Brain Aneurysm
What is an Aneurysm?
An aneurysm is a blood-filled dilation of a blood vessel caused by a weakening of the vessel’s wall. Aneurysms typically develop because of the general wear and tear of blood pressure on the arteries’ walls, called hemodynamic forces. A weak spot in the artery wall bulges out, giving way to the pressure of the blood flow, forming a sac. For this reason, areas of artery or vessel wall which are submitted to higher blood pressures are more susceptible to aneurysm development, such as the branching points of arteries, called bifurcations. In the same way that a balloon stretches, the aneurysm sac balloons out from the vessel wall usually slowly, progressively becoming weaker.
What are the Risks of a Brain Aneurysm?
Approximately 2 million Americans have silent Unruptured Intracranial Aneurysms (UIAs). Most of these people do not know they have an Aneurysm and have no symptoms (estimates vary between 1.5-6% of the U.S. population). The most serious risk of a Brain Aneurysm is that it may Rupture, especially as it Grows or becomes enlarged (although Aneurysms may also Rupture at a smaller size, depending on their location, a Person’s Age, or associated Risk Factors. When an aneurysm ruptures, it results in bleeding with the head called hemorrhaging. This is a Type of Stroke termed “Hemorrhagic Stroke”. If a Person’s Brain Aneurysm Ruptures, approximately 15-30% will Die suddenly before they reach the hospital. Depending on the severity of bleeding and brain damage from the initial bleeding, about 50% of Patients will Die or suffer serious Disability, while the remaining survivors may experience Significant Recovery and return to a normal Independent Life. Although the most life-threatening risk is that of an Aneurysm rupturing, some People may develop symptoms from their Aneurysm compressing or “pushing” on important Brain structures. This can result in symptoms such as double vision, paralysis, sensory abnormalities, or seizures.
What are the Risk Factors for Developing a Brain Aneurysm?
- Traumatic injury such as a blow to the head (less than 1% of all cases)
- An infection (termed a mycotic aneurysm, (2% of all known cases)
- A hereditary predisposition (They can run in families; this accounts for 20% of all aneurysms)
- Cigarette smoking and hypertension or high blood pressure
- Use of drugs such as cocaine and amphetamines
- Certain blood vessel disorders: Fibromuscular Dysplasia, Marfan’s Syndrome, Ehler’s-Danlos, Polycystic Kidney Disease, Autoimmuni Cerebral arteritis, Dissections or “tears” in the Arteries
- No Known Risk Factors or the Degenerative Effects of Aging
What Increases the Risk of an Aneurysm Rupturing?
- Medical family history of Aneurysms or Prior Rupture
- Hypertension (high blood pressure)
- Tobacco use
- Female (3:2 female to male ratio for aneurysmal rupture)
- Younger age at Presentation, i.e. Between the ages of 35 and 60 have a greater Lifetime Risk of Rupture
- Certain locations are at higher risk, even at smaller sizes (Anterior Communicating, Posterior Circulation, etc.)
How Can a Brain Aneurysm be Treated?
- Risk Factor Reduction and Close Monitoring with Imaging
- Depending on your Age, Risk Factors, Location, and Size of the Aneurysm, many people may be at Lower Risk for Developing Symptoms or having their Aneurysm Rupture. We may advise that risk factors such as Blood Pressure and Smoking Cessation be managed with Serial Imaging be performed to monitor your Brain Aneurysm. If the Aneurysm shows signs of Growth or has a change in it’s Morphology (shape changes or an irregularity develops), further Treatment options may be considered.
- Neurointerventional or Neuroendovascular Therapy
- If a Person is Young, or has certain Risk Factors such as Larger Size, Irregular Shape, or High Risk Medical Conditions, Minimally Invasive Treatment of their Aneurysm may be considered.
- Neurointerventional Therapy is performed by accessing the Blood Vessels through a small incision in the Leg (Femoral Artery) or Arm (Radial or Axillary Artery) and Navigating small “Tubes” or Catheters into the Brain. Several Different Treatment Strategies may be employed to treat a Brain Aneurysm including placement of “Coils” within the Aneurysm to “Patch” it. Sometimes, special adjunctive devices such as a Balloon, Stent, Flow-Divertor, or Flow Disruptor may also be utilized to effect a more durable result and lower the risks of future Growth or Rupture of your Aneurysm. The Recovery Period for these Techniques is usually very short, as little as 1-2 days in the Hospital.
- Microsurgical Therapy
- In some Patients, the Aneurysm may not be well-suited to Minimally Invasive Treatments, and Open-Brain Surgical Therapy or a Craniotomy is performed and “Clipping” may be considered, especially if an aneurysm has ruptured. As Neurointerventional techniques have continued to evolve, this approach is less commonly needed, however, in certain situations, it remains a reasonable and safe alternative.
- Risks of Treatment
- Monitoring
- There is the possibility that an Aneurysm may Rupture or Grow during a surveillance period before there is an opportunity to treat with Neurointerventional or Microsurgical techniques. This may result in severe Brain Injury or Death associated with the Brain Hemorrhage as described above.
- Neurointerventional Therapy
- When a Person undergoes treatment of their aneurysm, there are risks that the aneurysm may rupture or that an important blood vessel may become blocked during the Operation. This could result in Severe Permanent Brain Injury or Stroke, Long-Term Permanent Disability, or even Death. These risks may vary based on the complexity of the Brain Aneurysm, but are usually less than with Open Microsurgical Treatment of most Aneurysms.
- Microsurgical or Open Brain Surgery Treatment
- As with Neurointerventional Therapy, the aneurysm may rupture or an important blood vessel may be occluded during the Operation which can result in Permanent Disability or Death. Open Brain Surgery also carries the additional risks of direct manipulation of the Brain and associated Brain Injury and is generally associated with longer recovery times and side-effects, including a risk of developing seizures.
- Monitoring
Special Thanks to Dina Chon (Executive Director) and The Aneurysm and AVM Foundation (TAAF) for their permission to use their illustrations and educational materials to help spread Awareness for these Life-Threatening conditions. Please visit their Site to learn more and Support this vibrant community.