Computer modelling of bioprosthetic heart valves.

The underlying assumptions and principles of a computer-based model for tissue heart valves are described. The model is used to relate observations of leaflet morphology to the requirements of proper valve function. Stress is the fundamental mechanical factor that limits the longevity of bioprosthetic heart valves--the higher the stress levels in the leaflets, the shorter will be the time over which the leaflets can maintain satisfactory structural integrity. Direct measurement of stress is impractical with real heart valves, but the calculation of stress and the study of its interdependence on other key parameters of tissue valve design is a good alternative. The methodology of computer modelling of heart valves is discussed and the technique is illustrated with some examples. Models of pericardial valves, the aortic allograft and porcine bioprostheses are compared.