On-Pump CABG Does Not Impair Cognition More Than Off-Pump


Coronary-artery bypass grafting (CABG) has traditionally been performed with the use of cardiopulmonary bypass (on-pump CABG). When the CABG procedure is done without cardiopulmonary bypass it is referred to as an off-pump CABG.

Frederick L. Grover, MD, of the Denver VA Medical Center and University of Colorado Denver, and colleagues compared the two procedures, reporting their results in the Nov 5 issue of the New England Journal of Medicine. The researchers found on-pump CABG doesn't impair outcomes or cognition any more than off-pump CABG procedures.

The trial randomly assigned 2203 patients scheduled for urgent or elective CABG to either on-pump or off-pump procedures. There was no significant difference between off-pump and on-pump CABG in the rate of the 30-day composite outcome (7.0% and 5.6%, respectively). This short-term composite outcome included deaths or complications such as reoperation, new mechanical support, cardiac arrest, coma, stroke, or renal failure) before discharge or within 30 days after surgery.


On-pump CABG beat out off-pump CABG in the 1-year composite outcome (9.9% vs. 7.4%). The primary long-term end point was a composite of death from any cause, a repeat revascularization procedure, or a nonfatal myocardial infarction within 1 year after surgery.

The proportion of patients with fewer grafts completed than originally planned was higher with off-pump CABG than with on-pump CABG (17.8% vs. 11.1%). Follow-up angiograms in 1371 patients who underwent 4093 grafts revealed that the overall rate of graft patency was lower in the off-pump group than in the on-pump group (82.6% vs. 87.8%).

There were no treatment-based differences in neuropsychological outcomes between on- and off-pump procedures (composite z score change 0.17 versus 0.19).

Despite its size and rigorous design, the study is unlikely to end the debate over the heart-lung machine in CABG. Even though nearly one in five CABG procedures carried out in the U.S. is performed off-pump, "the rate of use of the technique varies from 0% to more than 80% among hospitals," Peterson said.

Shroyer AL, et al "On-pump versus off-pump coronary-artery bypass surgery" N Engl J Med 2009; 361: 1827-37.
Peterson ED, et al "Innovation and comparative-effectiveness research in cardiac surgery" N Engl J Med 2009; 361: 1897-99.