Evaluation of Effectiveness and Safety of Evolut R Valve In Patients With Pure Aortic Regurgitation

Inclusion Criteria: 1. Patients must have co-morbidities such that the principal investigator and co-investigator concur that the predicted risk of operative mortality is ≥15% (STS score ≥10 OR Logistic EuroSCORE ≥20%). A candidate who does not meet \[the STS score criteria ≥ 10 OR Logistic EuroSCORE ≥20%\] can be included in the study if a peer review by at least two investigators concluded and documented that the patient's predicted risk of operative mortality is ≥15% from old age, severe frailty or STS score ≥8. In this case, all evidence must be documented in the study case report form as well as in the patient medical record. 2. There is a formal agreement by a cardiac surgeon, echo part cardiologist and interventional cardiologist according to the relevant guideline. 3. The subject does not have severe degenerative aortic stenosis and do have severe aortic regurgitation. 4. The subject or the subject's legal representative has been informed of the nature of the study, agrees to its provisions and has provided written informed consent as approved by the Institutional Review Board (IRB) of the respective clinical site. 5. The subject agrees that the subject will keep in touch with study team for all required post-procedures like angiography or transesophageal echography. 6. The subject agrees that the subject will cooperate with study team for all required post-procedure visits. 7. The subject's age is 20 or more. Exclusion Criteria: 1. Evidence of an acute myocardial infarction ≤ 1 month before the intended treatment(defined as: Q wave MI, or non-Q wave MI with total CK elevation of CK-MB ≥ twice normal in the presence of MB elevation and/or troponin level elevation (WHO definition). 2. Any therapeutic invasive cardiac procedure performed within 30 days of the index procedure, (or 6 months if the procedure was a drug-eluting coronary stent implantation). 3. Blood dyscrasias as defined: leukopenia (WBC\<3000 mm3), acute anemia (Hb\<9 mg%), thrombocytopenia (platelet count \<50,000 cells/mm³), history of bleeding diathesis or coagulopathy. 4. Untreated clinically significant coronary artery disease requiring revascularization. 5. Need for emergency surgery for any reason. 6. Echocardiographic evidence of intracardiac mass, thrombus or vegetation. 7. Active bacterial endocarditis or other active infections. 8. Active peptic ulcer or upper GI bleeding within the prior 3 months. 9. A known hypersensitivity or contraindication to aspirin, heparin, ticlopidine (Ticlid), or clopidogrel (Plavix), or sensitivity to contrast media, which cannot be adequately pre-medicated. 10. Recent (within 6 months) cerebrovascular accident (CVA) or a transient ischemic attack (TIA). 11. Life expectancy \< 12 months due to non-cardiac comorbid conditions. 12. Significant aortic disease, including abdominal aortic or thoracic aneurysm defined as maximal luminal diameter 5cm or greater; marked tortuosity (hyperacute bend or angle of aortic arch ≥200 degree),aortic arch atheroma (especially if thick \[\> 5mm\], protruding or ulcerated) or narrowing (especially with calcification and surface irregularities) of the abdominal or thoracic aorta, severe "unfolding" and tortuosity of the thoracic aorta (applicable for transfemoral patients only). 13. Root disease including annuloaortic ectasia or aneurysm of root or sinus. 14. Iliofemoral vessel characteristics that would preclude safe placement of introducer sheath such as severe obstructive calcification, severe tortuosity(with moderate or severe calcification and two or more severe curve (angle ≥90°) (applicable for transfemoral patients only). 15. Pregnant(positive result from pregnancy test conducted during screening visit and within prior 2 weeks of valve replacement) or lactating women.