Arteriovenous Malformation (AVM)
What is it?
In the normal state, the arteries pass through, dividing into increasingly smaller branches. Upon reaching their destination, they are further divided into a large number of capillaries, vessels with very small diameter, thus leading to a significant decrease in pressure.
An arteriovenous malformation is an interlacing of arteries and veins connected to each other without the usual intermediate capillaries. The blood circulating in the abnormal vessels of the malformation moves rapidly and reaches the veins at a very high pressure not reduced by the capillaries. The veins dilate and their walls, unable to withstand this pressure, can rupture, leading to a cerebral hemorrhage.
Causes and risk factors
They are congenital malformations, without any identifiable cause. They are not hereditary, and relatives are not at greater risk than the rest of the population.
Which are the symptoms?
They can lead to various problems. The two most common are:
- vein rupture followed by cerebral hemorrhage;
- irritation of the adjacent brain tissue with the appearance of epileptic seizures.
How is it treated?
They can be treated by a variety of methods, including a combination of them:
- Stereotactic Radiosurgery (Gamma Knife). It plays an important role in the treatment of patients suffering from this disease, and consists of an extremely precise concentration of gamma rays on the malformation, resulting in the gradual closure of vessels replaced by scar tissue over a period of six months to three years. This procedure is best suited for small size malformations with weak flow.
- Surgical intervention. The entire perimeter of the arteriovenous malformation is isolated with closure of the arterial blood flow, and the entire malformation is removed after vein closure.
- Endovascular method. It is used to close the malformation. It is performed using a technique similar to diagnostic angiography: different materials (glue, particles, etc.) are introduced into the arteriovenous malformation using a thin catheter, which stops the blood flow in the pathological vessels. Endovascular embolization is usually used before surgery to reduce the size of the malformation. This method can also be used before radiosurgical treatment to make the malformation smaller and thus provide a better result.
Because this is a complex pathology, the choice of treatment should be discussed in specialized centers, where the advantages and disadvantages of surgery, endovascular treatment and stereotactic radiosurgery can be evaluated.
For optimal identification of the lesion to be treated, each patient undergoes stereotactic magnetic resonance imaging and cerebral angiography, on the basis of which a treatment plan is drawn up.
The effectiveness and possible complications depend on the size and location of the malformation. Statistical studies are now available to select the therapeutic dose for each AVM that provides the best risk-benefit ratio.
Where do we treat it?
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