Association between paraoxonase activity and late saphenous vein graft occlusion in patients with coronary artery bypass grafting.

BACKGROUND Coronary vein graft disease is an important contributor to the morbidity after coronary artery bypass grafting (CABG). Late occlusion of the graft is a serious complication that limits the use of the saphenous vein as a coronary bypass conduit. It is frequently encountered in old, degenerated vein grafts with advanced atherosclerotic plaque formation. Paraoxonase-1 (PON-1) is an HDL-bound enzyme which has anti-atherogenic properties and protects LDL cholesterol from oxidative modification. AIM To examine the association between PON-1 activity and late saphenous vein graft occlusion. METHODS Thirty-eight patients who had at least one occluded saphenous vein graft (group 1; 12 females, 26 males) and 41 patients who had a patent saphenous vein graft (group 2; 7 females, 34 males) were enrolled in this study. Paraoxonase activity was measured spectrophotometrically. RESULTS The mean PON-1 activity in group 1 was significantly lower than in group 2 (74.1 +/- 52.1 vs. 114.4 +/- 90.9 U/l, p = 0.02). The mean platelet volume was significantly higher in group 1 than group 2 (8.8 +/- 1.6 vs. 8.2 +/- 1.1 fl, p = 0.04). Multiple logistic regression analysis showed that only PON-1 activity (beta = 0.011, p = 0.042) was an independent predictor of late occlusion of a saphenous vein graft. CONCLUSIONS Our results show that PON-1 activity is lower in patients with late saphenous vein graft occlusion. Reduced PON-1 activity may lead to acceleration of saphenous vein graft occlusion.