Early postoperative cognitive dysfunction and blood pressure during coronary artery bypass graft operation.

OBJECTIVE To determine the relationship between change in blood pressure during coronary artery bypass graft operations and early cognitive dysfunction. DESIGN Cohort study. SETTING Quaternary care facility. Patients Fifteen patients undergoing coronary artery bypass graft operations who were at high risk for postoperative stroke. Preoperative and intraoperative mean arterial pressures (MAPs) were measured in all patients. Intervention A subset of patients underwent preoperative and postoperative magnetic resonance imaging. Main Outcome Measure Change in cognitive performance, using the Mini-Mental State Examination and other simple cognitive tests. RESULTS A drop in MAP (preoperatively to intraoperatively) predicted a decrease in Mini-Mental State Examination score. When change in MAP was dichotomized (after excluding an outlier), subjects with a small decrease improved on the Mini-Mental State Examination by 1 point, whereas those with a large drop in MAP worsened by 1.4 points (P = .04). CONCLUSION A drop in MAP from a preoperative baseline may put patients at risk for early cognitive dysfunction after a coronary artery bypass graft operation.