What Affects Brain Aneurysm Survival Rates?

A brain aneurysm (cerebral aneurysm) is an abnormally bulging and weakened area of an artery in your brain. If it ruptures (bursts), it may cause a stroke and brain injury that’s fatal in about half of cases. About half of people survive a ruptured brain aneurysm, often with disability. 

Brain aneurysms occur in about 1-2% of people. Many people don’t know that they have them because they usually don’t cause symptoms unless they burst or are quite large.

Statistics for Ruptured Aneurysms

If not treated, 20-50% of brain aneurysms eventually rupture.

When an untreated brain aneurysm ruptures, it can cause a kind of stroke called a hemorrhagic stroke. This may lead to death before reaching the hospital in about 15% of cases. For others, the stroke can lead to disability or death within several months.

Statistics for Treated Aneurysms

Some people get preventive medical surgery to treat an aneurysm before it ruptures. This procedure has its own risks. The aneurysm can burst during the procedure, leading to brain injury. It can also cause blood clots, leading to problems such as heart attack.

Most people survive, but roughly 5% of the time, these attempted repairs lead to disability or death.

Many factors may influence your life expectancy if you have a brain aneurysm. Characteristics of an aneurysm that is more likely to rupture—making survival less likely—include:

• Larger size, or growing in size
• Irregular shape
• Certain locations, such as an artery toward the back of your head
• Previous leaking without rupture

Other factors in your medical history can also influence your risk, such as:

• High blood pressure, especially if it’s untreated
• Medical conditions that predispose you to aneurysms, like polycystic kidney disease
• Smoking
• Excess alcohol use or recreational drug use
• Family history of aneurysms
• Female sex

Factors Impacting Procedure Risks

Very large aneurysms are the most likely to cause complications during preventative repair.

The risk may also be higher the older you are. Having other medical conditions, such as diabetes, heart disease, and high blood pressure, can also increase your risk of complications.

There are a few options for treating or managing an unruptured cerebral aneurysm. The best approach may depend on your medical situation and personal preferences.

Open Surgery

Brain surgery is a standard approach to prevent an aneurysm from bursting. Usually this is a type of surgery called microsurgical clipping. The surgeon opens your skull and the area of your brain where the aneurysm is. Then they place a clip to block the blood flow to the aneurysm and to keep it from bursting in the future.

The risks can vary from person to person, though overall rates of complications from the surgery are about 4-10%. Most people survive: About 1-2% of people die from the surgery itself.

Potential complications may include:

• Aneurysm rupture or other causes of brain damage
• Heart attack 
• Seizures
• Infection
• Blood pooling beneath your skin (hematoma)

There’s also a small chance that the aneurysm won’t be completely fixed. Sometimes a repaired aneurysm later grows back. 

Less Invasive Medical Procedures

Less invasive options called endovascular procedures, which insert a coil or stent to block blood flow to an aneurysm, don’t open up your skull. Instead, doctors use a long, thin tube (called a catheter) threaded through a blood vessel in your arm, leg, or groin. They use imaging to guide tools through the catheter all the way to the aneurysm. 

In general, endovascular procedures may be a little less risky than brain surgery. However, many of the same complications can occur as in surgery, leading to disability or even death.

Endovascular procedures are also slightly less likely to work initially, and your aneurysm may be more likely to come back than if you had open surgery.

Conservative Approaches

In conservative management, your healthcare provider takes repeated imaging scans over time to make sure your aneurysm isn’t growing. But you don’t directly treat the aneurysm, which may carry it’s own risks.

It’s helpful to weigh the risks of surgery with the risk that your aneurysm will burst without treatment. Especially for older adults, the overall risks of procedures are often higher than the risks of aneurysm rupture.

Your healthcare provider can help you weigh the risks and benefits for your situation. 

If you’ve decided not to have a medical procedure, you can still take steps to minimize your risk of rupture. These include:

• Manage blood pressure: If you have high blood pressure, take steps to lower it. Work with a healthcare professional, who may prescribe medication.
• Avoid smoking: Avoiding smoking is also essential.
• Stay physically active: Moderate-intensity exercise like walking and swimming is important for your overall health, but your healthcare provider may recommend avoiding strenuous activities, like intense weightlifting, high-impact cardio exercises, or contact sports.
• Monitor your aneurysm: Keep regular follow-ups with your healthcare provider. Repeated imaging scans of your brain can show whether your aneurysm is growing, which can affect your treatment decisions.
• Get immediate medical attention: For signs of a leaking or burst aneurysm, like a sudden and severe headache or changes in your vision, get emergency care.

A ruptured brain aneurysm significantly increases the risk of long-term disability or death in about half of cases, but not everyone’s risk is the same. Surgeries or procedures to prevent aneurysm rupture also carry serious risks. If you have an untreated aneurysm, work with your doctor to get more details and to weigh the risks of a rupture or preventive treatment.