Atherosclerosis and late closure of aortocoronary saphenous vein grafts

Sequential control angiographic examinations were performed at 2 weeks, 1 year, 5 to 7 years, and 10 to 12 years after aortocoronary saphenous vein bypass surgery in 82 unselected patients. Graft modifications consisting of wall irregularities and obstructive lesions of various severity and shapes that were found to develop after the first year were attributed to atherosclerosis. The incidence of these late changes increased from 16% during the interval between year and 5 to 7 years to 36.4% during the subsequent interval between 7 and 12 years (p <.01). These changes were not influenced by the severity of early diffuse or localized intimal hyperplasia. They were not related to classical risk factors except for low-density lipoprotein and low-density β-lipoprotein cholesterol. Graft closure increased 2.5-fold from the interval between 1 year and 5 to 7 years to the following period between 7 and 12 years, 10.2% to 26.1% (p <.02); thus the mean yearly attrition rate augmented from 2% to 5.3%. Late graft closure may result from early localized stenosis most likely related to improper surgical techniques, but the most frequent cause appears to be atherosclerosis. Graft patency at 10 to 12 years is 63.3%.