Cohort study for the treatment of unruptured intracranial aneurysms with flow diverters

Suitability for FD treatment or alternative treatment will be identified according to the following inclusion criteria:
- unruptured intracranial aneurysm of internal carotid artery;
- unfavourable dome neck configuration (≤2), or neck ≥4 mm, or maximum aneurysm diameter ≥10 mm; or tandem aneurysms with any configuration; multisegmental disease;
- ≥18 years;
- modified Rankin Scale (mRS) ≤2;
- patients willing to provide written informed consent and comply with follow up requirements.
Patients eligible for FD but treated otherwise in the Radboudumc and patients eligible for this study and treated with FD in other centres should also be included in the study. A registry will be kept of patients treated with FD who did not meet the inclusion criteria for this study.

- intracranial hemorrhage within 30 days;
- presence of untreated ruptured intracranial aneurysm;
- ≥1 intracranial aneurysm except the target one which requires treatment within 12 months;
- contra-indication for dual antiplatelet therapy;
- known allergy or inadequate response to aspirin, heparin, clopidogrel, ticagrelor or prasugrel, other anti-platelet or P2Y12 agents or to general anesthesia (platelet reactivity will be assessed prior to the inclusion in patients who require anti-platelet or P2Y12 agents following the treatment);
- bifurcation aneurysm (e.g. pcom aneurysm with fetal or intermediate configuration where pcom cannot be occluded);
- immunosuppressive disease;
- active infectious disease (e.g. endocarditis, meningitis);
- platelet count < 100 x 103 cells/mm3 or known platelet dysfunction at time of enrollment;
- female of child-bearing potential who are unable to take adequate contraceptive precautions, are known to be pregnant, or are currently breastfeeding an infant;
- intracranial aneurysm correlating to arteriovenous malformation, dissecting aneurysms;
- patient with another unrelated intracranial disease and patients with any type of malignancy;
- major surgery within previous 30 days or planned in the next 120 days after enrolment;
- patient with a periprocedural International Normalized Ratio (INR)≥ 1.5;
- patient with any condition that, in the opinion of the treating physician, would place the participant at a high risk of embolic stroke or with any medical co-morbidity likely to affect the outcome (e.g. pulmonary disease, uncontrolled diabetes, protrombotic conditions, e.g. factor 5 Leiden);
- patient with a life threatening allergy to iodinated contrast media (patients with itching or rash as a reaction to contrast can be included if properly prophylactically treated);
- patient who is currently participating in another clinical research study involving an investigational product;
- stenting, angioplasty, or endarterectomy of an extracranial (carotid or vertebral artery) or intracranial artery within 30 days prior to the treatment date;
- unstable neurological deficit (i.e. worsening or improvement of clinical condition in the last 30 days unrelated to the aneurysm);
- patient who has participated in a drug study within the last 30 days;
- inability to understand the study or history of non-compliance with medical advice;
- patient who has had a previous intracranial procedure associated with the target aneurysm such that access and placement of an investigational device would be compromised.