Leaflet Model of Aortic Stenosis to Relate Valve Narrowing to the Acoustic Spectrum

Aortic stenosis, a narrowing of the aortic valve, is one of the most common heart valve diseases. The severity of the stenosis is often classified by the abnormal sounds produced by the blood flow and recirculation through the aortic valve. In modeling the aortic valve, a quantitative study of the effect of the narrowing on the acoustic spectrum can be assessed. In the model setup, the flow of blood through the aortic valve is simulated with a system using water and a pulsatile pump. The sounds produced by these restrictions are measured with a contact microphone, mimicking the function of an electronic stethoscope. The sound signals are then decomposed into an energy spectrum that measures the energy content of the frequencies present. Different restrictions are created through 3D-printing flexible leaflets modeled after the semi-triangular tri-leaflet shape of an open aortic valve. Dynamic similarity between the model and actual human heart flow conditions allows comparisons to be made across flow conditions. This project aims to test the effect of leaflet thickness on the acoustic signal and identify characteristic frequencies that correlate with the geometry, with initial findings indicating that thicker leaflets lead to enhanced high frequency content in the signal.