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Cells and Materials

Abstract

e-PTFE vascular grafts (Gore, internal diameter 1.5 mm, pore size 30 μm) were luminally treated by ionbeam etching followed by oxygen glow-discharge, to obtain a superhydrophobic luminal surface. Water contact angles of thus modified sheet material were 140-150°, which is significantly higher than on non-treated sheet PTFE (109°). These modified vascular grafts were implanted in the rabbit carotid artery, using an end to end anastomotic technique. After two hours, the grafts were still patent and the wounds were closed. One week after the implantation, the prostheses were still patent. Subsequently, the grafts were harvested and prepared for light microscopy, transmission electron microscopy, and scanning electron microscopy. The lumen of the modified e-PTFE prostheses was covered with a very thin fibrous- proteinaceous layer, in which platelets were entrapped. An occasional monocyte was attached to the surface of the adsorbed layer. The platelets formed a mixed population: in particular the platelets at the luminal surface seemed quite vital, others were partly activated and some were dead. Nevertheless, platelets did not induce the regular thrombotic cascade. The adsorbed luminal layer was never thicker than approximately 50 μm. At the anastomotic sides, some endothelial overgrowth could be observed. In conclusion, we can state that superhydrophobic modification of small caliber e-PTFE vascular grafts results in a patent graft, even after 1 week of implantation. Apparently, a low thrombogenic/passified surface has been created on which only a very thin fibrous-proteinaceous layer is deposited.

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