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27-03-2013 | Cardiology | Article

Pump conundrum settled in heart bypass surgery



medwireNews: Off-pump coronary artery bypass grafting (CABG) is no better or worse than on-pump surgery, two large randomized trials show.

Clinical outcomes were similar with both techniques at 1 year after surgery, show the findings in The New England Journal of Medicine.

In an accompanying editorial, John Alexander (Duke Clinical Research Institute, Durham, North Carolina, USA) writes: "It is safe to conclude that on-pump and off-pump surgery, if performed by appropriately experienced surgeons, result in similar short-term and 1-year outcomes."

But he cautions: "Given the known learning curve for off-pump surgery, its use should be limited to surgeons who are experienced with off-pump techniques."

Both trials required surgeons to have extensive experience in their procedure, addressing the previous findings of the Randomized On/Off Bypass (ROOBY) trial. This reported poorer 1-year outcomes with off-pump than on-pump surgery, but variable surgeon skill with off-pump surgery has been proposed as an underlying factor.

The largest of the two current studies - the CABG Off or On Pump Revascularization Study (CORONARY) - involved 4752 patients in need of CABG who were randomly assigned to undergo on-pump or off-pump surgery. The composite primary endpoint of death, and nonfatal stroke, myocardial infarction (MI), or renal failure occurred in 12.1% and 13.3% of patients in the off-pump and on-pump groups, respectively.

This difference was not significant, and there were no between-group differences in rates of angina or repeat revascularization, report André Lamy (McMaster University, Hamilton, Ontario, Canada) and team. In addition, the type of surgery did not affect neurocognitive outcomes among the 2850 patients who provided data.

The other study was the German Off-Pump Coronary Artery Bypass Grafting in Elderly Patients (GOPCABE) study, conducted by Anno Diegeler (Cardiovascular Clinic Bad Neustadt, Germany) and co-workers. The team explored the idea that high-risk, elderly patients might benefit from avoiding cardiopulmonary bypass, but again found that the type of surgery did not affect clinical outcomes.

The trial included 2539 patients aged at least 75 years; at 1 year after CABG, 13.1% and 14.0% of those assigned to off-pump and on-pump surgery, respectively, had a primary endpoint event (death, MI, stroke, renal failure). There was also no difference in a per protocol analysis; however, more patients needed revascularization after off-pump than on-pump surgery, at 1.3% versus 0.4%.

Alexander says that a greater need for revascularization with off-pump surgery is a consistent trend, as is fewer transfusions, but notes that it is not clear if these complications "adversely affect outcomes that are important to patients."

He says: "The two studies published in this issue substantially increase the body of evidence with regard to off-pump surgery; however, even they are underpowered to detect a moderate reduction in stroke, the most likely benefit of off-pump surgery."

By Eleanor McDermid, Senior medwireNews Reporter

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