Mri characterIzation of Troponin Elevation After Cardiac Surgery

Study Overview
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Brief Summary
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Cardiac surgery under cardiopulmonary bypass (CPB) induces myocardial ischemia-reperfusion injury. This myocardial attack is a well-identified independent prognostic factor of postoperative morbidity and mortality. The quantification of these myocardial lesions by the postoperative plasma release of troponin has proven its diagnostic and prognostic value. Cardiac magnetic resonance imaging (MRI) can accurately measure and characterize the size of myocardial lesions. These lesions are associated with a poor prognosis. MRI can also characterize myocardial edema secondary to ischemia-reperfusion which has not yet been studied in the context of CPB. It is therefore necessary, in a mechanistic approach, to quantify the respective share of necrosis, edema and reperfusion lesions during cardiac surgery under CPB in order to better understand these phenomena and to propose effective strategies for the prevention of these myocardial lesions.the relationship between the postoperative release of troponin and the amount of myocardial necrosis and edema measured by cardiac MRI will be assessed.The hypothesis is to demonstrate a positive correlation between imaging and biology in order to better understand the perioperative myocardial lesion processes. This is an interventional study prospective, exploratory, in cardiac imaging, non-comparative and single-center, including 30 patients.

Official Title
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Characterization of Postoperative Myocardial Lesions by Cardiac MRI and Anatomo-biological Correlations With Serum Troponin in Cardiac Surgery.

Conditions
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Cardiac Surgery, Cardiopulmonary Bypass

Intervention / Treatment
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* Procedure: MRI
* Biological: Postoperative dosage of released troponin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years old Aortic valve surgery with CEC: aortic valve replacement, Bentall, Tirone-David, Wheat with foreseeable clamping time of at least 40 minutes. Informed consent signed Exclusion Criteria: Emergency surgery Other unconventional heart surgery Aorto-coronary bypass associated with surgery History of myocardial infarction or severe coronary artery disease, non-valvular hypertrophic cardiomyopathy (MHC) (primary MHC type, Amyloidosis) and myocarditis Preoperative alteration of systolic function of the left ventricle (LVEF <40%) Presence of a contraindication to cardiac MRI (claustrophobia, pacemaker or cardiac defibrillator, metallic body, hypersensitivity to gadolinium) Patients with a glomerular filtration rate (GFR) <30 ml / min Patients with permanent atrial fibrillation (ACFA) cardiac arrhythmia Patients treated with anthracyclines Pregnant and / or lactating woman Patient under legal protection Patient not benefiting from a social security system Patient participating in another clinical study that may interfere with the results of this study.

Ages Eligible for Study
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Minimum Age: 18 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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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: patients under aortic surgery with CPB<br>Patients under aortic surgery with CPB will have MRI and postoperative dosage of released troponin | Procedure: MRI<br>* 1 MRI 5 days after surgery (-1; +4 days), with intravenous administration of gadolinium<br>Biological: Postoperative dosage of released troponin<br>* Dosage of troponin I Hs H4, H8, H12, H24, H48, and H72 after the aortic cross-unclamping.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| correlation between cardiac MRI and the AUC of postoperative plasma released hsTnI. | Correlation between the AUC of plasma hsTnI levels measured during the first 72 hours postoperatively (sequential basal assays then 4, 8, 12, 24, 48 and 72 hours after aortic unclamping) and the mass in grams of myocardial necrosis measured by the late enhancement in cardiac MRI on D5 postoperative. Correlations between MRI anatomical data and biological or ultrasound data will be assessed with the Pearson or Spearman correlation coefficient according to the distribution of variables and linear regression. | 5 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Relationship between peak serum hsTnI and mass in grams of necrosis on MRI. | Correlation between highest serum value recorded for each patient within 72 hours and the mass in grams of myocardial necrosis measured by the late enhancement in cardiac MRI on D5 postoperative. | 5 days | 
| AUC / serum peak hsTnI relationship and relative size of the necrosis on MRI | Correlation between the AUC of plasma hsTnI levels measured during the first 72 hours postoperatively (sequential basal assays then 4, 8, 12, 24, 48 and 72 hours after aortic unclamping) and percentage of left ventricular mass. Correlation between highest serum value recorded for each patient within 72 hours and percentage of left ventricular mass. | 5 days | 
| Relationship of hsTnI levels at 24 hours after aortic unclamping and the mass in grams of necrosis on MRI. | Correlation between the AUC of plasma hsTnI levels measured at 24 hours after aortic unclamping and the mass in grams of myocardial necrosis measured by the late enhancement in cardiac MRI on D5 postoperative. | 5 days | 
| AUC / peak serum hsTnI relationship and intensity of edema | Correlation between the AUC of plasma hsTnI levels measured during the first 72 hours postoperatively (sequential basal assays then 4, 8, 12, 24, 48 and 72 hours after aortic unclamping) and intensity of edema at MRI. Correlation between highest serum value recorded for each patient within 72 hours and intensity of edema at MRI | 5 days | 
| AUC / hsTnI serum peak relationship and the presence of microvascular obstruction lesions on MRI on postoperative D5 | Correlation between the AUC of plasma hsTnI levels measured during the first 72 hours postoperatively (sequential basal assays then 4, 8, 12, 24, 48 and 72 hours after aortic unclamping) and the presence of microvascular obstruction lesions on MRI on postoperative D5. Correlation between highest serum value recorded for each patient within 72 hours and the presence of microvascular obstruction lesions on MRI on postoperative D5. | 5 days | 
| Relation of functional and anatomical parameters evaluated by cardiac MRI on postoperative D5. | Tele-diastolic volume / ventricular mass, LVEF on MRI on postoperative D5. | 5 days | 
| Correlations between clamping time and CEC and the size of the reperfusion lesions visible on MRI on D5 postoperative | Correlation between clamping time and the size of the reperfusion lesions visible on MRI on D5 postoperative. Correlation between CEC time and the size of the reperfusion lesions visible on MRI on D5 postoperative. | 5 days | 
| Exploratory evaluation of the kinetic profile of AUC with the type of lesion found on cardiac MRI (early peak, versus late peak). | Correlation between the kinetic profile of AUC and the type of lesion found on MRI on D5 postoperative. | 5 days | 
| Relation of functional and anatomical parameters of the right ventricle in 4 cavities and small axis (tele-diastolic volume, FEVD) evaluated by cardiac MRI on D5 postoperative. | Correlation between the right ventricle in 4 cavities and small axis (2 differents measures) on MRI on D5 postoperative. | 5 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cardiac surgery, Cardiopulmonary bypass, ischemia reperfusion, Cardiac magnetic resonance imaging