COGNITIVE OUTCOME AFTER CORONARY-ARTERY BYPASS - A ONE-YEAR PROSPECTIVE-STUDY

Background. Cognitive deficits have been reported in patients after co ronary artery bypass grafting, but the incidence of these deficits var ies widely. We studied prospectively the incidence of cognitive change and whether the changes persisted over time. Methods. Cognitive testi ng was done preoperatively and 1 month and 1 year postoperatively in 1 27 patients undergoing coronary artery bypass grafting. Tests were gro uped into eight cognitive domains. A change of 0.5 standard deviation or more at 1 month and 1 year from patient's preoperative Z score was the outcome measure. Results. We identified four main outcomes for eac h cognitive domain: no decline; decline and improvement; persistent de cline; and late decline. Only 12% of patients showed no decline across all domains tested; 82% to 90% of patients had no decline in visual m emory, psychomotor speed, motor speed, and executive function; 21% and 26% had decline and improvement in verbal memory and language; approx imately 10% had persistent decline in the domains of verbal memory, vi sual memory, attention, and visuoconstruction; and 24% had late declin e (between I month and 1 year) in visuoconstruction. Conclusions. This study establishes that the incidence of: cognitive decline varies acc ording to the cognitive domain studied and that some patients have per sistent and late cognitive changes in specific domains after coronary artery bypass grafting. (C) 1997 by The Society of Thoracic Surgeons.