Synthetic sapphire as an artificial heart valve occluder-promise and problems

Abstract

A tilting disc artificial heart value using a synthetic sapphire disc and TiN coated Haynes alloy cage was developed. Sapphire proved to have excellent biocompatibility, and the valve completed the accelerated durability test as per international protocol. However, in animal evaluation, the disc fractured in 5 out of 14 implants. Failure analysis of the discs was carried out by changing the assembly procedure, studying the crystalline orientation and by indentation. High flow and high pressure accelerated testing was conducted to induce fracture before implantation. It is concluded that there is a need to understand fracture mechanics and to able to eliminate defective components in critical ceramic components.