Magnetic Resonance Imaging and Neuropsychological Changes After Coronary Artery Bypass Graft Surgery: Preliminary findings

Abstract

Cerebral morbidity is a problem after cardiac surgery. Although neuropsychological tests and imaging techniques have been applied to cardiac patients, the relationship between them has not been considered. In the preliminary investigation, we studied 15 patients (11 male, mean age 59 years) having coronary artery bypass graft (CABG) surgery. Before surgery, patients had magnetic resonance (MR) imaging and neuropsychological assessment with a battery of 10 tests. During surgery, cardiopulmonary bypass was maintained at 28 degrees C with a flow rate of 2.4 L/m2/min-1 and at a mean arterial pressure of 50-70 mm Hg. Bubble or membrane oxygenators with in-line filters were used. Arterial blood gases were maintained using a pH-stat protocol. Fourteen of the 15 patients showed MR abnormalities before surgery. One week after surgery, four patients had additional MR changes. Six patients had significant postoperative neuropsychological deficit in memory (verbal and nonverbal) and attention. The four patients with new MR abnormalities all had significant neuropsychological deficit. In addition to corroborating previous observations that a high proportion of patients undergoing elective CABG have MR abnormalities before surgery, these preliminary data suggest a promising concordance between structural brain changes and cerebral function after CABG.