opinions from doctors with extensive experience treating your type of AVM is recommended.

Patients with extensive malformations, such as those with Parkes-Weber Syndrome or Klippel-Trenaunay Syndrome, should be particularly careful to get several opinions before deciding on treatment, as complications such as venous insufficiency may result from treatment. For AVMs in the limbs, compression garments may be helpful. If the patient with an AVM in the limb is prone to blood clots (DVTs), NSAIDs may be recommended, though they may be contraindicated for other types of AVMs. For many people with AVMs outside the brain, treatment is often a long-term management situation rather than a single procedure. As with brain AVMs, sometimes watchful waiting is an appropriate option.

Do AVMs recur after treatment? AVMs can recur after treatment, so follow-up monitoring is important, particularly if new symptoms arise. The risk of recurrence rises if you are: young; female; your avm has deep venous drainage; you become pregnant, take hormonal contraceptives, or have an injury in the area of the avm; or if your avm is either a dural avm or an avm outside the brain. The majority of members on this community have not experienced recurrence. Do not spend your days and nights worrying about recurrence, but be aware that it can happen, and communicate any unexplained changes in your symptoms or your general health to your AVM doctor.


A post was split to a new topic: Surgery Recovery Time?

If the AVM was creating before birth. Will the AVM damage start after birth, if so is damage starting then or will the damage be ongoing waiting for a burst.

Mary, hi.

My understanding is that the gravest damage that an AVM does is if it ruptures. We know that they can have an impact on surrounding tissues in a number of ways, if the AVM puts pressure on brain, on the spinal cord and so on but the biggest impact is if it ruptures.

I guess that whether or how long it takes before a rupture occurs varies completely dependent upon the nature of each AVM: I am sure that they are all unique: and some will make their presence known aged seven and some aged seventy.

That spread of ages could be to do with the variation in each person’s AVM or it could be that some of us who are older have an AVM that has been acquired. I am sure we have some members here with dural arteriovenous fistulas where that would appear to be acquired, e.g. from a CVST stroke, rather than aboriginal, congenital.

So I think each one is unique: the only way to understand your risk is for a doctor to examine you; the only way to understand my risk is for the doc to examine me.

Does that help?