Postoperative cognitive dysfunction and aortic atheroma.

BACKGROUND

The relationship of aortic atheroma to postoperative cognitive dysfunction (POCD), a common complication of coronary artery bypass graft surgery, has not been resolved. We undertook assessment of aortic atheroma using intraoperative ultrasonography and related the degree of aortic atheroma to POCD.

METHODS

Aortic atheroma was assessed using intraoperative transesophageal and epiaortic echocardiography in 311 patients who underwent coronary artery bypass graft surgery. Atheroma was graded from 0 (normal or minimal) to 3 (mobile or rough) in each of four quadrants of the proximal ascending to proximal descending thoracic aorta. Atheroma burden was defined as the atheroma score divided by the total possible score for that patient. Patients also completed a neuropsychological battery consisting of eight tests taken the week before surgery and at 1 week and 3 and 12 months afterward. Decreased cognitive function for each test was defined as an individual decrease of at least 1 standard deviation of the group baseline mean for that test, and POCD was defined as a decrease in two or more tests.

RESULTS

The atheroma burden (%) was greater in the patients with POCD. The difference was greatest at 1 week (10.4+/-14.7 versus 4.4+/-9.0, p=0.0002) and diminished progressively at 3 months (8.9+/-14.1 versus 5.4+/-10.1, p=0.06) and 12 months (6.6+/-12.0 versus 5.6+/-10.2, p=0.56). Multivariable analysis showed that atheroma burden strongly predicted POCD at 1 week.

CONCLUSIONS

Aortic atheroma burden predicts POCD at 1 week but has less impact on POCD as time progresses. Atheroma burden is highly correlated with age and may be a good predictor of early POCD.