Effects of Off-Pump and On-Pump Coronary-Artery Bypass Grafting at 1 Year

Study Questions:

What is the impact of coronary artery bypass grafting (CABG) performed with a beating-heart technique (off-pump) as compared to CABG performed with cardiopulmonary bypass (on-pump) on quality of life and cognitive function, and on clinical outcomes at 1 year?


The CORONARY (CABG Off or On Pump Revascularization Study) trial investigators enrolled 4,752 patients with coronary artery disease who were scheduled to undergo CABG and randomly assigned them to undergo the procedure off-pump or on-pump. Patients were enrolled at 79 centers in 19 countries. They assessed quality of life and cognitive function at discharge, at 30 days, and at 1 year, as well as clinical outcomes at 1 year. The time to the first occurrence of any one of the components of the primary outcome was described with the use of Kaplan–Meier survival curves, and the comparisons between the two study groups were performed with the use of a log-rank test.


At 1 year, there was no significant difference in the rate of the primary composite outcome between off-pump and on-pump CABG (12.1% and 13.3%, respectively; hazard ratio [HR] with off-pump CABG, 0.91; 95% confidence interval [CI], 0.77-1.07; p = 0.24). The rate of the primary outcome was also similar in the two groups in the period between 31 days and 1 year (HR, 0.79; 95% CI, 0.55-1.13; p = 0.19). The rate of repeat coronary revascularization at 1 year was 1.4% in the off-pump group and 0.8% in the on-pump group (HR, 1.66; 95% CI, 0.95-2.89; p = 0.07). There were no significant differences between the two groups at 1 year in measures of quality of life or neurocognitive function.


The authors concluded that at 1 year after CABG, there was no significant difference between off-pump and on-pump CABG with respect to the primary composite outcome, the rate of repeat coronary revascularization, quality of life, or neurocognitive function.


This study found no significant between-group difference at 1 year in the rate of the first coprimary outcome of death, nonfatal stroke, nonfatal myocardial infarction, or nonfatal new renal failure requiring dialysis; in the rate of each component of the coprimary outcome; or in the rate of repeat revascularization. Although there was a small difference in cognitive function in favor of off-pump CABG at discharge, this benefit did not persist at 1 year. The apparent differences in results between the ROOBY trial, which showed a significantly higher rate of the composite outcome at 1 year with off-pump CABG than with on-pump CABG, and CORONARY, may be due to differences in the baseline risk of the patients as well as the differences in the experience levels of the surgeons, but additional research is needed to definitively answer this question.

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Cardiac Surgery and Heart Failure, Interventions and Coronary Artery Disease

Keywords: Renal Dialysis, Incidence, Coronary Artery Disease, Myocardial Infarction, Stroke, Renal Insufficiency, Cardiopulmonary Bypass, Coronary Artery Bypass, Myocardial Contraction

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