Microsurgical application of freeze-dried venous allografts.

Freeze-dried venous interposition allografts with an internal diameter of 1.0 mm and a length of 1.0 cm were placed into the femoral arteries of 17 Sprague-Dawley albino male rats in order to investigate patency and host tissue response. The immediate patency rate was 88%. The epigastric island flap was monitored as a sign of patency in the early postoperative period (defined as 1 to 3 days). Twelve of the 17 subjects were observed for 2 months, at which point 66% (8/12) remained patent. There were two aneurysmal dilatations. Histopathological studies and transmission electron microscopy demonstrated that freeze-dried veins undergo complete remodeling in vivo by a normal reparative process and that they do not induce a cellular immune response in the host.