The incidence of early neurological complications after on-pump cardiac surgery: a retrospective study

Background: Cardiac surgery with cardiopulmonary bypass (CPB) is associated with a significant risk for neurological complications. Reported incidence and risk factors for these complications vary significantly. Identifying risk factors could lead to preventive strategies to reduce complications and improve patient’s outcome. Objective: The study aims to assess the overall incidence and risk factors for severe early postoperative neurological complications after elective on-pump cardiac surgery. We specifically analyzed the incidence of stroke, global cerebral ischemia (GCI) and epilepsy in these patients. Methods: After getting approval from the Ethics Committee Research UZ/KU Leuven, on 14/12/2021 (s65871), we retrospectively evaluated data of 1080 adult patients after cardiac surgery with CPB between 06/2019 and 06/2021 at the University Hospitals Leuven. After exclusion of emergency procedures and patients who died before neurological evaluation, 977 patients remained for primary analysis. All data were collected from the electronic patient’s file. Primary objective was to identify the incidence of stroke, GCI and epilepsy. We defined stroke and GCI according to the American Stroke Association. Secondary endpoints were identifying independent risk-factors and assessing the impact of early neurological complications on mortality. Statistical analysis was performed using econometric and statistical modeling with python. We performed univariate logistic regression with Bonferonni correction and multivariable logistic regression with backwards elimination approach and p-value set to be <0.05. Results: The overall incidence of defined neurological complications after elective on-pump cardiac surgery at our institution was 3.17% (n=31) (stroke 2.35% (n=23), epilepsy 0.61% (n=6) and GCI 0.31% (n=3)). No statistically significant risk factors for these complications were found. In secondary analysis, patients with stroke and GCI had a higher risk of in-hospital mortality (Fisher’s exact test resulted in odds ratio 7.23 with p=0.005 and odds ratio 65.17 with p=0.003 respectively) Diabetes mellitus, preoperative atrial fibrillation, and endocarditis were also significantly related to in-hospital mortality. Conclusions: The incidence of early neurological complications after elective on-pump cardiac surgery at our institution was comparable to that reported in earlier studies. No independent risk factors for these neurological complications were found. The occurrence of stroke and GCI significantly increased in-hospital mortality which emphasizes the importance of these complications, with possible mortality benefit of early recognition and management of stroke.