Abstract: A method of making a biocompatible hollow artifact with perforated walls made from a substrate of electro-conductive material whose surface is exposed to a biological environment, such as living animal tissue or blood, to impart to said material biocompatibility at the site of exposure, comprising:subjecting said exposed surface of the substrate to exposure to a plasma gas discharge in a plasma zone containing a plasma polymerizable monomeric gas to form a thin flexible coating on said substrate, said exposure being performed for a sufficient period of time and under relative movement between said plasma zone and said substrate, the volume of said plasma zone being capable of complete immersion of the substrate and being of such a magnitude in relation to the volume of the substrate as to enable the substrate to travel in or through the plasma zone under plasma polymerization without disturbing the plasma generation.