Potentials of Acetylcholinesterase and Butyrylcholinesterase Alterations in On-Pump Coronary Artery Bypass Surgery in Postoperative Delirium: An Observational Trial

Abstract

Cardiac surgery is regularly associated with postoperative delirium (POD), affected by neuro-inflammation and changes in cholinergic activity. Therefore, this prospective observational study aimed to evaluate whether pre- and perioperative changes in blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity were associated with POD development in patients undergoing isolated elective coronary artery bypass graft (CABG) surgery. It included 93 patients. Pre- and postoperative blood AChE and BChE activities were measured with photometric rapid-point-of-care-testing. The Intensive Care Delirium Screening Checklist and the Confusion Assessment Method for the Intensive Care Unit were used to screen patients for POD. POD developed in 20 patients (21.5%), who were older (p = 0.003), had higher EuroSCOREs (p ≤ 0.001), and had longer intensive care unit stays (p < 0.001). On postoperative day one, BChE activity decreased from preoperative values more in patients with (31.9%) than without (23.7%) POD (group difference p = 0.002). Applying a cutoff of ≥32.0% for BChE activity changes, receiver operating characteristic analysis demonstrated a moderate prediction capability for POD (area under the curve = 0.72, p = 0.002). The risk of developing POD was 4.31 times higher with a BChE activity change of ≥32.0% (p = 0.010). Monitoring the pre- to postoperative reduction in BChE activity might be a clinically practicable biomarker for detecting patients at risk of developing POD after CABG surgery.

Keywords: cardiac surgery; cardiopulmonary bypass; intensive care; postoperative care; postoperative delirium; preoperative patient evaluation and improvement.

Figure 1

Chart demonstrating the recorded points of the used screening tools at the study time points. Abbreviations: CAM-ICU, confusion assessment method–intensive care unit; ICDSC, intensive care delirium screening checklist; POD, postoperative delirium.

Figure 2

Butyrylcholinesterase (BChE) (A) and acetylcholinesterase (AChE) activity (B) on postoperative day one shown as a percentage of baseline activity measured before surgery. Key: **, p = 0.002.

Figure 3

BChE (A) and AChE (B) activity preoperative and on postoperative days 1–7.

Figure 4

Receiver operating characteristic curve for BChE activity on postoperative day one as a predictor of POD. Key: *, optimal cut-off point that optimizes the differentiating ability when equal weight is given to sensitivity and specificity.