Human Saphenous Vein and Coronary Bypass Surgery: Scanning Electron Microscopy of Conventional and ‘No-Touch’ Vein Grafts

Conventional coronary artery bypass grafting (CABG) is the most common cardiac surgical procedure for treating coronary artery disease (CAD). The greater saphenous vein (SV) is the most commonly used conduit material for aortocoronary grafting. During conventional harvesting of the SV graft for CABG the surrounding tissue is removed and the vein distended before implantation takes place. This results in mechanical trauma to the vascular tissue. A no-touch preparation technique for CABG has been developed where the SV graft is harvested with its surrounding tissue preserved. This functions as a protective cushion that protects against vasospasm and reduces mechanical stress. Collectively, various post-implantation studies of patients showed a significant improvement in the patency of no-touch grafts compared to conventionally harvested grafts. The aim of the present study was to examine the effects of the two harvesting techniques of SV for CABG. SV segments were prepared and their morphological features were examined with a scanning electron microscope. The results demonstrated a high degree of structural preservation of no-touch SV preparations for CABG, including the endothelium, media, and the adventitia with the vasa vasorum. In contrast, a high degree of damage due to mechanical trauma was observed in SV harvested by conventional techniques. There were structural changes to the intima of these segments. In addition, remnants of the adventitial vasa vasorum were exposed to the outer environment. The possible pathophysiological implications of conventionally prepared grafts and the beneficial consequences of using the no-touch technique, in relation to CABG history, are discussed.