AVMArterio Venous MalformationsThis web page is hosted by Melanie Torres (melanietorres@carolina.rr.com). My son has an AVM and we are building a support group. Please send me a note and watch this space for new developments. (We will be adding a chat forum and some other ways to communicate. Contents:
What are AVMs?An Arterio-Venous Malformation, or AVM is an abnormal collection of blood vessels. Normally, red oxygenated blood is pumped by the heart through branching tubes called arteries to the brain where it enters a fine network of tiny vessels called capillaries. It is in these capillary beds where the blood nourishes the tissues. Blue, deoxygenated blood then passes back to the heart back through branching thin walled tubes called veins. Arterial-Venous-Malformations are areas that lack the tiny Capillaries. The location of the connection between the artery and the vein is called the shunt. The area of tissue is called a nidus of the AVM. An AVM can be thought of as a "Short Circuit" where the blood does not go to the tissues but is pumped through the shunt and back to the heart without ever giving nutrients to the tissues.
What causes AVMs?We don't know what causes most AVMs. People are born with AVMs, although they do not appear to inherit them from their parents nor do they give them to their children. It appears that AVMs may be caused by a rupture or clotting of a blood vessel that happens during development before one is born. It is usually not associated with either other maldevelopments or with other AVMs.
What are the dangers of AVMs?Usually, patients do not know they have an AVM. A number of the patients with AVMs have seizures or persistent headaches. An AVM can put additional strain on the blood vessels and the surrounding tissues. This is usually well tolerated in the first 2 decades of life. But the increased flow of blood caused by the shunt weakens the blood vessels. These weakened blood vessels can rupture. This is known as a hemorrhage or bleed. If an AVM bleeds, the patient almost always has an extremely severe headache, and most commonly has a stroke and often dies. The chances of an AVM bleeding is 4 % per year. Larger AVMs occasionally may cause progressive neurological problems by putting pressure on the brain or altering the blood flow.Is there any activity I should avoid?Do not use aspirin or aspirin containing compounds. Do not use non-steroidal anti-inflammatory agents. If you were to bleed, these agents may make the bleed worse. There is no other activity that is known to protect or cause a bleed in this condition.
How is the diagnosis made?AVMs can be seen on outpatient imaging studies such as CT's or MRI's. Angiograms are inpatient procedures needed to image the arteries and veins before any treatment. An angiogram is a x-ray movie of the blood flowing through the blood vessels. It is made by injecting contrast into the arteries going into the head and taking a series of x-rays films.
What are the treatments for AVMs?Treatment for AVMs include, Surgery, Radiation, Embolization or a combination of these methods. With all of these treatments. complete obliteration of the AVM is needed to avoid bleeding. Parietal treatment of the AVM is not known to offer any benefit except for very specific conditions. Each treatment has it advantages and disadvantages that make tailoring the type treatment to the particular AVM the most sense.
Treatment Options and their Advantages/Disadvantages?
What is Embolization Therapy?Embolization is a method of plugging the blood vessels of the AVM. Under X-ray guidance, a small tube, a catheter is guided from the femoral artery in the leg up into the area to be treated.A neurological exam is performed before and after a small amount of medicine is injected. This can help tell if the vessel that feeds the AVM also feeds normal and important portions of the brain. After this, a permanent agent is injected into the AVM and the catheter removed. This is repeated for each vessel that feed the AVM. During the embolization, the patient is awake but is made comfortable with the help of the anesthesia team that monitors them and gives them medicines by an intravenous line. After the embolization the patients usually spend the night in the Neurological Intensive Care Unit (NICU) where they can be monitored closely. Patients are usually hospitalized for 3 nights for each embolization and usually require 2-3 embolizations at 2-6 week intervals. Patients resume their normal full activity immediately upon each discharge. There may be some mild headache after the embolization related to the blood vessels of the AVM clotting, or some nausea related to some of the medicines that are given.
What are "investigational studies"?AVMs are a rare condition affecting about 250,000 people in the United States. Much remains to be known. Which AVMs bleed ? Why do they bleed when they do? What type of AVMs are there? Which is the best way to treat each type of AVM? How can one maximize the benefits and minimize the risks of treatments. These questions can only be answered by studies.Any study requires the consent of the patient, approval of the hospital and often the approval by the FDA and the company involved in making a medicine or material. The nature of the study and the reason for the study is explained in a consent form. You may be asked to participate in such study. If you are, it will be explained to you and you will be asked to sign a special consent.
|
|
