Staging arteriovenous fistula loops for lengthening of free-flap pedicles

The authors investigated the optimal period of maturation following the cre ation of arteriovenous (AV) loops using polyterafluoroethylene (PTFE) in a white rat model, which were subsequently used to support free-tissue transf er. The AV loops in Group 1 (n = 17) were allowed to mature for 3 days prio r to creation of the flap, while those from Group 2 (n = 14) were allowed t o mature for 5 days. Results were compared to those from a previous study i n which the authors reported an 80 percent initial patency rate (n = 30) an d a 67 percent viability rate, based on 12 patent loops after 7 days. In th e present study, patency rates were 59 percent for the 3-day group and 79 p ercent for the 5-day group; viability rates were 50 and 64 percent, respect ively. Considering both patent and nonpatent loops, the overall viability r ates were 29 and 50 percent, respectively. Maturation periods longer than 7 days for AV loops constructed from PTFE micrografts were determined to be preferable for subsequent free-tissue transfer.