Metabolic syndrome exacerbates short-term postoperative cognitive dysfunction in patients undergoing cardiac surgery: results of a pilot study

Abstract

Objective: The authors tested the hypothesis that patients with metabolic syndrome are more likely to develop short-term cognitive dysfunction after cardiac surgery with cardiopulmonary bypass.

Design: A prospective study.

Setting: Veterans Affairs medical center.

Participants: Fifty-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.

Interventions: None.

Measurements and main results: Recent 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.

Conclusions: The 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.