Neurocognitive and neuroanatomic changes after off-pump versus on-pump coronary artery bypass grafting: long-term follow-up of a randomized trial

Abstract

Objective: It is unknown whether avoidance of cardiopulmonary bypass during coronary artery bypass grafting affects cerebral injury or long-term neuropsychological function.

Methods: Two hundred unselected patients were randomized to off-pump coronary artery bypass or on-pump coronary artery bypass grafting between March 2000 and August 2001. One hundred sixty-eight patients had early postoperative brain magnetic resonance imaging. Eighty-seven returned after a mean of 7.5 years of follow-up; 67 had repeat magnetic resonance imaging, and 76 had neuropsychological testing.

Results: There were 26 deaths among patients undergoing off-pump coronary artery bypass and 31 among patients undergoing cardiopulmonary bypass as of March 2009. Seventy-six patients (41 undergoing cardiopulmonary bypass and 35 undergoing off-pump coronary artery bypass) had neuropsychological testing at late follow-up. Groups were similar in age, sex, depression, and IQ. Patients undergoing off-pump coronary artery bypass showed better attention, performing better at tracking and mentally manipulating information (P =.011). Patients undergoing off-pump coronary artery bypass demonstrated better cognitive reasoning and made fewer errors in reasoning (P = .05); they also showed a trend toward better verbal learning (P = .064). There were no domains in which patients undergoing cardiopulmonary bypass outperformed those undergoing off-pump coronary artery bypass. Early magnetic resonance imaging in 168 patients showed no significant differences between groups in temporal or frontal lobe atrophy, subcortical white matter lesions, or acute infarctions. There were no significant differences between groups in atrophy over time or new subcortical white matter lesions or infarctions. Acute perioperative cerebral infarctions were more common and atrophy more progressive during follow-up among diabetic than nondiabetic patients.

Conclusions: After a mean of 7.5 years of follow-up, patients undergoing off-pump coronary artery bypass performed better than those undergoing cardiopulmonary bypass in several neuropsychological domains; these differences were small and of uncertain clinical importance. Early brain magnetic resonance imaging showed no significant differences in acute cerebral infarctions between the off-pump coronary artery bypass and cardiopulmonary bypass groups.