In this study an epoxy-fixed porcine pericardial patch with or without ionically bound heparin was evaluated in a canine model as an alternative to the glutaraldehyde-fixed biological patch for clinical applications. To evaluate the effectiveness of this epoxy-fixed patch, a composite membrane composed of: an epoxy-fixed porcine patch with ionically bound heparin; a glutaraldehyde-fixed porcine patch with ionically bound heparin; an ePTFE polymeric patch; a polyester polymeric patch; an epoxy-fixed porcine patch without ionically bound heparin; and a glutaraldehyde-fixed porcine patch without ionically bound heparin was made. This membrane was assessed orthopically in a canine model. The early results (1-4 weeks post implant) revealed that the biological patches with ionically bound heparin had the mildest tissue reactions (inflammatory reaction, fibrosis, and adhesion) among all the test samples. However, by 12 weeks postoperatively: all the test samples had mild to severe tissue reactions. The order of tissue reactions with increasing severity was: the biological patches with ionically bound heparin, the biological patches without ionically bound heparin, and the polymeric patches The results suggest that heparin may be used to reduce adhesion. Additionally the epoxy-fixed tissue caused a relatively lower degree of inflammatory reaction than the glutaraldehyde-fixed tissue.
