Impact of the intensity of microemboli on neurocognitive outcome following cardiopulmonary bypass

Abstract

Background: This study aimed to determine whether there was any association between the intensity of intraoperative gaseous microembolic signals (GME), neuropsychological testing and clinical outcome in high-risk patients undergoing coronary artery surgery (CABG). Methods: Over a 6-month period, GME activity was monitored in 102 Euroscore 6+ patients during cardiopulmonary bypass (CPB) with a conventional 32-micron arterial filter by non-invasive, real-time ultrasonic device. Cognitive tests; line bisection, the Stroop test, finger tapping, and the Rey Auditory Verbal Learning Test were performed at baseline, postoperative one week and postoperative one month. Results: The distribution of GME activity showed that there were three groups of patients: >500 total emboli (n = 38); 250 to 500 emboli (n = 30) and <250 emboli (n = 34) at a detection level of 2% of the circuit diameter on the arterial side. Line bisection, the Stroop test and finger tapping were impaired significantly in >500 emboli patients versus control (<250 emboli) in postoperative week one, but resolved in one month. Conclusions: Correlation between intraoperative GME intensity and neurocognitive tests suggests that the level of GME might have a role in determining the psychological outcome after CABG with CPB.