Effect of bending rigidity in a dynamic model of a polyurethane prosthetic mitral valve.

We investigate the behaviour of a dynamic fluid-structure interaction model of a chorded polyurethane mitral valve prosthesis, focusing on the effects on valve dynamics of including descriptions of the bending stiffnesses of the valve leaflets and artificial chordae tendineae. Each of the chordae is attached at one end to the valve annulus and at the other to one of two chordal attachment points. These attachment points correspond to the positions where the chords of the real prosthesis would attach to the left-ventricular wall, although in the present study, these attachment points are kept fixed in space to facilitate comparison between our simulations and earlier results obtained from an experimental test rig.

Modelling chorded prosthetic mitral valves using the immersed boundary method.

The Immersed Boundary (IB) Method is an efficient method of modelling fluid structure interactions. However, it has two main limitations: ease of use and ability to model static loading. In this paper, the method is developed, so that it can efficiently and easily model any multileaflet elastic structure.

Our inability to predict thromboembolic events after prosthetic valve surgery.

Background And Aim Of The Study: Thromboembolic and bleeding complications detract from outcome for patients with prosthetic heart valves. The study aim was to investigate whether measurement of coagulation activation markers and transcranial Doppler ultrasound microembolic signals (MES) could identify patients at subsequent higher risk of thromboembolism or bleeding events.

Methods: A total of 526 patients (mean age 66 years; 266 males, 260 females) who underwent elective valve replacement surgery was enrolled between April 1999 and October 2002.

Dynamic modelling of prosthetic chorded mitral valves using the immersed boundary method.

Current artificial heart valves either have limited lifespan or require the recipient to be on permanent anticoagulation therapy. In this paper, effort is made to assess a newly developed bileaflet valve prosthesis made of synthetic flexible leaflet materials, whose geometry and material properties are based on those of the native mitral valve, with a view to providing superior options for mitral valve replacement. Computational analysis is employed to evaluate the geometric and material design of the valve, by investigation of its mechanical behaviour and unsteady flow characteristics.

Comparison of prosthetic valve hydrodynamic function: objective testing using statistical multilevel modeling.

Background And Aim Of The Study: The performance of novel prosthetic heart valves is assessed using in-vitro hydrodynamic function tests. The study aim was to examine the problem of objective discrimination of hydrodynamic performance to determine significant differences between valve designs, and illustrate proposed methodology using data collected from five different polyurethane tri-leaflet valve designs.

Methods: Two engineering designs were manufactured with leaflets of the same polyurethane (GE, LE); design L was manufactured using three further leaflet materials of differing material modulus (LL, L4, L5).