Fluid Mechanical Analysis of a Polymeric Thin Trileaflet Heart Valve

Open Access
Author:
Frank, Dylan Louis
Area of Honors:
Bioengineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Keefe B Manning, Thesis Supervisor
  • William O Hancock, Honors Advisor
  • Steven Deutsch, Faculty Reader
Keywords:
  • polymer trileaflet heart valve
  • Abiomed
  • fluid mechanics
Abstract:
Millions of people are affected by valvular heart disease, with the need for roughly 250,000 valve replacements each year. One of the leading contributors of this disease is valvular insufficiency, particularly of the aortic valve. A possible solution to this is a polymeric trileaflet heart valve. Abiomed© has two different types of polymeric trileaflet valves: a twisting and normal valve. Previous studies have shown that the twisting valve performs better hemodynamically, and was thus chosen to study further. In this experiment, we consider the effect of thinning the leaflets on the Abiomed Angioflex® twisting trileaflet valve. In order to help characterize the operation of this valve in the aortic position, a study of the flow through the valve and in the aortic sinuses is conducted. To do this, the valve is placed in an acrylic model mimicking the Sinuses of Valsalva and run in a mock circulatory loop. Using a 40% hematocrit viscoelastic blood analog under physiological conditions (72 bpm, 120/80 mmHg, 3.5 L/min), two-dimensional particle image velocimetry is performed at 100 ms intervals in diastole and at 25 ms intervals in systole over the cardiac cycle to acquire the flow. Analysis reveals that the thin polymer valve produces a wider systolic jet than the flow associated with the thick polymer valve, which results in a lower peak velocity and a flatter velocity gradient. Further analysis shows that the thin leaflet protrudes deeper into the sinus when compared to the thick leaflet. This produces more flow within the sinus than the thick leaflet valve, which in turn helps to feed the coronary ostia located within.