Does remodeling occur in the diseased human saphenous vein bypass grafts? An intravascular ultrasound study

Background: Coronary artery remodeling is a common phenomenon in human athe rosclerotic arteries. Controversies exist concerning the presence of absenc e of the remodeling process in diseased human coronary saphenous vein bypas s grafts. The purpose of the study was to observe the vessel and lumen dime nsions in patients who had undergone saphenous vein grafting with intravasc ular ultrasound to find out whether the remodeling process exists in the di seased human saphenous vein bypass grafts. Methods: A total of 43 saphenous vein bypass grafts from 43 patients (39 males, 4 females, mean age 63 +/- 8 years); 1-16 years (mean 9.3 +/- 4.0 years) after grafting, who had not u ndergone previous catheter intervention, were studied using intravascular u ltrasound. The vessel, lumen and plaque area were measured at the lesion se gment as well as in the proximal and distal reference segments. The percent stenosis was calculated. Results: In 43 bypass grafts having severe stenos is before intervention, plaque was eccentric in 69.4% and concentric in 30. 6%. No calcification was detected in 75% cases and 25% cases has mild-moder ate intimal calcification. The vessel area in the lesion segment was 19.0 /- 9.7 mm(2), significantly larger than the proximal reference segment 12.8 +/- 4.0 mm(2) as well as the distal reference segment 12.9 +/- 3.6 mm(2) ( p < 0.001). It was also larger than that of the average area of the proxima l and distal reference segments (p < 0.001). The vessel area increased in a ccordance with plaque area (p < 0.001). A weak relationship existed between vessel area and percent stenosis (r = 0.37, p = 0.04). Conclusion: In cont rary to previous findings, diseased human saphenous vein bypass grafts unde rgo focal compensatory enlargement (remodeling) in the presence of plaque f ormation. The underlying mechanism is probably similar to that in de novo a therosclerosis.