This document summarizes information about unruptured brain aneurysms. It defines a brain aneurysm as a weak bulging spot on the wall of a brain artery. Most brain aneurysms cause no symptoms but some can press on brain areas and cause headaches or vision changes. A ruptured aneurysm causes a sudden, severe headache. Risk factors for aneurysm formation and growth include smoking, hypertension, age, and family history. Left untreated, aneurysms risk growth and potential rupture. The risk of rupture increases with aneurysm size. Treatment options are conservative management, surgical clipping, or endovascular coiling. The ISUIA study found coiling had lower morbidity, mortality, and dependency rates than clipping for unruptured aneurys

1. Unruptured brain aneurysm
(Incidentally detected brain aneurysms)
Dr. Avinash KM
MS, MRCS Ed(UK), Mch (KEM, Mumbai), FINR(Switzerland), FMINS(Germany),
• Interventional & Neurovascular surgeon and Stroke specialist,
• Endoscopic Neuro and Spine surgeon,
• Minimally invasive Neuro and Spine surgeon (FMINS).
mob: 9740866228, E mail: doc_avin@hotmail.com
Consultant Neurosurgeon and Neurointerventionist
Columbia Asia Hospital, Bangalore.

2. What is brain Aneurysm?
A brain aneurysm, also referred to as a cerebral aneurysm or intracranial
aneurysm (IA), is a weak bulging spot on the wall of a brain artery very much
like a thin balloon or weak spot on an inner tube. Over time, the blood flow
within the artery pounds against the thinned portion of the wall and
aneurysms form silently from wear and tear on the arteries. As the artery wall
becomes gradually thinner from the dilation, the blood flow causes the
weakened wall to swell outward. This pressure may cause the aneurysm to
rupture and allow blood to escape into the space around the brain. A
ruptured brain aneurysm commonly requires advanced surgical treatment

3. What are the symptoms of aneurysms?
1. Asymptomatic incidentally detected aneurysms
2. Symptomatic unruptured aneurysms
3. Ruptured aneurysms
Most brain aneurysms cause no symptoms and may only be discovered during tests for
another, usually unrelated, condition(Asymptomatic incidentally detected
aneurysms).
In other cases, an unruptured aneurysm will cause problems by pressing on areas in
the brain. When this happens, the person may suffer from severe headaches, blurred
vision, changes in speech, and neck pain, depending on what areas of the brain are
affected and how bad the aneurysm is.
Symptoms of a ruptured brain aneurysm often come on suddenly. A sudden, severe
headache that is different from past headaches.(worst headache of life)
Neck pain.
Nausea and vomiting.
Sensitivity to light.
Fainting or loss of consciousness.
Seizures.

4. What are the risk factors for formation of aneurysm?
Modifiable risk factors Non modifiable risk
factors
Smoking
Hypertension
Heavy drinking
OCP
Atherosclerosis
Coffee use
Age
Female sex
Genetics/familial
Collagen vascular diseases
AVMs

5. What happens if aneurysm is not treated?
Risks if not treated: (read next slides)
• Growth of aneurysms
• Risk of bleeding
Aneurysm rupture is a devastating event. Approximately 15-20
percent of patients die prior to reaching the hospital and, of
those who make it in time, only one-third will have a "good
result" after treatment. Therefore, salvage treatment is not
effective.
Risk factors for rupture:
• Size of the aneurysm
• Posterior circulation location
• Symptomatic aneurysm
• Previous history of bleeding
• Increase in size
• presence of a daughter sac in the aneurysm,
• family history of SAH and
• patients with autosomal dominant polycystic kidney disease (ADPKD)

6. What is the growth rate of incidentally detected
aneurysm?
2 to 4 mm sized incidentally detected
aneurysm
Growth is about 2.4% per year.(24
people out of 1000 who have incidentally
detected aneurysm will grow in a year)
5 to 9mm Aneurysms 9.1% per year aneurysms will grow
10 to 20mm Aneurysms 50% per year
It is clear from the chart that as the size of the aneurysm increases, the chance
of their growth also increases

7. What is the risk of bleeding of unruptured /incidentally
detected aneurysms?
Size of aneurysm Asymptomatic aneurysms With previous symptoms
Less than 10mm 0.05% / year 0.5% / year
10 to 25 mm 1% / Year 1% / year
More than 25 mm 6% / year 6% / Year
Risk of bleeding: ISUIA study:
Size Anterior circulation
aneurysms
Posterior circulation
aneurysms
Less than 7mm 0.1% 2.5%
8 to 12 mm 2.6% 14.6%
13 to 24 mm 14.5% 18.4%
Morethan 25mm 40% 60%
ISUIA 2 study: risk of bleeding -five years cumulative risk of bleeding

8. It is clear from the previous slides that both
growth of aneurysm and their risk of bleeding
increases as the size of the aneurysm
increases.
Therefore large aneurysms and growing
aneurysms detected incidentally should be
treated

9. Treatment options:
1. No treatment(conservative management)
2. Surgical clipping
3. Endovascular coiling

10. No treatment: conservative management
• Control of hypertension
• Cessation of smoking
• Periodic follow-up imaging( yearly)
• Treatment if the aneurysm is growing or
patient complains of headache or if any
cranial nerve paresis.

11. Surgical clipping
Clipping:
Watch following videos for better
understanding of clipping
http://www.youtube.com/watch?v=PaTzNaTOoxI
http://www.youtube.com/watch?v=hJACYm7PPg0

12. Endovascular coiling:
Read brain aneurysm coiling presentation to
understand about different techniques of coiling
• Coiling: http://www.youtube.com/watch?NR=1&feature=endscreen&v=5Ss-IOmFyeA
• Flow diverter: http://www.youtube.com/watch?v=jd5VQTS096E&feature=related
• Stent assisted coiling: http://www.youtube.com/watch?v
=MfdPbBZ6ETs&feature=related

13. Which treatment is better? Coiling or clipping?
Morbidity and mortality:
ISUIA study(International Study on Unruptured Intracranial
Aneurysms): this is one of the largest study done on
unruptured intracranial aneurysms to date.
The study showed that
Death and dependency at 1 year:
Surgical clipping:
• The 30-day overall morbidity and mortality rate with surgery was
13.2%, and the mortality rate was 1.5%.
• The 1-year morbidity and mortality rate was 12.2%, and the mortality rate
was 2.3%.
Endovascular treatment:
• In the endovascular group, the 1-year total morbidity and mortality rates
were 9.5% and 3.1%, respectively.

14. Personal comment
• It is my personal belief that small aneurysms can also rupture
and it is better to secure them if technically feasible irrespective
of what trials and numbers show simply because Aneurysm
rupture is a devastating event. Approximately 15-20 percent of
patients die prior to reaching the hospital and, of those who
make it in time, only one-third will have a "good result" after
treatment. Therefore, salvage treatment is not effective.
• One has to take into consideration the psychological factor. No
matter what the statistics show, no one can guarantee a risk-
free choice. After explaining the pros and cons, we have to take
care of the patient’s psychology and help them make decision.
If the patient cannot accept the psychological burden of having
a 'time bomb' in his /her head, treating a small aneurysm may
be justified.

15. The above clinical trial which is the largest trial to
date clearly shows the benefit of endovascular
coiling in unruptured aneurysms. Technically
feasible should under go coiling.