Small-diameter polyurethane-polydimethylsiloxane vascular prostheses made by a spraying, phase-inversion process

A highly porous, distensible, gel-like tubular membrane suitable for a small diameter arterial prosthesis was fabricated by combining techniques for spraying and phase-inversion of thermodynamically unstable solutions of a biocompatible polyurethane (PU)-polydimethylsiloxane (PDMS) blend (CardiothaneTH51) over a sliding and rotating mandrel. The cylindrical membrane was characterizedin vitro for mechanical, morphological and permeability properties, and evaluatedin vivo as a 1.5 mm internal diameter prosthesis for the replacement of the rat abdominal aorta. A mature, stable luminal interface, a thin internal capsule without anastomotic hyperplasia, and the deposition of collagen within the voids of the polymer mesh were observed after 8 weeks of implantation.