Citadel Embolization Device Study

Open to people ages 18-80

1. Age is ≥18 and ≤80 years
2. Has a single, unruptured or ruptured target intracranial aneurysm that is suitable for endovascular treatment Definition: For the purposes of this study, a ruptured intracranial aneurysm is defined as one with CT/MRI/LP evidence of subarachnoid hemorrhage attributed to the index aneurysm within the last 60 days.
3. Aneurysm morphology is saccular
4. Aneurysm size is between 6-12 mm
5. Has a wide-neck, saccular aneurysm, either bifurcation or sidewall, with a dome to neck ratio <2 or neck ≥4 mm
6. If the target intracranial aneurysm is classified as ruptured, patient must be neurologically stable with a Hunt & Hess Score of 1 or 2.
7. Must be willing to comply with protocol required procedures and follow up
8. Subject or LAR must be willing to sign and date an IRB approved written informed consent prior to initiation of any screening or study procedures

1. Target aneurysm has been previously treated
2. Target aneurysm is in any extradural location, including the extradural cavernous segment
3. Has vessel characteristics, tortuosity or morphology or unfavorable aneurysm morphology (e.g., determined from baseline or preprocedure imaging, or which may be evidenced by excessive resistance felt during the procedure) that would preclude safe endovascular access to the target aneurysm necessary for treatment with the study device
4. Has significant intracranial atherosclerotic disease or stenosis determined from baseline or pre-procedure imaging
5. If the target intracranial aneurysm is classified as ruptured, patient is neurologically unstable or has a Hunt & Hess Score of ≥ 3
6. Has a history of intracranial vasospasm not responsive to medical therapy
7. Has undergone coiling or stenting of a non-target intracranial aneurysm within 30 days prior to study treatment or has a non-target intracranial aneurysm that is expected to be treated within 12 months following the treatment of the target aneurysm
8. Treatment with flow diverting stent implant is anticipated

9. A planned, staged procedure is anticipated

   10. Has Moya-Moya disease, arteriovenous malformation(s), arteriovenous fistula(e),

   intracranial tumor(s), intracranial hematoma(s), any other intracranial vascular malformation, or any previous major intracranial surgery

   11. Has had a recent (within 90 days) ischemic stroke, TIA, or intracranial hemorrhage 12. Has a baseline mRS score ≥2 13. Has a known coagulopathy or is on chronic anticoagulant therapy 14. Is pregnant or intends to become pregnant during the study or is breastfeeding 15. Is concurrently involved in another study that could affect outcomes of IA treatment 16. Has evidence of active cancer, terminal illness, high risk of embolic stroke, atrial

   fibrillation, significant co-morbidities, major surgery ≤ 30 days pre-procedure, psychiatric disorders, substance abuse, or a life expectancy of less than 5 years

   17. Has a contraindication to angiography, radiographic contrast agents, or any

   medications that are typically used during the procedure, and any other contraindications listed in the Investigational DFU