Cognitive outcome after off-pump and on-pump coronary artery bypass graft surgery: a randomized trial

Abstract

Context: Coronary artery bypass graft (CABG) surgery is associated with a decline in cognitive function, which has largely been attributed to the use of cardiopulmonary bypass (on-pump procedures). Cardiac stabilizers facilitate CABG surgery without use of cardiopulmonary bypass (off-pump procedures) and should reduce the cognitive decline associated with on-pump procedures.

Objective: To compare the effect of CABG surgery with (on-pump) and without (off-pump) cardiopulmonary bypass on cognitive outcome.

Design and setting: Randomized controlled trial conducted in the Netherlands of CABG surgery patients enrolled from March 1998 through August 2000, with 3- and 12-month follow-up.

Participants and intervention: Patients scheduled for their first CABG surgery (mean age, 61 years; n = 281) were randomly assigned to off-pump surgery (n = 142) or on-pump surgery (n = 139).

Main outcome measures: Cognitive outcome at 3 and 12 months, which was determined by psychologists (blinded for randomization) who administered 10 neuropsychological tests before and after surgery. Quality of life, stroke rate, and all-cause mortality at 3 and 12 months were secondary outcome measures.

Results: Cognitive outcome could be determined at 3 months in 248 patients. Cognitive decline occurred in 21% in the off-pump group and 29% in the on-pump group (relative risk [RR], 0.65; 95% confidence interval [CI], 0.36-1.16; P =.15). The overall standardized change score (ie, improvement of cognitive performance) was 0.19 in the off-pump vs 0.13 in the on-pump group (P =.03). At 12 months, cognitive decline occurred in 30.8% in the off-pump group and 33.6% in the on-pump group (RR, 0.88; 95% CI, 0.52-1.49; P =.69). The overall standardized change score was 0.19 in the off-pump vs 0.12 in the on-pump group (P =.09). No statistically significant differences were observed between the on-pump and off-pump groups in quality of life, stroke rate, or all-cause mortality at 3 and 12 months.

Conclusion: Patients who received their first CABG surgery without cardiopulmonary bypass had improved cognitive outcomes 3 months after the procedure, but the effects were limited and became negligible at 12 months.