. . "Preferred biocompatible materials are fluoropolymers, most preferably PTFE and expanded PTFE (TEFLON), fluorinated ethylene propylene, polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polyvinylchloride, polypropylene, polyethylene terephthalate, polyurethane, polyureas, fibrin, broad fluoride, silicone and other biocompatible materials." . . . .