Summary
Microvascular fibrous polyurethane prostheses (inner diameter 1.5 mm, length 10cm) were implanted in the abdominal aorta of rats. The prostheses were fixed in a loop. All rats (n = 37) were reoperated 6 weeks after implantation to verify the patency of the prostheses. Eight prostheses were obliterated from various causes. The remaining 29 prostheses were found to be patent 3 months after implantation, which gives a patency rate of 79%. Six weeks and 3 months after implantation 7 and 4 rats, respectively, with patent prostheses were sacrificed.
The remaining 18 rats of this study are still alive, more than 4 months after implantation, and will be included in longterm observation studies. The prostheses were examined using both light and scanning electron microscopy, The patent prostheses exhibited macroscopically a clear and transparent inner surface. No obliterative processes could be found either macroscopically or microscopically.
Neo-intima ingrowth had advanced ± 10 mm into the prostheses over the anastomotic line from both ends 3 months after implantation, and was continued by a single endothelium layer for several centimeters.
An acellular, stable fibrin film was found inbetween the cellular lining. The neo-intima was anchored at the prosthesis by cellular protrusions extending between the polyurethane fibers.
Though 10 cm long prostheses were implanted under unfavorable hemodynamic conditions, a patency rate of 79% was achieved, both 6 weeks and 3 months after implantation. This patency rate could have been higher if evident technical failures had been avoided.
In conclusion: The implantation of a 10cm-long fibrous microvascular polyurethane prosthesis in the rat aorta is feasible, and high patency rates can be obtained.
Key words
Microvascular prosthesis - Neo-intima - Patency rate - Polyurethane prosthesis - Rat
