This study focuses on individuals who have been recommended for aortic valve replacement for aortic stenosis (disease of the aortic valve). The purpose of the study is to collect and compare the safety and performance of self-expanding (SE) versus balloon expandable (BE) transcatheter aortic valve replacement (TAVR) in patients with small aortic valve. Aortic stenosis occurs if the valve becomes too narrow, causing less blood to flow through and the heart to work harder to pump the same amount of blood with each beat.

A procedure to replace the diseased aortic valve is the standard treatment for aortic stenosis. This can be done by open heart surgery (also called surgical aortic valve replacement), or TAVR, which does not require open heart surgery. Participants in this study will have TAVR. In a TAVR procedure, the transcatheter aortic valve replacement device is inserted through a flexible tube (catheter), which is inserted through an incision in the groin and threaded through the blood vessel. Participants will receive either self-expanding (Evolut) or balloon-expandable (Sapien) devices in order to replace the aortic valve. Researchers will compare the valves to learn which works better in these patients.