Neuroform Atlas IDE Study

The study is a prospective, multicenter, open-label, single arm trial designed to demonstrate
the potential treatment of wide neck, intracranial, saccular aneurysms with the Next
Generation Neuroform Stent System with any approved embolic coils currently on the market.
The study will evaluate the percent occlusion of the treated target lesion on angiography in
the absence of retreatment, or parent artery stenosis at the target location at 12 months.
Subjects with documented wide neck, intracranial, saccular aneurysms arising from a parent
artery may potentially benefit from stent assisted coiling, provided they meet the other
eligibility criteria.

Inclusion Criteria:

1. Subject is between 18 and 80 years of age

2. Documented wide neck (neck ≥ 4 mm or a dome-to-neck ratio of < 2), intracranial,
saccular aneurysm arising from a parent vessel with a diameter of ≥ 2mm and ≤ 4.5 mm,
which will be treated with bare metal coils

3. Subject or legal representative is willing and able to provide informed consent

4. Subject is willing and able to comply with protocol follow-up requirements

Exclusion Criteria:

1. Known multiple untreated cerebral aneurysms, other than non-target blister aneurysm,
infundibulum, or aneurysm measuring <3mm for each of three dimensions assessed
(height, width, and depth) that will not require treatment during the study period

2. Target lesion is a blister aneurysm, infundibulum, or aneurysm measuring <3mm for each
of three dimensions assessed (height, width, and depth)

3. Target aneurysm that will require an Investigator to intentionally leave a neck
remnant in order to preserve blood flow in a bifurcation or branch

4. Coiling or stenting of a non-target intracranial aneurysm within 30 days prior to
study treatment

5. Target aneurysm is in the anterior circulation proximal to the superior hypophyseal
ICA

6. Acute target aneurysm rupture less than 14 days prior to study treatment

7. Hunt and Hess score ≥ 3 or a premorbid mRS score ≥4

8. An admission platelet count of <50,000, any known coagulopathy, or an International
Normalized Ratio (INR)>3.0 without oral anticoagulation therapy

9. A known absolute contraindication to angiography

10. Evidence of active cancer, terminal illness or any condition which, in the opinion of
the treating physician, would/could prevent subject from completing the study (e.g., a
high risk of embolic stroke, atrial fibrillation, co-morbidities, psychiatric
disorders, substance abuse, major surgery ≤ 30 days pre-procedure, etc.)

11. Known absolute contraindication to the use of required study medications or agents
(e.g., heparin, aspirin, clopidogrel, and radiographic contrast agents, etc.)

12. Female subject who is pregnant or intends to become pregnant during the study

13. Moya-Moya disease, arteriovenous malformation(s), arteriovenous fistula(e),
intracranial tumor(s), or intracranial hematoma(s) (unrelated to target aneurysm)

14. Significant atherosclerotic stenosis, significant vessel tortuosity, vasospasm
refractory to medication, unfavorable aneurysm morphology or vessel anatomy, or some
other condition(s) that, in the opinion of the treating physician, would/could prevent
or interfere with access to the target aneurysm and/or successful deployment of the
Neuroform Atlas™ Stent

15. Previous treatment (e.g., surgery, stenting) in the parent artery that, in the opinion
of the treating physician, would/could prevent or interfere with successful use of the
Neuroform Atlas™ Stent System and/or successful adjunctive deployment of embolic coils

16. Previous stent-assisted coiling of the target aneurysm