Cognition 6 years after surgical or medical therapy for coronary artery disease

OBJECTIVE: The choice of coronary artery bypass grafting (CABG) as an intervention for coronary artery disease has been clouded by concerns about postoperative cognitive decline. Long-term cognitive decline after CABG has been reported, but without appropriate control subjects, it is not known whether this decline is specific to CABG or related to other factors such as cerebrovascular disease. METHODS: This prospective, observational study of patients with diagnosed coronary artery disease included 152 CABG and 92 nonsurgical cardiac comparison patients from one institution. The main outcome measure was within-patient change in cognitive performance for eight cognitive domains from baseline to 12- and 72-month follow-up. RESULTS: Mild late cognitive decline was observed for both study groups, but despite greater than 80% power to detect a 0.2 standard deviation difference, there were no statistically significant differences between the surgical and nonsurgical patients in the degree of change from 12 to 72 months for any cognitive domain. There was also no difference between groups in the degree of change from baseline to 72 months or in the number of patients with a Mini-Mental State Examination score in the clinically impaired range at 72 months. INTERPRETATION: Late cognitive decline does occur in patients who have undergone CABG surgery, but the degree of this decline does not differ from that observed in patients of similar age with coronary artery disease who have not undergone CABG. Therefore, late cognitive decline after CABG is not specific to the use of cardiopulmonary bypass.