Arterio-Venous Malformations: a Definition and Discussion of Treatment Options Available

When I was in the first grade, my mom was routinely washing my hair. To her surprise, she saw a pulsating lesion inside my scalp. Although this was well before any of my cancer diagnoses it caused her alarm. We went to the physician who believed it was an arterio-venous malformation but decided surgery was needed to rule out aneurysm.

In January 1984, I had surgery to remove the lesion. Pathology came back with the result of it being an arterio-venous malformation. I asked in my six year old way what that meant and my dad said it meant a blob of tangled blood vessels. My brother teased me by saying the surgeon had to use a straw in my head to separate the vessels.

An arterio-venous malformation is a vascular lesion believed to arise during embryonic or fetal development. The lesion disrupts the process of arteries carrying blood away from the heart and veins carrying blood to the heart. With AV malformations, an artery is connected directly to a vein without intervening capillaries.

Considered congenital, AV malformations can be seen in families though no specific genetic or lifestyle factors are known. Sometimes AV malformations appear in the spectrum of a larger disorder. For me and later on my son, our arterio-venous malformations likely involve Cowden Syndrome (PTEN Syndrome). AV malformations can occur anywhere. My son’s AV malformation was in his abdomen while mine was in my scalp.

About 300,000 Americans a year are affected by AVMS with them being no respecter of race or sex. Usually AV malformations are silent and discovered incidentally to other problems. Approximately 12 percent of those affected have obvious problems and one percent dies each year.

There are sometimes signs of AV malformations including seizures, headaches on one side of the head, loss of coordination, visual field problems, dementia, and dizziness though the later signs are rare. In some cases those who have AV malformations of the brain experience a whooshing, rhythmic sound from the excessive blood flowing through the AVM. This sound is referred to as a bruit and is usually seen with those who have more severe cases.

The greatest danger of an AV malformation is hemorrhage. Because AVMs of the brain are more likely to affect additional systems, these pose a special danger. Smaller arterio-venous malformations are more likely to bleed especially if they have hemorrhaged within the year.

To determine if an arterio-venous malformation is present, several tests can be utilized. Angiography, a technique involving squirting dye into a vein in question is one option though it can present a risk of stroke. Computerized topography scans and magnetic resonance imaging are two less invasive techniques that can show AVMs.

Whenever possible AVMS are treated by surgery as was the case for both my son and me. Surgical treatment is not always an option due to placement of the AVM or size. For a period of several years after my AVM was removed, I underwent a regular MRI scan because sometimes AVMs can recur in spite of surgery. Radiation treatment is an option for smaller AVMs. Because radiation can cause the brain to swell, larger AVMs cannot be treated in this way. Embolization is a third option for treatment by injecting glue or an adhesive substance into the AVM to block it off.