In an experimental investigation the replacement of arterial microvessels with microporous
expanded polytetrafluoroethylene was studied. The infrarenal segment of the rat aorta
was used as the scientific model. The inside diameter of the micrograft was 1 mm.
Using microvascular techniques a total of 18 prostheses were inserted. The animals
were harvested at time intervals from 3 days up to 3 months. Patency was determined
by angiography and at autopsy. The aorta implant junction, the characteristics of
the neointima development and the differentiation of the interstitial cells were studied
by scanning electron microscopy. Fourteen of the implanted micrografts remained patent
at the time of sacrifice, yielding an early patency rate of 77,7 %. As shown by scanning
electron microscopy, the development of the neointima took place in 2 stages. The
initial fibrin/platelet layer was reduced after one month and replaced by a definite
neointima with mononuclear cells, connected with interstitial cells. Investigation
of the aortaimplant junction showed the prosthesis functionally embedded in the structure
of the aorta. Expanded polytetrafluoroethylene as a prosthetic material for microvascular
prostheses was easy to handle and emerged compatible with other tissues. It can be
used as a substitute for bridging arterial microvascular defects.
Microsurgery - Expanded polytetrafluoroethylene - Scanning electron microscopy
