NAUTILUS CE-mark Trial of the FLOWer Cerebral Embolic Protection Device

Inclusion Criteria: 1. Subjects of age ≥ 18 years 2. Subject is scheduled to undergo transfemoral aortic valve implant (TAVI) procedure on a stenotic native aortic valve and is qualified based on pre-operative CT-scan examination (trans-thoracic echocardiogram (TTE) can be used as confirmatory assessment) 3. Subject anatomy with Ilio-femoral artery segment compatible with a 12 F device catheter size 4. The subject and the treating physician agree that the subject will undergo the scheduled pre-procedural testing and return for all required post-procedure follow-up visits 5. The subject, or legally authorized representative, has been informed of the nature of the study, agrees to its provisions and has provided written informed consent, approved by the appropriate Medical Ethics Committee (EC) or Institutional Review Board (IRB) Exclusion Criteria: Clinical exclusion criteria (preoperative screening) 1. Subjects with hypercoagulable state that cannot be corrected by additional periprocedural heparin 2. Subjects with contraindication to cerebral MRI 3. Subjects with a history of a stroke or transient ischemic attack within the prior 6 months 4. Subjects with known diagnosis of acute myocardial infarction (AMI) within 30 days preceding the index procedure 5. Renal insufficiency (creatinine \> 3.0 mg/dL or Glomerular Filtration Rate GFR \< 30) and/or renal replacement therapy at the time of screening 6. Subjects with a history of bleeding diathesis or coagulopathy or patients in whom anti-platelet and/or anticoagulant therapy is contraindicated, patients who will refuse transfusion, or patients with an active peptic ulcer or history of upper gastrointestinal (GI) bleeding within the prior 3 months 7. Subjects with known hypersensitivity or contraindication to aspirin, heparin/bivalirudin, clopidogrel/ticlopidine, nitinol, stainless steel alloy, and/or contrast sensitivity that cannot be adequately pre-medicated 8. Subject is currently participating in another drug or device clinical study or has other medical illnesses that may cause the subject to be non-compliant with the protocol or confound the data interpretation 9. Subjects with a previously implanted prosthetic aortic valve (i.e., planned valve-in-valve with a TAVI) 10. Subject requires an emergent procedure 11. Subject has active major psychiatric disease 12. Subjects with neurodegenerative or other progressive neurological disease or history of significant head trauma followed by persistent neurologic defaults or known structural brain abnormalities 13. Subject has an ejection fraction of 30% or less 14. Subjects with active endocarditis or other systemic infection 15. Subjects undergoing therapeutic thrombolysis 16. Subject is pregnant or lactating. Pregnancy confirmed by positive urine or serum test Computerized Tomographic exclusion criteria (preoperative screening) 1. Subjects with documented friable or mobile atherosclerotic plaque in the aortic arch 2. Subjects with echocardiographic evidence of aortic mass, thrombus or vegetation 3. Subjects with a diameter of the ascending aorta \< 25 and \> 39 mm at baseline CT (measured 10 mm upstream of the first vessel of the brachiocephalic trunk) 4. Subjects undergoing transcatheter aortic valve implantation (TAVI) via the trans-axillary, trans-subclavian, or trans-aortic route 5. Subjects with severe peripheral arterial, abdominal aortic, or thoracic aortic disease that precludes delivery of sheath vascular access 6. Subjects in whom the aortic arch is heavily calcified, severely atheromatous, or severely tortuous