[What are the guidelines for using a venous segment for an arterial bypass? General review].

Since the first femoropopliteal bypass, performed by J. Kunlin, in 1950, the saphenous vein has remained the material of choice for arterial bypass in a wide variety of localizations. Harvesting must be adapted to vein quality and the length necessary for the bypass. A thorough knowledge of the histological structure of the graft and the impact of the harvesting process on endothelial cells is needed to understand early and late complications related to saphenous harvesting. Several experimental studies and clinical series, particularly for aortocoronary bypass, have shown the role of atraumatic harvesting, removing the perivenous fat, and/or papaverine infusion in the perivascular tissues. A venous graft can be used in six localizations. For femoropopliteal bypass, the venous graft can be used reversed or in situ, after valvular section. For bypass to tibial vessels and bypass to the ankle and the foot, the graft can be the greater saphenous vein or the lesser saphenous vein, or veins from the arm. These bypasses can be done reversed or in situ or transposed reversed or after valvular disruption. This technique has the advantage of placing the largest portion of the vein at the level of the proximal anastomosis, but with the risk of endothelial cell desquamation during vein harvesting, which can lead to late fibrosis of the graft. For aorto-iliac bypass, new prosthetic grafts and the development of endovascular techniques have overshadowed the former advantages of the saphenous vein grafts. Surgical renal revascularisations have become less frequent since the development of endovascular techniques. Nevertheless, the venous graft remains useful for some revascularisations - hepatic-renal bypass, iliorenal bypass, difficult nephrologic situations (solitary kidney, chronic occlusion). For aortocoronary bypass, long-term outcome has been studied in many studies. It is recommended to use the grafts with a no touch technique, using a portion without valves. The carotid venous graft is a useful technique when endarterectomy is difficult or not satisfactory. The graft must be harvested from the calf, without valves, have a diameter of 5mm and be harvested without injury.