Sponsor decision to stop enrollment.

To evaluate the safety and performance of the HLT System in patients with symptomatic heart disease due to severe aortic stenosis who are judged by the Heart Team to be at Intermediate or High Risk for aortic valve replacement surgery.

Prospective, non-randomized, single arm, multi-center CE Mark trial.

Inclusion Criteria:

• Echocardiographic or hemodynamic based evidence of severe aortic stenosis with one of the following:

  1. Aortic valve area ≤ 1.0 cm^2 or 0.6 cm^2/m^2
  2. Mean aortic valve gradient ≥ 40 mmHg
  3. Peak aortic valve velocity ≥ 4 m/sec

• Symptoms due to severe aortic stenosis resulting in one of the following:

  1. NYHA Functional Classification of II or greater
  2. Presence of angina
  3. Presence of syncope

• Documented aortic valve annular size of ≥ 24 and ≤ 26 mm (associated perimeter range is 76-81mm or associated area range of 453-530 mm2) by the MSCT Core Lab assessment of pre-procedure imaging.

• Patient is considered intermediate or high risk to undergo surgical aortic valve replacement with one of the following:

  1. Intermediate Surgical Risk: STS-PROM score of ≥ 3% to 8%
  2. High Surgical Risk: STS-PROM score of ≥ 8%
  3. Documented heart team agreement of risk for surgical aortic valve replacement (SAVR) due to other factors not captured by risk-scores (i.e. frailty or comorbidities)

• Geographically available, willing to comply with follow up and able to provide written informed consent

Exclusion Criteria:

• Patients with a coronary height of <10mm, or otherwise determined to be at high risk for coronary obstruction
• Patients with low flow/low gradient aortic stenosis
• Patients with significant annular or LVOT calcification that could compromise procedural success
• Pre-existing prosthetic heart valve in any position, or prosthetic ring
• Severe aortic, mitral or tricuspid valve regurgitation
• Untreated clinically significant coronary artery disease requiring revascularization
• Unfavorable peripheral vascular anatomy or disease (e.g. severe obstructive calcification or severe tortuosity) that would preclude passage of 18 Fr catheters from the femoral arterial access to the aorta as evidenced by peripheral MSCT
• Need for emergent surgery or intervention other than the investigational procedure