Post-Coronary Artery Bypass Grafting Cognitive Decline: Risk Modification And Implications For Screening In Low-Risk Population

Abstract

Background — Postoperative cognitive dysfunction (POCD) is an important complication of coronary artery bypass grafting (CABG). Large amount of data points to the problem of POCD in patients with high surgical risk of CABG. Low-risk patients are not safe from these complications either. Assessment of the severity, duration of POCD, degree of recovery and risk factors in off- and on-pump patients with stable coronary artery disease is crucial in minimization of the POCD risk in patients with low surgical risk. Objective — to analyze incidence, severity, reversibility and risk factors of POCD in patients undergoing elective low-risk CABG. Methods and Results — The retrospective cohort study included 79 patients who underwent on-pump (N=44) or off-pump (N=35) elective CABG with low surgical risk (mean EuroSCORE II death risk 1.08±0.71%), with observation period of 6 months. Pre-CABG markers of cognitive impairment were found in 50% of patients, with 44% of patients demonstrating POCD. Patients who underwent off-pump CABG demonstrated more pronounced decline in MoCA score compared to on-pump (-3.9±2.0 vs. -2.2±2.0 at 8 days point, p=0.018), with regress to pre-CABG results after 3 weeks. Baseline MoCA score <25 was found to be a predictor for more pronounced cognitive decline at 8 days point. MMSE demonstrated less predictive value compared to MoCA. Conclusion — POCD risk differs in off-pump and on-pump CABG cohorts, with significantly higher prevalence in the former group, whether assessed using MMSE or MoCA tests. Differences are observed within 3 weeks post-CABG. Pre-CABG MoCA score <25 is associated with more pronounced POCD in low-risk elective CABG cohort.