The purpose of this post-market registry is to collect and monitor ongoing safety and performance clinical data of the ACURATE neo™ Aortic Bioprosthesis, and the ACURATE TF™ Transferral Delivery System, when used as per IFU.

The primary objective of this post-market registry is to further evaluate the safety and performance of the ACURATE neo™ Aortic Bioprosthesis and the ACURATE TF™ Transferral Delivery System in 500 consented patients with severe aortic stenosis and treated according to the instructions for use (IFU).

Examinations to evaluate the aortic valve regurgitation performed as standard of care in patients undergoing transcatheter aortic valve replacement will be analyzed by an external Core Laboratory. These examinations are limited to echocardiography and/or contrast aortography assessments.

The secondary objective is to collect adverse events and evaluate them according to the VARC-2 consensus document.

Inclusion Criteria:

1. Patient is included in the registry if eligible for transcatheter treatment of severe aortic stenosis with the ACURATE neo™ Aortic Bioprosthesis and ACURATE TF™ Transfemoral Delivery System as per the Instructions for Use (Patients which are included but treated outside of the approved indication will be followed for safety reasons).
2. Patient is willing to participate in the study, provides signed Informed Consent/Data Authorization Form and authorizes the sharing of data in the registry. Patient agrees that anonymized imaging data will be sent to and analyzed by an external Core Laboratory.
3. The treating physician should ensure the subject will return for all required post procedure follow-up visits.

Exclusion Criteria:

1. Patients are excluded from the registry if they are not eligible for transcatheter treatment of severe aortic stenosis with the ACURATE neo™ Aortic Bioprosthesis and ACURATE TF™ Transfemoral Delivery System as per the Instructions For Use.

All patients eligible for transcatheter treatment of severe aortic stenosis with the ACURATE neo™ Aortic Bioprosthesis and ACURATE TF™ Transfemoral Delivery System according to the indication in the Instruction for Use.

The ACURATE neo™ Aortic Bioprosthesis and its Delivery System are indicated for use in patients 75 years of age and older with severe aortic stenosis (mean aortic gradient > 40 mmHg or peak jet velocity > 4.0 m/s or aortic valve area < 1.0 cm2) for whom conventional surgical aortic valve replacement is considered high risk for mortality or who are not operable as determined either by a heart team consisting of a cardiologist and surgeon or by the following risk assessments:

Logistic EuroSCORE > 20%

STS score > 10%

The data and study protocol for this clinical trial may be made available to other researchers in accordance with the Boston Scientific Data Sharing Policy (http://www.bostonscientific.com/en-US/data-sharing-requests.html).