P ostoperative but not preoperative depression is associated with cognitive impairment after cardiac surgery: exploratory analysis of data from a randomized trial

Background: In this study we hypothesize that depression is associated with perioperative neurocognitive dysfunction and altered quality of life one month after surgery. Methods: Data were obtained as part of a study evaluating cerebral autoregulation monitoring for targeting arterial pressure during cardiopulmonary bypass. Neuropsychological testing was performed before surgery and one month postoperatively. Testing included the Beck Depression Inventory, a depression symptoms questionnaire (0–63 scale), as well as anxiety and quality of life assessments. Depression was defined as a Beck Depression Inventory score > 13. Results: Beck Depression data were available from 320 patients of whom cognitive domain endpoints were available from 88–98% at baseline and 69–79% after surgery. This range in end-points data was due to variability in the availability of each neuropsychological test results between patients. Depression was present in 50 (15.6%) patients before surgery and in 43 (13.4%) after surgery. Baseline depression was not associated with postoperative domain-specific neurocognitive function compared with non-depressed patients. Those with depression one month after surgery, though, had poorer performance on tests of attention (p = 0.017), memory (p = 0.049), verbal fluency (p = 0.010), processing speed (p = 0.017), and fine motor speed (p = 0.014). Postoperative neurocognitive dysfunction as a composite outcome occurred in 33.3% versus 14.5% of patients with and without postoperative depression (p = 0.040). Baseline depression was associated with higher anxiety and lower self-ratings on several quality of life domains, these measures were generally more adversely affected by depression one month after surgery. Conclusions: The results of this exploratory analysis suggests that preoperative depression is not associated with perioperative neurocognitive dysfunction, but depression after cardiac surgery may be associated with impairment in in several cognitive domains, a higher frequency of the composite neurocognitive outcome, and altered quality of life. Trial Registration: www.clinicaltrials.gov, NCT00981474 (parent study).