An arteriovenous malformation (also known as AVM) is a "short circuit" between the arteries which carry blood from the heart at high pressure to all the tissues of the body.
The arteries provide oxygen and all the needed nutrients at the capillary level, and then the blood returns through the veins. Through the veins, the blood gets re-oxygenated in the lungs, cleaned at the kidneys, acquires nutrients at the liver, and then returns back to the heart. Commonly, the connection between arteries and veins is through a network of smaller vessels called capillaries, which slow the blood down and permit the exchange of food, oxygen, and nutrients into the tissues. When arteriovenous malformations occur, the arteries and veins have a direct connection, without the capillary network – they are malformed.
Arteriovenous malformations are called “high flow” malformations – contrary to venous malformations, that are more frequent but are called “low flow” malformations. The implications are important in the effect that arteriovenous malformations have on the circulation in general (and the heart, in particular) and mostly in the new born or very young, where they may produce various degrees of heart failure.
Types of Arteriovenous Malformation
Arteriovenous malformations may occur at any part of the body, but these are most frequently seen in the brain, followed by the head and neck. An arteriovenous malformation may present at any age, but it typically presents later in childhood or, more frequently, in adults in their 20s or 30s.
Simple arteriovenous malformations can have one arteriovenous fistula, or abnormal short circuit connection. In more complex malformations, this network of abnormal connections represents the "nidus.” The most severe expression of all arteriovenous malformations is the vein of Galen malformations.
Arteriovenous Malformation Symptoms
Arteriovenous malformations can present as soft tissue deformities. They frequently will produce skin discoloration (reddish or dark reddish hue) with elevated temperature to palpation and prominent pulsations (with a vibrating, electric feeling or thrill) representing the increased blood flow. They may present with severe bleeding. When in the skeleton, they can expand the bone and can cause the loss of teeth due to very severe bleeding.
Treatment Options for Arteriovenous Malformations
Arteriovenous malformations can be difficult to treat and often require a multidisciplinary approach to care. At Mount Sinai, our Cerebrovascular Center team takes a comprehensive approach to manage this condition. We balance the risk of bleeding and injury against the risk of any potential treatment in order to ensure each patient is informed of all options and is offered the very best care for his or her disease.
Embolization is the intentional, therapeutic occlusion of the abnormal circulation, fistula, or nidus. It is important that the normal arteries and veins are preserved. In general, a variety of agents are available to inject and close the abnormal malformation, and the exact type of embolic agent will vary depending on multiple factors, such as location, flow characteristics, size of the abnormal vessels, and malformation.
At Mount Sinai’s Cerebrovascular Center, the main agents used, are liquid agents, such as acrylics, such as medical “crazy glue”, or a slow hardening agent. For patients with cerebral AVMs that cannot be cured due to the size or location of their lesion, palliative embolization can improve the patient's quality of life and diminish symptoms such as headaches, seizures, or other problems.
Embolization for arteriovenous malformation is typically performed in preparation for surgical resection or radiation therapy. Commonly, combination treatments in a multidisciplinary medical center, such as Mount Sinai, are the best way to manage this complicated condition.
Klingenstein Clinical Center, 1-North
1450 Madison Avenue
New York, NY 10029