Analytical approach on leaflet flutter on biological prosthetic heart valves

Abstract

Biological prosthetic valves are known for having good hemodynamics and resistance to clot formation, but they also have the disadvantage of possessing a short lifespan. An understudied effect is the fluttering of cusps, which is associated with calcification, hemolysis, and fatigue. The present study used a mathematical model of eigenvalues calculation to predict the critical speed of flutter onset in porcine and bovine pericardium valves, comparing the results with experiments on a test bench. Most results were below the speeds found experimentally, an outcome usually found in other flutter analytical theories. The analytical method demonstrated that pericardial valves have greater resistance to the onset of flutter than porcine valves, which agrees with experimental results. The sensitivity analysis showed that the internal diameter has a high impact on the critical speed, while thickness has greater importance when considering critical flow. The same analysis demonstrated that the higher thickness and elastic modulus values of pericardial valves explain why it has an increased resistance to cusps oscillation in comparison with porcine. The mathematical model in this paper is the first flutter analytical theory focused on heart valves. It can assist in new bioprosthesis projects that can be more resistant to oscillations and early fatigue failure.