The Practical Use of White Cell Inflammatory Biomarkers in Prediction of Postoperative Delirium after Cardiac Surgery

Abstract

Introduction: Postoperative delirium (POD) is associated with unfavorable outcomes. It may result from neuroinflammation and oxidative stress. The aim of this study was to evaluate the role of routinely available inflammatory markers derived from white blood cell count (WBC), for prognostic value in diagnosing delirium after cardiac surgery. Methods: We performed an analysis of data collected from patients undergoing planned coronary artery bypass grafting (CABG). Differential WBC and CRP (C-reactive protein) concentration were evaluated preoperatively (T0) and postoperatively at day 1 (T1), 3 (T3), 5 (T5) after CABG. Differences in neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and platelet-to-WBC ratio (PWR) between patients with (Del +) and without delirium (Del −) were evaluated. Patients were screened using CAM-ICU. Results: We included 968 patients in the study. Incidence of delirium was 13.3%. In the group with POD, the majority of patients were men (87/129, 67.44%), and the mean age was 72 years. Preoperative WBC (8.21 ± 3.04 G/l vs. 7.55 ± 1.86 G/l, p = 0.029) were higher and mean platelet count was lower (217.7 ± 69.07 G/l vs. 227.44 ± 59.31 G/l, p = 0.031) in patients with POD. Lower pre-operative PLR values (109.87 ± 46.38 vs. 120.36 ± 52.98, p = 0.026) and PWR values (27.69 ± 7.50 vs. 31.32 ± 9.88 p < 0.001) were found in patients with POD. Association was strongest for PWR and remained significant at T1 (p < 0.001), T3 (p < 0.001) and T5 (p < 0.001). Basing on coefficients of logistic regression a model for optimal prediction of POD was calculated: CARDEL Index (CARdiac DELirium Index) = 0.108 × Age + 0.341 × HBA1C − 0.049 × PWR with AUC of 0.742 (p < 0.001). Conclusions: The results of this study show that lower pre-operative levels of PLR and PWR were associated with POD after cardiac surgery. Pre-operative PWR showed strongest correlation with POD and may be a potential new biomarker associated with postoperative delirium. CARDEL prognosis index composed of age, HbA1c and PWR is good at predicting development of delirium after CABG.

The Usefulness of Inflammation-based Prognostic Scores for the Prediction of Postoperative Mortality in Patients Who Underwent Intestinal Resection for Acute Intestinal Ischemia

“…An accurate prediction of outcome after an emergency surgery would better assist clinicians when discussing mortality with the patients and their families and guiding difficult treatment decisions [5]. The physiological immune response of circulating leucocytes to various stressful events is often characterized by an increase in neutrophil count and a decline in lymphocyte count along with a decrease in platelet count [6]. The NLR and PLR are simple, readily available laboratory variables.…”

Current Evidence Regarding Biomarkers Used to Aid Postoperative Delirium Diagnosis in the Field of Cardiac Surgery—Review

“…The search for an ideal delirium marker is a complex process as many confounding factors account for delirious state postoperatively [ 61 ]. It is much more probable that this will be based on the identification of a panel of biomarkers in order to make an accurate and quick diagnosis [ 51 , 62 ].…”

“…This is consistent with the data reported by Çinar et al that CRP, although elevated, cannot be considered as an independent risk factor in the development of POD [ 98 ]. On the other hand, a study, including the CRP levels performed by Kotfis et al, showed a correlation between increased CRP levels and delirium [ 62 ].…”

“…In a retrospective cohort analysis on a total group of 1904 patients, Kotfis et al studied NLR, PLR, and PWR with CRP for the establishment of an easy-to-obtain predictor of delirium in cardiac surgery patients [ 62 ]. The study showed that in the delirium group, which was over 13% of the total study population, most of the delirious patients were older men with comorbidities, such as hypertension, extracardiac atherosclerosis, and chronic renal failure, and this group experienced a long time of postoperative mechanical ventilation with significantly higher mortality both at 30 days and 1 year after surgery.…”

“…In order to obtain an inexpensive, less time-consuming, and possible to use in everyday clinical practice marker of delirium, Kotfis et al used laboratory data together with an objective pre-operative examination to produce a CARDEL index, which is based on the function of age, glycosylated hemoglobin (HbA1c), and PWR. The analysis showed that the CARDEL index was more accurate in predicting the development of delirium after CABG than any of these factors alone [ 62 ]. White cells-derived biomarkers are summarized in Table 3 .…”