ROOBY-FS Trial: Off-Pump CABG Inferior at 5 Years

Patrice Wendling

August 17, 2017

NEW YORK — Off-pump CABG showed no advantage across all 5-year clinical outcomes and a 3.3% significantly higher absolute risk of all-cause death in the  ROOBY-Follow-up Study (ROOBY-FS)[1].

In contrast, the recent 5-year findings of the international CORONARY trial showed similar outcomes with the more technically demanding off-pump approach and on-pump CABG.

"Our study, although some might criticize it compared with the others because there's not quite the surgical experience, the fact of the matter is it probably reflects better the current surgical experience of North America in terms of relevance," senior ROOBY-FS author Dr Frederick Grover (University of Colorado School of Medicine, Aurora) said in an interview.

Off-pump CABG was touted in the 1990s as a way to prevent the damaging neurocognitive effects of cardiopulmonary bypass. But its use has fallen in the US from 23% in 2002 to 13% in 2016, he noted.

The results support the conclusion that "off-pump CABG does not offer any substantial advantages over on-pump CABG except possibly in unusual situations such as, for example, in patients with an extensively calcified (porecelain) aorta, in whom the off-pump technique may result in less manipulation of the aorta, potentially decreasing the risk of aortic emboli or stroke," the authors write in the August 17, 2017 issue of the New England Journal of Medicine.

Liver-transplant patients and frail elderly patients with a high comorbidity burden may also benefit from off-pump CABG, Grover said.

"There are indications for off-pump, but we really do need to spell that out as we go forward," he added. "The literature is all over the place."

Asked to comment on the results, lead CORONARY author Dr André Lamy (McMaster University, Hamilton, ON) said, "I'm not surprised because the 1-year results of ROOBY show a difference in the primary outcomes, but ROOBY is a different animal on its own."

In 2009, the original VA-sponsored trial ROOBY trial reported no significant differences between the two approaches in 30-day clinical outcomes, including neurocognitive outcomes, but sparked controversy because the median surgical experience was just 50 cases and patients were typically lower risk and male.

This prompted the CORONARY trial, which required surgeons to have more than 2 years of experience with off-pump CABG and to have completed more than 100 cases; and the German Off-Pump Coronary Artery Bypass Grafting in Elderly Patients (GOPCABE) trial, where the median experience was 322 off-pump surgeries.

Despite these differences in surgical volume, CORONARY and GOPCABE showed no benefit of an off-pump approach for any of their primary 30-day or 1-year outcomes.

At 1 year in ROOBY, there was a trend toward better survival in the on-pump group and a significantly higher composite rate of all-cause death, nonfatal MI, or any repeat revascularization procedure in the off-pump group.

All three trials showed off-pump CABG results in less complete revascularization, which the ROOBY-FS authors note "may be a mechanism for the shorter survival that has been observed among patients who have undergone an off-pump procedure."

At 5 years, they report the rate of death was significantly higher in the off-pump group at 15.2% vs 11.9% in the on-pump group (relative risk [RR] 1.28; P=0.02).

The co–primary composite end point of all-cause death, nonfatal MI, or repeat revascularization was also significantly higher in the off-pump group (31.0% vs 27.1%; RR 1.14; P=0.046). The absolute difference was 3.9% (95% CI 0.1–7.6).

No between-group differences were observed for the secondary outcomes of nonfatal MI, CV death, repeat revascularization, and repeat CABG.

Notably, a large meta-analysis looking at short-term outcomes found no differences in the rate of MI and all-cause mortality between the two procedures, but a 28% relative reduction in the risk of stroke at 30 days with the off-pump procedure.

There was also a signal in the 5-year CORONARY results for a reduction in stroke in diabetic patients undergoing off-pump CABG.

"We are in the process of doing a number of subgroup analyses, but at 1 year we did look at diabetes and again found no benefit off-pump and actually they did better on-pump," Grover said.

Lamy said their finding in diabetic patients needs to be confirmed and that additional results are expected at the end of the year or early next year from GOPCABE.

Calls to abandon off-pump CABG are premature, however, although Lamy said his practice has changed over the last 10 years and "I'm doing more on-pump these days.

"Low-risk patients go on-pump and those I still like to do off-pump are much older, frail, and [those with] calcified aorta, of course," he added.

In an accompanying editorial,[2] Dr Eugene Blackstone (Cleveland Clinic, OH) and Dr Joseph Sabik III (University Hospitals Cleveland Medical Center, OH) write: "Although the controversy about on-pump vs off-pump CABG is likely to continue, it may be time to abandon this discussion and focus on identifying which patients benefit from which procedure."

They note that patients with an STS score of more than 3% appear to gain a survival advantage from off-pump CABG, while those aged 75 years and older appear to have a lower risk of stroke with off-pump CABG.

"It is time to change the discussion and choose the procedure that is best for the patient," the editorialists conclude.

The study was supported by a grant from the Department of Veterans Affairs Office of Research and Development Cooperative Studies Program and, in part, by the Offices of Research and Development at the Northport VA Medical Center and the Eastern Colorado Health Care System Denver VA Medical Center. Grover reports no relevant financial relationships. Disclosures for the coauthors are listed on the journal website. Blackstone reports no relevant financial relationships. Sabik reports being a member of a cardiac surgery advisory council for Medtronic. Lamy reported no financial disclosures.

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