Improved cognitive flexibility after aortic valve replacement surgery

Abstract

OBJECTIVES Aortic valve replacement (AVR) surgery is associated with potential risk to cerebral injury. On the other hand, improved cardiovascular functioning after the surgery may have positive impact on brain health. The aim of this preliminary study was to investigate the impact of AVR surgery on cognition, specifically on higher cognitive control functions, i.e. executive functions, that are typically implicated in cognitive decline due to vascular origin. METHODS Patients (n = 16) undergoing elective AVR surgery due to aortic stenosis were recruited and their cognitive performance was assessed using a computer-based Executive Reaction Time (RT) test. Testing was performed 1 day prior to AVR surgery and ∼3 months after the surgery. In addition, the Behavior Rating Inventory of Executive Function - Adult Version (BRIEF-A) was used to assess everyday challenges in executive functions and self-regulation. Patient's postoperative test results were compared with each patient's preoperative results to determine changes in executive functions. RESULTS Subjects' overall cognitive performance improved after AVR surgery. After surgery, patients responded in the Executive RT test more accurately with the same response speed (change from 297 to 298 ms). Their overall probability to commit an error (total errors) was reduced by 47%, reflecting improved executive functions in general (OR = 0.53, 95% CI = 0.46-0.59, error rate change from 44.8 to 28.0%). Furthermore, one key component of executive functions, inhibitory control, was improved after AVR surgery. This was seen in reduced probability of failing to withhold a response, i.e. making a commission error, by 89% (OR = 0.11, CI = 0.08-0.16, error rate change from 11.8 to 2.6%). The probability of missing a response was reduced by 48%, reflecting improved attention (OR = 0.52, 0.44-0.64, error rate change from 18.1 to 11.0%). No statistically significant differences in BRIEF-A scores were found. CONCLUSIONS There was a marked improvement in cognitive performance following AVR surgery, specifically in executive control functions indicating improved cognitive flexibility. Cognitive improvement, as opposed to the typical trajectory of cognitive decline in an elderly population with vascular disease, emphasizes the importance of these results and points to AVR surgery as having potential benefits on brain health in general. Clinical Trials identifier NCT01953068. https://www.clinicaltrials.gov/ct2/show/NCT01953068?term=NCT01953068&rank=1.