ARTERIOVENOUS MALFORMATIONS

Arteriovenous malformations are abnormal tangles of blood vessels inside the brain or spinal cord. 

The usual pathway for blood flow is to pass from a high pressure system- the arteries into the capillaries which is where they supply the tissue and then the blood flows back into the low pressure system-i.e the veins. 

The capillaries that normally exchange blood between the arteries and the veins develop abnormally in an arteriovenous malformation. As a result, the arteries dump blood directly into the veins. 

Over time, there is transmission of high blood pressure of arterial blood flow into the venous system which is normally accustomed to low pressures. 

The veins then dilate and become engorged, creating the risk of rupture and hemorrhage, as well as seizures, headaches and other symptoms.  

Arteriovenous malformations can compromise blood flow to the surrounding tissue both by compression and by "stealing" blood from normal vessels, due to their high flow state. They can eventually result in bleeding which can be disabling or life threatening.

While many arteriovenous malformations remain asymptomatic for life, they can cause serious problems when they occur inside the brain as a cerebral arteriovenous malformation, or in the membrane covering the brain  (the dura) , or in the spinal cord as a spinal arteriovenous malformation.

Arteriovenous malformations present with headaches, seizures and other symptoms.

These symptoms typically develop between the second and fourth decade of life. 

 Half of all brain Arteriovenous malformations present with a brain hemorrhage, while the rest typically present as a seizure , a headache, or a neurological deficit like weakness, numbness, balance problems or vision problems. The symptoms usually occur between second and fourth decades of life. Studies indicate that untreated Arteriovenous malformations carry a high long-term risk of hemorrhage, stroke or death.

An Arteriovenous malformation that has recently hemorrhaged is at a greater risk of another bleed. The re-bleed rate over the first year following a hemorrhage is close to 10%. 

In the patients who bled from arteriovenous malformation, treatments are usually emergent or semi emergent.  In patients who did not bleed, the treatments can be planned. 

 The primary goal in the care of any Arteriovenous malformation patient is long-term elimination or reduction in the risk of brain hemorrhage (stroke). 

Every patient and every Arteriovenous malformation in the brain and the spinal cord is different.  and the specific short -term and long-term benefits of all the treatment modalities and risks are discussed in detail.