The study will be conducted in patients who are undergoing surgical aortic valve replacement on cardiopulmonary bypass. Following surgical access of the native aortic valve and prior to removal of the valve, the native valve will be dilated using a standard valve dilation balloon. The Heart Leaflet Technologies(HLT- Heart Leaflet Technologies Inc.) aortic valve device will be released in the native valve and measurements will be taken of the device relative to the anatomic structures of the heart. Once completed, the implant is removed from the native valve and the surgical valve replacement procedure is completed.

The purpose of this study is to confirm that the dimensions of the HLT valve are appropriate for patients with aortic valve stenosis.

Aortic valve stenosis is a disease in which the leaflets of the aortic valve become scarred and calcified. This leads to a severe narrowing of the valve orifice, which causes chest pain, heart failure and eventually death. The condition is currently treated with open chest surgical valve replacement on cardiopulmonary bypass. Heart Leaflet Technologies has developed an aortic valve prosthesis that can be delivered to the stenotic aortic valve through a catheter inserted in the femoral artery.

The purpose of this study is to confirm that the dimensions of the HLT valve are appropriate for patients with aortic valve stenosis. There is no animal model of aortic valve stenosis. Heart Leaflet Technologies has performed extensive device geometry and deployment testing on fixed cadaveric hearts with calcified cusps and aortic stenosis. HLT has also performed a number of preclinical animal experiments to verify deliverability and device function in vivo.

Inclusion Criteria:

1. Patients undergoing aortic valve replacement for aortic valve stenosis with a preoperative valve area < 0.9 cm2.
2. A preoperative echocardiogram where the aortic annulus diameter can be measured and is between 19 and 25 mm internal diameter.
3. Age 75 to 80 years

Exclusion Criteria:

1. Emergency valve surgery
2. Significant ascending aortic disease (atheroma, extensive calcification, dissection) as assessed by the operating surgeon
3. Ostial coronary obstruction > 25% diameter stenosis