The goal of this observational study is to assess the changes of ascending aortic diameter in patients undergoing transcatheter aortic valve replacement. The main questions it aims to answer are:

1. whether the ascending aortic diameter increases or remains stable after transcatheter aortic valve replacement, especially in patients with preoperative ascending aortic dilatation;
2. the determinants of postoperative ascending aortic dilatation.

Ascending aortic (AA) dilatation occurs frequently in patients with aortic stenosis (AS). For patients who are candidates for transcatheter aortic valve replacement (TAVR), simultaneous repair of a dilatated AA is technically difficult. As the indications for TAVR have extended to low-risk patients and patients with bicuspid aortic valve , AA dilatation should be considered as a new criterion to refine risk stratification in patients undergoing TAVR. In this observational study, we aim to evaluate the changes of AA diameters and identify the determinants post-TAVR AA dilatation.

Inclusion Criteria:

• Severe aortic stenosis defined as an aortic valve area of 1cm2 or less or an indexed aortic valve area of 0.6cm2/m2 or less;
• Presence of clinical symptoms defined as a New York Heart Association functional class of 2 or more;
• High risk of surgical aortic valve replacement;
• Suitability for a transfemoral vascular access.

Exclusion Criteria:

• Dominant aortic regurgitation;
• History of surgical or transcatheter aortic valve replacement;
• History of aortic surgery;
• Connective tissue disorders.

The indication to perform transcatheter aortic valve replacement was based on a consensus by the Institutional Heart Team.