Eduardo Guy Perpetuo Bock*, Rosa Correa Leoncio de Sa, Tarcisio Fernandes Leao, Evandro Drigo da Silva, Vladimir Jesus Trava Airoldi and Aron Jose Pazin de Andrade
Ventricular Assist Devices (VAD) are blood pumps that can stabilize the hemodynamics of patients with severe heart failure. The VAD indication is for therapeutically assist before, during and/or after transplant, recovery and destination therapic. Our group propose a centrifugal blood pump as VAD that consists of a rotor magnetically coupled, suspended by pivot bearings. The pivot is mainly a ceramic axis with rotational movement and the bearing is a polished surface made mainly with polymers. As a whole system, a VAD should be made of long-life biomaterials to avoid degradation or deformation during application lifetime. Surface modification techniques have been widely studied and implemented to improve properties such as biocompatibility and durability of applicable materials. The chemical vapour deposition technique allows substrates having melting point higher than 300°C to be coated, encapsulated, with a Diamond Like Carbon (DLC) film. The amorphous carbon film coated material provides the surface properties such as hardness and improved self-lubricating and biocompatibility for specific application. The objective is to study VAD pivot bearings made PEEK and medical grade titanium with DLC coating. Regarding VAD continuous operation and its relation with the patient life support, the system must have a high level of reliability. In order to evaluate and compare the performance, two other pivots were made in titanium c.p. and alumina ceramic. The bearing was made of PEEK for each pivot. Then, there was the physical characterization of each component by electron microscopy and volume control, before and after in vitro tests of durability. The tests simulated the VAD friction and wearing. The results showed less deformation by abrasive wear and promising alternative to use DLC in VAD pivot bearings.
