Morphologic changes in long-term saphenous vein bypass grafts.

A retrospective autopsy study was performed in 56 patients who had undergone saphenous vein bypass graft (SVBG) surgery 12 to 168 months prior to death. Twenty-five grafts had atherosclerosis, 66 grafts had fibrointimal proliferation, and 26 grafts were fibrotic with total occlusion. No significant differences were noted among the three morphologic groups with regard to age of the patient or number of native coronary arteries severely narrowed. Vein grafts with fibrointimal proliferation occurred with greater frequency in patients with systemic hypertension (p less than 0.001), and atherosclerotic grafts were more prevalent in patients with hypercholesterolemia (p less than 0.02). Therefore, the presence of risk factors may determine the type of change that occurs in saphenous vein bypass grafts: systemic hypertension leads to fibrointimal proliferation, whereas hypercholesterolemia leads to atherosclerotic change.