Asymmetric cerebral embolic load and postoperative cognitive dysfunction in cardiac surgery

BACKGROUND: The aim of the study was to determine the effects of asymmetric cerebral embolic load on cognitive functions. METHODS: Thirty-six open heart surgery (OH) and 26 coronary artery bypass grafting (CABG) patients were evaluated by neuropsychological and transcranial Doppler tests. RESULTS: OH was associated with a significantly larger microembolic load in comparison to CABG. In OH patients, the microembolic load at the left middle cerebral artery correlated with a verbal memory decline, whereas the microembolic load at the right middle cerebral artery correlated with a nonverbal memory deficit. CABG patients also showed a postoperative verbal memory decline which correlated with cardiopulmonary bypass length but not with microembolic load. CONCLUSION: Massive microembolic load during OH induces specific cognitive impairment in accordance to the brain region to which they are delivered. In atherosclerotic patients, the left temporal region is especially prone to perioperative ischemia.