Unruptured aneurysms

When treatment is necessary, factors influencing risk, and management options.

I have an aneurysm. Does it need to be treated?

Not necessarily.

Aneurysms can be dangerous but some require no treatment at all. The decision to treat is often a complex one and requires discussion with an experienced medical professional. Any medical treatment involves a degree of risk, no matter how small. It is probable that for certain low-risk aneurysms the risk of the aneurysm is outweighed by the risk of the treatment.

For incidentally discovered unruptured brain aneurysms there are three broad management strategies:

1. Monitoring with scans: a period of observation may be undertaken to ensure the aneurysm is not growing or changing.
2. Endovascular treatment. This involves treating the aneurysm through the blood vessels. Generally, a small incision is made in the groin or wrist and a very thin tube is directed, under X-rays, into the aneurysm. Through this tube tiny coils and stents can be inserted to block off the aneurysm. This is less invasive and usually safer than surgical treatment.
3. Surgical clipping. This is an operation involving temporarily removing some of the skull bone (‘craniotomy’) to access the aneurysm and place a clip around its neck. It is by nature more invasive than endovascular treatment. The procedure is carried out with the use of an operating microscope.

There are no medications that can be given to shrink aneurysms, however stopping smoking and controlling blood pressure (if it is high) can reduce the risk of rupture.

What factors might lead to an aneurysm being treated?

• Symptoms: If the aneurysm is causing symptoms such as double vision or headaches. This is uncommon, however, as most aneurysms do not cause symptoms.
• Location: Aneurysms located in certain parts of the brain are more dangerous than others. This includes aneurysms within the ‘posterior’ circulation, which includes the basilar, vertebral, and posterior cerebral arteries.
• Size: Larger aneurysms are more likely to rupture. This rule does not hold universally true, however, as it is not uncommon to see ruptured smaller aneurysms. Conversely large aneurysms in certain locations (such as cavernous aneurysms) are not thought to be very risky.
• Shape: Aneurysms with an irregular shape have been associated with increased rupture rates.
• Previous aneurysm rupture: If the aneurysm has previously ruptured, or the patient has other brain aneurysms which have bled before, then treatment is more likely to be recommended.
• High blood pressure: Blood pressure should be controlled in patients with aneurysms as it predisposes aneurysms to rupture.
• Smoking: Aneurysms are more likely to rupture in people who smoke and cessation is recommended if possible.