Optimal preparation techniques for human saphenous vein grafts.

Endothelial damage during preparation of saphenous vein grafts is an important cause of early and late graft failure. To determine optimal preparation techniques for human saphenous veins (SVs), we made a scanning electron microscopic comparison of the effects of handling techniques, immersion media, and distention pressures on human SV morphology. Segments of SVs from 30 patients were divided into seven groups of five veins each. The effects of both blood and saline solution immersion at 4 degrees and 28 degrees C, 100 and 300 mm Hg distention pressures, and trauma from surgical instrumentation were examined. All groups of veins were fixed by perfusion with glutaraldehyde at 100 mm Hg to simulate arterial pressure and were examined with a scanning electron microscope. SVs immersed in warm saline solution showed massive endothelial cell loss, whereas SVs immersed in warm blood showed only moderate endothelial damage. Cold blood and saline immersion fully preserved endothelium; however, cold saline immersion produced mural edema. Distention to 300 mm Hg with saline solution produced severe endothelial damage and edema, an effect lessened by blood distention. Vascular clamping destroyed endothelium and fractured the intima and media. Marked luminal stenoses were caused by four of seven side branch ties that appeared normal externally. We conclude that human SVs are preserved best by a "no touch" harvesting technique in which manipulation is minimized, side branch ties are placed away from the SV wall, veins are immersed in cold blood, and distention above 100 mm Hg is avoided.