A Method for Determination of Pressure Drop in Caged-Ball and Caged-Disc Prosthetic Cardiac Valves

Abstract

This paper describes a simple theoretical and experimental method to determine the pressure drop across mitral caged-ball and caged-disc prosthetic heart valves under steady state flow conditions. The overall pressure drop across any mechanical artificial heart valve is affected not only by its orifice, but also by the poppet design and the entire superstructure of the valve. In this study, the total pressure drop across the prosthesis is considered to be equal to the sum of the pressure drops due to the valve occluder and the orifice. These two pressure drops are analysed separately and then superimposed to obtain the total pressure drop. Experimental total pressure drops at different volume flow rates were obtained using an appropriate pressure transducer. The valves were installed inside a test chamber which enables pressure drop measurements under steady state flow conditions using a blood analog fluid. The theoretical and experimental results of pressure drop are in good agreement, particularly in the physiological range of interest, for both valve types. Also, it was found, as anticipated, that the pressure drop through the tested prosthetic heart valves is mainly due to the orifice flow.