Risk factors related to progressive narrowing in aortocoronary vein grafts studied 1 and 5 years after surgery.
Factors related to late narrowing of aortocoronary vein grafts are poorly understood. Repeat aortocoronary bypass graft angiography was performed in 34 patients at 13 +/- 5 months and 61 +/- 13 months after surgery. In these patients, 61 of 65 grafts (94%) were patent at 1 year; at 5 years, 39 of these patent grafts (64%) remained unchanged, 21 (34%) had become progressively narrowed and one (2%) was totally occluded. There appeared to be no predilection for progression to occur at specific segments or in particular grafts: Eight of 28 left anterior descending (29%), seven of 17 right coronary artery (41%) and seven of 16 circumflex artery grafts (44%) (NS) showed further narrowing. Progressive graft narrowing occurred in 15 of 34 patients (44%). Risk factors (incidence of smoking, diabetes mellitus, hypertension, and triglyceride and cholesterol levels) in these 15 patients were compared with those in the 19 patients whose grafts were unchanged between 1 and 5 years. The incidence of smoking, diabetes mellitus (fasting blood sugar greater than or equal to 110 mg % or 2-hour postprandial sugar greater than or equal to 140 mg %) and hypertension (systolic blood pressure greater than 140 mm Hg or diastolic pressure greater than or equal to 95 mm Hg) were 46%, 27% and 33%, respectively, in the patients with progressive graft narrowing and 68%, 16%, 26% in the patients whose grafts were unchanged (NS). The average mean triglyceride levels were 617 +/- 785 mg % (+/- SD) and 195 +/- 86 mg %, respectively (p less than 0.05). The average mean cholesterol levels were 279 +/- 53 mg % and 234 +/- 35 mg %, respectively (p less than 0.01). In patients who have had aortocoronary bypass surgery, total graft occlusion is rare between 1 and 5 years after surgery. Progressive narrowing of grafts is common and appears to be associated with elevated blood lipids.