[Elevated levels of plasma homocysteine related to saphenous vein graft disease after coronary artery bypass graft surgery].

Elevated levels of plasma homocysteine may be an independent risk factor for coronary atherosclerosis. This study investigated whether plasma homocysteine levels are related to atherosclerotic lesions of saphenous vein grafts after coronary artery bypass surgery. Homocysteine levels were measured in fasting plasma by high-performance liquid chromatography and total cholesterol, triglyceride, high density lipoprotein cholesterol and lipoprotein (a) were also evaluated in 40 patients (mean age 65 +/- 8 years, mean interval after bypass surgery: 6.1 +/- 3.1 years, range 1-13 years). The vein graft disease group was defined as patients with angiographical stenosis of > or = 50% in any vein graft (n = 23). The other patients were defined as the no-vein graft disease group (n = 17). Patients who had a history of chronic renal failure or anatomic lesions of saphenous vein grafts were excluded. The distributions of homocysteine were skewed. Median homocysteine levels were 11.9 nmol/ml in all subjects. Homocysteine levels in the vein graft disease group were significantly higher than in the no-vein graft disease group (median 15.1 vs 10.6 nmol/ml, p = 0.01). In the analysis of plasma lipids, high-density lipoprotein cholesterol levels were significantly lower in the vein graft disease group than in the no-vein graft disease group (mean 37 +/- 11 vs 48 +/- 13 mg/dl, p = 0.01). Multiple regression analysis showed that elevated levels of homocysteine were an independent risk factor for saphenous vein graft disease after coronary artery bypass surgery. These findings indicate that elevated levels of plasma homocysteine are related to atherosclerotic lesions of saphenous vein grafts after coronary artery bypass surgery as well as coronary atherosclerosis.