Neurocognitive outcomes of off-pump versus on-pump coronary artery bypass: a prospective randomized controlled trial

Preliminary reports have documented the safety of off-pump coronary artery bypass graft compared with conventional coronary artery bypass graft surgery. Whereas off-pump coronary artery bypass graft surgery may be associated with improvement in some short-term outcomes, longer-term outcomes and influence on neurocognitive function have not been fully assessed. We examined short-term and intermediate-term neurocognitive and index admission morbidity and mortality after coronary artery bypass surgery performed with and without the use of extracorporeal circulation.

We prospectively randomly assigned 201 patients undergoing nonemergent isolated coronary artery bypass graft surgery to conventional coronary artery bypass graft surgery (n = 102) or off-pump coronary artery bypass graft surgery (n = 99). The primary end points of the study were neurocognitive function assessed using a 19-test neurocognitive battery at baseline, discharge, and 6 months. Neurocognitive deficit was defined as a 20% or greater reduction from baseline in at least 20% of the tests. Secondary end points included index admission mortality, stroke, low-output cardiac failure, return to the operating room for bleeding, and postoperative troponin release. Risk ratios and 95% confidence intervals were calculated based on intention-to-treat analysis.

There was no difference in neurocognitive deficit at discharge (discharge versus preoperative: risk ratio, 0.83; 95% confidence interval, 0.65 to 1.07) or at 6 months (6 months versus preoperative: risk ratio, 0.94; 95% confidence interval, 0.70 to 1.28). There was no significant difference in mortality or morbidity between the two groups. The off-pump coronary artery bypass graft group had fewer patients with troponin release than the conventional coronary artery bypass graft group.

Off-pump coronary artery bypass graft surgery did not result in decreased frequency of neurocognitive deficit. Off-pump coronary artery bypass graft surgery was associated with substantially lower levels of troponin release after surgery.