A study on auto-saphenous vein graft (1)

Ultrastructual changes and localization of tissue plasminogen activator during the preparation of human saphenous vein graft were studied employing transmission and scanning electron microscope and histochemical fibrin slide technique of modified Todd's methood.Samples of great saphenous vein were excised from five patients who underwent stripping for varicose veins of mild degree. Preparation media for storage of vein graft included (1) heparinized normal saline at room temperature, (2) heparinized normal saline at 4°C, and (3) heparinized whole blood at room temperature. Veins were subjected to 30-, 60-, 90-, 120-, and 180-minutes storage in each medium at which times segments were removed for study.Apparent endothelial cell swelling and focal cellular disruptions were common after 60-minutes storage in normal saline at room temperature. These changes were minimal in whole blood and cold saline storage. After 120-minutes storage even in the cold saline, the most favorable preservative, cell swelling of endothelium, degenerative changes of endothelial mitochondria, disruption of basal lamina and accumulation of intercellular debris were observed frequently. Smooth muscle was minimally damaged in all the preservatives comparing with the endothelial changes.Scanning electron microscopic study revealed striking endothelial cell swelling, intimal ulceration and exposure of subendothelial connective tissue, especially in normal saline at room temperature after 60-minutes storage. Vessels preserved in heparinized whole blood showed platelet-fibrin net formation frequently after 120-minutes storage.Presence of fibrinolytic activity was demonstrated in all three layers of cold normal saline and whole blood stored specimens, however diminished activity was present in the intima of normal saline storage at room temperature after 60-minutes.From the results mentioned above, it was concluded that cold normal saline could be preferable for vein preservation under conditions studied in this investigation.