Endothelial cell seeding of a new PTFE vascular prosthesis

Previous attempts to line polytetrafluoroethylene (PTFE) prostheses with enzymatically derived endothelial cells have not been as successful as similar work with Dacron grafts because of the failure of such prostheses to develop a satisfactory subendothelium. This article reports our experience with a new, highly porous, unreinforced PTFE prosthesis that appears to circumvent this problem. Segments (4 mm I.D., 10 cm in length) of this new graft were implanted in 41 mongrel dogs as carotid interposition grafts. One graft in each dog was seeded with the dog's own endothelial cells, whereas the contralateral graft was treated in an identical fashion except for the inclusion of endothelium. After a mean period of 7 weeks of implantation, the grafts were harvested, their patencies were noted, the thrombus-free area of their luminal surface was calculated with computerized quantitative planimetry, and graft segments were submitted for scanning and transmission electron microscopy. In seven dogs the luminal surface was scraped from each graft and measured quantitatively. Although seeded grafts failed to show a statistically significant increase in patency during the short course of this experiment, a trend in that direction was quite striking. Furthermore, seeded grafts had a significant increase in thrombus-free area on their luminal surface as well as a significant reduction in the volume of luminal thrombus. Histologically, seeded grafts developed a substantial 75 to 100 microns cellular subendothelium beneath a confluent endothelial lining. No endothelial lining was noted in control grafts. We believe that the superior handling characteristics of this new prosthesis and its ability to develop a substantial subendothelium with a confluent endothelial lining suggest potential future applications and warrant further investigation.