Postoperative cognitive decline (POCD) is one of the most common complications after cardiac surgery. It is characterized by impaired memory, attention, and executive functions and can have long-term consequences. The goal of this observational study was to investigate the mechanisms of cognitive decline after cardiac surgery and potential biomarkers that could aid in the diagnosis, prevention, and treatment of POCD. The investigators focused on the role of microRNAs (miRNAs) and systemic inflammatory response to surgery, extracorporeal circulation, and anesthesia as potential factors involved in the development of the neuroinflammatory response and subsequent POCD. The main question this study aims to answer is whether perioperative miRNA 151-5p expression is associated with POCD after surgery. The second aim is to examine the association between miRNA-151-5p and systemic inflammation. The investigators measured circulating miRNA-151-5p levels and plasma levels of inflammatory biomarkers in patients undergoing surgical myocardial revascularization. To assess cognitive function, participants completed the Montreal Cognitive Assessment (MoCA Test). Changes in the measured values of miRNA-151-5p expression and inflammatory markers, as well as changes in cognitive status after surgery, were assessed in relation to the preoperative state.
Surgical myocardial revascularization is a procedure used in patients with ischemic heart disease to bypass atherosclerotic narrowings or blockages of the coronary arteries using an arterial or venous graft (Coronary Artery Bypass Grafting - CABG). One of the most common complications after cardiac surgery is postoperative cognitive decline (POCD). It is characterized by impaired memory, attention, and executive functions and can have long-term consequences, such as delayed physical therapy and mobilization, prolonged stay in the intensive care unit and hospital, more frequent discharge to nursing homes, reduced quality of life, and increased mortality. The causes of POCD are multifactorial. The systemic inflammatory response to surgery, extracorporeal circulation, and anesthesia is considered a factor in the development of the neuroinflammatory response and subsequent POCD. Neuroinflammation can cause dysfunction or death of brain cells and damage to the blood-brain barrier, leading to an increase in the level of biochemical markers of brain injury in the blood. Studies indicate that numerous microRNAs (miRNAs) play a role in controlling the inflammatory response. MiRNAs are small, endogenous, non-coding RNA molecules, typically 18-25 nucleotides long, that regulate gene expression at the post-transcriptional level. They are central mediators of cellular proliferation, differentiation, and apoptosis. MiRNA levels in tissues and peripheral blood are similar, and circulating miRNAs are stable and suitable for measurement. Specific miRNAs (miRNA 151-5p, 505, 499, 625, and others) may be potential early biomarkers of brain damage after a mild traumatic brain injury. Anesthesia and surgery also, through complex mechanisms, can cause changes in brain cells that can lead to the release of specific miRNAs, and these miRNAs can be detected in blood and various biological fluids. Hypothesis: Higher levels of perioperative miRNA-151-5p expression are associated with the systemic inflammatory response and with the development of POCD. Aim of this study is: 1. To investigate the association between miRNA-151-5p expression levels and biochemical parameters of systemic inflammation, as well as the association of both with cognitive status in patient undergoing CABG surgery. 2. To investigate the association between patients' demographic and clinical characteristics and miRNA-151-5p expression levels, the level of biochemical parameters of systemic inflammation, and patients' cognitive status. Research plan: The research was carried out at the Clinical Hospital Centre Osijek. Respecting the inclusion and exclusion criteria for participation in the study, the research included patients aged 65 to 80 years who, according to the American Society of Anesthesiologists (ASA) classification, are classified into groups III and IV, and who are undergoing CABG surgery with the use of extracorporeal circulation. Surgeries were performed according to the standard protocol for balanced anesthesia, cardiac surgery, and extracorporeal circulation. All participants underwent the same anesthetic procedure and anesthesia based on midazolam, propofol, sufentanyl, rocuronium and sevoflurane. The depth of anesthesia was monitored using Patient State Index (PSI). All surgeries were performed using extracorporeal circulation with the maintenance of normothermia (36 °C). Blood samples for determination of levels of cholinesterase, interleukin-6, protein S100B, miRNA-151-5p expression and routine laboratory parameters (complete blood count, levels of troponin I, C-reactive protein, procalcitonin, glucose, urea, creatinine, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, total bilirubin, albumin, electrolytes, lactate, coagulation tests, and arterial blood gas analysis) were taken at three time points: before surgery prior to induction of anesthesia, immediately after the procedure upon admission to the intensive care unit, and 48 hours after the surgical procedure. Cognitive function testing was performed the day before surgery and postoperatively, once daily every day until the 6th postoperative day. The investigators used a validated scoring scale for assessing cognitive functions, the Montreal Cognitive Assessment - MoCA Test. Demographic and clinical data were recorded for all subjects. Subjects were followed up 7 days.
