Two large trials presented at the American College of Cardiology meeting in San Francisco and published simultaneously in the New England Journal of Medicine provide important new information about the ongoing debate over whether CABG should be performed with or without cardiopulmonary bypass. The combined results suggest that both techniques can be effective, and that surgeons should choose the technique with which they are most familiar and comfortable.
Previous 30-days results from CORONARY (CABG Off or On Pump Revascularization Study), which randomized 4,752 patients to on-pump or off-pump CABG, showed no significant difference in the primary outcome (death, MI, stroke, or new renal failure requiring dialysis) between the two groups. However, patients in the off-pump group required more repeat revascularization procedures, though they had lower rates of bleeding, acute kidney injury, and respiratory complications.
Now, one-year results from CORONARY have found no significant difference in the primary outcome between the groups at 1 year (12.1% in the off-pump group versus 13.3% in the on-pump group (HR 0.91, CI 0.77-1.07, p=0.24). There were also no significant differences in the individual components of the endpoint. In addition, there were no significant differences in recurrent angina (1% versus 0.9%) or the need for repeat revascularization (1.4% versus 0.8%).
A quality of life substudy found no differences between the two groups at any time point in the first year. A neurocognitive substudy found less deterioration in one assessment of neurocognitive function in the off-pump group at discharge but found no significant differences at 30 days or at 1 year. There were no differences at any time between the two groups in two other tests of neurocognitive function.
“The CORONARY study shows that off-pump bypass is just as good as on-pump. Therefore, surgeons should tailor their surgical approach to their technical expertise and expected technical difficulty,” said Andre Lamy, lead author of the study, in an ACC press release.
In the GOCABE (German Off-Pump Coronary Artery Bypass Grafting in Elderly Patients) study, 2,539 patients 75 years of age or older were randomized to on-pump or off-pump CABG. The primary endpoint was the composite of death, stroke, MI, repeat revascularization, or new renal-replacement therapy at 30 days and one year.
At 30 days there was no significant difference in the primary endpoint: 7.8% for the off-pump group versus 8.2% for the on-pump group (OR 0.95, CI 0.71-1.28, p=0.74). However, there were more repeat revascularizations in the off-pump group at 30 days: 1.3% versus 0.4%, OR 2.42, CI 1.03-5.72, p=0.04. At one year there were no significant differences between the groups in the composite endpoint (13.1% versus 14%, HR 0.93, CI 0.76-1.16, p=0.48) or in any of the individual components of the composite endpoint.
The authors write that their trial “does not support the assumption that off-pump CABG can improve the early outcome in high-risk patients.”
During the discussion section lead investigators for both studies, Anno Diegeler for GOCABE and Andre Lamy for CORONARY, emphasized that their results depended on having expert surgeons highly qualified in both techniques.
Choice of the technique, said Diegeler, should depend on clinical characteristics, patient choice, and surgeon experience.
Chris Cannon, a panel discussant, asked the question:”why would you want to do off-pump since it’s no better and it’s harder to do?” At the ACC news conference, Mark Davies said that “these trials may temper our enthusiasm for off-pump surgery.” In the US, with the advent of publicly reported STS (Society for Thoracic Surgeons) scores for individual hospitals and amateurs, there will no room for amateurs. “If you’re an amateur at it you should give it up.” Neil Kleiman had a recommendation: “if you’re going to do it you damn well better be good at it… there’s no room for sloppiness.”