[The 4 mm plasma-tetrafluoroethylene prosthesis as a coronary vessel replacement in the animal experiment]

For coronary artery revascularisation the availibility of a prosthesis may be useful, which in case of insufficient or inadequate veins may be used as a biocompatible substitute. The new 4 mm Plasma TFE prosthesis consisting of a woven fiber of polyethylenteraphtalate (PET) coated with an ultrathin layer of Tetrafluoroethylene (TFE) has shown to be highly non thrombogenic in vitro and was therefore regarded as being promising. In an experimental study 10 beagle dogs underwent aortocoronary bypass grafting in order to evaluate the in vivo behavior of the prosthesis. In group 15 dogs received a Plasma TFE prosthesis of 7 cm length. To overcome the problems of inadequate caliber at the distal side of the anastomosis another 5 dogs in group II received a composite sequential graft composed of a 4 cm proximal Plasma TFE prosthesis and a 3 cm distal autologous saphenous vein. Treatment with antiplatelet drugs (Aspirin) was started during the operation and continued by daily doses of 500 mg p. os. Control-angiography 1 week after the operation demonstrated patency of 1 out of 5 grafts in group I and 4 out of 5 grafts in group II. Half a year later the only graft from group I was still patent, whereas in group II all grafts had thrombosed. Histological examinations showed the graft coated with a layer of 50-250 microns fibrous tissue mear the aortic anastomosis, while more distally the prosthesis was completely occluded. In conclusion the 4 mm Plasma TFE prosthesis though promising from in vitro experiments has proven to be not suitable as a substitute for aortocoronary artery bypass grafting in the dog.(ABSTRACT TRUNCATED AT 250 WORDS)