Echo-Guided vs Fluoroscopy-Guided Transcatheter Aortic Valve Replacement in Patients With Aortic Stenosis（ECHO-TAVR）

Inclusion criteria

• 1. Patients aged 70 years or older with obvious clinical symptoms or a left ventricular ejection fraction less than 50% due to severe aortic valve stenosis (aortic valve orifice area < 1.0 cm² or peak velocity ≥ 4.0 m/s or mean transvalvular pressure ≥ 40 mmHg); or patients with obvious clinical symptoms of low blood flow and low pressure difference aortic valve stenosis (effective aortic valve orifice area < 1.0 cm², mean transvalvular pressure difference < 40 mmHg, left ventricular ejection fraction < 50%, stroke volume index < 35 ml/m², and diagnosed as true severe aortic valve stenosis by dobutamine stress test);
• 2. Patients aged 65 years ≤ age < 70 years with severe aortic stenosis who have surgical contraindications or high risks, or have other risk factors such as post-chest radiotherapy, liver failure, diffuse severe aortic calcification, extreme weakness, etc., or patients refuse to undergo routine open-chest surgery;
• 3. The patient's anatomical structure is suitable for TAVR and can tolerate transesophageal ultrasound;
• 4. The patient has signed the informed consent form and is willing to participate in this study.

Exclusion criteria

• 1. Imaging (ultrasound and/or CT and/or MRI) confirmed a lesion, thrombus or calculus in the left ventricle;
• 2. Severe obstruction of the left ventricular outflow tract;
• 3. Severe right ventricular dysfunction;
• 4. Acute myocardial infarction within 30 days before the procedure;
• 5. Active endocarditis history within 180 days before the procedure;
• 6. Inappropriate aortic root anatomy (such as combined aortic dissection, excessive aortic annulus, risk of coronary artery occlusion, etc.);
• 7. Severe calcification and distortion of the surgical approach;
• 8. Left ventricular ejection fraction less than 20%;
• 9. Other cardiac diseases that require concurrent treatment (such as severe mitral regurgitation, atrial fibrillation, etc.);
• 10. History of stroke or transient ischemic attack within 90 days before the procedure;
• 11. Liver cirrhosis or active liver disease;
• 12. Renal insufficiency (creatinine clearance rate < 30 mL/min) and/or undergoing renal replacement therapy;
• 13. Unable to tolerate anticoagulation therapy during or after the procedure;
• 14. Participating in other drug or device research;
• 15. Any emergency or surgical operation within 30 days before the procedure;
• 16. Other severe comorbidities, even if the valve stenosis is corrected, the expected life expectancy is less than 1 year;
• 17. Other conditions deemed unsuitable for TAVR surgery by the cardiac team.