Magnetic resonance imaging and P300 (event-related auditory evoked potentials) in the assessment of postoperative cerebral injury following coronary artery bypass graft surgery

Cerebral injury following coronary artery bypass grafting (CABG) surgery was investigated with magnetic resonance imaging (MRI) and P300, a long-latency endogenous evoked potential associated with psychological processing of stimulus information. Twelve patients were studied before and after surgery. Prior to surgery, MRI abnormalities were found in all but one patient. After surgery, five patients had new abnormalities, mainly deep white-matter lesions (DWML). Postoperative P300 latency was significantly increased in six patients. P300 topographical distribution showed a shift from predominantly posterior cerebral regions to frontal regions in most patients. Postoperative P300 and MRI deficits were found in three of the five patients. One of the patients with marked MRI change (DWML in caudate nucleus) did not show P300 deficit.