A new cardiac wall substitute with high affinity for fibroblasts that can induce an endothelial cell lining

A new cardiac wall substitute (PC graft) was developed using equine pericardium cross-linked with a polyepoxy compound. Compared with glutaraldehyde cross-linked pericardium (GA graft), the PC graft showed an approximately 10 times higher affinity for fibroblasts as measured by our in vitro cell migration and proliferation test. Six PC grafts (5 x 3 cm) were implanted into the right ventricular-pulmonary outflow tract position as a cardiac wall patch. Three GA grafts were used as controls. The PC grafts showed excellent handling during surgery because of their softness and elasticity. These grafts were explanted at 2 and 7-8 weeks after implantation. All PC grafts showed a white and glistening surface without any thrombus formation except in one case where thrombus deposition was observed in the center of the graft. In the GA grafts, thrombus adhered to the luminal surface. Light microscopic observation showed that the PC graft surface was covered with a connective tissue layer and significant fibroblast infiltration. Approximately 60% of the area infiltrated by these fibroblasts was endothelialized, whereas in the GA graft, endothelialization was limited to within 2-5 mm of the suture line. Other areas were covered with a thrombus layer without any endothelial cells or fibroblast infiltration. PC cross-linking can maintain the biologic and mechanical properties of the original materials. The PC graft offered excellent affinity for fibroblast migration and proliferation, which induced an endothelial cell lining on the surface. The results of this experiment indicated that the PC graft, which obtained the natural antithrombogenic property, was superior to a GA graft in terms of safety as well as mechanical, physiologic, and biologic properties as a cardiac wall substitute.