Delirium in Elderly Undergoing Cardiac Surgery and the Significance of CholinEsterase Activity

Study Overview
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Brief Summary
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The purpose of this study is to assess the association between the point-of-care (POC) measured ChE activity (Acetylcholinesterase (ChE) + Buturylcholinesterase (ChE)) and postoperative delirium in elderly patients undergoing cardiac surgery. Furthermore the investigators aim to identify factors, which influence the baseline levels and the time course of ChE activity.

Detailed Description
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Cardiac surgery in elderly patients is associated with serious complications, like increased morbidity, mortality and postoperative delirium with further hazardous consequences. The incidence of postoperative delirium in elderly is reported with a range from 36.6% - 54.9%. The pathophysiology of delirium is complex and the interaction of the cholinergic system and inflammation reaction is a relevant precipitant factor. It was suggested that there is a strong association between the perioperative plasma ChE activity and the inflammatory response in patients developing delirium. Patients showed a significant reduction of the total ChE activity after orthopaedic surgery, with significant lower pre- and postoperative values of AChE and BuChE and increased inflammatory response in patients developing postoperative delirium. It remains unclear if these results are applicable to other patient populations and which factors have influenced the low preoperative ChE levels. In patients suffering from a cardiac disease, a reduced total ChE respectively BuChE activity was significantly associated with mortality and long-term major adverse cardiovascular events. The investigators hypothesize that the ChE activity in peripheral blood can be used as a potential biomarker, to early detect patients at high risk for postoperative delirium.

Official Title
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Delirium in Elderly Undergoing Cardiac Surgery and the Significance of CholinEsterase Activity Measured by Point of Care Method - a Prospective Observational Study

Conditions
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Postoperative Complications

Intervention / Treatment
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* Procedure: Elective cardiac surgery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Written informed consent ≥ 65 years of age Scheduled to undergo elective cardiac surgery (coronary artery bypass graft (CABG), valve surgery, combined CABG-valve surgery) with the use of CPB Both genders Exclusion Criteria: Planned deep hypothermic arrest Acute / emergency procedures Surgery without extracorporeal circulation (ECC) Patients with a history of pseudocholinesterase deficiency Employees of the respective study centres Illiteracy Severe communication difficulties and severe vision or hearing problems Patients legally unable to give written informed consent non-fluency in German language Severe psychiatric or neuropsychiatric disorders MMSE < 24 points, short geriatric depression scale (GDS) ≥ 10 points Recent (<6 months) history of alcohol or drug abuse The participation in a drug or device trial within the previous 30 days

Ages Eligible for Study
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Minimum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients undergoing cardiac surgery<br>Elderly patients scheduled to undergo elective cardiac surgery (coronary artery bypass graft (CABG), valve surgery, combined CABG-valve surgery) with the use of cardiopulmonary bypass. | Procedure: Elective cardiac surgery<br>* Coronary artery bypass graft (CABG), valve surgery, combined CABG-valve surgery<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Acetylcholinesterase (AChE) and buturylcholinesterase (BuChE) activity | The perioperative AChE and BuChE activity will be assessed in the whole blood by a point-of-care measuring instrument (ChE check mobile ®) and the association to the incidence and duration of postoperative delirium will be determined. It will be assessed preoperative and maximum until the 5th postoperative day (POD), minimum until the 3.POD. | 5 days | 
| Delirium | Postoperative delirium will be assessed preoperative and daily with the CAM / CAM-ICU test until the 5.POD and on the discharge day from hospital. The incidence of postoperative delirium will be associated with the perioperative AChE and BuChE time course. | 5-45 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pre-existing patient related risk factors | Influence of pre-existing patient related risk factors ( demographic data, medical and surgical history assessed preoperative) on postoperative delirium and the AChE and BuChE activity. | 1 day | 
| Identification of anticholinergic concomitant medication according to the PRISCUS list | Number of participants with preoperative anticholinergic medication | 1 day | 
| Survey of treatment associated data | Survey of treatment associated data until discharge (organ dysfunctions, postoperative pain, ICU length of stay, hospital length of stay, duration of mechanical ventilation, readmission rate to ICU, operation time, surgery, anaesthesia, intraoperative and postoperative volume load, postoperative mortality, comorbidities) | 45 days | 
| Cognitive function | Assessment of the cognitive function preoperative and on 3.POD and at discharge,by mini mental state examination (MMSE) | 45 days | 
| Routine venous blood parameters | Correlation of AChE and BuChE activity and routine venous blood parameters (Hb, Platelets, Leucocytes, INR, PTT, liver-enzymes (AST, ALT, y-GT, total Bilirubin), Creatinine, BUN, Albumin, sodium and potassium) and the influence on postoperative delirium | 5 days | 
| Inflammatory markers | Correlation of AChE and BuChE activity to inflammatory markers in serum and the influence on postoperative delirium | 5 days | 
| Follow up measure of functional decline according to the IADL scale | Patients will be followed up by phone on the 30. and 180.POD. Association of AChE and BuChE activity and the functional decline on the 30. and 180.POD. The preoperative IADL scale will be compared to the data on the 30. and 180.POD to assess the functional decline | 180 days | 
| Follow up measure of mortality | Patients will be followed up by phone on the 30. and 180.POD. Determination of the association between the peri-operative AChE and BuChE activity and the mortality on the 30. and 180.POD | 180 days | 
| Follow up measure of the number of MACCE-events | Patients will be followed up by phone on the 30. and 180.POD. Association of AChE and BuChE activity and the postoperative major adverse cardiovascular and cerebral events (MACCE) on the 30. and 180.POD. The number of events will be assessed. | 180 days | 
| Health related quality of life | Health related quality of life measured by EuroQuol EQ-5D-5L test preoperative, on 30.POD and 180. POD | 180 days | 
| Instrumental activities of daily living | The Lawton Instrumental Activities of Daily Living (IADL) Scale measured preoperative, on 30.POD and 180. POD | 180 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Postoperative delirium, Cholinesterase activity, Buturylcholinesterase activity, Acetylcholinesterase activity, Elderly patients, Cardiac surgery