Fluid-dynamic effect of pannus formation around the prosthetic heart valve: in vitro demonstration using a heart-mimic pulsatile pump and particle image velocimetry

The abnormal growth of tissue, called pannus, is frequently found in patients who have an implanted prosthetic heart valve. Its growth is related to the valve dysfunction and disturbed blood flow in the aorta. We performed in vitro experiments to demonstrate the effects of pannus formation on hemodynamics and valvular function. The results showed that the opening angle of the heart valve changes depending on the size and shape of the pannus. The circular pannus decreased the maximum opening angle of the heart valve. Although the opening motion of the valve was not affected by the semi-circular pannus, one of the valve leaflets obstructed by the semi-circular pannus had a closing dysfunction during the cardiac cycle, implying aortic insufficiency and regurgitation in the patients with this type of pannus formation. The experimentally measured pressure gradient and velocity-based transvalvular pressure gradient estimation increased with the growth of the pannus, although a discrepancy between the two estimations was observed.