Metabolic Syndrome Exacerbates Short-term Postoperative Cognitive Dysfunction in Patients Undergoing Cardiac Surgery: Results of a Pilot Study

ObjectiveThe authors tested the hypothesis that patients with metabolic syndrome are more likely to develop short-term cognitive dysfunction after cardiac surgery with cardiopulmonary bypass.DesignA prospective study.SettingVeterans Affairs medical center.ParticipantsFifty-six age- and education-balanced patients undergoing elective cardiac surgery with cardiopulmonary bypass (28 patients with and without metabolic syndrome in two separate groups) and 28 nonsurgical controls were enrolled.InterventionsNone.Measurements and Main ResultsRecent verbal and nonverbal memory and executive functions were assessed using a psychometric test battery before and 1 week after cardiac surgery or at 1-week intervals in nonsurgical controls. Neurocognitive scores under the baseline condition were at least 1 z score (1 standard deviation) worse in surgical patients with compared without metabolic syndrome in all 3 cognitive areas (nonverbal and verbal recent memory and executive functions). Neurocognitive performance further deteriorated after surgery by at least 1 z score on 3 tests in the verbal memory modality (Immediate and Delayed Story Recall and Delayed Word List Recall). Overall cognitive performance (composite z score) after surgery was significantly (p = 0.03) worse in metabolic syndrome patients compared with those who did not have the disorder.ConclusionsThe results indicate that short-term cognitive functions were more profoundly impaired in patients with metabolic syndrome undergoing cardiac surgery with cardiopulmonary bypass compared with their healthier counterparts.