A hybrid (hydro-numerical) circulatory model: Investigations of mechanical aortic valves and a numerical valve model

Abstract

In most cases of diseased heart valves, they can be repaired or replaced with biological or mechanical prostheses. Biological prostheses seem to be safer than mechanical ones and are applied with good clinical outcomes. Their disadvantage, when compared with mechanical valves, is durability. In the development and application of mechanical and biological heart valves, a significant role can be played by a Hybrid (Hydro-Numerical) Circulatory Model. The aim of this paper is to demonstrate the opportunities created by the hybrid model for investigations of mechanical heart valves and their computer models under conditions similar to those of the circulatory system. A diode-resistor numerical valve model and three different design mechanical aortic valves were tested. To perform their investigations, computer applications were developed under RT LabView to be run on a PC. Static and dynamic characteristics of the valves were measured and registered - pressure in the numerical time-varying elastance left ventricle (pLV), in the aorta (pas) and flow (f), proving, among other factors, that 1) time delay of pas with respect to pLV is mainly related to the valve's opening time, and 2) the valves of substantially different designs tested under identical hydrodynamic conditions reveal nearly the same dynamic performance.