One aspect of the present invention provides implantable medical devices that comprise: (a) a device body; and (b) a surface layer attached to at least a portion of the device body, the surface layer comprising: (1) a surface layer body that defines an internal surface attached to the device body, and an external surface; and (2) a multiplicity of blood vessels disposed within the surface layer body, the blood vessels opening onto the external face of the surface layer body. The present invention also provides synthetic biocompatible materials, methods for making synthetic biocompatible materials, and methods for making implantable medical devices.