Objectives: Saphenous vein grafts are common among patients with a history of coronary artery bypass graft (CABG) surgery. Chronic kidney disease (CKD) is an established cardiovascular risk factor, but its role in graft disease has not been evaluated.
Methods and results: The Post-CABG Trial randomized 1351 patients who had undergone CABG surgery 1-11 years earlier to high- or low-dose lovastatin and to low-dose warfarin or placebo. Coronary angiography was conducted at baseline and after a median follow-up time of 4.2 years. Subjects were grouped according to their baseline estimated glomerular filtration rate (eGFR). The primary trial endpoint was significant graft disease progression assessed angiographically. Additional pre-defined endpoints included occlusion of grafts patent at baseline, change in minimum lumen diameter, and a composite endpoint of recurrent clinical events. Decreasing eGFR was associated with an increased risk of graft occlusion (P(trend)=0.040), but not substantial atherosclerotic progression (P(trend)=0.30), per-graft change in minimum lumen diameter (P(trend)=0.067), or recurrent clinical events (P(trend)=0.86). We did not observe significant effect modification of treatment effects by the presence of CKD.
Conclusions: CKD may be associated with increased risk of atherosclerotic plaque disruption rather than atherosclerotic progression in saphenous vein grafts.