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 ona stenotic native aortic valve and is qualified based on pre-operative CT-scanexamination (trans-thoracic echocardiogram (TTE) can be used as confirmatoryassessment)
3. Subject anatomy with Ilio-femoral artery segment compatible with a 12 F devicecatheter size
4. The subject and the treating physician agree that the subject will undergo thescheduled pre-procedural testing and return for all required post-procedure follow-upvisits
5. The subject, or legally authorized representative, has been informed of the nature ofthe study, agrees to its provisions and has provided written informed consent,approved by the appropriate Medical Ethics Committee (EC) or Institutional ReviewBoard (IRB)

Exclusion Criteria: Clinical exclusion criteria (preoperative screening)

1. Subjects with hypercoagulable state that cannot be corrected by additionalperiprocedural heparin
2. Subjects with contraindication to cerebral MRI
3. Subjects with a history of a stroke or transient ischemic attack within the prior 6months
4. Subjects with known diagnosis of acute myocardial infarction (AMI) within 30 dayspreceding 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 whomanti-platelet and/or anticoagulant therapy is contraindicated, patients who willrefuse transfusion, or patients with an active peptic ulcer or history of uppergastrointestinal (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/orcontrast sensitivity that cannot be adequately pre-medicated
8. Subject is currently participating in another drug or device clinical study or hasother medical illnesses that may cause the subject to be non-compliant with theprotocol or confound the data interpretation
9. Subjects with a previously implanted prosthetic aortic valve (i.e., plannedvalve-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 historyof significant head trauma followed by persistent neurologic defaults or knownstructural 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)
17. Subjects with documented friable or mobile atherosclerotic plaque in the aortic arch
18. Subjects with echocardiographic evidence of aortic mass, thrombus or vegetation
19. 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)
20. Subjects undergoing transcatheter aortic valve implantation (TAVI) via thetrans-axillary, trans-subclavian, or trans-aortic route
21. Subjects with severe peripheral arterial, abdominal aortic, or thoracic aortic diseasethat precludes delivery of sheath vascular access
22. Subjects in whom the aortic arch is heavily calcified, severely atheromatous, orseverely tortuous