Hydrogel Endovascular Aneurysm Treatment Trial

Your part in this study will last up to 24 months and will involve 6 visits (1 baseline visit
before your surgery, the surgical procedure and 4 follow-up visits). These visits will occur
at the same time as the visits you would receive as standard of care after your surgery.

If you are in this study, you will be placed in one of two study groups by chance using a
process similar to the flip of a coin. This process is called randomization. Neither you nor
the study staff will select the group you will be in. One group, the control group, will have
their aneurysm treated by the bare platinum coils during their endovascular procedure. The
other group, the study group will receive coils from the HydroCoil Embolization System. Both
groups will receive the same standard of care and follow-up, but during the surgery different
types of coils will be used.

Inclusion Criteria:

Candidates for this study must meet the following criteria to be enrolled in the study:

1. Patient is between 18 and 75 years of age (inclusive).

2. Patient has a documented untreated intracranial saccular aneurysm 3-14 mm diameter
angiographic lumen, ruptured or unruptured, suitable for embolization with coils.

3. Patients presenting with a HUNT and HESS Grade 0-3 or improving to such a grade before
treatment

4. Any type of bare platinum coils and HydroCoil ® Coils are treatment options (all
shapes allowed).

5. Patient or next of kin or person with appropriate power of attorney has provided
written informed consent.

6. Patient is willing and available for study follow-up visits

7. Patient has not been previously entered into this Study

Exclusion Criteria:

Candidates will be ineligible for enrollment in the study if any of the following
conditions apply:

1. Inability to obtain informed consent

2. Patient is < 18 or > 75 years old

3. Target aneurysm is not saccular in nature (mycotic, fusiform, dissecting).

4. Target aneurysm is > 14 mm maximum luminal dimension, < 3 mm maximum luminal dimension

5. Target aneurysm has been previously clipped or coiled

6. Target aneurysm is in the physician's estimate unlikely to be successfully treated by
endovascular techniques.

7. Patient has known hypersensitivity to platinum, nickel, stainless steel or
structurally related compounds found in HydroCoil®, HydroSoft®, HydroFrame® Coils
and/or bare platinum coils.

8. Baseline Hunt and Hess scale 4 or 5 for ruptured aneurysms

9. Intended use of a flow diverting stent (e.g. pipeline)

10. Subject has concurrent intracranial pathology, e.g.

- Moyamoya

- Vasculitis documented by biopsy results

- AVMs

- AV fistulas

- Significant atherosclerotic disease (i.e. symptomatic and or >50% narrowing of
the parent arteries necessary to traverse in order to coil the target aneurysm)

- Intracranial Hematoma (unrelated to the target aneurysm)

- Brain tumors

- Vascular tortuosity and other conditions preventing access to target aneurysm

11. Subject has serious co-morbidities that could confound the study results:

- Uncontrolled hypertension

- Uncorrectable coagulation abnormality

- Contraindications for heparin, aspirin or clopidogrel

- Uncontrolled Diabetes Mellitus

- Organ failure of kidney, liver, heart, or lung

- Myocardial infarction within the past 6 months

- Cancer likely to cause death within 2 years or less.

12. Subject history indicates high risk of non-compliance (e.g., substance abuse,
psychosocial issues, etc.)

13. Subject has a known history contraindicating contrast dye or iodine that cannot be
pre-medicated prior to coiling procedure (vs. sensitivity which can be safely
controlled by antihistamine, steroid, etc.). Medical clearance will be needed for this
issue.

14. Patients who are unable to complete scheduled follow up assessments at the enrolling
center due to limited life expectancy (<2 years), co-morbidities or geographical
considerations

15. Subject is currently breast feeding, pregnant or plans to become pregnant in the next
2 years.

16. Major surgical procedure or trauma within 30 days prior to randomization

17. The patient is currently enrolled in another clinical study (device or drug).

18. More than one aneurysm needing treatment at the same time.