The purpose of this pilot study is to obtain both near valve and downstream flow characteristics, using 3D transthoracic echocardiography and 4D flow MRI respectively, in an existing patient population at Northwestern Memorial Hospital, to determine the hinge washout characteristics and downstream flow patterns of the On-X valve and compared to competing designs.

Prospective, concurrent 4D flow Magnetic Resonance Imaging (MRI) and echocardiography of On-X and St Jude Medical (SJM) Masters HP or Carbomedics Carbo-seal or Carbo-seal Valsalva aortic valve replacement (AVR) patients will be performed. Echocardiography analysis will include: valve function (opening angle), pressure gradients, and degree of valve washout. MRI analysis will focus on downstream flow patterns (helicity and vorticity), energy loss, pressure recovery, and measurement of wall shear stress in the anastomosis regions.

Inclusion Criteria:

• Male and female subjects 18-89 years of age
• Patients with aortic valve disease who within the last five years underwent AVR using the On-X aortic valve, SJM Masters HP, or Carbomedics aortic valves.

Exclusion Criteria:

• Patients contraindicated against MRI
• Patients with pacemakers, cochlear (in the ear) implants, or aneurysm clips or patients who have worked with metal
• Patients unwilling or unable to give written informed consent
• Pregnant women
• Prisoners
• Patients with an Effective Orifice Area index (EOAi) <0.85 cm2/m2

Patients with aortic valve disease who within the last five years underwent AVR using the On-X aortic valve, SJM Masters HP, or Carbomedics aortic valves.