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Brain aneurysm and arteriovenous malformation (AVM)

  • Allina Health offers exceptional care for patients with brain aneurysms and arteriovenous malformations (AVMs). We take a multidisciplinary approach to care, which means world-class neurovascular specialists collaborate with experts in complementary fields, resulting in the best individualized care for each patient. The physician team includes vascular neurosurgeons, interventional neuroradiologists, vascular neurologists and neurointensivists.

    What is a brain aneurysm?

    An aneurysm forms when an artery in the brain develops a bulge. This is caused by a weak area in the blood vessel's wall. The aneurysm can break open and bleed. This is a medical emergency and requires treatment right away. 

    Aneurysms that bleed are very serious: half of patients die before reaching a hospital or within the first few days. Of the patients who survive a ruptured aneurysm, half develop a serious disability. A ruptured brain aneurysm requires treatment because it is likely to bleed again. Each time a brain aneurysm bleeds, the risk of death or disability is high.

    Location of aneurysms in the brain

    Many aneurysms occur in the large arteries at the base of the brain. Arteries carry blood pumped by the heart and the blood flows at high pressure. When a brain aneurysm breaks open (ruptures), blood escapes into space around the brain called the subarachnoid space. The bleeding is called a subarachnoid hemorrhage. 

    Unruptured aneurysms

    Sometimes aneurysms that haven't ruptured and have no symptoms are discovered by chance. The neurosurgeon and/or interventional neuroradiologist team will consider an unruptured aneurysm very carefully. The risks of preventive treatment will be weighed against the aneurysm's likelihood of bleeding. Sometimes, for a patient with an unruptured aneurysm, observation alone may be appropriate.

    What is an arteriovenous malformations (AVM)?

    Vascular malformations are abnormal connections between the arteries and veins in the brain. They are also called arteriovenous malformations (AVMs). These usually form before birth.

    AVMs are located within the brain. Without the normal channels of vessels to handle blood under high pressure, AVMs can bleed. The bleeding causes a blood clot in the brain, which can lead to death or disability. Although not as dangerous or common as brain aneurysms, AVMs have significant risks.