This clinical study is a prospective、single arm and exploratory study, to explore the feasibility and safety of MitrAssist TRISKELE® transcatheter aortic valve system in the treatment of patients with severe aortic stenosis.

This study was a prospective、single arm clinical trial design. For patients with surgical contraindications or high-risk symptomatic severe aortic stenosis, MitrAssist TRISKELE® transcatheter aortic valve system was performed by aortic valve replacement. Patients were followed up 30 days (± 7 days) after operation for the feasibility and safety analysis to explore the test device in patients with surgical contraindications or high-risk symptomatic severe aortic stenosis.In this study, a clinical trial institution meeting the national qualification is planned to be selected as the clinical research center, and 7 patients are planned to be selected.

The success rate of operation 30 days after operation was taken as the main evaluation index and the success of device implantation, the result of echocardiography evaluation of valve function, the improvement rate of NYHA cardiac function classification, six minute walking distance and the score of Kansas City Cardiomyopathy Questionnaire were taken as the secondary evaluation indexes, to evaluate clinical effectiveness of TRISKELE® transcatheter aortic valve system; Adverse events, serious adverse events, major cardiovascular and cerebrovascular adverse events, device defects, vital signs and laboratory examination results were used as safety indicators to evaluate the safety of the test device .

Inclusion Criteria:

1. Age ≥ 70 years old;
2. Patients with symptomatic severe aortic stenosis (echocardiographic mean pressure gradient across aortic valve ≥ 40mmhg, or blood flow velocity across aortic valve ≥ 4.0m/s, or aortic valve area < 0.8cm2, or effective aortic valve area index < 0.5cm2/m2);
3. Patients with biological valve decay meeting the criteria in (2) above;
4. NYHA grade ≥ grade II;
5. The life expectancy after artificial valve implantation is more than 1 year;
6. Patients who are anatomically suitable for transcatheter aortic valve implantation;
7. Two or more cardiothoracic surgeons evaluate and record it as surgical contraindication or as high-risk surgery and unsuitable for routine surgery;
8. Patients who can understand the purpose of the trial, voluntarily participate in and sign informed consent, and are willing to accept relevant examination and clinical follow-up.

Exclusion Criteria:

1. Acute myocardial infarction occurred within 30 days before this treatment (WHO definition: Q-wave MI, or non-Q-wave MI with elevated creatine kinase isoenzyme and troponin T);
2. Patients whose aortic root anatomy and lesions are not suitable for artificial valve implantation;
3. Compound aortic valve disease (aortic stenosis with severe regurgitation); Severe mitral regurgitation;
4. Hematological malignancies, hemophilia and other coagulation disorders;
5. Hemodynamic instability, requiring mechanical cardiac assistance;
6. Emergency operation for any reason;
7. Obstructive hypertrophic cardiomyopathy;
8. Severe left ventricular dysfunction, left ventricular ejection fraction (LVEF) < 30%;
9. Severe right ventricular dysfunction;
10. Echocardiography showed the presence of intracardiac mass, thrombus or vegetations;
11. Active peptic ulcer or upper gastrointestinal hemorrhage within 3 months;
12. Allergic to nickel titanium alloy, stainless steel alloy, PU (polyurethane), or contrast agent; Unable to tolerate anticoagulant and antiplatelet therapy;
13. Cerebrovascular events (CVA) occurred within 3 months, including ischemic stroke and hemorrhagic stroke, excluding transient ischemic attack (TIA);
14. Vascular diseases affecting the instrument approach;
15. Infective endocarditis in active phase or other active infections;
16. Those who have participated in clinical trials of other drugs or medical devices before enrollment and have not reached the time limit of the main research endpoint.