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Arteriovenous malformation (AVM)



Arteriovenous Malformations (AVM) is a disease caused by the merging of the cerebral arteries and veins, also known as vascular clumps, in the form of clumps without capillaries between them. There is no brain tissue in the nucleus. AVMs are congenital pathologies, tending to grow with age, changing from low flow to medium-high flow and high pressure lesions.


It is seen at an average rate of 0.14% and slightly more in men. Since they are congenital, there is a lifelong risk of bleeding. 64% of AVMs are diagnosed before the age of 40.


How it appeared:

  • Most often with bleeding

  • With seizures (Fainting-epilepsy seizures)

  • With the symptoms of pressure formations due to mass effect

  • Since the blood flow is high in AVMs, it reduces the blood supply of the surrounding brain tissues (stealing effect) and causes symptoms that occur due to this.

  • Rarely with headache

  • With signs of increased intracranial pressure


The most common age for bleeding is 15-20 years. 10% of them result in death. For each hemorrhage, there is a 30-50% risk of neurological impairment. Small AVMs bleed more often than large AVMs. The average bleeding risk of AVMs is 2-4%/year.

20-year risk: 10-19 years → 44% risk; 20-29 years → 31%; 30-60 years → 6%. There is a risk of seizure within 20 years in 22% of patients presenting with bleeding.


Aneurysm may also be present in 7% of patients with AVM and is often on the feeding artery.



Diagnosis is made by computed tomography, MRI and angiography. Angiography should be performed especially to see the feeding and draining vessels.


Each option has its own advantages and disadvantages. Many factors are taken into account when deciding on treatment.


Surgical treatment:It is the first choice for shopping malls. If the surgical risk is unacceptable, alternative interventions can be considered. It is advantageous because it eliminates the risk of bleeding immediately, because it has better seizure control.


Radiation therapy:Today, stereotactic radiosurgery (Gamma knife, cyber knife, etc.) is performed. It is effective in small (≤2.5-3 cm core) deep AVMs with a high risk of complications during surgery. Since its effectiveness occurs within 1-3 years, there is always a risk of bleeding in this period.


Endovascular techniques:(embolization) It is the filling of the vascular ball with a substance by angiography. It can also be done before surgery. It reduces the risk of bleeding during surgery. It is not sufficient for permanent occlusion alone, it may cause acute hemodynamic changes, more than one intervention may be needed.

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