Artificial vascular and patch grafts

A flexible artificial fabric prosthesis for prolonged or permanent implantation in a living body, comprising a fiber substrate array of organopolymeric fibers having a tensile modulus of elasticity of at least about 2.times.10.sup.6 psi, a tensile strength of at least about 20,000 psi and a fiber diameter of less than about 25 microns, said fiber substrate being adapted to sustain the functional stresses encountered by the implanted prosthesis and to provide a desired high degree of prosthesis flexibility without straining more than about 5 percent, and

• a dense, adherent isotropic carbon coating on the fibers of at least one side of said fiber substrate array having a BAF of about 1.3 or less, a density in the range of from about 1.6 gm/cm.sup.3 to about 2.0 gm/cm.sup.3, a thickness of less than about 7000 Angstroms, and a tensile fracture strain of at least about 5 percent, said fibers being individually provided with said adherent carbon coating and not substantially bonded together thereby, whereby said coated fibers are free to bend to a bending radius of about 0.025 cm or less and to glide over each other in the flexure of the prosthesis without substantial breaking of said carbon coating.