Arteriovenous Malformations
and Fistulas

Overview

In an arteriovenous malformation (AVM), blood passes quickly from the artery to vein, disrupting the normal blood flow and depriving the surrounding tissues of oxygen. 

An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels connecting arteries and veins, which disrupts normal blood flow and oxygen circulation. With this alteration in normal blood flow, the affected arteries and veins can weaken and rupture leading to bleeding in the brain, stroke and brain damage. Arteriovenous malformations most often develop in the brain or spine. As with brain aneurysms, they are often found incidentally during workups, and once diagnosed, treatment can be performed to prevent the risk of future bleeding or other complications.

Treatment of an AVM depends on many factors such as whether or not the AVM has bled, whether there are symptoms, and where the AVM is located. The primary treatment for AVMs is surgical, either through open surgery, endovascular embolization or a combination of both. With endovascular embolization, a small catheter is threaded through the vessels to the AVM. A glue like substance is then injected to slow down or block flow to the AVM. Often this is done as a first step prior to open surgery to decrease the bleeding risks of open surgery, although in select cases, embolization alone can be curative.

Not all AVMs need to be treated, as some may be carefully followed through routine imaging. Whether or not to treat an AVM is a discussion that Dr. Geraghty will have with you weighing the risks and potential benefits. If treatment is the best option, Dr. Geraghty works closely with his Neurosurgery partners in determining the best treatment options whether that be endovascular embolization, open surgery or a combination of both.

What to Expect

In most cases, Dr. Geraghty will first perform a diagnostic angiogram in order to help grade the AVM or AVF as well as for planning purposes if endovascular treatment is decided upon. If this is the case, a separate embolization procedure will be planned. AVM and AVF embolization is performed under general anesthesia and typically lasts 2-3 hours. Following the procedure patients are admitted to the Neuro ICU for close monitoring.

If the embolization is performed as part of a combined surgical approach to cure, then patients can expect to remain in the ICU until the open surgical procedure which typically will happen within a day or two of the embolization. Due to their intrinsic complexity, some AVMs and AVFs will be treated in a staged fashion where patients can expect 2 or 3 embolization procedures spread out over several weeks or months depending on individual circumstances.