Abstract
This study was designed to study the healing mechanism of vein prostheses. The morphological features of the inner capsules of prostheses implanted in dogs were examined by means of light and scanning electron microscopy.
Expanded polytetrafluoroethylene vascular prostheses were implanted into the superior vena cava of dogs. The animals were sacrificed at 4 hours, 24 hours, 2 days, 3 days, 4 days, one week, two weeks, 6 weeks, 8 weeks and 10 weeks after implantation and the pellicle preparation then underwent gross examination, as well as light and scanning electron microscopic studies of the inner surface.
At 24 hours after implantation, isolated neo-endothelial-like cells (spindle shaped) on fibrin mats were seen. Organization of thin thrombi was observed in localized regions adjacent to both suture lines and the fibrin mats were covered by neoendothelial cells at the proxymal anastomotic only one week after implantation. At two weeks after implantation, the organization of the inner capsule progressed more widely and there were neo-endothelial cells not only inwards from the ends but also in the central area. The spindle-like neo-endothelial cells were arranged along the line of blood flow. They then tended to become flatter and spread out. Numbers of isolated neo-endothelial cells were incorporated in the continuous sheets of new endothelium adjacent to the suture lines. By 10 weeks the entire inner surface of the graft was covered by neo-endothelial cells.
