Natural course of the functional and morphological changes in canine autogenous arterial graft

Background: We examined the time course of endothelium-dependent and -indep endent responses in reversed autogenous arterial grafts during regeneration and tissue repair processes after arterial grafting in dogs. Materials and Methods: Autogenous arterial grafts implanted in the canine femoral artery were removed, cut into rings and suspended in organ chambers for isometric tension recording on the 1st, 3rd, 7th, 14th and 28th days after implantat ion. Electron-microscopic examination on the 1st, 3rd,7th, 14th and 28th da ys after transplantation was also performed. Control arteries were taken fr om nonsurgically treated femoral arteries. Results: Acetylcholine (ACh) and A23187 caused endothelium-dependent relaxations in arterial grafts through out the study. Although endothelium-dependent relaxations to ACh and A23187 on the 3rd day after transplantation were only significantly impaired comp ared to those of control, they were similar to the control within 1 week af ter grafting. Smooth muscle relaxations in response to sodium nitroprusside in arterial grafts throughout the study were comparable with those of cont rol arteries. No apparent intimal thickening of the arterial grafts was obs erved. Electron microscopy scanning revealed mild endothelial cell damage i n implanted autogenous arterial grafts on the 1st or 3rd day after grafting . Seven to 14 days after grafting, the endothelial cell layer appeared to b e normal. Conclusions: It was observed that the endothelial function remain ed intact and there was an absence of intimal thickening in the arterial gr afts. These observations may explain the improved patency of autogenous art erial grafts compared to the vein grafts in aortocoronary revascularization . Copyright (C) 2001 S. Karger AG. Basel.