Coronary artery bypass graft failure after on-pump and off-pump coronary artery bypass: findings from PREVENT IV

Background. This analysis compares 1-year vein graft patency and major adverse cardiac and cerebral events (MACCE [death, myocardial infarction, or stroke]) in on-pump and off-pump patients enrolled in PREVENT IV (the PRoject of Ex-vivo Vein graft ENgineering via Transfection IV). Methods. The PREVENT IV was a multicenter (107 sites) randomized trial of edifoligide to prevent vein graft failure from neointimal hyperplasia in 3,014 patients undergoing primary, isolated coronary artery bypass grafting (CABG) with at least two vein grafts. One-year angiographic follow-up was completed on 1,920 patients (4,736 grafts) with MACCE follow-up on 99.4% of enrolled patients. Results. In all, 2,377 procedures (78.9%) were on pump and 637 (21.1%) were off pump. On-pump patients had more chronic lung disease (17% versus 11%; p < 0.001), congestive heart failure (10% versus 7%; p = 0.03), lower mean ejection fraction (50% versus 55%; p < 0.001), and worse target artery quality (good 63.8% versus 68.1%; fair 26.4% versus 22.7%; poor 9.8% versus 9.2%; p < 0.001). Vein graft failure (more than 75% graft stenosis) in on-versus off-pump patients was 25.3% versus 25.7% (p = 0.62). After adjusting for differences in significant predictors of vein graft failure (target artery quality, surgery time, endoscopic vein harvest, more than 1 distal anastomosis/graft, and patient weight), the odds of vein graft failure was 0.82 (95% confidence interval: 0.67 to 1.00; p = 0.05) for on-pump versus off-pump patients. One-year mortality for on-versus off-pump patients was 3.3% versus 2.5% (p = 0.30); and MACCE was 15.4% versus 11.3% (p = 0.01). The adjusted hazard ratio for 1-year MACCE was 1.31 (95% confidence interval: 1.01 -1.69; p = 0.01) for on pump versus off pump. Conclusions. Observed saphenous vein failure rate was 25% in both groups. One-year clinical outcomes (MACCE) were better with off-pump than with on-pump CABG, suggesting benefits not related to vein graft patency.