Predictors of Aorto-Saphenous Vein Bypass Narrowing Late After Coronary Artery Bypass Grafting

The objective of this study was to evaluate the clinical and angiographic factors associated with significant saphenous vein graft (SVG) atherosclerosis progression at mid-term follow-up in a series of unselected coronary patients who had previously received a coronary artery bypass graft (CABG). A total of 123 SVGs from 86 patients who underwent cardiac catheterization twice, 15 ± 12 months apart, were included in the study. None of the SVGs presented any ≥50% diameter stenosis (DS) lesion or underwent any intervention at baseline. All SVGs were divided into 3 segments and each SVG segment was scored from 0 to 3 depending on the presence of lesions, with percent DS ranging from 0% to 19% (score 0), 20% to 29% (score 1), 30% to 39% (score 2), and ≥40% (score 3). The SVG atherosclerotic burden score (ABS) was calculated by adding the score obtained for each of the 3 SVG segments. Significant progression was defined as ≥10% increase in lesion percent DS or ≥0.6 mm decrease in minimal lumen diameter between baseline and follow-up studies. Mean age of the study population was 66 ± 9 years, and most of the patients were receiving statin therapy with mean low-density lipoprotein cholesterol of 85 ± 26 mg/dl. Significant angiographic progression occurred in ≥1 SVG in 41 patients (48%). On multivariate analysis, the variables associated with SVG atherosclerosis progression were SVG ABS (odds ratio [OR], 1.52 for each increase of 1 point in SVG ABS; 95% confidence interval [CI] 1.1 to 2.29) and high-density lipoprotein (HDL) cholesterol (OR 1.38 for each decrease of 5 mg/dl in HDL cholesterol levels, 95% CI 1.09 to 1.85). Twenty-two patients (26%) had a cardiac event at follow-up related to SVG disease progression. The percent DS of the SVG segment at baseline was associated with SVG disease progression leading to a cardiac event (OR 3.67 for each increase of 5% in percent DS, 95% CI 2.11 to 6.38). In conclusion, simple clinical and angiographic variables such as HDL cholesterol, ABS, and lesion severity remain independent predictors of significant SVG atherosclerosis progression in mild to moderately diseased SVGs despite mean low-density lipoprotein levels <90 mg/dl.