Angiographic changes in saphenous vein grafts and atherosclerosis risk factors. A 5-year study with serial measurements of serum lipids and lipoproteins.

The association between cardiovascular risk factors and stenosis or occlusion of saphenous vein grafts was analysed in a prospective 5-year study of 176 unselected patients with coronary artery bypass grafting (CABG). Methods included serial measurements of serum lipids and lipoproteins, determination of apolipoprotein E phenotype, lipoprotein (a) levels 5 years postoperatively, and subcutaneous fat biopsy to determine the fatty acid composition before and one year after CABG. Graft angiography with quantitative analysis of angiograms was performed at the end of follow-up. A coronary artery with diameter < or = 1.5 mm was associated with occlusion of vein grafts (p < 0.01). The mean levels of serum lipids and lipoproteins, other traditional risk factors for atherosclerosis, and subcutaneous fatty acid composition were similar in patients with and without graft occlusion, and similar when the maximum diameter of non-occluded grafts was < 50% vs > or = 50%, and < 25% vs > or = 25%. High lipoprotein (a) concentration tended to be associated with obstructive changes in vein grafts. Our data indicate that, because lipids, lipoproteins and other traditional cardiovascular risk factors do not predict occlusion or stenosis of saphenous vein grafts five years after CABG, it is not currently possible to predict directly from the levels of these risk factors which patients are likely to benefit from pharmacological or other interventions.