ABSTRACT
The 3M Precise Microvascular Anastomotic System has had an experimental long-term
testing for the first time in polytetrafluoroethylene (PTFE) 1-mm diameter arterial
grafts. The grafts were placed in the infrarenal aorta of 48 rats. At different time
intervals (2 weeks, 16 weeks and 1 year), each section containing a graft and its
pair of anastomotic devices was removed and processed for light and scanning electron
microscopy, with the aid of a newly-designed device. Eighty-three percent of the mechanically
anastomosed grafts were found to be patent. Only 14.8 percent of the grafts harvested
at 16 weeks or 1 year showed neo-endothelial lining on the inner surface of the graft.
A constant finding of this study was the marked atrophy of the aortic media within
the devices, that was progressively evident from 2 weeks to 1 year. A network of capillaries
within the graft walls was present at 16 weeks. In one case, a large capillary was
found to traverse the graft wall and to reach the luminal surface, suggesting that
transmural capillaries may contribute to the formation of neo-intima in 1-mm PTFE
grafts.
