Off-Pump Coronary Artery Bypass Surgery Is Associated With Worse Arterial and Saphenous Vein Graft Patency and Less Effective Revascularization: Results From the Veterans Affairs Randomized On/Off Bypass (ROOBY) Trial
What is the relative efficacy of off-pump versus on-pump coronary artery bypass graft (CABG) surgery?
From February 2002 to May 2007, the ROOBY trial randomized 2,203 patients to off-pump versus on-pump CABG. Follow-up angiography was obtained in 685 (62%) off-pump and 685 (62%) on-pump patients. Angiograms were analyzed (blinded to treatment) for FitzGibbon classification (A = widely patent, B = flow limited, O = occluded) and effective revascularization. Effective revascularization was defined as follows: all of the three major coronary territories with significant disease were revascularized by a FitzGibbon A quality graft to the major diseased artery, and there were no new post-anastomotic lesions.
Off-pump CABG resulted in lower FitzGibbon A patency rates than on-pump CABG for arterial conduits (85.8% vs. 91.4%, p = 0.003) and saphenous vein grafts (SVGs) (72.7 vs. 80.4%, p < 0.001). Fewer off-pump patients were effectively revascularized (50.1% vs. 63.9% on-pump, p < 0.001). Within each major coronary territory, effective revascularization was worse off-pump than on-pump (p values all ≤ 0.001). The 1-year adverse cardiac event rate was 16.4% in patients with ineffective revascularization versus 5.9% in patients with effective revascularization (p < 0.001).
The authors concluded that off-pump CABG resulted in significantly lower FitzGibbon A patency for arterial and SVG conduits, and less effective revascularization than on-pump CABG.
The major finding from this analysis was that graft patency was consistently and significantly worse with off-pump CABG. This was true for all three major coronary regions, including grafts to the left anterior descending artery (LAD) territory. Furthermore, incomplete or ineffective revascularization was associated with worse cardiovascular outcomes at 1 year. Patients who had one or more poorly revascularized territories or ineffective LAD territory revascularization had high 1-year adverse event rates that were significantly worse than subjects who were effectively revascularized. Further long-term follow-up of the ROOBY trial patients will help determine whether the adverse outcome differences between the two arms diverge further or converge over time. For now, on-pump CABG appears to be the preferred modality for most patients.
Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention
Keywords: Vascular Patency, Veterans, Saphenous Vein, Coronary Artery Bypass, Off-Pump
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