Early Stage of Atherosclerosis in Aortocoronary Saphenous Vein Grafts: Intravascular Ultrasound Study

Introduction: Angiographically visible plaques in patent vein grafts are usually detected years after surgery. Our aim was to examine early plaque formation in vein grafts. Methods: Bypass angiography and intravascular ultrasonography (IVUS) examination were performed on 77 aortocoronary saphenous vein grafts (SVGs) implanted in 36 patients during the first 2 years after CABG. In each graft, a good quality 25 mm ultrasound image was analyzed. We measured: plaque area, lumen area, external elastic membrane (EEM) area, graft area and wall area. For the comparative assessment of SVGs, the index plaque area/EEM area was calculated. Data were analyzed for the following 4 time periods: I-0-4 months (22 grafts), II-5-8 months (23 grafts), III-9-12 months (19 grafts) and IV-13-16 months (13 grafts) after CABG. Student's t and Fisher-Snedecor tests were used for the purpose of statistical analysis in this retrospective study. Results: In period I, plaque formation (neointimal) was observed in 10 grafts (45%), with a mean plaque area of 1.59 mm(2), in 6 grafts (26%) in period II, with a mean plaque area of 1.03 mm(2) and in 15 grafts (71%) in period III, with a mean plaque area of 1.41 mm2, and in all (100%) grafts in period IV, with mean plaque area of 2,3 mm(2). Average index plaque area/EEM area in periods I, II, III and IV were 0.12, 0.08, 0.13 and 0.22. We have showed a significant plaque increase between periods II and IV(P=0.038). Conclusion: IVUS showed plaque in about 40% of venous grafts during the first year after CABG. Between 13-16 months plaque was visible in all studied grafts.