Treating Arteriovenous Malformation (AVM) Of The Brain

Characterized by headaches and seizures, an arteriovenous malformation (AVM) of the brain is a derivative of arteriovenous malformation, a disorder of the body’s circulatory system. An AVM of the brain, also known as a cerebral AVM, is a malformed group of blood vessels composed of an intricate tangle of arteries and veins. Though localized, cerebral AVMs can lead to severe neurological problems. Research in the field of arteriovenous malformation is growing particularly with noninvasive treatment options.

nWhat are cerebral AVMs?

nCerebral AVMs may form during prenatal stages of a child’s development, either during embryonic or fetal growth. Studies have found a certain number of cases form shortly after birth; however, the condition frequently presents in adults in their 20s or 30s. Cerebral AVMs are commonly misdiagnosed, with most cases found only incidentally through the performance of CT (computed tomography) scans on the brain. Patients complain of regular headaches and seizures before diagnosis.

nOther neurological complications can develop including speech and visual difficulty, dizziness, memory deficits, confusion, hallucinations, dementia and difficulty with event planning. Physical side effects range from loss of coordination, numbness, tingling and spontaneous pain to permanent paralysis. Patients’ symptoms are directly associated with the location of the cerebral AVM with certain sites causing hydrocephalus. Hydrocephalus is caused by a cerebral AVM preventing the circulation of cerebrospinal fluid thereby causing fluid build-up in the skull.

nWhat are the potential health consequences of cerebral AVMs?

nHemorrhaging is the most common side effect of patients experiencing cerebral AVM. The size and location of the cerebral AVM determines the patient’s likelihood of experiencing hemorrhaging. Research has found between 2 and 4 percent of all AVMs to hemorrhage each year with most episodes going undetected. Minor hemorrhaging does not cause neurological damage, hence the reason patients and doctors remain unaware it takes place. On the other hand, massive hemorrhaging has been documented with some cases being fatal. Once a cerebral AVM bleeds, the risk of hemmorahaging again within the next year is nine times as likely. Though research has grown extensively, doctors are still unable to predict whether a patient with cerebral AVM will or will not experience hemorrhaging.

nWhile there is no definitive research, doctors have found certain cases to have a higher likelihood of causing bleeding. Though it may seem contradictory, smaller AVMs have a greater chance of hemorrhaging than larger ones. Increased blood pressure and blood volume from being pregnant also increases a patient’s potential for bleeding. Lastly, deeply situated AVMs with extremely narrow veins impair proper drainage leading to an increased risk for hemorrhaging.

nOnce again, the location of the hemorrhaging AVM is directly proportionate to the side effects of hemorrhaging. Bleeding AVMs situated deep within the brain, called intracerebral or parenchymal cerebral hemorrhage, cause the most damage.

nIn addition to brain hemorrhaging, AVMs on their own can inflict harsh brain and spinal dysfunctions. Patients who experience severe side effects are typically victims of one of three problems. Aside from hemorrhaging, AVMs reduce oxygen reaching neurological tissues and compress and displace parts of the brain. The larger the lesion, the greater chance of the latter problem occurring with certain AVMs reaching up to 2.5 inches in diameter. Certain lesions have been documented to distort an entire hemisphere of the brain.

nHow is an AVM of the brain diagnosed?

nBrain AVMs can be diagnosed using a few methods, with the most non-invasive techniques being CT and MRI scans. Both scans reveal lesions while CT scans are particularly helpful in showing hemorrhaging. Three dimensional representations of cerebral AVMs can be detected by CT and MRI imaging.

nA more intricate process in identifying an AVM of the brain involves angiography. A contrast agent, or water-soluble dye, is injected into the brain allowing an x-ray to deliver more precise images that highlight blood vessel structure. This procedure carries the risk of causing a stroke, but more research has led to vast improvements with angiography thereby reducing stroke potential.

nWhat treatment options are available?

nEndovascular embolization is growing in popularity as a non-invasive treatment option for patients with cerebral AVMs. Dr. Alejandro Berenstein, the director of Beth Israel's Hyman-Newman Institute for Neurology and Neurosurgery (INN) at Roosevelt Hospital in New York City, is a pioneer in the field of endovascular embolization. Using research-driven methods, Dr. Berenstein performs embolization prior to surgery reducing the risk of complications.

nEndovascular embolization involves guiding a catheter through the arterial pathway into the site of the AVM. A substance is injected into the site reducing the blood flow through the lesion. Blood flow reduction is a proven method in making surgery a safer process for patients.

nConventional surgery follows endovascular embolization whereby the central portion of the AVM is completely removed causing minimal to no invasion of surrounding neurological structures. Deeply situated lesions typically are not considered for conventional surgery. However, experts in endovascular embolization such as Dr. Berenstein are finding significant success in reaching deeper AVMs, which can be followed by conventional surgery. In this case, the risk of mortality and complications are further reduced.

nRadiosurgery is another option for patients with localized lesions. Radiosurgery involves targeting the center of the lesion with a radiation beam damaging the blood vessel walls. Over several months following radiation treatment, the vessels begin to degenerate and ultimately close.

nThe method of surgery performed is thoroughly evaluated with each surgeon identifying the best option on a case-by-case basis. Left untreated, cerebral AVMs can cause severe hemorrhaging, which may lead to serious complications or death.

nWhat is the outlook/prognosis for patients after treatment?

nEmbolization and radiation therapy often lead to temporary results. When a cerebral AVM is large, radiosurgery takes months to heal leaving the patient still at risk for hemorrhaging.

nResearch in the field has found endovascular embolization coupled with either conventional surgery or radiation therapy to have the best results. The risk of complication or death is minimized with duel therapy treatments.

nDisclaimer: This article is for informational purposes and should not be considered a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any question you may have regarding a medical condition.

nAbout the Center for Endovascular Surgery

nThe Center for Endovascular Surgery is a division of Beth Israel's Hyman-Newman Institute for Neurology and Neurosurgery (INN). The Center for Endovascular Surgery is a world leader in using minimally invasive techniques to treat vascular disorders throughout the body, including brain AVMs, hemangiomas and cerebral hemorrhages. To learn more please visit: www.vascularcarenyc.com.