Predictors of cognitive function in candidates for coronary artery bypass graft surgery CHRISTINE S. ERNEST, 1 PETER C. ELLIOTT, 1,2 BARBARA M. MURPHY, 1,3 MICHAEL R. LE GRANDE, 1 ALAN J. GOBLE, 1 ROSEMARY O. HIGGINS, 1 MARIAN U.C. WORCESTER, 1,4 and JAMES TATOULIS 5 1 Heart Research Centre, Melbourne, Victoria, Australia 2 Australian Centre for Posttraumatic Mental Health, The University of Melbourne, Victoria, Australia 3 Department of Psychiatry, The University of Melbourne, Victoria, Australia 4 Department of Psychology, The University of Melbourne, Victoria, Australia 5 Department of Cardiothoracic Surgery, The Royal Melbourne Hospital, Victoria, Australia (Received April 27, 2006; Final Revision September 12, 2006; Accepted September 13, 2006) Abstract Candidates for coronary artery bypass graft surgery have been found to exhibit reduced cognitive function prior to surgery. However, little is known regarding the factors that are associated with pre-bypass cognitive function. A battery of neuropsychological tests was administered to a group of patients listed for bypass surgery ( n 5 109). Medical, sociodemographic and emotional predictors of cognitive function were investigated using structural equation modeling. Medical factors, namely history of hypertension and low ejection fraction, significantly predicted reduced cognitive function, as did several sociodemographic characteristics, namely older age, less education, non-English speaking background, manual occupation, and male gender. One emotional variable, confusion and bewilderment, was also a significant predictor whereas anxiety and depression were not. When significant predictors from the three sets of variables were included in a combined model, three of the five sociodemographic characteristics, namely age, non-English speaking background and occupation, and the two medical factors remained significant. Apart from sociodemographic characteristics, medical factors such as a history of hypertension and low ejection fraction significantly predicted reduced cognitive function in bypass candidates prior to surgery. ( JINS, 2007, 13, 257–266.) Keywords: Cardiac patients, Coronary heart disease, Pre-operative cognition, Cognitive impairment, Risk factors, Cognitive manifestation INTRODUCTION Reduced cognitive function has been reported in candidates for coronary artery bypass graft surgery (CABGS) in pre- vious studies (Ernest, Murphy et al., 2006; Millar et al., 2001; K.P. Rankin et al., 2003; Rosengart et al., 2005; Vingerhoets et al., 1997). Because patients with cognitive impairment pre-bypass seem to be at a higher risk for devel- oping post-operative cognitive impairment (Ho et al., 2004; Millar et al., 2001), it is important to identify factors that contribute to this reduced cognitive function. However, only a few studies have examined predictors of pre-bypass cog- nitive function (Tsushima et al., 2005; Vingerhoets et al., 1997). Vingerhoets and colleagues (1997) explored medi- cal and sociodemographic factors in valve and CABGS patients, whereas Tsushima and colleagues (2005) exam- ined sociodemographic and emotional characteristics in CABGS patients. To our knowledge, no study has investi- gated all three categories of potential predictors of reduced cognitive function in CABGS candidates, particularly the relative strengths of significant predictors. The cardiovascular disease process itself has been impli- cated as a causative factor in bypass candidates’ reduced cognitive performances (Selnes et al., 2003; Vingerhoets et al., 1997). In recent reviews, reduced cognitive function has been found to be associated with chronic hypertension, reduced ejection fraction, impaired left ventricular func- tion, atherosclerosis, cardiac arrhythmia, acute myocardial infarction and cardiac arrest (Byrne, 1994; Elias et al., 2001; Moser et al., 1999; Waldstein & Katzel, 2001; Waldstein Correspondence and reprint requests to: Dr. Christine Ernest, Heart Research Centre, Box 2137 Post Office, The Royal Melbourne Hospital, Victoria 3050, Australia. E-mail: christine.ernest@heartresearchcentre.org Journal of the International Neuropsychological Society (2007), 13, 257–266. Copyright © 2007 INS. Published by Cambridge University Press. Printed in the USA. DOI: 10.10170S1355617707070282 257