Morphological changes in the saphenous vein after dilatation with silastic tubes. An experimental study

In an attempt to make veins more suitable for bypass grafting, an experimental model in dogs was developed. The saphenous vein on the hind limbs was cannulated with a silastic tube, a ligature was placed proximally and distally, and the tube was left in situ for 1 to 9 weeks. Morphological studies including electron microscopy revealed "arterialization" of the veins with fibromuscular hyperplasia, increased deposition of collagen and preserved vasa vasorum. The endothelium was replaced by irregular cells, probably altered fibroblasts coated by an amorphous material. It is suggested that the "arterialized" veins may become more suitable for bypass grafting. But the luminal surface may be thombogenic and thus the usefulness of the graft may be diminished by thrombosis.