Study Type
OBSERVATIONAL
Enrollment
48
University Hospital Osijek
Osijek, Croatia
Perioperative changes in microRNA 151-5p expression.
MicroRNA-151-5p expression levels will be measured in tree time points: preoperative before induction of anaesthesia, postoperative within 2 hours of Intensive Care Unit (ICU) admission and 48 hours after admission to the ICU. Levels of microRNA expression will be calculated relative to reference microRNA-16-5p using 2-∆∆cT method.
Time frame: Preoperative, within 2 hours of ICU admission, 48 hours after ICU admission
Perioperative changes in cognitive function measured by Montreal Cognitive Assessment (MoCA Test).
Cognitive function will be assessed in all patients at enrollment one day before surgery, and daily for the following six postoperative days using the Montreal Cognitive Assessment (MoCA test). Montreal Cognitive Assessment scale: minimum score is 0 and maximum score is 30 points, a score of 26 or above is considered normal, while scores below this may indicate cognitive impairment. A score of 18-25 suggests mild cognitive impairment, 10-17 suggests moderate impairment, and a score 0-9 suggests severe impairment.
Time frame: 1 day before surgery and once daily postoperatively, up to the 6th postoperative day.
Perioperative changes in levels of white blood cells.
Levels of white blood cells will be measured in tree time points: preoperative before induction of anaesthesia, postoperative within 2 hours of Intensive Care Unit (ICU) admission and 48 hours after admission to the ICU.
Time frame: Preoperative, within 2 hours of ICU admission, 48 hours after ICU admission.
Perioperative changes in levels of C-reactive protein.
Levels of C-reactive protein will be measured in tree time points: preoperative before induction of anaesthesia, postoperative within 2 hours of Intensive Care Unit (ICU) admission and 48 hours after admission to the ICU.
Time frame: Preoperative, within 2 hours of ICU admission, 48 hours after ICU admission
Perioperative changes in levels of procalcitonin.
Levels of procalcitonin will be measured in tree time points: preoperative before induction of anaesthesia, postoperative within 2 hours of Intensive Care Unit (ICU) admission and 48 hours after admission to the ICU.
Time frame: Preoperative, within 2 hours of ICU admission, 48 hours after ICU admission
Perioperative changes in levels of interleukin-6.
Levels of interleukin-6 will be measured in tree time points: preoperative before induction of anaesthesia, postoperative within 2 hours of Intensive Care Unit (ICU) admission and 48 hours after admission to the ICU.
Time frame: Preoperative, within 2 hours of ICU admission, 48 hours after ICU admission
Perioperative changes in levels of cholinesterase.
Levels of cholinesterase will be measured in tree time points: preoperative before induction of anaesthesia, postoperative within 2 hours of Intensive Care Unit (ICU) admission and 48 hours after admission to the ICU.
Time frame: Preoperative, within 2 hours of ICU admission, 48 hours after ICU admission
Perioperative changes in levels of protein S-100B.
Levels of protein S-100B will be measured in tree time points: preoperative before induction of anaesthesia, postoperative within 2 hours of Intensive Care Unit (ICU) admission and 48 hours after admission to the ICU.
Time frame: Preoperative, within 2 hours of ICU admission, 48 hours after ICU admission
Patient demographic data.
Patient demographic data: age, gender, education, and previous medical history will be recorded and correlated with microRNA expression levels, inflammatory biomarkers and the Montreal Cognitive Assessment (MoCA test) scores. Montreal Cognitive Assessment scale: minimum score is 0 and maximum score is 30 points, a score of 26 or above is considered normal, while scores below this may indicate cognitive impairment. A score of 18-25 suggests mild cognitive impairment, 10-17 suggests moderate impairment, and a score 0-9 suggests severe impairment.
Time frame: From enrollment to the end of cognitive testing at 6th postoperative day.
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