A soft tissue implant device such as a catheter, heart valve, or plastic or reconstructive surgical material, to be at least partially embedded in an implantation site in soft organic tissue of a living organism includes a body defining a surface layer extending over the portion of the body contacting the organic tissue. The surface layer defines a three-dimensional pattern with an exterior surface defining a plurality of spaces and a plurality of solid surface portions. The spaces have a mean bridging distance ranging from greater than 1.0 micron to less than 4.0 microns and the solid surfaces portions have mean breadths ranging from 0.10 micron to 2.0 microns. The mean bridging distance is preferably greater than 1.4 microns and less than 1.9 microns. The exterior surface is substantially free of indentations having a bridging distance measuring in a range from between 10.0 microns and 1,000 microns.

A soft tissue implant device such as a catheter, heart valve, or plastic or reconstructive surgical material, to be at least partially embedded in an implantation site in soft organic tissue of a living organism includes a body defining a surface layer extending over the portion of the body contacting the organic tissue. The surface layer defines a three-dimensional pattern with an exterior surface defining a plurality of spaces and a plurality of solid surface portions. The spaces have a mean bridging distance ranging from greater than 1.0 micron to less than 4.0 microns and the solid surface portions have mean breadths ranging from 0.10 micron to 2.0 microns. The mean bridging distance is preferably greater than 1.4 microns and less than 1.9 microns. The exterior surface is substantially free of indentations having a bridging distance measuring in a range from between 10.0 microns and 1,000 microns.

A vascular prosthesis for implantation in a living mammalian body and a method for producing same are disclosed. The vascular prosthesis has a hydrophobic polymeric layer on its luminal surface defining a substantially non-thrombogenic flow surface. The polymeric material of the layer defining the flow surface exhibits a rate of platelet consumption of less than about 20.times.10.sup.8 platelets/cm.sup.2 .multidot.day.

The medical material contains heparinized collagen in which heparin has been bonded to protamine covalently fixed on collagen, and, owing to its excellent compatibility with living bodies, especially, its superb antithrombotic property, can be suitably used as a substituent material for tissues or organs which are brought into direct contact with blood, namely, as aritificial vessels, artificial valves and patching materials for cardiovascular organs, and the above medical material is also suitable as a membrane having anti-adhesion effects. The medical material is obtained by immersing and treating a natural or artificial material successively in an aqueous protamine solution, an aqueous glutaraldehyde solution and an aqueous heparin solution.

A method and apparatus for manufacturing a circulatory system non-pyrogenic vascular prosthesis comprising a multilaminar tubular member comprising an interior strata, a unitary medial strata and an exterior strata. The interior strata bears a pseudoneointima facilitating lumen surface and the exterior strata bears a stabilization promoter surface. The interior and exterior stratum being separated solely by said unitary medial strata which comprises an exclusionary boundary.