cell formation cannot be fully explained fibrin deposition on the wall of the graft can be assumed to be of vital importance for cell formation by the adoption of very minute fibers a large number of microgaps among the fibers are formed which allow cell and fibrin to enter more easily thus it appears that fibrin deposition is very uniform thin and consolidated when very minute fibers are used when such fibers are used for both inner and outer walls of the graft the adaptability of the graft to the surrounding tissues is promoted sometimes this quality is unnecessary for the outer wall of the graft when the structure of the graft made as described here is made multiple by the combined use of very minute fibers a and fibers of 1 0 denier or more b the grafts show better performahce in particular employment of the fibers b not only prevents deformation of the artificial vascular grafts but also enhances cell formation in preparing grafts according to the preseht invention such multiple structures are recommended as double weft structure double warp structure double warp and weft structure triple or greater warp and weft structure weft pile structure warp pile structure a structure produced by the application of these structures cut pile of these structures and fabrics produced by combining these structures these fabric structures are obtained by weaving these structures these fabric structures are obtained by weaving or knitting preferably tricotting to prevent ravelling of the graft the prefered fabric structure by tricotting are.