[Venous grafts as arterial substitutes. Immediate and medium-term development].

This study, based on the authors' experiments in dogs and on data from the literature, describes the immediate and mediumterm histological development of autologous vein grafts. Dissection alone results in extensive endothelial cell desquamation, which may be aggravated by distension and preservation of the graft in an inappropriate medium. Immediately after re-establishment of the arterial blood flow the inner surface of the graft is covered by a fibrinoerythrocytic membrane. Endothelialization begins 10-15 days later but remains incomplete in dogs after 9 months; it is not limited to the suture lines but proceeds by islets disseminated over the surface. As early as the 15th post-operative day, a myo-intimal layer of myofibroblastic cells develops; the origin and control of these cells are still unknown. A better knowledge of the histological development of vein grafts and underlying mechanisms appears to be essential to improvements in surgical procedures and subsequent long-term functional performance of the grafts.