Fluid Dynamic Studies of a Porcine Aortic Valve in Preparation for Future Living Tissue Valve Studies

Open Access
Author:
Schmiech, Kathryn Victoria
Area of Honors:
Bioengineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Keefe B Manning, Thesis Supervisor
  • William O Hancock, Honors Advisor
  • Peter J Butler, Faculty Reader
Keywords:
  • aortic valve
  • fluid dynamics
  • porcine valve
  • particle image velocimetry
Abstract:
About 290,000 heart valve replacement surgeries are performed every year, and the demand for artificial heart valves is increasing 10-12% annually. Current artificial heart valves, mechanical and bioprosthetic, have been developed over the past 50 years but are still not sufficient. Complications often arise from artificial heart valves because of irregular fluid dynamics, leading to thromboembolism, platelet activation, hemolysis, calcification, and stenosis. The need for a better alternative has led to a tissue-engineered heart valve (TEHV). Ideally, the TEHV would mimic the biomechanics as well as grow and strengthen as a normal heart valve. With the development of this new valve comes the need to test the fluid dynamic properties of flow associated with the valve and compare it to current artificial valves. The properties of flow development through a valve are linked to complications associated with the valve. To test these properties, a mock circulatory loop is made integrating an acrylic valve testing chamber that houses the valve and mimics the aortic sinuses. A nontoxic blood analog that mimics the viscoelastic properties of blood is used in the loop. Particle image velocimetry is used to measure the flow downstream of the aortic valve. In this study, the flow about a native porcine valve is analyzed at 50, 75, and 100 beats per minute (bpm). The porcine valve flow patterns will be used as a comparison to the flow associated with a tissue-engineered valve to assess viability. Important characteristics to analyze in the flow fields include systolic jets, areas of recrculation and stagnation, and high velocity gradients. The results show a systolic jet developing during all three beat rates with areas of stagnation and recirculation outside the jet. These jets include some areas downstream that are skewed or separated. During diastole, the individual porcine leaflets successfully stay closed with no leakage.