Glycemic Variability and Autonomic Nervous System in Cardiac Surgery Patients

Study Overview
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Brief Summary
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On-pump coronary artery bypass graft (CABG) and valve replacement surgeries are high-risk procedures. Among the risk factors for postoperative complications, perioperative hyperglycemia and blood glucose variability have been reported to be associated with increased morbidity and mortality. The treatment of hyperglycemia using intravenous insulin infusion improves the prognosis in cardiac surgery patients. However, the determinants of postoperative blood glucose variability and the mechanisms leading to its deleterious impact are unknown. Thus, to date, there is no therapeutic intervention that could effectively prevent and treat the deleterious impact of glycemic variability on postoperative outcome. The purpose of the study is to evaluate whether perioperative alteration of the autonomic nervous system and preoperative blood glucose variability could be related to perioperative glycemic variability.

Detailed Description
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The main objective is to describe the relationship between preoperative glycemic variability and glycemic variability during the first 48 postoperative hours. The secondary objectives are : to describe the relationship between preoperative glycemic variability and glycemic variability during the first 48 hours postoperative according to: diabetic and non-diabetic status the type of surgical intervention to describe the relationship between the parameters evaluating the preoperative activity of the autonomic nervous system and: preoperative glycemic variability glycemic variability during the first 48 postoperative hours to describe the relationship between glycemic variability during the first 48 postoperative hours and: parameters evaluating the activity of the autonomic nervous system during the first 48 postoperative hours diabetes phenotype markers of inflammation markers of endothelial dysfunction to describe the morbidity and mortality within 30 days after surgery.

Official Title
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Perioperative Blood Glucose Variability and Autonomic Nervous System Activity in On-pump Cardiac Surgery Patients: Study Protocol of a Single-center Observational Study.

Conditions
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Blood Glucose Variability, Cardiac Surgical Procedures, Autonomic Nervous System

Intervention / Treatment
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* Procedure: coronary artery bypass surgery
* Procedure: aortic valve replacement surgery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Planned cardiac surgery Age ≥ 18 years old and < 80 years old Group 1: patients with known insulin-requiring type 2 diabetes mellitus undergoing planned on-pump coronary artery bypass surgery Group 2: patients with known non-insulin-requiring type 2 diabetes mellitus undergoing planned on-pump coronary artery bypass surgery Group 3: non-diabetic patients undergoing planned aortic valve replacement surgery Group 4: non-diabetic patients undergoing planned on-pump coronary artery bypass surgery Exclusion Criteria: Emergent surgery (less than 48 hours between anesthestetic consultation and surgery) Combined surgery (coronary artery bypass graft associated with valve surgery, multiple valve replacement, surgery of the ascending aorta) Extreme weight: body mass index (BMI) > 35 kg.m-2 or < 18 kg.m-2. Off-pump coronary artery bypass graft surgery Type 1 diabetes mellitus Patient unable to consent Pregnant and/or breastfeeding woman Permanent preoperative chronic heart rhythm disorder Pacemaker Unstable patient condition in preoperative period Expected life expectancy less than 48 hours. Subject unlikely to cooperate in the study and/or low cooperation anticipated by the investigator. Duration of continuous preoperative glycemic recording of less than 48 hours.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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 |
| --- | --- |
| Group 1<br>patients with known insulin-requiring type 2 diabetes mellitus undergoing planned on-pump coronary artery bypass graft surgery | Procedure: coronary artery bypass surgery<br>* coronary artery bypass surgery<br>|
| Group 2<br>patients with known non-insulin-requiring type 2 diabetes mellitus undergoing planned on-pump coronary artery bypass surgery | Procedure: coronary artery bypass surgery<br>* coronary artery bypass surgery<br>|
| Group 3<br>non-diabetic patients undergoing planned aortic valve replacement surgery | Procedure: aortic valve replacement surgery<br>* aortic valve replacement surgery<br>|
| Group 4<br>non-diabetic patients undergoing planned on-pump coronary artery bypass graft surgery | Procedure: coronary artery bypass surgery<br>* coronary artery bypass surgery<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glycemic variability, measured by subcutaneous blood glucose continuous monitoring sensor, calculated by the coefficient of glycemic variability | Continuous blood glucose monitoring using a subcutaneous blood glucose continuous monitoring sensor (FreeStyle Libre Pro) | From 14 days before surgery (at least 48 hours before surgery) to 7 days after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Autonomic nervous system activity, measured by non-invasive continuous heart rate monitoring, calculated by measuring the R-R interval | Continuous non-invasive continuous heart rate monitoring using the MooKy HR memory device will allow the continuous measurement of the R-R interval and the R-R interval variability to quantify the activity of the autonomic nervous system. | From the day before surgery (at admission in the cardiac surgery department the day before surgery) to Day 3 after surgery | 
| Vasopressine blood level | Vasopressine blood level will be measured from blood samples to assess the relationship between blood glucose variability and endothelial dysfunction. | The day before surgery, at admission in the postoperative intensive care unit, at day 1 and at day 2 after surgery | 
| Autonomic nervous system activity | Compass 31 scale: the Compass 31 scale is a validated clinical scale that allows to identify the degree au autonomic nervous system dysfunction. | The day before surgery. | 
| Endocan blood level | Endocan blood level will be measured from blood samples to assess the relationship between blood glucose variability and endothelial dysfunction. | The day before surgery, and at admission in the postoperative intensive care unit, and at day 1 and at day 2 after surgery. | 
| 8-iso PGF2a urinary level | 8-iso PGF2a urinary level will be measured from urinary samples to assess the relationship between blood glucose variability and oxidative stress. | The day before surgery, and at admission in the postoperative intensive care unit, and at day 1 and at day 2 after surgery. | 
| IL-6 blood level | IL-6 blood level will be measured from blood samples to assess the relationship between blood glucose variability and systemic inflammation. | The day before surgery, and at admission in the postoperative intensive care unit, and at day 1 and at day 2 after surgery. | 
| IL-10 blood level | IL-10 blood level will be measured from blood samples to assess the relationship between blood glucose variability and systemic inflammation. | The day before surgery, and at admission in the postoperative intensive care unit, and at day 1 and at day 2 after surgery. | 
| TNF-alpha blood level | TNF-alpha blood level will be measured from blood samples to assess the relationship between blood glucose variability and systemic inflammation. | The day before surgery, and at admission in the postoperative intensive care unit, and at day 1 and at day 2 after surgery. | 
| Angiotensine blood level | Angiotensine blood level will be measured from blood samples to assess the relationship between blood glucose variability and endothelial dysfunction. | The day before surgery, and at admission in the postoperative intensive care unit, and at day 1 and at day 2 after surgery. |