European Journal of Cardio-Thoracic Surgery, Vol 11, 424-431, Copyright © 1997 by European Association for Cardio-thoracic Surgery
Short-term and long-term neuropsychological consequences of cardiac surgery with extracorporeal circulation
G Vingerhoets, G Van Nooten, F Vermassen, G De Soete and C Jannes
Department of Psychiatry and Neuropsychology, University Hospital Gent, Belgium.
OBJECTIVE: Cognitive dysfunction after extracorporeal circulation is a
major continuing problem in modern cardiac surgery. We designed this
prospective study to update the incidence of postoperative
neuropsychological changes after routine cardiopulmonary bypass (CPB) and
to identify perioperative variables associated with these complications.
METHODS: We assessed the patients with a comprehensive neuropsychological
test battery 1 day before, 7 days after (n = 109) and 6 months after (n =
91) cardiopulmonary bypass. We used patients undergoing major vascular or
thoracic surgery as a surgical control group (n = 20). RESULTS: Repeated
measures multivariate analysis of variance (using surgical group as a
between-subjects factor) on the group data revealed significant changes
early after surgery compared with the preoperative performance (P = 0.001).
The early changes are characterized by a significant decrease of visual
attention and verbal memory performance (univariate F-tests, always P <
0.05). Cardiac patients showing cognitive impairment after cardiac surgery
had lower preoperative ejection fractions (P = 0.014) and a more
complicated medical history (P = 0.046). At 6-month follow-up, the patients
performed significantly better than before surgery (P < 0.001). CPB
patients showing persistent cognitive impairment at follow-up were
significantly older at the time of surgery (P = 0.005). Individual
comparisons revealed that 45% of the patients undergoing CPB showed
evidence of cognitive impairment soon after surgery. In 12% of the
patients, the cognitive sequelae persisted at follow-up. Both group data
and individual incidence rates revealed neither significant pre- post
differences between the surgical groups nor a time-by-group interaction
effect. Variables directly associated with CPB were not significantly
associated with the occurrence of cognitive impairment after surgery.
CONCLUSIONS: We conclude that an important proportion of the cognitive
impairment after cardiac surgery is likely to be due to nonspecific effects
of surgery.