Early stage of atherosclerosis in aortocoronary saphenous vein grafts: intravascular ultrasound study

ABSTRACT

Abstract 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., in 6 grafts (26%) in period II, with a mean plaque area of 1.03 mm. and in 15 grafts (71%) in period III, with a mean plaque area of 1.41 mm., and in all (100%) grafts in period IV, with mean plaque area of 2,3 mm.. 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.