Sapien 3 Transcatheter Aortic Valve Replacement in Young Aortic Valve Stenosis Patients From China

Inclusion Criteria: Subjects must meet ALL of the following inclusion criteria to be eligible for participation: * 50 years of age or older but ≤70 years old at time of consent. * Severe AS, defined as follows: a) For symptomatic patients: i) Aortic valve area ≤1.0 cm2 (or aortic valve area index of ≤0.6 cm2/m2), OR mean gradient ≥40 mm Hg, OR Maximal aortic valve velocity ≥4.0 m/sec by transthoracic echocardiography at rest b) For asymptomatic patients: i) Very severe AS with an aortic valve area of ≤1.0 cm2 (or aortic valve area index of ≤0.6 cm2/m2), AND maximal aortic velocity ≥5.0 m/sec, or mean gradient ≥60 mm Hg by transthoracic echocardiography at rest, OR ii) Aortic valve area of ≤1.0 cm2 (or aortic valve area index of ≤0.6 cm2/m2), AND a mean gradient ≥40 mm Hg or maximal aortic valve velocity ≥4.0 m/sec by transthoracic echocardiography at rest, AND an exercise tolerance test that demonstrates a limited exercise capacity, abnormal BP response, or arrhythmia OR iii) Aortic valve area of ≤1.0 cm2 (or aortic valve area index of ≤0.6 cm2/m2), AND mean gradient ≥40 mmHg, or maximal aortic valve velocity ≥4.0 m/sec by transthoracic echocardiography at rest, AND a left ventricular ejection fraction \<50%. * Tricuspid aortic valve stenosis and type-1 bicuspid aortic valve anatomy confirmed by MDCT. * The subject and the treating physician agree that the subject will return for all required post-procedure follow-up visits. * Adequate iliofemoral access and acceptable level of vessel calcification and tortuosity for safe device implant. * The study patient 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. Exclusion Criteria: Subjects are NOT eligible for participation if they meet ANY of the following exclusion criteria: * Any of the following: a. no calcification; b. challenging calcification based on physician's experience and discretion (Case Review Board would decide whether to exclude challenging calcification cases). * Aortic valve is a congenital unicuspid valve, congenital Type-0 or Type-2 bicuspid valve, or quadricuspid valve. * Severe femoral, iliac or aortic atherosclerosis, calcification, coarctation, aneurysm or tortuosity, which prevents transfemoral TAVR. * Evidence of an acute myocardial infarction ≤ 1 month (30 days), with evidence of myocardial necrosis in a clinical setting consistent with acute myocardial ischemia. * Need for open heart surgery (including severe aortic regurgitation, mitral regurgitation or stenosis, or tricuspid regurgitation, congenital heart disease, AF, complex coronary artery disease). * Aortic disease: a. bicuspid aortic valve with an ascending aorta diameter ≥ 45mm b. tricuspid aortic valve with an ascending aorta diameter ≥ 50mm. * Pre-existing mechanical or bioprosthetic valve in any position. * Hemodynamic or respiratory instability requiring inotropic support, mechanical ventilation or mechanical heart assistance within 30 days of the screening visit. * Emergency interventional/surgical procedures within 30 days of the valve implant procedure. * Hypertrophic cardiomyopathy with or without obstruction. * Ventricular dysfunction with LVEF \< 30%. * Cardiac imaging (echo, CT, and/or MRI) evidence of ventricular mass, thrombus or vegetation. * Inability (including allergy) to heparin, iodine contrast agent, warfarin or NOAC, aspirin or clopidogrel. * Stroke or transient ischemic attack (TIA) within 180 days of the valve implant procedure. * Renal replacement therapy at the time of screening. * Severe lung disease (FEV1 \< 50% predicted) or currently on home oxygen. * Estimated life expectancy \< 24 months. * Currently participating in an investigational drug or another device study. Note: Trials requiring extended follow-up for products that were investigational, but have since become commercially available, are not considered investigational trials. Observational studies are not considered exclusionary.