Project Thrombus Surface Properties of Materials for Prosthetic Implants

摘要

Data was gathered to allow some cautious generalizations to be drawn about the change in plastic vena cava rings' surface properties which occurs during implantation. The nature of the change should correlate with the thromboresistance of the various materials. The initial generalizations are these: During implantation, all materials rapidly adsorb a tenaciously adherent coating of protein. On most materials, this adsorbed protein layer substantially changes the critical surface tension, to higher values for initially low-energy surfaces and to lower values for initially high-energy surfaces. Materials polymerized with the aid of surface-active agents or heparinized with the aid of surface-active coupling compounds (e.g. TDMAC) will leach these surfactants into the blood and thereby dramatically modify the interfacial properties in the vicinity of the implant. These materials are also prone to imbide lipids. Also investigated were the surface properties of Stellite plates and rings to better define the role of the adventitious 'tallow-polish' contaminant in determining the thromboresistance of the Stellite as used in prosthetic devices. Studies with ethylene-oxide-sterilized polymers have shown that the surface properties of some materials are detrimentally changed by gas sterilization, while other materials are substantially unchanged. Firm conclusions are not yet available. (Author)