The purpose of this study is to conduct the clinical investigation of the HeartHill Medical's polymer aortic valve, namely PoliaVavle，to collect evidence on the device's safety and performance. This prospective, multicenter, randomized controlled, non inferiority clinical trial is expected to enroll 198 subjects and conduct a 1:1 random grouping. The experimental group will use polymer material surgical aortic valves（PoliaVavle, HeartHill Medical, Suzhou China) for aortic valve replacement, while the control group will use bovine pericardial biological valves for aortic valve replacement.

Inclusion Criteria:

1. The subjects are aged ≥18 years old;
2. The subjects understand the nature and purpose of the study, voluntarily participate, and sign the informed consent form. They agree to comply with the trial requirements, cooperate with surgical treatment and follow-up, and consent to relevant follow-up inquiries and examinations;
3. The subjects have been confirmed to have severe aortic valve stenosis and/or regurgitation (also known as insufficiency) through echocardiography;
4. According to the 2020 ACC/AHA guidelines for the management of patients with valvular heart disease, the subjects meet the indications for surgical aortic valve replacement and preoperative assessment recommends surgical aortic valve replacement.

Exclusion Criteria:

1. Other valve diseases with surgical indications, such as severe mitral regurgitation, severe tricuspid regurgitation, moderate or greater mitral stenosis, or a history of previous aortic or other valve replacement surgery;
2. Other severe cardiovascular conditions with surgical indications, such as Stanford A-type aortic dissection, aortic sinus aneurysm (sinus diameter > 5.0cm), hypertrophic obstructive cardiomyopathy, diffuse three-vessel coronary artery disease, or placement of a left ventricular assist device in end-stage heart failure;
3. End-stage heart failure that is not reversible even with aortic valve surgery, such as severe left ventricular dysfunction (LVEF < 25%), or severe heart failure that cannot be corrected, or severe pulmonary hypertension assessed by right heart catheterization, with planned postoperative Impella, IABP, or left ventricular assist;
4. Preoperative decompensated heart failure, cardiogenic shock, malignant arrhythmias, etc., requiring mechanical circulatory support, mechanical ventilation, or emergency surgery;
5. Active endocarditis within the past 3 months or the presence of cardiac vegetations;
6. Severe acute myocardial infarction or history of cerebrovascular accidents within the past 3 months (excluding lacunar infarcts);
7. Severe renal insufficiency (glomerular filtration rate < 30mL/min) or end-stage renal disease requiring long-term dialysis;
8. Liver dysfunction or gastrointestinal malnutrition-related diseases;
9. Active bleeding, bleeding tendencies, or patients unable to receive anticoagulant therapy;
10. Severe respiratory or ventilatory dysfunction requiring continuous oxygen therapy;
11. Poor compliance or cognitive impairment (such as coma, Parkinson's disease, dementia, substance abuse), inability to follow study requirements or refusal to participate in follow-up visits;
12. Other conditions with an expected lifespan of less than 1 year, such as malignancies and immunodeficiency diseases;
13. Other situations not suitable for artificial aortic valve replacement or participation in this trial.