Integrity of vein grafts as a function of initial intimal and medial preservation

Abstract

An "optimal" technique of vein graft preparation with papaverine and tissue culture was compared with an "injury" technique with 37 degrees C saline storage for 1 hr. Paired interposition cephalic vein grafts were placed in the femoral arteries of dogs. Specimens were taken at the time of implantation, at 3 and 24 hr, and at 7 and 30 days for light, scanning, and transmission electron microscopy. Veins obtained by the injury method showed extensive initial disruption of the endothelium and platelet and white cell adhesion at 3 and 24 hr. At 7 days the endothelium was restored, but there was marked inflammation and neovascularization of the media. At 30 days this had resolved; however, the smooth muscle cells appeared modulated (increase in relative numbers of metabolic organelles with contractile apparatus disassembly). Extracellular matrix was substantially increased, with abundant amorphous ground substance. In contrast, veins obtained by the optimal method had intact endothelium both at implantation and thereafter. Adhesion of white cells and platelets to the endothelium did not occur. The media remained compact without inflammation and without modulation of the smooth muscle cells. We conclude that vein grafts prepared by the optimal technique do not develop early or late evidence of endothelial or medial injury. This should result in a nonthrombogenic graft immediately after surgery and diminished late intimal/medial hyperplasia.