Early natural course of transient encephalopathy after coronary artery bypass grafting

A decline of neuropsychological performance is an unwanted side effect of coronary artery bypass grafting (CABG) with extracorporeal circulation. There is little data on the neuropsychological changes during the first 2 wks after CABG.

In this prospective observational study at our university medical center, a group of 67 patients who underwent routine CABG was selected for absence of comorbidity (such as carotid stenosis, previous stroke, dementia, and advanced general medical disorders) and examined. In this selected group of patients, no focal deficit was seen throughout the study. A total of 20 hospitalized patients with different types of peripheral neuropathy and free from drugs interfering with cognition served as a control group for the practice effects of the neuropsychological testing.

Seven standard tests covering different neuropsychological domains were used as a composite battery. Examinations took place before surgery and serially at days 3, 6, and 9 after CABG; general neurologic examination was done every day, including the first postoperative day. We observed a definite decline in all tests at day 3 (p < .01) and progressive recovery thereafter up to or even beyond preoperative values within 9 days (p < .01). Transient depression as indicated by self-rated scores occurred in some patients.

We observed a uniform, but transient, deterioration in performance on a battery of frequently repeated standardized neuropsychological tests early after CABG. Our data on the early natural course may help to better evaluate treatment efforts aimed at preventing or reducing after-surgery neuropsychological alterations.