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SAN FRANCISCO -- When coronary artery bypass grafting is performed by experienced surgeons, there's no difference in longer-term cardiovascular outcomes between procedures done on-pump or off-pump, but off-pump may be better in high-risk patients, researchers reported here.

In two randomized controlled trials -- one of which focused on an elderly, high-risk population -- there were no differences in a cardiovascular composite endpoint at 1 year with or without cardiopulmonary bypass, according to Andre Lamy, MD, of McMaster University in Canada, and Anno Diegeler, MD, of Bad Neustadt Heart Center in Germany, told attendees at a late-breaking clinical trials session at the American College of Cardiology meeting.

Their studies were simultaneously published online in the New England Journal of Medicine.

A third trial reported better outcomes with the off-pump procedure in a high-risk population, according to Jan Hlavicka, MD, of Charles University Prague in the Czech Republic, who presented the results at the meeting.

"These papers probably temper the widespread enthusiasm for off-pump," Mark Davies, MD, PhD, of the Methodist DeBakey Heart & Vascular Center in Houston, said during a press briefing. "In the right hands, with a well-trained surgeon, with correctly selected patients, off-pump does well. But on-pump is absolutely not dead."

Davies told 麻豆传媒 that the results give "no strong argument to go off-pump," and that surgeons can continue to do the procedure on-pump.

But Miguel Quinones, MD, also of Methodist DeBakey in Houston, noted that in the U.S., the decision to go off-pump "is probably more driven by surgeon passion."

"In America, we don't have a clear-cut concept of patient selection," he said during a press briefing. "Hopefully, these data are going to bring some sobering news, and make people think more about who should be better for one procedure over the other."

Most CABG surgery has been done with cardiopulmonary bypass, but more recently some have postulated that avoiding the pump can improve outcomes. Trials, however, hadn't been clear, and the ROOBY study showed worse cardiovascular outcomes at 1 year for patients who had the surgery off-pump.

But there has been criticism of previous trials for not taking into account surgeon skill, which could impact outcomes. So the three trials presented at the ACC meeting -- CORONARY, GOPCABE, and PRAGUE-6 -- took surgeon expertise into account in their trial designs.

CORONARY Findings

In the CORONARY trial, Lamy and colleagues randomly assigned 4,752 patients from 79 centers in 19 countries who were having CABG surgery to either on-pump or off-pump procedures.

Surgeons had to have had more than 2 years of experience and completed more than 100 cases with their respective procedure.

The study had previously reported no significant differences between the two strategies at 30 days with regard to a composite endpoint of death, MI, stroke, or new renal failure.

The researchers reported similar findings at 1 year, with no major differences between groups at that point (12.1% for off-pump, 13.3% for on-pump).

Nor were there any significant differences at that time in terms of quality of life or neurocognitive function. But Lamy noted that there was a "low participation rate" of patients in these parameters, which could affect the results.

They also saw a nonsignificant trend toward a higher rate of repeat coronary revascularization when patients went off-pump (1.4% versus 0.8%) (HR 1.66, 95% CI 0.95 to 2.89, P=0.07).

Lamy said the discrepancy between their findings and the ROOBY study likely had something to do with the differences in surgeon experience, concluding that "in experienced hands, both procedures are reasonable options based on these mid-term results." The full trial will run 5 years.

GOPCABE Results

In the GOPCABE study, Diegeler and colleagues looked specifically at elderly patients who were at higher risk than populations in other studies. Again, all surgeons had to be experienced in their respective techniques.

A total of 2,539 patients, mean age 78, were randomized to on- or off-pump surgery, and the primary endpoint was a composite of death, stroke, MI, repeat revascularization, or new renal replacement therapy at both 30 days and 1 year.

There were no significant differences at 30 days (7.8% off-pump versus 8.2% on-pump), although repeat revascularization occurred more frequently after the off-pump procedure (1.3% versus 0.4%) (OR 2.42, 95% CI 1.03 to 5.72, P=0.04)

At 1 year, there were again no significant differences in the composite endpoint (13.1% versus 14%), and the increased risk of revascularization disappeared.

PRAGUE-6 Findings

In the PRAGUE-6 trial, Hlavicka and colleagues conducted a randomized, single-center trial in 206 patients who were perceived to be at higher risk. Their mean age was 74 and they had a EuroSCORE of 6 or higher.

Once again, all surgeons were very experienced in their respective procedures, and the primary endpoint was a combination of death, MI, stroke, and new renal failure.

At 30 days, they reported better outcomes for the off-pump group (20.6% hit the primary endpoint on-pump versus 9.2% of those off-pump) (HR 0.41, 95% CI 0.19 to 0.91, P=0.028).

Individually, going off-pump only had better outcomes with regard to MI at 30 days (12.1% versus 4.1%, P=0.048), with nonsignificant findings for the other components.

"I strongly believe in off-pump surgery in high-risk patients after this study," Hlavicka said during a press briefing.

Christopher Cannon, MD, of Brigham & Women's Hospital in Boston, who moderated the session during which the findings were presented, said the take-away appears to be that off-pump surgery "is something that should be available for very high risk patients at an expert hospital with people who are trained and familiar with how to do it."

Michael Mack, MD, of Stanford, who also moderated the panel, noted that PRAGUE-6 indicates "a very select group" of patients as candidates for off-pump surgery.

"As a card-carrying off-pump surgeon, I've been losing some enthusiasm for it based upon the [CORONARY and GOPCABE] presentations," Mack said. "But [PRAGUE-6] gives me some idea about who I should consider for off-pump surgery when I go back home."

Lamy agreed that lower-risk patients appear to do better on-pump, while higher-risk patients may do better off-pump, though he cautioned that more research into these subgroups is needed.

Michael Reardon, MD, of Methodist Cardiovascular Surgery Associates in Houston, who was not involved in the study or the panel, told 麻豆传媒 that the findings can also be reassuring to patients and general practitioners: "For the average consumer or for the referring doctor who doesn't do this all the time, you can take heart that if your heart surgeon does coronary bypass on-pump, they're not doing a bad thing."