ABSTRACT
Examination of totally or partially obstructed human aortocoronary vein grafts, obtained at different time intervals after the bypass operation, has shown that the initial occlusive process is due to thrombosis and may appear a few hours or days after surgery. The cellular phase of intimal proliferation affecting most of the grafts becomes apparent about 4 weeks after the operation. After 1 year the intimal hyperplasia acquires a cell-poor, fibrotic character; the graft usually remains patent. About one-half of the vein grafts obtained 3 or more years after the operation show complicated atherosclerotic lesions. These findings indicate that most of the vein grafts undergo extensive structural changes and some may show similar degenerative lesions as they develop in the coronary arteries.
Subject(s)
Coronary Artery Bypass , Saphenous Vein/ultrastructure , Graft Survival , Humans , Microscopy, Electron, Scanning , Middle Aged , Saphenous Vein/transplantation , Transplantation, AutologousABSTRACT
Aortocoronary vein grafts removed at autopsy of 182 patients who died up to 5 years after the bypass operation were examined by light and electron microscopy. During the first month after surgery, graft occlusion was due to thrombi, some of them recent, some organized and recanalized. Intimal proliferation of the graft first appeared 4 weeks after the bypass surgery; several cases of total occlusion of the lumen by this process were seen within 6 months of the operation. A change in the morphological features of the intimal thickening from cellular to fibrotic and hylain-like was observed in several grafts implanted for more than 1 year. Typical atherosclerosis developed in vein grafts in three of the six patients surviving the operation for more than 3 years.
Subject(s)
Coronary Artery Bypass/mortality , Saphenous Vein/transplantation , Adult , Aged , Coronary Disease/pathology , Female , Humans , Male , Middle Aged , Saphenous Vein/pathology , Transplantation, AutologousABSTRACT
Aorta-coronary artery vein grafts, obtained from 2 patients 37 and 59 months after an aorta-coronary bypass operation, showed extensive mural changes characterized by degenerative tissue lesions, loss of normal morphological features of the intima, and extracellular accumulation of lipids. Both patients had increased plasma triglyceride levels.
Subject(s)
Coronary Artery Bypass , Coronary Disease/epidemiology , Veins/transplantation , Venous Insufficiency/etiology , Adult , Arteriosclerosis/pathology , Cholesterol Esters , Coronary Disease/pathology , Endothelium/ultrastructure , Follow-Up Studies , Humans , Male , Microscopy, Electron, Scanning , Necrosis , Saphenous Vein/ultrastructure , Venous Insufficiency/pathologyABSTRACT
Pathological changes in aortocoronary vein grafts were investigated in 17 patients who had a second revascularization procedure 1 to 53 1/2 months after their initial operation. Subendothelial proliferation was present in all grafts and had resulted in total occlusion of 7. With increasing duration of implantation the proliferative lesions tended to show hyalinization and to affect the media. Advanced atherosclerosis had developed in 2 grafts.
Subject(s)
Arteriosclerosis/pathology , Coronary Artery Bypass , Saphenous Vein/pathology , Veins/transplantation , Adult , Coronary Artery Bypass/adverse effects , Female , Follow-Up Studies , Humans , Male , Middle Aged , Time Factors , Transplantation, AutologousABSTRACT
Scanning electron microscope study of two vein grafts which were removed after 50 months of implantation as aorta-coronary artery vein grafts showed considerable subendothelial thickening, which consisted of relatively cell-poor fibrous layer. In one of the grafts the endothelial surface was intact; the second graft showed focal loss of endothelial cells. Sections of two fresh human veins, studied prior to their insertion as aorta-coronary artery vein grafts, have shown that they retained an intact endothelial layer. A third fresh vein, however, showed focal damage with missing endothelial cells and adherent fibrin.
