To date, no formal, randomized, prospective, head-to-head comparisons of surgical aortic valve replacement (SAVR) versus transcatheter aortic valve replacement (TAVR) have been undertaken in the severe aortic stenosis (AS) population with small aortic annuli. Objectives of the present study are to compare the hemodynamic performance (incidence of severe PPM and ≥ moderate AR) and clinical outcomes (death, stroke, major or life threatening bleeding) between TAVR and SAVR in patients with severe AS and small aortic annuli.

This is a prospective, multicenter, randomized open-label trial including patients with severe AS and small aortic annulus (mean aortic annuli diameter ˂23mm and minimal diameter ≤21.5mm, evaluated by 3D-CT or 3D-TEE). Patients will be randomized in a 1:1 fashion to either TAVR or SAVR. The TAVR procedure will be performed with the ACURATE neo Aortic Valve, the Edwards SAPIEN 3 valve (20, 23 or 26mm) or the CoreValve Evolut R or Evolut PRO valve system (23 or 26 mm).New iterations of these valve models may also be included. The SAVR procedure will be performed using standard techniques, with no limitation in terms of type and size of the valve prosthesis or surgical procedure (e.g. enlargement of the aortic root). For both TAVR and SAVR, the choice of the type and size of valve, access route (for TAVR), utilization of additional procedures such as root enlargement will be left at the discretion of heart team of the site treating the patient.

Inclusion Criteria:

• Patients ≥65 years-old diagnosed with severe AS (defined as: jet velocity ≥ 4.0 m/s or mean gradient ≥ 40 mmHg or velocity ratio <0.25 AND aortic valve area ≤ 1.0 cm2 or aortic valve area index ≤ 0.6 cm2/m2; OR mean gradient >30 mmHg AND aortic valve area ≤ 1.0 cm2 or aortic valve area index ≤ 0.6 cm2/m2 AND >1200 Agatston units for women or >2000 Agatston units for men as determined by non-contrast CT).
• Small aortic annulus defined as a mean aortic annulus diameters ˂23 mm and a minimal aortic annulus diameter of ≤21.5 mm as measured by 3D-computed tomography (CT) and/or 3D-transesophageal echocardiography (TEE).

Exclusion Criteria:

• Prohibitive surgical risk as determined by the Heart Team
• Porcelain aorta
• Aortic root dilatation >45 mm
• Coronary artery disease (CAD) not treatable by percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG), or SYNTAX score >32 (in the absence of prior revascularization) or severe left main disease
• Non-calcific aortic stenosis
• Severe mitral regurgitation
• Moderate-to-severe tricuspid regurgitation requiring surgical repair
• Prior surgical valve in aortic position