Preexisting cognitive impairment in patients scheduled for elective coronary artery bypass graft surgery.
BACKGROUND
An accurate assessment of the prevalence of cognitive impairment in patients scheduled for coronary artery bypass graft (CABG) surgery is necessary if valid assumptions regarding cognitive change are to be made. Such an assessment requires the use of a healthy control group free of cardiovascular disease.


METHODS
In a retrospective observational study, 349 patients scheduled for CABG surgery underwent neuropsychological testing. We compared the results with those from a group of 170 healthy controls without cardiovascular disease and containing more female patients who were matched for age and IQ score. Cognitive impairment was defined as test scores > or =2 sd less than the controls on two or more of the seven tests.


RESULTS
The CABG surgery patients performed significantly worse than the control group on all tests except the Grooved Pegboard test (nondominant). When analyzed by group, performance on the verbal learning test was the most impaired. Cognitive impairment was present in 122 (35%) of CABG surgery patients before their procedure. Prior myocardial infarction, age, and IQ were independent predictors of cognitive impairment.


CONCLUSIONS
Cognitive impairment is prevalent in patients presenting for CABG surgery. Impaired cognition before surgery must be considered when assessing the effects of CABG surgery on cognitive performance.
Silbert
Brendan S
BS
Department of Anaesthesia, Centre for Anaesthesia and Cognitive Function, St. Vincent's Hospital, Melbourne, Australia. brendan.silbert@svhm.org.au
Scott
David A
DA
Evered
Lisbeth A
LA
Lewis
Matthew S
MS
Maruff
Paul T
PT
D000368:Aged; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology*; D001026:Coronary Artery Bypass / Q000523:psychology; D017558:Elective Surgical Procedures / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011300:Preoperative Care / Q000379:methods; D012189:Retrospective Studies