Porous polyurethane vascular prostheses with variable compliances

Abstract

A new technique for the preparation of porous vascular prostheses was investigated. Polyurethane solution (5 to 15 wt%) was injected into a mold. After freezing at low temperature (0°C–196°C), solvents were dissolved out with water at 0°C to form porous tubes. The average pore size (several microns to 70 μm), pore occupation (10% to 51%), and compliance (3% to 35%) were easily changed by changing polyurethane concentration, freezing temperature, and freezing methods. Compliances could be decreased gradually by heat treatment. This technique can give a proper pore size (30‐60 μm) for tissue ingrowth, and a suitable compliance for matching with arteries and veins. This method might give a desired compliant graft for artificial implantation with the presently valid medical polymers. © 1992 John Wiley & Sons, Inc.