Atherosclerosis is associated with delirium after coronary artery bypass graft surgery

OBJECTIVES: To investigate whether atherosclerosis of the ascending aorta, internal carotid arteries, and coronary arteries is predictive of postoperative delirium in subjects undergoing coronary artery bypass graft (CABG) surgery. DESIGN: Prospective cohort study. SETTING: Boston Veterans Affairs Healthcare System. PARTICIPANTS: Thirty-six male veterans undergoing primary CABG surgery. MEASUREMENTS: Subjects underwent Duplex ultrasound to assess stenosis in the internal carotid arteries. Information on the ascending aortic plaque, as assessed by transesophageal echocardiogram, and the number of coronary vessels bypassed was collected. To create an atherosclerosis score, the number of atherosclerotic areas was added. A validated delirium battery was administered to the subjects preoperatively and on postoperative Days 2 and 5. RESULTS: Fifteen subjects (41.7%) developed delirium postoperatively. In bivariate analysis, carotid stenosis of 50% or more (relative risk (RR)=3.5, 95% confidence interval (CI)=1.5-8.1) and moderate-severe ascending aortic plaque (RR=2.9, 95% CI=1.0-8.5) were significantly associated with the development of delirium. There was a trend toward a significant association for three or more vessels bypassed (RR=9.6, 95% CI=0.6-145.3). After controlling for age, baseline cognition, and medical comorbidity, the atherosclerosis score was significantly associated with postoperative delirium (adjusted RR=2.7, 95% CI=1.1-6.8). CONCLUSION: In this preliminary report, atherosclerosis in the carotid arteries, aorta, and coronary circulation is associated with the development of delirium after CABG surgery. Further investigation into atherosclerosis as a risk factor for delirium is warranted.