Dr. Andre Lamy
Dr. Andre Lamy presented the 1-year results. The primary endpoint was a composite of death, MI, stroke, or new renal failure requiring dialysis. The rate was 12.1% in patients in the off-pump group and similar at 13.3% in the on-pump group.
As in GOPCABE, the surgeons participating in CORONARY were highly proficient. They had to have at least 2 years’ experience as a staff cardiac surgeon and at least 100 prior cases of whichever operation they were assigned to. The vast majority met that standard for both procedures.
Quality of life and neurocognitive tests were conducted preoperatively, at discharge, at 30 days, and again at 1 year. Quality of life as assessed by the European Quality of Life-5 Dimensions (EQ-5D) questionnaire showed significant improvement over time in both study arms, with no difference between the two groups.
Nor were there any significant between-group differences in neurocognitive function as assessed using the Montreal Cognitive Assessment, the Digit Symbol Substitution Test, and the Trail Making Test Part B. However, neurocognitive testing was declared optional because it’s so time consuming, and many patients opted out. For example, only 1,273 of the original 4,752 patients returned to take the Montreal Cognitive Assessment at 1 year, noted Dr. Lamy, a heart surgeon at the Population Health Research Institute at McMaster University in Hamilton, Ont.
Discussant Dr. Bernard Gersh zeroed in on the incomplete neurocognitive testing.
“I think this is really a significant limitation. There’s a huge bias. If there’s any advantage to off-pump CABG, it may be in neurocognitive dysfunction,” commented Dr. Gersh, professor of medicine at the Mayo Clinic, Rochester, Minn.
In response to the discussants’ questioning as to where off-pump CABG fits into clinical practice in light of the disappointing CORONARY and GOPCABE findings, Dr. Diegeler said he remains convinced that some high-operative-risk patients – those with aortic calcification or other evidence of generalized vascular disease ‑ do benefit preferentially from off-pump surgery when performed by expert surgeons.
“It’s hard to prove that in a randomized clinical trial, though,” the surgeon conceded.
Dr. Lamy said a post hoc analysis of the CORONARY data showed that low-operative-risk patients as defined by a EuroScore of 0-2 tended to do better with on- than off-pump CABG, while the converse was true in those with moderate- or high-risk scores.
“In my personal practice now, my low-risk patients go on-pump and my moderate- and high-risk patients go off-pump,” he added.
Dr. Jan Hlavicka
Both surgeons were firmly in favor of off-pump CABG continuing to be available at expert centers so that surgeons can individualize their operation to suit a patient’s needs.
Dr. Jan Hlavicka presented the results of the PRAGUE-6 trial, in which 206 patients at high operative risk – a EuroScore of 6 or greater – were randomized to off- or on-pump CABG at Charles University, Prague. The operations were performed by five surgeons proficient in both procedures.
The 30-day primary composite endpoint comprising death, MI, stroke, or new renal failure requiring dialysis occurred in 20.6% of the on-pump group, compared with 9.2% of off-pump patients.
The off-pump group required significantly fewer RBC transfusions. However, there were no significant differences between the two groups in terms of average hospital length of stay, wound infection rates, or total hospital costs.
“We believe off-pump bypass in high-risk patients has a lower incidence of serious complications and is a safer means of direct revascularization in these patients,” concluded Dr. Hlavicka, a cardiac surgeon at the university.
Dr. Gersh noted that the only significant difference between the two groups in the individual components of the primary endpoint was in acute MI rates: 12.1% in the on- vs. 4.1% in the off-pump CABG group. He took issue with the Czech investigators’ use of the 2004 Society of Thoracic Surgeons definition of acute MI, which in the first 24 hours after surgery requires only an elevation of creatine kinase–MB at least five times the upper limit of normal with no need for new Q waves. That’s not sufficiently stringent. It surely captures many patients who don’t really have an acute MI. The data should be reanalyzed using a contemporary definition which requires new Q waves, he added.
The CORONARY trial was funded by the Canadian Institutes of Health Research; simultaneous with Dr. Lamy’s presentation of the data in San Francisco, the study was published online (N. Engl. J. Med. 2013 [doi:10.1056/NEJMoa1301228]).
The GOPCABE trial was sponsored by the German Society for Cardiovascular Surgery with funding support by Maquet. It was published online simultaneously with Dr. Diegeler’s ACC presentation (N. Engl. J. Med. 2013 [doi:10.1056/NEJMoa1211666]).