PROTECT TAVI - Prospective Randomized Outcome Study in TAVI Patients Undergoing Periprocedural Embolic Cerebral Protection With the Sentinel™ Device

Inclusion Criteria: * Patients with aortic stenosis and indication for transfemoral aortic valve replacement * Freedom of significant stenosis in the area of Truncus brachiocephalicus and left A. carotis (CT) * Necessary vessel diameter of 6.5-10 mm in the area of A. carotis communis sinistra and 9-15 mm in the area of Truncus brachiocephalicus (for delivery of protection system) * Anomalies of aortic arch ("bovine arch" variants): 1. Direct outflow of left A. carotis communis out of Truncus brachiocephalicus 2. Conjoint origin of Truncus brachiocephalicus and left A. carotis communis out of aortic arch * The patient has provided written informed consent Exclusion Criteria: * Apoplexy/ TIA during the last ½ year * Severe carotid stenosis (\>70%) * Symptomatic or asymptomatic carotid stenosis with necessity of TEA or stenting * Relevant psychiatric diseases * Severe/ relevant visual, auditory or cognitive deficits which impede targeted anamnesis, neurologic evaluation or consenting. * Severe neurodegenerative or progressive neuromuscular disease and state after severe craniocerebral injury with permanent neurologic sequelae and structural cerebral diseases * Pronounced kinking/ stenosis or calcification in the area of the right A. radialis/ brachialis/ subclavia, which impede implantation of the cerebral protection system * Significant stenosis, relevant calcifications, dissections or aneurysmatic alterations in the area of Truncus brachiocephalicus and/or A. carotis communis sinistra. * Contraindications for MRI: among others the presence of a non-MRI-compatible pacemaker or defibrillator, metal implants in the area to be evaluated, metal fragments in the craniocerebral area, allergies, claustrophobia. * Vessel alterations which impede among others the introduction of a 6 French sheath: 1. Inadequate perfusion in the area of the right upper extremity (pathologic Allen´s test, vessel obstructions, peripheral vascular disease) 2. Hemodialysis shunt, grafts, or arteriovenous fistulas in the area of right upper extremity * Acute myocardial infarction ≤ 1 month prior to the planned procedure * Every contraindication for the execution of a transfemoral TAVI * Aortic annulus \<19 or \>29 mm * Combined aortic vitium with predominant insufficiency. * Severly reduced leftventricular function ≤ 20% * Patients who are planned for a hybrid procedure (e.g. conventional operation and TAVI or simultaneous coronary intervention at coronary artery disease needing intervention) 14 days prior to the planned study procedure * Intracardiac thrombus, hematoma, tumor or vegetations confirmed by echocardiography * Endocarditis * Planned concomitant procedure for atrial fibrillation (operative or via catheter ablation) during the follow up phase * Need for emergency procedure * Chronic drug-, medication or alcohol abuse * Consuming disease * Life expectancy \< 1 year * Dialysis dependency * Patient with legal incapacity, who is not able to understand the essence, meaning and consequences of the study * Participation in other interventional clinical trials in the month of study start or planned participation during the participation of this study