Hydrodynamic function of polyurethane prosthetic heart valves: influences of Young's modulus and leaflet thickness

• Published in: Biomaterials 2002, Vol.23 (1), p.45-50
• Main Authors: Bernacca, Gillian M., O’Connor, Bernard, Williams, David F, Wheatley, David J.
• Format: Article
• Language: English
• Subjects: Heart Valve Prosthesis; Hydrodynamic function; Leaflet thickness; Modulus; Polyurethane; Polyurethanes
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/S0142-9612(01)00077-1

The development of flexible polyurethane heart valves has been hindered by material degradation in vivo. Low modulus polyurethane leaflets are regarded as desirable to achieve good hydrodynamic function. However, low modulus materials may suffer high strain accumulation, hence poor durability. Higher modulus materials may improve durability, but may have poor hydrodynamic function. This study examines the hydrodynamic behaviour of biostable polyurethane valves, varying Young's modulus from 5 to 63.6 MPa and mean leaflet thickness from 48–238 μm. Parameters studied included mean pressure gradient, energy losses and regurgitation over 5 equivalent cardiac outputs (3.6, 4.9, 6.4, 8.0 and 9.6 l min −1). At low cardiac output, modulus was not significantly correlated with any parameter of valve opening. At 9.6 l min −1, modulus significantly influenced mean pressure gradient ( p=0.033). Mean leaflet thickness significantly correlated with mean pressure gradient and energy losses during forward flow at all cardiac outputs ( p