Arteriovenous malformation

Arteriovenous malformations (AVMs) are a structure of abnormal vessels, in which there is direct communication between the cerebral arteries that carry high flow and the low-flow cerebral veins. Under normal conditions arterial flow passes through blood capillaries and normal irrigation of the brain occurs, however, in the case of AVMs, this capillary bed does not exist, and therefore, the venous part of the malformation dilates due to the high blood pressure transmitted directly.

They can be congenital or acquired and their most serious form of presentation is the rupture. Other form of presentation are seizures or incidentally on imaging studies done for another reason. As usual, its location and size are essential to predict the risk of rupture and decide the appropriate treatment.

The existing strategies to treat these lesions are very variable, being sufficient the simple observation and periodic follow-up with imaging tests.

• Embolization

  It consists of introducing a catheter through the femoral artery and under radioscopic vision injecting different materials to close the passage from the arterial area to the venous area.



• Surgery

  Through a craniotomy, it is necessary to locate the arteries that feed the AVM and close them with clips, thus cutting off abnormal communication.



• Radiosurgery

  Despite the name, it is not a surgical procedure, but a specific type of radiotherapy, usually in a single dose, which is given in a very conformal and controlled way so that the nidus of abnormal arteries closes slowly, and eventually the abnormal flow is stoped. It is the least invasive of the procedures, but has a latency between the time of irradiation til the closure of the nest, which can last even several years.

In some cases of more complex AVMs, a combination of several of the treatments may occur.