Wear tests on polypropylene for use in prosthetic heart valves

A medical grade of polypropylene, as used in the Abrams-Lucas prosthetic mitral valve, was tested in a crossed-cylinder wear machine under conditions which reproduce those in the heart. The results show an initial dormant period of running in, followed by a steady wear rate of 2.71 × 10⁻⁵mg/m. This figure is used to give an estimate of valve life which agrees well with clinical data and confirms that the method is suitable for future use as a valve design aid without the need to resort to protracted testing of completed valves