Thromboresistance of stellite 21: The role of an adventitious waxy contaminant

Thromboresistance of the alloy most often used in artificial heart valves depends upon a hitherto unrecognized erosion resistant hydrocarbon coating. Contact angle measurements show the actual surface to be dominated by closely packed methyl groups as occur with adlineated aliphatic chains. The likely source for this layer is a tallow‐based compound from which adventitious components become tightly bound at the metal/air interface during final polishing. Here, as in other systems, the exposure of CH₃ terminal groups correlates with significant blood compatibility.