To observe and evaluate the safety and efficacy of TaurusOne® transcatheter aortic valve system in patients with severe calcific aortic stenosis through a prospective, multicenter clinical trial using objective performance criteria.

Inclusion Criteria:

• Patients who voluntarily participate and sign the informed consent and are able to comply with the entire trial process;

• Age ≥ 70 years;

• Patients with severe calcific aortic stenosis confirmed by echocardiography (Transaortic flow velocity ≥ 4.0 m/s, or aortic-valve gradient ≥ 40 mmHg (1 mmHg = 0.133 kPa), or aortic valve area < 0.8 cm2, or effective orifice area < 0.5 cm2/m2);

• Patients who have symptoms obviously caused by aortic stenosis, NYHA Class II or worse;

• Patients who are unsuitable for conventional surgery evaluated by the cardiac team (including at least two cardiovascular surgeons) [13] *;

• Life expectancy after implantation of prosthetic valve is more than one year evaluated by the cardiac team (including at least two cardiac surgeons);

• Aortic annulus diameter ≥ 18 mm and ≤ 29 mm (measured by cardiac CT);

• Ascending aorta diameter < 50 mm

  *: If the patient meets any of the following criteria judged by a multidisciplinary cardiac team composed of cardiologists and cardiovascular surgeons, radiologists, anesthesiologists, etc. (at least two cardiovascular surgeons), the patient will be identified as unsuitable for conventional surgery (at least STS ≥ 8 points):

• Estimated risk of surgery-related death or disability > 50% within 1 year;

• ≥3 major organ damage that could not be improved by surgery;

• Obstacles related to surgical procedures judged as serious

Exclusion Criteria:

• Patients with bacteremia or toxemia;
• Previous endocarditis or active endocarditis;
• Acute myocardial infarction (Q-wave MI, or non-Q-wave MI with elevated creatine kinase isoenzyme and troponin T) within 30 days;
• Any intracardiac mass, left ventricular or atrial thrombus, vegetation on echocardiography;
• Symptomatic atrial fibrillation that cannot be improved by drug therapy;
• Familial hypertrophic cardiomyopathy;
• Mitral or tricuspid valve insufficiency (grade II regurgitation or higher);
• Previous aortic valve graft (mechanical or bioprosthetic valve);
• Known allergies to contrast agents, aspirin, heparin, ticlopidine drugs, nitinol shape memory alloy, or bovine products;
• Known contraindications or allergies to anticoagulant regimens, or inability to use anticoagulants throughout the trial;
• Other serious diseases that may reduce life expectancy to less than 12 months (such as clinically recurrent or metastatic cancer, congestive heart failure, etc.);
• Current substance abuse problems (e.g., alcohol, cocaine, heroin, etc.);
• Scheduled to undergo surgery that may result in protocol noncompliance or confounding in data interpretation.
• Cerebrovascular accident (CVA) in the past 6 months;
• Patients with common carotid artery or internal carotid artery or vertebral artery stenosis (>70%);
• White blood cell count <3×109/L, platelet count <50×109/L;
• Hemoglobin < 90 g/L;
• Patients with severe coagulopathy;
• Severe left ventricular dysfunction, left ventricular ejection fraction < 20%;
• Abdominal or thoracic aortic aneurysm;
• Hepatic encephalopathy or acute active hepatitis;
• On dialysis or baseline creatinine level > 2.5 mg/dL (221 μ mol/L);
• Bleeding tendency or history of coagulation disease or refusal of blood transfusion;
• Patients with active peptic ulcer or active gastrointestinal (GI) bleeding;
• Patients with neurological diseases that seriously affect mobility and activities of daily living;
• Patients with mental illness or psychological disorders who are unable to communicate effectively;
• Patients who need emergency surgery for any reason;
• Patients who have participated in other drug or medical device clinical trials within 3 months prior to screening;
• Other conditions that make the patient ineligible to participate in this clinical trial in judgement of investigators